CN104945878A - Preparation method of high-light-transmittance high-thermal-conductivity LED (light-emitting diode) lens - Google Patents

Abstract

The invention relates to a preparation method of a high-light-transmittance high-thermal-conductivity LED (light-emitting diode) lens, which comprises the following steps: nano graphene surface modification, resin drying, mixing, extrusion granulation, injection molding and heat treatment. The nano graphene for modifying the traditional resin LED lens material can effectively enhance the light transmittance and thermal conductivity. When being applied to LEDs, the lens prepared from the modified resin can widen the application range of LEDs, and has longer service life. Compared with the preparation process of the traditional resin LED lens, the preparation technique of the high-light-transmittance high-thermal-conductivity LED lens does not have special requirements, and can perform production by using the original processing equipment.

Description

A kind of preparation method of LED lens with high light transmittance and high thermal conductivity

technical field

The invention belongs to the lighting field and relates to a method for preparing an LED lens with high light transmittance and high thermal conductivity.

Background technique

LED (Light Emitting Diode) is a kind of electroluminescent solid-state device, which can directly convert electrical energy into light energy. Due to the advantages of high luminous efficiency, long service life, energy saving and environmental protection, etc., it has gradually replaced traditional incandescent lamps, tungsten halogen lamps, fluorescent tubes and cold cathode fluorescent lamps in recent years, and has been widely used in the field of lighting and LCD backlight. Applications. The LED lens is an optical system that is closely connected with the LED to help improve the light output efficiency of the LED and change the light field distribution of the LED, and is placed close to the LED. The resin material used to prepare the LED lens is mainly polycarbonate (PC) or polymethyl methacrylate (PMMA), and the LED lens is made by injection molding.

PC and PMMA are organic polymer materials with poor thermal conductivity and heat resistance. They are made of LED lenses that are used for a long time or used in high-power LEDs. Under the continuous action of the light source, heat will accumulate in the material so that it can be used The temperature keeps rising. When the temperature rises to a certain level, PC and PMMA will deform and turn yellow, which will eventually affect the light transmittance and service life of the LED lens.

Research on improving the thermal conductivity of PC and PMMA transparent materials, especially the use of nano-graphene to improve the thermal conductivity of its use as LED lens materials has not been reported.

At the same time, there is a strong intermolecular force between graphene layers, and the layers are easy to stack together, and it is difficult to mix with organic polymer materials. Therefore, graphene must be surface-modified to improve its uniform dispersion in PC or PMMA.

Therefore, it is necessary to explore a reasonable modification method to improve the thermal conductivity of PC and PMMA, avoid material structural deformation and yellowing, and moderately increase its light transmittance. Using it to prepare LED lenses can broaden the application field of the lens and prolong its service life.

Contents of the invention

The technical problem to be solved by the present invention is: based on the above problems, the present invention provides a method for preparing an LED lens with high light transmittance and high thermal conductivity.

A technical solution adopted by the present invention to solve the technical problem is: a method for preparing a LED lens with high light transmittance and high thermal conductivity, comprising the following steps:

(1) Surface modification of graphene nanometers: surface modification of graphene nanometers with surface modifiers by means of ultrasonic modification;

(2) Resin drying: control the moisture content of PC or PMMA to 0-0.03%;

(3) Mixing: the surface-modified nano-graphene and dry PC or PMMA powder are placed in a high-speed mixer for initial mixing;

(4) Extrusion granulation: the initial mixture that step (3) obtains is extruded granulation with a twin-screw extruder;

(5) Injection molding: injection molding of the pellets obtained in step (4) with a precision injection machine;

(6) Heat treatment: heat-treat the injection molded product obtained in step (5).

Further, in the step (1), the surface modifier of graphene nanometer is one or more of coupling agent, oleic acid or cationic surfactant, and the total amount of surface modifier is 2-20wt% of graphene nanometer.

Further, the coupling agent is one or both of silane coupling agent or titanate coupling agent, and the cationic surfactant is cetyltrimethylammonium bromide, cetylpyridinium bromide or One or more of 2-alkyl imidazolines.

