CN113105605B - UV-cured high-transparency POSS modified organic silicon-castor oil polyurethane material and preparation and application thereof - Google Patents

Abstract

The invention discloses a UV-cured high-transparency POSS modified organic silicon-castor oil polyurethane material, a preparation method thereof and application thereof in manufacturing UV-cured environment-friendly solid wood furniture paint and flexible electronic devices. The preparation method comprises the steps of carrying out copolymerization reaction on hydroxyl silsesquioxane, hydroxyl-terminated/amino-terminated polysiloxane, castor oil and diisocyanate, terminating with hydroxyl acrylate, preparing an acrylate-terminated silsesquioxane modified organosilicon-castor oil polyurethane prepolymer, uniformly mixing the silsesquioxane modified organosilicon-castor oil polyurethane prepolymer with polysiloxane containing mercaptopropyl siloxane chain links in proportion, defoaming in vacuum for 10-30 min, and carrying out UV curing for 10-120 s to obtain the UV-cured high-transparency POSS modified organosilicon-castor oil polyurethane material with the light transmittance of 95% (the light wavelength range is 400-800 nm), the hardness of 3H-9H, the tensile strength of 0.5-10.5 MPa, the initial thermal decomposition temperature of 250-290 ℃ and excellent adhesion with a base material.

Description

A kind of UV curing high transparent POSS modified organosilicon-castor oil polyurethane material and its preparation and application

technical field

The invention relates to the technical field of functional polymer materials, in particular to a UV-cured high-transparency POSS modified organosilicon-castor oil polyurethane material and its preparation and application.

Background technique

Ultraviolet (UV) curing is a new technology of energy saving and environmental protection, which has the advantages of fast curing and environmental friendliness [L.Xue, Y.Y.Zhang, Y.J.Zuo, et al., Preparation and characterization of novel UV-curing silicone rubber via thiol- ene reaction [J], Mater. Lett., 2013, 106(34): 425-427], has been widely used in important fields such as coatings, inks and electronic packaging. Traditional UV-curable polymers mostly use petrochemical raw materials. With the gradual consumption of petrochemical raw materials, petroleum resources will always be exhausted. Therefore, when the global energy crisis is becoming more and more serious, replacing petrochemical raw materials with green and cheap bio-based raw materials has become a hot spot in the research of UV-curable materials today. As an important renewable bio-based raw material, vegetable oil has attracted extensive attention in the research and application of UV-curable new materials because of its abundant sources, low toxicity, and biodegradability. Chinese invention patent application CN102633983A discloses a method for preparing a UV-curable siloxane-terminated organosilicon block polyurethane. Specifically, polyester polyol or polyether polyol, hydroxyl-terminated silicone oil and castor oil are added dropwise to aromatic Or aliphatic diisocyanate, obtain organosilicon block polyurethane prepolymer, then under organic tin catalyst, add siloxane with active hydrogen to the above organosilicon block polyurethane prepolymer, and react to obtain stable silicon Oxane-terminated silicone block polyurethane prepolymer, adding UV initiator, and UV curing can obtain silicone modified UV curing polyurethane material. Chinese invention patent ZL201610556092.0 discloses a light-curing UV coating with strong adhesion, including primer, middle paint and topcoat, which are made of castor oil-based UV-curable urethane acrylate, silicone-modified urethane acrylate It is prepared with polyether modified silicone leveling agent and UV initiator. These coatings not only have good leveling effect, but also have fast curing speed, low emission of volatile organic substances, hydrolysis resistance, low temperature resistance, good electrical insulation, and their adhesion Even better. Chinese invention patent application CN201710154932.5 uses castor oil modified polyol as extension link to prepare a UV-curable water-based polyurethane acrylate oily leather finishing agent. The finishing agent has the characteristics of low viscosity, green environmental protection, fast curing speed, etc., especially Suitable as a finishing agent for leather or artificial leather. Chinese invention patent ZL201710699373.6 uses diglycerol-based dendrimer polyurethane prepolymer, castor oil-based polyurethane prepolymer, composite active monomer, inorganic composite filler, acetyl citron tributyl ester, UV curing agent, aliphatic polymer The dual-curing solvent-free polyurethane coil coating prepared by isocyanate curing agent, hydroxyethyl methacrylate phosphate and epoxy silane coupling agent, the obtained coating product is a solvent-free environment-friendly coating with good adhesion, resistance to The advantages of MEK wipe and high and low temperature resistance. Chinese invention patent application CN202010895159.X After reacting castor oil, ricinoleic acid and esterification reaction product with diisocyanate, polyethylene glycol acrylate and polymerization inhibitor to obtain star-shaped castor oil-based water-based UV curing prepolymer, the product was Mixed with vegetable oil-based reactive non-ionic surfactant, free radical photoinitiator and cationic photoinitiator, add water and disperse evenly to obtain castor oil-based water-based photocurable non-ionic emulsion, which can be used as environmentally friendly coatings, inks and adhesives film-forming base material in the field. However, the above castor oil-based UV-curable materials are not concerned with light transmittance, and these UV-curable materials have poor thermal stability.

