Vinyl silicon resin as well as preparation method and application thereof

Abstract

The invention relates to vinyl silicone resin and a preparation method and application thereof, and belongs to the technical field of high-molecular compound preparation, the preparation method comprises the following steps: (1) mixing phenyl siloxane and a vinyl end-capping reagent to obtain a reaction substrate; (2) adding an aqueous solution of a strong acid catalyst into the reaction substrate obtained in the step (1), carrying out a reflux reaction to obtain a vinyl silicone resin hydrolysis crude product, and removing low-boiling-point substances to obtain a vinyl silicone resin precursor; and (3) reacting the vinyl silicone resin precursor obtained in the step (2) in the presence of a base catalyst in a reactor with a reflux water distribution device to obtain the vinyl silicone resin. According to the method, a strong acid catalyst-water co-feeding method is adopted, so that the hydrolytic activity and the temperature rise are controllable, the metering accuracy of the catalyst and the process safety are improved, and the obtained vinyl silicone resin has the advantages of wide molecular weight distribution, high light transmittance and the like.

Description

Technical Field

[0001] The invention relates to the technical field of polymer compound preparation, and in particular to a vinyl silicone resin and a preparation method and application thereof. Background Art

[0002] As a new generation of semiconductor solid-state light-emitting devices, light-emitting diodes (LEDs) are widely used in various lighting and display fields due to their high luminous efficiency and long service life. With the continuous improvement of the requirements for lighting brightness and luminous flux, LEDs are gradually developing towards high power density and multi-chip integration. They generate a lot of heat in the electro-optical conversion process, causing the device temperature to rise rapidly, seriously affecting the luminous performance and long-term reliability of high-power LED devices. Chip packaging materials, as key supporting and protective materials, directly affect the reliability, luminous performance and service life of LEDs. Therefore, in the field of LED lighting, packaging materials with high transmittance, high refractive index, excellent mechanical properties and high aging resistance are urgently needed.

[0003] As the main component of LED packaging materials, vinyl silicone resin directly affects the refractive index, hardness, light decay and crack resistance of the cured silicone. The synthesis process of vinyl silicone resin is complicated, and the more mature process mainly includes two steps: 1. Hydrolysis of siloxane and vinyl end-capping agent under acid catalysis; 2. Subsequent dehydration condensation under base catalysis to obtain vinyl silicone resin product.

[0004] For example, CN103012798A discloses a method for preparing a methylphenyl vinyl silicone resin, which comprises the following steps: firstly, an organic solvent, deionized water and a strong acid are mixed and stirred, and then a mixture consisting of a difunctional alkoxysilane, a trifunctional alkoxysilane, a monofunctional alkoxysilane and a tetraethoxysilane is added dropwise for hydrolysis reaction, and then the temperature is raised and refluxed to obtain a mixed solution; then the mixed solution is allowed to stand and cool to room temperature, and then an organic layer is separated, and the organic layer is washed with deionized water to neutrality, and then an alkaline catalyst is added to the organic layer, and the temperature is raised and refluxed for a period of time to obtain an azeotropic reflux liquid; the azeotropic reflux liquid is cooled to below 50°C, and then a solid acidic neutralizer is added to stir and neutralize, filter, and vacuum purify. The process is easy to control, has low labor intensity, low toxicity of the entire process, a wide source of monomers, low cost, and the obtained methylphenyl vinyl silicone resin has stable storage performance.

[0005] However, during the acid-catalyzed hydrolysis process, strong acid catalysts are often added at once. Strong acid catalysts have strong water absorption and are easy to volatilize, which is not conducive to the accurate measurement of the catalyst and will cause certain safety hazards to operators. In addition, when the strong acid catalyst is added to the phenylsiloxane and vinyl double-capped substrates at one time, the initial hydrolysis activity of adding pure water is very high, and the reaction process is difficult to control, which can easily lead to high reaction temperatures and imbalance of product structure, and then lead to poor stability of vinyl silicone resin production batches.

