Silicone film and preparation method and application thereof

Abstract

The invention discloses a silicone film as well as a preparation method and application thereof, relates to the technical field of functional materials, and solves the problem that a high-molecular polymer film in the prior art cannot simultaneously have high transparency, impact resistance and mechanical properties. The silicone film with a'brick-mud 'structure is prepared through a grafting reaction of an epoxy siloxane polymer and IHP, hydroxyl-terminated vinyl polysiloxane serves as a matrix material to serve as a'mud' structure, a silicon-oxygen bond in the epoxy siloxane polymer reacts with a boron-oxygen group in the IHP to form a dynamic reversible chemical bond, and the film has the advantages that the film is uniform in thickness, good in mechanical property and good in mechanical property; and due to the rigid and flexible combined brick-mud structural design, the mechanical property and the impact resistance of the silicone film are remarkably improved. Meanwhile, due to the unique design of the chemical structure, molecular arrangement and microscopic physical characteristics of the silicone film, the silicone film shows excellent optical transparency. The method can be applied to preparation of coating films of folding mobile phones, displays and optical precision instruments.

Description

Technical Field

[0001] The present invention relates to the technical field of functional materials, and in particular to a silicone film and a preparation method and application thereof. Background Art

[0002] With the rapid development of modern industry and technology, polymer films have gradually become key application materials in various packaging industries, optical equipment, electronic display screens and other fields due to their unique properties and wide applicability. Among them, traditional polymer films (such as polyethylene, polypropylene, etc.) have the advantages of strong plasticity and high transparency, and have been widely used in packaging, daily consumer goods, medical care, electronics and other fields. However, during the application process, traditional polymer films are prone to breakage when bent or subjected to external forces, and are prone to warping, tearing and other phenomena, which limits their durability and service life, affecting their application under higher performance requirements.

[0003] In order to improve the above problems, researchers began to explore adding different types of reinforcing materials (such as graphene, nano-SiO2, carbon black and other nanomaterials) to traditional polymer films to improve their impact resistance and mechanical properties. However, when excessive reinforcing materials are used, they are unevenly distributed in the matrix material, resulting in an uneven film surface, which further affects the performance of the film and also affects the transparency of the film. Therefore, developing a polymer film that maintains high transparency while improving its impact resistance and mechanical properties has become a technical problem to be solved in this field. Summary of the invention

[0004] In order to solve the problem that existing high molecular polymer films cannot have both high transparency and impact resistance and mechanical properties, the present invention proposes a silicone film and a preparation method and application thereof. The technical solution of the present invention is as follows:

[0005] A silicone film is formed by grafting epoxysiloxane polymer with impact hardening material (IHP);

[0006] The impact hardening material comprises the following structural formula:

[0007]

[0008] The structural formula of the epoxysiloxane polymer is shown below:

[0009]

[0010] Furthermore, the IHP is prepared according to the preparation method disclosed in the Chinese document "The influence of the branched structure of the flexible main chain on the performance of IHP", which specifically involves the synthesis of IHP with linear hydroxyl-terminated polydimethylsiloxane as the flexible main chain in 1.2 experimental method of the Chinese document, and the specific preparation steps are: 2 s -1 Hydroxyl-terminated polydimethylsiloxane and trimethoxyboroxane are added to a nitrogen-filled sample bottle in a certain molar ratio, and the next step of reaction is continued at 120°C for 4 hours. When the reaction system is in a uniform state, isophorone diisocyanate is further added and reacted for 4 hours. Then, the reaction sample is placed in an oven at 120°C for drying to prepare IHP.

[0011] A method for preparing a silicone film comprises the following steps:

[0012] S1: adding 2-(3,4-epoxycyclohexane)ethyltrimethoxysilane, dimethyldiethylsilane and dibutyltin dilaurate into a beaker, heating and stirring to obtain an epoxysiloxane polymer; mixing the impact hardening material with the epoxysiloxane polymer at 120° C. to graft the boron oxygen dynamic bond in the impact hardening material with the ring-opened epoxy in the epoxysiloxane polymer to obtain a grafted epoxysiloxane polymer;

[0013] S2: adding the grafted epoxysiloxane polymer prepared in S1 to vinyl silicone oil and stirring to obtain a uniform mixture, and then adding methyl methacrylate, vinyl silicone oil, MQ resin, nano-SiO2 dissolved in silicone oil and a platinum-containing catalyst and stirring to react to obtain component A;

