DE102011053977A1 - Method used for arresting functional particles in nonwoven material for e.g. dust-collector bag, providing activated carbon particles to nonwoven material and introducing heated functional particles to nonwoven material - Google Patents

Abstract

Activated carbon particles are provided to a nonwoven material (1). The arrest is carried out by fusion process by heating functional particles and introducing heated functional particles (4) to nonwoven material.

Description

The invention relates firstly to a method for arresting functional particles, in particular activated carbon particles, on a nonwoven material, the arrest being effected by a melting process triggered in the nonwoven material according to heating of the functional particles.

Methods of the type in question are known. These are used in particular for the production of filter materials, more particularly consisting of a nonwoven material, which nonwoven material functional particles of the type in question are assigned. Such functional particles are in particular particles for odor absorption, so on, in particular activated carbon particles. In addition, functional particles, including particles of expanded clay, for example, are also odor-emitting particles or else thermoplastic plastic particles which are provided with perfume. Furthermore, nonwovens, in particular filters, are known in this regard, in which the functional particles are adhered in or on the nonwoven material in order to achieve the most uniform and orderly distribution of the functional particles on the nonwoven material. For this purpose, known methods provide for bonding the functional particles to the nonwoven material. In a further known method, the adhesion is effected according to heating of the functional particles so as to initiate a melting process in contact with the nonwoven material, in particular a melting process of the nonwoven material coated with functional particles. In this case, the heating of the functional particles is carried out in assignment position of the same to the nonwoven material, with the common heating of functional particles and nonwoven material. In a bonding, but also in a fusion according to the above-described method, the desired air permeability, especially in filter materials, is adversely affected to an undesirable extent.

In view of the prior art described above, a technical problem of the invention is seen in such a way to further improve a method of the type in question, that with further favorable air permeability of the nonwoven material, a sufficient adhesion of the functional particles to the nonwoven material can be achieved by heating ,

This problem is solved first and foremost by the subject matter of claim 1, wherein it is pointed out that functional particles which have already been heated to initiate the melting process are already introduced into or introduced into the nonwoven material. According to the proposed method, a localized melting process of the nonwoven material adhering to the functional particles is made possible by the targeted heating of the functional particles prior to contacting the nonwoven material. The functional particles are accordingly preferably heated to a temperature which triggers the functional particles adhering to the melting process in the nonwoven material upon impact of the functional particles on the nonwoven material or when introduced into the nonwoven material. It is achieved as a locally limited to the immediate contact surface of the functional particles limited fusion, which adjacent, not by the functional particles contacted areas of the nonwoven material preferably continue to have the predetermined air permeability and more preferably the predetermined degree of filtration for separating, for example, particles from an air stream. The functional particles adhere to the nonwoven material, in particular after cooling thereof to a temperature below the melting temperature of the nonwoven material on the nonwoven material, in particular as a result of a microscopic hot gluing process.

Further features of the invention are explained below, also in the description of the figures, often in their preferred association with the subject matter of claim 1 or with features of further claims. But they can also be in an assignment to only individual features of claim 1 or the respective further claim or each independently of importance.

Thus, it is further preferred that the nonwoven material is not heated or heated only to a temperature at which the melting process is not yet triggered. Accordingly, no melting process of the nonwoven material is triggered solely by a possible heating of the nonwoven material. A partial melting or melting of the nonwoven material is preferably carried out solely by contacting the heated to the melting temperature of the nonwoven material functional particles.

