JPH0376800A - Water-repellant processing of leather and raw hide - Google Patents

Abstract

Use of copolymers obtainable by free-radical copolymerisation of (a) C8-C40-monoolefins with (b) ethylenically unsaturated C4-C8-dicarboxylic anhydrides in the manner of a mass polymerisation at from 80 to 300 DEG C to form copolymers having molecular weights of from 500 to 20,000 g/mol, subsequent solvolysis of the anhydride groups of the copolymers and at least partial neutralisation in an aqueous medium with bases of the carboxyl groups formed in the course of the solvolysis and which are present in the form of aqueous dispersions or solutions, as agents for waterproofing leathers and pelt furs.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a process for water-repelling leather and hides using copolymers based on long-chain olefins and ethylenically unsaturated dicarboxylic anhydrides.

Prior Art West German Patent Application Publication No. 3.730. From the specification of No. H5, it is obtained by polymerizing an olefin having 2 to 40 carbon atoms and maleic anhydride.
It contains a small amount of a copolymer with a molecular weight of 0 g 1 mole, the anhydride groups of which have been completely or partially reacted with an aqueous alkali metal or alkaline earth metal base and the remainder of the carboxyl groups reacted with an alcohol and/or Fuels for gasoline engines are known which have been converted into the corresponding ester groups and/or amide groups and/or ammonium salts by reacting with amines.

From West German Patent No. 2,629,748, CIO-C30 saponified with alkali metal bases or amines
It is known to use copolymers of olefins and maleic anhydride for the densification and fatliquoring of leather and hides. It is also possible to react the hydrolyzed copolymers with alkali metal bisulfites. Since this copolymer is prepared in an organic solvent and this solvent is not removed, the aqueous copolymer dispersions prepared therefrom contain significant amounts of organic solvents such as quidyrol or dodecylpenzole.

Although this dispersion is suitable for fatliquoring leather and raw hides, it cannot be used for water-repellent treatment of leather and raw hides because it contains an organic solvent.

Problems to be Solved by the Invention The object of the present invention is to provide a method for water-repelling leather and raw hides using an improved water-repellent agent.

Means for Solving the Problem According to the present invention, the problem is achieved by: (a) Cm-C4°-monoolefin, (b) ethylenically unsaturated C4-C8-dicarboxylic anhydride, by bulk polymerization at a temperature of 80°C. By radical copolymerization at ~300℃, the molecular weight is 500~20,000g1
0.5 molar, obtained by preparing a copolymer with a subsequent solvolysis of the anhydride groups of the copolymer and at least partially neutralizing the carboxyl groups formed during the solvolysis with a base in an aqueous medium. The solution is to use copolymers present in the form of ~50% by weight aqueous dispersions as water-repellent agents for leather and raw hides.

This copolymer can be used, for example, in West German Patent Application No. 3,
730.885. The copolymer is obtained by copolymerizing monomers of group (a) with monomers of group (b) at a temperature of 80 to 300°C by bulk polymerization. Suitable monoolefins having 8 to 40 carbon atoms are, for example, n-octene-1,2,4,4-trimethylpentene-1,2,4,4-1-limethylpentene-2,
Diisobutene (which exists commercially as an isomeric mixture consisting of about 80% by weight of 2,4.4-)trimethylpentene-1 and about 20% by weight of 2,4.4-trimethylpentene-2), 4. 4-dimethylhexene-1, decene-
1, Dodecene-1, Tetradecene-1, Hexadecene-1
1, octadecene-1, C2o-olefin-1, C2
2-olefin-1, Ca2-ol/74:/1
, Czo ~C24-olefin-1, C24~C2
m-olefin>-1, C,. -Olefin-t, c,,
-olefin-1 and CaO-olefin-1.

These olefins and olefin mixtures are commercially available products. In addition to linear olefins, cyclic olefins such as cyclooctene can also be used. Due to their manufacturing process, these olefins may contain small amounts of inert organic hydrocarbons, eg up to about 5% by weight, and the olefins are normally used in commercially available quality. These do not need to be particularly purified; preferred olefins are CI6-C3
It is a 0-olefin.

