Classifications

• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/54—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving
  • D04H1/56—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving in association with fibre formation, e.g. immediately following extrusion of staple fibres
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/42—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
  • D04H1/4282—Addition polymers
  • D04H1/4291—Olefin series
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H3/00—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length
  • D04H3/005—Synthetic yarns or filaments
  • D04H3/007—Addition polymers
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H3/00—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length
  • D04H3/08—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length characterised by the method of strengthening or consolidating
  • D04H3/16—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length characterised by the method of strengthening or consolidating with bonds between thermoplastic filaments produced in association with filament formation, e.g. immediately following extrusion
• • D—TEXTILES; PAPER
  • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B2321/00—Fibres made from polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D10B2321/02—Fibres made from polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds polyolefins
  • D10B2321/022—Fibres made from polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds polyolefins polypropylene

Definitions

• the present invention relates to a tempered meltblown nonwoven fabric with high compressive strength and in particular a tempered voluminous meltblown nonwoven fabric with high compression hardness.
• the present invention relates to a method of making such a tempered meltblown nonwoven fabric.
• the production of felts and nonwovens from staple fibers and / or continuous filaments usually takes place by means of known mechanical or aerodynamic methods.
• a known aerodynamic process is the meltblown process according to the Exxon principle, as described for example in US Pat. No. 3,755,527. In this process, a low viscosity polymer is extruded through capillaries located at a nozzle tip.
• the forming polymer droplets are then acted upon from two sides with a called air blast, having a high temperature and velocity, air flow, as a result of which the polymer droplets are pulled out to a PoEymerkastrahl in the form of fine filaments.
• a vibration process is also induced in the free jet in the free jet, as a result of which high-frequency processes occur which accelerate the polymer strands beyond the speed of the blast air.
• the polymer strands are additionally stretched, so that the filaments obtained after depositing the filaments on a support and after cooling can have a diameter and a fineness in the single-digit micrometer range or even less.
• the so-called meltblown nonwovens or meltblown nonwovens are used for different applications, such as for example Refunctions in the hygiene sector. For these applications, the filaments are deposited on the support as a flat, two-dimensional nonwoven fabric.
• the nonwoven webs For some nonwoven applications, such as their use as acoustic damping materials, the nonwoven webs must be bulky, ie, have a large internal void volume.
• a major disadvantage of the known voluminous meltblown nonwovens is their relatively low stiffness and the resulting low compressive strength, especially at higher loads. Furthermore, these materials are usually limp, which means that they already deform under their own weight but retain no particular shape. For these reasons, these known meltblown nonwovens and in particular known voluminous meltblown nonwovens are difficult to permanently convert into a predetermined shape. Deformation usually results in addition to a compression of these nonwovens.
• the object of the present invention is therefore to provide a voluminous meltblown nonwoven fabric which has an increased rigidity and in particular an increased compression hardness, especially at relatively high loads, which also maintains its thickness-specific acoustic properties, such as the degree of acoustic absorption, and which also easily to transfer a predetermined permanent shape is.
• this object is achieved by a tempered meltblown nonwoven obtainable by a process in which at least part of the meltblown VEiesstoffs is subsequently annealed at a temperature between the glass transition temperature and 0.1 ° C below the melting temperature of the filaments
• the meltblown nonwoven fabric has a basis weight of 100 to 600 g / m 2 , a density of 5 to 50 kg / m 3 and preferably a compression hardness measured according to DIN EN ISO 3386 at 60% compression of at least 2 kPa.
• the voluminous meltblown nonwoven fabric according to the invention is also characterized by a significantly increased compression hardness, especially at higher loads, such as 40% or 60% compression, namely by a compression hardness of 60% compression of at least 2 kPa. Such high compression hardnesses can not be achieved for such voluminous meltblown nonwoven fabrics without tempering.
• the voluminous meltblown nonwoven fabric of the invention can be easily formed into a desired shape during tempering.
