High-cohesiveness organic silicon pouring sealant for LED display screen and preparation method of high-cohesiveness organic silicon pouring sealant

Abstract

The invention relates to the technical field of organic silicon pouring sealants, in particular to a high-cohesiveness organic silicon pouring sealant for an LED display screen and a preparation method thereof.The high-cohesiveness organic silicon pouring sealant for the LED display screen comprises a component A and a component B. The component A is composed of, by weight, 100 parts of hydroxyl-terminated vinyl silicone oil; 1-3 parts of a silane coupling agent; 0.1 to 2 parts of a catalyst I; 80-200 parts of a heat-conducting filler; 10 to 30 parts of a flame retardant; and 20-30 parts of organic silicon resin. The component B is composed of the following components in parts by weight: 2-15 parts of hydrogen-containing silicone oil; 1-3 parts of an adhesion promoter; 0.1 to 0.4 part of an inhibitor; 0.1 to 0.5 part of a catalyst II; 1-5 parts of an anti-settling agent; 200 to 500 parts of a reinforcing filler; and 8-12 parts of a diluent. The silicon pouring sealant prepared by the invention has the advantages of high cohesiveness, flame retardance, settling resistance, higher heat conductivity coefficient, high and low temperature resistance and excellent mechanical properties.

Description

Technical Field

[0001] The present application belongs to the technical field of organic silicon potting adhesives, and in particular, relates to an organic silicon potting adhesive with high adhesion for LED display screens and a preparation method thereof. Background Art

[0002] As electronic components, power circuit modules, large integrated circuit boards, LEDs and other high-tech fields further achieve high performance, high reliability and miniaturization, modern electronic technology develops with each passing day. LED displays have been widely used in various fields of social life, and the requirements for LED displays are getting higher and higher. Especially in the relatively complex outdoor working environment, high requirements for weather resistance, waterproofness and moisture resistance are required, and high-quality potting protection is required for outdoor LED devices.

[0003] Potting is the process of arranging, assembling, connecting, isolating and protecting the electronic components according to the requirements. Potting glue is a polymer composite material used for bonding, sealing and coating protection of electronic components. It can effectively prevent the erosion of electronic components by water, dust and harmful gases, improve the stability of internal components, and is widely used in aerospace, automobile, chip, LED packaging materials and other fields with high requirements for thermal conductivity. At present, the most commonly used potting materials are various synthetic polymers, among which epoxy resin, polyurethane and silicone rubber are widely used. Epoxy resin material has low cost, but its high temperature resistance and moisture resistance are poor, which can easily damage components, shorten the service life of components, and even cause problems such as short circuit. The hardness of polyurethane potting glue cannot be very low, and the product can only be applied to drip glue type or semi-tube type soft light strips. As the temperature decreases, the flexibility of the light strip changes greatly.

[0004] Silicone potting compound is a commonly used potting material for electronic devices. It refers to a type of electronic potting compound made of silicone rubber, including single-component silicone potting compound and two-component silicone potting compound. Silicone potting compound has excellent insulation properties, high temperature resistance, aging resistance, and good chemical stability. It is currently favored in the fields of LED packaging, motor potting and sealing protection, and has become one of the ideal electronic potting materials. Although silicone potting compound has advantages that other potting compounds cannot match, organic potting compounds also have the disadvantage of poor bonding properties, which limits their scope of use to a certain extent. Therefore, seeking a high-bonding silicone potting compound for LED display screens to meet the needs of adapting to different environments is a technical problem that needs to be urgently solved by technicians in this field. Summary of the invention

[0005] The present invention provides a high-adhesive silicone potting adhesive for an LED display screen and a preparation method thereof. The silicone potting adhesive has excellent bonding performance, good fluidity, is not easy to settle, has a high thermal conductivity, and can effectively improve tensile strength and shear strength. It has excellent mechanical properties, is more reliable and stable in responding to mechanical requirements in various environments, can meet the requirements of long-term use in high and low temperature environments, and has broad market prospects.

[0006] In order to solve the above technical problems, one of the purposes of the present invention is to provide a high-adhesive silicone potting adhesive for LED display screens, comprising component A and component B, wherein component A comprises the following components in parts by weight: 100 parts of hydroxy-terminated vinyl silicone oil; 1-3 parts of silane coupling agent; Catalyst I 0.1-2 parts; Thermal conductive filler 80-200 parts; Flame retardant 10-30 parts; 20-30 parts of silicone resin.

[0007] The B component includes the following components in parts by weight: 2-15 parts of hydrogen silicone oil; 1-3 parts of adhesion promoter; Inhibitor 0.1-0.4 parts; Catalyst II 0.1-0.5 parts; 1-5 parts of anti-settling agent; Reinforcing filler 200-500 parts; 8-12 parts of diluent.

[0008] The terminal hydroxyl vinyl silicone oil is an important organic silicon material with heat resistance, weather resistance, electrical insulation performance, physiological inertness, low surface tension and low surface energy. It is widely used in silicone rubber, coatings, textiles, electronics, chemical light industry, metals and paints and other fields. The vinyl content is 0.1-0.5% and the viscosity is 500cp-2000cp.

