DE2036879B2 - Mixed fiber fleeces, in particular for diaper covers and other hygienic purposes - Google Patents

Description

The invention relates to mixed fiber nonwovens produced by the wet route and staple fibers as well as a binding agent that binds the fibers together to form a coherent mass.

Mixed fiber fleeces are referred to below as Probably single nonwovens of any size as well as continuous nonwovens of constant width, which can be wound on spools, understood.

It has long been known for the production of nonwovens different fiber materials, for example Cellulose fibers, synthetic fibers and / or synthetic fibers individually or in combination with one another and to connect them with each other with the help of various methods. Usually the nonwovens are either dry on textile machines using aerodynamic methods or made by carding or on paper machines by slurring the fibers in water and applying the slurry to the fourdrinier wire of the paper machine. Regardless of the In the respective manufacturing process, the fibers must be connected to each other and to one another to ensure the necessary cohesion and the fleece for the intended use to give the necessary mechanical properties. So the dry process was very detailed described needling, a mechanical process in which the fibers are perpendicular to the Web direction are felted, as well as connecting the fibers by impregnating with a corresponding chosen resin. In the case of the wet process, it has already been recommended to use the aqueous fiber dispersion Binding agent, for example a latex, to be added or the dehydrated and dried fleece mass to be added impregnate. Papers with improved wet strength, for example, by adding about 20% Obtained polyacrylonitrile fine fibers. With other binding processes, low-melting points are used in the fleece mass thermoplastic fibrils or fibers introduced, which with appropriate heat treatment melt and weld the fibers together; their share is at least 5%. All of these binding methods but lead to nonwovens whose properties do not always meet the intended uses are fully adapted, especially when high mechanical strength in dry or humid environment, better tensile strength, better burst strength, greater softness or flexibility, etc. are desired.

It has now been shown that mixed fiber nonwovens that contain a certain careful combination of synthetic fibers, natural fibers and synthetic fibers and in which the fibers are bound with polyacrylic fibrils, are characterized by high wet and dry strength, improved tensile strength as well as flexibility, soft grip and large eyesight distinguish and therefore especially * diaper covers and other hygienic and medical Purposes are suitable.

The mixed fiber nonwovens according to the invention for diaper covers and sanitary napkin covers and similar hygienic articles contain at least 45 parts by weight, preferably 50 to 55 parts by weight viscose rayon; 15th up to 20 parts by weight of bleached unground softwood pulp; 1 to 10 parts by weight ground polynosic fibers; 5 to 15 parts by weight of polyamide fibers and 15 to 25 parts by weight of polyacrylonitrile fibers.

The binder fibrils are made by precipitating a polyacrylic latex in a coagulating liquid in a manner known per se, for example as described in French patent specification 1516178, obtain. The latex can be a latex made from homopolymers of acrylic acid, acrylic acid esters such as methyl acrylate, Ethyl acrylate, butyl acrylate or copolymers of the various acrylic compounds with one another and optionally with other ethylenic monomers such as vinyl acetate, butyl maleate etc. be. Mixtures of these polymers and / or copolymers are advantageously used.

The use of fibrils made from an acrylic polymer as a binder in the manufacture of Nonwovens on the wet route offer special advantages: The added polyacrylic fibrils encase the nonwoven fibers not, as is the case with impregnation with a liquid binder, but they set preferably at the points of intersection of the fibers and stick them only here at one subsequent heat treatment. The fibrils do not disappear or run, but rather remain their structure of small particles. The disadvantages of the impregnation process, with the fibers completely Glue together and the gaps are blocked, so that the fleeces become rough feel, are not flexible enough and therefore often require mechanical post-treatment such as Creping must be subjected, sometimes reducing the mechanical properties of the Nonwovens are severely impaired, do not occur.

The mixed fiber webs according to the invention have the textile properties of the fibers themselves, from which they are composed, d. H. So feel, appearance, flexibility or softness, high absorption capacity for liquids, all of the essential properties that are aimed for in nonwovens. About that In addition, the mechanical properties are noticeably improved, especially when the nonwovens are in used in a damp environment. Finally, the fleeces are characterized by great flexibility and a good view based on the homogeneous distribution of the fibers is made possible by the fact that they can be printed in whole or in part with colored motifs, which makes it pleasing Appearance and also the mechanical properties are improved.

