DE102012010307A1 - Multilayer filter material of filter element for liquid filtration, has main portion that is provided with pre-filter layer, main filter layer and absolute hydrophilic or hydrophobic filter layer - Google Patents

Multilayer filter material of filter element for liquid filtration, has main portion that is provided with pre-filter layer, main filter layer and absolute hydrophilic or hydrophobic filter layer

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Publication number
DE102012010307A1
DE102012010307A1 DE201210010307 DE102012010307A DE102012010307A1 DE 102012010307 A1 DE102012010307 A1 DE 102012010307A1 DE 201210010307 DE201210010307 DE 201210010307 DE 102012010307 A DE102012010307 A DE 102012010307A DE 102012010307 A1 DE102012010307 A1 DE 102012010307A1
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DE
Germany
Prior art keywords
layer
filter material
filter
mm
material according
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
DE201210010307
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German (de)
Inventor
Andreas Demmel
Christoph Häringer
Christof Keppler
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Neenah Gessner GmbH
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Neenah Gessner GmbH
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Filing date
Publication date
Application filed by Neenah Gessner GmbH filed Critical Neenah Gessner GmbH
Priority to DE201210010307 priority Critical patent/DE102012010307A1/en
Publication of DE102012010307A1 publication Critical patent/DE102012010307A1/en
Application status is Pending legal-status Critical

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D39/00Filtering material for liquid or gaseous fluids
    • B01D39/14Other self-supporting filtering material ; Other filtering material
    • B01D39/20Other self-supporting filtering material ; Other filtering material of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D39/00Filtering material for liquid or gaseous fluids
    • B01D39/14Other self-supporting filtering material ; Other filtering material
    • B01D39/16Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D39/00Filtering material for liquid or gaseous fluids
    • B01D39/14Other self-supporting filtering material ; Other filtering material
    • B01D39/16Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
    • B01D39/18Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being cellulose or derivatives thereof
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2239/00Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/04Additives and treatments of the filtering material
    • B01D2239/0414Surface modifiers, e.g. comprising ion exchange groups
    • B01D2239/0421Rendering the filter material hydrophilic
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2239/00Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/04Additives and treatments of the filtering material
    • B01D2239/0414Surface modifiers, e.g. comprising ion exchange groups
    • B01D2239/0428Rendering the filter material hydrophobic
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2239/00Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/06Filter cloth, e.g. knitted, woven non-woven; self-supported material
    • B01D2239/0604Arrangement of the fibres in the filtering material
    • B01D2239/0618Non-woven
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2239/00Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/06Filter cloth, e.g. knitted, woven non-woven; self-supported material
    • B01D2239/0604Arrangement of the fibres in the filtering material
    • B01D2239/0622Melt-blown
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2239/00Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/06Filter cloth, e.g. knitted, woven non-woven; self-supported material
    • B01D2239/065More than one layer present in the filtering material
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2239/00Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/06Filter cloth, e.g. knitted, woven non-woven; self-supported material
    • B01D2239/065More than one layer present in the filtering material
    • B01D2239/0654Support layers

Abstract

A multilayer filter material for liquid filtration has at least one prefilter layer, at least one main filter layer and at least one absolute filter layer, wherein a prefilter layer comprises a wet-laid or dry-laid nonwoven in the direction of flow, the main filter layer is a wet-laid nonwoven made of cellulose or synthetic fibers or inorganic fibers or a mixture thereof and the absolute filter layer comprises a calendered meltblown web.

Description

  • The invention relates to multilayer filter materials for the separation of coarse and fine contaminants from liquid streams and filter elements made therefrom.
  • Previous state of the art
  • In many areas of filtration, the requirements for the degree of purity of filtered liquids increase. This applies both to industrially used fluids such as lubricating oils, hydraulic oils or fuels for internal combustion engines, as well as for liquids in the food industry and for medical or pharmaceutical applications. For example, in the filtration of diesel fuels for internal combustion engines, the requirement for the degree of separation increased ISO 19438 for 4 μm particles in the last 15 years from 50% to 96% and will be over 99% in the future. Therefore, great efforts have been made in the past to continuously increase the degree of separation of the filter materials used while maintaining the dust storage capacity and thus the life of the filter at least unchanged. Meanwhile, it is no longer enough that the filter material used fulfills the required degree of separation for coarse and fine particles. Due to the high purity requirements, the particle discharge of many filter materials themselves is becoming increasingly important.
  • Depending on the nature and manufacturing process, all filter materials contain contaminants that are loosely distributed throughout the filter material. If a fluid now flows through the filter material, these impurities are released and enter the fluid. The fluid is thus contaminated by the filter material itself. This property is called particle delivery. It is not to be confused with the penetration of already filtered-out dirt particles due to an insufficient retention capacity or an overload of the filter material. Particles in the sense of the term particle delivery can be both fiber fragments which are produced during the production and further processing of filter materials, or also genuine particles, such as, for example, dust, sand or resin particles. For example, in the production of filter paper, small grains of sand enter the paper through the process water or the pulp used. Fiber fragments and fiber dust are produced by grinding the pulp. Subsequent impregnation of the paper produces resin particles. All these impurities are loose in the filter paper and are easily discharged through the fluid to be filtered. Glass fibers are very brittle and break easily under mechanical stress in more or less small pieces, which are then also loose in the filter material. Even soft filter materials, such as meltblown nonwovens, include loosely adhering contaminants, such as ruptured fibers, polymer particles or dust particles, which are attracted to the environment by the natural electrostatic charge of these nonwoven webs.
