CN117364345A - Hyperbranched TPU nanofiber waterproof and moisture-permeable membrane and preparation and application thereof - Google Patents

Abstract

The invention provides a hyperbranched TPU nanofiber waterproof and moisture-permeable membrane and preparation and application thereof, wherein the preparation raw materials of the hyperbranched TPU nanofiber waterproof and moisture-permeable membrane mainly comprise fluorine-containing hydroxyl aminosilane and diisocyanate, and the fluorine-containing hydroxyl aminosilane is prepared by adding diethanolamine after hydrolytic condensation of halogenated unsaturated silane and perfluoropolyether alcohol. Hyperbranched polyol is prepared by initiating the addition of amino groups in amino alcohol and unsaturated fluorine-containing silane, and the hyperbranched polyol is reacted with diisocyanate to prepare the hyperbranched TPU polymer. The nanofiber membrane prepared by melt spinning of the polymer has a large number of nano microporous structures, and dense connection is formed between holes due to the existence of perfluoropolyether, so that the nanofiber membrane has excellent waterproof moisture permeability and good rebound resilience.

Description

A hyperbranched TPU nanofiber waterproof and moisture-permeable membrane and its preparation and application

Technical field

The invention relates to the technical field of TPU fiber membranes, and in particular to a hyperbranched TPU nanofiber waterproof and moisture-permeable membrane and its preparation and application.

Background technique

Nowadays, air conditioners have entered thousands of households and become a necessity in our lives. However, due to the use of air conditioners, the airtightness of the space has caused "air conditioning disease". Indoor air quality has attracted more and more people's attention. On the other hand, according to survey statistics, industry, construction, and transportation are the three main parts of energy consumption. The energy directly consumed during the construction and use of buildings is close to 1/3 of the total energy consumption in society, and among this energy consumption for heating and air conditioning Accounting for about 65%. In order to solve these problems, more and more people are committed to the innovation of traditional air conditioners: not only ensuring the circulation of indoor and outdoor air, but also reducing energy consumption as much as possible.

Currently, full heat exchangers are the best way to solve the above problems. As an air conditioning auxiliary device, it allows indoor and outdoor air to flow between each other, and exchanges the energy of fresh air and exhaust air through its core component-the total heat exchange membrane. This not only circulates the air, but also reduces the energy consumption of the air conditioner. At present, total heat exchangers have entered the industrial production stage, but many products use paper membranes as total heat exchange membranes. However, with the popularity of total heat exchangers, commonly used heat exchange membrane cores include paper, aluminum foil, polyvinyl alcohol, chitosan, etc. As the use time increases, the shortcomings of these films are gradually exposed. For example, paper films deform, deteriorate, become moldy, and breed bacteria after being used in high-humidity environments. They cannot be cleaned and have a short lifespan; aluminum foil cannot exchange humidity, which reduces The heat exchange efficiency is reduced; the polymer membrane cannot perform humidity exchange, which reduces the heat exchange efficiency. The water vapor transmission rate is low, making it difficult to prepare industrially. In view of this, new total heat exchange membranes have become a hot spot for research. The research mainly focuses on the preparation of various full heat exchange membranes with excellent moisture permeability, high gas barrier properties, non-mold and flame retardant through the compounding of different membrane materials and additives. film, thereby replacing paper film, more effectively reducing air conditioning energy consumption and improving indoor air quality.

Among many polymer material films, TPU film is a high-performance, environmentally friendly film material using TPU polymer as the main raw material. It can be divided into polyester film and polyether film from the chemical composition; from the preparation method, it can be divided into polyester film and polyether film. Divided into melt processing and solution processing. TPU film has excellent properties such as high strength, good toughness, wear resistance, cold resistance, oil resistance, and degradability. It can be used alone or in combination with other materials. In recent years, TPU film products have been widely used in footwear, waterproof and breathable fabrics, high-end handbags and leather goods, inflatable bags and other fields. However, ordinary TPU films still have problems such as poor moisture permeability, poor durability, and low usage rate. Therefore, through It is key to improve the structure of TPU to have more hydrophilic groups, thereby improving the hydrophilic performance of TPU.

Contents of the invention

In order to solve the above-mentioned problems in the prior art, the present invention provides a hyperbranched TPU nanofiber waterproof and breathable membrane and its preparation and application.

A kind of hyperbranched TPU nanofiber waterproof and breathable membrane, which is obtained by polymerizing and spinning diisocyanate and fluorine-containing hydroxylaminosilane under the action of a catalyst, wherein the fluorine-containing hydroxylaminosilane is hydroxyl-terminated perfluoropolyetherol, diethanolamine Prepared with unsaturated halosilane.

