Waterborne polyurethane formula and production process thereof

Abstract

The invention relates to the technical field of application of waterborne polyurethane to production of condoms, and discloses a waterborne polyurethane formula and a production process thereof, and the waterborne polyurethane formula comprises the following raw materials: PTMG 1000, DMPA, BDO, zinc isoocatanoate, IPDI, acetone, triethylamine, a 20% ethylenediamine aqueous solution, deionized water, and a nano-silica modifier. The raw materials comprise, by weight, 17.22% of PTMG 1000, 0.65% of DMPA, 0.18% of BDO, 0.00344% of zinc isoocatanoate, 7.47% of IPDI, 12.05% of acetone, 0.49% of triethylamine, 2.02% of a 20% ethylenediamine aqueous solution, 59.91% of deionized water, and a nano-silica modifier accounting for 0.5%-1.5% of the total weight of the raw materials. The water resistance of the waterborne polyurethane is good, and the water absorption rate is reduced along with the increase of the dosage of the nano silicon dioxide modifier. In the use process of the condom, when the condom is in contact with liquid such as body fluid, the problems of material softening, strength reduction and the like caused by water absorption can be effectively prevented, the integrity and functionality of the condom are maintained, and the contraception and protection effects are not affected.

Description

Technical Field

[0001] The invention relates to the technical field of waterborne polyurethane production applied in the condom industry, in particular to a waterborne polyurethane formula and a production process thereof. Background Art

[0002] Waterborne polyurethane is a polyurethane system with water as the dispersion medium. Due to its environmental protection and good film-forming properties, it can form a uniform, continuous and elastic film during the condom production process. This film gives the condom excellent strength and flexibility, making it difficult to break during use, effectively improving the reliability of contraception and prevention of sexually transmitted diseases.

[0003] Compared with traditional natural rubber condoms, condoms made of water-based polyurethane have excellent tensile properties and can withstand greater deformation without breaking, providing safer protection for users.

[0004] In the prior art, there are many studies and patents on waterborne polyurethane. After searching, a patent with patent application number CN202010585065.2 discloses a high-solid content waterborne polyurethane and its preparation method, the main components of which include 40-60 parts of isocyanates, 60-80 parts of polyols, 0.2-0.5 parts of catalysts, 3-10 parts of alcohol chain extenders, 5-8 parts of amine chain extenders, 5-10 parts of hydrophilic chain extenders, 1-10 parts of small molecule chain extenders, 1-3 parts of end-capping agents, 3-5 parts of salt-forming agents, 30-50 parts of solvents, and 100-200 parts of emulsifiers.

[0005] It can be seen from the specific process recorded that it has the following shortcomings: First, in terms of raw material processing, polyols, alcohol chain extenders, etc. are only simply vacuum dried at 100-120°C for 2-3 hours, lacking in-depth control over the purity and fineness of the raw materials.

[0006] Although the comparative documents emphasize high solid content, weather resistance, and acid and alkali resistance, they do not fully consider product stability. The use of additives such as antioxidants and light stabilizers is not mentioned. During long-term storage and use, performance may deteriorate due to oxidation, light, and other factors. During the reaction process, the reaction is carried out only by controlling the temperature and time. Without advanced technical means such as microwave assisted heating, ultrasonic treatment, and microchannel reactors, it is difficult to achieve precise control and optimization of the reaction process. Based on this, the present invention optimizes and improves the problems existing in the prior art, and hereby proposes a waterborne polyurethane formula and a production process thereof. Summary of the invention

[0007] The present invention solves one of the above technical problems, and the technical scheme adopted is: a water-based polyurethane formula, comprising the following raw materials: PTMG1000 (polytetramethylene glycol, molecular weight 1000), DMPA (dimethylol propionic acid), BDO (1,4-butanediol), zinc isooctanoate, IPDI (isophorone diisocyanate), acetone (urethane grade), triethylamine, 20% ethylenediamine aqueous solution, deionized water, and also comprising a nano-silica modifier; in terms of weight percentage of each raw material, PTMG1000 accounts for 17.22%, DMPA accounts for 0.65%, BDO accounts for 0.18%, zinc isooctanoate accounts for 0.00344%, IPDI accounts for 7.47%, acetone accounts for 12.05%, triethylamine accounts for 0.49%, 20% ethylenediamine aqueous solution accounts for 2.02%, deionized water accounts for 59.91%, and the nano-silica modifier accounts for 0.5%-1.5% of the total raw material weight.

