A single-layer foamed diffusion plate and a method for manufacturing the same

Abstract

The present application relates to the technical field of light diffusion plate, and more particularly to a single-layer skin foaming diffusion plate and a preparation method thereof. The single-layer skin foaming diffusion plate is formed by extrusion molding of the following raw materials: 88-96% of plastic base material, 1-20% of toughening agent, 0.1-1% of antioxidant, 0.1-1% of organic silicon diffusing agent, 0.01-1% of foaming agent, and 0.01-0.15% of nucleating agent. The mass ratio of the toughening agent to the foaming agent is 1:(0.01-0.1). By introducing the toughening agent into the raw materials of the single-layer skin foaming diffusion plate, the brittleness of the diffusion plate can be reduced, and the impact resistance of the diffusion plate can be improved. By modification of the toughening agent and the foaming agent, and by strictly controlling the usage ratio of the toughening agent and the foaming agent within the range of 1:(0.005-0.01), and by using the remaining raw materials such as the antioxidant and the nucleating agent together, the single-layer skin foaming diffusion plate with a small thickness can be prepared, the mechanical properties are good, the manufacturing cost is low, and the single-layer skin foaming diffusion plate also has excellent foaming effect and optical properties.

Description

Technical Field

[0001] This invention relates to the field of light diffusion plate technology, and in particular to a single-layer skin foamed diffusion plate and its preparation method. Background Technology

[0002] Light diffusion materials are key components in LED lighting and display fields. Because LEDs are point light sources, their concentrated light emission can cause glare. Therefore, light diffusion materials are needed to diffuse the point light source into a surface light source. Traditional light diffusion materials use organic or inorganic high-refractive-index materials, such as titanium dioxide, calcium carbonate, organosilicon microspheres, and PMMA microspheres. These materials are added to the substrate of the substrate to achieve light diffusion.

[0003] However, these light-diffusing materials inevitably experience light absorption and scattering losses, reducing light extraction efficiency. To avoid these problems, gas was introduced as a light-diffusing bubble plate. Since the refractive index of gas is 1, light undergoes total internal reflection when passing through the solid-gas interface, altering the light path and preventing photon absorption. Therefore, this type of bubble plate offers significantly improved luminous efficiency and uniformity compared to traditional light-diffusing plates. Currently, commonly used blowing agents for this type of bubble plate include carbonates, azodicarbonamides, and benzenesulfonyl hydrazines.

[0004] However, this type of bubble sheet also has the following drawbacks: the mechanical properties of the plastic substrate decrease after foaming. Currently, a sandwich structure is used, with the foamed layer sandwiched in the middle to prevent the plastic from becoming too brittle and breaking. For example, patent CN202210434579.7, "A Multi-Layer Co-Extruded Foamed Diffusion Board and Its Preparation Method and Application," describes a foamed diffusion board made by multi-layer co-extrusion of a main base layer (containing foaming agent) and protective layers on both sides of the main base layer. However, in existing sandwich structures, the thickness of the protective layer needs to be controlled at around 0.1 mm. In actual production, it is difficult to control the extrusion amount of the protective layer (skin) and the foamed layer, resulting in uneven thickness and still causing uneven optical properties. In addition, because the above-mentioned sandwich structure has a protective layer, a main base layer, and a protective layer stacked sequentially, it is difficult to make the material thinner. The thickness of the entire bubble sheet is usually more than 1.0 mm, increasing material costs. Summary of the Invention

[0005] The main objective of this invention is to provide a single-layer skin foamed diffusion plate and its preparation method, which aims to improve the problems of uneven thickness and uneven optical performance of existing multi-layer co-extruded foamed diffusion plates. At the same time, it also solves the technical problems of large finished product thickness and high production cost of existing multi-layer co-extruded foamed diffusion plates.

