Anti-overflow filter element as well as preparation method and application thereof

Abstract

The invention provides an anti-overflow filter element and a preparation method and application thereof. The anti-overflow filter element comprises a shell, a breathable layer, a first sealing layer and a second sealing layer, wherein the breathable layer, the first sealing layer and the second sealing layer are sequentially contained in the shell; the preparation raw material of the first sealing layer is a water absorption swelling agent; the preparation raw materials of the second sealing layer comprise ultra-high molecular weight polyethylene or high-density polyethylene and a water absorption swelling agent; and after sintering, the ultra-high molecular weight polyethylene or high-density polyethylene of the breathable layer and the second sealing layer is integrally connected with the shell. The anti-overflow filter element provided by the invention has a double-layer sealing structure, all areas of the whole first sealing layer absorb water to swell, no cavity exists in the three-dimensional direction, and compared with a traditional expanding agent / polyethylene sealing layer, an outward ventilation channel can be completely blocked and is cooperatively sealed by the second sealing layer, so that the anti-overflow filter element has the advantages that the anti-overflow effect is good; therefore, the anti-overflow filter element is more excellent in gas sealing performance under the condition of negative pressure, and a sample can be prevented from being in contact with outside air.

Description

Technical Field

[0001] The present invention belongs to the technical field of filter element production, and relates to a stop-overflow filter element and a preparation method and application thereof, and in particular to a stop-overflow filter element with a double-layer sealing structure and a preparation method and application thereof. Background Art

[0002] Hospital infection has become an important issue threatening the health of patients and medical staff. Therefore, how to improve the hospital environment has become a key issue. The overflow filter is used to prevent infection and improve the hospital environment. In the hospital environment, since a large number of patients use antibiotic infusions, nurses must exhaust before infusion. The exhaust process often discharges antibiotics directly to the ground. There are a large number of bacteria and other microorganisms in this environment, which lead to the production of drug-resistant strains after long-term contact. The overflow filter is used in the infusion set. By loading the overflow filter on the top of the scalp needle or the infusion set needle protective cover, the gas can pass freely during exhaust. After the exhaust is completed, the injection liquid contacts the filter element, and the filter element is immediately closed to avoid the spillage and diffusion of the injection liquid. The overflow filter is used in blood collection. When used with an arterial blood gas needle, it can prevent the blood from combining with the outside air during blood collection, ensuring the accuracy of blood analysis.

[0003] Medical overflow filter element is made of pure polyethylene (UHMW-PE) and water-absorbing swelling agent as raw materials, and is sintered. The water-absorbing swelling agent fills the micropores between polyethylene particles. When dry, gas can pass freely. In the presence of water, the swelling agent absorbs water and expands, blocking the micropores, and gas and solution cannot pass through (such as Figure 1 shown).

[0004] The existing overflow-stop filter element cannot perfectly fill every pore of the polyolefin powder with the expansion agent, resulting in a through channel in the filter element after water absorption, making the air / liquid sealing performance unable to reach 100%, resulting in liquid leakage or external gas entering and contacting the sample, thus causing adverse effects (such as Figure 2 As shown). Previously, technicians screened polyethylene powder to make the particle size distribution narrower and more compatible with the size of the expansion agent, so as to sinter filter elements with more uniform pore sizes. In addition, some technicians adjusted the pore size and number of different sealing layers to improve the water and gas barrier properties. However, the overflow-stop filter element produced by the above technology cannot achieve a 100% overflow-stop qualified rate in principle only through structural analysis of the filter element.

[0005] Therefore, in the art, it is desired to develop a stop-overflow filter element with good barrier properties. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a spill-proof filter element and a preparation method and application thereof, and in particular to provide a spill-proof filter element with a double-layer sealing structure and a preparation method and application thereof. The spill-proof filter element provided by the present invention has excellent negative pressure sealing performance.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a stop-overflow filter element, the stop-overflow filter element comprising a housing, and a breathable layer, a first sealing layer, and a second sealing layer sequentially contained in the housing;

[0009] The raw material for preparing the first sealing layer is a water-absorbing swelling agent;

[0010] The raw materials for preparing the second sealing layer include uniformly mixed ultra-high molecular weight polyethylene or high-density polyethylene and a water-absorbing swelling agent;

[0011] After sintering, the ultra-high molecular weight polyethylene or high-density polyethylene of the air permeable layer and the second sealing layer are integrally connected with the shell.

[0012] When in use, the air-permeable layer faces inwards, that is, toward the direction of the closed cavity; according to the direction in which the shell is inserted into the mold cavity / or the direction in which the rubber plug is installed, the side facing inwards is the inner side.

[0013] The structure of the overflow-stop filter element provided by the present invention includes at least three layers (such as three layers, four layers, five layers, etc.). In addition to the air permeable layer, the first sealing layer, and the second sealing layer, for example, another air permeable layer can be arranged on the side of the second sealing layer away from the first sealing layer.

