CN112937043B

CN112937043B - Light release film for OCA (optical clear adhesive)

Info

Publication number: CN112937043B
Application number: CN202011361081.XA
Authority: CN
Inventors: 吴培服; 吴迪; 王琪; 池卫
Original assignee: Jiangsu Shuangxing Color Plastic New Materials Co Ltd
Current assignee: Jiangsu Shuangxing Color Plastic New Materials Co Ltd
Priority date: 2020-11-28
Filing date: 2020-11-28
Publication date: 2022-04-22
Anticipated expiration: 2040-11-28
Also published as: CN112937043A

Abstract

The invention discloses a light release film for OCA (optical clear adhesive) optical cement, which is used for being attached to one side of an OCA optical cement layer and clamping the OCA optical cement layer with a heavy release film at the other side in the middle, wherein the light release film comprises a release film substrate and a release agent layer coated on the surface of the release film substrate, and the release agent layer is prepared from the following raw materials in parts by weight: 50-80 parts of polydimethylsiloxane, 100-200 parts of ethyl acetate, 10-20 parts of polyurethane resin, 10-20 parts of ethylene-vinyl acetate copolymer, 10-20 parts of tetramethyltetravinylcyclotetrasiloxane, 20-40 parts of tetrahydrofuran and 10-20 parts of terpene resin tackifier. The release agent layer of the invention can obtain continuous release property by slowing down and controlling the seepage speed of release components.

Description

Light release film for OCA (optical clear adhesive)

Technical Field

The application relates to OCA optical cement, especially relates to a from type membrane for OCA optical cement, in particular to a light release type membrane for OCA optical cement.

Background

An OCA (optically Clear adhesive) optical adhesive, also called an OCA optical Clear adhesive, is an optical double-sided adhesive tape formed by bonding a release film on each of the upper and lower surfaces of a substrate-free acrylic adhesive. OCA optical cement is generally used for bonding transparent optical components, such as a touch panel of a mobile phone, a lens and related components thereof.

Fig. 1 shows a schematic structural diagram of an OCA optical adhesive that can be used in the present invention, which includes an intermediate OCA optical adhesive layer 10, wherein the upper surface of the OCA optical adhesive layer 10 is covered with a heavy release film 20, and the lower surface of the OCA optical adhesive layer 10 is covered with a light release film 30. In general, during the preparation, the OCA optical adhesive is first coated on the heavy release film 20, and is cured on the heavy release film 20 to form the OCA optical adhesive layer 10, and then the light release film 30 is attached to the surface of the OCA optical adhesive layer 10, and the OCA optical adhesive layer 10 is sandwiched between the heavy release film 20 and the light release film 30 to keep the surface of the OCA optical adhesive layer 10 flat. When the adhesive tape is used, the light release film 30 is peeled off, the exposed side of the OCA optical adhesive layer 10 is attached to the surface to be bonded, the heavy release film 20 is peeled off, and finally another part to be bonded, such as a mobile phone touch panel, is attached to the outer side of the OCA optical adhesive layer 10.

The heavy release film 20 and the light release film 30 for clamping and protecting the OCA optical adhesive layer 10 belong to release films and have similar release performance. When the heavy release film 20 is used to prepare an OCA optical cement, the heavy release film is first used as a carrier layer of the OCA optical cement, and the OCA optical cement needs to be coated and cured on the surface of the heavy release film 20 to form an OCA optical cement layer. When the light release film 30 is used, it needs to be peeled off in advance. In order to avoid peeling off the light release film 30, the OCA optical adhesive layer will not be pulled away from the surface of the heavy release film 20 along with the light release film 30, so the release force of the light release film 30 is relatively small, and the release force of the heavy release film 20 is relatively large, so as to keep the OCA optical adhesive layer on the surface of the heavy release film 20 during peeling. Of course, the heavy release film 20 is also intended to peel off the surface of the OCA optical adhesive layer, and therefore it is also necessary to ensure that the OCA optical adhesive layer is not pulled off the bonded surface in response to peeling of the heavy release film 20.

