Polyamide molded composite material, method for producing the same, and use

Abstract

The present invention is mainly based on the selection of a semi-aromatic polyamide resin having a specific repeating unit, and the crystal peak half-width ΔT 1 / 2 We provide semi-aromatic polyamide molding composite materials that have the advantages of reducing blue light, high contrast, and high gradation, and can meet the needs of packaging process and long-term reliability, with a temperature range of 4-11°C, whiteness adjustment of less than 26.5, and 460nm light source reflectance of less than 6%. The cellularized products can be used to manufacture light source reflecting brackets of high-contrast LED displays for multi-scenario applications.

Description

[Technical Field]

[0001] The present invention relates to the technical field of polymer materials, and more particularly to polyamide molded composite materials, and to methods for producing and using the same. [Background technology]

[0002] An LED light source is primarily composed of a semiconductor chip, an LED light source reflective bracket, gold wire, and package adhesive. The LED light source reflective bracket is the "skeleton" of the LED light source and also a functional component. The LED packaging process requires die attachment, wire bonding, and curing of the package adhesive, and all other materials and components are integrated into the reflective bracket. The LED reflective bracket needs to reflect the light emitted by the LED chip at a specific angle to reduce light loss, transmit light through the package material such as epoxy resin or silicone, and form the light source for LED lighting and displays. The LED reflective bracket material is the core material of LED lighting and is directly related to the performance and lifespan of the LED light source.

[0003] Currently, the following points need to be considered when selecting materials for LED reflective brackets.

[0004] Firstly, throughout the packaging process, the LED reflective bracket is exposed to temperatures of 150-200°C for 6-10 hours. Furthermore, if the lamp beads are to be used in a display after packaging, SMT (Surface Mount Manufacturing) is required. The LED bracket and lamp beads must not deform or break under load during packaging and SMT, and there are high requirements for the adhesion of the LED bracket material.

[0005] Secondly, in recent years, LED display light sources have been gradually developed for narrow-pitch displays with a point pitch of P2.5 or less. As a result, the research and development and manufacturing of LED displays continue to face significant challenges in this process. The manufacturing of brackets for small-pitch displays is gradually progressing towards thinner walls, multi-cavity designs, and miniaturization, requiring stricter requirements for the fluidity of LED reflective bracket materials, the moldability of ultra-multi-cavity designs, and mechanical strength.

[0006] Thirdly, LED lighting fixtures and displays are often affected by adverse weather conditions such as high temperatures, typhoons, heavy rain, and lightning during use, depending on the environment. Therefore, there are high requirements for the dimensional stability and other performance characteristics of the materials used to protect lighting fixtures and displays from adverse weather conditions.

[0007] Fourthly, in the application fields of LED displays, brightness and contrast are crucial indicators for displaying clear image quality. Currently, the form mainly used on the market is an LED bracket made of pure white LED reflective material, which requires silk-screen printing of black ink onto the surface. This process is complicated, negatively impacts efficiency, and is costly. However, the sides and surface of the reflective cup remain white, reducing the contrast and gradation of the LED display.

[0008] Fifth, regarding light sources, the wavelengths that the average person's eye can perceive are 780-400nm. Of these, short-wave blue light with a wavelength of 400-450nm causes the most damage to the retina. This wavelength of blue light increases the amount of toxins in the macular region of the eye, seriously threatening people's eye health. On the other hand, LED full-color display light sources are packaged with three types of chips: red (R), green (G), and blue (B). Of these, the blue chip emits the lowest brightness of light, meaning it has the highest contrast. Therefore, the reflectivity of the blue light of the chip used in the LED light source bracket directly affects the overall contrast of the LED display. Blue light prevention using LED screens is widespread in various mobile phones and televisions, and the common measure is to coat the screen surface with a blue light prevention film, but each of these thin films has the drawback of being fragile and expensive.

[0009] Those skilled in the art have primarily focused on the first and second points mentioned above when improving LED reflective bracket materials. They have paid little attention to the water absorption rate and dimensional stability of polyamide molded composite materials, and have not improved the contrast and gradation of LED display brackets by improving the contrast and gradation of the material itself. [Overview of the Initiative]

[0010] The objective of the present invention is to solve the above-mentioned technical defects and provide a semi-aromatic polyamide molded composite material that has high contrast and high gradation and can meet the needs of packaging processes and long-term reliability. Another object of the present invention is to provide the use of the above-described semi-aromatic polyamide molded composite material. [Means for solving the problem]

[0011] This invention is achieved through the following technical solutions.