The nonwoven material preferably contains fusible fiber constituents by heating, in particular fiber constituents, which have a melting temperature which corresponds to or lies below the temperature of the heated functional particles when they hit the nonwoven material. Further optionally provided constituents of the nonwoven material, more preferably also fiber constituents, may have a melting temperature which is above the heating or impingement temperature of the functional particles. For example, a partial melting on impingement of heated functional particles on the nonwoven material is preferably given, preferably only a fusion of correspondingly configured fiber constituents in the contacting region. As a result, the melting surface for arresting the functional particles on the nonwoven material is further reduced, this more preferably to a level which is particularly useful Use of the particulate nonwoven material ensures the secure attachment of the functional particles to the nonwoven material, but also offers the greatest possible air permeability, in particular for the filtration of particles from a stream of air. Preferably, the fusible fibers are made of polyethylene or polypropylene. The nonwoven material can be produced in one or more layers based on optionally different nonwovens. Thus, there may be a consolidated fibrous web of fibers with synthetic fibers, viscose fibers, cellulosic fibers and / or natural fibers, which fibrous fluorine per se, for example, have an air permeability of 100 to 1500 L / dm ² × min, with a preferred basis weight of 100 g / m ² to 300 g / m ² and a preferred thickness of 0.8 mm to 3 mm. The fibers of the batt may further have a thickness of 3 microns to 50 microns (0.1 dtex to 17 dtex), this at a preferred staple length of the fibers of 30 mm to 100 mm. Also preferably melt-blown fibers are present, which consist for example of polypropylene, polyethylene, polystyrene, polycarbonate, polyurethane, polyamide, Polyehtylenterephtalat, polyvinylsiloxanes, Polybuthylenterephtalat or a mixture of these different materials. Such a filter layer preferably has an air permeability of 200 L / dm ² × min to 500 L / dm ² × min, this with a preferred basis weight of 100 g / m ² to 300 g / m ² and a thickness of more preferably 1, 0 mm to 3.0 mm. Such melt-blown fibers are microfibers with a preferred thickness of 0.1 .mu.m to 10 .mu.m, with a thickness of 0.5 .mu.m to 3 .mu.m being preferred for fibers of polyethylene terephthalate. Also, such melt-blown fibers may have a length of less than 30 mm. In an entanglement of melt-blown fibers and solidified batt, the unfragmented melt-blown structure per se may have an air permeability of 50 L / dm ² × min to 2000 L / dm ² × min, with a preferred basis weight of 5 g / m ² to 1000 g / m ² and a thickness of preferably 0.8 mm to 3 mm. In addition to melt-blown fibers, other plastic fibers, such as micro-glass fiber fleece, split-fiber or bicomponent fibers can also be used. These are for example thermally, chemically or mechanically crosslinked with each other and can continue to serve as a fine fiber fleece. In addition, an outer layer may be provided, for example, from a bung-bond nonwoven, which has good support properties.

In particular, when using the provided with the functional particles nonwoven material for filtering gases, further example, using the nonwoven material to form a filter bag for an electric vacuum cleaner is further preferably provided gaseintrittseitig, ie with respect to a filter bag inside the wall, further provided on the surface fusible fiber components at which the functional particles arrest according arrest.

The functional particles are further preferably heated to a temperature of 120 ° C to 350 ° C, more preferably 200 ° C to 250 ° C and more preferably in this heated state in an at least approximately targeted distribution, resulting from the desired amount on the disposal standing surface of the nonwoven material, applied to the nonwoven material. In order to allow any further preparation of the nonwoven material, for example for the production of a filter bag, masking of the surface of the nonwoven material to be filled with the functional particles preferably keeps subsequent connection zones, for example weld seams of a filter bag, free from functional particles, so that in these zones is counteracted after a weld a possible leak.

Preferably, for a usable area of the nonwoven material of 500 cm ² to 1500 cm ² , more preferably 900 cm ² to 1100 cm ^2, the application and fusion of 5 g to 20 g, more preferably 8 g to 12 g, especially 10 g of functional particles provided , These functional particles more preferably have a volume of 1.5 mm ³ to 3 mm ³ , more preferably 1.8 mm ³ to 2.2 mm ³ , in particular about 2 mm ³ , this at a preferred length / width / height ratio up to 2: 1: 1. This preferably corresponds to a spherical shape of 1.3 mm to 2 mm in diameter, more particularly from 1.4 mm to 1.6 mm, more preferably about 1.56 mm. Here, the available surface of the nonwoven material is sufficient for a flat application of the desired amount of functional particles, wherein more preferably after application of the functional particles and a corresponding adhesion by melting an available surface of the nonwoven material, in particular the available air-permeable surface, by a factor of 3 to 5, more preferably from 4 to 4.5, in particular 4.2 is greater than the dense with respect to the air permeability, according area occupation with the functional particles.

In a preferred embodiment, the functional particles are applied to the nonwoven material by dropping from a height of 50 mm to 150 mm, preferably about 100 mm, more preferably at an ambient and nonwoven temperature of about 20 ° C. Depending on the drop height of the functional particles, the penetration depth and / or the impact force on the nonwoven material can be adjusted. As the heated functional particles cool more strongly over a longer fall path with increasing drop height, the corresponding heating temperature of the functional particles is adapted. Essential for the proposed method is preferred slightly, in particular in a range of 20 ° C to 50 ° C above the melting temperature of the fusible fibers lying incident temperature of the functional particles, so that a melting of the fibers contacted by the functional particles is ensured. Variance of the drop height results in different penetration depths into the nonwoven material and thus changed adhesive surfaces under unchanged basic conditions. Too large an adhesive surface minimizes the free active surface of the functional particles, too small an adhesive surface results in too low holding forces for the particles on the nonwoven fibers. An adhesive surface which corresponds to 2% to 30% of the surface of the functional particle, more preferably 10% to 15%, is preferred.

