PP resin foaming optical diffusion plate and preparation method thereof

Abstract

The invention discloses a PP resin foaming optical diffusion plate and a preparation method thereof.The diffusion plate comprises an upper layer, a middle layer and a lower layer, the upper layer and the lower layer are located on the two sides of the middle layer, the thickness ratio of the upper layer to the middle layer to the lower layer is 1: (7-9): 1, and the upper layer and the lower layer are the same in composition; the upper layer is prepared from the following components in parts by mass: PP resin, PP-g-MAH resin, copolymer microspheres, a flame retardant, an antioxidant, mineral oil, a light stabilizer, an ultraviolet light absorber and a whitening agent; the middle layer is prepared from the following components in parts by mass: GPPS resin, a foaming agent, an antioxidant, mineral oil, a light stabilizer, an ultraviolet light absorber and a whitening agent, and the diffusion plate is stable in overall structure, good in optical performance and low in manufacturing cost.

Description

Technical Field

[0001] The invention relates to the technical field of optical diffusion plate manufacturing, in particular to a PP resin foamed optical diffusion plate and a preparation method thereof. Background Art

[0002] Light diffuser, also known as light homogenizer, has been widely used in the field of liquid crystal display and LED lighting. Its main function is to fully scatter the incident light to achieve a softer and more uniform illumination effect. However, the existing GPPS material used to manufacture optical diffuser generally has poor heat resistance and impact resistance. After long-term use, the heat of the light source can easily cause the diffuser to deform, affecting its service life. During transportation, it is easy to be damaged by impact, resulting in defects.

[0003] Polypropylene (PP) is a general-purpose thermoplastic obtained by polymerization of propylene. Due to its abundant raw material sources and simple synthesis process, compared with other general-purpose thermoplastics, it has the characteristics of low price, strong impact resistance, good heat and chemical resistance, high mechanical strength, etc., and is therefore widely used in the automotive, electrical, packaging and daily necessities industries. Patent document CN220320523U discloses a corrosion-resistant polypropylene PP tube, and patent document CN213200686U discloses a PP polypropylene environmentally friendly recycled woven bag, but there is no relevant report on a PP resin foamed optical diffuser plate. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a PP resin foamed optical diffuser with stable overall structure, good optical performance and low manufacturing cost, comprising an upper layer, a middle layer and a lower layer, wherein the upper layer and the lower layer are located on both sides of the middle layer, the thickness ratio of the upper layer, the middle layer and the lower layer is 1:(7-9):1, the upper layer and the lower layer have the same components, and the upper layer comprises the following components in terms of mass fractions: 69-85 parts of PP resin, 10-20 parts of PP-g-MAH resin, 1-3 parts of copolymer microspheres, 3-5 parts of flame retardant, 0. 3 to 0.7 parts of antioxidant, 0.08 to 0.16 parts of mineral oil, 0.4 to 1.2 parts of light stabilizer, 0.2 to 0.9 parts of ultraviolet absorber, and 0.02 to 0.04 parts of brightener; the middle layer includes the following components in parts by mass: 83 to 93 parts of GPPS resin, 5 to 13 parts of foaming agent, 0.4 to 1.2 parts of antioxidant, 0.23 to 0.27 parts of mineral oil, 0.6 to 1 parts of light stabilizer, 0.4 to 1.1 parts of ultraviolet absorber, and 0.37 to 0.43 parts of brightener.

[0005] Preferably, the antioxidant is at least one of antioxidant 1024, antioxidant 1010 or antioxidant 1076.

[0006] Preferably, the mineral oil is silicone oil or liquid paraffin.

[0007] Preferably, the light stabilizer is any one or more selected from light stabilizer 622, light stabilizer 770, and light stabilizer 944.

[0008] Preferably, the ultraviolet absorber is selected from one or more of the ultraviolet absorbers UV-327, UV-329, and UV-531.

[0009] Preferably, the brightener is fluorescent brightener CBS-127.

