Recyclable self-repairing polyurethane organic silicon resin with excellent photocuring and photoresponse performance and preparation method of recyclable self-repairing polyurethane organic silicon resin

Abstract

The invention discloses recyclable self-repairing polyurethane organic silicon resin with excellent photocuring and photoresponse performance and a preparation method thereof, and belongs to the technical field of photoresponse materials. The polyurethane organic silicon resin is prepared from the following raw materials: polymeric monomers (a propyl alcohol substituted azobenzene monomer and hydroxyethyl acrylate), diisocyanate, double-end hydroxypropyl silicone oil, bis (2-hydroxyethyl) disulfide, triethanolamine, a catalyst and a polymerization inhibitor. The material prepared by the invention contains a reversible light response azobenzene structure, a dynamic reversible bond disulfide bond and an acrylate structure, and is endowed with excellent light responsiveness, self-repairing performance and recoverability. In addition, the material prepared by the invention also has a siloxane bond structure, and complete upgrading and recycling of the material are realized through rearrangement reaction of silicon-oxygen bonds under the conditions of high temperature and alkali catalysis.

Description

Technical Field

[0001] The present invention belongs to the technical field of photoresponsive materials, and more specifically relates to a recyclable and reusable self-repairing polyurethane silicone resin with excellent photocuring and photoresponsive properties and a preparation method thereof. Background Art

[0002] Polyurethane silicone resin is widely used in many fields because it contains a large number of silicon-oxygen bonds in its structure, which makes it heat-resistant, cold-resistant, electrically insulating and chemically stable. However, during long-term use, the material will inevitably be damaged, making it unable to effectively perform its functions and even causing huge economic losses. Self-healing materials can repair the damage suffered by the material during use, effectively extending its service life while ensuring the performance of the material.

[0003] Self-healing materials can be divided into external self-healing materials and intrinsic self-healing materials according to their repair mechanism. External self-healing materials embed microcapsules or microvascular networks inside or on the surface of the material. When the material is damaged, the repair agent in the microcapsules or microvascular networks is released and reacts with the catalyst to achieve the repair of the material. The number of repairs of external self-healing materials is usually limited, which will have a certain impact on the service life of the material. Intrinsic self-healing materials rely on their own chemical structure or physical properties to achieve self-repair. Such materials usually contain reversible chemical bonds (such as dynamic covalent bonds, hydrogen bonds, metal coordination bonds, etc.). When the material is damaged, these reversible bonds can be reformed to achieve self-repair. The number of repairs of intrinsic self-healing materials is greater than that of external self-healing materials.

[0004] At present, the research on self-repairing mainly focuses on thermal response self-repairing, but the repair range of thermal response self-repairing is limited, and higher temperatures may damage the structure of the material itself. In addition, the cost of polyurethane silicone materials is high and difficult to degrade, which is not in line with the concept of green development and sustainable development, so there is an urgent need to recycle polyurethane silicone materials. And the polyurethane silicone materials recovered by conventional material recycling methods are difficult to achieve the performance of the raw materials, which reduces the use value of the recycled materials. Therefore, it is of great significance to develop a recyclable and reusable self-repairing polyurethane silicone resin on the basis of ensuring excellent photocuring and photoresponsive properties. Summary of the invention

[0005] The purpose of the present invention is to provide a recyclable and reusable self-healing polyurethane silicone resin with excellent photocuring and photoresponsive properties and a preparation method thereof, so as to solve the problems existing in the above-mentioned prior art and ensure that the performance of the self-healing polyurethane silicone resin after recycling and reuse is equivalent to or even higher than the initial performance.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] One of the technical solutions of the present invention is to provide a recyclable and self-repairing polyurethane silicone resin, comprising the following preparation raw materials in molar fractions:

[0008] 3 to 10 mmoles of polymerizable monomers, 0.02 to 0.05 moles of diisocyanate, 0.01 to 0.03 moles of double-terminal hydroxypropyl silicone oil, 0.01 to 0.03 moles of bis(2-hydroxyethyl) disulfide, and 1 to 5 mmoles of triethanolamine;

[0009] The polymerizable monomers include propanol-substituted azobenzene monomers and hydroxyethyl acrylate, and the mass ratio of the propanol-substituted azobenzene monomers to the hydroxyethyl acrylate is 2.2:1 to 1:1.06;

[0010] The raw materials for preparing the recyclable and reusable self-healing polyurethane silicone resin also include a catalyst and an inhibitor; the amount of the catalyst is preferably 0.2-0.6% of the total mass of the polymerized monomer, diisocyanate, bi-terminal hydroxypropyl silicone oil, bis(2-hydroxyethyl) disulfide and triethanolamine, and more preferably 0.4-0.5% of the total mass of the polymerized monomer, diisocyanate, bi-terminal hydroxypropyl silicone oil, bis(2-hydroxyethyl) disulfide and triethanolamine; the amount of the inhibitor is preferably 0.1-0.5% of the total mass of the polymerized monomer, diisocyanate, bi-terminal hydroxypropyl silicone oil, bis(2-hydroxyethyl) disulfide and triethanolamine, and more preferably 0.3-0.4% of the total mass of the polymerized monomer, diisocyanate, bi-terminal hydroxypropyl silicone oil, bis(2-hydroxyethyl) disulfide and triethanolamine.

