Title of Invention

"PROCESS FOR PRODUCING A LEATHER DRESSING AGENT"

Abstract A process for producing a leather dressing agent obtained by A) polymerization of al) 70-100 wt. % of at least one of(meth)acrylic acid, acid chlorides thereof, and anhydrides thereof with a2) 0-30 wt. % of other water-soluble monomers copolymerizable with al), and a3) 0-20 wt. % of water-insoluble monomers copolymerizable with al) and a2), to form a polymer, B) reaction of the polymer from A) with amines of formula R1--NH--R2 wherein Ri represents a C12-C30 alkyl or alkenyl residue, and R2 represents H, a C1-C4 alkyl or C1-C2 hydroxyalkyl residue, optionally C) reaction of the amines not bound to the polymer from A) with (meth)acrylic acid to give N-substituted P-aminopropionic acids and optionally, acylation of the amines not bound to the polymer from A), or the N-substituted p-aminopropionic acids formed, D) neutralization and dispersion, of, the product obtained from B) and if C) is carried out, of the product obtained from C), wherein the monomers al), a2) and a3) are subjected to free-radical polymerization, the polymer obtained is then reacted either immediately or subsequent to solvent removal with the amines of formula Ri—NH--R2, wherein Ri and R2 have the above meanings, at least part of acid groups present in the polymer being converted to amide groups, followed by partial or complete neutralization of remaining carboxyl groups using dilute base, optionally with addition of water.
Full Text The present invention relates to a process for producing a leather dressing agent.
The invention relates to new leather dressing agents for the manufacture of leathers having low contents of voia-tiles, particularly for car upholstery high-quality leatners, a process for producing said agents, and their use in manu facturing low-fogging leathers. Car upholstery leathers muse meet specific criteria. On the one hand, softness is essen tial, as is light-fastness and resistance to heat influence on the other hand, and finally, the so-called fogging behav¬ior. In DIN 75201, fogging is defined as condensation of volatiles evaporated from the vehicle interior equipment on the glass panes, particularly the windshield. That same stan¬dard also describes a gravimetric and a retlectometric proce¬dure for characterizing the fogging "behavior of leather.
2? 498,634 A2 recommends specific polymers for the manufacture of low-fogging leather, where the dispersions are substantia iy free of organic solvents and contain an amphi-philic copolymer consisting of a predominant part of at least one hydrophobic monomer and a minor part of at least one hydrophilic monomer, in a gravimetric test according to DIN 75201, the treatment of leather using these dispersions pro¬vides qood results. There is no disclosure of reflectometric examination;;.
The amphiphilic copolymers are preferably produced in an aqueous emuision polymerization. However, due to the dif ferent hydrophilicity of the copolymers employed, this inher ently gives rise to problems with the copolymerization behav ior which, in the extreme case, may result in the situation that each of the monomers undesirably forms separate homo polymerates. Another consequence of the per se. unfavorable solution conditions is an expensive subsequent processing in order to destroy residual monomers. To achieve good emulsion
stability, it. is also necessary to add a sufficient amount of an emuisifier (lauryl sulfate was used in the examples men tioned), which may give rise to waste water problems m leather processing.
Furthermore, it is well-known to produce fat chemicd raw materials by polymer-analogous reaction with fatty alco hols. Fundamental principles are described in Fat sci. Technol. 92, No. 10, pp. 397-400. Even though possible fields of use have been discussed, applications inthe manufacture of leather have not been described.
DE A2 05 839 Al describes the reaction of poiymer-izates of a) 30-100 itvole-% of unsaturated dicarboxylic anhy¬drides, b) from 0 to 70 mole-% of one or more vinyiaromatics, c) 0-7 0 mole-% of vinyl esters of 0-C1-C8 carboxylic acids, d) 0-50 mole-% of C2-C6 olefins, e) 0-30 mole-% of unsaturated C3-C5 carboxylic acids, and up to 10% of other copolymeriza-ble monomers;, with hydrophobic amines or alcohols. The re¬sulting products impart particular softness to leathers treated therewith.
One drawback of this procedure is the high amount of poorly polymeriaable dicarboxylic anhydrides, which is why severe conditions of polymerization must be chosen to obtain a low ratio of low molecular weight substances in the final product, which is required for good fogging behavior. This fact is confirmed by the data in the examples: polymerization temperature at the boiling point of the xylene solvent, about 136-140'C, .at least 3 hours.
EP 166,392 BE describes a process for the production of polymers which contain both lateral hydrophobic groups and lateral aikoxylated groups and are obtained according to common methods by a derivatization of polymers subsequent to the actual polymerization process. Thus, it is preferred to produce polymers from sijnple monomers such as acrylamide

