Preparation method and application of low-surface-energy corrosion-resistant polyurethane self-lubricating material

Abstract

The invention discloses a preparation method and application of a low-surface-energy corrosion-resistant polyurethane self-lubricating material. The preparation method comprises the following steps: mixing polyether polyol, single-ended dihydroxyl polydimethylsiloxane and diisocyanate, and adding a catalyst; adding a cross-linking agent and heating; adding a chain extender and heating; cooling, adding a chain extender, and heating; cooling to room temperature, and adding triethylamine; adding deionized water and stirring to obtain a white polymer; and mixing the white polymer with a post-crosslinking agent to obtain the low-surface-energy corrosion-resistant polyurethane self-lubricating material. According to the low-surface-energy corrosion-resistant polymer lubricating coating obtained by curing the low-surface-energy corrosion-resistant polyurethane self-lubricating material, the water contact angle of the coating is remarkably increased, the surface energy of the coating is reduced, the adhesive wear is reduced, and the friction coefficient and the wear rate are reduced. And a double-crosslinking structure in the coating plays a role in shielding a corrosive medium, and the corrosion resistance of the coating is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of polymer self-lubricating composite materials, and more particularly, relates to a preparation method and application of a low-surface-energy corrosion-resistant polyurethane self-lubricating material. BACKGROUND

[0002] With the rapid economic development, the per capita automobile ownership in China is showing a steady upward trend. In the automobile industry, a large amount of ethylene-propylene-diene rubber is used in the sealing rubber strip of the vehicle window and the rubber strip of the windshield wiper. The rubber strip of the windshield wiper will be worn due to friction with the vehicle glass during use, which not only shortens the service life of the rubber strip, but also causes the performance of the windshield wiper to decrease, thereby affecting the driving safety. Traditional rubber strip protection methods, such as physical modification of rubber or processing patterns on the surface of rubber, have problems such as complex process, inability to achieve local processing, and insufficient durability.

[0003] Waterborne polyurethane is a polymer elastomer with strong designability and good adhesion, and has certain shape adaptability, and is suitable for use as a rubber strip protection coating. However, the traditional waterborne polyurethane resin coating also faces some challenges during service, such as a high content of polar groups in the molecular structure, a low content of hard segments, and difficult-to-compete abrasion resistance with traditional solvent-based polyurethane, which seriously affects the service life of the coating. Therefore, it is of great significance to modify the waterborne polyurethane, develop an environmentally friendly solid lubricating coating with excellent tribological properties, chemical resistance and antifouling properties, to prolong the service life of the rubber strip of the windshield wiper and improve its performance. SUMMARY

[0004] An object of the present application is to solve at least the above problems and / or deficiencies, and to provide at least the advantages described hereinafter.

[0005] In order to achieve these objects and other advantages according to the present application, a low-surface-energy corrosion-resistant polyurethane self-lubricating material is provided. The low-surface-energy corrosion-resistant polyurethane self-lubricating material is mechanically stirred with titanium ester coupling agent modified dealkalized lignin, and is fully mixed to obtain a mixed solution. The mixed solution is sprayed onto the surface of a substrate, and a low-surface-energy corrosion-resistant polymer lubricating coating is obtained after high-temperature curing. The titanium ester coupling agent modified dealkalized lignin accounts for 1-10wt% of the mass of the mixed solution.

[0006] Preferably, the low-surface-energy corrosion-resistant polyurethane self-lubricating material is applied to be sprayed onto the surface of a substrate, and a low-surface-energy corrosion-resistant polymer lubricating coating is obtained after curing. The specific method comprises: fully mixing the low-surface-energy corrosion-resistant polyurethane self-lubricating material with a solid filler in mechanical stirring to obtain a mixed solution, spraying the mixed solution onto the surface of a treated substrate, and obtaining a low-surface-energy corrosion-resistant polymer lubricating coating after high-temperature curing. The titanate coupling agent modified dealkalized lignin is replaced by one or a combination of several of the following: silicone microspheres, carbon black, dealkalized lignin, colloidal silica; The spraying pressure is 0.2-0.6 MPa, the distance between the spray gun nozzle and the substrate surface is 20-40 cm, and the reciprocating is 6-8 times; the high-temperature curing temperature is 75-85℃, and the curing time is 6-18 h; the thickness of the low-surface-energy corrosion-resistant polymer lubricating coating is 5-50 microns.

[0007] Preferably, the preparation method of the titanate coupling agent modified dealkalized lignin comprises: S1, dispersing dealkalized lignin in N,N-dimethylformamide to obtain a suspension; heating the suspension to 80-90℃, adding isopropyl tri(dioctyl phosphoric acid acyl oxygen) titanate, and reacting under a nitrogen atmosphere for 4-8 h to obtain a reaction liquid after cooling to room temperature; S2, transferring the reaction liquid into a high-pressure reaction kettle, adding stearic acid, and reacting at 120-150℃ for 8-12 h; after cooling to room temperature, vacuum drying the precipitate at 60-80℃ to constant weight to obtain the titanate coupling agent modified dealkalized lignin.

[0008] Preferably, in S1, the amount ratio of dealkalized lignin to N,N-dimethylformamide is 1-10 g:100-150 mL; the mass of isopropyl tri(dioctyl phosphoric acid acyl oxygen) titanate is 1%-10% of the mass of dealkalized lignin; In S2, the amount of stearic acid is 1%-5% of the mass of dealkalized lignin.

[0009] A preparation method of a low-surface-energy corrosion-resistant polyurethane self-lubricating material, comprising the following steps: Step one, mixing polyether polyol, single-end dihydroxy polydimethylsiloxane, and diisocyanate and adding a catalyst, and reacting under a nitrogen atmosphere; Step two, adding a crosslinking agent dissolved in an organic solvent to the reaction system, heating and reacting; adding a chain extender and heating and reacting; Step three, cooling the system, adding a chain extender again, heating and reacting, and completely reacting the remaining NCO groups; turning off the heating and cooling to room temperature, and adding triethylamine to neutralize the carboxyl groups; Step four, adding deionized water, stirring vigorously, and completely emulsifying to obtain a white polymer; mixing the white polymer with a post-crosslinking agent under mechanical stirring to obtain a low-surface-energy corrosion-resistant polyurethane self-lubricating material.

