High-barrier film material for hazardous chemical protective clothing and preparation method thereof

Abstract

The present application belongs to the technical field of film, especially to a high-barrier film material for hazardous chemical protective clothing and a preparation method thereof. The material is connected in order by co-extrusion of an outer layer, a secondary outer layer, a core layer outer adhesive layer, a core layer barrier layer, a core layer inner adhesive layer, a secondary inner layer and an inner layer. The present application adopts a blow molding method, and the film is stretched in different degrees in the transverse and longitudinal directions in the blow molding process, thereby greatly improving the temperature resistance.

Description

Technical Field

[0001] This invention relates to the field of thin film technology, and in particular to a high-barrier membrane material for chemical protective clothing and its preparation method. Background Technology

[0002] In recent years, protective clothing for medical and health use, chemical production, and microbiology laboratories has been widely used. However, most of the hazardous materials protective clothing on the market is finished garments made of non-woven fabric with a highly breathable membrane. While these garments are soft and breathable and moisture-permeable, they lack the ability to block common hazardous chemicals in laboratories, such as strong acids, strong alkalis, and heavy metal ions. Various hazardous materials are frequently encountered during laboratory experiments. To meet the ever-increasing demands of laboratory experiments, protect the health and safety of laboratory personnel, and meet laboratory health and hygiene requirements, [further measures are needed].

[0003] Currently, the environmental protection measures provided to laboratory technicians in China are still mainly ordinary plastic gloves or bulky PU leather protective clothing. Ordinary plastic gloves are lightweight, convenient, breathable, and moisture-permeable, but their protection against hazardous chemicals in experiments is negligible, and laboratory safety incidents still occur frequently. While PU leather protective clothing offers good acid and alkali resistance and the ability to isolate heavy metal ions, ensuring the safety of laboratory personnel, laboratory operations are precision processes, and PU leather protective clothing is bulky and has poor permeability, making it unsuitable for laboratory personnel to perform experiments. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a high-barrier membrane material for chemical protective clothing and its preparation method, which improves the acid and alkali resistance and corrosion resistance of laboratory chemical protective clothing and gloves, and solves the problem of inconvenience for laboratory personnel caused by the heavy isolation materials of ordinary chemical protective clothing.

[0005] To achieve one of the objectives of this invention, this invention provides a high-barrier membrane material for hazardous chemical protective clothing: the material is co-extruded by sequentially connecting an outer layer, a sub-outer layer, a core outer adhesive layer, a core barrier layer, a core inner adhesive layer, a sub-inner layer, and an inner layer; the outer and inner layers are both composed of polypropylene random copolymer, propylene-based elastomer, and polyolefin functional masterbatch in a mass ratio of (59-69):(30-40):1; the sub-outer and sub-inner layers are both composed of metallocene linear low-density polyethylene, propylene-based elastomer, and polyolefin functional masterbatch in a mass ratio of (59-69):(30-40):1; the core outer adhesive layer and the core inner adhesive layer are both composed of 100% maleic anhydride-modified polyethylene by mass; the core barrier layer is composed of 100% ethylene-vinyl alcohol copolymer by mass.

[0006] Preferably, the outer layer, the second outer layer, the outer adhesive layer of the core layer, the core layer barrier layer, the inner adhesive layer of the core layer, the second inner layer and the inner layer are composed of a layer thickness ratio of (6-11):(4-8):(4-5):(5-8):(4-5):(4-8):(6-11).

[0007] Preferably, the total thickness of the material is 35-55 μm.

[0008] Preferably, the melt index of the random copolymer of polypropylene is 1.5-3.0 g / 10 min 190℃ / 2.16 kg; the melt index of the propylene-based elastomer is 2.0-5.0 g / 10 min 190℃ / 2.16 kg; the melt index of the polyolefin functional masterbatch is 3.8-5.5 g / 10 min 190℃ / 2.16 kg; the melt index of the metallocene linear low-density polyethylene is 0.3-0.5 g / 10 min 190℃ / 2.16 kg; the melt index of the maleic anhydride modified polyethylene is 2.8-3.5 g / 10 min 190℃ / 2.16 kg; and the melt index of the ethylene-vinyl alcohol copolymer is 1.0-3.0 g / 10 min 190℃ / 2.16 kg.