[0006] In summary, developing a method for preparing a vinyl silicone resin with controllable hydrolysis activity and temperature rise, which can obtain a wide molecular weight distribution, high transmittance and high refractive index, has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a vinyl silicone resin and a preparation method and application thereof. Through a specific feeding method, the hydrolysis activity and temperature rise are controllable, thereby improving the catalyst metering accuracy and process safety. The obtained vinyl silicone resin has the advantages of wide molecular weight distribution and high light transmittance, and can meet the application needs in the field of LED high-refractive packaging silicone and LED silicone solid crystal glue.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a method for preparing a vinyl silicone resin, the preparation method comprising the following steps:

[0010] (1) mixing phenylsiloxane and a vinyl end-capping agent to obtain a reaction substrate;

[0011] (2) adding an aqueous solution of a strong acid catalyst to the reaction substrate obtained in step (1), performing a reflux reaction, obtaining a crude hydrolysis product of a vinyl silicone resin, and removing low-boiling substances to obtain a vinyl silicone resin precursor;

[0012] (3) reacting the vinyl silicone resin precursor obtained in step (2) in the presence of an alkali catalyst in a reactor equipped with a reflux water separation device to obtain the vinyl silicone resin.

[0013] In the preparation method provided by the present invention, a strong acid catalyst-water co-feeding method is used, so that the hydrolysis activity and the temperature rise are controllable, the catalyst metering accuracy and process safety are improved, and the obtained vinyl silicone resin has the advantages of wide molecular weight distribution and high light transmittance; using phenylsiloxane as a preparation raw material is conducive to improving the refractive index of the obtained silicone resin; in addition, in the preparation method provided by the present invention, by removing low-boiling substances, the introduction of vinyl into the silicone resin main chain can be promoted, and it is conducive to the separation of water and toluene in the subsequent water separation process. If the low-boiling substances are not removed in time, the low-boiling substances (such as methanol) will be dissolved in water and toluene at the same time, resulting in an unclear water separation interface and increasing the water separation process time; reacting with an alkali catalyst in a reactor with a reflux water separation device, removing water or alcohols in time, is conducive to promoting dehydration condensation to finally form a silicone resin body structure, and the obtained resin has high transparency and excellent anti-cracking performance. From the perspective of reaction engineering, the preparation method provided by the present invention includes a process of continuous accumulation of the concentration of a strong acid catalyst, which broadens the molecular weight distribution of the vinyl silicone resin, increases the ratio of the amorphous region / crystalline region of the polymer, and improves the processing performance and light transmittance performance of the silicone resin.

[0014] Preferably, the raw materials for preparing the vinyl silicone resin include, by weight: 50-70 parts of phenyl siloxane (for example, 52, 55, 58, 60, 62, 65 or 68, etc.), 5-15 parts of vinyl end-capping agent (for example, 6, 8, 10, 12 or 14, etc.), 0.05-0.6 parts of strong acid catalyst (for example, 0.08 parts, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts or 0.5 parts, etc.), and 0.2-0.6 parts of base catalyst (for example, 0.25 parts, 0.3 parts, 0.35 parts, 0.4 parts, 0.45 parts, 0.5 parts or 0.55 parts, etc.).

[0015] Preferably, the phenylsiloxane includes any one of phenyltrialkoxysilane, phenyldialkoxysilane or diphenyldialkoxysilane, or a combination of at least two thereof.

[0016] Preferably, the phenylsiloxane includes any one of phenyltrimethoxysilane, diphenyldimethoxysilane, methylphenyldimethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, methylphenyldiethoxysilane, dimethylphenyldimethoxysilane or dimethylphenyldiethoxysilane, or a combination of at least two thereof.

[0017] In the present invention, the phenylsiloxane may be phenyltrimethoxysilane SICO-P13 (Shandong Sike), diphenyldimethoxysilane SICO-P212 (Shandong Sike), etc., which are well known to those skilled in the art.

[0018] Preferably, the phenylsiloxane comprises a combination of phenyltrialkoxysilane and diphenyldialkoxysilane.

[0019] As a preferred technical solution of the present invention, the use of phenyltrialkoxysilane with many cross-linking sites is beneficial to the preparation of silicone resin with a three-dimensional structure and improves the hardness of organic silicone; the use of diphenyldialkoxysilane can not only act as a chain extender to improve the processing rheological properties, but also increase the refractive index of silicone resin; phenyltrialkoxysilane and diphenyldialkoxysilane synergistically enhance the performance and obtain vinyl silicone resin with better application performance.

[0020] Preferably, the vinyl end-capping agent includes a vinyl single end-cap and / or a vinyl double end-cap.

[0021] Preferably, the mixing temperature in step (1) is 30-80°C, for example, 35°C, 40, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C or 75°C, as well as specific values ​​between the above-mentioned points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range.