• these advantages are at least partly due to the fact that in the tempering according to the invention carried out subsequently, the degree of crystallization of the nonwoven filaments, which are predominantly amorphous, is significantly increased. This is presumed because the inventors have found that the melting temperature of the filaments of the meltblown nonwoven fabric may increase by about 10 to 20 ° C due to the tempering depending on the conditions during annealing.
• the experiments carried out by the inventors seem to show that the very high withdrawal speeds in the production of the filaments to very thin filaments, it comes to a rapid cooling of the polymer melt despite the hot blast air, whereby the amorphous molecular structure of the melt to a certain extent "frozen
• the degree of crystallization of the amorphous nonwoven filaments is increased by the tempering according to the invention
• the filament fineness and the nonwoven structure are not or at least negligibly changed by the tempering, so that the voluminous nonwoven fabric after tempering has its other properties, namely its thickness-specific acoustic properties Properties, such as acoustic absorption, maintains.
• meltblown nonwoven fabric is understood as meaning a nonwoven fabric produced by one of the known meltblown processes. depending on whether it is a flat 2-dimensional non-woven fabric or a voluminous non-woven fabric. Processes for producing such meltblown nonwoven fabrics are described, for example, in US Pat. No. 4,118,531, in US Pat. No. 4,375,446, in US Pat. No. 4,380,570 and in DE 1785712 C3.
• annealing generally means a heat treatment, ie heating the meltblown nonwoven fabric at the aforementioned temperature for a certain period of time.
• at least part of the meltblown nonwoven fabric is subsequently tempered, namely at a temperature which lies between the glass transition temperature and 0.1 ° C.
• the annealing can for example be carried out so that the meltblown nonwoven fabric is first annealed at a temperature of 150 ° C, after a certain period of example, for example 10 minutes the temperature to 155 ° C (the 2 ° C is below the melting temperature, which have the filaments of the meltblown nonwoven fabric at this time) is increased, after a further period of example, again for 10 minutes, the temperature to 165 ° C (the 2 ° C below the melting temperature
• meltblown nonwoven fabric is annealed in sections or over the entire surface.
• a certain subregion of the meltblown nonwoven fabric or several subregions of the meltblown nonwoven fabric can be tempered, whereas the remainder of the meltblown nonwoven fabric remains unannealed. It is also possible and particularly preferred according to the present invention, to anneal the entire meltblown nonwoven fabric.
• meltbnoven nonwoven fabric or the part (s) to be annealed at a temperature is tempered / which is between 20 ° C below the melting temperature and 0.1 ° C below the melting temperature of the filaments of the meltblown nonwoven fabric.
• the heat treatment is particularly preferably carried out at a temperature which is very particularly preferably between 15 ° C. below the melting temperature and 1 ° C. below the melting temperature, more preferably between 10 ° C. below the melting temperature and 0.1 ° C.
• the melting temperature between 5 ° C below the melting temperature and 0.1 ° C below the melting temperature, such as at about 5 ° C below the melting temperature (ie, for example, between 8 ° C below the melting temperature and 2 ° C below the melting temperature), and most preferably between 2 ° C below the melting temperature and 1 ° C below the melting temperature of the filaments of meltblown nonwoven fabric
• the duration of tempering depends on the temperature to which the meltblown nonwoven fabric is heated during tempering, where a lower tempering temperature tends to require a longer annealing time.
• the annealing time is 2 minutes to 2 hours, more preferably 2 to 60 minutes, and most preferably 2 to 10 minutes.
• the meltblown nonwoven fabric is tempered for 2 minutes to 2 hours at a temperature which is between 20 ° C below the melting temperature and 1 ° C below the melting temperature of the filaments of meltblown nonwoven fabric. More preferably, the annealing of the meltblown nonwoven fabric is carried out for 2 to 60 minutes at a temperature which is between 15 ° C below the melting temperature and 2 ° C below the melting temperature of the filaments of the meltblown nonwoven fabric, and most preferably the annealing of the Meltblown nonwoven fabric is carried out for 2 to 10 minutes at a temperature which is about 5 ° C below the melting temperature, ie between 8 ° C below the melting temperature and 2 ° C below the melting temperature of the filaments of Meltbiown nonwoven fabric.