[0009] Preferably, the density of the random copolymer of polypropylene is 0.90-0.91 g / cm³. 3 The flexural modulus is 850-950 MPa; the density of metallocene linear low-density polyethylene is 0.912-0.918 g / cm³. 3 The density of propylene-based elastomers is 0.879-0.902 g / cm³. 3 The density of the ethylene-vinyl alcohol copolymer is 1.10-1.20 g / cm³. 3 .

[0010] Preferably, the grade of the polypropylene random copolymer is RB707CF manufactured by Borealis; the grade of the propylene-based elastomer is 3980FL manufactured by ExxonMobil; the grade of the metallocene linear low-density polyethylene is 2005MA manufactured by ExxonMobil; the grade of the maleic anhydride modified polyethylene is NF908 manufactured by Mitsui Chemicals, Inc.; and the grade of the ethylene-vinyl alcohol copolymer is ET3203RB manufactured by Kuraray Co., Ltd.

[0011] Preferably, the polyolefin functional masterbatch mixture consists of two polyolefin functional masterbatches in a mass ratio of 1:1, one of which is a polyolefin functional masterbatch of grade 100991-K produced by Anpeise Company, and the other is a polyolefin functional masterbatch of SLP-7 produced by Beijing Yalen Company.

[0012] Preferably, the outer and inner layers are composed of polypropylene random copolymer, propylene-based elastomer, and polyolefin functional masterbatch in a mass ratio of 64:35:1; the second outer and second inner layers are composed of metallocene linear low-density polyethylene, propylene-based elastomer, and polyolefin functional masterbatch in a mass ratio of 64:36:1.

[0013] To achieve the second objective of this invention, this invention provides a method for preparing a high-barrier membrane material for chemical protective clothing used with hazardous chemicals. This preparation method includes the following steps:

[0014] S1. The materials of each layer are fed into the barrel of the blown film machine for melt co-extrusion. The temperature of the melt section of the blown film machine is 40-80℃, the temperature of the extrusion section is 190-245℃, the temperature of the die head is 245℃, the extrusion rate is 460-560kg / h, and the blow-up ratio is 1:(1.2-2.5) to form a film bubble and obtain a seven-layer co-extruded blown film.

[0015] S2. The seven-layer co-extruded blown film is then sequentially traction, cooling, shaping, trimming, and winding to obtain a high-barrier film material.

[0016] Preferably, after the membrane bubble is cooled and crystallized by internal air circulation at a temperature of 14-25℃, the first traction tension is 100N, the second traction tension is 200N, and the center winding and pressing force is 200N.

[0017] The machining screw temperatures for the outer layer, the second outer layer, the outer adhesive layer of the core layer, the core barrier layer, the inner adhesive layer of the core layer, the second inner layer, and the inner layer are 210℃, 205℃, 230℃, 240℃, 230℃, 205℃, and 210℃, respectively.

[0018] The advantages of this invention compared to the prior art are as follows:

[0019] 1) This invention adopts a seven-layer co-extrusion blow molding process. The core layer uses ethylene polyvinyl alcohol copolymer. Compared with the two stretching molding processes of the casting co-extrusion method, the blow molding process removes less edge material, which greatly reduces the production cost. At the same time, the film produced by the blow molding process has higher tensile strength and better strength properties.

[0020] 2) This invention utilizes the stiffness of polypropylene random copolymer and its good adhesion to nonwoven materials, combines the high barrier properties of ethylene-vinyl alcohol copolymer (EVOH) material with the high toughness of polypropylene elastomer, and improves the crumpling performance of the film; the use of maleic anhydride modified polyethylene enables various materials to be bonded together better.

[0021] 3) The film is produced through a seven-layer co-extrusion process. The outer layer film exhibits excellent processing performance and light transmittance; the middle layer film provides good thermal adhesion, stiffness, and flexibility; and the core layer film serves as a barrier layer, possessing excellent oxygen barrier, water barrier, and acid and alkali resistance properties. This film demonstrates superior performance in tensile strength, moisture barrier properties, oxygen barrier properties, puncture resistance, heat-sealing and thermal adhesion properties, rubbing resistance, antistatic properties, softness, acid and alkali resistance, and oil resistance. Furthermore, this invention employs a blow molding method, where the film undergoes varying degrees of stretching in both the transverse and longitudinal directions during the blowing process, significantly improving the film's temperature resistance. The preparation method of this invention considers market demands and characteristics, focusing on raw material selection, proportioning, and process parameters.