[0010] The present invention also provides a method for preparing a PP resin foamed optical diffusion plate, comprising the following steps:

[0011] preparing copolymer microspheres;

[0012] 1 to 3 parts of copolymer microspheres, 69 to 85 parts of PP resin, 10 to 20 parts of PP-g-MAH resin, 3 to 5 parts of flame retardant, 0.3 to 0.7 parts of antioxidant, 0.08 to 0.16 parts of mineral oil, 0.4 to 1.2 parts of light stabilizer, 0.2 to 0.9 parts of ultraviolet absorber, and 0.02 to 0.04 parts of brightener are uniformly mixed to obtain a mixture a;

[0013] 83-93 parts of GPPS resin, 5-13 parts of foaming agent, 0.4-1.2 parts of antioxidant, 0.23-0.27 parts of mineral oil, 0.6-1 parts of light stabilizer, 0.4-1.1 parts of ultraviolet absorber, and 0.37-0.43 parts of brightener are uniformly mixed to obtain a mixture b;

[0014] Mixture a and mixture b are put into a single screw extruder in a mass ratio of 2:(3-5), heated and melted, three-layer co-extruded and embossed to obtain a finished product;

[0015] Among them, the temperatures of each zone of the single-screw extruder are: zone one temperature is 180-190°C, zone two temperature is 190-200°C, zone three temperature is 210-220°C, zone four temperature is 210-220°C, zone five temperature is 225-235°C, zone six temperature is 215-225°C, zone seven temperature is 210-220°C, and the die head temperature is 205-215°C; the production speed is 310kg / h.

[0016] Preferably, the preparation of copolymer microspheres comprises the following steps:

[0017] 30-50 parts of maleic anhydride, 45-55 parts of styrene and 5-15 parts of azobisisobutyronitrile are respectively dissolved in 150-250 parts of isoamyl acetate, and nitrogen is passed through for 30-40 minutes, and then heated in a water bath at 70°C for 4-6 hours; the suspension after the reaction is centrifuged, the supernatant is removed, the solid is dispersed in n-hexane for washing, the filter residue is collected by filtration, and the filter residue is dried to obtain copolymer microspheres.

[0018] Preferably, the centrifugal speed is 2000-4000 r / min, and the centrifugal time is 20-30 min.

[0019] Preferably, the drying temperature is 90-110° C. and the drying time is 6-8 hours.

[0020] The beneficial effects are as follows: the present application provides a PP resin foamed optical diffuser, comprising three layers, an upper layer, a middle layer and a lower layer. The middle layer uses GPPS resin as a substrate. Since the GPPS resin has high transparency and is combined with a brightener, the middle layer can have a high light transmittance. Secondly, the addition of a foaming agent to the middle layer can form a microporous structure in the middle layer so as to evenly and effectively scatter light. Secondly, this microporous structure can also significantly reduce the weight of the middle layer. The upper and lower layers use PP resin with good mechanical properties and chemical resistance as a substrate, which can make the diffuser as a whole more weather-resistant and aging-resistant, and provide better protection and support for the middle layer.

[0021] And because GPPS resin is an amorphous thermoplastic and PP resin is a semi-crystalline thermoplastic, the two have great differences in molecular chain structure, polarity and crystallization behavior, resulting in poor compatibility between GPPS resin and PP resin, and direct mixing is prone to stratification. Therefore, solving the compatibility and interface adhesion between GPPS resin and PP resin is the key to preparing the optical diffuser plate. The inventors have made a lot of attempts and finally found that adding PP-g-MAH resin to the system can significantly improve the compatibility and interface adhesion between the upper and lower layers and the middle layer. This is because the maleic anhydride group in the PP-g-MAH resin can react with the benzene ring in GPPS to improve the interface bonding force between the upper and lower layers and the middle layer, thereby improving the overall structural stability of the diffuser plate.

[0022] In addition, the upper and lower layers are added with self-developed copolymer microspheres to further improve the light diffusion effect of the upper and lower layers. This copolymer microsphere has good compatibility with PP resin, so it can form good dispersion in PP resin. The refractive index of the copolymer microsphere is 1.4897, which is slightly different from the refractive index of PP resin 1.5076. Using the copolymer microsphere as a light diffuser can significantly improve the haze and transmittance of the upper and lower layers.

[0023] Finally, the present application designs the thickness ratio of the upper, middle and lower layers to be 1:(7~9):1, which is based on the good light transmittance of the middle layer and the excellent light diffusion function and mechanical strength of the upper and lower layers. In this way, when the thickness ratio of the upper, middle and lower layers is reasonable, it can not only ensure that the diffuser has excellent optical properties, but also ensure the overall structural stability and durability of the diffuser, while also saving manufacturing costs to the greatest extent. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below in conjunction with specific embodiments so that those skilled in the art can understand the present invention more clearly.

