WO1998029012A1

WO1998029012A1 - Cell for filling coverlets or the like

Info

Publication number: WO1998029012A1
Application number: PCT/EP1997/007323
Authority: WO
Inventors: Tobias Kirchhoff
Original assignee: Kirchhoff International Gmbh Münster
Priority date: 1996-12-31
Filing date: 1997-12-31
Publication date: 1998-07-09
Also published as: DE19654798A1; AU5860998A

Abstract

A cell of a cushion or quilt consists of an inner sheath (20) which encloses a cavity (16) and of an outer sheath (22) which encloses the inner sheath (20). The cell is closed by a seam (24) which extends through both sheaths. The inner sheath (20) is very air-permeable but substantially tight to small particles, such as allergens, with an order of magnitude from about 0.5 ν to about 3 ν. The outer sheath (22) is made of a light cotton fabric and is also highly permeable to air. The cell can be washed as a whole, i.e. with its filling (14), inner sheath (20) and outer sheath (22). The air throughflow resistance (RNL) of the seams is large in comparison with the sum of the air throughflow resistances (RJH, RAH) of the inner sheath (20) and outer sheath (22) which follow each other in the air flow direction.

Description

Cell construction for bed material and the like

description

5

The invention relates to a cell construction with a soft filling enclosed by a flexible, air-permeable covering system for bed components, pillows and play bodies, the soft filling being accommodated in a cell cavity within an inner covering made of fiber-containing, flexible, air-permeable and small particles retaining inner covering material, and wherein the Inner shell is accommodated within an outer shell made of flexible outer shell material with formation of seams. 5

Such a cell construction is known from EP 323 116 B1. It is also known (claim 7) to form an inner shell from a mite barrier material and to cover this inner shell with "usual material", which can basically be understood as an outer shell material. Due to the explanations in the European patent specification 323 116 B1, it can only be assumed that the covering material is the usual bedding, which is removed and washed regularly after short periods of use. 5

The mite barrier is defined in the patent specification as having a pore size of less than 10 μ. On the basis of this information, it is not to be expected that the so-called mite barriers can retain the excrement of house dust mites, which are primarily responsible for allergic complaints.

The invention is based on the object of specifying a cell construction which makes it possible to combat allergic symptoms in 5 allergy sufferers more effectively than before, without worsening the conforming properties of the cell construction. To solve this problem, the invention proposes that the inner shell material contains at least one fiber layer which, on the one hand, is highly permeable to air and, on the other hand, is highly active in capturing small particles with a particle size of approx. 0.5 μ to approx. 3 μ is that the inner shell in the outer shell is inseparably received by seams capturing both shells and is positioned against displacement even under washing conditions and that the resulting air flow resistance between the cell cavity and the surrounding atmosphere is set such that the pressure balance between the cell cavity and the surrounding atmosphere is essentially below complete avoidance of air flow through the seams takes place substantially entirely through the inner shell material.

The proposal of the invention achieves the following: In the selection of the inner shell material, one need only pay attention to high air permeability on the one hand and high particle trapping activity on the other hand and can look to others in the manufacture of bed components and the like. omit all or part of the necessary properties because these can be provided by the outer shell material, for example the mechanical structural strength required for longer use. Because the inner casing material and the outer casing material are positioned relative to one another by seams that grip both casings, there is also no risk of the uncontrollable displacement of the inner casing material within the outer casing material. If, for example, a pillow or a quilt of the cell construction according to the invention is smoothed or tapped by acting on the respective outer shell material, the sewing ensures that the inner shell material is also spread out accordingly. This effect becomes more apparent the smaller the individual cells are. The invention is therefore particularly suitable for use in quilts and small pillows where relatively small cells necessarily occur. The cells of the invention can also be washed in the washing machine without damage or destruction of the inner shell material occurs because it is protected by the outer shell material, so that even inner shell materials with very little structural stability can survive a large number of washing processes and can be brought back into position after drying by simply spreading the outer shell material again or tapping it flat. Sewing the inner shell material and outer shell material is therefore an essential aspect of the invention. At least in the case of quilts, the soft filler material will also be sewn in, so that it is and remains stable in the individual cells, without having to divide it into individual fillers during or before sewing. On the other hand, sewing is a very critical process with regard to fulfilling the task. When sewing, there are necessarily seam holes that can allow the small particles to pass through. There is a risk, in particular in the presence of long sewing distances, that small particles and in particular small particles of the size specified above are sucked into the cell on the one hand through the seam holes and on the other hand also ejected again. Consider the multiple deformations that the cells of a quilt suffer when used, but also when making beds and during other maintenance procedures. The volume of individual cells is occasionally greatly increased if they are approximated by deformation of the spherical shape and then greatly reduced again if they are approximated to a flat shape by crushing. These deformations are always accompanied by an exchange of air, and if this exchange of air takes place through the seam holes, there is a great risk that particles of the size defined above are then taken up or repelled by the cell at an inappropriate time. It has been recognized that this danger of suturing, which is advantageous for other reasons, as described above, can be avoided by adjusting the resulting air flow resistance between the cell cavity and the ambient atmosphere, in such a way that the pressure balance between the cell cavity is adjusted and ambient atmosphere takes place substantially completely through the inner shell material with substantially complete avoidance of air flow through the seams. If the specific air flow resistance per unit area of the inner shell material is greatly reduced, the air exchange through the inner shell material takes place essentially in the surface area of the inner shell material, and there are no significant flow threads in the area of seam stitches, which particles could carry in and out. For this reason, it is necessary to maintain the combination of properties of high air permeability and high particle trapping activity for the inner shell material. How this is achieved in detail will be described later.

It has already been indicated that the structural stability of the inner shell material can be reduced with regard to the presence of the outer shell material. This goes so far that the inner shell material can have a reduced structural stability, which requires protection by the outer shell in order to achieve the required long-term stability.

