AU9341098A

AU9341098A - Nonfelting wool and self-dispersing isocyanates therefor

Info

Publication number: AU9341098A
Application number: AU93410/98A
Authority: AU
Inventors: Bernhard Jansen; Ferdinand Kummeler; Helga Thomas
Original assignee: Bayer AG
Current assignee: Bayer AG
Priority date: 1997-08-22
Filing date: 1998-08-11
Publication date: 1999-03-16
Anticipated expiration: 2018-08-11
Also published as: JP2001514341A; AU730514B2; WO1999010590A1; DE19736542A1; EP1005584A1

Description

- 1 Nonfelting wool and self-dispersing isocyanates therefor The invention relates to nonfelting wool, to a process for producing it by a) a 5 pretreatment with a low pressure plasma and b) an aftertreatment with aqueous dispersions of self-dispersing isocyanates, and also to water-dispersible isocyanates useful for this purpose. Isocyanates for the antifelt finishing of textiles are well known and can be used, for 10 example, as described in DE-A-1,904,802, in organic solvents or, as described in DE A-1,769,121, in aqueous dispersion with the aid of emulsifiers. Both organic solvents and possibly water-polluting emulsifiers are today no longer appropriate for ecological and occupational hygiene reasons. In what follows, therefore, either the isocyanates referred to will be self-dispersing or the formulations referred to will 15 contain little if any solvents or emulsifiers as auxiliaries and additives. FR 1,542,831 describes the treatment of textile materials with baths which contain polymers or copolymers of vinyl or divinyl compounds, an aqueous dispersion of isocyanates, ammonium salts or metal salts and surfactants. Auxiliary solvents are 20 employed. DE-A-1,794,221 describes the treatment of fiber materials with isocyanate prepolymers which still contain free isocyanate groups; this finishing process can take place in solvents (perchloroethylene) or in aqueous emulsion by using auxiliary emulsifiers. US-P 3,847,543 discloses a process for the antifelt finishing of wool using an aqueous dispersion containing the following ingredients at one and the same 25 time: aliphatic isocyanates, OH-functional crosslinkers and organometallic catalysts. Although this process takes place in aqueous solutions, auxiliary solvents and emulsifiers continue to be required. DE-A 4,415,451 (WO 95/30045) describes a process utilizing water-dispersible isocyanates for the antifelt finishing of wool. No solvents or emulsifiers are needed because the isocyanates used are water-dispersible. 30 However, the process described therein is exemplified as first subjecting the wool to a pretreatment with oxidizing agents, followed by a reductive treatment, before the water-dispersible isocyanates are used. This pretreatment naturally gives rise to -2 wastewaters which have to be properly neutralized and treated. What is more, these isocyanates possess only limited stability in storage. In complete contradistinction thereto, the present invention does not generate any 5 wastewaters whatsoever owing to the low pressure plasma pretreatment and must be given a favorable ecological assessment. This is because it was found, surprisingly, that there is no need for oxidative and/or reducing pretreatment agents to obtain a very good antifelt finish on wool when the treatment with aqueously dispersed isocyanates is preceded by a low pressure plasma treatment. 10 The present invention accordingly provides nonfelting wool, characterized in that dyed or undyed wool slubbing a) is exposed to a low pressure plasma in a pretreatment, and 15 b) aftertreated with aqueous dispersions of self-dispersing isocyanates. The present invention further provides a process for the antifelt finishing of wool, characterized in that dyed or undyed wool slubbing 20 a) is exposed to a low pressure plasma in a pretreatment, and b) aftertreated with aqueous dispersions of self-dispersing isocyanates. 25 The self-dispersing isocyanates likewise form part of the subject-matter of the invention; they have an isocyanate content of 1 to 25% by weight, reckoned as NCO of molecular weight 42 and based on the total weight of the isocyanates, and are obtainable by reaction in any order of: 30 I) organic polyisocyanates having an average NCO functionality of 1.8 to 4.2 with II) polyalkylene oxide alcohols, amines and/or thiols of the formula R N-(CHX-CHY-0),-CHX-CHY-ZH 5 R/ (I), where n is from 3 to 70, 10 X and Y are hydrogen or methyl with the proviso that in the case of methyl only one of X and Y is methyl and the other is hydrogen, 15 R 1 and R 2 are independently straight-chain or branched C -C 6 -alkyl or