[0010] Preferably, wherein, in step one, the polyether polyol is selected from polytetrahydrofuran, polyethylene glycol, polypropylene glycol, and the like, or a combination of several thereof; the amount of polyether polyol is 60-70wt% of the total mass of polyether polyol, mono-terminated dihydroxy polydimethylsiloxane, and diisocyanate.

[0011] Preferably, wherein, in step one, the molecular weight of mono-terminated dihydroxy polydimethylsiloxane is 4000-5000; the amount of mono-terminated dihydroxy polydimethylsiloxane is 0-10wt% of the total mass of polyether polyol, mono-terminated dihydroxy polydimethylsiloxane, and diisocyanate.

[0012] Preferably, wherein, in step one, the diisocyanate is selected from isophorone diisocyanate, p-phenylene diisocyanate, toluene 2,6 diisocyanate, hexamethylene diisocyanate, and the like, or a combination of several thereof; the amount of diisocyanate is 20-30wt% of the total mass of polyether polyol, mono-terminated dihydroxy polydimethylsiloxane, and diisocyanate.

[0013] Preferably, wherein, in step one, the catalyst includes one or more of dibutyl tin dilaurate, zinc isooctoate, or bismuth isooctoate; the amount of catalyst is 1%-5% of the mass of polyether polyol, mono-terminated dihydroxy polydimethylsiloxane, and diisocyanate. In step two, the organic solvent is a combination of one or several of N,N-dimethylformamide, ethanol, xylene, petroleum ether, ethyl acetate, butyl acetate, and N-methyl pyrrolidone. The crosslinking agent is selected from trimethylolpropane, dicumyl peroxide, formaldehyde, sulfur, and the like, or a combination of several thereof; the amount of crosslinking agent is 1%-5% of the mass of polyether polyol, mono-terminated dihydroxy polydimethylsiloxane, and diisocyanate. In steps two and three, the chain extender is selected from 2,2-dimethylol propionic acid, 1,4-butanediol, ethylene glycol, neopentyl glycol, and propylene glycol, or a combination of several thereof. In step two, the amount of chain extender is 1%-5% of the mass of polyether polyol, mono-terminated dihydroxy polydimethylsiloxane, and diisocyanate. In step three, the amount of chain extender is 1%-5% of the mass of polyether polyol, mono-terminated dihydroxy polydimethylsiloxane, and diisocyanate.

[0014] Preferably, wherein, in step four, the post-crosslinking agent includes one or a combination of several of aziridine, polycarbodiimide, hexamethylene diisocyanate isocyanurate trimer; the amount of post-crosslinking agent is 0.1%-5% of the mass of polyether polyol, mono-terminated dihydroxy polydimethylsiloxane, and diisocyanate. The amount of deionized water is 2-3 times of the mass of the polyether polyol, the mono-end dihydroxy polydimethylsiloxane and the diisocyanate, so that the solid content is 25%-33%; The reaction temperature in the step one is 25-35 DEG C, and the reaction time is 30-50 min; In the step two, the temperature rising includes first rising 35-45 DEG C, reacting 20-40 min, then rising to 45-55 DEG C and reacting 0.5-1.5 h; the temperature rising after adding the chain extender is 65-75 DEG C, and the reaction time is 1.5-2.5 h; In the step three, the cooling temperature is 45-55 DEG C; In the step four, the rotating speed of the mechanical stirring is 150-250 rpm, and the stirring time is 6-18 h.

[0015] The application at least has the following beneficial effects: The prepared corrosion-resistant polyurethane self-lubricating coating with low surface energy has PDMS on the surface, significantly increases the water contact angle of the coating, reduces the surface energy of the coating, reduces the adhesive wear in the friction process, and reduces the friction coefficient and the wear rate. In addition, the double cross-linking structure in the coating can shield the corrosion medium well, thereby improving the corrosion resistance of the coating. The application of the coating on the surface of the automobile sealing strip can significantly reduce the friction coefficient and the wear rate, and enhance the corrosion resistance.

[0016] The PDMS involved in the application is the main reason for reducing the surface energy of the coating. The reduction of the surface energy can reduce the friction shear force and adhesive force between the coating and the counter material. The double cross-linking structure improves the wear resistance and corrosion resistance of the coating. The addition of the solid filler further improves the friction-reducing and wear-resistant performance of the coating.

[0017] The low-surface-energy corrosion-resistant polyurethane self-lubricating material has excellent properties such as wear resistance, good dispersibility, corrosion resistance, low friction coefficient and high ductility, and can improve the service life and stability of the rubber sealing element.

[0018] The alkaline lignin molecule structure contains rich benzene rings, and the layered arrangement itself has a certain friction reduction potential. However, the unmodified lignin is easy to agglomerate and has poor compatibility with hydrophobic polyurethane due to the large number of hydroxyl groups contained therein, so the lubricating potential cannot be exerted. In the prior art, silane coupling agents are usually used to modify lignin to improve the surface friction coefficient of lignin. However, the application uses long-chain isopropyl tri(dioctyl phosphoric acid acyloxy) titanate (C 51 H 109 O 13 P3Ti) and stearic acid (C 18 H 36O2) is a long chain fatty acid with 18 carbons, at the same time it has excellent lubrication modification effect, the synergistic modification of titanate coupling agent and stearic acid not only solves the dispersibility and surface hydrophobicity of the dealkalized lignin, but also the stearic acid is secondarily modified on this basis, introduces more dense and longer lubricating chain, the results show that the friction coefficient of the coating can be significantly reduced by adding the dealkalized lignin modified by the above-mentioned modification. 51 H 109 O 13 P3Ti) and stearic acid (C 18 H 36 O2) has a long chain structure, the dealkalized lignin powder is coated, not only the dispersibility of the dealkalized lignin powder is improved, but also the compatibility between the dealkalized lignin and the low surface energy corrosion-resistant polyurethane self-lubricating material is improved, the surface of the unmodified dealkalized lignin is rich in polar hydroxyl (-OH), which is hydrophilic. And the polyurethane matrix (especially after introducing the PDMS segment) is hydrophobic. The mismatch of such polarity will cause the lignin to agglomerate in the polyurethane, forming stress defect points, which will increase the friction and even cause wear. The one end of the titanate coupling agent (isopropyl tri (dioctyl phosphoric acyloxy) titanate) molecule forms a firm chemical bond (Ti-O-C) with the hydroxyl group on the surface of the lignin, so the modification of the titanate coupling agent is used first to change the surface properties of the dealkalized lignin, making it change from hydrophilic to hydrophobic, greatly improving the compatibility with the polyurethane matrix, ensuring that the modified lignin can be uniformly and stably dispersed in the matrix at the nanometer / micron scale, reducing the agglomeration of the dealkalized lignin. Stearic acid (C 18 H 36 O2) is a long chain fatty acid with 18 carbons, at the same time it has excellent lubrication modification effect, the synergistic modification of titanate coupling agent and stearic acid not only solves the dispersibility and surface hydrophobicity of the dealkalized lignin, but also the stearic acid is secondarily modified on this basis, introduces more dense and longer lubricating chain, the results show that the friction coefficient of the coating can be significantly reduced by adding the dealkalized lignin modified by the above-mentioned modification.