[0014] S3: mixing hydrogen-containing silicone oil and 1-alkynol inhibitor to obtain component B; adding component B to component A and mixing evenly to obtain a pre-solution; spreading the pre-solution into a polytetrafluoroethylene mold by a coating machine and drying to form a film to obtain a silicone film;

[0015] Further, the temperature of heating and stirring in S1 is 120°C;

[0016] Furthermore, the grafting in S1 is the grafting of epoxy bonds in the epoxysiloxane polymer and the boron-oxygen dynamic bonds in the IHP to form a branched network;

[0017] Furthermore, the stirring time in S2 is 30 min;

[0018] Further, the viscosity of the vinyl silicone oil monomer in S2 is 5000cst, 12000cst and 50000cst;

[0019] Further, the reaction temperature in S2 is 60° C. and the reaction time is 6 h;

[0020] Furthermore, the hydrogen-containing silicone oil in S3 is obtained by mixing high hydrogen-containing silicone oil and low hydrogen-containing silicone oil, the ratio of high hydrogen-containing silicone oil to low hydrogen-containing silicone oil is 4:6, wherein the hydrogen content of the high hydrogen-containing silicone oil is 1.6%, and the hydrogen content of the low hydrogen-containing silicone oil is 0.13%;

[0021] Furthermore, the mass ratio of component A to component B in S3 is 10:1;

[0022] Furthermore, in S3, the drying temperature is 100° C. and the drying time is 0.5 h.

[0023] An application of a silicone film is used in the preparation of coating films for folding mobile phones, displays, and optical precision instruments.

[0024] Compared with the prior art, the present invention solves the problem that the prior art polymer film cannot have both high transparency and impact resistance and mechanical properties. The specific beneficial effects are:

[0025] 1. Constructing a nacre-like "brick-mud" structure design: The present invention prepares a silicone film with a nacre-like "brick-mud" structure by grafting the epoxy groups on the epoxysiloxane polymer with the boron oxygen dynamic bond in IHP and adding them to the cross-linked network of terminal hydroxyl polysiloxane for reaction. The terminal hydroxyl vinyl polysiloxane acts as the "mud" structure. Since the siloxane chain segment has good elastic deformation ability, it can form a longer cross-linked network chain break and deformation dissipation impact energy through the slippage of the chain segment when stress is loaded; the dynamic reversible chemical bond formed by the reaction of the open-ring epoxy bond in the epoxysiloxane polymer and the boron oxygen group in IHP acts as the "brick" structure. This bond breaks and re-forms during the stress process, thereby further dissipating the impact energy and playing a role in strength support. This rigid-flexible "brick-mud" structure design significantly improves the mechanical properties and impact resistance of the silicone film.

[0026] 2. Excellent impact resistance: The silicone film prepared by the present invention uses a "brick-mud" structural design, so that when the film is subjected to a rapid impact, it can absorb a large amount of impact energy and quickly recover its deformation, showing excellent impact resistance; at the same time, the flexible siloxane main chain inside the film can extend and store energy during the stretching process, and then release the stress and quickly recover its deformation, showing excellent scalability and mechanical properties. The impact resistance of the silicone film prepared by the present invention can reach 82%, and the elongation at break can reach 1261%.

[0027] 3. High transparency: The silicone film prepared by the present invention has transparency, which is mainly due to the unique design of its chemical structure, molecular arrangement and microscopic physical properties. The silicon-oxygen bonds and methyl groups in the epoxysiloxane polymer do not absorb or scatter visible light, and the high degree of cross-linking and random arrangement in its molecular structure avoid light scattering. In addition, the "brick-mud" structure of the nacre further reduces the interference of light at the nanoscale, so that the film shows significant optical transparency while maintaining excellent mechanical properties. The transmittance of the silicone film is 94.6 and the haze is 0.62. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a photograph of the silicone film prepared in Example 4;

[0029] Figure 2 This is the infrared spectrum of the silicone film prepared in Example 4;

[0030] Figure 3 This is a diagram of the mechanical properties of the silicone film prepared in Example 4;

[0031] Figure 4 This is a diagram of the mechanical properties of the silicone film prepared in Comparative Example 1;

[0032] Figure 5 is a branched structure diagram of a grafted epoxysiloxane polymer;

[0033] Figure 6 This is an electron microscope image of the nacre brick-mud structure of the silicone film. DETAILED DESCRIPTION

[0034] In order to make the technical solution of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the specification of the present invention. It should be noted that the following embodiments are only used to better understand the technical solution of the present invention and should not be understood as a limitation to the present invention.

[0035] Example 1.