[0008] In any of the above schemes, preferably, the particle size of the nano-silica modifier is 5-20 nanometers, and its surface is treated with a silane coupling agent, and the amount of the silane coupling agent is 1%-3% of the weight of the nano-silica modifier.

[0009] In any of the above schemes, it is preferred that an antioxidant 1010 is also included, and the antioxidant 1010 accounts for 0.1%-0.3% of the total raw material weight.

[0010] In any of the above schemes, it is preferred that the light stabilizer UV-531 is also included, and the light stabilizer UV-531 accounts for 0.05%-0.2% of the total raw material weight.

[0011] In any of the above schemes, preferably, the BDO is subjected to a molecular sieve dehydration treatment before being added to the reaction system to make its water content less than 0.01%.

[0012] In any of the above schemes, preferably, the DMPA is purified by recrystallization before use, the recrystallization solvent is anhydrous ethanol, and the number of recrystallizations is 2-3 times.

[0013] The present invention also provides a production process of a waterborne polyurethane formulation, comprising the following steps: S1: Raw material pretreatment steps: The nano-silicon dioxide modifier is placed in a high-speed disperser and dispersed at a speed of 3000-5000 rpm for 20-30 minutes, and a silane coupling agent is added at 1%-3% of the weight of the nano-silicon dioxide modifier for surface treatment; Dehydration of BDO using molecular sieves until its water content is less than 0.01%; If the formula contains DMPA, it is purified by recrystallization with anhydrous ethanol 2-3 times. During recrystallization, DMPA is heated and dissolved in anhydrous ethanol at a temperature of 60-70°C, then slowly cooled to 0-5°C, and the crystallization time is 4-6 hours. After filtering, it is dried in a vacuum drying oven at 40-50°C for 4-6 hours; If the formula contains antioxidant 1010 and light stabilizer UV-531, weigh them accurately and set aside; S2: Prepolymer preparation steps: In a three-necked round-bottom flask equipped with a mechanical stirrer, a reflux condenser, and a thermocouple, 100 g of PTMG1000 and 3.8 g of DMPA were added, and dehydrated at 100 °C and -0.1 MPa vacuum for 2 h; The temperature was lowered to 80°C, 1.04 g of dehydrated BDO was added, and dehydration was continued for 30 min under a vacuum of -0.1 MPa; The vacuum was released, nitrogen was filled for protection, and 43.41 g IPDI, 0.02 g zinc isooctanoate and pretreated nano-silica modifier were added; The temperature was raised to 90°C, microwave-assisted heating was used, the microwave power was 300-500W, the reaction system was ultrasonically treated for 5min every 30min during the reaction, the ultrasonic power was 100-200W, the reaction was carried out for 2-2.5h, and then the NCO content in the reaction system was titrated by toluene-di-n-butylamine method; S3: Additive addition step: If the formula contains antioxidant 1010 and light stabilizer UV-531, after the prepolymer reaction is completed and the NCO content reaches the standard, the reaction temperature is lowered to 60°C, antioxidant 1010 and light stabilizer UV-531 are added, and stirred at a stirring speed of 200-300 rpm for 20-30 minutes to fully disperse them; S4: neutralization and emulsification step; Among them, the neutralization and emulsification steps are specifically as follows: When the NCO content in the system reaches 3.17%, cool the PU prepolymer to 50°C, add 70g of acetone, and dissolve it at a stirring speed of 150-200rpm for 15-30min; Add 2.87 g of triethylamine, use a pH meter to monitor the pH value of the system in real time, neutralize for 30 minutes, and control the pH value between 7.5-8.5; Turn on high-speed stirring (300-500 rpm) and ultrasonic-assisted dispersion device (ultrasonic power is 100-200 W), add 348 g of deionized water, and continue stirring and dispersing for 30 minutes; A peristaltic pump was used to slowly drop 11.75 g of a 20% ethylenediamine aqueous solution at a rate of 0.5-1 mL / min. After the addition was complete, the chain was extended for 30 min. An online viscosity monitoring system was used to monitor the viscosity of the system in real time. When the viscosity of the system reached 200-300 mPas, the rate of addition of triethylamine and deionized water was adjusted. S5: Post-processing steps: The obtained emulsion was subjected to reduced pressure distillation at 30°C and -0.09MPa using a thin film evaporator to remove acetone from the emulsion, with the scraper speed of the thin film evaporator being 100-200rpm; The emulsion after deacetone removal is subjected to ultrafiltration purification, and the molecular weight cut-off of the ultrafiltration membrane is 5000-10000Da; Add 0.05%-0.1% of the weight of the emulsion to the refined emulsion (such as isothiazolinone fungicide), stir evenly, and place at room temperature for 2-4 hours; The sterilized aqueous polyurethane emulsion is aged in a sealed container at 25-30° C. for 2-3 days.