Component (b) of the copolymer includes monoethylenically unsaturated C4-C,-dicarboxylic anhydrides, such as maleic anhydride, itaconic anhydride, mesaconic anhydride, citraconic anhydride, methylenemalonic anhydride and mutual mixtures thereof. It will be done. Of the anhydrides mentioned above, preference is given to using maleic anhydride. Copolymer is monoolefin 40~
It contains 60 mol % and 860 to 40 mol % of the abovementioned anhydrous dicarboxes in polymerization and has a molecular weight of 500 to 20,000, preferably 800 to 10,000 g/mol. The copolymer consists of monomers (a) and (b) in a molar ratio of 1.1:1.
Obtained by polymerizing at a ratio of ~1:1. Monomer (0
and (b) in a molar ratio of 1:1, or component (a
) is preferably used in excess of 1% by weight. As is well known, when the monomers of groups (a) and (b) have a high molecular weight, they selectively form a copolymer containing 50 mol% of the monomers (a) and (b), respectively. In the lower case, depending on the type of end group, the molar ratios may deviate from the abovementioned framework, for example if the copolymer distribution begins or ends with monomer (a).

Bulk polymerization at 80-300°C, advantageously 120-200°C
The lowest polymerization temperature that can be selected is advantageously at least about 20° C. above the glass transition temperature of the resulting polymer.The polymerization conditions are selected depending on the molecular weight that the copolymer is to have. . Polymerization at higher temperatures yields copolymers with lower molecular weights; lower polymerization temperatures yield higher molecular weight polymers. The amount of polymerization initiator also influences the molecular weight, generally 0.0% relative to the monomers used during the polymerization. 01-5% by weight of radical-forming polymerization initiator is required. In this case, higher amounts of initiator result in lower molecular weight copolymers. Monomers (a) and (b) can be copolymerized without the presence of a polymerization initiator when the temperature is above 200°C. That is, the use of an initiator is not absolutely necessary.

This is because monomers (a) and (b) undergo radical polymerization even in the absence of an initiator when the temperature exceeds 200°C. Suitable polymerization initiators are, for example, di-t-butyl peroxide, acetylcyclohexane sulfonyl peroxide, diacetyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, 1-butylperneodecanoate, 2.2'-Azobis(4-methoxy-2,4-dimethylvaleronitrile), t-butylperbivalate, t-butylperu-2-ethyl-hexanoate, t-butylvermaleinate, 2,2°-azobis( isobutyronitrile), bis-(t-butylperoxy)cyclohexane, t-butylperoxyisopropyl carbonate, t-butylperacetate, di-
These are t-butyl peroxide, di-t-amyl peroxide, cumene hydroperoxide and t-butyl hydroperoxide. These initiators can be used alone or in admixture with one another. During the bulk polymerization, these are preferably introduced into the polymerization reactor separately or in the form of a solution or dispersion in the monoolefin. In the copolymerization, it is of course also possible to use redox co-initiators such as benzoin, dimethylaniline, ascorbic acid and organic soluble complexes of heavy metals such as copper, cobalt, iron, manganese, nilacea and chromium. By using a redox co-initiator together, the polymerization can be carried out at lower temperatures. The amount normally used of redox co-initiator is about 0.0% based on the amount of monomer used.
1-2000pp, preferably 0.1-1000pp. If the monomer mixture is to be polymerized at the lower end of the temperature range suitable for polymerization and to be completed at a higher temperature, at least two species are used, which decompose at different temperatures and thus have a sufficient concentration of radicals available at each temperature interval. It is advantageous to use an initiator of

To produce low molecular weight polymers, it is often advantageous to carry out the copolymerization in the presence of regulators. For this purpose, customary regulators are used, such as C□-C4-aldehydes, formic acid and compounds containing organic SH groups, such as 2-mercaptoethanol, 2-mercaptopropanol, mercaptoacetic acid, mercaptopropionic acid, t-butylmercaptan,
n-dodecylmercaptan and 7-dodecylmercaptan can be used. Polymerization regulators are generally used in amounts of 0.1 to 10% by weight, based on the monomers.