[0036] S1: 10 g of 2-(3,4-epoxycyclohexane)ethyltrimethoxysilane, 10 g of dimethyldiethylsilane and 1 g of dibutyltin dilaurate were added to a beaker, and stirred evenly at 120° C. to obtain an epoxysiloxane polymer; 4 g of IHP was added to a beaker at 120° C., and 10 g of the epoxysiloxane polymer was added to obtain a grafted epoxysiloxane polymer;

[0037] S2: 0.4 g of the grafted epoxysiloxane polymer prepared in S1 was added to 10 g of vinyl silicone oil with a viscosity of 500 cst and stirred for 30 min to obtain a uniform mixture, followed by the addition of 0.6 g of methyl methacrylate, a total of 22 g of terminal hydroxyl vinyl silicone oils with monomer viscosities of 5000 cst, 12000 cst and 50000 cst, 5 g of MQ resin, 2 g of nano-SIO2 dissolved in silicone oil and 0.1 g of a platinum-containing catalyst, and the mixture was stirred and reacted at 60 ° C for 6 h to obtain component A;

[0038] S3: Mix hydrogen-containing silicone oil and 0.01g of 1-alkynol inhibitor to obtain component B, wherein the hydrogen-containing silicone oil is a mixture of high hydrogen-containing silicone oil and low hydrogen-containing silicone oil, the ratio of high hydrogen-containing silicone oil to low hydrogen-containing silicone oil is 4:6, wherein the hydrogen content of the high hydrogen-containing silicone oil is 1.6%, and the hydrogen content of the low hydrogen-containing silicone oil is 0.13%; add component B to component A and mix evenly to obtain a pre-solution, wherein the mass ratio of component A to component B is 10:1; extend the pre-solution into a polytetrafluoroethylene mold using a coating machine, dry it at 100°C for 0.5h to form a film, and obtain a silicone film.

[0039] Example 2.

[0040] S1: The preparation method of the grafted epoxysiloxane polymer is the same as the preparation method and steps described in S1 in Example 1.

[0041] S2: 0.8 g of the grafted epoxysiloxane polymer prepared in S1 was added to 10 g of vinyl silicone oil with a viscosity of 500 cst and stirred for 30 min to obtain a uniform mixture, followed by the addition of 0.6 g of methyl methacrylate, a total of 21.6 g of hydroxy-terminated vinyl silicone oils with monomer viscosities of 5000 cst, 12000 cst and 50000 cst, 5 g of MQ resin, 2 g of nano-SIO2 dissolved in silicone oil and 0.1 g of a platinum-containing catalyst, and the mixture was stirred and reacted at 60° C. for 6 h to obtain component A;

[0042] S3: Mix hydrogen-containing silicone oil and 0.01g of 1-alkynol inhibitor to obtain component B, wherein the hydrogen-containing silicone oil is a mixture of high hydrogen-containing silicone oil and low hydrogen-containing silicone oil, the ratio of high hydrogen-containing silicone oil to low hydrogen-containing silicone oil is 4:6, wherein the hydrogen content of the high hydrogen-containing silicone oil is 1.6%, and the hydrogen content of the low hydrogen-containing silicone oil is 0.13%; add component B to component A and mix evenly to obtain a pre-solution, wherein the mass ratio of component A to component B is 10:1; extend the pre-solution into a polytetrafluoroethylene mold using a coating machine, dry it at 100°C for 0.5h to form a film, and obtain a silicone film.

[0043] Example 3.

[0044] S1: The preparation method of the grafted epoxysiloxane polymer is the same as the preparation method and steps described in S1 in Example 1.

[0045] S2: 1.2 g of the grafted epoxysiloxane polymer prepared in S1 was added to 10 g of vinyl silicone oil with a viscosity of 500 cst and stirred for 30 min to obtain a uniform mixture, followed by the addition of 0.6 g of methyl methacrylate, a total of 21.2 g of hydroxy-terminated vinyl silicone oils with monomer viscosities of 5000 cst, 12000 cst and 50000 cst, 5 g of MQ resin, 2 g of nano-SIO2 dissolved in silicone oil and 0.1 g of a platinum-containing catalyst, and the mixture was stirred and reacted at 60 ° C for 6 h to obtain component A;

[0046] S3: Mix hydrogen-containing silicone oil and 0.01g of 1-alkynol inhibitor to obtain component B, wherein the hydrogen-containing silicone oil is a mixture of high hydrogen-containing silicone oil and low hydrogen-containing silicone oil, the ratio of high hydrogen-containing silicone oil to low hydrogen-containing silicone oil is 4:6, wherein the hydrogen content of the high hydrogen-containing silicone oil is 1.6%, and the hydrogen content of the low hydrogen-containing silicone oil is 0.13%; add component B to component A and mix evenly to obtain a pre-solution, wherein the mass ratio of component A to component B is 10:1; extend the pre-solution into a polytetrafluoroethylene mold using a coating machine, dry it at 100°C for 0.5h to form a film, and obtain a silicone film.

