DE1419399A1 - Process and dispersion for binding random fiber nonwovens - Google Patents

Description

Chicopee Manufacturing Corp,

CHICOPEE MANUFACTURING CORPORATION, 501 George Street, New Brunswick, New Jersey, V.St.A.

Process and dispersion for binding random fiber nonwovens.

With this registration the priority will be from May 13th, 1960 U.S. Patent Application Serial No. 28 867 claimed.

Random fiber fleeces are generally made with the help of adhesive Binders bound to the non-woven fabric structure to be connected to a coherent, self-supporting fleece »The binding agents used for this purpose are primarily cellulose derivatives, such as hydroxyethyl cellulose, carboxymethyl cellulose and regenerated cellulose or viscose are used. These binders are particularly suitable for joining cellulose fibers, because in this case there is a chemical affinity between the binder and the fibers »

However, the cellulose derivatives have the disadvantage as binders that they harden into horn-like masses during the binding process.

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and that, therefore, since the binder is responsible for the physical strength of the final product, the bonded Random fiber fleece loses the more softness, the larger it is physical strength it possesses.

So far, efforts have been in vain to improve the softness, flexibility, drapability and foldability of the cellulose derivatives to improve bound tangled nonwovens, reduce their stiffness jsυ, improve their elongation at break and their Reduce shrinkage during processing »

It has now been found that the softness, flexibility, drapability and foldability of bound with cellulose derivatives Random fiber fleeces increased, their stiffness decreased, their elongation at break increased and their shrinkage during processing can be reduced if one of the solution of the cellulose derivative prior to coagulation and regeneration, a microdispersion of colloidal polyolefin particles with certain Particle sizes and added in certain proportions.

The inventive method for binding tangled fiber webs by impregnation with aqueous alkali solutions of alkali-soluble cellulose derivatives, which can be converted into cellulose or water-insoluble cellulose derivatives, and subsequent Conversion through coagulation and regeneration exists in that solutions of the cellulose derivatives mentioned are used, which are a water-insoluble polyolefin with average Particle sizes less than 100 microns contained in dispersion, and in which the weight ratio of the cellulose derivative to the polyolefin in the range of about 5 s 95 to 95: was

Solutions are preferably used in which the particle size of the dispersed polyolefin is between about 0.05 and 1 micron.

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ORIGINAL INSPECTED

Suitable cellulose derivatives are those that are in the form of aqueous Alkali solutions are available or can be converted into such and are derived from these solutions in "form of cellulose or of Allow insoluble cellulose derivatives to separate out, e.g. by heating or by chemical action, such as by adding Alkali or acid. Particular cellulose derivatives of this type are sodium hydroxyethyl cellulose, sodium carboxymethyl cellulose and Sodium cellulosic anthogenate.

It is already known to impregnate or coat paper or fabric with solutions or dispersions of polyethylene (British Ρε / tentsehrift 491 804). That about this Polyethylene used for purposes does not need to have a prescribed particle size, and that used for impregnation Solutions do not contain cellulose derivatives "

It is also known to use aqueous polyethylene dispersions, which can also have any particle size, for Sizing of woven or knitted fabrics · to be used. These dispersions can be water-soluble as fillers Cellulose derivatives contain (British Patent 518 917) <.

It is also known to use porous, highly absorbent sheet-like structures by impregnating fiber fleeces with rubber dispersions with the addition of a water-soluble cellulose derivative to produce as a pore former by the structures after impregnation of a coagulating and optionally vulcanizing Treatment are subjected, whereupon the cellulose derivative is removed by washing with water and that now porous structure is dried (German patent 930 119)

Polyethylene dispersions have also been used for sizing paper, the dispersions being the pulp in the Hollander added and later coagulated (British patent specification 726 364).

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Finally, it is known to combine fibers consisting of tetrafluoroethylene polymers with non-fibrous tetrafluoroethylene polymers to impregnate (U.S. Patent 2,764,506).