[0009] The hydrogen-containing silicone oil is a polysiloxane with a hydrogen content of 0.15-0.5% and a viscosity of 40-200cp. Under the action of a metal catalyst, it can be cross-linked at an appropriate temperature to form a waterproof film on the surface of various substrates. It is widely used as a waterproofing agent, anti-adhesive agent or anti-corrosion agent for fabrics, fire extinguishing agents (dry powder), paper, metal, leather, wood, glass, cement, ceramics, marble, etc. It has particularly excellent hydrophobicity and can be waterproof, dustproof and corrosion-resistant. It is often used as a cross-linking agent for addition-type liquid silicone rubber, which can improve the performance of silicone, optimize its physical properties, improve its high and low temperature resistance, and enhance the stability of silicone.

[0010] The silicone resin is an MQ silicone resin containing vinyl functional groups, with a mass fraction of vinyl of 3%. It is a highly cross-linked polysiloxane with a network structure, and contains both "organic groups" and "inorganic structures" in its structure. This special composition and molecular structure enables it to combine the properties of organic matter with the functions of inorganic matter, and has excellent high temperature resistance, thermal oxidation stability, weather resistance and electrical insulation properties, and is resistant to moisture, water, rust, cold and ozone, has good resistance to a variety of chemicals, is resistant to chemical corrosion, has good adhesion, flexibility and elasticity, and is one of the key components of silicone sealants.

[0011] As a preferred embodiment, the silane coupling agent is one or more of coupling agent KH-530, coupling agent KH-570 and coupling agent SI-335.

[0012] As a preferred embodiment, the catalyst I is isopropyl titanate.

[0013] As a preferred embodiment, the thermally conductive filler is one or more of microporous silicon powder, silicon nitride whiskers, zinc oxide and boron carbide.

[0014] As a preferred embodiment, the flame retardant is one or more of aluminum hydroxide, melamine, basic magnesium sulfate whisker and zinc borate surface-treated with silane coupling agent KH-590.

[0015] As a preferred embodiment, the adhesion promoter is γ-glycidyloxypropyl triethoxysilane.

[0016] As a preferred embodiment, the inhibitor is one or more of alkynyl cyclohexanol, 1-hexyn-3-ol, methyl tris(cyclohexynyloxy)silane, dimethyl butynedioate and phenylacetylene.

[0017] As a preferred embodiment, the catalyst II is one or more of chloroplatinic acid, platinum-divinyldiphenyldisiloxane complex and chloroplatinic acid-divinyltetramethyldisiloxane complex.

[0018] As a preferred embodiment, the anti-settling agent is fumed silica.

[0019] As a preferred embodiment, the reinforcing filler is one or more of nano calcium carbonate, graphene, aluminum silicate and talc.

[0020] As a preferred embodiment, the diluent is dimethyl silicone oil.

[0021] In order to solve the above technical problems, the second object of the present invention is to provide a method for preparing a high-adhesive silicone potting adhesive for LED display screens, comprising the following preparation steps: 1) Prepare base material: Weigh terminal hydroxyl vinyl silicone oil and catalyst I according to the formula, use anhydrous toluene as solvent, mix thoroughly, heat and stir to 100-120°C under nitrogen atmosphere, and drop a certain amount of silane coupling agent. After the dropwise addition is completed, react for 1 hour, distill under reduced pressure at 80°C for a period of time, stop heating, cool to room temperature, and then remove the vacuum to obtain vinyl silicone oil containing active groups; 2) Preparation of component A: weigh the base material, silicone resin, thermal conductive filler and flame retardant according to the formula, mix them evenly in a kneader, heat them to 80-100°C for 1 hour, and then heat them to 160-180°C and evacuate them for 2 hours to obtain component A; 3) Preparation of component B: According to the formula, hydrogen-containing silicone oil, adhesion promoter, inhibitor, catalyst II, anti-settling agent, reinforcing filler and diluent are weighed respectively and mixed evenly in a kneader, and then vacuumed at 110-130°C for 1 hour to obtain component B; 4) The component A and the component B are mixed evenly in a ratio of 1:1, placed in a vacuum oven for degassing for 10 minutes, and then cured at room temperature to obtain the high-adhesive silicone potting adhesive for the LED display. The silicone potting glue of the present invention uses hydroxyl-terminated vinyl silicone oil treated with a silane coupling agent as a base material and hydrogenated silicone oil as a crosslinking agent. Under the action of a platinum catalyst, the Si-H bond in the hydrogenated silicone oil and the C=C of the vinyl silicone oil undergo a silylation reaction to form a three-dimensional network structure elastomer, the elastomer has an active group, has relatively good tackiness to the substrate, and adds an organic silicone resin to introduce a stable and flexible Si-O chain into the cured structure, thereby scientifically optimizing the performance of the three-dimensional network structure elastomer. The silicone potting glue is matched with a thermal conductive filler, a flame retardant, an adhesion promoter, an anti-settling agent, a reinforcing filler, and a diluent, effectively optimizing the internal structure of the silicone potting glue, significantly enhancing its mechanical properties, improving the tensile strength and shear strength of the silicone potting glue, improving the bonding performance and processing performance of the silicone potting glue, making it have good fluidity, not easy to settle, having a high thermal conductivity and excellent mechanical properties, being more reliable and stable in responding to mechanical requirements under various environments, being able to meet the requirements of long-term use under high and low temperature environments, and having broad market prospects.