Transparent silicone polymer materials have a wide range of applications in flexible display, wearable devices, wireless communication, human-computer interaction, biomedical and other fields [Chen Ying, Flexible electronic technology products realize a new model of remote smart medical treatment [J], Robot Industry, 2018, 6, 82-83]. However, the tensile strength of unreinforced pure silicone transparent materials is very low (not higher than 0.5 MPa), which restricts the application of silicone optically transparent polymer materials in the field of flexible and transparent electronic devices. Although nano-silica (silica) or MQ resin is used to enhance the silicone material, the light transmittance of the material reinforced with silica is very low, and the preparation of MQ resin is poor in controllability and large in pollution.

The applicant adopts a series of silicon-containing hyperbranched mercapto polymers and acrylate-terminated polyurethane to cure in the presence of UV photoinitiator to obtain pencil hardness of 4B-2B, light transmittance at 25°C of 75.0-98%, and tensile strength of 0.5. MPa～3.0MPa temperature-sensitive fluorescent material (Chinese invention patent application CN202010096440.7); use silicon-containing hyperbranched mercapto polymer to react with acrylate-terminated polyurethane to obtain light transmittance>95% (light wavelength range 400～800nm) , flexible silicone material with hardness greater than or equal to 4B and tensile strength of 1MPa to 3.5MPa (Chinese invention patent application CN202010096461.9). Although the tensile strength of these materials is high, their thermal stability needs to be improved. The applicant also reacts the isocyanate-terminated hyperbranched organosilicon-modified polyurethane with hydroxy acrylate to obtain an acrylate group-containing organosilicon-modified polyurethane, which is UV-cured with a mercaptopropyl-containing polysiloxane to obtain a transparent solution. For materials with a light rate >90% and a hardness of 4B to 9H, although the initial thermal decomposition temperature is as high as 290 to 350 °C, the mechanical properties of the material are not good (Chinese invention patent application CN201910775983.9).

Silsesquioxane refers to an intramolecular organic-inorganic hybrid compound composed of an inorganic framework composed of two elements, silicon and oxygen, and an organic group surrounded by it. It is between 1 and 3 nm, and the average size is about 1.5 nm, which is close to the size of the chain segments and random coils of most other polymers. Introducing it into the polymer system can make the inorganic phase and the organic phase form stronger. The chemical action of the two leads to good compatibility between the two, so that the polymer matrix can be reinforced at the molecular level. Chinese invention patent ZL200510028254.5 reports a UV-curable coating containing POSS and its preparation method, which is specifically prepared by using white solid powder POSS with double bonds and diisocyanate, polyol, and catalyst-based reactive diluent in a certain proportion Although this method has the advantages of simple process, less environmental pollution, low cost and fast curing of the coating film, but the POSS used is a white solid powder, which is difficult to be uniformly dispersed in the system. Y.T.Liao et al. synthesized a block copolymer of octaphenyl double-plywood polysilsesquioxane and dimethyl polysiloxane, which can obtain a light transmittance of more than 95%, a tensile strength of about 1.5MPa, and an elongation of 17%. % transparent flexible silicone materials [Y.T.Liao, Y.C.Lin, S.W.Kuo, Highly thermally stable, transparent, and flexiblepolybenzoxazine nanocomposites by combination of double-decker-shaped polyhedral silsesquioxanes and polydimethylsiloxane[J], Macromolecules, 2017, 50(15): 5739-5747]. However, the organosilicon polymer raw materials with special structure required for such materials have a long synthesis time and low yield, which are difficult to meet the requirements of industrialization. The applicant's previous Chinese invention patent CN202010096439.4 prepared a liquid silsesquioxane with silsesquioxane as the core and polycarbosilane as the arm, and then cured it with mercapto silicone resin by UV to obtain 400-800nm The light transmittance in the light wave range reaches more than 90%, the pencil hardness is B ~ 7H, and the initial thermal decomposition of the silicone coating at 260 ° C ~ 360 ° C, but the material is brittle.