The copolymerization is carried out in a conventional polymerization apparatus, such as a pressure-resistant polymerization apparatus equipped with a stirrer, a pressure-resistant stirring polymerization kettle, a cassgate, or a tubular reactor. In the case of bulk polymerization, olefin and anhydride are copolymerized in equimolar ratios in the absence of a solvent. The copolymerization can be carried out continuously or discontinuously. For example, the olefin or the mixture of different olefins can be placed in a reactor and heated to the desired polymerization temperature under stirring. As soon as the olefin reaches the polymerization temperature, the ethylenically unsaturated dicarboxylic anhydride is metered in. If an initiator is used, it is preferably metered into the reaction mixture separately or dissolved in the olefin to be subjected to the polymerization.
The polymerization regulators, if used, are added to the mixture to be polymerized, either alone or likewise dissolved in the olefin. The acid anhydride, especially maleic anhydride, is advantageously added to the reaction mixture in the form of a melt. The temperature of the melt is about 70
If the olefin is used in excess, for example a 10% excess, in the copolymerization, at temperatures between Can be removed. The copolymer melt is then advantageously used directly for processing the clothing.

The copolymer thus produced is solvolyzed after cooling to room temperature or preferably in the form of a melt at a temperature of 80 to 180 °C, advantageously 90 to 150 °C, the solvolysis of the anhydride groups of the copolymer being most In simple cases, it consists of hydrolysis followed by neutralization. Particularly advantageous is the treatment in a pressure-resistant apparatus, where the anhydride groups are converted into carboxyl groups by adding water to the copolymer melt obtained in the direct bulk polymerization, and the carboxyl groups of the copolymer are subsequently hydrolyzed by addition of a base. neutralize at least 10% of the

However, hydrolysis and neutralization can actually be carried out simultaneously by adding dilute aqueous base to the copolymer melt. In this case the amounts of water and neutralizing agent are selected in such a way that a dispersion or solution (which is commercially available) containing 10 to 60% by weight, preferably 20 to 55% by weight of solid substance is obtained; Preparation solutions are prepared by dilution to a solids content of 0.5 to 50% by weight.

Copolymers obtained by bulk polymerization can also be solvolyzed by adding primary and/or secondary amines. In this case, solvolysis involves the polymerized monomer (
It is carried out using an amount of amine such that from 10 to 50% of all carboxyl groups resulting from complete hydrolysis from b) are amidated. Neutralization is carried out after the formation of half-amide groups in the copolymer until at least 10% of the carboxyl groups of the copolymer formed during bulk polymerization have been neutralized. Furthermore, it is also possible to carry out the solvolysis using aminocarboxylic acids and their salts, preferably alkali metal salts. Particular preference is given to using alkali metal salts of α-aminocarboxylic acids, in this case the alkali metal salts of sarcosine being particularly preferred.

The solvolysis with salts of aminocarboxylic acids is advantageously carried out in an aqueous medium, in which case the solvolysis is carried out from the polymerized monomer (b) to 100% of all carboxyl groups generated during complete hydrolysis. It is carried out with an amount of aminocarboxylate such that ~50% is amidated. Neutralization takes place after the formation of half-amide groups in the copolymer,
This is carried out until at least 10% of the carboxyl groups of the copolymer formed during bulk polymerization have been neutralized.

Solvolysis can also be carried out by adding alcohol to the copolymer melt obtained during bulk polymerization. In this case, an amount of alcohol is used such that from 10 to 50% of all carboxyl groups originating from the polymerized dicarboxylic acid units are esterified. Neutralization is then carried out, in which case at least 10% of all carboxyl groups originating from the copolymer containing anhydride groups are neutralized.