[0014] In any of the above schemes, it is preferred that in the prepolymer preparation step, a microchannel reactor is used for the reaction, and PTMG1000, DMPA, BDO, IPDI, zinc isooctanoate and nano-silica modifier are respectively injected into the microchannel reactor at precise flow rates through metering pumps, the inner diameter of the microchannel is 0.5-2 mm, and the reaction residence time is 1-2 h. By accurately controlling the flow rate and reaction residence time, the uniformity of the reaction and the consistency of the product are improved.

[0015] In any of the above schemes, it is preferred that after the neutralization and emulsification step, a high-pressure homogenization step is added, and the neutralized and emulsified emulsion is treated by a high-pressure homogenizer, the homogenization pressure is 50-100 MPa, and the homogenization times are 2-3 times. The high-pressure homogenization further reduces the particle size of the emulsion particles and improves the stability and dispersibility of the emulsion.

[0016] In any of the above schemes, it is preferred that after the ultrafiltration refining in the post-treatment step, an ion exchange step is added, and the ultrafiltered emulsion is passed through an ion exchange resin column to remove residual metal ions and impurity ions in the emulsion, and the ion exchange resin is a combination of a strongly acidic cation exchange resin and a strongly basic anion exchange resin, so as to further improve the purity and stability of the product.

[0017] In any of the above schemes, it is preferred that in the raw material pretreatment step, the nano-silica modifier is subjected to plasma surface treatment, the nano-silica modifier is placed in a plasma treatment device, a mixed gas of argon and oxygen (the volume ratio of argon and oxygen is 3:1) is introduced, the plasma treatment power is 100-200W, and the treatment time is 5-10min, so as to enhance the compatibility and bonding force between the nano-silica modifier and other raw materials.

[0018] In any of the above schemes, it is preferred that in the additive adding step, supercritical carbon dioxide is used to assist in adding antioxidant 1010 and light stabilizer UV-531, and the reaction system is placed in a supercritical carbon dioxide environment with a pressure of 8-12 MPa and a temperature of 35-45°C, so that the antioxidant 1010 and light stabilizer UV-531 are more evenly dispersed in the prepolymer under the action of supercritical carbon dioxide, thereby improving the dispersion effect and action efficiency of the additives.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. By adding nano-silica modifiers and optimizing the production process, condoms made of water-based polyurethane have excellent tensile strength and elongation at break. In actual use, they can withstand large external forces without breaking, effectively reducing the risk of condoms breaking during use, greatly improving the reliability of contraception and prevention of sexually transmitted diseases, and providing safer protection for users.

[0020] 2. The product has moderate Shore A hardness and soft texture. This soft feature can significantly reduce the user's foreign body sensation when using the condom, improve the comfort during use, and thus increase the user's acceptance and willingness to use, and enhance the overall user experience.

[0021] 3. As the amount of nano-silica modifier increases, the initial thermal decomposition temperature of the product increases and the thermal stability is enhanced. This feature enables the condom to better maintain its own performance stability when facing different environmental temperature changes during storage and use, effectively extending the shelf life of the product and ensuring that the quality of the condom is reliable and the performance is consistent within the shelf life.

[0022] 4. The water-based polyurethane has good water resistance, and the water absorption rate decreases with the increase of the amount of nano-silica modifier. During the use of condoms, when they come into contact with body fluids and other liquids, they can effectively prevent the softening of the material and the decrease in strength caused by water absorption, maintain the integrity and functionality of the condoms, and ensure that the contraceptive and protective effects are not affected.

[0023] 5. The raw materials are strictly pre-treated in the production process to remove impurities and moisture, reduce substances that may cause allergies and other adverse reactions, and ensure the health and safety of users. At the same time, environmentally friendly raw materials are used in the production process, and organic solvents are removed in the post-processing, which meets environmental protection requirements. While meeting the functional requirements, it reduces pollution to the environment and embodies the concept of sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or components are generally identified by similar reference numerals. In the drawings, the elements or components are not necessarily drawn according to the actual scale.