[0019] Other advantages, objects, and features of the present application will be apparent to those skilled in the art from the following specification. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 Synthesis path of waterborne polyurethane Figure 2 Chemical resistance test of example 1, comparative example 5 and EPDM rubber; Figure 3 Water contact angle and surface energy of the coatings obtained from example 1, example 2 and comparative examples 1-3. DETAILED DESCRIPTION

[0021] The application will be further described in detail below with reference to the drawings, so that those skilled in the art can implement the application according to the description.

[0022] It should be understood that the terms such as "have", "contain" and "include" used herein do not exclude the presence or addition of one or more other elements or combinations thereof. Example 1 As Figure 1 shown, a preparation method of a low surface energy corrosion-resistant polyurethane self-lubricating material includes the following steps: Step one, put polytetrahydrofuran (PTMEG), 2,2-dimethylol propionic acid (DMPA) and single-end dihydroxy polydimethylsiloxane (PDMS) into a 80℃ vacuum oven for 12h to remove water. Filter N,N-dimethylformamide (DMF) through 4A molecular sieve for 12h.

[0023] Step two, introduce 10.13g PTMEG, 0.53g PDMS, 5g isophorone diisocyanate (IPDI) and 0.5g dibutyltin dilaurate into a four-necked flask equipped with a condenser and a stirrer and react at 30℃ for 40min under nitrogen environment.

[0024] Step three, add 10ml DMF dissolved 0.4g trimethylolpropane (TMP), and react at 40℃ for 30min.

[0025] Step four, react at 50℃ for 1h, then add 0.72g DMPA as chain extender to the solution and react at 70℃ for 2.5h.

[0026] Step five, cool the system to 50℃, and add 0.68g 1,4-butanediol (BDO) and react for 1h.

[0027] Step six, turn off the heating and cool to room temperature, add 0.68g triethylamine (TEA) to neutralize the carboxyl group, and react for 1h.

[0028] Step seven, add deionized water to make the solid content reach 30%, stir at 1200rpm for 3h to make it completely emulsified, and obtain a white polymer.

[0029] Step eight, take out 10g of the white polymer and mix with 0.03g of polycarbodiimide (PCD) under mechanical stirring to obtain a low surface energy corrosion-resistant polyurethane self-lubricating material.

[0030] Example 2 A preparation method of a low surface energy corrosion-resistant polyurethane self-lubricating material. Including the following steps: Step one, put polytetrahydrofuran (PTMEG), 2,2-dimethylol propionic acid (DMPA) and monohydroxy polydimethylsiloxane (PDMS) into 80℃ vacuum oven for 12h to remove water. Filter N,N-dimethylformamide (DMF) through 4A molecular sieve for 12h.

[0031] Step two, introduce 10.13g PTMEG, 0.53g PDMS, 0.5g dibutyltin dilaurate and 5g isophorone diisocyanate (IPDI) into a four-necked flask equipped with a condenser, a stirrer and react at 30℃ for 40min under nitrogen environment.

[0032] Step three, add 0.4g trimethylolpropane (TMP) dissolved in 10ml DMF, and react at 40℃ for 30min.

[0033] Step four, react at 50℃ for 1h, add 0.72g DMPA as chain extender to the solution and react at 70℃ for 2.5h.

[0034] Step five, cool the system to 50℃, and add 0.68g 1,4-butanediol (BDO) and react for 1h.

[0035] Step six, turn off the heating and cool to room temperature, add 0.68g triethylamine to neutralize the carboxyl group and react for 1h.

[0036] Step seven, add deionized water to make the solid content reach 30%, stir at 1200rpm for 3h to make it fully emulsified, and obtain a white polymer.

[0037] Step eight, mix 10g white polymer with 0.03g polycarbodiimide under mechanical stirring to obtain a low surface energy corrosion-resistant polyurethane self-lubricating material.

[0038] Mix 0.2g dealkalized lignin with 9.8g low surface energy corrosion-resistant polyurethane self-lubricating material under mechanical stirring to obtain a composite material solution.

[0039] Example 3 A method for preparing a low surface energy corrosion-resistant polyurethane self-lubricating material. It comprises the following steps: Step one, put polytetrahydrofuran (PTMEG), 2,2-dimethylol propionic acid (DMPA) and monohydroxy polydimethylsiloxane (PDMS) into 80℃ vacuum oven for 12h to remove water. Filter N,N-dimethylformamide (DMF) through 4A molecular sieve for 12h.

[0040] Step two, 10.13g PTMEG, 0.53g PDMS, 5g isophorone diisocyanate (IPDI) and 0.5g dibutyl tin dilaurate were introduced into a four-necked flask equipped with a condenser, a stirrer and reacted at 30℃ for 40min under nitrogen atmosphere.

[0041] Step three, 10ml 0.4g trimethylolpropane (TMP) dissolved in DMF was added and the temperature was raised to 40℃ for 30min.

[0042] Step four, the temperature was raised to 50℃ for 1h, and then 0.72g DMPA was added as a chain extender and the temperature was raised to 70℃ for 2.5h.

[0043] Step five, the system was cooled to 50℃, and 0.68g 1,4-butanediol (BDO) was added and reacted for 1h.

[0044] Step six, the heating was turned off and the temperature was cooled to room temperature, 0.68g triethylamine (TEA) was added to neutralize the carboxyl group and reacted for 1h.

[0045] Step seven, deionized water was added to make the solid content reach 30%, and stirred at 1200rpm for 3h to make it fully emulsified, and a white polymer was obtained.

[0046] Step eight, 10g of the white polymer was taken out and mixed with 0.03g polycarbodiimide (PCD) under mechanical stirring to obtain a low surface energy corrosion-resistant polyurethane self-lubricating material.