[0025] The following embodiments are only used to illustrate the present invention, but are not limited to the scope of the present invention. Based on the specific embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work belong to the protection scope of the present invention.

[0026] In the examples of the present invention, unless otherwise specified, all raw material components are commercially available products well known to those skilled in the art; in the examples of the present invention, unless otherwise specified, the technical means used are conventional means well known to those skilled in the art.

[0027] Source of raw materials:

[0028] Polystyrene (GPPS) resin, model GPPS-300NT, was purchased from PetroChina Dushanzi Petrochemical Company;

[0029] Polypropylene (PP), model M60ET, was purchased from Zhenhai Refining and Chemical Company of Sinopec;

[0030] Polypropylene grafted maleic anhydride (PP-g-MAH) resin, model Mitsui ADMER, Japan, purchased from Jiangsu Weirun High Plastic Chemical Co., Ltd.;

[0031] Flame retardant (melamine), purchased from Yunsheng Chemical (Shandong) Co., Ltd.;

[0032] Foaming agent (sodium bicarbonate) was purchased from Foshan Sanzhong Environmental Protection Technology Co., Ltd.

[0033] Antioxidants were purchased from Shandong Xuxiang Chemical Co., Ltd.

[0034] Silicone oil was purchased from Jinan Xuchuang Chemical Technology Co., Ltd.

[0035] Liquid paraffin was purchased from Hefeng New Energy Co., Ltd.;

[0036] Light stabilizer, purchased from Shanghai Tiandui New Materials Co., Ltd.;

[0037] Ultraviolet absorber, purchased from Jinan Xiangfeng Weiye Chemical Co., Ltd.;

[0038] Fluorescent brightener, model CBS-127, purchased from Guangzhou Yuanda New Materials Co., Ltd.;

[0039] Maleic anhydride was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0040] Styrene was purchased from Shandong Chuangying Chemical Co., Ltd.;

[0041] Azobisisobutyronitrile was purchased from Zibo Tongyizhai Chemical Co., Ltd.

[0042] Isoamyl acetate was purchased from Xiamen Minghuiyang Chemical Co., Ltd.;

[0043] n-Hexane was purchased from Jinan Mingxin Chemical Co., Ltd.;

[0044] The remaining reagents are commercially available.

[0045] Example 1

[0046] The present embodiment provides a PP resin foamed optical diffuser plate, comprising an upper layer, a middle layer and a lower layer, wherein the upper layer and the lower layer are located on both sides of the middle layer, the thickness ratio of the upper layer, the middle layer and the lower layer is 1:7:1, the upper layer and the lower layer have the same components, and the upper layer comprises the following components in parts by mass: 85 parts of PP resin, 10 parts of PP-g-MAH resin, 1 part of copolymer microspheres, 3 parts of flame retardant, 0.3 parts of antioxidant, 0.08 parts of mineral oil, 0.4 parts of light stabilizer, 0.2 parts of ultraviolet absorber The intermediate layer includes the following components in parts by mass: 93 parts of GPPS resin, 5 parts of foaming agent, 0.4 parts of antioxidant, 0.23 parts of mineral oil, 0.6 parts of light stabilizer, 0.4 parts of ultraviolet absorber, and 0.37 parts of brightener; among them, the antioxidant is antioxidant 1024; the mineral oil is silicone oil; the light stabilizer is light stabilizer 622; the ultraviolet absorber is ultraviolet absorber UV-327; and the brightener is fluorescent brightener CBS-127.

[0047] The method for preparing the PP resin foamed optical diffusion plate comprises the following steps:

[0048] Preparation of copolymer microspheres: 30 parts of maleic anhydride, 55 parts of styrene and 15 parts of azobisisobutyronitrile are dissolved in 150 parts of isoamyl acetate respectively, nitrogen is passed through for 30 minutes, and then heated in a water bath at 70°C for 4 hours; the suspension after the reaction is centrifuged, the supernatant is removed, the solid is dispersed in n-hexane for washing, the filter residue is collected by filtration, and the filter residue is dried to obtain copolymer microspheres; wherein the centrifugal speed is 2000 r / min, the centrifugal time is 20 minutes, the drying temperature is 90°C, and the drying time is 6 hours;