SUMMARY OF THE INVENTION

In view of the above-mentioned technical problems and the deficiencies in the art, the present invention provides a method for preparing a UV-curing high-transparency POSS-modified organosilicon-castor oil polyurethane material, which comprises hydroxyl-containing silsesquioxane and diisocyanate, Hydroxy/amino-terminated polysiloxane copolymerization reaction to prepare a silsesquioxane-modified acrylate-based organosilicon-castor oil polyurethane copolymer with a silsesquioxane segment in the main chain, which was mixed with a silsesquioxane-containing The polysiloxane of the mercaptopropyl siloxane segment is mixed uniformly in proportion and vacuum degassed for 5-30min, and then cured by UV for 10-120s to obtain light transmittance>95% (light wavelength range 400-800nm), UV-curable high-transparency POSS modified silicone-castor oil polyurethane material with hardness of 3H~9H, tensile strength of 0.5~10.5MPa, initial thermal decomposition temperature of 250~290℃, and excellent adhesion to the substrate. In the preparation method, the hydroxyl silsesquioxane participates in the copolymerization reaction, so that it is bound to the main chain of the copolymer through covalent bonds and will not be precipitated from the copolymer system, thus retaining the above advantages of silsesquioxane, overcoming The above-mentioned UV-curable materials have disadvantages such as poor thermal stability, poor mechanical properties, and low light transmittance. At the same time, the bio-based raw material castor oil is used in the system, and the hydroxyl group in the castor oil molecule is used to participate in the copolymerization reaction, which improves the mechanical properties of the silicone material and expands the application field of the bio-based material. The optically transparent organosilicon modified material has very high light transmittance and excellent tensile strength after curing, the curing process is fast, the energy consumption is low, the environment is environmentally friendly, and no photoinitiator is needed, which can save costs. The material can be used for UV-curing high-grade environmentally friendly solid wood furniture paint, and is also expected to be used in the field of flexible electronic devices.

A preparation method of UV-curing high-transparency POSS modified organosilicon-castor oil polyurethane material, comprising the steps:

(1) Mix the hydroxysilsesquioxane, amino-terminated/hydroxyl-terminated (ie, amino-terminated or hydroxyl-terminated) polysiloxane and castor oil to a temperature of 100-120 °C, decompression and dehydration, and then lower the temperature to 30-30 °C. 60°C, under the protection of an inert atmosphere, add diisobutyltin laurate, add diisocyanate dropwise to the mixture under mechanical stirring, and react to obtain an isocyanate-terminated polyurethane prepolymer, which is then added to the obtained prepolymer at 20-80°C. Hydroxy acrylate is added to the reaction, and an acrylate-terminated, silsesquioxane-modified organosilicon-polyurethane is obtained after the reaction is completed;

The diisocyanates are 2,4-toluene diisocyanate and 2,6-toluene diisocyanate isomer mixture (TDI), diphenylmethane diisocyanate (MDI), 1,6-hexamethylene diisocyanate (HDI), isomeric One or more mixtures of phorone diisocyanate (IPDI);

The added amount of the castor oil accounts for the total mass of the raw materials for preparing the acrylate-terminated, silsesquioxane-modified silicone-polyurethane (referring to the hydroxysilsesquioxane, amino-terminated/hydroxyl-terminated poly 30wt% to 40wt% of the total mass of siloxane, castor oil, diisocyanate and hydroxyacrylate);

(2) Co-hydrolysis-condensation reaction of mercaptopropyl alkoxysilane, difunctional alkoxysilane and trifunctional alkoxysilane in an organic solvent and catalyzed by an acidic catalyst at 30-80 °C for 0.5-12 h, After washing with water to neutrality, decompress at 130mmHg/170°C until no distillate comes out within 5min, to obtain clear and transparent polysiloxane containing mercaptopropylsiloxane;

The mercaptopropyl alkoxysilane is mercaptopropylmethyldimethoxysilane, mercaptopropylmethyldiethoxysilane, mercaptopropyltrimethoxysilane and mercaptopropyltriethoxysilane. one or a mixture of several;

The difunctional alkoxysilane is dimethyldimethoxysilane, dimethyldiethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, diphenyl One or more mixtures of dimethoxysilane and diphenyldiethoxysilane;

The trifunctional alkoxysilane is one or a mixture of methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane and phenyltriethoxysilane;

The organic solvent is one or more mixtures of toluene, xylene, petroleum ether, tetrahydrofuran, and butyl acetate, and its dosage is the mercaptopropyl alkoxysilane, difunctional alkoxysilane, trifunctional 0.5 to 4 times the total mass of alkoxysilane;

The acidic catalyst is one or a mixture of hydrochloric acid, sulfuric acid, trifluoromethanesulfonic acid, and p-toluenesulfonic acid, and the dosage is the mercaptopropyl alkoxysilane, difunctional alkoxysilane, trifunctional 0.05wt% to 5wt% of the total mass of functional alkoxysilane; the acidic catalyst is added in the form of an aqueous solution, wherein the amount of water used is the mercaptopropylalkoxysilane, difunctional alkoxysilane, trifunctional alkoxysilane 1 to 2.5 times the total number of moles of alkoxy groups of oxysilane;

The ratio of the number of moles of the mercaptopropyl alkoxysilane to the sum of the number of moles of other alkoxysilanes is 0.05 to 0.65:1. The molar ratio R/Si of all organic groups and silicon atoms in the base silane is 1.3～2.0:1;

(3) The acrylate-terminated, silsesquioxane-modified organosilicon-polyurethane obtained in step (1) and the polysiloxane containing mercaptopropylsiloxane units obtained in step (2) were prepared according to acrylic acid The molar ratio of ester group and mercapto group is 1～5:1 and evenly mixed, then degassed under reduced pressure at 130mmHg/25～40℃ for 5～30min, and then cured by UV for 10～120s to obtain the obtained UV-cured high-transparency POSS modified organosilicon-castor Hemp oil polyurethane material.