[0012] A semi-aromatic polyamide molded composite material, The ingredients include 40-75 parts by weight of PA10T / X resin, 30-60 parts by weight of wollastonite, and 0.5-4.5 parts by weight of toner. PA10T / X mol%, where the content of 10T units is 80-95 mol%, and the content of X units is 5-20 mol%, where X units consist of diacid units and diamine units, where the diacid units are at least one selected from terephthalic acid units, isophthalic acid units, 1,6-adipic acid units, and 1,10-sebacic acid units, and the diamine units are 1,6-hexamethylenediamine units, 1,9-nonanediamine units, and 2-methyl-1,5- Pentanediamine It is at least one selected from the units, 2-methyl-1,8-octanediamine units, 1,10-decanediamine units, and 1,12-dodecanediamine units. In the resin matrix of semi-aromatic polyamide molded composite materials, wollastonite has an average diameter of 4-20 μm and an average length of 10-250 μm. The crystal peak width at half maximum (ΔT) was measured by differential scanning calorimetry at a temperature of 20°C / min after heating to 345°C. 1 / 2 The temperature range is 4-11℃. The whiteness is less than 26.5, and the reflectance of the 460nm light source is less than 6%.

[0013] The unit X is not 10T.

[0014] The PA10T / X resin is at least one selected from PA10T / 10I, PA10T / 6T, PA10T / 66, PA10T / 1010, PA10T / 610, PA10T / 612, and PA10T / 12T.

[0015] Preferably, the semi-aromatic polyamide molded composite material is measured by differential scanning calorimetry at a temperature of 20°C / min after heating to 345°C, and then measuring the crystal peak width at half maximum ΔT. 1 / 2 The temperature is 5-8°C.

[0016] The PA10T / X resin of the present invention may be a commercially available product or may be synthesized by the following method. For more accurate experiments, the PA10T / X used in the examples and comparative examples of the present invention is a self-prepared sample, and raw materials such as monomers and capping agents are commercially available products.

[0017] (1) Preliminary polymerization: Charge the polymerization reaction monomers (dicarboxylic acid, diamine), benzoic acid as the capping agent, and deionized water into a stainless steel high-pressure reactor equipped with mechanical stirring. After performing vacuum suction and N2 substitution three times, start heating and stirring, heat up to 170 - 190 °C at a heating rate of 4 - 6 °C / min, keep the temperature for 1 - 2 hours, then heat up to 260 - 280 °C at a heating rate of 1 - 3 °C / min, stir slowly, keep the temperature for 3 - 5 h, and let the preliminary polymerization reaction proceed sufficiently. After the heat preservation is completed, slowly heat up to 270 - 290 °C and start draining until normal pressure. When the normal pressure is reached, close the drain valve to end the reaction, lower the temperature to room temperature, and discharge the material.

[0018] (2) Solid-phase thickening: Put the material produced in the preliminary polymerization process into a vacuum rotary drum, and set the rotation speed of the rotary drum to 10 - 15 r / min and the vacuum degree to 25 - 35 Pa. Heat up at a rate of 15 - 25 °C / min, sample and measure the viscosity when the temperature reaches 260 - 270 °C, and determine the end point of the material according to the result of the viscosity (or number average molecular weight). The number average molecular weight of the PA10T / X resin is 1500 - 28000. The measurement method of the number average molecular weight is a conventional method. Specifically, the number average molecular weight (Mn) of the PA10T / X resin sample is measured by gel permeation chromatography (GPC). Composition of Agilent HPLC-1260 high-performance liquid chromatograph: Eppendorf column oven, Shodex KF-801, 802, 802.5 and 803 gel permeation chromatography columns, differential detector, G7129A autosampler. Use hexafluoroisopropanol as the mobile phase and measure the molecular weight of the resin under the condition of a column temperature of 40 °C. Process this data with chromatographic workstation cirrus software to obtain the number average molecular weight distribution Mn.

