AT520236B1 - Continuous fiber non-woven sheet - Google Patents

Abstract

The invention relates to a method for producing a continuous fiber nonwoven sheet (2), wherein an endless fiber fleece (1), in particular synthetic fibers, formed by punctiform joining of the fibers (3) at connection points (4) comprising polypropylene fibers or polyethylene terephthalate fibers, is guided and compacted by a calender with smooth rolls such that the fibers (3) of the continuous fiber web (1) are at least partially fused to form a film (5) and an endless fiber web produced by this process Film (2).

Description

description

ENDLESS FIBER FLEECE FILM

The invention relates to a process for producing a continuous fiber nonwoven film. Furthermore, the invention relates to a continuous fiber nonwoven film produced by the process according to the invention.

In particular, for the production of sausage casings, other food packaging or the like, it is essential that on the one hand a corresponding vapor permeability and on the other hand, a corresponding oxygen permeability and smoke permeability is possible. This requirement also applies to the wrapping or covering of other food products such as meat, cheese, chocolate and the like.

So far, sausages are either filled into natural casings, or art casings from collagen and optionally cellulose fibers are used. With regard to the use of natural casings, it should be noted that these are only available in certain quantities and quantities. The art casings of collagen and optionally cellulose fibers, however, require additional special treatment, on the one hand especially in the production of artificial casings and on the other hand in their preservation and storage of the same.

As an alternative, nonwoven products, in particular continuous fiber nonwoven products, can be used for wrapping the foodstuffs. However, this has the disadvantage that fleece has no optimal tear behavior and tends to fraze when tearing the sausage casing. In addition, oxygen permeability is too high for most food products.

The object of the invention is to overcome the disadvantages of the prior art and to provide a method for the production of a nonwoven material, which reduces fraying of the sausage casing when tearing. Furthermore, the oxygen and water vapor permeability of the material produced should be in an acceptable range for sausage production.

These and other objects of the invention are achieved in that a made of uniform fibers, in particular synthetic fibers, produced by selective connection of the fibers at connection points, continuous fiber fleece is passed through a calender with smooth rolls and compacted, so that the fibers of the continuous fiber fleece at least partially fused to a film.

In the method according to the invention, the raised webs are melted at the edge of the connection points, pressed wide and partially ther-mobbed in the surface like a film.

In particular, the continuous fiber web used as the starting material may comprise polypropylene fibers or polyethylene terephthalate fibers. The starting material may in particular comprise pure PP / PE as well as PP / PE bicyclo fleece as well as polyester nonwoven webs.

By a partial fusion of the fibers, the properties of a film are mixed with those of a nonwoven and it is produced a hybrid material. Due to the interruption of the continuous fiber structure by partially formed film areas, a nearly paper-like tear behavior is produced. There is no fraying and the tear direction is essentially isotropic.

The strength is increased by up to 20% and the elongation is reduced to 35% compared to the original values.

In addition, the oxygen and water vapor permeability is reduced compared to a pure continuous fiber fleece. However, since individual unmelted fiber-containing areas again have a very high oxygen and water vapor permeability, the average permeability is still higher than that of a pure Folienma material.

According to the invention, the oxygen and water vapor permeability can be changed by different degrees of fusion.

The formation of a film structure and the adhesion of the continuous fiber nonwoven film according to the invention is reduced to the food product, which allows, for example, easier peeling of the sausage.

According to a further inventive feature can be provided that the rollers are maintained at a substantially constant temperature. As a result, a substantially constant degree of fusion of the fibers is achieved.

According to another feature of the invention can be provided that the surface temperature of the rollers for the processing of continuous fiber web between 100 ° C and 250 ° C, in the processing of polypropylene nonwoven between 145 ° C and 170 ° C, at PE between 100 ° C and 125 ° C, and in the processing of polyethylene terephthalate nonwoven between 200 ° C and 240 ° C.

As a result, an adjustment of the roller temperature is reached at the softening temperatures of the fibers to be processed. By varying the temperature, a variation of the degree of fusion can be achieved, whereby properties such as tear resistance, oxygen and water vapor permeability can be controlled.