The polyolefin to be used according to the invention to increase the softness, flexibility, drapability, durability and elongation at break and to reduce the stiffness and shrinkage when processing in the form of a colloidal dispersion in the cellulose derivative solution can be selected from a large group of polyolefins., Examples for such polyolefins are inter alia. Polyethylene, usually represented by the chemical formula -CHpCHp- _χ , polypropylene _{, usually represented by the chemical formula -CH 9} OH (OH.,) -, poly-1-butene, usually represented by the chemical formula -CHpOH (C ₅ H ₁ -) - represented, poly-2-butene, usually represented by the chemical formula -CH (OH,) OH (OH,) - _χ , and polyisobutylene, usually represented by the chemical formula -GH ₉ G (GH,) ₉ -represented . It should be noted that the polyolefin materials which can be used according to the invention are saturated chemical compounds and do not contain any carbon-carbon double bonds, even if they are produced by polymerizing monomers such as ethylene (high and low density), propylene, 1-butene, 2-butene and Isobutylene, which in turn is unsaturated and contains carbon-carbon double bonds. Because the polyolefin materials are saturated and have no carbon-carbon double bonds, they are of excellent stability and chemical inertness and free from the main causes of discoloration and gumming in aging. It is not necessary to stabilize these polyolefins against oxidation, as is the case with rubber, which requires a vulcanization treatment, whereby the occurrence of unpleasant odors is avoided. In addition, the polyolefins are non-toxic and harmless. So makes the use of polyolefins in accordance with

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of the invention the finished products for surgical, medical and sanitary purposes particularly suitable.

The polyolefins are commercially available as aqueous emulsions and can be used as such. If you are initially available as a finely divided powder, they can be mixed with traces of an IT wetting agent in aqueous media Disperse the formation of stable emulsions with the desired pesticide content »

The mean particle size colloidal dear polyolefin particles must be within a predetermined particle size range provided that the objectives of the invention are achieved to Λ. It has been found that particles having an average diameter of less than about 100 microns are suitable. Even more finely divided micro-dispersions having an average particle diameter on the order of less than about 1 micron have been found to be particularly useful when this finer particle size is more suitable for the particular fabric being treated ”. The lower limit of the particle size of the polyolefin particles depends on the intended purpose. For the usual purposes of the invention, an average particle size as low as about 0.1 micron has been found to be satisfactory. A special, commercially available colloidal polyisobutylene dispersion with a mean particle size of about 0.5 micron ™ and a mean size distribution in the range of about 0.05 to about 1 micron is very suitable Palis desirable or necessary, even finer particle size ranges can be used, depending on the coming each into consideration circumstances.

The polyolefin colloidal dispersion can be any desired Way can be introduced into the solution of the cellulose derivatives, for example by simple addition with stirring. One virtually all proportions of the two ingredients have been found and there are indications of complete compatibility

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no polyolefin coagulation could be seen. The polyolefin particles are in the dispersed phase, whereas the cellulose derivative is dissolved in the continuous phase is.

The colloidal polyolefin-cellulose derivative solution can be fully impregnated on the paser structure, e.g. by dipping, Spray or inlay process or by intermittent binder pressure or other working methods for the predetermined or random binder deposition can be applied to the fiber. If the solution is limited by printing processes in the form Binder surfaces are applied, such surfaces can the shape of continuous or discontinuous, straight or wavy lines, circles, rings, rectangles, squares, Diamonds, triangles, ellipses, ovals or similar straight or curved figures or other regular or show irregular figures »

After this solution has been applied to the nonwoven fabric, the dissolved cellulose derivative is made insoluble or coagulated and converted back into the water-insoluble form of the cellulose derivative preferred as a binder.

The amount of binder (solids-dry basis) to be applied to the fiber fleece or the fiber layer serving as the starting material can be as small as about 1 wt. , preferably about 10 to 25 wt . In the case of impregnation in a discontinuous pattern, the portion of the surface covered by the binder makes up between about 7 and 35% of the total surface of the fleece. In general, however, it is preferred that the binder-containing areas comprise at least about 12 and no more than about 30 percent of the total surface area of the web.