[0014] The overflow-stop filter provided by the present invention has a double-layer sealing structure, wherein the water-absorbing swelling agent is used as a separate sealing layer (i.e., the first sealing layer), which can fully absorb water and expand, and there will be no pores between the swelling agent particles, which greatly improves the barrier performance of the overflow-stop filter to liquid / gas. At the same time, when drying, the gaps between the swelling agent particles do not affect the air permeability of the overflow-stop filter; and the second sealing layer also contains part of the water-absorbing swelling agent, which can further improve the barrier performance of the overflow-stop filter to liquid / gas; and after sintering, the ultra-high molecular weight polyethylene or high-density polyethylene of the air-permeable layer and the second sealing layer are integrally connected to the shell, which can prevent the water-absorbing swelling agent from falling off. In addition, the present invention does not need to screen the raw materials, the material utilization rate is higher, and the material and time costs are greatly reduced.

[0015] In the present invention, the air permeable layer is a porous structure, which not only has the air permeability function but also has the function of preventing the water absorption and expansion agent from falling off, and its porosity is sufficient as long as it does not affect the air permeability time.

[0016] Preferably, the thickness of the stop filter element is 4-30mm, for example 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm, 30mm, etc.

[0017] Preferably, the thickness of the air permeable layer is 15%-35% of the thickness of the stop filter element, for example, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35% and the like.

[0018] Preferably, the thickness of the first sealing layer accounts for 20%-40% of the thickness of the stop filter element, for example 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40% and the like.

[0019] Preferably, the thickness of the second sealing layer is 30%-50% of the thickness of the stop filter element, for example 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, etc.

[0020] Preferably, the raw material for preparing the breathable layer is a granular polymer material, for example, it can be any one of granular ultra-high molecular weight polyethylene, high-density polyethylene, polyvinyl chloride, polypropylene, polycarbonate or a combination of at least two thereof, as long as a porous structure can be formed after sintering; preferably, it is granular ultra-high molecular weight polyethylene or high-density polyethylene.

[0021] Preferably, the particle size of the ultra-high molecular weight polyethylene or high-density polyethylene in the breathable layer and the second sealing layer is independently 50-200 microns, for example, 50 microns, 80 microns, 100 microns, 130 microns, 150 microns, 180 microns, 200 microns, etc.

[0022] Preferably, the water-swelling agent in the raw material for preparing the first sealing layer and the water-swelling agent in the raw material for preparing the second sealing layer independently include any one of carboxymethyl cellulose, sodium carboxymethyl starch, and cross-linked sodium polyacrylate, or a combination of at least two thereof. The microstructure of the water-swelling agent is granular, such as a spherical shape, a fiber shape, or the like.

[0023] Preferably, the water-swelling agent in the raw material for preparing the first sealing layer and the water-swelling agent in the raw material for preparing the second sealing layer are of the same type.

[0024] Preferably, based on the total weight of the raw materials for preparing the second sealing layer being 100%, the content of the water-absorbing swelling agent is 10%-30%, for example, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, etc. If the content of the water-absorbing swelling agent is less than 10%, the gaps between the polyethylene particles cannot be completely filled; if the content of the water-absorbing swelling agent is between 30% and 40%, the negative pressure sealing of the overflow-stop filter element is not significantly improved; if the content of the water-absorbing swelling agent is greater than 40%, the water-absorbing swelling agent and polyethylene have no bonding strength under sintering conditions.

[0025] Preferably, the shell is made of polyethylene or polypropylene, which has similar properties to the filter element. Under sintering conditions, the shell, the air permeable layer and the second sealing layer are bonded together to form a whole, solving the problem that the expansion agent cannot be sintered with polyolefin under the sintering conditions.

[0026] Preferably, the shape of the overflow-stop filter element includes a cylindrical shape. It should be noted that the shape of the overflow-stop filter element is not limited to a cylindrical shape, and its specific shape can be determined according to actual needs.

[0027] Preferably, the shell has a certain thickness so that the shell has a certain strength and does not affect the insertion into the mold cavity while ensuring that the air permeable layer and the second sealing layer can be connected and fixed. Preferably, the thickness of the shell is 0.6-0.7 mm, such as 0.6 mm, 0.62 mm, 0.64 mm, 0.65 mm, 0.66 mm, 0.68 mm, 0.7 mm, etc.

[0028] Preferably, the height of the shell is 0.5 mm less than the thickness of the overflow filter element, and one end of the shell is flush with one end of the second sealing layer, and the other end is 0.5 mm lower than one end of the air permeable layer. Figure 5 As shown, the portion of the overflow-stop filter element that is higher than the housing forms a chamfer, and this chamfer is automatically formed by the chamfer on the mold bottom plate. Of course, the overflow-stop filter element provided by the present invention may also have a chamfer or may not have a chamfer.

[0029] In a second aspect, the present invention provides a method for preparing the overflow-stop filter element according to the first aspect, the preparation method comprising the following steps:

[0030] (1) mixing a water-absorbing swelling agent with ultra-high molecular weight polyethylene or high-density polyethylene to obtain a raw material mixture for a second sealing layer;

[0031] (2) placing the shell into the mold cavity, and then adding the raw materials for preparing the air permeable layer, the water absorption expansion agent, and the raw material mixture of the second sealing layer obtained in step (1) into the shell in three steps, and then covering the shell with the template; sintering and molding to obtain the overflow-stopping filter element.