• the melting point of the meltblown nonwoven fabric during annealing may increase due to the increase in the degree of crystallinity.
• the distance between the annealing temperature and the melting point of the meltblown nonwoven fabric during tempering would increase more and more and thus the required tempering time would be comparatively long.
• the temperature during the annealing to keep the annealing temperature always just below (for example, about 2 ° C or 5 ° C) below the melting point of the meltblown nonwoven fabric which increases during annealing .
• the melting temperature of the filaments of the meltblown nonwoven fabric prior to annealing is 152 ° C
• the melting temperature of the filaments of the meltblown nonwoven fabric increases to 170 ° C during tempering
• Annealing as set forth above, for example, be carried out so that the meltblown nonwoven fabric is first annealed at a temperature of 150 ° C, after a certain period of example, for 10 minutes the temperature to 155 ° C (which is 2 ° C below the melting temperature having the filaments of the meltblown nonwoven fabric at this time) is raised, after another period of, for example, another 10 minutes, the temperature to 165 ° C (which is 2 ° C below the melting temperature, which the filaments of
• the present invention is not limited in the way the meltblown nonwoven fabric is tempered.
• annealing has proven to be not only simple, but particularly effective, in which the meltblown nonwoven fabric is exposed to hot air and / or superheated steam.
• the hot air or the superheated steam has a temperature which corresponds to that at which the meltblown nonwoven fabric is heated during the tempering.
• Hot melt air or superheated steam is preferably applied to the meltblown nonwoven fabric in this embodiment by flowing around the meltblown nonwoven fabric with the hot air or with superheated steam or, more preferably, flowing through it.
• the meltblown nonwoven fabric is preferably tempered in an oven which has at least one blow box which is arranged so that the hot air or superheated steam can be blown into the meltblown nonwoven fabric.
• the blow box is to be designed such that the hot air or superheated steam is blown only into the part (s) of the meltblown nonwoven fabric to be tempered.
• the Meltbtown-Viiesstoff is annealed in an oven having at least one suction box, which is arranged so that the meltblown nonwoven fabric flowing through air or superheated steam can be sucked to a safe To ensure flow.
• the meltblown nonwoven fabric is tempered in an oven having at least one blow box and at least one suction box, wherein the at least one blow box is arranged so that the hot air or superheated steam in the meltblown Nonwoven fabric can be injected, and, wherein the at least one suction box is arranged so that the air flowing through the meltblown nonwoven fabric or superheated steam can be sucked off.
• the furnace comprises two blow boxes and one or two suction boxes, the suction box being located downstream of the first or second blow box in the case of a suction box and, in the case of two suction boxes, the two suction boxes downstream of the first and second Blaskastens are arranged.
• the meltblown nonwoven fabric has a weight per unit area of 100 to 600 g / m 2 . Particularly good results are obtained, in particular with regard to the acoustic properties of the nonwoven, when the basis weight of the meltblown nonwoven fabric is 150 to 400 g / m 2 , more preferably 200 to 400 g / m 2 and most preferably 250 to 350 g / m 2 about 350 g / m 2 , is.
• the meltblown nonwoven fabric is a voluminous meltblown nonwoven fabric having a te from 7 to 40 kg / m 3 , more preferably from 8 to 25 kg / m 3 and particularly preferably from 10 to 20 kg / m 3 .
• the filaments of the stitchblown nonwoven fabric may consist of any polymer which has a melting point suitable for extrusion and a melt viscosity sufficiently low for the meltblown process, for example polyolefins, polyamides, polyester esters, polyphenylene sulfides, polytetrafluoroethylene or a polyether ether ketone , Examples of polyesters are polyethylene terephthalate and polybutylene terephthalate. In particular, filaments of polysilicon and more preferably of polypropylene and / or polyethylene have proved to be particularly suitable.
• the filaments of the meltblown nonwoven fabric according to the present invention are composed of isotactic polypropylene because it has been found that with isotactic polypropylene filaments, the degree of crystallization during the annealing is particularly well increased.