[0006] To achieve the above objectives, the present invention proposes a single-layer skin foamed diffusion plate, wherein the single-layer skin foamed diffusion plate is extruded and formed by mixing the following raw materials: 88-96% plastic substrate, 1-20% toughening agent, 0.1-1% antioxidant, 0.1-1% organosilicon diffusing agent, 0.01-1% foaming agent, and 0.01-0.15% nucleating agent, wherein the mass ratio of the toughening agent to the foaming agent is 1:0.01-0.1.

[0007] Preferably, the toughening agent comprises at least one of styrene-butadiene-styrene block copolymer, styrene-butadiene resin, methyl methacrylate-butadiene-styrene terpolymer, thermoplastic elastomer, or thermoplastic polyurethane.

[0008] Preferably, the foaming agent includes at least one of sodium bicarbonate, magnesium bicarbonate, calcium carbonate, azodicarbonamide, citric acid, and sodium citrate.

[0009] Preferably, the nucleating agent includes at least one of magnesium silicate, sodium citrate, sodium oxalate, alumina, nano-silica, nano-titanium dioxide, or silicone oil.

[0010] Preferably, the antioxidant comprises at least one selected from butylated hydroxyanisole, butylated hydroxytoluene, tert-butylhydroquinone, diisodecyl phosphite, pentaerythritol diphosphite, bis(2,2,6,6-tetramethylpiperidinyl) sebacate, tris(2,4-di-tert-butylphenyl) phosphite, and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0011] Preferably, the thickness of the single-layer skin foamed diffusion plate is 0.6-3.0 mm.

[0012] Preferably, the plastic substrate is GPPS polystyrene.

[0013] In addition, the present invention also proposes a method for preparing a single-layer skin foamed diffusion plate, comprising the following steps: mixing the raw materials of the single-layer skin foamed diffusion plate evenly according to the formula to form a mixture, extruding the mixture through an extrusion device to obtain a polymer melt, the polymer melt being formed by three-roll molding, and then cooled, shaped and post-treated to obtain the single-layer skin foamed diffusion plate.

[0014] Preferably, the extrusion temperature of the extrusion equipment is 190-240℃, and the die outlet temperature of the extrusion equipment is 220-250℃.

[0015] Preferably, after the polymer melt is extruded from the extrusion equipment, it is sequentially formed by three rollers: a front embossing roller, a middle embossing roller, and a rear embossing roller.

[0016] The roughness Ra of the embossing front roller is 10-20μm, and the roller temperature of the embossing front roller is 100-140℃.

[0017] The roughness Ra of the embossing roller is 7-12μm, and the roller temperature of the embossing roller is 90-130℃;

[0018] The surface roughness Ra of the embossing roller is 20-40μm, and the roller temperature is 70-105℃.

[0019] Compared with the prior art, the single-layer skin foamed diffusion plate and its preparation method of the present invention have the following advantages:

[0020] Beneficial effects:

[0021] 1. This solution introduces a toughening agent into the raw materials of a single-layer skin foamed diffuser plate, which can reduce the brittleness of the diffuser plate and improve its impact resistance. At the same time, by modifying the toughening agent and foaming agent in combination, and strictly controlling the ratio of toughening agent to foaming agent within the range of 1:(0.005-0.01), and by using other raw materials such as antioxidants and nucleating agents, a single-layer skin foamed diffuser plate with a small thickness can be produced. It has good mechanical properties, low production cost, and also has excellent foaming effect and optical properties.

[0022] 2. Regarding the preparation method, this scheme strictly controls the extrusion temperature of the extruder die head device to 220-250℃, thereby controlling the foaming effect during the extrusion of the single-layer skin foamed diffuser plate. This ensures that the generated bubbles are of suitable size and not easily broken, further improving the optical properties of the single-layer skin foamed diffuser plate. Furthermore, after the polymer melt exits the die, it passes sequentially through three embossing rollers: the front embossing roller, the middle embossing roller, and the rear embossing roller, resulting in a matte finish on the single-layer skin foamed diffuser plate, with better diffusion effect and superior optical properties. Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0025] A single-layer skin foamed diffusion plate, by mass percentage, is formed by extruding a mixture of the following raw materials: 88-96% plastic substrate, 1-20% toughening agent, 0.1-1% antioxidant, 0.1-1% silicone diffuser, 0.01-1% foaming agent, and 0.01-0.15% nucleating agent, wherein the mass ratio of the toughening agent to the foaming agent is 1:(0.01-0.1); the thickness of the obtained single-layer skin foamed diffusion plate is 0.6-3.0 mm.