In some embodiments of the invention, the diisocyanate is isophorone diisocyanate, dicyclohexylmethane diisocyanate, toluene diisocyanate, 4,4′-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate At least one of isocyanate and hexamethylene diisocyanate.

In some embodiments of the present invention, the preparation method of the fluorine-containing hydroxylaminosilane includes the following steps:

S1: Add unsaturated halogenated silane into the reaction vessel, add hydroxyl-terminated perfluoropolyetherol dropwise while stirring in an oil bath at 50-70°C, add dropwise for 2-3 hours, and raise the temperature of the reaction system to 70-80°C. °C, conduct condensation reflux reaction, the condensation temperature is -10-0 °C, until the system pH is 4.5-6.5, stop heating;

S2: Add diethanolamine and organic solvent 1 to the reaction system obtained in S1 to perform an addition reaction, and then carry out distillation, separation and purification. First, use atmospheric distillation to collect the unreacted hydroxyl-terminated perfluoropolyether alcohol and transition fractions. , and then use vacuum distillation to collect the target product, thereby obtaining the fluorine-containing hydroxylaminosilane.

In some embodiments of the present invention, in the S1, the structure of the unsaturated halogenated silane is R-SiX ₃ , where R ₁ is a C2-5 unsaturated alkenyl group, and X is F, Cl, Br, I .

In some embodiments of the present invention, in the S1, the structure of the hydroxyl-terminated perfluoropolyether alcohol is as shown in Formula I:

;

In formula I, n=4-7, m=6-11; the number average molecular weight of the hydroxyl-terminated perfluoropolyetherol is 1000-1500, and the specific medicine can be purchased from Solvay Company of Italy.

In some embodiments of the present invention, the dosage of the unsaturated halogenated silane and hydroxyl-terminated perfluoropolyether alcohol satisfies the molar ratio of -X:-OH of 1:1-1.5; the unsaturated halogenated The dosage of silane and diethanolamine satisfies the molar ratio of -C=C-:-NH to be 0.8-1:1.

In the present invention, the alcoholysis reaction between unsaturated halosilane and hydroxyl-terminated fluorine-containing polyether alcohol is used to prepare fluorine-containing unsaturated polyether silane. The reaction principle is as shown in Formula II:

;

The secondary amine group in diethanolamine is then used to react with the double bond in the above-mentioned fluorine-containing unsaturated polyether silane to produce hyperbranched diol. During the above reaction process, the inventor found that the molar amount of halogen atoms contained in the unsaturated halosilane in the system should not be too different from the molar amount of hydroxyl groups contained in the hydroxyl-terminated perfluoropolyetherol. If there are too many halogen atoms , will affect the presence of hydroxyl groups in subsequent diethanolamine, thereby affecting the performance of the hyperbranched TPU fiber nanomembrane. After many tests, it was confirmed that the molar ratio of the unsaturated halogenated silane to the hydroxyl-terminated perfluoropolyether alcohol needs to satisfy the molar ratio of -X:-OH to be 1:1-1.5. The reaction between diethanolamine and the unsaturated halogenated silane should try to ensure the complete reaction of the unsaturated halogenated silane to obtain the maximum degree of hyperbranched TPU polymer.

In some embodiments of the present invention, the organic solvent 1 in S2 is at least one of chloroform, dichloromethane, diethyl ether, toluene, methanol, ethanol, and isopropyl alcohol.

In some embodiments of the present invention, the normal pressure distillation in S2 collects the fractions at 75-80°C, and the distillation under reduced pressure collects the fractions at 75-95°C.

A method for preparing the hyperbranched TPU nanofiber waterproof and moisture-permeable membrane, including the following steps: vacuum dehydration of the diisocyanate and fluorine-containing hydroxylaminosilane according to -N=C=O:-OH=2:0.5- Add the molar ratio of 1 into the reactor filled with inert gas, add the organic solvent 2 to dissolve it, add the catalyst accounting for 0.05-0.08wt% of the total reaction system mass, stir the reaction at 40-65°C for 2-3 hours, and then reduce the pressure. The organic solvent 2 is removed by distillation, and electrospinning is used to spin the membrane on the receiving substrate to obtain the hyperbranched TPU nanofiber waterproof and moisture-permeable membrane.

In some embodiments of the present invention, the organic solvent 2 is at least one of alcohol solvents, ether solvents, ketone solvents, tetrahydrofuran (THF), and N,N-dimethylformamide (DMF).