To avoid airflow through the stitching holes, it may be important to keep the air permeability of the outer shell material very large, ie to keep the air flow resistance of the outer shell material very low. It is therefore not easy to use the inlets customary in the bedding industry, which are produced with a relatively high material density, in particular in order to prevent the fiber material of the filling from escaping. Fortunately and surprisingly, the invention now provides a solution of its own accord: After the inner shell material counteracts high trapping activity against particle penetration, i.e. does not let particles pass through, not even particles in the order of magnitude of approx. 0.5 μ - approx. 3 μ, it is also effective for the retention of particles that are contained in the soft filling or are secreted there. For this Basically, there is no longer any need for the outer casing material to retain such soft filling particles, and as a result, when selecting the outer casing material, the aspect of restraining soft fill particles which is decisive in classic bedding manufacture can be neglected. This has the further consequence that, in spite of the cell structure with an inner shell material and an outer shell material, the overall material expenditure is not increased or only increased relatively little. This makes it possible to obtain cell constructions which, although impermeable to allergens, are comparable in their clinging properties to normal cell constructions and can also be offered at a comparable or only slightly increased price.

In line with the previous announcement, it should now be explained how the apparently contrary properties of the high air permeability on the one hand and the high particle trapping activity on the other hand of the inner shell material can be achieved.

One way of pairing these apparently contradictory properties is to form the inner shell material in one or more layers of relatively loose arrangement of the fibers. The more fibers lie on top of each other, the greater the likelihood of trapping particles, particularly if physical measures to be described mean that there is adhesion between fibers and particles as they fly by. Accordingly, if a large number of fibers lie on top of one another at each location of a surface element of the inner shell material, there is a high probability of trapping. On the other hand, the superimposition of the fibers of the inner shell material does not increase the air flow resistance to the same extent as the probability of trapping is increased if the fibers are relatively loosely one above the other. The molecules of the atmosphere are held back by the number of superimposed fibers in their path through the inner shell than the particles that are many orders of magnitude larger and must be retained.

An outstanding possibility for increasing the trapping activity of the inner casing material without simultaneously reducing the air permeability is that the trapping activity of the inner casing material is increased by applying an electrostatic charge, in particular by corona treatment of at least one component of the inner casing material. It has been shown that such a corona treatment can achieve high trapping activity even with a thin-layered inner shell material.

The corona discharge can be applied by guiding the entire inner shell material past an unloading station. However, it is also possible for individual layers which ultimately form the inner shell material, or at least one of them, to be or are guided separately past the corona unloading station. With regard to the implementation of the corona discharge, reference is made to the German-language translation of WO96 / 20833 given on pages 17-34 and to the secondary literature mentioned in WO96 / 20833.

It has proven to be advantageous if the inner shell material consists of at least one layer with active capture and at least one layer that increases stability. This distribution of the individual functions over individual layers makes it easier to determine the optimal structure of the inner shell material by simple preliminary tests. In these preliminary tests, one can proceed in particular by starting with a combination of a certain number of stability-increasing layers and a certain number of capture-active layers and then multiplying the respective number depending on the measurement result.

It is recommended that the inner shell material consists at least in part of synthetic fibers. Synthetic fibers have in the Usually a low conductance or, in other words, a high dielectric constant and are therefore suitable for maintaining a charge once it has been applied for as long as possible. For example, the inner shell material can consist at least partially of fibers which contain polyesters, polyolefins, polyamides or corresponding mixed polymers, preferably polypropylene fibers or mixed polymer fibers with a propylene content.

In the case of a multi-layer construction of the inner shell material, it is recommended that the inner shell material contains a spun-bond layer, in particular a spun-bond layer made of polypropylene or a mixed polymer with propylene content, as the stability-increasing layer, and that the inner shell material acts as a capture-active layer with a melt-blown layer. Layer, in particular a melt-blown layer made of polypropylene or copolymer with propylene content. For example, the inner shell material can consist of a spun-bond layer as a stability-increasing layer and a melt-blown layer as an active layer.

With regard to the term spun-bond layer, it suffices here first of all to indicate that a spun-bond layer can be obtained from a nozzle plate by continuous fiber extrusion, with or without stretching the fibers emerging from the nozzle bores. In this case, the fibers coming from the nozzle plate are struck on a layer-forming carrier which continuously runs along the downward gradient of the emerging fibers, the fibers being swirled by an air stream before they strike the layer-forming carrier. The speed at which these fibers strike the layer-forming carrier is set to a considerably greater value than it corresponds to the linear speed of the movement of the layer-forming carrier, so that the spun-bond fibers are ground and looped in an irregular manner on the layer-forming carrier surrender. The spun-bond fibers, for example thermoplastic fibers, can be bonded together Crossing points are fixed, for example by using any remaining thermoplastic or by remelting or by spraying on a solvent. The strength of the spun-bond fibers is usually not less than 1.5 dtex.

When producing a melt-blown layer, fibers are also obtained from a nozzle plate, these fibers being introduced into an air vortex zone. The resulting fibers have a diameter of <10 μ. These fibers are broken in the air vortices before they collect on a moving layer formation carrier. The length of the broken fibers is usually <10 mm. The fibers of the melt-blown layer can be connected to one another at intersections in a similar manner to the fibers of the spun-bond layer. In both cases, care must be taken to ensure that the air permeability is not too low or, in other words, the air flow resistance does not become too great by fixing the fibers of the individual layers.

It is also possible to staple the melt-blown layer together with the spun-bond layer, in which case welding, for example by ultrasound welding or detachment of individual fibers, can lead to the layers being connected. Of course, even with such connection technologies, care must be taken to maintain the low air flow resistance.

The corona treatment is preferably carried out on the possibly finished, possibly multi-layered inner shell material.

For details regarding the type of manufacture, fiber selection and corona treatment, reference is again made to PCT publication WO96 / 20833 and its translation attached on pages 17-34.

The outer shell material can, as a woven, knitted or as Fleece layer can be formed. In order to maintain the structural strength, it is recommended to use fabrics or knitted fabrics which, due to the binding technique, can be very loose and therefore highly permeable to air, without losing the required minimum of structural strength. With regard to the feel properties, natural fibers such as cotton fibers, in particular, are proposed for the outer shell material. Since, as already stated, the outer shell layer has essentially no significance with regard to the retention of small particles of the filling material and also does not have to fulfill an essential function with regard to the retention of small particles such as allergens, the outer shell material can be woven or knitted or otherwise tied relatively broadly, e.g. as a non-woven material so that it has high air permeability.

