阅读说明：本技术 一种透气膜的吹制方法 (Blowing method of breathable film ) 是由 刘文艺 岳宇 蹇刚 岳净夫 李建平 于 2020-12-18 设计创作，主要内容包括：本发明提供了一种透气膜的吹制方法,其包括以下步骤,原料混料、吹膜成型、风环冷却、薄膜定型,得到成品透气膜。本发明通过改善风环冷却和薄膜定型的条件,以初步平衡透气膜的抗静水压性能、透气性和透湿性,并通过电晕处理进一步提高透气膜的抗静水压性能,在兼顾高效的基础上,实现了透气膜的抗静水压性能、透气性和透湿性的共同提高。(The invention provides a method for blowing a breathable film, which comprises the following steps of mixing raw materials, blowing the film for forming, cooling an air ring, and shaping the film to obtain a finished breathable film. According to the invention, the hydrostatic pressure resistance, the air permeability and the moisture permeability of the breathable film are initially balanced by improving the conditions of air ring cooling and film shaping, the hydrostatic pressure resistance of the breathable film is further improved by corona treatment, and the hydrostatic pressure resistance, the air permeability and the moisture permeability of the breathable film are jointly improved on the basis of high efficiency.)

1. A method of blowing a breathable film, comprising: comprises the following steps of (a) carrying out,

s1, mixing raw materials, weighing the raw materials according to parts by weight, uniformly mixing the calcium carbonate inorganic filler, the polyethylene base material and the mixing auxiliary agent, and performing melt extrusion to obtain a resin material;

s2, performing film blowing molding, namely performing film blowing molding on the resin material prepared in the S1 on a single-screw film blowing machine to obtain a tubular film;

s3, cooling by wind rings, namely, penetrating the tubular film of the S2 through a double-wind-ring film cooling device, and expanding and cooling the tubular film by a gas medium introduced into the space in the tubular film;

s4 film shaping, namely sequentially clamping the S3 tubular film by a herringbone plate and folding and transiting the tubular film by a transition roller, then preheating the film to 70-90 ℃, and stretching and heat-shaping the film to obtain a semi-finished product of the breathable film;

and S5, performing corona treatment, namely allowing the semi-finished product of the breathable film obtained in the step S4 to pass through a space between polar plates with high voltage, bombarding the outer side surface of the semi-finished product of the breathable film by high voltage, and then cutting edges and rolling to obtain the finished breathable film.

2. A method of blowing a breathable film according to claim 1, wherein: in S1, the method includes the steps of,

s11, sequentially adding 120 parts of superfine heavy calcium carbonate calcium titanate, 50 parts of silicon dioxide substrate single-crystal single-layer graphene, 30 parts of nano titanium dioxide loaded silver ions and 0.5 part of polyoxyethylene ether-40 hydrogenated castor oil into a stirrer, and uniformly stirring to obtain 200.5 parts of calcium carbonate inorganic filler;

s12, under the stirring state, sequentially adding 20 parts of metallocene linear low-density polyethylene, 60 parts of maleic anhydride grafted low-density polyethylene, 20 parts of polyethylene/polyethylene terephthalate laminated powder and 0.6 part of silane coupling agent into the calcium carbonate inorganic filler of S11, continuously stirring for 3-5min, adding 0.6 part of stearic acid, adjusting the temperature to 90-100 ℃, and ultrasonically dispersing for 3-5h to obtain 300.5 parts of a mixed base material of the calcium carbonate inorganic filler and the polyethylene base material;

s13, sequentially adding 3 parts of styrene/acrylic acid/ethylhexyl acrylate/lauryl acrylate copolymer, 3 parts of polycaprolactone, 0.4 part of tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester, 0.2 part of tris (nonylphenol) phosphite ester, 0.2 part of ditridecyl alcohol thiodipropionate, 2 parts of colloidal molybdenum disulfide, 4 parts of diisostearyl alcohol dilinoleate and 0.5 part of polyoxyethylene ether-40 hydrogenated castor oil into a stirrer, and stirring and mixing uniformly at normal temperature to obtain 13.3 parts of mixed auxiliary agent;

s14, adjusting the temperature of the double-screw extruder to 120-130 ℃, mixing the mixed base material of S12 and 7.3 parts of mixed auxiliary agent, putting the mixture into the double-screw extruder, melting, extruding, cooling and granulating to obtain master batch;

s15, adjusting the temperature of the double-screw extruder to 120-130 ℃, mixing the master batch of S15 and 6 parts of mixing aid, and putting the mixture into the double-screw extruder for melt extrusion to obtain the resin material.

3. A method of blowing a breathable film according to claim 2, wherein: in the S11, the stirring temperature is 50-60 ℃, the rotation speed is 600-800r/min, and the time is 10-20 min.

4. A method of blowing a breathable film according to claim 2, wherein: in the step S13, the normal temperature stirring speed is 500-1000r/min, and the time is 3-5 min.

5. A method of blowing a breathable film according to claim 2, wherein: in the S15, the master batch is treated in advance by dissolving PVP/VA/vinyl propionate copolymer in water, heating to 190-200 ℃ under 14-15kPa to generate activated steam, then using nitrogen as a carrier to make the activated steam contact with the S14 master batch, adjusting the temperature to 700-800 ℃, keeping the temperature for 60-90min, then stopping adding the activated steam, and cooling to room temperature to obtain the treated master batch.

6. A method of blowing a breathable film according to claim 1, wherein: in the S2, the temperature of the melting section of the film blowing machine is 160-180 ℃, the temperature of the die head is 180-190 ℃, and the blow-up ratio is 2.0-4.0; the length-diameter ratio of the screw is (25-35): 1, the starting rotating speed of the screw is 15-25r/min, then the speed of the screw is gradually increased according to the rolling speed of the film, and the maximum rotating speed of the screw is 80 r/min.