[0022] 4) Ethylene-vinyl alcohol copolymer (EVOH) is a chain-structured crystalline polymer that combines the excellent processability of ethylene polymers with the extremely high barrier properties of polyvinyl alcohol, making it a novel high-barrier material. Its barrier properties are 100 times higher than those of commonly available polyamides (PA). Furthermore, EVOH exhibits excellent performance in terms of stretchability, abrasion resistance, and cold resistance. This invention designs a seven-layer co-extruded high-barrier film of EVOH, which combines excellent acid and alkali resistance with lightweight, breathable, and convenient movement.

[0023] 5) The high-barrier membrane material for hazardous chemicals designed in this invention provides strong protection against safety risks in laboratory environments, and achieves a barrier rate of up to 99.9% against common laboratory chemicals such as nitric acid, perchloric acid, sulfuric acid, hydroiodic acid, hydrobromic acid, permanganic acid, hydrochloric acid, chloric acid, lithium hydroxide, sodium hydroxide, potassium hydroxide, and barium hydroxide. It also provides protection against common heavy metal ions such as Cr. 6+ Te 3+ Co 3+ Se 3+ Hg 2+ Mn 4+ It also has a certain barrier effect. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0025] The composition of each layer of a high-barrier membrane material for hazardous chemical protective clothing is shown in Table 1 below:

[0026] Table 1

[0027]

[0028]

[0029] The ethylene monomer content in the ethylene-vinyl alcohol copolymer in the core barrier layer is 32%.

[0030] Example 1

[0031] S1. Weigh the outer layer components according to the mass ratio of polypropylene random copolymer, propylene-based elastomer, and polyolefin functional masterbatch in a ratio of 64:35:1; weigh the second outer layer components according to the mass ratio of metallocene linear low-density polyethylene, propylene-based elastomer, and polyolefin functional masterbatch in a ratio of 64:35:1; weigh the outer adhesive layer and inner adhesive layer of the core layer with 100% maleic anhydride modified polyethylene by mass; weigh the barrier layer of the core layer with 100% ethylene-vinyl alcohol copolymer by mass.

[0032] S2. The seven-layer components weighed above are fed into the blown film machine barrel according to the material particle ratio for melt co-extrusion. The melting section temperature of the blown film machine is 55℃, and the temperatures of the seven layers from the outside to the inside of the extruder are 210℃, 205℃, 230℃, 240℃, 230℃, 205℃, and 210℃ respectively. The die head temperature is 240℃, and the extrusion rate is 482kg / h, thus obtaining a seven-layer co-extruded blown film.

[0033] S3. The seven-layer co-extruded blown film is blown at a ratio of 1:1.6. The thickness of the blown film after cooling is 40μm, of which the outer layer is 8.5μm, the second outermost adhesive layer is 5μm, the outer core layer adhesive layer is 4μm, the core barrier layer is 6μm, the inner core layer adhesive layer is 4μm, the second innermost layer is 4μm, and the innermost layer is 8.5μm. After cooling, shaping, trimming, and winding, high barrier film material 1 is obtained.

[0034] Example 2

[0035] S1. Weigh the outer layer components according to the mass ratio of polypropylene random copolymer, propylene-based elastomer, and polyolefin functional masterbatch in a ratio of 59:40:1; weigh the second outer layer components according to the mass ratio of metallocene linear low-density polyethylene, propylene-based elastomer, and polyolefin functional masterbatch in a ratio of 59:40:1; weigh the outer adhesive layer and inner adhesive layer of the core layer with 100% maleic anhydride modified polyethylene by mass; weigh the barrier layer of the core layer with 100% ethylene-vinyl alcohol copolymer by mass.

