Waterproof vapor-permeable membrane as well as preparation method and application thereof

Abstract

The invention provides a waterproof vapor-permeable membrane as well as a preparation method and application thereof, and relates to the technical field of high polymer materials.The preparation method comprises the following steps: uniformly mixing high polymer resin master batch, a lubricant and an auxiliary agent to obtain a mixture; the auxiliary agent comprises at least one of an antioxidant and a catalyst; the use amount of the lubricant is 0.5-1.5 wt% of that of the high-molecular resin master batch; the use amount of the auxiliary agent is 0.1-0.5 wt% of that of the high-molecular resin master batch; and carrying out melt extrusion and calendaring molding on the mixture to obtain the waterproof vapor-permeable film. The waterproof vapor-permeable film provided by the invention has excellent mechanical properties and moisture permeability.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly relates to a waterproof and breathable film, a preparation method thereof, and an application thereof. Background Art

[0002] In the traditional construction field, asphalt waterproof coiled materials and coating waterproof materials are laid on the roof base layer to achieve the purpose of waterproofing. The asphalt waterproof coiled materials and coating waterproof materials have the characteristics of self-adhesion and airtightness, resulting in the residual moisture in the concrete structure being sealed in the structure, and the water vapor in the concrete structure cannot be dissipated, leading to the growth of mold on the roof and walls, and the indoor air quality and human health are seriously threatened.

[0003] In order to improve the above problems, an airtight film is laid on the roof base layer as an air barrier layer in a non-bonded manner, so that the water vapor in the cast-in-place concrete roof can be discharged to a certain extent, and the speed of water vapor in the concrete roof discharging to the insulation layer is slowed down; a breathable waterproof film is used as a building cladding system, which not only prevents the liquid water and vapor water infiltrating from the outside of the building, but also enables the water vapor in the insulation layer to be quickly discharged. The combined use of the air barrier layer and the waterproof and breathable film strengthens the airtightness and water tightness of the building, solves the problems of moisture proofing and mold, and effectively protects the thermal performance of the enclosure structure, thus truly achieving the purpose of energy conservation.

[0004] However, most of the existing waterproof film materials have mutual restrictions on waterproof and breathable properties, that is, they have good waterproof properties but poor breathability, or good breathability but poor waterproof properties, and cannot meet the multiple functional requirements in special environments such as building exterior walls, electronic device casings, and medical devices. In addition, the existing polymer waterproof and breathable film technology still faces the challenges of how to balance mechanical properties, waterproof properties, breathable properties, and airtightness, especially the stability and durability problems during long-term use. Summary of the Invention

[0005] In view of one or more technical problems in the prior art, an embodiment of the present invention provides a waterproof and breathable film, a preparation method thereof, and an application thereof. The waterproof and breathable film is a waterproof and breathable film with excellent mechanical properties and moisture permeability, and can meet multiple functional requirements.

[0006] The present invention provides a preparation method of a waterproof and breathable film in the first aspect. The preparation method includes:

[0007] Mix a polymer resin masterbatch, a lubricant, and an auxiliary agent to obtain a mixture; the auxiliary agent includes at least one of an antioxidant and a catalyst; the dosage of the lubricant is 0.5-1.5 wt% of the polymer resin masterbatch; the dosage of the auxiliary agent is 0.1-0.5 wt% of the polymer resin masterbatch;

[0008] The mixture is melt-extruded and calendered to obtain a waterproof and breathable film.

[0009] Preferably, the dosage of the lubricant is 0.5-1 wt% of the polymer resin masterbatch.

[0010] Preferably, the dosage of the auxiliary agent is 0.1-0.2 wt% of the polymer resin masterbatch.

[0011] Preferably, the polymer resin masterbatch is selected from one or more of polyester, polyurethane, and polytetrafluoroethylene; and / or

[0012] The lubricant is one or more of methyl silicone oil, ethyl silicone oil, stearic acid amide, oleic acid amide, microcrystalline wax, and polyethylene wax.