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The weight ratios (dry basis) of the cellulose binder and colloidal polyolefin in the nonwoven film can vary within wide limits. About 5 to 95 parts by weight of the cellulosic binder can be used with about 95 to 5 parts by weight of the polyolefin. For the usual purposes of the invention, it is preferred to use about 25 to 75 parts by weight of the cellulosic binder and about 75 to 25 parts by weight of polyolefin. It should be noted that these proportions are those present in the dry nonwoven webs and that when initially blending or combining the oil solution and the colloidal polyolefin solution, account must be taken of the g

Solutions have a strongly fluctuating solids content. For example, contains a Viscoselösung usually lies between 6 and 7 wt .- $ cellulose, a Eikrodispersion normally whereas ύοϊι polyisobutylene up to 55 parts by weight fo weight or more solids.

The layer of overlapping and intersecting fibers which is processed to form the nonwoven webs of the invention can be obtained by any of the numerous conventional techniques of arranging or rearranging fibers into a nonwoven. These operations include carding, spinning loosening - and yarn waste (garnetting), air-laying, papermaking methods % and the like. Individual fleeces or thin layers obtained by one or more of these working methods can be placed on top of one another so that a thicker layer is available for the transfer into a fleece. Usually the individual fibers extend in several different directions in general alignment with the main plane of the web, overlapping, intersecting and supporting one another to form an open, porous fiber structure. The degree of fiber orientation in a certain direction depends mainly on the principles established for the nonwoven manufacturing process from _o formed by air-laying process nonwovens usually have a very low

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ring orientation in a certain direction and are basically isotropic, made by carding and with Garnett openers Fleeces, on the other hand, are mainly oriented in the longitudinal direction of the fleece. Each type of fleece has its own special features Properties and is useful for certain purposes «In this context, reference is made to the USA patents 2,862,251, 2,705,687, 2,705,688 and 2,676,363 in which typical methods and devices for the production of such fiber webs are described o

The fiber fleece can be natural or synthetic, vegetable, animal or mineral fibers, such as cotton, silk, wool, vicuna, mohair, alpaca, flax, Eamie, jute, synthetic or artificially produced fibers, such as cellulose fibers, in particular cuprammonium, viscose or regenerated fibers Cellulose fibers, crosslinked cellulose fibers such as "Gorval ¹ * and" Topel ", cellulose ester fibers such as cellulose acetate (" Celanese ") and cellulose triacetate (" Arnel "), the saponified cellulose ester fibers such as" Fortisan "and" Fortisan-36 ", the polyamide fibers, such as nylon 420, nylon 6 (polycaprolactam), nylon 66 (hexamethylenediamine adipic acid), nylon 610 (hexamethylenediamine sebaic acid), nylon 11 (11-aminoundecanoic acid "Rilsan"), protein fibers such as "Vicara", halogenated hydrocarbon fibers such as "Teflon "(Polytetrafluoroethylene), hydrocarbon polyolefin fibers such as polyethylene and polypropylene, polyester fibers such as" Kodel "and" Dacron ", vinyl fibers such as" Vinyon "and ^M Saran ⁿ , acrylic fibers such as "Orion", "Acrilan", "Creslan", modacrylic fibers such as "Dynel" and "Verel", and mineral fibers such as glass and metal.

The length of the fibers in the parent web can be between about 9.52 or 12.7 mm (3/8 or 1/2 inch) and about 63.5 mm (2 1/2 inch) or more, depending on the particular characteristics, which are required or desired in the finished web vary. If desired, the fiber layer can, if desired in a subsequent processing stage, with about 1 or 2 wt .- # up to about 100 wt .- # other fibers than

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ORIGINAL

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those of spinning length are offset »In special cases all fibers of spinning length can be replaced by fibers of other lengths «. These other fibers can be a papermaker's length ranging from about 9 »53 mm (3/8 inch) to extends down to about 1.58 mm (l / l6 inch) or less, with the shorter lasing in the conventional procedures are usually not used in the manufacture of nonwovens

Examples of these short fibers for papermaking are the natural cellulose fibers, such as wood pulp and wood fibers, BaumwoHinters, cotton hull fiber, mineral lasers, such as asbestos, glass, rock wool, or any of the above-mentioned natural or synthetic lasers with lengths from less than about 9 »53 mm (3/8 inch) down to about 1.58 mm (1/16 inch) or less.

