阅读说明：本技术 一种聚氨酯湿法调节超纤基布膜微孔的新方法 (Novel method for adjusting micropores of microfiber base cloth membrane by polyurethane wet method ) 是由 孟刘邦 徐华伟 张继刚 高柄棋 陈东 倪雅军 于 2021-01-11 设计创作，主要内容包括：本发明公开了一种聚氨酯湿法调节超纤基布膜微孔的新方法,属于湿法制备超纤基布技术领域。具体实施方式为将聚氨酯浆料涂敷在超纤无纺布上,然后将其放入DMF/甲苯的混合液凝固浴中凝固,凝固后送入抽出槽进行甲苯减量抽出；上油处理,并在干燥箱中烘干,得到膜微孔均匀的超纤贝斯基布。本发明通过甲苯与DMF两体系间相互扩散速率的不同来调控聚氨酯凝固的速度及孔结构,从而节省了传统凝固调节剂的使用,改善了超纤基布膜的微孔结构,本发明制作的超纤基布不仅微孔结构均匀,连通性好,而且具有良好的透气性和舒适性；实现了降低能耗的目的。(The invention discloses a novel method for adjusting micropores of a microfiber base cloth membrane by a polyurethane wet method, and belongs to the technical field of microfiber base cloth preparation by a wet method. The specific implementation mode is that polyurethane slurry is coated on microfiber non-woven fabric, then the microfiber non-woven fabric is put into a mixed solution of DMF/toluene for coagulation, and after coagulation, the microfiber non-woven fabric is sent into a drawing tank for toluene reduction and drawing; oiling and drying in a drying box to obtain the microfiber Beth base cloth with uniform film micropores. The invention regulates and controls the solidification speed and the pore structure of polyurethane through the difference of the mutual diffusion rate between the toluene and the DMF, thereby saving the use of the traditional solidification regulator and improving the micropore structure of the microfiber base cloth membrane; the purpose of reducing energy consumption is achieved.)

1. A new method for adjusting the micropores of a microfiber base cloth membrane by a polyurethane wet method is characterized by comprising the following steps:

1) selecting a super-fiber non-woven fabric, and coating the polyurethane slurry on the super-fiber non-woven fabric;

2) putting the super-fiber non-woven fabric treated in the step 1) into a mixed solution of DMF (dimethyl formamide)/toluene for coagulation in a coagulation bath, and then sending the super-fiber non-woven fabric into a drawing tank for toluene reduction and drawing;

3) oiling the microfiber non-woven fabric processed in the step 2), and placing the microfiber non-woven fabric in a drying oven to be dried to obtain microfiber Beth base fabric with uniform membrane micropores.

2. The method for adjusting the micropores of the microfiber substrate cloth membrane by using the wet method of polyurethane as claimed in claim 1, wherein the solvent of the polyurethane slurry in the step 1) is DMF, the mass concentration of the polyurethane is between 5% and 30%, and the modulus of the polyurethane is between 20% and 250.

3. The new method for adjusting the micropores of the microfiber-based cloth membrane by using the wet method of polyurethane according to claim 1, wherein the composition ratio of the DMF/toluene mixed solution in the step 2) is 30-95% by mass of toluene in the mixed solution.

4. The method for adjusting the micropores of the microfiber base cloth membrane by using the wet method of polyurethane according to claim 1, wherein the temperature of the coagulation bath in the step 2) is 20-60 ℃.

Technical Field

The invention belongs to the technical field of wet preparation of microfiber base cloth, and particularly relates to a novel method for adjusting micropores of a microfiber base cloth membrane by a polyurethane wet method.

Background

The microfiber synthetic leather is obtained by dry surfacing or post finishing on a base cloth of a polyurethane microporous coating, the base cloth is generally prepared by soaking microfiber non-woven fabric in polyurethane slurry by a wet method, and then solidifying, washing, pumping out, oiling, drying and the like, so that the polyurethane characteristic in the non-woven fabric has great influence on the microfiber synthetic leather, the polyurethane in the non-woven fabric is mainly obtained by adopting wet method phase separation solidification film forming at present, the phase separation environment of the wet method film forming has great influence on the physical property of the polyurethane in the non-woven fabric, the wet method film forming is mainly carried out in non-solvent water at present, polyurethane molecules are gradually aggregated into gel from the solution through mutual diffusion of water and DMF in the polyurethane slurry, and finally the film is separated out, however, the DMF is extracted from the slurry by the water at a higher speed, so that the surface solidification speed of the wet method film is higher, and further solidification of the inner layer of the polyurethane film is influenced, the wet process polyurethane film has poor surface and inner uniformity, especially the difference of the sizes and the distribution of holes on the surface layer and the inner layer is large, the surface layer is compact and has few holes, the inner layer is thick and uneven finger-shaped holes, the smoothness of inner and outer layer pore passages is influenced, meanwhile, the thick and uneven finger-shaped holes are easy to become stress concentration points on the mechanical property and become the weakest link when stressed, thereby reducing the physical property of the synthetic leather₂For an O coagulation bath system, the energy consumption for recycling DMF is high, the energy consumption for recycling DMF in the coagulation bath is reduced under the condition that the nation advocates economical economy, and the method has positive contribution to energy conservation and emission reduction.

Disclosure of Invention

The invention aims to provide a novel method for adjusting the micropores of a microfiber base cloth membrane by a polyurethane wet method, so as to solve the problem of uneven shape, size and distribution of the micropores of the microfiber synthetic leather membrane and simultaneously realize the reduction of DMF (dimethyl formamide) recovery energy consumption in a coagulating bath.