[0013] Preferably, the antioxidant is one or more of mercaptoethanol, mercaptopropanol, 2,6-di-tert-butyl-p-cresol, tert-butyl-4-hydroxyanisole, and tert-butyl hydroquinone; and / or

[0014] The catalyst is one or more of peroxide catalysts and basic catalysts.

[0015] Preferably, the peroxide catalyst is one or more of benzoyl peroxide and dicumyl peroxide; and / or

[0016] The basic catalyst is one or more of dimethylaniline, triethanolamine, sodium hydroxide, and potassium hydroxide.

[0017] Preferably, the melt extrusion is achieved by a twin-screw extruder, and the rotational speed of the twin-screw during the melt extrusion process is 60-80 r / min, and the feeding speed is 5-15 g / min;

[0018] The twin-screw extruder includes a first temperature zone, a second temperature zone, and a third temperature zone with sequentially increasing temperatures along the direction of screw rotation. The temperature of the first temperature zone is 190-200 °C, the temperature of the second temperature zone is 200-210 °C, and the temperature of the third temperature zone is 205-220 °C.

[0019] Preferably, the calendering is achieved by a three-roll calender and a traction roll;

[0020] The temperature of the upper roll of the three-roll calender is 180-200 °C, and the rotational speed is 20-22 rpm;

[0021] The temperature of the middle roll of the three-roll calender is 175-200 °C, and the rotational speed is 21.5-23.5 rpm;

[0022] The temperature of the lower roll of the three-roll calender is 170-195 °C, and the rotational speed is 23-24 rpm;

[0023] The traction roller of the three-roll calender rotates at a speed of 23 - 29 rpm.

[0024] In a second aspect, the present invention provides a waterproof and breathable film, which is prepared by the preparation method described in the first aspect.

[0025] In a third aspect, the present invention provides an application of the waterproof and breathable film described in the second aspect, which is applied to the fields of architecture, electronics, medical treatment, and textiles.

[0026] Compared with the prior art, the present invention has at least the following beneficial effects:

[0027] By controlling the dosages of the polymer resin masterbatch, lubricant, and additives, the present invention obtains a mixture with excellent processing and forming properties. Through melt extrusion and calendering of this mixture, a waterproof and breathable film with excellent mechanical properties and moisture permeability can be obtained. The thickness of this waterproof and breathable film is not more than 0.7 mm, the longitudinal tensile breaking strength is greater than 450 N / 50 mm, the transverse elongation at break is greater than 50%, and the moisture permeability is greater than 4.0×10 -7 g / (m 2 ·s·Pa). Specific Embodiments

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] In a first aspect, the present invention provides a preparation method of a waterproof and breathable film, and the preparation method includes:

[0030] Mix the polymer resin masterbatch, lubricant, and additives to obtain a mixture; the additives include at least one of an antioxidant and a catalyst; the dosage of the lubricant is 0.5 - 1.5 wt% of the polymer resin masterbatch; the dosage of the additives is 0.1 - 0.5 wt% of the polymer resin masterbatch;

[0031] Perform melt extrusion and calendering on the mixture to obtain a waterproof and breathable film.

[0032] By controlling the dosages of the polymer resin masterbatch, lubricant, and additives, the present invention obtains a mixture with excellent processing and forming properties. Through melt extrusion and calendering of this mixture, a waterproof and breathable film with excellent mechanical properties and moisture permeability can be obtained.

[0033] According to some preferred embodiments, the dosage of the lubricant is 0.5 to 1 wt% of the polymer resin masterbatch (for example, it can be 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt% or 1 wt%).

[0034] The dosage of the auxiliary agent is 0.1 to 0.2 wt% of the polymer resin masterbatch (for example, it can be 0.1 wt%, 0.12 wt%, 0.14 wt%, 0.15 wt%, 0.16 wt%, 0.18 wt% or 0.2 wt%).

[0035] According to some preferred embodiments, the polymer resin masterbatch is selected from one or more of polyester, polyurethane and polytetrafluoroethylene.

[0036] According to some preferred embodiments, the lubricant is one or more of methyl silicone oil, ethyl silicone oil, stearic acid amide, oleic acid amide, microcrystalline wax, polyethylene wax.