[0032] Preferably, the water-swelling agent in step (1) and step (2) is dried at 50-70°C (e.g., 50°C, 52°C, 54°C, 56°C, 58°C, 60°C, 62°C, 64°C, 66°C, 68°C, 70°C, etc.) for 1-3h, e.g., 1h, 1.2h, 1.4h, 1.6h, 1.8h, 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, etc.) before use.

[0033] Preferably, the shape of the shell in step (2) includes a cylindrical shape with openings at both ends. Of course, the shape of the shell is not limited to a cylindrical shape (that is, the shape of the prepared overflow prevention filter element is not limited to a cylindrical shape), and its shape can be determined according to actual needs. Other shapes can be columns with square or triangular cross-sections, or shapes with a large bottom and a small top; the above shapes only need to be added according to the proportions of each layer described in the present invention, that is, only the layer of pure expansion agent needs to completely cover the interface and have a certain thickness.

[0034] It should be noted that the mold can be in various shapes.

[0035] Preferably, when the shell is placed into the mold cavity in step (2), a spacing of 0.5 mm is maintained between the bottom of the shell and the bottom of the mold cavity, and the mold bottom plate has a chamfer.

[0036] Preferably, in step (2), the raw material for preparing the air permeable layer, the water-absorbing swelling agent, and the raw material mixture of the second sealing layer obtained in step (1) are added into the shell in sequence three times, and the mold is placed on an oscillator and oscillated after each addition, so that the powder particles are in close contact with each other and the flatness between the layers is maintained.

[0037] Preferably, the sintering temperature of the sintering molding in step (2) is 160-170°C, such as 160°C, 162°C, 164°C, 166°C, 168°C, 170°C, etc., and the sintering time is 25-60min, such as 25min, 30min, 35min, 40min, 45min, 50min, 55min, 60min, etc. If the sintering temperature is too high, the powder particles will melt and collapse to block the gaps, and if the sintering temperature is too low, the interfaces of the powder particles will not be able to bond together.

[0038] Preferably, the sintering in step (2) is carried out in an oven.

[0039] Preferably, after the sintering molding in step (2), the step of removing burrs on the surface of the filter element is also included.

[0040] In a third aspect, the present invention provides an application of the anti-overflow filter element as described in the first aspect in a medical device.

[0041] Preferably, the medical device includes a blood gas needle, a drainage bag overflow valve, a urine collection bag filter, a waste liquid collection filter, an infusion filter, etc. In actual use, the filter can be customized according to the shape and size of the medical device to meet the use requirements.

[0042] The following is an introduction to the above applications:

[0043] (1) Disposable drainage bag overflow valve

[0044] Widely used in waste liquid treatment systems in hospitals: disposable drainage bag overflow filter allows air to be discharged freely through the waste liquid collection bag. Once in contact with liquid, the filter will produce a self-sealing effect, effectively preventing liquid from overflowing and preventing liquid from contaminating instruments and the environment.

[0045] (2) Urine bag filter

[0046] Urine collection is an important project in clinical surgery and hospital monitoring. The water-sealed filter element can greatly improve the safety and convenience of the collection bag. During urine collection, the gas in the bag can be discharged through the filter element. When the waste liquid level rises and contacts the water-sealed filter element, the micropores of the filter element are closed, and the waste liquid will not overflow from the waste liquid bag.

[0047] (3) Waste liquid collection filter

[0048] Hospital waste liquid matrix is ​​complex and has certain potential dangers. During the collection process, it is necessary to ensure that no leakage or overflow occurs. When the waste liquid is discharged, the gas can pass freely through the water-sealed filter element without generating negative pressure. When the waste liquid fills the liquid surface and contacts the filter element, it will be sealed immediately to avoid pollution caused by waste liquid overflow, greatly improving the safety of waste liquid collection.

[0049] (4) Infusion filter

[0050] In hospital environments, since a large number of patients use antibiotic infusions, nurses must exhaust air before infusion. During the exhaust process, antibiotics are often discharged directly onto the ground. There are a large number of bacteria and other microorganisms in this environment, which can lead to the production of drug-resistant strains after long-term contact. The water-sealed filter element is installed on the top of the scalp needle or infusion needle protective cover. When exhausting, the gas can pass freely. After the exhaust is completed, the injection liquid contacts the filter element, and the filter element is immediately closed, avoiding the spillage and diffusion of the injection liquid.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] The anti-overflow filter element provided by the present invention has a double-layer sealing structure, wherein the first sealing layer adopts a pure water-absorbing swelling agent, so that all areas of the entire first sealing layer absorb water and expand, and there are no holes in the three-dimensional direction, such as Figure 3 As shown in the figure, compared with the traditional expansion agent / polyethylene sealing layer, the outward air permeable channel can be completely blocked, and the second sealing layer can be used for collaborative sealing, which makes the gas sealing of the overflow filter element even better under negative pressure conditions, and can prevent contact between the sample and the outside air. At the same time, the problem that the pure expansion agent interface and the polyolefin interface cannot be bonded is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is the working principle diagram of the stop-over filter element under ideal conditions.

[0054] Figure 2 This is a diagram showing the actual distribution of the water-absorbing swelling agent in the overflow-stop filter element.

[0055] Figure 3 It is a macroscopic structural diagram of the overflow-stop filter element of the present invention.