7. A method of blowing a breathable film according to claim 1, wherein: in the step S3, the air speed of the double-air-ring film cooling device is 4-6m/S, the air temperature of the lower-layer air ring is 140-160 ℃, and the air temperature of the upper-layer air ring is 220-240 ℃, so that the distance between the tubular film cold frost line and the film blowing machine die head is 3 m.

8. A method of blowing a breathable film according to claim 1, wherein: in the S4, the stretching temperature is 90-105 ℃, and the setting temperature is 105-115 ℃.

9. A method of blowing a breathable film according to claim 1, wherein: in the S5, the bombardment intensity of the polar plate is 8.5-9.0 W.min/m.

Technical Field

The invention relates to the technical field of plastic films, in particular to a method for blowing a breathable film.

Background

Plastic films are mainly classified into two types, extrusion methods and calendering methods, as far as the molding method is concerned, and the extrusion methods are classified into extrusion blowing and extrusion casting. At present, the traditional polyethylene microporous breathable film in the domestic market is almost produced by adopting a tape casting method, and the traditional polyethylene microporous breathable film mainly has the following problems which are difficult to avoid and solve:

1) the reduction is the development direction of the current global plastic industry, the minimum square gram weight limit of the polyethylene microporous breathable film produced by the tape casting method in the industry is 15gsm, if patterns need to be accurately printed in a positioning way, the polyethylene microporous breathable film with the minimum square gram weight can not be used for the production of normal sanitary products because the polyethylene microporous breathable film is easy to be stretched and deformed;

2) the stretching and air permeability of the film are reduced along with the reduction of the square gram weight of the physical and mechanical properties of the traditional polyethylene microporous breathable film, and the traditional polyethylene microporous breathable film is easy to deform and stretch, so that the rejection rate of the breathable film in the production process is high;

3) because the tape casting method is usually used for molding after twice stretching, after the breathable film is subjected to twice necking, the scraps are removed too much, and the production consumption is too high.

Due to the strong demand of the market on functional films and the like and the development of a co-extrusion technology, compared with an extrusion casting and calendering method, the extrusion blowing method has the advantages of less investment on equipment, small occupied area and balanced longitudinal and transverse properties of the blown film, and the extrusion blown film is rapidly developed in recent years. The film blowing method is to melt and extrude the raw materials into thin tubes by an extruder, then to blow the thin tubes by compressed air while the thin tubes are hot, and to obtain the film products after cooling and shaping.

Although the blown breathable film solves the problem of poor stretching and air permeability caused by the original casting method, the sanitary product needs to have higher comfort level on the basis of ensuring the functionality of the sanitary product, namely, on the basis of no leakage after absorbing liquid. Wherein, the waterproof performance of the breathable film is high when the breathable film does not leak after absorbing liquid, and the breathable film is good in air permeability and moisture permeability when the comfort level is high. The air permeability and the moisture permeability of the air permeable membrane obtained by blowing at present can hardly meet the requirements if the anti-hydrostatic pressure performance is improved, and can hardly meet the requirements if the air permeability and the moisture permeability are improved, so that the problem of how to realize the common improvement of the anti-hydrostatic pressure performance, the air permeability and the moisture permeability of the air permeable membrane is urgently needed to be solved by a blowing method of the air permeable membrane.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a method for blowing a breathable film, which solves the problem of the prior art that how to realize the common improvement of the hydrostatic pressure resistance, the air permeability and the moisture permeability of the breathable film.

According to the embodiment of the invention, the method for blowing the breathable film comprises the following steps of mixing S1 raw materials, weighing the raw materials according to the parts by weight, uniformly mixing the calcium carbonate inorganic filler, the polyethylene base material and the mixing auxiliary agent, and performing melt extrusion to obtain a resin material; s2, performing film blowing molding, namely performing film blowing molding on the resin material prepared in the S1 on a single-screw film blowing machine to obtain a tubular film; s3, cooling by wind rings, namely, penetrating the tubular film of the S2 through a double-wind-ring film cooling device, and expanding and cooling the tubular film by a gas medium introduced into the space in the tubular film; s4 film shaping, namely sequentially clamping the S3 tubular film by a herringbone plate and folding and transiting the tubular film by a transition roller, then preheating the film to 70-90 ℃, and stretching and heat-shaping the film to obtain a semi-finished product of the breathable film; and S5, performing corona treatment, namely allowing the semi-finished product of the breathable film obtained in the step S4 to pass through a space between polar plates with high voltage, bombarding the outer side surface of the semi-finished product of the breathable film by high voltage, and then cutting edges and rolling to obtain the finished breathable film.

By adopting the technical scheme, the calcium carbonate inorganic filler, the polyethylene base material and the mixed auxiliary agent can be subjected to crosslinking modification in the melting process to form a molten resin material, so that a tubular film is formed by film blowing; in the air ring cooling process, the double-air-ring film cooling device enables the tubular film to be gradually cooled by arranging the upper air ring and the lower air ring, so that the condition that the tubular film is deformed due to the sudden temperature drop of one air ring is avoided, and the longitudinal and transverse performances of the tubular film are more balanced; then the tubular film is folded to form a sheet-shaped film, and the sheet-shaped film is preheated at 70-90 ℃ and then is stretched and shaped, so that the resin material in the sheet-shaped film can be uniformly spread, the unit gram weight of the sheet-shaped film can be reduced while the tensile property of the sheet-shaped film is ensured, and simultaneously, the calcium carbonate inorganic filler is beneficial to forming micropores which are uniformly distributed and have proper diameters on the surface of the sheet-shaped film, so that the hydrostatic pressure resistance, the air permeability and the moisture permeability of the breathable film are preliminarily balanced; finally, the polar plate utilizes high-frequency high voltage to carry out corona discharge on the surface of the semi-finished product of the treated breathable film to generate low-temperature plasma, so that the surface of the semi-finished product of the breathable film generates free radical reaction to further crosslink the polyethylene base material, wherein the generated plasma permeates into the micropores by electric shock and carries out surface modification on the semi-finished product of the breathable film, and the hydrostatic pressure resistance of the breathable film can be further improved while the surface performance of the breathable film is improved; in conclusion, the method provided by the invention initially balances the hydrostatic pressure resistance, air permeability and moisture permeability of the breathable film by improving the conditions of air ring cooling and film shaping, further improves the hydrostatic pressure resistance of the breathable film through corona treatment, and realizes the common improvement of the hydrostatic pressure resistance, the air permeability and the moisture permeability of the breathable film on the basis of high efficiency.