[0037] According to some preferred embodiments, the antioxidant is one or more of mercaptoethanol, mercaptopropanol, 2,6-di-tert-butyl-p-cresol (BHT), tert-butyl-4-hydroxyanisole (BHA), tert-butylhydroquinone (TBHQ).

[0038] According to some preferred embodiments, the catalyst is one or more of peroxide catalysts and basic catalysts.

[0039] According to some preferred embodiments, the peroxide catalyst is one or more of benzoyl peroxide and dicumyl peroxide; the basic catalyst is one or more of dimethylaniline, triethanolamine, sodium hydroxide, potassium hydroxide;

[0040] According to some preferred embodiments, the melt extrusion is achieved by a twin-screw extruder. During the melt extrusion process, the rotational speed of the twin-screw is 60 to 80 r / min (for example, it can be 60 r / min, 65 r / min, 70 r / min, 75 r / min or 80 r / min), and the feeding speed is 5 to 15 g / min (for example, it can be 5 g / min, 10 g / min or 15 g / min); under the condition that other conditions are the same, if the rotational speed of the screw is too large, the extrusion volume will be relatively small, the thickness of the produced film will be small, although the gas permeability performance becomes better, but the mechanical properties become worse; if the feeding speed is too large, the extrusion volume will be relatively large, the thickness of the produced film will be large, although the mechanical properties become better, but the gas permeability performance becomes worse. In order to balance the mechanical properties and gas permeability performance of the produced film, the present invention controls the rotational speed of the twin-screw and the feeding speed within the above ranges.

[0041] The twin-screw extruder includes a first temperature zone, a second temperature zone, and a third temperature zone with gradually increasing temperatures along the forward rotation direction of the screw. The temperature of the first temperature zone is 190 - 200 °C (for example, it can be 190 °C, 195 °C, or 200 °C), the temperature of the second temperature zone is 200 - 210 °C (for example, it can be 200 °C, 205 °C, or 210 °C), and the temperature of the third temperature zone is 205 - 220 °C (for example, it can be 205 °C, 210 °C, 215 °C, or 220 °C).

[0042] According to some preferred embodiments, the calendering is achieved by a three-roll calender and a haul-off roll;

[0043] The temperature of the upper roll of the three-roll calender is 180 - 200 °C (for example, it can be 180 °C, 185 °C, 190 °C, 195 °C, or 200 °C), and the rotational speed is 20 - 22 rpm;

[0044] The temperature of the middle roll of the three-roll calender is 175 - 200 °C (for example, it can be 175 °C, 180 °C, 185 °C, 190 °C, 195 °C, or 200 °C), and the rotational speed is 21.5 - 23.5 rpm;

[0045] The temperature of the lower roll of the three-roll calender is 170 - 195 °C (for example, it can be 175 °C, 180 °C, 185 °C, 190 °C, or 195 °C), and the rotational speed is 23 - 24 rpm;

[0046] The rotational speed of the haul-off roll of the three-roll calender is 23 - 29 rpm.

[0047] In the present invention, by measuring the glass transition temperature and melting temperature of the mixture, and determining the temperature ranges for melt extrusion and calendering during the calendering process based on the glass transition temperature and melting temperature, and combining the analysis results of the mechanical properties of the mixture, the screw rotational speed, feeding speed, and temperature ranges of each temperature zone during the melt extrusion process, as well as the temperatures and rotational speeds of each calender roll during the calendering process, are determined and optimized to ensure obtaining a waterproof and breathable film with excellent performance. Therefore, the parameters of melt extrusion and calendering in the present invention are controlled within the above ranges.

[0048] In a second aspect, the present invention provides a waterproof and breathable film prepared by using the preparation method described in the first aspect.

[0049] The thickness of the waterproof and breathable film provided by the present invention is not greater than 0.7 mm, the longitudinal tensile fracture strength is greater than 450 N / 50 mm, the transverse fracture elongation rate is greater than 50%, and the water vapor transmission rate is greater than 4.0×10 -7 g / (m 2 ·s·Pa).

[0050] The present invention provides, in a second aspect, an application of the waterproof and breathable film described in the second aspect, which is applied to the fields of construction, electronics, medicine, and textiles.