The seams that close the individual cells can basically be made in any way. Weld seams are in principle conceivable, but are less preferred, since if they are sufficiently durable they lead to noticeable and undesirable hardening of the cell or the respective bed component. Seams which are produced by piercing and therefore give rise to the risk of the formation of air flow threads in which small particles can be carried are preferred. In principle, it is conceivable to produce the seams using needle technology, such as is used for consolidating felt and nonwovens. Seams which are produced using the classic sewing technique with a needle and thread, for example by means of a sewing machine, are preferred; here, in turn, there is a risk of the formation of air flow threads, a risk that can be eliminated by the high air permeability of the inner shell material and the outer shell material.

A cell construction according to the invention, for example a pillow or a quilt, can be enclosed in a cover. This cover corresponds to the usual bed linen that is washed at short periodic intervals becomes. This bedding has inherently low air flow resistance and therefore hardly influences the outflow conditions from the respective cell. Otherwise, bed covers which are intended for frequent washing are generally only leak-tightly closed by buttons or the like, so that there are also air outlet possibilities here and consequently the air flow formation in pinholes in the envelope system is not significantly influenced.

The cover system according to the invention remains unchanged when changing the bed linen. The respective cell can be washed from time to time, for example at annual intervals. Since the shell system of the cell, consisting of the inner shell material and the outer shell material, cannot be removed in whole or in part, it is impossible to remove parts of the allergen-retaining shell system through negligence or on purpose, so that the impermeability to allergen particles is guaranteed in the long term.

It is also conceivable to fix the outer shell material and the inner shell material to one another at points where there are no cell boundaries to be formed. Care must be taken, however, that such connection technology does not create any additional pinholes in which allergenic air currents could occur.

For further details, reference is made to the content of the PCT publication WO96 / 20833, which is appended in the English and German text.

The soft filling can be formed from a cushion-like, voluminous synthetic nonwoven material, which can be easily sewn between two opposing areas of the envelope system by compacting the respective seam courses. Also suitable are cotton, kapok and washable animal hair fillings (virgin wool) and the like. In the sewing technique to be used, the number of needle stitches and the diameter of the needles used should be kept as small as possible.

The accompanying figures explain the invention using exemplary embodiments; it represents:

1 shows a quilt made with the cell construction according to the invention;

2 shows a small cushion designed as a cell construction according to the invention;

3 shows a game body designed as a cell construction according to the invention;

Fig. 4 is a section along line IV-IV of Fig. 3;

5 shows a section through an envelope system of a cell construction according to FIGS. 1 and

Fig. 6 is a circuit diagram of the air flow resistances.

In Fig. 1 you can see a quilt generally designated 10. This quilt comprises a plurality of cells 12. In the cells 12, a soft filling 14 made of padded synthetic fiber fleece is accommodated in each case. The material 14, in the following it is assumed that it is a material containing fibers, is located within a cavity 16 which is enclosed by a sheath system 18. The sleeve system 18 is composed of an inner sleeve 20 and an outer sleeve 22. The inner sleeve 20 and the outer sleeve 22 are sewn together by means of seams 24. The seams _24 penetrate the outer cover, the inner cover and the synthetic fiber fleece 14 lying in between. The individual layers of material can be seen in the section of Fig. 5. There the inner shell material is again designated with 20 and with 22 the outer shell material. The inner shell material 20 in turn has two layers and consists of a stabilizing spun-bond layer designated 20a and a highly air-permeable meltblown layer labeled 20b with high trapping activity for small particles, in particular small particles with a particle size of approximately 0.5 μ to approximately 3 μ. Solidification points can be provided within the spun bond layer 20a, which are designated by 30 and are formed, for example, by welding. Solidification points 32 can also be provided within the melt-blown layer 20b, for example by welding. It is also conceivable that the two layers 20a and 20b are bound to one another by continuous solidification points 34. The outer shell material 22 is formed, for example, by a knitted or woven cotton fabric, which lies loosely against the inner shell material 20 within the seams 24; but it can also be stitched to it point by point or line by line.

The total surface area of the inner shell material 20 surrounding the cell cavity 16 defines an air flow resistance R _ju ; the total surface area of the outer shell material 22 enclosing the cell cavity 16 defines an air flow resistance R _ω . The total length of the seams, ie the total of the seam stitches of the seams 24, defines an air flow resistance R _NL - the total surface of a duvet cover 36 defines an overall flow resistance R _BB .

FIG. 6 shows a circuit diagram in which the individual resistances are shown in terms of circuitry between the cell cavity 16 and the free atmosphere A. It is clear from Fig. 1 that the air flow resistance R _{JH of} the inner cover 20 and the air flow resistance R _{M of} the outer cover 22 are connected in series and that ^' the flow resistance R _{NL of} the seam stitch holes 24 parallel to the series connection of the air flow resistance R _{JH of} the inner cover 20 and the air flow flow resistance R ^ of the outer shell 22 is. It can also be seen from Fig. 1 that any noticeable air flow resistance R _{BB of} the duvet cover 36 is in series with the aforementioned parallel connection. All of this is shown in FIG. 6 in the manner of an electrical resistance circuit.

There is now a pressure difference ΔP between the cell cavity 16 and the atmosphere. This pressure difference brings about an air exchange between the cell cavity 16 and the atmosphere, for example as a result of cell compression by the compression forces shown in FIG. 1 and designated by K. It is essential, as can be seen from the above description, that the air flow through the seam stitch holes 24 is as small as possible. So that an air exchange s can nevertheless occur between the cell cavity 16 and the atmosphere A, the air flow must flow essentially through the inner shell material 20 and the outer shell material 22. This means that the air flow resistance R _{NL of} the seam stitch holes 24 must be large in relation to the sum of the flow resistances R _{JH of} the inner shell material 20 and R _{ω of} the outer shell material 22 after

Formula I: R ^,> R _m + R _ω . The flow resistance R _BB through the duvet cover material 36 can usually be neglected.