Further, in the step S1, the method comprises the following steps of S11, sequentially adding 120 parts of superfine heavy calcium carbonate calcium titanate, 50 parts of silica-based single-crystal single-layer graphene, 30 parts of nano titanium dioxide loaded silver ions and 0.5 part of polyoxyethylene ether-40 hydrogenated castor oil into a stirrer, and uniformly stirring to obtain 200.5 parts of calcium carbonate inorganic filler; s12, under the stirring state, sequentially adding 20 parts of metallocene linear low-density polyethylene, 60 parts of maleic anhydride grafted low-density polyethylene, 20 parts of polyethylene/polyethylene terephthalate laminated powder and 0.6 part of silane coupling agent into the calcium carbonate inorganic filler of S11, continuously stirring for 3-5min, adding 0.6 part of stearic acid, adjusting the temperature to 90-100 ℃, and ultrasonically dispersing for 3-5h to obtain 300.5 parts of a mixed base material of the calcium carbonate inorganic filler and the polyethylene base material; s13, sequentially adding 3 parts of styrene/acrylic acid/ethylhexyl acrylate/lauryl acrylate copolymer, 3 parts of polycaprolactone, 0.4 part of tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester, 0.2 part of tris (nonylphenol) phosphite ester, 0.2 part of ditridecyl alcohol thiodipropionate, 2 parts of colloidal molybdenum disulfide, 4 parts of diisostearyl alcohol dilinoleate and 0.5 part of polyoxyethylene ether-40 hydrogenated castor oil into a stirrer, and stirring and mixing uniformly at normal temperature to obtain 13.3 parts of mixed auxiliary agent; s14, adjusting the temperature of the double-screw extruder to 120-130 ℃, mixing the mixed base material of S12 and 7.3 parts of mixed auxiliary agent, putting the mixture into the double-screw extruder, melting, extruding, cooling and granulating to obtain master batch; s15, adjusting the temperature of the double-screw extruder to 120-130 ℃, mixing the master batch of S15 and 6 parts of mixing aid, and putting the mixture into the double-screw extruder for melt extrusion to obtain the resin material.

Firstly, in calcium carbonate inorganic filler, polyoxyethylene ether-40 hydrogenated castor oil can promote ultrafine heavy calcium carbonate and silicon dioxide to be used as basic frameworks to be dispersed in a resin material, and meanwhile, a silicon dioxide thin layer is deposited on the surface of graphene, so that the pi stacking effect among graphene sheet layers is hindered, and the uniform dispersion of the graphene is realized; on the basis, the graphene, the nano titanium dioxide and the nano silver are uniformly dispersed in the resin material as the particle filler, so that the use amount of the superfine heavy calcium carbonate is reduced, the problem of compatibility between the overlarge amount of the superfine heavy calcium carbonate and a polyethylene base material is directly avoided, the adsorption performance, the air permeability and the moisture permeability of the resin material are improved, and the resin material has good antibacterial property and the effects of removing formaldehyde and resisting ultraviolet aging; secondly, after the maleic anhydride grafted low-density polyethylene is blended with the polyethylene/polyethylene terephthalate laminated powder, the polarity and corona resistance of the surface of the polyethylene/polyethylene terephthalate laminated powder and the grafting rate between the polyethylene/polyethylene terephthalate laminated powder and a silane coupling agent can be improved, and a low-density polyethylene system formed on the basis is mixed with the metallocene linear low-density polyethylene in the proportion, so that the tensile property of a resin material can be effectively improved under the conditions of controlling the cost and improving the compatibility, and calcium carbonate inorganic filler is promoted to form micropores which are uniformly distributed and have proper diameters on the surface of a flaky film; then, under the ultrasonic condition, the mechanical property of the metallocene low-density polyethylene can be improved, silane grafting of a silane coupling agent on polyethylene/polyethylene terephthalate laminated powder is facilitated, and then stearic acid is utilized to modify a polyethylene base material, so that the cross-linking reaction of each component of the resin material is facilitated to be controlled, the high dispersion of the resin material is ensured, meanwhile, the melt defect of the resin material can be effectively reduced in the processing process, the phenomenon that polyoxyethylene ether-40 hydrogenated castor oil is carbonized at high temperature and accumulated at the orifice of a die head in the extrusion process is avoided, and the phenomena of unstable extrusion, uneven product and the like are avoided; finally, the mixing aid mainly plays a role in adjusting the viscosity of the resin material and increasing the processing stability and long-acting stability of the resin material, so that the resin material has better flexibility and cold resistance, the tensile property of the breathable film prepared from the resin material is further improved, the mixing aid is divided into two parts and is respectively put into the two parts in batches before and after granulation, the plasticity of the resin material can be further improved, and the prepared breathable film has better hydrostatic pressure resistance.