It is advantageous for 25 to 50% of all carboxyl groups resulting from the polymerized dicarboxylic anhydride to be amidated or esterified in each case. Neutralizing agents include, for example, ammonia, amines, alkali metal and alkaline earth metal bases, such as sodium hydroxide solution, potassium hydroxide solution,
Magnesium hydroxide, calcium hydroxide, barium hydroxide and all amines which are also used for amidating copolymers are suitable. Neutralization is advantageously carried out by adding aqueous sodium hydroxide solution to the copolymer. Neutralization of the copolymer containing anhydride groups is carried out at least to the extent that a water-dispersible copolymer is obtained. This degree of neutralization is at least 10% of all carboxyl groups originating from anhydride groups.

Furthermore, the degree of neutralization is also related to the g-length of the olefin used in each case of component (a). In order to obtain a copolymer that is well dispersible in water or colloidally soluble, the copolymer consisting of a C50-olefin and maleic anhydride is neutralized to at least 75%, but for example consisting of a C20-C24-olefin and maleic anhydride. The copolymer has a degree of neutralization of 50% of the carboxyl groups originating from the copolymer.
%, it can be well dispersed in water.

For copolymers of C1□-olefin and maleic anhydride, a degree of neutralization corresponding to 20% of the carboxyl groups resulting from polymerized maleic anhydride is sufficient to disperse the copolymer in water.

Ammonia and primary and secondary amines can be used to form amides. The amide formation is preferably carried out by reacting the anhydride groups of the copolymer with ammonia or amines in the absence of water, suitable primary and secondary amines containing from 1 to 40 carbon atoms, preferably from 3 to 40 carbon atoms. Suitable amines which may have 30 amines include, for example, methylamine,
Ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, hexylamine, cyclohexylamine, methylcyclohexylamine, 2-ethylhexylamine, n-octylamine, isotridecylamine, tallow amine, stearylamine, oleylamine, Dimethylamine, diethylamine, di-n-propylamine, di-isopropylamine,
Di-n-butylamine, di-isobutylamine, di-tallow amine, di-cyclohexylamine, di-methylcyclohexylamine, di-n-ethylhexylamine, di-n-octylamine, di-isotridecylamine, di-tallow amine , di-stearylamine, di-oleylamine, ethanolamine, di-ethanolamine, n-
Preference is given to using propatoolamine, di-N-propateuramine and morpholine, 0morpholine.

In order to partially esterify the copolymer with anhydride groups obtained during bulk polymerization, the copolymer is reacted with an alcohol. The esterification is also advantageously carried out with exclusion of water. A suitable alcohol has 1 to 40 carbon atoms,
It is also possible to use primary, secondary and tertiary alcohols, which may advantageously contain 3 to 30 alcohols. Saturated aliphatic alcohols as well as unsaturated alcohols such as oleyl alcohol can also be used. monohydric primary or secondary alcohol,
For example, methanol, ethanol, n-propertool, impropertool n-butanol, isobutanol, n-
Pentanol and isomers, n-hexanol and isomers, n-octatool and isomers, such as 2-ethylhexanol, nonanol, decanol, dodecanol, tridecanol, cyclohexanol 1, tallow alcohol, stearyl alcohol and industrially Alcohols or alcohol mixtures having 9 to 19 carbon atoms, easily obtainable by synthesis, such as C4 to C11
-oxoalcohols, C4-C11-oxoalcohols and Ziegler alcohols having from 12 to 24 carbon atoms, known under the names Alfol, are preferably used. Alcohols having 4 to 24 carbon atoms, such as n-butanol, imbutanol, amyl alcohol,
2-Ethylhexanol, tridecanol, tallow alcohol, stearyl alcohol, C1~C1 oxo alcohol, CtS~C1 oxo alcohol, CtZ~
C14-alfol and C4-C1g-alfol are preferably used.

After partial conversion of the anhydride groups into half-amide or half-ester groups, the anhydride groups still present in the copolymer are hydrolyzed. Hydrolysis of the residual hot hydride groups of the copolymer is carried out simultaneously with the still required partial neutralization by adding an aqueous base to the partially amidated or esterified copolymer which still contains anhydride groups. be able to.