[0036] S2. The seven-layer components weighed above are fed into the blown film machine barrel according to the material particle ratio for melt co-extrusion. The melting section temperature of the blown film machine is 55℃, and the temperatures of the seven layers from the outside to the inside of the extruder are 220℃, 215℃, 230℃, 240℃, 230℃, 215℃, and 220℃ respectively. The die head temperature is 235℃, and the extrusion rate is 500kg / h, thus obtaining a seven-layer co-extruded blown film.

[0037] S3. The seven-layer co-extruded blown film is blown at a ratio of 1:1.8. The thickness of the blown film after cooling is 50μm, of which the outer layer is 10μm, the second outermost adhesive layer is 8μm, the outer core adhesive layer is 4μm, the core barrier layer is 6μm, the inner core adhesive layer is 4μm, the second innermost layer is 8μm, and the innermost layer is 10μm. After sequentially passing through traction, cooling, shaping, edge trimming, and winding, high barrier film material 2 is obtained.

[0038] Example 3

[0039] S1. Weigh the outer layer components according to the mass ratio of polypropylene random copolymer, propylene-based elastomer, and polyolefin functional masterbatch in a ratio of 69:30:1; weigh the second outer layer components according to the mass ratio of metallocene linear low-density polyethylene, propylene-based elastomer, and polyolefin functional masterbatch in a ratio of 69:30:1; weigh the outer adhesive layer and inner adhesive layer of the core layer with 100% maleic anhydride modified polyethylene by mass; weigh the barrier layer of the core layer with 100% ethylene-vinyl alcohol copolymer by mass.

[0040] S2. The seven-layer components weighed above are fed into the blown film machine barrel according to the material particle ratio for melt co-extrusion. The melting section temperature of the blown film machine is 60℃, and the temperatures of the seven layers from the outside to the inside of the extruder are 220℃, 220℃, 230℃, 235℃, 230℃, 220℃, and 220℃ respectively. The die head temperature is 235℃, and the extrusion rate is 515kg / h, thus obtaining a seven-layer co-extruded blown film.

[0041] S3. The seven-layer co-extruded blown film is blown into shape with a blown film ratio of 1:2.0. The thickness of the blown film after cooling is 45μm, of which the outer layer is 9μm, the second outermost adhesive layer is 6μm, the outer core layer adhesive layer is 4μm, the core barrier layer is 7μm, the inner core layer adhesive layer is 4μm, the second innermost layer is 6μm, and the innermost layer is 9μm. After sequentially passing through traction, cooling, shaping, edge trimming, and winding, a high barrier film material 3 is obtained.

[0042] Example 4

[0043] S1. Weigh the outer layer components according to the mass ratio of polypropylene random copolymer, propylene-based elastomer, and polyolefin functional masterbatch in a ratio of 63:36:1; weigh the second outer layer components according to the mass ratio of metallocene linear low-density polyethylene, propylene-based elastomer, and polyolefin functional masterbatch in a ratio of 63:36:1; weigh the outer adhesive layer and inner adhesive layer of the core layer with 100% maleic anhydride modified polyethylene by mass; weigh the barrier layer of the core layer with 100% ethylene-vinyl alcohol copolymer by mass.

[0044] S2. The seven-layer components weighed above are fed into the blown film machine barrel according to the material particle ratio for melt co-extrusion. The melting section temperature of the blown film machine is 60℃, and the temperatures of the seven layers from the outside to the inside of the extruder are 215℃, 215℃, 220℃, 238℃, 220℃, 215℃, and 215℃ respectively. The die temperature is 240℃, and the extrusion rate is 550kg / h, thus obtaining a seven-layer co-extruded blown film.

[0045] S3. The seven-layer co-extruded blown film is blown at a ratio of 1:2.2. The thickness of the blown film after cooling is 55μm, of which the outer layer is 11μm, the second outermost adhesive layer is 7.5μm, the outer core adhesive layer is 5μm, the core barrier layer is 8μm, the inner core adhesive layer is 5μm, the second innermost layer is 7.5μm, and the innermost layer is 11μm. After sequentially passing through traction, cooling, shaping, edge trimming, and winding, a high barrier film material 4 is obtained.

