阅读说明：本技术 一种ectfe熔喷膜及其制备方法 (ECTFE melt-blown film and preparation method thereof ) 是由 刘慧� 吁苏云 代哲振 高林娜 张艳中 于 2019-11-26 设计创作，主要内容包括：本发明公开了一种ECTFE熔喷膜及其制备方法,所述熔喷膜由直径为0.1μm～5μm的超细纤维组成,至少60％的所述熔喷膜的孔径在0.3μm～0.7μm之间,小于20％的所述熔喷膜的孔径在0.1μm～0.3μm之间,小于20％的所述熔喷膜的孔径在0.7μm～1.0μm之间。本发明的熔喷膜具有拉伸强度大,断裂伸长率高,平均孔径小,过滤精度高,适用于耐高温、耐酸碱及耐腐蚀环境等优点。(The invention discloses an ECTFE melt-blown film and a preparation method thereof, wherein the melt-blown film consists of superfine fibers with the diameter of 0.1-5 mu m, the aperture of at least 60 percent of the melt-blown film is between 0.3-0.7 mu m, the aperture of less than 20 percent of the melt-blown film is between 0.1-0.3 mu m, and the aperture of less than 20 percent of the melt-blown film is between 0.7-1.0 mu m. The melt-blown film has the advantages of high tensile strength, high elongation at break, small average pore size, high filtering precision, suitability for high temperature resistance, acid and alkali resistance, corrosion resistance and the like.)

1. An ECTFE meltblown film characterized by: the melt-blown film consists of superfine fibers with the diameter of 0.1-5 mu m, the pore diameter of at least 60 percent of the melt-blown film is between 0.3-0.7 mu m, the pore diameter of less than 20 percent of the melt-blown film is between 0.1-0.3 mu m, and the pore diameter of less than 20 percent of the melt-blown film is between 0.7-1.0 mu m.

2. The ECTFE meltblown film according to claim 1, wherein: the melt-blown film consists of superfine fibers with the diameter of 0.5-1 mu m, the pore diameter of at least 75 percent of the melt-blown film is between 0.3-0.7 mu m, the pore diameter of less than 10 percent of the melt-blown film is between 0.1-0.3 mu m, the pore diameter of less than 10 percent of the melt-blown film is between 0.7-1.0 mu m, and the pore diameter of less than 5 percent of the melt-blown film exceeds 0.1-1.0 mu m.

3. The ECTFE meltblown film according to claim 1 or 2, characterized in that: the longitudinal tensile strength of the melt-blown film is 1.0MPa to 3.0MPa, and the longitudinal elongation at break is 10 percent to 60 percent; the transverse tensile strength of the melt-blown film is 0.5MPa to 2.0MPa, and the transverse elongation at break is 100 percent to 150 percent.

4. The ECTFE meltblown film according to any of the claims 1-3, characterized in that: the melt-blown film is prepared from ECTFE resin with the melt index of 400g/10 min-1500 g/10min (2.16kg, 275 ℃) and the melting temperature of 180 ℃ to 220 ℃.

5. The process for preparing ECTFE meltblown films according to any of claims 1 to 4 wherein: the preparation method comprises the following steps:

(1) heating the ECTFE resin into a melt by a double-screw extruder at the temperature of between 150 and 250 ℃;

(2) the ECTFE melt forms superfine fiber under the blowing of high-speed high-temperature air flow and is gathered on a net roller or a net forming curtain to form a fiber net;

(3) the fiber web is made into the ECTFE melt-blown film through self-bonding or hot pressing.

6. The method of preparing an ECTFE meltblown film according to claim 5, characterized in that: the temperature of the high-speed high-temperature airflow is 200-250 ℃, and the wind pressure is 0.05-0.5 MPa; the temperature of the net roller or the net forming curtain is 25-40 ℃.

7. The method of preparing ECTFE meltblown film according to claim 5 or 6, characterized in that: the distance between the net roller or the net forming curtain and the die lip for blowing the superfine fiber is 1 cm-5 cm.