• the thickness of the meltblown nonwoven fabric is preferably 6 to 50 mm, more preferably 8 to 40 mm, most preferably 10 to 30 mm, and most preferably 15 to 25 mm, in particular about 20 mm.
• meltblown solid in a shaped body in order to convert the meltblown nonwoven fabric during the tempering in a predetermined shape. This can be achieved, for example, by forming the shaped body in which the meltblown nonwoven fabric is tempered, at least partially as a sieve that the meltblown nonwoven fabric can be flowed through during the annealing with hot air or superheated steam and / or can flow around it.
• meltblown nonwoven fabric after heating, but before cooling into a shaped body and thus to convert it into a predetermined shape in order to reform it, wherein the meltblown nonwoven fabric is cooled in the mold to complete the annealing process .
• the meltblown nonwoven fabric can be formed by the annealing as a stamped part in a certain shape, such as in a hemisphere.
• the tempered and shaped meltblown nonwoven fabric is significantly more dimensionally stable than the starting material and retains its shape as much as possible. Accordingly, the meltblown nonwoven fabric can take over after tempering forces, so that can be dispensed with after molding on additional stiffening structural elements in the meltblown nonwoven fabric.
• At least one spacer arranged in the thickness of the meltblown nonwoven fabric and having a length which is greater than the thickness of the meltblown nonwoven fabric is provided in the meltblown nonwoven fabric. This is advantageous, for example, when the meltblown nonwoven fabric is to be used as an acoustic absorber.
• an intrinsically rigid molded article is obtained in which by virtue of the spacer (s) - when acting as an acoustic absorber in front of a reflective plane, such as the bending wall an automobile, is mounted - a not insignificant air gap is formed between the absorber and the reflecting plane, wherein the thus created additional air volume acts as an integral part of the absorber structure.
• a reflective plane such as the bending wall an automobile
• the thus created additional air volume acts as an integral part of the absorber structure.
• the above-described volume of air between the absorber and the wall can also be provided by a wall structure with a planar absorber or a structure of the wall and the absorber, with the intrinsic stiffness of the absorber being required for the permanent formation of the air volume.
• the meltblown nonwoven fabric to be annealed may be made by any of the known meltblown processes, such as those described in US 4,118,531, US 4,375,446, US 4,380,570, or DE 1785 712 C3.
• meltblown process nonwoven fabric is produced by supplying air flowing through a nozzle extruded polymer melt on the outside and drawing it before the filaments formed thereby are deposited on a support and cooled.
• the carrier is preferably a double suction drum.
• annealing increases the degree of crystallization of the meltblown nonwoven fabric.
• the filaments of the tempered meltblown nonwoven fabric at least in sections and preferably over the entire surface have a degree of crystallization of from 20 to 80%, more preferably from 30 to 75%, more preferably from 40 to 75% and most preferably from 50 to 70%.
• the annealed areas of the tempered meltblown nonwoven fabric preferably have a crystallization degree of from 20 to 80%, more preferably from 30 to 75%, particularly preferably from 40 to 75% and most preferably 50 up to 70%.
• the meltblown fiber has, at least in sections and preferably over the entire surface, a compression hardness measured according to DIN EN ISO 3386 (compression stress) at 60% compression of at least 2 kPa.
• the meltblown nonwoven fabric particularly preferably has, at least in sections and preferably completely, a compression hardness measured at 60% compression of at least 4 kPa, more preferably of at least 6 kPa, even more preferably of at least 8 kPa, based on DIN EN ISO 3386, even more preferably of at least 10 kPa, even more preferably of at least 12 kPa, even more preferably of at least 15 kPa, very particularly preferably of at least 20 kPa and most preferably of at least 30 kPa.
• the required compressive stress is to be understood, under which a material sample undergoes a reduction in thickness by 60% of the initial thickness. Furthermore, the preload for determining the initial thickness of the material is reduced to 0.014 kPa to account for the very low compressive strength of the untempered material. Deviating compression levels or other test conditions may result in different compressive stresses with non-linear relationships to the stated values.