For example, CN 111500201 a discloses an OCA optical adhesive and a method for manufacturing the same, wherein the OCA optical adhesive is a three-layer laminated structure, and comprises an OCA transparent film, a heavy-peeling film is coated on the lower surface of the OCA transparent film, and a light-peeling film is coated on the upper surface of the OCA transparent film, wherein the heavy-peeling film and the light-peeling film contain 0.01-3 wt% of UV absorber based on the total weight of each. After UV light irradiation, the transparent film has proper stripping force with the light stripping type film and the heavy stripping type film, and poor stripping and glue tearing can be avoided during stripping.

Although the prior art discloses the OCA optical adhesive, the prior art actually discloses release films on both sides of the OCA optical adhesive, and more specifically discloses a release agent of the release film. However, when the components of the heavy release film and the light release film are provided, only the ratio of the release forces of the heavy release film and the light release film is provided, and how to obtain the release force of the ratio is not clear, but only that the release force can be controlled by adding a control agent, and nothing is explained in detail about the control agent. Thus, the light release film usable for OCA optical adhesives cannot be obtained by those skilled in the art by this prior art.

Disclosure of Invention

The technical problem to be solved by the present application is to provide a light release film for OCA optical cement, so as to reduce or avoid the aforementioned problems.

In order to solve the technical problem, the application provides a light release film for OCA optical cement for attached one side at OCA optical cement layer is with OCA optical cement layer centre gripping in the centre with the heavy release film of opposite side jointly, wherein, light release film is including from type membrane substrate and coating at the release agent layer from the surface of type membrane substrate, wherein, the release agent layer is made for the release agent that is formed by the raw materials preparation of following parts by weight: 50-80 parts of polydimethylsiloxane, 100-200 parts of ethyl acetate, 10-20 parts of polyurethane resin, 10-20 parts of ethylene-vinyl acetate copolymer, 10-20 parts of tetramethyltetravinylcyclotetrasiloxane, 20-40 parts of tetrahydrofuran and 10-20 parts of terpene resin tackifier.

Preferably, the release film substrate is made of a biaxially oriented PET film.

Preferably, the release film substrate is a three-layer co-extruded composite structure polyester film, the three-layer co-extruded composite structure polyester film comprises a surface layer, a bottom layer and a middle layer clamped between the surface layer and the bottom layer, an activated coating is formed on the outer surface of the surface layer of the polyester film, and a release agent layer is formed on the surface of the activated coating by coating the release agent.

Preferably, the surface of the release film substrate for coating the release agent layer forms an activated coating.

In addition, the invention provides a preparation method of the light release film for the OCA optical cement, the light release film is used for being attached to one side of the OCA optical cement layer and clamping the OCA optical cement layer together with the heavy release film on the other side, wherein the light release film comprises a release film substrate and a release agent layer coated on the surface of the release film substrate, and the preparation method of the light release film is characterized by comprising the following steps: adding 10-20 parts by weight of polyurethane resin and 10-20 parts by weight of ethylene-vinyl acetate copolymer into 100-200 parts by weight of ethyl acetate, and stirring for 20-30 minutes; then adding 50-80 parts by weight of polydimethylsiloxane, 10-20 parts by weight of tetramethyltetravinylcyclotetrasiloxane and 20-40 parts by weight of tetrahydrofuran, and stirring for 10-15 minutes; finally, adding 10-20 parts by weight of terpene resin tackifier and stirring for 10 minutes to obtain a release agent; and uniformly coating the release agent on the surface of the release film substrate, curing at 105-110 ℃ for 180 seconds, and curing to form a release agent layer.

In the release agent of the light release film, the ratio of the polyurethane resin and the ethylene-vinyl acetate copolymer is controlled to obtain lighter adhesive force, and the tetrahydrofuran is added to slow down and control the seepage speed of release components, so that the sustained release property can be obtained. In addition, a small amount of added tetramethyl tetravinylcyclotetrasiloxane can be used for generating stronger bonding force with silicon dioxide components in the base film so as to avoid separation of the release layer.