[0049] 1 part of copolymer microspheres, 85 parts of PP resin, 10 parts of PP-g-MAH resin, 3 parts of flame retardant, 0.3 parts of antioxidant, 0.08 parts of mineral oil, 0.4 parts of light stabilizer, 0.2 parts of ultraviolet absorber, and 0.02 parts of brightener are uniformly mixed to obtain a mixture a;

[0050] 93 parts of GPPS resin, 5 parts of foaming agent, 0.4 parts of antioxidant, 0.23 parts of mineral oil, 0.6 parts of light stabilizer, 0.4 parts of ultraviolet absorber and 0.37 parts of brightener are mixed to obtain a mixture b;

[0051] Mixture a and mixture b are put into a single screw extruder in a mass ratio of 2:3, heated and melted, three-layer co-extruded and embossed to obtain a finished product;

[0052] Among them, the temperatures of each zone of the single-screw extruder are: zone 1 temperature is 180°C, zone 2 temperature is 190°C, zone 3 temperature is 210°C, zone 4 temperature is 210°C, zone 5 temperature is 225°C, zone 6 temperature is 215°C, zone 7 temperature is 210°C, and the die head temperature is 205°C; the production speed is 310kg / h.

[0053] Example 2

[0054] The present embodiment provides a PP resin foamed optical diffuser plate, including an upper layer, a middle layer and a lower layer, wherein the upper layer and the lower layer are located on both sides of the middle layer, the thickness ratio of the upper layer, the middle layer and the lower layer is 1:8:1, the upper layer and the lower layer have the same components, and the upper layer includes the following components by weight: 77 parts of PP resin, 15 parts of PP-g-MAH resin, 2 parts of copolymer microspheres, 4 parts of flame retardant, 0.5 parts of antioxidant, 0.12 parts of mineral oil, 0.8 parts of light stabilizer, 0.55 parts of ultraviolet absorber agent, 0.03 parts of brightener; the middle layer includes the following components in parts by mass: 88 parts of GPPS resin, 9 parts of foaming agent, 0.8 parts of antioxidant, 0.25 parts of mineral oil, 0.8 parts of light stabilizer, 0.75 parts of ultraviolet absorber, 0.4 parts of brightener; among them, the antioxidant is antioxidant 1010; the mineral oil is liquid paraffin; the light stabilizer is light stabilizer 770; the ultraviolet absorber is ultraviolet absorber UV-329; the brightener is fluorescent brightener CBS-127.

[0055] The method for preparing the PP resin foamed optical diffusion plate comprises the following steps:

[0056] Preparation of copolymer microspheres: 40 parts of maleic anhydride, 50 parts of styrene and 10 parts of azobisisobutyronitrile were dissolved in 200 parts of isoamyl acetate respectively, nitrogen was passed for 35 minutes, and then heated in a water bath at 70°C for 5 hours; the suspension after the reaction was centrifuged, the supernatant was removed, the solid was dispersed in n-hexane for washing, the filter residue was collected by filtration, and the filter residue was dried to obtain copolymer microspheres; wherein the centrifugal speed was 3000 r / min, the centrifugal time was 25 minutes, the drying temperature was 100°C, and the drying time was 7 hours;

[0057] 2 parts of copolymer microspheres, 77 parts of PP resin, 15 parts of PP-g-MAH resin, 4 parts of flame retardant, 0.5 parts of antioxidant, 0.12 parts of mineral oil, 0.8 parts of light stabilizer, 0.55 parts of ultraviolet absorber, and 0.03 parts of brightener are uniformly mixed to obtain a mixture a;

[0058] 88 parts of GPPS resin, 9 parts of foaming agent, 0.8 parts of antioxidant, 0.25 parts of mineral oil, 0.8 parts of light stabilizer, 0.75 parts of ultraviolet absorber, and 0.4 parts of brightener are mixed to obtain a mixture b;

[0059] Mixture a and mixture b are put into a single screw extruder in a mass ratio of 2:4, heated and melted, three-layer co-extruded and embossed to obtain a finished product;

[0060] Among them, the temperatures of each zone of the single-screw extruder are: zone 1 temperature is 185°C, zone 2 temperature is 195°C, zone 3 temperature is 215°C, zone 4 temperature is 215°C, zone 5 temperature is 230°C, zone 6 temperature is 220°C, zone 7 temperature is 215°C, and the die head temperature is 210°C; the production speed is 310kg / h.