[0019] Preferably, the wollastonite in the resin matrix of the semi-aromatic polyamide molding composite material has an average diameter of 6 to 13 μm and an average length of 80 to 120 μm. Wollastonite is a powder having a certain aspect ratio, its microstructure is fibrous, and its length and diameter hardly change during melt shearing in a screw. By experiment, PA10T / X For two substances, wollastonite (average diameter 17 μm, average length 180 μm), after undergoing melt shearing and blending through the production process, and further dissolving the resin using a solvent, and measuring the average diameter and average length of the wollastonite, it was found that the diameter of the wollastonite does not change during shearing by the screw, and the average length changes by about 0.5%.

[0020] The toner is a mixed toner of at least one or more colors selected from carbon black, black masterbatch, and amorphous carbon toner.

[0021] Preferably, the toner is selected from amorphous carbon toner.

[0022] Preferably, the reflectance of the semi-aromatic polyamide molding composite material to a 460 nm light source is less than 4.5%, and more preferably, the reflectance of the semi-aromatic polyamide molding composite material to a 460 nm light source is less than 3.8%.

[0023] It further contains 0 to 3 parts by weight of an antioxidant, and the antioxidant is at least one selected from hindered phenolic antioxidants, hindered amine antioxidants, phosphite antioxidants, thiol antioxidants, and thiodipropionate antioxidants.

[0024] The use of the semi-aromatic polyamide molding composite material of the present invention is used for manufacturing a light source reflection bracket of an LED display.

[0025] The present invention provides a method for producing a semi-aromatic polyamide molded composite material, comprising adding each component to a mixer and mixing them uniformly, then extruding and granulating the mixture using a twin-screw extruder to obtain a semi-aromatic polyamide molded composite material with a screw temperature range of 280 to 330°C and a rotation speed of 450 r / min. [Effects of the Invention]

[0026] The present invention has the following beneficial effects.

[0027] The reflectivity of a 460nm light source correlates primarily with the surface roughness of the material (the higher the value of the surface roughness within a certain range, the more the light emitted from the light source is diffusely reflected by the surface of the object, resulting in less light energy received at the light-receiving end) and the whiteness of the material (the lower the whiteness, the lower the reflectivity). The influence of the light source reflective bracket of an LED display on the gradation and contrast of the LED display is mainly due to the whiteness and reflectivity of the light source reflective bracket. According to this principle, the semi-aromatic polyamide molded composite material of the present invention has the advantage of controlling the whiteness to less than 26.5 and the reflectivity of a 460nm light source to less than 6% (improving gradation and contrast), having long-term package stability (adhesion), and having low blue light emission from the LED screen packaged therein, in the following three respects.

[0028] Firstly, compared to other inorganic fillers, wollastonite can achieve the requirement of reducing the surface roughness of semi-aromatic polyamide molded composite materials to reduce 460nm light reflectivity, not only lowering the reflectivity of 460nm light sources but also improving adhesion to metals. The preferred distribution dimensions of wollastonite in the resin matrix can further reduce the reflectivity of 460nm light sources (reducing blue light from LED displays) and improve adhesion to metals.

[0029] Secondly, by adjusting the color of the material with toner, a black color with good light absorption effect can be obtained. Preferably, amorphous carbon toner further reduces whiteness, improves light absorption, and reduces the reflectance of a 460nm light source.

[0030] Thirdly, the crystal peak full width at half maximum (FWHM) of the semi-aromatic polyamide molded composite material also clearly affects the reflectance of the composite material under a 460nm light source, and the crystal peak FWHM ΔT 1 / 2 Experiments have shown that products manufactured at temperatures between 4 and 11°C exhibit lower reflectivity under a 460nm light source. In the technical solution of the present invention, the crystal peak full width at half maximum of the semi-aromatic polyamide molded composite material is primarily adjusted by adjusting the amount and specifications of toner and wollastonite, but may also be adjusted by adjusting the number-average molecular weight of the semi-aromatic polyamide resin. On the other hand, excellent adhesion can be obtained by adjusting the crystal peak full width at half maximum, the specifications of wollastonite, and the surface roughness of the PA10T / X molded composite material.

