DE1917457A1 - Process for the production of non-woven synthetic leather with a mixed leather-like texture - Google Patents

Description

uZ: AIOJ 1199 (Pi / J / we)
AKU 1199/10

ALGEKENE KUlISTZIJDE UKIE
Arnhem ₃ Netherlands

¹¹ procedure sas? Hottest, ellub £ -; before?. VlJteolra ^. TXuüvvi ¹ with Bümlschlederarfeigsp '. "^ SehaffsrJi © It"

Priority: April 17, 1968, the Netherlands Ahmelde no .: 68 - 05359

The UoS "A" ~ patent specification 3 067 433- and the corresponding German patent specification 1 146 4-73 describe a process for the production of fleece artificial leather with a velvety texture, according to which a shrinkable fleece containing fibers is subjected to a shrinkage process in V / water and then send impregnated with a solution of a Folymerisata in an organic solvent or with an aqueous polymer dispersion - after which the polymer is coagulated.

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1317457

The polymer used is an elastomer, which is mainly serves as a binding agent for the pasers «One achieves after the aforementioned process products with only limited Säraischlederartiger Nature"

It has been found that polyvinyl alcohol is a hydrophilic synthetic compound because of its properties to water an excellent Ausgang3iaaterial for the production of artificial leather w brass washer, wherein dao behavior de3 polyvinyl alcohols can be gewünsGhtenfalls modified from water with simple means ,,

Polyvinyl alcohol fibers that shrink in an aqueous medium are, are known and can, inter alia, according to U.S. A β patent specification 2,962,762 and the corresponding German U.S. Patent 1,034,477.

The aforementioned fibers are in a known manner in a drying process processed into a fleece or a mat, The thus obtained web consisting of pasers can be made by a needling process be compressed-. If you have one like that, from Pasern existing membrane treated with moderately heated water, the fibers shrink, hardly adhering to one another and not suffering any loss of the j'aeerstructure. Thanks to this Shrinkage process, usually accompanied by some puckering and / or spiraling, becomes an exceptional one dense yet very flexible fleece made of fibers obtained.

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BATH ORIGINAL

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The filler used here for the fleece is also made from polyvinyl alcohol manufactured. To apply it, the fleece is impregnated with an aqueous polyvinyl alcohol solution and then treated with a liquid that prevents coagulation of polyvinyl alcohols is used as a coagulant preferably an aqueous medium such as an aqueous saline solution is used.

The fleece is impregnated with the polyvinyl alcohol solution, e.g. by dipping it or spraying it. Additionally or exclusively, it can be used to achieve a denser filling the surface of the fleece carry out the impregnation process with the help of coating rollers or by padding *

Eb has been found that the shrinkage process of the fleece and can very advantageously carry out the impregnation with the polyvinyl alcohol solution by a one-step process if apply the not yet shrunk, dry fleece directly with it treated with a moderately heated polyvinyl alcohol solution.

Preferably used is a solution having a content of 5 to ■ fO Sew.-5 'polyvinyl alcohol, to a temperature of 30 to 60 ⁰ C heated _ISTC; "

The aim is preferably to have a filler content of about 20 to 20% by weight of polyvinyl alcohol, based on the dry, total volume. For this purpose, the impregnated fleece; with ■. '■ y ^ .v'ii χ * ".. · ; eß' / uXsöii:".: -: = 3as coagulation bath introduced _r di < ^j

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BATH ORIGINAL

on the concentration of polyvinyl alcohol used by dtr **

for
g bBw.Aen required degree of filling required Bruok

be asked.

In order to provide the nonwoven filled in the aforementioned way its suitability for use as wash-leather, to the polyvinyl alcohol, more precisely, are insolubilized in hot water of for example at least 8000, the polyvinyl alcohol-filler · ψ to diesem.Zweck treated nan the nonwoven rushes an aoetalizing agent, some of the hydroxyl groups of the polyvinyl alcohols being converted. The acetalizing agent can be, for example, a monoaldehyde or a dialdehyde, with which the filled fleece is treated in an acidic, aqueous medium at an elevated temperature.

Finally, the non-woven fabric treated in the aforementioned manner is thoroughly washed, with the last step if necessary Washing stage a neutralizing agent and / or one

Softener used, and finally dried *

An artificial wash leather produced by the aforementioned method is of the same quality as natural wash leather in many respects equivalent or even superior. Various material tests have shown, however, that the artificial wasole leather not yet completely satisfied, especially with regard to properties that are important in practice, such as the squeeze and surface grip.

909846/1189 8At) original

The object of the invention is "a process for the production of non-woven synthetic leather with properties" in particular a chamois leather-like one Texture to make available, which require an excellent usability of the product as wash leather.