8. The method of preparing ECTFE meltblown film according to claim 7, characterized in that: the distance between the net roller or the net forming curtain and the die lip for spraying and blowing the superfine fiber is 0.3 cm-1.0 cm.

9. The method of preparing an ECTFE meltblown film according to claim 5, characterized in that: in the step (3), the hot pressing temperature is 80-180 ℃, the hot pressing pressure is 0.05-5 MPa, and the hot pressing time is 0-20 s.

10. Use of ECTFE meltblown film according to any of claims 1-4 wherein: the melt-blown film is applied to the fields of water treatment, air filtration and dust removal, biomass separation and is used as an adsorption material or a thermal material.

Technical Field

The invention relates to the field of membrane materials, in particular to an ECTFE melt-blown membrane and a preparation method thereof.

Background

The ECTFE, namely the ethylene-chlorotrifluoroethylene copolymer, is an alternating copolymer of chlorotrifluoroethylene and ethylene close to 1:1, has the advantages of high mechanical strength, good heat resistance and chemical resistance, good weather resistance and the like, has alkali resistance reaching pH 14, has chemical reagent corrosion resistance equivalent to polytetrafluoroethylene, is particularly suitable for high-temperature and high-corrosion separation environments, has wide application prospect in the separation field, and is a potential ideal membrane material.

The melt-blown non-woven technology is one of polymer direct web-forming methods, and is characterized in that high polymer melt extruded by a screw extruder is subjected to extreme stretching by high-speed high-temperature air blowing or other means to form superfine fibers, then the superfine fibers are gathered on a web-forming roller or a web-forming curtain to form a web, and finally the web is reinforced by self-bonding to form the melt-blown non-woven fabric. The processing method of the high polymer has the characteristics of short process flow, high production efficiency and the like, at present, the melt-blown non-woven product takes polypropylene (PP), Polyester (PET), Polyamide (PA), Polyethylene (PE), Polyurethane (PU) and the like as raw materials, and other polymer melt-blown non-woven products are in the research and development stage, especially ECTFE melt-blown films.

The biggest technical problem of the ECTFE melt-blown membrane is that the membrane aperture is large, and the filtration precision can not meet the requirement; the processing temperature is higher, the prepared melt-blown yarn has larger diameter (the minimum is 2-3 mu m), the mechanical property is poorer, and the longitudinal elongation at break is only about 5 percent. There is no report in the prior art to solve the above technical problem.

Disclosure of Invention

In order to solve the technical problems, the invention provides the ECTFE melt-spraying membrane which has the advantages of thin diameter of fiber filaments, uniform membrane pore size distribution, high tensile strength, high elongation at break and high filtering precision, and is suitable for high temperature resistance, acid and alkali resistance and corrosion resistance.

The purpose of the invention is realized by the following technical scheme:

an ECTFE meltblown film comprising ultra fine fibers having a diameter of 0.1 to 5 μm, at least 60% of the meltblown film having a pore size between 0.3 to 0.7 μm, less than 20% of the meltblown film having a pore size between 0.1 to 0.3 μm, less than 20% of the meltblown film having a pore size between 0.7 to 1.0 μm.

Preferably, the meltblown film is composed of superfine fibers with the diameter of 0.5-1 μm, the pore diameter of at least 75% of the meltblown film is between 0.3-0.7 μm, the pore diameter of less than 10% of the meltblown film is between 0.1-0.3 μm, the pore diameter of less than 10% of the meltblown film is between 0.7-1.0 μm, and the pore diameter of less than 5% of the meltblown film exceeds 0.1-1.0 μm.

The longitudinal tensile strength of the melt-blown film is 1.0MPa to 3.0MPa, and the longitudinal elongation at break is 10 percent to 60 percent; the transverse tensile strength of the melt-blown film is 0.5MPa to 2.0MPa, and the transverse elongation at break is 100 percent to 150 percent. Preferably, the longitudinal tensile strength of the melt-blown film is 1.5MPa to 2.5MPa, and the longitudinal elongation at break is 30% to 50%; the transverse tensile strength of the melt-blown film is 1.0MPa to 1.5MPa, and the transverse elongation at break is 120 percent to 130 percent.