[0011] The present invention ensures that the prepared polyurethane silicone resin has excellent photocuring and photoresponsive properties through specific selection of raw materials, and also ensures that the performance of the self-repairing polyurethane silicone resin after recycling is equivalent to or even higher than the initial performance; wherein the diisocyanate reacts with other raw materials containing hydroxyl groups to form carbamate groups, which work together with other soft and hard segments in the material to ensure that the synthesized polyurethane material has excellent wear resistance, high elasticity and good designability; the hydroxyethyl acrylate and propanol substituted azobenzene monomers are both compounds with hydroxyl end groups, and the double bonds therein can quickly participate in free radical polymerization reactions to form polymers, making the reaction more complete; the hydroxyethyl acrylate and propanol substituted azobenzene monomers The composite use of substituted azobenzene monomers can obtain a curable material; the bis(2-hydroxyethyl) disulfide allows the resin structure to contain a disulfide bond, and the disulfide bond structure can ensure that the resin has more excellent self-healing and recyclable properties; the triethanolamine is a three-terminal hydroxyl monomer, which can react with the linear polyurethane silicone resin molecular chain to form a symmetrical branched structure, which has a lower viscosity than the linear polyurethane silicone resin material of the same molecular weight and is more convenient for subsequent processing of the material; the siloxy main chain structure of the double-terminal hydroxypropyl silicone oil provides a siloxane bond structure in the material, and the rearrangement reaction of the siloxane bond under high temperature and base catalysis conditions can achieve complete upgrading and recycling of the material, so that the performance of the polyurethane silicone resin after recycling treatment is higher than the initial performance.

[0012] The present invention can ensure sufficient reaction, improve production efficiency and avoid gelation of the system by controlling the dosage of the catalyst and the inhibitor. If the dosage of the catalyst is too high, the system will experience gelation, while if the dosage is too low, the reaction time will be long, which will reduce production efficiency. If the dosage of the inhibitor is too low, the inhibition effect will be poor and the system will experience gelation, while if the dosage is too high, the resin light curing reaction will be slow or the curing will be incomplete.

[0013] Preferably, the preparation of the propanol substituted azobenzene monomer comprises the following steps:

[0014] Mixing 4-hydroxyazobenzene, potassium carbonate, bromopropanol and a solvent and heating the mixture for reaction to obtain the propanol-substituted azobenzene monomer;

[0015] The molar ratio of the 4-hydroxyazobenzene, potassium carbonate and bromopropanol is 0.5-1:1-1.5:0.5-1; and the temperature of the heating reaction is 65-75°C.

[0016] The present invention does not impose any special restrictions on the type and amount of solvent used in the preparation process of the propanol-substituted azobenzene monomer, as long as the solvent can dissolve the reaction raw materials and the reaction can proceed smoothly.

[0017] The synthetic reaction formula of the propanol-substituted azobenzene monomer of the present invention is as follows:

[0018]

[0019] Preferably, the diisocyanate includes isophorone diisocyanate or trimethylhexamethylene diisocyanate; the molecular weight of the double-terminal hydroxypropyl silicone oil is 1000-2000 g / mol; the catalyst includes dibutyltin dilaurate and / or bismuth neodecanoate; and the inhibitor includes 4-methoxyphenol and / or hydroquinone.

[0020] The second technical solution of the present invention is to provide a method for preparing the above-mentioned recyclable and self-repairing polyurethane silicone resin, comprising the following steps:

[0021] The double-terminal hydroxypropyl silicone oil, bis(2-hydroxyethyl) disulfide, diisocyanate, a catalyst and an organic solvent are mixed and then subjected to a prepolymerization reaction to obtain a polyurethane silicone prepolymer;

[0022] The polyurethane silicone prepolymer, the polymerization monomer, the base catalyst, the polymerization inhibitor and the organic solvent are mixed and then subjected to a first reaction to obtain an intermediate product;

[0023] The intermediate product, triethanolamine and an organic solvent are mixed and then subjected to a second reaction to obtain the recyclable and reusable self-healing polyurethane silicone resin.