The invention thus relates to a method for producing non-woven synthetic leather with a chamois-like texture, in which a shrinkable fleece containing a shrinking process is subjected in an aqueous medium and provided with a polymer filler, which is characterized by that he

(a) a material consisting essentially of trunkable polyvinyl alcohol fibers existing fleece is subjected to a shrinkage process and successively or simultaneously with a water-soluble synthetic resin and with an aqueous polyvinyl alcohol solution treated,

(B) the fleece is then treated with a liquid that causes the coagulation of the polyvinyl alcohols and in the the synthetic resin is practically insoluble,

(c) the filled fleece then a treatment with a Subjects to acetalizing agents, in which the polyvinyl alcohol is made insoluble in hot water and d · » Synthetic resin is at least partially removed from the fleece,

and iT; * ~ ■ ■. "-" ■ - ■

(d * the fleece treated on the aforementioned fleece washes and dried, "

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Surprisingly, according to the invention , it has been found that the aforementioned deficiencies can be eliminated if the fleece is treated with a water-soluble synthetic resin before the coagulation of the polyvinyl alcohol filler.

Synthetic resins suitable for the aforementioned purpose must be immersed in water or soluble in a polyvinyl alcohol solution, but in the Liquid used to coagulate polyvinyl alcohols may be insoluble and when treated with an aoetalizing agent effective agents are at least partially extracted from the fleece "

Preferably one uses eir. 'Resin based of melanin and formaldehyde from proportions of units derived from formaldehyde or from melamine such that the resin is water soluble. Such synthetic resins are commercially available » common.

The resin material can be applied to the fleece in a separate process step or together with the polyvinyl alcohol "In the latter case, the best results are obtained if the fleece is subjected to a shrinking process in a hot aqueous medium and then in an aqueous solution of polyvinyl alcohol and synthetic resin ··>

nearly
zes of / room temperature.

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"ORIGINAL '-

warmed polyvinyl alcohol solution. Aqueous salt solutions, in where the synthetic resin is practically insoluble, such as an approximately 25 # sodium sulfate solution, can generally serve as a coagulant for the polyvinyl alcohol. The resin solution will usually used in a concentration or amount such that the batt at this stage of treatment is about 10 to 20 Oew.-jf. Contains synthetic resin, based on the dry, unfilled Fleece",

During the subsequent treatment with the aoetallic agent, a large part of the synthetic resin deposited on the fleece is extracted from it. Ale general rule "that the non-woven material thus obtained contains more than 50 i> of the originally deposited amount of resin. An acidified formalin solution with a temperature of at least 40 ° 0 is preferably used as an aoetalating agent.

The product obtained is then processed to the end in the usual way. In the production of the artificial wash leather of the invention, when a synthetic resin is used, in particular a melanin resin containing methylol groups, a considerable improvement in the suede-like material is achieved Condition, in particular with regard to the crushing »resp. Surface grip. Though nan knows with no certainty the factors to which this beneficial influence is attributed v / eMer. nut, one assumes that this is based on an interaction - "is based on facts. The influence can be based on

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^ß ADORIGINAL

because the methylal groups of the synthetic resin become effective),

that a precipitate of urine forms, which is possibly chemically bound, the fibers probably being loosely connected to one another locally, or that the synthetic resin has a pore-forming effect during the treatment of the filled fleece with the acetalizing agent.

It should be mentioned that the aforementioned polyvinyl alcohol fibers can also be endless polyvinyl alcohol threads. In addition, the fleece used as the starting material can contain a small amount of other natural and / or synthetic fibers. Nevertheless , the rule is that the other fibers should not exceed a proportion of 5% by weight with regard to the special properties of the polyvinyl alcohols, which are decisive for the successful implementation of the process of the invention and for the quality of the wash leather obtained .

The examples illustrate the invention.
Example 1

: Needled 5in consisting of polyvinyl alcohol fibers fabric having a weight of about 120 g / m '"v / ill be and then immersed in V'asser of 4-5 ⁰ G The surface shrinkage of the fleece to a Paktor of 1.4. .

The shrunken fabric is squeezed off, dried at 5O ⁰ C and at room temperature in a solution on * 1 wt. -Part of a handele'-

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■ ßAD ORIGINAL

usual melaiain-formaldehyde resin immersed in 2 parts by weight of water. The nonwoven fabric is squeezed to a liquid content of about $ 200, and dried at 50 ⁰ C. The dried fleece contains about 15 ^c ß> of the melamine-formaldehyde resin, based on the fleece used as the starting material.

