CN114716967A

CN114716967A - Organic silicon elastomer, organic silicon OCA optical cement, and preparation method and application thereof

Info

Publication number: CN114716967A
Application number: CN202210275531.6A
Authority: CN
Inventors: 佘友智; 黄志坚
Original assignee: Guangdong Zaicheng New Material Co ltd
Current assignee: Guangdong Zaicheng New Material Co ltd
Priority date: 2022-03-21
Filing date: 2022-03-21
Publication date: 2022-07-08

Abstract

The invention provides an organic silicon elastomer, an organic silicon OCA optical cement, and a preparation method and application thereof. The raw material formula of the organic silicon elastomer comprises polysiloxane, prepolymer containing vinyl side chains and a cross-linking agent; the weight ratio of the polysiloxane to the prepolymer containing the vinyl side chain is 1: 7-7: 1; the vinyl content of the prepolymer containing vinyl side chains is 60 to 90 percent; the weight average molecular weight of the prepolymer containing vinyl side chains is less than 8000 g/mol. Organosilicon OCA optical cement includes from the first type membrane, above-mentioned organosilicon elastomer layer and the second of stacking gradually the setting from bottom to top from the type membrane. According to the invention, through the crosslinking reaction and curing of the prepolymer containing the vinyl side chain, the polysiloxane and the crosslinking agent, the organic silicon elastomer has excellent optical capability and good non-deformation characteristic, and can effectively prevent the meshes of the backlight plate from being blocked, so that light can effectively penetrate through the backlight meshes, and the backlight intensity is increased.

Description

Organic silicon elastomer, organic silicon OCA optical cement, and preparation method and application thereof

Technical Field

The invention relates to the technical field of optical cement, in particular to an organic silicon OCA optical cement, and specifically relates to an organic silicon elastomer, an organic silicon OCA optical cement, and a preparation method and an application thereof.

Background

The OCA optical cement is an optical element bonding material with multiple excellent performances. OCA optical Adhesive (optical Clear Adhesive) is a special Adhesive used for gluing transparent optical elements (such as display cover plates, touch panels, etc.). In general, OCA refers to a double-sided adhesive product in which an optical acrylic pressure-sensitive adhesive is made into a substrate-free adhesive film, and then a release film is respectively attached to an upper bottom layer and a lower bottom layer. As one of important raw materials of the touch screen, the OCA optical cement is mainly applied to material adhesion of the touch screen, has the effect of capacitive touch sensing, has the characteristics of high clarity, strong light transmittance (the light transmittance is more than 90%), high adhesion, water resistance, high temperature resistance, ultraviolet resistance, good cementing strength, capability of being used at room temperature or at intermediate temperature, small curing shrinkage and the like. OCA optical cement is used for bonding of the touch screen module and bonding of the touch screen and the display screen, so that the screen is clearer, thinner, smoother and more durable.

When current LCM screen utilizes OCA full laminating, because of OCA belongs to soft material, have great filling performance and higher deformability, when laminating with the board in a poor light, the mesh that leads to the board in a poor light easily in the laminating process all is filled by OCA, and then leads to the luminance reduction in a poor light.

At present, patent CN111154430A discloses an ultraviolet curing type OCA pressure-sensitive adhesive film and a preparation method thereof, the type is prepared by using an acrylate adhesive, and the acrylate adhesive has poor weather resistance, is easy to degrade and break, is yellowed or cracked after aging in the use process in many scenes due to the low C-C bond energy relative to the Si-O bond energy of organic silicon, and cannot meet the diversified application at present. CN104004460A discloses an organic silicon gel optical adhesive film and a production process thereof, the type adopts a two-component thermosetting organic silicon adhesive, and in the preparation of an OCA adhesive film, due to the need of mixing two components, the equipment investment is large, the large-scale production can not be carried out, and the scrapping of the gel of the adhesive solution is easy to cause, thereby greatly influencing the production efficiency.

Therefore, it is urgently needed to develop an organic silicon OCA optical cement which can effectively prevent the mesh of the backlight plate from being blocked, so that light can effectively penetrate through the backlight mesh and the backlight intensity is increased.

Disclosure of Invention

The invention aims to make up the defects of the prior art and provides a silicone elastomer, a silicone OCA optical cement, and preparation methods and applications thereof.

