DE102007018938A1 - Air filter has a pleated/corrugate filter body, with a stiffener at the inflow and/or outflow side of an irradiation cross-linked polymer with a bulking material - Google Patents

Abstract

The air filter element (1), with a pleated or corrugated filter body (2), has at least one stiffener (4) across the pleats/corrugations at the inflow and/or outflow side. The stiffener is an irradiation cross-linked polymer with at least one bulking material. The bulking material can be of SiO 2, talcum, glass, wollastonite, Al 2O 3, kaolin, calcium sulfate, calcium carbonate, barium sulfate, aluminum silicate, aluminum nitrite, aluminum hydroxide and their mixtures.

Description

The The invention relates to a filter element for use in a filter device for cleaning air with a folded or corrugated filter body and with at least one stiffening element on the inflow and / or downstream side of the filter body, the transversely is arranged to the longitudinal direction of the waves or folds, wherein the stiffening element is a radiation cross-linked polymer and comprises at least one filler.

The The invention further relates to a method for producing the same Filter element and the use of this filter element as Cabin air filter, circulating air filter, clean room filter, exhaust air filter, domestic filter and / or vacuum cleaner filters.

Such filter elements are known in various embodiments. So-called adhesive beads are described in the prior art to prevent deformation of air filters when flowing through or to allow the use of non-rigid filter materials. The adhesive beads keep the filter element in its shape even at high flow rates and prevent damage to the filter by deformation. The prior art describes hot-melt adhesives for producing the stiffening elements (US Pat. DE 197 13 238 A1 ). However, these adhesives have the great disadvantage that they can lose their inherent rigidity when heated and thus the stabilizing effect can be lost at higher temperatures. A similar problem occurs when thermostable stiffening elements, for example in non-woven form, which are attached with a hot melt adhesive to the filter element, are used for stabilization.

Furthermore, the use of thermosetting polymers is described. However, such polymers are not suitable for forming stiffening elements in filter materials which are not heat-resistant ( US 2006/0005517 A1 ).

task The present invention is therefore, with folded elements or to provide corrugated filter body, which also are permanently stable at higher temperatures.

A Another object of the present invention is to provide a simplified To provide methods of making filter elements.

These Task is solved by a filter element for use in a filter device for cleaning air with a folded or corrugated filter body and at least one stiffening element on the inflow and / or outflow side of the filter body, arranged transversely to the longitudinal direction of the waves or folds wherein the stiffening element is a radiation crosslinked polymer and at least one filler.

Further Embodiments of the invention Filter element are specified in the subclaims 2 to 13.

The The invention also relates to a filter element intermediate for the preparation of the invention Filter element with a folded or corrugated filter body and with at least one, preferably elongated, stiffening element on the inflow and / or outflow side of the filter body, arranged transversely to the longitudinal direction of the folds or waves wherein the stiffening element is a radiation crosslinkable polymer precursor and comprises at least one filler.

By Irradiation is the radiation crosslinkable polymer precursor in a radiate cross-linked polymer, taking off the filter element intermediate according to the invention the filter element according to the invention is formed.

Under the term "transverse to the longitudinal direction of the folds or waves" in the context of the invention is to be understood that the stiffening elements oblique, diagonal, substantially vertical or vertical arranged to the longitudinal direction of the folds or waves are.

Under The term "folded filter body" are preferably Pleated or zigzag folded filter body to understand.

at an embodiment, the inventive Filter element elongated stiffening elements on which from one end to the other end of the filter body extend. Preferably, the stiffening elements extend in one straight line.

at In one embodiment, the stiffening elements are in formed essentially free of pores.

at In one embodiment, the stiffening element is self-adhesive and is preferably without an additional adhesive fixed on the filter body.

at an embodiment comprises the filter element comprising at least one stiffening element on the Anström- and on the downstream side of the filter body.

In one embodiment, the filter element according to the invention has at least 2 stiffening elements. Preferably, the inventions according to the filter element 3 or 4 Stiffening elements on. Preferably, the stiffening elements are arranged on the edge of the filter element. In one embodiment of the filter element according to the invention, the edges of the stiffening elements are arranged at a distance of at most 5 cm, preferably at a distance of 5 cm to 2 cm from each other.

at In one embodiment, the filter body additionally a side strip in the side opening plane the folds or waves of the filter body is arranged. In a preferred embodiment, the filter body additionally two side stripes on, on both sides the side of the opening planes of the folds or ripples of the Filter body are arranged.

