A polyester composition, a preparation method thereof and an application thereof

Abstract

The present invention discloses a polyester composition, which comprises the following components by weight: 50 - 80 parts of PCT resin; 8 - 40 parts of filler; 0.01 - 0.1 part of light diffusing agent, and the filler is selected from at least one of flat glass fiber, round glass fiber and glass flake. The present invention can significantly improve the light reflectivity and also has a certain light transmittance (the light transmittance range is 53% - 75%, and the reflectivity range is 44% - 64%) mainly by adding a specific light diffusing agent, and can increase the reflection angle; and the advantages of high temperature resistance are obtained by selecting a specific polyester resin. It is suitable for preparing SMD type LED reflection brackets.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly relates to a preparation method and application of a polyester composition. Background Art

[0002] The SMD type LED reflection bracket is to put the punched, formed and electroplated metal strip into the injection mold, and then inject the LED reflection bracket material onto the metal strip through an injection molding machine, so that the LED reflection bracket material and the metal strip are made into an LED functional part with a reflection cavity that can be SMT soldered. After die bonding, wire bonding and encapsulation, the light emitted by the LED chip is reflected at a certain angle to reduce light loss, and then passes through encapsulation materials such as epoxy resin or silica gel to form a light source for LED lighting or display. It can be said that the LED reflection bracket material is a core material for LED lighting, which directly affects the brightness and lifespan of the LED light source. The function of LED encapsulation is to provide sufficient protection for the chip to prevent the chip from failing due to long-term exposure to air or mechanical damage, so as to improve the stability of the chip.

[0003] Common SMD type LED reflection bracket materials are thermoplastic materials filled with PPA or PCT, reinforcing fillers and titanium dioxide. Since titanium dioxide is a light-shielding pigment, the current SMD type LED reflection bracket materials on the market are opaque and light-shielding materials. Therefore, the light-emitting angle of the encapsulated lamp beads cannot reach 180°, as shown in the attached specification. Figure 1 Currently, in order to maximize the light-emitting angle of the lamp beads in the industry, a method of adding a PMMA lens outside the SMD lamp beads is adopted, as shown in the attached specification. Figure 2 Although this method can improve the light-emitting angle of the SMD lamp beads, it requires adding a lens, and both the process and cost need to increase investment.

[0004] At the same time, the SMD type LED reflection bracket materials need to add fillers such as titanium dioxide. Although it can improve the reflectivity of the materials, it has a greater impact on the strength and toughness of the materials, resulting in problems such as cracking and dead lights during the use of SMD type lamp beads. Summary of the Invention

[0005] The purpose of the present invention is to provide a polyester composition, which has a certain light transmittance while having a high light reflectivity, and increases the reflection angle. The present invention also discloses its preparation method and application.

[0006] The present invention is achieved through the following technical solutions:

[0007] A polyester composition, by weight, comprises the following components:

[0008] 50 - 80 parts of PCT resin;

[0009] 8 - 40 parts of filler;

[0010] 0.01 - 0.1 part of light diffusing agent;

[0011] The filler is selected from at least one of flat glass fiber, round glass fiber, and glass flake;

[0012] The structure of the light diffusing agent is

[0013]

[0014] Among them, R2, R3, R4, and R5 are each independently one of a hydrogen atom, an alkyl group with 1 - 6 carbon atoms, an aryl group with 1 - 9 carbon atoms, a halogen atom, a heterocyclic group with 1 - 6 carbon atoms, an ester group with 1 - 6 carbon atoms, and a cyano group;

[0015] R1 is

[0016] One of the following.

[0017] Preferably, R1 is One of the following.

[0018] Preferably, the content of the light diffusing agent is 0.0005 - 0.001 times the weight content of the PCT resin.

[0019] In the polyester composition, the aspect ratio (retained length / major axis diameter) of the flat glass fiber ranges from 0.3 - 228, preferably 1 - 200, more preferably 3 - 100;

[0020] Preferably, the flatness ratio of the flat glass fiber is 2 - 7, preferably 4 - 6.

[0021] In the polyester composition, the aspect ratio of the round glass fiber ranges from 2 - 352; preferably, the aspect ratio of the round glass fiber ranges from 5 - 300, more preferably 15 - 200.

[0022] In the polyester composition, the D50 particle size of the glass flake ranges from 5 - 250 microns; preferably, the D50 particle size of the glass flake ranges from 10 - 200 microns, more preferably 20 - 160 microns.

[0023] The melting point of the PCT resin measured by differential scanning calorimetry at a heating / cooling rate of 20 °C / min is 260 - 300 °C.

[0024] According to actual requirements, it is possible to choose whether to add at least one of 0 - 2 parts of antioxidant and lubricant.