[0024] The synthetic reaction formula of the recyclable self-repairing polyurethane silicone resin of the present invention is as follows:

[0025]

[0026] ; Wherein, the structural formula of R1 is: The structural formula of R2 is: The independent structural formula of R3 is: When the usage ratio of propanol substituted azobenzene monomer and hydroxyethyl acrylate is different, azobenzene and ethyl acrylate The amount of substitution in the recyclable self-healing polyurethane silicone resin is also different; the structural formula of R4 is:

[0027]

[0028] Preferably, the organic solvent independently comprises acetone and / or N,N-dimethylformamide; and the base catalyst comprises tetramethylammonium hydroxide.

[0029] Preferably, the amount of the base catalyst used is 0.2 to 1‰ of the total mass of the polymerizable monomer, diisocyanate, double-terminated hydroxypropyl silicone oil, bis(2-hydroxyethyl) disulfide and triethanolamine.

[0030] Preferably, the temperature of the prepolymerization reaction is 55-65° C., and the time of the prepolymerization reaction is 5-6 hours; the temperature of the first reaction and the second reaction are independently 50-70° C., and the time of the first reaction and the second reaction are independently 3-5 hours.

[0031] The third technical solution of the present invention is to provide a recycling method for the above-mentioned recyclable and reusable self-repairing polyurethane silicone resin, comprising the following steps:

[0032] The recyclable and reusable self-repairing polyurethane silicone resin to be recycled, tetramethyldivinyldisiloxane, tetramethylammonium hydroxide and a solvent are mixed and heated to react to obtain a vinyl-terminated polyurethane silicone recycling resin;

[0033] The polyurethane organosilicon recycled resin with terminal vinyl group, hydrogen-containing silicone oil and ethanol-modified chloroplatinic acid catalyst are mixed and then cured to obtain a reusable polyurethane organosilicon material.

[0034] Preferably, the mass ratio of the recyclable and reusable self-healing polyurethane silicone resin, tetramethyldivinyldisiloxane and tetramethylammonium hydroxide to be recycled is 5:0.02:0.01 to 5:0.06:0.01; the vinyl content in the vinyl-terminated polyurethane silicone recycled resin is 0.1 to 0.3 wt%.

[0035] Preferably, the mass ratio of the vinyl-terminated polyurethane organosilicon recovery resin, hydrogen-containing silicone oil and ethanol-modified chloroplatinic acid catalyst is 5.05:0.075:0.016 to 5.05:0.187:0.016; the silicon hydrogen content in the hydrogen-containing silicone oil is 0.2 to 0.5 wt%.

[0036] Preferably, the temperature of the heating reaction is 80-110° C., and the heating reaction time is 5-7 hours; the temperature of the curing is 130-160° C., and the curing time is 20-30 minutes.

[0037] The present invention does not impose any special restrictions on the type and amount of solvent used in the recycling method of the recyclable and reusable self-healing polyurethane silicone resin, as long as it can dissolve the reaction raw materials and the reaction can proceed smoothly.

[0038] The present invention discloses the following technical effects:

[0039] 1. The recyclable and self-repairing polyurethane silicone resin of the present invention has a symmetrical branched structure and has a lower viscosity than a linear polyurethane silicone resin material with the same molecular weight, making it easier to process the material later.

[0040] 2. The recyclable and reusable self-repairing polyurethane silicone resin of the present invention is prepared by using a polymer monomer with a hydroxyl terminal group and a disulfide compound, so that the polyurethane silicone resin has the ability of light-responsive self-repairing and can achieve self-repairing in a short time.

[0041] 3. The recyclable self-healing polyurethane silicone resin of the present invention contains a reversible photoresponsive azobenzene structure, a dynamically reversible disulfide bond and an acrylate structure, which endows the material with excellent photoresponsiveness, self-healing properties and recyclability. In addition, the recyclable self-healing polyurethane silicone resin of the present invention also has a siloxane bond structure, and the complete upgrading and recycling of the material is achieved through the rearrangement reaction of the silicon-oxygen bond under high temperature and base catalysis conditions.

[0042] 4. The recyclable and self-healing polyurethane silicone resin of the present invention can realize the upgraded recycling of the resin, and the performance of the material after upgraded recycling is better than that of the material before recycling. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is the NMR spectrum of the propanol-substituted azobenzene monomer obtained in Example 1;

[0044] Figure 2 The infrared spectra of the propanol-substituted azobenzene, isophorone diisocyanate and the resulting product described in Example 2;

[0045] Figure 3 The stress-strain curves of the cured specimens prepared from the polyurethane silicone resins obtained in Examples 2 to 5 and Comparative Example 1;

[0046] Figure 4 The self-healing performance test results of the polyurethane silicone resin obtained in Examples 2 to 5 and Comparative Examples 1 to 2 are shown in FIG.