[0022] Beneficial effects of the present invention: 1. The present invention uses terminal hydroxyl vinyl silicone oil as a reaction raw material, and cross-links with a silane coupling agent through a condensation reaction under the catalysis of isopropyl titanate, so that the active group in the silane coupling agent is grafted to the chain end of the terminal hydroxyl vinyl silicone oil, thereby increasing the surface energy of the molecule, changing the current situation in which the silicone potting adhesive has poor bonding performance due to the presence of a large number of methyl groups on the surface of the molecular chain, effectively improving the bonding performance between the silicone potting adhesive and the substrate, and at the same time improving the mechanical properties of the silicone potting adhesive.

[0023] 2. Treated hydroxyl-terminated vinyl silicone oil is used as the base material, and the main reaction system is formed with hydrogen-containing silicone oil. Under the action of platinum catalyst, a silylation reaction occurs to form a three-dimensional network structure elastomer, and silicone resin is used as a reinforcing resin to effectively optimize the performance of silicone potting glue. At the same time, under the coordinated and synergistic effect of the thermal conductive filler, flame retardant, adhesion promoter, anti-settling agent, reinforcing filler, and diluent, on the basis of improving the bonding performance of silicone potting glue, its tensile strength and shear strength are effectively improved, so that the bonding shear strength of silicone potting glue is as high as 1.05-1.23MPa, the tensile strength reaches 2.34-3.45MPa, and the elongation at break reaches 157-175%.

[0024] 3. Silicone potting glue also has excellent flame retardancy, heat resistance, cold resistance and anti-settling properties, and its thermal conductivity is as high as 3.02-3.87W / It can effectively reduce the operating temperature of the LED chip so that it can maintain stable performance under different environmental conditions. However, its hardness and viscosity are moderate, which meets the relevant requirements of silicone sealant. It has good fluidity and is not easy to settle. It can effectively extend the service life of silicone potting glue and well meet the bonding needs of LED display screens in long-term complex outdoor environments. DETAILED DESCRIPTION

[0025] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Example 1 A high-adhesive silicone potting adhesive for an LED display screen comprises a component A and a component B, wherein the raw materials of the component A are prepared according to the following weight proportions: 100 parts of terminal hydroxyl vinyl silicone oil, 1 part of silane coupling agent KH-530, 0.1 parts of isopropyl titanate, 15 parts of anhydrous toluene, 80 parts of microporous silicon powder, 10 parts of basic magnesium sulfate whisker, and 20 parts of silicone resin.

[0027] The B component is prepared according to the following weight ratio: 5 parts of hydrogenated silicone oil, 2 parts of γ-glycidyloxypropyl triethoxysilane, 0.2 parts of phenylacetylene, 0.25 parts of chloroplatinic acid, 3 parts of fumed silica, 300 parts of talc, and 10 parts of dimethyl silicone oil.

[0028] A method for preparing a high-adhesive silicone potting adhesive for an LED display is as follows: 1) Prepare the base material: Weigh the hydroxy-terminated vinyl silicone oil with a vinyl content of 0.5% and a viscosity of 500cp and isopropyl titanate according to the formula, use anhydrous toluene as the solvent, mix them thoroughly, heat and stir to 100°C under a nitrogen atmosphere, and drop the silane coupling agent KH-530. After the dropwise addition is completed, react for 1 hour, distill under reduced pressure at 80°C for a period of time, stop heating, cool to room temperature, and then remove the vacuum to obtain vinyl silicone oil containing active groups; 2) Preparation of component A: weigh the base material, silicone resin, microporous silicon powder and basic magnesium sulfate whisker according to the formula, mix them evenly in a kneader, heat the mixture to 80°C for 1 hour, and then heat the mixture to 160°C for 2 hours to obtain component A; 3) Preparation of component B: According to the formula, hydrogen-containing silicone oil with a hydrogen content of 0.35% and a viscosity of 100cp, γ-glycidyloxypropyl triethoxysilane, phenylacetylene, chloroplatinic acid, fumed silica, talc, and dimethyl silicone oil were weighed respectively, mixed evenly in a kneader, and then vacuumed at 110°C for 1 hour to obtain component B; 4) The component A and the component B are mixed evenly in a ratio of 1:1, placed in a vacuum oven for degassing for 10 minutes, and then cured at room temperature to obtain the high-adhesive silicone potting adhesive for the LED display. Example 2 A high-adhesive silicone potting adhesive for an LED display screen comprises a component A and a component B, wherein the raw materials of the component A are prepared according to the following weight proportions: 100 parts of terminal hydroxyl vinyl silicone oil, 1.5 parts of silane coupling agent SI-335, 0.5 parts of isopropyl titanate, 15 parts of anhydrous toluene, 120 parts of silicon nitride whiskers, 18 parts of aluminum hydroxide, and 30 parts of silicone resin.