  • During further processing to the filter element, further particles are produced, for example, by folding. Even during the filtration process, abrasive particles or hydrostatic pressure can cause the formation of particles, which then enter the filtered fluid.
  • In this case, a distinction must be made between an initial particle delivery and a permanent particle delivery. At the initial particle delivery after VDA Volume 19 During the first flushing of a newly inserted filter, the particles which have been or were introduced during the entire production process of the filter material are discharged with the liquid to be filtered. In the permanent release of particles by abrasion and hydrostatic pressure newly formed or solid embedded particles are released.
  • When assessing the release of particles not only the amount of particles released plays a role, but also their size and hardness. The larger and harder a particle is, the more damage it will do to subsequent aggregates, such as pumps and nozzles.
  • Although the amount of such particles that are discharged from the filter materials in the purified liquid stream, although relatively small, but often exceeds the amount of unfiltered dirt from the contaminated liquid.
  • Today, a large number of highly selective filter materials are already on the market. In the field of filtration of hydraulic and lubricating oils glass fiber-containing filter papers are often used, as for example in the patent application DE 4440432 A1 are described. Unfortunately, glass fibers are very brittle. Both during manufacture and during further processing, individual fibers break up into small fragments, which then cause the high particle output of these filter materials. Because the Glass fiber fragments are very hard and abrasive, they often cause great damage, for example in subsequent pumps or nozzles.
  • Therefore, some efforts have been made to prevent the particle discharge of the glass fiber-containing filter media. The registration letter WO 2002060559 A2 describes a filter medium for the liquid filtration, which consists of a glass fiber fleece as a filter layer. On the clean side of the glass fiber fleece is a non-fiberglass nonwoven, which is to retain glass fiber fragments. A paper on the dirty side of the glass fiber fleece gives the composite the necessary strength and rigidity. On the used non-fiberglass nonwoven, however, will not be discussed in detail. Therefore, it can be assumed that fiber fragments are also released into the cleaned liquid from this fleece. Although the fiber fragments of the nonwoven are softer than glass fiber fragments and thus significantly less abrasive, but nevertheless contribute to the fact that the purity requirements of the purified liquid are not met. In addition, the teaching can not be seen whether really all glass fiber fragments are retained.
  • The Utility Model DE 20 2007 013 215 U1 also describes a glass fiber filter material followed by a non-woven on the clean side. This is a meltblown fleece. A special treatment of Meltblownvlieses, z. B. by compaction or impregnation is not described. Although such meltblown nonwovens are able, depending on the nature, to retain the glass fiber fragments to a certain extent, they can not completely avoid the delivery.
  • Despite the fact that, despite these innovations, a discharge of glass fiber fragments into the already cleaned liquid can not be reliably avoided, it was attempted to achieve the good filter properties of glass fiber-containing filter materials by means of glass fiber-free filter composites.
  • The publication DE 197 52 143 A1 describes a filter material for the liquid filtration, which has an increasing separation efficiency and a decreasing storage capacity in the direction of flow. On the clean side is a predominantly cellulose-containing paper. In this case, glass or synthetic fibers may also be added to the downstream, predominantly cellulosic filter paper. In addition, it can have an impregnation. The highest degree of separation reaches the described filter material in a preferred embodiment by a calendered meltblown layer between the prefilter layer and the downstream filter paper. The filter paper on the clean side, however, causes a large amount of particles is discharged into the filtered liquid and the purity required for the liquid is not achieved, despite the high degree of separation.
  • In the patent EP 1 133 342 B1 a filter material is described, which consists of a prefilter layer, a main filter layer and a clean-side, mainly cellulosic support layer builds. The main filter layer preferably consists of a glass fiber fleece or a calendered meltblown fleece. Even if the predominantly cellulose-containing support layer has sufficient filter properties to retain glass fiber fragments from the main filter layer, it nevertheless contaminates the filtered liquid even by dispensing many particles. Even with this filter material, the required high degree of purity of the liquid therefore can not be achieved.
  • Another glass fiber-free filter material is known from the published patent application DE 10 2009 006 583 A1 seen. On the inflow side there is a wet-laid fleece, followed by a meltblown fleece and a spunbonded nonwoven as a protective layer for the meltblown fleece. The wet-laid nonwoven serves as a prefilter, while the meltblown nonwoven represents the main filtration layer. Practice has shown that the embodiment of the laid open in the publication DE 10 2009 006 583 A1 described prefilter and main filter layer is not able to achieve the required high separation efficiencies in the filtration of liquids. In addition, a large number of particles from the filter material is also discharged into the cleaned liquid here. These particles originate from both the wet-laid and impregnated nonwoven as well as from the meltblown layer itself.