Further, the ultrasonic modification method in step (1) is to dissolve the surface modification agent in absolute ethanol, add nano-graphene, and place it in an ultrasonic cleaning machine for ultrasonic modification, with a power of 40-500W, a frequency of 50-200Hz, and a time of 20min～2h.

Further, in step (2), the optical-grade PC is dried at 110-120°C for 12-24 hours, and the optical-grade PMMA is dried at 80-85°C for 4-5 hours.

Further, in step (3), the content of surface-modified graphene nanometers in the mixture is 1-25wt% of PC or PMMA, the speed of the high-speed mixer is 300-500r/min, and the mixing time is 5-10min.

Further, in the step (4), the extrusion granulation temperature of the PC material is 250-270°C, and the screw speed is 50-80r/min; the extrusion granulation temperature of the PMMA material is 150-230°C, and the screw speed is 20-80r/min. 30r/min.

Further, the injection temperature of PC material in step (5) is 250-320°C, the injection pressure is 60-120MPa, and the mold temperature is 80-120°C; the injection temperature of PMMA material is 180-240°C, and the injection pressure is 80-120°C. 130MPa, the mold temperature is 40-80°C.

Further, in step (6), the PC product is treated at 100-135°C for 0.5-8 hours, and the PMMA product is treated at 70-80°C for 3-6 hours; the heat treatment of the PC injection molded product can be processed continuously at the same temperature section, or Continuous processing in different temperature sections.

The beneficial effects of the present invention are: the use of nano-graphene to modify the traditional resin LED lens material can effectively improve its light transmittance and thermal conductivity; the lens prepared by the modified resin is applied to the LED, which can broaden the application field of the LED. At the same time, the service life of the LED lens can be extended; the preparation process of the high light transmittance and high thermal conductivity LED lens has no special requirements compared with the preparation of the traditional resin LED lens, and can be produced by the original processing equipment.

Detailed ways

The present invention will now be further described in conjunction with specific examples, and the following examples are intended to illustrate the present invention rather than further limit the present invention.

Example 1

The silane coupling agent KH560, the oleic acid of 1wt% and the hexadecyltrimethylammonium bromide of 1.5wt% are dissolved in dehydrated alcohol with respect to the nano graphene total amount 2wt%, add a certain amount of nano graphene , placed in an ultrasonic cleaning machine, set the frequency at 60 Hz, and the power at 80 W, ultrasonically treated for 1 hour, and dried. After drying the optical-grade PC powder at 120° C. for 12 hours with hot air under normal pressure, it was mixed with 5 wt % surface-modified nano-graphene for 8 minutes at high speed in a high-speed mixer, and the rotor speed of the high-speed mixer was set at 500 r/min. The mixture is extruded and granulated with a twin-screw extruder, the extrusion temperature is 250-265°C, and the screw speed is 60r/min. The modified pellets are injection molded, the injection temperature is 280-300°C, the injection pressure is 80MPa, and the mold temperature is 100°C. The injection molded sample is placed in a hot air circulation drying oven and heated to 100-105°C for 20 minutes, then heated to 120-125°C for 30 minutes, and cooled to room temperature together with the drying oven. Compared with the unmodified PC material, the performance of the above-mentioned PC material modified with surface-modified nano-graphene is shown in the following table:

Example 2

The silane coupling agent KH560, the oleic acid of 1wt% and the hexadecyltrimethylammonium bromide of 1.5wt% are dissolved in dehydrated alcohol with respect to the nano graphene total amount 2wt%, add a certain amount of nano graphene , placed in an ultrasonic cleaning machine, set the frequency at 60 Hz, and the power at 80 W, ultrasonically treated for 1 hour, and dried. After drying the optical grade PMMA powder at 85°C with hot air under normal pressure for 5 hours, it was mixed with 5wt% surface-modified nano-graphene for 5 minutes at high speed with a high-speed mixer, and the rotor speed of the high-speed mixer was set at 500r/min. The mixture is extruded and granulated by a twin-screw extruder, the extrusion temperature is 170-200°C, and the screw speed is 30r/min. The modified pellets are injection molded, the injection temperature is 190-220°C, the injection pressure is 100MPa, and the mold temperature is 60°C. The injection molded samples were placed in a hot air circulation drying oven and heated to 75-80°C for 6 hours, and then cooled to room temperature together with the drying oven. The above-mentioned PMMA material modified with surface-modified nano-graphene is compared with the unmodified PMMA material, and its performance is shown in the following table:

Inspired by the above-mentioned ideal embodiment according to the present invention, through the above-mentioned description content, relevant workers can make various changes and modifications within the scope of not departing from the technical idea of the present invention. The technical scope of the present invention is not limited to the content in the specification, but must be determined according to the scope of the claims.