[0022] Preferably, the mixing time in step (1) is 0.1-1 h, for example, 0.2 h, 0.3 h, 0.4 h, 0.5 h, 0.6 h, 0.7 h, 0.8 h or 0.9 h, as well as specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range.

[0023] Preferably, the strong acid catalyst comprises any one of hydrochloric acid, sulfuric acid, acetic acid or trifluoromethanesulfonic acid, or a combination of at least two thereof.

[0024] In the present invention, the strong acid catalyst may be trifluoromethanesulfonic acid (Hangzhou Bangyi Chemical), hydrochloric acid (Shanghai Maclean), acetic acid (Aladdin), etc., which are well known to those skilled in the art.

[0025] Preferably, the mass concentration of the strong acid catalyst in the aqueous solution of the strong acid catalyst is 0.1-5%, for example, it can be 0.2%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.5%, 3% or 4%, and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range, and it is further preferably 0.1-2%.

[0026] Preferably, the addition rate of the aqueous solution of the strong acid catalyst is 1-5 drops / s, for example, it can be 1.5 drops / s, 2 drops / s, 2.5 drops / s, 3 drops / s, 3.5 drops / s, 4 drops / s or 4.5 drops / s, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0027] In the present invention, the aqueous solution of the strong acid catalyst is added dropwise into the reaction substrate, and the concentration is prepared as any one of single concentration, multiple concentrations, pure water, or a combination of at least two of them.

[0028] In the present invention, the aqueous solution of the strong acid catalyst is added dropwise into the reaction substrate, and the optional concentration preparation combination (taking 1 part by weight of the strong acid catalyst and 240 parts by weight of water as an example, the weight of the strong acid catalyst is adjustable) includes: a solution of 1 part by weight of the strong acid catalyst and 240 parts by weight of water is added dropwise at a uniform speed of 1 drop / s; a solution of 1 part by weight of the strong acid catalyst and 240 parts by weight of water is first added dropwise at a uniform speed of 1 drop / s, and then added dropwise at 2-3 drops / s after half of the addition is completed; a solution of 1 part by weight of the strong acid catalyst and 140 parts by weight of water is added dropwise at a uniform speed of 1 drop / s, and then 100 parts by weight of pure water is added dropwise at 2 drops / s after the addition is completed; a solution of 0.4 parts by weight of the strong acid catalyst and 60 parts by weight of water is added dropwise at a uniform speed of 1 drop / s, and then 0.6 parts by weight of the strong acid catalyst and 80 parts by weight of water is added dropwise at 1.5 drops / s after the addition is completed, and finally 100 parts by weight of pure water is added dropwise at 2 drops / s.

[0029] Preferably, the temperature of the reflux reaction in step (2) is 40-80°C, for example, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C or 75°C, as well as specific values ​​between the above-mentioned values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific values ​​included in the range.

[0030] Preferably, the reflux reaction time in step (2) is 0.5-4.5 h, for example, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h or 4 h, as well as specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range.

[0031] Preferably, the low boiling substances include water and / or alcohol compounds.

[0032] Preferably, the operation of removing low boiling substances comprises evaporation.

[0033] Preferably, the evaporation temperature is 85-108°C, for example, it can be 88°C, 90°C, 92°C, 95°C, 98°C, 100°C, 102°C or 105°C, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0034] Preferably, the evaporation time is 2-4 h, for example, it can be 2.2 h, 2.5 h, 2.8 h, 3 h, 3.2 h, 3.5 h or 3.8 h, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0035] Preferably, the base catalyst includes any one of KOH, NaOH, tetramethylammonium hydroxide, tetramethylammonium hydroxide pentahydrate or LiOH, or a combination of at least two thereof.

[0036] Preferably, the reaction in step (3) is carried out in the presence of a solvent.

[0037] Preferably, in parts by weight, the base catalyst in step (3) is 0.2-0.6 parts, and the solvent is 20-80 parts, for example, 30 parts, 40 parts, 50 parts, 60 parts or 70 parts, as well as specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range.

[0038] Preferably, the solvent includes any one of toluene, xylene or acetone, or a combination of at least two of them.

[0039] In the present invention, the solvent may be toluene (Hangzhou Bangyi Chemical), xylene (Hangzhou Bangyi Chemical), acetone (Hangzhou Bangyi Chemical), etc., which are well known to those skilled in the art.