  • In the filtration of liquids in the food, medicine and pharmaceutical industry today increasingly uses membrane-containing filter materials. Such filter materials are exemplary in the patent specification US 4,244,820 A described. Membranes have an extremely high degree of separation and a very low particle discharge. With membranes therefore very clean liquids can be produced. Since membranes must have very small pores to achieve their excellent cleaning effect, they also clog very quickly. In addition, the flow rate through membranes is very low. Membrane-containing filter materials are therefore only suitable if the contaminated liquid has already been removed by prefilter, the largest part of the dirt particles and if the low flow rate can be accepted or compensated by increasing the filter area.
  • Object of the present invention is therefore to provide a filter material for liquids, which has a very high degree of separation for coarse and fine dirt particles at the same high flow rate and low tendency to clog and in addition has a low particle delivery.
  • Summary of the invention
  • The object is achieved by a three-layer filter material, wherein each layer comprises one or more layers. The first layer comprises, as viewed in the direction of flow, a wet or dry laid web as prefilter material, the second layer comprises a wet laid web of cellulose or synthetic fibers or inorganic fibers or a mixture thereof as the main filter material, and the third layer comprises a calendered meltblown web.
  • Detailed description of the invention
  • The filter material according to the invention has a basis weight of 50 g / m 2 -800 g / m 2 , preferably of 200 g / m 2 -600 g / m 2 , a thickness of 0.3 mm-6.0 mm, preferably of 0, 5 mm-3.0 mm, an air permeability of 1 l / m 2 s-50 l / m 2 s, preferably from 3 l / m 2 s-10 l / m 2 s, a dust storage capacity after ISO 4020 of at least 300 s, preferably of at least 400 s, an initial separation efficiency for 4 μm particles after ISO 19438 of at least 90%, preferably of at least 96%, more preferably of at least 98%, a dust holding capacity according to ISO 19438 of at least 1.5 g, preferably of 2.0 g, a particle delivery after VDA Volume 19 of at most 1500 particles of size 5 μm-15 μm, preferably of at most 1400 particles of size 5 μm-15 μm, of at most 450 particles of size 15 μm-25 μm, preferably at most 400 particles of size 15 μm-25 μm, at most 300 particles of the size 25 μm-50 μm, preferably at most 280 particles of the size 25 μm-50 μm and an increase of the water separation according to ISO 16332 , compared to the same filter material but without absolute filter layer, of at least 10% points, preferably of at least 15% points. According to ISO 16332, water separation is expressed as a percentage of the total water content in the fuel,% points are the absolute increase, for example, an increase from 80% water separation to 90% water separation results in an increase of 10% points.
  • The first layer of the filter material according to the invention, as seen in the direction of flow, comprises a wet-laid or dry-laid nonwoven. This fleece serves as a dust reservoir for the majority of the coarse impurities. As a result, it has a more open structure and thus a higher porosity compared to the subsequent main filter material. The pre-filter has a basis weight of 10 g / m 2 -350 g / m 2 , preferably from 20 g / m 2 -250 g / m 2 , an air permeability of 50 l / m 2 s-2000 l / m 2 s, preferably of 100 l / m 2 s-1000 l / m 2 s, a thickness of 0.05 mm-4.0 mm, preferably of 0.2 mm-2.0 mm, and a porosity of 60% -97%, preferably from 65% -96%. Suitable pre-filter material are all nonwovens known in the art, such as, for example, meltblown nonwovens, spunbonded nonwovens, dry laid staple fiber webs, dry or wet laid glass fiber webs or paper. Depending on requirements, the person skilled in the art selects the most suitable material for the prefilter layer. The first layer can consist exclusively of a wet or dry laid nonwoven. Furthermore, it is also possible to combine different materials, such as. B. a meltblown layer followed by a paper layer. In this combination, the meltblown layer preferably has a higher dust storage capacity and a lower degree of separation than the subsequent paper layer.
  • In a preferred embodiment, the prefilter layer is a meltblown web having a basis weight of 30 g / m 2 -200 g / m 2 , a thickness of 0.1 mm-0.8 mm, an air permeability of 50 l / m 2 s-1000 l / m 2 s and a porosity of 65% -90%.
  • In a further preferred embodiment, the prefilter layer is a wet-laid nonwoven in the form of a filter paper consisting of 10-90% by weight cellulose and 10-90% by weight polyester fiber having a linear density of 0.3 dtex-8.0 dtex and 3 mm 12 mm cutting length. It has an impregnating agent content of 5% by weight - 40% by weight, a basis weight of 20 g / m 2 - 250 g / m 2 , a thickness of 0.1 mm - 2.0 mm, an air permeability of 150 l / m 2 s-2000 l / m 2 s and a porosity of 65-95%.
