PC material with high light transmittance and high haze and application thereof
Technical Field
The invention relates to the technical field of PC materials, in particular to a PC material with high light transmittance and high haze and application thereof.
Background
At present, energy-saving and environment-friendly lamps are becoming more popular, development of lamp shade materials of LED lamp tubes is receiving more and more attention, and common lamp shade materials of the lamp tubes are PC (polycarbonate), PMMA (acrylic) and the like. PC is thermoplastic engineering plastic with excellent comprehensive performance, has excellent weather resistance, high impact resistance, excellent electric insulation, high light transmittance and less light energy loss, and is widely used in the fields of electric lighting and the like. Therefore, the LED lamp tube lampshade material is biased to select the light diffusion PC resin, which is the development trend in the future.
In the LED lamp, it is required to add a light diffusing agent to the PC resin, because the light transmittance is maintained as much as possible and the light utilization rate is improved without causing glare. The light diffusant has a spherical structure, is uniformly dispersed in the PC resin to form a sea-island structure, and because the refractive indexes of the PC resin and the light diffusant are different, light rays can be reflected on the surface of the light diffusant like a mirror surface, and the light diffusant achieves a light diffusion effect after multiple reflections. The addition amount, the particle size and the distribution of the light diffusant and the refractive index determine the optical performance of the material.
The invention patent of CN108276750 discloses a light diffusion composition with a core-shell structure, the light diffusion effect of which is good, but the applicant finds that the light transmittance of microcrystalline cellulose is low, the influence on the light transmittance of the material is large, and the requirement of high light transmittance cannot be met when the microcrystalline cellulose is used in a PC material.
Disclosure of Invention
In order to overcome the defects and shortcomings in the prior art, the invention aims to provide a PC material with high light transmittance and high haze and application thereof.
The purpose of the invention is realized by the following technical scheme:
a PC material with high light transmittance and high haze comprises the following raw materials in parts by weight:
the special light diffusant is prepared by the following steps:
(1) adding 80-100 parts by weight of methyl methacrylate, 10-20 parts by weight of methyl acrylate, 40-50 parts by weight of nano silicon dioxide and 0.2-0.4 part by weight of n-dodecyl mercaptan into 100 parts by weight of organic solvent, adding 0.1-0.3 part by weight of first initiator in the stirring process, and then reacting for 1-3 hours at 40-50 ℃ to obtain a pre-polymerization solution;
(2) adding 40-60 parts by weight of acrylonitrile and 5-10 parts by weight of methyl acrylate into the prepolymerization liquid, adding 0.1-0.3 part by weight of a second initiator in the stirring process, and then reacting for 2-4h at 40-50 ℃ to obtain polymer liquid;
(3) and (3) carrying out electrostatic spraying on the polymer liquid to obtain the special light diffusant.
The light diffusion agent is a three-layer structure microsphere of nano silicon dioxide-polymethyl methacrylate-polyacrylonitrile, and the particle size is 30-50 mu m.
Polymethyl methacrylate (PMMA) is a plastic with high light transmittance, and is usually blended and modified with PC to manufacture optical products, but the refractive indexes of the PMMA and the PC are both about 1.5, so that polymethyl methacrylate is basically not used as a light diffusion modification material. However, the refractive index of polyacrylonitrile copolymerized by acrylonitrile and methyl acrylate is about 1.4, so that polymethyl methacrylate also has a certain light diffusion effect through secondary refraction, and the nano silicon dioxide serving as a core is used as an inorganic light diffusing agent to play a strong refraction effect, so that the PC haze is obviously improved; the three-layer structure of the nano-silica-polymethyl methacrylate-polyacrylonitrile also reduces the dosage of the nano-silica, so that the influence on the light transmittance of PC is small; in addition, the polyacrylonitrile with a higher melting point is used as the shell, so that the structural stability of the microsphere can be maintained in the melt extrusion process, and the batch quality of the product is more stable.
Wherein the organic solvent is one of toluene, xylene and ethyl acetate.
Wherein the first initiator and the second initiator are both azobisisobutyronitrile.
Wherein the particle size of the nano silicon dioxide is 10-20 nm.
Wherein the spraying voltage of the electrostatic spraying is 20-30kV, and the spraying temperature is 20-30 ℃.
Wherein the antioxidant is antioxidant 168 and/or antioxidant 1076.
Wherein the light stabilizer is bis (1, 2,2,6, 6-pentamethyl-4-piperidyl) sebacate and/or poly (1-hydroxyethyl-2, 2,6, 6-tetramethyl-4-hydroxypiperidine) succinate.
