阅读说明：本技术 复合光扩散板及其制备方法 (Composite light diffusion plate and preparation method thereof ) 是由 不公告发明人 于 2020-12-31 设计创作，主要内容包括：本发明涉及一种复合光扩散板及其制备方法。复合光扩散板包括芯层,芯层的两侧分别设置有表层；制备芯层的原料包括按照质量份数的如下组分：聚苯乙烯80份～120份；以及扩散母粒10份～30份；其中,扩散母粒包括按照质量份数的如下组分：聚苯乙烯100份；以及光扩散剂2份～6份；制备表层的原料包括按照质量份数的如下组分：聚碳酸酯80份～120份；以及阻燃母粒0.5份～10份；其中,阻燃母粒包括按照质量份数的如下组分：以及本发明的上述复合光扩散板,降低了阻燃剂的添加量,同时能保证复合光扩散板的高扩散性,能够满足市场对光扩散板的机械性能、光学性能以及阻燃性的要求,有利于应用。(The invention relates to a composite light diffusion plate and a preparation method thereof. The composite light diffusion plate comprises a core layer, wherein surface layers are respectively arranged on two sides of the core layer; the core layer is prepared from the following raw materials in parts by mass: 80-120 parts of polystyrene; and 10-30 parts of diffusion master batch; the diffusion master batch comprises the following components in parts by mass: 100 parts of polystyrene; and 2-6 parts of light diffusant; the raw materials for preparing the surface layer comprise the following components in parts by mass: 80-120 parts of polycarbonate; and 0.5 to 10 parts of flame-retardant master batch; the flame-retardant master batch comprises the following components in parts by weight: the composite light diffusion plate disclosed by the invention reduces the addition amount of a flame retardant, can ensure high diffusivity of the composite light diffusion plate, can meet the requirements of the market on the mechanical property, the optical property and the flame retardance of the light diffusion plate, and is beneficial to application.)

1. The composite light diffusion plate is characterized by comprising a core layer, wherein surface layers are respectively arranged on two sides of the core layer;

the core layer is prepared from the following raw materials in parts by mass:

80-120 parts of polystyrene; and

10-30 parts of diffusion master batch;

the diffusion master batch comprises the following components in parts by weight:

100 parts of polystyrene; and

2-6 parts of light diffusant;

the raw materials for preparing the surface layer comprise the following components in parts by mass:

80-120 parts of polycarbonate; and

0.5-10 parts of flame-retardant master batch;

the flame-retardant master batch comprises the following components in parts by weight:

2. the composite diffuser plate as claimed in claim 1, wherein the raw materials for preparing the core layer comprise the following components in parts by mass:

100 parts of polystyrene; and

20 parts of diffusion master batch.

3. The composite light diffuser plate of claim 1, wherein the raw materials for preparing the surface layer comprise the following components in parts by mass:

100 parts of polycarbonate; and

5 parts of flame-retardant master batch.

4. The composite light diffuser plate of claim 1, wherein the light diffuser is selected from at least one of modified silicone, silica, and titanium dioxide.

5. The composite light diffuser plate of claim 1, wherein the flame retardant is a phosphorus-based flame retardant, and the flame retardant synergist is a phosphorus-based flame retardant synergist.

6. The composite light diffuser plate of claim 5, wherein the flame retardant is at least one selected from hydroquinone bis (diphenylphosphonate), triphenyl phosphate, and melamine pyrophosphate.

7. The composite light diffuser plate of claim 5, wherein the flame retardant synergist is at least one selected from hydroquinone bis [ di (1-methyl-2-phenyl) phosphonate ], zinc stearate and siloxane.

8. The composite light diffuser plate of claim 1, wherein the antioxidant is selected from at least one of 2, 6-di-tert-butyl-4-methylphenol, n-octadecyl 3, 5-di-tert-butyl-4-hydroxyphenylpropionate, and tris (1, 4-di-tert-butylphenyl) phosphite.

9. The composite light diffuser plate as claimed in claim 1, wherein the thickness ratio of the core layer to each of the surface layers is (60-90): (5-20).