  • In a further preferred embodiment, the prefilter layer consists of a combination of a meltblown nonwoven and a filter paper, wherein the meltblown nonwoven represents the first layer seen in the flow direction. This meltblown nonwoven has a basis weight of 30 g / m 2 to 200 g / m 2 , a thickness of 0.1 mm-0.8 mm, an air permeability of 50 l / m 2 s-1000 l / m 2 s and a porosity from 65% -90%. The filter paper consists of 10% by weight - 90% by weight cellulose and 10% by weight - 90% by weight polyester fiber with a linear density of 0.3 dtex-8.0 dtex and 3 mm-12 mm cutting length. It has a impregnating agent content of 5-40 % By weight, a basis weight of 20 g / m 2 -250 g / m 2 , a thickness of 0.1 mm-2.0 mm, an air permeability of 150 l / m 2 s-2000 l / m 2 s and a porosity from 65% -95%.
  • The main filter layer of the filter material according to the invention is always formed by a paper. Depending on the requirements and application, papers made of 100% cellulose, 100% synthetic fibers, 100% inorganic fibers or mixtures thereof are used. The main filter layer can be impregnated, wherein the type of impregnating agent is selected by the skilled person depending on the intended use of the filter material according to the invention. The proportion of the dry impregnating agent in the total weight of the paper is typically 0.5% by weight - 50% by weight, preferably 5% by weight - 40% by weight. The main filter layer typically has a basis weight of 50 g / m 2 -300 g / m 2 , preferably of 150 g / m 2 -250 g / m 2 , a thickness of 0.2 mm-2.0 mm, preferably of 0, 4 mm-0.8 mm, an air permeability of 2 l / m 2 s-50 l / m 2 s, preferably of 5 l / m 2 s-20 l / m 2 s and a porosity of 65% -95%, preferably from 65% to 90%.
  • In a preferred embodiment, the main filter layer is a paper consisting of 100% by weight of cellulose. It has an impregnating agent content of 5-40 wt.%, A basis weight of 150 g / m 2 -250 g / m 2 , a thickness of 0.4 mm-0.8 mm, an air permeability of 5 l / m 2 s- 20 l / m 2 s and a porosity of 70% -80%.
  • In a further preferred embodiment, the main filter layer is a paper consisting of 10% by weight - 90% by weight cellulose and 10% by weight - 90% by weight synthetic fiber having a linear density of 0.3 dtex-8.0 dtex and 3 mm-12 mm cutting length. It has an impregnating agent content of 5-40 wt.%, A basis weight of 150 g / m 2 -250 g / m 2 , a thickness of 0.4 mm-0.8 mm, an air permeability of 5 l / m 2 s- 20 l / m 2 s and a porosity of 70% -80%.
  • In a further preferred embodiment, the main filter layer is a paper consisting of 0 wt.% - 97 wt% cellulose and 3 wt.% - 100 wt.% Glass fiber having a mean fiber diameter of 0.0002 mm-5.0 mm. It has an impregnating agent content of 0-25 wt.%, A basis weight of 150 g / m 2 -250 g / m 2 , a thickness of 0.4 mm-0.8 mm, an air permeability of 5 l / m 2 s- 20 l / m 2 s and a porosity of 80% -90%.
  • The third filter system or absolute filter layer comprises a calendered meltblown web. The absolute filter layer preferably consists exclusively of such a meltblown web. The nonwoven produced in the meltblown process is compressed between two calender rolls, which are hot at 10 ° C. to 180 ° C., with a line pressure of 50 N / mm to 450 N / mm. By calendering the individual fibers and fiber fragments are thermally bonded to each other and thus no longer contribute to the release of particles. At the same time, the calendering reduces the porosity of the meltblown web. This has the consequence that the separation efficiency of the filter material according to the invention increases significantly. In a preferred embodiment, the porosity of the absolute filter layer after calendering is equal to or less than that of the main filter layer.
  • If one uses the filter material according to the invention for the purification of a liquid mixture of two immiscible liquids, the absolute filter layer can allow the passage of the continuous phase and retain the disperse phase if the choice of material is correct. An example of this is the separation of water from fuels. The water is the disperse and the fuel is the continuous phase. By using hydrophobic polymers, such as polybutylene terephthalate, to make the meltblown web, it is possible to collect and separate water droplets formed on a suitable upstream coalescer medium on the calendered meltblown layer as the anhydrous fuel passes unhindered through the absolute filter layer ,
  • The polymer used for the preparation of the calendered meltblown web can additionally be adapted to the separation task by additives, for example fluorohydrocarbons or waxy substances. The surface property of the calendered meltblown web can also be affected by surface treatment methods such as corona treatment or plasma treatment.
  • The absolute filter layer of a calendered meltblown web typically has a basis weight of 20 g / m 2 -300 g / m 2 , preferably of 30 g / m 2 -200 g / m 2 , a thickness of 0.02 mm-0.5 mm, preferably from 0.03 mm-0.4 mm, an air permeability of 1 l / m 2 s-200 l / m 2 s, preferably from 2 l / m 2 -100 l / m 2 and a porosity of 10-60% , preferably from 20-55%.