In some embodiments of the present invention, the catalyst is at least one of a tertiary amine catalyst and an organotin catalyst. Specifically, the tertiary amine catalyst can be selected from triethylenediamine, triethylamine, Trimethylbenzylamine, dimethylethanolamine, etc., and the organotin catalyst can be selected from stannous octoate, dibutyltin dilaurate, etc.

In some embodiments of the present invention, the conditions for electrospinning of the hyperbranched TPU polymer are: the receiving substrate is non-woven fabric, glossy paper, aluminum foil, metal mesh, etc., and the perfusion speed is 1-5ml/h, The spinning voltage is 25-50kV, the spinning speed is 50-100r/min, the spinning temperature is 15-30°C, and the relative humidity is 30-90%.

In some embodiments of the present invention, during the preparation process of the hyperbranched TPU polymer, additives that meet the requirements can also be added, such as thermally conductive nanoparticles, bactericides, etc.

The above-mentioned hyperbranched TPU nanofiber waterproof and breathable membrane is used as a total heat exchange membrane in the field of total heat exchangers.

Beneficial effects: Compared with the existing technology, the present invention introduces fluorine-containing unsaturated polyether silane prepared by alcoholysis of perfluoropolyether alcohol and unsaturated halogenated silane into the TPU polymer, forming a hyperbranched structure with the TPU main chain. The large amount of fluorine-containing polyether segments contained in it greatly increases the water resistance of the hyperbranched TPU polymer; during the spinning process, the presence of fluorine and the hyperbranched structure make the final nanofiber membrane possess a large number of nanoscale At the same time, the hydrogen bonds between ether bonds and between ether bonds and amide groups form dense connections between pores, which can not only improve the moisture permeability of the membrane, but also make use of the compatibility of ether bonds with metal materials. properties and increase the thermal conductivity of the film. In addition, the formation of a hyperbranched structure also gives the hyperbranched TPU nanofiber waterproof and moisture-permeable membrane resilience, making it less likely to deform during actual application and increasing its service life.

Detailed ways

The present invention will be described in further detail below with reference to examples. It should be noted that the following examples and comparative examples are examples of the present invention and are only used to illustrate the present invention and are not intended to limit the present invention. Other combinations and various modifications within the concept of the invention can be made without departing from the gist or scope of the invention.

The following is an exemplary description of the preparation process of fluorine-containing hydroxylaminosilane used in the examples:

Fluorinated hydroxylaminosilane-1

S1: Add 3.23g of vinyl trichlorosilane into the reaction vessel, add 30g of hydroxyl-terminated perfluoropolyetherol with a molecular weight of 1000 (customized from Solvay, Italy) dropwise in a 50°C oil bath while stirring. Add for 2 hours, raise the temperature of the reaction system to 70°C for condensation and reflux reaction, the condensation temperature is -10°C, until the pH of the system is 4.5-6.5, stop heating;

S2: Add 1.9g diethanolamine and 50ml chloroform to the reaction system obtained in S1, perform an addition reaction for 5 hours, and then carry out distillation, separation and purification. First, use normal pressure distillation to collect the 75-80°C fraction, and then proceed to 75°C. Collect the target product by rectification under reduced pressure at high temperature to obtain the fluorine-containing hydroxylaminosilane-1.

Fluorinated hydroxyaminosilane-2

S1: Add 5g of propenyl trifluorosilane into the reaction vessel, add 72g of hydroxyl-terminated perfluoropolyether alcohol with a molecular weight of 1000 (customized from Solvay, Italy) while stirring in an oil bath at 60°C, and add dropwise 2h, raise the temperature of the reaction system to 70°C for condensation and reflux reaction, the condensation temperature is -5°C, until the pH of the system is 4.5-6.5, stop heating;

S2: Add 4.75g diethanolamine and 50ml chloroform to the reaction system obtained in S1, perform an addition reaction for 5 hours, and then carry out distillation, separation and purification. First, use normal pressure distillation to collect the 75-80°C fraction, and then proceed to 85°C. The target product is collected by rectification under reduced pressure at high temperature to obtain the fluorine-containing hydroxylaminosilane-2.

Fluorinated hydroxylaminosilane-3

S1: Add 3.34g of pentenyltribromosilane into the reaction vessel, and dropwise add 33.75g of hydroxyl-terminated perfluoropolyetherol with a molecular weight of 1500 in a 70°C oil bath while stirring (customized from Solvay, Italy) , add dropwise for 3 hours, raise the temperature of the reaction system to 80°C for condensation and reflux reaction, the condensation temperature is 0°C, until the system pH is 4.5-6.5, stop heating;

S2: Add 1.17g diethanolamine and 50ml chloroform to the reaction system obtained in S1, perform an addition reaction for 5 hours, and then carry out distillation, separation and purification. First, use normal pressure distillation to collect the 75-80°C fraction, and then collect it at 95°C. The target product is collected by rectification under reduced pressure at high temperature to obtain the fluorine-containing hydroxylaminosilane-3.

