CN111603941A - A kind of flat membrane element and preparation method thereof - Google Patents

Abstract

The invention relates to the field of ultra-microfiltration membranes, and discloses a flat plate membrane element, which comprises two layers of flat plate composite membranes superimposed on each other, and a plurality of intersecting hot-melt resins are arranged in the middle of the two layers of flat plate composite membranes. There is a small opening for water outlet around the superimposed two layers of flat composite membrane, and the rest are sealed and connected. The invention also discloses a preparation method of a flat film element, which comprises the following steps: S1. Coating the surfaces of two rolls of flat composite film with hot-melt resin. S2, extruding the two rolls of flat-plate composite film coated with hot-melt resin through double rolls, so that the hot-melt resin on the flat-plate composite film is crossed and fused into a whole in the shape of a "cross" to obtain an initial flat film element; S3, step S2 The initial flat membrane element prepared in 2 is cut into the required size, welded around it, and a small opening is left to discharge water, and the flat membrane element can be obtained. The flat membrane element and the preparation method thereof of the invention are simple and feasible, convenient for industrial production, and have good application prospect and economic value.

Description

A kind of flat membrane element and preparation method thereof

technical field

The invention relates to the field of ultra-microfiltration membranes, in particular to a flat membrane element and a preparation method thereof.

Background technique

Membrane separation technology has been widely used in many fields such as water treatment, and ultra-microfiltration membrane plays an important role in the field of membrane water treatment. According to the different shapes and component forms, ultra-microfiltration membranes can be divided into roll membranes, hollow membranes and flat membranes. Flat membrane has become one of the most important ultrafiltration products in the field of water treatment due to its good pressure resistance, high mechanical strength and high pollution tolerance.

The traditional flat membrane for water treatment generally has three layers, the outer layer is a flat composite membrane layer, the middle is a support plate, generally made of ABS material, and there is a lining mesh or lining cloth between the membrane layer and the supporting plate for diversion. This form of flat membrane is durable and stable, but due to the existence of the support plate and the guide mesh, the membrane element is bulky, inconvenient to install and transport, and at the same time, the production cost is higher than that of the hollow membrane and the roll membrane. , limiting its application. Therefore, more and more attention has been paid to the development of low-cost and convenient flat-panel membrane elements.

Patent CN 102512963 B discloses a flat membrane element for water treatment. The surface of the membrane element support plate is provided with a boss, and the adjacent membrane elements rely on the boss as a spacer support, which not only reduces membrane pollution, but also reduces the cost of the support plate by 30% . Patent CN 104014246 B discloses a double-diaphragm cross-flow filtration flat-plate membrane module, and a permeate diversion groove is arranged inside the support plate, which increases the effective area of the membrane and makes the replacement of the membrane simple and convenient. Patent CN 104226119 A discloses a split-type flat film, the support plate can be reused, and the cost of the flat film is reduced. The above patents are all focused on improving the support plate and water flow channel. In order to further reduce the cost to a level similar to that of the hollow membrane and rolled membrane, and to ensure that the performance of the membrane element is not reduced, and at the same time simplify the production process and improve the production efficiency, invented a new kind of The form of flat film is particularly important.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a flat membrane element and a preparation method thereof in order to overcome the deficiencies of the prior art. The filtration performance of the prepared flat membrane element is similar to that of the traditional flat membrane with a supporting plate, but the cost is only about one third of the cost. , and the production specifications of membrane elements are not limited by the size of the support plate and the welding machine, and can be adjusted at any time, which greatly simplifies the production equipment and improves the production efficiency.

To achieve the above object, the present invention adopts the following technical solutions:

The invention discloses a flat-plate film element, which comprises two layers of flat-plate composite films superimposed on each other, a plurality of mutually intersecting hot-melt resins are arranged in the middle of the two-layer flat-plate composite films; The small port for water outlet, and the rest are sealed connection.

Further, the flat composite film includes an organic polymer film layer and a non-woven support layer, the organic polymer film layer is attached to the non-woven support layer, and the hot-melt resin is arranged on the non-woven support layer.

Further, the hot-melt resin is ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer or acrylonitrile-butadiene-styrene copolymer.

Further, the crossed hot-melt resins are in the shape of a "cross".

Further, the hot-melt resin is at a parallel interval of 75-150mm and a vertical interval of 25-50mm.

Further, the length of the hot-melt resin is 50-100mm, the width of the hot-melt resin is 8-12mm, and the thickness of the hot-melt resin is 2.5-10mm.