[0046] Example 5

[0047] S1. Weigh the outer layer components according to the mass ratio of polypropylene random copolymer, propylene-based elastomer, and polyolefin functional masterbatch in a ratio of 67:32:1; weigh the second outer layer components according to the mass ratio of metallocene linear low-density polyethylene, propylene-based elastomer, and polyolefin functional masterbatch in a ratio of 67:32:1; weigh the outer adhesive layer and inner adhesive layer of the core layer with 100% maleic anhydride modified polyethylene by mass; weigh the barrier layer of the core layer with 100% ethylene-vinyl alcohol copolymer by mass.

[0048] S2. The seven-layer components weighed above are fed into the blown film machine barrel according to the particle ratio for melt co-extrusion. The melting section temperature of the blown film machine is 62℃, and the temperatures of the seven layers from the outside to the inside of the extruder are 210℃, 205℃, 220℃, 230℃, 220℃, 205℃, and 210℃ respectively. The die temperature is 235℃, and the extrusion rate is 458kg / h, thus obtaining a seven-layer co-extruded blown film.

[0049] S3. The seven-layer co-extruded blown film is blown at a ratio of 1:1.8. The thickness of the blown film after cooling is 35μm, of which the outer layer is 6μm, the second outermost adhesive layer is 4.5μm, the outer core layer adhesive layer is 4μm, the core barrier layer is 6μm, the inner core layer adhesive layer is 4μm, the second innermost layer is 4.5μm, and the innermost layer is 6μm. After cooling, shaping, trimming, and winding, a high barrier film material 5 is obtained.

[0050] Table 2 below shows the sources of the granules used in Examples 1-5:

[0051] Table 2

[0052]

[0053]

[0054] The high-barrier membrane materials prepared in the above embodiments were subjected to performance tests, and the results are shown in Table 3 below:

[0055] Table 3

[0056]

[0057] Tensile strength is used to measure the toughness, tensile strength, and tear resistance of finished garments, among other things.

[0058] 5% tensile strength: Used to measure the garment's resistance to deformation;

[0059] Elongation at break (%): can be used to determine the toughness and resistance to deformation of the film;

[0060] Right-angle tear: Used to measure a garment's resistance to rubbing, toughness, and tear resistance;

[0061] The coefficient of friction affects the machine's movement performance and the strength of the composite bond during processing.

[0062] Water vapor permeability and oxygen permeability are used to determine the barrier properties of a membrane.

[0063] As shown in Table 3, the high-barrier membrane materials prepared in Examples 1-5 exhibit superior tensile strength, 5% tensile force, elongation at break (%), coefficient of friction, right-angle tear resistance, barrier properties, and pH tolerance compared to existing PE protective clothing. Furthermore, the high-barrier membrane materials prepared in Examples 1-5, when combined with non-woven fabrics to obtain composite films, all passed 15,000 rubbing tests and aging and penetration tests with over 200 chemicals, showing no pinholes and thus being a viable alternative to imported products.

[0064] This invention utilizes a blow molding process to produce a high-barrier membrane material, which exhibits significant advantages in tensile strength, coefficient of friction, oxygen permeability, water vapor permeability, and pH tolerance range. Performance test results of the high-barrier membrane materials in Examples 1-5 demonstrate that the high-barrier membrane material designed in this invention provides strong protection against safety risks present in laboratory environments. Furthermore, it achieves a barrier rate of up to 99.9% against common laboratory strong acids and bases such as nitric acid, perchloric acid, sulfuric acid, hydroiodic acid, hydrobromic acid, permanganic acid, hydrochloric acid, chloric acid, lithium hydroxide, sodium hydroxide, potassium hydroxide, and barium hydroxide. It also provides protection against common heavy metal ions such as Cr. 6+ Te 3+ Co 3+ Se 3+ Hg 2+ Mn 4+It also provides some barrier properties. Furthermore, the film's thinness, breathability, and moisture permeability are significant advantages, perfectly aligning with the industry's future development.