  • There now follow some possible embodiments of the filter material according to the invention. This list is intended only to illustrate the present invention and does not include all possible Embodiments. The invention is therefore not limited to the specified embodiments. In the context of the invention, it is readily possible that at least one of the first, second and third layers consists of several layers or layers. Furthermore, it is also possible that one or more further layers of other materials are present between the first and second layers and / or the second and third layers, if these do not or at least substantially do not affect the filtration performance. Furthermore, it is also possible for one or more layers of other materials to be provided before the first layer and / or after the third layer, if this does not or at least not substantially affect the filtration performance. prefilter: meltblown Main filter Location: paper Absolute filters Location: calendered meltblown prefilter: spunbond Main filter Location: paper Absolute filters Location: calendered meltblown fleece prefilter: drained staple fiber fleece Main filter Location: paper Absolute filters Location: calendered meltblown fleece 1. Prefilter layer: meltblown 2. Prefilter layer: paper Main filter Location: paper Absolute filters Location: calendered meltblown fleece prefilter: meltblown 1. Main filter layer: paper 2. Main filter layer: paper Absolute filters Location: calendered meltblown fleece prefilter: meltblown Main filter Location: paper 1. Absolute filter layer: calendered meltblown fleece 2. Absolute filter layer: calendered meltblown fleece 1. Prefilter layer: meltblown 2. Prefilter layer: paper 1. Main filter layer: paper 2. Main filter layer: paper 3. Main filter layer: paper 1. Absolute filter layer: calendered meltblown fleece 2. Absolute filter layer: calendered meltblown fleece
  • The individual layers of the filter material according to the invention are connected either with an adhesive or via welded joints or a combination thereof.
  • Advantageous adhesives have a softening point of over 200 ° C. When used as intended, the filter material of the invention is exposed to temperatures up to 150 ° C and high hydrostatic pressures. The adhesive connection must not come loose. Suitable adhesives for this application are polyurethane adhesive, polyamide adhesive or polyester adhesive. Particularly preferred are polyurethane adhesives that crosslink with the humidity. The adhesives can be applied either as a powder or melted by means of anilox rolls or spray nozzles. The application weight of the adhesive is typically between 5-20 g / m 2 , preferably between 5-10 g / m 2 .
  • The welded connection can be made both by an ultrasonic system and by a thermal calender. The polymers of the layers to be welded are either completely or partially melted and welded together. In this case, the area-wise welded joints can have any geometric shapes, such as points, straight lines, curved lines, diamonds, triangles, etc. The area of the area-wise welded joints is advantageously at most 10% of the total area of the filter material according to the invention.
  • Gluing and welding can also be combined with each other.
  • If the main filter layer consists of several layers, then the individual layers can already be brought together in a paper machine known to the experts with a suitable headbox. An additional connection of the individual layers, for example by gluing, is then no longer necessary.
  • Definitions and methods of measurement
  • Dry laid staple fiber fleece
  • Dry laid staple fiber webs consist of fibers of finite length. Both natural and synthetic fibers can be used to produce dry laid staple fiber webs. Examples of natural fibers are cellulose, wool, cotton, flax. Synthetic fibers are, for example, polyolefin fibers, polyester fibers, polyamide fibers, polytetrafluoroethylene fibers, polyphenylene sulfide fibers. The fibers used can either be straight or crimped. For solidification, the air-laid staple fiber fleece can contain one-component or multi-component meltbond fibers which melt completely or partially at a temperature below the melting temperature of the other fibers and solidify the fleece. The preparation of the air-laid Stapelfaservliese done according to the prior art as in the book "Nonwovens, W. Albrecht, H. Fuchs, W. Kittelmann, Wiley-VCH, 2000 , described. The dried Stapelfaservliese can be solidified by the aforementioned one- or multi-component meltbonding fibers.
  • Other solidification options are, for example, needling, water jet needling or soaking or spraying the fleece with liquid binders followed by drying. A dry-laid staple fiber nonwoven suitable for the filter material according to the invention is, for example, FFV 43381 from Fulda GmbH & Co KG, Fulda.
  • meltblown
  • Meltblown nonwovens consist of polymeric continuous fibers. To produce the meltblown nonwoven fabric for the filter material according to the invention, the meltblown process known in the art is used, as described, for example, in US Pat. In Van A. Wente, "Superfine Thermoplastic Fibers", Industrial Engineering Chemistry, Vol. 48, pp. 1342-1346 is described. Suitable polymers are, for example, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyamide, polyphenylene sulfide, polyolefin. The typical fiber diameter range between 0.5-10 μm, preferably between 0.5-3 μm. Depending on the requirements, additives such as, for example, hydrophilicizing agents, hydrophobizing agents, crystallization accelerators or paints can also be added to the polymers. Depending on requirements, the surface of the meltblown nonwoven can be changed in its property by surface treatment methods, such as corona treatment or plasma treatment.
  • spunbondeds
  • Spunbonded nonwovens are also made of polymeric filaments whose fiber diameter is usually much larger than that of meltblown fibers. Spun nonwovens are produced by the spunbonding process known to the experts. In this case, a thermoplastic polymer is melted in an extruder and pushed through a spinneret. The continuous fibers formed in the capillaries of the spinneret are drawn out of the nozzle after exiting, swirled in a storage channel and laid down in a web on a wire belt. Subsequently, the fleece is either needled or solidified with an embossing calender using pressure and temperature. Suitable polymers are, for. As polyethylene terephthalate, Polybutylentherephtalat, Polyethylennaphtalat, Polybutylennaphtalat, polyamide, polyphenylene sulfide, polyolefin or multi-component fibers.