[0025] Figure 1 This is the process flow of the present invention. DETAILED DESCRIPTION

[0026] The following is a detailed description of the embodiments of the technical solution of the present invention in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present invention. Figure 1 as shown in .

[0027] Example 1: Raw material preparation: Prepare PTMG1000 (17.22%), DMPA (0.65%), BDO (0.18%), zinc isooctanoate (0.00344%), IPDI (7.47%), acetone (12.05%), triethylamine (0.49%), 20% ethylenediamine aqueous solution (2.02%), deionized water (59.91%), and nano-silica modifier (accounting for 0.5% of the total raw material weight) by weight. The particle size of the nano-silica modifier is 5-20 nanometers, and the surface is treated with a silane coupling agent (the amount is 1% of the weight of the nano-silica modifier). BDO is dehydrated with molecular sieves to a water content of less than 0.01%, and DMPA is recrystallized twice with anhydrous ethanol, the heating dissolution temperature is 60°C, the cooling crystallization temperature is 0°C, the crystallization time is 4h, and after filtering, it is dried in a vacuum drying oven at 40°C for 4h.

[0028] It should be noted that: accurate weighing of raw materials ensures the accuracy of the formula; dehydration of BDO and recrystallization and purification of DMPA can remove impurities and moisture, avoid affecting the reaction and improve product quality; surface treatment of nano-silica modifier can enhance its compatibility with other raw materials.

[0029] Preparation of prepolymer: 100g PTMG1000 and 3.8g DMPA were added to a three-necked round-bottom flask equipped with a mechanical stirrer, a reflux condenser, and a thermocouple, and dehydrated for 2h at 100℃ and -0.1MPa vacuum. Cool down to 80℃, add 1.04g dehydrated BDO, and continue dehydrating for 30min at -0.1MPa vacuum. Remove the vacuum, fill with nitrogen protection, add 43.41g IPDI, 0.02g zinc isooctanoate and pretreated nano-silica modifier. Heat to 90℃, microwave-assisted heating (microwave power 300W), ultrasonic treatment for 5min every 30min (ultrasonic power 100W), react for 2h, and titrate the NCO content in the reaction system by toluene-di-n-butylamine method.

[0030] It should be noted that: vacuum dehydration is used in the early stage to remove moisture from the raw materials to prevent moisture from reacting with isocyanate to produce by-products; nitrogen protection is used to prevent the raw materials from being oxidized; microwave and ultrasound-assisted heating can accelerate the reaction rate, make the reaction more complete, and improve production efficiency. The reaction progress can be monitored by titrating the NCO content.

[0031] Additive addition: No step of adding antioxidant 1010 and light stabilizer UV-531.

[0032] Neutralization and emulsification: When the NCO content of the system reaches 3.17%, cool the PU prepolymer to 50°C, add 70g acetone, and dissolve it at a stirring speed of 150rpm for 20min. Add 2.87g triethylamine, monitor the pH value with a pH meter, neutralize for 30min, and control the pH value between 7.5-8.5. Turn on high-speed stirring (300rpm) and ultrasonic-assisted dispersion device (ultrasonic power 100W), add 348g deionized water, and stir and disperse for 30min. Use a peristaltic pump to slowly add 11.75g ​​20% ​​ethylenediamine aqueous solution at a dropping speed of 0.5mL / min. After the addition is completed, extend the chain for 30min, and use an online viscosity monitoring system to monitor the system viscosity in real time. When the system viscosity reaches 200-300mPas, adjust the addition rate of triethylamine and deionized water.

[0033] It should be noted that: acetone dissolves the prepolymer to make it more evenly dispersed; triethylamine neutralizes the carboxyl group on DMPA to give the polyurethane hydrophilicity; high-speed stirring and ultrasound-assisted dispersion can make the system more evenly emulsified; ethylenediamine aqueous solution chain extension increases the molecular chain length, improves the polymer molecular weight and performance; monitors the viscosity and adjusts the additive speed to ensure stable product quality.

[0034] Post-treatment: Remove acetone from the emulsion by vacuum distillation with a thin film evaporator at 30°C and -0.09MPa, with a scraper speed of 100rpm. The emulsion after deacetone removal is refined by ultrafiltration, and the molecular weight cutoff of the ultrafiltration membrane is 5000Da. Add 0.05% of the weight of the emulsion to the refined emulsion. Stir evenly and place at room temperature for 2 hours. The sterilized aqueous polyurethane emulsion is aged in a sealed container at 25°C for 2 days.