[0051] To more clearly illustrate the technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with embodiments. The present invention does not specifically limit the sources of the various reagents used in the examples and comparative examples, and they can be directly purchased or synthesized by oneself.

[0052] Example 1

[0053] (1) Polyurethane, methyl silicone oil, and benzoyl peroxide were mixed in a mass ratio of 100:1:0.2, and the rotation speed of the magnetic stirrer was set at 1000 r / min, and stirred for 10 min. The mixture was placed in a twin-screw extruder for melt extrusion at a feeding speed of 10 g / min. Among them, the temperature of the first temperature zone along the forward direction of the screw rotation was 190 °C, the temperature of the second temperature zone was 200 °C, the temperature of the third temperature zone was 210 °C, and the screw rotation speed was 60 rpm.

[0054] (2) The melt-extruded material was placed in a calender for calendering. During the calendering process, the temperature of the upper roll of the calender was controlled at 190 °C, the rotation speed was 21 rpm, the temperature of the middle roll was 180 °C, the rotation speed was 21.5 rpm, the temperature of the lower roll was 175 °C, the rotation speed was 23 rpm, and the rotation speed of the traction roll was 25 rpm to obtain a waterproof and breathable film.

[0055] The thickness of the waterproof and breathable film material prepared in this example was 0.65 mm, the longitudinal tensile fracture strength was 460 N / 50 mm, the transverse elongation at break was 55%, and the moisture permeability was 4.5×10 -7 g / (m 2 ·s·Pa).

[0056] Example 2

[0057] (1) Polyester, microcrystalline wax, and mercaptopropanol were mixed in a mass ratio of 100:0.5:0.1, and the rotation speed of the magnetic stirrer was set at 1500 r / min, and stirred for 20 min. The mixture was placed in a twin-screw extruder for melt extrusion at a feeding speed of 13 g / min. Among them, the temperature of the first temperature zone along the forward direction of the screw rotation was 195 °C, the temperature of the second temperature zone was 200 °C, the temperature of the third temperature zone was 205 °C, and the screw rotation speed was 68 rpm.

[0058] (2) Place the material after melt extrusion in a calender and perform calendering. During the calendering process, control the temperature of the upper roll of the calender at 180 °C, the rotation speed at 20 rpm, the temperature of the middle roll at 175 °C, the rotation speed at 22 rpm, the temperature of the lower roll at 170 °C, the rotation speed at 23 rpm, and the rotation speed of the traction roll at 25 rpm to obtain a waterproof and breathable film.

[0059] In this example, the thickness of the obtained waterproof and breathable film material is 0.6 mm, the longitudinal tensile fracture strength is 480 N / 50 mm, the transverse fracture elongation rate is 63%, and the moisture permeability rate is 4.7×10 -7 g / (m 2 ·s·Pa).

[0060] Example 3

[0061] (1) Mix polytetrafluoroethylene, methyl silicone oil, and sodium hydroxide in a mass ratio of 100:1:0.1, set the rotation speed of the magnetic stirrer at 2000 r / min, stir for 5 min, and place the mixture in a twin-screw extruder for melt extrusion at a feeding speed of 6 g / min. Among them, the temperature of the first temperature zone along the forward direction of the screw rotation is 200 °C, the temperature of the second temperature zone is 210 °C, the temperature of the third temperature zone is 220 °C, and the screw rotation speed is 80 rpm.

[0062] (2) Place the material after melt extrusion in a calender and perform calendering. During the calendering process, control the temperature of the upper roll of the calender at 200 °C, the rotation speed at 22 rpm, the temperature of the middle roll at 200 °C, the rotation speed at 23.5 rpm, the temperature of the lower roll at 195 °C, the rotation speed at 24 rpm, and the rotation speed of the traction roll at 25 rpm to obtain a waterproof and breathable film.

[0063] In this example, the thickness of the obtained waterproof and breathable film material is 0.68 mm, the longitudinal tensile fracture strength is 460 N / 50 mm, the transverse fracture elongation rate is 57%, and the moisture permeability rate is 4.2×10 -7 g / (m 2 ·s·Pa).