  • Wet-laid nonwovens
  • Wet-laid nonwovens or papers in the sense of this invention are all nonwovens which can be produced with the wet-laying processes known in the art for the production of filter papers. The papers for the filter material according to the invention consist of natural, synthetic, inorganic fibers or a mixture thereof. Examples of natural fibers are cellulose, cotton, wool, hemp, wherein the cellulosic material used may be wood-free and / or wood-containing celluloses of coniferous and / or deciduous trees, regenerated celluloses and fibrillated celluloses. Inorganic fibers are, for example, glass fiber, carbon fibers, basalt fibers, quartz fibers and metal fibers. Suitable synthetic fibers are, for example, polyester fibers, polypropylene fibers, multi-component fibers with different melting points of the individual components, polyamide fibers and polyacrylonitrile fibers. The denier of the synthetic fibers is typically 0.1 dtex-10.0 dtex, preferably 0.3 dtex-8.0 dtex, and the cut length is typically 3 mm-18 mm, preferably 3 mm-12 mm. The papers for the filter material according to the invention can either consist of 100% natural, synthetic or inorganic fibers, but any mixture of these types of fibers is also possible. The expert knows the right composition based on his knowledge and experience depending on the required paper properties targeted select. The paper layer can consist of several layers, which are produced and brought together either in a paper machine with a suitable headbox or made up of individual paper webs which are joined together in a separate operation. The individual layers can be designed differently in their properties.
  • To increase the mechanical strength, the rigidity and the resistance to hot liquids, the papers for the filter material according to the invention are advantageously impregnated. Suitable impregnating agents are the substances known for filter papers, for example phenol resins or epoxy resins from alcoholic solutions, but also aqueous dispersions of, for example, acrylates, phenolic resins, polyvinyl chloride, polyvinyl acetates. Another possible class of impregnating agent are aqueous solutions of, for example, polyvinyl alcohol, melamine resin, and Marnstoffharz. To improve the wettability and thus increase the flow rate, the impregnation by suitable additives such. B. surface-active substances or fluorocarbon resins are hydrophilic or oleophilic. If the need exists, the impregnation can be mixed with a suitable flame retardant. The impregnation takes place according to the known prior art. The typical proportion of the dry impregnating agent in the total weight of the paper is 0.5-50% by weight, preferably 5-40% by weight.
    Surface mass after DIN EN ISO 536
    Thickness after DIN EN ISO 534
    Air permeability after DIN EN ISO 9237 at 200 Pa pressure difference
    Separation efficiency according to ISO 4020 with 100 cm 2 sample surface and 90 ml / min volumetric flow, test end after 1 bar differential pressure rise.
    Initial separation efficiency of 4 μm particles and dust storage capacity ISO 19438 with 200 cm 2 sample area, 100 mg / l upflow concentration and 0.71 l / min volumetric flow. Test end at 0.7 bar differential pressure rise.
    Particle delivery after the Guideline VDA Volume 19 with the test conditions according to Table 1 Table 1 Extraction method Rinse (flow) rinse Haku 1025-920 (cold cleaner) washing liquid 5 l flow velocity 1 l / min sample area 20 cm 2 Membrane type AE98 membrane filter (cellulose nitrate) 5 μm Microscopic analysis X: 6.3 μm / Pxl Y: 6.3 μm / Pxl Auswertedurchmesser 44.0
  • Water separation after ISO 16332 with the test conditions according to Table 2, measured on flat samples. The sample is clamped so that it is flowed perpendicular to its surface. Table 2 measuring temperature 23 ° C ± 2 ° C measuring liquid Commercially available diesel fuel with a surface tension of 15 mN / m ± 3 mN / m Pressure difference between the two apertures 0.26 bar flow 1100 ml / min inflow 5 ml / cm 2 min Water metering to diesel fuel 1500 ppm ± 170 ppm Medium droplet size 60 μm
  • The porosity is calculated from the actual density of the filter medium and the average density of the fibers used according to the following formula: Porosity = (1 - density filter medium [g / cm 3 ] / density fibers [g / cm 3 ]) · 100%
  • The proportion of the impregnating agent in a paper is calculated according to the following formula: Impregnating agent content in% = (FM Imp./FM paper) · 100% With
  • FM Imp. =
    Mass of dry impregnating agent per m 2 of paper
    FM paper
    = Basis weight of the impregnated paper
  • Examples
  • Example 1 (comparative example)
  • The screen side of a first layer of a meltblown web viewed in the direction of flow was spot-welded to the upper side of a second layer of filter paper by means of a cocoon. The first layer was a meltblown nonwoven made of polybutylene terephthalate Celanex 2008 with a basis weight of 50 g / m 2 , a thickness of 0.25 mm, a porosity of 85% and an air permeability of 200 l / m 2 s. For the second layer, a 100% cellulose phenolic resin impregnated paper was used. The paper is available under the name K13i15SG from the company NEENAH Gessner GmbH, Bruckmühl and has a basis weight of 235 g / m 2 , a thickness of 0.55 mm, a porosity of 72%, an air permeability of 8 l / m 2 s and a resin content of 15% by weight.
