Single-component bonding type low-temperature-resistant silica gel as well as preparation method and application thereof

Abstract

The invention provides single-component adhesive low-temperature-resistant silica gel as well as a preparation method and application thereof. The single-component adhesive low-temperature-resistant silica gel comprises the following components in parts by mass: 100 parts of phenyl vinyl silicone oil; 25 to 40 parts of terminal hydrogen-containing silicone oil; 0.2 to 1 part of side hydrogen-containing phenyl silicone oil; 0.2 to 0.5 part of a catalyst; and 1-4 parts of a coupling agent. The single-component bonding type low-temperature-resistant silica gel disclosed by the invention is simple to prepare, can be completely cured within 1 hour at the temperature of 65 DEG C or above, is convenient to use, has excellent low-temperature resistance, and can still keep good elasticity when the temperature is as low as-70 DEG C; the single-component bonding type low-temperature-resistant silica gel disclosed by the invention can be used as an optical adhesive for an electronic display screen, and can be directly poured between the display screen and a touch screen after being extruded, so that no bubble is generated after the silica gel is cured, and prime-coat-free bonding between the display screens can be realized.

Description

Technical Field

[0001] The invention relates to the technical field of adhesives, and in particular to a single-component bonding type low-temperature resistant silicone gel and a preparation method and application thereof. Background Art

[0002] Optical adhesives are polymer substances with optical properties similar to those of optical parts and excellent bonding properties. Optical adhesives can bond two or more optical parts into optical components that meet the requirements of optical path design. Optical adhesives can be used to bond protective glass such as high-precision optical scales and filters. As an optical adhesive for electronic display screens, the advantage of polyurethane adhesives is that they are low in cost and have a widely used laminating surface, but they are not moisture-resistant enough, and have poor refractive index and yellowing resistance, so they are rarely used in high-end screen devices. Epoxy optical adhesives are one of the commonly used materials for UV-curing adhesives. They have high lamination strength and good tolerance, but cationic curing may cause etching of indium tin oxide (ITO) touch sensors, which limits their application in related areas. Acrylate optical adhesives generally refer to acrylic optical pressure-sensitive adhesives, which have good inherent optical transparency, low cost, strong bonding strength, short bonding time, and good weather resistance. They are widely studied and used in the field of screen bonding, especially in the current cutting-edge flexible folding screens. However, acrylic resins also have related problems such as poor shrinkage. Silicone optical adhesives are widely used in the field of high-end pressure-sensitive adhesives and have advantages that other types of adhesives do not have. How to find a silicone gel that has excellent low-temperature resistance and can be easily used in electronic display screens is a technical problem that needs to be solved urgently. Summary of the invention

[0003] In view of the above problems, the present invention provides a one-component adhesive low-temperature resistant silicone gel and a preparation method and application thereof.

[0004] On the one hand, the present invention provides a one-component adhesive low-temperature resistant silicone gel, which comprises the following components in parts by mass:

[0005]

[0006]

[0007] Optionally, 1 to 2 parts of a co-solvent are also included, and the structural formula of the co-solvent is as follows:

[0008]

[0009] Among them, n is 2 to 6.

[0010] Optionally, the phenyl vinyl silicone oil is one or more selected from phenyl vinyl silicone oils having a vinyl content of 0.0175 to 0.05 mol / 100 g and a phenyl molar content of 10 to 30%;

[0011] Preferably, the molar content of phenyl groups in the phenyl vinyl silicone oil is 10 to 15%.

[0012] Optionally, the terminal hydrogen-containing silicone oil is one or more selected from terminal hydrogen-containing silicone oils having an active hydrogen mass fraction of 0.06 to 0.08%.

[0013] Optionally, the mass fraction of active hydrogen in the side hydrogen-containing phenyl silicone oil is 0.01-0.1%, the molar content of phenyl is 10-30%, and the molar content of phenyl is preferably 10-15%.

[0014] Optionally, the catalyst is a single-component platinum catalyst.

[0015] Optionally, the mass of the catalyst is 2000-5000ppm of the mass of phenyl vinyl silicone oil.

[0016] Optionally, the coupling agent is phenyl trimethoxy silicone oil, and the mass proportion of the coupling agent is 3 to 4 parts.