and/or acrylic acid using conventional polymerization, fol¬lowed by der:.vatization using a mixture of primary or second¬ary hydrophobic amines and primary or secondary aiicoxyiated amines. Such polymer derivatives are used as -chickening agents and dirt-solvi.ng agents.
It was therefore the object of the invention to pro¬vide new leather dressing agents which are easy to produce, substantially auto-emulsifying and low in residual monomers, a process for their production, and a process for manufactur¬ing leather using said agents, wherein leathers are obtained which have exceedingly low contents of evaporating voiatiles (low-fogging leather), as determined according to both gravi¬metric and reflectometric measuring procedures, the other important properties of leather, such as softness, light-fastness and resistance to heat influence etc. not being impaired.
Accordingly, there is provided a process for producing a leather dressing agent obtained by
A) polymerization of
al) 70-100 wt. % of at least one of(meth)acrylic acid, acid chlorides thereof, and anhydrides
thereof with
a2) 0-30 wt. % of other water-soluble monomers copolymerizable with al), and
a3) 0-20 wt. % of water-insoluble monomers copolymerizable with al) and a2), to form a
polymer,
B) reaction of the polymer from A) with amines of formula R1--NH--R2 wherein
Ri represents a C12-C30 alkyl or alkenyl residue, and
R2 represents H, a C1-C4 alkyl or C1-C2 hydroxyalkyl residue, optionally
C) reaction of the amines not bound to the polymer from A) with (meth)acrylic acid to give N-substituted p-aminopropionic acids and optionally, acylation of the amines not bound to the polymer from A), or the N-substituted P-aminopropionic acids formed,
D) neutralization and dispersion, of, the product obtained from B) and if C) is carried out, of the product obtained from C),
wherein the monomers al), a2) and a3) are subjected to free-radical polymerization, the polymer obtained is then reacted either immediately or subsequent to solvent removal with the amines of formula Ri~NH~R2, wherein R1 and R2 have the above meanings, at least part of acid groups present in the polymer being converted to amide groups, followed by partial or complete neutralization of remaining carboxyl groups using dilute base, optionally with addition of water.