Wherein the ultraviolet absorbent is 2-cyano-3, 3' -diphenylacrylic acid-2-ethylhexyl ester and/or 2- (2-hydroxy-3-tert-butyl-5-methylphenyl) -5-chlorobenzotriazole.
The PC material with high light transmittance and high haze is prepared by the following method: all the raw materials are put into a double-screw extruder for extrusion granulation, and the melting temperature is 200-250 ℃.
The application of the PC material with high light transmittance and high haze is applied to the manufacturing of LED lamps.
The invention has the beneficial effects that: the refractive index of polyacrylonitrile copolymerized by acrylonitrile and methyl acrylate is about 1.4, so that polymethyl methacrylate also has a certain light diffusion effect through secondary refraction, and the nano silicon dioxide serving as a core is used as an inorganic light diffusing agent to play a strong refraction effect, so that the PC haze is remarkably improved; the three-layer structure of the nano-silica-polymethyl methacrylate-polyacrylonitrile also reduces the dosage of the nano-silica, so that the influence on the light transmittance of PC is small; in addition, the polyacrylonitrile with a higher melting point is used as the shell, so that the structural stability of the microsphere can be maintained in the melt extrusion process, and the batch quality of the product is more stable.
Detailed Description
The present invention will be further described with reference to the following examples for facilitating understanding of those skilled in the art, and the description of the embodiments is not intended to limit the present invention.
Example 1
A PC material with high light transmittance and high haze comprises the following raw materials in parts by weight:
the special light diffusant is prepared by the following steps:
(1) adding 80 parts by weight of methyl methacrylate, 10 parts by weight of methyl acrylate, 40 parts by weight of nano-silica and 0.2 part by weight of n-dodecyl mercaptan into 100 parts by weight of organic solvent, adding 0.1 part by weight of first initiator in the stirring process, and then reacting for 1 hour at 40 ℃ to obtain a pre-polymerization solution;
(2) adding 40 parts by weight of acrylonitrile and 5 parts by weight of methyl acrylate into the prepolymerization liquid, adding 0.1 part by weight of a second initiator in the stirring process, and then reacting for 2 hours at 40 ℃ to obtain polymer liquid;
(3) and (3) carrying out electrostatic spraying on the polymer liquid to obtain the special light diffusant.
Wherein the organic solvent is toluene.
Wherein the first initiator and the second initiator are both azobisisobutyronitrile.
Wherein the particle size of the nano silicon dioxide is 10 nm.
Wherein the spraying voltage of the electrostatic spraying is 20kV, and the spraying temperature is 20 ℃.
Wherein the antioxidant is antioxidant 168.
Wherein the light stabilizer is bis (1, 2,2,6, 6-pentamethyl-4-piperidyl) sebacate.
Wherein the ultraviolet absorbent is 2-cyano-3, 3' -diphenylacrylic acid-2-ethylhexyl ester.
Example 2
A PC material with high light transmittance and high haze comprises the following raw materials in parts by weight:
the special light diffusant is prepared by the following steps:
(1) adding 100 parts by weight of methyl methacrylate, 20 parts by weight of methyl acrylate, 50 parts by weight of nano-silica and 0.4 part by weight of n-dodecyl mercaptan into 100 parts by weight of organic solvent, adding 0.3 part by weight of first initiator in the stirring process, and then reacting for 3 hours at 50 ℃ to obtain a pre-polymerization solution;
(2) adding 60 parts by weight of acrylonitrile and 10 parts by weight of methyl acrylate into the prepolymerization liquid, adding 0.3 part by weight of a second initiator in the stirring process, and then reacting for 4 hours at 50 ℃ to obtain polymer liquid;
(3) and (3) carrying out electrostatic spraying on the polymer liquid to obtain the special light diffusant.
Wherein the organic solvent is ethyl acetate.
Wherein the first initiator and the second initiator are both azobisisobutyronitrile.
Wherein the particle size of the nano silicon dioxide is 20 nm.
Wherein the spraying voltage of the electrostatic spraying is 30kV, and the spraying temperature is 30 ℃.
Wherein the antioxidant is an antioxidant 1076.
Wherein the light stabilizer is poly (1-hydroxyethyl-2, 2,6, 6-tetramethyl-4-hydroxypiperidine) succinate.
Wherein the ultraviolet absorbent is 2- (2-hydroxy-3 tert-butyl-5-methylphenyl) -5-chlorobenzotriazole.