[0047] Figure 5 The physical pictures of the cured polyurethane organosilicon resin to be recycled as described in Examples 6 to 10 and the physical pictures of the vinyl-terminated polyurethane organosilicon recycled resin obtained through upcycling and dissolving in toluene;

[0048] Figure 6 These are stress-strain curves of the upgraded recycled polyurethane silicone materials obtained in Examples 6 to 10 and the silicone material obtained in Comparative Example 3. DETAILED DESCRIPTION

[0049] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0050] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0051] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0052] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0053] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0054] Unless otherwise specified, the raw materials used in the following examples, comparative examples and effect verification examples are all commercially available products.

[0055] Example 1

[0056] The preparation of propanol substituted azobenzene comprises the following steps:

[0057] 4-Hydroxyazobenzene (17.6 g, 0.0936 mol), potassium carbonate (18.48 g, 0.1339 mol), bromopropanol (13.62 g, 0.0980 mol) and acetone (150 mL) were added into a three-necked flask, and the mixture was heated in an oil bath at 70°C for 12 h. The liquid mixture after the reaction was filtered while hot to remove potassium carbonate, and the filtrate was subjected to rotary evaporation to obtain a crude azo product, which was dissolved in a solution of methanol and water in a volume ratio of 2:1 and recrystallized to obtain yellow propanol substituted azobenzene.

[0058] The structure of the obtained propanol-substituted azobenzene was characterized using a Bruker UAVANCEⅢ 400 MHz nuclear magnetic resonance spectrometer.

[0059] The characterization method is: dissolve the obtained propanol-substituted azobenzene in deuterated chloroform reagent (CDCl3) and use tetramethylsilane (TMS) as the internal standard. The results are as follows Figure 1 shown.

[0060] Figure 1 This is the NMR spectrum of the propanol-substituted azobenzene monomer obtained in Example 1. Figure 1 7.38ppm, 6.76ppm, and 7.82ppm are the proton peaks on the benzene ring ( Figure 1 a, b, c), 7.45ppm is the proton peak on the ortho position of the benzene ring next to the ether bond ( Figure 1 d in the middle), 3.91ppm is the proton peak on -CH2- next to the ether bond ( Figure 1 e in the middle), 1.23ppm is the proton peak on -CH2- ( Figure 1 f in the middle), 3.67ppm is the proton peak on -CH2- next to the hydroxyl group ( Figure 1 According to the characteristic peaks, its structure is consistent with the theoretical product structure, indicating that propanol-substituted azobenzene was successfully synthesized.

[0061] Example 2

[0062] This embodiment provides the preparation of polyurethane silicone resin, and the specific steps are as follows:

[0063] 20 g (0.01 mol) of dihydroxypropyl silicone oil and 1.543 g (0.01 mol) of bis (2-hydroxyethyl) disulfide were added into a four-necked flask equipped with a mechanical stirring device and a condensation reflux device and mixed evenly. A mixture of 6.66 g (0.03 mol) of isophorone diisocyanate, dibutyltin dilaurate (the amount used was 0.3% of the total mass of other raw materials except 4-methoxyphenol) and 10 mL of acetone was slowly added dropwise at 60 ° C. The mixture was kept warm for 5 h at 60 ° C to obtain a polyurethane silicone prepolymer; 0.58 g (5 mmol) of l) A mixture of hydroxyethyl acrylate, 1.28 g (5 mmol) of the propanol-substituted azobenzene prepared in Example 1, tetramethylammonium hydroxide pentahydrate (the amount used is 1‰ of the total mass of the other raw materials except dibutyltin dilaurate and 4-methoxyphenol), 4-methoxyphenol (the amount used is 0.3% of the total mass of the other raw materials except dibutyltin dilaurate) and 5 mL of acetone, reacted at 65° C. for 4 h, and finally added dropwise a mixture of 0.492 g (3.3 mmol) of triethanolamine and 5 mL of acetone, and reacted at 65° C. for 3 h to obtain a polyurethane silicone resin.

[0064] The structure of the polyurethane silicone resin prepared in this example was characterized by a German bruker Vertex 70 infrared spectrometer, and the sample was prepared by potassium bromide tableting method. The test scanning range was 4000-400 cm -1, resolution 4cm -1 , the results are as follows Figure 2 shown.

[0065] Figure 2 This is the infrared spectrum of the propanol-substituted azobenzene, isophorone diisocyanate and the resulting product described in Example 2. Figure 2 Medium 3286cm -1 The characteristic absorption peak of -OH is 2260cm -1 It is the characteristic absorption peak of -NCO. According to the characteristic peak, the characteristic peaks of hydroxyl and isocyanate in the product disappear, which proves that the polyurethane silicone resin is successfully prepared.