The invention is directed to new leather dressing agents, particularly for car upholstery leather, which may be obtained by
A) Polymerization of
al) 70-;.00 wt.-% acrylic acid and/or methacryiic acid
and/or the acid chlorides and/or anhydrides thereof
with a.2) 0-30 wt.-% of other water-soluble monomers copoiymer-
izable with al), and a3) 0-20 wt.-% of water-insoluble monomers copolymeriza-
ble with al) and a.2),
B) reaction of the polymerizate from A) with amines of
formula I
R1-NH-R2 wherein
R1 represents a C12-C30 alkyl or aikenyl residue, and R2 represents H, a C1-C4 alkyl or c1-C2 hydroxyalkyl residue, optionally
C) reaction of the amines not bound to the polymerizate from A) with (meth)acrylic acid to give N-subst.it.uted 0-aminopropionic acids and optionally, acylation,
D) neutralization and dispersion of the product obtained from B) -and C), respectively.
The invention is also directed to a process for the production of leather dressing agents, characterized in that the monomers al), a2) and a3) are subjected to free-radical. polymerization, preferably in solution, the polymerizate obtained is then reacted either immediately or subsequent to solvent removal with the amines of formula R1-NH-R2, wherein R1 and R2 have the meanings indicated in claim l, at least part of the acid groups present in the polymerizate being converted to the corresponding amide groups,, followed by partial or complete neutralization of the remaining carboxyi groups using dilute base, optionally with addition o£ water.
Step A: Polymerization
The polymerizates are produced by free-radical poly¬merization of 70-100 wt.-%, preferably more than 80 wt.-%, relative to the total batch, of acrylic acid and/or roetha-crylic acid and/or the acid chlorides and/or anhydrides thereof.
To improve the polymerizates with respect to the desired properties in leather treatment, particularly fogging behavior, from 0 to 30 wt.-% of other copolymerizable water-soluble monomers are incorporated by polymerisation.
Examples of suitable monomers of this group are (meth)aery1 amide, (meth)allyl alcohol, hydroxyethyl (meth)-acrylate, :iydroxypropyl (meth)acryiate, hydroxyalkylpoly-ethyleneoxy (meth)acrylate, alkyloxypolyethyleneoxy (mefch)-acrylate, polyethylene glycol monoallyl ether, N-vinylpyrro-lidone, or N-vinylimidazole.Other monomers containing acid groups, such as maieic acid, itaconic acid, vinylsulfonic acid, mett.aliylsu3.fon.ic acid, 2-acrylamido-2-methyipropylsulfonic acid, 4-vinyi-phenyisulfonlc acid, vinylphosphonic acid, as well as the water-soluble esters, anhydrides, alkali, alkaline earth and/or ammonium salts thereof may also be used.
Furthermore, it may be useful to employ basic mono¬mers in ths polymerization, such as dimethylaminoalkyi (meth)acrylate and/or dimethylaminoalkyi fmeth)acrylamide and/or the quaternary forms thereof.
Naturally, the polymerizates of these monomers are highly hydrophilic in character. Therefore, it may be useful to act on hydrophilicity by employing from 0 to 20 wt.-% of one or more monomers from the group of hydrophobic monomers. For example, this group comprises C1-C30 alkyl (meth)acry-lates, vinyl esters of C1-C30 carboxylic acids, vinyl ethers of C1-C30 alcohols, or ethylenically unsaturated aromatic monomers such as styrene.
The polymerization itself may be effected according to the processes of bulk, solution, suspension or emulsion polymerization. The solution polymerization process is pre¬ferred, where the solvent must fulfill the provision of being ablev to dissolve all the monomers employed. Accordingly, water, C1-C4 alcohols and their ethylene oxide adducts, gly¬cols and ketones such as acetone or methyl ethyl ketone are suitable, with higher boiling organic solvents being pre¬ferred due to their more favorable fogging behavior in the final product. It is particularly preferred to use ethylene glycol butyL ether and diethylene glycol butyl ether as sol¬vents in the- polymerization.
The polymerization may be carried out batchwise as well as in continuous operation, using a tank reactor cas¬cade, for example. If the reaction is carried out batchwise,
a feeding procedure is preferred where monomers and initiator are metered into the vessel over a period of several hours at constant teirperature. In addition, however, an adiabatxc operation is also possible, where the monomers are pre charged completely or partially, and the generated polymer¬isation heat results in a temperature rise and a more rapid reaction of -he monomers in the batch.