Claims

1. A high-barrier membrane material for chemical protective clothing, characterized in that, The material is co-extruded from an outer layer, a second outer layer, an outer core layer adhesive layer, a core layer barrier layer, an inner core layer adhesive layer, a second inner layer, and an inner layer in sequence; the outer core layer adhesive layer and the inner core layer adhesive layer are both composed of 100% maleic anhydride modified polyethylene by mass; the core layer barrier layer is composed of 100% ethylene-vinyl alcohol copolymer by mass. The outer and inner layers are both composed of a mixture of polypropylene random copolymer, propylene-based elastomer, and polyolefin functional masterbatch in a mass ratio of 64:35:1; the secondary outer and secondary inner layers are both composed of a mixture of metallocene linear low-density polyethylene, propylene-based elastomer, and polyolefin functional masterbatch in a mass ratio of 64:35:

1.

2. The high-barrier membrane material for chemical protective clothing according to claim 1, characterized in that, The outer layer, the second outer layer, the outer adhesive layer of the core layer, the core layer barrier layer, the inner adhesive layer of the core layer, the second inner layer, and the inner layer are composed of a layer thickness ratio of (6-10):(4-7):(4-5):(7-8):(4-5):(4-7):(6-10).

3. The high-barrier membrane material for chemical protective clothing according to claim 1, characterized in that, The total thickness of the material is 35-55 μm.

4. The high-barrier membrane material for chemical protective clothing according to claim 1, characterized in that, The melt index of the polypropylene random copolymer is 1.5-3.0 g / 10 min, 190℃ / 2.16 kg; the melt index of the propylene-based elastomer is 2.0-5.0 g / 10 min, 190℃ / 2.16 kg; the melt index of the polyolefin functional masterbatch mixture is 3.8-5.5 g / 10 min, 190℃ / 2.16 kg; the melt index of the metallocene linear low-density polyethylene is 0.3-0.5 g / 10 min, 190℃ / 2.16 kg; the melt index of the maleic anhydride modified polyethylene is 2.8-3.5 g / 10 min, 190℃ / 2.16 kg; and the melt index of the ethylene-vinyl alcohol copolymer is 1.0-3.0 g / 10 min, 190℃ / 2.16 kg.

5. The high-barrier membrane material for chemical protective clothing according to claim 1, characterized in that, The density of the polypropylene random copolymer is 0.90-0.91 g / cm³. 3 The flexural modulus is 850-950 MPa; the density of the metallocene linear low-density polyethylene is 0.912-0.918 g / cm³. 3 The density of the propylene-based elastomer is 0.879-0.902 g / cm³. 3 The density of the ethylene-vinyl alcohol copolymer is 1.10-1.20 g / cm³. 3 .

6. The high-barrier membrane material for chemical protective clothing according to claim 1, characterized in that, The polypropylene random copolymer is RB707CF manufactured by Borealis; the propylene-based elastomer is 3980FL manufactured by ExxonMobil; the maleic anhydride modified polyethylene is NF908 manufactured by Mitsui Chemicals, Inc.; and the ethylene-vinyl alcohol copolymer is ET3203RB manufactured by Kuraray Co., Ltd.

7. The high-barrier membrane material for chemical protective clothing according to claim 6, characterized in that: The polyolefin functional masterbatch mixture consists of two polyolefin functional masterbatches in a mass ratio of 1:

1. One of the polyolefin functional masterbatches is grade 100991-K produced by Anpeise Company, and the other polyolefin functional masterbatch is grade SLP-7 produced by Beijing Yalen Company.

8. A method for preparing a high-barrier membrane material for hazardous chemical protective clothing as described in any one of claims 1-7, characterized in that, The preparation method includes the following steps: S1. The materials of each layer are fed into the barrel of the blown film machine for melt co-extrusion. The temperature of the melt section of the blown film machine is 40-80℃, the temperature of the extrusion section is 190-245℃, the temperature of the die head is 245℃, the extrusion rate is 460-560kg / h, and the blow-up ratio is 1:(1.2-2.5) to form a film bubble and obtain a seven-layer co-extruded blown film. S2. The seven-layer co-extruded blown film is then sequentially traction, cooling, shaping, trimming, and winding to obtain a high-barrier film material.

9. The method for preparing the high-barrier membrane material for chemical protective clothing according to claim 8, characterized in that, After the membrane bubble is cooled and crystallized by internal air circulation at a temperature of 14-25℃, the first traction tension is 100N, the second traction tension is 200N, and the surface center winding clamping force is 200N.

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