[0047] Example 4.

[0048] S1: The preparation method of the grafted epoxysiloxane polymer is the same as the preparation method and steps described in S1 in Example 1.

[0049] S2: 1.6 g of the grafted epoxysiloxane polymer prepared in S1 was added to 10 g of vinyl silicone oil with a viscosity of 500 cst and stirred for 30 min to obtain a uniform mixture, followed by the addition of 0.6 g of methyl methacrylate, a total of 20.8 g of terminal hydroxyl vinyl silicone oils with monomer viscosities of 5000 cst, 12000 cst and 50000 cst, 10 g of MQ resin, 2 g of nano-SIO2 dissolved in silicone oil and 0.1 g of platinum-containing catalyst, and the mixture was stirred and reacted at 60° C. for 6 h to obtain component A;

[0050] S3: Mix hydrogenated silicone oil and 0.01g 1-alkynol inhibitor to obtain component B, wherein the hydrogenated silicone oil is a mixture of high hydrogenated silicone oil and low hydrogenated silicone oil, the ratio of high hydrogenated silicone oil to low hydrogenated silicone oil is 4:6, wherein the hydrogen content of high hydrogenated silicone oil is 1.6%, and the hydrogen content of low hydrogenated silicone oil is 0.13%; add component B to component A and mix evenly to obtain a pre-solution, wherein the mass ratio of component A to component B is 10:1; extend the pre-solution into a polytetrafluoroethylene mold by a coating machine, dry it at 100°C for 0.5h to form a film, and obtain a silicone film. Figure 1This is a photo of the silicone film prepared in Example 4. It can be seen that the silicone film is fully transparent, with a transmittance of 94.6 and a haze of 0.62. Figure 2 This is the infrared spectrum of the silicone film prepared in Example 4. -1 、950cm -1 、791cm -1 The three peaks at 950cm- -1 The absorption peak of Si-OH is shown at 3389 cm-1, but it is weaker than the absorption peak of the corresponding monomer, confirming the existence of silane polymerization in the film. -1 The -CH2- symmetric stretching vibration at 2930cm -1 To 2868cm -1 The asymmetric stretching vibration of -CH2- is present at 1255cm -1 The symmetrical stretching vibration of COC is shown at 791 cm -1 The absorption band weakened, proving that the epoxy groups in the film decreased and some epoxy groups were not ring-opened.

[0051] Comparative Example 1.

[0052] S1: Add 0.6 g of methyl methacrylate, 21.6 g of terminal hydroxyl vinyl silicone oils with monomer viscosities of 5000 cst, 12000 cst, and 50000 cst, 5 g of MQ resin, 2 g of nano-SIO2 dissolved in silicone oil, and 0.1 g of platinum-containing catalyst to 10 g of vinyl silicone oil with a viscosity of 500 cst, and stir the mixture at 60° C. for 6 h to obtain component A;

[0053] S2: Mix hydrogen-containing silicone oil and 0.01g of 1-alkynol inhibitor to obtain component B, wherein the hydrogen-containing silicone oil is a mixture of high hydrogen-containing silicone oil and low hydrogen-containing silicone oil, the ratio of high hydrogen-containing silicone oil to low hydrogen-containing silicone oil is 4:6, wherein the hydrogen content of the high hydrogen-containing silicone oil is 1.6%, and the hydrogen content of the low hydrogen-containing silicone oil is 0.13%; add component B to component A and mix evenly to obtain a pre-solution, wherein the mass ratio of component A to component B is 10:1; extend the pre-solution into a polytetrafluoroethylene mold using a coating machine, dry it at 100°C for 0.5h to form a film, and obtain a silicone film.

[0054] Impact resistance test:

[0055] The silicone film samples prepared in the above Examples 1-4 and Comparative Example 1 were cut into the same size and fixed on a testing device. A 5 kg drop weight was released from a height of 80 cm to perform free impact and hit the center of the sample.