The initiation of the free-radical polymerization is triggered by common initiators, e.g., by tbtermal or photo¬chemical ly iiduced decomposition of radical-forming peroxide and/or azo compounds and/or by suitable redox systems, the selection of the suitable system depending on the designated reaction temperature and the reaction rate, in adiabatic polymerization of the monomers, it may be useful to employ multiple initiators, e.g., those having different: decomposi¬tion temperatures. As a rule, those systems having sufficient solubility ;in the reaction medium will be preferred. The amount of initiator preferably ranges from 0.01 to l wt.-%, relative to the total of monomers.
The molar weight of the poiymerizates is controlled via reaction conditions and/or by using modifiers such as mercaptans. The amount of modifier preferably ranges from 0 to 5 wt.-%, relative to the total of monomers.
The number average molar weight of the poiymerizates obtained arci between 1,000 and .100,000 g/mole, as determined by gel permeation chromatography.
Reaction temperatures ranging from 20 to 200"C are preferred and optionally, the polymerization may also be performed under pressure. Preferably, the polymerization times are 0.5-8 hours.
The polymerization is either followed by immediate polymer-analogous reaction of the polymerizate according to
step B), or the solvent is separated from the polymerizate first, e.g., by distillation. When polymerizing in aqueous medium, the latter is necessary in order to achieve suffi¬cient conversion in the subsequent reaction of the polymeri¬zate.
Step B; Reaction with fatty amines
in this reaction step according to the invention, part of the DOlymeri2ate acid groups presentis converted to the corresponding amide groups by reaction with fatty amines of formula I:
wherein
Rx represents a C12-C30 alkyl or alkenyl residue, and
R2 represents; H, a C1-C4 alkyl residue or a C1-c2 hydroxyalkyl
residue.
In contrast to the use of fatty alcohols according to DR 42 05 839 Al, significantly improved product stability has been observed when fatty amines were used according to the invention.
The amount of fatty amine employed according to the invention determines the softness degree of the leather. The more«• acid groups of the polymerizate are modified by reaction with one or more fatty amines, the softer the „eather treated therewith. However, since there is an influence on the auto-emuisifiability of the polymer formed, not all of the carbox¬yl groups of the polymerizate should be reacted in this fash¬ion. Reacting an amount of from 20 to 80 mole-% relative to the carboxyl groups present in the polymerizate has proven advantageous in experiments.
In addition to the amount of fatty amine employed, the length of the alkyl chain has an influence on the achiev¬able softness. In general, alkyl chains having 12-30 c atomsprovide good usability of these agents. For especially soft types of leather, fatty amines having a carbon number between 16 and 22 are preferred. Particularly preferred in the poly mer-analogous reaction is the use of oleylamine and stearyi
amine.
The reaction of the polymerizates with the fatty amines is preferably performed in the presence of acid cata¬lysts, e.g., with p-toluenesulfonic acid. The amount of cata¬lyst should not exceed 1 mole-%, based on carboxyi groups present.
The reaction time depends on the desired conversion which may be monitored by thin layer chromatography, for example, anc. should be more than 90%.
The reaction temperature is between 60 and 200°C, a reaction under reduced pressure being advantageous, particu¬larly at lower reaction temperatures. in order to achieve conversions of more than 99%, it may be required to remove the produced reaction water azeotropically.
Step C: Reaction of residual fatty amine to N-substituted ß-aminoprop;onic acids
This optional step is carried out in those cases where a particularly low content of residual amine is re-quired in the final product. Here, the residual amines are reacted with (meth)acrylic acid and optionally, the amines not bound to the polymeri2ate from A) or the produced N-sub-stituted ß-aminopropionic acids are acyiated. The details of this reaction have been described in DE 37 17 961 C2. One advantage of this step is that achieving low amounts of re¬sidual amine during step B is not necessarily required, which is why operation may also be effected using excess fatty amine, i.e., more than 80 mole-%, relative to the carboxyl groups.