[0056] Figure 4 This is a schematic diagram of inserting a housing into a mold according to an embodiment of the present invention.

[0057] Figure 5 A schematic diagram of the structure of the overflow-stop filter element provided in Example 1 of the present invention;

[0058] Among them, 1 is a shell, 2 is a breathable layer, 3 is a first sealing layer, and 4 is a second sealing layer.

[0059] Figure 6 A schematic diagram of the structure of the overflow-stop filter element provided in Comparative Example 4 of the present invention;

[0060] Among them, 1-breathable layer, 2-sealing layer. DETAILED DESCRIPTION

[0061] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0062] Example 1

[0063] In this embodiment, a stop-overflow filter element (cylindrical, 4.7 mm thick) is provided, the stop-overflow filter element comprising a housing and a breathable layer, a first sealing layer, and a second sealing layer sequentially contained in the housing; the material ratio of a single stop-overflow filter element is as follows:

[0064] raw material Raw material type Dosage Ultra-high molecular weight polyethylene (UPE) Main raw materials 8mg Sodium Carboxymethyl Starch(CMS) Main raw materials 8mg CMS / UPE material Main raw materials 8mg Polypropylene housing Main raw materials 4.2mm(Height)

[0065] The preparation method comprises the following steps:

[0066] Step 1: First, dry the CMS in a 60°C oven for 2 hours, prepare a CMS / UPE material with a CMS ratio of 15wt%, and mix it in a crusher for half an hour;

[0067] Step 2: Insert the cylindrical polypropylene shell with openings at both ends into the mold cavity, and keep a 0.5mm gap between the bottom of the shell and the bottom of the mold cavity, and the mold bottom plate has a chamfer (the schematic diagram of the shell being inserted into the mold is shown in Figure 4 shown);

[0068] Step 3: Add UPE (Daehan Petrochemical, U050), CMS (Aladdin, pharmaceutical grade), and CMS / UPE materials into the polypropylene shell in sequence according to the above ratio. Note: After adding each layer, the mold needs to be placed on an oscillator for two minutes to make each layer of powder in close contact and keep the contact surface between the layers flat, so as to ensure that there will be no holes in the filter element;

[0069] Step 4: Place the mold in an oven and sinter at 165°C for 30 minutes. After sintering, cool to room temperature.

[0070] Step 5: Open the mold, take out the filter element, and remove the surface burrs;

[0071] Step 6: Randomly select ten samples to test the air permeability and positive / negative pressure sealing of the filter element. The test method is as follows:

[0072] 1. Breathability (i.e., exhaust properties)

[0073] Inject synthetic blood into the liquid storage container, and remove the air in the pipeline by operating the switch at the end of the pipeline to form a static pressure head of 700mm between the injection seat and the liquid surface of the container. Install the filter into the injection device with a breathable piston, and insert the needle of the injection device into the puncture seat at the end of the pipeline at an angle of about 30° to the horizontal plane. Keep this tilt angle and observe the time it takes for the synthetic blood to flow into the injection device.

[0074] 2. Positive pressure sealing

[0075] 30 seconds after the end of the exhaust test, observe whether the synthetic blood leaks out through the joint between the piston and the pressure rod. Apply 50kPa of air pressure to the synthetic blood storage tank and observe for 30 seconds whether the synthetic blood leaks out through the joint between the injection device pressure rod and the piston.

[0076] 3. Negative pressure sealing

[0077] Push the synthetic blood in the positive pressure sealed injection device to two-thirds of the nominal capacity of the injection device, remove the needle of the injection device, screw on the sealing cap and immerse it face down in an ice water bath for 1 hour, then turn the sealing cap upward, aspirate the air, hold for 15 seconds, and observe whether the gas leaks from the air vent of the piston into the interior of the injection device.

[0078] Among them, the configuration of synthetic blood refers to YY / T 0612-2022, Appendix B.

[0079] The test results are as follows:

[0080]

[0081] Among them, "√" means "qualified", "×" means "unqualified", and the other embodiments and comparative examples have the same meanings and are not repeated here.

[0082] Since the microscopic pore structure of each stop filter element is different, such as the porosity and pore size have small fluctuations, the air permeability time is inconsistent.

[0083] The structural schematic diagram of the overflow-stop filter element provided in Example 1 of the present invention is as follows Figure 5 shown.

[0084] It can be seen that compared with the comparative example 4 described later, the overflow-stop filter element provided in this embodiment has better negative pressure sealing performance, higher uniformity of air permeability time, and smaller fluctuation. This indicates that the filter element provided by the present invention has a higher uniformity of microstructure and still has excellent negative pressure sealing performance after being stored for 12 hours.