[0061] Example 3

[0062] A PP resin foamed optical diffuser plate, comprising an upper layer, a middle layer and a lower layer, wherein the upper layer and the lower layer are located on both sides of the middle layer, the thickness ratio of the upper layer, the middle layer and the lower layer is 1:9:1, the upper layer and the lower layer have the same components, and the upper layer comprises the following components by mass: 69 parts of PP resin, 20 parts of PP-g-MAH resin, 3 parts of copolymer microspheres, 5 parts of flame retardant, 0.7 parts of antioxidant, 0.16 parts of mineral oil, 1.2 parts of light stabilizer, 0.9 parts of ultraviolet absorber, 0.04 parts of brightener; the middle layer includes the following components in parts by mass: 83 parts of GPPS resin, 13 parts of foaming agent, 1.2 parts of antioxidant, 0.27 parts of mineral oil, 1 part of light stabilizer, 1.1 parts of ultraviolet absorber, and 0.43 parts of brightener; among them, the antioxidant is antioxidant 1076; the mineral oil is silicone oil; the light stabilizer is light stabilizer 944; the ultraviolet absorber is ultraviolet absorber UV-531; the brightener is fluorescent brightener CBS-127.

[0063] The method for preparing the PP resin foamed optical diffusion plate comprises the following steps:

[0064] Preparation of copolymer microspheres: 50 parts of maleic anhydride, 45 parts of styrene and 5 parts of azobisisobutyronitrile were dissolved in 250 parts of isoamyl acetate respectively, nitrogen was passed for 40 minutes, and then heated in a water bath at 70°C for 6 hours; the suspension after the reaction was centrifuged, the supernatant was removed, the solid was dispersed in n-hexane for washing, the residue was collected by filtration, and the residue was dried to obtain copolymer microspheres; wherein the centrifugal speed was 4000 r / min, the centrifugal time was 30 minutes, the drying temperature was 110°C, and the drying time was 8 hours;

[0065] 3 parts of copolymer microspheres, 69 parts of PP resin, 20 parts of PP-g-MAH resin, 5 parts of flame retardant, 0.7 parts of antioxidant, 0.16 parts of mineral oil, 1.2 parts of light stabilizer, 0.9 parts of ultraviolet absorber, and 0.04 parts of brightener were uniformly mixed to obtain a mixture a;

[0066] 83 parts of GPPS resin, 13 parts of foaming agent, 1.2 parts of antioxidant, 0.27 parts of mineral oil, 1 part of light stabilizer, 1.1 parts of ultraviolet absorber, and 0.43 parts of brightener were mixed to obtain a mixture b;

[0067] Mixture a and mixture b are put into a single screw extruder in a mass ratio of 2:5, heated and melted, three-layer co-extruded and embossed to obtain a finished product;

[0068] Among them, the temperatures of each zone of the single-screw extruder are: zone 1 temperature is 190°C, zone 2 temperature is 200°C, zone 3 temperature is 220°C, zone 4 temperature is 220°C, zone 5 temperature is 235°C, zone 6 temperature is 225°C, zone 7 temperature is 220°C, and the die head temperature is 215°C; the production speed is 310kg / h.

[0069] Comparative Example 1

[0070] The difference between this comparative example and Example 2 is that the PP resin in the upper layer and the lower layer formula is increased from 77 parts to 92 parts, and PP-g-MAH resin is not added. The other ingredients and experimental steps are the same as those in Example 2.

[0071] Comparative Example 2

[0072] The difference between this comparative example and Example 2 is that the PP resin in the upper layer and the lower layer formula is increased from 77 parts to 79 parts, and copolymer microspheres are not added. The other ingredients and experimental steps are the same as those in Example 2.

[0073] Comparative Example 3

[0074] The difference between this comparative example and Example 2 is that in the upper layer and the lower layer formula, 2 parts of silicon dioxide replace 2 parts of copolymer microspheres, and the other ingredients and experimental steps are the same as those in Example 2.

[0075] Comparative Example 4

[0076] The difference between this comparative example and Example 2 is that the GPPS resin in the intermediate layer formula is increased from 88 parts to 95 parts, and the foaming agent is reduced from the original 9 parts to 2 parts. The other ingredients and experimental steps are the same as those in Example 2.