[0017] On the other hand, the present invention also provides a method for preparing a single-component adhesive low-temperature resistant silicone gel, comprising:

[0018] The following components in parts by mass are mixed and degassed to obtain a single-component adhesive low-temperature resistant silicone gel:

[0019]

[0020] On the other hand, the present invention also provides an application of a one-component adhesive low-temperature resistant silicone gel, wherein the one-component adhesive low-temperature resistant silicone gel is poured between the touch screen and the display screen and then cured.

[0021] Beneficial effects:

[0022] (1) The one-component adhesive low-temperature resistant silicone gel of the present invention is easy to prepare and can be completely cured within 1 hour at a temperature above 65°C. It is easy to use and has excellent low-temperature resistance. It can maintain good elasticity at a temperature as low as -70°C.

[0023] (2) The one-component adhesive low-temperature resistant silicone gel of the present invention can be used as an optical adhesive for electronic display screens. After extrusion, it can be directly poured between the display screen and the touch screen, so that no bubbles are generated after curing, and primer-free bonding between display screens can be achieved;

[0024] (3) The one-component adhesive low-temperature resistant silicone gel of the present invention greatly improves the light transmittance of the silicone gel after curing by adding a co-solvent with a specific structure, thereby obtaining a silicone gel with excellent comprehensive performance. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below through examples. Through these examples, the features and advantages of the present invention will become clearer and more specific.

[0026] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0027] Terminology

[0028] In the present invention, the term "HMTETA" means 1,1,4,7,10,10-hexamethyltriethylenetetramine;

[0029] In the present invention, the term "THF" means tetrahydrofuran.

[0030] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0031] On the one hand, the present invention provides a one-component adhesive low-temperature resistant silicone gel, which comprises the following components in parts by mass:

[0032]

[0033] It should be noted that silicone oil usually refers to linear polysiloxane products that remain in liquid state at room temperature, which are generally divided into two categories: methyl silicone oil and modified silicone oil. The most commonly used silicone oil is methyl silicone oil, also known as ordinary silicone oil, whose organic groups are all methyl, and its structure can be shown as follows: Methyl silicone oil has good chemical stability, insulation, and good hydrophobicity. Phenyl vinyl silicone oil refers to silicone oil containing phenyl and vinyl; terminal hydrogen silicone oil refers to silicone oil containing Si-H at the end, and side hydrogen phenyl silicone oil refers to silicone oil containing phenyl and Si-H at the side.

[0034] It should be noted that in the one-component adhesive low-temperature resistant silicone gel of the present invention, phenyl vinyl silicone oil, terminal hydrogen silicone oil, side hydrogen phenyl silicone oil, catalyst and coupling agent are compounded according to the above-mentioned mass parts, and the components synergize with each other. It can be cured in 1 hour at ≥65°C, and can be directly poured between the display screen and the touch screen. It can achieve no bubble generation after curing, and can realize primer-free bonding between the display screens. It has excellent low-temperature resistance and can maintain good elasticity at temperatures as low as -70°C.

[0035] In a preferred embodiment of the aforementioned one-component adhesive low-temperature resistant silicone gel of the present invention, 1 to 2 parts of a co-solvent are further included, and the structural formula of the co-solvent is as follows:

[0036]

[0037] Among them, n is 2 to 6.

[0038] It should be noted that after years of research and development experiments, the inventors of the present application unexpectedly discovered that compounding the cosolvent of the above structure with phenyl vinyl silicone oil, terminal hydrogen silicone oil, side hydrogen phenyl silicone oil, catalyst, and coupling agent can effectively improve the compatibility of the substances in the system, thereby significantly improving the transmittance of the phenyl silicone gel after curing. At this time, the cosolvent and other components play a good synergistic role, resulting in a single-component adhesive low-temperature resistant silicone gel with better comprehensive performance.

