阅读说明：本技术 一种可双固化聚硅氧烷及其制备方法和用途 (Dual-curable polysiloxane and preparation method and application thereof ) 是由 马伟 张聪颖 张雨 刘志锋 曹骏 封玲珑 高源� 杨继鹏 于 2019-08-30 设计创作，主要内容包括：本发明公开一种可双固化聚硅氧烷及其制备方法和用途。所述聚硅氧烷分子结构中含有丙烯酸酯类基团可以在紫外光照条件下快速交联固化,端基结构中含有湿气固化基团,因此该聚合物同时具备湿气固化和UV光固化的能力。本发明提供的合成路线可以避免丙烯酸酯的生成,硅羟基残余低于1％,同时降低了聚合物光固化所需的能量,提升了固化物耐湿热老化的能力。(The invention discloses a dual-curing polysiloxane, a preparation method and application thereof. The polysiloxane molecular structure contains acrylate groups which can be rapidly crosslinked and cured under the ultraviolet illumination condition, and the terminal group structure contains moisture curing groups, so that the polymer has the moisture curing and UV light curing capabilities. The synthetic route provided by the invention can avoid the generation of acrylic ester, the residue of silicon hydroxyl is lower than 1%, and meanwhile, the energy required by polymer photocuring is reduced, and the ability of a cured product to resist damp, heat and aging is improved.)

1. A dual curable polysiloxane having the formula:

wherein R is₁、R₂、R₃And R₆Independently of each other are R₄And R₅Independently of one another are-OCH₃、-OC₂H₅or-CH₂OCOCH₃Degree of polymerization n₁And n₂Independently of each other 10 to 1000, n₁And n₂Identical or different, preferably, n₁＝n₂＝50-200，n₃1-20, preferably 3-8.

2. A method for preparing the dual curable polysiloxane of claim 1, comprising the steps of:

a) under the condition of inert atmosphere and in the presence of a catalyst A, carrying out chain extension reaction on hydroxyl-terminated polysiloxane and dimethoxydichloropropylsilane, adding an end-capping reagent A for end-capping reaction after reacting for a certain time, and then removing low-boiling-point substances under reduced pressure;

(b) adding a polymerization inhibitor, a catalyst B and a blocking agent B into the product obtained in the step (a) to carry out salt-forming reaction, decompressing and removing low-boiling-point substances after the reaction is finished, and filtering to obtain the product.

3. The method according to claim 2, wherein the catalyst a in step (a) is one or more of acetic acid, hydrochloric acid, phosphoric acid and a phosphate ester, preferably dibutyl phosphate.

4. The process according to claim 2, wherein the blocking agent A in step (a) is one or more of chloropropyltrimethoxysilane, chloropropyltriethoxysilane and chloropropyltriacetoxysilane, preferably chloropropyltrimethoxysilane.

5. The method according to claim 2, wherein in step (a), the hydroxyl-terminated polysiloxane is added in an amount of 45 to 55 parts, the dimethoxydichloropropylsilane is added in an amount of 1 to 3 parts, preferably 1.5 to 2.5 parts, the blocking agent A is added in an amount of 3 to 5 parts, preferably 3.5 to 4.8 parts, and the catalyst A is added in an amount of 0.03 to 0.1 part, preferably 0.05 to 0.08 part.

6. The process of claim 2, wherein the catalyst B in step (B) is tetramethylammonium hydroxide and/or tetramethylammonium bromide, preferably tetramethylammonium hydroxide.

7. The method according to claim 2, wherein the blocking agent B of step (B) is sodium acrylate and/or sodium methacrylate, preferably sodium acrylate.

8. The method according to claim 2, wherein in the step (B), the addition amount of the blocking agent B is 1 to 3 parts, the addition amount of the catalyst B is 0.1 to 0.4 part, and the addition amount of the polymerization inhibitor is 0.0005 to 0.002 part; preferably, the addition amount of the blocking agent B is 1.5-2.5 parts, the addition amount of the catalyst B is 0.2-0.35 part, and the addition amount of the polymerization inhibitor is 0.001-0.0015 part.