[0026] The toughening agent includes at least one of styrene-butadiene-styrene block copolymer (SBS), styrene-butadiene resin, methyl methacrylate-butadiene-styrene terpolymer (MBS), thermoplastic elastomer (TPE), or thermoplastic polyurethane (TPU); the foaming agent includes at least one of sodium bicarbonate, magnesium bicarbonate, calcium carbonate, azodicarbonamide, citric acid, or sodium citrate; the nucleating agent includes at least one of magnesium silicate, sodium citrate, sodium oxalate, alumina, nano-silica, nano-titanium dioxide, or silicone oil; The antioxidants include at least one of butylated hydroxyanisole, butylated hydroxytoluene, tert-butylhydroquinone, diisodecyl phosphite, pentaerythritol diphosphite, bis(2,2,6,6-tetramethylpiperidinyl) sebacate (antioxidant 770), tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168), and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010); the plastic substrate is GPPS (polystyrene), which has good optical properties and processing properties.

[0027] The single-layer skin foamed diffuser plate in this solution is suitable for various display and lighting applications, and is especially suitable as a light diffusion backplate for lamps or displays.

[0028] Specifically, a toughening agent is introduced into the raw materials of the single-layer skin foamed diffuser plate, which can reduce the brittleness of the diffuser plate and improve its impact resistance. At the same time, through the combined modification of the toughening agent and the foaming agent, the ratio of the toughening agent to the foaming agent is strictly controlled within the range of 1:(0.01-0.1). With the combined use of other raw materials such as antioxidants and nucleating agents, the sandwich structure of the existing multi-layer co-extruded foamed diffuser plate can be eliminated, and a single-layer skin foamed diffuser plate can be made. The overall mechanical properties are better, the production cost is lower, and the thickness is thinner, with a minimum thickness of 0.5mm. At the same time, the single-layer skin foamed diffuser plate also has excellent foaming effect and optical properties.

[0029] In addition, the present invention also proposes a method for preparing a single-layer skin foamed diffusion plate, comprising the following steps: mixing the raw materials of the single-layer skin foamed diffusion plate evenly according to the formula to form a mixture, extruding the mixture through an extrusion device to obtain a polymer melt, the polymer melt being formed by three-roll molding, and then cooled and shaped to obtain the single-layer skin foamed diffusion plate.

[0030] The extrusion temperature of the extrusion equipment is 190-240℃, and the die outlet temperature is 220-250℃. After the polymer melt is extruded from the extrusion equipment, it passes through a front embossing roller, a middle embossing roller, and a rear embossing roller in sequence for three-roll forming. The roughness Ra of the front embossing roller is 10-20μm, and the roller temperature is 100-140℃. The roughness Ra of the middle embossing roller is 7-12μm, and the roller temperature is 90-130℃. The roughness Ra of the rear embossing roller is 20-40μm, and the roller temperature is 70-105℃.

[0031] In terms of preparation method, after the raw materials for the single-layer skin foamed diffusion plate are mixed, they are first extruded through an extrusion machine (extruder). The specific melting temperature is 190-240℃. The extruder includes zones one, two, three, four, five, six, eight, nine, a screen changer, a metering pump, and a die head device. Among them, the heating temperature of zone one is 190℃-205℃, the heating temperature of zone two is 195℃-210℃, the heating temperature of zone three is 200℃-220℃, the heating temperature of zone four is 210℃-230℃, the heating temperature of zone five is 220℃-240℃, and the heating temperature of zone six is ​​220℃-240℃. The heating temperatures are as follows: 40℃, Zone 7: 210℃-230℃, Zone 8: 210℃-230℃, Zone 9: 210℃-230℃, Screen changer: 210℃-230℃, Metering pump: 220℃-240℃, Die head assembly: 210℃-250℃. Furthermore, this scheme strictly controls the extrusion outlet temperature of the extruder die head assembly to 220-250℃, thereby controlling the foaming effect during extrusion of the single-layer skin foamed diffuser plate. This ensures that the generated bubbles are of suitable size and not easily broken, ultimately improving the optical performance of the single-layer skin foamed diffuser plate.