Step D! Neutralization and diapers i on
subsequent to the polymer-analogous reaction, the remaining ca::boxyl groups are neutralized partially or com¬pletely, using dilute base, optionally with addition of wa¬ter, the polymeri2ate being dispersed and/or dissolved, suit¬able neutralizing agents are alkali and alkaline earth hy¬droxides, ammonia, amines or aminoalcohols. The amount of base is selected such that a pH value between 5 and 9 is established. The aqueous emulsions accordinq to the invention are adjusted to a solids content of from 20 to 80 wt.-%.
The invention also relates to the use of the agents of the invention in the manufacture of upper leathers having low contents of evaporating volatiles, particularly car up¬holstery leathers.
The agents of the invention which contain these modi tied polymerizates may either be used as such or in combina¬tion with o-her stuffing agents in the manufacture of car upholstery leathers.
in addition to the manufacture of car upholstery leathers, the products of the invention are also suited for manufacturing hydrophobized upper leathers or clothing wash¬able*- leathers. The required amount of the products is from 2 to 20 wt.-%, preferably 5-15 wt.-%, based on the shaving weight of the leather. They are normally employed at the stuffing stage of leather processing.
The following embodiments are intended to illustrate the invention, without limiting the inventive idea. Ail the numerical data in the examples relate to amounts by weight, unless otherwise stated.
Example 1
45.0 g of ethylene glycol butyl ether is placed in a reactor equipped with anchor stirrer, metering units, inter¬nal thermometer and distillation column and heated to about 80°C. Thereafter, the following supplies are started:
Supply 1: 72.0 g (1.0 moles) of acrylic acid Supply 2: 9.0 g (0.1 moles) of mercaptoethanol Supply 3: 0.5 g (3.0 mmoles) of azobisisoQutyronitrile in 15 g of ethylene glycol butyl ether
The metering time is about one hour. Stirring is continued for another 30 minutes at 80'C and subsequently, 58 g (0.22 moles) of oleylamine and 0.4 g of p-toluenesulfo-nic acid are added. The temperature is raised to 150*c, and the batch is; stirred for 4 hours, with 15 g of distillate being withdrawn. After four hours, the batch was checked using thin layer chromatography. A residual amine content of 5%, based or overall product, corresponding to a conversion of about 85% was found. Cooling to about 95"C was effected. Thereafter, 2.0 g of acrylic acid was added, followed by addition of 1.8 g of r.aleic anhydride. Stirring was continued for another hour and eventually, the product was neutralized with 50 g of sodium hydroxide solution (50%) and 350 g of water and dispersed. A clear yellow product was obtained, having about. 35% of dry substance wherein no residual amine could be detected anymore. The pH value was 6.8.
Example 2:
Example 1 was repeated, but 0.5 g of hypophosphorous acid was added as catalyst for the amidation. After the poly-mer-analogov.s amidation, a residual amine content of 0.8% was found and therefore, reaction with acrylic acid and MSA was refrained. A clear yellow product was obtained, having an active substance of 40 wt.-% and a pH value of 6.6.
Example 3:
Example 1 was repeated, but 110 g of oleylamine (0.42 moles) was employed. A yellow emulsion was obtained, having a pH value of 7.5 and an active substance of 40 wt.-%.
Example 4:
This example corresponds to Example 1, but 60 g of a. low-fogging sulfited fish oil was added at xthe end of the reaction. A Light- brown clear solution was obtained, having an active substance of 40% and a pH value of 6.6.
Example 5: Manufacture of a car upholstery leather
(Table Removed)
The leathers are wet-stretched on a horse overnight, dried, wettec, staked and milled.
A low-fogging polymer stuffing agent ;ci: marketed product "Magnopal®" S0F, manufactured by stockhausen GmbH & Co. KG) and a low-fogging stuffing agent based on fish oii3 (C2: marketed product "Chromopol®" LFC, marufactutred by Stockhausen GmbH & Co. KG) were used as comparative examples (state of the art).
Table of results:

(Table Removed)
Notes on the* aoove values:
Softness: assessment according to the (German) school grading
system (1: very good; 6; unsatisfactory)
Fogging, gruvimetrically: data in nig/50 cm2

Light-£astnes According to DIN 54004, assessment using blue standard under daylight lamp, lower figures correspond to stronger yellowing.
The t.able shows that the products of the invention are superior to the prior art products in at least one crite¬rion.




WE CLAIM :
1. A process for producing a leather dressing agent obtained by
A) polymerization of
al) 70-100 wt. % of at least one of (me th) acrylic acid, acid chlorides thereof, and anhydrides thereof with
a2) 0-30 wt. % of other water-soluble monomers copolymerizable with al), and
a3) 0-20 wt. % of water-insoluble monomers copolymerizable with al) and a2), to form a polymer,
B) reaction of the polymer from A) with amines of formula R1--NH--R2
wherein
Ri represents a C12-C30 alkyl or alkenyl residue, and
R2 represents H, a C1-C4 alkyl or C1-C2 hydroxyalkyl residue, optionally
C) reaction of the amines not bound to the polymer from A) with (meth)acrylic acid to give N-substituted P-aminopropionic acids and optionally, acylation of the amines not bound to the polymer from A), or the N-substituted fi-aminopropionic acids formed,
D) neutralization and dispersion, of, the product obtained from B) and if C) is carried out, of the product obtained from C),
wherein the monomers al), a2) and a3) are subjected to free-radical polymerization, the polymer obtained is then reacted either immediately or subsequent to solvent removal with the amines of formula R1--NH--R2, wherein Ri and R2 have the above meanings, at least part of acid groups present in the polymer being converted to amide groups, followed by partial or complete neutralization of remaining carboxyl groups using dilute base, optionally with addition of water.
2. The process as claimed in claim 1, wherein prior to neutralization and dispersion, residual amine is reacted with (meth)acrylic acid and optionally, subsequently acylated.
3. The process as claimed in claim 1, wherein the reaction of the polymer with the amines of formula Ri—NH--R2 is performed at temperatures of from 60 to 200°C, optionally under reduced pressure and/or with azeotropic removal of reaction water produced.
4. The process as claimed in claim 1, wherein neutralization is done by adjusting a pH value of from 5 to 9 is finally adjusted using dilute base, with dispersion or solution of the product.
5. The process as claimed in claim 1, wherein said free-radical polymerization is carried out in solution.
6. The process as claimed in claim 1, wherein the dilute base is selected from the group consisting of alkali and alkaline earth metal hydroxides, ammonia, amines and amino alcohols.
7. The process as claimed in claim 1, whenever utilized in a process of manufacturing of upper leathers with a leather dressing agent, like upholstery leathers.
8. A process substantially as hereinbefore descried with reference to and as illustrated in the foregoing examples.

Documents:

2543-del-1997-abstract.pdf

2543-del-1997-claims.pdf

2543-del-1997-complete-spacition(granted).pdf

2543-del-1997-correspondence-others.pdf

2543-del-1997-correspondence-po.pdf

2543-del-1997-description (complete).pdf

2543-del-1997-form-1.pdf

2543-del-1997-form-13.pdf

2543-del-1997-form-19.pdf

2543-del-1997-form-2.pdf

2543-del-1997-form-3.pdf

2543-del-1997-form-4.pdf

2543-del-1997-form-6.pdf

2543-del-1997-gpa.pdf

2543-del-1997-petition-137.pdf

2543-del-1997-petition-138.pdf


Patent Number 236209
Indian Patent Application Number 2543/DEL/1997
PG Journal Number 42/2009
Publication Date 16-Oct-2009
Grant Date 08-Oct-2009
Date of Filing 08-Sep-1997
Name of Patentee STOCKHAUSEN GMBH& CO.KG
Applicant Address BAKERPFAD 25,47805 KREFELD,GERMANY.
Inventors:
# Inventor's Name Inventor's Address
1 NORBERT BEHLAU KALKSTRASSE 1A, 45468 MULHEIM A.D.RUHR,GERMANY.
2 KURT DAHMAN VON-VELSEN-STRASSE 6,41239 MONCHENGLADBACH,GERMANY.
3 THOMAS MULLER AUGUST-MACKE-WEG 124, 40670 MEERBUSCH,GERMANY.
4 REINMAR PEPPMOLLER ALTE KEMMERHOFSTRASSE 189,47802 KREFELD,GERMANY.
PCT International Classification Number C14C 9/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 196 36 494.9 1996-09-09 Germany