The melt-blown film is prepared from ECTFE resin with the melt index of 400g/10 min-1500 g/10min (2.16kg, 275 ℃) and the melting temperature of 180 ℃ to 220 ℃. Preferably, the ECTFE resin has a melt index of 600g/10min to 1000g/10min (2.16kg, 275 ℃) and a melting temperature of 195 ℃ to 205 ℃.

The invention also provides a preparation method of the ECTFE melt-blown film, which has the advantages of short process flow and high production efficiency, and comprises the following specific steps:

(1) heating the ECTFE resin into a melt by a double-screw extruder at the temperature of between 150 and 250 ℃;

(2) the ECTFE melt forms superfine fiber under the blowing of high-speed high-temperature air flow and is gathered on a net roller or a net forming curtain to form a fiber net;

(3) the fiber web is made into the ECTFE melt-blown film through self-bonding or hot pressing.

According to the above ECTFE melt-blown film preparation method, preferably, the temperature of the high-speed high-temperature air flow is 200-250 ℃, and the air pressure is 0.05-0.5 MPa; the temperature of the net roller or the net forming curtain is 25-40 ℃.

According to the above-mentioned ECTFE meltblown film production method, preferably, the distance between the mesh roll or curtain and the die lip for blowing the microfibers is 1cm to 5 cm. Further preferably, the distance between the net roller or the net forming curtain and the die lip for spraying and blowing the superfine fibers is 0.3 cm-1.0 cm.

Under the condition of a certain hot air flow velocity, the larger the distance between the net roller and the die lip is, the longer the time for the melt spinning yarns to reach the net roller from the die lip is, and the longer the time is, the more obvious the temperature reduction is. After the melt spinning temperature is reduced, the melt spinning is not easy to be drawn and stretched by hot air to become thin, so the diameter of the melt spinning is seriously influenced by the distance between the net roller and the die lip, namely the larger the distance between the net roller and the die lip is, the thicker the diameter of the melt spinning is.

According to the preparation method of the ECTFE melt-blown film, in the step (3), the hot pressing temperature is 80-180 ℃, the hot pressing pressure is 0.05-5 MPa, and the hot pressing time is 0-20 s.

The invention also provides the use of ECTFE meltblown film as claimed in any one of claims 1 to 4 in the fields of application of said meltblown film comprising:

1. the field of water treatment, such as domestic sewage treatment, industrial wastewater treatment and the like;

2. the field of filtration and dust removal, such as air dust removal, PM2.5 filtration and the like;

3. the field of biomass separation, such as protein separation and the like;

4. as an adsorbent material, such as a mask, etc.;

5. can be used as thermal insulation material, such as inner bladder of jacket.

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

1. according to the invention, the ECTFE meltblown film is prepared by a meltblown method, the melting temperature of the ECTFE resin used as a raw material is 180-220 ℃, the melting temperature of the conventional ECTFE resin is higher than 240 ℃, on the basis, the meltblown film prepared by the method is composed of superfine fibers of 0.5-1 mu m, the pore diameter distribution is uniform, the average pore diameter is small, and at least 75% of the meltblown film has the pore diameter of 0.3-0.7 mu m, so that the meltblown film is large in tensile strength, high in elongation at break and high in filtering precision, and is suitable for harsh environments such as high temperature resistance, acid and alkali resistance, corrosion resistance and the like.

2. In the preparation process of the ECTFE meltblown film, the distance between the mesh roller or the mesh forming curtain and the die lip for blowing the superfine fibers is controlled to be 1 cm-5 cm, so that the meltblown film has thinner meltblown filaments, and the average pore size of the prepared meltblown film is smaller.

3. In the preparation process of the ECTFE meltblown film, the tensile strength and elongation at break of the meltblown film are greatly improved by controlling the hot pressing process parameters.