[0085] Example 2

[0086] In this embodiment, a stop-overflow filter element (cylindrical, 4.7 mm thick) is provided, the stop-overflow filter element comprising a housing and a breathable layer, a first sealing layer, and a second sealing layer sequentially contained in the housing; the material ratio of a single stop-overflow filter element is as follows:

[0087] raw material Raw material type Dosage Ultra-high molecular weight polyethylene (UPE) Main raw materials 8mg Sodium Carboxymethyl Starch(CMS) Main raw materials 8mg CMS / UPE material Main raw materials 8mg Polypropylene housing Main raw materials 4.2mm(Height)

[0088] Step 1: First, dry the CMS in a 60°C oven for 2 hours, prepare a CMS / UPE material with a CMS ratio of 15wt%, and mix it in a crusher for half an hour;

[0089] Step 2: insert a cylindrical polypropylene shell with openings at both ends into the mold cavity, and keep a distance of 0.5 mm between the bottom of the shell and the bottom of the mold cavity, and the mold bottom plate has a chamfer;

[0090] Step 3: Add UPE (Daehan Petrochemical, U050), CMS (Aladdin, pharmaceutical grade), and CMS / UPE materials into the polypropylene shell in sequence according to the above ratio. Note: After adding each layer, the mold needs to be placed on an oscillator for two minutes to make each layer of powder in close contact and keep the contact surface between the layers flat, so as to ensure that there will be no holes in the filter element;

[0091] Step 4: Place the mold in an oven and sinter at 160°C for 60 minutes. After sintering, cool to room temperature.

[0092] Step 5: Open the mold, take out the filter element, and remove the surface burrs;

[0093] Step 6: Randomly take ten samples to test the air permeability and positive / negative pressure sealing of the filter element (the testing method is the same as that of Example 1).

[0094] The test results are as follows:

[0095]

[0096]

[0097] Example 3

[0098] In this embodiment, a stop-overflow filter element (cylindrical, 4.7 mm thick) is provided, the stop-overflow filter element comprising a housing and a breathable layer, a first sealing layer, and a second sealing layer sequentially contained in the housing; the material ratio of a single stop-overflow filter element is as follows:

[0099] raw material Raw material type Dosage Ultra-high molecular weight polyethylene (UPE) Main raw materials 8mg Sodium Carboxymethyl Starch(CMS) Main raw materials 8mg CMS / UPE material Main raw materials 8mg Polypropylene housing Main raw materials 4.2mm(Height)

[0100] Step 1: First, dry the CMS in a 60°C oven for 2 hours, prepare a CMS / UPE material with a CMS ratio of 15wt%, and mix it in a crusher for half an hour;

[0101] Step 2: insert a cylindrical polypropylene shell with openings at both ends into the mold cavity, and keep a distance of 0.5 mm between the bottom of the shell and the bottom of the mold cavity, and the mold bottom plate has a chamfer;

[0102] Step 3: Add UPE (Daehan Petrochemical, U050), CMS (Aladdin, pharmaceutical grade), and CMS / UPE materials into the polypropylene shell in sequence according to the above ratio. Note: After adding each layer, the mold needs to be placed on an oscillator for two minutes to make each layer of powder in close contact and keep the contact surface between the layers flat, so as to ensure that there will be no holes in the filter element;

[0103] Step 4: Place the mold in an oven and sinter at 170°C for 25 minutes. After sintering, cool to room temperature.

[0104] Step 5: Open the mold, take out the filter element, and remove the surface burrs;

[0105] Step 6: Randomly take ten samples to test the air permeability and positive / negative pressure sealing of the filter element (the testing method is the same as that of Example 1).

[0106] The test results are as follows:

[0107]

[0108] Example 4

[0109] In this embodiment, a stop-overflow filter element (cylindrical, 4.7 mm thick) is provided, the stop-overflow filter element comprising a housing and a breathable layer, a first sealing layer, and a second sealing layer sequentially contained in the housing; the material ratio of a single stop-overflow filter element is as follows:

[0110] raw material Raw material type Dosage Ultra-high molecular weight polyethylene (UPE) Main raw materials 8mg Sodium Carboxymethyl Starch(CMS) Main raw materials 8mg CMS / UPE material Main raw materials 8mg Polypropylene housing Main raw materials 4.2mm(Height)

[0111] Step 1: First, place sodium carboxymethyl starch in a 60°C oven and dry for 2 hours, prepare a CMS / UPE material with a CMS ratio of 30wt%, and mix it in a crusher for half an hour;

[0112] Step 2: insert a cylindrical polypropylene shell with openings at both ends into the mold cavity, and keep a distance of 0.5 mm between the bottom of the shell and the bottom of the mold cavity, and the mold bottom plate has a chamfer;

[0113] Step 3: Add UPE (Daehan Petrochemical, U050), CMS (Aladdin, pharmaceutical grade), and CMS / UPE materials into the polypropylene shell in sequence according to the above ratio. Note: After adding each layer, the mold needs to be placed on an oscillator for two minutes to make each layer of powder in close contact and keep the contact surface between the layers flat, so as to ensure that there will be no holes in the filter element;

[0114] Step 4: Place the mold in an oven and sinter at 165°C for 30 minutes. After sintering, cool to room temperature.

[0115] Step 5: Open the mold, take out the filter element, and remove the surface burrs;

[0116] Step 6: Randomly take ten samples to test the air permeability and positive / negative pressure sealing of the filter element (the testing method is the same as that of Example 1).