Claims (9)

1. a preparation method for the LED lens of high transmission rate, high thermal conductivity, is characterized in that: comprise the following steps:

(1) nano-graphene finishing: utilize coating materials to carry out finishing to nano-graphene by the method for ultrasonic modification;

(2) resin drying: control PC or PMMA water ratio are 0 ~ 0.03%;

(3) batch mixing: nano-graphene and dry PC or the PMMA powder of surface modification are placed in high-speed mixer and just mix;

(4) extruding pelletization: the first batch mixing twin screw extruder extruding pelletization that step (3) is obtained;

(5) injection moulding: the pellet precise injection machine injection moulding that step (4) is obtained;

(6) thermal treatment: the injection-molded item thermal treatment that step (5) is obtained.

2. the preparation method of the LED lens of a kind of high transmission rate according to claim 1, high thermal conductivity, it is characterized in that: in described step (1), the coating materials of nano-graphene is one or more in coupling agent, oleic acid or cats product, and the total consumption of coating materials is 2 ~ 20wt% of nano-graphene.

3. the preparation method of the LED lens of a kind of high transmission rate according to claim 2, high thermal conductivity, it is characterized in that: described coupling agent is one or both in silane coupling agent or titanate coupling agent, and cats product is one or more in cetyl trimethylammonium bromide, cetyl pyridinium bromide or 2-alkyl imidazoline.

4. the preparation method of the LED lens of a kind of high transmission rate according to claim 1, high thermal conductivity, it is characterized in that: in described step (1), ultrasonic modifying method is for be dissolved in dehydrated alcohol by coating materials, add nano-graphene, be placed in the ultrasonic modification of Ultrasonic Cleaners, power is 40 ~ 500W, frequency is 50 ~ 200Hz, and the time is 20min ~ 2h.

5. the preparation method of the LED lens of a kind of high transmission rate according to claim 1, high thermal conductivity, it is characterized in that: in described step (2), optical grade PC was 110 ~ 120 DEG C of dryings 12 ~ 24 hours, and optical grade PMMA was 80 ~ 85 DEG C of dryings 4 ~ 5 hours.

6. the preparation method of the LED lens of a kind of high transmission rate according to claim 1, high thermal conductivity, it is characterized in that: in described step (3), in compound, the nano-graphene content of surface modification is the 1 ~ 25wt% of PC or PMMA, high-speed mixer rotating speed 300 ~ 500r/min, mixing time 5 ~ 10min.

7. the preparation method of the LED lens of a kind of high transmission rate according to claim 1, high thermal conductivity, is characterized in that: in described step (4), the extruding pelletization temperature of PC material is 250 ~ 270 DEG C, and screw speed is 50 ~ 80r/min; The extruding pelletization temperature of PMMA material is 150 ~ 230 DEG C, and screw speed is 20 ~ 30r/min.

8. the preparation method of the LED lens of a kind of high transmission rate according to claim 1, high thermal conductivity, it is characterized in that: in described step (5), the injection temperature of PC material is 250 ~ 320 DEG C, injection pressure is 60 ~ 120MPa, and mould temperature is 80 ~ 120 DEG C; The injection temperature of PMMA material is 180 ~ 240 DEG C, and injection pressure is 80 ~ 130MPa, and mould temperature is 40 ~ 80 DEG C.

9. the preparation method of the LED lens of a kind of high transmission rate according to claim 1, high thermal conductivity, it is characterized in that: in described step (6), PC goods process 0.5 ~ 8 hour at 100 ~ 135 DEG C, and PMMA goods process 3 ~ 6 hours at 70 ~ 80 DEG C; The thermal treatment of PC injection-molded item can process continuously in same temperature section, and temperature section also can be divided to process continuously.