CS213168B1 - Highly effective stabbed textile for filtration of liquids - Google Patents

Abstract

The invention falls within the production of textile of the industry, while in its own way into the chemical industry. High-performance needled fabric for filtration liquids, particularly liquid suspensions such as pigment pigments, with the ability to capture fine particles o a size of 0.5 to 5 µm consists of synthetic fibrous web, in particular polypropylene, which is thermally cut and on one surface is polypropylene or other synthetic fibers melted and converted in a smooth amorphous synthetic layer material at the injection site felting needles irregular tears allowing the flow of filtered liquid to layer of nonwoven web layer.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-performance needled fabric for filtering liquids, in particular liquid suspensions such as pigment dyes, having the capability of trapping fine particles of 0.5-5 µm, comprising at least one sheet. On the side of the fabric, the surface of the cloth material is transformed into an amorphous surface layer, while inside the fabric thickness, the bundled fibers formed by the needling are deformed, broken, broken or distorted under the amorphous surface layer. Various woven and nonwoven filter fabrics are used to capture valuable products, such as pigment inks, on frame filter presses. Commonly used dense cotton fabric captures particles below 5 Λ “» when laid in two layers. A major disadvantage is its short life in an aggressive, particularly acidic environment, which is predominantly found in the manufacture of pigment pigments.

Of the nonwoven fabrics, for example, a needled fabric consisting of a carrier synthetic fabric provided with a synthetic fiber web on both sides is currently used. Both the fabric and the web are of non-shrinkable fibers and are stitched together. Both surfaces of the fabric are fused. This fabric, known from MS. according to AO no. 171 779, has proven to be very effective in industrial air filtration, but it is not sufficient to capture particles of size 5 jun, because of its low density for this purpose.

For the same reason, non-woven fabrics protected by Czechoslovakia are not suitable for filtration of liquid suspensions. AO no. 198 852. This fabric is formed from needlepunched fiber synthetic web. One side is melt and smooth, so that it resembles paper rather than fabric, while the other side has the nature of a soft fabric with a randomly arranged but predominantly lying pile formed from individual fiber webs. The porosity of the fused side is between 75 and 9%, while the other side has a porosity of 90 to 99%. The needle-punched nonwoven is not compacted by punching prior to melting, so that it is not sufficiently dense and therefore suitable for the sophisticated filtration of pigment inks.

Finally from MS. according to AO no. No. 193,320 is a known needled fabric consisting of a synthetic backing fabric and a synthetic fiber web. At least one side of the fabric is fused. Prior to melting, the fabric is thickened by punching, which both reduces its area by 3 to 45% and deforms the bundles of binder fibers formed in the thickness of the fabric when needled by felt needles from some of the fleece fibers. The degree of concentration is relatively small because the carrier fabric prevents the precipitation. Although this fabric is highly efficient in air filtration, it cannot be used to filter liquid suspensions where particles below 5 µm must be collected because its density is not sufficient for such filtration.

These disadvantages are overcome by a high-performance needled fabric for filtering liquids, in particular liquid suspensions such as pigment dyes, with the ability to trap fine particles of 0.5 to 5 jun, consisting of at least one fibrous material reinforced by the injection molding and fibrous material converted into an amorphous surface layer, while inside, in the thickness of the fabric are

213 Ιββ underneath the amorphous coating layer deformed, ie, bent, interrupted or erased bundles of binder fibers formed during the filling process, are characterized in that they consist only in the whole thickness of a synthetic fiber web, in particular polypropylene, which is at least monolayer and formed from at least one fineness at least a portion, for example 50 to 100 wt. % are erect or unfixed fibers and the other fibers are fixed.

One embodiment of the fabric comprises a synthetic fiber web consisting of two equal portions of needlepunched nonwoven webs made of polypropylene fibers of at least two kinds of fineness, for example four finenesses ranging from 1.5 to 2.8 dtex. Another possible embodiment of the high performance stitch fabric according to the invention comprises a single layer saturated fiber web consisting of polypropylene fibers of one fineness, for example

1,3 dtex. However, fibers other than propylene, such as polyester, polyamide or mixtures thereof, may also be used. The type of fibers used depends on the nature of the liquid to be filtered. In all embodiments of the fabric of the invention, the nonwoven synthetic fiber web exhibits a weight of 600 to 800 g / m, a porosity of 60 to 75% and a flow rate of 1 to 10 liters / cm / hr.

Unrefined fibers are understood in the description and the subject matter of the invention to be synthetic shrinkable fibers which are thermally precipitated prior to the textile treatment so that they have a higher residual shrinkage than the fixed fibers. For example, propylene fibers which are very suitable for the fabrics of the present invention exhibit shrinkage of at least 15 to 40% for shrinkage fibers, up to 1% for fixed fibers and 1 to 15% for unmixed fibers at a temperature of 130 ° C for 10 minutes. The degree of shrinkage of the non-fixed fibers is between the average degree of residual shrinkage of the fixed fibers and the average degree of shrinkage of the shrinkable fibers.