CI-C

6 -acyl, although if RI is acyl, R 2 can also be hydrogen, and, furthermore, RI and R 2 may combine to form tetramethylene, pentamethylene or hexamethylene wherein one or two methylene groups can be replaced by 0 and/or NH 20 and/or one or two methylene groups can be substituted by methyl, and Z is 0, S or NH, 25 and also optionally with III) further NCO-reactive compounds containing anionic or cationic or potentially anionic or cationic groups.

-4 For the purposes of the present invention, "self-dispersing" means that the mixtures produce fine dispersions having particle sizes of <500 nm (measured by ultracentrifuge) in water when in a concentration of up to 70% by weight, preferably up to 50% by weight. 5 Examples of useful starting materials for the self-dispersing isocyanates are: I) Unmodified, aliphatic, cycloaliphatic, araliphatic or aromatic isocyanates having an NCO functionality of 1.8 to 4.2. Preference is given to using 10 aliphatic and also cycloaliphatic polyisocyanates which have uretdione and/or isocyanurate and/or allophanate and/or biuret and/or oxadiazine structures and which are preparable from aliphatic, cycloaliphatic, araliphatic or aromatic diisocyanates in a conventional manner. Suitable examples are 1,4 diisocyanatobutane, 1,6-diisocyanatohexane, 1,5-diisocyanato-2,2 15 dimethylpentane, 2,2,4- and 2,4,4-trimethyl-1,6-diisocyanatohexane, 1,3- and 1,4-diisocyanatocylohexane, 1 -isocyanato-3,3,5-trimethyl-5 isocyanatomethylcyclohexane, 1 -isocyanato- 1 -methyl-4-isocyanatomethyl cyclohexane and 4,4-diisocyanatodicyclohexylmethane or any mixtures of such diisocyanates. 20 The preferred reaction products of these diisocyanates, which contain uretdione, isocyanurate, allophanate, oxadiazine groups are polyisocyanate mixtures having an NCO content of 19 to 24% by weight which consist, essentially of trimeric 1,6-diisocyanatohexane or 1-isocyanato-3,3,5 25 trimethyl-5-isocyanatomethylcyclohexane and of the corresponding higher homologs and contain isocyanurate groups and optionally uretdione groups. Particular preference is given to using the corresponding polyisocyanates of the mentioned NCO content which are substantially free of uretdione groups and have isocyanate groups and which are obtainable by conventional, 30 catalytic trimerization of 1,6-diisocyanatohexane or 1-isocyanato-3,3,5-tri methyl-5-isocyanatomethyl-cyclohexane by isocyanurate formation and which preferably have an (average) NCO functionality of 3.2 to 4.2. Preference is 41 -5 also given to the trimeric polyisocyanates having an NCO content of 19 to 24% by weight which are obtained in a conventional manner by reaction of 1,6-diisocyanatohexane with a deficiency of water and which have essentially biuret groups. 5 Further suitable polyisocyanates are aliphatic or aromatic diisocyanates such as hexamethylene diisocyanate, toluylene diisocyanate, 1,5-diisocyanato naphthalene, diphenylmethane diisocyanate and their higher homologs with uretdione, isocyanurate, allophanate and also biuret groups. 10 II) Of the polyalkylene oxide ether alcohols, ether amines and/or ether thiols of the formula (I), the polyalkylene oxide ether alcohols are preferred. The polyalkylene oxide ether alcohols are mono- or polyhydric polyalkylene 15 oxide ether alcohols which contain on average 3 to 70, preferably 6 to 60, alkylene oxide units per molecule and as are obtainable in a conventional manner by alkylation of suitable starter molecules. These polyalkylene oxide ether alcohols can be prepared using any desired secondary amines or acid amides as starter molecules. Also suitable for the alkoxylation reaction are 20 heterocyclic nitrogen compounds such as morpholine, for example. Identical compounds are likewise obtainable by using morpholinoethanol as starter for the ethoxylation reaction. Further useful starters include, for example, acylation products of ethanolamine such as acetylethanolamine, for example. Alkylene oxides suitable for the alkoxylation reaction are ethylene oxide and 25 propylene oxide, which can be used in the alkoxylation reaction individually or in any desired order or else mixed. The polyalkylene oxide ether alcohols are either pure polyethylene oxide polyethers, pure polypropylene polyethers or mixed polyalkylene oxide 30 polyethers which have at least one polyether sequence which possess at least 3, generally 3 to 70, preferably 6 to 60, particularly preferably 7 to 20, alkylene oxide units and not less than 60 mol%, preferably not less than -6 70 mol%, of whose alkylene oxide units consist of ethylene oxide units. Preferred such polyalkylene oxide polyether alcohols are monofunctional polyalkylene oxide polyethers started on an aliphatic nitrogenous starter as per structure (I) and containing 6 to 60 ethylene oxide units on average. 5 The ether alcohols can be reacted with H 2 S to prepare ether thiols (Z=S) and with NH 3 to prepare ether amines (Z=NH). III. The further NCO-reactive compounds which contain anionic or cationic 10 and/or potentially anionic or cationic groups are: i) Hydroxyl-functional or amino-functional compounds having tertiary amino groups as extensively described in DE-A-4,319,571; 15 ii) hydroxyl-functional or amino-functional compounds having carboxyl or sulfonic acid groups as extensively described in DE-19,520,092; iii) hydroxyl-functional or amino-functional compounds having carboxylate or sulfonate groups whose counterions are metal cations 20 of the alkali or alkaline earth metal group or ammonium, as extensively described in DE 19,520,092; iv) hydroxyl-functional or amino-functional compounds having ammonium ions which are obtainable in a conventional manner from 25 the tertiary amino groups of the compounds i) by alkylation or protonation as described in EP-A 0,582,166. For the purposes of the invention, it is of course also possible to use any desired mixtures of NCO-reactive groups, if chemically sensible, for example of the groups i) 30 and iv), obtainable for example by partial alkylation of tertiary amino groups, or for example of the groups ii) and iv).

