Modified silicone resin, its preparation method, silicone optical adhesive and its applications

Abstract

The present invention provides a modified silicone resin, which comprises a methyl MQ resin, an epoxy-modified MQ resin, a modifier, a basic catalyst, a first solvent and a second solvent; wherein, the M / Q ratio of the methyl MQ resin is 0.55 to 0.75, and the M / Q ratio of the epoxy-modified MQ resin is 0.7 to 0.9; the epoxy value of the epoxy-modified MQ resin is 0.06 to 0.16%; the modifier is a silicone compound containing a mercapto group and an alkoxy group. The silicone optical adhesive prepared from the modified silicone resin provided by the present invention has excellent optical properties, high and low temperature moduli, elongation at break and peel strength, and can achieve the characteristics of low initial peel force and high later peel force increase, which is convenient for timely repair in practical applications, so that it has excellent actual sticking effect and die-cutting effect, is convenient for coating in the process, and meets the requirements of mass production.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, and particularly relates to a modified silicone resin, a preparation method thereof, a silicone optical adhesive and an application thereof. Background Art

[0002] With the display function and operation convenience of touch display screens, their development speed and application scope have been rapidly improved in recent years; at the same time, higher requirements are also put forward for their quality. On the basis of meeting their functional applications, it is also necessary to improve their environmental adaptability and quality stability.

[0003] At present, most of the acrylic optical adhesives are used for the lamination of touch display screens in the market. They can be applied in conventional environments and have good adhesion effects. However, due to their relatively high glass transition temperature (Tg), they are prone to adhesive loss or shrinkage at low temperatures, resulting in abnormal display or touch of touch display screens at low temperatures; moreover, their high-temperature resistance performance is poor, and cohesive failure often occurs at high temperatures, resulting in displacement of the glass cover plate adhered to the display screen and causing abnormal touch; in addition, if the display screen is irradiated by ultraviolet rays outdoors for a long time, it is easy to appear oxidation and yellowing phenomena, affecting the display color and clarity of the display screen. In the prior art, silicone optical adhesives are also used for the lamination of display screens, but their stability is poor, and problems such as too high hardness and abnormal exhaustibility are easy to occur. Moreover, the initial lamination peel strength is basically the same as the peel strength after standing for 72 h. When rework is required due to poor initial lamination, it is not easy to operate due to the high peel strength; in addition, the refractive index of the current silicone optical adhesives is relatively low, and the display clarity needs to be improved.

[0004] In summary, based on the above technical problems, it is necessary to develop an optical adhesive for touch display screens with more excellent performance. Summary of the Invention

[0005] In view of the above, the present invention provides a modified silicone resin, a preparation method thereof, a silicone optical adhesive and an application thereof. The silicone optical adhesive prepared from the modified silicone resin provided by the present invention has excellent optical properties, high and low temperature moduli, a relatively high elongation at break and peel strength, has excellent actual lamination effect and die-cutting effect, and can achieve the characteristics of low initial peel force and high later creep, which is convenient for timely rework.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] The first aspect of the present invention provides a modified silicone resin, which comprises the following components: methyl MQ resin, epoxy-modified MQ resin, modifier, basic catalyst, first solvent and second solvent;

[0008] Among them, the M / Q ratio of the methyl MQ resin is 0.55 to 0.75, and the M / Q ratio of the epoxy-modified MQ resin is 0.7 to 0.9;

[0009] The epoxy value of the epoxy-modified MQ resin is 0.06 to 0.16%;

[0010] The modifier is an organosilicon compound containing a mercapto group and an alkoxy group.

[0011] The second aspect of the present invention provides a method for preparing the modified silicone resin described in the first aspect of the present invention. The method includes the following steps:

[0012] Mix the methyl MQ resin, the epoxy-modified MQ resin, the modifier, the basic catalyst, the first solvent, and the second solvent in the above-mentioned ratio and stir evenly; after introducing nitrogen, heat to 80 to 120 °C and maintain for 6 to 10 h until it reacts to a transparent liquid state; rotary evaporate the transparent liquid at 140 to 180 °C under a vacuum pressure of -0.1 MPa to -0.05 MPa for 2 to 6 h, and after cooling and increasing the pressure to normal temperature and pressure, the modified silicone resin is obtained.

[0013] The third aspect of the present invention provides a silicone optical adhesive. In terms of parts by weight, the silicone optical adhesive includes the following components:

[0014]

[0015] Among them, the modified silicone resin is the modified silicone resin described in the first aspect of the present invention or the modified silicone resin prepared by the method described in the second aspect of the present invention.

[0016] The fourth aspect of the present invention provides an application of the silicone optical adhesive. The silicone optical adhesive described in the third aspect of the present invention is applied to the lamination of a touch display screen.

[0017] Through the above technical solutions, the present invention has at least the following advantages compared with the prior art:

[0018] (1) For the modified silicone resin provided by the present invention, by using an organosilicon compound containing a mercapto group and an alkoxy group as a modifier, it can undergo co-blending grafting with the methyl MQ resin and the epoxy-modified MQ resin under the catalysis of a basic catalyst to achieve dehydroxylation in the composition. At the same time, due to the access of organic groups, the compatibility of the modified silicone resin with other silicone oils can be effectively improved, thereby improving the refractive index and light transmittance of the product to improve the clarity of the display;

[0019] (2) The epoxy groups contained in the modified silicone resin provided by the present invention and the alkoxy groups in the modifier can react with active groups such as hydroxyl groups on the surface of the adherend or form hydrogen bonds, enabling the initial peel force of the silicone optical adhesive to rise slowly only after 24 hours, thus achieving the characteristics of low initial peel force and high late-stage creep, which is convenient for timely repair.

[0020] The endpoints and any values in the ranges disclosed herein are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein. Detailed Description of the Invention

[0021] The following provides a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not used to limit the present invention.

[0022] The first aspect of the present invention provides a modified silicone resin, comprising the following components: methyl MQ resin, epoxy-modified MQ resin, modifier, basic catalyst, first solvent, and second solvent;

[0023] Among them, the M / Q ratio of the methyl MQ resin is 0.55 to 0.75, and the M / Q ratio of the epoxy-modified MQ resin is 0.7 to 0.9;

[0024] The epoxy value of the epoxy-modified MQ resin is 0.06 to 0.16%;

[0025] The modifier is an organosilicon compound containing a mercapto group and an alkoxy group.