The preparation method of the invention comprises the following steps: after the copolymerization reaction of hydroxyl silsesquioxane with hydroxyl-terminated/amino-terminated polysiloxane, castor oil and diisocyanate, the hydroxyacrylate-terminated silsesquioxane is prepared Oxane-modified organosilicon-castor oil polyurethane prepolymer, mix it uniformly with polysiloxane containing mercaptopropyl siloxane in proportion, vacuum degassing for 5-30min, and then cure by UV for 10-120s , UV curing with light transmittance>95% (light wavelength range 400～800nm), hardness 3H～9H, tensile strength 0.5～10.5MPa, initial thermal decomposition temperature 250～290℃, and excellent adhesion to the substrate can be obtained Highly transparent POSS modified silicone-castor oil polyurethane material.

Preferably, in step (1), the hydroxysilsesquioxane is one or a mixture of several silsesquioxanes represented by the following formulas (I) to (III):

(I), denoted as silsesquioxane 1;

(II), denoted as silsesquioxane 2;

(III), denoted as silsesquioxane 3.

Preferably, in step (1), the amino-terminated/hydroxyl-terminated polysiloxane is dimethyl polysiloxane with amino groups at both ends, methylphenyl polysiloxane with amino groups at both ends, One or more mixtures of dimethyl polysiloxane with hydroxyl groups at both ends and methylphenyl polysiloxane with hydroxyl groups at both ends.

In step (1), the molecular weight of the amino-terminated/hydroxyl-terminated polysiloxane is preferably 800-15000, more preferably 1000-5000.

In step (1), the mass of the hydroxysilsesquioxane is preferably 0.5% to 20% of the mass of the amino-terminated/hydroxyl-terminated polysiloxane, more preferably 1% to 10%.

Preferably, in step (1), the amount of the diisobutyltin laurate added accounts for the total mass of the preparation of the acrylate-terminated, silsesquioxane-modified silicone-polyurethane raw material (referring to the hydroxyl group 0.1 wt% to 0.4 wt% of the total mass of silsesquioxane, amino-terminated/hydroxyl-terminated polysiloxane, castor oil, diisocyanate and hydroxyacrylate).

In step (1), the diisocyanate is preferably the sum of the moles of all amino groups and hydroxyl groups in the hydroxysilsesquioxane, amino-terminated/hydroxyl-terminated polysiloxane, and castor oil according to the number of moles of isocyanate groups. 1.05 to 3.5 times as much, more preferably 1.5 to 2.5 times as much.

Preferably, in step (1), the hydroxy acrylate is hydroxyethyl methacrylate, hydroxypropyl methacrylate, 4-hydroxyphenyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate and acrylic acid One or more mixtures of -4-hydroxybutyl esters.

Preferably, in step (1), the hydroxy acrylate is added according to the mole number of hydroxyl groups equal to the mole number of isocyanate groups of the prepolymer when no hydroxy acrylate is added.

Preferably, in step (2), the reaction temperature of the co-hydrolysis-condensation reaction is 30-78° C., and the reaction time is 0.5-8 h.

The present invention also provides the UV-curing high-transparency POSS modified organosilicon-castor oil polyurethane material prepared by the preparation method. The UV-curable high-transparency POSS modified silicone-castor oil polyurethane material has a light transmittance of >95% in the light wavelength range of 400-800 nm, a hardness of 3H-9H, a tensile strength of 0.5-10.5MPa, and an initial thermal decomposition temperature of 250 ～290°C, the water absorption rate is not more than 2.80wt%, and the water contact angle is 105.0～109.8°.

The optically transparent organosilicon modified material obtained by the invention has very high light transmittance and excellent tensile strength, and has fast curing process, low energy consumption, environmental protection, no need to add photoinitiator, and can save cost. The material can be used for UV-curing high-grade environmentally friendly solid wood furniture paint, and is also expected to be used in the field of flexible electronic devices.

The invention also provides the application of the UV-cured high-transparency POSS modified organosilicon-castor oil polyurethane material in the production of UV-cured environment-friendly solid wood furniture paint and flexible electronic devices.