The yarn count or denier of each synthetic laser mentioned above is preferably in the approximate range Thickness of the mentioned natural lasers, so deniers in the range of about 1 to 5 are preferred «If any If greater opacity or coverage is desired, special fiber deniers can be down to about 3/4 or even about 1/2 can be used if desired Use deniers up to about 8, 10, 15 or above. The lower and upper limit values of the denier are of course based on the needs and requirements for the production of a certain laser fleece according to the machines and processes for the production of the same and the like.

The weight of the starting fiber fleece can be relatively within further limits fluctuate above a predetermined minimum value and depends on the requirements for the intermediate product or the finished product. A single thin fiber fleece, for example that produced by a card, can have a weight of about 2.72 to 19.4 g / m (35 to

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250 grains per square yard) or more be used for the purposes of the invention, Im Bahmen however, it is general practice of the invention to use nonwoven laser weights from about 7 to 62.6 g / m (90 to 800 grains per square yard) to be used, if larger web weights are desired are, for example up to about 155 g / m (2000 grains), then several of the individual nonwovens can be combined to form a layer structure combined with the desired weight. The product of a card can be folded and doubled and tripled with itself be used to achieve the heavier weight, or several cards and the individual products can be used placed or layered on top of each other to achieve the same purpose.

The following examples illustrate the invention without restricting it.

example 1

A carded fleece with a weight of about 31 »1 g / m (400 grains per square yard) is used as the starting fiber material. the Yiscose rayon (regenerated cellulose) fibers of 1 1/2 denier and a staple length of about 39.7 mm (1 9 / I6 inch) contains »The improvement in softness, Flexibility and jamming resistance become as follows determined: Samples of the card web with the dimensions 45.72 × 20.32 cm become weak with polyvinyl alcohol binding agent pre-tied -,

The viscose (sodium cellulose xanthate) used to treat the card web samples is a Starida solution with 7 ° alkali and 7 ° cellulose. The polyolefin added to the viscose is polyisobutylene, which is used as an elastomer emulsion having a solids content of $ 55, an average particle size of about 0.5 microns, and a particle size distribution of about 0.05 micron diameter (minimum) to about 1 micron diameter (maximum) . The elastomer emulsion has a density of about 0.96, a liter weight of about 0.97 kg

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CS ,! pounds per gallon) and a pH value of 5 to 6 "

Eight different binder preparations with different proportions of viscose and polyisobutylene are made as follows:

sample
No. Viscose polyisobutylene polyisobutylene
(g) (g) (# solids) 0 0 whole
binder
(^ Solids) 1 200 25th 42 7.0 2 175 50 64 10.7 3 150 75 76 14.4 4th 125 100 84 18.1 5 100 125 90 21.8 6th 75 150 94 25.4 7th 50 175 97 29.0 8th 25th 32.9

These binder preparations containing viscose and polybutylene mix well and are smooth and creamy. They are practically evenly applied by hand ironing techniques oriented card web samples up to a wet pick-up of about 300 wt .-? S applied. For coagulation and regeneration the usual acid coagulation and regeneration procedures are used for viscose, which are followed by longer washing in water and connect air drying. The processing takes place with the card web samples in a relatively relaxed state. The physical ratings of the products formed are given below:

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sample Final dry weight 2 (980) G-urley Final width Tear resistance No. g / m 4 grains / yard ^) (840) Stiff (along) 76.1 (750) Ness 1 65.3 (790) 370 13-1 / 2 84 2 58.3 (830) 215 15-1 / 2 74 3 61.4 (830) - 17-1 / 2 - 4th 64.5 (810) 102 18-1 / 2 80 5 64.5 (790) 56 19th 84 6th 62.9 34 19-1 / 4 92 7th 61.4 27 19-3 / 4 108 8th 21 19-1 / 2