[0031] The semi-aromatic polyamide molded composite material of the present invention does not require additional spraying or matting of light-absorbing paint, thereby reducing the cost of light source brackets for LED displays. [Modes for carrying out the invention]

[0032] The present invention will be described in detail below with reference to specific examples. The following examples will facilitate a further understanding of the present invention by those skilled in the art, but will not limit the present invention in any form. Those skilled in the art may make some modifications and improvements without departing from the concept of the present invention. All of these will fall within the scope of protection of the present invention.

[0033] The raw materials used in the examples and comparative examples are as follows:

[0034] The following monomers for polyamide polymerization are commercially available, polymerization-grade, and pure. PA10T / 10¹⁰-1:10T unit content is 80 mol%, number-average molecular weight is 7500, crystal peak half-width ΔT 1 / 2 The temperature was 15.1℃, and it was made by the user by referring to the method described in the summary of the invention. PA10T / 10¹⁰-2:10T unit content is 85 mol%, number-average molecular weight is 9000, crystal peak half-width ΔT 1 / 2is 16°C and was made by oneself referring to the method described in the summary of the invention. PA10T / 1010-3: The content of 10T unit is 90 mol%, the number average molecular weight is 8500, and the full width at half maximum of the crystallization peak ΔT 1 / 2 is 12.8°C and was made by oneself referring to the method described in the summary of the invention. PA10T / 1010-4: The content of 10T unit is 95 mol%, the number average molecular weight is 13000, and the full width at half maximum of the crystallization peak ΔT 1 / 2 is 8.4°C and was made by oneself referring to the method described in the summary of the invention. PA10T / 1010-5: The content of 10T unit is 90 mol%, the number average molecular weight is 4300, and the full width at half maximum of the crystallization peak ΔT 1 / 2 is 14.2°C and was made by oneself referring to the method described in the summary of the invention. PA10T / 1010-6: The content of 10T unit is 90 mol%, the number average molecular weight is 21000, and the full width at half maximum of the crystallization peak ΔT 1 / 2 is 18.3°C and was made by oneself referring to the method described in the summary of the invention. PA10T / 1010-7: The content of 10T unit is 75 mol%, the number average molecular weight is 8800, and the full width at half maximum of the crystallization peak ΔT 1 / 2 is 18.0°C and was made by oneself referring to the method described in the summary of the invention. PA10T / 1010-8: The content of 10T unit is 97 mol%, the number average molecular weight is 8000, and the full width at half maximum of the crystallization peak ΔT 1 / 2 is 7.5°C and was made by oneself referring to the method described in the summary of the invention. PA10T / 10I-1: The content of 10T unit is 80 mol%, the number average molecular weight is 10500, and the full width at half maximum of the crystallization peak ΔT 1 / 2 is 17.1°C and was made by oneself referring to the method described in the summary of the invention. PA10T / 10I-2: The content of 10T unit is 85 mol%, the number average molecular weight is 9800, and the full width at half maximum of the crystallization peak ΔT 1 / 2 is 12°C and was made by oneself referring to the method described in the summary of the invention. PA10T / 10I-3: The content of 10T unit is 90 mol%, the number average molecular weight is 8500, and the full width at half maximum of the crystallization peak ΔT1 / 2 The temperature was 8.3℃, and it was made by the user by referring to the method described in the summary of the invention. PA10T / 10I-4:10T unit content is 95 mol%, number-average molecular weight is 8000, crystal peak half-width ΔT 1 / 2 The temperature was 7.1℃, and it was manufactured by the user by referring to the method described in the summary of the invention. PA10T / 10I-5:10T unit content is 60 mol%, number-average molecular weight is 8000, crystal peak half-width ΔT 1 / 2 The temperature was 15℃, and it was made by the user by referring to the method described in the summary of the invention. PA10T / 66: 10T unit content is 90 mol%, number-average molecular weight is 8000, crystal peak half-width ΔT 1 / 2 The temperature was 13.4℃, and it was made by the user by referring to the method described in the summary of the invention. PA10T / 12T: 10T unit content is 80 mol%, number-average molecular weight is 8000, crystal peak full width at half maximum ΔT 1 / 2 The temperature was 10.6℃, and it was made by the user by referring to the method described in the summary of the invention. Wollastonite A: average diameter 4 μm, average length 60 μm; Wollastonite B: average diameter 6 μm, average length 120 μm; Wollastonite C: average diameter 13 μm, average length 80 μm; Wollastonite D: Average diameter 17 μm, average length 180 μm. The wollastonite used in this invention is obtained by screening commercially available products to achieve the desired average diameter and length range. Talcum powder: AH-1250, Guangxi Longsheng Huamei Talc Development Co., Ltd. Toner A: Amorphous carbon toner N774, Tianjin Tianyang Qiushi Chemical Technology Co., Ltd. Toner B: Carbon Black M570, Cabot Chemical Corporation; Toner C: Black Masterbatch UN2014, Cabot Chemical Corporation; Toner D: Mazcol Blue 153K, Shenzhen Dintai Chemical Co., Ltd. Antioxidant: Irganox 1098, a hindered phenol antioxidant.