10. The method for preparing the composite light diffusion plate as claimed in any one of claims 1 to 9, wherein the method comprises the following steps:

uniformly mixing the diffusion master batch according to a proportion, extruding and granulating, and cooling to obtain the diffusion master batch; uniformly mixing the flame-retardant master batch according to a proportion, extruding and granulating, and cooling to obtain the flame-retardant master batch;

uniformly mixing the raw materials for preparing the core layer in proportion, and extruding to form the core layer; uniformly mixing the raw materials for preparing the surface layer in proportion and then extruding to form the surface layer; and

and respectively attaching the two surface layers to two sides of the core layer, tightly pressing and attaching the core layer and the surface layers in a three-layer co-extrusion mode, and cooling to obtain the composite light diffusion plate.

Technical Field

The invention relates to the technical field of diffusion plates, in particular to a composite light diffusion plate and a preparation method thereof.

Background

At present, along with the gradual development of society, more and more lightening devices such as billboards, display screens and lamps can generate uneven light due to the gathering of point light sources or line light sources. A diffusion plate is generally used to solve the above problems because it has characteristics of high light diffusivity, high light transmittance, and good light-shielding property. The principle is that light is refracted, reflected and scattered when encountering two media with different refractive indexes (densities) in the traveling process.

Polystyrene PS is colorless, tasteless and transparent thermoplastic plastic, has excellent electrical insulation and optical performance, has light transmittance of 89%, and is low in cost, wide in source and strong in processability, so that the polystyrene PS is widely applied to the fields of display, illumination and the like. However, polystyrene is easy to burn, and a large amount of black smoke and dropping substances are accompanied during burning, so that fire disasters are easily caused to threaten personal safety. Therefore, it is necessary to add a flame retardant to polystyrene to achieve the flame retardant rating required by the application so as to expand the application range of polystyrene.

At present, the traditional process for producing a polystyrene light diffusion plate is to blend a polystyrene raw material with a light diffusion agent and other various functional additives, perform melt granulation, perform melt extrusion molding again according to a formula, blend a flame retardant and other additives in the first step of the production process, perform melt extrusion to obtain color master batches, and perform processing molding, so that a diffusion plate product is endowed with certain flame retardancy. However, if the addition amounts of the flame retardant and the flame retardant synergist in the polystyrene diffusion plate are too small, the flame retardancy of the polystyrene diffusion plate is difficult to meet the requirement; if the addition amount of the flame retardant and the flame retardant synergist is too much, the light transmittance and the light uniformity of the polystyrene diffusion plate are also greatly reduced, which is not beneficial to application.

Disclosure of Invention

Therefore, it is necessary to provide a composite light diffusion plate and a preparation method thereof, aiming at the problem of how to combine the light diffusion and the flame retardant performance.

The composite light diffusion plate comprises a core layer, wherein surface layers are respectively arranged on two sides of the core layer;

the core layer is prepared from the following raw materials in parts by mass:

80-120 parts of polystyrene; and

10-30 parts of diffusion master batch;

the diffusion master batch comprises the following components in parts by weight:

100 parts of polystyrene; and

2-6 parts of light diffusant;

the raw materials for preparing the surface layer comprise the following components in parts by mass:

80-120 parts of polycarbonate; and

0.5-10 parts of flame-retardant master batch;

the flame-retardant master batch comprises the following components in parts by weight:

according to the technical scheme, the core layer plays a role in light diffusion according to the proportion of the components, the surface layers playing a flame retardant role are arranged on two sides of the core layer, the addition amount of the flame retardant is reduced, meanwhile, the high diffusivity of the composite light diffusion plate can be ensured, the requirements of the market on the mechanical property, the optical property and the flame retardance of the light diffusion plate can be met, and the application is facilitated.

In one embodiment, the raw materials for preparing the core layer comprise the following components in parts by mass:

100 parts of polystyrene; and

20 parts of diffusion master batch.

In one embodiment, the raw materials for preparing the surface layer comprise the following components in parts by mass:

100 parts of polycarbonate; and

5 parts of flame-retardant master batch.

In one embodiment, the light diffusing agent is selected from at least one of modified silicone, silica and titanium dioxide.

In one embodiment, the flame retardant is a phosphorus flame retardant, and the flame retardant synergist is a phosphorus flame retardant synergist.

In one embodiment, the flame retardant is selected from at least one of hydroquinone bis (diphenylphosphonate), triphenyl phosphate, and melamine pyrophosphate.

In one embodiment, the flame retardant synergist is selected from at least one of hydroquinone bis [ di (1-methyl-2-phenyl) phosphonate ], zinc stearate, and silicone.