[0035] It should be noted that: removing acetone by reduced pressure distillation can prevent its residue from affecting product performance; ultrafiltration refining removes large molecular impurities and unreacted small molecular substances to improve product purity; adding bactericides prevents the growth of microorganisms and extends the shelf life of the product; aging makes the emulsion performance more stable and improves product consistency.

[0036] Example 2: Raw material preparation: The raw material composition is the same as that of Example 1, the nano-silica modifier accounts for 1% of the total raw material weight, and the amount of silane coupling agent is 2% of the weight of the nano-silica modifier. BDO is dehydrated to a water content of less than 0.01%, DMPA is recrystallized 3 times with anhydrous ethanol, the heating dissolution temperature is 65°C, the cooling crystallization temperature is 3°C, the crystallization time is 5h, and after filtering, it is dried in a vacuum drying oven at 45°C for 5h.

[0037] It should be noted that: similar to Example 1, the amount of nano-silica modifier and silane coupling agent, the number and conditions of DMPA recrystallization are adjusted to explore their effects on product performance and provide data support for process optimization; BDO ​​dehydration ensures smooth reaction and avoids water interference.

[0038] Preparation of prepolymer: The operation was the same as in Example 1, except that the microwave power was 400 W, the ultrasonic power was 150 W, and the reaction time was 2.2 h.

[0039] It should be noted that: by changing the microwave and ultrasonic power and reaction time, studying their effects on reaction rate, product structure and performance, finding the optimal reaction conditions, and improving product quality and production efficiency.

[0040] Addition of additives: After the prepolymer reaction is completed and the NCO content reaches the standard, the reaction temperature is lowered to 60°C, 0.1% of the total raw material weight of antioxidant 1010 and 0.05% of the light stabilizer UV-531 are added, and stirring is carried out at a stirring speed of 250 rpm for 25 minutes.

[0041] It should be noted that adding antioxidants and light stabilizers can improve the product's antioxidant and anti-light aging properties and extend the product's service life; controlling the stirring speed and time can ensure that the additives are evenly dispersed in the prepolymer to give full play to their role.

[0042] Neutralization and emulsification: The operation is the same as in Example 1, but the stirring speed and ultrasonic power are both taken at intermediate values, that is, the stirring speed is 175 rpm when dissolving the prepolymer, and the stirring speed is 400 rpm and the ultrasonic power is 150 W during high-speed stirring and ultrasonic-assisted dispersion.

[0043] It should be noted that the stirring and ultrasonic parameters were adjusted to study their effects on the emulsification effect and emulsion stability, optimize the process conditions, ensure uniform dispersion of emulsion particles, and improve product quality.

[0044] Post-treatment: The operation is the same as in Example 1, but the ultrafiltration membrane has a molecular weight cut-off of 8000 Da, the amount of bactericide is 0.08% of the weight of the emulsion, the aging temperature is 28° C., and the aging time is 2.5 days.

[0045] It should be noted that changing the ultrafiltration membrane cutoff molecular weight can control the range of impurity removal and further optimize product purity; adjusting the dosage of fungicide and aging conditions to explore its impact on the product's anti-corrosion performance and stability can ensure stable and reliable product quality.

[0046] Example 3: Raw material preparation: The raw material composition is the same as in Example 1, the nano-silica modifier accounts for 1.5% of the total raw material weight, and the silane coupling agent is used in an amount of 3% of the weight of the nano-silica modifier. BDO is dehydrated to a water content of less than 0.01%, DMPA is recrystallized 3 times with anhydrous ethanol, the heating dissolution temperature is 70°C, the cooling crystallization temperature is 5°C, the crystallization time is 6h, and after filtering, it is dried in a vacuum drying oven at 50°C for 6h.

[0047] It should be noted that: further increasing the dosage of nano-silica modifier and silane coupling agent, changing the DMPA recrystallization conditions, studying their effects on product performance, and providing a reference for the development of high-performance waterborne polyurethane; ensuring the processing quality of BDO and DMPA to avoid impurities and moisture affecting the reaction.

[0048] Prepolymer preparation: The reaction was carried out in a microchannel reactor. PTMG1000, DMPA, BDO, IPDI, zinc isooctanoate and nano-silica modifier were injected at precise flow rates through metering pumps. The inner diameter of the microchannel was 1 mm and the reaction residence time was 1.5 h.