Drawings

FIG. 1 is a schematic view of a melt blowing process of the present invention;

FIG. 2 shows the front structure of ECTFE meltblown film of example 1 of the present invention;

FIG. 3 is an enlarged view of the ECTFE meltblown film of example 1.

Detailed Description

The present invention is further illustrated by the following examples, which are not intended to limit the invention to these embodiments. It will be appreciated by those skilled in the art that the present invention encompasses all alternatives, modifications and equivalents as may be included within the scope of the claims.

Example 1

The ECTFE resin having a melt temperature of 195 deg.C (melt index of 600g/10min, 2.16kg, 275 deg.C) was melt-processed in a twin-screw extruder at a melt processing temperature of 200 deg.C. The temperature of hot air of high-speed high-temperature air flow is 230 ℃, the pressure of the hot air is 0.1MPa, the temperature of a net roller is 30 ℃, the distance between a die lip and the net roller is 2cm, and the diameter of the obtained ECTFE superfine fiber is 1.0 mu m.

And during hot pressing, the hot pressing temperature is 100 ℃, the hot pressing pressure is 0.05MPa, and the hot pressing time is 10 s.

At least 75% of the prepared melt-blown film has the pore diameter between 0.3 and 0.7 mu m, less than 10% of the prepared melt-blown film has the pore diameter between 0.1 and 0.3 mu m, less than 10% of the prepared melt-blown film has the pore diameter between 0.7 and 1.0 mu m, and less than 5% of the prepared melt-blown film has the pore diameter exceeding 0.1 to 1.0 mu m.

The longitudinal tensile strength of the prepared melt-blown film is 1.52MPa, and the longitudinal elongation at break is 15%; the melt-blown film had a transverse tensile strength of 0.87MPa and a transverse elongation at break of 101%.

Example 2

The operation of this example is the same as example 1 except that: the temperature of the mesh roller is 40 ℃, the distance between the die lip and the mesh roller is 1cm, and the diameter of the obtained ECTFE superfine fiber is 0.5 mu m.

And during hot pressing, the hot pressing temperature is 100 ℃, the hot pressing pressure is 0.05MPa, and the hot pressing time is 10 s. At least 80% of the meltblown films have a pore size between 0.3 μm and 0.7 μm, 10% of the meltblown films have a pore size between 0.1 μm and 0.3 μm, 5% of the meltblown films have a pore size between 0.7 μm and 1.0 μm, and 5% of the meltblown films have a pore size exceeding 0.1 μm and 1.0 μm. The longitudinal tensile strength of the prepared melt-blown film is 2.08MPa, and the longitudinal elongation at break is 50%; the transverse tensile strength of the meltblown film was 1.50MPa and the transverse elongation at break was 108%.

Example 3

The operation of this example is the same as example 1 except that: the ECTFE resin having a melt temperature of 180 deg.C (melt index of 600g/10min, 2.16kg, 275 deg.C) was melt-processed in a twin-screw extruder at a melt processing temperature of 185 deg.C. The diameter of the ECTFE ultrafine fibers obtained was 0.4. mu.m.

The prepared 85 percent of the melt-blown film has the aperture between 0.3 and 0.7 mu m, the aperture of less than 5 percent of the melt-blown film is between 0.1 and 0.3 mu m, the aperture of less than 5 percent of the melt-blown film is between 0.7 and 1.0 mu m, and the aperture of less than 5 percent of the melt-blown film exceeds 0.1 to 1.0 mu m.

The longitudinal tensile strength of the prepared melt-blown film is 2.13MPa, and the longitudinal elongation at break is 53%; the melt-blown film had a transverse tensile strength of 1.53MPa and a transverse elongation at break of 110%.

Example 4

The operation of this example is the same as example 1 except that: the ECTFE resin (melt index 600g/10min, 2.16kg, 275 ℃ C.) having a melt temperature of 220 ℃ was melt-processed in a twin-screw extruder at a melt processing temperature of 225 ℃. The diameter of the ECTFE ultrafine fibers obtained was 1.2. mu.m.