The amounts of water and base are selected such that the concentration of the copolymer dispersion or solution is advantageously from 20 to 55% by weight. The pH value of the ready-to-use water repellent is in the range of about 4-10.

The copolymer aqueous dispersion thus obtained is durable and storage stable. This aqueous dispersion is extremely suitable for finishing leather and hides.

This is because this aqueous dispersion has a particularly good water-repellent action and, in addition, also develops a fatliquor and post-tanning action. Leather and raw leather materials treated with this copolymer dispersion exhibit only low water absorption and water permeability.Since the dispersion simultaneously acts as a plasticizer, additives based on natural or synthetic leather oils are often used. No special fatliquoring agents are required, and this dispersion produces high tension, high tensile strength and tear strength in each article. Additional treatment with commercial tanning agents such as vegetable tannins or synthetic organic tannins (Syntan) based on phenolsulfonic acid/phenol/formaldehyde condensation products is therefore often no longer necessary.

Another advantage of the aqueous dispersions that can be used in the present invention is that they do not contain additional emulsifiers. As is well known, leather and hides treated with products containing emulsifiers
After treatment with this agent, expensive measures have to be carried out to inactivate the emulsifier in the leather or raw hide, such as after-treatment with polyvalent metal salts.

The above copolymer dispersions are suitable for all conventional tanned animal hides,
It is particularly suitable for treating tanned hides with mineral tannins such as chromium(I[) salts. Tanned animal hides are usually deacidified before their processing; animal hides can also be colored prior to their processing.

However, the coloring can also be carried out only after the water-repellent treatment according to the invention.

The tanned animal skin is preferably prepared in an aqueous dispersion, preferably in an aqueous bath obtained by diluting the copolymer dispersion with water, at a pH value of 4 to 10, preferably 5 to 8, and a temperature of 20 to 60° C., preferably 30° C. It is advantageous to treat at ~50° C. for 0.1 to 5 hours, especially 0.5 to 2 hours. This treatment is carried out, for example, by walking in a bath; the required amount of copolymer dispersion depends on the amount of leather removed (Falzgewich
t') or 0.001 to 30% by weight, preferably 1 to 20% by weight, based on the wet weight of the raw hide. Fluid volume (FIotLenl
xnge), that is, the percentage weight ratio of processing liquid to product is usually 10 to 1000% based on the amount of leather scraped or the wet amount of raw hide.
, advantageously 30-150%, in the case of raw hides 50-500%
It is.

After treatment with the aqueous liquid, the pH value of the treatment liquid is adjusted by adding an acid, advantageously using an organic acid such as formic acid, to a pH value of 3 to 5, advantageously 3.5 to 4. do.

If customary post-tanning agents are used together with the finishing treatment of leather and raw hides, the treatment with the aqueous dispersions which can be used according to the invention can be carried out before or after the post-tanning step or even in several steps; In this case, the aqueous dispersion is used either before, after or during the post-tanning step. Aqueous dispersions which can be used as water repellents can also be used together with conventional leather and raw leather finishes, such as paraffin-based water repellents and fatliquors. In some cases, this improves the water repellency, fatliquorization and post-tanning action.

1% on each side of the Examples is in % by weight unless otherwise stated. The molecular weight of the copolymer was determined by gel permeation chromatography, in which tetrahydrofuran was used as eluent and subdivided for assay. The polystyrene fraction was used. Tests for water absorption and permeability of treated leathers were carried out using a Burley needle anthropometer according to the International Association of Leather Chemists, International Union of Physical Leather Testing Committees.
r Leder-Che Seal 1ker-VerbInde
, Komission f[Irphysikali
sche Lederpr [Ifung] measurement method IU
P10 (Das Leder J)
, Vol. 12, pp. 36-40 (1961).