[0026] Under the catalysis of an alkaline catalyst, the methyl MQ resin and epoxy-modified MQ resin in the modified silicone resin are blended and grafted with a modifier, an organosilicon compound containing a mercapto group and an alkoxy group, thereby achieving dehydroxylation within the composition. Since the hydroxyl group is a polar functional group, its presence can cause strong interactions between the silicone composition and components such as silicone oil in the adhesive component, reducing their compatibility. Through dehydroxylation, this interaction can be reduced, enabling the organic groups in the methyl MQ resin and epoxy-modified MQ resin to be smoothly incorporated into other components of the optical adhesive, thereby improving the compatibility between the modified silicone resin and components such as silicone oil in the silicone optical adhesive, and further enhancing the optical properties of the silicone optical adhesive, increasing the refractive index and light transmittance of the product, and improving the clarity of the display screen; in addition, the mercapto group and alkoxy group contained in the modifier can, under the action of the catalyst, cause partial alkoxy groups to undergo a grafting reaction with the silanol groups in the silicone resin to form a resin containing a mercapto group and an alkoxy group. During the addition reaction process of the optical adhesive, the mercapto group participates in part of the hydrosilylation reaction to form an S-Si bond. Since the new chemical bond has a higher polarity than the original siloxane bond and simultaneously increases the dielectric constant of the cured and crosslinked adhesive film, the refractive index of the silicone optical adhesive can be further increased.

[0027] Further, for the optical silicone composition according to the present invention, the M / Q ratio of the methyl MQ resin is 0.55 to 0.75. Exemplarily, the M / Q ratio of the methyl MQ resin can be 0.55, 0.6, 0.65, 0.7, 0.75, or any value between the two end values; the M / Q ratio of the epoxy-modified MQ resin is 0.7 to 0.9. Exemplarily, the M / Q ratio of the epoxy-modified MQ resin can be 0.7, 0.75, 0.8, 0.85, 0.9, or any value between the two end values. The M / Q ratio of the methyl MQ resin and the epoxy-modified MQ resin represents the number ratio of the monofunctional siloxane link (R3SiO 1 / 2 , i.e., M) to the tetrafunctional siloxane link (SiO 4 / 2 , i.e., Q) in the resin. By controlling the M / Q ratio of the methyl MQ resin and the epoxy-modified MQ resin, the relative amounts of the monofunctional siloxane link (R3SiO 1 / 2 , i.e., M) and the tetrafunctional siloxane link (SiO 4 / 2 , i.e., Q) can be adjusted, thereby avoiding an excessive or insufficient content of siloxane bonds. On the one hand, it can enable the modified silicone resin to form a more stable graft structure and enhance its thermal stability; on the other hand, it can avoid the deterioration of the polarity of the modified silicone resin caused by excessive siloxane bonds, thereby affecting the refractive index, light transmittance, and haze of the product.

[0028] In a specific embodiment, the weight-average molecular weight of the methyl MQ resin is 6,000 to 9,000 g / mol. Exemplarily, it can specifically be 6,000 g / mol, 6,500 g / mol, 7,000 g / mol, 7,500 g / mol, 8,000 g / mol, 8,500 g / mol, 9,000 g / mol, or any value between the two end values. By controlling the weight-average molecular weight of the methyl MQ resin within a suitable range, the modified silicone resin can obtain higher viscosity and mechanical strength, thereby improving the elongation at break of the optical adhesive and also improving the high and low temperature stability of the optical adhesive, enhancing its environmental adaptability.

[0029] In a specific embodiment, the hydroxyl content of the methyl MQ resin is 1.3 to 2.5%; Exemplarily, it can specifically be 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, or any value between the two end values.

[0030] Exemplarily, the mass range of the methyl MQ resin in the modified silicone resin is 30 to 60 parts by weight. Specifically, it can be 30 parts by weight, 31 parts by weight, 32 parts by weight, 33 parts by weight, 34 parts by weight, 35 parts by weight, 36 parts by weight, 37 parts by weight, 38 parts by weight, 39 parts by weight, 40 parts by weight, 42 parts by weight, 44 parts by weight, 46 parts by weight, 48 parts by weight, 50 parts by weight, 51 parts by weight, 53 parts by weight, 55 parts by weight, 57 parts by weight, 59 parts by weight, 60 parts by weight, or any value between the two end values.

[0031] Furthermore, the epoxy value of the epoxy-modified MQ resin is 0.06 to 0.16%. Exemplarily, the epoxy value of the epoxy-modified MQ resin can be 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, or any value between the two end values. The epoxy value represents the number of linked epoxy groups. Epoxy groups are a type of polar reactive and active group that can react with mercapto groups and hydroxyl groups, and can also form hydrogen bond interactions with hydrogen atoms containing activity. These interactions can further enhance the adhesion and mechanical strength of the adhesive, resulting in an increase in the peel strength.

[0032] In a specific embodiment, the weight-average molecular weight of the epoxy-modified MQ resin is 4,000 to 7,000 g / mol. Exemplarily, it can specifically be 4,000 g / mol, 4,500 g / mol, 5,000 g / mol, 5,500 g / mol, 6,000 g / mol, 6,500 g / mol, 7,000 g / mol, or any value between the two end values.

[0033] In a specific embodiment, the hydroxyl content of the epoxy-modified MQ resin is 0.3-1%. Exemplarily, the hydroxyl content of the epoxy-modified MQ resin can be 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, or any value between the two end values. The hydroxyl content directly affects the chemical reactivity of methyl MQ resin and epoxy-modified MQ resin. Resins with higher hydroxyl content are more likely to undergo chemical reactions with other compounds, including modifiers and catalysts added to the optical silicone composition. However, if the hydroxyl content of the resin is too high, the compatibility of the modified silicone resin will deteriorate; if the hydroxyl content is too low, the reaction degree of the resin will be insufficient.

[0034] In addition, in the present invention, the test method for the hydroxyl content in methyl MQ resin and epoxy-modified MQ resin adopts the reaction gas volume method. Lithium aluminum hydride is mainly used to react with the silanol groups in methyl MQ resin or epoxy-modified MQ resin to generate hydrogen gas. The generated hydrogen gas volume is collected and measured by a leveling flask, and the hydroxyl content is calculated based on the volume of hydrogen gas.

[0035] Exemplarily, the mass range of the epoxy-modified MQ resin in the modified silicone resin is 10-20 parts by weight, specifically it can be 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight, 20 parts by weight, or any value between the two end values.

[0036] Further, the modifier is an organosilicon compound containing a mercapto group and an alkoxy group, and the alkoxy group includes one or two of methoxy group and ethoxy group.

[0037] The epoxy groups contained in the modified silicone resin provided by the present invention and the alkoxy groups contained in the modifier can react with active groups such as hydroxyl groups on the surface of the adherend or form hydrogen bonds after a certain period of time. Therefore, it can be ensured that the peel strength of the silicone optical adhesive provided by the present invention only slowly increases after 24 hours, thus achieving the characteristics of low initial peel strength and high late-stage creep, which is convenient for timely repair.

[0038] In a specific embodiment, the content of the mercapto group in the modifier is 5.5-8.7%, and the content of the alkoxy group is 22.36-49.47%.

[0039] In a specific embodiment, the modifier includes at least one of 3-mercaptopropyltrimethoxysilane, 11-mercaptoundecyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and γ-mercaptopropyltriethoxysilane.