-7 The unmodified polyisocyanates to be used according to the invention can also be used in combination with external ionic or nonionic emulsifiers. Such emulsifiers are described for example in Methoden der Organischen Chemie, Houben-Weyl, vol. 5 XIV/1, part 1, page 190-208 Thieme-Verlag, Stuttgart (1961), in US Patent 3,428,592 and EP-A 0,013,112. The emulsifiers are used in an amount sufficient to ensure dispersibility. If initially polyisocyanates I are reacted with polyalkylene oxide polyether alcohols, this reaction can be carried out in a conventional manner, by maintaining an NCO/OH equivalents ratio of at least 2:1, generally of 4:1 to about 10 1000:1, to obtain polyether-modified polyisocyanates having an average NCO functionality of from 1.8 to 4.2, preferably of 2.0 to 4.0, containing 12.0 to 21.5% by weight of aliphatically or cycloaliphatically attached isocyanate groups and containing 2 to 20% by weight of internal ethylene oxide units (reckoned as C 2

H

4 0, molecular weight = 44 g/mol) in the polyether chains, the polyether chains having on 15 average 3 to 70 ethylene oxide unit. The starting components can be reacted in any desired order in the absence of moisture, preferably without solvent. An increasing amount of component (II) will lead to a higher end-product viscosity, so that it is possible in certain cases (when the 20 viscosity rises markedly) to add a solvent which is preferably miscible with water but inert toward the polyisocyanate. Suitable solvents of this kind are alkyl ether acetates, glycol diesters, toluene, carboxylic esters, acetone, methyl ethyl ketone, tetrahydrofuran and dimethylformamide. 25 Conventional catalysts such as dibutyltin dilaurate, tin(II) octoate or 1,4 diazabicyclo[2,2,2]octane in amounts of 10 to 1000 ppm, based on the reaction components, can be used to speed up the reaction. The reaction is carried out in the temperature range up to 130*C, preferably in the range between 10*C and 100*C, particularly preferably between 20*C and 80*C. The reaction is monitored by titration 30 of the NCO content or by measurement of the IR spectra and evaluation of the NCO band at 2260-2275 cm-1 and is terminated when the isocyanate content is not more than 0.1% by weight above the value which is obtained at complete conversion under

-T/

-8 the given stoichiometry. In general, reaction times of less than 24 hours are sufficient. Preference is given to the solvent-free synthesis of the polyisocyanates to be used according to the invention. 5 In a further embodiment, it is also possible to prepare the polyisocyanate mixtures to be used according to the invention by mixing 1) unmodified polyisocyanates I) 10 2) polyisocyanates obtained by reaction of polyisocyanates I) with the NCO reactive compounds mentioned under III) at an equivalents ratio of the isocyanate-reactive groups of Ill) to the NCO groups of component II, which are used within the range 1:1 to 1:1000, and 15 3) polyisocyanates obtained by reaction of polyisocyanates I) with polyalkylene oxide polyether alcohols, amines and/or thiols II), at an equivalents ratio of the isocyanate-reactive groups of component II to the NCO groups of component I) which are used within the range 1:1 to 1:1000. 20 The person skilled in the art must make use of appropriate initial weights to control the number of the NCO-reactive equivalents of polyether content, the NCO content and the NCO functionality in such a way that the mixture obtained has the composition required for water dispersibility, subject in particular to the preferred ranges already mentioned. 25 The self-dispersible polyisocyanate mixtures are industrially readily handleable and stable for many months in storage in the absence of moisture. This stability is an advantage over prior art materials. 