More preferably, the functional particles are applied by an air flow to the nonwoven material, so in particular by a directed specifically in the direction of the surface to be coated of the nonwoven material, the nonwoven material preferably passing through the air stream. In a further preferred embodiment, a hot air stream is used for this purpose, which provides heating of the functional particles to melting temperature or, as further preferred, brakes the cooling process of the previously heated functional particles. Also, the heated functional particles can accelerated into the nonwoven material quasi injected by means of compressed air.

It is also preferred that the heated functional particles are pressed onto the nonwoven material resting, for example, defined by means of a roller, wherein the functional particles are previously applied to the nonwoven material, for example, by falling from a comparatively small height.

According to the proposed method, a localized adhesion of functional particles is possible regardless of the particle size, since only these particles are heated at least to the melting temperature of the associated nonwoven material. Accordingly, even with large particles with a (calculated) diameter of more than 0.7 mm, in particular more than 0.71 mm, localized on the contact surface limited melting of the nonwoven material can be achieved while nonwoven areas between the adhering particles not or not be melted flat, resulting in a sufficiently high air permeability.

The proposed method further advantageously offers the possibility of using a visual inspection of the area occupation instead of a gravimetric examination of the actual coating of the nonwoven material with functional particles.

The invention further relates to a dust filter bag consisting of a nonwoven material, wherein functional particles, in particular activated carbon particles, adhere to the nonwoven material. Such dust filter bags are used in particular in vacuum cleaners, in particular electrically operated household vacuum cleaners.

In addition, the invention relates to a surface filter consisting of a nonwoven material, wherein functional particles, in particular activated carbon particles, adhere to the nonwoven material. Such surface filters are used in particular for particle filtration from air currents, more particularly when using such surface filter as a motor protection filter for vacuum cleaners, in particular electrically operated household vacuum cleaner.

In order to further improve a dust filter bag and / or surface filter of the type in question, it is proposed that the dust filter bag and / or the surface filter is manufactured by a method according to one or more of claims 1 to 7. Accordingly, the functional particles are in particular gas inlet side of the nonwoven material adhered to this according to a microscopic hot-bonding process, wherein preferably already heated to trigger the melting process functional particles or are introduced into the nonwoven material. Accordingly, the nonwoven material is preferably only selectively, especially in the immediate contact area of the functional particles fused, more particularly only in the region of isolated, adjusted to the impact temperature of the functional particles with respect to their melting temperature fibers. This results in a high and for the preferred filter properties sufficient air permeability of the filter produced from the nonwoven material even with a fusion of nonwoven material and functional particles. The filters made up in this way can also be cyclically cleaned with a reverse air flow without the functional particles losing their positioning relative to the nonwoven material.

With regard to additional or alternative features in connection with the subject inventions, such as dust filter bag and / or surface filters, the same applies as above with regard to the procedural features for their demanding assignment.

With regard to all specified ranges of values, all intermediate values, in particular in 1 mm and / or 1 degree Celsius and / or 1 percent increments, both in terms of a single or multiple narrowing of the specified range limits in, for example, the specified increment, from above and / or or from below, as well as to represent singular values within the stated ranges, are hereby included in the disclosure.

The invention is explained below with reference to the accompanying drawing, which, however, only an embodiment represents. On the drawing shows:

1 a plan view of a provided with functional particles nonwoven material, ready for production of a filter bag;

2 the method in a schematic representation for the attachment of the functional particles to the nonwoven material;

3 a greatly enlarged detail view of the area III in 2 ;

4 the top view according to arrow IV in 3 , but with functional particles reproduced in dotted line type;

5 the formed into a filter bag with the omission of a holding plate, with functional particles afflicted nonwoven material in a sectional view.

Shown and described is first with reference to 1 a spread nonwoven material 1 , in particular for producing a filter bag 2 , which is nonwoven material 1 represents the air-permeable filter bag wall.

The fleece material 1 indicates the use as a wall for a filter bag 2 an inflow side I and a downstream side II on which inflow side I Filter bag-inside is arranged.

On a limited area 3 the upstream side I are on the nonwoven material 1 functional particles 4 in particular to arrest activated carbon particles. The outside of the area 3 remaining, preferably circumferential edge of the nonwoven material 1 is used for seam welding of the material, and more preferably for welding the bag thus produced with a holding plate, not shown, and is therefore to keep free of particles.

The fleece material 1 preferably consists of different, more preferably multi-layered fibers, in particular synthetic fibers, wherein further over the thickness of the nonwoven material 1 considered different filter effects can be achieved. In this regard is on the DE 10 2004 046 669 A1 directed. The content of this patent application is hereby incorporated in full into the disclosure of the present invention, also for the purpose of including features of this patent application in claims of the present invention.