[0117] The test results are as follows:

[0118]

[0119] Example 5

[0120] The difference between this embodiment and embodiment 1 is that the material ratio of a single overflow-stop filter element is different, as follows:

[0121] raw material Raw material type Dosage Ultra-high molecular weight polyethylene (UPE) Main raw materials 6mg Sodium Carboxymethyl Starch(CMS) Main raw materials 8mg CMS / UPE material Main raw materials 10mg Polypropylene housing Main raw materials 4.2mm(Height)

[0122] The test results are as follows:

[0123]

[0124]

[0125] Example 6

[0126] The difference between this embodiment and embodiment 1 is that the material ratio of a single overflow-stop filter element is different, as follows:

[0127] raw material Raw material type Dosage Ultra-high molecular weight polyethylene (UPE) Main raw materials 8.4mg Sodium Carboxymethyl Starch(CMS) Main raw materials 6mg CMS / UPE material Main raw materials 9.6mg Polypropylene housing Main raw materials 4.2mm(Height)

[0128] The test results are as follows:

[0129]

[0130] Example 7

[0131] The difference between this embodiment and embodiment 1 is that the material ratio of a single overflow-stop filter element is different, as follows:

[0132] raw material Raw material type Dosage Ultra-high molecular weight polyethylene (UPE) Main raw materials 7.2mg Sodium Carboxymethyl Starch(CMS) Main raw materials 4.8mg CMS / UPE material Main raw materials 12mg Polypropylene housing Main raw materials 4.2mm(Height)

[0133] The test results are as follows:

[0134]

[0135]

[0136] Example 8

[0137] The difference between this embodiment and embodiment 1 is that the material ratio of a single overflow-stop filter element is different, as follows:

[0138] raw material Raw material type Dosage Ultra-high molecular weight polyethylene (UPE) Main raw materials 6.4mg Sodium Carboxymethyl Starch(CMS) Main raw materials 9.6mg CMS / UPE material Main raw materials 8mg Polypropylene housing Main raw materials 4.2mm(Height)

[0139] The test results of the stop filter are as follows:

[0140]

[0141] Example 9

[0142] In this embodiment, a stop-overflow filter element (cylindrical, 4.7 mm thick) is provided, the stop-overflow filter element comprising a housing and a breathable layer, a first sealing layer, and a second sealing layer sequentially contained in the housing; the material ratio of a single stop-overflow filter element is as follows:

[0143]

[0144]

[0145] Step 1: First, place sodium carboxymethyl cellulose in a 60°C oven and dry for 2 hours, prepare CMC / UPE material with a CMC ratio of 15wt%, and mix it in a crusher for half an hour;

[0146] Step 2: insert a cylindrical polypropylene shell with openings at both ends into the mold cavity, and keep a distance of 0.5 mm between the bottom of the shell and the bottom of the mold cavity, and the mold bottom plate has a chamfer;

[0147] Step 3: Add UPE (Daehan Petrochemical, U050), CMC (Aladdin, pharmaceutical grade) and CMC / UPE materials into the polypropylene shell in the above ratio. Note: After adding each layer, the mold needs to be placed on the oscillator for two minutes to make each layer of powder in close contact and keep the contact surface between the layers flat, so as to ensure that there will be no holes in the filter element;

[0148] Step 4: Place the mold in an oven and sinter at 165°C for 30 minutes. After sintering, cool to room temperature.

[0149] Step 5: Open the mold, take out the filter element, and remove the surface burrs;

[0150] Step 6: Randomly take ten samples to test the air permeability and positive / negative pressure sealing of the filter element (the testing method is the same as that of Example 1).

[0151] The test results are as follows:

[0152]

[0153] Example 10

[0154] In this embodiment, a stop-overflow filter element (cylindrical, 4.7 mm thick) is provided, the stop-overflow filter element comprising a housing and a breathable layer, a first sealing layer, and a second sealing layer sequentially contained in the housing; the material ratio of a single stop-overflow filter element is as follows:

[0155] raw material Raw material type Dosage Ultra-high molecular weight polyethylene (UPE) Main raw materials 8mg Cross-linked sodium polyacrylate Main raw materials 8mg Cross-linked sodium polyacrylate / UPE material Main raw materials 8mg Polypropylene housing Main raw materials 4.2mm(Height)

[0156] Step 1: First, place the cross-linked sodium polyacrylate in a 60°C oven and dry for 2 hours, prepare a cross-linked sodium polyacrylate / UPE material with a cross-linked sodium polyacrylate ratio of 15wt%, and mix it in a crusher for half an hour;

[0157] Step 2: insert a cylindrical polypropylene shell with openings at both ends into the mold cavity, and keep a distance of 0.5 mm between the bottom of the shell and the bottom of the mold cavity, and the mold bottom plate has a chamfer;

[0158] Step 3: Add UPE (Daehan Oil Chemical, U050), cross-linked sodium polyacrylate (Aladdin, AR), and cross-linked sodium polyacrylate / UPE materials into the polypropylene shell in sequence according to the above ratio. Note: After adding each layer, the mold needs to be placed on an oscillator and oscillated for two minutes to ensure that each layer of powder is in close contact and the contact surface between the layers remains flat, so as to ensure that there will be no holes in the filter element;

[0159] Step 4: Place the mold in an oven and sinter at 165°C for 30 minutes. After sintering, cool to room temperature.

[0160] Step 5: Open the mold, take out the filter element, and remove the surface burrs;

[0161] Step 6: Randomly take ten samples to test the air permeability and positive / negative pressure sealing of the filter element (the testing method is the same as that of Example 1).