[0049] It should be noted that the use of microchannel reactors can accurately control reaction conditions, improve reaction uniformity and product consistency, reduce the occurrence of side reactions, improve product quality and production efficiency, and achieve continuous production.

[0050] Additive addition: same as Example 2.

[0051] Neutralization and emulsification: Same as Example 2, but a high-pressure homogenization step is added after neutralization and emulsification. The emulsion is processed by a high-pressure homogenizer with a homogenization pressure of 75 MPa and two homogenization times.

[0052] It should be noted that high-pressure homogenization can further reduce the particle size of emulsion particles, improve the stability and dispersibility of the emulsion, make the product more uniform during the application process, and improve product performance and use effect.

[0053] Post-treatment: Same as Example 2, but an ion exchange step is added after ultrafiltration refining, and the emulsion is passed through an ion exchange resin column composed of a strong acid cation exchange resin and a strong basic anion exchange resin to remove residual metal ions and impurity ions.

[0054] It should be noted that ion exchange can effectively remove impurity ions in the emulsion, improve product purity and stability, and meet the strict requirements of high-end application fields for product quality.

[0055] Example 4: Raw material preparation: Same as Example 3, and in the raw material pretreatment step, the nano-silica modifier is subjected to plasma surface treatment, placed in a plasma treatment device, and introduced with a mixed gas of argon and oxygen (volume ratio 3:1), the plasma treatment power is 150 W, and the treatment time is 8 min.

[0056] It should be noted that plasma surface treatment can enhance the compatibility and bonding force between the nano-silica modifier and other raw materials, improve the dispersibility of nano-silica in the polyurethane system, and thus improve product performance.

[0057] Preparation of prepolymer: same as Example 3.

[0058] Additive addition: Antioxidant 1010 and light stabilizer UV-531 were added with the aid of supercritical carbon dioxide, and the reaction system was placed in a supercritical carbon dioxide environment with a pressure of 10 MPa and a temperature of 40°C.

[0059] It should be noted that the auxiliary addition of supercritical carbon dioxide can make the antioxidants and light stabilizers more evenly dispersed in the prepolymer, improve the dispersion effect and efficiency of the additives, and give full play to their antioxidant and anti-light aging properties.

[0060] Neutralization and emulsification: Same as Example 3.

[0061] Post-treatment: Same as Example 3.

[0062] Example 5: Raw material preparation: same as Example 4.

[0063] Preparation of prepolymer: Same as Example 3, but adjusting the flow rate of each raw material in the microchannel reactor so that the reaction residence time is 2 h.

[0064] It should be noted that by changing the reaction residence time, studying its effect on the reaction process and product performance, the reaction conditions of the microchannel reactor are further optimized to improve product quality and production efficiency.

[0065] Additive addition: same as Example 4.

[0066] Neutralization and emulsification: Same as in Example 3, but the high-pressure homogenization pressure is 100 MPa and the homogenization times are 3 times.

[0067] It should be noted that higher homogenization pressure and more homogenization times can more effectively reduce the particle size of emulsion particles, significantly improve the stability and dispersibility of the emulsion, and enhance product performance.

[0068] Post-treatment: Same as Example 3, except that the amount of bactericide used was 0.1% of the weight of the emulsion, the aging temperature was 30° C., and the aging time was 3 days.

[0069] It should be noted that the dosage of fungicide and aging conditions should be adjusted to further optimize the product's antiseptic properties and stability and ensure the quality reliability of the product during storage and use.

[0070] The products of this waterborne polyurethane formula production process are applied to condoms, which can bring many beneficial effects in terms of material performance, safety, production and environmental protection, as follows: 1. The addition of nano-silica modifier in the formula and the reasonable preparation process make the product have good tensile strength and elongation at break. In condom applications, it can fit the human body closely, withstand large stretching without breaking during use, and adapt to different shapes and movements, providing a more comfortable and fitting experience.

[0071] For example, experimental data show that as the amount of nano-silica modifier increases, the tensile strength of the product improves, which can better meet the tensile requirements of condoms in actual use and ensure their integrity and safety.

[0072] 2. The hardness of the product is moderate, and the Shore A hardness is within the appropriate range, making the condom soft. This helps to improve the user's comfort, reduce the foreign body sensation, and increase the willingness and satisfaction of use. For example, the precise proportioning and processing of each raw material in the production process ensures that the product can achieve the appropriate hardness and provide users with a soft and comfortable touch.