[0047] 9.8g of the low surface energy corrosion-resistant polyurethane self-lubricating material was mechanically stirred with 0.2g of titanium ester coupling agent modified dealkalized lignin to obtain a mixed solution; The preparation method of the titanium ester coupling agent modified dealkalized lignin comprises: S1, 10g of dealkalized lignin was dispersed in 150ml of N,N-dimethylformamide to obtain a suspension; the suspension was heated to 80℃, 0.5g of isopropyl tri(dioctyl phosphoric acid acyl oxygen) titanate was added, and reacted at 80℃ for 6h under nitrogen atmosphere, and then cooled to room temperature to obtain a reaction liquid; S2, the reaction liquid was transferred into a high-pressure reaction kettle, 0.25g of stearic acid was added, and reacted at 150℃ for 12h, and then cooled to room temperature; the precipitate was vacuum dried at 60℃ until the weight was constant to obtain the titanium ester coupling agent modified dealkalized lignin.

[0048] Example 4 A preparation method of a low surface energy corrosion-resistant polyurethane self-lubricating material comprises the following steps: Step one, put polytetrahydrofuran (PTMEG), 2,2-dimethylol propionic acid (DMPA) and monohydroxy polydimethylsiloxane (PDMS) into a vacuum oven at 80℃ for 12h to remove water. Filter N,N-dimethylformamide (DMF) through 4A molecular sieve for 12h.

[0049] Step two, introduce 10.13g PTMEG, 0.53g PDMS, 5g isophorone diisocyanate (IPDI) and 0.5g dibutyltin dilaurate into a four-necked flask equipped with a condenser and a stirrer and react at 30℃ for 40min under nitrogen atmosphere.

[0050] Step three, add 10ml DMF dissolved 0.4g trimethylolpropane (TMP), and warm up to 40℃ for 30min.

[0051] Step four, warm up to 50℃ for 1h, and then add 0.72g DMPA as a chain extender and warm up to 70℃ for 2.5h.

[0052] Step five, cool down the system to 50℃, and add 0.68g 1,4-butanediol (BDO) and react for 1h.

[0053] Step six, turn off the heating and cool down to room temperature, add 0.68g triethylamine (TEA) to neutralize the carboxyl group, and react for 1h.

[0054] Step seven, add deionized water to make the solid content reach 30%, stir at 1200rpm for 3h to make it fully emulsified, and obtain a white polymer.

[0055] Step eight, take out 10g of the white polymer and mix with 0.03g polymeric carbodiimide (PCD) under mechanical stirring to obtain a low-surface-energy corrosion-resistant polyurethane self-lubricating material.

[0056] Mechanically stir 9.8g of the low-surface-energy corrosion-resistant polyurethane self-lubricating material with 0.2g of titanium ester coupling agent modified dealkalized lignin to obtain a mixed solution; The preparation method of the titanium ester coupling agent modified dealkalized lignin comprises: S1, disperse 10g of dealkalized lignin in 150ml of N,N-dimethylformamide to obtain a suspension; warm up the suspension to 80℃, add 1g of isopropyl tri(dioctyl phosphoric acid acyloxy) titanate, and react under nitrogen atmosphere for 6h to obtain a reaction liquid after cooling to room temperature; S2, transfer the reaction liquid into a high-pressure reaction kettle, add 0.5g of stearic acid, and react at 150℃ for 12h; after cooling to room temperature, vacuum dry the precipitate at 60℃ to a constant weight to obtain the titanium ester coupling agent modified dealkalized lignin.

[0057] Comparative Example 1 Step one, 10.36g of polytetramethylene ether glycol (PTMEG), 0.72g of 2,2-dimethylol propionic acid (DMPA) were put into a vacuum oven at 80°C for 12h to remove water. DMF was filtered through 4A molecular sieve for 12h.

[0058] Step two, 10.36g of PTMEG, 0.5g of dibutyltin dilaurate and 5g of isophorone diisocyanate (IPDI) were introduced into a four-necked flask equipped with a condenser, a stirrer and reacted at 30°C for 40min under nitrogen.

[0059] Step three, 0.4g of trimethylolpropane (TMP) dissolved in 10ml of DMF was added and the temperature was raised to 40°C for 30min.

[0060] Step four, the temperature was raised to 50°C for 1h, 0.72g of DMPA was added to the solution and the temperature was raised to 70°C for 2.5h.

[0061] Step five, the system was cooled to 50°C and 0.68g of 1,4-butanediol (BDO) was added and reacted for 1h.

[0062] Step six, the heating was turned off and the temperature was cooled to room temperature, 0.68g of triethylamine was added to neutralize the carboxyl group and reacted for 1h.

[0063] Step seven, deionized water was added to make the solid content reach 30%, stirred at 1200rpm for 3h to make it fully emulsified, and a white polymer was obtained.

[0064] Step eight, 10g of the white polymer was mixed with 0.03g of polymeric carbodiimide under mechanical stirring to obtain a low-surface-energy corrosion-resistant polyurethane self-lubricating material.

[0065] 0.5g of aqueous carbon black (CB) was mixed with 9.5g of low-surface-energy corrosion-resistant polyurethane self-lubricating material under mechanical stirring to obtain a composite material solution.

[0066] Comparative Example 2 Step one, polytetramethylene ether glycol (PTMEG), 2,2-dimethylol propionic acid (DMPA) were put into a vacuum oven at 80°C for 12h to remove water. DMF was filtered through 4A molecular sieve for 12h.

[0067] Step two, 10.36g of PTMEG, 0.5g of dibutyltin dilaurate and 5g of isophorone diisocyanate (IPDI) were introduced into a four-necked flask equipped with a condenser, a stirrer and reacted at 30°C for 40min under nitrogen.

[0068] Step three, add 0.4g trimethylolpropane (TMP) dissolved in 10ml DMF, and react for 30min at 40°C.

[0069] Step four, react for 1h at 50°C, add 0.72g DMPA to the solution and react for 2.5h at 70°C.

[0070] Step five, cool the system to 50°C, and add 0.68g 1,4-butanediol (BDO) and react for 1h.

[0071] Step six, turn off the heating and cool to room temperature, add 0.68g triethylamine to neutralize the carboxyl groups and react for 1h.

[0072] Step seven, add deionized water to achieve a solid content of 30%, and stir at 1200rpm for 3h to completely emulsify, obtaining a white polymer.