Under Side strips in the sense of the present invention are extruded and / or strip-shaped elements that continue to understand contribute to the stabilization of the filter body. Preferably The reinforcing elements are made of the same material as the stiffening elements.

at an embodiment of the invention Filter element consists of the filter body of a flexible Material.

The Reinforcement elements serve as spacers of the folds or waves to each other and stabilize the arrangement of the filter body in the filter element, in particular in the flow with a liquid or gaseous fluid.

The Stiffening elements are preferably in elongated form before and can be applied in strand and / or strip form be and / or arranged. Preferably, the stiffening elements a thickness in a range of 0.1 cm to 0.8 cm, more preferably in a range of 0.3 to 0.5 cm, on.

The radiation-crosslinkable polymer precursor which is to the radiation crosslinked Polymer is cured, includes a filler in an amount such that, prior to beam crosslinking, the radiation-crosslinkable polymer precursor and the filler form a viscous molding compound which can be applied to the filter body and essentially has no flow behavior.

Preferably the radiation-crosslinkable polymer precursor remains at least 95% by volume, preferably 100% by volume, based on the total volume the radiation-crosslinkable polymer precursor, in the region in which the radiation-crosslinkable polymer precursor was originally applied. In one embodiment of the invention Filter element has the mass of the radiation-crosslinkable polymer precursor and the filler thixotropic properties.

at One embodiment is the radiation-cured Polymer in the form of a network.

at In one embodiment, the stiffening elements comprise 12.5 to 27 wt .-% filler, based on the total weight the radiation-crosslinked polymer and the filler.

When Filler is preferably an inorganic, preferably mineral filler, used. The filler is present in particulate form. The particle size is preferably in a range of 10 nm to 500 μm, more preferably in a range of 20 nm to 50 μm, most preferably in a range from 1 μm to 50 μm, in front.

In one embodiment, the filler is selected from the group consisting of SiO ₂ , talc, glass, wollastonite, Al ₂ O ₃ , kaolin, calcium sulfate, calcium carbonate, barium sulfate, aluminum silicate, aluminum nitrite, aluminum hydroxide, and mixtures thereof.

at One embodiment is the radiation crosslinked polymer from the group consisting of polyacrylates, poly (meth) acrylates, Polyolefins, polyvinyl ethers, polyvinylamides, unsaturated Polyester and mixtures thereof, selected.

at a preferred embodiment comprises the radiation crosslinked Polymer polypropylene or polypropylene units.

Further are polymers based on (meth) acrylates, such as polyesters (methacrylates), Polyethers (methacrylates), urethane (methacrylates), epoxy (methacrylates), Silicone (methacrylates), in particular their block polymers, graft polymers and / or copolymers, preferred.

The irradiated polymer may further include pigments, dyes, stabilizers, etc. include.

The Arrangements and chemical compositions of the invention Filter element are also used for the filter element intermediate used with the difference that in place of the radiation crosslinked Polymers a radiation-crosslinkable polymer precursor is used.

at One embodiment is the radiation-crosslinkable polymer precursor from monomers, oligomers and / or crosslinkable polymers of the group, consisting of acrylates, (meth) acrylates, olefins, vinyl ethers, Vinyl amides, unsaturated esters and mixtures thereof.

The Radiation-crosslinkable compounds can be more reactive Groups, e.g. As melamine, isocyanate, anhydride, alcohol, carboxylic acid groups for additional thermal stabilization, z. B. by the chemical reaction of alcohol, carboxylic acid, amine, Anhydride, isocyanate and / or melamine groups.

at In one embodiment, the stiffening elements comprise before the radiation crosslinking 3 to 5 wt .-% of photoinitiators, based on the total weight of the radiation-crosslinked polymer and the filler.