Fluorinated hydroxylaminosilane-4

The preparation process is similar to that of fluorinated hydroxylaminosilane-3, except that the mass of the added hydroxyl-terminated perfluoropolyetherol is 25g.

Example 1

A hyperbranched TPU nanofiber waterproof and breathable membrane, the preparation process is as follows: vacuum dehydration of isophorone diisocyanate and fluorine-containing hydroxylaminosilane-1, according to the molar ratio of -N=C=O:-OH=2:0.5 The ratio was added to a reactor filled with nitrogen. After methanol was added to dissolve, dibutyltin dilaurate accounting for 0.05wt% of the total reaction system mass was added. After stirring for 2 hours at 40°C, the methanol was distilled under reduced pressure and electrospinning was used. Spinning on the receiving matrix non-woven fabric to form a film, the spinning conditions are: the perfusion speed is 1ml/h, the spinning voltage is 25kV, the spinning speed is 50r/min, the spinning temperature is 15°C, and the relative humidity is 30% , the hyperbranched TPU nanofiber waterproof and moisture-permeable membrane is obtained.

Example 2

A kind of hyperbranched TPU nanofiber waterproof and breathable membrane. The preparation process is as follows: toluene diisocyanate and fluorine-containing hydroxylaminosilane-2 are vacuum dehydrated, and then filled with water according to the molar ratio of -N=C=O:-OH=2:0.8. In the nitrogen reactor, after adding methanol to dissolve, add 0.06wt% of the total reaction system mass of dibutyltin dilaurate, stir and react at 50°C for 2 hours, then distill the methanol under reduced pressure, and use electrospinning to receive the substrate. Spinning film on aluminum foil, the spinning conditions are: the perfusion speed is 3ml/h, the spinning voltage is 40kV, the spinning speed is 80r/min, the spinning temperature is 20°C, and the relative humidity is 60%, that is, the above Hyperbranched TPU nanofiber waterproof and breathable membrane.

Example 3

A hyperbranched TPU nanofiber waterproof and breathable membrane, the preparation process is as follows: vacuum dehydration of hexamethylene diisocyanate and fluorine-containing hydroxylaminosilane-3, according to the molar ratio of -N=C=O:-OH=2:1 The ratio was added to a reactor filled with nitrogen. After methanol was added to dissolve, 0.08wt% of dibutyltin dilaurate was added, accounting for 0.08wt% of the total reaction system mass. After stirring for 3 hours at 65°C, the methanol was removed by distillation under reduced pressure and electrospinning was used. Spinning the film on the receiving substrate aluminum foil, the spinning conditions are: the perfusion speed is 5ml/h, the spinning voltage is 50kV, the spinning speed is 100r/min, the spinning temperature is 30°C, and the relative humidity is 90%, that is The hyperbranched TPU nanofiber waterproof and breathable membrane is obtained.

Example 4

It is similar to Example 3, except that the raw material is fluorine-containing hydroxylaminosilane-4.

Comparative example 1

Similar to Example 3, except that the fluorine-containing hydroxylaminosilane-3 is replaced by diethanolamine.

Performance Testing

The following performance tests were performed on the hyperbranched TPU nanofiber waterproof and moisture-permeable membrane obtained in the above Examples 1-4 and Comparative 1:

Moisture permeability: Tested in accordance with "GB/T 12704.2-2009 Test Method for Moisture Permeability of Textile Fabrics Part 2: Evaporation Method";

Waterproofness: Tested in accordance with "GB/T 4744-2013 Hydrostatic Pressure Method for Detection and Evaluation of Waterproof Performance of Textiles";

Elastic recovery rate: Tested in accordance with "FZ/T 50007-2012 Spandex Yarn Elasticity Test Method".

The test results are detailed in Table 1:

It can be seen from the data in Table 1 that the hyperbranched TPU nanofiber membrane provided by the present invention has excellent waterproof and moisture permeability. Under the national standard testing conditions, the moisture permeability can reach more than 9000g/(m ² •24h), and the hydrostatic pressure can Reaching more than 50kPa, and has good resilience, the elastic recovery rate can reach more than 85%. In Example 4, due to the change of the raw material ratio for preparing fluorine-containing hydroxylaminosilane, the halogen atoms in the system were not completely hydrolyzed and condensed, which affected the formation of the branched structure of the subsequent TPU polymer, resulting in a lower moisture permeability of the resulting fiber membrane. and water resistance is greatly reduced. In Comparative Example 1, the fluorine-containing hydroxylaminosilane provided by the present invention was not used, and only conventional TPU polymer was used to spin the fiber membrane. The performance of the fiber membrane was not as good as that of the fiber membrane obtained in the embodiment.