[0035] Examples and Comparative Examples Method of producing semi-aromatic polyamide molded composite material: PA10T / X resin, wollastonite, toner, and antioxidant are added to a mixer and mixed uniformly. Then, the mixture is extruded and granulated using a twin-screw extruder with a screw temperature range of 280-330°C and a rotation speed of 450 r / min to obtain a semi-aromatic polyamide molded composite material. Test method:

[0036] (1) Adhesion: For samples of PA10T / X molded composite material, the adhesion between the bracket plastic and metal is expressed through a red ink test. An LED reflective cup, formed by in-mold injection molding of the light source bracket material of an LED display and plated metal strip material, is immersed in red ink. The pins are positioned so that they are immersed in the red ink, and it is observed whether the red ink penetrates into the interior of the reflective cup. If the red ink does not penetrate the reflective cup within 5 minutes, the adhesion grade is judged to be A. If the red ink does not penetrate the reflective cup within 3 minutes, but does penetrate within 5 minutes, the adhesion grade is judged to be B. If the red ink does not penetrate the reflective cup within 1 minute, but does penetrate within 3 minutes, the adhesion grade is judged to be Class C. If the red ink penetrates the reflective cup within 1 minute, the adhesion grade is judged to be Class D. A D-grade adhesion rating indicates poor adhesion between the plastic and metal, posing a risk of lamp bead failure. Conversely, an A, B, or C-grade adhesion rating indicates excellent airtightness and reliability of the packaged lamp beads.

[0037] (2) Whiteness: The contrast of a material is evaluated using its whiteness as an indicator. PA10T / X For a test specimen measuring 60 mm in length, 60 mm in width, and 1 mm in thickness, which was injection-molded from a composite material, the L, a, and b values ​​were measured using a Color Eye 7000A colorimeter, and the whiteness was calculated. W H =100-[(100-L) 2 +a2 +b 2 ] 1 / 2 .

[0038] (3) Reflectance: A test specimen measuring 60 mm in length, 60 mm in width, and 1 mm in thickness, made by injection molding PA10T / X molded composite material, is used to measure the reflectance of the test specimen to light with a wavelength of 460 nm using a Color Eye 7000A colorimeter.

[0039] (4) Crystal peak width at half maximum ΔT of semi-aromatic polyamide molded composite materials 1 / 2 Using a differential scanning calorimetry analyzer manufactured by NETZSCH, the temperature was increased from 30°C to 345°C at a rate of 20°C / min under a nitrogen atmosphere, maintained for 2 minutes, and then cooled at a rate of 20°C / min. The crystal peak temperature observed at this time was defined as the crystallization temperature Tc (°C), and the crystal peak width at half maximum (FMAX) ΔT was defined as half the measured peak width. 1 / 2 Let's assume that.

[0040] [Table 1]

[0041] Examples 1 to 6 show that by adjusting the amount of wollastonite added, the crystal peak full width at half maximum of the semi-aromatic polyamide molded composite material can be controlled to a desirable range, improving not only the adhesion grade but also the reflectivity.

[0042] [Table 2]

[0043] Examples 4, 7-10 showed that adjusting the amount of toner used reduced whiteness and reflectivity.

[0044] [Table 3]

[0045] Examples 4, 13-17 show that wollastonite preferably has an average diameter of 6-14 μm and an average length of 80-120 μm, and that even when the crystal peak full width at half maximum of the composite material is not in the range of 5-8°C, the adhesion grade can be further improved and the reflectance can be further reduced, and the toner is preferably an amorphous carbon toner.