Preferably, in S11, the stirring temperature is 50-60 ℃, the rotation speed is 600-800r/min, and the time is 10-20 min. Under the stirring condition, the superfine heavy calcium carbonate calcium titanate, the silicon dioxide substrate single-crystal single-layer graphene, the nano titanium dioxide loaded silver ions and the polyoxyethylene ether-40 hydrogenated castor oil can be fully and uniformly mixed.

Preferably, in S13, the normal temperature stirring rotation speed is 500-. Under the stirring condition, the calcium carbonate inorganic filler and the polyethylene base material can be fully and uniformly mixed.

Preferably, in the S15, the master batch is treated in advance by dissolving PVP/VA/vinyl propionate copolymer in water, heating to 190-. The surface of the master batch can be activated by the activation steam generated by the PVP/VA/vinyl propionate copolymer, so that the surface of the master batch has excellent film forming, dispersing and adsorbing properties, and the master batch is convenient to store and transfer and is convenient to uniformly disperse and compatibilize after the master batch is melted again.

Further, in the S2, the temperature of the melting section of the film blowing machine is 160-180 ℃, the temperature of the die head is 180-190 ℃, and the blow-up ratio is 2.0-4.0; the length-diameter ratio of the screw is (25-35): 1, the starting rotating speed of the screw is 15-25r/min, then the speed of the screw is gradually increased according to the rolling speed of the film, and the maximum rotating speed of the screw is 80 r/min. The tubular film obtained under the condition has uniform thickness and is convenient for subsequent stretching operation.

Further, in the step S3, the air speed of the double-air-ring film cooling device is 4-6m/S, the air temperature of the lower-layer air ring is 140-160 ℃, and the air temperature of the upper-layer air ring is 220-240 ℃, so that the tubular film cold frost line is 3m away from the film blowing machine die head. The air outlet of the air ring is usually positioned on the inner side surface of the air ring, and the tubular film can prevent molecular chains of polyethylene from contacting an oriented structure under the air speed and the air temperature, so that the tubular film is prevented from shrinking and deforming; specifically, when the tubular film passes through the lower layer wind ring, the tubular film is cooled to 140-160 ℃ from more than 250 ℃, the cooling temperature difference is proper, the tubular film can be cooled and plasticized at the cold frost line, then the tubular film passes through the upper layer wind ring, and the tubular film is preheated to more than 200 ℃ by the upper layer wind ring, so that the subsequent tubular film is folded into a sheet-shaped film, and the production efficiency of the breathable film is improved.

Further, in the S4, the stretching temperature is 90-105 ℃, and the setting temperature is 105-115 ℃. At the temperature, the calcium carbonate inorganic filler is favorable for forming micropores with uniform distribution and proper diameter on the surface of the flaky film so as to initially balance the hydrostatic pressure resistance, the air permeability and the moisture permeability of the breathable film.

Furthermore, in the S5, the bombardment intensity of the polar plate is 8.5-9.0 W.min/m. Under the bombardment intensity, the air quantity between the polar plates can be in a relatively stable state, and more oxygen molecules are activated, so that oxygen-containing functional groups can be electret to the surface of the breathable film, and the hydrostatic pressure resistance, the breathability and the moisture permeability of the breathable film are improved together.

Compared with the prior art, the invention has the following beneficial effects: through the condition of improving wind ring cooling and film design to the hydrostatic pressure performance, gas permeability and the moisture permeability of preliminary balance ventilated membrane, and further improve the hydrostatic pressure performance of ventilated membrane through corona treatment, on taking into account the efficient basis, realized the improvement jointly of hydrostatic pressure performance, gas permeability and the moisture permeability of ventilated membrane.

Detailed Description

The technical solution of the present invention is further illustrated by the following examples.

Examples

Example 1: the invention discloses a method for blowing a breathable film, which comprises the following steps,

s1, mixing raw materials, weighing the raw materials according to parts by weight, uniformly mixing the calcium carbonate inorganic filler, the polyethylene base material and the auxiliary agent, and performing melt extrusion to obtain a resin material;

s2, performing film blowing molding, namely performing film blowing molding on the resin material prepared in the S1 on a single-screw film blowing machine to obtain a tubular film; wherein the melting section temperature of the film blowing machine is 160 ℃, the die head temperature is 180 ℃, the blowing ratio is 2.0, the length-diameter ratio of the screw is 25: 1, starting the screw at a rotating speed of 15r/min, and then gradually increasing the screw speed according to the film winding speed, wherein the maximum rotating speed of the screw is 80 r/min;

s3 wind ring cooling, namely, the tubular film of S2 is arranged through a double wind ring film cooling device, and the tubular film is expanded and cooled by a gas medium introduced into the space in the tubular film; wherein the air speed of the double-air-ring film cooling device is 4m/s, the air temperature of the lower-layer air ring is 140 ℃, and the air temperature of the upper-layer air ring is 220 ℃, so that the distance between the cold frost line of the tubular film and the die head of the film blowing machine is 3 m;

shaping the S4 film, namely sequentially clamping the S3 tubular film by a herringbone plate and folding and transiting the tubular film by a transition roller, then preheating the film to 90 ℃, and stretching and heat-shaping the film to obtain a semi-finished product of the breathable film; wherein the stretching temperature is 105 ℃, and the heat setting temperature is 115 ℃;

s5, performing corona treatment, namely allowing the semi-finished product of the breathable film obtained in the S4 to pass through a space between polar plates with high voltage, bombarding the outer side surface of the semi-finished product of the film by high voltage, and then cutting edges and rolling to obtain the finished breathable film; wherein the bombardment intensity of the polar plate is 8.5 W.min/m.