[0039] The preparation method of the above structural co-solvent may include:

[0040] PDMS 65 -Br, monomer B, HMTETA and anisole are added to the polymerization tube in sequence, and the polymerization tube is placed in liquid nitrogen and frozen under a nitrogen-filled state. After the sample is completely frozen, vacuumize it, and then place it in warm water to stir and thaw the sample under a nitrogen-filled state, and then repeat the above operation three times. CuBr is then added under a liquid nitrogen frozen state, and then freezing-vacuuming-nitrogen is performed. Repeat the above operation three times, and the tube is sealed with an alcohol burner under a frozen and vacuumed state of the sample. After the reaction system is melted at room temperature, it is placed in an oil bath for polymerization. In the experiment, the polymerization degree is controlled by adjusting the feeding ratio of the monomer and the macromolecular initiator. After the reaction is completed, the reaction is quenched with liquid nitrogen. The obtained polymerization system is diluted with THF, and then the copper salt therein is removed with a neutral alumina column, and then a large amount of methanol is precipitated three times, and the orange-yellow powder product can be obtained by filtration.

[0041] PDMS 65 The structural formula of -Br is The synthesis process is as follows: add monohydroxyl-terminated PDMS in a round-bottom flask in sequence 65-OH, triethylamine and anhydrous THF, after stirring and dissolving, place in an ice-water bath to cool, and slowly drop the mixed solution of bromoisobutyryl bromide and anhydrous THF into the above-mentioned round-bottom flask. After the addition is completed, continue to react in an ice-water bath, then remove the ice-water bath, and continue to react at room temperature. After the reaction is completed, filter and remove the triethylamine salt to obtain a clear solution, spin off THF and then dissolve the obtained colorless turbid liquid with dichloromethane, then wash with saturated sodium bicarbonate solution, and the obtained organic phase is dried over anhydrous sodium sulfate. Spin off dichloromethane from the dried organic phase. Dissolve the product with THF and slowly drop it into methanol (it is best to place methanol in an elongated container, such as a chromatography column, so that the crude product can fully contact with methanol and remove impurities therein), the product will be layered with the methanol solution and stand still on the lower floor, repeat the above operation, and obtain a colorless and transparent liquid, which is vacuum dried overnight.

[0042] The structural formula of monomer B is The synthesis process is:

[0043] Add 300-700 g of hydroxyl-terminated low-polymerization phenylsiloxane (Henan Tianfu Chemical Co., Ltd., CAS No.: 80801-30-5) and 150-350 g of methylcyclosiloxane into a flask equipped with a thermometer and a stirrer. Add 60-100g vinyl siloxane capping agent and 2-3g of catalyst (concentrated H2SO4), heat the mixture to 150-180°C, stir thoroughly until translucent, then add 2-5g of sodium ethoxide, continue stirring for 6-10 hours to obtain a reaction solution. Cool the reaction solution to room temperature, add 15-35g of sodium bicarbonate, continue stirring for 2-5 hours, then add 20-30g of potassium carbonate, stir for 2-5 hours, and then filter 2-4 times to obtain a filtrate. Place the filtrate under vacuum at 160-180°C to remove low-boiling substances, and finally obtain monomer B.

[0044] In one embodiment of the aforementioned one-component adhesive low-temperature resistant silicone gel of the present invention, the phenyl vinyl silicone oil is one or more selected from phenyl vinyl silicone oils having a vinyl content of 0.0175 to 0.05 mol / 100 g and a phenyl molar content of 10 to 30%;

[0045] Preferably, the molar content of phenyl groups in the phenyl vinyl silicone oil is 10 to 15%.

[0046] It should be noted that the above-mentioned phenyl vinyl silicone oil is compounded with terminal hydrogen silicone oil, side hydrogen phenyl silicone oil, catalyst and coupling agent, and the single-component adhesive low-temperature resistant silicone gel can obtain better performance. In particular, when the phenyl molar content of the phenyl vinyl silicone oil is controlled to be 10-15%, the low-temperature resistance of the silicone gel can be further improved.

[0047] In another embodiment of the aforementioned one-component adhesive low-temperature resistant silicone gel of the present invention, the terminal hydrogen-containing silicone oil is one or more selected from terminal hydrogen-containing silicone oils having an active hydrogen mass fraction of 0.06 to 0.08%.

[0048] It should be noted that compounding terminal hydrogen-containing silicone oil with an active hydrogen mass fraction of 0.06-0.08% with the other components mentioned above can improve the curing performance, low temperature resistance and other properties of the single-component adhesive low-temperature resistant silicone gel.