The invention discloses a preparation method of a flat membrane element, which comprises the following steps:

S1. Pass two rolls of flat composite film through the rollers at the same speed, and coat the upper surface of one roll with vertical "1"-shaped hot-melt resin, and the upper surface of the other roll with horizontal and flat "1"-shaped hot-melt resin. .

S2. The two rolls of the flat composite film coated with the hot-melt resin are subjected to double-roll extrusion, so that the vertical hot-melt resin and the horizontal flat hot-melt resin on the flat composite film are cross-fused in a "cross" shape to obtain the initial flat film. element.

S3. Cut the initial flat membrane element prepared in step S2 into a required size, weld around it, and leave a small opening for water to obtain a flat membrane element.

Wherein, the flat composite film in the step S1 is two layers, one layer is an organic polymer film layer, the other layer is a non-woven support layer, and the organic polymer film layer is attached to the non-woven support layer; Hot melt resin is coated on the non-woven support layer.

Wherein, the hot melt resin in the step S1 is ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer or acrylonitrile-butadiene-styrene copolymer, which can be selected according to the non-woven material ( PP, PET, etc.) are different, use hot-melt resin materials that can be firmly bonded.

Further, the hot-melt resins in the step S1 are at a parallel interval of 75-150 mm and a vertical interval of 25-50 mm.

Further, in the step S1, the vertical "1"-shaped hot-melt resin is coated by the vertical hot-melt resin extruder, and the horizontal "1"-shaped hot-melt resin is coated by the horizontal hot-melt resin extruder; The hot-melt resin interval can be adjusted by the hot-melt resin extruder outlet interval.

Further, the length of the hot-melt resin is 50-100mm, the width of the hot-melt resin is 8-12mm, and the thickness of the hot-melt resin is 2.5-10mm.

Further, the temperature at which the hot-melt resin is extruded is 100-200°C, and the temperature at which the hot-melt resin reaches the double-roll extrusion is 50-100°C.

Further, the double rolls in the step S2 are circular stainless steel rolls, and the extrusion gap between the double rolls is 4-15 mm.

Further, the welding in step S3 is hot-melt welding or ultrasonic welding, which can be welded by a corresponding welding method according to different hot-melt resins, so as to ensure the excellent airtightness of the membrane element.

Further, the two rolls of flat-plate composite film are of the same material, and the hot-melt adhesive extruded on the two rolls of flat-plate composite film has the same material and temperature.

The benefits of the present invention are:

1. The flat membrane element prepared by the present invention is supported by the mechanical strength of the flat composite membrane itself, and does not need any support plate and other supports as support, thus greatly reducing the cost, and the hot melt resin is passed between the membranes. Welding together increases the mechanical strength of the membrane elements, and at the same time, the interval between the hot-melt resins is used as a water flow channel, and the membrane elements no longer need any lining cloth and lining net for diversion, thus further reducing the cost.

2. The preparation method of the flat membrane element of the present invention is simple and feasible, convenient for industrial production, and has good application prospect and economic value.

Description of drawings

Fig. 1 is the flow chart of the preparation method of the present invention.

Figure 2 is a flat plate composite film coated with a longitudinal hot-melt resin according to the present invention.

Figure 3 is a flat composite film coated with a horizontal hot-melt resin in the present invention.

Fig. 4 is the finished product of the flat membrane element of the present invention.

Explanation of main component symbols:

1-Flat composite film, 2-Roller, 3-Vertical "1" shape hot melt resin, 4-Horizontal flat "One" shape hot melt resin, 5-Round stainless steel roll, 6-Initial flat film element, 7- Flat film element, 8-small mouth, 9-vertical hot-melt resin extruder, 10-transverse hot-melt resin extruder.

Detailed ways

In order to make those skilled in the art better understand the technical solutions of the present invention, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

Example 1:

As shown in Figure 1-4, take two rolls of flat composite film 1 of the same material, the flat composite film 1 has two layers, one layer is an organic polymer film layer, the other layer is a non-woven support layer, and the organic polymer film The layer is attached to the non-woven support layer. One roll is placed at the front end of the vertical hot melt resin extruder 9, and the other roll is placed at the front end of the horizontal hot melt resin extruder 10. The two rolls of flat composite film 1 pass through the roller 2 at the same speed and then reach the extruder. , add ethylene-vinyl acetate copolymer into two hot-melt resin extruders, set the hot-melt temperature to 100 °C, isolate the air to heat and melt the ethylene-vinyl acetate copolymer into a liquid state, and then coat it on the flat plate in strip shape. On the non-woven support layer of the composite film 1, set the parameters of the hot-melt resin extruder, adjust the parallel interval of the hot-melt resin to 75mm, the vertical interval of 25mm, the length of 50mm, the width of 10mm, and the thickness of 2.5mm. The film of "1"-shaped hot-melt resin 3, as shown in Figure 2, is coated with a horizontal and flat "1"-shaped film of hot-melt resin 4, as shown in Figure 3, the two rolls of flat composite film 1 coated with hot-melt resin are passed through The roller 2 is sent to the extrusion place of the circular stainless steel roller 5, the hot melt resin is cooled to 50 ℃ in the air, and the extrusion gap of the circular stainless steel roller 5 is adjusted to 4mm. The molten resin is crossed and fused together in the shape of a "cross", so that the two rolls of flat composite film 1 are made into the initial flat film element 6, the initial flat film element 6 is cut, and then the four sides are welded with a hot-melt welding machine, leaving a small opening 8 to discharge water , the finished product of the flat membrane element 7 can be obtained, as shown in FIG. 4 . The total mass of the flat membrane element per square meter is only 500g, which is about one-third of the mass of the traditional flat membrane supported by the same area of the traditional support plate. about one-third.

Example 2:

As shown in Figure 1-4, take two rolls of flat composite film 1 of the same material, the flat composite film 1 has two layers, one layer is an organic polymer film layer, the other layer is a non-woven support layer, and the organic polymer film The layer is attached to the non-woven support layer. One roll is placed at the front end of the vertical hot melt resin extruder 9, and the other roll is placed at the front end of the horizontal hot melt resin extruder 10. The two rolls of flat composite film 1 pass through the roller 2 at the same speed and then reach the extruder. , add ethylene-vinyl alcohol copolymer into two hot-melt resin extruders, set the hot-melt temperature to 180 ℃, isolate the air to heat and melt the ethylene-vinyl alcohol copolymer into a liquid state, and then coat it on the flat composite film in strip shape On the non-woven support layer of 1, set the parameters of the hot-melt resin extruder, adjust the parallel interval of the hot-melt resin to 150mm, the vertical interval of 50mm, the length of 100mm, the width of 10mm, the thickness of 10mm, and the vertical "1". The film of the character-shaped hot-melt resin 3 is shown in FIG. 2 , the film of the horizontal and flat “one”-shaped hot-melt resin 4 is as shown in FIG. 3 , and the two rolls of flat-plate composite films 1 coated with the hot-melt resin are sent through the roller 2 . At the extrusion place of the circular stainless steel roller 5, the hot-melt resin is cooled to 90°C in the air, and the extrusion gap of the circular stainless steel roller 5 is adjusted to 15mm. The "X" characters are crossed and fused together, so that the two rolls of flat plate composite film 1 are made into the initial flat film element 6, the initial flat film element 6 is cut, and then the four sides are welded with a hot-melt welding machine, leaving a small opening 8 to get water out. The finished flat membrane element 7 is shown in Figure 4. The total mass of the flat membrane element per square meter is only 300g, which is about one-fifth of the mass of the traditional flat membrane supported by the same area of the traditional support plate. about one-third.

Example 3:

As shown in Figure 1-4, take two rolls of flat composite film 1 of the same material, the flat composite film 1 has two layers, one layer is an organic polymer film layer, the other layer is a non-woven support layer, and the organic polymer film The layer is attached to the non-woven support layer. One roll is placed at the front end of the vertical hot melt resin extruder 9, and the other roll is placed at the front end of the horizontal hot melt resin extruder 10. The two rolls of flat composite film 1 pass through the roller 2 at the same speed and then reach the extruder. , add acrylonitrile-butadiene-styrene copolymer into two hot-melt resin extruders, set the hot-melt temperature to 200 ℃, isolate the air to heat and melt the acrylonitrile-butadiene-styrene copolymer into a liquid state , and then coated in strips on the non-woven support layer of the flat composite film 1, set the parameters of the hot-melt resin extruder, adjust the parallel interval of the hot-melt resin to 100mm, the vertical interval of 40mm, the length of 80mm, the width of 10mm, the thickness of It is 5mm, and the film coated with the vertical "1"-shaped hot-melt resin 3 is shown in Figure 2, and the film coated with the horizontal and flat "1"-shaped hot-melt resin 4 is shown in Figure 3, and two rolls of hot-melt resin are coated. The flat composite film 1 is sent to the extrusion place of the circular stainless steel roller 5 through the roller 2. The hot-melt resin is cooled to 100 ℃ in the air, and the extrusion gap of the circular stainless steel roller 5 is adjusted to 8mm. After the circular stainless steel roller 5 is extruded Then, the two hot-melt resins are crossed and fused together in the shape of a "cross", so that the two rolls of flat plate composite film 1 are made into the initial flat film element 6, the initial flat film element 6 is cut, and then the four sides are welded with an ultrasonic welding machine, leaving A small port 8 flows out water, and the finished flat membrane element 7 can be obtained, as shown in FIG. 4 . The total mass of the flat membrane element per square meter is only 400g, which is about a quarter of the mass of the traditional flat membrane supported by the same area of the traditional support plate. about one-third.