[0040] Preferably, the reaction temperature in step (3) is 90-125°C, for example, 95°C, 100°C, 105°C, 110°C, 115°C or 120°C, as well as specific values ​​between the above-mentioned values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific values ​​included in the range.

[0041] Preferably, the reaction time in step (3) is 4-12 h, for example, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h or 11 h, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention no longer exhaustively lists the specific values ​​included in the range.

[0042] Preferably, the base catalyst is neutralized or removed after the reaction in step (3) to obtain the vinyl silicone resin.

[0043] Preferably, the neutralization is performed in the presence of a neutralizing agent.

[0044] Preferably, the neutralizing agent comprises any one of ammonium bicarbonate, sodium bicarbonate or acetic acid, or a combination of at least two thereof.

[0045] Preferably, the weight proportion of the neutralizing agent is 0.3-0.8 parts, for example, it can be 0.35 parts, 0.4 parts, 0.5 parts, 0.6 parts or 0.7 parts, as well as specific points between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range.

[0046] Preferably, the neutralization or removal of the alkali catalyst is followed by water washing and filtering.

[0047] Preferably, in parts by weight, the preparation method comprises the following steps:

[0048] (1) Mixing 50-70 parts of phenyl siloxane and 5-15 parts of vinyl end-capping agent at 30-80° C. for 0.1-1 h to obtain a reaction substrate;

[0049] (2) adding a 0.1-2% mass concentration of a strong acid catalyst aqueous solution to the reaction substrate obtained in step (1) at a rate of 1-5 drops / s, reacting under reflux at 40-80° C. for 0.5-4.5 h to obtain a vinyl silicone resin hydrolysis crude product, and evaporating at 85-108° C. for 2-4 h to remove low-boiling substances to obtain a vinyl silicone resin precursor;

[0050] Wherein, the weight portion of the strong acid catalyst is 0.05-0.6 parts;

[0051] (3) reacting the vinyl silicone resin precursor obtained in step (2) with 0.2-0.6 parts of an alkali catalyst and 20-80 parts of a solvent at 90-125° C. for 4-12 h in a reactor equipped with a reflux water separation device, neutralizing or removing the alkali catalyst with 0.3-0.8 parts of a neutralizing agent, washing with water, and filtering to obtain the vinyl silicone resin.

[0052] In a second aspect, the present invention provides a vinyl silicone resin, which is prepared by the preparation method described in the first aspect.

[0053] Preferably, the light transmittance of the vinyl silicone resin is ≥ 97%, for example, it may be 97.2%, 97.5%, 97.8%, 98%, 98.2%, 98.5%, 98.8%, 99%, 99.2%, 99.5% or 99.8%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0054] Preferably, the refractive index of the vinyl silicone resin is ≥1.5, for example, it may be 1.52, 1.55, 1.58, 1.6, 1.62, 1.65, 1.68, 1.7, 1.75 or 1.8, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0055] Preferably, the molecular weight distribution of the vinyl silicone resin is ≥1.35, for example, it can be 1.38, 1.4, 1.42, 1.45, 1.48, 1.5, 1.55 or 1.6, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0056] Preferably, the weight average molecular weight of the vinyl silicone resin is 800-1500 g / mol, for example, it can be 900 g / mol, 1000 g / mol, 1100 g / mol, 1200 g / mol, 1300 g / mol or 1400 g / mol, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0057] In a third aspect, the present invention provides a use of the vinyl silicone resin as described in the second aspect in LED chip packaging.

[0058] Preferably, the application includes LED high-fold packaging silicone or LED silicone bonding glue.

[0059] Compared with the prior art, the present invention has at least the following beneficial effects:

[0060] The invention adopts a strong acid catalyst-water co-feeding method to make the hydrolysis activity and temperature rise controllable, thereby improving the catalyst metering accuracy and process safety. The process is simple, the conditions are mild and easy to control, and the obtained vinyl silicone resin has a refractive index of ≥1.5, a transmittance of ≥97%, and a molecular weight distribution of ≥1.35. It has the advantages of wide molecular weight distribution, high refractive index and high transmittance, and can meet the application requirements in chip packaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 is the GPC curve of the vinyl silicone resin obtained in Example 2;

[0062] Figure 2 This is the GPC curve of the vinyl silicone resin obtained in Comparative Example 1. DETAILED DESCRIPTION