30 According to the invention, the self-dispersible polyisocyanate mixtures are preferably used without organic solvents. They are very easy to emulsify in water at temperatures up to 100*C. The active ingredient content of the emulsion can be up to -T4 -9 70% by weight. However, it is more advantageous to prepare emulsions having an active ingredient content of 1 to 50% by weight, which can then be optionally further diluted upstream of the metering station. Emulsification may be accomplished using the mixing assemblies customary in the art (stirrers, mixers of the rotor-stator type 5 and, for example, high pressure emulsifying machines). The preferred self-dispersible polyisocyanates are self-emulsifying, i.e., they are easy to emulsify without the action of high shearing forces after addition to the water phase. In general, a static mixer is sufficient. The emulsions obtained have a 10 processing time of up to 24 hours, which depends on the structure of the polyisocyanates to be used according to the invention, in particular on their content of basic nitrogen atoms. ,I A4 - 10 Examples A) Self-dispersing isocyanates 5 Self-dispersing isocyanate 1 (comparative): 85 parts by weight of an isocyanate having an NCO content of 22.5% and consisting essentially of trimeric hexamethylene diisocyanate were reacted at 60*C with 15 parts by weight of polyethylene glycol monomethyl ether having an average molecular 10 weight of 350. The resultant product had an NCO content of 17% and a viscosity of 1500 mPas at 25'C. The product was very efficiently dispersible in a glass beaker with water by simply stirring with a glass rod. Arithmetic NCO functionality: F 2.70. 15 Self-dispersing isocyanate 2 (inventive): 85 parts by weight of an isocyanate having an NCO content of 22.5% and consisting essentially of trimeric hexamethylene diisocyanate were reacted at 60*C with 15 parts by weight of an ethylene oxide polyether started on morpholine and having an 20 average molecular weight of 420. The resultant product had an NCO content of 16.5% and a viscosity of 2550 mPas at 25*C. Arithmetic NCO functionality: F = 2.76. Self-dispersing isocyanate 3 (inventive): 25 65 parts by weight of an isocyanate having an isocyanate content of 22.5% and consisting essentially of trimeric hexamethylene diisocyanate were reacted at 60*C with 35 parts by weight of an ethylene oxide polyether started on morpholine and described above. The product had an NCO content of 10.9% and a viscosity of 4400 30 mPas at 25*C. Arithmetic NCO functionality: F = 2.52. ~RA4 - 11 Self-dispersing isocyanate 4 (inventive): 50 parts by weight of an isocyanate having an isocyanate content of 22.5% and consisting essentially of trimeric hexamethylene diisocyanate were reacted at 60*C 5 with 50 parts by weight of an above-described, morpholine-started ethylene oxide polyether. The product had an NCO content of 6.2% and a viscosity of 7080 mPas at 25'C. Arithmetic NCO functionality: F = 1.84. Self-dispersing isocyanate 5 (comparative) 10 60 parts by weight of an isocyanate having an NCO content of 22.2%, prepared by trimerization of 1,6-diisocyanatohexane and consisting essentially of tris(6 isocyanatohexyl) isocyanurate which had an average NCO functionality of about 3.3 were heated to 50*C. 10 g of a methanol-started polyethylene oxide polyether having 15 a molecular weight of 500 and heated to 50*C were added. After heating to 11 0*C, the batch was stirred for 1 hour. Then 0.79 g of dimethylethanolamine were added and stirred in over a further hour. A clear resin was obtained with an NCO content of 15.0%. 20 The self-dispersing isocyanates of the invention were likewise very efficiently dispersible in a glass beaker with water using a glass rod. B) Antifelt finishing tests 25 To compare the isocyanates for utility in antifelt finishing, moist wool slubbing was, as described in DE 19 616 776, subjected to a plasma treatment and then treated by the exhaust method with a buffered aqueous dispersion of the self-dispersing isocyanates described above under A). The wool slubbing after rinsing and drying was tested by the Aachen felting ball test of IWTO 20-69. To this end, a slubbing 30 sample was subjected to felt-forming conditions; the diameter of the resulting ball is a measure of the felting tendency of the finished wool samples (the larger, the better). 5