In one embodiment, the antioxidant is selected from at least one of 2, 6-di-tert-butyl-4-methylphenol, n-octadecyl 3, 5-di-tert-butyl-4-hydroxyphenylpropionate and tris (1, 4-di-tert-butylphenyl) phosphite.

In one embodiment, the thickness ratio of the core layer to each surface layer is (60-90): (5-20).

The preparation method of the composite light diffusion plate comprises the following steps:

uniformly mixing the diffusion master batch according to a proportion, extruding and granulating, and cooling to obtain the diffusion master batch; uniformly mixing the flame-retardant master batch according to a proportion, extruding and granulating, and cooling to obtain the flame-retardant master batch;

uniformly mixing the raw materials for preparing the core layer in proportion, and extruding to form the core layer; uniformly mixing the raw materials for preparing the surface layer in proportion and then extruding to form the surface layer; and

and respectively attaching the two surface layers to two sides of the core layer, tightly pressing and attaching the core layer and the surface layers in a three-layer co-extrusion mode, and cooling to obtain the composite light diffusion plate.

The preparation method of the composite light diffusion plate provided by the technical scheme of the invention is simple in process, and the prepared composite light diffusion plate can meet the requirements of the market on the mechanical property, the optical property and the flame retardance of the light diffusion plate, and is beneficial to application.

Drawings

FIG. 1 is a schematic diagram of a composite light diffuser plate according to an embodiment of the present invention;

fig. 2 is a flowchart of a method for manufacturing a composite light diffuser plate according to an embodiment of the present invention.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1, a composite light diffuser plate 100 according to an embodiment of the present invention includes a core layer 110, and surface layers 120 are respectively disposed on two sides of the core layer 110.

The core layer 110 is prepared from the following raw materials in parts by mass:

80-120 parts of polystyrene; and

10-30 parts of diffusion master batch;

the diffusion master batch comprises the following components in parts by mass:

100 parts of polystyrene; and

2-6 parts of light diffusant;

the raw materials for preparing the surface layer 120 comprise the following components in parts by mass:

80-120 parts of polycarbonate; and

0.5-10 parts of flame-retardant master batch;

the flame-retardant master batch comprises the following components in parts by weight:

in the above embodiment, the light diffusing agent 112 is uniformly dispersed in the core layer 110, which can increase the scattering and transmission of light, shield the light source and the glaring light source, and make the whole resin emit softer, more beautiful and more elegant light, so as to achieve the comfortable effect of light transmission and opaqueness. In the composite light diffusion plate, the core layer comprises the polystyrene and the diffusion master batch in the proportion, so that the light diffusion effect is achieved, and the high diffusivity of the composite light diffusion plate is ensured.

In the above embodiments, the flame retardant is a functional aid for imparting flame retardancy to the combustible polymer. The flame-retardant synergist is used for being compounded with a flame retardant for flame retardance. The antioxidant can prevent the adverse effect of oxygen on the composite light diffusion plate and prolong the service life. In the composite light diffusion plate, the surface layer comprises the polycarbonate and the flame-retardant master batch in the proportion, and is positioned on the outer side of the core layer, so that the addition amount of the flame retardant is reduced.

On the basis of the foregoing embodiment, the raw materials for preparing the core layer 110 include the following components in parts by mass:

100 parts of polystyrene; and

20 parts of diffusion master batch.

On the basis of the foregoing embodiment, the raw material for preparing the surface layer 120 includes the following components in parts by mass:

100 parts of polycarbonate; and

5 parts of flame-retardant master batch.

On the basis of the foregoing embodiment, the light diffusing agent 112 is selected from at least one of modified silicone, silica, and titanium dioxide. These types of light diffusing agents 112 are uniformly dispersed in the core layer 110, and function to diffuse light well.

On the basis of the foregoing embodiment, the flame retardant is a phosphorus flame retardant, and the flame-retardant synergist is a phosphorus flame-retardant synergist. The phosphorus flame retardant and the phosphorus flame retardant synergist have the advantages of no toxicity, low smoke, no halogen and the like, and in the combustion process, the phosphorus flame retardant and the phosphorus flame retardant synergist generate metaphosphoric acid and phosphoric acid after being heated, and the metaphosphoric acid and the phosphoric acid can form a carbonization layer on the surface of a polymer material to block the release of combustible gas and isolate external heat and oxygen from entering the inside of a base material, so that the flame retardant purpose is achieved.