[0056] Mechanical properties test:

[0057] The silicone film samples prepared in the above Examples 1-4 and Comparative Example 1 were cut into the same size (the size was prepared according to the Chinese national standard GB / T 1040.2-2022), and then the tensile properties were tested. The following table shows the impact resistance and elongation at break results of the silicone film samples prepared in Examples 1-4 and Comparative Example 1:

[0058]

[0059]

[0060] According to the data in the table, the impact resistance and elongation at break of the silicone films prepared in Examples 1-4 show an upward trend as the content of the grafted epoxysiloxane polymer increases. The impact resistance of the silicone film prepared in Example 4 can reach 82.35%, which is much higher than that of the silicone film prepared in Comparative Example 1; the elongation at break of the silicone film prepared in Example 4 can reach 1267% ( Figure 3 ), which is much higher than the elongation at break of the silicone film prepared in Comparative Example 1 ( Figure 4 This is mainly due to the grafting of the epoxy bonds in the siloxane polymer with the boron-oxygen dynamic bonds in the IHP to form a branched network ( Figure 5 ), and then form a silicone film like the "brick-mud" structure of nacre, Figure 6 This is an electron microscope image of the pearl layer "brick-mud" structure of the silicone film. The terminal hydroxyl vinyl polysiloxane acts as the matrix material to act as the "mud" structure. Since the siloxane chain segment has good elastic deformation ability, it can dissipate the impact energy through the slip and deformation of the chain segment when stress is loaded; the silicon oxygen bond in the epoxysiloxane polymer and the boroxy group in the IHP will form a dynamic reversible chemical bond, acting as the "brick" structure. This bond breaks and re-forms during the stress process, thereby further dissipating the impact energy and playing a role in strength support. This rigid-flexible "brick-mud" structural design significantly improves the mechanical properties and impact resistance of the silicone film.

[0061] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0062] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest range consistent with the principles and novel features disclosed herein.

Claims

1. A silicone film, characterized in that: It is formed by the graft reaction of epoxysiloxane polymer and impact hardening material; The impact hardening material comprises the following structural formula:

2. The silicone film according to claim 1, characterized in that The epoxysiloxane polymer structural formula is shown below:

3. A method for preparing a silicone film as claimed in claim 1 or 2, characterized in that: The following steps are involved: S1: adding 2-(3,4-epoxycyclohexane)ethyltrimethoxysilane, dimethyldiethylsilane and dibutyltin dilaurate into a beaker, heating and stirring to obtain an epoxysiloxane polymer; mixing the impact hardening material with the epoxysiloxane polymer at 120° C. to graft the boron oxygen dynamic bond in the impact hardening material with the ring-opened epoxy in the epoxysiloxane polymer to obtain a grafted epoxysiloxane polymer; S2: adding the grafted epoxysiloxane polymer prepared in S1 to vinyl silicone oil and stirring to obtain a uniform mixture, and then adding methyl methacrylate, vinyl silicone oil, MQ resin, nano-SiO2 dissolved in silicone oil and a platinum-containing catalyst and stirring to react to obtain component A; S3: Mix hydrogen-containing silicone oil and 1-alkynol inhibitor to obtain component B; add component B to component A and mix evenly to obtain a pre-solution; spread the pre-solution into a polytetrafluoroethylene mold by a coating machine and dry it to form a film to obtain a silicone film.

4. The method for preparing a silicone film according to claim 3, characterized in that: The temperature of heating and stirring in S1 is 120°C.

5. The method for preparing a silicone film according to claim 3, characterized in that: The stirring time in S2 is 30 minutes; the viscosity of the vinyl silicone oil monomer in S2 is 5000 cst, 12000 cst and 50000 cst.

6. The method for preparing a silicone film according to claim 3, characterized in that: The reaction temperature in S2 is 60° C. and the reaction time is 6 h.

7. The method for preparing a silicone film according to claim 3, characterized in that: The hydrogen-containing silicone oil in S3 is a mixture of high hydrogen-containing silicone oil and low hydrogen-containing silicone oil, the mass ratio of high hydrogen-containing silicone oil to low hydrogen-containing silicone oil is 4:6, wherein the hydrogen content of the high hydrogen-containing silicone oil is 1.6%, and the hydrogen content of the low hydrogen-containing silicone oil is 0.13%.

8. The method for preparing a silicone film according to claim 3, characterized in that: The mass ratio of component A to component B in S3 is 10:

1.

9. The method for preparing a silicone film according to claim 3, characterized in that: The drying temperature in S3 is 100° C. and the drying time is 0.5 h.

10. Use of the silicone film according to claim 1 or 2 or the silicone film prepared by the preparation method according to any one of claims 3 to 9, characterized in that: Used in the preparation of coating films for foldable mobile phones, displays, and optical precision instruments.

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