RZ.

- 12 The results are discernible from the following table: Self-dispersing Average felting ball Comments isocyanate No. diameter 5 1 2.621 comparative 2 2.483 inventive 3 2.767 " 4 2.578 " 10 C) Storage stability tests Storage stability was examined by preparing one kg of each of the self-dispersing isocyanates 2 (inventive) and 5 (comparative) and transferring them to 11 small 15 bottles having a capacity of 100 ml each. After a starting value had been determined not only for the isocyanate content but also for the viscosity, these bottles were stored in a drying cabinet temperature-controlled to 60'C. Storage stability was tested by measuring the isocyanate content and the viscosity at weekly intervals, (the last two measurements were carried out at biweekly intervals); a decreasing NCO content and 20 an increasing viscosity are evidence of secondary reactions in the stored samples. In each case, fresh bottles were opened, so that it was possible to exclude any influence on the test through moisture in the air getting in during repeated opening and resealing. Samples already tested were subsequently discarded. The following table provides an overview of the values found: .4/1 Week self-dispersing isocyanate 2 (inventive) 5 (comparative) Viscosity NCO content Viscosity NCO content [mPas] [%] [mPas] [%] (initial 2620 17.3 9116 15.1 value) 1 2700 17.3 10230 14.5 2 2760 17.2 13520 13.9 3 2760 17.0 18245 13.8 4 2880 16.9 29200 13.0 5 2790 16.9 70612 11.6 6 2910 17.0 177510 11.2 7 3000 17.0 no further values measured 8 3050 17.0 ,, 10 3000 17.0 ,, 12 3000 17.0 ,, This remarkably sensitive test convincingly demonstrated the greatly superior storage stability of the self-dispersing isocyanate 2 of the invention. This is astonishing to a 5 person skilled in the art, since the tertiary nitrogen content of the self-dispersing isocyanate 2 according to the invention is significantly higher than that of the comparative self-dispersing isocyanate 5.