In addition, the specific steps of S1 are,

s11, sequentially adding 120 parts of superfine heavy calcium carbonate calcium titanate, 50 parts of silicon dioxide substrate single-crystal single-layer graphene, 30 parts of nano titanium dioxide loaded silver ions and 0.5 part of polyoxyethylene ether-40 hydrogenated castor oil into a stirrer, adjusting the temperature to 50 ℃, stirring at a constant temperature of 600r/min for 10min to obtain 200.5 parts of calcium carbonate inorganic filler;

s12, under the stirring state, sequentially adding 20 parts of metallocene linear low-density polyethylene, 60 parts of maleic anhydride grafted low-density polyethylene, 20 parts of polyethylene/polyethylene terephthalate laminated powder and 0.6 part of silane coupling agent into the calcium carbonate inorganic filler of S11, continuously stirring for 3min, adding 0.6 part of stearic acid, adjusting the temperature to 90 ℃, and ultrasonically dispersing for 3h to obtain 300.5 parts of a mixed base material of the calcium carbonate inorganic filler and the polyethylene base material;

s13 adding 3 parts of styrene/acrylic acid/ethylhexyl acrylate/lauryl acrylate copolymer, 3 parts of polycaprolactone, 0.4 part of tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester, 0.2 part of tris (nonylphenol) phosphite ester, 0.2 part of ditridecyl alcohol thiodipropionate, 2 parts of colloidal molybdenum disulfide, 4 parts of diisostearyl alcohol dilinoleate and 0.5 part of polyoxyethylene ether-40 hydrogenated castor oil into a stirrer in sequence, stirring at the normal temperature for 3min to obtain 13.3 parts of mixed auxiliary agent;

s14, adjusting the temperature of the double-screw extruder to 120 ℃, mixing the mixed base material of the calcium carbonate inorganic filler and the polyethylene base material of S12 with 7.3 parts of mixed auxiliary agent, putting the mixture into the double-screw extruder, and performing melt extrusion, cooling and grain cutting to obtain master batches;

s15 dissolving PVP/VA/vinyl propionate copolymer in water, heating to 190 ℃ under 14kPa to generate activated steam, then using nitrogen as a carrier to enable the activated steam to be in contact with the S14 master batch, adjusting the temperature to 700 ℃, preserving the temperature for 60min, stopping adding the activated steam, and cooling to room temperature to obtain a semi-finished resin product;

s16, adjusting the temperature of the double-screw extruder to 120 ℃, mixing the semi-finished resin product of S15 and 6 parts of mixing aid, and putting the mixture into the double-screw extruder for melt extrusion to obtain the resin material.

Example 2: the invention discloses a method for blowing a breathable film, which comprises the following steps,

s1, mixing raw materials, weighing the raw materials according to parts by weight, uniformly mixing the calcium carbonate inorganic filler, the polyethylene base material and the auxiliary agent, and performing melt extrusion to obtain a resin material;

s2, performing film blowing molding, namely performing film blowing molding on the resin material prepared in the S1 on a single-screw film blowing machine to obtain a tubular film; wherein the temperature of the melting section of the film blowing machine is 165 ℃, the temperature of the die head is 185 ℃, the blowing ratio is 2.0, and the length-diameter ratio of the screw is 35: 1, the starting rotating speed of a screw is 20r/min, then the speed of the screw is gradually increased according to the rolling speed of a film, and the maximum rotating speed of the screw is 80 r/min;

s3 wind ring cooling, namely, the tubular film of S2 is arranged through a double wind ring film cooling device, and the tubular film is expanded and cooled by a gas medium introduced into the space in the tubular film; wherein the air speed of the double-air-ring film cooling device is 5m/s, the air temperature of the lower-layer air ring is 150 ℃, and the air temperature of the upper-layer air ring is 230 ℃, so that the distance between the cold frost line of the tubular film and the die head of the film blowing machine is 3 m;

shaping the S4 film, namely sequentially clamping the S3 tubular film by a herringbone plate and folding and transiting the tubular film by a transition roller, then preheating the film to 85 ℃, and stretching and heat-shaping the film to obtain a semi-finished product of the breathable film; wherein the stretching temperature is 100 ℃, and the heat setting temperature is 110 ℃;

s5, performing corona treatment, namely allowing the semi-finished product of the breathable film obtained in the S4 to pass through a space between polar plates with high voltage, bombarding the outer side surface of the semi-finished product of the film by high voltage, and then cutting edges and rolling to obtain the finished breathable film; wherein the bombardment intensity of the polar plate is 8.6 W.min/m.

In addition, the specific steps of S1 are,

s11, sequentially adding 120 parts of superfine heavy calcium carbonate calcium titanate, 50 parts of silicon dioxide substrate single-crystal single-layer graphene, 30 parts of nano titanium dioxide loaded silver ions and 0.5 part of polyoxyethylene ether-40 hydrogenated castor oil into a stirrer, adjusting the temperature to 55 ℃, stirring at a constant temperature of 650r/min for 15min to obtain 200.5 parts of calcium carbonate inorganic filler;

s12, under the stirring state, sequentially adding 20 parts of metallocene linear low-density polyethylene, 60 parts of maleic anhydride grafted low-density polyethylene, 20 parts of polyethylene/polyethylene terephthalate laminated powder and 0.6 part of silane coupling agent into the calcium carbonate inorganic filler of S11, continuously stirring for 4min, adding 0.6 part of stearic acid, adjusting the temperature to 95 ℃, and ultrasonically dispersing for 5h to obtain 300.5 parts of a mixed base material of the calcium carbonate inorganic filler and the polyethylene base material;