Compared with the prior art, the main advantages of the present invention include:

1. The tensile strength of the unreinforced pure silicone transparent material is very low (not higher than 0.5MPa), and has no practical value except as a filling material, and the UV-cured high-transparency POSS modified organic material prepared by the present invention has no practical value. Silicon-castor oil polyurethane material has a tensile strength of 0.5 to 10.5 MPa, a light transmittance of > 95% (light wavelength range of 400 to 800 nm), a hardness of 3H to 9H, and excellent mechanical properties.

(2) The thermal stability of the existing UV-curable material is poor, and the present invention improves the thermal stability of the UV-curable material after copolymerization and modification with silsesquioxane.

(3) The present invention uses hydroxyl silsesquioxane, castor oil, and polyurethane to copolymerize to prepare a new type of polymer material, which overcomes the precipitation of solid silsesquioxane when the existing silsesquioxane is blended to modify the UV curing material, The problem of uneven dispersion causes deterioration of material properties.

Description of drawings

Fig. 1 is the light transmittance figure of embodiment 3 different acrylate group and mercapto group molar ratio curing material;

Fig. 2 is the thermogravimetric TGA (N ₂ ) curves of the cured materials with different molar ratios of acrylate groups and mercapto groups in Example 3;

Fig. 3 is the stress-strain curve diagram of the cured material with different molar ratios of acrylate group and mercapto group in Example 3;

FIG. 4 is a photo of the material with the molar ratio of acrylate group and mercapto group of 3:1 used as UV curing solid wood furniture paint in Example 3.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that these examples are only used to illustrate the present invention and not to limit the scope of the present invention. The operation method without specifying the specific conditions in the following examples is usually in accordance with the conventional conditions, or in accordance with the conditions suggested by the manufacturer.

In the present invention, the analytical test method is as follows:

The molecular structure and purity of the raw materials were determined with a Brucker Advance-400NMR (German Brucker Company) nuclear magnetic resonance apparatus and a polarimeter (Autopol II);

Light transmittance test: The Evolution 300 UV-Vis spectrophotometer of Thermo Fisher Company in the United States tests the light transmittance of the polymer, the test wavelength range is 300-800nm, and the sample thickness is 10mm;

Tensile strength test: The experimental equipment is UH6503D microcomputer-controlled electronic tension-compression cycle reciprocating test machine produced by Youhong Measurement and Control Technology (Shanghai) Co., Ltd., the tensile speed is 2mm/min, and each film is measured 3 times, and the average value is taken.

Pencil hardness: measured according to GB/T 6739-2006 "Paint and Varnish Pencil Method Determination of Hardness of Paint Film".

Water contact angle: IL4200 contact angle measuring instrument, Germany KRUSS company, drip 2 μL of deionized water into the surface of the sample to be tested from a micro syringe, and measure the contact angle between distilled water and solid coating film in the air. Cut method to determine its value. The average value was obtained by 5 parallel measurements.

Water absorption rate: Cut the coating film into squares of a certain shape, soak it in deionized water for 24 hours at room temperature, use filter paper to absorb the water on the surface of the coating film, and calculate the water absorption rate of the coating film as follows:

Among them, B represents the water absorption rate (%), m ₁ represents the quality of the coating film before soaking, and m ₂ represents the quality of the surface liquid of the coating film after soaking with filter paper.

Example 1

1) Add 5g of silsesquioxane 1, 50g of castor oil, and 10g of hydroxyl-terminated polydimethylsiloxane with a molecular weight of 4000 to a clean 250mL four-necked flask with a thermometer, and the temperature is raised to 100-120 ℃ decompressed to 130mmHg, dehydrated for 2h, cooled to 60℃, stirred under nitrogen protection, added 0.127g diisobutyltin dilaurate, then slowly added 40g HDI, then heated to 80℃ for 3h reaction, added 22.305g Hydroxyethyl methacrylate was reacted for 3 hours to obtain a slightly yellow transparent liquid, which was an acrylate-terminated, silsesquioxane-modified silicone-polyurethane.

2) To 78.54g 3-mercaptopropyltrimethoxysilane, 48.75g dimethyldiethoxysilane, 47.98g methyltrimethoxysilane, 1.62g hexamethyldisiloxane at 50°C under mechanical stirring (According to the thiol content of 0.004mol/g, the ratio of organic group/silicon atom is 1.3) and 175g of toluene, a mixture of 56.2g of deionized water and 3.5g of 36.5wt% concentrated hydrochloric acid was added dropwise, and the dripping was completed in 0.5h. Then continue to react at 50°C for 8h, then wash with water until neutral, and remove the solvent, residual raw materials and low molecular products under reduced pressure at 130mmHg/170°C to obtain 70.5g of colorless and transparent mercapto-containing polysiloxane.

3) Take 10 g of the acrylate-terminated, silsesquioxane-modified silicone-polyurethane obtained in 1) and 1.8 g of mercapto-silicone resin in 2), mix them evenly, and degas at 130 mmHg/30°C for 20 min. UV curing, the properties of the obtained material are shown in Table 1.