By means of the excellent long-term weather resistance, lower shrinkage, excellent optical performance, lower dielectric constant and other excellent performances of the organic silicon, the organic silicon OCA optical adhesive disclosed by the invention is easy to coat, fast to cure, high in bonding yield and reworkable, so that the OCA organic silicon optical adhesive bonding scheme is adopted by more and more display factories. The invention can effectively prevent the mesh of the backlight plate from being blocked mainly by the excellent optical capability and good non-deformation characteristic of the organic silicon elastomer, so that light can effectively penetrate through the backlight mesh to increase the backlight light intensity.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides a silicone elastomer, wherein the raw material formula of the silicone elastomer comprises polysiloxane, prepolymer containing vinyl side chain and cross-linking agent; the weight ratio of the polysiloxane to the prepolymer containing the vinyl side chain is 1: 7-7: 1, preferably 2: 1-6: 1.

The polysiloxane comprises one or more of polymethylvinylsiloxane, polyvinyl tri (trimethylsiloxy) silane, polytetramethyl divinyl disiloxane, polytetramethyl tetravinyl cyclotetrasiloxane, poly 1, 3-divinyl-1, 3-dimethyl-1, 3-diphenyl disiloxane and poly 1, 3-dimethyl-1, 1,3, 3-tetraene disiloxane.

The prepolymer containing vinyl side chains comprises one or more of polydimethylsiloxane, cyclomethicone, aminosiloxane, polymethylphenylsiloxane and polyether polysiloxane copolymer containing vinyl side chains; the vinyl content of the prepolymer containing vinyl side chains is 60 to 90 percent, preferably 70 to 85 percent; the weight average molecular weight of the prepolymer containing vinyl side chains is less than 8000 g/mol.

The cross-linking agent is one of dicumyl peroxide, benzoyl peroxide and dicumyl hydroperoxide; the weight ratio of the cross-linking agent to the polysiloxane is in the range of 10% to 30%, preferably 15% to 25%.

The elastic modulus of the organic silicon elastomer is 5-8 MPa; tensile strength is 3000-4000/kg.m 2; the light transmittance is not less than 90 percent; haze is not more than 1%; the surface energy is 15-25 mN/m; the elongation is lower than 45%.

In a second aspect, the present invention provides a use of the silicone elastomer of the first aspect in a silicone OCA optical cement.

Organosilicon OCA optical cement includes from the first type membrane, organosilicon elastomer layer and the second of stacking gradually the setting from bottom to top from the type membrane.

Preferably, the thickness of the organic silicon elastomer is 150-250 um, the thickness of the first release film is 30-80 um, and the thickness of the second release film is 70-140 um.

Preferably, the release force of the first release film is 3-5 g; the second release film has a release force of 25-30 g.

In a third aspect, the present invention provides a method for preparing the silicone OCA optical cement according to the second aspect, wherein the method comprises the following steps:

step (1): uniformly mixing the raw materials of the organic silicon elastomer to obtain the organic silicon mixed solution, and removing bubbles in the organic silicon mixed solution at the pressure of 3-5 Kg for 10-20 min.

Step (2): the first release film is flatly laid, then the organic silicon mixed solution is coated on the first release film according to the specified thickness by using a scraper or an optical coating machine, and then the organic silicon elastomer is cured for 1-3 hours at the temperature of 60-80 ℃.

And (3): after curing is completed, the second release film is laid on the cured silicone elastomer layer.

In a fourth aspect, the present invention provides a use of the silicone elastomer according to the first aspect or the silicone OCA optical cement according to the second aspect in an electronic display screen, preferably as a filling double-sided adhesive layer between a touch screen and a display screen.

In a fifth aspect, the present invention provides a bonding process of the silicone OCA optical cement according to the second aspect, including the following steps:

step (1): and removing the release film on the binding surface of the organic silicon OCA optical cement, and arranging the release film on a first carrying platform of the binding jig.

Step (2): and treating the surface of the organic silicon elastomer layer of the organic silicon OCA optical cement by using a surface treating agent to enable the surface to have certain viscosity.

And (3): and placing the piece to be attached on a second carrying platform in the attaching jig, and attaching the piece to be attached in close contact with the treated organic silicon elastomer layer.

The surface treating agent in the step (2) comprises 63.5-67.5 wt% of vinyl trimethoxy silane, 30-32.4 wt% of allyl trimethoxy silane and 0.1-2.5 wt% of catalyst; preferably, the catalyst is selected from tetrabutyl titanate.