[0032] After the polymer melt exits the mold, it passes through three embossing rollers in sequence: the front embossing roller, the middle embossing roller, and the rear embossing roller. During the three-roll forming process, the roughness and roller temperature of the front embossing roller, the middle embossing roller, and the rear embossing roller must be controlled within a suitable range. Specifically, the roughness Ra of the front embossing roller is 10-20μm, and the roller temperature is 100-140℃; the roughness Ra of the middle embossing roller is 7-12μm, and the roller temperature is 90-130℃; and the roughness Ra of the rear embossing roller is 20-40μm, and the roller temperature is 70-105℃. The diffuser plate obtained after passing through these rollers has an Rz of about 20-50μm, resulting in a matte finish on the single-layer skin foamed diffuser plate with good diffusion effect and excellent optical properties. In addition, the discharge speed and spacing of the embossing roller can be controlled. Generally, the discharge speed is adjusted in the range of 1-30 r / min according to the different thicknesses of the light diffusion plate, while the spacing can be adjusted in the range of 0.5-3.0 mm.

[0033] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0034] Comparative Example 1

[0035] A method for preparing a single-layer foamed diffuser plate includes the following steps: 100 parts by weight of polystyrene, 0.02 parts by weight of foaming agent (sodium bicarbonate), 3 parts by weight of light diffusing agent, 7 parts by weight of titanium dioxide, 2 parts by weight of UV stabilizer (UV531), and 1 part by weight of antioxidant are mixed evenly to form a mixture. The mixture is extruded through an extruder (extrusion temperature of 190-240℃, extrusion die temperature of 220℃) to obtain a polymer melt. The polymer melt is shaped by embossing rollers (three rollers with roughness of 8μm, 16μm, and 20μm, and roller temperatures of 100℃, 100℃, and 100℃). After cooling, shaping, and post-treatment, a single-layer foamed diffuser plate with a thickness of 0.8mm is obtained.

[0036] Example 1

[0037] In this embodiment, all preparation steps and parameters are the same as in Comparative Example 1, except that the single-layer skin foamed diffusion plate raw material used in this scheme specifically includes: GPPS 95.37%, toughening agent (SBS styrene-butadiene resin) 3%, antioxidant-[3-(2,4-di-tert-butylphenyl)propionate] pentaerythritol ester 0.3%, tris(2,4-di-tert-butylphenyl) phosphite ester 0.3%, organosilicon diffusing agent 1%, foaming agent (sodium bicarbonate) 0.02%, and nucleating agent (sodium citrate) 0.01%.

[0038] Example 2

[0039] A method for preparing a single-layer skin foamed diffuser plate includes the following steps: 93.87% GPPS, 5% toughening agent SEBS (styrene-butadiene-styrene block copolymer), 0.5% antioxidant (butylated hydroxytoluene), 0.5% organosilicon diffuser, 0.03% foaming agent (sodium bicarbonate), 0.05% nucleating agent light calcium carbonate, and 0.05% nano titanium dioxide are mixed evenly to form a mixture. The mixture is extruded through an extruder (extrusion temperature 190-240℃, extrusion die temperature 245℃) to obtain a polymer melt. The polymer melt is shaped by an embossing roller (roughness Ra 10μm, roller temperature 70-120℃), and then cooled, shaped, and post-treated to obtain a single-layer skin foamed diffuser plate with a thickness of 0.8mm.