In order to achieve the purpose, the following technical scheme is provided:

a new method for adjusting the micropores of a microfiber base cloth membrane by a polyurethane wet method is characterized by comprising the following steps:

1) selecting a super-fiber non-woven fabric, and coating the polyurethane slurry on the super-fiber non-woven fabric;

2) putting the super-fiber non-woven fabric treated in the step 1) into a mixed solution of DMF (dimethyl formamide)/toluene for coagulation in a coagulation bath, and then sending the super-fiber non-woven fabric into a drawing tank for toluene reduction and drawing;

3) oiling the microfiber non-woven fabric processed in the step 2), and placing the microfiber non-woven fabric in a drying oven to be dried to obtain microfiber Beth base fabric with uniform membrane micropores.

Further, the solvent of the polyurethane slurry in the step 1) is DMF, the mass concentration of the polyurethane is between 5% and 30%, and the modulus of the polyurethane is between 20% and 250.

Further, the composition ratio of the DMF/toluene mixed solution in the step 2) is 30-95% of toluene in mass percent of the mixed solution.

Further, the temperature of the coagulating bath in the step 2) is 20-60 ℃.

Compared with the prior art, the invention has the beneficial effects that:

1) when the microfiber non-woven fabric coated with the polyurethane slurry is immersed in DMF/toluene solidification liquid for solidification, the DMF in the polyurethane slurry is gradually replaced by the toluene in the solidification liquid, and the solidification speed and the pore structure of the polyurethane are regulated and controlled through the difference of the mutual diffusion rates of the toluene and the DMF, so that the use of the traditional solidification regulator is saved, and the micropore structure of a microfiber base fabric membrane is improved;

2) compared with the conventional DMF/H₂DMF and H in O coagulation bath₂O separation, the DMF in the DMF/toluene coagulating bath is separated from the toluene, the energy consumption is saved, and the invention adoptsDMF/toluene is used as coagulating bath solution to reduce energy consumption.

Drawings

FIG. 1 is a SEM image of a cross-section of a microfiber Besse base cloth prepared by example 1;

FIG. 2 is a SEM image of a cross-section of a microfiber Besse base cloth prepared by example 2;

FIG. 3 is a SEM image of a cross-section of a microfiber Besse base cloth prepared by example 3;

FIG. 4 is a SEM image of a cross-section of a microfiber Besse base cloth prepared by example 4.

Detailed Description

The invention will be further described with reference to the following examples and the accompanying drawings, but the scope of the invention is not limited thereto.

Example 1

Selecting a PA6/PE sea-island type microfiber non-woven fabric block with the thickness of 1.0mm, coating polyurethane slurry with the mass concentration of 15% and the modulus of 60 on the microfiber non-woven fabric, then completely solidifying the microfiber non-woven fabric block in a solidification bath of DMF/water with the DMF content of 40% at 45 ℃, sending the microfiber non-woven fabric block into a drawing tank for toluene decrement drawing, then oiling the microfiber non-woven fabric block, and drying the microfiber non-woven fabric block in a drying box to obtain the final microfiber Bass fabric block, wherein the cross section SEM image of the microfiber Bessel fabric block is shown in figure 1, the micropore shape of a polyurethane film is observed, and the inner pore diameter and the outer pore diameter of the microfiber non.

Example 2

Selecting a PA6/PE sea-island type microfiber non-woven fabric block with the thickness of 1.0mm, coating polyurethane slurry with the concentration of 5% and the modulus of 250 on the microfiber non-woven fabric block, completely solidifying the microfiber non-woven fabric block in a solidification bath of a DMF/toluene mixed solution with the toluene content of 30%, conveying the microfiber non-woven fabric block into a drawing tank for toluene decrement drawing, oiling the microfiber non-woven fabric block, and drying the microfiber non-woven fabric block in a drying box to obtain microfiber Bass fabric, wherein the cross section SEM image of the microfiber Bess fabric block is shown in figure 2, and the micropore shape of a membrane is observed and is of a uniform pore structure inside and outside.

Example 3

Selecting a PA6/PE sea-island type microfiber non-woven fabric block with the thickness of 1.5mm, coating polyurethane slurry with the concentration of 30% and the modulus of 20 on the microfiber non-woven fabric block, completely solidifying the microfiber non-woven fabric block in a solidification bath of a DMF (dimethyl formamide)/toluene mixed solution with the toluene content of 95%, conveying the microfiber non-woven fabric block into a drawing tank for toluene decrement drawing, oiling the microfiber non-woven fabric block, drying the microfiber non-woven fabric block in a drying box to obtain microfiber Bass fabric, wherein the cross section SEM image of the microfiber Bess fabric block is shown in figure 3, and the micropore shape of polyurethane is observed and has a uniform pore structure inside and outside.

Example 4

Selecting a PA6/PE sea-island type microfiber non-woven fabric block with the thickness of 0.8mm, coating polyurethane slurry with the concentration of 25% and the modulus of 100 on the microfiber non-woven fabric block, completely solidifying the microfiber non-woven fabric block in a solidification bath of a DMF/toluene mixed solution with the toluene content of 80%, conveying the microfiber non-woven fabric block into a drawing tank for toluene decrement drawing, oiling the microfiber non-woven fabric block, drying the microfiber non-woven fabric block in a drying box to obtain microfiber Bass fabric, observing the micropore shape of polyurethane to form a pore structure with uniform inside and outside, wherein the cross section SEM image of the microfiber Bass fabric block is shown in figure 4.