Compared with the prior art, the technical scheme of the invention has the following beneficial effects:

(1) the organic silicon elastomer has excellent mechanical property and optical property, and particularly has the elastic modulus of 5-8 MPa; tensile strength of 3000-4000/kg.m²(ii) a The light transmittance is not less than 90 percent; haze is not more than 1%; the surface energy is 15 to 25 mN/m. According to the invention, through the crosslinking reaction and curing of the prepolymer containing the vinyl side chain, the polysiloxane and the crosslinking agent, the organic silicon elastomer has excellent optical capability and good non-deformation characteristic, the mesh of the backlight plate is effectively prevented from being blocked, light effectively penetrates through the backlight mesh, and the backlight intensity is increased.

(2) The organic silicon OCA optical adhesive solves many defects and limitation problems of the traditional OCA, and by means of excellent long-term weather resistance, lower shrinkage, excellent optical performance, lower dielectric constant and other excellent performances of organic silicon, easy coating, fast curing, high bonding yield and reworkability, the organic silicon OCA optical adhesive bonding scheme is adopted by more and more display factories.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention.

In the drawings:

FIG. 1 shows a schematic view of a silicone OCA optical cement provided according to an embodiment of the present invention;

wherein the figures include the following reference numerals: 1 is a first release film; 2 is a silicone elastomer layer; and 3 is a second release film.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs.

As the analysis of the background art of the application, OCA optical cement is because its great filling performance and higher deformability, when laminating with the board in a poor light, leads to the mesh of board in a poor light easily to all be filled by OCA in the laminating process, and then leads to the luminance reduction in a poor light. In order to solve the problem, the application provides an organic silicon elastomer, an organic silicon OCA optical cement, and a preparation method and application thereof.

In one exemplary embodiment herein, a silicone elastomer is provided, the silicone elastomer having a raw material formulation comprising a polysiloxane, a vinyl side chain-containing prepolymer, and a crosslinking agent; the weight ratio of the polysiloxane to the prepolymer containing the vinyl side chain is 1: 7-7: 1, preferably 2: 1-6: 1. For example, 3:1, 5:2, 7:2, 4:1, 9:2, 5:1, 11:2, etc. may be used. But are not limited to, the above-listed values or alternatives, other values or alternatives not listed within the above-mentioned range of values or alternatives are equally applicable. The specific composition ratio can further improve the optical property and the tensile resistance of the silicone elastomer. When the weight ratio of the polysiloxane to the prepolymer containing the vinyl side chain is less than 1:7, the obtained silicone elastomer is bonded with a backlight plate due to the large filling performance and the high deformability, and simultaneously, meshes of the backlight plate are easily filled with OCA in the bonding process; when the weight ratio range of the polysiloxane to the prepolymer containing the vinyl side chain is more than 7:1, the obtained silicone elastomer has poor tensile property and mechanical property which does not meet the requirement. The weight ratio of the polysiloxane to the prepolymer containing the vinyl side chain is preferably 2: 1-6: 1, and within the range, the obtained organic silicon elastomer has high light transmittance, low haze, better tensile property and enough deformation resistance.

In a typical embodiment herein, the polysiloxane comprises one or more of polymethylvinylsiloxane, polyvinyltris (trimethylsiloxy) silane, polytetramethylenedivinyldisiloxane, polytetramethylenecyclotetrasiloxane, poly 1, 3-divinyl-1, 3-dimethyl-1, 3-diphenyldisiloxane, poly 1, 3-dimethyl-1, 1,3, 3-tetraenedisiloxane. Because the Si-O unit has lower surface energy (21-22Mn/m), the free energy of the organic silicon OCA optical cement can be reduced, and the annular adhesive force and the release force are obviously increased aiming at the interface with low surface energy.