In other words, this formula should state the following: If - for example by flattening a blown-up cell - the air content of the cell is displaced to the outside, the majority of the air flow should take place through the entirety of the inner shell material and the outer shell material, while only a small part of the Total air exchange takes place through the seam holes. Air volumes that have penetrated the inner shell material and come to the seam holes between the inner shell material and the outer shell material have already been filtered and are therefore harmless, even if they continue their way out through the seam holes. It should also be borne in mind that - statistically speaking - not all particles have the same probability of escaping either through the seam or through the cover. The probability also depends on how far the particles are from the next seam hole. A particle that is approx. 2 mm away from a seam hole will in any case escape through the seam hole, no matter how permeable the cover is. A particle that is 5 - 10 cm away from the next seam hole will only make the "long way" if the cover is very dense, so that the detour is "worthwhile". However, if it emerges through the cover, it will escape near the original location, i.e. without an additional route.

Viewed macroscopically, an average drift resistance R _D must also be taken into account, which exists between a location within the cell and the closest seam area. This mean drift resistance can be thought of as being connected in series with the air flow resistance R _{NL of} the seam stitch holes, so that the still refined formula is then:

Formula II: R _NL + R _D R _JH + R _M.

The drift resistance is i.a. depending on the degree of filling, the filling density and the size of the respective cell.

For the structure of the stabilizing layer 20a made of spun-bond material and the active capture layer 20b made of melt-blown material and the outer shell 22, reference can be made to the explanations in the introduction to the description.

The structure of the quilt shown in FIG. 1 allows it to be washed in a washing machine without the risk of change or damage after removal of the duvet cover 36. As a rule, the duvet cover will be removed regularly after one or more weeks and washed separately. The quilt itself is removed after removing the duvet cover 36, for example Washed every year in the washing machine. There are padded nonwoven materials available that can withstand the washing process without changing the structure.

According to the circuit shown, both layers 20a and 20b of the inner shell material 20 must each have small values so that the sum of these values, represented by the resistance R _JH , remains small. The outer shell 22 should also have the lowest possible flow resistance. This is possible because - as already stated - thanks to the capturing activity of the inner shell 20, the outer shell 22 can consist of looser cotton fabric or knitted fabric without the particle permeability of the entire shell system 18 being increased.

2 shows a small pillow in the form of a single cell 212, which consists of an outer cover material 222, an inner cover material 220 and a filling 214 and is closed by an all-round seam 224 which engages in both covers 220 and 222. 2 applies to the behavior and the treatment of the pillow according to FIG. 2. If larger pillows are desired, it is advisable to manufacture them in quilted form, in the same way as in the case of the quilt according to FIG. 1.

3 shows a game body 312 in the shape of a heart. This game body is constructed in exactly the same way as the small pillow according to FIG. 2. Analog components are provided with the same reference numerals as in FIG. 2, each increased by the number 100.

3 and 4 apply to the behavior and the treatment of the toy body according to FIGS. 3 and 4.

In the sectional view of FIG. 5, the stabilizing layer 20a of the inner shell material 20 is remote from the outer shell material 22. It is also possible to use the stabilizing layer To allow layer 20a of the inner shell material 20 to bear directly against the outer shell material 22.

Multi-layer nonwoven laminate sheet

The present invention relates to a non-woven, multi-layer laminate web and to a "coverall" made from such a laminate web. In particular, the invention relates to protective clothing.

There are many types of protective clothing for temporary use or for single use disposal. These known garments are designed to have certain restraint properties. One type of protective clothing is designed as single-use protective clothing and is used in the U.S. Patent 4,670,913, which is intended to supplement the present disclosure and is therefore introduced here. Coveralls can be used to protect the wearer against dangerous environmental influences, such as open or sewage-tight protective clothing items cannot do. Accordingly, coveralls have many uses where isolation of a wearer is desirable.

Protective clothing should be resistant to liquids. For a variety of reasons, it is undesirable for liquids and / or pathogenic substances carried in liquids to pass through protective clothing and come into contact with persons who work in an environment containing pathogenic substances.

Furthermore, it is highly desirable to isolate people from harmful substances that may be present in a workplace or at an accident site. In order to increase the likelihood that protective clothing will be worn correctly and that this will reduce the chance of contact, the ^" respective worker should be aware of the possibility Make use of protective clothing that is relatively impervious to liquids and / or particles and that is also durable; this protective clothing should also be comfortable so that it does not restrict the activity of the worker. After use, it is often quite expensive to decontaminate protective clothing that has been exposed to a dangerous or harmful substance. It is important, therefore, that protective clothing is cheap and can possibly be thrown away.

Generally speaking, it is desirable that disposable protective clothing be made from fabrics that are relatively impervious to liquids and / or particles. These passage-inhibiting substances must also be suitable for the production of protective clothing at such a low cost that throwing away the protective clothing after one use is economically justifiable.

To establish a type of such disposable protective clothing that is usually made from non-woven laminate webs to the economics of the single-use is offered under the brand Kleenguard ^® Kimberly-Clark Corporation. These coveralls are made from three-layer, non-woven sheet laminate. The two outer layers are made of polypropylene fibers using the spunbond technique, and the inner layer is a meltblown layer made of microfine polypropylene fibers. The outer layers made using spunbond technology have a tough, durable and abrasion-resistant surface structure. The inner layer is not only water-repellent, but also acts as a breathable filter that allows air and water vapor to pass through while filtering out many harmful particles.

In some cases, the material used to make protective clothing will be made with a film layer or film laminate. Now you can in the production of Protective clothing with a film material to achieve improved particle penetration or, more precisely, particle retention properties, but it should be borne in mind that such film or laminate film-containing materials can also prevent the passage of air and moisture. In general, it can be said that protective clothing, which is made from such material, does not have enough air permeability and water vapor permeability and is therefore uncomfortable for long periods of use in terms of comfort.

While in some cases, film-lined or film-laminated liner materials can provide improved particle retention properties compared to nonwoven laminates, the nonwoven laminates provide greater comfort. There is therefore a need for a cheap, disposable protective clothing material, in particular made of non-woven fabric, which has improved particle retention properties, but is also breathable and is therefore comfortable for the wearer even with longer wearing times.

It is an object of the present invention to solve the problems outlined above and to meet the need for a nonwoven fabric with improved particle retention properties.

This goal is achieved by the multilayer, non-woven laminate web according to independent claim 1 and by the coverall construction according to independent claim 7.

The claims are to be understood as giving a non-limiting attempt to define the invention. Further advantageous properties, aspects and details of the invention result from the subclaims and the description.