[0066] Example 3

[0067] This embodiment provides the preparation of polyurethane silicone resin, and the specific steps are as follows:

[0068] 20 g (0.01 mol) of dihydroxypropyl silicone oil and 1.543 g (0.01 mol) of bis (2-hydroxyethyl) disulfide were added to a four-necked flask equipped with a mechanical stirring device and a condensation reflux device and mixed evenly. A mixture of 6.308 g (0.03 mol) of trimethylhexamethylene diisocyanate, dibutyltin dilaurate (the amount used was 0.3% of the total mass of other raw materials except 4-methoxyphenol) and 10 mL of acetone was slowly added dropwise at 60 ° C. The mixture was kept warm for 5 h at 60 ° C to obtain a polyurethane silicone prepolymer; 0.58 g (5 m A mixture of 1.28 g (5 mmol) of hydroxyethyl acrylate, 1.28 g (5 mmol) of the propanol-substituted azobenzene prepared in Example 1, tetramethylammonium hydroxide pentahydrate (the amount used is 1‰ of the total mass of the other raw materials except dibutyltin dilaurate and 4-methoxyphenol), 4-methoxyphenol (the amount used is 0.3% of the total mass of the other raw materials except dibutyltin dilaurate) and 5 mL of acetone, reacted at 65° C. for 4 h, and finally added dropwise a mixture of 0.492 g (3.3 mmol) of triethanolamine and 5 ml of acetone, and reacted at 65° C. for 3 h to obtain a polyurethane silicone resin.

[0069] Example 4

[0070] This embodiment provides the preparation of polyurethane silicone resin, and the specific steps are as follows:

[0071] 20 g (0.01 mol) of dihydroxypropyl silicone oil and 1.543 g (0.01 mol) of bis (2-hydroxyethyl) disulfide were added into a four-necked flask equipped with a mechanical stirring device and a condensation reflux device and mixed evenly. A mixture of 6.66 g (0.03 mol) of isophorone diisocyanate, dibutyltin dilaurate (the amount used was 0.3% of the total mass of other raw materials except 4-methoxyphenol) and 10 mL of acetone was slowly added dropwise at 60 ° C. The mixture was kept warm for 5 h at 60 ° C to obtain a polyurethane silicone prepolymer; 0.696 g (6 mmol) of l) A mixture of hydroxyethyl acrylate, 1.024 g (4 mmol) of the propanol-substituted azobenzene prepared in Example 1, tetramethylammonium hydroxide pentahydrate (the amount used is 1‰ of the total mass of the other raw materials except dibutyltin dilaurate and 4-methoxyphenol), 4-methoxyphenol (the amount used is 0.3% of the total mass of the other raw materials except dibutyltin dilaurate) and 5 mL of acetone, reacted at 65° C. for 4 h, and finally added dropwise a mixture of 0.492 g (3.3 mmol) of triethanolamine and 5 ml of acetone, and reacted at 65° C. for 3 h to obtain a polyurethane silicone resin.

[0072] Example 5

[0073] This embodiment provides the preparation of polyurethane silicone resin, and the specific steps are as follows:

[0074] 20 g (0.01 mol) of dihydroxypropyl silicone oil and 1.543 g (0.01 mol) of bis (2-hydroxyethyl) disulfide were added into a four-necked flask equipped with a mechanical stirring device and a condensation reflux device and mixed evenly. A mixture of 6.66 g (0.03 mol) of isophorone diisocyanate, dibutyltin dilaurate (the amount used was 0.3% of the total mass of other raw materials except 4-methoxyphenol) and 10 mL of acetone was slowly added dropwise at 60 ° C. The mixture was kept warm for 5 h at 60 ° C to obtain a polyurethane silicone prepolymer; 0.812 g (7 mmol) of l) A mixture of hydroxyethyl acrylate, 0.768 g (3 mmol) of the propanol-substituted azobenzene prepared in Example 1, tetramethylammonium hydroxide pentahydrate (the amount used is 1‰ of the total mass of the other raw materials except dibutyltin dilaurate and 4-methoxyphenol), 4-methoxyphenol (the amount used is 0.3% of the total mass of the other raw materials except dibutyltin dilaurate) and 5 mL of acetone, reacted at 65° C. for 4 h, and finally added dropwise a mixture of 0.492 g (3.3 mmol) of triethanolamine and 5 ml of acetone, and reacted at 65° C. for 3 h to obtain a polyurethane silicone resin.

[0075] Comparative Example 1

[0076] This comparative example provides the preparation of polyurethane silicone resin, and the specific steps are as follows:

[0077] The difference from Example 2 is that "0.58 g (5 mmol) of hydroxyethyl acrylate and 1.28 g (5 mmol) of propanol-substituted azobenzene prepared in Example 1" are replaced by "1.16 g (10 mmol) of hydroxyethyl acrylate", and the rest is the same as Example 2.