[0040] Exemplarily, the mass range of the modifier in the modified silicone resin is 8 to 18 parts by weight, specifically it can be 8 parts by weight, 9 parts by weight, 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, or any value between the two end values.

[0041] In a specific embodiment, the basic catalyst includes at least one of tetramethylammonium hydroxide pentahydrate and potassium hydroxide. They belong to strong bases and can catalyze silicone to break alkoxy groups and undergo condensation reactions with hydroxyl groups at low dosages. Tetramethylammonium hydroxide pentahydrate is preferably used for catalysis to facilitate subsequent decomposition and removal.

[0042] Exemplarily, the mass range of the basic catalyst in the modified silicone resin is 0.05 to 0.3 parts by weight, specifically it can be 0.05 parts by weight, 0.06 parts by weight, 0.07 parts by weight, 0.08 parts by weight, 0.09 parts by weight, 0.1 parts by weight, 0.12 parts by weight, 0.14 parts by weight, 0.16 parts by weight, 0.18 parts by weight, 0.2 parts by weight, 0.21 parts by weight, 0.23 parts by weight, 0.25 parts by weight, 0.27 parts by weight, 0.29 parts by weight, 0.3 parts by weight, or any value between the two end values.

[0043] In a specific embodiment, the first solvent includes at least one of absolute ethanol, methanol, and isopropyl alcohol. The first solvent is used to dissolve the above basic catalyst, enabling the basic catalyst to better mix with other components and promoting the progress of the reaction.

[0044] Exemplarily, the mass range of the first solvent in the modified silicone resin is 0.3 to 1 part by weight, specifically it can be 0.3 parts by weight, 0.4 parts by weight, 0.5 parts by weight, 0.6 parts by weight, 0.7 parts by weight, 0.8 parts by weight, 0.9 parts by weight, 1 part by weight, or any value between the two end values.

[0045] In a specific embodiment, the second solvent includes at least one of cyclohexane, heptane, and octane. The second solvent can provide a reaction medium for the above components to undergo a modification grafting reaction, making the mixture of each component uniform and ensuring the smooth progress of the reaction.

[0046] Exemplarily, the mass range of the second solvent in the modified silicone resin is 20 to 40 parts by weight, specifically it can be 20 parts by weight, 22 parts by weight, 24 parts by weight, 26 parts by weight, 28 parts by weight, 30 parts by weight, 31 parts by weight, 33 parts by weight, 35 parts by weight, 37 parts by weight, 39 parts by weight, 40 parts by weight, or any value between the two end values.

[0047] The modified silicone resin according to the present invention has the following component ratios in parts by weight:

[0048]

[0049] The second aspect of the present invention provides a method for preparing the modified silicone resin described in the first aspect of the present invention. The method includes the following steps:

[0050] Mix the methyl MQ resin, the epoxy-modified MQ resin, the modifier, the basic catalyst, the first solvent, and the second solvent evenly according to the above ratios; after introducing nitrogen, heat to 80-120°C and maintain for 6-10 h until it reacts to a transparent liquid state; subject the transparent liquid to rotary evaporation at 140-180°C and a vacuum pressure of -0.1 MPa to -0.05 MPa for 2-6 h, and then cool down and increase the pressure to normal temperature and pressure to obtain the modified silicone resin.

[0051] According to the method of the present invention, in the step, after introducing nitrogen into the material, heat to 80-120°C and maintain for 6-10 h until it reacts to a transparent liquid state; the heating temperature in the exemplary step can be 80°C, 90°C, 100°C, 110°C, 120°C, or any value between the two end values; the holding time can be 6 h, 7 h, 8 h, 9 h, 10 h, or any value between the two end values. This temperature range is mainly for the catalytic reaction process of tetramethylammonium hydroxide. This temperature and time are mainly for the condensation grafting reaction of mercapto groups, hydroxyl groups, and partial epoxy groups. If the temperature is too low, some reactions may not proceed, and if the time is too long, and if the temperature is too high, some catalysts may decompose and become ineffective, resulting in low reaction efficiency and low grafting rate.

[0052] According to the method of the present invention, in the step, subject the transparent liquid to rotary evaporation at 140-180°C for 2-6 h, and then cool down and increase the pressure to normal temperature and pressure to obtain the modified silicone resin. The rotary evaporation temperature in the exemplary step can be 140°C, 150°C, 160°C, 170°C, 180°C, or any value between the two end values; the rotary evaporation time can be 2 h, 3 h, 4 h, 5 h, 6 h, or any value between the two end values; the rotary evaporation pressure can be -0.1 MPa, -0.09 MPa, -0.08 MPa, -0.07 MPa, -0.06 MPa, -0.05 MPa, or any value between the two end values. This temperature and pressure are mainly for the thermal decomposition of the catalyst and vacuum pumping.

[0053] The third aspect of the present invention provides an organosilicon optical adhesive. The component ratios in the organosilicon optical adhesive are as follows in parts by weight:

[0054]

[0055] Among them, the modified silicone resin is the modified silicone resin described in the first aspect of the present invention or the modified silicone resin prepared by the method described in the second aspect of the present invention.

[0056] Due to the dehydroxylation treatment, the modified silicone resin provided by the present invention can generate a silicone resin containing mercapto and alkoxy groups after the reaction. This resin can react with the hydrogen-containing silicone oil with both ends and two different molecular weight vinyl silicone oils in the optical adhesive under the conditions of platinum catalyst and heating to obtain an adhesive with a ring-shaped interlocked polysiloxane skeleton with a macromolecular chain, realizing the stable control of its modulus, elongation at break, and fracture strength, so that the silicone optical adhesive prepared by the present invention has excellent high and low temperature moduli, a relatively high elongation at break, and the characteristics of low initial peel strength and high subsequent creep.

[0057] In the present invention, the viscosity of the vinyl silicone oil A is 2,000 to 10,000 mPa·s. Exemplarily, specifically, it can be 2,000 mPa·s, 3,000 mPa·s, 4,000 mPa·s, 5,000 mPa·s, 6,000 mPa·s, 7,000 mPa·s, 8,000 mPa·s, 9,000 mPa·s, 10,000 mPa·s, or any value between the two end values.

[0058] In the present invention, the vinyl content of the vinyl silicone oil A is 0.12 to 0.23%. Exemplarily, specifically, it can be 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.2%, 0.21%, 0.22%, 0.23%, or any value between the two end values.

[0059] In the present invention, the content of the vinyl silicone oil A is 15 to 25 parts by weight. Exemplarily, it can be 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight, 20 parts by weight, 21 parts by weight, 22 parts by weight, 23 parts by weight, 24 parts by weight, 25 parts by weight, or any value between the two end values.