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An advantageous use has been found on the weight control

Area of the wayfinding article, for example as v «, t ™,« -vm * ~ ii "ι <* i" _n / in _mm ? S

Covers for wüideln or sanitary napkins and similar SSST ^ äÄ VdfnÄ) mT ? 5

ARTICLE THE NEW NÄSÜS? 7Ϊ «η / 32 ^ To

Mis ^ r ^ correspond ^ naUenWrungen s SS? S '^ enSen.Nadelhö ^

of such products: they feel soft, they are pulp 15

pleasant to look at, ventilated improved mecha- Polynosische'viskoselzeÜwoile TYPE BX

™ Ψί ¹ ^ l T * Naßfestigjceit, tensile strength grinding degree 83 ° Schopper 5

and burst strength, and are also inexpensive. Polyacrfl fibrils (binder) 20

The production of the new mixed fiber cover takes place io ^{JJ v}

according to the general procedure used in papermaking

nen way of working. The French patent specification 1516178 on the Lengsieb is made from a latex

a paper machine accumulated pulp has been obtained dewatered, which is obtained from a mixture of methyl

sert, dried at temperatures of about 130 ° C acrylate, ethyl acrylate and acrylic acid homopoly-

and optionally a further heat treatment 15 mers and a terpolymer made of butyl maleate,

subjected at 130 to 180 ° C, which consisted, for example, of vinyl acetate and butyl acrylate,

a hot air oven, on a new one accordingly to the The fiber dispersion was additionally with 0.6%

heated drums or between calender rolls in front of an aqueous solution of a cationic polyamide

is taken. The nonwovens can be added according to the usual epichlorohydrin resin, based on the

Process in various ways with heat at ao Fasennasse.

for example, shrunk and / or mechanically treated. The fiber suspension was then left on the long delt will. It has been shown that when you run into the sieve of a paper machine; the pulp usually used for impregnating fleece was dewatered, dried at about 130 ° C and The latex binder is replaced by polyacrylic fibrils undergoing a further heat treatment at 150 ° C and throw synthetic fibers into the masses of fibers with as.

high shrinkability such as polyamide fibers. The obtained mixed fiber nonwoven fabric had the following

Polyacrylic fibers, the usual operations properties:

of impregnation and subsequent drying, weight per unit area 20 g / m ²

skipped and, if necessary, directly through the tear length, dry ...... 1800 m

a heat treatment with steam the textile intrinsic 30 tearing length] wet .......... 700 m

Shafts of the mixed fiber nonwovens are formed Tear number, D / G ........ 10

can, being very pliable and soft crepe Products that do not look rough- The values given are mean values that are in feel. Running direction and in the transverse direction of the sheet

The following example is intended to elucidate the invention in more detail.

purify. The following were determined and measured: For comparison, a mixed fiber fleece was the same

length dry and wet according to the French norm of weight per unit area (20 g / m ² ) from the same fiber suspension

AFNOR NF Q 03 004 and the tensile strength according to sion but without the addition of polyacrylic fibrils and

ASTM D 2 261-64 T. cationic polyamide-epichlorohydrin resin

40 places. Those determined under the same conditions

Example properties of this fleece were as follows:

It was a mixed fiber fleece for bandages or

Diaper covers manufactured; the material barrel of a Pa tear length, dry 800 to 1000 mm

The piercing machine contained a dispersion with 10 g / l of the breaking length, not measurable when wet

following mixture: * 5 Tensile strength not measurable

Claims (1)

Claim: Mixed fiber nonwovens, especially for diaper covers and other hygienic purposes, with high dry and wet strength and improved tensile strength, containing 15 to 25% thermoplastic binder fibers, characterized in that they a) at least 45% viscose rayon, 15 to 20% bleached unground softwood pulp, 1 to 10% ground polynosic fibers and 5 to 15 ⁰ Zo polyamide fibers and b) contain the binder in the form of fibrils made from an acrylic polymer. 15th