s13 adding 3 parts of styrene/acrylic acid/ethylhexyl acrylate/lauryl acrylate copolymer, 3 parts of polycaprolactone, 0.4 part of tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester, 0.2 part of tris (nonylphenol) phosphite ester, 0.2 part of ditridecyl alcohol thiodipropionate, 2 parts of colloidal molybdenum disulfide, 4 parts of diisostearyl alcohol dilinoleate and 0.5 part of polyoxyethylene ether-40 hydrogenated castor oil into a stirrer in sequence, stirring at 600r/min and stirring at normal temperature for 4min to obtain 13.3 parts of mixed auxiliary agent;

s14, adjusting the temperature of the double-screw extruder to 125 ℃, mixing the mixed base material of the calcium carbonate inorganic filler and the polyethylene base material of S12 with 7.3 parts of mixed auxiliary agent, putting the mixture into the double-screw extruder, and performing melt extrusion, cooling and grain cutting to obtain master batches;

s15 dissolving PVP/VA/vinyl propionate copolymer in water, heating to 200 ℃ under 15kPa to generate activated steam, then using nitrogen as a carrier to enable the activated steam to be in contact with the S14 master batch, adjusting the temperature to 750 ℃, preserving the temperature for 70min, stopping adding the activated steam, and cooling to room temperature to obtain a semi-finished resin product;

s16, adjusting the temperature of the double-screw extruder to 125 ℃, mixing the semi-finished resin product of S15 and 6 parts of mixing aid, and putting the mixture into the double-screw extruder for melt extrusion to obtain the resin material.

Example 3: the invention discloses a method for blowing a breathable film, which comprises the following steps,

s1, mixing raw materials, weighing the raw materials according to parts by weight, uniformly mixing the calcium carbonate inorganic filler, the polyethylene base material and the auxiliary agent, and performing melt extrusion to obtain a resin material;

s2, performing film blowing molding, namely performing film blowing molding on the resin material prepared in the S1 on a single-screw film blowing machine to obtain a tubular film; wherein the temperature of the melting section of the film blowing machine is 170 ℃, the temperature of the die head is 190 ℃, the blow-up ratio is 3.0, and the length-diameter ratio of the screw is 30: 1, the starting rotating speed of a screw is 25r/min, then the speed of the screw is gradually increased according to the rolling speed of a film, and the maximum rotating speed of the screw is 80 r/min;

s3 wind ring cooling, namely, the tubular film of S2 is arranged through a double wind ring film cooling device, and the tubular film is expanded and cooled by a gas medium introduced into the space in the tubular film; wherein the air speed of the double-air-ring film cooling device is 5m/s, the air temperature of the lower-layer air ring is 160 ℃, and the air temperature of the upper-layer air ring is 240 ℃, so that the distance between the cold frost line of the tubular film and the die head of the film blowing machine is 3 m;

shaping the S4 film, namely sequentially clamping the S3 tubular film by a herringbone plate and folding and transiting the tubular film by a transition roller, then preheating the film to 80 ℃, and stretching and heat-shaping the film to obtain a semi-finished product of the breathable film; wherein the stretching temperature is 95 ℃, and the heat setting temperature is 105 ℃;

s5, performing corona treatment, namely allowing the semi-finished product of the breathable film obtained in the S4 to pass through a space between polar plates with high voltage, bombarding the outer side surface of the semi-finished product of the film by high voltage, and then cutting edges and rolling to obtain the finished breathable film; wherein the bombardment intensity of the polar plate is 8.7 W.min/m.

In addition, the specific steps of S1 are,

s11, sequentially adding 120 parts of superfine heavy calcium carbonate calcium titanate, 50 parts of silicon dioxide substrate single-crystal single-layer graphene, 30 parts of nano titanium dioxide loaded silver ions and 0.5 part of polyoxyethylene ether-40 hydrogenated castor oil into a stirrer, adjusting the temperature to 60 ℃, stirring at a constant temperature of 700r/min for 20min to obtain 200.5 parts of calcium carbonate inorganic filler;

s12, under the stirring state, sequentially adding 20 parts of metallocene linear low-density polyethylene, 60 parts of maleic anhydride grafted low-density polyethylene, 20 parts of polyethylene/polyethylene terephthalate laminated powder and 0.6 part of silane coupling agent into the calcium carbonate inorganic filler of S11, continuously stirring for 5min, adding 0.6 part of stearic acid, adjusting the temperature to 100 ℃, and ultrasonically dispersing for 4h to obtain 300.5 parts of a mixed base material of the calcium carbonate inorganic filler and the polyethylene base material;

s13 adding 3 parts of styrene/acrylic acid/ethylhexyl acrylate/lauryl acrylate copolymer, 3 parts of polycaprolactone, 0.4 part of tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester, 0.2 part of tris (nonylphenol) phosphite ester, 0.2 part of ditridecyl alcohol thiodipropionate, 2 parts of colloidal molybdenum disulfide, 4 parts of diisostearyl alcohol dilinoleate and 0.5 part of polyoxyethylene ether-40 hydrogenated castor oil into a stirrer in sequence, stirring at the normal temperature for 5min, and obtaining 13.3 parts of mixed auxiliary agent;

s14, adjusting the temperature of the double-screw extruder to 130 ℃, mixing the mixed base material of the calcium carbonate inorganic filler and the polyethylene base material of S12 with 7.3 parts of mixed auxiliary agent, putting the mixture into the double-screw extruder, and performing melt extrusion, cooling and grain cutting to obtain master batches;

s15 dissolving PVP/VA/vinyl propionate copolymer in water, heating to 195 ℃ under 14kPa to generate activated steam, then using nitrogen as a carrier to enable the activated steam to be in contact with the S14 master batch, adjusting the temperature to 800 ℃, keeping the temperature for 75min, stopping adding the activated steam, and cooling to room temperature to obtain a semi-finished resin product;

s16, adjusting the temperature of the double-screw extruder to 130 ℃, mixing the semi-finished resin product of S15 and 6 parts of mixing aid, and putting the mixture into the double-screw extruder for melt extrusion to obtain the resin material.