[0060] In the present invention, the viscosity of the vinyl silicone oil B is 50,000 to 100,000 mPa·s. Exemplarily, specifically, it can be 50,000 mPa·s, 55,000 mPa·s, 60,000 mPa·s, 65,000 mPa·s, 70,000 mPa·s, 75,000 mPa·s, 80,000 mPa·s, 85,000 mPa·s, 90,000 mPa·s, 95,000 mPa·s, 100,000 mPa·s, or any value between the two end values.

[0061] By using vinyl-terminated silicone oils with two different molecular weights and viscosities, the present invention can better control the high and low temperature moduli, fracture strength, and peel strength of the silicone optical adhesive.

[0062] For the silicone optical adhesive according to the present invention, the vinyl content in the vinyl-terminated silicone oil B is 0.03 - 0.07%, and exemplarily, it can specifically be 0.03%, 0.04%, 0.05%, 0.06%, or 0.07%, or any value between the two end values.

[0063] The vinyl content in the vinyl-terminated silicone oil A and the vinyl-terminated silicone oil B can directly affect their reaction activity. The vinyl groups at the ends can form more silicon-carbon bonds during the cross-linking process, providing a basic network structure. Excessive vinyl content will result in a relatively small molecular weight after cross-linking and affect the final tensile and compressive properties of the product, manifested as a decrease in the fitting bubbles and the climbing amplitude of the peel force when using the adhesive film. However, too little vinyl content will lead to an overly slow cross-linking reaction or even an insufficient reaction, resulting in low cohesive strength and delamination of the adhesive film. Therefore, by adjusting the vinyl content of the two vinyl-terminated silicone oils, the present invention can effectively balance the cross-linking structure stability and the compatibility between components, and can generate a polysiloxane backbone with a cyclic structure, thereby further enhancing the cross-linking stability of the optical adhesive.

[0064] In the present invention, the content of the vinyl-terminated silicone oil B is 30 - 40 parts by weight, and exemplarily, it can be 30 parts by weight, 31 parts by weight, 32 parts by weight, 33 parts by weight, 34 parts by weight, 35 parts by weight, 36 parts by weight, 37 parts by weight, 38 parts by weight, 39 parts by weight, 40 parts by weight, or any value between the two end values.

[0065] In the present invention, the content of the modified silicone resin is 15 - 25 parts by weight, and exemplarily, it can be 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight, 20 parts by weight, 21 parts by weight, 22 parts by weight, 23 parts by weight, 24 parts by weight, 25 parts by weight, or any value between the two end values.

[0066] In the present invention, the inhibitor includes at least one of vinyl cyclics, alkynols, and diallyl maleate. Alkynols are preferred, mainly due to their excellent inhibition stability at room temperature, fast inactivation speed at high temperature, and fast product reaction.

[0067] In the present invention, the content of the inhibitor is 0.02 - 0.08 parts by weight, and exemplarily, it can be 0.02 parts by weight, 0.03 parts by weight, 0.04 parts by weight, 0.05 parts by weight, 0.06 parts by weight, 0.07 parts by weight, 0.08 parts by weight, or any value between the two end values.

[0068] In the present invention, the hydrogen content of the hydrogen-terminated silicone oil is 0.04 to 0.08%, and exemplarily, it can specifically be 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, or any value between the two end values.

[0069] In the present invention, the viscosity of the hydrogen-terminated silicone oil is 300 to 700 mm 2 / s, and exemplarily, it can specifically be 300 mm 2 / s, 350 mm 2 / s, 400 mm 2 / s, 450 mm 2 / s, 500 mm 2 / s, 550 mm 2 / s, 600 mm 2 / s, 650 mm 2 / s, 700 mm 2 / s; or any value between the two end values.

[0070] In the present invention, the content of the hydrogen-terminated silicone oil is 3 to 8 parts by weight, and exemplarily, it can be 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, or any value between the two end values.

[0071] In the present invention, the hydrogen content of the hydrogen-containing silicone resin is 0.2 to 0.5%; exemplarily, the hydrogen content of the hydrogen-containing silicone resin can be 0.2%, 0.3%, 0.4%, 0.5%, or any value between the two end values.

[0072] In the present invention, the M / Q ratio of the hydrogen-containing silicone resin is 1.2 to 1.5, and exemplarily, the M / Q ratio of the hydrogen-containing silicone resin can be 1.2, 1.3, 1.4, 1.5, or any value between the two end values.

[0073] In the present invention, the viscosity of the hydrogen-containing silicone resin is 500 to 1,500 mPa·s, and exemplarily, it can specifically be 500 mPa·s, 550 mPa·s, 600 mPa·s, 650 mPa·s, 700 mPa·s, 745 mPa·s, 850 mPa·s, 960 mPa·s, 1,070 mPa·s, 1,080 mPa·s, 1,090 mPa·s, 1,100 mPa·s, 1,150 mPa·s, 1,200 mPa·s, 1,250 mPa·s, 1,300 mPa·s, 1,350 mPa·s, 1,400 mPa·s, 1,450 mPa·s, 1,500 mPa·s, or any value between the two end values.

[0074] In the present invention, the content of the hydrogen-containing silicone resin is 0.1 to 0.4 parts by weight. Exemplarily, it can be 0.1 part by weight, 0.2 parts by weight, 0.3 parts by weight, 0.4 parts by weight, or any value between the two end values.

[0075] In the present invention, the Pt content of the platinum catalyst is 0.4 to 0.5%. Exemplarily, specifically it can be 0.4%, 0.45%, 0.5%, or any value between the two end values.

[0076] In the present invention, the content of the platinum catalyst is 0.015 to 0.05 parts by weight. Exemplarily, it can be 0.015 parts by weight, 0.02 parts by weight, 0.025 parts by weight, 0.03 parts by weight, 0.035 parts by weight, 0.04 parts by weight, 0.045 parts by weight, 0.05 parts by weight, or any value between the two end values. The addition of conventional platinum catalysts is prone to the phenomenon of yellowing of the glue film under high-temperature curing and baking; the platinum catalyst used in the present invention is of the model CSAT-F50050V produced by Jiangxi BETLEY New Materials Co., Ltd., which has no obvious yellowing phenomenon under high-temperature baking, can improve the display color and clarity of the screen during long-term use, and improve the visual experience.

[0077] A diluent can also be added to the silicone optical adhesive of the present invention to adjust the coating viscosity. The dosage of the diluent can be determined according to the required solid content. In the present invention, the dosage of the diluent can be 40 to 60 parts by weight, such as 40 parts by weight, 41 parts by weight, 42 parts by weight, 45 parts by weight, 47 parts by weight, 48 parts by weight, 50 parts by weight, 52 parts by weight, 54 parts by weight, 55 parts by weight, 57 parts by weight, 60 parts by weight, or any value between the two end values. For the specific selection of the diluent, conventional diluents can be selected. In the present invention, at least one of cyclohexane and heptane can be selected.

[0078] The present invention also provides a preparation method of the silicone optical adhesive, which is specifically as follows: Add each component into a reaction kettle according to the above ratio and stir well. During the stirring process, the temperature does not exceed 35°C. After stirring for 1 to 3 hours, the above-mentioned silicone optical adhesive can be obtained.