According to a further feature of the invention can be provided that the thickness of the continuous fiber fleece during calendering by 10% to 40%, preferably by 14% to 21%, is reduced.

In addition to the partial formation of a film and a reduction in thickness compared to the continuous fiber fleece is achieved. Nevertheless, the nub structure formed by the connection points is maintained, whereby, for example, spices adhere well to the continuous fiber nonwoven sheet.

According to another feature of the invention can be provided that the distance between the rollers is between 0.1 mm and 0.2 mm. The thickness of the continuous fiber nonwoven fabric used as starting material can be about 1.5 mm.

According to another feature of the invention can be provided that the acting on the introduced into the calender endless fiber web pressure between 5 bar and 30 bar.

According to a further feature of the invention can be provided that the rotational speed of the calender rolls is between 5 m / min and 25 m / min.

The variation of the process conditions, such as the distance of the rollers, the contact pressure or the rotational speed of the rollers during calendering determines the properties of the produced endless fiber fleece film. This provides optimal control over the parameters of the final product.

According to another feature of the invention can be provided that the roller combination in the form of steel / steel or steel / plastic, in particular rubber, is executed. Other materials may also be provided for the rollers. Among other things, the material of the roller determines the pressure conditions acting on the continuous fiber fleece. By varying the material of the rollers, for example, a different expression of the nub structure defined by the connection points can be achieved. Furthermore, it is possible to smooth the surface of the endless fiber fleece film with steel rollers, for example. A further object of the invention is to provide a material that can replace known packaging materials of food products and does not have the disadvantageous properties of, for example, nonwoven products used in the prior art.

These and other objects of the invention are achieved by a continuous fiber nonwoven film, which is produced by the process according to the invention.

According to a further feature of the invention can be provided that the continuous fiber nonwoven film has a water vapor permeability of 1 to 200 g / m2 per day.

By the water vapor permeability, for example, the drying rate of a packaged sausage is determined. The combination of foil and continuous fiber fleece leads to optimal properties for the food industry. Furthermore, the water vapor permeability also determines the diffusion rate of, for example, flavorings, such as essential oils of spices or smoke flavor.

According to the invention it is provided that after calendering about 90% of the total area of the continuous fiber nonwoven sheet consists of the film formed by fused fibers. This film has definable oxygen permeability to optimize the drying process of the packaged product.

Further features of the invention will become apparent from the claims, the embodiments and the figures.

In the following the invention will be explained in more detail with reference to an embodiment. 1 shows a schematic side view of an endless fiber fleece; FIG. 2: shows a schematic side view of an embodiment of an endless fiber fleece film according to the invention; FIG. 3a shows a schematic plan view of a continuous fiber fleece; Fig. 3b: A schematic plan view of an endless fiber nonwoven sheet according to the invention.

Fig. 1 shows an endless fiber web 4, which is used as starting material for the inventive method. The lateral view shows a schematic fiber 2 or more superimposed fibers 2. The fibers 2 are compressed in the manufacturing process of the continuous fiber fleece 4 punctually at connection points 3. As a result, a holding together of the fibers is achieved. This results in a funnel-shaped depression with a flank. 6

Typically, the fibers are plastic such as polyethylene, polypropylene or polyethylene terephthalate. Such a continuous fiber fleece 4 has a high permeability to water vapor and gases. Further, when cracked, it shows anisotropic properties because it preferentially cracks along the fiber direction.

Both aspects are disadvantageous if, for example, sausage products are to be packed in fleece: The sausage dries quickly and when tearing fringes the fleece.