[0078] Comparative Example 2

[0079] This comparative example provides the preparation of polyurethane silicone resin, and the specific steps are as follows:

[0080] The difference from Example 2 is that "0.58 g (5 mmol) of hydroxyethyl acrylate and 1.28 g (5 mmol) of propanol-substituted azobenzene prepared in Example 1" are replaced by "12.56 g (10 mmol) of propanol-substituted azobenzene prepared in Example 1", and the rest is the same as Example 2.

[0081] Effect verification example 1

[0082] The resins prepared in Examples 2 to 5 and Comparative Examples 1 to 2 were made into light-responsive self-repairing coatings and cured strips, and the preparation method was as follows:

[0083] The resins prepared in Examples 2 to 5 and Comparative Examples 1 to 2 were respectively mixed with the photoinitiator 1173 (the photoinitiator 1173 accounted for 4% of the mass of the resin), and were quickly stirred to be evenly dispersed for later use.

[0084] Preparation of photoresponsive self-healing coating: The above-mentioned evenly dispersed mixture was placed on a glass slide and evenly coated with a 250 μm paint film preparation device, then placed at room temperature to allow the solvent to evaporate, and light-cured (30 s) using an LED ultraviolet lamp to obtain a photoresponsive self-healing coating.

[0085] Preparation of cured specimens: Pour the above-mentioned uniformly dispersed mixture into a dumbbell-shaped mold, evaporate the solvent completely, and use an LED ultraviolet lamp (radiation intensity of 800mW / cm 2 ) was photocured (1 min) to obtain a cured specimen.

[0086] The performance of the light-responsive self-healing coating and the cured specimen prepared in this effect verification example was tested. The specific test method is as follows:

[0087] 1. Stress-strain test:

[0088] Refer to GB / T 1040-2006 standard test curing specimens, the results are as follows Figure 3 shown.

[0089] 2. Self-repair performance test:

[0090] A scalpel was used to lightly scratch a clearly visible scratch on the photoresponsive self-healing coating, and the sample was irradiated under an LED UV lamp (radiation intensity was 2100 mW / cm 2 After the photoresponsive self-healing coating was cooled, the self-healing process of the photoresponsive self-healing coating was observed and photographed using a 5x objective lens of an MP41 polarizing microscope to study the self-healing behavior of polyurethane silicone resins with different azobenzene structure contents. The results are as follows Figure 4 shown.

[0091] Figure 3 The stress-strain curves of the cured specimens prepared from the polyurethane silicone resin obtained in Examples 2 to 5 and Comparative Example 1 are shown. Figure 4 The self-healing performance test results of the polyurethane silicone resin obtained in Examples 2 to 5 and Comparative Examples 1 to 2 are shown in FIG. Figure 3 and Figure 4 It can be seen that during the preparation of polyurethane silicone resin, as the content of carbon-carbon double bonds gradually increases, the tensile strength of the cured specimen gradually increases; among them, the resin end groups prepared in Comparative Example 2 are all azobenzene structures, and the molecular structure does not contain carbon-carbon double bonds. The resin cannot be cured and becomes a viscous liquid, making it difficult to perform stress-strain performance tests. As the content of azobenzene structure in the resin increases, the repair time of scratches on the coating gradually shortens; among them, the resin of Comparative Example 1 does not contain azobenzene structure and has no light response effect, so it is difficult for the coating to achieve self-repair in a short time.

[0092] Example 6

[0093] This embodiment provides a recycling method for polyurethane silicone resin, and the specific steps are as follows:

[0094] 5 g of the cured polyurethane silicone resin to be recovered in Example 2 was mixed with 0.035 g of tetramethyldivinyldisiloxane, 0.01 g of tetramethylammonium hydroxide pentahydrate (base catalyst) and 20 mL of toluene, reacted at 100° C. for 6 h, and then distilled under reduced pressure for 2 h to remove toluene, to obtain a vinyl-terminated polyurethane silicone recovery resin having a vinyl content of 0.2 wt %;

[0095] Take 5.05g of vinyl-terminated polyurethane silicone recycled resin, 0.104g of hydrogenated silicone oil (silicon hydrogen content is 0.36wt%) and 0.016g of ethanol-modified chloroplatinic acid catalyst (purchased from Shanghai Neutron Star Chemical Technology Co., Ltd.), mix them evenly (dichloromethane can be added during the process to adjust the viscosity to a workable viscosity), and cure them at 150°C for 30min to obtain an upgraded recycled polyurethane silicone material.