[0029] The B component is prepared according to the following weight ratio: 8 parts of hydrogenated silicone oil, 1 part of γ-glycidyloxypropyl triethoxysilane, 0.1 parts of 1-hexyn-3-ol, 0.2 parts of platinum-divinyldiphenyldisiloxane complex, 3 parts of fumed silica, 200 parts of aluminum silicate, and 8 parts of dimethyl silicone oil.

[0030] A method for preparing a high-adhesive silicone potting adhesive for an LED display is as follows: 1) Prepare the base material: Weigh the hydroxy-terminated vinyl silicone oil with a vinyl content of 0.12% and a viscosity of 2000cp and isopropyl titanate according to the formula, use anhydrous toluene as the solvent, mix them thoroughly, heat and stir to 120°C under a nitrogen atmosphere, and drop the silane coupling agent SI-335. After the dropwise addition is completed, react for 1 hour, distill under reduced pressure at 80°C for a period of time, stop heating, cool to room temperature, and then remove the vacuum to obtain vinyl silicone oil containing active groups; 2) Preparation of component A: weigh the base material, silicone resin, silicon nitride whisker and aluminum hydroxide according to the formula, mix them evenly in a kneader, heat the mixture to 90°C for 1 hour, and then heat the mixture to 165°C for 2 hours to obtain component A; 3) Preparation of component B: According to the formula, hydrogen-containing silicone oil with a hydrogen content of 0.25% and a viscosity of 80cp, γ-glycidyloxypropyl triethoxysilane, 1-hexyn-3-ol, platinum-divinyldiphenyldisiloxane complex, fumed silica, aluminum silicate, and dimethyl silicone oil were weighed respectively, mixed evenly in a kneader, and then vacuumed at 120°C for 1 hour to obtain component B; 4) The component A and the component B are mixed evenly in a ratio of 1:1, placed in a vacuum oven for degassing for 10 minutes, and then cured at room temperature to obtain the high-adhesive silicone potting adhesive for the LED display.

[0031] Example 3 A high-adhesive silicone potting adhesive for an LED display screen comprises a component A and a component B, wherein the raw materials of the component A are prepared according to the following weight proportions: 100 parts of terminal hydroxyl vinyl silicone oil, 2.5 parts of silane coupling agent KH-570, 1.5 parts of isopropyl titanate, 20 parts of anhydrous toluene, 80 parts of zinc oxide, 70 parts of boron carbide, 15 parts of zinc borate, 15 parts of basic magnesium sulfate whisker, and 25 parts of silicone resin.

[0032] The B component is prepared according to the following weight ratio: 10 parts of hydrogenated silicone oil, 3 parts of γ-glycidyloxypropyl triethoxysilane, 0.35 parts of methyl tri(cyclohexynyloxy)silane, 0.4 parts of chloroplatinic acid-divinyltetramethyldisiloxane complex, 5 parts of fumed silica, 400 parts of graphene, and 12 parts of dimethyl silicone oil.

[0033] A method for preparing a high-adhesive silicone potting adhesive for an LED display is as follows: 1) Prepare base material: Weigh hydroxy-terminated vinyl silicone oil with a vinyl content of 0.25% and a viscosity of 1500cp and isopropyl titanate according to the formula, use anhydrous toluene as solvent, mix thoroughly, heat and stir to 110°C under nitrogen atmosphere, and drop silane coupling agent KH-570. After the dropwise addition is completed, react for 1 hour, distill under reduced pressure at 80°C for a period of time, stop heating, cool to room temperature, and then remove the vacuum to obtain vinyl silicone oil containing active groups; 2) Preparation of component A: weigh the base material, silicone resin, zinc oxide, boron carbide, zinc borate, and basic magnesium sulfate whisker according to the formula, mix them evenly in a kneader, heat the mixture to 100° C. for 1 hour, and then heat the mixture to 170° C. for 2 hours to obtain component A; 3) Preparation of component B: According to the formula, hydrogen-containing silicone oil with a hydrogen content of 0.5% and a viscosity of 120cp, γ-glycidyloxypropyl triethoxysilane, methyl tri(cyclohexynyloxy)silane, chloroplatinic acid-divinyltetramethyldisiloxane complex, fumed silica, graphene, and dimethyl silicone oil were weighed respectively, mixed evenly in a kneader, and then vacuumed at 130°C for 1h to obtain component B; 4) The component A and the component B are mixed evenly in a ratio of 1:1, placed in a vacuum oven for degassing for 10 minutes, and then cured at room temperature to obtain the high-adhesive silicone potting adhesive for the LED display.

[0034] Example 4 A high-adhesive silicone potting adhesive for an LED display screen comprises a component A and a component B, wherein the raw materials of the component A are prepared according to the following weight proportions: 100 parts of terminal hydroxyl vinyl silicone oil, 2 parts of silane coupling agent KH-570, 1.5 parts of isopropyl titanate, 10 parts of anhydrous toluene, 60 parts of microporous silicon powder, 40 parts of zinc oxide, 15 parts of basic magnesium sulfate whisker, 10 parts of aluminum hydroxide, and 30 parts of silicone resin.