The high-performance needling fabric for the filtration of liquids according to the invention is based on a detailed analysis of the knowledge gained from the use of the aforementioned fabrics known in the art. of the inventions of AO no. 171,779, 198,852 and 193,320, from which they assume their advantages, which it improves to form a high-performance filter fabric meeting the demanding requirements for filtering liquid suspensions. The first, just known fabric, adopts a non-molten surface, which improves in that the surface layer of molten surface fibers is 0.1 to 0.3mm thick, which is an average of 10% of the fabric thickness, and remains there at the felting points needles, cracks of 0.01 to 0.3mm for the passage of liquid into the thickness of the needled fleece. In the second known fabric mentioned above, the use of only a synthetic fiber web without a carrier fabric is used for the production of the fabric, but it improves its filtering effect by reducing porosity to 60-75%. Of the third known fabric, it assumes the deformation of the binder bundles by precipitation of the fabric, which however increases significantly by up to 70%, thereby increasing the weight of the fabric to 600 to 800 g / m. By combining and improving the above advantages, a surprisingly excellent filtering effect has been achieved by the spoo fabric which readily captures fine particles of 0.5 to 5.0 m at a flow rate of 1 to 10 liters / cm per hour, using relatively inexpensive domestic material, in particular polypropylene fibers that resist both acidic and alkaline liquids, so that the life of the filter fabric is also extended.

The advantages of the invention stand out better from the description of the examples of manufacture of the proposed fabric.

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Example 1

Of a fiber blend consisting of 75% by weight of unfixed and shrinkable polypropylene staple fibers of 1.5 dtex and 25% by weight. % of the fixed polypropylene staple fibers of fineness 1.2 to 1.7 dtex, two identical webs of 240 g / m 2 are produced, which are then pre-consolidated by needling.

The two pre-reinforced webs are laid on top of each other and joined and reinforced by stitching on both sides with a total number of 5 - 0 stitches / cm.

The 500 g / a needlepunch thus obtained is thermally precipitated at a temperature of 156 to 161 ° C until an average precipitation of about 60% in the blank area and a weight of about 670 g / m 2 is achieved.

Finally, an amorphous surface layer of molten surface fibers is formed on one side of the precipitated infused preform on a known radiant heat melting device and cooled press rolls, which, after being pressed between the cooled rolls, is 15 mm in diameter, smooth on the surface. irregular cracks at the felting needles, with cracks in the range of 0.01 to 0.5 mm. The fabric has an average porosity of 65% and a flow rate of 5 l / cm / hr.

It is also possible to use fibers other than polypropylene, such as polyester, polyamide or mixtures thereof. The type of fibers used depends on the nature of the liquid to be filtered.

Example 2

From a coarse polypropylene staple fiber with a fineness of 1.5 dtex, a fiber web of 520 g / m 2 is produced, which is pre-consolidated by needling.

Then, the pre-consolidated web is stitched with a total specific number of 560 stitches / cm. This needlepunch of 240 g / m ² is thermally precipitated at a temperature of 156 to 161 ° C until an average precipitation of about 70% is achieved in the blank area and a weight of about 800 g / m 2 * dd and finally on a known infrared emitter. cooled press rolls, on one side of the precipitated needlepunch formed an amorphous surface layer of molten surface fibers, which after pressing between cooled rolls on the surface is smoothed and adjusted to an average thickness of 0.10 mm, leaving irregular cracks at the injection sites felting needles. The fabric has an average porosity of 60% and a flow rate of 1 liter / cm / hr.

Example 5

Of a fiber blend consisting of 50% unfixed polypropylene staple fibers of 1.5 dtex, 50 wt. % of the fixed polypropylene staple fibers of 2.8 dtex, two equal webs of 200 g / m 2 are produced.

The two webs are laid on top of each other and joined and solidified with a single-sided needling of 160 stitches / cm.

The 550 g / m needle punch produced in this way is thinly precipitated at a temperature of 159 to 164 ° C until an average precipitation of about 46% is achieved in the blank area and a weight of about 600 g / m ·

Finally, on a known melting apparatus, an amorphous 0.5 mm thick surface layer of molten surface fibers, which is 0.5 mm in diameter thick, forms radiant heat and pressed between the cooled rollers on the hair side of the precutting needled blank on the surface of the flame with irregular cracks at the felt needles. The fabric exhibits an average porosity of 75% and a flow rate of 10 liters / cm / hr.

Claims (3)

A visco-active needling fabric for filtering liquids, in particular liquid suspensions such as pigment dyes, having the capability of trapping fine particles of 0.5 to 5 µm in size, comprising at least one sheet of stiffened synthetic fiber material and one textile stand the surface of the fibrous material is transformed into an amorphous surface layer, while inside, at the fabric thickness, the underside of the amorphous surface layer is deformed, i.e., bent, interrupted or disrupted by the binding fibers formed by needling, characterized by a damping that a synthetic fiber web, in particular a polypropylene web, which is at least monolayer and formed from at least one fiber fineness, at least a portion of which, for example, 50 to 100 wt. % fibers are coagulated and / or unfixed and the other fibers are fixed. 2. High performance needled fabric according to claim 1, characterized in that the synthetic fiber web consists of two identical needlepunched nonwoven webs made of polypropylene fibers of at least two types of fineness, e.g. four finenesses ranging from 1.3 to 2.8 dtex. . 3. High-performance needled fabric according to claim 1, characterized in that the fibrous web is converted on one surface into an amorphous surface layer of a selected thickness, p e.g. 0.1 to 0.3 mm, has a weight of 600 to 800 g / m 2, a porosity of 60 to 75% and a flow rate of 1 to 10 liters / cm / hour, being made of synthetic fiber material, polypropylene, polyester, polyamide or mixtures thereof.