[0049] In another embodiment of the aforementioned one-component adhesive low-temperature resistant silicone gel of the present invention, the mass fraction of active hydrogen in the side hydrogen-containing phenyl silicone oil is 0.01-0.1%, the molar content of phenyl is 10-30%, and the molar content of phenyl is preferably 10-15%.

[0050] It should be noted that, under the premise of controlling the vinyl content and phenyl molar content of the phenyl vinyl silicone oil and the active hydrogen mass fraction of the terminal hydrogenated silicone oil as above, controlling the active hydrogen mass fraction and phenyl molar content of the side hydrogenated phenyl silicone oil as above can further improve the comprehensive performance of the one-component adhesive type low-temperature resistant silicone gel. In particular, when the phenyl molar content in the side hydrogenated phenyl silicone oil is preferably controlled as mentioned above, the low-temperature resistance of the silicone gel can be further improved.

[0051] In one embodiment of the aforementioned one-component adhesive low-temperature resistant silicone gel of the present invention, the catalyst is a one-component platinum catalyst.

[0052] In one embodiment of the aforementioned one-component adhesive low-temperature resistant silicone gel of the present invention, the mass of the catalyst is 2000 to 5000 ppm of the mass of the phenyl vinyl silicone oil.

[0053] It should be noted that in the one-component adhesive low-temperature resistant silicone gel of the present invention, a one-component platinum catalyst is used as a catalyst and the amount of the catalyst is controlled as above, so that a one-component adhesive low-temperature resistant silicone gel with excellent performance can be obtained.

[0054] In one embodiment of the aforementioned one-component adhesive low-temperature resistant silicone gel of the present invention, the coupling agent is phenyl trimethoxy silicone oil, and the mass fraction of the coupling agent is 3 to 4 parts.

[0055] It should be noted that in the one-component adhesive low-temperature resistant silicone gel of the present invention, phenyl trimethoxy silicone oil is used as a coupling agent, and the mass portion of the coupling agent is controlled to be 3 to 4 parts, which can well realize primer-free bonding between display screens and achieve good bonding, and the coupling agent and other components can synergize well, thereby improving the comprehensive performance of the one-component adhesive low-temperature resistant silicone gel.

[0056] On the other hand, the present invention also provides a method for preparing a single-component adhesive low-temperature resistant silicone gel, comprising:

[0057] The following components in parts by mass are mixed and degassed to obtain a single-component adhesive low-temperature resistant silicone gel:

[0058]

[0059] It should be noted that by compounding phenyl vinyl silicone oil, terminal hydrogen silicone oil, side hydrogen phenyl silicone oil, catalyst and coupling agent in the above-mentioned mass fractions, a single-component adhesive low-temperature resistant silicone gel with excellent low-temperature resistance and curing performance can be prepared through mixing and degassing.

[0060] On the other hand, the present invention also provides an application of a one-component adhesive low-temperature resistant silicone gel, wherein the one-component adhesive low-temperature resistant silicone gel is poured between the touch screen and the display screen and then cured.

[0061] It should be noted that the phenyl vinyl silicone oil, terminal hydrogen silicone oil, side hydrogen phenyl silicone oil, catalyst and coupling agent in the aforementioned one-component adhesive type low-temperature resistant silicone gel are compounded in the above-mentioned mass fractions, and the components synergize with each other. The one-component adhesive type low-temperature resistant silicone gel can be used as an optical adhesive for electronic display screens. After extrusion, it can be directly poured between the display screen and the touch screen. It can be cured in 1 hour at ≥65°C, and no bubbles can be generated after curing. Primer-free bonding between display screens can be achieved. It is very convenient to use and has excellent comprehensive performance.

[0062] The present invention is further described in detail by way of examples below, but the present invention is not limited thereto. In the following examples, unless otherwise specified, the experimental instruments and raw materials involved are all commercially available products.

[0063] The specific types of phenyl vinyl silicone oil can be distinguished by the vinyl content and phenyl molar content marked on the reagent bottle;

[0064] The specific model of end-hydrogenated silicone oil can be distinguished by the mass fraction of active hydrogen marked on the reagent bottle;

[0065] The specific models of side hydrogen-containing phenyl silicone oil can be distinguished by the active hydrogen mass fraction and phenyl molar content marked on the reagent bottle.