[0079] The fourth aspect of the present invention provides an application of the silicone optical adhesive, applying the silicone optical adhesive described in the third aspect of the present invention to the lamination of a touch display screen.

[0080] The silicone optical adhesive of the present invention can be made into a glue film form for practical applications. The glue film structure includes a first release film layer, a silicone optical adhesive layer, and a second release film layer laminated in sequence; wherein, the silicone optical adhesive layer contains the silicone optical adhesive described in the third aspect of the present invention.

[0081] When the silicone optical adhesive of the present invention is used for coating, the coating liquid needs to be formulated 60 minutes before coating. First, the components of the silicone optical adhesive are mixed evenly, and the corresponding weight parts of diluent (such as cyclohexane) are added according to the coating viscosity and solid content requirements, and dispersed for about 30 minutes at a stirring speed of 200 - 300 r / min. Then, vacuum defoaming treatment is carried out until there are no bubbles in the coating liquid under the observation of a strong light lamp, and then coating can be started on the release substrate. During the coating process, comma knife coating, Lip die (lip film extrusion type) or Slot die (slit die extrusion type) can be used for coating. The thickness of the coated adhesive film can be controlled according to actual needs, for example, controlled within 50 - 1,000 μm. After coating, the adhesive film can be shaped by an oven (the maximum temperature is set at 150 °C and the machine speed is 2 - 10 m / min) to obtain the silicone optical adhesive film.

[0082] The silicone optical adhesive film obtained by the present invention has excellent optical properties and excellent modulus control, can improve the bonding clarity of the touch display screen, and at the same time achieve the effects of low initial bonding peel force and obvious increase in peel force after standing for a period of time, which is convenient for timely repair of the adhesive film, and solves the problem of low adhesion force during the use after bonding of the adhesive film product, resulting in delamination and movement between the adhered objects.

[0083] The following will further elaborate on the present invention in conjunction with specific embodiments. It should be understood that the following embodiments are only for illustrative explanation of the present invention and should not be construed as limiting the protection scope of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0084] Unless otherwise specified, the experimental methods used in the following embodiments are all conventional methods; the reagents, materials, etc. used in the following embodiments, unless otherwise specified, can all be obtained from commercial channels. 1 g in the following embodiments represents 1 weight part.

[0085] Preparation of modified silicone resin

[0086] Preparation Example 1

[0087] ① Composition of the modified silicone resin:

[0088] Methyl MQ resin (manufacturer: Chengdu Chenguang Boda New Materials Co., Ltd., model: MSR8803, weight average molecular weight is 7,210 g / mol, hydroxyl content is 1.61%, M / Q ratio is 0.65), 46 g;

[0089] Epoxy modified MQ resin (manufacturer: Hubei Longsheng Sihai New Materials Co., Ltd., model: SH - 023 - 4, epoxy value is 0.1%, weight average molecular weight is 5,200 g / mol, hydroxyl content is 1.0%, M / Q ratio is 0.8), 15 g;

[0090] Modifier: 3-mercaptopropyltrimethoxysilane (manufacturer: Zhuoli (Shanghai) Materials Co., Ltd., model: PR-903, mercapto group content 7.13%, methoxy group content 46.5%), 11.5 g;

[0091] Basic catalyst: Tetramethylammonium hydroxide pentahydrate (manufacturer: Aladdin Biochemical Technology Co., Ltd., purity 97%), 0.11 g;

[0092] First solvent: Absolute ethanol, 0.65 g;

[0093] Second solvent: Cyclohexane, 27 g.

[0094] ② Preparation method of modified silicone resin:

[0095] Mix the above components by weight and stir evenly, then stir with a three-dimensional mixer for 30 min at a speed of 1600 r / min; then pour the mixed solution into a 150 mL three-necked round-bottom flask, heat to about 100 °C under the protection of nitrogen (bubbling 240 per minute), and keep the reaction for about 8 h until clear and transparent; pour the obtained liquid into a rotary evaporator, heat to 160 °C, keep at a vacuum of -0.1 MPa for 4 h, and then cool and pressurize to normal temperature and pressure to obtain a transparent modified silicone resin.

[0096] Preparation Example 2

[0097] The preparation method of this preparation example is the same as that of Preparation Example 1, except that the types and amounts of the components are different, and the specific differences are as follows:

[0098] Methyl MQ resin (manufacturer: Chengdu Chenguang Boda New Materials Co., Ltd., model: MSR8808, weight-average molecular weight 6,000 g / mol, hydroxyl group content 1.3%, M / Q ratio 0.65), 30 g;

[0099] Epoxy-modified MQ resin: SH-023-4, 10 g;

[0100] Modifier: 3-mercaptopropyltrimethoxysilane, 8 g;

[0101] Basic catalyst: Tetramethylammonium hydroxide pentahydrate, 0.05 g;

[0102] First solvent: Absolute ethanol, 0.3 g;

[0103] Second solvent: Cyclohexane, 20 g.

[0104] Preparation Example 3

[0105] The preparation method of this preparation example is the same as that of Preparation Example 1, except that the types and dosages of the components are different, and the specific differences are as follows:

[0106] Methyl MQ resin (manufacturer: Chengdu Chenguang Boda New Materials Co., Ltd., model: MSR8803, weight-average molecular weight of 9,000 g / mol, hydroxyl content of 2.5%, M / Q ratio of 0.65), 60 g;

[0107] Epoxy-modified MQ resin: SH-023-4, 20 g;

[0108] Modifier: 3-mercaptopropyltrimethoxysilane, 18 g;

[0109] Alkaline catalyst: Tetramethylammonium hydroxide pentahydrate, 0.3 g;

[0110] First solvent: Absolute ethanol, 1 g;

[0111] Second solvent: Cyclohexane, 40 g.

[0112] Preparation Example 4 group

[0113] The preparation method of this preparation example group is the same as that of Preparation Example 1, mainly used to prepare the influence of epoxy-modified MQ resins with different epoxy values on the modified silicone resin. The difference is that the epoxy values of the epoxy-modified MQ resins are different, and the specific differences are as follows:

[0114] Preparation Example 4-1: Epoxy-modified MQ resin, manufacturer: Hubei Longsheng Sihai New Materials Co., Ltd., model: SH-023-7b, epoxy value of 0.06%, weight-average molecular weight of 5,400 g / mol, hydroxyl content of 0.5%, M / Q ratio of 0.8;

[0115] Preparation Example 4-2: Epoxy-modified MQ resin, manufacturer: Hubei Longsheng Sihai New Materials Co., Ltd., model: SH-023-4c, epoxy value of 0.16%, weight-average molecular weight of 5,300 g / mol, hydroxyl content of 0.6%, M / Q ratio of 0.7;

[0116] Preparation Example 4-3: Epoxy-modified MQ resin, manufacturer: Hubei Longsheng Sihai New Materials Co., Ltd., model: SH-023-7a, epoxy value of 0.04%, weight-average molecular weight of 5,250 g / mol, hydroxyl content of 0.65%, M / Q ratio of 0.75;

[0117] Preparation Example 4-4: Epoxy-modified MQ resin, manufacturer: Hubei Longsheng Sihai New Materials Co., Ltd., model: SH-023-4e, epoxy value of 0.18%, weight-average molecular weight of 5,600 g / mol, hydroxyl content of 4%, M / Q ratio of 0.8.