When Photoinitiators are suitable for. Benzophenone, alkylbenzophenone, halomethylated benzophenones, Michler ketones, anthrone, and halogenated Benzophenones. Also suitable are benzoin and its derivatives. Also effective photoinitiators are anthraquinone and many of its Derivatives, for example β-methylanthraquinone, tert-butylanthraquinone and Anthrachinoncarbonsäureester and particularly effective Photoinitiators having an acylphosphine oxide group, such as acylphosphine oxide or bis-acylphosphine oxide, e.g. B. 2,4,6-trimethylbenzoyldiphenylphosphine oxide.

at In one embodiment, the stiffening elements comprise in addition to the radiation-crosslinkable polymer precursor and the filler nor a carrier material, which stabilized to be hardened stiffening elements and is removed after their radiation crosslinking.

at In one embodiment, the filter body from a thermoplastic polymer. The combination of a thermoplastic Filter body with radiation-crosslinked stiffening elements allows the production and use of a stable Filter element at lower temperatures, which does not cause deformation lead the filter body.

at In one embodiment, the radiation-crosslinked stiffening elements thermosetting properties. The filter element will therefore also kept in shape at higher temperatures.

• a) Bereitstellen eines gefalteten oder gewellten Filterkörpers,
• b) Aufbringen mindestens eines Versteifungselementes, in vorzugsweise langgestreckter Form, auf den Filterkörper auf der Anström- und/oder Abströmseite quer zur Längserstreckung der Wellen und Falten, wobei das Versteifungselement eine strahlenvernetzbare Polymervorstufe und mindestens einen Füllstoff umfasst, und
• c) das Versteifungselement durch Bestrahlung gehärtet wird.

The invention is further achieved by a method for producing a filter element with a folded or corrugated filter body, which comprises the following steps:

• a) providing a folded or corrugated filter body,
• b) applying at least one stiffening element, in preferably elongated form, to the filter body on the inflow and / or outflow side transversely to the longitudinal extent of the waves and folds, wherein the stiffening element comprises a radiation-crosslinkable polymer precursor and at least one filler, and
• c) the stiffening element is cured by irradiation.

The described for the filter element according to the invention Arrangements and chemical compositions can also used in the inventive method become.

Preferably has the radiation-crosslinkable polymer stage with the filler thixotropic properties. By adding the filler is the viscosity of the radiation-crosslinkable polymer precursor preferably adjusted so that the radiation-crosslinkable polymer precursor can be applied to the filter body, without in the To flow wrinkles and waves. Preferably, the applied remains Polymer precursor to 95%, preferably 100% at their place of application. As a result, for example, the implementation of a continuous Procedure allows.

In one embodiment of the method according to the invention, the radiation crosslinking is carried out under protective gas. As protective gas, for example, noble gases, such as argon, hydrocarbons and halogenated hydrocarbons, CO ₂ and / or nitrogen come into consideration. When using shielding gas, radiation with a lower energy can be used for the beam crosslinking.

The Duration, intensity and wavelength of irradiation depends on the desired degree of crosslinking as well from the polymer precursor used.

additionally For example, the radiation-crosslinkable polymer precursor may contain photoinitiators.

So far the radiation-crosslinkable polymer precursors contain photoinitiators, These photoinitiators should have absorption wavelengths in the range of the emitted light. Suitable photoinitiators are in particular the above-mentioned photoinitiators with acylphosphine oxide groups.

The Stiffening elements comprising the radiation-crosslinkable polymer precursor and the filler, can according to usual Procedures are applied to the filter body. For example the application can be done from above. The stiffening elements become from the top of the filter body, with the fold edges or bends upwards, applied. The application of the Stiffening elements on the fold edges or bends of the filter body can also be done by the stiffening elements on a Carrier element are applied and then from above the filter body with the fold edges or bends is placed down on the stiffening elements.

The Viscosity of the radiation-crosslinkable polymer precursor with The filler is preferably chosen so that the glue does not enter the folds and / or troughs flows in, but only the upward facing Edges and / or bends of the filter body connects. The application of the radiation-crosslinkable polymer precursor with the filler can be extruded, and / or strip-shaped. For example. can a nozzle for applying the radiation-crosslinkable polymer precursor be used with the filler.