[0040] Example 3

[0041] A method for preparing a single-layer skin foamed diffuser plate includes the following steps: GPPS 93.82%, toughening agent (thermoplastic polyurethane) 5%, antioxidant (pentaerythritol diphosphite) 0.5%, organosilicon diffuser 0.5%, foaming agent (sodium bicarbonate) 0.03%, and nucleating agents (nano silica 0.1% and nano titanium dioxide 0.05%) are mixed to form a polymer melt. The mixture is extruded through an extruder (extrusion temperature 190-240℃, extruder die temperature 240℃) to obtain a polymer melt. The polymer melt is passed through an embossing roller (roughness Ra 12μm, roller temperature 70-120℃), and then cooled, shaped, and post-treated to obtain a single-layer skin foamed diffuser plate with a thickness of 0.8mm.

[0042] The single-layer foamed diffusion plates prepared in Examples 1-3 and Comparative Example 1 were subjected to the following performance tests, and the specific test results are shown in the table below:

[0043]

[0044] As can be seen from the test results of Comparative Example 1 and Example 1 in the table above, the finished product made by directly using existing foamed diffusion plate raw materials has poor impact resistance (bubble diameter greater than 240μm, bubble number greater than 180 / cm). 2 If the impact strength is less than 8 J / cm², a qualified diffuser plate cannot be obtained. In Example 1, after using the single-layer skin foamed diffuser plate raw material of this scheme, the impact resistance of the obtained single-layer skin foamed diffuser plate was improved due to adjustments in the composition and ratio of the raw material and strict limitations on the mass ratio of the foaming agent and toughening agent. This resulted in a single-layer skin foamed diffuser plate with a smaller thickness and better performance.

[0045] The performance test results of the single-layer skin foamed diffusion plate obtained from Examples 1-3 show that the foaming effect of the single-layer skin foamed diffusion plate of this scheme is good, with a bubble diameter ≥100μm and a bubble number ≥150 / cm. 2 Impact strength ≥11J / cm2, transmittance ≥45%, haze around 93%, optical performance meets standard requirements, and mechanical properties are even better.

[0046] Example 4

[0047] In this embodiment, all preparation steps and parameters are the same as in Example 2. The difference lies in the amount of toughening agent / foaming agent, i.e., the mass ratio, as shown in the table below:

[0048]

[0049]

[0050] The diffusion plate prepared in Example 4 was subjected to performance testing, and the specific test results are shown in the table below:

[0051]

[0052]

[0053] The test data in the table above show that a mass ratio of toughening agent to foaming agent of 1:(0.01-0.1) can produce products with an impact strength of over 11 J / cm². A more preferred mass ratio is 1:(0.05-0.1). Within this range, the bubble size generated in the diffuser plate is suitable, and the number of bubbles is controlled at 150-270 / cm². 2 Within a certain range, it has a good light diffusion effect while maintaining an impact strength of over 11 J / cm2, exhibiting excellent mechanical properties.

[0054] Example 5

[0055] In this embodiment, all preparation steps and parameters are the same as in Example 1, except that the type of toughening agent is different. Specifically:

[0056]

[0057] The single-layer skin foamed diffusion plate prepared in Example 5 was subjected to performance testing. The specific test results are shown in the table below:

[0058]

[0059]

[0060] As shown in the test data in the table above, the preferred toughening agent in this solution is a composite toughening agent of methyl methacrylate-butadiene-styrene terpolymer and thermoplastic polyurethane. Its compatibility with the foaming agent is good, the bubble size generated within the diffuser plate is appropriate, and the number of bubbles can be controlled at 189 / cm². 2 It has good light diffusion effect and its impact strength can be maintained above 12J / cm2, with good mechanical properties.

[0061] Example 6

[0062] In this embodiment, all preparation steps and parameters are the same as in Example 1, except that the type and ratio of the foaming agent are different. Specifically:

[0063]

[0064] The single-layer skin foamed diffusion plate prepared in Example 6 was subjected to performance testing. The specific test results are shown in the table below:

[0065]

[0066] As shown in the test data in the table above, the preferred foaming agent in this solution is a mixture of sodium bicarbonate, magnesium bicarbonate, and azodicarbonamide. It works well when used in conjunction with the toughening agent, producing bubbles of suitable size within the diffuser plate, and the number of bubbles can be controlled at 186 / cm². 2 It has good light diffusion effect and its impact strength can be maintained above 12J / cm2, with good mechanical properties.