• the inventive concept In order to shorten the annealing time, it is proposed in a further development of the inventive concept to continuously or stepwise raise the annealing temperature in the annealing, preferably also beyond the melting temperature of the untempered filaments of the meltblowrv nonwoven fabric, but always at least 0.1 ° C is below the current (ie, the present at this time melting temperature) of the filaments of meltblown nonwoven fabric.
• the present invention makes it possible to increase the degree of crystallization of the filaments of meltblown nonwoven fabrics in sections or over the entire surface and thus to increase the rigidity of meltblown nonwoven fabrics in sections or over the entire surface.
• the present invention can be used to anneal the Meitbiown nonwoven fabric over the entire surface and thus to increase the KristaNisationsgrad in the meltblown nonwoven fabric over the entire surface.
• inherently rigid, pressure-stable two-dimensional components can be produced.
• the molded meltblown nonwoven fabric can be annealed only part of the surface and so the degree of crystallinity in the meltblown nonwoven fabric are raised only part of the area, so as to increase the rigidity only on component-specific areas or in the continuous grid of the component.
• only the edge regions of the component can be tempered from the meltblown nonwoven fabric so as to make the edge regions of the component more rigid, for example in order to increase the stackability of the component from the meltblown nonwoven fabric.
• a component can be formed by tempering from the meltblown nonwoven fabric and the degree of crystallization can be increased over its entire area in order to produce intrinsically stiff three-dimensional components.
• meltblown nonwoven fabric it is also possible by heat treatment to deform the meltblown nonwoven fabric over part of the area and to raise the degree of crystallization only in this subarea in order to form, for example, one or more spacers or another local functional geometry in the meltblown nonwoven fabric.
• locally compressed or consolidated regions can enhance the functionality, for example for the formation of contact surfaces at attachment points.
• Another object of the present invention is a tempered meltblown nonwoven fabric whose filaments at least in sections and preferably all over a degree of crystallinity of 20 to 80%, preferably from 30 to 75%, more preferably from 40 to 75% and most preferably from 50 to 70%.
• the present invention relates to a meltblown nonwoven fabric with at least in sections and preferably over the entire surface, based on DIN Compressive hardness measured at 60% compression of at least 2 kPa as measured by EN ISO 3386.
• the meltblown VHesstoff invention preferably has a compressive strength at 60% compression of at least 4 kPa, more preferably of at least 6 kPa, more preferably of at least 8 kPa, even more preferably of at least 10 kPa, even more preferably of at least 12 kPa, even more preferably at least 15 kPa, most preferably at least 20 kPa, and most preferably at least 30 kPa.
• a further subject of the present invention is a process for producing a tempered Meitblown nonwoven fabric having a basis weight of 100 to 600 g / m 2 and having a density of 5 to 50 kg / m 3, comprising the following steps:
• a) producing a Meitblown nonwoven fabric preferably by externally supplied with flowing air and stretches by extruding polymer melt through a nozzle before the filaments thereby formed on a support, which is preferably a double suction drum, are deposited and cooled, and
• step b) annealing at least at least a portion of the Meitblown nonwoven fabric prepared in step a) at a temperature between the glass transition temperature and 0, 1 ° C below the melting temperature of the
• meltblown VHesstoff is annealed in step b) for 2 minutes to 2 hours at a temperature which is between 20 ° C below the melting temperature and 1 ° C below the melting temperature of the filaments of Meitblown nonwoven fabric ,
• a temperature which is between 20 ° C below the melting temperature and 1 ° C below the melting temperature of the filaments of Meitblown nonwoven fabric
• FIG. 1 schematically shows a furnace for producing a tempered meltblown nonwoven fabric according to an exemplary embodiment of the present invention.
• FIG. 2 shows schematically a mold for simultaneous molding and annealing a
• Mettblown nonwoven fabric according to another embodiment of the present invention a comparison of the compression hardness of a tempered meltblown nonwoven fabric according to another embodiment of the present invention to the compression hardness of an untempered Meltbtown nonwoven fabric according to the prior art.