In particular facing the upstream side I are the surface side of the nonwoven material 1 fusible fibers 5 made of polyethylene or polypropylene, which are at least partially exposed on the surface side. These fibers 5 Depending on the choice of material, they have a melting temperature of 100 ° C to 180 ° C. Optionally adjacent fibers of other materials may have higher melting temperatures.

To arrest the functional particles 4 on the upstream surface of the nonwoven material 1 become the functional particles 4 first in a device 6 heated to a preferred temperature of 200 ° C to 250 ° C. This is above the melting temperature of the fibers 5 heated functional particles 4 For example, be over a non-woven material resting relative to the preferably on a support surface 1 movable chute 7 targeted by falling on the upstream surface of the nonwoven material 1 distributed (cf. 2 ). Depending on the height of fall of the functional particles 4 on the nonwoven material 1 and the duration between the heating of the functional particles 4 in the device 6 and hitting the nonwoven material 1 is the heating temperature of the functional particles 4 chosen so that an impact temperature of the functional particles 4 always above the melting temperature of the fibers 5 lies. A drop height of 100 mm is preferred at an ambient and non-woven temperature of 20 ° C. The functional particles 4 melt on contact with the fibers 5 this easily, so that the functional particles 4 stick after cooling (microscopic hot glueing process, see 3 ).

As in particular from the detailed representation in 4 can be seen, results with reference to a functional dot shown in phantom only in the illustration 4 a localized melting zone of the nonwoven material 1 , this in particular in the immediate area of contact with the functional particles 4 , This melting zone is preferably closed flat, more preferably selectively present, in any case, after cooling, the holding forces are large enough to the functional particles 4 on the nonwoven material 1 preferred to arrest permanently.

Further preferred are functional particles 4 in their number or in their distribution on the nonwoven material 1 chosen so that the upstream side surface, a total surface of the uninfluenced, that is not melted and thus continues to permeate air and correspondingly filter-active zones, the three to five times, preferably about four times that of the adhering functional particles 4 flow-tight zones corresponds. Thus, even at the nonwoven material 1 preferably permanently adhering functional particles 4 a good flow through the nonwoven material 1 Given appropriate good filter property.

5 shows the nonwoven material 1 after arrest of functional particles 4 on the upstream side I and after packaging into a filter bag 2 In the illustration, a possible holding plate is not shown.

All disclosed features are essential to the invention. The disclosure of the associated / attached priority documents (copy of the prior application) is hereby also incorporated in full in the disclosure of the application, also for the purpose of including features of these documents in claims of the present application. The subclaims characterize in their optional sibling version independent inventive development of the prior art, in particular to make on the basis of these claims divisional applications.

LIST OF REFERENCE NUMBERS

1

non-woven material

2

filter bag

3

area

4

functional particles

5

fibers

6

contraption

7

Schütte

I

inflow

II

outflow

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 102004046669 A1 [0030]

Claims (10)

Procedure for arresting functional particles ( 4 ), in particular activated carbon particles on a nonwoven material ( 1 ), wherein the arrest by a in the nonwoven material ( 1 ) heating of the functional particles ( 4 ) triggered melting process, characterized in that already heated to trigger the melting process functional particles ( 4 ) or in the nonwoven material ( 1 ) are introduced. A method according to claim 1 or in particular according thereto, characterized in that the nonwoven material ( 1 ) is not heated or heated only to a temperature at which the melting process is not yet triggered. Method according to one or more of the preceding claims or in particular according thereto, characterized in that the nonwoven material ( 1 ) contains fusible fiber components by heating. Method according to one or more of the preceding claims or in particular according thereto, characterized in that the fusible fibers ( 5 ) consist of polyethylene or polypropylene. Method according to one or more of the preceding claims or in particular according thereto, characterized in that the functional particles ( 4 ) are heated to a temperature of 120 ° C to 350 ° C. Method according to one or more of the preceding claims or in particular according thereto, characterized in that the functional particles ( 4 dropping from a height of 50 mm to 150 mm onto the nonwoven material ( 1 ) are applied. Method according to one or more of the preceding claims or in particular according thereto, characterized in that the functional particles ( 4 ) by an air flow on the nonwoven material ( 1 ) are applied. Method according to one or more of the preceding claims or in particular according thereto, characterized in that the functional particles ( 4 ) after application to the nonwoven material ( 1 ) are pressed. From a nonwoven material ( 1 ) existing dust filter bag ( 2 ), wherein on the nonwoven material ( 1 ) Functional particles ( 4 ), in particular particles of activated carbon, produced by a process according to one or more of claims 1 to 7. From a nonwoven material ( 1 ) existing surface filter, wherein at the nonwoven material ( 1 ) Functional particles ( 4 ), in particular particles of activated carbon, produced by a process according to one or more of claims 1 to 7.

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