[0035] The B component is prepared according to the following weight ratio: 10 parts of hydrogenated silicone oil, 2 parts of γ-glycidyloxypropyl triethoxysilane, 0.1 parts of alkynyl cyclohexanol, 0.3 parts of chloroplatinic acid, 4 parts of fumed silica, 400 parts of nano calcium carbonate, and 10 parts of dimethyl silicone oil.

[0036] A method for preparing a high-adhesive silicone potting adhesive for an LED display is as follows: 1) Prepare the base material: Weigh the hydroxy-terminated vinyl silicone oil with a vinyl content of 0.28% and a viscosity of 500cp and isopropyl titanate according to the formula, use anhydrous toluene as the solvent, mix them thoroughly, heat and stir to 120°C under a nitrogen atmosphere, and drop the silane coupling agent KH-570. After the dropwise addition is completed, react for 1 hour, distill under reduced pressure at 80°C for a period of time, stop heating, cool to room temperature, and then remove the vacuum to obtain vinyl silicone oil containing active groups; 2) Preparation of component A: weigh the base material, silicone resin, microporous silicon powder, zinc oxide, basic magnesium sulfate whisker and aluminum hydroxide according to the formula, mix them evenly in a kneader, heat the mixture to 80°C for 1 hour, and then heat the mixture to 180°C for 2 hours to obtain component A; 3) Preparation of component B: According to the formula, hydrogen-containing silicone oil with a hydrogen content of 0.18% and a viscosity of 80cp, γ-glycidyloxypropyl triethoxysilane, alkynyl cyclohexanol, chloroplatinic acid, fumed silica, nano-calcium carbonate, and dimethyl silicone oil were weighed respectively, mixed evenly in a kneader, and then vacuumed at 130°C for 1 hour to obtain component B; 4) The component A and the component B are mixed evenly in a ratio of 1:1, placed in a vacuum oven for degassing for 10 minutes, and then cured at room temperature to obtain the high-adhesive silicone potting adhesive for the LED display.

[0037] Example 5 A high-adhesive silicone potting adhesive for an LED display screen comprises a component A and a component B, wherein the raw materials of the component A are prepared according to the following weight proportions: 100 parts of terminal hydroxyl vinyl silicone oil, 3 parts of silane coupling agent SI-335, 2 parts of isopropyl titanate, 25 parts of anhydrous toluene, 80 parts of silicon nitride whiskers, 100 parts of zinc oxide, 30 parts of melamine, and 28 parts of silicone resin.

[0038] The B component is prepared according to the following weight ratio: 12 parts of hydrogenated silicone oil, 3 parts of γ-glycidyloxypropyl triethoxysilane, 0.3 parts of dimethyl butynedioate, 0.4 parts of chloroplatinic acid-divinyltetramethyldisiloxane complex, 4 parts of fumed silica, 300 parts of aluminum silicate, and 12 parts of dimethyl silicone oil.

[0039] A method for preparing a high-adhesive silicone potting adhesive for an LED display is as follows: 1) Prepare the base material: Weigh the hydroxy-terminated vinyl silicone oil with a vinyl content of 0.4% and a viscosity of 1800cp and isopropyl titanate according to the formula, use anhydrous toluene as the solvent, mix them thoroughly, heat and stir to 115°C under a nitrogen atmosphere, and drop the silane coupling agent SI-335. After the dropwise addition is completed, react for 1 hour, distill under reduced pressure at 80°C for a period of time, stop heating, cool to room temperature, and then remove the vacuum to obtain vinyl silicone oil containing active groups; 2) Preparation of component A: weigh the base material, silicone resin, silicon nitride whisker, zinc oxide and melamine according to the formula, mix them evenly in a kneader, heat the mixture to 90°C for 1 hour, and then heat the mixture to 175°C for 2 hours to obtain component A; 3) Preparation of component B: According to the formula, hydrogen-containing silicone oil with a hydrogen content of 0.4% and a viscosity of 100cp, γ-glycidyloxypropyl triethoxysilane, dimethyl butynedioate, chloroplatinic acid-divinyltetramethyldisiloxane complex, fumed silica, aluminum silicate, and dimethyl silicone oil were weighed respectively, mixed evenly in a kneader, and then vacuumed at 120°C for 1 hour to obtain component B; 4) The component A and the component B are mixed evenly in a ratio of 1:1, placed in a vacuum oven for degassing for 10 minutes, and then cured at room temperature to obtain the high-adhesive silicone potting adhesive for the LED display.

[0040] Comparative Example 1 A high-adhesive silicone potting adhesive for an LED display screen comprises a component A and a component B, wherein the raw materials of the component A are prepared according to the following weight proportions: 100 parts of terminal hydroxyl vinyl silicone oil, 60 parts of microporous silicon powder, 40 parts of zinc oxide, 15 parts of basic magnesium sulfate whisker, 10 parts of aluminum hydroxide, and 30 parts of silicone resin.