The prepolymer containing the vinyl side chain comprises one or more of polydimethylsiloxane containing the vinyl side chain, cyclomethicone, aminosiloxane, polymethylphenylsiloxane and polyether polysiloxane copolymer; the vinyl side chain-containing prepolymer has a vinyl content of 60% to 90%, preferably 70% to 85%, for example, the vinyl content may be 72%, 75%, 76%, 78%, 80%, 82%, 83%, 84%. But are not limited to, the above-listed values or alternatives, other values or alternatives not listed within the above-mentioned range of values or alternatives are equally applicable. The prepolymer containing the vinyl side chain contains a reactive functional group, and can perform a faster crosslinking reaction with polysiloxane under the action of a crosslinking agent, so that the curing efficiency of the obtained organic silicon elastomer is improved; the vinyl content is in the range of 60-90%, so that the molecules have higher bonding strength, and the integral elastic modulus and tensile strength of the organic silicon elastomer are improved. The weight average molecular weight of the prepolymer containing the vinyl side chain used in the invention is lower than 8000g/mol, and compared with a high molecular compound, the prepolymer has lower steric hindrance and is easier to generate a crosslinking reaction with polysiloxane. When the weight average molecular weight of the prepolymer containing the vinyl side chain is higher than 8000g/mol, the viscosity of the polymer is increased along with the increase of the molecular weight, but when the molecular weight of the prepolymer containing the vinyl side chain is too large, the molecular chain wraps hydroxyl groups, so that hydrophilic groups of polysiloxane cannot be combined with the prepolymer containing the vinyl side chain, the compatibility of the polysiloxane and the prepolymer containing the vinyl side chain is hindered, and the mechanical property of the organic silicon elastomer is influenced.

In the examples of the present application, the role of the crosslinking agent is to generate a diradical, forming a bridge between the polymer molecular chains, forming an insoluble substance of a three-dimensional structure. The kind of the crosslinking agent is not particularly limited in the present invention, and preferably, at least one of dicumyl peroxide, benzoyl peroxide, and dicumyl hydroperoxide; the weight ratio of the crosslinking agent to the polysiloxane is in the range of 10% to 30%, preferably 15% to 25%, and may be, for example, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 24%, or the like. When the cross-linking agent is in the above weight range of the polysiloxane, the obtained silicone elastomer has higher elastic modulus and tensile strength, the weight ratio of the cross-linking agent to the polysiloxane is lower than 10%, the modulus of the silicone elastomer is lower than the use requirement, the deformation resistance of the elastomer material is insufficient, and the backlight mesh is easy to fill in the fitting process, so that the backlight brightness is reduced; the weight ratio of the cross-linking agent to the polysiloxane is higher than 30%, the cross-linking agent is excessive, on one hand, the cost is increased, and on the other hand, the excessive cross-linking agent can overflow to affect the cleanness of the surface of the organic silicon OCA optical cement.

In the embodiment of the application, the elastic modulus of the organic silicon elastomer is 5-8 MPa; tensile strength is 3000-4000/kg.m 2; the light transmittance is not less than 90 percent; haze is not more than 1%; the surface energy is 15-25 mN/m; the elongation is lower than 45%. While silicone elastomers exhibit excellent adhesion.

Organosilicon OCA optical cement includes from the first type membrane, organosilicon elastomer layer and the second of stacking gradually the setting from bottom to top from the type membrane. Particularly, the three-layer attached thickness of the organic silicon OCA optical adhesive endows the optical adhesive with excellent adhesion performance.

In a preferred embodiment of the present invention, the silicone elastomer has a thickness of 150 to 250um, and may be, for example, 160 μm, 180 μm, 200 μm, 220 μm, 240 μm, or the like. The thickness of the first release film is 30-80 um, and can be 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, and the like. The thickness of the second release film is 70-140 um, such as 80 μm, 100 μm, 120 μm, 140 μm

In a preferred embodiment of the present invention, the first release film has a release force of 3 to 5g, and may be, for example, 3 g, 3.5 g, 4 g, 4.5 g, 5g, or the like.

In a preferred embodiment of the present invention, the second release film has a release force of 25 to 30g, for example, 25 g, 26 g, 27 g, 28 g, 29 g, 30g, etc.

In a preferred embodiment of the present invention, the surface of the second release film is corona-treated, and the outermost layer is not easily separated, so that the silicone OCA optical adhesive of the present invention can be better protected. The principle of the corona treatment is that high-frequency high-voltage is utilized to carry out corona discharge on the surface of the treated plastic (the high-frequency alternating-current voltage reaches 5000-²) The surface is roughened and the wettability to polar solvents is increased-these plasmas damage their molecular structure by electric shock and penetration into the surface of the body to be printed, which in turn oxidizes and polarizes the surface molecules to be treated, the electric shock attacks the surface, so as to increase the adhesion capacity of the surface of the printing material. The corona treatment rearranges the molecular structure of the surface of the printing stock to generate more polar parts, which is beneficial to the attachment of foreign matters.

In a preferred embodiment of the present application, the first release film and the second release film are independently selected from any one of a PET release film, a PE release film, an OPP release film, a BOPET release film and a BOPP release film.