Preparation of the aqueous copolymer dispersion Dispersion I A tonic reactor equipped with a stirrer and a metering device prepared for the polymerization was first charged with a C20-C24-olefin-1 mixture [Gulften 20-24, Gulften
f Manufactured by Oil Chemical Company,
Commercial product in USA] 1195 g was placed and heated to 190° C. under a weak nitrogen flow while stirring. 392 g of maleic anhydride heated to 70°C as soon as this temperature is reached
and separately di-t-butyl peroxide 1
Add 6g evenly within 4 hours. The reaction mixture was subsequently stirred at 190° C. for 2 hours and cooled to 90° C. while stirring. 320 g of 50% strength sodium hydroxide solution and 3909 g of water heated to 90° C.
The reaction mixture is stirred at a temperature range of 90-95° C. for 4 hours and then cooled to ambient temperature. A slightly viscous aqueous dispersion with a solids content of 30.2% is thus obtained. The molecular weight of the unhydrolyzed copolymer of olefin and maleic anhydride was 8900 g mol, and 50 mol % of all carboxyl groups formed were neutralized.

Dispersion■ First, octadecene-11 was added to the reactor in which Dispersion I was produced.
19 while stirring in a nitrogen atmosphere.
Heated to 0°C. As soon as this temperature is reached, 588 g of a melt of maleic anhydride and a solution of 27 g of di-tert-butyl peroxide dissolved in 142.8 g of octadecene are added to the reaction mixture separately and within 2 hours each. After the addition of maleic anhydride and peroxide, it is heated for a further 2 hours at 190° C. and then cooled to 110° C. Then, within 1 hour, 522 g of morpholine was metered in.The reaction temperature was kept at 110°C.After the addition of morpholine had ended, the reaction mixture was stirred for a further 2 hours at 110°C, converting the anhydride groups of the copolymer into corresponding half-amide groups. The reaction mixture was then cooled to 90 °C under stirring and cooled separately from each other for 5
480 g of 0% aqueous sodium hydroxide solution and 8680 g of water at a temperature of 90°C were added within 30 minutes, and
Heat at ℃ for 2 hours. A dispersion with a solids content of 25.4% is thus obtained which is viscous at room temperature. The molecular weight of the unsolvolyzed copolymer is 4800 g mol, with 50 mol% of all carboxyl groups originating from anhydride groups.
was present as an amide group, and 50 mol% was neutralized.

Example 1 p) Cutting thickness (Falzs) deoxidized to I value 5.0
1.8 mm of chrome-tanned cowhide was exposed in a tanning tank at 40° C. for 2 hours in a dispersion liquid (1) at a concentration of 15% based on the amount of scraping. The total liquid volume was 150%.

The leather was then colored with 1% by weight of a customary anionic aniline dye. It was then adjusted to a pH value of 3.8 with formic acid, washed, mechanically stretched and dried.

The leather obtained was extremely soft, malleable, well-coated, uniformly colored and had excellent waterproof properties. 15% for testing using Burley needle anthropometer
After 24 hours at a compression degree of 20.9% by weight, water absorption was not observed.

Example 2 Chrome-tanned cowhide with a scraping thickness of 1.8 mm, deacidified to a pH value of 5.0 and colored with 0.7% by weight of a conventional anionic aniline dye, was Dispersion ■
Then, it was sanded and exposed in a tanning tank at 40°C for 1.5 hours.

After this treatment, the leather was brought to a pH of 3.6 with formic acid and finished in the usual manner.

The leather thus obtained was extremely soft and pleasant to the touch, and had excellent waterproof properties. Testing with a Burley needle anthropometer showed a value of 23.7% by weight for water absorption after 24 hours at a degree of compaction of 15%, with no permeation of this amount of water observed.

Claims (1)

[Claims] 1. Radical copolymerization of (a) C_8-C_4_0-monoolefin with (b) ethylenically unsaturated C_4-C_8-dicarboxylic acid anhydride at a temperature of 80 to 300°C by bulk polymerization method. A copolymer with a molecular weight of 500 to 20,000 g/mol is prepared by subsequent solvolysis of the anhydride groups of this copolymer, and the carboxyl groups formed during solvolysis are at least partially neutralized with a base in an aqueous medium. 1. A method for water-repelling leather and raw hides, characterized in that a copolymer present in the form of an aqueous solution or an aqueous dispersion is used.