Drawings

The drawings are only for purposes of illustrating and explaining the present application and are not to be construed as limiting the scope of the present application. Wherein the content of the first and second substances,

FIG. 1 shows a schematic diagram of an OCA optical adhesive useful in the present invention;

FIG. 2 is a schematic structural diagram of a light release film for OCA optical cement according to an embodiment of the present application;

FIG. 3 is a schematic structural diagram of a light release film for OCA optical cement according to another embodiment of the present application;

fig. 4 is a schematic structural diagram of a light release film for OCA optical cement according to another embodiment of the present application.

Detailed Description

In order to more clearly understand the technical features, objects, and effects of the present application, embodiments of the present application will now be described with reference to the accompanying drawings. Wherein like parts are given like reference numerals.

As also shown in fig. 1, the present application provides a light release film 30 for OCA optical adhesive, which is attached to one side of an OCA optical adhesive layer 10 and clamps the OCA optical adhesive layer 10 with a heavy release film 20 on the other side.

As described in the background art, the heavy release film 20 and the light release film 30 for holding and protecting the OCA optical adhesive layer 10 are both release films, and both have similar release properties, except that the release force of the light release film 30 is smaller than that of the heavy release film 20.

Fig. 2 is a schematic structural diagram of a light release film for OCA optical adhesive according to an embodiment of the present application. In the embodiment shown in fig. 2, the present invention provides a light release film 30 for OCA optical adhesive, which includes a release film substrate 31 and a release agent layer 32 coated on the surface of the release film substrate 31.

In one embodiment of the present invention, the release agent layer 32 of the present invention is preferably made of release agent prepared from the following raw materials in parts by weight: 50-80 parts of polydimethylsiloxane, 100-200 parts of ethyl acetate, 10-20 parts of polyurethane resin, 10-20 parts of ethylene-vinyl acetate copolymer (EVA 230 of DuPont, U.S.A.), 10-20 parts of tetramethyltetravinylcyclotetrasiloxane, 20-40 parts of tetrahydrofuran and 10-20 parts of terpene resin tackifier. In the release agent, the ratio of the polyurethane resin to the ethylene-vinyl acetate copolymer is controlled to obtain lighter adhesive force, and the tetrahydrofuran is added to slow down and control the seepage speed of release components, so that the sustained release property can be obtained. In addition, a small amount of added tetramethyl tetravinylcyclotetrasiloxane can be used for generating stronger bonding force with silicon dioxide components in the base film so as to avoid separation of the release layer.

The following describes in detail the process for preparing the light release film 30 for OCA optical adhesive according to the present invention by way of specific examples.

Example 1

Adding 10 parts by weight of polyurethane resin and 10 parts by weight of ethylene-vinyl acetate copolymer into 100 parts by weight of ethyl acetate, and stirring for 20-30 minutes; then adding 50 parts by weight of polydimethylsiloxane, 10 parts by weight of tetramethyltetravinylcyclotetrasiloxane and 20 parts by weight of tetrahydrofuran, and stirring for 10-15 minutes; and finally, adding 10 parts by weight of terpene resin tackifier and stirring for 10 minutes to obtain the release agent.

The mold release agent was uniformly applied to the surface of a PET release film substrate 31 having a thickness of 15 μm, cured at 110 ℃ for 180 seconds to form a mold release layer 32, and the thickness of the mold release layer 32 was measured to be 2 μm.

Through detection, the release agent layer 32 of the embodiment has good stability in the range of 120-250 ℃, has no decomposition and separation phenomena, and starts to decompose and separate when the temperature exceeds 250 ℃. The release film of the embodiment has a room temperature release force of 7.25g/25mm for 24 hours and an adhesive force grade of 0, and can be used as a light release film. By contrast, the release agent layer with no tetrahydrofuran had a significantly increased silicone oil leaching rate of 180% or more compared to the present example, and the durability of the release agent layer without tetrahydrofuran was reduced by 55% or more compared to the present example, based on the assumption of the silicone oil content.

Example 2

Adding 20 parts by weight of polyurethane resin and 20 parts by weight of ethylene-vinyl acetate copolymer into 200 parts by weight of ethyl acetate, and stirring for 20-30 minutes; then adding 80 parts by weight of polydimethylsiloxane, 20 parts by weight of tetramethyltetravinylcyclotetrasiloxane and 40 parts by weight of tetrahydrofuran, and stirring for 10-15 minutes; and finally, adding 20 parts by weight of terpene resin tackifier and stirring for 10 minutes to obtain the release agent.