[0077] Comparative Example 5

[0078] The difference between this comparative example and Example 2 is that in the steps of the preparation method of the PP resin foamed optical diffuser plate, mixture a and mixture b are put into a single screw extruder in a mass ratio of 2:1 and heated and melted, and the other components and experimental steps are the same as those in Example 2.

[0079] The diffuser plates prepared in Examples 1 to 3 and Comparative Examples 1 to 5 were tested.

[0080] Test method:

[0081] Light transmittance and haze are tested according to ASTM D1003 standard;

[0082] The center brightness and average brightness are tested according to GY / T 326-2019 standard;

[0083] Impact strength is tested according to ASTM D256 standard;

[0084] Heat deformation temperature is tested according to ASTM D648 standard;

[0085] Flame retardancy is tested according to UL94 standard;

[0086] Density is tested according to ASTM D792;

[0087] The test results are shown in Table 1.

[0088] Table 1 Diffuser plate performance test results

[0089]

[0090] From the experimental data in Table 1, the PP resin foamed optical diffuser plates prepared in each embodiment of the present application have a heat deformation temperature of more than 110°C, indicating that the diffuser plates prepared in each embodiment are not prone to softening and deformation at a high temperature and have good stability; the impact strength is greater than 85Kg / cm 2 , indicating that the diffuser plates prepared in each embodiment have high impact resistance, good mechanical properties, safety and durability; the flame retardancy reaches V0 level; the light transmittance is above 65%, the haze is greater than 80%, the center brightness is greater than 1800, the average brightness is more than 1100, and the center brightness is not much different from the average brightness, indicating that the diffuser plates prepared in the embodiments have good optical properties, high light transmittance and can be effectively scattered, have bright lighting effects, can well achieve uniform light distribution, so that the entire diffuser plate can effectively reduce glare while maintaining high brightness; the density is 1.0g / cm 3 Nearby, light texture, easy to carry, the upper / middle / lower layer thickness ratio is within the range of 1:(7~9):1, and the overall structure is stable.

[0091] Continuing to compare and analyze the data of Example 2 with the comparative example, it is found that after the PP resin in the upper and lower layer formulas of Comparative Example 1 is increased from 77 parts to 92 parts, and the PP-g-MAH resin is not added, the impact strength value of the diffuser plate decreases, the mechanical properties deteriorate, and the transmittance and haze of the diffuser plate are affected, causing the optical properties of the diffuser plate to deteriorate, indicating that the PP-g-MAH resin has a great influence on the mechanical properties of the diffuser plate and will affect the optical properties; after the PP resin in the upper and lower layer formulas of Comparative Example 2 is increased from 77 parts to 79 parts, and the copolymer microspheres are not added, the transmittance, haze, center brightness, and average brightness of the diffuser plate are significantly reduced, and the optical properties become extremely poor, indicating that the copolymer microspheres have a great influence on the optical properties of the diffuser plate; after 2 parts of silica are replaced by 2 parts of copolymer microspheres in the upper and lower layer formulas of Comparative Example 3, it can be found that the density of the diffuser plate The degree becomes larger, the diffuser plate becomes heavier, and the optical performance is much worse than that when copolymer microspheres are used; in the middle layer formula of comparative example 4, the GPPS resin is increased from 88 parts to 95 parts, and the foaming agent is reduced from the original 9 parts to 2 parts, the transmittance, haze, center brightness, and average brightness values ​​of the diffuser plate are all reduced, but compared with comparative example 2, the decrease is not so obvious, and the upper / middle / lower layer thickness ratio is also reduced, and the impact strength value is reduced, indicating that the proportion of the foaming agent in the system will have a certain influence on the optical and mechanical properties of the diffuser plate; in the preparation method of the PP resin foamed optical diffuser plate in comparative example 5, the mixture a and the mixture b are put into a single screw extruder at a mass ratio of 2:1 and heated and melted, which significantly changes the upper / middle / lower layer thickness ratio of the diffuser plate, and the impact strength value is significantly reduced, indicating that the mechanical strength and overall structural stability of the diffuser plate are greatly affected.

[0092] In summary, the present application provides a formula and process for successfully applying PP resin to a light diffuser plate, which has overall structural stability, excellent optical properties, and low manufacturing cost.