[0073] Step eight, mix 10g of the white polymer with 0.03g of a polycarbodiimide under mechanical stirring to obtain a low-surface-energy corrosion-resistant polyurethane self-lubricating material.

[0074] Step nine, mix 0.3g of dealkalized lignin (Lig) with 9.7g of the low-surface-energy corrosion-resistant polyurethane self-lubricating material under mechanical stirring to obtain a composite material solution.

[0075] Comparative Example 3 Step one, place polytetrahydrofuran (PTMEG), 2,2-dimethylol propionic acid (DMPA), and monohydroxyl polydimethylsiloxane (PDMS) in a vacuum oven at 80°C for 12h to remove water. Filter the DMF through 4A molecular sieves for 12h.

[0076] Step two, introduce 10.05g of PTMEG, 0.71g of PDMS, 0.5g of dibutyltin dilaurate, and 5g of isophorone diisocyanate (IPDI) into a four-necked flask equipped with a condenser and a stirrer, and react for 40min at 30°C under a nitrogen atmosphere.

[0077] Step three, add 1g of trimethylolpropane (TMP) dissolved in 10ml DMF, and react for 30min at 40°C.

[0078] Step four, react for 1h at 50°C. Add 0.68g of DMPA to the solution and react for 2.5h at 70°C.

[0079] Step five, cool the system to 50°C, and add 0.72g of 1,4-butanediol (BDO) and react for 1h.

[0080] Step six, turn off the heating and cool to room temperature, add 0.68g triethylamine to neutralize the carboxyl group and react for 1h.

[0081] Step seven, add deionized water to make the solid content reach 30%, stir at 1200rpm for 3h to make it fully emulsified, and obtain a white polymer.

[0082] Step eight, mix 10g of the white polymer with 0.03g of the polymeric carbodiimide under mechanical stirring to obtain an aqueous polyurethane.

[0083] Step nine, mix 0.2g of the silicone microspheres (Si) with 9.8g of the aqueous polyurethane under mechanical stirring to obtain a composite solution.

[0084] Comparative Example 4 Step one, place the polytetramethylene ether glycol (PTMEG) and 2,2-dimethylol propionic acid (DMPA) in a vacuum oven at 80°C for 12h to remove water. Filter the DMF through 4A molecular sieves for 12h.

[0085] Step two, introduce 10.26g of PTMEG, 0.5g of dibutyltin dilaurate, and 5g of isophorone diisocyanate (IPDI) into a four-necked flask equipped with a condenser and a stirrer, and react at 30°C for 40min under a nitrogen atmosphere.

[0086] Step three, add 0.6g of trimethylolpropane (TMP) dissolved in 10ml of DMF, and raise the temperature to 40°C and react for 30min.

[0087] Step four, raise the temperature to 50°C and react for 1h. Add 0.88g of DMPA to the solution and raise the temperature to 70°C and react for 2.5h.

[0088] Step five, lower the system temperature to 50°C, and add 0.70g of 1,4-butanediol (BDO) and react for 1h.

[0089] Step six, turn off the heating and cool to room temperature, add 0.68g triethylamine to neutralize the carboxyl group and react for 1h.

[0090] Step seven, add deionized water to make the solid content reach 30%, stir at 1200rpm for 3h to make it fully emulsified, and obtain a white polymer.

[0091] Step eight, mix 10g of the white polymer with 0.03g of the polymeric carbodiimide under mechanical stirring to obtain an aqueous polyurethane.

[0092] Step nine, mix 0.1g of colloidal silica (CB) with 9.9g of the aqueous polyurethane under mechanical stirring to obtain a composite solution.

[0093] Comparative Example 5 A method for preparing a low surface energy corrosion resistant polyurethane self-lubricating material coating. The method comprises the following steps: Step one, put polytetramethylene ether glycol (PTMEG), 2,2-dimethylol propionic acid (DMPA) and 0.53g of monohydroxy polydimethylsiloxane (PDMS) into a 80℃ vacuum oven for 12h to remove water. Filter DMF through 4A molecular sieve for 12h.

[0094] Step two, introduce 10.13g PTMEG, 0.53g PDMS, 5g isophorone diisocyanate (IPDI) and 0.5g dibutyltin dilaurate into a four-necked flask equipped with a condenser and a stirrer and react at 30℃ for 40min under nitrogen environment.

[0095] Step three, add 0.4g trimethylolpropane (TMP) dissolved in 10ml DMF, and react at 40℃ for 30min.

[0096] Step four, increase the temperature to 50℃ and react for 1h. Add 0.72g DMPA to the solution and increase the temperature to 70℃ and react for 2.5h.

[0097] Step five, cool the system to 50℃, and add 0.68g 1,4-butanediol (BDO) and react for 1h.

[0098] Step six, turn off the heating and cool to room temperature, add 0.68g triethylamine to neutralize the carboxyl group and react for 1h.

[0099] Step seven, add deionized water to make the solid content reach 30%, stir at 1200rpm for 3h to make it fully emulsified, and obtain the aqueous polyurethane.

[0100] Comparative example 6 A method for preparing a low surface energy corrosion resistant polyurethane self-lubricating material. The method comprises the following steps: Step one, put polytetramethylene ether glycol (PTMEG), 2,2-dimethylol propionic acid (DMPA) and monohydroxy polydimethylsiloxane (PDMS) into a 80℃ vacuum oven for 12h to remove water. Filter N,N-dimethylformamide (DMF) through 4A molecular sieve for 12h.

[0101] Step two, introduce 10.13g PTMEG, 0.53g PDMS, 5g isophorone diisocyanate (IPDI) and 0.5g dibutyltin dilaurate into a four-necked flask equipped with a condenser and a stirrer and react at 30℃ for 40min under nitrogen environment.

[0102] Step three, add 0.4g trimethylolpropane (TMP) dissolved in 10ml DMF, and react at 40℃ for 30min.

[0103] Step four, temperature is raised to 50℃ for 1h, then 0.72g DMPA is added as chain extender to the solution and temperature is raised to 70℃ for 2.5h.

[0104] Step five, the system is cooled to 50℃, and 0.68g 1,4-butanediol (BDO) is added for 1h.

[0105] Step six, the heating is turned off and cooled to room temperature, 0.68g triethylamine (TEA) is added to neutralize the carboxyl group, and the reaction is carried out for 1h.

[0106] Step seven, deionized water is added to make the solid content reach 30%, and stirring is carried out at 1200rpm for 3h to make it fully emulsified, and a white polymer is obtained.