[0118] Preparation Example 5

[0119] The preparation method of this preparation example is the same as that of Preparation Example 1, and its components do not contain epoxy-modified MQ resin. The composition and dosage of the remaining components are the same as those of Preparation Example 1.

[0120] Preparation Example 6 Group

[0121] The preparation method of this preparation example group is the same as that of Preparation Example 1, which is mainly used to compare the influence of the modifier on the modified silicone resin. The difference lies in the dosage and structure of the modifier. The other components and their dosages are the same as those of Preparation Example 1. The specific differences are as follows:

[0122] Preparation Example 6-1: Without modifier;

[0123] Preparation Example 6-2: The modifier is an equal amount of methyltriethoxysilane containing only ethoxy groups (manufacturer: Aladdin Reagent Co., Ltd., product number (SKU): T103634-2.5L);

[0124] Preparation Example 6-3: The modifier is an equal amount of methyltrimethoxysilane containing only methoxy groups (manufacturer: Aladdin Reagent Co., Ltd., product number (SKU): T106658-2.5L).

[0125] Preparation of Silicone Optical Adhesive

[0126] Example 1

[0127] ① Composition of silicone optical adhesive:

[0128] Vinyl silicone oil A (manufacturer: Anbia Special Silicone (Nantong) Co., Ltd., model: Andisil VS 5000, viscosity 5,000 mPa·s, vinyl content 0.168%), 20 g;

[0129] Vinyl silicone oil B (manufacturer: Anbia Special Silicone (Nantong) Co., Ltd., model: Andisil VS80000, viscosity 80,000 mPa·s, vinyl content 0.0672%), 35 g;

[0130] Modified silicone resin prepared in Preparation Example 1, 17 g;

[0131] Inhibitor: 2-methyl-3-butyn-2-ol (manufacturer: Aladdin Biochemical Technology Co., Ltd., purity 98%), 0.06 g;

[0132] Bis-terminal hydrogen-containing silicone oil (manufacturer: Anbia Special Silicone (Nantong) Co., Ltd., model: Andisil CE-500, hydrogen content 0.07%, viscosity 500 mm 2 / s), 6 g;

[0133] Hydrogen-containing silicone resin (manufacturer: Shandong Dayi Chemical Co., Ltd., model: HMQ103 - 0.4%, hydrogen content 0.4%, M / Q ratio 1.3, viscosity 1,150 mPa·s), 0.3 g;

[0134] Platinum catalyst (manufacturer: Jiangxi Betterly New Materials Co., Ltd., model: CSAT - F50050V, Pt content 0.5%), 0.025 g;

[0135] Cyclohexane, 50 g.

[0136] ② Preparation method of silicone optical adhesive: Add each component into the reaction kettle according to the above ratio and stir well. Keep the stirring temperature above 35°C. After stirring for 2 h, silicone optical adhesive can be obtained, and it is reserved after vacuum defoaming.

[0137] Example 2

[0138] This example is carried out with reference to Example 1, and its preparation method is the same as that of Example 1. The difference lies in the different composition of the silicone optical adhesive, which is specifically as follows:

[0139] Vinyl silicone oil A (manufacturer: Ambia Specialty Silicones (Nantong) Co., Ltd., model: Andisil VS2000, viscosity 2,000 mPa·s, vinyl content 0.12%), 15 g;

[0140] Vinyl silicone oil B (manufacturer: Ambia Specialty Silicones (Nantong) Co., Ltd., model: Andisil VS50000, viscosity 50,000 mPa·s, vinyl content 0.0672%), 30 g;

[0141] Modified silicone resin prepared in Preparation Example 1, 15 g;

[0142] Inhibitor: 2 - methyl - 3 - butyn - 2 - ol, 0.02 g;

[0143] Bis - terminal hydrogen - containing silicone oil, 3 g;

[0144] Hydrogen - containing silicone resin (manufacturer: Shandong Dayi Chemical Co., Ltd., model: DY - HMQ211 - 0.2%, hydrogen content 0.2%, M / Q ratio 1.3, viscosity 650 mPa·s), 0.1 g;

[0145] Platinum catalyst, 0.015 g;

[0146] Cyclohexane, 40.27 g.

[0147] Example 3

[0148] This example is carried out with reference to Example 1, and its preparation method is the same as that of Example 1, except that the composition of the silicone optical adhesive is different. The specific differences are as follows:

[0149] Vinyl silicone oil A (manufacturer: Anbia Special Silicone (Nantong) Co., Ltd., model: Andisil VS10000, viscosity 10,000 mPa·s, vinyl content 0.23%), 25 g;

[0150] Vinyl silicone oil B (manufacturer: Anbia Special Silicone (Nantong) Co., Ltd., model: Andisil VS100000, viscosity 100,000 mPa·s, vinyl content 0.0672%), 40 g;

[0151] Modified silicone resin prepared in Preparation Example 1, 25 g;

[0152] Inhibitor: 2-methyl-3-butyn-2-ol, 0.08 g;

[0153] Double-ended hydrogen-containing silicone oil, 8 g;

[0154] Hydrogen-containing silicone resin (manufacturer: Shandong Dayi Chemical Co., Ltd., model: HMQ102-0.5%, hydrogen content 0.5%, M / Q ratio 1.2, viscosity 780 mPa·s), 0.4 g;

[0155] Platinum catalyst, 0.05 g;

[0156] Cyclohexane, 62.85 g.

[0157] Example 4

[0158] This example is carried out with reference to Example 1, and its preparation method is the same as that of Example 1, except that the modified silicone resin prepared in Preparation Example 2 in equal amount is used, and the compositions and dosages of other components are the same as those in Example 1.

[0159] Example 5

[0160] This example is carried out with reference to Example 1, and its preparation method is the same as that of Example 1, except that the modified silicone resin prepared in Preparation Example 3 in equal amount is used, and the compositions and dosages of other components are the same as those in Example 1.

[0161] Example 6 group

[0162] This example group is carried out with reference to Example 1, and its preparation method is the same as that of Example 1, except that the modified silicone resin prepared in Preparation Example 4 group in equal amount is used, and the compositions and dosages of other components are the same as those in Example 1. The specific differences are as follows:

[0163] Example 6-1: The modified silicone resin prepared in Preparation Example 4-1 was used;

[0164] Example 6-2: The modified silicone resin prepared in Preparation Example 4-2 was used;

[0165] Example 6-3: The modified silicone resin prepared in Preparation Example 4-3 was used;

[0166] Example 6-4: The modified silicone resin prepared in Preparation Example 4-4 was used.