[0066] Example 1

[0067]

[0068] In this embodiment:

[0069] The phenyl vinyl silicone oil used had a vinyl content of 0.02 mol / 100 g and a phenyl molar content of 10%, and was purchased from Shandong Dayi Chemical Co., Ltd. with a brand name of DY-PV401-500;

[0070] The mass fraction of active hydrogen in the end-hydrogenated silicone oil is 0.06%, purchased from Runhe, with the brand name RH-DH07;

[0071] The mass fraction of active hydrogen in the side hydrogen-containing phenyl silicone oil is 0.01%, the molar content of phenyl is 10%, and it is purchased from Shandong Dayi Chemical Co., Ltd. with the brand name DY-PH212;

[0072] The catalyst is chloroplatinic acid;

[0073] The coupling agent is phenyl trimethoxy silicone oil, purchased from Jianghan New Materials, with the brand name JH-N610.

[0074] The preparation method of the one-component adhesive low-temperature resistant silicone gel is as follows:

[0075] The above materials were weighed by mass and placed in a vacuum rotary degassing machine for vacuum rotary degassing at a speed of 2000 r / min and a vacuum degree of -900 mbar for 1 minute to obtain a single-component adhesive low-temperature resistant silicone gel.

[0076] Example 2

[0077]

[0078] In this embodiment:

[0079] The phenyl vinyl silicone oil used has a vinyl content of 0.03 mol / 100 g and a phenyl molar content of 15%, and was purchased from Anhui IOTA Silicone Oil Co., Ltd. with a brand name of IOTA252;

[0080] The mass fraction of active hydrogen in the end-hydrogenated silicone oil is 0.06%, purchased from Runhe, with the brand name RH-DH07;

[0081] The mass fraction of active hydrogen in the side hydrogen-containing phenyl silicone oil is 0.04%, the molar content of phenyl is 15%, and it is purchased from Shandong Dayi Chemical Co., Ltd. with the brand name DY-PH212;

[0082] The catalyst is chloroplatinic acid;

[0083] The coupling agent is phenyl trimethoxy silicone oil, purchased from Jianghan New Materials, with the brand name JH-N610.

[0084] The preparation method of the one-component adhesive low-temperature resistant silicone gel is the same as that of Example 1.

[0085] Example 3

[0086]

[0087]

[0088] In this embodiment:

[0089] The phenyl vinyl silicone oil used has a vinyl content of 0.04 mol / 100 g and a phenyl molar content of 20%, and is purchased from Anhui IOTA Silicone Oil Co., Ltd. with a brand name of IOTA252;

[0090] The mass fraction of active hydrogen in the end-hydrogenated silicone oil is 0.08%, purchased from Runhe, with the brand name RH-DH07;

[0091] The mass fraction of active hydrogen in the side hydrogen-containing phenyl silicone oil is 0.05%, the molar content of phenyl is 20%, and it is purchased from Shandong Dayi Chemical Co., Ltd., brand DY-PH212;

[0092] The catalyst is chloroplatinic acid;

[0093] The coupling agent is phenyl trimethoxy silicone oil, purchased from Jianghan New Materials, with the brand name JH-N610.

[0094] The preparation method of the one-component adhesive low-temperature resistant silicone gel is the same as that of Example 1.

[0095] Example 4

[0096]

[0097] In this embodiment:

[0098] The phenyl vinyl silicone oil used has a vinyl content of 0.05 mol / 100 g and a phenyl molar content of 30%, and was purchased from Anhui IOTA Silicone Oil Co., Ltd. with a brand name of IOTA252;

[0099] The mass fraction of active hydrogen in the end-hydrogenated silicone oil is 0.08%, purchased from Runhe, with the brand name RH-DH07;

[0100] The mass fraction of active hydrogen in the side hydrogen-containing phenyl silicone oil is 0.1%, the molar content of phenyl is 30%, and it is purchased from Shandong Dayi Chemical Co., Ltd. with the brand name DY-PH212;

[0101] The catalyst is chloroplatinic acid;

[0102] The coupling agent is phenyl trimethoxy silicone oil, purchased from Jianghan New Materials, with the brand name JH-N610.