The release agent was uniformly applied to the surface of a PET release film substrate 31 having a thickness of 30 μm, cured at 105 ℃ for 180 seconds to form a release agent layer 32, and the thickness of the release agent layer 32 was measured to be 6 μm.

Through detection, the release agent layer 32 of the embodiment has good stability in the range of 120-250 ℃, has no decomposition and separation phenomena, and starts to decompose and separate when the temperature exceeds 250 ℃. The release film of the embodiment has a room temperature release force of 6.9g/25mm in 24 hours and an adhesive force grade of 0, and can be used as a light release film. By contrast, the release agent layer with no tetrahydrofuran had a silicone oil leaching rate of 190% or more compared to the present example, and the durability of the release agent layer without tetrahydrofuran was reduced by 52% or more compared to the present example, which is presumed from the silicone oil content.

Example 3

Adding 15 parts by weight of polyurethane resin and 15 parts by weight of ethylene-vinyl acetate copolymer into 150 parts by weight of ethyl acetate, and stirring for 20-30 minutes; then adding 65 parts by weight of polydimethylsiloxane, 15 parts by weight of tetramethyltetravinylcyclotetrasiloxane and 30 parts by weight of tetrahydrofuran, and stirring for 10-15 minutes; and finally, adding 15 parts by weight of terpene resin tackifier and stirring for 10 minutes to obtain the release agent.

The release agent was uniformly applied to the surface of a PET release film substrate 31 having a thickness of 25 μm, cured at 110 ℃ for 180 seconds to form a release agent layer 32, and the thickness of the release agent layer 32 was measured to be 5 μm.

Through detection, the release agent layer 32 of the embodiment has good stability in the range of 120-250 ℃, has no decomposition and separation phenomena, and starts to decompose and separate when the temperature exceeds 250 ℃. The release film of the embodiment has a room temperature release force of 7.05g/25mm for 24 hours and an adhesive force grade of 0, and can be used as a light release film. By contrast, the release agent layer with no tetrahydrofuran had a silicone oil leaching rate substantially increased to 185% or more compared to the present example, and the durability of the release agent layer without tetrahydrofuran was reduced by 54% or more compared to the present example, based on the assumption of the silicone oil content.

Further, the present invention improves the structure of the release film substrate 31 compared to the prior art, for example, the present invention forms an activated coating layer 33 on the surface of the release film substrate 31 for coating the release agent layer 32, as shown in fig. 3, which shows a schematic structural view of a release film according to another embodiment of the present application. The purpose of setting up the active coating 33 is used for improving the adhesive force of release agent 32 to do benefit to the combination with the release agent, avoid the silicone oil composition to transfer to OCA optical cement and lead to OCA optical cement to be pulled up the phenomenon.

The release film substrate 31 is preferably made of a biaxially oriented PET film, and may be a single-layer structure as shown in fig. 3, or a multi-layer composite structure as shown in fig. 4, wherein fig. 4 shows a schematic structural diagram of a light release film for OCA optical cement according to another embodiment of the present application. In the embodiment shown in fig. 4, the release film substrate 31 of the present invention is a polyester film with a three-layer co-extrusion composite structure, and the polyester film with the three-layer co-extrusion composite structure may include a surface layer 311, a bottom layer 312 and a middle layer 313 sandwiched therebetween. The washcoat 33 is formed on the outer surface of the skin layer 311 of the mylar film. The release agent is coated on the surface of the activation coating 33 to form a release agent layer 20. The composition of the release film substrate 31 having the single-layer structure shown in fig. 3 is preferably the same as that of the surface layer 311 of the release film substrate 31 having the three-layer co-extruded composite structure shown in fig. 4.

The washcoat 33 of the present invention may comprise the following components: acrylic resin, dimethyl silyl silica surfactant, ethanolamine surface etching agent, polyquaternium surface active bactericide, water-insoluble carbonate, melamine curing agent and propylene glycol solvent.