Example 4: the invention discloses a method for blowing a breathable film, which comprises the following steps,

s1, mixing raw materials, weighing the raw materials according to parts by weight, uniformly mixing the calcium carbonate inorganic filler, the polyethylene base material and the auxiliary agent, and performing melt extrusion to obtain a resin material;

s2, performing film blowing molding, namely performing film blowing molding on the resin material prepared in the S1 on a single-screw film blowing machine to obtain a tubular film; wherein the melting section temperature of the film blowing machine is 175 ℃, the die head temperature is 185 ℃, the blowing ratio is 3.0, the length-diameter ratio of the screw is 25: 1, starting the screw at a rotating speed of 18r/min, and then gradually increasing the screw speed according to the film winding speed, wherein the maximum rotating speed of the screw is 80 r/min;

s3 wind ring cooling, namely, the tubular film of S2 is arranged through a double wind ring film cooling device, and the tubular film is expanded and cooled by a gas medium introduced into the space in the tubular film; wherein the air speed of the double-air-ring film cooling device is 6m/s, the air temperature of the lower-layer air ring is 150 ℃, and the air temperature of the upper-layer air ring is 230 ℃, so that the distance between the cold frost line of the tubular film and the die head of the film blowing machine is 3 m;

shaping the S4 film, namely sequentially clamping the S3 tubular film by a herringbone plate and folding and transiting the tubular film by a transition roller, then preheating the film to 75 ℃, and stretching and heat-shaping the film to obtain a semi-finished product of the breathable film; wherein the stretching temperature is 90 ℃, and the heat setting temperature is 110 ℃;

s5, performing corona treatment, namely allowing the semi-finished product of the breathable film obtained in the S4 to pass through a space between polar plates with high voltage, bombarding the outer side surface of the semi-finished product of the film by high voltage, and then cutting edges and rolling to obtain the finished breathable film; wherein the bombardment intensity of the polar plate is 8.8 W.min/m.

In addition, the specific steps of S1 are,

s11, sequentially adding 120 parts of superfine heavy calcium carbonate calcium titanate, 50 parts of silicon dioxide substrate single-crystal single-layer graphene, 30 parts of nano titanium dioxide loaded silver ions and 0.5 part of polyoxyethylene ether-40 hydrogenated castor oil into a stirrer, adjusting the temperature to 60 ℃, 750r/min, and stirring at constant temperature for 15min to obtain 200.5 parts of calcium carbonate inorganic filler;

s12, under the stirring state, sequentially adding 20 parts of metallocene linear low-density polyethylene, 60 parts of maleic anhydride grafted low-density polyethylene, 20 parts of polyethylene/polyethylene terephthalate laminated powder and 0.6 part of silane coupling agent into the calcium carbonate inorganic filler of S11, continuously stirring for 4min, adding 0.6 part of stearic acid, adjusting the temperature to 90 ℃, and ultrasonically dispersing for 3h to obtain 300.5 parts of a mixed base material of the calcium carbonate inorganic filler and the polyethylene base material;

s13 adding 3 parts of styrene/acrylic acid/ethylhexyl acrylate/lauryl acrylate copolymer, 3 parts of polycaprolactone, 0.4 part of tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester, 0.2 part of tris (nonylphenol) phosphite ester, 0.2 part of ditridecyl alcohol thiodipropionate, 2 parts of colloidal molybdenum disulfide, 4 parts of diisostearyl alcohol dilinoleate and 0.5 part of polyoxyethylene ether-40 hydrogenated castor oil into a stirrer in sequence, stirring at the normal temperature for 3min to obtain 13.3 parts of mixed auxiliary agent;

s14, adjusting the temperature of the double-screw extruder to 120 ℃, mixing the mixed base material of the calcium carbonate inorganic filler and the polyethylene base material of S12 with 7.3 parts of mixed auxiliary agent, putting the mixture into the double-screw extruder, and performing melt extrusion, cooling and grain cutting to obtain master batches;

s15 dissolving PVP/VA/vinyl propionate copolymer in water, heating to 195 ℃ under 15kPa to generate activated steam, then using nitrogen as a carrier to enable the activated steam to be in contact with the S14 master batch, adjusting the temperature to 700 ℃, preserving the temperature for 80min, stopping adding the activated steam, and cooling to room temperature to obtain a semi-finished resin product;

s16, adjusting the temperature of the double-screw extruder to 125 ℃, mixing the semi-finished resin product of S15 and 6 parts of mixing aid, and putting the mixture into the double-screw extruder for melt extrusion to obtain the resin material.

Example 5: the invention discloses a method for blowing a breathable film, which comprises the following steps,

s1, mixing raw materials, weighing the raw materials according to parts by weight, uniformly mixing the calcium carbonate inorganic filler, the polyethylene base material and the auxiliary agent, and performing melt extrusion to obtain a resin material;

s2, performing film blowing molding, namely performing film blowing molding on the resin material prepared in the S1 on a single-screw film blowing machine to obtain a tubular film; wherein the melting section temperature of the film blowing machine is 180 ℃, the die head temperature is 185 ℃, the blowing ratio is 4.0, the length-diameter ratio of the screw is 35: 1, starting the screw at a rotating speed of 22r/min, and then gradually increasing the screw speed according to the film winding speed, wherein the maximum rotating speed of the screw is 80 r/min;