Table 1 Properties of materials prepared with different UV curing times

Example 2

1) 3 g of silsesquioxane 1, 5 g of silsesquioxane 2, 50 g of castor oil, 5 g of hydroxy-terminated polydimethylsiloxane with molecular weight of 1000 and 10 g of hydroxy-terminated polydimethylsiloxane with molecular weight of 15,000. Add dimethylsiloxane into a clean 250mL four-necked flask with a thermometer inserted, heat up to 100-120°C and reduce the pressure to 130mmHg, dehydrate for 2h, then cool down to 30°C, stir under nitrogen protection, add 0.225g dimethicone isobutyltin dilaurate, then slowly add 45g IPDI, then heat up to 60°C for 8h reaction, add 26.850g hydroxypropyl methacrylate, continue to react for 8h to obtain a slightly yellow transparent liquid, which is acrylate end capping, Silsesquioxane-modified silicone-polyurethane.

2) To 39.27g 3-mercaptopropyltrimethoxysilane, 48.75g dimethyldiethoxysilane, 74.38g methyltrimethoxysilane, 1.62g hexamethyldisiloxane at 50°C under mechanical stirring (According to the thiol content of 0.002mol/g, the ratio of organic group/silicon atom is 1.3) and 175g of toluene, a mixture of 56.2g of deionized water and 3.5g of 36.5% concentrated hydrochloric acid was added dropwise, after 0.5h dripping Continue to react at 50°C for 8h, then wash with water until neutral, and remove the solvent, residual raw materials and low molecular products under reduced pressure at 130mmHg/170°C to obtain 65.5g of colorless and transparent mercapto-containing polysiloxane, marked as silicon Resin 1.

Under mechanical stirring at 50°C, to 58.905g 3-mercaptopropyltrimethoxysilane, 48.75g dimethyldiethoxysilane, 61.18g methyltrimethoxysilane, 1.62g hexamethyldisiloxane (according to A mixture of 56.2g deionized water and 3.5g 36.5% concentrated hydrochloric acid was added dropwise to the mixture of mercapto group content of 0.003mol/g, organic group/silicon atom ratio of 1.3) and 175g of toluene. The reaction was carried out at 50 °C for 8 h, then washed with water until neutral, and the solvent, residual raw materials and low molecular products were removed under reduced pressure at 130 mmHg/170 °C to obtain 38.4 g of colorless and transparent mercapto-containing polysiloxane, marked as silicone resin 2 .

Under mechanical stirring at 50°C, to 78.54g 3-mercaptopropyltrimethoxysilane, 48.75g dimethyldiethoxysilane, 47.98g methyltrimethoxysilane, 1.62g hexamethyldisiloxane (according to The mercapto group content is 0.004mol/g, the ratio of organic group/silicon atom is 1.3) and 175g toluene is added dropwise the mixture of 56.2g deionized water and 3.5g 36.5% concentrated hydrochloric acid. The reaction was carried out at 50 °C for 8 h, then washed with water until neutral, and the solvent, residual raw materials and low molecular weight products were removed under reduced pressure at 130 mmHg/170 °C to obtain 70.5 g of colorless and transparent mercapto-containing polysiloxane, marked as silicone resin 3 .

Under mechanical stirring at 50°C, to 98.18g 3-mercaptopropyltrimethoxysilane, 48.75g dimethyldiethoxysilane, 34.76g methyltrimethoxysilane, 1.62g hexamethyldisiloxane (according to A mixture of 56.2g deionized water and 3.5g 36.5% concentrated hydrochloric acid was added dropwise to the mixture of sulfhydryl content of 0.005mol/g, organic group/silicon atom ratio of 1.3) and 175g of toluene. The reaction was carried out at 50 °C for 8 h, then washed with water until neutral, and the solvent, residual raw materials and low molecular weight products were removed under reduced pressure at 130 mmHg/170 °C to obtain 78.4 g of colorless and transparent mercapto-containing polysiloxane, marked as silicone resin 4 .

Under mechanical stirring at 50°C, to 117.81g 3-mercaptopropyltrimethoxysilane, 48.75g dimethyldiethoxysilane, 34.78g methyltrimethoxysilane, 1.62g hexamethyldisiloxane (according to The mercapto group content is 0.006mol/g, the ratio of organic group/silicon atom is 1.3) and 175g of toluene is added dropwise a mixture of 56.2g of deionized water and 3.5g of 36.5% concentrated hydrochloric acid. The reaction was carried out at 50 °C for 8 h, then washed with water until neutral, and the solvent, residual raw materials and low molecular products were removed under reduced pressure at 130 mmHg/170 °C to obtain 81.5 g of colorless and transparent mercapto-containing polysiloxane, marked as silicone resin 5 .