The ethanolamine surface etching agent can degrade and erode the outer surface of the release film substrate 31 to a certain extent, so that the flatness of the outer surface of the release film substrate 31 is reduced, and the hydrophilic component in the activated coating 33 is favorably and firmly combined with the release film substrate 31; furthermore, ethanolamine is prone to decompose during the coating curing process, which can cause the activated coating 33 to form a fluffy porous structure. The acrylic resin has hydrophilicity, is further emulsified by the dimethylsilylated silica surfactant, and the silicon-containing surfactant and the release film substrate 31 can obtain strong binding force. The polyquaternium surface active bactericide can reduce the surface tension of the cured coating surface, improve the adsorption capacity of the coating to the release agent containing long-chain silane, avoid the release agent from being separated, and the polyquaternium has a sterilization function, so that the release agent layer 32 can be kept in a use state for a long time. Compared with other curing agents, the melamine is not sensitive to moisture and has better affinity with a release agent containing long-chain silane. The water-insoluble carbonate can be selected from calcium carbonate or magnesium carbonate, and is required to avoid reaction with ethanolamine and dissolution in water and other water-soluble components.

In one embodiment, the washcoat 33 of the present invention comprises 80-100 parts by weight of acrylic resin, 1-2 parts by weight of dimethylsilylated silica, 10-15 parts by weight of ethanolamine, 0.5-0.8 parts by weight of polyquaternium, 5-10 parts by weight of water-insoluble carbonate, 1-2 parts by weight of melamine, and 80-100 parts by weight of propylene glycol.

The activated coating of the invention can be prepared by the following steps.

Firstly, uniformly mixing 80-100 parts by weight of acrylic resin, 1-2 parts by weight of dimethyl silylated silica, 10-15 parts by weight of ethanolamine, 0.5-0.8 part by weight of polyquaternary ammonium salt, 5-10 parts by weight of water-insoluble carbonate, 1-2 parts by weight of melamine and 80-100 parts by weight of propylene glycol, coating the mixture on the outer surface of a release film substrate 31 by a spin coating or spray coating mode, and curing at 70-120 ℃ for 1-2 hours, thereby obtaining a precoating layer on the outer surface of the release film substrate 31.

In a specific embodiment, the thickness of the precoat is 5-10 μm, and the water-insoluble carbonate added is preferably calcium carbonate or magnesium carbonate with a particle size of 0.5-1.0 μm.

Thereafter, the precoat layer is subjected to a plasma surface activation treatment. After the surface activation treatment, the surface of the precoat layer forms a uniform rough surface with convex and concave parts, and the water-insoluble carbonate part can be exposed. The plasma surface activation treatment is a common treatment method in the field, and for example, the activation treatment can be carried out by oxygen, the oxygen flow is 100sccm, and the vacuum degree is 0.1-0.2mbar for 30s-60 s.

Then, the precoat layer after the activation treatment is subjected to acid washing. Preferably, the precoat layer is soaked by 6-8mol/L hydrochloric acid at 50-60 ℃ for 10-20 minutes. Through acid washing, the exposed carbonate component on the precoating layer can be partially dissolved, a porous structure can be further obtained, the surface activity of the coating is further improved, and the subsequent close combination with a release agent is facilitated.

Finally, the activated coating 33 of the present invention is obtained by washing with water and drying. Washing with water for 10-20 min, and oven drying at 50-60 deg.C for 30 min.

Through the porous hydrophilic activation coating 33 formed on the surface of the release film substrate 31, the surface activity and the hydrophilicity of the release film substrate 31 are greatly improved, the release film substrate is favorably and tightly combined with the silane containing long chain, and the release agent can be prevented from being separated.

In addition, the invention also provides an improvement on the components of the release film base material 31, so as to provide better adhesion to the release agent layer 20, and simultaneously, the release film base material 31 in the invention has excellent processing performance, good tensile strength and light transmittance and flame retardant property.

Among the release film substrates 31 shown in fig. 3, the release film substrate 31 of the present invention is preferably a PET film containing silica, an alkaline earth metal silicate, and polydimethylsiloxane. Similarly, in the release film substrate 31 shown in fig. 4, the surface layer 311 is preferably a PET film containing silica and an alkaline earth metal silicate and polydimethylsiloxane. The release film substrate 31 shown in fig. 3 will be described in detail below, and those skilled in the art can analogize the above to the surface layer 311 of the release film substrate 31 shown in fig. 4.