On the basis of the foregoing embodiment, the flame retardant is selected from at least one of hydroquinone bis (diphenylphosphonate), triphenyl phosphate, and melamine pyrophosphate.

Based on the foregoing embodiment, the flame retardant synergist is selected from at least one of hydroquinone bis [ di (1-methyl-2-phenyl) phosphonate ], zinc stearate and siloxane. The flame retardant synergist is matched with the flame retardant, so that the flame retardant effect is better.

In addition to the foregoing embodiments, the antioxidant is selected from at least one of 2, 6-di-tert-butyl-4-methylphenol, n-octadecyl 3, 5-di-tert-butyl-4-hydroxyphenylpropionate and tris (1, 4-di-tert-butylphenyl) phosphite.

On the basis of the foregoing embodiment, the thickness ratio of the core layer 110 to each of the skin layers 120 is (60 to 90): (5-20). At this time, the surface layer 120 may have a good flame retardant property within a thin thickness range, while not affecting the high diffusivity of the core layer 110. The specific thicknesses of the core layer 110 and the surface layer 120 can be set according to actual requirements.

According to the technical scheme, the core layer plays a role in light diffusion according to the proportion of the components, the surface layers playing a flame retardant role are arranged on two sides of the core layer, the addition amount of the flame retardant is reduced, meanwhile, the high diffusivity of the composite light diffusion plate can be ensured, the requirements of the market on the mechanical property, the optical property and the flame retardance of the light diffusion plate can be met, and the application is facilitated.

Referring to fig. 2, a method for preparing a composite light diffuser plate according to an embodiment of the present invention includes the following steps:

s10, uniformly mixing the diffusion master batch according to the proportion, extruding and granulating, and cooling to obtain the diffusion master batch; and uniformly mixing the flame-retardant master batch according to a proportion, extruding and granulating, and cooling to obtain the flame-retardant master batch.

Specifically, the steps of uniformly mixing the diffusion master batch according to the proportion, then extruding and granulating, and cooling to obtain the diffusion master batch are as follows: mixing 100 parts of polystyrene and 2-6 parts of light diffusant from different bins respectively, feeding the mixture into a double-screw extrusion granulator, heating and melting the mixture in a melting zone, extruding the mixture by double screws, cooling and molding the mixture by circulating water, granulating the mixture, removing defective products by a vibrating screen, and collecting transparent diffusion master batches after cone mixing.

In the step of preparing the diffusion master batch, the double-screw extruder is a ten-temperature-zone double-screw extruder, and the temperature of each zone and the temperature of a die head are respectively as follows: the temperature of the first area is 50-80 ℃; the temperature of the second area is 160-200 ℃; the temperature of the three zones is 180-220 ℃; the temperature of the fourth area is 180-220 ℃; the temperature of the fifth area is 200-240 ℃; the temperature of the sixth area is 200-240 ℃; the temperature of the seventh area is 200-240 ℃; the temperature of the eight regions is 200-240 ℃; the temperature of the ninth area is 200-240 ℃; the temperature of the ten areas is 200-240 ℃; the temperature of the die head is 200-240 ℃; the reasonable temperature is set to ensure that the diffusion master batches are mixed more uniformly.

In the step of preparing the diffusion master batch, the production speed of the double-screw extruder is 200Kg/h to 300 Kg/h. Can guarantee through setting up reasonable production speed that the diffusion master batch mixes more evenly, and prevent that the diffusion master batch from crossing to smelt to make required diffusion master batch.

Specifically, the steps of uniformly mixing the flame-retardant master batch according to the proportion, then extruding and granulating, and cooling to obtain the flame-retardant master batch are as follows: mixing 100 parts of polycarbonate, 5-12 parts of flame retardant, 0-4 parts of flame retardant synergist and 0.5-2 parts of antioxidant from different bins respectively, feeding into a double-screw extrusion granulator, heating and melting in a melting zone, extruding by double screws, cooling and molding by circulating water, granulating, removing defective products by a vibrating screen, mixing by a cone, and collecting transparent flame retardant master batches.