And (3): and after the curing is finished, the second release film is laid on the cured organic silicon elastomer layer.

In a fourth aspect, the present invention provides a use of the silicone elastomer according to the first aspect or the silicone OCA optical cement according to the second aspect in an electronic display screen, preferably used as a filling double-sided adhesive between a touch screen and a display screen. The Si-O bond in the organic silicon OCA optical cement has high energy, excellent weather resistance and unique spatial arrangement, can adapt to wider temperature change, and meets the application requirements of different fields.

And (3): and placing the piece to be attached on a second carrying platform in the attaching jig, and attaching the piece to be attached in close contact with the processed organic silicon elastomer layer.

The present application is described in further detail below with reference to specific examples, which should not be construed as limiting the scope of the invention as claimed.

Example 1

The embodiment provides a silicone elastomer, which comprises the following raw materials in parts by weight: 65 parts by weight of a polysiloxane, 20 parts by weight of a polydimethylsiloxane containing vinyl side chains (weight-average molecular weight 5000g/mol, vinyl content 80%) and 15 parts by weight of a crosslinking agent dicumyl peroxide.

The raw materials are uniformly mixed to obtain the organic silicon mixed liquid, bubbles in the organic silicon mixed liquid are removed within 15min within the pressure range of 4Kg, a first release film (with the thickness of 50um and the release force of 5g) is tiled, then the organic silicon mixed liquid is coated on the first release film by using a scraper, the thickness of an organic silicon elastomer is 200 mu m, then the organic silicon elastomer is cured for 2 hours at 70 ℃, and after the curing is finished, a second release film (with the thickness of 100um and the release force of 30g) is tiled on the cured organic silicon elastomer layer to obtain the organic silicon OCA optical cement.

The organic silicon OCA optical adhesive is applied between a touch screen and a display screen of a liquid crystal display screen to serve as a filling double-sided adhesive, when the organic silicon OCA optical adhesive is used, the release film on the bonding surface of the organic silicon OCA optical adhesive is removed, and the release film is placed on a first carrying table of the bonding jig; treating the surface of the material by using a surface treating agent (65.5 percent of vinyl trimethoxy silane, 32 percent of allyl trimethoxy silane and 2.5 percent of tetrabutyl titanate) to enable the material to have certain viscosity; and placing the piece to be attached on a second carrying platform in the attaching jig, and attaching the piece to be attached to the organic silicon elastomer layer which is in close contact with the processed organic silicon elastomer layer and a backlight plate of the liquid crystal display screen.

Example 2

Example 2 differs from example 1 in that the weight percentage of the polysiloxane to the vinyl side chain-containing polydimethylsiloxane (vinyl content 80%) is 5: 1.

Example 3

Example 3 differs from example 1 in that the weight percentage of the polysiloxane to the vinyl side chain-containing polydimethylsiloxane (vinyl content 80%) is 1: 7.

Example 4

Example 4 differs from example 1 in that the weight percentage of polysiloxane to vinyl side chain-containing polydimethylsiloxane (vinyl content 80%) is 7: 1.

Example 5

Example 5 differs from example 1 in that the weight percentage of the polysiloxane to the vinyl side chain-containing polydimethylsiloxane (vinyl content 80%) is 1: 2.

Example 6

Example 6 differs from example 1 in that the weight percentage of polysiloxane to vinyl side chain-containing polydimethylsiloxane (vinyl content 80%) is 2: 1.

Example 7

Example 7 differs from example 1 in that the vinyl side chain-containing polydimethylsiloxane has a vinyl content of 60%.

Example 8

Example 8 differs from example 1 in that the vinyl side chain-containing polydimethylsiloxane has a vinyl content of 90%.

Example 9

Example 9 differs from example 1 in that the vinyl side chain-containing polydimethylsiloxane has a vinyl content of 70%.

Example 10

Example 10 differs from example 1 in that the vinyl side chain-containing polydimethylsiloxane had a vinyl content of 85%.

Example 11

Example 11 differs from example 1 in that the weight average molecular weight of the vinyl side chain-containing polydimethylsiloxane is 8000 g/mol.

Example 12

Example 12 differs from example 1 in that the vinyl side chain-containing oligomer is a vinyl side chain cyclomethicone.

Example 13

Example 13 differs from example 1 in that the vinyl side chain-containing oligomer is a vinyl side chain aminosiloxane.