The Radiation crosslinking can be performed with electron beams, X-ray or gamma rays, and / or UV radiation.

at In one embodiment, the radiation crosslinking takes place a wavelength less than 400 nm. Preferably the wavelength in a range of 30 to 380 nm.

When Radiation source can be bulbs that have a line spectrum or a broadband spectrum. For example. can as a source of radiation incandescent lamps, halogen lamps, xenon lamps, Mercury vapor lamps, pulsed lamps are used.

at In a preferred embodiment, the irradiation takes place indirectly through the filter body. Preferably, the Filter body made of a radiation-permeable Material. Particularly preferably, the filter body made of polypropylene or polypropylene.

at In one embodiment, the filter body made of a thermoplastic material.

at In one embodiment, the invention Process continuously preferably carried out with a conveyor belt.

at In one embodiment, the radiation-crosslinkable polymer precursor with the filler by spraying on the filter body applied, wherein a directed onto the transfer belt nozzle used to apply the adhesive.

Of the Application of the adhesive can also be done indirectly. For this purpose is the adhesive by means of a nozzle, for example, strip-shaped applied to a transfer tape. About pressure of the nozzle and speed of the transfer belt can be the amount of the applied Adhesive be regulated. Following the adhesive application the impressions of the filter body in the radiation-crosslinkable polymer precursor containing a filler contains. For the stabilization of filters is a regular distance of filter folds or Filter waves advantageous.

The Combination of a transfer belt and cross-linking under inert gas allows the production of filter elements in one very economical process.

Preferably it is the filter element to an air filter.

The Filter element can be used as cabin air filter, recirculation filter, clean room filter, Exhaust filter, housing filter and / or vacuum cleaner used become.

The The following examples are intended to explain the invention, but in no way limit.

Examples

example 1

• a) Das Filterelement wurde vom Transportband abgenommen und die Streifen der strahlenvernetzbaren Polymervorstufe wurden durch direkte, einminütige Bestrahlung mit einem langwellig emittierenden Strahler (Gallium dotiert) mit ca. 2000 Watt Leistung bei einer Wellenlänge von ca. 380 nm ausgehärtet.
• b) Das Filterelement wurde auf dem Transportband belassen und die strahlenvernetzbare Polymervorstufe wurde von der Seite des Filterkörper bestrahlt, der nicht mit der Polymervorstufe belegt war (3). Überraschenderweise wurde festgestellt, dass die Vernetzung bei Polypropylenfiltermaterialien auch durch die indirekte Bestrahlung durch den Filterkörper erfolgen kann, falls die UV-Transparenz dieses Merkmals hierfür ausreicht. Auf diese Weise können Filterelemente hergestellt werden, bei denen die Abnahme vom Transferband erst nach der Vernetzung der Streifen erfolgte. Dies ermöglicht eine extrem wirtschaftliche Herstellung der Filterelemente in einem kontinuierlichen Prozess.
• c) Die Vernetzung wurde wie unter a) beschrieben durchgeführt mit dem Unterschied, dass das Filterelement mit 400 Watt 30 Sekunden in einer Wanne unter CO₂-Atmosphäre bestrahlt wurde. Die Vernetzung war dabei vergleichbar zu der längeren hochenergetischen Bestrahlung an Luft in Schritt a). Die Variante c) zeigt deutlich, dass die Leistung des UV-Strahlers reduziert werden kann, falls die Vernetzung unter Schutzgasatmosphäre durchgeführt wird.

A commercially available UV-curable acrylate-based lacquer (BASF 5191/1) while silica gel (Levasil 200, HC Starck about 40 nm average particle diameter) was added until a pasty mixture with thixotropic properties. In this example, the weight fraction of silica gel was 18% by weight, based on the weight of the pasty mixture. 4% by weight, based on the total weight of the paste-like mixture, of an acyl-oxide-based photoinitiator having an absorption maximum in the long-wave UV range (about 380 nm) were added to the pasty mixture. The pasty polymer precursor was applied by means of a syringe device in strand form on a transfer belt. Stiffening elements with a width of approx. 4 mm and a height of approx. 6 mm were formed. In the stiffening elements, a folded cabin air filter made of polypropylene was inserted, so that the pleat tips were arranged perpendicular to the stiffening elements. The crosslinking of the stiffening element was carried out by three different methods:

• a) The filter element was removed from the conveyor belt and the strips of the radiation-crosslinkable polymer precursor were cured by direct, one-minute irradiation with a long-wavelength emitting radiator (gallium doped) with about 2000 watts of power at a wavelength of about 380 nm.
• b) The filter element was left on the conveyor belt and the radiation-crosslinkable polymer precursor was irradiated from the side of the filter body that was not occupied by the polymer precursor ( 3 ). Surprisingly, it has been found that the crosslinking in polypropylene filter materials can also be effected by the indirect irradiation through the filter body, if the UV transparency of this feature is sufficient for this purpose. In this way, filter elements can be produced in which the decrease of the transfer belt only after the crosslinking of the Strei took place. This allows extremely economical production of the filter elements in a continuous process.
• c) Crosslinking was carried out as described under a) with the difference that the filter element was irradiated with 400 W for 30 seconds in a trough under CO ₂ atmosphere. The crosslinking was comparable to the longer high-energy irradiation in air in step a). Variant c) clearly shows that the power of the UV emitter can be reduced if the crosslinking is carried out under a protective gas atmosphere.

Example 2

Around The stiffening effect was tested on a filter body made of polypropylene with a surface area of 300 × 210 mm 2 strips of a commercially available UV-crosslinkable Lacquer (BASF 5191/1) with 20 wt .-% barium sulfate (based on the total amount of the UV-crosslinkable lacquer) and with a radiation of 2000 watts, at a wavelength of approx. 380 nm, for Hardened for 1 min. Subsequently, the filter element according to the invention flows through in a climate-control cabinet of a car air conditioner. The flow through was at 60 ° C. Compared For this purpose, filter elements with stiffening elements made of thermoplastic Polyolefin-based hot melt adhesives at 60 ° C under the same Conditions tested. These were partly from the fan destroyed the air conditioning due to massive deformation. In contrast, the inventive had Filter element excellent dimensional stability. The Example clearly shows the improved stability of Filter elements, which with stiffening elements of a radiation crosslinked Polymer are made with a filler.

characters

In 1a ) 1b ) and 2 ) Embodiments of the filter element are shown.

It shows 1a ) is a schematic side view of an embodiment of the filter element according to the invention. The filter element 1 has a folded filter body 2 with fold edges 3 and with an elongated stiffening element 4 on.

1b ) shows how 1a ) a filter element is a schematic side view of an embodiment of the filter element according to the invention with the difference that the filter body is corrugated.

2 shows a perspective view of a filter element according to the invention 1 according to the embodiment 1a) with 2 stiffening elements 4 ,

3 shows a plant for the continuous production of the filter elements 1 , wherein the radiation crosslinking through the filter body 2 is performed through. This is initially by an applicator 5 a radiation-crosslinkable polymer precursor with filler as stiffening element 4 on the conveyor belt 6 applied. Subsequently, the filter body 2 on the stiffening element 4 placed. The conveyor belt 6 goes through a tub with inert gas atmosphere 8th and is from the top with a UV light source 7 irradiated. The finished filter element 1 leaves on the conveyor belt 6 the tub with the protective gas atmosphere 8th ,

1

filter element

2

filter body

3

fold edge

4

stiffener

5

applicator radiation-crosslinkable polymer

6

conveyor belt

7

UV-light source

8th

tub with protective gas atmosphere

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 19713238 A1 [0003]
• US 2006/0005517 A1 [0004]

Claims (22)