[0096] Example 7

[0097] This embodiment provides a recycling method for polyurethane silicone resin, and the specific steps are as follows:

[0098] The difference from Example 6 is that "the solidified polyurethane silicone resin to be recycled in Example 2" is replaced by "the solidified polyurethane silicone resin to be recycled in Example 3", and the rest is the same as Example 6.

[0099] Example 8

[0100] This embodiment provides a recycling method for polyurethane silicone resin, and the specific steps are as follows:

[0101] The difference from Example 6 is that "the solidified polyurethane silicone resin to be recycled in Example 2" is replaced by "the solidified polyurethane silicone resin to be recycled in Example 4", and the rest is the same as Example 6.

[0102] Example 9

[0103] This embodiment provides a recycling method for polyurethane silicone resin, and the specific steps are as follows:

[0104] The difference from Example 6 is that "the cured polyurethane silicone resin to be recycled in Example 2" is replaced by "the cured polyurethane silicone resin to be recycled in Example 5", and the rest is the same as Example 6.

[0105] Example 10

[0106] This embodiment provides a recycling method for polyurethane silicone resin, and the specific steps are as follows:

[0107] The difference from Example 6 is that "the cured polyurethane silicone resin to be recycled in Example 2" is replaced by "the cured polyurethane silicone resin to be recycled in Comparative Example 1", and the rest is the same as Example 6.

[0108] Figure 5 The following are the physical pictures of the cured polyurethane silicone resin to be recycled as described in Examples 6 to 10 and the physical pictures of the vinyl-terminated polyurethane silicone recycled resin obtained through upcycling and dissolving in toluene. Figure 5 It can be seen that the solution of the vinyl-terminated polyurethane silicone resin obtained by upgrading and recycling is dissolved in toluene in a uniform state, and the polyurethane silicone resin prepared by the present invention can achieve effective recycling.

[0109] Comparative Example 3

[0110] This comparative example provides a preparation method of a conventional organosilicon resin having the same silicon-hydrogen content as that of Example 6, and the specific steps are as follows:

[0111] 5 g of conventional vinyl silicone oil with a vinyl content of 0.2 wt.% was mixed evenly with 0.103 g of hydrogenated silicone oil (silicon hydrogen content of 0.36 wt.%) and 0.015 g of ethanol-modified chloroplatinic acid catalyst, and cured at 150° C. for 30 min to obtain a conventional silicone resin as a comparative sample.

[0112] Effect verification example 2

[0113] The upgraded recycled polyurethane silicone material obtained in Examples 6 to 10 and the silicone resin prepared in Comparative Example 3 were made into cured specimens, and the preparation method was as follows:

[0114] The upgraded recycled polyurethane silicone material obtained in Examples 6 to 10 and the silicone resin prepared in Comparative Example 3 were mixed with the photoinitiator 1173 (the photoinitiator 1173 accounted for 4% of the resin mass) and stirred rapidly to make it dispersed evenly for use. The above-mentioned evenly dispersed mixture was poured into a dumbbell-shaped mold, the solvent was completely evaporated, and an LED ultraviolet lamp (radiation intensity of 800mW / cm 2 ) was photocured (1 min) to obtain a cured specimen.

[0115] The performance test of the cured sample prepared in this effect verification example is carried out, and the specific test method is as follows:

[0116] Stress-strain testing:

[0117] Refer to GB / T 1040-2006 standard test curing specimens, the results are as follows Figure 6 shown.

[0118] Figure 6 The stress-strain curves of the upgraded recycled polyurethane silicone material obtained in Examples 6 to 10 and the silicone material obtained in Comparative Example 3 are shown. Figure 6 and Figure 3 It can be seen from the data comparison that the tensile strength of the upgraded polyurethane silicone material prepared by the present invention is higher than the tensile strength of the corresponding raw materials (polyurethane silicone resin prepared in Examples 2 to 5), and is much greater than the tensile strength of conventional silicone materials with the same vinyl content. This shows that the polyurethane silicone resin of the present invention can achieve the upgraded recycling of the resin, and the performance of the upgraded recycled material is better than that of the material before recycling.

[0119] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0120] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A recyclable and self-repairing polyurethane silicone resin, characterized in that: The preparation raw materials include the following molar fractions: 3 to 10 mmoles of polymerizable monomers, 0.02 to 0.05 moles of diisocyanate, 0.01 to 0.03 moles of double-terminal hydroxypropyl silicone oil, 0.01 to 0.03 moles of bis(2-hydroxyethyl) disulfide, and 1 to 5 mmoles of triethanolamine; The polymerizable monomers include propanol-substituted azobenzene monomers and hydroxyethyl acrylate, and the mass ratio of the propanol-substituted azobenzene monomers to the hydroxyethyl acrylate is 2.2:1 to 1:1.06; The raw materials for preparing the recyclable and reusable self-healing polyurethane silicone resin also include a catalyst and an inhibitor. The amount of the catalyst is 0.2-0.6% of the total mass of the polymerization monomer, diisocyanate, double-terminal hydroxypropyl silicone oil, bis(2-hydroxyethyl) disulfide and triethanolamine, and the amount of the inhibitor is 0.1-0.5% of the total mass of the polymerization monomer, diisocyanate, double-terminal hydroxypropyl silicone oil, bis(2-hydroxyethyl) disulfide and triethanolamine.