[0067] Example 7

[0068] In this embodiment, all preparation steps and parameters are the same as in Example 1, except that the extrusion die temperature of the extruder is different. Specifically:

[0069] Example 1 220 Example 7-1 210 Example 7-2 230 Example 7-3 240 Example 7-4 250

[0070] The single-layer skin foamed diffusion plate prepared in Example 7 was subjected to performance testing. The specific test results are shown in the table below:

[0071]

[0072] As shown in the test data in the table above, among the preparation parameters, the extruder die temperature of this scheme is more preferably 240℃, which has a better foaming effect, the size of the bubbles generated in the diffuser plate is appropriate, the number of bubbles can be controlled at about 184 / cm2, which has a better light diffusion effect, the impact strength is close to 12J / cm2, and the mechanical properties are better.

[0073] Example 8

[0074] In this embodiment, all preparation steps and parameters are the same as in Example 1. The difference lies in the surface roughness of the embossing roller and the water cooling temperature of the roller. Specifically:

[0075] Example 1 8μm 16μm 20μm 100℃ 100℃ 100℃ Example 8-1 16μm 8μm 20μm 130℃ 100℃ 90℃ Example 8-2 20μm 16μm 8μm 100℃ 100℃ 130℃ Example 8-3 16μm 20μm 8μm 100℃ 130℃ 100℃ Example 8-4 16μm 8μm 20μm 140℃ 130℃ 90℃

[0076] The single-layer skin foamed diffusion plate prepared in Example 8 was subjected to performance testing. The specific test results are shown in the table below:

[0077]

[0078] As shown in the test data in the table above, the polymer melt of this scheme, after being extruded by an extruder, is preferably processed through three-roll forming, with the following parameters: The roughness Ra of the front embossing roll, the middle embossing roll, and the rear embossing roll are preferably: the roughness Ra of the front embossing roll is 10-20 μm, and the roll temperature is 100-140℃; the roughness Ra of the middle embossing roll is 7-12 μm, and the roll temperature is 90-130℃; the roughness Ra of the rear embossing roll is 20-40 μm, and the roll temperature is 70-105℃. At this temperature, the foaming effect is better, and the number of bubbles can be controlled at 150-200 / cm². 2 Within a certain range, the diffuser plate has a large surface area Rz, giving it a frosted appearance and thus a good light diffusion effect.

[0079] Example 9

[0080] A method for preparing a single-layer skin foamed diffusion plate includes the following steps: applying GPPS... 88.25% of the following components are mixed evenly: toughening agent 10% (methyl methacrylate-butadiene-styrene terpolymer and styrene-butadiene-styrene block copolymer in a mass ratio of 1:1); antioxidant pentaerythritol [3-(2,4-di-tert-butylphenyl)propionate] 0.3%; tris(2,4-di-tert-butylphenyl) phosphite 0.3%; organosilicon dispersant 0.5%; foaming agent 0.5% (sodium bicarbonate, magnesium bicarbonate, azodicarbonamide and 2,2'-azobisisobutyronitrile in a mass ratio of 1:0.5:0.2); and nucleating agent (nano silica 0.1% and nano titanium dioxide 0.05%). The mixture is then extruded through an extruder to obtain a polymer melt. The polymer melt is then shaped by an embossing roller, and after cooling, setting and post-treatment, a single-layer skin foamed diffuser plate is obtained.

[0081] The extrusion temperature of the extruder is 190-240℃, and the die temperature of the extruder is 240℃. After the polymer melt is extruded from the extrusion equipment, it passes through the front embossing roller, the middle embossing roller, and the rear embossing roller in sequence for three-roll forming. The roughness Ra of the front embossing roller is 16μm and the roller temperature is 140℃; the roughness Ra of the middle embossing roller is 10μm and the roller temperature is 100℃; the roughness Ra of the rear embossing roller is 20μm and the roller temperature is 105℃.