[0041] The B component is prepared according to the following weight ratio: 10 parts of hydrogenated silicone oil, 2 parts of γ-glycidyloxypropyl triethoxysilane, 0.1 parts of alkynyl cyclohexanol, 0.3 parts of chloroplatinic acid, 4 parts of fumed silica, 400 parts of nano calcium carbonate, and 10 parts of dimethyl silicone oil.

[0042] A method for preparing a high-adhesive silicone potting adhesive for an LED display is as follows: 1) Preparation of component A: According to the formula, terminal hydroxyl vinyl silicone oil with a vinyl content of 0.28% and a viscosity of 500cp, silicone resin, microporous silicon powder, zinc oxide and basic magnesium sulfate whisker, and aluminum hydroxide were weighed respectively, mixed evenly in a kneader, heated to 80°C for 1h, and then heated to 180°C for 2h to obtain component A; 2) Preparation of component B: According to the formula, hydrogen-containing silicone oil with a hydrogen content of 0.18% and a viscosity of 80cp, γ-glycidyloxypropyl triethoxysilane, alkynyl cyclohexanol, chloroplatinic acid, fumed silica, nano-calcium carbonate, and dimethyl silicone oil were weighed respectively, mixed evenly in a kneader, and then vacuumed at 130°C for 1 hour to obtain component B; 3) The component A and the component B are mixed evenly in a ratio of 1:1, placed in a vacuum oven for degassing for 10 minutes, and then cured at room temperature to obtain the high-adhesive silicone potting adhesive for the LED display.

[0043] Comparative Example 2 A high-adhesive silicone potting adhesive for an LED display screen comprises a component A and a component B, wherein the raw materials of the component A are prepared according to the following weight proportions: 100 parts of terminal hydroxyl vinyl silicone oil, 2 parts of silane coupling agent KH-570, 1.5 parts of isopropyl titanate, 10 parts of anhydrous toluene, 60 parts of microporous silicon powder, 40 parts of zinc oxide, 15 parts of basic magnesium sulfate whisker, 10 parts of aluminum hydroxide, and 30 parts of silicone resin.

[0044] The B component is prepared according to the following weight ratio: 10 parts of hydrogenated silicone oil, 2 parts of liquid silicone rubber tackifier, 0.1 parts of alkynyl cyclohexanol, 0.3 parts of chloroplatinic acid, 4 parts of fumed silica, 400 parts of nano calcium carbonate, and 10 parts of dimethyl silicone oil.

[0045] A method for preparing a high-adhesive silicone potting adhesive for an LED display is as follows: 1) Prepare the base material: Weigh the hydroxy-terminated vinyl silicone oil with a vinyl content of 0.28% and a viscosity of 500cp and isopropyl titanate according to the formula, use anhydrous toluene as the solvent, mix them thoroughly, heat and stir to 120°C under a nitrogen atmosphere, and drop the silane coupling agent KH-570. After the dropwise addition is completed, react for 1 hour, distill under reduced pressure at 80°C for a period of time, stop heating, cool to room temperature, and then remove the vacuum to obtain vinyl silicone oil containing active groups; 2) Preparation of component A: weigh the base material, silicone resin, microporous silicon powder, zinc oxide, basic magnesium sulfate whisker and aluminum hydroxide according to the formula, mix them evenly in a kneader, heat the mixture to 80°C for 1 hour, and then heat the mixture to 180°C for 2 hours to obtain component A; 3) Preparation of component B: According to the formula, hydrogenated silicone oil with a hydrogen content of 0.18% and a viscosity of 80 cp, liquid silicone rubber tackifier with a refractive index of 1.46, alkynyl cyclohexanol, chloroplatinic acid, fumed silica, nano-calcium carbonate, and dimethyl silicone oil were weighed respectively, mixed evenly in a kneader, and then vacuumed at 130° C. for 1 hour to obtain component B; 4) The component A and the component B are mixed evenly in a ratio of 1:1, placed in a vacuum oven for degassing for 10 minutes, and then cured at room temperature to obtain the high-adhesive silicone potting adhesive for the LED display.

[0046] Comparative Example 3 A high-adhesive silicone potting adhesive for an LED display screen comprises a component A and a component B, wherein the raw materials of the component A are prepared according to the following weight proportions: 100 parts of terminal hydroxyl vinyl silicone oil, 2 parts of silane coupling agent KH-570, 1.5 parts of isopropyl titanate, 10 parts of anhydrous toluene, 60 parts of microporous silicon powder, 40 parts of zinc oxide, 15 parts of basic magnesium sulfate whiskers, and 10 parts of aluminum hydroxide.

[0047] The B component is prepared according to the following weight ratio: 10 parts of hydrogenated silicone oil, 2 parts of γ-glycidyloxypropyl triethoxysilane, 0.1 parts of alkynyl cyclohexanol, 0.3 parts of chloroplatinic acid, 4 parts of fumed silica, 400 parts of nano calcium carbonate, and 10 parts of dimethyl silicone oil.