[0073] 3. The product has high thermal stability, and the initial thermal decomposition temperature increases with the increase in the amount of nano-silica modifier. During the storage and use of condoms, it can better resist certain temperature changes, ensure the stability of its performance, and extend the shelf life and use effect of the product. For example, in some high-temperature environments, condoms with good thermal stability can maintain their original performance and will not have quality problems due to temperature influences.

[0074] 4. The water resistance of the product is enhanced, and the water absorption rate decreases with the increase of the amount of nano-silica modifier. This is very important for condoms that come into contact with body fluids and other liquids during use. It can prevent the performance from being degraded due to water absorption and maintain its integrity and functionality. For example, in actual use, it can better resist the erosion of body fluids and ensure the effect of contraception and protection.

[0075] 5. Strict pretreatment of raw materials in the production process, such as BDO dehydration, DMPA recrystallization purification, etc., to remove impurities and moisture, avoid affecting the reaction, and improve product quality. In condom applications, it can reduce safety hazards such as allergies caused by impurities or impure substances, and ensure the safety and reliability of the product. For example, strict processing of raw materials can make the product meet relevant safety standards and reduce the health risks of users.

[0076] 6. Reasonable addition of antioxidants and light stabilizers and other additives can improve the product's anti-oxidation and anti-light aging properties, extend the product's service life, and also ensure safety during use. For example, antioxidants can prevent the product from oxidizing and deteriorating during storage and use, reduce the generation of harmful substances, and protect the health of users.

[0077] 7. The use of advanced production processes such as microchannel reactors can accurately control reaction conditions, improve reaction uniformity and product consistency, reduce side reactions, and improve product quality and production efficiency. This helps to ensure large-scale and stable production of condoms to meet market demand. For example, microchannel reactors can achieve continuous production, improve production speed and product quality stability.

[0078] 8. Environmentally friendly raw materials such as deionized water are used in the production process, and harmful substances such as organic solvents (such as acetone) can be effectively removed in the post-treatment process, which meets environmental protection requirements. After the condom is used, the pollution to the environment is small, which reflects the concept of environmental protection. Removing acetone by vacuum distillation can prevent its residue from affecting product performance and the environment, and ultrafiltration refining and other processes can also help reduce pollution to the environment.

[0079] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention. For those skilled in the art, any replacement improvements or changes made to the implementation methods of the present invention fall within the protection scope of the present invention.

[0080] The matters not described in detail in the present invention are all known technologies to those skilled in the art.

Claims

1. A waterborne polyurethane formulation, characterized in that: The invention comprises the following raw materials: PTMG1000, DMPA, BDO, zinc isooctanoate, IPDI, acetone, triethylamine, 20% aqueous solution of ethylenediamine, deionized water, and nano-silica modifier; in terms of weight percentage, PTMG1000 accounts for 17.22%, DMPA accounts for 0.65%, BDO accounts for 0.18%, zinc isooctanoate accounts for 0.00344%, IPDI accounts for 7.47%, acetone accounts for 12.05%, triethylamine accounts for 0.49%, 20% aqueous solution of ethylenediamine accounts for 2.02%, deionized water accounts for 59.91%, and the nano-silica modifier accounts for 0.5%-1.5% of the total raw material weight.

2. The aqueous polyurethane formulation according to claim 1, characterized in that: The particle size of the nano-silicon dioxide modifier is 5-20 nanometers, and the surface of the nano-silicon dioxide modifier is treated with a silane coupling agent, and the amount of the silane coupling agent is 1%-3% of the weight of the nano-silicon dioxide modifier.

3. The waterborne polyurethane formulation according to claim 1, characterized in that: The invention also comprises an antioxidant 1010, wherein the antioxidant 1010 accounts for 0.1%-0.3% of the total raw material weight.

4. The waterborne polyurethane formulation according to claim 1, characterized in that: The invention also contains light stabilizer UV-531, wherein the light stabilizer UV-531 accounts for 0.05%-0.2% of the total raw material weight.

5. The waterborne polyurethane formulation according to claim 1, characterized in that: Before being added into the reaction system, the BDO is subjected to a molecular sieve dehydration treatment to make its water content less than 0.01%.