Filter element ( 1 ) for use in a filter device for cleaning air with a folded or corrugated filter body ( 2 ) and with at least one stiffening element ( 4 ) on the inflow and / or outflow side of the filter body ( 2 ), which is arranged transversely to the longitudinal direction of the waves or folds, wherein the stiffening element ( 4 ) comprises a radiation crosslinked polymer and at least one filler. Filter element ( 1 ) according to claim 1, comprising at least one stiffening element ( 4 ) on the inflow and outflow side of the filter body ( 2 ). Filter element ( 1 ) according to claim 1 or 2, wherein the radiation-crosslinked polymer has thermosetting properties. Filter element ( 1 ) according to any one of the preceding claims, wherein the stiffening element ( 4 ) is formed substantially free of pores. Filter element ( 1 ) according to any one of the preceding claims, wherein the stiffening element ( 4 ) without an additional adhesive on the filter body ( 2 ) is fixed. Filter element ( 1 ) according to any one of the preceding claims, wherein the stiffening element ( 4 ) 12.5 to 27% by weight of filler based on the total weight of the filler and the radiation crosslinked polymer. Filter element ( 1 ) according to one of the preceding claims, wherein the filler is selected from the group consisting of SiO ₂ , talc, glass, wollastonite, Al ₂ O ₃ , kaolin, calcium sulfate, calcium carbonate, barium sulfate, aluminum silicate, aluminum nitrite, aluminum hydroxide and mixtures thereof. Filter element ( 1 ) according to one of the preceding claims, wherein the radiation-crosslinked polymer is selected from the group consisting of polyacrylates, poly (meth) acrylates, polyolefins, polyvinyl ethers, polyvinylamides, unsaturated polyesters, and mixtures thereof. Filter element ( 1 ) according to claim 8, wherein the radiation crosslinked polymer is a polypropylene. Filter element ( 1 ) according to any one of the preceding claims, wherein the stiffening element ( 4 ) prior to radiation crosslinking, contains from 3 to 5% by weight of photoinitiators, based on the total weight of the photoinitiators and of the radiation-crosslinked polymer. Filter element ( 1 ) according to one of the preceding claims, wherein the filter body ( 2 ) consists of a thermoplastic polymer. Filter element ( 1 ) according to one of the preceding claims, further comprising a side strip, which at the lateral opening plane of the folds or waves of the filter body ( 2 ) is arranged. Filter element ( 1 ) according to one of the preceding claims 1 to 11, further comprising 2 side strips, which on both sides at the lateral opening planes of the folds or waves of the filter body ( 2 ) are arranged. Filter element intermediate for the production of a filter element ( 1 ) according to one of claims 1 to 13 with a folded or corrugated filter body ( 2 ) and at least one elongate stiffening element ( 4 ) on the inflow and / or outflow side of the filter body ( 2 ), which is arranged transversely to the longitudinal direction of the folds or waves, wherein the stiffening element ( 4 ) comprises a radiation-crosslinkable polymer precursor and at least one filler. Method for producing a filter element with a folded or corrugated filter body comprising following steps: a) Provide a folded or corrugated Filter body, b) applying at least one stiffening element on the filter body on the inflow and / or outflow side transverse to the longitudinal extent of the waves and folds, wherein the stiffening element is a radiation-crosslinkable polymer precursor and at least one filler, and c) the Stiffening element is cured by irradiation. The method of claim 15, wherein the radiation crosslinkable Polymer precursor of monomers, oligomers and crosslinkable Polymers of the group consisting of polyacrylates, poly (meth) acrylates, Polyolefins, polyvinyl ethers, polyvinylamides, unsaturated Polyester and mixtures thereof is selected. Method according to one of claims 15 to 16, wherein the beam crosslinking is carried out under protective gas becomes. Method according to one of claims 15 to 17, wherein the radiation-crosslinkable polymer precursor contains from 3 to 5% by weight of photoinitiators, based on the total weight of the photoinitiators and the radiation-crosslinkable Polymer precursor be added. The method of any one of claims 15 to 18, wherein the irradiation is indirect through the filter Lement and / or the filter body takes place. Method according to one of claims 15 to 19, the process being a continuous process. Method according to one of claims 15 to 20, wherein the radiation-crosslinkable polymer precursor is strand-like or is applied in strips to a transfer belt, then the folded or corrugated filter body is applied to the radiation-crosslinkable polymer precursor and the polymer precursor by irradiation, preferably of the radiation-crosslinkable polymer precursor facing away from the filter body, is cured and then the filter element is detached from the transfer belt. Use of the filter element according to one of the claims 1 to 13 as cabin air filter, circulating air filter, clean room filter, exhaust air filter, Housing filter and / or vacuum cleaner filter.