CN103176227B - Light diffusion plate and manufacturing method thereof - Google Patents

Abstract

The invention relates to a light diffusing plate and a preparation method thereof. The composition and mass ratio of the light diffusing plate are: polymethyl methacrylate 90-99.99; light diffusing agent 0.01-10.0. The light diffusing agent is a blend of polystyrene (PSt) and methacryloxypropylphenyl cage oligomeric silsesquioxane (MAPhPOSS). The light diffusion light transmittance and the haze prepared by the invention achieve a good balance, the impact resistance performance is improved, the dimensional stability is good, the uniformity is good, and the processing is easy.

Description

A kind of light diffusion plate and preparation method thereof

technical field

Due to the large power consumption of traditional fluorescent lamps, the operating costs are relatively high. The light diffusion plate can fully diffuse the LED light source. After switching to the LED light source and light diffusion plate, it can save more than 80% of the cost, which meets the requirements of low-carbon and environmental protection in contemporary society. The light diffusion plate is to use the transmitted light to continuously refract, reflect and scatter between the chemical particles and the resin. While covering the light source and the glare light source, it can make the light source emit uniform, soft and beautiful light to achieve light transmission and opacity. comfort effect. It is characterized by sufficient light transmission and light diffusion, and it is a new type of optical material that improves the uniformity of the backlight source through the light scattering effect of the plate, thereby obtaining uniform surface lighting.

Existing technology, Lin Junyu et al [CN1402083A, diffuser plate and its manufacturing method] disclosed diffuser plate, is to be made of transparent substrate (such as acrylic plate, polycarbonate PC plate or glass etc.) and liquid diffusion film through coating And combined by polymerization reaction to form a diffusion plate with a double-layer composite structure. Because the substrate does not have or rarely has the effect of light diffusion, and the light is diffused once through the diffusion film, and because it adopts a coating production method, the flatness of the surface of the diffusion film and the relationship between the diffusion film and the substrate The parallelism is poor, the light diffusion effect is not ideal, and there is no effective countermeasure against the yellowing phenomenon and life reduction of the diffusion plate caused by ultraviolet rays. Dou Xiaoming [CN201859228U, a light diffusion plate] introduces a prism layer and a lens layer as the optical structure layer on the upper and lower layers of the diffusion plate, and uses the principle of refraction and reflection of light to make the diffusion plate have better light transmission and reduce light. Reflection loss, but the use of the prism sheet with the highest cost ratio greatly increases the production cost of the light diffusion plate. [CN101493536A, light diffusion plate and its manufacturing method] in order to reduce the use of prism sheets, a plurality of fine protrusions are hot-pressed on one side of the light diffusion plate and covered with light-collecting thin layers to increase light efficiency, copy The prism structure is used to obtain a prism integrally formed light diffusion structure that has both the functions of a prism sheet and a light diffusion plate. However, after adding a prism structure to the surface of the light diffusion plate, the fine structure (such as a prism structure) on the surface of the light diffusion plate is more likely to be scratched by operators, dust or metal or hard materials such as frames in the subsequent process and damage the product. This further leads to an increase in the defect rate of the overall backlight module. In addition, the diffusion structure with a surface structure can only improve the shading ability, and has limited effect on increasing the brightness of the front. Otherwise, its light extraction efficiency is limited. Hao Yuanzeng et al [CN102219989A, a flame-retardant light-diffusing polycarbonate resin composite material for LED lamps and its preparation method] In order to improve the application range of the product, 2%-5% of organic silicon flame retardant was added to the light-diffusing plate to Improve the flame retardancy of the light diffusion plate and overcome the shortcomings of a single diffuser that is difficult to achieve the balance of haze and light transmittance through the compounding of inorganic and organic light diffusers. Generally, when the light diffusing agent is added to PC or PMMA, the compatibility between the light diffusing agent and the matrix is not good. When the sample is impacted, the scatterer particles fall off from the matrix, and the sample appears brittle fracture, resulting in notched impact strength. When the light diffusion plate is processed and produced, the impact strength of the light diffusion plate decreases and even affects the use (especially the large-area light diffusion plate). Therefore, it is very important to produce a light diffusing plate with excellent light diffusing properties and simultaneously have excellent mechanical properties and processing properties.

Contents of the invention

The invention provides an acrylic light diffusion plate. The light diffusion plate can well solve the low optical efficiency of the existing light diffusion plate, the imbalance of light transmittance and haze, and the poor compatibility of the light diffusion plate caused by the base material and the light diffusion agent. The problems such as the decrease of impact strength are solved, and the prepared light diffusion plate has good dimensional stability and thermal stability, and is easy to process.

The purpose of the present invention is achieved through the following technical solutions:

The acrylic light diffusion plate is characterized in that the composition and mass ratio of the light dispersion plate are:

PMMA 90～99.99

Light diffusing agent 0.01～10

The light diffusing agent is a blend of methacryloxypropylphenyl cage oligomeric silsesquioxane (MAPhPOSS) and polystyrene (PSt), wherein MAPhPOSS accounts for 5% of the total amount of the light diffusing agent ~15%.