The Gurley stiffness tester is described in The Paper Trade Journal of December 20, 1934 on page 43. The readings thereon and the rub resistance readings are relative and indicate variations or improvements over the polyisobutylene-free control (No. ₀ 1). The improvement in softness and flexibility results from the steady decrease in the Gurley stiffness values with an increasing percentage of polyisobutylene in the binder preparation. The increase in dimensional accuracy results from the decrease in the shrinkage in width of the samples with an increasing percentage of polyisobutylene in the binder preparation. The increase in the dry tensile strength must also be taken into account. The reduced stiffness, the increased softness and flexibility and the reduced shrinkage without any obvious loss of wet strength, dry strength or color fastness make the nonwoven films suitable as wipes.

Example 2

The starting material is a card web with a weight of 46.6 g / m (600 grain per square yard) made of 100 <f ° light viscose rayon fibers (regenerated cellulose) with a denier of 1 1/2 and a pile length of about 39, 7 mm (1 9/16 inch). 4 different binding agents are used to bind the card web

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systems used: I ₀ 100 $> usual viscose solution, containing 7 $> alkali, 7 $ cellulose and diluted with one part 6 ^ -iger alkali solution per 3 parts of viscose solution, 2. a Yiseose-polyisobutylene emulsion, where the polyisobutylene to the viscose is added in an amount such that it 40 percent by weight of the total solid in the finished preparation accounted 3 · the same emulsion as in (2) except that the polyisobutylene 60 wt _o - represents $ of the total solids, and 4 ". the same emulsion as with the exception that the polyisobutylene 90 wt _o in (2) - represents $ of the total solids "corresponds The polyisobutylene used about the" used in Example 1

The applied binder pattern is a discontinued "Iceland binding" -Druckmuster, as indicated in Figure 1 of US Patent 2,705,687 _o The printing process was not difficult and could regarding the material carryover and low Naßwanderung be considered excellent "The information About the nature of the yiies and the ratings are listed below:

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Sample binder fleece final dry ₂ G urley # elongation no. Weight g / m ₂ stiff lengthwise across

(Grains / Yard) is called

1 (D K 49.7 (640) 22nd 7th 28 2 (2) K 51.5 (664) 18th 9 49 3 (3) K 54.1 (696) 6th 10 59 4th (4) K 55.3 (712) - 12th 88 IA (D M. 54.1 (696) 18th 9 25th 2A (2) M. 55 (708) 11 9 28 3A (3) M. 56.2 (723) 5 12th 25th 4A (4) M. 52.2 (672) - 11 70 IB (D K 55.3 (712) 9 10 47 2 B (2) K 53.5 (688) 8th 11 53 3B (3) K 47.3 (608) 6th 12th 59 4B (4) K 54.1 (696) 6th 14th 91 IC (D M. 49.7 (640) 5 9 36 2 G (2) M. 54.1 (696) 5 11 37 3G (3) M. 45.2 (582) 4th 12th 38 40 (4) M. 44.8 (576) 4th 12th 44

The improvement in softness and flexibility results from the relatively constant decrease in gurley stiffness readings with increasing percentage of polyisobutylene in the binder composition. The Gurley Stiffness Readings are not completely reliable or reproducible at low values and are therefore in the list above been omitted. The increase in the percentage elongation at break in the longitudinal and transverse directions must also be taken into account. The reduced stiffness, increased softness and flexibility and the increased elongation at break without any noticeable loss Wet strength, dry strength or color stability make the fiber fleece films for use as washcloths for hospitals suitable.