Subsequently, the nonwoven fabric in an aqueous, 6.5 $ strength PoIyvinylalkohollösung of 2O ⁰ C is immersed, to a Plüssigkeitsgehalt of 650 ^c ß> squeezed off and then immersed in a 20-ji strength sodium sulphate solution of 25 ⁰ C. After an immersion time of 10 minutes, the filled fleece is slightly dried and then immersed for 7 minutes at 50 ° C. in an acetalizing bath consisting of a formalin solution acidified with sulfuric acid and containing sodium sulfate. After this treatment, the product is thoroughly washed and dried. The fleece obtained still has a content of 2 to 2.5% by weight of the Mölamin porraaldehyde resin, based on the total product.

The above procedure is for comparison purposes without the Treatment with the commercially available. Melamine resin repeated

J) he two products thus obtained show a good effect in Yorwendung as -Waschleders terms of squeezing or ^"Oberr.? .Äch 'nt> riffs is the invention nit the commercial llelaminharz behan.leite Waschleder untreated interpreting-.1J oh überlfigeno; luß ~ mlu; n the first.e product needs a kö r -; - .;} .... - '; i.}.!. tTj ρ-mna '-ur-' ^ r ο ο km ?, ng _β

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SAD ORIGINAL

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Expressed in relative good ratings, it has that which has been treated according to the invention with a commercially available melamine resin Wash leather has a surface grip, i.e. a frictional resistance on glass under standard conditions of 28 or one through a hand test determined the squeeze grip of 6j the untreated Wash leather has corresponding values of 20 and 4.5.

Example 2

The needled non-woven starting material of Example 1 is immersed in the solution of commercial melamine resin of Example 1 at room temperature, squeezed to a liquid content of 200 $> and dried at 5O ⁰ C.

The fleece is then shrinked into a 6.5 # Polyvinyl alcohol! *) Solution of 27 ° C and it will continue Proceed according to example 1.

By treatment with the commercially available Kelaminharz the shrinkage behavior of the polyvinyl alcohol is -Pasern 3tark so influenced such that even at 27 ⁰ C a surface Schrurapffaktor is obtained from 1.4 *

In order to produce an untreated, according to this example. To achieve the same shrinkage factor for wash leather, a polyvinyl alcohol ^{solution of 45 0} C must be used.

Surface or de.t squeeze handle of the nib dem commercially available

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Wash leather treated with high thermal resin is 26 and 6 respectively, the corresponding properties of the untreated wash leather 17 and 4.5.

Example 3

The needled, the shrinkage process subjected and dried, consisting of polyvinyl alcohol fibers from Example 1 is ^{immersed in a 6.5 #, aqueous polyvinyl alcohol solution of 20 0} O, which additionally contains 10 parts by weight of a commercially available melamine resin. The immersed fleece is then squeezed off and the procedure according to Example 1 is continued.

In comparison to the untreated washed leather from Example 1 the surface or Quetsoh handle of the wash leather thus obtained is 25 and 6, respectively.

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Claims (3)

Patent to g ρ r Ü ο h e Process for the production of fleece artificial leather with a sole-type texture by treating a fleece containing sohrumpable fibers as an aqueous medium causing the shrinkage and by incorporating a polymer isat-PUll et of fs in the fleece, characterized in that. man \ (a) a fleece consisting essentially of shrinkable polyvinyl alcohol fibers is subjected to a shrinking process and treated successively or simultaneously with a water-soluble synthetic resin and with an aqueous polyvinyl alcohol solution, (b) the fleece is then treated with a liquid, which causes the coagulation of the polyvinyl alcohol and in which the synthetic resin is practically insoluble, (c) the filled fleece then undergoes a treatment with one acetalizing agent, subject, in which the polyvinyl alcohol is insoluble in hot water and the synthetic resin is at least partially removed from the fleece, and (d) washes and dries the nonwoven fabric treated in the aforementioned manner. 2. The method according to claim 1, characterized in that one a water-soluble helamin formaldehyde resin is used as the synthetic resin. 909846/1189 COPY ν. 3. The method according to Anspruoh 1 or 2, characterized in that in treatment step (a), the fleece is first treated with an aqueous solution of the synthetic resin at room temperature, dries and then impregnated with the polyvinyl alcohol solution. · · 4 «Method according to claims 1 to 3, characterized in that the coagulation in treatment stage (b) takes place by means of an aqueous salt solution. 5ο Method according to claim 1 to 4, characterized in that. the treatment with the acetalizing agents in the (c) Stage / by means of an acidified formalin solution at a temperature of at least 40 ⁰ G is carried out. COPY 9098 4 6/1189