At least 70% of the prepared melt-blown film has the pore diameter of 0.3-0.7 mu m, less than 15% of the prepared melt-blown film has the pore diameter of 0.1-0.3 mu m, less than 10% of the prepared melt-blown film has the pore diameter of 0.7-1.0 mu m, and less than 5% of the prepared melt-blown film has the pore diameter exceeding 0.1-1.0 mu m.

The longitudinal tensile strength of the prepared melt-blown film is 1.48MPa, and the longitudinal elongation at break is 12%; the transverse tensile strength of the melt-blown film was 0.75MPa, and the transverse elongation at break was 90%.

Example 5

The operation of this example is the same as example 2 except that: and during hot pressing, the hot pressing temperature is 120 ℃, the hot pressing pressure is 2.0MPa, and the hot pressing time is 20 s.

At least 75% of the prepared melt-blown film has the pore diameter between 0.3 and 0.7 mu m, less than 10% of the prepared melt-blown film has the pore diameter between 0.1 and 0.3 mu m, less than 10% of the prepared melt-blown film has the pore diameter between 0.7 and 1.0 mu m, and less than 5% of the prepared melt-blown film has the pore diameter exceeding 0.1 to 1.0 mu m.

The longitudinal tensile strength of the prepared melt-blown film is 1.05MPa, and the longitudinal elongation at break is 45%; the meltblown film had a transverse tensile strength of 1.34MPa and a transverse elongation at break of 130%.

Comparative example 1

The comparative example was conducted as in example 1 except that: the ECTFE resin (melt index 600g/10min, 2.16kg, 275 ℃ C.) having a melt temperature of 240 ℃ was melt-processed in a twin-screw extruder at a melt processing temperature of 250 ℃. The diameter of the ECTFE ultrafine fibers obtained was 2.2. mu.m.

At least 65% of the prepared melt-blown film has the pore diameter of 0.3-0.7 mu m, less than 15% of the prepared melt-blown film has the pore diameter of 0.1-0.3 mu m, less than 15% of the prepared melt-blown film has the pore diameter of 0.7-1.0 mu m, and less than 5% of the prepared melt-blown film has the pore diameter exceeding 0.1-1.0 mu m.

The longitudinal tensile strength of the prepared melt-blown film is 1.40MPa, and the longitudinal elongation at break is 11%; the melt blown film had a transverse tensile strength of 0.73MPa and a transverse elongation at break of 75%. Comparative example 2

The comparative example was conducted as in example 1 except that: the temperature of the mesh roller is 40 ℃, the distance between the die lip and the mesh roller is 10cm, and the diameter of the obtained ECTFE superfine fiber is 3.5 mu m.

At least 60% of the prepared melt-blown film has the pore diameter of 0.3-0.7 μm, less than 15% of the prepared melt-blown film has the pore diameter of 0.1-0.3 μm, less than 20% of the prepared melt-blown film has the pore diameter of 0.7-1.0 μm, and less than 5% of the prepared melt-blown film has the pore diameter exceeding 0.1-1.0 μm.

The longitudinal tensile strength of the prepared melt-blown film is 1.38MPa, and the longitudinal elongation at break is 10%; the melt-blown film had a transverse tensile strength of 0.70MPa and a transverse elongation at break of 60%. Comparative example 3

The operation of this comparative example is the same as comparative example 1 except that: the temperature of the mesh roller is 40 ℃, the distance between the die lip and the mesh roller is 15cm, and the diameter of the obtained ECTFE superfine fiber is 5.2 mu m.

At least 50% of the prepared melt-blown film has the pore diameter of 0.3-0.7 mu m, less than 25% of the prepared melt-blown film has the pore diameter of 0.1-0.3 mu m, less than 20% of the prepared melt-blown film has the pore diameter of 0.7-1.0 mu m, and less than 5% of the prepared melt-blown film has the pore diameter exceeding 0.1-1.0 mu m.

The longitudinal tensile strength of the prepared melt-blown film is 1.25MPa, and the longitudinal elongation at break is 8%; the transverse tensile strength of the melt-blown film was 0.85MPa, and the transverse elongation at break was 50%.