3) Take 10 g of the acrylate-terminated, silsesquioxane-modified silicone-polyurethane obtained in 1) and the various mercapto-silicon resins obtained in 2), mix them uniformly, and then degas at 130 mmHg/30°C for 20 min. UV curing for 90s, the properties of the obtained materials are shown in Table 2.

Table 2 Influence of mercapto content of mercapto silicone resin

Example 3

1) Add 4g silsesquioxane 3, 50g castor oil, 3g hydroxyl terminated polydimethylsiloxane with molecular weight of 800 and 10g hydroxyl terminated polydimethylsiloxane with molecular weight of 10000 into the clean In a 250mL four-necked flask with a thermometer inserted, the temperature was raised to 100-120°C and decompressed to 130mmHg, dehydrated for 2h and then cooled to 30°C, stirred under nitrogen protection, and added 0.592g of diisobutyltin dilaurate, Then 48.5g MDI was slowly added, then the temperature was raised to 70°C for 6h, 32.456g 4-hydroxyphenyl methacrylate was added, and the reaction was continued for 6h to obtain a yellowish transparent liquid, which was acrylate-terminated, silsesquioxane Alkane-modified silicone-polyurethane.

2) To 78.54g 3-mercaptopropyltrimethoxysilane, 48.75g dimethyldiethoxysilane, 47.98g methyltrimethoxysilane, 1.62g hexamethyldisiloxane at 50°C under mechanical stirring (According to the thiol content of 0.004mol/g, the ratio of organic group/silicon atom is 1.3) and 175g of toluene, a mixture of 56.2g of deionized water and 3.5g of 36.5% concentrated hydrochloric acid was added dropwise, after 0.5h dripping Continue to react at 50°C for 8h, then wash with water until neutral, and remove the solvent, residual raw materials and low molecular products under reduced pressure at 130mmHg/170°C to obtain 70.5g of colorless and transparent mercapto-containing polysiloxane.

3) Take the acrylate-terminated, silsesquioxane-modified silicone-polyurethane obtained in 1) and 1.8 g of the mercapto-silicone resin obtained in 2), mix them uniformly, and then degas at 130 mmHg/30°C for 20 min. After curing for 90s, the properties of the obtained material are shown in Table 3 and Figures 1-3. The decomposition temperature of the obtained UV-cured material at 5% thermal weight loss is higher than 290 °C, and the residual carbon rate at 800 °C is 3.4-15.3%, indicating that the obtained UV-cured material has good thermal stability; the highest tensile strength of the obtained material can reach 10.5MPa, much higher than the pure silicone material without reinforcement.

Table 3 Influence of different molar ratios of acrylate groups to sulfhydryl groups

A material with a molar ratio of acrylate group to mercapto group of 3:1 is used as UV-cured solid wood furniture paint (as shown in Figure 4). After curing, the material has excellent adhesion to solid wood furniture, and the solid wood furniture has a clear texture and a flat layout. This indicates that the obtained UV-curable material has a good use in UV-cured solid wood furniture paint.

In addition, it should be understood that after reading the above description of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Claims (9)

1. A preparation method of a UV-cured high-transparency POSS modified organic silicon-castor oil polyurethane material is characterized by comprising the following steps:

(1) mixing hydroxyl silsesquioxane, amino-terminated/hydroxyl-terminated polysiloxane and castor oil, heating to 100-120 ℃, decompressing, dehydrating, cooling to 30-60 ℃, adding diisobutyl tin laurate under the protection of inert atmosphere, dropwise adding diisocyanate into the mixture under mechanical stirring, reacting to obtain an isocyanate-terminated polyurethane prepolymer, then adding hydroxyl acrylate into the obtained prepolymer at 20-80 ℃, and obtaining acrylate-terminated silsesquioxane-modified organosilicon-polyurethane after the reaction is finished;

the diisocyanate is one or a mixture of more of 2, 4-toluene diisocyanate and 2, 6-toluene diisocyanate isomer mixture, diphenylmethane diisocyanate, 1, 6-hexamethylene diisocyanate and isophorone diisocyanate;

the addition amount of the castor oil accounts for 30-40 wt% of the total mass of the raw materials for preparing the acrylate-terminated silsesquioxane-modified organosilicon-polyurethane;

the hydroxyl silsesquioxane has a structure shown as the following formula (III):