[0167] Comparative Example 1

[0168] This comparative example was carried out with reference to Example 1, and its preparation method was the same as that of Example 1. The difference was that the modified silicone resin prepared in Preparation Example 5 with an equal amount was used.

[0169] Comparative Example 2 group

[0170] This comparative example group was carried out with reference to Example 1, and its preparation method was the same as that of Example 1. The difference was that the modified silicone resin prepared in Preparation Example 6 group with an equal amount was used, and the composition and dosage of other components were the same as those of Example 1. The specific differences are shown as follows:

[0171] Comparative Example 2-1: The modified silicone resin prepared in Preparation Example 6-1 was used;

[0172] Comparative Example 2-2: The modified silicone resin prepared in Preparation Example 6-2 was used.

[0173] Comparative Example 3

[0174] This comparative example was carried out with reference to Example 1. The only difference was that the modified silicone resin was not prepared according to the preparation method of Preparation Example 1, but was simply stirred and mixed, and stirred at 1600 r / min for 4 h by a three-dimensional mixer.

[0175] Comparative Example 4 group

[0176] This comparative example group was carried out with reference to Example 1. The only difference was that vinyl silicone oil A or vinyl silicone oil B was not added to the silicone optical adhesive, and in order to maintain the same solid content, the dosage of the diluent cyclohexane was adjusted. The specific differences are shown as follows:

[0177] Comparative Example 4-1: Vinyl silicone oil A was not added, and the dosage of cyclohexane was 37.24 g;

[0178] Comparative Example 4-2: Vinyl silicone oil B was not added, and the dosage of cyclohexane was 27.67 g.

[0179] Comparative Example 5 group

[0180] This comparative example group was carried out with reference to Example 1, except that the components in the silicone optical adhesive were different, and the specific differences are as follows:

[0181] Comparative Example 5-1: Without hydrogen-containing silicone oil at both ends, the dosage of cyclohexane was 46.17 g;

[0182] Comparative Example 5-2: Using an equal amount of conventional hydrogen-containing silicone oil (manufacturer: Dow Chemical, model: 7028, hydrogen content 1.4%, viscosity 22 mm 2 / s).

[0183] Comparative Example 6

[0184] This comparative example was carried out with reference to Example 1, except that a conventional silicone resin (manufacturer: Shandong Dayi Chemical Co., Ltd., model: DY-MQ102(0.8) methyl MQ silicone resin) was used instead of the modified silicone resin prepared in the present invention, and the other components and their preparation methods were the same as those in Example 1.

[0185] Test Example

[0186] The silicone optical adhesives prepared in the above examples and comparative examples were coated into adhesive films. The specific method: The coating liquid was coated on the release film by a comma knife. After coating, it was dried into an adhesive film through an oven (the maximum temperature was set at 150 °C and the machine speed was 8 m / min). The thickness of the dry adhesive film was 250 ± 10 μm, and a release film was laminated on the adhesive film surface to obtain the test samples. The test samples were tested using the following instruments and methods, and the test results were recorded in Table 1 and Table 2. Specifically:

[0187] (1) Optical property test

[0188] Using a spectrophotometer (CM-3600A), the transmittance (%) and haze (%) of the silicone optical adhesive film were tested by the full-band transmission method, and the refractive index (%) was tested using an Abbe refractometer.

[0189] Using HunterLab UltraScan VIS, the L, a, and b values were tested by the transmission method. The present invention mainly focuses on the change of the yellow value b, and the b value was recorded. In the optical adhesive, the transmittance is required to be > 90%, the haze ≤ 0.5%, and the b value ≤ 0.4.

[0190] (2) High and low temperature modulus test

[0191] Using a dynamic thermomechanical analyzer (DMA-TA), by the method of oscillatory shear, the storage modulus (KPa) of the silicone optical adhesive film at -30 °C, 23 °C, and 100 °C was tested respectively, and the modulus Tanδ at -30 °C, 23 °C, and 100 °C was tested respectively.

[0192] (3) Tensile Elongation at Break and Peel Strength Test

[0193] The tensile elongation at break (%) of the silicone optical adhesive film was tested according to GB / T 30776-2014 "Test Method for Tensile Strength and Tensile Elongation at Break of Adhesive Tape". Generally, it is more appropriate that the tensile elongation at break is between 1700 and 2500%.

[0194] The glue of each example and comparative example was coated on a 50-μm-thick PET substrate, and the others were the same as the preparation process of the test sample, obtaining a sample reinforced by PET for the following peel strength test. The bonding plate was glass. The peel strength (gf / in) at room temperature bonding for 30 minutes (RT / 30min) and at room temperature bonding for 72 hours (RT / 72h) was tested respectively by the 180° peel method. It is more appropriate that the peel strength at RT / 30min is between 300 and 550 gf / in, and the peel strength at RT / 72h needs to be > 800 gf / in.

[0195] (4) Test of Actual Bonding Effect and Die-Cutting Effect

[0196] Using a fully automatic bonding machine and the method of vacuum bonding and high-pressure defoaming, the bubble abnormality of 1000 pcs of optical silicone adhesive film under normal temperature vacuum bonding was tested, and the bubble abnormality rate (%) was recorded;

[0197] Using an aging ring tester and the method of simulating environmental aging at high temperature and high humidity, the bubble rebound of 1000 pcs of optical silicone adhesive film under D85 aging ring test for 960 h was tested, and the bubble rebound rate (%) was recorded;

[0198] Using a flat die-cutting machine and the method of continuous moving square die-cutting, the die-cutting glue overflow and die-cutting glue pulling abnormality of 1000 pcs of optical silicone adhesive film were tested, and the die-cutting abnormality rate (%) was recorded.

[0199] Table 1 Performance Test Results of Each Example

[0200]

[0201]

[0202] Table 2 Performance Test Results of Each Comparative Example

[0203]

[0204] From the test results in Table 1 and Table 2, it can be seen that the silicone optical adhesive prepared from the modified silicone resin provided by the present invention has good optical properties, a low b value, and good yellowing resistance; the storage modulus changes little at low, normal, and high temperatures, has a good elongation at break, and can achieve the characteristics of low initial peel force and high late-stage peel force, which is convenient for timely repair in practical applications and makes it have excellent actual sticking and die-cutting effects.

[0205] From the test results of 6 groups of examples, it can be seen that when epoxy-modified MQ resins with different epoxy values are used to prepare the modified silicone resin, when the epoxy value is relatively low, due to the low modulus, the probability of pulling the adhesive film during the die-cutting process reaches an unacceptable 0.5%, and at the same time, the peel force shows a decay phenomenon. When the epoxy value is relatively high, due to the high modulus, the probability of bonding bubbles during the film lamination reaches an unacceptable 0.5%.