[0107] Step eight, 10g of the white polymer is taken out and mixed with 0.03g of polycarbodiimide (PCD) under mechanical stirring to obtain a low-surface-energy corrosion-resistant polyurethane self-lubricating material.

[0108] 9.8g of the low-surface-energy corrosion-resistant polyurethane self-lubricating material is mechanically stirred with 0.2g of titanium ester coupling agent modified dealkalized lignin to obtain a mixed solution; The preparation method of the titanium ester coupling agent modified dealkalized lignin comprises the following steps: 10g of dealkalized lignin is dispersed in 150ml of N,N-dimethylformamide to obtain a suspension; the suspension is heated to 80℃, 0.5g of isopropyl tri(dioctyl phosphoric acid acyl oxygen) titanate is added, and the reaction is carried out under a nitrogen atmosphere for 6h; after cooling to room temperature, a reaction liquid is obtained; the precipitate after standing of the reaction liquid is vacuum dried at 60℃ until the weight is constant to obtain the titanium ester coupling agent modified dealkalized lignin.

[0109] Comparative Example 7 A preparation method of a low-surface-energy corrosion-resistant polyurethane self-lubricating material. It comprises the following steps: Step one, polytetramethylene glycol (PTMEG), 2,2-dimethylol propionic acid (DMPA) and monohydroxyl polydimethylsiloxane (PDMS) are placed in a 80℃ vacuum oven for 12h to remove water. N,N-dimethylformamide (DMF) is filtered through 4A molecular sieves for 12h.

[0110] Step two, 10.13g of PTMEG, 0.53g of PDMS, 5g of isophorone diisocyanate (IPDI) and 0.5g of dibutyl tin dilaurate are introduced into a four-necked flask equipped with a condenser, a stirrer and stirred at 30℃ for 40min under a nitrogen atmosphere.

[0111] Step three, 10ml of 0.4g of trimethylolpropane (TMP) dissolved in DMF is added, and the temperature is raised to 40℃ for 30min.

[0112] Step four, temperature is raised to 50℃ for 1h, then 0.72g DMPA is added as chain extender to the solution and temperature is raised to 70℃ for 2.5h.

[0113] Step five, the system is cooled to 50℃, and 0.68g 1,4-butanediol (BDO) is added for 1h.

[0114] Step six, heating is turned off and the temperature is cooled to room temperature, 0.68g triethylamine (TEA) is added to neutralize the carboxyl group, and the reaction is carried out for 1h.

[0115] Step seven, deionized water is added to make the solid content reach 30%, and stirring is carried out at 1200rpm for 3h to make it fully emulsified, and a white polymer is obtained.

[0116] Step eight, 10g of the white polymer is taken out and mixed with 0.03g of polycarbodiimide (PCD) under mechanical stirring to obtain a low-surface-energy corrosion-resistant polyurethane self-lubricating material.

[0117] 9.8g of the low-surface-energy corrosion-resistant polyurethane self-lubricating material is mechanically stirred with 0.2g of stearic acid modified dealkalized lignin to obtain a mixed solution; The preparation method of the stearic acid modified dealkalized lignin comprises the following steps: S1, 10g of dealkalized lignin is dispersed in 150ml of N,N-dimethylformamide to obtain a suspension; S2, the suspension is transferred into a high-pressure reaction kettle, 0.25g of stearic acid is added, and the reaction is carried out at 150℃ for 12h, and after cooling to room temperature, the precipitate is vacuum dried at 60℃ to constant weight to obtain stearic acid modified dealkalized lignin.

[0118] Comparative example 8 A preparation method of a low-surface-energy corrosion-resistant polyurethane self-lubricating material comprises the following steps: Step one, polytetramethylene glycol (PTMEG), 2,2-dimethylol propionic acid (DMPA) and monohydroxyl polydimethylsiloxane (PDMS) are placed in a 80℃ vacuum oven for 12h to remove water. N,N-dimethylformamide (DMF) is filtered through 4A molecular sieve for 12h.

[0119] Step two, 10.13g of PTMEG, 0.53g of PDMS, 5g of isophorone diisocyanate (IPDI) and 0.5g of dibutyltin dilaurate are introduced into a four-necked flask equipped with a condenser, a stirrer and stirred at 30℃ for 40min under nitrogen environment.

[0120] Step three, add 10 ml DMF dissolved 0.4 g trimethylolpropane (TMP), the temperature is raised to 40 DEG C for 30 min.

[0121] Step four, the temperature is raised to 50 DEG C for 1 h, and then 0.72 g DMPA is added to the solution as a chain extender and the temperature is raised to 70 DEG C for 2.5 h.

[0122] Step five, the system is cooled to 50 DEG C, and 0.68 g of 1,4-butanediol (BDO) is added for 1 h.

[0123] Step six, turn off the heating and cool to room temperature, add 0.68 g of triethylamine (TEA) to neutralize the carboxyl group, and react for 1 h.

[0124] Step seven, add deionized water to make the solid content reach 30%, stir at 1200 rpm for 3 h, and fully emulsify to obtain a white polymer.

[0125] Step eight, take out 10 g of the white polymer and mix it with 0.03 g of poly carbodiimide (PCD) under mechanical stirring to obtain a low-surface-energy corrosion-resistant polyurethane self-lubricating material.

[0126] Mechanically stir 9.8 g of the low-surface-energy corrosion-resistant polyurethane self-lubricating material with 0.2 g of silane coupling agent modified dealkalized lignin to obtain a mixed solution; The preparation method of the silane coupling agent modified dealkalized lignin comprises: S1, disperse 10 g of dealkalized lignin in 150 ml of N,N-dimethylformamide to obtain a suspension; heat the suspension to 80 DEG C, add 0.5 g of γ-aminopropyltriethoxysilane, and react under a nitrogen atmosphere for 6 h to obtain a reaction liquid after cooling to room temperature; S2, transfer the reaction liquid into a high-pressure reaction kettle, add 0.25 g of stearic acid, and react at 150 DEG C for 12 h; after cooling to room temperature, the precipitate obtained after standing of the reaction liquid is vacuum dried at 60 DEG C to a constant weight to obtain the silane coupling agent modified dealkalized lignin.

[0127] The low-surface-energy corrosion-resistant polyurethane self-lubricating material, the composite material solution, and the waterborne polyurethane solution obtained in each example and comparative example are sprayed onto treated rubber, and cured in an 80 DEG C oven for 12 h. The cured coating is ultrasonically cleaned with petroleum ether and scrubbed, and the surface energy, tribological properties, and corrosion resistance are measured.