[0025] The antioxidant can be: 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene; 2,5-di-tert-butyl-4-hydroxybenzyl dimethylamine; diethyl 3,5-di-tert-butyl-4-hydroxybenzyl phosphate; stearyl 3,5-di-tert-butyl-4-hydroxybenzyl phosphate; 3,5-di-tert-butyl-4-hydroxyphenyl-3,5-distearyl-thiotriazolylamine; 2,6-di-tert-butyl-4-hydroxymethylphenol; 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylglycidyl allyl ether)-1,3,5-triazine; N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxy-hydrocinnamide); N,N'-bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexanediamine; octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; pentaerythrityl tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]; triethylene glycol bis[3-(3,5-dimethyl-4-hydroxyphenyl)propionate]; diethylene glycol bis[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate]; 2,2'-thiodiethyl bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], etc.

[0026] The lubricant can be at least one of stearate lubricants, fatty acid lubricants, and stearate ester lubricants; the stearate lubricants are selected from at least one of calcium stearate, magnesium stearate, and zinc stearate; the fatty acid lubricants are selected from at least one of fatty acids, fatty acid derivatives, and fatty acid esters; the stearate ester lubricants are selected from at least one of pentaerythritol stearate.

[0027] The preparation method of the high-temperature resistant polyester composition of the present invention includes the following components: according to the ratio, mixing polyester resin, filler, and light diffusing agent in a high-speed mixer, and melting and blending the mixture through a twin-screw extruder and extruding and pelletizing to obtain a high-temperature resistant polyester composition; wherein the heating temperature of the extruder is as follows: zone 1: 250-290°C, zones 2-4: 260-300°C, zones 5-7: 270-310°C, zones 8-9: 260-300°C, and the die head: 250-290°C.

[0028] The glass fiber can be long glass fiber or chopped glass fiber. If continuous glass fiber is selected, it is fed in laterally. The chopped glass fiber is a product in which the manufacturer has pre-cut the continuous glass fiber into short lengths.

[0029] The 60×60×1.0 mm molded product prepared from the high-temperature resistant polyester composition of the present invention under the condition of a mold temperature of 60°C has a light transmittance range of 53%-75% and a reflectance range of 44%-64%.

[0030] The present invention has the following beneficial effects:

[0031] By adding a light diffusing agent with a specific content and structure, the high-temperature resistant polyester composition of the present invention can excite and absorb invisible light (wavelength range of about 60 - 380 nm), convert it into blue light with a longer wavelength, and at the same time reflect more blue light with a wavelength in the range of 400 - 600 nm than the originally incident light, thereby significantly improving the light reflectivity of the polyester composition. At the same time, in cooperation with glass fillers such as flat glass fibers, round glass fibers, and glass flakes with specific contents and morphologies, the reflectivity can be further improved with little effect on the light transmittance. When applied to SMD type LED reflection brackets, the reflection angle can be increased (as shown in the attached Figure 3 description); and the polyester composition of the present invention has the advantage of high temperature resistance. It is suitable for preparing SMD type LED reflection brackets. Description of the Drawings

[0032] Figure 1 : Schematic structural diagram of an opaque SMD type LED reflection bracket material on the current market.

[0033] Figure 2 : Schematic structural diagram of adding a PMMA lens outside the SMD lamp bead.

[0034] Figure 3 : Schematic diagram of light reflection of the high-temperature resistant polyester composition of the present invention applied to an SMD type LED reflection bracket. Detailed Embodiments

[0035] 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 belong to the protection scope of the present invention.

[0036] The sources of the raw materials used in the present invention are as follows:

[0037] PCT resin A: PCT 0502, SK Chemicals. Melting point 286 °C (measured at a heating / cooling rate of 20 °C / min);

[0038] PCT resin B: PCT 0502HC, SK Chemicals. Melting point 295 °C (measured at a heating / cooling rate of 20 °C / min);

[0039] Light diffusing agent A:

[0040]

[0041] OB-1, Zhejiang Hongyi Chemical Co., Ltd.;

[0042] Light diffusing agent B:

[0043]

[0044] KSN, Zhejiang Hongyi Chemical Co., Ltd.;

[0045] Light diffusing agent C:

[0046]

[0047] Commercially available, CAS 2866 - 43 - 5.

[0048] Light diffusing agent D:

[0049]

[0050] DT, (CAS No: 1041 - 00 - 5), Zhejiang Hongyi Chemical Co., Ltd.;

[0051] Light diffusing agent E: Acrylic light diffusing powder TY - 660, Hunan Jinyu Fine Chemical Co., Ltd.

[0052] Titanium dioxide: BLR - 886, purchased from Longmang Baili.