To sum up, the flat membrane element prepared by the present invention is supported by the mechanical strength of the flat composite membrane itself, and does not need any supporting plate and other supports as support, thus greatly reducing the cost, and the membranes are heated and melted between the membranes. The resins are welded together to increase the mechanical strength of the membrane elements. At the same time, the interval between the hot-melt resins is used as a water flow channel. The membrane elements no longer need any lining cloth and lining net for diversion, thus further reducing the cost. In addition, the production specifications of membrane elements are not limited by the size of the support plate and the welding machine, and can be adjusted at any time, which greatly simplifies the production equipment and improves the production efficiency.

The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical scope disclosed by the present invention can easily think of changes or substitutions, All should be included within the protection scope of the present invention.

Claims (10)

1. a flat-plate film element, is characterized in that, comprises two-layer flat-plate composite films superimposed on each other, and is provided with some cross-cutting hot-melt resins in the middle of described two-layer flat-plate composite films; There is a small port for water outlet, and the rest are sealed and connected. 2 . The flat membrane element according to claim 1 , wherein the flat composite membrane comprises an organic polymer film layer and a non-woven support layer, and the organic polymer film layer is attached to the non-woven support layer. 3 . , the hot-melt resin is arranged on the non-woven support layer. 3 . The flat membrane element according to claim 1 , wherein the hot-melt resin is ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer or acrylonitrile-butadiene-styrene copolymer. 4 . 4 . The flat membrane element according to claim 1 , wherein the crossed hot-melt resins are in the shape of a "cross". 5 . 5 . The flat membrane element according to claim 4 , wherein the parallel interval of the hot-melt resin is 75-150 mm, and the vertical interval is 25-50 mm. 6 . 6 . The flat membrane element according to claim 1 , wherein the length of the hot-melt resin is 50-100 mm, the width of the hot-melt resin is 8-12 mm, and the thickness of the hot-melt resin is 2.5-10 mm. 7 . 7. a preparation method of flat membrane element, is characterized in that, comprises the steps: S1. Pass two rolls of flat composite film through the rollers at the same speed, and coat the upper surface of one roll with vertical "1"-shaped hot-melt resin, and the upper surface of the other roll with horizontal and flat "1"-shaped hot-melt resin. ; S2. The two rolls of the flat composite film coated with the hot-melt resin are subjected to double-roll extrusion, so that the vertical hot-melt resin and the horizontal flat hot-melt resin on the flat composite film are cross-fused in a "cross" shape to obtain the initial flat film. element; S3. Cut the initial flat membrane element prepared in step S2 into a required size, weld around it, and leave a small opening for water to obtain a flat membrane element. 8 . The method for preparing a flat membrane element according to claim 1 , wherein the flat composite membrane in the step S1 has two layers, one layer is an organic polymer film layer, and the other layer is a non-woven support layer. 9 . The organic polymer film layer is attached to the non-woven support layer; the hot-melt resin is coated on the non-woven support layer. 9 . The method for preparing a flat membrane element according to claim 1 , wherein the hot-melt resin in the step S1 is ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer or acrylonitrile-butanediol. 10 . ene-styrene copolymer. 10 . The method for preparing a flat membrane element according to claim 1 , wherein the hot-melt resin in the step S1 has a parallel interval of 75-150 mm and a vertical interval of 25-50 mm; 11 . In the step S1, a vertical "1"-shaped hot-melt resin is applied by a vertical hot-melt resin extruder, and a horizontal "1"-shaped hot-melt resin is applied by a horizontal hot-melt resin extruder; The interval of molten resin can be adjusted by the interval of the outlet of the hot-melt resin extruder; The length of the hot-melt resin is 50-100mm, the width of the hot-melt resin is 8-12mm, and the thickness of the hot-melt resin is 2.5-10mm; The temperature at which the hot-melt resin is extruded is 100-200°C, and the temperature at which the hot-melt resin reaches double-roll extrusion is 50-100°C; The double rolls in the step S2 are circular stainless steel rolls, and the extrusion gap between the double rolls is 4-15mm; The welding in step S3 is hot melt welding or ultrasonic welding; The two rolls of flat composite film are of the same material, and the hot melt adhesive extruded on the two rolls of flat composite film has the same material and temperature.

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