2. The recyclable and self-repairable polyurethane silicone resin according to claim 1, characterized in that: The preparation of the propanol substituted azobenzene monomer comprises the following steps: Mixing 4-hydroxyazobenzene, potassium carbonate, bromopropanol and a solvent and heating the mixture for reaction to obtain the propanol-substituted azobenzene monomer; and / or, the molar ratio of the 4-hydroxyazobenzene, potassium carbonate and bromopropanol is 0.5-1:1-1.5:0.5-1; and / or, the temperature of the heating reaction is 65-75°C.

3. The recyclable and self-repairable polyurethane silicone resin according to claim 1, characterized in that: The diisocyanate includes isophorone diisocyanate or trimethylhexamethylene diisocyanate; and / or the molecular weight of the double-terminal hydroxypropyl silicone oil is 1000-2000 g / mol; and / or the catalyst includes dibutyltin dilaurate and / or bismuth neodecanoate; and / or the inhibitor includes 4-methoxyphenol and / or hydroquinone.

4. The method for preparing the recyclable self-repairing polyurethane silicone resin according to any one of claims 1 to 3, characterized in that: The steps include: The double-terminal hydroxypropyl silicone oil, bis(2-hydroxyethyl) disulfide, diisocyanate, a catalyst and an organic solvent are mixed and then subjected to a prepolymerization reaction to obtain a polyurethane silicone prepolymer; The polyurethane silicone prepolymer, the polymerization monomer, the base catalyst, the polymerization inhibitor and the organic solvent are mixed and then subjected to a first reaction to obtain an intermediate product; The intermediate product, triethanolamine and an organic solvent are mixed and then subjected to a second reaction to obtain the recyclable and reusable self-healing polyurethane silicone resin.

5. The preparation method according to claim 4, characterized in that: The organic solvent independently includes acetone and / or N,N-dimethylformamide; and / or the alkaline catalyst includes tetramethylammonium hydroxide; and / or the amount of the alkaline catalyst is 0.2 to 1‰ of the total mass of the polymerization monomer, diisocyanate, double-terminated hydroxypropyl silicone oil, bis(2-hydroxyethyl) disulfide and triethanolamine.

6. The preparation method according to claim 4, characterized in that: The temperature of the prepolymerization reaction is 55-65° C., and the time of the prepolymerization reaction is 5-6 hours; and / or, the temperature of the first reaction and the second reaction are independently 50-70° C., and the time of the first reaction and the second reaction are independently 3-5 hours.

7. The recycling method of the recyclable and reusable self-repairing polyurethane silicone resin according to any one of claims 1 to 3, characterized in that: The steps include: The recyclable and reusable self-repairing polyurethane silicone resin to be recycled, tetramethyldivinyldisiloxane, tetramethylammonium hydroxide and a solvent are mixed and heated to react to obtain a vinyl-terminated polyurethane silicone recycling resin; The polyurethane organosilicon recycled resin with terminal vinyl group, hydrogen-containing silicone oil and ethanol-modified chloroplatinic acid catalyst are mixed and then cured to obtain a reusable polyurethane organosilicon material.

8. The recycling method according to claim 7, characterized in that: The mass ratio of the recyclable and reusable self-healing polyurethane silicone resin, tetramethyldivinyldisiloxane and tetramethylammonium hydroxide pentahydrate to be recycled is 5:0.02:0.01 to 5:0.06:0.01; and / or, the vinyl content in the vinyl-terminated polyurethane silicone recovery resin is 0.1 to 0.3 wt%.

9. The recycling method according to claim 7, characterized in that: The mass ratio of the vinyl-terminated polyurethane organosilicon recovery resin, hydrogen-containing silicone oil and ethanol-modified chloroplatinic acid catalyst is 5.05:0.075:0.016 to 5.05:0.187:0.016; and / or, the silicon hydrogen content in the hydrogen-containing silicone oil is 0.2 to 0.5 wt%.

10. The recycling method according to claim 7, characterized in that: The temperature of the heating reaction is 80-110° C., and the heating reaction time is 5-7 hours; and / or the temperature of the curing is 130-160° C., and the curing time is 20-30 minutes.

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