(2) carrying out cohydrolysis-condensation reaction on mercaptopropyl alkoxysilane, difunctional alkoxysilane and trifunctional alkoxysilane in an organic solvent at the temperature of 30-80 ℃ for 0.5-12 h under the catalysis of an acid catalyst, washing with water to neutrality, reducing the pressure at 130mmHg/170 ℃ to 5min, and obtaining clear and transparent polysiloxane containing mercaptopropyl siloxane chain links;

the mercaptopropyl alkoxysilane is one or a mixture of more of mercaptopropyl methyldimethoxysilane, mercaptopropyl methyldiethoxysilane, mercaptopropyl trimethoxysilane and mercaptopropyl triethoxysilane;

the difunctional alkoxy silane is one or a mixture of dimethyl dimethoxy silane, dimethyl diethoxy silane, methyl phenyl dimethoxy silane, methyl phenyl diethoxy silane, diphenyl dimethoxy silane and diphenyl diethoxy silane;

the trifunctional alkoxy silane is one or a mixture of more of methyltrimethoxy silane, methyltriethoxy silane, phenyl trimethoxy silane and phenyl triethoxy silane;

the organic solvent is one or a mixture of more of toluene, xylene, petroleum ether, tetrahydrofuran and butyl acetate, and the dosage of the organic solvent is 0.5-4 times of the total mass of the mercaptopropyl alkoxysilane, the difunctional alkoxysilane and the trifunctional alkoxysilane;

the acid catalyst is one or a mixture of more of hydrochloric acid, sulfuric acid, trifluoromethanesulfonic acid and p-toluenesulfonic acid, and the dosage of the acid catalyst is 0.05-5 wt% of the total mass of the mercaptopropyl alkoxysilane, the difunctional alkoxysilane and the trifunctional alkoxysilane; the acid catalyst is added in the form of aqueous solution, wherein the amount of water is 1-2.5 times of the sum of the mole numbers of alkoxy groups of the mercaptopropylalkoxysilane, the difunctional alkoxysilane and the trifunctional alkoxysilane;

the ratio of the mole number of the mercaptopropylalkoxysilane to the sum of the mole numbers of other alkoxysilanes is 0.05-0.65: 1, and the mole ratio R/Si of all organic groups in the mercaptopropylalkoxysilane, the difunctional alkoxysilane and the trifunctional alkoxysilane to silicon atoms is 1.3-2.0: 1;

(3) uniformly mixing the acrylate-terminated silsesquioxane-modified organosilicon-polyurethane obtained in the step (1) and the polysiloxane containing mercaptopropyl siloxane chain links obtained in the step (2) according to the molar ratio of acrylate groups to mercapto groups of 3:1, then carrying out vacuum degassing on the mixture for 5-30 min at the temperature of 130 mmHg/25-40 ℃, and carrying out UV curing for 10-120 s to obtain the UV-cured high-transparency POSS-modified organosilicon-castor oil polyurethane material;

the UV-cured high-transparency POSS modified organic silicon-castor oil polyurethane material has the light transmittance of 95 percent, the hardness of 3H-9H, the tensile strength of 0.5-10.5 MPa, the initial thermal decomposition temperature of 250-290 ℃, the water absorption rate of not more than 2.80wt percent and the water contact angle of 105.0-109.8 degrees in the light wavelength range of 400-800 nm.

2. The method according to claim 1, wherein in the step (1), the amino-terminated/hydroxy-terminated polysiloxane is one or more of dimethylpolysiloxane having amino groups at both ends, methylphenylpolysiloxane having amino groups at both ends, dimethylpolysiloxane having hydroxy groups at both ends, and methylphenylpolysiloxane having hydroxy groups at both ends.

3. The method according to claim 1, wherein the amino-terminated/hydroxy-terminated polysiloxane in step (1) has a molecular weight of 800 to 15000.

4. The method according to claim 1, wherein in the step (1), the mass of the hydroxyl silsesquioxane is 0.5 to 20% of the mass of the amino terminated/hydroxyl terminated polysiloxane.

5. The method according to claim 1, wherein in the step (1), the diisobutyl tin laurate is added in an amount of 0.1 to 0.4 wt% based on the total mass of the raw materials for preparing the acrylate-terminated silsesquioxane-modified silicone-polyurethane.

6. The method according to claim 1, wherein in the step (1), the diisocyanate is added in a molar ratio of isocyanate groups to the sum of the molar ratios of all amino groups and hydroxyl groups in the hydroxyl silsesquioxane, the amino-terminated/hydroxyl-terminated polysiloxane, and the castor oil, which is 1.05 to 3.5 times.

7. The preparation method according to claim 1, wherein in the step (1), the hydroxy acrylate is one or a mixture of more of hydroxyethyl methacrylate, hydroxypropyl methacrylate, 4-hydroxyphenyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate and 4-hydroxybutyl acrylate;

the hydroxyl acrylate is added in a molar amount equal to the molar amount of isocyanate groups of the prepolymer when no hydroxyl acrylate is added.

8. The UV-cured high-transparency POSS modified organosilicon-castor oil polyurethane material prepared by the preparation method according to any one of claims 1-7.

9. The use of the UV-curable high-transparency POSS modified silicone-castor oil polyurethane material according to claim 8 in the manufacture of UV-curable environment-friendly solid wood furniture paint and flexible electronic devices.

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