Production method of toughened polyurethane film

A polyurethane film and polyurethane technology, which is applied in the field of preparation of toughened polyurethane film, can solve the problems of not giving full play to the structure and performance of the polyurethane body material, the effect of polyurethane toughening is not significant enough, and the toughening range of polyurethane film is not large enough, etc.

Active Publication Date: 2019-09-13
WUHAN TEXTILE UNIV
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  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

Although this method uses ammonium salt as a coagulation bath, the micro-crosslinked structure formed in the form of hydrogen bonds between the ammonium salt molecules in the polyurethane film after film formation and the amorphous region molecules in the polyurethane, or in the pores of the polyurethane film The formation of nano-needle structure and nano-spherical structure can increase the tensile stress and strain of the polyurethane film at the same time, but its disadvantage is that on the one hand, the toughening range of the polyurethane film prepared by this method is not large enough; The polyurethane film prepared by the method introduces the second phase material, not a single-component pure polyurethane film
However, its shortcoming is that the toughening effect of this method on polyurethane is not sign

Method used

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  • Production method of toughened polyurethane film

Examples

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Example Embodiment

[0037] See figure 1 As shown, the present invention provides a method for preparing a toughened polyurethane film, which includes the following steps:

[0038] S1, the preparation of the casting liquid; the poor solvent of polyurethane, N,N-dimethylformamide and solvents with lower polarity than N,N-dimethylformamide are compounded into a ternary mixed solvent. Among them, the polyurethane The mass fraction of poor solvent is 5% to 45%; the mass fraction of N,N-dimethylformamide is 30% to 90%; the mass fraction of solvents with lower polarity than N,N-dimethylformamide is 5%~30%;

[0039] Then the polyurethane prepolymer with a mass fraction ratio of 5%:95%-40%:60% and a ternary mixed solvent are mechanically stirred and then vacuum defoamed to prepare a polyurethane film casting liquid; wherein the stirring temperature is 20-45 ℃, the stirring rate is 500~4000r / min, and the stirring time is 0.5~5h;

[0040] S2, preparation of coagulation bath;

[0041] S3, scraping the polyurethane...

Example Embodiment

[0054] Example one

[0055] Toluene, N,N-dimethylformamide and dioxane with a mass fraction ratio of 5%:85%:10% are mixed into a ternary mixed solvent, and the mass fraction ratio is 10%:90% The polyether polyurethane prepolymer and the ternary mixed solvent are mechanically stirred for 2 hours and then vacuum defoamed to prepare a polyurethane casting liquid. Among them, the stirring temperature is 30°C, and the stirring rate is 800r / min.

[0056] Mixing deionized water with a mass fraction ratio of 99%:1% and ethanol, and mixing them evenly to prepare a coagulation bath. Among them, the conductivity of deionized water is 16MΩ·cm, and the temperature of the coagulation bath solution is 20°C.

[0057] Scrape the prepared polyurethane casting liquid on the PTFE mold, immediately immerse it in the coagulation bath for 4 hours after heat treatment for 60 seconds, and then take it out, then place it in a 30°C drying oven for solvent evaporation treatment for 48 hours, and finally, in a...

Example

[0062] Example 2 to Example 8

[0063] The difference between Example 2 to Example 8 and Example 1 is only: in the ternary mixed solvent, the mass fraction ratios of toluene, N,N-dimethylformamide and dioxane are different, and the other steps are the same as those in Example 1. The mass fractions of toluene, N,N-dimethylformamide and dioxane in Example 2 to Example 8 are basically the same and are not repeated here;

[0064]

[0065] The process of preparing polyurethane film by traditional immersion precipitation method is: preparation of casting film; dissolving polyurethane in N,N-dimethylformamide, mechanically stirring and vacuum defoaming to prepare polyurethane film casting solution; The casting liquid is scraped on the mold, and then the mold containing the casting liquid is immersed in a water coagulation bath for about 2 hours, and then the mold is taken out and dried to obtain a polyurethane film.

[0066] Table 1 shows the increase in mechanical properties of the toughe...

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Abstract

The invention provides a production method of a toughened polyurethane film. The production method of the toughened polyurethane film comprises the following steps of (1) producing a casting solution,wherein a poor solvent of polyurethane, N,N-dimethylformamide and a solvent with polarity lower than that of the N,N-dimethylformamide are mixed to form a ternary mixed solvent, and then vacuum defoamation is conducted after a polyurethane prepolymer and the ternary mixed solvent are stirred evenly by a machine so as to produce the polyurethane casting solution; (2) producing a coagulation bath;(3) conducting blade coating on the polyurethane casting solution to coat a mold with the polyurethane casting solution; (4) conducting thermal treatment on the mold in an environment at 40-80 DEG C for 30-60 s; (5) sequentially conducting immersion precipitation and solvent evaporation treatment on the mold; and (6) conducting thermal treatment on a polyurethane film at 80-100 DEG C to obtain thetoughened polyurethane film. According to the production method of the toughened polyurethane film, the poor solvent of the polyurethane, the N,N-dimethylformamide and the solvent with polarity lowerthan that of the N,N-dimethylformamide are adopted, and are mixed to form the ternary mixed solvent system, and the polyurethane film formation speed and a distribution mode of polyurethane moleculechains are improved, so that the polyurethane film excellent in mechanical performance is obtained.

Description

technical field [0001] The invention relates to the technical field of polymer film preparation, in particular to a method for preparing a toughened polyurethane film. Background technique [0002] Polyurethane is a block polymer composed of alternating soft and hard segments. The soft segment is in a highly elastic state at room temperature and can produce large tensile deformation, while the hard segment provides nodes for the elongation and deformation of the soft segment. The unique chemical structure of polyurethane makes it have excellent properties such as high elasticity, abrasion resistance, solvent resistance, water resistance, fatigue resistance and aging resistance, so it is widely used in textile, national defense, transportation, sports, construction, medical, Fields such as machinery and energy occupy a very important position in the national economy. [0003] At present, the commonly used methods for preparing high-tough polyurethane films include chemical m...

Claims

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Application Information

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IPC IPC(8): C08J5/18C08L75/04
CPCC08J5/18C08J2375/04
Inventor 刘欣张春华王云吕佩李晨张科徐卫林
Owner WUHAN TEXTILE UNIV
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