In particular, the present invention is intended to relate to protective garments ^" made from non-woven fabrics with improved there are particle retention properties.

The present invention provides a nonwoven laminate web which is suitable for forming protective clothing, especially a coverall. According to one aspect of the invention, the nonwoven laminate web contains a layer of spun-bond fibers and a layer of meltblown fibers, at least one of these layers being subjected to a corona discharge. According to one embodiment, the layer formed from meltblown fibers has been subjected to the corona discharge.

In another aspect of the invention, the nonwoven laminate web of the present invention contains two layers of spunbond fibers. The two layers of spunbond fibers are separated from each other by a meltblown fiber layer. The nonwoven laminate sheet of this latter embodiment can be subjected to the corona discharge as a whole. However, it is also possible to subject the individual layers to corona discharge, e.g. the layer formed from meltblown fibers.

According to a further aspect of the invention, a protective garment in the form of a coverall is to be made from the multilayer, non-woven laminate web.

Embodiments that correspond to the above aspects provide improved particle filtration activities compared to similarly shaped nonwoven laminate webs that have not been subjected to corona discharge. In particular, the percentage improvement with regard to particle filtration activity in the corona discharge-treated, non-woven laminate webs for particles in the order of magnitude of 0.19 μ-0.3 μ is at least 85% greater compared to non-woven laminate webs which are not subjected to the corona discharge treatment have been. The percentage improvement in particle filtration activity of Corona discharge treated, nonwoven laminate webs in terms of particles in the order of 0.3 μ - 0.5 μ is at least 29%, based on nonwoven laminate webs not treated by corona discharge.

The improvements in particle filtration activity described above are achieved without the need to apply significantly higher charges to the surface or surfaces of the nonwoven laminate webs than was present before the corona discharge treatment.

When we speak of "nonwoven webs" in this specification, we mean webs that have a structure of single fibers or filaments, these fibers or filaments being laid across one another, but not in an identifiable, repetitive manner.

When further referred to as "spunbond fibers", this term refers to small diameter fibers formed by extrusion of molten thermoplastic material as filaments emerging from a plurality of fine, regularly circular capillary bores of a spinning plate are, the diameter of the extruded filaments is then suddenly reduced, for example according to U.S. Patent 4,340,563 to Appel et al. and according to U.S. Patent 3,692,618 to Dorschner et al. and according to U.S. Patent 3,802,817 to Matsuki et al. and according to U.S. Patents 3,338,992 and 3,341,394 to Kinney and the U.S. Patents 3,502,763 and 3,909,009 to Levy and the U.S. Patent 3,542,615 to Dobo et al. , which are hereby incorporated by reference into the disclosure. Spun-bond fibers are generally endless and have a diameter of more than 7 μm, in particular they have an average diameter of more than 10 μm.

The term "meltblown fibers" used further here is intended to identify fibers which are produced by extrusion of a melted thermoplastic material through a variety of fine, usually circular capillary nozzles as molten wires or filaments in a gas stream, for example high-speed air flow and usually high temperature, 5 are expelled so that the filaments are brought to a reduced diameter, which is up to a microfiber through - knife down. The meltblown fibers are then carried away by the gas stream at high speed and applied to a collecting surface in order to form a web of statically distributed meltblown fibers there. Meltblown fiber production is known in the prior art and is described, for example, in US Patent 3,849,241 by Buntin, in US Patent 4,307,143 by Meitner et al. and in U.S. Patent 4,707,398 to Wisneski et al; these patents are disclosed here as

15 support introduced. Meltblown fibers are microfibers which generally have a diameter of less than 10 μm.

If the expression “microfine fibers” or “microfibers” 20 is used here, fibers with a small diameter should be defined, the average diameter of which is not greater than 100 μ and which have a diameter of 0.5 μ-50 μ, for example. In particular, microfibers are meant which have an average diameter of approx. 1 μ to approx. 25 20 μ. Microfibers with an average diameter of approximately 3 μm and less are generally referred to as ultrafine microfibers. A description of an exemplary process for producing ultrafine microfibers can be found e.g. in U.S. U.S. Patent 5,213,881 which relates to a nonwoven web with improved capture properties. This document, too, is hereby to be introduced by naming it as a disclosure support.

Polymers are very suitable for forming nonwoven webs, namely those which are suitable for the application of the present invention. Nonwoven webs can be prepared by a variety of ^'procedures, including, but not limited to air laying processes, wet laying processes, hydraulic tangling processes, spun bonding, melt blowing, staple fiber carding and binding processes and solution spinning processes. The fibers forming such nonwoven webs can be made from a variety of dielectric materials, including, but not limited to, polyesters, polyolefins, nylon, and copolymers of these materials. The fibers can be relatively short staple fibers with a typical length of 7.62 cm, but also longer, possibly even endless fibers, as are obtained in spunbonding processes.

It has been found that nonwoven webs made from thermoplastic-based fibers and in particular polyolefin-based fibers are particularly suitable for the above-mentioned applications. Examples of such fibers include spunbond fibers and meltblown fibers. Examples of such nonwoven webs of fibers are nonwoven polypropylene webs manufactured by the patent owner Kimberley-Clark Corporation.

The invention includes a multi-layer, nonwoven laminate web. In one embodiment, the multi-layer nonwoven laminate web comprises at least one layer formed by spunbond fibers and another layer formed by meltblown fibers, ie a spunbond / meltblown based (SM) nonwoven laminate web. According to another embodiment, the multilayer, non-woven laminate web comprises at least one layer which is formed by meltblown fibers and which is interposed between two layers of spun-bond fibers. One speaks then of a spunbond / meltblown / spunbond laminate material (SMS). Examples of such nonwoven laminate webs are disclosed in US Patent 4,041,203 to Brock et al. , U.S. Patent 5,169,706 to Collier et al. , Bornslaeger U.S. Patent 4,374,888; these patents are introduced here as an additional basis for disclosure. The nonwoven laminate webs of the SMS type can be ^" manufactured by one after the other a moving forming belt is first applied with a spunbond layer, then a meltblown layer and then again with a spunbond layer, and then by fixing the laminate in the following manner. Alternatively, the layers can also be produced individually, wound up on rolls and then combined with one another in a separate connection process. Such laminates usually have a basis weight of approximately 300-400 g / m ² (gsm) corresponding to 0.1-12 ounces per square yard (osy) and in particular a basis weight of approximately 25-100 gsm corresponding to 0.75 to approximately 3 osy. Nonwoven multilayer laminates can generally be fixed in the course of their manufacture in order to give them sufficient structural integrity, ie the ability to withstand the stresses of further process steps up to the finished product. The fixation can be done in many different ways, for example by hydraulic confusion, needling, ultrasound fixation, adhesive fixation and thermal fixation.