In the step of preparing the diffusion master batch, the double-screw extruder is a ten-temperature-zone double-screw extruder, and the temperature of each zone and the temperature of a die head are respectively as follows: the temperature of the first area is 60-100 ℃; the temperature of the second area is 200-240 ℃; the temperature of the three zones is 220-260 ℃; the temperature of the fourth area is 220-260 ℃; the temperature of the fifth area is 240-280 ℃; the temperature of the sixth area is 240-280 ℃; the temperature of the seventh area is 240-280 ℃; the temperature of the eight regions is 240-280 ℃; the temperature of the nine areas is 240-280 ℃; the temperature of the ten areas is 240-280 ℃; the temperature of the die head is 240-280 ℃; the flame-retardant master batches are uniformly mixed by setting reasonable temperature.

In the step of preparing the flame-retardant master batch, the production speed of the double-screw extruder is 200Kg/h to 300 Kg/h. Can guarantee through setting up reasonable production speed that the diffusion master batch mixes more evenly, and prevent that the diffusion master batch from crossing to smelt to make required fire-retardant master batch.

The components of the diffusion master batch and the flame-retardant master batch can be uniformly mixed by extruding and granulating through a double-screw extruder, and the prepared diffusion master batch and the prepared flame-retardant master batch are easier to take and store.

It should be noted that, in step S10, the order of preparing the diffusion mother particles and the flame retardant mother particles is not limited.

S20, uniformly mixing the raw materials for preparing the core layer in proportion, and extruding to form the core layer; the raw materials for preparing the surface layer are uniformly mixed according to a proportion and then extruded to form the surface layer.

Specifically, the step of extruding the raw materials for preparing the core layer after uniformly mixing the raw materials in proportion to form the core layer comprises the following steps: 80-100 parts of polystyrene and 10-30 parts of diffusion master batch are respectively sucked through a feed bin, are uniformly mixed, are heated in a melting zone, are extruded from upper and lower layer outlets of a die head of an extruder by a single screw, and the thickness of an extruded plate can be controlled by adjusting a baffle plate at the die head.

In the step of preparing the core layer, the temperature of each zone of the single screw extruder and the temperature of the die head are respectively as follows: the temperature of the first area is 190-200 ℃; the temperature of the second area is 200-210 ℃; the temperature of the three zones is 200-210 ℃; the temperature of the fourth area is 210-220 ℃; the temperature of the fifth area is 180-200 ℃; the temperature of the sixth area is 200-210 ℃; the temperature of the seventh area is 210-220 ℃; the temperature of the eight regions is 220-230 ℃; the temperature of the nine areas is 220-230 ℃; the temperature of the ten areas is 220-230 ℃; the temperature of the eleventh area is 220-230 ℃; the temperature of the twelve areas is 220-230 ℃; the temperature of the thirteen areas is 220-230 ℃; the temperature of the fourteen areas is 220-230 ℃; the temperature of the fifteen areas is 210-220 ℃; the temperature of the die head is 210-220 ℃; the raw materials for preparing the core layer are ensured to be mixed more uniformly by setting reasonable temperature.

In the step of preparing the core layer, the production speed of the single-screw extruder is 100 Kg/h-400 Kg/h. Through setting up reasonable production speed can guarantee that the raw materials of preparation sandwich layer mix more evenly, and prevent that the raw materials of preparation sandwich layer from crossing to smelt to make required sandwich layer.

Specifically, the step of extruding the raw materials for preparing the surface layer after uniformly mixing the raw materials in proportion to form the surface layer comprises the following steps: 80-120 parts of polycarbonate and 0.5-10 parts of flame-retardant master batch are respectively sucked through a feed bin, are uniformly mixed, are heated in a melting zone, and are extruded from upper and lower layer outlets of a die head of an extruder by a single screw, and the thickness of an extruded plate can be controlled by adjusting a baffle plate at the die head.

In the step of preparing the skin layer, the temperatures of the zones of the single-screw extruder and the die head are respectively as follows: the temperature of the first area is 220-230 ℃; the temperature of the second area is 230-240 ℃; the temperature of the three zones is 230-240 ℃; the temperature of the fourth area is 240-250 ℃; the temperature of the fifth area is 210-230 ℃; the temperature of the sixth area is 230-240 ℃; the temperature of the seventh area is 240-250 ℃; the temperature of the eight regions is 250-260 ℃; the temperature of the nine areas is 250-260 ℃; the temperature of the ten areas is 250-260 ℃; the temperature of the eleventh area is 250-260 ℃; the temperature of the twelve areas is 250-260 ℃; the temperature of thirteen areas is 250-260 ℃; the temperature of the fourteen areas is 250-260 ℃; the temperature of the fifteen areas is 240-250 ℃; the temperature of the die head is 240-250 ℃; the reasonable temperature is set to ensure that the raw materials for preparing the surface layer are mixed more uniformly.

