CN109814187B

CN109814187B - Optical reflection film

Info

Publication number: CN109814187B
Application number: CN201910221053.9A
Authority: CN
Inventors: 罗培栋; 樊华伟
Original assignee: Ningbo Dxc New Material Technology Co ltd
Current assignee: Ningbo Dxc New Material Technology Co ltd
Priority date: 2019-03-22
Filing date: 2019-03-22
Publication date: 2020-11-10
Anticipated expiration: 2039-03-22
Also published as: CN109814187A

Abstract

An optical reflection film comprises a core layer and two surface layers for protecting the core layer, wherein the core layer comprises a main body resin, organic particles incompatible with the main body resin and inorganic particles incompatible with the main body resin; wherein the core layer accounts for 50-90% of the total thickness of the optical reflection film, and the density difference between the organic particles and the main body resin is less than 0.25g/cm³. The density difference between the organic particles of the present invention and the host resin is less than 0.25g/cm³In this case, the organic particles are less likely to aggregate in the host resin, so that the organic particles can be used in a large amount, and the void ratio of the reflective film is increased to some extent.

Description

Optical reflection film

Technical Field

The present invention relates to an optical reflective film.

Background

With the advent of the digital age, Liquid Crystal Display (LCD) technology has become one of the most popular display technologies in use today and will occupy the dominant technical position in the field of flat panel displays for some time. The liquid crystal display generally comprises a liquid crystal panel and a backlight module, wherein the backlight module mainly comprises a light source, a reflective film, a light guide plate, a diffusion film, a brightness enhancement film, an outer frame and other components. The liquid crystal molecules do not emit light themselves, and the image or character displayed by the liquid crystal molecules is the result of modulating light emitted by a backlight source, which is an important component determining the display performance of the liquid crystal, and the brightness of the backlight source directly determines the display brightness of the surface of the LCD. The reflective film is one of the most important optical films in the liquid crystal display, and plays an important role in improving the utilization rate of light energy and saving power consumption.

The principle of manufacturing the reflective film is that organic or inorganic particles having incompatible properties are blended with a main resin, and then the blend is extruded and melted, and a sheet is cast by casting, and during the stretching process, incompatible materials are separated from the main resin to form voids. Because the hollow holes and the resin material have larger refractive index difference, a total reflection interface can be formed in the light irradiation process, and extremely high reflection efficiency is achieved.

Thus, current reflective films increase the reflectivity by increasing the porosity, which is usually achieved by increasing the proportion of incompatible materials, but the proportion of incompatible materials is too high, so that the current method is difficult to be implemented effectively.

Disclosure of Invention

In order to overcome the above-mentioned shortcomings of the existing reflective film, the present invention provides an optical reflective film capable of improving the reflection effect.

The technical scheme for solving the technical problem is that the optical reflecting film comprises a core layer and two surface layers for protecting the core layer, wherein the core layer comprises main body resin, organic particles incompatible with the main body resin and inorganic particles incompatible with the main body resin;

wherein the core layer accounts for 50-90% of the total thickness of the optical reflection film, and the density difference between the organic particles and the main body resin is less than 0.25g/cm³。

Preferably, the difference in surface tension between the organic particles and the host resin is greater than 20 dyn/cm.

Preferably, the host resin is PET, and the organic particles are PMMA particles.

Preferably, the PMMA particles are PMMA particles surface-treated with PTFE.

Preferably, the particle diameter of the PMMA particles is less than 1 μm.

Preferably, the weight percentage of the PMMA particles in the core layer is between 1 percent and 20 percent.

Preferably, the inorganic particles are titanium dioxide particles.

Preferably, the titanium dioxide particles have a particle size of 0.1 to 0.5. mu.m.

Preferably, 90% or more of the titanium dioxide particles are rutile titanium dioxide.

Preferably, the weight percentage of the titanium dioxide particles in the core layer is between 1% and 15%.

The invention has the beneficial effects that: the density difference between the organic particles and the host resin is less than 0.25g/cm³In this case, the organic particles are less likely to aggregate in the host resin, so that the organic particles can be used in a large amount, and the void ratio of the reflective film is increased to some extent.

Detailed Description

The present invention will be described in further detail with reference to specific embodiments.