[0063] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementation methods. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0064] In the following specific implementations of the present invention, the materials involved are shown in Table 1:

[0065] Table 1

[0066]

[0067] Example 1

[0068] A method for preparing a vinyl silicone resin, the method comprising the following steps:

[0069] (1) 186.04 g of SICO-P13, 22.1 g of SICO-P212 and 28.15 g of vinyl double-end capped polyol were added into a stirred reactor and heated and stirred at 50 °C for 0.15 h to obtain a reaction substrate;

[0070] (2) adding an aqueous solution prepared by 0.4 g of a strong acid catalyst and 66.3 g of deionized water to the reaction substrate at a uniform rate of 2 drops / s. After all the addition was completed, the mixture was refluxed at 78°C for 3.5 h to obtain a crude hydrolysis product of vinyl silicone resin. The mixture was heated to 92°C and evaporated for 2.5 h to remove water and alcohol fractions to obtain a vinyl silicone resin precursor.

[0071] (3) The vinyl silicone resin precursor was cooled to room temperature, 230 g of toluene and 1.5 g of an alkali catalyst were added, and the mixture was refluxed at 121° C. for 8 h to obtain a vinyl silicone resin solution. The vinyl silicone resin solution was neutralized with a neutralizing agent, sodium bicarbonate, and then washed with water for multiple times until it was neutral. The solution was filtered to remove the solvent, and the vinyl silicone resin was obtained.

[0072] Example 2

[0073] A method for preparing a vinyl silicone resin, the method comprising the following steps:

[0074] (1) Add 66.7 g of SICO-P13 and 9.86 g of vinyl double-capped reactor into a stirred reactor, heat and stir at 40 °C for 0.2 h to obtain a reaction substrate;

[0075] (2) An aqueous solution prepared by adding 0.12 g of a strong acid catalyst and 21.8 g of deionized water was first added dropwise at a uniform rate of 1 drop / s, and then added dropwise to the reaction substrate at a rate of 2.5 drops / s after half of the addition was completed. After all the addition was completed, the mixture was refluxed at 78°C for 4.5 h to obtain a crude hydrolysis product of vinyl silicone resin, which was then heated to 105°C and evaporated for 3.0 h to remove water and alcohol fractions to obtain a vinyl silicone resin precursor;

[0076] (3) The vinyl silicone resin precursor was cooled to room temperature, 42 g of xylene and 0.50 g of an alkali catalyst were added, and the mixture was refluxed at a high temperature of 118° C. for 6 h to obtain a vinyl silicone resin solution. The vinyl silicone resin solution was neutralized with a neutralizing agent, ammonium bicarbonate, and then washed with water for multiple times until it was neutral. The solution was filtered to remove the solvent, and the vinyl silicone resin was obtained.

[0077] Example 3

[0078] A method for preparing a vinyl silicone resin, the method comprising the following steps:

[0079] (1) Add 66.7 g of SICO-P13 and 9.86 g of vinyl double-capped reactor into a stirred reactor, and heat and stir at 40 °C to obtain a reaction substrate;

[0080] (2) First, a solution prepared by adding 0.12 g of a strong acid catalyst and 11.8 g of deionized water was added dropwise at a uniform rate of 1 drop / s. After the addition was completed, 10.0 g of deionized water was added dropwise to the reaction substrate at a rate of 2.5 drops / s. After all the addition was completed, the mixture was refluxed at 78°C for 4.5 hours to obtain a crude hydrolysis product of vinyl silicone resin. The mixture was heated to 105°C and evaporated for 3.0 hours to remove water and alcohol fractions to obtain a vinyl silicone resin precursor.

[0081] (3) Cooling the vinyl silicone resin precursor to room temperature, adding 42 g of xylene and 0.50 g of an alkali catalyst, and refluxing at a high temperature of 118° C. for 6 h to separate water, thereby obtaining a vinyl silicone resin solution. After neutralizing the vinyl silicone resin solution with acetic acid as a neutralizing agent, the solution was washed with water for multiple times until it was neutral, and filtered to remove the solvent to obtain the vinyl silicone resin.