9. Use of the dual curable polysiloxane according to claim 1 as a dual curable coating or adhesive.

Technical Field

The invention relates to a dual-curing polysiloxane and a preparation method and application thereof, belonging to the field of silicon materials.

Background

The unique molecular structure of the organic silicon enables the organic silicon to have the performances of inorganic materials and organic materials, has excellent characteristics of oxidation resistance, stability, weather resistance, flame retardancy, hydrophobicity, corrosion resistance, physiological inertia and the like, and is widely applied to the protection of electronic circuit boards and main parts.

The ultraviolet curing technology has the characteristics of fast curing, energy conservation, normal-temperature curing, less pollution, excellent performance and the like, and is a new-generation green chemical technology. The photosensitive groups are introduced to the polysiloxane molecular chain to form the light-curable polysiloxane, so that the curing efficiency is improved, the energy is saved, and the pollution to the environment is reduced. The application field and the product variety of the organic silicon material are greatly expanded by combining the organic silicon material with the light curing technology.

The disclosed technology for preparing the dual-curing type organosilicon material is to carry out end capping reaction on hydroxyl silicone oil by using an end capping agent containing acrylate groups, the acrylate groups used in the synthesis method can generate ester decomposition reaction under the catalysis of a catalyst in the synthesis process to cause the production of acrylate, and the acrylate has strong pungent smell and can generate great harm to human bodies and the environment. The high energy requirements for photocuring of the resulting product have LED to limitations in applications where LEDs are the light source.

CN102408569A discloses a dual-curable polysiloxane acrylate resin and a preparation method thereof, wherein dibutyltin dilaurate is used as a catalyst, toluene or n-hexane is used as a solvent, and an organic silicon polymer with dual-curing capability is prepared, but the photo-curing energy of the obtained product is higher.

CN105348536A discloses a method for preparing UV/moisture dual-curing polymer by using hydrogen without solventThe light curing energy is lower than 1000mJ/cm by using lithium oxide as a catalyst²The product of (2) a dual cure silicone polymer, but containing a significant amount of free methyl acrylate.

CN104193996A discloses a preparation method of dual-curing organosilicon glue, which takes organotin as a catalyst and obtains a dual-curing organosilicon polymer capable of improving bonding strength by dripping hydroxy silicone oil, but the light curing energy of the dual-curing organosilicon polymer can reach 8000-²。

There is therefore a need for a new preparation process which avoids the formation of acrylates and at the same time reduces the energy required for the polymerization to effect photocuring.

Disclosure of Invention

The invention provides a novel dual-curing polysiloxane and a preparation method thereof, wherein no acrylic ester is generated in the preparation process, the end capping rate of the obtained polymer is high, and the photocuring energy is low.

In order to solve the technical problems, the technical scheme of the invention is as follows:

a method for preparing a dual cure polysiloxane comprising the steps of:

(a) under the condition of inert atmosphere and in the presence of a catalyst A, carrying out chain extension reaction on hydroxyl-terminated polysiloxane and dimethoxydichloropropylsilane, adding an end-capping reagent A for end-capping reaction after reacting for a certain time, and then removing low-boiling-point substances under reduced pressure;

(b) adding a polymerization inhibitor, a catalyst B and a blocking agent B into the product obtained in the step (a) to carry out salt-forming reaction, decompressing and removing low-boiling-point substances after the reaction is finished, and filtering to obtain the product.

A dual curable polysiloxane having the formula:

wherein R is₁、R₂、R₃And R₆Independently of each other are R₄And R₅Independently of one another are-OCH₃、-OC₂H₅or-CH₂OCOCH₃Degree of polymerization n₁And n₂Independently of each other 10 to 1000, n₁And n₂Identical or different, preferably, n₁＝n₂＝50-200，n₃1-20, preferably 3-8.

The residue of silicon hydroxyl of the dual-curing polysiloxane is less than 1 percent, calculated based on the content of silicon hydroxyl in the raw material hydroxyl-terminated polysiloxane, free acrylate monomers are not contained, and the photocuring energy is less than 800mJ/cm²。

The catalyst A in the step (a) of the invention is one or more of acetic acid, hydrochloric acid, phosphoric acid and phosphate ester, preferably dibutyl phosphate.