Example 3
A PC material with high light transmittance and high haze comprises the following raw materials in parts by weight:
the special light diffusant is prepared by the following steps:
(1) adding 90 parts by weight of methyl methacrylate, 15 parts by weight of methyl acrylate, 45 parts by weight of nano-silica and 0.3 part by weight of n-dodecyl mercaptan into 100 parts by weight of organic solvent, adding 0.2 part by weight of first initiator in the stirring process, and then reacting for 2 hours at 45 ℃ to obtain a pre-polymerization solution;
(2) adding 50 parts by weight of acrylonitrile and 7.5 parts by weight of methyl acrylate into the prepolymerization liquid, adding 0.2 part by weight of a second initiator during stirring, and then reacting for 3 hours at 45 ℃ to obtain polymer liquid;
(3) and (3) carrying out electrostatic spraying on the polymer liquid to obtain the special light diffusant.
Wherein the organic solvent is xylene.
Wherein the first initiator and the second initiator are both azobisisobutyronitrile.
Wherein the particle size of the nano silicon dioxide is 15 nm.
Wherein the spraying voltage of the electrostatic spraying is 25kV, and the spraying temperature is 25 ℃.
Wherein the antioxidant is prepared from antioxidant 168 and antioxidant 1076 according to a weight ratio of 1: 1 in a certain proportion.
Wherein the light stabilizer is prepared from bis (1, 2,2,6, 6-pentamethyl-4-piperidyl) sebacate and poly (1-hydroxyethyl-2, 2,6, 6-tetramethyl-4-hydroxypiperidine) succinate according to the weight ratio of 1: 1 in a certain proportion.
Wherein the ultraviolet absorbent is prepared from 2-cyano-3, 3' -diphenylacrylic acid-2-ethylhexyl ester and 2- (2-hydroxy-3-tert-butyl-5-methylphenyl) -5-chlorobenzotriazole according to the weight ratio of 1: 1 in a certain proportion.
Comparative example 1
This comparative example differs from example 3 in that:
the special light diffusant is replaced by nano silicon dioxide with equal mass.
Comparative example 2
This comparative example differs from example 3 in that:
the special light diffusant is prepared by the following steps:
(1) adding 90 parts by weight of methyl methacrylate, 15 parts by weight of methyl acrylate, 45 parts by weight of nano silicon dioxide and 0.3 part by weight of n-dodecyl mercaptan into 100 parts by weight of organic solvent, adding 0.2 part by weight of azobisisobutyronitrile during stirring, and then reacting for 3 hours at 45 ℃ to obtain a pre-polymerization solution;
(2) and (3) carrying out electrostatic spraying on the polymer liquid to obtain the special light diffusant.
Comparative example 3
This comparative example differs from example 3 in that:
the special light diffusant is prepared by the following steps:
(1) adding 90 parts by weight of methyl methacrylate, 15 parts by weight of methyl acrylate and 0.3 part by weight of n-dodecyl mercaptan into 100 parts by weight of organic solvent, adding 0.2 part by weight of first initiator in the stirring process, and then reacting for 2 hours at 45 ℃ to obtain a pre-polymerization solution;
(2) adding 50 parts by weight of acrylonitrile and 7.5 parts by weight of methyl acrylate into the prepolymerization liquid, adding 0.2 part by weight of a second initiator during stirring, and then reacting for 3 hours at 45 ℃ to obtain polymer liquid;
(3) and (3) carrying out electrostatic spraying on the polymer liquid to obtain the special light diffusant.
The PC materials of example 3 and comparative examples 1-3 were tested for light transmittance and haze using ASTM D638, ASTM D790, ASTM D256, ASTM D1003, respectively, and the results are given in the following table:
as can be seen from comparative example 1, the influence of nano-silica as an opaque substance on light transmittance is the largest, and haze is not more than that of example 3 due to the decrease of light transmittance; from comparative example 2, it can be seen that only polymethyl methacrylate is used to coat nano-silica, and the relative dosage of nano-silica is increased, so that the light transmittance is slightly reduced, and meanwhile, polymethyl methacrylate alone has no light diffusion effect, so the haze is also low; it can be seen from comparative example 3 that the microsphere without the nano-silica core has very good light transmittance, and the light transmittance of PC reaches the highest, but the light diffusion effect of the nano-silica is lost, and the improvement effect on the haze is very limited.
The above-described embodiments are preferred implementations of the present invention, and the present invention may be implemented in other ways without departing from the spirit of the present invention.