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As used herein, the term "Masslinn" includes nonwoven fabric (Sometimes labeled with the letter M) Nonwoven sheets such as those described in U.S. Patents 2,705,686 to 2,705,688 are describedc The term ^ Keybak "bundled Fabric (sometimes referred to by the letter K) is intended to include the nonwovens described in the United States patent 2 862 251 are given »

Example 3

The fiber starting material is a "Keybak" bundled material with a weight of 46.6 g / m (600 grains per square yard) made of 100 io viscose rayon fibers (regenerated cellulose) with a denier of 1 1/2 and a pile length of about 39 > 7 mm (l 9/16 inch). 3 different binder systems are used to join the carded nonwovens: l _o ) 3 parts standard viscose solution with a content of 7 $ alkali and 7 7% cellulose, diluted with one part water, but without the addition of polyolefin, 2.) 3 parts standard viscose solution and 1 part an aqueous polyethylene dispersion with a solids content of 40 Grew * - $ and 3 ») 2 1/4 parts of standard visose solution and 1 3/4 parts of an aqueous polyethylene diapersion with 40 Gewo-9? Solids * The polyethylene has a high molecular weight and is a very finely divided, dispersible powder with a particle size of 90 microns (diameter) or less «

The binders are applied to carded nonwovens in an interrupted print pattern that extends c [.uer over the width of the Card web extending wavy lines, namely 4 wavy lines each 25.4 mm, measured in the longitudinal direction. Common methods of coagulation and regeneration are used. The physical ratings of the received Products are as follows:

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Sample Cellu- Poly- Endtrooken-τρ Transverse strain G-urley-No. loose ethylene weight g / m _? traoken wet stiffness solids solids (Grains / Yard)

1 5-1 / 4 0 48.9 (630) 11 38 18

2 5-1 / 4 10 49.2 (633) 25 66 16

3 3 14 49.1 (632) 26 69 10

The reduced stiffness, the increased softness and drapability and makes the increased transverse elongation without any appreciable loss of wet strength, dry strength or dye stability the nonwoven film is suitable as a single use washcloth.

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Claims (1)

Patent attorney. 2OOO Hamburg 5O A * T Qrosse Bergstrasse, 223 Telephone 3S β2 95 Teleoramm address: Doellner patent Chicopee Manufacturing Corp., New patent claims Claims Process for binding random fiber nonwovens by impregnation with aqueous alkali solutions of alkali-soluble cellulose derivatives, which are converted into cellulose or water-insoluble cellulose derivatives let transfer, and subsequent conversion by coagulation and regeneration, characterized in that that solutions of the cellulose derivatives mentioned are used, which are a water-insoluble polyolefin with average particle sizes of less than 100 microns contained in dispersion and in which the weight ratio of the cellulose derivative to the polyolefin is in the range of about 5: 95 to 95 ί 5 " 2, the method according to claim 1, characterized in that a Solution is used in which the particle size of the dispersed polyolefin is between about 0.05 and 1 micron » The method according to claim 1 or 2, characterized in that a solution is used which is polyethylene as the polyolefin contains. 909815/0927 4 »Method according to claim Io or 2, characterized in that that a solution is used which contains polypropylene as a polyolefin » 5. The method according to claim 1 or 2, characterized in that a solution is used which, as the polyolefin, is polybutene (1) contains. 6 *. Process according to Claim 1 or 2, characterized in that a solution is used which contains polyisobutylene as the polyolefin 7β method according to claim 1 to 6, characterized in that k that a solution is used which contains sodium hydroxyethy cellulose as the cellulose derivative. 8. The method according to claim 1 to 6, characterized in that a solution is used which is used as a cellulose derivative Contains sodium arboxymethyl cellulose 9ο method according to claim 1 to 6, characterized in that that a solution is used which contains sodium cellulose xanthogenate as the cellulose derivative. ΙΟ »Colloidal dispersion for carrying out the procedure according to claims 1. to 9. » characterized in that it consists of an alkaline aqueous solution of an alkaline solution P ~ chen cellulose derivative, which is a water-insoluble Polyolefin with mean particle sizes less than 100 microns in a weight ratio of cellulose derivative to polyolefin in the range from 5 ί 95 to 95 s 5 contained in dispersion ORIGINAL 909815/0927