The end capping agent A in the step (a) is one or more of chloropropyl trimethoxy silane, chloropropyl triethoxy silane and chloropropyl triacetoxy silane, preferably chloropropyl trimethoxy silane.

In the step (a), the addition amount of the hydroxyl-terminated polysiloxane is 45-55 parts, the addition amount of the dimethoxy dichloropropyl silane is 1-3 parts, the addition amount of the end-capping agent A is 3-5 parts, and the addition amount of the catalyst A is 0.03-0.1 part.

Preferably, in step (a) of the present invention, the amount of dimethoxydichloropropylsilane added is 1.5-2.5 parts, the amount of capping agent A added is 3.5-4.8 parts, and the amount of catalyst A added is 0.05-0.08 part.

The reaction of step (a) according to the present invention is carried out at 50-70 ℃.

The conditions for removing the low-boiling substances in the step (a) of the invention are 100 ℃ and 120 ℃, and 1-5mbar (absolute pressure).

The catalyst B in the step (B) of the present invention is tetramethylammonium hydroxide and/or tetramethylammonium bromide, preferably tetramethylammonium hydroxide;

the blocking agent B in the step (B) of the invention is sodium acrylate and/or sodium methacrylate, preferably sodium acrylate.

The polymerization inhibitor in step (b) of the present invention is one or more selected from commercially available polymerization inhibitors such as N, N-diethylhydroxylamine, 2, 6-di-tert-butyl-4-methylphenol (BHT), p-hydroxyanisole (MEHQ), phenothiazine, etc., and p-hydroxyphenol is preferred.

In the step (B), the addition amount of the blocking agent B is 1-3 parts, the addition amount of the catalyst B is 0.1-0.4 part, and the addition amount of the polymerization inhibitor is 0.0005-0.002 part.

Preferably, in step (B) of the present invention, the addition amount of blocking agent B is 1.5-2.5 parts, the addition amount of catalyst B is 0.2-0.35 part, and the addition amount of polymerization inhibitor is 0.001-0.0015 part.

The reaction of step (b) according to the present invention is carried out at 80-100 ℃.

The low-boiling-point substance removal operation conditions in step (b) of the present invention are 130 ℃ and 150 ℃, and 1-5mbar (absolute pressure).

The parts are calculated by mass.

The invention further provides the application of the UV/moisture dual-curing polysiloxane as a UV/moisture dual-curing polysiloxane coating or adhesive.

A dual curable polysiloxane coating comprising a dual curable polysiloxane according to the present invention.

A dual-curable polysiloxane adhesive comprises the dual-curable polysiloxane disclosed by the invention.

The invention has the beneficial effects that:

1. the method provided by the invention avoids the generation of acrylate substances, improves the end capping efficiency of hydroxyl groups by using two catalysts, namely acid and alkali, and can effectively reduce the energy required by photocuring by introducing acryloyl oxygen groups into side groups;

2. the polymer prepared by the method provided by the invention has excellent resistance to damp-heat aging;

3. the synthetic route provided by the invention can avoid the generation of acrylic ester, and the residue of silicon hydroxyl is less than 1%.

Detailed Description

The following examples are given for the purpose of further illustrating the invention and are not to be construed as limiting in practice.

In the examples, test methods for methyl acrylate: testing with dichloromethane as solvent using gas chromatography;

the method for testing the residual quantity of the silicon hydroxyl comprises the following steps: testing by nuclear magnetic resonance (29 Si-NMR);

the photocuring energy test method comprises the following steps: preparing a product from the polymer according to a uniform formula, coating the product into a coating with the thickness of 20 +/-2 microns, irradiating a sample by using an LED light source capable of adjusting ultraviolet energy, and testing the light intensity required by surface drying;

the damp-heat aging test method comprises the following steps: and (3) placing the cured sample into a constant temperature and humidity experimental box under the conditions of 85% RH and 85 ℃ for continuous aging for a certain time, and observing surface change and testing performance.

The withstand voltage test method comprises the following steps: the test sample can withstand the maximum voltage for 1 minute using a pressure tester.