[0064] Comparative Example 1

[0065] It is basically the same as Example 1, except that: in step (1), methyl silicone oil and benzoyl peroxide are not added.

[0066] In this comparative example, the thickness of the obtained waterproof and breathable film material is 0.69 mm, the longitudinal tensile fracture strength is 380 N / 50 mm, the transverse fracture elongation rate is 35%, and the moisture permeability rate is 2.5×10 -7 g / (m 2 ·s·Pa).

[0067] Comparative Example 2

[0068] It is basically the same as Example 1, except that benzoyl peroxide is not added in step (1).

[0069] The thickness of the waterproof and breathable film material prepared in this comparative example is 0.65 mm, the longitudinal tensile fracture strength is 400 N / 50 mm, the transverse elongation at break is 45%, and the water vapor permeability is 3.8×10 -7 g / (m 2 ·s·Pa).

[0070] Comparative Example 3

[0071] It is basically the same as Example 1, except that methyl silicone oil is not added in step (1).

[0072] The thickness of the waterproof and breathable film material prepared in this comparative example is 0.71 mm, the longitudinal tensile fracture strength is 430 N / 50 mm, the transverse elongation at break is 52%, and the water vapor permeability is 2.9×10 -7 g / (m 2 ·s·Pa).

[0073] Comparative Example 4

[0074] It is basically the same as Example 1, except that the mass ratio of polyurethane, methyl silicone oil, and benzoyl peroxide in step (1) is 100:2:0.2.

[0075] The thickness of the waterproof and breathable film material prepared in this comparative example is 0.58 mm, the longitudinal tensile fracture strength is 390 N / 50 mm, the transverse elongation at break is 46%, and the water vapor permeability is 4.8×10 -7 g / (m 2 ·s·Pa).

[0076] Comparative Example 5

[0077] It is basically the same as Example 2, except that microcrystalline wax and mercaptopropanol are not added in step (1).

[0078] The thickness of the waterproof and breathable film material prepared in this comparative example is 0.62 mm, the longitudinal tensile fracture strength is 400 N / 50 mm, the transverse elongation at break is 56%, and the water vapor permeability is 4.1×10 -7 g / (m 2 ·s·Pa).

[0079] Comparative Example 6

[0080] It is basically the same as Example 2, except that mercaptopropanol is not added in step (1).

[0081] The thickness of the waterproof and breathable film material prepared in this comparative example is 0.67 mm, the longitudinal tensile fracture strength is 510 N / 50 mm, the transverse elongation at break is 66%, and the moisture permeability is 3.7×10 -7 g / (m 2 ·s·Pa).

[0082] Comparative Example 7

[0083] It is basically the same as Example 2, except that: microcrystalline wax was not added in step (1).

[0084] The thickness of the waterproof and breathable film material prepared in this comparative example is 0.7 mm, the longitudinal tensile fracture strength is 680 N / 50 mm, the transverse elongation at break is 69%, and the moisture permeability is 2.7×10 -7 g / (m 2 ·s·Pa).

[0085] Comparative Example 8

[0086] It is basically the same as Example 2, except that: the mass ratio of polyester, microcrystalline wax, and mercaptopropanol in step (1) is 100:0.2:0.1.

[0087] The thickness of the waterproof and breathable film material prepared in this comparative example is 0.72 mm, the longitudinal tensile fracture strength is 520 N / 50 mm, the transverse elongation at break is 68%, and the moisture permeability is 1.7×10 -7 g / (m 2 ·s·Pa).

[0088] Comparative Example 9

[0089] It is basically the same as Example 3, except that: methyl silicone oil and sodium hydroxide were not added in step (1).

[0090] The thickness of the waterproof and breathable film material prepared in this comparative example is 0.74 mm, the longitudinal tensile fracture strength is 560 N / 50 mm, the transverse elongation at break is 62%, and the moisture permeability is 3.5×10 -7 g / (m 2 ·s·Pa).

[0091] Comparative Example 10

[0092] It is basically the same as Example 3, except that: sodium hydroxide was not added in step (1).