[0206] From the test results of Comparative Example 1, it can be seen that when no epoxy-modified MQ resin is added, its elongation at break and peel strength will decrease significantly, and there are defects such as glue overflow and adhesive pulling during die-cutting. This is because after lamination, some epoxy groups are lacking to participate in forming chemical bonds with the surface active groups of the adherend, and at the same time, the internal active groups of the colloid are reduced, resulting in a decrease in the colloid strength and the phenomenon of adhesive pulling during die-cutting.

[0207] From the test results of Comparative Example 2 groups, it can be seen that when no modifier is added, or only a modifier composed of methoxy or ethoxy is added, the silicone optical adhesive prepared therefrom has abnormal optical properties due to low light transmittance and high haze and cannot be used normally. This is because the methyl MQ resin and the epoxy resin do not have a modifier to participate in the reaction to improve their compatibility with vinyl silicone oil, resulting in a decrease in compatibility and affecting the light transmittance.

[0208] From the test results of Comparative Example 3, it can be seen that when the modified silicone resin is prepared by a simple stirring method, its optical properties decline, and the b value is relatively high, indicating that it is not resistant to yellowing. The storage modulus increases at each temperature, the elongation at break decreases, and there are bubbles and rebound defects after lamination. This is because the grafting rate of the modifier and the resin hydroxyl groups decreases, resulting in a decrease in resin compatibility and abnormal optical properties; at the same time, the modifier participates in the reaction with the subsequently added vinyl silicone oil and hydrogen-containing silicone oil, resulting in an increase in the colloid modulus and abnormal bubbles during the lamination process.

[0209] From the test results of Comparative Example 4 groups, it can be seen that when only one kind of vinyl silicone oil is added to the silicone optical adhesive, its storage modulus increases, the elongation at break decreases, and there are bonding bubbles and rebound defects. This is because the single-component vinyl silicone oil undergoes an excessive ordered cross-linking reaction, resulting in the formation of a dense structure of the colloid and affecting the formation of the colloid entanglement structure.

[0210] From the test results of Comparative Example 5, it can be seen that when only conventional end-side hydrogen-containing silicone oil is used in the silicone optical adhesive, the elongation at break of the prepared silicone optical adhesive decreases significantly, and there are bubbles and poor rebound during lamination. This is because the end-side hydrogen-containing silicone oil mainly causes the colloid to form a dense elastomer after reaction, resulting in a significant decrease in the viscosity of the colloid. When the double-end hydrogen-containing silicone oil is not present, the storage modulus decreases, the elongation at break decreases, and there are abnormal bubbles.

[0211] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. An organosilicon optical adhesive, characterized in that, It includes the following components: vinyl silicone oil A, vinyl silicone oil B, modified silicone resin, and hydrogen-containing silicone oil with both ends; the viscosity of the vinyl silicone oil A is 2,000~10,000 mPa·s, and the viscosity of the vinyl silicone oil B is 50,000~100,000 mPa·s; Among them, the modified silicone resin includes the following components: methyl MQ resin, epoxy-modified MQ resin, modifier, basic catalyst, first solvent, and second solvent; by weight, the proportions of the components in the modified silicone resin are as follows: Methyl MQ resin 30~60 parts by weight Epoxy-modified MQ resin 10~20 parts by weight Modifier 8~18 parts by weight Basic catalyst 0.05~0.3 parts by weight First solvent 0.3~1 part by weight Second solvent 20~40 parts by weight The preparation method of the modified silicone resin includes the following steps: mixing the methyl MQ resin, the epoxy-modified MQ resin, the modifier, the basic catalyst, the first solvent, and the second solvent evenly according to the above proportions; after introducing nitrogen, heating to 80~120 °C and maintaining for 6~10 h until it reacts to a transparent liquid state; subjecting the transparent liquid to rotary evaporation at 140~180 °C under a vacuum pressure of -0.1 MPa~-0.05 MPa for 2~6 h, cooling and increasing the pressure to normal temperature and pressure to obtain the modified silicone resin; Among them, the M / Q ratio of the methyl MQ resin is 0.55~0.75, and the M / Q ratio of the epoxy-modified MQ resin is 0.7~0.9; The epoxy value of the epoxy-modified MQ resin is 0.06~0.16 %; The modifier is an organosilicon compound containing a mercapto group and an alkoxy group.

2. The silicone optical adhesive according to claim 1, wherein The weight-average molecular weight of the methyl MQ resin is 6,000~9,000 g / mol, and the hydroxyl content of the methyl MQ resin is 1.3~2.5 %; And / or, the weight-average molecular weight of the epoxy-modified MQ resin is 4,000~7,000 g / mol, and the hydroxyl content of the epoxy-modified MQ resin is 0.3~1 %.

3. The silicone optical adhesive according to claim 1, wherein The alkoxy group includes one or two of methoxy group and ethoxy group.

4. The silicone optical adhesive according to claim 1, characterized in that, The modifier includes at least one of 3-mercaptopropyltrimethoxysilane, 11-mercaptoundecyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and γ-mercaptopropyltriethoxysilane; And / or, the basic catalyst includes at least one of tetramethylammonium hydroxide pentahydrate and potassium hydroxide; And / or, the first solvent includes at least one of anhydrous ethanol, methanol, and isopropanol, and the second solvent includes at least one of cyclohexane, heptane, and octane.

5. The silicone optical adhesive according to claim 1, wherein By weight, the silicone optical adhesive includes the following components: Vinyl silicone oil A 15~25 parts by weight Vinyl silicone oil B 30~40 parts by weight Modified silicone resin 15~25 parts by weight Inhibitor 0.02~0.08 parts by weight Hydrogen-containing silicone oil with both ends 3~8 parts by weight Hydrogen-containing silicone resin 0.1~0.4 parts by weight Platinum catalyst 0.015~0.05 parts by weight.

6. The silicone optical adhesive according to claim 5, characterized in that, The vinyl content of the vinyl silicone oil A is 0.12 - 0.23%, and the vinyl content of the vinyl silicone oil B is 0.03 - 0.07%.

7. The silicone optical adhesive according to claim 5, wherein The hydrogen content of the hydrogen-containing silicone oil with two terminal groups is 0.04 - 0.08%, and the hydrogen content of the hydrogen-containing silicone resin is 0.2 - 0.5%; and / or, the M / Q ratio of the hydrogen-containing silicone resin is 1.2 - 1.5; and / or, the viscosity of the hydrogen-containing silicone oil at both ends is 300 to 700 mm 2 / s, and the viscosity of the hydrogen-containing silicone resin is 500 to 1,500 mPa·s; and / or, the inhibitor includes at least one of vinyl cyclics, alkynol, and diallyl maleate; and / or, the Pt content of the platinum catalyst is 0.4 - 0.5%.

8. The silicone optical adhesive according to any one of claims 1 - 7 is applied to the lamination of a touch display screen.

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