Ultrasonic fixation is accomplished, for example, by letting the multilayer, nonwoven laminate web pass between a transducer and an anvil roll, as in U.S. Pat. Patent 4,374,888 by Bornslaeger.

Thermal bonding of nonwoven multilayer laminates can be achieved by passing them between the rolls of a calender. At least one of the rolls of the calender is heated, and at least one of the rolls, not necessarily the same as the heated one, has a pattern that is embossed into the laminate as it passes between the rolls. As the material passes between the rollers, it is subjected to both pressure and heat. The combination of heat and pressure, which is applied according to a certain pattern, results in the creation of melting zones in the multilayer laminate web, so that fixing points are created there, where the corresponding pattern points of the calender roll are located.

Various patterns of calender rolls have been developed. One example is the Hansen-Pennings pattern, which gives approximately 10-25% fixation area at approximately 15.5-77.5 fixation points per cm ² (100-500 fixation points per square inch), as described in U.S. Patent 3,855,046 to Hansen and Pennings. Another pattern that is frequently used is the so-called diamond pattern with periodically repeating and slightly offset diamond embossing points.

The exact calender temperature and pressure to fix the nonwoven multilayer laminate web depends on the thermoplastic compounds from which the nonwoven web is made. In general, the preferred temperatures for polyolefin-based nonwoven multilayer laminate webs are between 66 and 177 ° C (150 and 350 ° Fahrenheit) and the pressure is between 525 and 1750 N / cm (300-1000 pounds per linear inch) . In particular, in the case of polypropylene, the preferred temperature is between 132 and 160 ° C (270-320 ° Fahrenheit) and the pressure is between 700 and 1400 N / cm (400-800 pounds per linear inch).

Methods for corona discharge treatment of nonwoven webs are well known to those skilled in the art. In short, corona discharge is achieved by applying a sufficiently high voltage to an electrical field initiation structure (EFIS) near an electrical field receiving structure (EFRS). The voltage should be so high that ions are generated in the EFIS and flow from the EFIS to the EFRS. Both the EFIS and the EFRS are preferably made of conductive material. Suitable conductive materials are copper, tungsten, stainless steel and aluminum.

A particularly noteworthy technique of applying corona discharge technology to nonwoven webs is the process in accordance with U.S. Patent Application No. 07 / 958,958 dated October 9, 1992, which is owned by the University of Tennessee and is incorporated herein for the purpose of supplementing the disclosure. The technique described there provides that a nonwoven web is exposed to two fields of opposite polarity. Each of the electric fields leads to a corona discharge.

In those cases in which the non-woven web consists of several layers, the entire layering can be subjected to the corona discharge. In other cases, one or more individual layers, which are intended to form the nonwoven laminate web, or the fibers, which are intended to form such individual layers, can be subjected to the corona discharge separately and then connected to the other layers in a superimposed manner in order to form the nonwoven Form laminate web. In many cases - as will be demonstrated in the following examples in particular - the electrical charge on the nonwoven laminate before the corona discharge was approximately the same as after the corona discharge. In other words, the nonwoven laminate web did not always show a greater electrical charge after the corona treatment than before the corona treatment.

To demonstrate the peculiarities of the present invention, a polypropylene-based nonwoven SMS laminate web and a layer of polypropylene meltblown fibers were corona discharged as described in detail below. Among the tests performed on nonwoven webs, before and after each corona discharge, were two filtration tests. One of these filtration tests is commonly known as the NaCl filter activity test, hereinafter referred to as the "NaCl test". The NaCl test was carried out on an automated filter test device, which is a Certitest

(Trademark) model 8110 at TSI Inc., in St. Paul,

MN is available. ^" The particle filtration activity of each The substance tested is defined as a percentage, the number preceding the percentage sign being calculated using the formula 100 x (1-downstream particle / upstream particle)). The downstream particles represent the total number of particles that are introduced into the tester. The downstream particles are those particles which have been introduced into the tester and which have passed through the bulk of the substance to be tested. The tester determines the activity of a filter medium with an air flow that is supplied and that was approximately 32 1 / minute in the given measurement. The air stream contains a known amount of approximately 0.1 μ NaCl aerosol particles which are dispersed in it. At a flow rate of approximately 32 l of air per minute, the pressure drop is between 4 and 5 mm of water, measured between the state on the upstream side of the test substance and the state on the downstream side of the test substance.

The other particle filtration test is commonly known as the "BTTG test". The abbreviation "BTTG" stands for British Textile Technology Group based in Manchester, England. In general, the BTTG test is carried out in such a way that particulate material, for example talcum powder, is introduced into the air flow on the "challenge" side of the test substance by means of a blower. The blower not only directs the particulate air towards one side of the test fabric, but can also be adjusted so that a certain pressure drop, namely 5 mm water column, between the atmosphere on the challenge side of the test fabric and the atmosphere on the back of the test fabric arises. The concentrations of the dust particles in the challenge atmosphere and the dust particles in the backside atmosphere (ie the particles that have passed through the test substance) are counted in different size ranges using a particle counter. The filtration activity of the test substance for a certain particle size range is defined in percent, the percentage before the percent sign being obtained after Formula 100 x (1 - (challenge-side particle sizes / rear particle sizes)). The challenge-side particles represent the total number of particles of different sizes that were introduced into the airflow on the challenge side of the test substance. The backside particles represent the number of challenge-side particles of various sizes that have passed through the bulk of the test fabric.