The light diffusing agent used in the present invention is mixed in an amount of 0.01 to 10 parts by mass, preferably 0.05 to 8 parts by mass, more preferably 0.1 to 3 parts by mass. When the compounding quantity of a light-diffusion agent is 0.01 mass part or more, light-diffusion property will express and brightness|luminance will raise. When the compounding amount is 10 parts by mass or less, the light diffusivity does not become excessive, and the brightness does not decrease.

The preparation method of the PMMA light diffusion plate is:

Pre-polymerize the monomer MMA in the reactor at 90°C for 10-40 minutes, and cool it for use; add the mixture of the light diffusing agent PSt and MAPhPOSS and the initiator into the prepolymer and stir to dissolve, mix well and add it to the mold, 50-80 After reacting in a water bath at ℃ for 2-4 hours, take it out, bake at high temperature for 2-4 hours, and demould to obtain a PMMA light diffusion plate.

The initiator is azobisisobutyronitrile AIBN.

The advantages of the light diffusion plate are mainly reflected in:

MAPhPOSS, as a new type of nano-organic/inorganic hybrid material, has the advantages of both inorganic light diffusing agents and organic light diffusing agents when added to light diffusing agents, and the multiple benzene ring groups and acrylate groups in MAPhPOSS The group makes MAPhPOSS a two-phase physical crosslinking point similar to a crosslinking network, and has good compatibility with PS and PMMA substrates, which makes the dispersion of PS in PMMA significantly improved, and can obtain uniform light diffusion The dispersion of the plate, the transmittance and haze of the light diffusion plate are balanced, and the impact resistance is improved at the same time. The cage-type siloxane structure and multiple benzene ring groups introduced by the POSS monomer can increase the basic performance of the light diffusion plate, such as flame retardancy and thermal stability, and the prepared light diffusion plate has good dimensional stability and uniformity Good and easy to process. In addition, the use of MAPhPOSS and polystyrene blends as a light diffusing agent also solves the problem that when the traditional PSt microspheres are used as a light diffusing agent, the amount of styrene monomer added is too small to achieve the light-shielding effect, and too much added amount will cause Problems with phase separation creating dark streaks.

Description of drawings

FIG. 1 is a schematic diagram of a light diffusion plate with high light transmittance and high haze in an embodiment of the present invention.

Fig. 2 is a schematic diagram of a light diffusing plate when the amount of light diffusing agent added is too small.

Fig. 3 is a schematic diagram of a light diffusing plate where phase separation occurs when a preferred amount of light diffusing agent is added but MAPhPOSS accounts for too little of the light diffusing agent.

Detailed ways

The objects, advantages and features of the present invention will be explained by the following non-limiting description of preferred embodiments. These embodiments are only typical examples of applying the technical solutions of the present invention, and all technical solutions formed by adopting equivalent replacements or equivalent transformations fall within the protection scope of the present invention.

1. Preparation of PMMA light diffusion plate:

Pre-polymerize the monomer MMA in the reactor at 90°C for 30 minutes, cool it for use; add the mixture of the light diffusing agent PSt and MAPhPOSS and the initiator into the prepolymer, stir and dissolve, mix well, add it to the mold, and react in a water bath at 80°C for 4 hours Finally, take it out, bake at a high temperature of 100°C for 4 hours, and demould to obtain a PMMA light diffusion plate.

Each component can be adjusted by the following weight percentages in the formula:

2. Performance test:

The light transmittance test and the haze test adopt a light transmittance haze meter (produced by Shanghai Precision Scientific Instrument Co., Ltd.) according to the standard ASTM D1003-61 (1997) of the American Society for Experimental Materials, for the light diffusion plate in Examples 1-6 The light transmittance and light diffusibility of the prepared light diffusion plate were tested, and the thickness of the test sample was 2 mm. The test results are shown in the table below.

Claims (3)

1. an acrylic light diffusing sheet, is characterized in that the composition of this light diffusing sheet and mass ratio are:

PMMA 90～99.99；

Light diffusing agent 0.01 ~ 10;

Described light diffusing agent is the blend of methacryloxypropyl phenyl polyhedral oligomeric silsesquioxane (MAPhPOSS) and polystyrene (PSt), and wherein MAPhPOSS accounts for 5% ~ 15% of light diffusing agent total amount.

2. a kind of acrylic light diffusing sheet according to claim 1, is characterized in that described light diffusing agent blending ratio is 0.1 ~ 3 mass parts.

3. the preparation method of PMMA light diffusing sheet according to claim 1, is characterized in that step is as follows:

By monomer M MA 90 DEG C of prepolymerization 10 ~ 40min in a kettle., cool stand-by; The potpourri of light diffusing agent PSt and MAPhPOSS and initiating agent are added stirring and dissolving in prepolymer, add after mixing in mould, after 50 ~ 80 DEG C of water-bath 2 ~ 4h, take out, high-temperature baking 2 ~ 4h, the demoulding, obtains acrylic light diffusing sheet, and described initiating agent is azoisobutyronitrile AIBN.