[0046] [Table 4]

[0047] Examples 4, 18-24 show that by adjusting the initial crystal full width at half maximum (FWHM) of a semi-aromatic polyamide resin with wollastonite and toner, the crystal FWHM can be varied to a range of values, resulting in semi-aromatic polyamide molded composite materials with various adhesion grades and reflectivity.

[0048] [Table 5]

[0049] [Table 6]

[0050] Comparative Examples 1, 2, and 3 showed that the X content in the PA10T / X repeating units had a significant impact on the adhesion grade. The change in surface properties also led to an increase in reflectivity and a significant impact on adhesion.

[0051] Comparative Example 4 showed that talc powder cannot be used as a substitute for wollastonite.

[0052] Comparative Example 5 showed that if the wollastonite content exceeds a certain limit, it becomes impossible to adjust the crystal peak full width at half maximum to 4-11°C, resulting not only in inferior adhesion grade but also high reflectivity.

[0053] Comparative Example 6 showed that when the wollastonite content is too high, even if the crystal peak full width at half maximum can be set to 4-11°C, both the adhesion grade and reflectance are high. This is because too much wollastonite destroys the surface structure of the composite material, and also because, since wollastonite is a white powder, an excess amount increases the whiteness.

[0054] [Table 7]

[0055] Comparative Example 7 showed that if the amount of toner added is too low, the whiteness becomes too high, resulting in a high reflectivity.

[0056] Comparative Example 8 showed that if too much toner is added, the toner becomes excessively concentrated on the surface, affecting adhesion and reflectivity.

Claims

1. A semi-aromatic polyamide molded composite material, The ingredients include 40 to 75 parts by weight of PA10T / X resin, 35 to 60 parts by weight of wollastonite, and 0.5 to 4.5 parts by weight of toner. In PA10T / X mol%, the content of 10T units is 80-95 mol%, and the content of X units is 5-20 mol%. The PA10T / X resin is at least one selected from PA10T / 10I, PA10T / 6T, PA10T / 66, PA10T / 1010, PA10T / 610, and PA10T / 12T. In the resin matrix of semi-aromatic polyamide molded composite materials, wollastonite has an average diameter of 6–13 μm and an average length of 80–120 μm. The crystal peak width at half maximum (ΔT) was measured by differential scanning calorimetry at a temperature of 20°C / min after heating to 345°C. １／２ The temperature ranges from 4 to 11°C. A semi-aromatic polyamide molded composite material characterized by having a whiteness of less than 26.5 and a 460 nm light source reflectance of less than 6%.

2. The crystal peak width at half maximum (ΔT) was measured by differential scanning calorimetry at a temperature of 20°C / min after heating to 345°C. １／２ The semi-aromatic polyamide molded composite material according to claim 1, characterized in that the temperature is 5 to 8°C.

3. The semi-aromatic polyamide molded composite material according to claim 1, characterized in that the number average molecular weight of the PA10T / X resin is 1,500 to 28,000.

4. The semi-aromatic polyamide molded composite material according to claim 1, characterized in that the toner is a mixed toner of at least one or more colors selected from carbon black, black masterbatch, and amorphous carbon toner.

5. The semi-aromatic polyamide molded composite material according to claim 4, characterized in that the toner is selected from amorphous carbon toners.

6. The semi-aromatic polyamide molded composite material according to claim 1, characterized in that the reflectance of a 460 nm light source is less than 4.5%.

7. The semi-aromatic polyamide molded composite material according to claim 6, characterized in that the reflectance of a 460 nm light source is less than 3.8%.

8. The semi-aromatic polyamide molded composite material according to claim 1, further comprising 0.5 to 3 parts by weight of an antioxidant.

9. A method for producing a semi-aromatic polyamide molded composite material according to any one of claims 1 to 8, characterized by comprising the steps of adding each component to a mixer and mixing them uniformly, and then extruding and granulating the mixture using a twin-screw extruder with a screw temperature range of 280 to 330°C and a rotation speed of 400 to 500 r / min to obtain a semi-aromatic polyamide molded composite material.

10. Use of the semi-aromatic polyamide molded composite material according to any one of claims 1 to 8, characterized in that it is used in the manufacture of a light source reflective bracket for an LED display.

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