The optical reflection film comprises a core layer and two surface layers for protecting the core layer, wherein the core layer comprises main resin, organic particles incompatible with the main resin and inorganic particles incompatible with the main resin, and after the core layer is stretched, the organic particles and the main resin and the inorganic particles and the main resin are separated to form cavities.

The core layer accounts for 50-90% of the total thickness of the optical reflection film, namely the total thickness proportion of the two surface layers is 10-50%, if the thickness proportion is less than 10%, the core layer cannot play a role in protection and support, and in the manufacturing process, the core layer is easy to crack, and if the thickness proportion is more than 50%, the reflectivity is too low, and light cannot be effectively reflected.

The density difference between the organic particles and the host resin is less than 0.25g/cm³。

Current reflective films use increased porosity to increase the reflectivity, which is often achieved by increasing the proportion of incompatible materials. However, the incompatible material has a problem of film cracking due to an excessive use ratio, and the applicant has found that the main reason is that the incompatible material for preparing the reflective film has an excessive difference between the density and the matrix resin, and when the difference between the density and the matrix resin is greater than 0.25g/cm³During the process, incompatible materials can form layers in the matrix resin and are gathered together, so that the film is easy to crack in the film-making process. Therefore, the difference in density between the organic particles and the host resin in the present invention is less than 0.25g/cm³In this case, the organic particles are less likely to aggregate in the host resin, so that the organic particles can be used in a large amount, and the void ratio of the reflective film is increased to some extent.

After extensive research by the applicant, it was found that another important factor affecting the void ratio of the optical reflective film is the surface tension between the organic particles and the host resin. When the difference in surface tension between the organic particles and the host resin is greater than 20dyn/cm, the void ratio of the reflective film can be greatly improved.

Main treeThe grease can be PET, PP, PC, PBT, PEN and the like, in the embodiment, the recommended main body resin is PET, the organic particles are PMMA particles, and the density difference between PMMA and PET is less than 0.25g/cm³And the surface tension difference between PMMA and PET is more than 20dyn/cm, and PMMA particles subjected to surface treatment by PTFE are preferred, so that the surface tension difference between PMMA particles and PET main body resin can be further increased. In the present embodiment, the PMMA particle surface-treated with PTFE means that a layer of PTFE is coated on the surface of the PMMA particle.

In order to form sufficiently dense voids, the PMMA particles are recommended to have a particle diameter of 1 μm or less.

In this embodiment, the weight percentage of the PMMA particles in the core layer is between 1% and 20%, the inorganic particles are titanium dioxide particles, and the weight percentage of the titanium dioxide particles in the core layer is between 1% and 15%. Wherein the titanium dioxide particles have a particle size of 0.1 to 0.5 μm to form sufficiently dense cavities, and 90% or more of the titanium dioxide particles are rutile titanium dioxide.

Claims

1. An optical reflection film comprises a core layer and two surface layers for protecting the core layer, wherein the core layer comprises a main body resin, organic particles incompatible with the main body resin and inorganic particles incompatible with the main body resin;

the method is characterized in that: wherein the core layer accounts for 50-90% of the total thickness of the optical reflection film, and the density difference between the organic particles and the main body resin is less than 0.25g/cm³；

The difference in surface tension between the organic particles and the host resin is greater than 20 dyn/cm.

2. The optical reflective film of claim 1, wherein: the main body resin is PET, and the organic particles are PMMA particles.

3. The optical reflective film of claim 2, wherein: the PMMA particles are PMMA particles subjected to surface treatment of PTFE.

4. The optical reflective film of claim 2, wherein: the PMMA particles have a particle diameter of 1 μm or less.

5. The optical reflective film of claim 2, wherein: the weight percentage of the PMMA particles in the core layer is between 1 and 20 percent.

6. The optical reflective film of claim 1, wherein: the inorganic particles are titanium dioxide particles.

7. The optical reflective film of claim 6, wherein: the particle diameter of the titanium dioxide particles is 0.1-0.5 μm.

8. The optical reflective film of claim 6, wherein: more than 90% of the titanium dioxide particles are rutile type titanium dioxide.

9. The optical reflective film of claim 6, wherein: the weight percentage of the titanium dioxide particles in the core layer is between 1 and 15 percent.