[0082] Example 4

[0083] A method for preparing a vinyl silicone resin, the method comprising the following steps:

[0084] (1) Add 66.7 g of SICO-P13 and 9.86 g of vinyl double-capped reactor into a stirred reactor, and heat and stir at 40 °C to obtain a reaction substrate;

[0085] (2) First, a solution prepared by adding 0.05 g of a strong acid catalyst and 6.1 g of deionized water was added dropwise at a uniform rate of 1 drop / s, and then a solution prepared by adding 0.07 g of a strong acid catalyst and 8.3 g of deionized water was added dropwise at a rate of 1.5 drops / s. Finally, 7.4 g of deionized water was added dropwise to the reaction substrate at a rate of 2 drops / s. After all the additions were completed, the mixture was refluxed at 78°C for 4.5 hours to obtain a crude product of vinyl silicone resin hydrolysis. The mixture was heated to 105°C and evaporated for 4.0 hours to remove water and alcohol fractions to obtain a vinyl silicone resin precursor.

[0086] (3) The vinyl silicone resin precursor was cooled to room temperature, 42 g of xylene and 0.50 g of an alkali catalyst were added, and the mixture was refluxed at a high temperature of 118° C. for 6 h to obtain a vinyl silicone resin solution. The vinyl silicone resin solution was neutralized with a neutralizing agent, ammonium bicarbonate, and then washed with water for multiple times until it was neutral. The solution was filtered to remove the solvent, and the vinyl silicone resin was obtained.

[0087] Example 5

[0088] The difference between Example 5 and Example 2 is that only in step (2), the aqueous solution is first added at a uniform speed of 3 drops / s, and after half of the addition is completed, it is added to the reaction substrate at a uniform speed of 6 drops / s, and the rest remains the same.

[0089] Comparative Example 1

[0090] A method for preparing a vinyl silicone resin, the method comprising the following steps:

[0091] (1) 66.7 g of SICO-P13, 0.12 g of a strong acid catalyst and 9.86 g of a vinyl double-end reactor were added to a stirred reactor and heated and stirred at 40 °C to obtain a reaction substrate;

[0092] (2) 21.8 g of deionized water was added dropwise at a uniform rate of 1 drop / s. After half of the addition was completed, the mixture was added dropwise to the reaction substrate at a rate of 2.5 drops / s. After all the addition was completed, the mixture was refluxed at 78° C. for 4.5 h to obtain a crude hydrolysis product of vinyl silicone resin. The subsequent steps were the same as in Example 2 to obtain the vinyl silicone resin.

[0093] Comparative Example 2

[0094] A method for preparing a vinyl silicone resin, the method comprising the following steps:

[0095] (1) 66.7 g of SICO-P13, 0.12 g of a strong acid catalyst and 9.86 g of a vinyl double-end reactor were added to a stirred reactor, and heated and stirred at 40°C to obtain a reaction substrate;

[0096] (2) 21.8 g of deionized water was added dropwise to the reaction substrate at a uniform rate of 1 drop / s. After all the addition was completed, the reaction was refluxed at 78° C. for 4.5 h to obtain a crude hydrolysis product of vinyl silicone resin. The subsequent steps were the same as in Example 2 to obtain the vinyl silicone resin.

[0097] Comparative Example 3

[0098] A method for preparing a vinyl silicone resin, the method comprising the following steps:

[0099] (1) adding 21.8 g of deionized water and 0.12 g of a strong acid catalyst into a stirred reactor, heating and stirring at 40° C. to obtain a first mixture;

[0100] (2) 66.7 g of SICO-P13 and 9.86 g of vinyl double-capped resin were added dropwise to the first mixture at a uniform rate of 2 drops / s. After all the addition was completed, the mixture was refluxed at 78° C. for 4.5 h to obtain a crude hydrolysis product of vinyl silicone resin. The subsequent steps were consistent with Example 2 to obtain the vinyl silicone resin.

[0101] Comparative Example 4

[0102] A method for preparing a vinyl silicone resin, the method differing from Example 2 only in that step (3) is not carried out in a reactor with a reflux water separation device, but is carried out in a reflux device, i.e., only reflux is carried out without water separation.

[0103] The above vinyl silicone resin was tested as follows:

[0104] 1) Hydrolysis temperature rise ΔT

[0105] The initial temperature of the reaction substrate before water is added in step (1) is recorded as T0, the highest temperature during the process of adding the aqueous solution of the strong acid catalyst in step (2) is recorded as T1, and the hydrolysis temperature rise ΔT=T1-T0.