s3 wind ring cooling, namely, the tubular film of S2 is arranged through a double wind ring film cooling device, and the tubular film is expanded and cooled by a gas medium introduced into the space in the tubular film; wherein the air speed of the double-air-ring film cooling device is 6m/s, the air temperature of the lower-layer air ring is 160 ℃, and the air temperature of the upper-layer air ring is 240 ℃, so that the distance between the cold frost line of the tubular film and the die head of the film blowing machine is 3 m;

shaping the S4 film, namely sequentially clamping the S3 tubular film by a herringbone plate and folding and transiting the tubular film by a transition roller, then preheating the film to 70 ℃, and stretching and heat-shaping the film to obtain a semi-finished product of the breathable film; wherein the stretching temperature is 100 ℃, and the heat setting temperature is 110 ℃;

s5, performing corona treatment, namely allowing the semi-finished product of the breathable film obtained in the S4 to pass through a space between polar plates with high voltage, bombarding the outer side surface of the semi-finished product of the film by high voltage, and then cutting edges and rolling to obtain the finished breathable film; wherein the bombardment intensity of the polar plate is 9.0 W.min/m.

In addition, the specific steps of S1 are,

s11, sequentially adding 120 parts of superfine heavy calcium carbonate calcium titanate, 50 parts of silicon dioxide substrate single-crystal single-layer graphene, 30 parts of nano titanium dioxide loaded silver ions and 0.5 part of polyoxyethylene ether-40 hydrogenated castor oil into a stirrer, adjusting the temperature to 50 ℃, stirring at the constant temperature of 800r/min for 20min to obtain 200.5 parts of calcium carbonate inorganic filler;

s12, under the stirring state, sequentially adding 20 parts of metallocene linear low-density polyethylene, 60 parts of maleic anhydride grafted low-density polyethylene, 20 parts of polyethylene/polyethylene terephthalate laminated powder and 0.6 part of silane coupling agent into the calcium carbonate inorganic filler of S11, continuously stirring for 3min, adding 0.6 part of stearic acid, adjusting the temperature to 100 ℃, and ultrasonically dispersing for 4h to obtain 300.5 parts of a mixed base material of the calcium carbonate inorganic filler and the polyethylene base material;

s13 adding 3 parts of styrene/acrylic acid/ethylhexyl acrylate/lauryl acrylate copolymer, 3 parts of polycaprolactone, 0.4 part of tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester, 0.2 part of tris (nonylphenol) phosphite ester, 0.2 part of ditridecyl alcohol thiodipropionate, 2 parts of colloidal molybdenum disulfide, 4 parts of diisostearyl alcohol dilinoleate and 0.5 part of polyoxyethylene ether-40 hydrogenated castor oil into a stirrer in sequence, stirring at the normal temperature for 5min at 1000r/min to obtain 13.3 parts of mixed auxiliary agent;

s14, adjusting the temperature of the double-screw extruder to 130 ℃, mixing the mixed base material of the calcium carbonate inorganic filler and the polyethylene base material of S12 with 7.3 parts of mixed auxiliary agent, putting the mixture into the double-screw extruder, and performing melt extrusion, cooling and grain cutting to obtain master batches;

s15 dissolving PVP/VA/vinyl propionate copolymer in water, heating to 200 ℃ under 14kPa to generate activated steam, then using nitrogen as a carrier to enable the activated steam to be in contact with the S14 master batch, adjusting the temperature to 800 ℃, keeping the temperature for 90min, stopping adding the activated steam, and cooling to room temperature to obtain a semi-finished resin product;

s16, adjusting the temperature of the double-screw extruder to 125 ℃, mixing the semi-finished resin product of S15 and 6 parts of mixing aid, and putting the mixture into the double-screw extruder for melt extrusion to obtain the resin material.

Performance test

The films prepared according to the above examples were tested for grammage, thickness, tensile properties, water vapor transmission rate and hydrostatic pressure, and the results are shown in table 1. Wherein, the detection method of the gram weight is shown in GB/T31729-2015, the detection method of the thickness is shown in GB/T6672-2001, the detection method of the tensile property is shown in GB/T1040.1-2018, the detection method of the water vapor transmission rate is shown in GB/T30412-2013, and the detection method of the antistatic pressure is shown in ISO 811-1981.

TABLE 1

Detecting items	Example 1	Example 2	Example 3	Example 4	Example 5
						Thickness (μm)	2.3	3.2	2.2	3.1	2.1
Gram weight (g/cm)3)	12.3	11.5	11.8	11.7	12.0
						Breadth (mm)	3200.0	3200.0	3200.0	3200.0	3200.0
Draw ratio (%)	4000.0	4000.0	4000.0	4000.0	4000.0
						Production speed (m/min)	195.0	195.0	215.0	215.0	230.0
Yield (kg/h)	438.0	442.0	503.6	467.6	483.9
						Power consumption (kw/T)	504.0	501.0	447.0	458.0	475.0
10% fixed extension (N)	7.5	5.1	7.3	7.2	6.9
							2.3	1.7	2.1	2.2	2.0
Longitudinal tension (N)	15.0	11.9	15.1	16.9	15.9
						Longitudinal elongation (%)	49.2	56.9	50.1	48.3	43.0
Transverse pulling force (N)	1.3	1.3	1.9	1.8	2.0
						Transverse elongation (%)	121.3	140.0	107.0	106.6	128.4
Water vapor transmission rate (g/(cm)3·24h))	3745	3260.0	2763.0	2621.0	3399.0
						Hydrostatic pressure (mbar)	9325	8382.0	8993.0	8712.0	9841.0

As can be seen from Table 1, the breathable film prepared by the method disclosed by the invention has the advantages of small thickness, low gram weight and good tensile property, and on the basis, the water vapor transmission rate and the hydrostatic pressure resistance of the breathable film are relatively balanced, so that the hydrostatic pressure resistance, the breathability and the moisture permeability of the breathable film are improved together.

Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.