[0103] The preparation method of the one-component adhesive low-temperature resistant silicone gel is the same as that of Example 1.

[0104] Example 5

[0105] A one-component adhesive low-temperature resistant silicone gel was prepared according to the component formula and method of Example 3, except that:

[0106] It also contains 1 part of co-solvent;

[0107] The structural formula of the cosolvent is Where n is 2.

[0108] The synthesis process of the cosolvent is as follows:

[0109] PDMS 65 -Br (20.0mg, 4.16μmol), monomer B (530mg, 0.208mmol), HMTETA (4.00mg, 4.00μL) and 500μL anisole were added to the polymerization tube in sequence, and the polymerization tube was placed in liquid nitrogen for freezing under nitrogen filling state, vacuumed after the sample was completely frozen, and then placed in warm water for stirring and thawing the sample under nitrogen filling state, and then the above operation was repeated three times, and then 4.12mgCuBr was added under liquid nitrogen freezing state, and then freezing-vacuuming-nitrogen filling was performed, and the above operation was repeated three times, and the tube was sealed with an alcohol burner under the state of sample freezing and vacuuming. After the reaction system was melted at room temperature, it was placed in an 80℃ oil bath for polymerization. In the experiment, the polymerization degree was controlled by adjusting the feeding ratio of monomer and macromolecular initiator. After the reaction was completed, the reaction was quenched with liquid nitrogen. The obtained polymerization system was diluted with 10mLTHF, and then the copper salt therein was removed with a neutral alumina column, and then precipitated with a large amount of methanol three times, and the orange-yellow powder product was obtained by filtration. Through nuclear magnetic hydrogen spectrum and other tests, it was found that the structure of the synthesized product was the above structural formula.

[0110] PDMS 65 The structural formula of -Br is The synthesis process is as follows: add monohydroxyl-terminated PDMS in a 250 mL round-bottom flask in sequence: 65-OH (10.0 g, 2.14 mmol, purchased from Bailingwei Technology Co., Ltd.), triethylamine (0.428 g, 4.28 mmol) and 100 mL of anhydrous THF were stirred and dissolved, and then placed in an ice-water bath for cooling. A mixture of bromoisobutyryl bromide (0.984 g, 4.28 mmol) and 20 mL of anhydrous THF was slowly dripped into the above round-bottom flask. After the addition was completed, the reaction was continued in the ice-water bath for 1 h, and then the ice-water bath was removed and the reaction was continued at room temperature for 48 h. After the reaction was completed, the triethylamine salt was filtered to obtain a clear solution, and the THF was removed by spinning, and then the colorless turbid liquid was dissolved with 150 mL of dichloromethane, and then washed with a saturated sodium bicarbonate solution 3 times, and the obtained organic phase was dried with anhydrous sodium sulfate. The dried organic phase was spin-dried to remove dichloromethane. Dissolve the product in 10 mL of THF and slowly drip it into 150 mL of methanol (it is best to place the methanol in a slender container, such as a chromatography column, so that the crude product can fully contact with the methanol and remove impurities therein). The product will separate from the methanol solution and stay in the lower layer. Repeat the above operation 5 times to obtain a colorless and transparent liquid, which is dried in vacuo at 60°C overnight.

[0111] The structural formula of monomer B is The synthesis process is:

[0112] Add 500g of hydroxyl-terminated low-polymerization phenylsiloxane (Henan Tianfu Chemical Co., Ltd., CAS No.: 80801-30-5) and 200g of methylcyclosiloxane into a flask equipped with a thermometer and a stirrer. Add 80g vinyl siloxane capping agent and 2.8g of catalyst (concentrated H2SO4), heat the mixture to 150-180°C, stir thoroughly until translucent, then add 3g of sodium ethoxide, continue stirring for 6-10 hours to obtain a reaction solution. Cool the reaction solution to room temperature, add 20g of sodium bicarbonate, continue stirring for 2-5 hours, then add 28g of potassium carbonate, stir for 2-5 hours, and then filter 2-4 times to obtain a filtrate. Place the filtrate under vacuum conditions at 160-180°C to remove low-boiling substances, and finally obtain monomer B.