Example 14

Example 14 differs from example 1 in that the weight ratio of the cross-linking agent to the polysiloxane was 10%.

Example 15

Example 15 differs from example 1 in that the weight ratio of the cross-linking agent to the polysiloxane was 30%.

Example 16

Example 16 differs from example 1 in that the silicone elastomer layer thickness is 150 μm, the first release film thickness is 80um, and the second release film thickness is 130 um.

Example 17

Example 17 differs from example 1 in that the silicone elastomer layer thickness is 250 μm, the first release film thickness is 30um, and the second release film thickness is 80 um.

Example 18

Example 18 differs from example 1 in that the surface treatment agent was 67% vinyltrimethoxysilane, 32% allyltrimethoxysilane, and 1% tetrabutyl titanate.

Comparative example 1

Comparative example 1 differs from example 1 in that the weight percentage of the polysiloxane to the vinyl side chain-containing polydimethylsiloxane (vinyl content 80%) is 8: 1.

Comparative example 2

Comparative example 2 differs from example 1 in that the weight percentage of the polysiloxane to the vinyl side chain-containing polydimethylsiloxane (vinyl content 80%) was 1: 8.

Comparative example 3

Comparative example 3 is different from example 1 in that the weight average molecular weight of the polydimethylsiloxane containing a vinyl side chain is 10000 g/mol.

Comparative example 4

Comparative example 4 differs from example 1 in that the vinyl side chain-containing polydimethylsiloxane was replaced with a vinyl terminated dimethylpolysiloxane.

Comparative example 5

Comparative example 5 is different from example 1 in that the vinyl side chain-containing polydimethylsiloxane has a vinyl content of 50%.

Comparative example 6

Comparative example 5 is different from example 1 in that the vinyl side chain-containing polydimethylsiloxane has a vinyl content of 95%.

Performance testing

The silicone elastomers obtained by the above examples 1 to 18 and comparative examples 1 to 6 were evaluated by the following test methods.

(1) Light transmittance test standard: GB/T2410-.

(2) Haze test standard: GB/T2410-.

(3) Elastic modulus test standard: JB/T6544-93.

(4) Tensile strength test standard: GB/T31541-2015.

(5) The surface energy test method comprises the following steps: contact angle between the OCA film and the substrate was measured using a contact angle goniometer (Phoenix 300, Surface & Electro-Optics, Korea). Distilled water and diiodomethane were dropped on the samples, and after 5 seconds of stabilization, the contact angle obtained the value for each sample, and the process was repeated three times. The temperature is 24 +/-1 ℃, and the relative humidity is 50 +/-2%. The free energy of each sample on the surface was calculated using the Owens-Wendt method.

(6) Elongation test standard: GB/T1701-2001.

The results of the specific tests of the examples and comparative examples are shown in table 1:

TABLE 1

From the above test results it can be seen that: as can be seen from the comparison of the test results of example 1 with those of comparative examples 1 and 2, when the weight ratio of the polysiloxane to the prepolymer containing vinyl side chains is less than 1:7, the silicone elastomer obtained has a large filling property and a high deformability, and is easy to cause the meshes of the backlight panel to be filled with OCA during the lamination process while being laminated with the backlight panel; when the weight ratio range of the polysiloxane to the prepolymer containing the vinyl side chain is more than 7:1, the obtained silicone elastomer has poor tensile property and mechanical property which does not meet the requirement. Within the range of 1: 7-7: 1, the obtained organic silicon elastomer has high light transmittance, low haze and better tensile resistance, and has enough deformation resistance.

As can be seen from the comparison of the test results of example 1 with comparative examples 5 and 6, when the vinyl content of the polydimethylsiloxane containing vinyl side chains is less than 60%, the modulus of the silicone elastomer is lower than the use requirement, the elastomeric material has insufficient deformation resistance, and the backlight mesh is easily filled during the fitting process, resulting in the decrease of the backlight brightness; the vinyl content of the polydimethylsiloxane containing the vinyl side chain is higher than 90%, and gel is easily formed in the preparation process.

As can be seen from the comparison of the test results of example 1 and comparative example 3, when the weight average molecular weight of the polydimethylsiloxane containing vinyl side chains is higher than 8000g/mol as described herein, the obtained silicone elastomer has low elastic modulus, low tensile strength and high elongation.