Example 1

Taking a 1000ml four-mouth flask, fully drying, adding 500g of hydroxyl-terminated polysiloxane with the viscosity of 70cP, starting stirring for 300r/min, vacuumizing and dewatering for 60min at 80 ℃, cooling to 50 ℃, adding 23g of dimethoxydichloropropylsilane, stirring for 15min, adding 0.7g of acetic acid, reacting for 3h, adding 46g of chloropropyltrimethoxysilane, reacting for 2h, removing low boiling at 100 ℃ and 5mbar, adding 0.015g of p-hydroxyanisole and 20g of sodium acrylate into the obtained product, stirring uniformly, adding 2.5g of tetramethylammonium hydroxide, heating to 80 ℃, reacting for 3h, heating to 150 ℃, extracting low boiling at 5mbar, filtering at positive pressure to obtain a product I, testing that the silicon hydroxyl residue is 0.7%, and methyl acrylate is not detected.

Example 2

Taking a 1000ml four-mouth flask, fully drying, adding 500g of hydroxyl-terminated polysiloxane with the viscosity of 200cP, starting stirring for 300r/min, vacuumizing and dewatering for 60min at the temperature of 100 ℃, cooling to 60 ℃, adding 18g of dimethoxydichloropropylsilane, stirring for 15min, adding 0.5g of phosphoric acid, reacting for 3h, adding 38g of chloropropyltrimethoxysilane, reacting for 2h, removing low boiling under the conditions of 100 ℃ and 5mbar, adding 0.01g of N, N-diethylhydroxylamine and 16g of sodium acrylate into the obtained product, uniformly stirring, adding 2.5g of tetramethylammonium hydroxide, heating to 80 ℃, reacting for 3h, heating to 145 ℃, extracting low boiling under the conditions of 5mbar, filtering under positive pressure to obtain a product II, testing that the silicon hydroxyl residue is 0.8%, and not detecting methyl acrylate.

Example 3

Taking a 1000ml four-mouth flask, fully drying, adding 500g of hydroxyl-terminated polysiloxane with the viscosity of 100cP, starting stirring for 300r/min, vacuumizing and dewatering for 60min at 90 ℃, cooling to 70 ℃, adding 20.5g of dimethoxydichloropropylsilane, stirring for 15min, adding 0.6g of phosphoric acid, reacting for 4h, adding 42g of chloropropyltrimethoxysilane, reacting for 3h, removing low boiling at 110 ℃ and 6mbar, adding 0.015g of p-hydroxyanisole and 18g of sodium acrylate into the obtained product, stirring uniformly, adding 2.6g of tetramethylammonium hydroxide, heating to 80 ℃, reacting for 4h, heating to 150 ℃, extracting low boiling at 5mbar, filtering at positive pressure to obtain a product III, testing that the silicon hydroxyl residue is 0.6%, and methyl acrylate is not detected.

Comparative example 1

Taking 1000ml four-neck flask, fully drying, adding 500g of hydroxyl-terminated polysiloxane with the viscosity of 200cP, starting stirring for 300r/min, vacuumizing and dewatering for 60min at the temperature of 80 ℃, cooling to 60 ℃, adding 46g of acryloyloxypropyl trimethoxysilane and 0.05g of p-hydroxyanisole, stirring for 15min in a nitrogen atmosphere, adding 1g of lithium hydroxide methanol solution (5 wt%), reacting for 3h, cooling to room temperature, adding 3g of stearic acid for neutralization for 30min, removing low-boiling components at the temperature of 50 ℃ and under the condition of 10mbar, adding 5g of diatomite as a filter aid into the obtained product, and filtering under positive pressure to obtain a product IV. It was found to have a methyl acrylate content of 50000ppm and a residual content of Si-OH groups of 7.1%.

Comparative example 2

Taking 1000ml of a four-neck flask, fully drying, adding 500g of hydroxyl-terminated polysiloxane with the viscosity of 100cP, starting stirring for 300r/min, vacuumizing and dewatering for 60min at 90 ℃, cooling to 70 ℃, adding 50g of chloropropyl trimethoxy silane, stirring for 15min, adding 0.6g of phosphoric acid, reacting for 3h, removing low boiling at 110 ℃ and 6mbar, adding 0.015g of p-hydroxyanisole and 21g of sodium acrylate into the obtained product, uniformly stirring, adding 2.6g of tetramethyl ammonium hydroxide, heating to 80 ℃, reacting for 4h, heating to 150 ℃, extracting low boiling under 5mbar, filtering under positive pressure to obtain a product V, testing that the silicon hydroxyl residue is 0.9%, and methyl acrylate is not detected.