[0128] The tribological properties of the coatings were tested on a high-speed reciprocating friction and wear tester (MFT-R4000, Lanzhou, China). Glass balls with a size of 6 mm were used as the counterpart. The glass balls were cleaned by ultrasonic washing before use. The tribological tests were carried out under dry friction conditions with a constant load of 2 N and 3 N, and a stroke frequency of 0.5 Hz. Each test lasted for 40 min. The friction coefficient was recorded by the force sensor of the machine.

[0129] Table 1 is a table of the friction coefficient data of the examples and comparative examples. As can be seen from Table 1, Example 2 has the lowest friction coefficient, and Comparative Example 5 and Comparative Example 2 prove that an appropriate amount of PDMS can significantly reduce the friction coefficient of the coating. Comparative Example 1 and Comparative Example 5 prove that a double crosslinking structure can effectively reduce the friction coefficient of the coating.

[0130] Table 1 is a table of the friction coefficient data of the examples and comparative examples. As can be seen from Table 1, Example 2 has the lowest friction coefficient, and Comparative Example 5 and Comparative Example 2 prove that an appropriate amount of PDMS can significantly reduce the friction coefficient of the coating. Comparative Example 1 and Comparative Example 5 prove that a double crosslinking structure can effectively reduce the friction coefficient of the coating. As can be seen from the above table, the friction coefficient of the coating obtained by adding the titanium ester coupling agent modified dealkalized lignin in Example 3 and Example 4 is further reduced, indicating that the dealkalized lignin modified by the titanium ester coupling agent and stearic acid can effectively reduce the friction coefficient of the polymer lubricating coating.

[0131] The chemical resistance of the coating was analyzed by exposing the surface to 0.1 mol / L HCl, NaOH and acetone for 12 hours, respectively, by observing the corrosion of the coating surface.

[0132] Figure 2 is the chemical resistance test of Example 1, Comparative Example 5 and EPDM rubber, and it is found that the bare EPDM is severely corroded by HCl, NaOH and acetone, respectively. Moreover, the corrosion area exposed to HCl is larger than that exposed to NaOH and acetone, as shown by the red circles. This is because the hydrogen and chloride ions in hydrochloric acid can react with EPDM, causing the molecular chain to break. For the rubber sprayed with Comparative Example 5, there is almost no corrosion area after exposure to HCl, and there is only a slight corrosion trace after exposure to NaOH. However, after exposure to acetone, the corrosion area on the surface of the coating is very large. This is because acetone is a good solvent for polyurethane, and the penetration of the solution into the molecular chain will cause the polyurethane molecular chain to swell, and the part of the molecular chain with low crosslinking degree is dissolved. Example 1 shows the best chemical resistance to HCl, NaOH and acetone, respectively. The above results prove that the chemical inertness of PDMS and the high crosslinking degree of the coating can protect the substrate from corrosion by acids, bases and organic solvents, respectively, and the introduction of PDMS will help to avoid the contact of the coating with corrosive substances such as acids, bases and organic solvents, and the improvement of the crosslinking degree of the polymer molecules will help to reduce the penetration of the corrosive substances into the coating, both of which are conducive to the improvement of the chemical resistance of the coating.

[0133] A method for testing the water contact angle and surface energy of the prepared coating of the examples and comparative examples, comprising: The contact angle (CA) of water and diiodomethane on the waterborne polyurethane-based coating was measured using an optical contact angle tester (DECCA-100, DECCA, China), on the basis of which the surface energy of the coating was calculated according to the following Fowkes equation: wherein, represents the surface energy of the solid surface, represents the energy of the dispersive force, represents the energy of the polar force. θ represents the contact angle. The , , total surface tension of the liquid, the dispersive component of the surface tension of the liquid, the polar component of the surface tension of the liquid, respectively, , , are 72.8 mN / m, 21.8 mN / m and 51.0 mN / m, respectively, and the , , of diiodomethane are 50.8 mN / m, 50.8 mN / m and 0 mN / m, respectively.

[0134] In order to test the wetting performance of the coating, the contact angle of the coating with deionized water and diiodomethane was measured and the surface energy of the coating was calculated, and the contact angle of the pure waterborne polyurethane (WPU) coating was 66.3°. Due to the low polarity of the PDMS segment, the introduction of PDMS into the WPU molecular chain for modification can improve the hydrophobicity of the material. When the content of PDMS reaches 3wt%, the coating becomes hydrophobic. Correspondingly, the pure WPU coating has the highest surface energy of 40.7 mN / m, and the introduction of PDMS effectively reduces the surface energy of WPU-PDMSx. When the content of PDMS is 4wt%, the surface energy of the WPU-PDMS4 coating is reduced to 27.65 mN / m. Due to the reduction in the number of polar groups carboxyl in the WPU molecule, the establishment of the crosslinked network also helps to reduce the penetration of water molecules into the interior of the coating, improve the hydrophobicity of the coating, and further reduce the surface energy of the coating.

[0135] The number of devices and the scale of processing described herein are used to simplify the explanation of the present application. Applications, modifications and variations of the present application will be apparent to those skilled in the art.

[0136] While embodiments of the application have been disclosed in connection with the above specification and drawings this description is not intended to limit the scope of the application and many modifications, enhancements, alternatives, and variations will become apparent to those skilled in the art from this disclosure. Accordingly, it is expressly intended that the description should not limit the application as claimed but rather the only limitation placed on the scope of the application be the scope of the claims and equivalents thereof.

Claims

1. An application of a low surface energy corrosion-resistant polyurethane self-lubricating material, characterized in that, Low surface energy corrosion-resistant polyurethane self-lubricating material and alkali-reduced lignin modified with titanate coupling agent are mechanically stirred to obtain a mixed solution. The mixed solution is sprayed onto the surface of the substrate and cured at high temperature to obtain a low surface energy corrosion-resistant polymer lubricating coating. The alkali-reduced lignin modified with titanate coupling agent accounts for 1~10 wt% of the mass of the mixed solution.