[0093] The above is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A PP resin foamed optical diffuser plate, characterized in that: The invention comprises an upper layer, a middle layer and a lower layer, wherein the upper layer and the lower layer are located on both sides of the middle layer, the thickness ratio of the upper layer, the middle layer and the lower layer is 1:(7-9):1, the upper layer and the lower layer have the same components, and the upper layer comprises the following components in parts by weight: 69-85 parts of PP resin, 10-20 parts of PP-g-MAH resin, 1-3 parts of copolymer microspheres, 3-5 parts of flame retardant, 0.3-0.7 parts of antioxidant, 0.08-0.1 6 parts of mineral oil, 0.4-1.2 parts of light stabilizer, 0.2-0.9 parts of ultraviolet absorber, 0.02-0.04 parts of brightener; the middle layer includes the following components in parts by mass: 83-93 parts of GPPS resin, 5-13 parts of foaming agent, 0.4-1.2 parts of antioxidant, 0.23-0.27 parts of mineral oil, 0.6-1 parts of light stabilizer, 0.4-1.1 parts of ultraviolet absorber, 0.37-0.43 parts of brightener.

2. The PP resin foamed optical diffuser plate according to claim 1, characterized in that: The antioxidant is at least one of antioxidant 1024 , antioxidant 1010 or antioxidant 1076 .

3. The PP resin foamed optical diffuser plate according to claim 1, characterized in that: The mineral oil is silicone oil or liquid paraffin.

4. The PP resin foamed optical diffuser plate according to claim 1, characterized in that: The light stabilizer is any one or more selected from the group consisting of light stabilizer 622, light stabilizer 770, and light stabilizer 944.

5. The PP resin foamed optical diffuser plate according to claim 1, characterized in that: The ultraviolet absorber is selected from one or more of the ultraviolet absorbers UV-327, UV-329, and UV-531.

6. The PP resin foamed optical diffuser plate according to claim 1, characterized in that: The whitening agent is fluorescent whitening agent CBS-127.

7. A method for preparing a PP resin foamed optical diffuser plate as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: preparing the copolymer microspheres; 1 to 3 parts of the copolymer microspheres, 69 to 85 parts of PP resin, 10 to 20 parts of PP-g-MAH resin, 3 to 5 parts of flame retardant, 0.3 to 0.7 parts of antioxidant, 0.08 to 0.16 parts of mineral oil, 0.4 to 1.2 parts of light stabilizer, 0.2 to 0.9 parts of ultraviolet absorber, and 0.02 to 0.04 parts of brightener are uniformly mixed to obtain a mixture a; 83-93 parts of the GPPS resin, 5-13 parts of a foaming agent, 0.4-1.2 parts of an antioxidant, 0.23-0.27 parts of a mineral oil, 0.6-1 parts of a light stabilizer, 0.4-1.1 parts of an ultraviolet absorber, and 0.37-0.43 parts of a brightener are uniformly mixed to obtain a mixture b; The mixture a and the mixture b are put into a single screw extruder in a mass ratio of 2:(3-5), heated and melted, three-layer co-extruded and embossed to obtain a finished product; Among them, the temperatures of each zone of the single-screw extruder are: zone one temperature is 180-190°C, zone two temperature is 190-200°C, zone three temperature is 210-220°C, zone four temperature is 210-220°C, zone five temperature is 225-235°C, zone six temperature is 215-225°C, zone seven temperature is 210-220°C, and the die head temperature is 205-215°C; the production speed is 310kg / h.

8. The method for preparing a PP resin foamed optical diffuser plate according to claim 7, characterized in that: The preparation of the copolymer microspheres comprises the following steps: 30-50 parts of maleic anhydride, 45-55 parts of styrene and 5-15 parts of azobisisobutyronitrile are respectively dissolved in 150-250 parts of isoamyl acetate, and nitrogen is passed through for 30-40 minutes, and then heated in a water bath at 70°C for 4-6 hours; the suspension after the reaction is centrifuged, the supernatant is removed, the solid is dispersed in n-hexane for washing, the filter residue is collected by filtration, and the filter residue is dried to obtain copolymer microspheres.

9. The method for preparing a PP resin foamed optical diffuser plate according to claim 8, characterized in that: The centrifugal speed is 2000-4000 r / min, and the centrifugal time is 20-30 min.

10. The method for preparing a PP resin foamed optical diffuser plate according to claim 8, characterized in that: The drying temperature is 90-110° C., and the drying time is 6-8 hours.

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