In another embodiment, the PET film has a silica content of 0.3 wt% to 1.5 wt%, an alkaline earth metal silicate content of 0.05 wt% to 0.5 wt%, and a polydimethylsiloxane content of 0.2wt% to 1.2 wt%.

The silicon dioxide in the PET film can improve the light transmittance, the processing performance and the strength of the polyester film, and can generate an adsorption effect with a silane component in the activated coating to avoid the activated coating from being separated. The alkaline earth metal silicate, preferably magnesium silicate or calcium silicate, most preferably magnesium silicate, can reduce the heat shrinkability due to the increased silica content of the polyester film. The polydimethylsiloxane can improve the dispersibility of silicon dioxide in the polyester, avoid agglomeration, facilitate the reduction of the addition of inorganic particles and improve the optical performance of the polyester film, and can also generate stronger adhesive force with the dimethyl silylated silica in the activated coating 33.

Silicon atoms of the silicon dioxide and the alkaline earth metal silicate are combined with silicon atoms of the polydimethylsiloxane, and a macromolecule at the other end of the polydimethylsiloxane can be combined with alkane of the polyester, so that the silicon dioxide and the alkaline earth metal silicate can be uniformly dispersed and kept in the polyester. The alkaline earth elements in the alkaline earth metal silicate are easy to form a complex with proper strength and interaction with a common phosphorus compound catalyst, a stabilizer, a flame retardant and the like in the polyester, so that the dispersibility of the silicon dioxide can be improved, the binding force of the silicon dioxide and the alkaline earth metal silicate in the polyester can be improved, and the light transmittance of the polyester film can be improved. In addition, as mentioned above, the addition of an alkaline earth metal silicate such as magnesium silicate or calcium silicate can reduce the shrinkage of the polyester film, and is particularly suitable for addition to a polyester film in the optical field, which is advantageous for improving the optical properties of the base film.

It should be noted that the shrinkage of the polyester film produced by the addition of silica varies significantly, and is very advantageous for heat-shrinkable films. However, for release films, it is desirable to keep the shrinkage of the film at a low level. In the present invention, the combination of the silicate component and the silica improves the dispersibility, and the alkaline earth metal reduces the shrinkage of the film to which the silica is added, thereby improving the optical properties of the film.

In a preferred embodiment, the silica in the PET film is preferably silica aerogel. The silica aerogel is a low-density silica aerogel which is porous and disordered and has a nano-scale continuous network structure, the specific surface area of the silica aerogel is much larger than that of common silica, and phosphate coupling agents and silane coupling agents (such as vinyl triethoxysilane, vinyl trimethoxysilane and vinyl tri (beta-methoxyethoxy) silane) in the prior art are more difficult to disperse than common silica. Because of its very low density, it floats easily and cannot be dispersed into the polyester. The porous structure of the aerogel can generate strong binding force through the polydimethylsiloxane, the density of the aerogel is increased, and the aerogel can be immersed into the polyester. The specific surface area of the alkaline earth metal silicate is also large, the loose and porous characteristic is similar to that of the aerogel, but the dispersibility is better, and the silicon element component of the alkaline earth metal silicate is adsorbed by the aerogel, so that the dispersibility of the aerogel can be improved, and the agglomeration is avoided.

The viscosity of the PET film added with the silicon dioxide or silicon dioxide aerogel, the alkaline earth metal silicate and the polydimethylsiloxane is slightly changed relative to the bulk polyester, so that the stability of the parameters of the polyester film is favorably kept; the dosage of the anti-adhesion particles can be reduced; the processing property, tensile strength, light transmittance and flame retardant property of the polyester film are improved. In addition, the glossiness, the wear resistance, the high temperature resistance and the heat insulation performance of the polyester film can be improved.

In conclusion, in the release agent of the light release film, the ratio of the polyurethane resin to the ethylene-vinyl acetate copolymer is controlled to obtain a light adhesive force, and the tetrahydrofuran is added to slow down and control the seepage speed of release components, so that the sustained release property can be obtained. In addition, a small amount of added tetramethyl tetravinylcyclotetrasiloxane can be used for generating stronger bonding force with silicon dioxide components in the base film so as to avoid separation of the release layer.