Example I

In example I, a nonwoven polypropylene-based laminate web of the SMS type with a basis weight of 61 g / m ² (1.8 osy) was produced. The spunbond layers were formed from polypropylene resins from Exxon with the designations PD-3445 and Himont PF-301. White and dark blue pigments, namely Ampacet 41438 (manufacturer Ampacet Inc., NY) and SCC 4402 (Standige Inc., GA) were added to the polypropylene resins which formed one of the spunbond layers. The other of the spunbond layers was made from these polypropylene resins while avoiding the pigment addition. The meltblown layer was made from Himont PF-015 polypropylene resin without pigments.

The meltblown layer had an average basis weight of approximately 15.3 g / m ² (approximately 0.45 osy), and each of the spunbond layers had an average basis weight of approximately 22.9 g / m ² (approximately 0.675 osy). A piece of this 61 g / m ² ESM material was subjected to a corona discharge (SMS-CD). Corona discharge was generated using a Model No. P / N 25A - 120 volt, 50/60 Hz reversible polarity voltage source (manufacturer Simco Corp., Hatfield, PA) connected to the EFRS. The EFIS was an RC-3 charge master with a charging bar (manufacturer Simco. Corp.); the EFRS was a rigid aluminum roller approximately 7.62 cm (3 inches) in diameter. The ambient atmosphere of the corona discharge was around 21 ° C (70 ° booklet) and 40% relative humidity. poses. As described in the University of Tennessee patent application mentioned above, two groups of EFIS / EFRS are used. The voltage applied to the first group of EFIS / EFRS was 15 KV / 0.0 V, the voltage applied to the second group of EFIS / EFRS was 25 KV / 7.5 KV. The gap between the EFIS and EFRS was 2.54 cm (1 inch).

Particle filtration activity was determined using the BTTG test, once using the SMS nonwoven laminate web with a unit weight of 61 g / m ² (1.8 osy) which had been subjected to corona discharge (SMS-CD). and on the other hand using a nonwoven laminate web again of the type SMS and the unit weight 61 g / m ² (1.8 osy), which had not been exposed to the corona discharge SMS. The results are shown in Table I below.

Table I Particle Filtration Activity (%) Particle Sizes (µm)

.19-.3 .3-.5 .5-1 1-3 3-5

Fil material

SMS-CD 76.5 89.4 96.4 98.2 97.6 SMS 41.3 68.1 84.4 92.1 94.8

Example II

According to Example II, a polypropylene-based nonwoven laminate web of the SMS type was produced with a unit weight of approximately 61 g / m ² (1.8 osy). The unit area weights of the meltblown layer and the spunbond layers were the same as in Example I. When producing part of the nonwoven SMS material, however, this time the meltblown layer was subjected to a corona discharge and then combined with the spunbond layers. The corona discharge was produced under essentially the same conditions and in ^"using the same material and insurance search structure, as described in Example I.

Particle filtration activity was determined using the BTTG test, both for the 61 g / m ² basis weight nonwoven laminate web of the SMS type, which was produced using the meltblown layer with corona discharge treatment (SMS-MCD) , as well as using the nonwoven laminate web of the SMS type with a unit weight of 61 g / m ² , which was not exposed to the corona discharge treatment (SMS). The results are shown in Table II.

Table II Particle Filtration Activity (%) Particle Sizes (µm)

.19-.3 .3-.5 .5-1 1-3 3-5

Filter material

SMS-MCD 58.5 84.9 94.1 97.5 98.3 SMS 21.7 65.6 83.9 94.2 96.9

The values of both Examples I and II show the improved particle filtration activity and in particular the improved particle filtration activity for particles in the size range between 0.19 μ and 0.5 μ which results as a result of the corona discharge treatment, be it that the entire nonwoven laminate material or even just one of the layers thereof is subjected to this corona discharge treatment.

As for Example I, the percentage improvement in particle filtration activity of the corona discharge treated SMS materials (SMS-CD) for particles in the order of 0.19 μ to 0.3 μ is approximately 85.2% compared to materials that are not corona Have been subjected to discharge treatment (SMS). The percentage improvement in particle filtration activity of SMS-CD material for particles in the order of 0.3 μ - 0.5 μ was compared to SMS material approximately 31.3%.

As for Example II, the percentage improvement in particle filtration activity for the SMS material formed from corona discharge treated meltblown (SMS-MCD) was 169.6% for particle sizes between 0.19μ and 0.3μ compared to non-corona discharge treated SMS (SMS). The percentage improvement in particle filtration effectiveness of SMS-MCD material for particles in the size order of 0.3 μ - 0.5 μ was approximately 29.4% compared to SMS material.

Example III

According to Example II, three nonwoven laminate webs of the SMS type were made on the basis of polypropylene, each with a unit weight of 61 g / m ² on the basis of polypropylene, each of these samples being produced from meltblown layers and spunbond layers of the same unit weight as in Example I was described for the SMS material there.

Particle filtration activity using the NaCl test for a portion of each of the SMS samples of Example III was determined. The surface charge of an SMS sample (SMS) was determined which was not subjected to a corona discharge. The surface charge of another SMS sample which had been subjected to a corona discharge (SMS-CD) was also determined after the corona discharge treatment had been carried out. Finally, the third SMS sample was prepared by first subjecting the meltblown layer to a corona discharge treatment and then combining it with the spunbond layers (SMS-MCD). The surface tensions for each side of the SMS samples so formed were measured using an electrostatic voltmeter

(Trek Model 344, Trek, Inc., Median, NY), with the mean of at least ten readings on each side of the Samples was formed.

The corona discharge for SMS-CD and the corona discharge for SMS-MCD were generated under essentially the same conditions, further using essentially the same equipment and using the essentially same experimental set-up as described in Example I. The results are shown in Table III below.

Table III

Corona discharge side A / B (volt) Filtration activity (%)

Filter material SMS No -123 / + 63 33.6

SMS-MCD Yes + 85 / -14 71.4

SMS CD Yes + 38 / + 80 88.2

Example III shows that the improved particle filtration activity is achieved when the SMS material is subjected to corona discharge without the need to generate a significantly higher charge on the surface or surfaces than previously when the corona was not used - Discharge treatment was generated. In fact, the difference between the surface charge of the SMS material before and after the corona discharge treatment is minimal at most.

The invention has been described in detail with reference to certain embodiments.