[0106] 2) Atomization of strong acid catalyst

[0107] When removing strong acid catalysts, observe whether irritating white acid mist appears.

[0108] 3) Determination of weight average molecular weight and molecular weight distribution

[0109] The molecular weight and distribution of the samples were determined using a PL GPC 220 high temperature gel chromatography (Polymer Laboratories, Church Stretton, UK) equipped with a differential refractive index detector. The solvent used was 1,2,4-trichlorobenzene (TCB) at a flow rate of 1.0 mL / min.

[0110] 4) Optical properties

[0111] The above vinyl silicone resin was prepared into a glue according to the following weight parts: 63 parts of the vinyl silicone resin obtained in the examples or comparative examples, 17.9 parts of phenyl hydrogenated silicone oil IOTA 232 (Anhui Aiyota Silicone Oil), 2 parts of phenyl hydrogenated silicone oil IOTA 235 (Anhui Aiyota Silicone Oil), 15.2 parts of phenyl vinyl silicone oil IOTA 252-5000vi (Anhui Aiyota Silicone Oil), 1 part of tackifier Z-1501 (Jiangxi Lutai Technology Co., Ltd.), 0.5 parts of 0.05 wt% Karstedt Pt catalyst (Heraeus), and 0.4 parts of 1-ethynyl-1-cyclohexanol;

[0112] After preparation, it was cured in an oven at 160°C for 2 h to obtain the cured organic silica gel for subsequent refractive index and transmittance tests.

[0113] Refractive index: Tested in accordance with GB / T 614.

[0114] Light transmittance: The UV-2601 ultraviolet-visible spectrophotometer produced by Beijing Beifen Rayleigh Analytical Instrument Co., Ltd. was used to prepare the silicone into 2 mm thick strips, and the light transmittance of the cured silicone at a wavelength of 450 nm was tested.

[0115] The test results are summarized in Table 2.

[0116] Table 2

[0117]

[0118] It can be seen from the test results that the present invention adopts a strong acid catalyst-water co-feeding method to make the hydrolysis activity and temperature rise controllable, thereby improving the catalyst metering accuracy and process safety. The preparation method is simple and easy to control, and the conditions are mild. The obtained vinyl silicone resin has a weight-average molecular weight between 1017 and 1301 g / mol, a refractive index of ≥1.53, a transmittance of ≥97.8%, and a molecular weight distribution of ≥1.36, and has the advantages of wide molecular weight distribution, and high refractive index and transmittance.

[0119] By comparing Example 1 with Example 2, it can be found that the use of a combination of specific phenyl siloxanes increases the phenyl content and refractive index of the vinyl silicone resin, and the resulting resin has a wider molecular weight distribution and improved light transmittance.

[0120] By comparing Example 5, Example 3 and Example 2, it can be found that the concentration of the strong acid catalyst accumulates faster, resulting in an increase in the hydrolysis temperature rise ΔT, a decrease in the weight average molecular weight and the molecular weight distribution, and a deterioration in the transmittance of the formulated adhesive.

[0121] By comparing Comparative Examples 1 and 2 with Examples 1-4, it can be found that when the strong acid catalyst-water co-feeding method is not adopted, the hydrolysis temperature increases, the strong acid catalyst is atomized, the catalyst metering accuracy and process safety deteriorate, and the molecular weight distribution of the obtained phenyl vinyl silicone resin is narrow (such as Figure 1 , Figure 2 As shown in the figure), the ratio of amorphous region to crystalline region of the polymer is reduced and the light transmittance performance of silicone resin is poor.

[0122] By comparing Comparative Example 3 and Example 2, it can be found that when the reaction substrate is added dropwise to the strong acid catalyst aqueous solution, the strong acid catalyst does not atomize, but the hydrolysis temperature rise ΔT is higher and the molecular weight of the obtained resin is larger, resulting in a significant decrease in the transmittance of the formulated adhesive.

[0123] By comparing Comparative Example 4 and Example 2, it can be found that the water is not separated in time during the catalyst reaction, which is not conducive to promoting the dehydration condensation to finally form a silicone resin body structure, resulting in an excessively high hydroxyl content of the silicone resin, milky turbidity, and affecting the transparency of the obtained vinyl silicone resin.