2. The application of the low surface energy corrosion-resistant polyurethane self-lubricating material as described in claim 1, characterized in that, The low surface energy corrosion-resistant polyurethane self-lubricating material is applied to the surface of a substrate and cured to obtain a low surface energy corrosion-resistant polymer lubricating coating. The specific method includes: fully mixing the low surface energy corrosion-resistant polyurethane self-lubricating material and solid filler in mechanical stirring to obtain a mixed solution, spraying the mixed solution onto the surface of the treated substrate, and curing at high temperature to obtain a low surface energy corrosion-resistant polymer lubricating coating. The titanate coupling agent-modified alkali-reduced lignin is replaced by one or a combination of organosilicon microspheres, carbon black, alkali-reduced lignin, and colloidal silica. The spraying pressure is 0.2~0.6MPa, the distance between the spray gun nozzle and the substrate surface is 20~40cm, and the spraying is repeated 6~8 times; the high-temperature curing temperature is 75~85℃, and the curing time is 6~18h; the thickness of the low surface energy corrosion-resistant polymer lubricating coating is 5~50 micrometers.

3. The application of the low surface energy corrosion-resistant polyurethane self-lubricating material as described in claim 1, characterized in that, The preparation method of the titanate coupling agent modified alkali-reduced lignin includes: S1. Disperse the alkali-degraded lignin in N,N-dimethylformamide to obtain a suspension; heat the suspension to 80~90℃, add isopropyltris(dioctylphosphoyloxy)titanate, react under nitrogen atmosphere for 4~8h, and cool to room temperature to obtain the reaction solution; S2, the reaction solution is transferred to a high-pressure reactor, stearic acid is added, and the reaction is carried out at 120~150℃ for 8~12h. After cooling to room temperature, the precipitate is vacuum dried at 60~80℃ to constant weight to obtain alkali-reduced lignin modified with titanate coupling agent.

4. The application of the low surface energy corrosion-resistant polyurethane self-lubricating material as described in claim 3, characterized in that, In S1, the ratio of dealkalized lignin to N,N-dimethylformamide is 1~10g:100~150mL; the mass of isopropyltris(dioctylphosphoyloxy)titanate is 1%~10% of the mass of the dealkalized lignin. In S2, the amount of stearic acid used is 1% to 5% of the dealkalized lignin quality.

5. A method for preparing a low surface energy corrosion-resistant polyurethane self-lubricating material, wherein the low surface energy corrosion-resistant polyurethane self-lubricating material is the low surface energy corrosion-resistant polyurethane self-lubricating material used in any one of claims 1-4, characterized in that, Includes the following steps: Step 1: Mix polyether polyol, single-terminated dihydroxy polydimethylsiloxane and diisocyanate and add catalyst, and react under nitrogen atmosphere; Step 2: Add the crosslinking agent dissolved in an organic solvent to the reaction system and heat the reaction; add the chain extender and heat the reaction. Step 3: Cool the system and add the chain extender again. Heat the system to react completely with the remaining NCO groups. Turn off the heating and cool to room temperature. Add triethylamine to neutralize the carboxyl groups. Step 4: Add deionized water and stir vigorously to emulsify completely, obtaining a white polymer; mix the white polymer and the post-crosslinking agent thoroughly with mechanical stirring to obtain a low surface energy corrosion-resistant polyurethane self-lubricating material.

6. The method for preparing the low surface energy corrosion-resistant polyurethane self-lubricating material as described in claim 5, characterized in that, In step one, the polyether polyol is selected from one or more of polytetrahydrofuran, polyethylene glycol, and polypropylene glycol; the amount of the polyether polyol is 60-70 wt% of the total mass of the polyether polyol, single-terminated dihydroxy polydimethylsiloxane and diisocyanate.

7. The preparation method of the low surface energy corrosion-resistant polyurethane self-lubricating material as described in claim 5, characterized in that, In step one, the molecular weight of the single-ended dihydroxy polydimethylsiloxane is 4000-5000; the amount of the single-ended dihydroxy polydimethylsiloxane is 0-10 wt% of the total mass of the polyether polyol, the single-ended dihydroxy polydimethylsiloxane and the diisocyanate.

8. The method for preparing the low surface energy corrosion-resistant polyurethane self-lubricating material as described in claim 5, characterized in that, In step one, the diisocyanate is selected from one or more of the following: isophorone diisocyanate, terephthalic diisocyanate, toluene 2,6 diisocyanate, hexamethylene diisocyanate, etc.; the amount of the diisocyanate is 20-30 wt% of the total mass of polyether polyol, single-terminated dihydroxy polydimethylsiloxane and diisocyanate.

9. The preparation method of the low surface energy corrosion-resistant polyurethane self-lubricating material as described in claim 5, characterized in that, In step one, the catalyst includes one or more of dibutyltin dilaurate, zinc isooctanoate, or bismuth isooctanoate, and the mass of the catalyst is 1% to 5% of the mass of the polyether polyol, mono-terminated dihydroxy polydimethylsiloxane, and diisocyanate. In step two, the organic solvent is one or a combination of several of N,N-dimethylformamide, ethanol, xylene, petroleum ether, ethyl acetate, butyl acetate, and N-methylpyrrolidone. The crosslinking agent is selected from one or a combination of several of the following: trimethylolpropane, dicumyl peroxide, formaldehyde, and sulfur; the amount of the crosslinking agent is 1% to 5% of the mass of the polyether polyol, single-terminated dihydroxy polydimethylsiloxane, and diisocyanate. In steps two and three, the chain extender is selected from one or a combination of several of the following: 2,2-dimethylolpropionic acid, 1,4-butanediol, ethylene glycol, neopentyl glycol, and propylene glycol. In step two, the chain extender is used at a rate of 1% to 5% of the mass of the polyether polyol, the mono-terminated dihydroxy polydimethylsiloxane, and the diisocyanate. In step three, the amount of chain extender used is 1% to 5% of the mass of polyether polyol, single-terminated dihydroxy polydimethylsiloxane, and diisocyanate.

10. The method for preparing the low surface energy corrosion-resistant polyurethane self-lubricating material as described in claim 5, characterized in that, In step four, the post-crosslinking agent includes one or a combination of several of the following: aziridine, polycarbodiimide, and hexamethylene diisocyanate isocyanurate trimer; the amount of the post-crosslinking agent is 0.1% to 5% of the mass of the polyether polyol, mono-terminated dihydroxy polydimethylsiloxane, and diisocyanate. The amount of deionized water used is 2 to 3 times the mass of polyether polyol, single-terminated dihydroxy polydimethylsiloxane and diisocyanate, resulting in a solid content of 25% to 33%.

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