[0048] A method for preparing a high-adhesive silicone potting adhesive for an LED display is as follows: 1) Prepare the base material: Weigh the hydroxy-terminated vinyl silicone oil with a vinyl content of 0.28% and a viscosity of 500cp and isopropyl titanate according to the formula, use anhydrous toluene as the solvent, mix them thoroughly, heat and stir to 120°C under a nitrogen atmosphere, and drop the silane coupling agent KH-570. After the dropwise addition is completed, react for 1 hour, distill under reduced pressure at 80°C for a period of time, stop heating, cool to room temperature, and then remove the vacuum to obtain vinyl silicone oil containing active groups; 2) Preparation of component A: weigh the base material, microporous silicon powder, zinc oxide, basic magnesium sulfate whisker and aluminum hydroxide according to the formula, mix them evenly in a kneader, heat the mixture to 80°C for 1 hour, and then heat the mixture to 180°C for 2 hours to obtain component A; 3) Preparation of component B: According to the formula, hydrogen-containing silicone oil with a hydrogen content of 0.18% and a viscosity of 80cp, γ-glycidyloxypropyl triethoxysilane, alkynyl cyclohexanol, chloroplatinic acid, fumed silica, nano-calcium carbonate, and dimethyl silicone oil were weighed respectively, mixed evenly in a kneader, and then vacuumed at 130°C for 1 hour to obtain component B; 4) The component A and the component B are mixed evenly in a ratio of 1:1, placed in a vacuum oven for degassing for 10 minutes, and then cured at room temperature to obtain the high-adhesive silicone potting adhesive for the LED display.

[0049] Component A and component B of the silicone potting adhesive prepared in Examples 1-5 and Comparative Examples 1-3 were mixed evenly in a ratio of 1:1, placed in a vacuum oven for degassing for 10 minutes, poured into a mold for curing at room temperature, and then removed from the mold to prepare samples for the following performance tests.

[0050] Test Example 1 Adhesion Performance Test First, the surface of the substrate was treated with isopropyl alcohol, and then the silicone potting sample was prepared according to the standard. After the potting, it was placed steadily and completely cured under different conditions. The bonding area was 25mm×12.5mm and the thickness was 2mm.

[0051] GB / T13936-1992 standard was used to determine the bonding shear strength between the addition type silicone potting adhesive and the substrate, and the bonding performance of the silicone potting adhesive was evaluated. The results are shown in Table 1.

[0052] Test Example 2 Mechanical Properties Test Referring to GB / T 528-2009 standard, the CMT-4304 universal tensile testing machine produced by Shenzhen Xinsansi Metrology Technology Co., Ltd. was used to measure the tensile strength and elongation at break of the silicone potting adhesive. The tensile speed was 200 mm / min, and the mechanical properties of the silicone adhesive were evaluated. The results are shown in Table 1.

[0053] Test Example 3 Hardness Test The hardness of the silicone potting compound was measured according to GB / T 531-2009 standard. The results are shown in Table 1.

[0054] Test Example 4 Viscosity Test According to GB / T 2794-2013 standard, the viscosity of silicone potting adhesive was measured by a rotational viscometer at room temperature. The results are shown in Table 1.

[0055] Table 1 It can be seen from the above experimental results and data that the silicone sealants prepared in Examples 1-5 of the present invention have good shear strength, tensile strength and elongation at break, and their hardness and viscosity are moderate, which meet the relevant requirements of silicone sealants, and have excellent bonding strength. The comprehensive performance is significantly better than that of the silicone sealants prepared in Comparative Examples 1-3, and after the terminal hydroxyl vinyl silicone oil is treated with a silane coupling agent and an organic silicone resin and an adhesion promoter are added, its mechanical properties and bonding properties are significantly improved, which meets the high performance requirements of silicone sealants in the electronic industry such as LED display screens.

[0056] Test Example 5 Flame retardant properties The flame retardant properties of silicone potting adhesive were tested by the vertical combustion method according to GB / T10707-2008 standard. The sample size was 130 mm × 13 mm × 3 mm. The results are shown in Table 2.

[0057] Test Example 6 Thermal Conductivity Test The cured silicone potting glue samples were made into standard samples with a diameter of 20 mm and a thickness of 2 mm. Referring to ASTM D5470 (Chinese version of Standard Test Method for Thermal Transfer Properties of Thermally Conductive Electrical Insulating Materials), the thermal conductivity of the silicone potting glue was tested using a DRL-III heat flow method thermal conductivity coefficient tester to evaluate the thermal conductivity of the silicone potting glue. The results are shown in Table 2.

[0058] Test Example 7 High and Low Temperature Resistance Test The cured silicone potting glue sample was placed in a hot and cold shock test chamber. The operation of placing it at a low temperature of -40°C for 30 minutes and then placing it at a high temperature of 100°C for 30 minutes was regarded as a cycle. After a total of 1000 cycles, the surface was observed for bubbling and cracks. The results are shown in Table 2.