  • The entire filter material thus had a basis weight of 285 g / m 2 , a thickness of 0.75 mm and an air permeability of 8 l / m 2 s. This filter material is available under the name K13B50A from the company NEENAH Gessner GmbH, Bruckmühl.
  • At this filter material, the dust storage capacity was after ISO 4020 , the initial degree of separation for 4 μm particles ISO 19438 , the dust storage capacity according to ISO 19438, the particle delivery after VDA Volume 19 and the water separation after ISO 16332 certainly. The result is shown in Table 3.
  • Example 2 (Invention)
  • In addition, a calendered meltblown was glued onto the filter medium from Example 1 in such a way that the filter paper layer came to rest between the upstream meltblown web and the downstream calendered meltblown web. The calendered meltblown web thus formed the third layer in the flow direction. It consisted of polybutylene terephthalate Celanex 2008 and had a basis weight of 100 g / m 2 . Before calendering, the air permeability was 70 l / m 2 s and the thickness was 0.45 mm. The calender rolls were not heated during calendering. After calendering with 170 N / mm line pressure, the thickness was 0.16 mm, the air permeability 9 l / m 2 s and the porosity 55%.
  • For bonding the calendered meltblown web with the filter paper, a moisture-curing polyurethane adhesive type PUR 700.7 from Kleiberit was used. The application was carried out via a spray nozzle in the form of threads with a coating weight of 7 g / m 2 . The entire filter material had a basis weight of 395 g / m 2 , a thickness of 0.8 mm and an air permeability of 4.5 1 / m 2 s. At this filter material, the dust storage capacity was after ISO 4020 , the initial degree of separation for 4 μm particles ISO 19438 , the dust storage capacity according to ISO 19438, the particle delivery after VDA book 19 and the water separation after ISO 16332 certainly. The result is shown in Table 3. Table 3 Example 1 (comparison) Example 2 (Invention) Initial separation degree according to ISO 19348 95% 99.3% Dust storage capability according to ISO 19348 1.9 g 2.0 g Dust storage capability according to ISO 4020 500 s 450 s Particle delivery for 10-15 μm particles 1735 particles 1349 particles Particle delivery for 15-25 μm particles 490 particles 380 particles Particle delivery for 25-50 μm particles 331 particles 248 particles water separation 81.7% 98.95%
  • As can be seen from Table 3, the filter material according to the invention (Example 2) shows a clear improvement in the degree of separation ISO 19348 , the particle delivery in all particle size ranges and the water separation. It is astonishing that, despite the significantly higher separation efficiency according to ISO 19348 compared to Example 1, the dust storage capacity both according to ISO 19348 and after ISO 4020 stays almost the same. This is remarkable because an increase in the degree of separation usually results in a reduction in the dust storage capacity.
  • QUOTES INCLUDE IN THE DESCRIPTION
  • This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.
  • Cited patent literature
    • DE 4440432 A1 [0008]
    • WO 2002060559 A2 [0009]
    • DE 202007013215 U1 [0010]
    • DE 19752143 A1 [0012]
    • EP 1133342 B1 [0013]
    • DE 102009006583 A1 [0014, 0014]
    • US 4244820A [0015]
  • Cited non-patent literature
    • ISO 19438 [0002]
    • VDA Volume 19 [0005]
    • ISO 4020 [0018]
    • ISO 19438 [0018]
    • VDA Volume 19 [0018]
    • ISO 16332 [0018]
    • "Nonwovens, W. Albrecht, H. Fuchs, W. Kittelmann, Wiley-VCH, 2000. [0037]
    • Van A. Wente, "Superfine Thermoplastic Fibers", Industrial Engineering Chemistry, Vol. 48, pp. 1342-1346 [0039]
    • DIN EN ISO 536 [0042]
    • DIN EN ISO 534 [0042]
    • DIN EN ISO 9237 [0042]
    • ISO 19438 [0042]
    • Guideline VDA Volume 19 [0042]
    • ISO 16332 [0043]
    • ISO 4020 [0048]
    • ISO 19438 [0048]
    • VDA Volume 19 [0048]
    • ISO 16332 [0048]
    • ISO 4020 [0050]
    • ISO 19438 [0050]
    • VDA Book 19 [0050]
    • ISO 16332 [0050]
    • ISO 19348 [0051]
    • ISO 4020 [0051]

Claims (14)

  1. Multilayer filter material for liquid filtration with at least one first layer, at least one second layer and at least one third layer, wherein seen in the direction of flow, the first layer comprises a wet or dry laid web, the second layer a wet laid nonwoven fabric of cellulose or synthetic fibers or inorganic fibers or a Mixture thereof comprises and the third layer comprises a calendered Meltvlownvlies.