[0093] The thickness of the waterproof and breathable film material prepared in this comparative example is 0.67 mm, the longitudinal tensile fracture strength is 420 N / 50 mm, the transverse elongation at break is 49%, and the moisture permeability is 3.8×10 -7 g / (m 2 ·s·Pa).

[0094] Comparative Example 11

[0095] It is basically the same as Example 3, except that: methyl silicone oil was not added in step (1).

[0096] The thickness of the waterproof and breathable film material prepared in this comparative example is 0.71 mm, the longitudinal tensile fracture strength is 490 N / 50 mm, the transverse elongation at break is 59%, and the water vapor transmission rate is 3.6×10 -7 g / (m 2 ·s·Pa).

[0097] Comparative Example 12

[0098] It is basically the same as Example 3, except that: the mass ratio of polytetrafluoroethylene, methyl silicone oil, and sodium hydroxide in step (1) is 100:3:0.1.

[0099] The thickness of the waterproof and breathable film material prepared in this comparative example is 0.60 mm, the longitudinal tensile fracture strength is 385 N / 50 mm, the transverse elongation at break is 48%, and the water vapor transmission rate is 4.4×10 -7 g / (m 2 ·s·Pa).

[0100] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for preparing a waterproof vapor-permeable membrane, characterized in that: The preparation method comprises: The polymer resin masterbatch, lubricant and auxiliary agent are mixed to obtain a mixture; the auxiliary agent includes at least one of an antioxidant and a catalyst; the amount of the lubricant is 0.5-1.5wt% of the polymer resin masterbatch; the amount of the auxiliary agent is 0.1-0.5wt% of the polymer resin masterbatch; The mixture is melt-extruded and calendered to obtain a waterproof vapor-permeable membrane.

2. The preparation method according to claim 1, characterized in that: The amount of the lubricant is 0.5-1 wt % of the polymer resin masterbatch.

3. The preparation method according to claim 1, characterized in that: The dosage of the auxiliary agent is 0.1-0.2 wt % of the polymer resin masterbatch.

4. The preparation method according to claim 1, characterized in that: The polymer resin masterbatch is selected from one or more of polyester, polyurethane and polytetrafluoroethylene; and / or The lubricant is one or more of methyl silicone oil, ethyl silicone oil, stearic acid amide, oleic acid amide, microcrystalline wax, and polyethylene wax.

5. The preparation method according to claim 1, characterized in that: The antioxidant is one or more of mercaptoethanol, mercaptopropanol, 2,6-di-tert-butyl-p-cresol, tert-butyl-4-hydroxyanisole, and tert-butylhydroquinone; and / or The catalyst is one or more of a peroxide catalyst and an alkaline catalyst.

6. The preparation method according to claim 1, characterized in that: The peroxide catalyst is one or more of benzoyl peroxide and dicumyl peroxide; and / or The alkaline catalyst is one or more of dimethylaniline, triethanolamine, sodium hydroxide and potassium hydroxide.

7. The preparation method according to claim 1, characterized in that: The melt extrusion is achieved by a twin-screw extruder, the twin-screw speed during the melt extrusion process is 60-80r / min, and the feeding rate is 5-15g / min; The twin-screw extruder comprises a first temperature zone, a second temperature zone and a third temperature zone, the temperatures of which increase successively along the rotating direction of the screw. The temperature of the first temperature zone is 190-200°C, the temperature of the second temperature zone is 200-210°C, and the temperature of the third temperature zone is 205-220°C.

8. The preparation method according to claim 1, characterized in that: The calendering is achieved by a three-roll calender; The upper roller temperature of the three-roll calender is 180-200°C and the rotation speed is 20-22 rpm; The middle roll temperature of the three-roll calender is 175-200°C and the rotation speed is 21.5-23.5rpm; The temperature of the lower roll of the three-roll calender is 170-195°C and the rotation speed is 23-24 rpm; The rotation speed of the traction roller of the three-roll calender is 23-29 rpm.

9. A waterproof vapor permeable membrane, characterized in that: The method is prepared by the method according to any one of claims 1 to 8.

10. An application of the waterproof vapor-permeable membrane according to claim 9, characterized in that: Used in construction, electronics, medical and textile fields.