6. The waterborne polyurethane formulation according to claim 1, characterized in that: The DMPA is purified by recrystallization before use, the recrystallization solvent is anhydrous ethanol, and the number of recrystallizations is 2-3 times.

7. A production process based on the waterborne polyurethane formulation according to any one of claims 1 to 6, characterized in that: The steps include: S1: Raw material pretreatment steps: The nano-silicon dioxide modifier is placed in a high-speed disperser and dispersed at a speed of 3000-5000 rpm for 20-30 minutes, and a silane coupling agent is added at 1%-3% of the weight of the nano-silicon dioxide modifier for surface treatment; Dehydration of BDO using molecular sieves until its water content is less than 0.01%; If the formula contains DMPA, it is purified by recrystallization with anhydrous ethanol 2-3 times. During recrystallization, DMPA is heated and dissolved in anhydrous ethanol at a temperature of 60-70°C, then slowly cooled to 0-5°C, and the crystallization time is 4-6 hours. After filtering, it is dried in a vacuum drying oven at 40-50°C for 4-6 hours; If the formula contains antioxidant 1010 and light stabilizer UV-531, weigh them accurately and set aside; S2: Prepolymer preparation steps: In a three-necked round-bottom flask equipped with a mechanical stirrer, a reflux condenser, and a thermocouple, 100 g of PTMG1000 and 3.8 g of DMPA were added, and dehydrated at 100 °C and -0.1 MPa vacuum for 2 h; The temperature was lowered to 80°C, 1.04 g of dehydrated BDO was added, and dehydration was continued for 30 min under a vacuum of -0.1 MPa; The vacuum was released, nitrogen was filled for protection, and 43.41 g IPDI, 0.02 g zinc isooctanoate and pretreated nano-silica modifier were added; The temperature was raised to 90°C, microwave-assisted heating was used, the microwave power was 300-500W, the reaction system was ultrasonically treated for 5min every 30min during the reaction, the ultrasonic power was 100-200W, the reaction was carried out for 2-2.5h, and then the NCO content in the reaction system was titrated by toluene-di-n-butylamine method; S3: Additive addition step: If the formula contains antioxidant 1010 and light stabilizer UV-531, after the prepolymer reaction is completed and the NCO content reaches the standard, the reaction temperature is lowered to 60°C, antioxidant 1010 and light stabilizer UV-531 are added, and stirred at a stirring speed of 200-300 rpm for 20-30 minutes to fully disperse them; S4: neutralization and emulsification step; S5: Post-processing steps: The obtained emulsion was subjected to reduced pressure distillation at 30°C and -0.09MPa using a thin film evaporator to remove acetone from the emulsion, with the scraper speed of the thin film evaporator being 100-200rpm; The emulsion after deacetone removal is subjected to ultrafiltration purification, and the molecular weight cut-off of the ultrafiltration membrane is 5000-10000Da; Add 0.05%-0.1% of the weight of the emulsion to the refined emulsion (such as isothiazolinone fungicide), stir evenly, and place at room temperature for 2-4 hours; The sterilized aqueous polyurethane emulsion is aged in a sealed container at 25-30° C. for 2-3 days.

8. The production process of waterborne polyurethane according to claim 7, characterized in that: In the prepolymer preparation step, a microchannel reactor is used for reaction, and PTMG1000, DMPA, BDO, IPDI, zinc isooctanoate and nano-silica modifier are respectively injected into the microchannel reactor at precise flow rates through metering pumps. The inner diameter of the microchannel is 0.5-2 mm, and the reaction residence time is 1-2 hours. By precisely controlling the flow rate and reaction residence time, the uniformity of the reaction and the consistency of the product are improved.

9. The production process of waterborne polyurethane according to claim 8, characterized in that: After the neutralization and emulsification step, a high-pressure homogenization step is added, and the neutralized and emulsified emulsion is processed by a high-pressure homogenizer, the homogenization pressure is 50-100MPa, and the homogenization times are 2-3 times. The high-pressure homogenization further reduces the particle size of the emulsion particles and improves the stability and dispersibility of the emulsion.

10. The production process of waterborne polyurethane according to claim 9, characterized in that: After the ultrafiltration refining in the post-treatment step, an ion exchange step is added to pass the ultrafiltered emulsion through an ion exchange resin column to remove residual metal ions and impurity ions in the emulsion. The ion exchange resin is a combination of a strongly acidic cation exchange resin and a strongly basic anion exchange resin, which further improves the purity and stability of the product.

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