Fig. 2 shows a side view of an endless fiber fabric sheet 1 produced by the process according to the invention by calendering the continuous fiber fleece 4 shown in Fig. 1. The schematic view also shows a fiber 2 or more superimposed fibers 2. Furthermore, areas are too see, in the calendering a film 5 was formed. During calendering, the nubs formed by the connection points 3 are pressed together in the continuous fiber fleece 4, and the fibers 2 are melted together to form a foil 5 due to the preferably elevated temperature of the rollers of the calender. In addition, as can be seen from a comparison of FIGS. 1 and 2, the height of the nubs formed by the connection points 3 is reduced, which also leads to a reduction in the overall height of the continuous fiber nonwoven sheet 1 compared to the continuous fiber nonwoven 4.

In this embodiment, smooth rolls of steel were used for the production of the continuous fiber nonwoven sheet 1 according to the inventive method. These were kept at a constant temperature of about 150 ° C. The starting material used was an endless fiber fleece 4 with polypropylene fibers.

In addition to the paper-like isotropic tear properties of the continuous fiber nonwoven sheet 1, the water vapor permeability of the continuous fiber nonwoven sheet 1 at 30 g / m 2 and day is also in an optimum range for sausages. When using other continuous fiber webs 4 as starting material and other calendering conditions, continuous fiber nonwoven films with different properties can be produced.

3a shows a schematic plan view of a continuous fiber fleece 4 as it is used for the production of a continuous fiber nonwoven sheet 1. The fibers 2 comprise polypropylene and are held together at connection points 3. The connection points have a similar shape as shown in FIG. 1, ie they are essentially funnel-shaped with flanks 6.

In this schematic representation, the deepest regions of the connection points 3 are illustrated by a dashed line. The flanks 6 of the connection points 3 extend analogously to the lateral view in FIG. 1 around these deepest regions.

3b shows a schematic plan view of an endless fiber web 1 according to the invention after the calendering of the continuous fiber fleece 4 shown in FIG. 3a. The fibers 2 are fused together to form a film 5. In particular, in the region of the flanks 6 of the connection points 3 has formed a film. As a result, the same advantageous properties are achieved, as already described in the embodiment of FIG.

REFERENCE LIST 1 continuous fiber fleece film 2 fiber 3 connection point 4 continuous fiber fleece 5 foil 6 flank

Claims (10)

claims 1. A process for producing a continuous fiber nonwoven sheet (1), wherein a made of uniform fibers (2), in particular synthetic fibers, by punctiform joining of the fibers (2) at connection points (3) produced, continuous fiber fleece (4), in particular comprising polypropylene Fibers or polyethylene terephthalate fibers, is guided and compacted by a calender with smooth rolls such that the fibers (2) of the continuous fiber fleece (4) are at least partially fused into a film (5), characterized in that after calendering about 90 % of the total area of the continuous fiber nonwoven sheet (1) consists of the film (5) formed by fused fibers (2). 2. The method according to claim 1, characterized in that the rollers are maintained at a substantially constant temperature. 3. The method according to claim 1 or 2, characterized in that the surface temperature of the rollers for the processing of the continuous fiber fleece (4) between 100 ° C and 250 ° C, in particular in the processing of polypropylene nonwoven fabric between 145 ° C and 170 ° C, in PE between 100 ° C and 125 ° C and in the processing of polyethylene terephthalate nonwoven between 200 ° C and 240 ° C. 4. The method according to any one of claims 1 to 3, characterized in that the thickness of the continuous fiber fleece (4) during calendering by 10% to 40%, preferably by 14% to 21%, is reduced. 5. The method according to any one of claims 1 to 4, characterized in that the distance between the rollers is between 0.1 mm and 0.2 mm. 6. The method according to any one of claims 1 to 5, characterized in that on the introduced into the calender endless fiber web (4) acting pressure between 5 bar and 30 bar. 7. The method according to any one of claims 1 to 6, characterized in that the rotational speed of the calender rolls is between 5 m / min and 25 m / min. 8. The method according to any one of claims 1 to 7, characterized in that the roller combinations include steel / steel or steel / plastic, in particular rubber. 9. Endlosfaservlies film (1), prepared by a process according to any one of claims 1 to 8. 10. Endlosfaservlies film (1) according to claim 9, characterized in that it has a water vapor permeability of 1 to 200 g / m2 per day.