In the step of preparing the surface layer, the production speed of the single-screw extruder is 100 Kg/h-400 Kg/h. Can guarantee through setting up reasonable production speed that the raw materials on preparation top layer mixes more evenly, and prevents that the raw materials on preparation top layer from crossing to smelt to make required top layer.

And S30, respectively attaching the two surface layers to two sides of the core layer, tightly pressing and attaching the core layer and the surface layers in a three-layer co-extrusion mode, and cooling to obtain the composite light diffusion plate.

And after cooling, the steps of cutting and dust-free cleaning can be further included, and finally the prepared composite light diffusion plate is put in storage.

The preparation method of the composite light diffusion plate provided by the technical scheme of the invention is simple in process, and the prepared composite light diffusion plate can meet the requirements of the market on the mechanical property, the optical property and the flame retardance of the light diffusion plate, and is beneficial to application.

With reference to the above embodiments, the technical solutions of the present application are illustrated for the sake of making the technical solutions of the present application more specific and clear and easy to understand, but it should be noted that the contents to be protected by the present application are not limited to the following embodiments 1 to 14.

Examples 1 to 14

The preparation method of the composite light diffusion plate in the embodiment 1 to 14 is as follows:

weighing the raw materials according to the mass parts in the table 1; mixing polystyrene and a light diffusant from different bins respectively, feeding the mixture into a double-screw extrusion granulator, heating and melting in a melting zone, extruding by double screws, cooling and molding by circulating water, granulating, removing defective products by a vibrating screen, and collecting transparent diffusion master batches after cone mixing. Wherein the temperature of each zone and the temperature of a die head of the double-screw extruder are respectively as follows: the temperature of the first area is 50-80 ℃; the temperature of the second area is 160-200 ℃; the temperature of the three zones is 180-220 ℃; the temperature of the fourth area is 180-220 ℃; the temperature of the fifth area is 200-240 ℃; the temperature of the sixth area is 200-240 ℃; the temperature of the seventh area is 200-240 ℃; the temperature of the eight regions is 200-240 ℃; the temperature of the ninth area is 200-240 ℃; the temperature of the ten areas is 200-240 ℃; the temperature of the die head is 200-240 ℃; the production rate of the twin-screw extruder was 220 Kg/h.

Weighing the raw materials according to the mass parts in the table 2; respectively mixing polycarbonate, a flame retardant, a flame-retardant synergist and an antioxidant from different bins, feeding the mixture into a double-screw extrusion granulator, heating and melting the mixture in a melting zone, extruding the mixture by double screws, cooling and molding the mixture by circulating water, granulating the mixture, removing defective products by a vibrating screen, and collecting transparent flame-retardant master batches after cone mixing. Wherein the temperature of each zone and the temperature of a die head of the double-screw extruder are respectively as follows: the temperature of the first area is 60-100 ℃; the temperature of the second area is 200-240 ℃; the temperature of the three zones is 220-260 ℃; the temperature of the fourth area is 220-260 ℃; the temperature of the fifth area is 240-280 ℃; the temperature of the sixth area is 240-280 ℃; the temperature of the seventh area is 240-280 ℃; the temperature of the eight regions is 240-280 ℃; the temperature of the nine areas is 240-280 ℃; the temperature of the ten areas is 240-280 ℃; the die head temperature is 240-280 ℃. The production rate of the twin-screw extruder was 220 Kg/h.