[0162] The test results are as follows:

[0163]

[0164]

[0165] Embodiment 11

[0166] In this embodiment, a stop-overflow filter element (cylindrical, 4.7 mm thick) is provided, the stop-overflow filter element comprising a housing and a breathable layer, a first sealing layer, and a second sealing layer sequentially contained in the housing; the material ratio of a single stop-overflow filter element is as follows:

[0167] raw material Raw material type Dosage Ultra-high molecular weight polyethylene (UPE) Main raw materials 8mg Polyacrylic acid-acrylamide Main raw materials 8mg Polyacrylic acid-acrylamide / UPE material Main raw materials 8mg Polypropylene housing Main raw materials 4.2mm(Height)

[0168] Step 1: First, place the polyacrylic acid-acrylamide in a 60°C oven and dry for 2 hours, prepare a polyacrylic acid-acrylamide / UPE material with a polyacrylic acid-acrylamide ratio of 15wt%, and mix it in a crusher for half an hour;

[0169] Step 2: insert a cylindrical polypropylene shell with openings at both ends into the mold cavity, and keep a distance of 0.5 mm between the bottom of the shell and the bottom of the mold cavity, and the mold bottom plate has a chamfer;

[0170] Step 3: Add UPE (Daehan Petrochemical, U050), polyacrylic acid-acrylamide (Aladdin, AR), and polyacrylic acid-acrylamide / UPE materials into the polypropylene shell in sequence according to the above ratio. Note: After adding each layer, the mold needs to be placed on an oscillator and oscillated for two minutes to make each layer of powder in close contact and keep the contact surface between the layers flat, so as to ensure that there will be no holes in the filter element;

[0171] Step 4: Place the mold in an oven and sinter at 165°C for 30 minutes. After sintering, cool to room temperature.

[0172] Step 5: Open the mold, take out the filter element, and remove the surface burrs;

[0173] Step 6: Randomly take ten samples to test the air permeability and positive / negative pressure sealing of the filter element (the testing method is the same as that of Example 1).

[0174] The test results are as follows:

[0175]

[0176]

[0177] Example 12

[0178] The difference between this embodiment and embodiment 1 is that the material ratio of a single overflow-stop filter element is different, as follows:

[0179] raw material Raw material type Dosage Ultra-high molecular weight polyethylene (UPE) Main raw materials 12.4mg Sodium Carboxymethyl Starch(CMS) Main raw materials 3.6mg CMS / UPE material Main raw materials 8mg Polypropylene housing Main raw materials 4.2mm(Height)

[0180] The test results of the stop filter are as follows:

[0181]

[0182] Example 13

[0183] The difference between this embodiment and embodiment 1 is that the material ratio of a single overflow-stop filter element is different, as follows:

[0184]

[0185]

[0186] The test results of the stop filter are as follows:

[0187]

[0188] The filter element provided in this embodiment has a first sealing layer that is too thick and a relatively thin air permeable layer. After the filter element absorbs water and is stored for a long time, the expansion force of the expansion agent in the first sealing layer may push open the air permeable layer. Continuous water absorption may cause leakage of the expansion agent, ultimately rendering the negative pressure seal ineffective.

[0189] Comparative Example 1

[0190] The only difference between this comparative example and Example 1 is that the CMS / UPE material is replaced by an equal amount of pure UPE material, that is, the second sealing layer does not contain a water-absorbing swelling agent.

[0191] The test results of the stop filter are as follows:

[0192]

[0193]

[0194] Comparative Example 2

[0195] The only difference between this comparative example and Example 1 is that the overflow-stop filter element does not contain a first sealing layer.

[0196] The test results of the stop filter are as follows:

[0197]

[0198] Comparative Example 3

[0199] The difference between this comparative example and Example 1 is that in step three of the preparation method, UPE (Korea Petrochemical, U050), CMS / UPE material, and CMS (Aladdin, pharmaceutical grade) are added to the polypropylene shell in sequence, that is, the order of the first sealing layer and the second sealing layer in Example 1 is exchanged.

[0200] The test results of the stop filter are as follows:

[0201]

[0202] It can be seen from the above embodiments and comparative examples that the overflow-stop filter element provided by the embodiments of the present invention has excellent negative pressure sealing performance.

[0203] Comparative Example 4

[0204] In this comparative example, a stop-flow filter element (cylindrical, 4.7 mm thick) is provided, and its structural schematic diagram is shown as follows: Figure 6 As shown, the overflow-stop filter element includes a breathable layer 1 and a sealing layer 2; the material ratio of a single overflow-stop filter element is as follows:

[0205] raw material Raw material type Dosage Ultra-high molecular weight polyethylene (UPE) Main raw materials 12mg CMS / UPE material Main raw materials 12mg

[0206] The preparation method comprises the following steps:

[0207] Step 1: First, CMS (Aladdin, pharmaceutical grade) was placed in a 60°C oven and dried for 2 hours, and a CMS / UPE material with a CMS ratio of 15 wt% was prepared and mixed in a crusher for half an hour;

[0208] Step 2: Add UPE (Daehan Oil Chemical, U050) into the mold cavity according to the above ratio and shake it to make the particles closely contact with each other and the surface is flat. Then add CMS / UPE material and shake it again to make the particles closely contact with each other and the surface is flat.