In summary, it can be seen that the hyperbranched TPU nanofiber waterproof and moisture-permeable membrane provided by the present invention has excellent waterproof and moisture-permeable properties, good resilience, is not easily deformed during use, and has broad application prospects in the field of total heat exchangers.

Claims (10)

1. The hyperbranched TPU nanofiber waterproof and moisture-permeable membrane is characterized by being prepared by polymerizing diisocyanate and fluorine-containing hydroxyl aminosilane under the action of a catalyst and spinning, wherein the fluorine-containing hydroxyl aminosilane is prepared from hydroxyl-terminated perfluorinated polyether alcohol, diethanolamine and unsaturated halogenated silane.

2. The hyperbranched TPU nanofiber waterproof moisture-permeable film of claim 1, wherein the diisocyanate is at least one of isophorone diisocyanate, dicyclohexylmethane diisocyanate, toluene diisocyanate, 4' -diphenylmethane diisocyanate, 1, 5-naphthalene diisocyanate, and hexamethylene diisocyanate.

3. The hyperbranched TPU nanofiber waterproof and moisture permeable membrane according to claim 1, wherein the preparation method of the fluorine-containing hydroxyl aminosilane comprises the following steps:

s1: adding unsaturated halogenated silane into a reaction container, dropwise adding hydroxyl-terminated perfluoropolyether alcohol under stirring in an oil bath at 50-70 ℃ for 2-3h, heating the reaction system to 70-80 ℃ for condensation reflux reaction, wherein the condensation temperature is-10-0 ℃ until the pH value of the system is 4.5-6.5, and stopping heating;

s2: adding diethanolamine and an organic solvent 1 into the reaction system obtained in the step S1, performing addition reaction, rectifying, separating and purifying, collecting unreacted hydroxyl-terminated perfluoropolyether alcohol and transition fraction by normal pressure rectification, and collecting target products by reduced pressure rectification to obtain the fluorine-containing hydroxyl aminosilane.

4. The hyperbranched TPU nanofiber waterproof and moisture permeable film according to claim 3 wherein the unsaturated halosilane in S1 has the structure R-SiX ₃ Wherein R is an unsaturated alkylene group of C2-5, and X is F, cl, br, I.

5. The hyperbranched TPU nanofiber waterproof and moisture permeable membrane according to claim 3 wherein in S1, the hydroxyl terminated perfluoropolyether alcohol has the structure shown in formula I:

；

in the formula I, n=4-7, m=6-10; the hydroxyl-terminated perfluoropolyether alcohol has a number average molecular weight of 1000-1500.

6. The hyperbranched TPU nanofiber waterproof moisture-permeable membrane according to any one of claims 3-5 wherein the amount of unsaturated halosilane added to hydroxyl terminated perfluoropolyether alcohol satisfies-X: the molar ratio of the-OH is 1:1-1.5; the addition amount of the unsaturated halogenated silane and the diethanolamine satisfies the following conditions: -NH molar ratio of 0.8-1:1.

7. the hyperbranched TPU nanofiber waterproof and moisture-permeable membrane according to claim 3, wherein the organic solvent 1 in S2 is at least one of chloroform, dichloromethane, diethyl ether, toluene, methanol, ethanol, isopropanol.

8. A hyperbranched TPU nanofiber waterproof moisture-permeable membrane according to claim 3 characterized in that the normal pressure rectification in S2 collects a fraction of 75-80 ℃ and the reduced pressure distillation collects a fraction of 75-95 ℃.

9. The method for preparing the hyperbranched TPU nanofiber waterproof and moisture permeable membrane according to any one of claims 1 to 8, which is characterized by comprising the following steps: vacuum dehydrating the diisocyanate with a fluorohydroxy aminosilane according to-n=c=o: adding the mixture into a reactor filled with inert gas at the molar ratio of-OH=2:0.5-1, adding a catalyst accounting for 0.05-0.08wt% of the total reaction system mass after the organic solvent 2 is added for dissolution, stirring and reacting for 2-3h at 40-65 ℃, removing the organic solvent 2 by reduced pressure distillation, and spinning on a receiving substrate by adopting electrostatic spinning to form a film, thus obtaining the hyperbranched TPU nanofiber waterproof moisture-permeable film.

10. The hyperbranched TPU nanofiber waterproof and moisture-permeable membrane according to any one of claims 1 to 8 characterized by the use in the field of total heat exchangers.