Weighing the raw materials according to the mass parts in the table 3; respectively sucking the polystyrene and the diffusion master batches through a discharging bin, uniformly mixing, heating in a melting zone, and extruding a core layer from upper and lower layer outlets of a die head of an extruder by a single screw; wherein the temperature of each zone and the temperature of the die head of the single-screw extruder are respectively as follows: the temperature of the first area is 190-200 ℃; the temperature of the second area is 200-210 ℃; the temperature of the three zones is 200-210 ℃; the temperature of the fourth area is 210-220 ℃; the temperature of the fifth area is 180-200 ℃; the temperature of the sixth area is 200-210 ℃; the temperature of the seventh area is 210-220 ℃; the temperature of the eight regions is 220-230 ℃; the temperature of the nine areas is 220-230 ℃; the temperature of the ten areas is 220-230 ℃; the temperature of the eleventh area is 220-230 ℃; the temperature of the twelve areas is 220-230 ℃; the temperature of the thirteen areas is 220-230 ℃; the temperature of the fourteen areas is 220-230 ℃; the temperature of the fifteen areas is 210-220 ℃; the die head temperature is 210-220 ℃. The production rate of the single-screw extruder is 340 Kg/h.

Weighing the raw materials according to the mass parts in the table 3; respectively sucking the polycarbonate and the flame-retardant master batch through a discharging bin, uniformly mixing, and extruding a surface layer from an upper layer outlet and a lower layer outlet of a die head of an extruder by a single screw after the temperature of a melting zone is raised; wherein the temperature of each zone and the temperature of the die head of the single-screw extruder are respectively as follows: the temperature of the first area is 220-230 ℃; the temperature of the second area is 230-240 ℃; the temperature of the three zones is 230-240 ℃; the temperature of the fourth area is 240-250 ℃; the temperature of the fifth area is 210-230 ℃; the temperature of the sixth area is 230-240 ℃; the temperature of the seventh area is 240-250 ℃; the temperature of the eight regions is 250-260 ℃; the temperature of the nine areas is 250-260 ℃; the temperature of the ten areas is 250-260 ℃; the temperature of the eleventh area is 250-260 ℃; the temperature of the twelve areas is 250-260 ℃; the temperature of thirteen areas is 250-260 ℃; the temperature of the fourteen areas is 250-260 ℃; the temperature of the fifteen areas is 240-250 ℃; the die head temperature is 240-250 ℃. The production rate of the single-screw extruder is 100 Kg/h.

And respectively attaching the two surface layers to two sides of the core layer, tightly pressing and attaching the core layer and the surface layers in a three-layer co-extrusion mode, then utilizing traction cooling, and cutting and then cleaning without dust to obtain the composite light diffusion plate of the embodiment 1-14. The core layer thickness of the composite light diffusion plate of embodiments 1 to 14 is 1.7mm, and the thickness of both the surface layers is 0.15 mm.

TABLE 1 raw material composition and compounding ratio for preparing diffusion masterbatch

Table 2 raw material components and mixture ratio for preparing flame-retardant master batch

TABLE 3 raw material composition and compounding ratio for preparing core layer and surface layer

And (3) performance testing:

the composite light diffusion plates of examples 1 to 14 were tested according to the following methods or standards, and the test results are shown in table 4.

1. Visible light transmittance: testing according to ISO 13468-1 standard;

2. haze: testing according to ISO 14782 standard;

3. flame retardant rating: the test was carried out according to the UL94 standard.

Table 4 Performance test results of the composite light diffusion plates of examples 1 to 14

Examples

1

2

3

4

5

6

7

Transmittance of light

60.3％

60.6％

61.2％

61.4％

61.5％

61.8％

62.1％

Haze degree

99.4％

99.4％

99.3％

99.5％

99.6％

99.4％

99.6％

Flame retardant rating

V2

V2

V1

V2

V2

V2

V2

Examples

8

9

10

11

12

13

14

Transmittance of light

62.0％

61.8％

61.6％

61.4％

61.1％

60.6％

60.2％

Haze degree

99.5％

99.5％

99.7％

99.6％

99.4％

99.5％

99.5％

Flame retardant rating

V2

V2

V2

V2

V1

V2

V1

As can be seen from table 4, in the composite light diffusion plates of examples 1 to 14, the selection of the flame retardant, the flame retardant synergist, the antioxidant and other auxiliaries has no influence on the optical properties such as the light transmittance and the haze of the composite light diffusion plate; the flame retardant and the flame-retardant synergist are matched to generate an obvious effect on the flame retardant performance of the composite light diffusion plate, and the flame retardant grade of the surface layer of the composite light diffusion plate is improved by 1-2 grades from the traditional V0 grade; as can be seen from the flame retardant rating of the composite light diffuser plates of examples 3, 12 and 14, the effect of melamine pyrophosphate and siloxane combination is relatively weak.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.