Studies of some basic aspects in easy care cotton finishing I. Nature of substrate and methods of application

1982

Acta Polymerica

Urea oxalate was used as a catalyst for crosslinking of cotton cellulose with various N-methylol finishing agents under a variety of conditions, e.g. concentration of reactants and kind of treatment. It was found that urea oxalate acts as an efficient catalyst for crosslinking. Untersuchungen zur Pflegeleichtausrustung von Baumwolle. Teil V I I . Harnstoffoxalat als Katalysator fur VernelzungsreaktionenHarnstoffoxalat erwies sich als wirksamer Katalysator fur die Vernetzung von Baumwollcellulose mit verschiedenen N-Metliyloles bei unterschiedlichen Bedingungen, z. B: Konzentration der Reagenzien und Art der Bebandlung. Mccm6'oeanuR no necntunaentoc omaeme xaonxa. Vacma V I I . OxcaaamAoueeuml; e xarcecmee xamwuaamopa 6'a. m peanyuii cwueanus OKCaJIaT M09eBNHbI OKa3aJICII 3l$l$eKTMBHbIM KaTaJIH3aTOpOM RJIR CIUHBaHHR XJIOIIKOBOm ~eJIJIIon03bI C pa3HbIMH N-MeTHJIOJIaMM IIpH Pa3JIMqHLJX yCJI0BkiRX (HaIIpSqMep, KOHqeHTPaqHR PeareHTOB M MeTOA O~~~~O T K H ) .

Studies of some basic aspects in easy care cotton finishing. Part VII. Urea oxalate as a catalyst for crosslinking

1982

Acta Polymerica

Studies of some basic aspects in easy‐care cotton finishing, III. Catalysts

Nassar

et al. 1979

Angew. Makromol. Chem.

A balance between wet/dry crease recovery and strength properties could be achieved by treating cotton fabrics with dimethylol dihydroxy ethylene urea (DMDHEU) with a new technique. The latter involves padding with an aqueous solution containing DMDHEU and a specific concentration of an ammonium salt. The ammonium salts examined were: ammonium chloride, ammonium mono‐ and dihydrogen phosphate, ammonium nitrate, ammonium sulphate, ammonium oxalate and ammonium citrate. Of particular interest were the results obtained with fabrics catalyzed by ammonium dihydrogen phosphate. While these fabrics show crease recovery angles of 298° and 304° the loss in tensile strength amounts only to ca. 14%. It was postulated that the catalytic system used is based on two phases; the first is the initial acidity which induces crosslinking in the wet state thus enhancing the wet crease recovery; the second phase involves decomposition of the ammonium salt during curing with generation of acid which catalyzes crosslinking in the dry state thereby improving the dry crease recovery. The relatively lower losses in strength properties suggest that this catalytic system brings about a uniform distribution of crosslinks in the cellulose structure.

Studies of some basic aspects in easy‐care cotton finishing, IV. Effect of acid scavengers on free formaldehyde in and strength of crosslinked cotton

Nassar

et al. 1979

Angew. Makromol. Chem.

When cotton fabric was padded with a solution containing dimethylol dihydroxy ethylene urea (DMDHEU) (200 g/l) at pH 2.5, batched for one hour, given a wash through padding with water, dried and cured, the crosslinked cotton showed a crease recovery of 287" and 307" in the dry and wet state respectively and a retained strength of ca. 68%. Incorporation of sodium hydroxide in the washing pad accentuates the retaining strength. The latter attained a value of ca. 90% without seriously affecting the dry and wet crease recovery. However, the amount of free formaldehyde in the crosslinked cotton was quite substantial. Increasing the concentration of NaOH up to 2 g/l in the washing pad caused a significant decrease in crease recovery of and a considerable increase in the amount of free formaldehyde in the crosslinked cotton fabric. Replacement of sodium hydroxide by sodium carbonate at a concentration of up to 2 g/1 reduced the amount of free formaldehyde without adversely affecting the crease recovery. Utilization of urea in the washing pad at a concentration of up to 16 g/1 provided advantages in terms of lesser amount of free formaldehyde (388 ppm), higher retaining strength (ca. 80%) and excellent crease recovery (above 280"). On the other hand, addition of sodium sulphite at a concentration of up to 8 g/l in the washing pad was accompanied by a significant decrease in crease recovery, and a significant increase in the amount of free formaldehyde. Nevertheless the role of sodium sulphite as acid and formaldehyde scavanger could be ameliorated through lowering the pH of DMDHEU padding bath or addition of sodium chloride or sodium dihydrogen phosphate to this bath. ZUSAMMENFASSUNG:Mit Dimethyloldihydroxyathylenharnstoff (DMDHEU) modifizierte Baumwolle zeigt einen Festigkeitsverlust von ca. 32%, einen Trocken-und NaBknitterwinkel von 287 bzw. 307". Die Verwendung von Natriumhydroxid im waRrigen Bad verringert den Festigkeits- 27