[0124] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a vinyl silicone resin, characterized in that: The preparation method comprises the following steps: (1) mixing phenylsiloxane and a vinyl end-capping agent to obtain a reaction substrate; (2) adding an aqueous solution of a strong acid catalyst to the reaction substrate obtained in step (1), performing a reflux reaction, obtaining a crude hydrolysis product of a vinyl silicone resin, and removing low-boiling substances to obtain a vinyl silicone resin precursor; (3) reacting the vinyl silicone resin precursor obtained in step (2) in the presence of an alkali catalyst in a reactor equipped with a reflux water separation device to obtain the vinyl silicone resin.

2. The preparation method according to claim 1, characterized in that: The raw materials for preparing the vinyl silicone resin include, by weight: 50-70 parts of phenyl siloxane, 5-15 parts of vinyl end-capping agent, 0.05-0.6 parts of strong acid catalyst, and 0.2-0.6 parts of base catalyst.

3. The preparation method according to claim 1, characterized in that: The phenylsiloxane comprises a combination of phenyltrialkoxysilane and diphenyldialkoxysilane; The vinyl end-capping agent includes a vinyl single end-capping agent and / or a vinyl double end-capping agent; The mixing temperature in step (1) is 30-80°C; The mixing time in step (1) is 0.1-1 h.

4. The preparation method according to claim 1, characterized in that: The strong acid catalyst includes any one of hydrochloric acid, sulfuric acid, acetic acid or trifluoromethanesulfonic acid or a combination of at least two thereof; The mass concentration of the strong acid catalyst in the aqueous solution of the strong acid catalyst is 0.1-5%; The addition rate of the aqueous solution of the strong acid catalyst is 1-5 drops / s; The temperature of the reflux reaction in step (2) is 40-80°C; The reflux reaction time in step (2) is 0.5-4.5 h.

5. The preparation method according to claim 1, characterized in that: The low boiling substances include water and / or alcohol compounds; The operation of removing low boiling substances includes evaporation; The evaporation temperature is 85-108°C; The evaporation time is 2-4 h.

6. The preparation method according to claim 1, characterized in that: The base catalyst includes any one of KOH, NaOH, tetramethylammonium hydroxide, tetramethylammonium hydroxide pentahydrate or LiOH, or a combination of at least two thereof; The reaction in step (3) is carried out in the presence of a solvent; In parts by weight, the base catalyst in step (3) is 0.2-0.6 parts, and the solvent is 20-80 parts; The solvent includes any one of toluene, xylene or acetone or a combination of at least two thereof; The reaction temperature in step (3) is 90-125°C; The reaction time in step (3) is 4-12 h.

7. The preparation method according to claim 1, characterized in that: After the reaction in step (3), the base catalyst is neutralized or removed to obtain the vinyl silicone resin; The neutralization is carried out in the presence of a neutralizing agent; The neutralizing agent includes any one of ammonium bicarbonate, sodium bicarbonate or acetic acid or a combination of at least two thereof; The weight portion of the neutralizing agent is 0.3-0.8 parts; After neutralization or removal of the alkali catalyst, washing and filtering are performed.

8. The preparation method according to claim 1, characterized in that: In parts by weight, the preparation method comprises the following steps: (1) Mixing 50-70 parts of phenyl siloxane and 5-15 parts of vinyl end-capping agent at 30-80° C. for 0.1-1 h to obtain a reaction substrate; (2) adding a 0.1-2% mass concentration of a strong acid catalyst aqueous solution to the reaction substrate obtained in step (1) at a rate of 1-5 drops / s, reacting under reflux at 40-80° C. for 0.5-4.5 h to obtain a vinyl silicone resin hydrolysis crude product, and evaporating at 85-108° C. for 2-4 h to remove low-boiling substances to obtain a vinyl silicone resin precursor; Wherein, the weight portion of the strong acid catalyst is 0.05-0.6 parts; (3) reacting the vinyl silicone resin precursor obtained in step (2) with 0.2-0.6 parts of an alkali catalyst and 20-80 parts of a solvent at 90-125° C. for 4-12 h in a reactor equipped with a reflux water separation device, neutralizing or removing the alkali catalyst with 0.3-0.8 parts of a neutralizing agent, washing with water, and filtering to obtain the vinyl silicone resin.

9. A vinyl silicone resin, characterized in that: The vinyl silicone resin is prepared by the preparation method according to any one of claims 1 to 8.

10. A use of the vinyl silicone resin as claimed in claim 9, characterized in that: The vinyl silicone resin is used for LED chip packaging.

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