  2. Filter material according to claim 1, characterized in that the first layer is a meltblown nonwoven.
  3. Filter material according to claim 1, characterized in that the first layer comprises a filter paper.
  4. Filter material according to claim 1, characterized in that the first layer consists of a meltblown nonwoven and an impregnated filter paper, wherein the meltblown nonwoven is first flown.
  5. Filter material according to one of the preceding claims, characterized in that the second layer consists of several different paper layers.
  6. Filter material according to one of the preceding claims, characterized in that the second layer is impregnated.
  7. Filter material according to one of the preceding claims, characterized in that the third layer is hydrophilic.
  8. Filter material according to one of claims 1 to 6, characterized in that the third layer is hydrophobic.
  9. Filter material according to one of the preceding claims, characterized in that the first layer has a basis weight of 10 g / m 2 -350 g / m 2 , a thickness of 0.05 mm-4.0 mm, an air permeability of 50 l / m 2 s-2000 l / m 2 s and a porosity of 60% -97%.
  10. Filter material according to one of the preceding claims, characterized in that the second layer has a basis weight of 50 g / m 2 -300 g / m 2 , a thickness of 0.2 mm-2.0 mm, an air permeability of 2 l / m 2 s-50 l / m 2 s and has a porosity of 65% -95%.
  11. Filter material according to one of the preceding claims, characterized in that the third layer has a basis weight of 20 g / m 2 -300 g / m 2 , a thickness of 0.03 mm-0.3 mm, an air permeability of 2 l / m 2 s-100 l / m 2 s and a porosity of 10% -55%.
  12. Filter material according to one of the preceding claims, characterized in that the filter material has a basis weight of 50 g / m 2 -800 g / m 2 , a thickness of 0.3 mm-6.0 mm and an air permeability of 1 l / m 2 s -50 l / m 2 s.
  13. Filter material according to one of the preceding claims, characterized in that the filter material has an initial separation efficiency for 4 μm particles according to ISO 19438 of at least 90 a dust storage capacity according to ISO 19438 of at least 1.5 g per 200 cm 2 sample surface, a dust storage capacity according to ISO 4020 of at least 300 s, a particle discharge according to VDA Volume 19 of at most 1500 particles of size 10-15 μm, of at most 450 particles of size 15-25 μm and of at most 300 particles of size 25-50 μm.
  14. Filter element made of a filter material according to one of the preceding claims.
DE201210010307 2012-05-24 2012-05-24 Multilayer filter material of filter element for liquid filtration, has main portion that is provided with pre-filter layer, main filter layer and absolute hydrophilic or hydrophobic filter layer Pending DE102012010307A1 (en)

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9149749B2 (en) 2012-11-13 2015-10-06 Hollingsworth & Vose Company Pre-coalescing multi-layered filter media
US9149748B2 (en) 2012-11-13 2015-10-06 Hollingsworth & Vose Company Multi-layered filter media
WO2016159794A2 (en) 2015-03-27 2016-10-06 Secura B.C. Sp. Z O.O. Multilayer, non-woven filter for emulsion separation
DE102015012643A1 (en) 2015-09-30 2017-03-30 Mann + Hummel Gmbh Filter medium and use of the filter medium
WO2017050602A1 (en) * 2015-09-22 2017-03-30 Mahle International Gmbh Filter medium
US10195542B2 (en) 2014-05-15 2019-02-05 Hollingsworth & Vose Company Surface modified filter media
US10399024B2 (en) 2014-05-15 2019-09-03 Hollingsworth & Vose Company Surface modified filter media

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DE102009032778A1 (en) * 2009-07-10 2011-01-27 Carl Freudenberg Kg Filter cartridge for filtering tough and chemical aggressive liquids, has star-shaped folded filtering medium provided between two end caps and formed by non-woven fabric that comprises elementary fibers of splittable multi-component fiber
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Richtlinie VDA Band 19
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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9149749B2 (en) 2012-11-13 2015-10-06 Hollingsworth & Vose Company Pre-coalescing multi-layered filter media
US9149748B2 (en) 2012-11-13 2015-10-06 Hollingsworth & Vose Company Multi-layered filter media
US10080985B2 (en) 2012-11-13 2018-09-25 Hollingsworth & Vose Company Multi-layered filter media
US10279291B2 (en) 2012-11-13 2019-05-07 Hollingsworth & Vose Company Pre-coalescing multi-layered filter media
US10399024B2 (en) 2014-05-15 2019-09-03 Hollingsworth & Vose Company Surface modified filter media
US10195542B2 (en) 2014-05-15 2019-02-05 Hollingsworth & Vose Company Surface modified filter media
WO2016159794A2 (en) 2015-03-27 2016-10-06 Secura B.C. Sp. Z O.O. Multilayer, non-woven filter for emulsion separation
WO2017050602A1 (en) * 2015-09-22 2017-03-30 Mahle International Gmbh Filter medium
DE102015012643A1 (en) 2015-09-30 2017-03-30 Mann + Hummel Gmbh Filter medium and use of the filter medium

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