[0113] Example 6

[0114] A one-component adhesive low-temperature resistant silicone gel was prepared according to the component formula and method of Example 4, except that:

[0115] The invention also contains 1 part of a co-solvent, which is the same as the co-solvent in Example 5.

[0116] Example 7

[0117] A one-component adhesive low-temperature resistant silicone gel was prepared according to the method of Example 1, with the following changes:

[0118] The coupling agent is 4 parts.

[0119] Example 8

[0120] A one-component adhesive low-temperature resistant silicone gel was prepared according to the method of Example 2, with the following changes:

[0121] The coupling agent is 3 parts.

[0122] Example 9

[0123] A one-component adhesive low-temperature resistant silicone gel was prepared according to the method of Example 7, with the following changes:

[0124] The invention also contains 1 part of a co-solvent, which is the same as the co-solvent in Example 5.

[0125] Example 10

[0126] A one-component adhesive low-temperature resistant silicone gel was prepared according to the method of Example 8, with the following changes:

[0127] The invention also contains 1 part of a co-solvent, which is the same as the co-solvent in Example 5.

[0128] Test Example 1

[0129] In order to investigate the low temperature resistance of the one-component adhesive low temperature resistant silicone gel in the above embodiment, the one-component adhesive low temperature resistant silicone gel in the above embodiment was poured into a 2cm×2cm×2cm mold, cured in a 65°C oven for 1 hour, cooled to room temperature and placed in a -70°C low temperature box for 24 hours. The relevant test results are shown in Table 1 below.

[0130] The low temperature resistance test is carried out in accordance with GB / T 2423.1-2008 Environmental testing for electrical and electronic products;

[0131] Cone penetration is tested according to GB / T 269-2023 Cone penetration test method for lubricating grease and petroleum grease;

[0132] The room temperature storage time test adopts the dual temperature test method, and the samples are placed in a constant temperature incubator at 37°C, and the indicators are tested according to the predetermined test frequency. Under 37°C conditions, the test is conducted once a month for the first four months, once every half a month in the fifth month, and once a week from the sixth month until the sample fails. By calculating the effect of temperature on the shelf life, the Q10 value (chemical reaction rate increases by 2 times for every 10°C increase in temperature) is used to estimate the shelf life at different temperatures.

[0133] Table 1. Physical properties test results:

[0134]

[0135]

[0136] From the results in Table 1, it can be seen that the low-temperature resistance of this silicone gel increases with the increase of the phenyl molar content in the system from 10% to 30%, the refractive index becomes larger and larger, and the low-temperature resistance gradually deteriorates. In Examples 1 and 2, when the phenyl molar content in the phenyl vinyl silicone oil and the side hydrogen-containing phenyl silicone oil is 10% and 15%, the low-temperature resistance is excellent and the elasticity can still be maintained at -70°C. However, in Examples 3 and 4, when the phenyl molar content in the phenyl vinyl silicone oil and the side hydrogen-containing phenyl silicone oil is increased to 20% and 30%, the low-temperature resistance of the silicone gel deteriorates and the elasticity is poor at -70°C.

[0137] In addition, the greater the ratio of the total amount of terminal hydrogen silicone oil and side hydrogen phenyl silicone oil to the amount of phenyl vinyl silicone oil (Si-H / Si-Vi), the greater the crosslinking degree, and the smaller the cone penetration of the corresponding silicone gel. The room temperature storage time of this single-component silicone gel is related to the amount of catalyst used in the system.

[0138] Test Example 2

[0139] In order to investigate the performance of the one-component adhesive low-temperature resistant silicone gel in the above embodiment, the one-component adhesive low-temperature resistant silicone gel in the above embodiment was poured between the display screen and the touch screen, and cured in a 65°C oven for 1 hour. Then, the power was turned on normally and the display screen was observed. No bubbles were generated after the silicone gel was cured. The relevant test results are shown in Table 2 below.

[0140] Table 2, performance test results:

[0141]

[0142] From the results in Table 2, it can be seen that the greater the proportion of the coupling agent in the system, the better the corresponding bonding performance. On the contrary, if the proportion of the coupling agent is too small, it cannot be well bonded. By controlling the amount of the coupling agent, the silicone gel of the present invention can achieve primer-free bonding between display screens.