[0053] Round glass fiber A: Grade ECS10 - 03 - 568H, manufacturer JUSHI;

[0054] Flat glass fiber A: Aspect ratio 2, CPIC;

[0055] Flat glass fiber B: Chopped, aspect ratio 3, manufacturer CPIC;

[0056] Flat glass fiber C: Chopped, aspect ratio 4, manufacturer CPIC;

[0057] Flat glass fiber D: Chopped, aspect ratio 6, CPIC;

[0058] Glass flakes were purchased from the UK company Glassflake and then specific particle size raw materials were obtained through screening.

[0059] Glass flake A: D50 = 11.6 microns;

[0060] Glass flake B: D50 = 23.5 microns;

[0061] Glass flake C: D50 = 158.4 microns;

[0062] Glass flake D: D50 = 199.5 microns;

[0063] Glass flake E: D50 = 5.3 microns;

[0064] Glass flake F: D50 = 239.7 microns;

[0065] The test method for D50 particle size is as follows: the particle size value corresponding to the cumulative distribution percentage reaching 50% is measured using a Malvern wet laser particle size analyzer. Preparation method of the high-temperature resistant polyester composition in the examples and comparative examples: according to the ratio, polyester resin, filler, and light diffusing agent are mixed in a high-speed mixer, and the mixture is melt-blended and extruded into pellets through a twin-screw extruder to obtain the high-temperature resistant polyester composition; the heating temperatures of the extruder are as follows: zone 1: 250 - 290 °C, zones 2 - 4: 260 - 300 °C, zones 5 - 7: 270 - 310 °C, zones 8 - 9: 260 - 300 °C, and the die head: 250 - 290 °C. The retention aspect ratio of glass fiber is controlled by adjusting the shear strength of the screw, or the glass fiber is pre-crushed to a particle size range close to the designed one.

[0066] Test methods for each item:

[0067] (1) Test methods for the aspect ratio of glass fiber and D50 particle size of glass flakes in the high-temperature resistant polyester composition:

[0068] Aspect ratio of glass fiber: Weigh 100 g of the material sample, ablate it at 800 °C for 1 h and then cool it to obtain the glass fiber in the material. Disperse the obtained glass fiber evenly in 200 ml of water, pour 10 ml of the suspension of the dispersed glass fiber into a petri dish, select several regions using a microscope, project the glass fiber regions onto the screen, collect pictures, test the lengths of the glass fibers in the pictures to make a normal distribution graph, and the value corresponding to the median in the normal distribution graph is used as the retention length of the glass fiber. The ratio of the retention length of the glass fiber to the diameter of the glass fiber (or the long axis diameter of the flat glass fiber) is used as the aspect ratio of the glass fiber.

[0069] D50 particle size of glass flakes: Weigh 100 g of the material sample, ablate it at 800 °C for 1 h and then cool it to obtain the glass flakes in the material. Disperse the obtained glass flakes evenly in 200 ml of water, and use a laser particle size analyzer of Malvern Panalytical to test the particle size, and obtain the D50 particle size of the glass flakes in the test results.

[0070] (2) Light transmittance: Use an SGW-820 (WGT-2S) light transmittance meter. A test piece with a length of 60 mm, a width of 60 mm, and a thickness of 1 mm prepared by injection molding is used to test the light transmittance of the sample under A light source (2856K).

[0071] (3) Reflectance: Measure using a Color Eye 7000A color difference meter. A test piece with a length of 60 mm, a width of 60 mm, and a thickness of 1 mm prepared by injection molding with a mold temperature of 60 °C. The reflectance at 460 nm is used as the representative value to evaluate the reflectance.

[0072] Table 1: Component contents (parts by weight) and test results of polyester compositions in Examples 1 - 7

[0073]

[0074]

[0075] As can be seen from Examples 2 / 4 - 6, the light diffusing agents containing the structure of the present invention can all significantly improve the light reflectivity, and the polyester composition also has a relatively high light transmittance.

[0076] Table 2: Component contents (parts by weight) and test results of polyester compositions in Examples 8 - 15

[0077]

[0078] As can be seen from Examples 2 / 7 - 9, when the content of the light diffusing agent is preferably 0.0005 - 0.001 times the weight content of the PCT resin, both the light transmittance and the reflectivity are relatively high.

[0079] Continued Table 2:

[0080]

[0081]

[0082] As can be seen from Examples 2 / 10 - 15, with the increase of the aspect ratio, the light transmittance increases but the reflectivity decreases. In order to prepare an SMD type LED reflection bracket, the preferred aspect ratio of the circular glass fiber is 5 - 300, and more preferably 15 - 200.