It is clear to the person skilled in the art after understanding the above explanations that modifications, variations and equivalents of the above-described exemplary embodiments are possible. Therefore, the scope of the invention should not be limited to the details of the following claims, but should at least include the equivalents.

1. A multilayer, nonwoven laminate web comprising: at least one layer formed by spunbond fibers and a further layer formed by meltblown fibers, the fibers having been subjected to at least one of these layers to a corona discharge; wherein the multilayer, nonwoven laminate web has a percentage improvement in particle filtration activity for particles with a size range of 0.3 μ - 0.5 μ of at least 29% compared to similarly constructed nonwoven multilayer laminate webs which have not been subjected to such a corona treatment.

2. The nonwoven multi-layer laminate web of claim 1 comprising: at least two layers formed from spunbond fibers and at least one layer formed from meltblown fibers, the layer formed from meltblown fibers the two of spunbond fibers separated layers separated.

3. The nonwoven multilayer laminate web of claim 1 or 2, in which the spunbond fibers and the meltblown fibers are polypropylene fibers.

4. The multilayer nonwoven laminate web of any of the preceding claims, wherein the average basis weight of the nonwoven laminate web is approximately 61 g / m ² (approximately 1.8 ounces per square yard).

5. The nonwoven multi-layer laminate web of any of the preceding claims, wherein the average unit area weight of the layer formed from meltblown fibers is approximately 15 g / m ² (approximately 0.45 ounces per square yard).

6. The nonwoven multilayer laminate web according to any one of the preceding claims, wherein the meltblown fibers have been subjected to corona discharge. 7. A coverall garment made from the nonwoven multi-layer laminate web of any of claims 1-6.

8. The coverall garment according to claim 7, which is designed as a protective garment.

Claims

claims

1. Cell construction with a soft filling (14) enclosed by a flexible, air-permeable covering system (18) for bed components (10), small pillows (212) and play body (312), the soft filling (14) in a cell cavity (16) inside an inner shell produced with a seam formation (24) made of a fibrous, flexible, air-permeable and small particle-retaining inner shell material (20), and wherein the inner shell (20) is accommodated within an outer shell (22) made of flexible outer shell material with seam formation that the inner shell material (20) contains at least one fiber layer (20a, 20b), which on the one hand is highly permeable to air and on the other hand is highly capture-active for small particles with a particle size of approx. 0.5 μ to approx. 3 μ that the seams (24) in the outer shell (22) through both shells (20,22) seizing seams (24) inseparable and is positioned against shifting even under washing conditions and that the resulting air flow resistance between the cell cavity and the surrounding atmosphere is set such that the pressure equalization between the cell cavity (16) and the surrounding atmosphere (A) while largely avoiding air flow through the seams (24) largely through the inner shell material (20).

2. Cell construction according to claim 1, characterized in that the inner shell material (20) has a reduced structural stability, which to achieve the required long-term stability of protection by Outer shell (22) is required.

Cell construction according to claim 1 or 2, characterized in that the outer shell material (22) has a small particle permeability which requires the soft lining (14) of the inner lining through the inner shell material (20) to achieve a required tightness against the escape of small particles.

4. Cell construction according to one of claims 1-3, characterized in that the trapping activity of the inner shell material (20) is increased by electrostatic charging, in particular by corona treatment of at least one component (20a, 20b) of the inner shell material (20).

5. Cell construction according to one of claims 1-4, characterized in that the inner shell material (20) consists of at least one capture active layer (20b) and at least one stability-increasing layer (20a).

6. Cell construction according to one of claims 1-5, characterized in that the inner shell material (20) consists at least in part of synthetic fiber.

7. Cell construction according to one of claims 1-6, characterized in that the inner shell material (20) consists at least in part, preferably in total, of dielectric material.

8. Cell construction according to one of claims 1-6, characterized in that the inner shell material (20) at least partially Fibers exist which contain polyesters, polyolefins, polyamides or corresponding mixed polymers, preferably polypropylene fibers or mixed polymer fibers with propylene content.

9. Cell construction according to one of claims 1-8, characterized in that the inner shell material (20) as a stability-enhancing layer a spun-bond layer (20a), in particular a spun-bond layer (20a) made of polypropylene or a copolymer with Contains propylene.

10. Cell construction according to one of claims 1-9, 15 characterized in that the inner shell material (20) as a capture-active layer, a melt-blown layer (20b), in particular a melt-blown layer (20b) made of polypropylene or copolymer with propylene content , contains.

20th

11. Cell structure according to one of claims 1-10, characterized in that the inner shell material (20) consists of at least one spun-bond layer (20a) as a stability-increasing layer 25 and at least one melt-blown layer (20b) as an active capture layer .

12. Cell construction according to one of claims 1-11, characterized in

30 that the inner shell material (20) is solidified at least in the region of individual layers (20a, 20b) by fixing at least some of the fiber crossing points (at 30 or 32).

35 13. Cell construction according to one of claims 1-12, characterized in that the inner shell material (20) by mutual Ver stitching (at 34) of individual layers (20a, 20b), in particular punctiform or linear stitching, is solidified.

5 14. Cell structure according to one of claims 1-13, characterized in that the outer shell material (22) is designed as a woven, knitted or non-woven layer.

ιo

15. Cell structure according to one of claims 1-14, characterized in that the outer shell material (22) consists at least in part of natural fiber, in particular cotton fiber.

15 16. Cell construction according to one of claims 1-15, characterized in that the air flow resistance (R _M ) of the outer shell material (22) is substantially smaller than the air flow resistance (R _JH ) of the inner shell material (20).

20th

17. Cell structure according to one of claims 1-16, characterized in that the seams (24) are made as thread seams, which the inner shell material (20), the outer shell material 25 rial (22) and, if desired, also the soft filling material (14) enforce in whole or in part.

18. Cell construction according to one of claims 1-17, characterized in

30 that it is at least partially enclosed by a cover (36).

19. Cell construction according to claim 18, characterized in

35 that the cover (36) is closed by an air exchange-enabling closure technique, which is an easy and ^" if necessary multiple changes of Cover (36) allowed.

20. Cell construction according to one of claims 1-19, characterized in that the soft filling (14) consists of a cushion-like voluminous synthetic fleece material, or cotton, or Kapok, or washable animal hair material (new wool).