[0209] Step 3: Place the mold in an oven and sinter at 165°C for 30 minutes. After sintering, cool to room temperature.

[0210] Step 4: Open the mold, take out the filter element, and remove the surface burrs;

[0211] Step 5: Randomly take ten samples to test the air permeability and positive / negative pressure sealing of the filter element (the testing method is the same as that of Example 1).

[0212] The test results are as follows:

[0213]

[0214]

[0215] The applicant declares that the present invention illustrates the anti-overflow filter element and its preparation method and application through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A overflow-stop filter element, characterized in that: The overflow-stop filter element comprises a shell, and a breathable layer, a first sealing layer, and a second sealing layer sequentially contained in the shell; The raw material for preparing the first sealing layer is a water-absorbing swelling agent; The raw materials for preparing the second sealing layer include ultra-high molecular weight polyethylene or high-density polyethylene, and a water-absorbing swelling agent; After sintering, the ultra-high molecular weight polyethylene or high-density polyethylene of the air permeable layer and the second sealing layer are integrally connected with the shell.

2. The overflow-stop filter element according to claim 1, characterized in that: The thickness of the overflow-stop filter element is 4-30 mm; Preferably, the thickness of the air permeable layer accounts for 15%-35% of the thickness of the overflow-stop filter element; Preferably, the thickness of the first sealing layer accounts for 20%-40% of the thickness of the overflow-stop filter element; Preferably, the thickness of the second sealing layer accounts for 30%-50% of the thickness of the overflow-stop filter element.

3. The overflow-stop filter element according to claim 1 or 2, characterized in that: The raw material for preparing the air permeable layer is a granular polymer material; Preferably, the granular polymer material includes any one of granular ultra-high molecular weight polyethylene, high-density polyethylene, polyvinyl chloride, polypropylene, and polycarbonate, or a combination of at least two thereof, preferably granular ultra-high molecular weight polyethylene or high-density polyethylene; Preferably, the particle sizes of the ultra-high molecular weight polyethylene or high-density polyethylene in the breathable layer and the second sealing layer are independently 50-200 microns.

4. The overflow-stop filter element according to any one of claims 1 to 3, characterized in that: The water-swelling agent in the raw material for preparing the first sealing layer and the water-swelling agent in the raw material for preparing the second sealing layer independently include any one of carboxymethyl cellulose, sodium carboxymethyl starch, and cross-linked sodium polyacrylate, or a combination of at least two thereof; Preferably, the water-swelling agent in the raw material for preparing the first sealing layer and the water-swelling agent in the raw material for preparing the second sealing layer are of the same type.

5. The overflow-stop filter element according to any one of claims 1 to 4, characterized in that: Based on the total weight of the raw materials for preparing the second sealing layer being 100%, the content of the water-absorbing swelling agent is 10%-30%.

6. The overflow-stop filter element according to any one of claims 1 to 5, characterized in that: The shell is made of polyethylene or polypropylene.

7. The overflow-stop filter element according to any one of claims 1 to 6, characterized in that: The shape of the overflow-stop filter element includes a cylindrical shape; Preferably, the thickness of the shell is 0.6-0.7 mm; Preferably, the height of the shell is 0.5 mm smaller than the thickness of the overflow-stop filter element, and one end of the shell is flush with one end of the second sealing layer, and the other end is 0.5 mm lower than one end of the air-permeable layer.

8. A method for preparing a spill-proof filter element as claimed in any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: (1) mixing a water-absorbing swelling agent with ultra-high molecular weight polyethylene or high-density polyethylene to obtain a raw material mixture for a second sealing layer; (2) placing the shell into the mold cavity, and then adding the raw materials for preparing the air permeable layer, the water absorption expansion agent, and the raw material mixture of the second sealing layer obtained in step (1) into the shell in three steps; sintering and molding to obtain the overflow-stopping filter element.

9. The preparation method according to claim 8, characterized in that: The water-swelling agent in step (1) and step (2) is dried at 50-70° C. for 1-3 h before use; Preferably, the shape of the shell in step (2) includes a cylindrical shape with openings at both ends; Preferably, when the shell is placed in the mold cavity in step (2), a gap of 0.5 mm is maintained between the bottom of the shell and the bottom of the mold cavity, and the mold bottom plate has a chamfer; Preferably, in step (2), the raw material for preparing the air permeable layer, the water-absorbing swelling agent, and the raw material mixture of the second sealing layer obtained in step (1) are added to the shell in sequence three times, and after each addition, the mold is placed on an oscillator and oscillated to ensure that the powder particles are in close contact with each other and the flatness between the layers is maintained; Preferably, the sintering temperature of the sintering molding in step (2) is 160-170° C., and the sintering time is 25-60 min; Preferably, the sintering in step (2) is carried out in an oven; Preferably, after the sintering molding in step (2), the step of removing burrs on the surface of the filter element is also included.

10. Use of the overflow-stop filter element according to any one of claims 1 to 7 in medical devices; Preferably, the medical device includes a blood gas needle, a drainage bag overflow valve, a urine collection bag filter element, a waste liquid collection filter element, and an infusion set filter element.

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