[0059] Test Example 8 Anti-settling performance test Component A and component B of each embodiment and comparative example were taken as experimental samples, 20 samples of each component were set, each sample was 50g, the samples were placed in 100mL plastic cups, and stored at room temperature for 9 months. After standing, one sample in each group was selected every 15 days, and the bottom of the plastic cup was scraped with a scraper to observe whether there was sedimentation at the bottom. After each test, the corresponding sample was discarded, and other samples were tested next time. The results are shown in Table 2.

[0060] Table 2 It can be seen from the above experimental results and data that the silicone adhesive prepared in Examples 1-5 of the present invention has flame retardancy, heat resistance, cold resistance and anti-settling properties, has a high thermal conductivity, can effectively reduce the operating temperature of the LED chip, is more reliable and stable in dealing with different complex environments, has a wider temperature application range, and its stability is significantly better than the silicone potting glue prepared in Comparative Examples 1-3, can effectively extend the service life of the silicone potting glue, and meet the high-stability bonding requirements of the electronic industry such as LED display screens.

[0061] Finally, it should be emphasized that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-adhesive silicone potting compound for LED display screens, comprising component A and component B, wherein component A comprises the following raw materials in parts by weight: 100 parts of hydroxy-terminated vinyl silicone oil; 1-3 parts of silane coupling agent; Catalyst I 0.1-2 parts; Thermal conductive filler 80-200 parts; Flame retardant 10-30 parts; 20-30 parts of silicone resin; The B component includes the following raw materials: 2-15 parts of hydrogen silicone oil; 1-3 parts of adhesion promoter; Inhibitor 0.1-0.4 parts; Catalyst II 0.1-0.5 parts; 1-5 parts of anti-settling agent; 200-500 parts of reinforcing filler; 8-12 parts of diluent.

2. The high-adhesive silicone potting adhesive for LED display screen according to claim 1, characterized in that: The mass content of vinyl in the hydroxy-terminated vinyl silicone oil is 0.1-0.5%, and the viscosity is 500cp-2000cp; the mass content of hydrogen in the hydrogen-containing silicone oil is 0.15-0.5%, and the viscosity is 40-200cp.

3. The high-adhesive silicone potting adhesive for LED display screen according to claim 1, characterized in that: The silane coupling agent is one or more of coupling agent KH-530, coupling agent KH-570 and coupling agent SI-335.

4. The high-adhesive silicone potting adhesive for LED display screen according to claim 1, characterized in that: The catalyst I is isopropyl titanate; the catalyst II is one or more of chloroplatinic acid, platinum-divinyldiphenyldisiloxane complex and chloroplatinic acid-divinyltetramethyldisiloxane complex.

5. The high-adhesive silicone potting adhesive for LED display screen according to claim 1, characterized in that: The thermal conductive filler is one or more of microporous silicon powder, silicon nitride whisker, zinc oxide and boron carbide.

6. The high-adhesive silicone potting adhesive for LED display screen according to claim 1, characterized in that: The flame retardant is one or more of aluminum hydroxide, melamine, basic magnesium sulfate whisker, and zinc borate surface-treated with silane coupling agent KH-590.

7. The high-adhesive silicone potting adhesive for LED display screen according to claim 1, characterized in that: The adhesion promoter is γ-glycidyloxypropyl triethoxysilane; the anti-settling agent is fumed silica; and the diluent is dimethyl silicone oil.

8. The high-adhesive silicone potting adhesive for LED display screen according to claim 1, characterized in that: The inhibitor is one or more of alkynyl cyclohexanol, 1-hexyn-3-ol, methyl tris(cyclohexynyloxy)silane, dimethyl butynedioate and phenylacetylene.

9. The high-adhesive silicone potting adhesive for LED display screen according to claim 1, characterized in that: The reinforcing filler is one or more of nano calcium carbonate, graphene, aluminum silicate and talc; the organic silicone resin is MQ silicone resin containing vinyl functional groups, and the mass fraction of vinyl groups is 3%.

10. A method for preparing a high-adhesive silicone potting compound for LED display screens, characterized in that: The steps include: 1) Prepare base material: Weigh terminal hydroxyl vinyl silicone oil and catalyst I according to the formula, use anhydrous toluene as solvent, mix thoroughly, heat and stir to 100-120°C under nitrogen atmosphere, and drop a certain amount of silane coupling agent. After the dropwise addition is completed, react for 1 hour, distill under reduced pressure at 80°C for a period of time, stop heating, cool to room temperature, and then remove the vacuum to obtain vinyl silicone oil containing active groups; 2) Preparation of component A: weigh the base material, silicone resin, thermal conductive filler and flame retardant according to the formula, mix them evenly in a kneader, heat them to 80-100°C for 1 hour, and then heat them to 160-180°C and evacuate them for 2 hours to obtain component A; 3) Preparation of component B: According to the formula, hydrogen-containing silicone oil, adhesion promoter, inhibitor, catalyst II, anti-settling agent, reinforcing filler and diluent are weighed respectively and mixed evenly in a kneader, and then vacuumed at 110-130°C for 1 hour to obtain component B; 4) The component A and the component B are mixed evenly in a ratio of 1:1, placed in a vacuum oven for degassing for 10 minutes, and then cured at room temperature to obtain the high-adhesive silicone potting adhesive for the LED display.

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