[0082] The single-layer skin foamed diffusion plate prepared in Example 9 was subjected to performance testing. The specific test results are shown in the table below:

[0083]

[0084] The test results in the table above show that, in terms of formulation, by optimizing the types of toughening agents and foaming agents while strictly limiting the mass ratio of toughening agents to foaming agents; and in terms of manufacturing process, by adjusting the extrusion temperature of the extruder and limiting the specific roughness and roller temperature parameters of the embossing front roller, middle roller, and rear roller, the resulting single-layer skin foamed diffuser plate can achieve an impact strength of over 12 J / cm² even with a thickness reduced to 0.8 mm. Even with a thickness reduced to 0.6 mm, the impact strength can still reach over 9 J / cm², exhibiting excellent mechanical properties. Furthermore, the bubble diameter inside the diffuser plate is 150-190 μm, and the bubble count is 140-260 / cm². 2 It has excellent optical properties.

[0085] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A single-layer skin foamed diffusion plate, characterized in that, The single-layer skin foamed diffusion plate is extruded from the following raw materials by mass percentage: 88-96% plastic substrate, 1-20% toughening agent, 0.1-1% antioxidant, 0.1-1% organosilicon diffusing agent, 0.01-1% foaming agent, and 0.01-0.15% nucleating agent, wherein the mass ratio of the toughening agent to the foaming agent is 1:(0.01-0.1). The thickness of the single-layer skin foamed diffusion plate is 0.6-3.0 mm, and its surface roughness Rz is 20-50 μm.

2. The single-layer skin foamed diffusion plate according to claim 1, characterized in that, The toughening agent includes at least one of styrene-butadiene-styrene block copolymer, styrene-butadiene resin, methyl methacrylate-butadiene-styrene terpolymer, thermoplastic elastomer, or thermoplastic polyurethane.

3. The single-layer skin foamed diffusion plate according to claim 1, characterized in that, The foaming agent includes at least one of sodium bicarbonate, magnesium bicarbonate, calcium carbonate, azodicarbonamide, citric acid, and sodium citrate.

4. The single-layer skin foamed diffusion plate according to claim 1, characterized in that, The nucleating agent includes at least one of magnesium silicate, sodium citrate, sodium oxalate, aluminum oxide, nano silica, nano titanium dioxide, or silicone oil.

5. The single-layer skin foamed diffusion plate according to claim 1, characterized in that, The antioxidants include at least one of butylated hydroxyanisole, butylated hydroxytoluene, tert-butylhydroquinone, diisodecyl phosphite, pentaerythritol diphosphite, bis(2,2,6,6-tetramethylpiperidinyl) sebacate, tris(2,4-di-tert-butylphenyl) phosphite, and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

6. The single-layer skin foamed diffusion plate according to claim 1, characterized in that, The plastic substrate is polystyrene.

7. A method for preparing a single-layer skin foamed diffusion plate as described in any one of claims 1-6, characterized in that, The process includes the following steps: mixing the raw materials of the single-layer skin foamed diffuser plate evenly according to the formula to form a mixture; extruding the mixture through an extrusion device to obtain a polymer melt; the polymer melt is formed by three-roll molding, and then cooled, shaped and post-treated to obtain the single-layer skin foamed diffuser plate. The polymer melt is extruded from the extrusion equipment and then sequentially passes through a front embossing roller, a middle embossing roller, and a rear embossing roller for three-roll forming. The roughness Ra of the front embossing roller is 10-20 μm, and the roller temperature is 100-140℃. The roughness Ra of the middle embossing roller is 7-12 μm, and the roller temperature is 90-130℃. The roughness Ra of the rear embossing roller is 20-40 μm, and the roller temperature is 70-105℃.

8. The method for preparing a single-layer skin foamed diffusion plate according to claim 7, characterized in that, The extrusion temperature of the extrusion equipment is 190-240℃, and the die outlet temperature of the extrusion equipment is 220-250℃.

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