It should be appreciated by those skilled in the art that while the present application is described in terms of several embodiments, not every embodiment includes only a single embodiment. The description is thus given for clearness of understanding only, and it is to be understood that all matters in the embodiments are to be interpreted as including all technical equivalents which are encompassed by the claims and are to be interpreted as combined with each other in a different embodiment so as to cover the scope of the present application.

The above description is only illustrative of the present invention and is not intended to limit the scope of the present invention. Any equivalent alterations, modifications and combinations that may be made by those skilled in the art without departing from the spirit and principles of this application shall fall within the scope of this application.

Claims

1. The utility model provides a light from type membrane for OCA optical cement for attached one side on OCA optical cement layer, with the heavy type membrane of opposite side with OCA optical cement layer centre gripping in the centre jointly, wherein, light from type membrane is including from type membrane substrate and coating at the release agent layer from the surface of type membrane substrate, its characterized in that, the release agent layer is made for the release agent that is prepared by the raw materials of following parts by weight: 50-80 parts by weight of polydimethylsiloxane, 100-200 parts by weight of ethyl acetate, 10-20 parts by weight of polyurethane resin, 10-20 parts by weight of ethylene-vinyl acetate copolymer, 10-20 parts by weight of tetramethyltetravinylcyclotetrasiloxane, 20-40 parts by weight of tetrahydrofuran and 10-20 parts by weight of terpene resin tackifier; wherein the release film base material is made of a biaxially oriented PET film; the surface of the release film substrate, which is used for coating a release agent layer, forms an activated coating; the activated coating comprises 80-100 parts by weight of acrylic resin, 1-2 parts by weight of dimethyl silyl silica, 10-15 parts by weight of ethanolamine, 0.5-0.8 part by weight of polyquaternium, 5-10 parts by weight of water-insoluble carbonate, 1-2 parts by weight of melamine and 80-100 parts by weight of propylene glycol; the PET film contains 0.3-1.5 wt% of silicon dioxide aerogel, 0.05-0.5 wt% of alkaline earth metal silicate and 0.2-1.2 wt% of polydimethylsiloxane.

2. The method for preparing a light release film for an OCA optical cement according to claim 1, wherein the light release film is used for being attached to one side of an OCA optical cement layer and clamping the OCA optical cement layer with a heavy release film at the other side, and the light release film comprises a release film substrate and a release agent layer coated on the surface of the release film substrate, and the method for preparing the light release film comprises the following steps: adding 10-20 parts by weight of polyurethane resin and 10-20 parts by weight of ethylene-vinyl acetate copolymer into 100-200 parts by weight of ethyl acetate, and stirring for 20-30 minutes; then adding 50-80 parts by weight of polydimethylsiloxane, 10-20 parts by weight of tetramethyltetravinylcyclotetrasiloxane and 20-40 parts by weight of tetrahydrofuran, and stirring for 10-15 minutes; finally, adding 10-20 parts by weight of terpene resin tackifier and stirring for 10 minutes to obtain a release agent; and uniformly coating the release agent on the surface of the release film substrate, curing at 105-110 ℃ for 180 seconds, and curing to form a release agent layer.

3. The method of claim 2, further comprising the step of preparing the washcoat: firstly, uniformly mixing 80-100 parts by weight of acrylic resin, 1-2 parts by weight of dimethyl silylated silica, 10-15 parts by weight of ethanolamine, 0.5-0.8 part by weight of polyquaternary ammonium salt, 5-10 parts by weight of water-insoluble carbonate, 1-2 parts by weight of melamine and 80-100 parts by weight of propylene glycol, coating the mixture on the outer surface of a release film substrate by a spin coating or spray coating mode, and curing at 70-120 ℃ for 1-2 hours to obtain a precoating layer on the outer surface of the release film substrate; then, carrying out plasma surface activation treatment on the precoat layer; then, carrying out acid cleaning on the precoat after the activation treatment; finally, washing and drying with water to obtain the activated coating.