[0143] Test Example 3

[0144] In order to investigate the effect of the co-solvent on the transmittance of the one-component adhesive fluorosilicone gel in Examples 5, 6, 9 and 10, the transmittance of the one-component adhesive fluorosilicone gel in Examples 3 to 10 was tested. The fluorosilicone gel was cured into a 2 cm × 2 cm × 2 mm sheet in a mold, and the transmittance was tested according to the method for using a UV-visible spectrophotometer. The relevant test results are shown in Table 3.

[0145] Table 3. Transmittance test results

[0146]

[0147] From the results in Table 3, it can be seen that the addition of a cosolvent can effectively improve the compatibility of the substances in the system, thereby significantly improving the transmittance of the phenyl silicone gel after curing. The molar contents of phenyl in the phenyl vinyl silicone oil and the side hydrogen-containing phenyl silicone oil in the silicone gels of Examples 7 and 8 are 10% and 15%, respectively, and the molar contents of phenyl in the phenyl vinyl silicone oil and the side hydrogen-containing phenyl silicone oil in Examples 3 and 4 are 20% and 30%, respectively. The higher the phenyl content, the worse the compatibility between the components, which is manifested as slight turbidity in visual observation, and the transmittance will decrease. Therefore, compared with Examples 7 and 8, the transmittance of the silicone gels of Examples 3 and 4, in which no cosolvent is added, is lower.

[0148] In the description of the present application, it should be noted that the terms "upper", "lower", "inside", "outside", "front", "back", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships in the working state of the present application. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on the present application.

[0149] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "install", "connect" and "connect" should be understood in a broad sense. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0150] The present application has been described above in conjunction with preferred embodiments, but these embodiments are only exemplary and serve only as an illustration. On this basis, various replacements and improvements may be made to the present application, all of which fall within the scope of protection of the present application.

Claims

1. A one-component adhesive low-temperature resistant silicone gel, characterized in that: The following components are included by mass:

2. The one-component adhesive low-temperature resistant silicone gel according to claim 1, characterized in that: It also contains 1 to 2 parts of a co-solvent, the structural formula of which is as follows: Among them, n is 2 to 6.

3. The one-component adhesive low-temperature resistant silicone gel according to claim 1, characterized in that: The phenyl vinyl silicone oil is one or more selected from phenyl vinyl silicone oils having a vinyl content of 0.0175 to 0.05 mol / 100 g and a phenyl molar content of 10 to 30%; Preferably, the molar content of phenyl groups in the phenyl vinyl silicone oil is 10 to 15%.

4. The one-component adhesive low-temperature resistant silicone gel according to claim 1, characterized in that: The terminal hydrogen-containing silicone oil is one or more selected from terminal hydrogen-containing silicone oils with an active hydrogen mass fraction of 0.06 to 0.08%.

5. The one-component adhesive low-temperature resistant silicone gel according to claim 1, characterized in that: The mass fraction of active hydrogen in the side hydrogen-containing phenyl silicone oil is 0.01-0.1%, the molar content of phenyl is 10-30%, and the molar content of phenyl is preferably 10-15%.

6. The one-component adhesive low-temperature resistant silicone gel according to claim 1, characterized in that: The catalyst is a single-component platinum catalyst.

7. The one-component adhesive low-temperature resistant silicone gel according to claim 6, characterized in that: The mass of the catalyst is 2000-5000ppm of the mass of phenyl vinyl silicone oil.

8. The one-component adhesive low-temperature resistant silicone gel according to claim 1, characterized in that: The coupling agent is phenyl trimethoxy silicone oil, and the weight proportion of the coupling agent is 3 to 4 parts.

9. A method for preparing a one-component adhesive low-temperature resistant silicone gel, characterized in that: include: The following components in parts by mass are mixed and degassed to obtain a single-component adhesive low-temperature resistant silicone gel:

10. An application of a one-component adhesive low-temperature resistant silicone gel, characterized in that: The one-component adhesive low-temperature resistant silicone gel according to any one of claims 1 to 8 is poured between the touch screen and the display screen, and then cured.

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