Claims

1. Nonfelting wool, characterized in that dyed or undyed wool slubbing 5 a) is exposed to a low pressure plasma in a pretreatment, and b) aftertreated with aqueous dispersions of self-dispersing isocyanates.

2. Nonfelting wool according to Claim 1, characterized in that the self 10 dispersing isocyanates used for aftertreating have an isocyanate content of 1 to 25%, reckoned as NCO of molecular weight 42 and based on the total weight of the isocyanates, and are obtainable by reaction in any order of I) organic polyisocyanates having an average NCO functionality of 1.8 to 15 4.2 with II) polyalkylene oxide alcohols, amines and/or thiols of the formula R N-(CHX-CHY-0),-CHX-CHY-ZH 20 R2 (I), where n is from 3 to 70, 25 X and Y are hydrogen or methyl with the proviso that in the case of methyl only one of X and Y is methyl and the other is hydrogen, - 15 R I and R 2 are independently straight-chain or branched C1-C 6 -alkyl or CI-C 6 -acyl, although if RI is acyl, R 2 can also be hydrogen, and, furthermore, RI and R 2 may combine to form tetramethylene, pentamethylene or hexamethylene wherein one 5 or two methylene groups can be replaced by 0 and/or NH and/or one or two methylene groups can be substituted by methyl, and Z is 0, S or NH, 10 and also optionally with III) further NCO-reactive compounds containing anionic or cationic or potentially anionic or cationic groups. 15

3. Self-dispersing isocyanates having an isocyanate content of 1 to 25%, reckoned as NCO of molecular weight 42 and based on the total weight of the isocyanates, and are obtainable by reaction in any order of 20 I) organic polyisocyanates having an average NCO functionality of 1.8 to

4.2 with II) polyalkylene oxide alcohols, amines and/or thiols of the formula 25 R N-(CHX-CHY-0),-CHX-CHY-ZH where -9Z/1; 4U -16 n is from 3 to 70, X and Y are hydrogen or methyl with the proviso that in the case of methyl only one of X and Y is methyl and the other is 5 hydrogen, R I and R 2 are independently straight-chain or branched CI-C 6 -alkyl or C 1 -C 6 -acyl, although if R 1 is acyl, R 2 can also be hydrogen, and, furthermore, R 1 and R 2 may combine to form 10 tetramethylene, pentamethylene or hexamethylene wherein one or two methylene groups can be replaced by 0 and/or NH and/or one or two methylene groups can be substituted by methyl, and 15 Z is 0, S or NH, and also optionally with III) further NCO-reactive compounds containing anionic or cationic or 20 potentially anionic or cationic groups. 4. Nonfelting wool according to Claim 2, characterized in that the organic polyisocyanates I) are aliphatic, cycloaliphatic, araliphatic or aromatic isocyanates. 25

5. Nonfelting wool according to Claim 2, characterized in that the polyalkylene oxide alcohols, amines and/or thiols II) have polyether chains of an average molecular weight of up to 3500 (number average) and these polyether chains are constructed of alkylene oxide units. 30

6. Nonfelting wool according to Claim 2, characterized in that the NCO-reactive compounds III) have hydroxyl, amino and/or mercapto groups and may -.17 -. additionally contain tertiary amino groups or their protonated or alkylated variants or carboxyl groups and/or sulfonic acid groups or carboxylate or sulfonate groups obtained by salt formation. 5

7. Process for the antifelt finishing of wool, characterized in that dyed or undyed wool subbing a) is exposed to a low pressure plasma in a pretreatment, and 10 b) aftertreated with aqueous dispersions of self-dispersing isocyanates.

8. Process for the antifelt finishing of wool according to Claim 7, characterized in that the aftertreatment b) of the dyed or undyed wool subbing pretreated in process step a) is effected batchwise in an exhaust process or continuously by 15 dipping, roll application, padding, or by application of a mist or spray.