• Example 4 shows the results of measuring the sound absorption of the tempered meltblown nonwoven fabric prepared in Example 1 according to the present invention
• Fig. 5 shows the results of the measurement of the absorption coefficient of in the
• Example 1 annealed meltblown nonwoven fabric directly to a
• FIG. 1 shows schematically a belt furnace 10 for producing a tempered meltblown nonwoven fabric according to an embodiment of the present invention.
• the open 10 comprises on wheels 12 guided and driven air-permeable belts 14, 14 ', over which the meltblown nonwoven fabric 15 is guided into and through the oven 10.
• the oven 10 are above and below the two bands 14, 14 ', seen in the conveying direction from right to left in this order, a first blow box 16, a suction box 18 and a second blow box 16' are arranged.
• the meltblown nonwoven fabric 15 is passed through the oven 10 from right to left on the lower belt 14.
• hot air flows into and through the meltblown vitrified material 15 in order to increase the filaments of the meltblown nonwoven fabric 15 to the desired tempering temperature.
• the air flowing through the meltblown nonwoven fabric 15 is sucked off in order to ensure that the meltblown nonwoven fabric 15 is safely flowed through by the hot air and the meltblown nonwoven fabric 15 also does not collapse, but maintains its volume.
• FIG. 2 schematically illustrates a mold 20 for simultaneously molding and annealing a meltblown nonwoven fabric 15 according to another embodiment of the present invention.
• the meltblown nonwoven fabric 15 is held in the desired shape from both sides by appropriately shaped screens 22, 22 ', from which the mold 20 is assembled, and heated to the desired temperature by circulating or flowing hot air for annealing.
• the nonwoven mat produced thereby retains the embossed shape and is dimensionally stable.
• FIG. 3 shows the compression hardness of a tempered meltblown vial at 60% compression with a basis weight of approximately 300 g / m 2 and a density of approximately 15 kg / m 3 according to another exemplary embodiment of the present invention (upper curve). and the compression hardness of an untempered meltblown Nonwoven fabric with the same basis weight and density according to the prior art (lower curve) shown in comparison.
• the compression hardness is shown as compression in% against the compressive stress in kPa. As can be seen from Fig.
• Bet game 1
• meltblown nonwoven fabric having a weight per unit area of 300 g / m 2 and a density of 15 kg / m 3 was prepared by carrying out the meltblown process described in US Pat. No. 4,375,446 has been. Subsequently, this meltblown nonwoven fabric was annealed in a convection oven for 10 minutes at 158 ° C. By inserting the cold nonwoven fabric and opening the oven door, the initial temperature was below the melting point of the filaments of the untempered nonwoven fabric.
• the sound absorption coefficient of the tempered meltblown vial was measured as a function of the thickness-normalized frequency.
• the results are shown in FIG. 4 in curve A as compared with the values obtained with the untempered meltblown nonwoven fabric prepared in the comparative example (curve B).
• the unit of the abscissa is the measurement frequency x absorber thickness / 15 mm.
• the comparison of the results shows that the tempering according to the invention has no negative effects on the sound absorption properties of the nonwoven fabric.
• a tempered meltbottom nonwoven fabric was prepared according to the procedure described in Example 1, except that annealing was performed at 155 ° C for 10 minutes.
• Example 3
• a tempered meltbottom nonwoven fabric was made according to the procedure described in Game 1 except that annealing was performed at 155 ° C for 25 minutes.
• a non-annealed meltbottom nonwoven fabric was made according to the first process step described in Example 1, which was not annealed unlike that described in Example 1.
• Stiffness Hardness Factor ratio of the compressive hardness of the annealed nonwoven fabric of Example divided by the compression hardness of the unannealed nonwoven fabric of Comparative Example

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• 2017
  • 2017-05-22 EP EP17172180.6A patent/EP3406780B1/de active Active
• 2018
  • 2018-05-22 CN CN201880049523.1A patent/CN111226001B/zh active Active
  • 2018-05-22 WO PCT/EP2018/063287 patent/WO2018215402A1/de active Application Filing
  • 2018-05-22 US US16/633,065 patent/US20200165759A1/en not_active Abandoned

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