Application example 1

Taking 50g of the product I, adding 1g of 2-hydroxy-2-methyl-1-phenyl-1-acetone, 0.5g of dibutyltin dilaurate and 2.5g of vinyl trimethoxy silane, stirring uniformly in a nitrogen atmosphere, defoaming the mixture, clarifying, transparentizing, having no pungent smell, obtaining a film with the thickness of 25-100 mu m by using a spraying machine, and using 700mJ/cm²Curing an LED light source with energy to obtain a surface dry transparent solid, putting 3g of the mixture into an LED ultraviolet curing box for curing to obtain a transparent adhesive tape, wherein the required light curing energy is 700mJ/cm²After the completely cured film and the adhesive tape are subjected to damp heat aging (85% RH and 85 ℃) for 2000 hours, the surface of the film and the adhesive tape are free from bubbling and peeling, and the withstand voltage is higher than 1500V.

Application example 2

Taking 50g of the product II, adding 1g of 2-hydroxy-2-methyl-1-phenyl-1-acetone, 0.5g of dibutyltin dilaurate and 2.5g of vinyl trimethoxy silane, stirring uniformly in a nitrogen atmosphere, obtaining a mixture with good uniformity and no pungent smell after defoaming, obtaining a film with the thickness of 120-fold ion of 200 mu m by using a spraying machine, and using 750mJ/cm²Curing an LED light source with energy to obtain a surface dry transparent solid, putting 3g of the mixture into an LED ultraviolet curing box for curing to obtain a transparent adhesive tape, wherein the light curing energy is 750mJ/cm²After the completely cured film and the adhesive tape are subjected to damp heat aging (85% RH and 85 ℃) for 2000 hours, the surface of the film and the adhesive tape are free from bubbling and peeling, and the voltage resistance is higher than 1500V.

Application example 3

Taking 50g of the product III, adding 1g of 2-hydroxy-2-methyl-1-phenyl-1-acetone, 0.5g of dibutyltin dilaurate and 2.5g of vinyl trimethoxy silane, stirring uniformly in a nitrogen atmosphere, obtaining a mixture with good uniformity and no pungent smell after defoaming, obtaining a film with the thickness of 75-150 mu m by using a spraying machine, and using 750mJ/cm²LED light source of energyCuring to obtain a surface dry transparent solid, putting 3g of the mixture into an LED ultraviolet curing box for curing to obtain a transparent adhesive tape, wherein the required light curing energy is 750mJ/cm²After the completely cured adhesive film and adhesive tape are subjected to damp heat aging (85% RH and 85 ℃) for 2000 hours, the surface does not bubble or peel, and the withstand voltage is higher than 1500V.

Application example 4 (comparison)

Taking 50g of product IV, adding 1g of 2-hydroxy-2-methyl-1-phenyl-1-acetone, 0.5g of dibutyltin dilaurate and 2.5g of vinyl trimethoxy silane, stirring uniformly in a nitrogen atmosphere, wherein the mixture has strong pungent smell, and the use amount of the mixture is 3000mJ/cm²Curing by an energy LED light source to obtain a surface-dried transparent solid, wherein the corners of the completely cured film are peeled after 2000 hours of damp heat aging (85% RH and 85 ℃), and the withstand voltage is lower than 1000V.

Application example 5 (comparison)

Taking 50g of the product V, adding 1g of 2-hydroxy-2-methyl-1-phenyl-1-acetone, 0.5g of dibutyltin dilaurate and 2.5g of vinyl trimethoxy silane, stirring uniformly under nitrogen atmosphere, and using 2600mJ/cm²Curing by an energy LED light source to obtain a surface-dried transparent solid, wherein the corner of the completely cured film is peeled after 2000 hours of damp heat aging (85% RH and 85 ℃), and the withstand voltage is lower than 1200V.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.