[0083] Table 3: Component contents (parts by weight) and test results of polyester compositions in Examples 16 - 25

[0084]

[0085] As can be seen from Examples 16 - 19, the preferred flatness ratio of the flat glass fiber is 4 - 6, and both the light transmittance and the reflectivity are higher.

[0086] Continued Table 3:

[0087]

[0088] As can be seen from Examples 16 / 20 - 25, with the increase of the aspect ratio, the light transmittance increases but the reflectivity decreases. In order to prepare an SMD type LED reflection bracket, the preferred aspect ratio of the circular glass fiber is 1 - 200, and more preferably 3 - 100.

[0089] Table 4: Component contents (parts by weight) and test results of polyester compositions in Examples 26 - 31

[0090]

[0091] As can be seen from Examples 26-31, as the D50 particle size of the glass flakes increases, the light transmittance increases but the reflectivity decreases. The D50 particle size is preferably 10-200 μm, more preferably 20-160 μm.

[0092] Table 5: Component contents (parts by weight) and test results of the comparative polyester compositions

[0093]

[0094]

[0095] As can be seen from Example 2 and Comparative Example 1, traditional light diffusing agents cannot achieve the effects of high light transmittance and high reflectivity.

[0096] As can be seen from Comparative Examples 2 / 3 / 4, if the content of the light diffusing agent is too low, not only is the reflectivity low, but the light transmittance is also insufficient; if the content of the light diffusing agent is too high, the light transmittance is too low.

[0097] As can be seen from Comparative Example 5, although titanium dioxide can significantly improve the reflectivity, it will also seriously reduce the light transmittance.

Claims

1. A polyester composition, characterized in that, By weight, it includes the following components: 50-80 parts of PCT resin; 8-40 parts of filler; Light diffuser 0.01-0.1 part; The filler is selected from at least one of flat glass fiber, round glass fiber and glass flakes; The structure of the light diffuser is , wherein R2, R3, R4, and R5 are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an aryl group having 1 to 9 carbon atoms, a halogen atom, a heterocyclic group having 1 to 6 carbon atoms, an ester group having 1 to 6 carbon atoms, or a cyano group; R1 is one of , , , , , , .

2. The polyester composition according to claim 1, characterized in that, R1 is one of , , .

3. The polyester composition according to claim 1, characterized in that, The weight content of the light diffusing agent is 0.0005-0.001 times the weight content of the PCT resin.

4. The polyester composition according to claim 1, wherein In the polyester composition, the aspect ratio of the flat glass fiber is in the range of 0.3-228, and the flatness ratio of the cross section of the flat glass fiber is in the range of 2-7.

5. The polyester composition according to claim 4, characterized in that, In the polyester composition, the aspect ratio of the flat glass fiber is in the range of 1-200.

6. The polyester composition according to claim 4, wherein In the polyester composition, the aspect ratio of the flat glass fiber is in the range of 3-100.

7. The polyester composition according to claim 4, characterized in that, The flatness ratio of the flat glass fiber cross section is 4-6.

8. The polyester composition according to claim 1, characterized in that, In the polyester composition, the aspect ratio of the round glass fiber is in the range of 2-352.

9. The polyester composition according to claim 1, wherein In the polyester composition, the aspect ratio of the round glass fiber is in the range of 5-300.

10. The polyester composition according to claim 1, wherein In the polyester composition, the aspect ratio of the round glass fiber is in the range of 15-200.

11. The polyester composition according to claim 1, characterized in that, In the polyester composition, the D50 particle size range of the glass flakes is 5-250 microns.

12. The polyester composition according to claim 1, characterized in that In the polyester composition, the D50 particle size range of the glass flakes is 10-200 microns.

13. The polyester composition according to claim 1, characterized in that, In the polyester composition, the D50 particle size range of the glass flakes is 20-160 microns.

14. The polyester composition according to claim 1, characterized in that, The melting point of the PCT resin measured by differential scanning calorimetry at a heating and cooling rate of 20°C / min is 260-300°C.

15. The polyester composition according to claim 1, wherein By weight, the invention further comprises 0-2 parts of auxiliary agent, wherein the auxiliary agent is selected from at least one of an antioxidant and a lubricant.

16. A method for preparing the polyester composition according to any one of claims 1 to 15, characterized in that, The invention comprises the following components: polyester resin, filler and light diffuser are mixed according to a proportion, the mixture is melt-blended and extruded into granules through an extruder to obtain a high-temperature resistant polyester composition; wherein the heating temperatures of the extruder are as follows: 250-290°C for zone 1, 260-300°C for zones 2-4, 270-310°C for zones 5-7, 260-300°C for zones 8-9 and 250-290°C for the die.

17. Use of the polyester composition according to any one of claims 1 to 15, characterized in that, Used to prepare SMD type LED reflector bracket.

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