As can be seen from a comparison of the test results of example 1 and comparative example 4, when the vinyl side chain-containing polydimethylsiloxane was replaced with a vinyl-terminated dimethylpolysiloxane, the tensile strength of the resulting silicone elastomer was low due to the lower vinyl content.

The above-described embodiments of the present invention achieve the following technical effects: the organic silicon elastomer obtained by the embodiment of the invention has excellent optical capability and good non-deformation characteristic, and can effectively prevent the meshes of the backlight plate from being blocked, so that light can effectively penetrate through the backlight meshes, and the backlight intensity is increased. The elastic modulus of the obtained organic silicon elastomer is 5-8 MPa; the tensile strength is 3000-4000/kg.m²(ii) a The light transmittance is not less than 90 percent; haze is not more than 1%; the surface energy is 15-25 mN/m; the elongation is lower than 45%.

The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core ideas. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

Claims

1. The silicone elastomer is characterized in that the raw material formula of the silicone elastomer comprises polysiloxane, prepolymer containing vinyl side chains and a crosslinking agent; the weight ratio of the polysiloxane to the prepolymer containing the vinyl side chain is 1: 7-7: 1, preferably 2: 1-6: 1.

2. The silicone elastomer of claim 1, wherein the polysiloxane comprises one or more of polymethylvinylsiloxane, polyvinyltris (trimethylsiloxy) silane, polytetramethylenedivinyldisiloxane, polytetramethylenecyclotetrasiloxane, poly 1, 3-divinyl-1, 3-dimethyl-1, 3-diphenyldisiloxane, poly 1, 3-dimethyl-1, 1,3, 3-tetraethylenedisiloxane.

3. The silicone elastomer of claim 1, wherein the vinyl side chain-containing prepolymer comprises one or more of a vinyl side chain-containing polydimethylsiloxane, a cyclomethicone, an aminosiloxane, a polymethylphenylsiloxane, a polyether polysiloxane copolymer; the vinyl content of the prepolymer containing vinyl side chains is 60 to 90 percent, preferably 70 to 85 percent; the weight average molecular weight of the prepolymer containing vinyl side chains is less than 8000 g/mol.

4. The silicone elastomer of claim 1, wherein the cross-linking agent is one of dicumyl peroxide, benzoyl peroxide, dicumyl hydroperoxide; the weight ratio of the cross-linking agent to the polysiloxane is in the range of 10% to 30%, preferably 15% to 25%.

5. Use of a silicone elastomer according to any one of claims 1-4 in a silicone OCA optical glue.

6. An organic silicon OCA optical cement is characterized in that,

the organic silicon OCA optical cement comprises a first release film, an organic silicon elastomer layer and a second release film which are sequentially stacked from bottom to top;

the raw material of the silicone elastomer layer is the silicone elastomer described in any one of claims 1 to 4;

preferably, the thickness of the silicone elastomer is 150-250 um; the thickness of the first release film is 30-80 um; the thickness of the second release film is 70-140 um; the release force of the first release film is 3-5 g; the second release film has a release force of 25-30 g.

7. A preparation method of the organic silicon OCA optical cement as claimed in claim 6, characterized by comprising the following steps:

step (1): uniformly mixing the raw materials of the silicone elastomer according to any one of claims 1 to 4 to obtain the silicone mixed solution, and removing bubbles in the silicone mixed solution at a pressure of 3 to 5Kg for 10 to 20 min;

step (2): spreading the first release film, coating the organic silicon mixed solution on the first release film according to a specified thickness by using a scraper or an optical coating machine, and curing the organic silicon elastomer at the temperature of 60-80 ℃ for 1-3 hours;

8. Use of the silicone elastomer of any one of claims 1-4 or the silicone OCA optical cement of claim 6 in an electronic display screen.

9. The bonding process of the silicone OCA optical cement as claimed in claim 6, wherein the bonding process comprises the following steps:

step (1): removing the release film on the binding surface of the organic silicon OCA optical cement, and placing the release film on a first loading platform of the binding jig;

step (2): treating the surface of the organic silicon elastomer layer of the organic silicon OCA optical cement by using a surface treating agent to enable the surface to have certain viscosity;

10. The process of claim 9, wherein the surface treatment agent in step (2) comprises 63.5-67.5 wt% of vinyltrimethoxysilane, 30-32.4 wt% of allyltrimethoxysilane and 0.1-2.5 wt% of a catalyst; preferably, the catalyst is selected from tetrabutyl titanate.