William E. Franklin

Recurable Durable-Press Fabrics Part I : Polycarboxylic Acids as Coreactant Curing Catalysts with N-Methylol Reagents

Polycarbcxylic acids having three or more carboxyl groups per molecule were used as coreactant curing catalysts with a series of N-methylol crosslinking agents. Strongly acidic, water-soluble acids were found to be effective catalysts for the curing reactions, while less soluble or weaker acids were poor catalysts, as were partially neutralized polycarhoxylic acids. The X-methylol crosslinking agents which responded most favorably to catalysis by the carboxylic acids were those which formed ethers that were most stable to acid-catalyzed hydrolysis. The N-methylol crosslinking reagents which formed ethers less stable to acidic hydrolysis gave poor wrinkle recovery angles when applied to cotton fabrics with carboxylic acid catalysts.

Mechanistic Aspects of Flame Retardancy in Cotton Cellulose

A series of cotton fabrics treated with different levels of THPOH-NH3 was examined by pyrolysis-mass-spectrometry and thermogravimetry. Small amounts of THPOH NH3 lowered the pyrolysis temperature and increased the char yield, but larger amounts of the flame retardant effected little additional change. Identical kinetic parameters character ized the formation of all cellulose pyrolysis products from a given fabric; these parameters were very similar for all the treated fabrics. Small amounts of THPOH-NH 3 greatly decreased the fractions of anhydroglucoses (levoglucosan, 1,6-anhydroglucofuranose, and 1,4:3,6-dianhydroglucopyranose) in the volatile pyrolysis products but increased the fractions of furans (hydroxymethylfurfural, furyl hydroxymethyl ketone, and levoglucosenone). Larger amounts of THPOH-NH 3 decreased the furan fractions. Add-on of flame retardant had relatively little effect on fractions of carbon dioxide and carbon monoxide. The water fraction increased continuously with add-on to a maximum at 21% of THPOH-NH 3. Flammability (oxygen index) was closely correlated with the molar fraction of nonfuels (water and carbon dioxide) in the volatile products. Mechanisms of flame retardancy are discussed.

Recurable Durable-Press Fabrics Part II: Recurability of Fabrics Treated with Methylol Reagents and Polycarboxylic Acids

A recurability test, consisting of a standard ironing to impart a crease, followed by laundering and visual rating of the remaining crease, was developed and applied to cotton fabrics which had been treated with combinations of a methylol crosslinking reagent and a polycarboxylic acid. These fabrics were recurable to a much greater extent than fabrics treated with a conventional metal salt catalyst. A series of ten methylol reagents, when used with polycarboxylic acids, showed a direct relationship between recurability and wrinkle-recovery angle in the treated fabrics. Dimethyloidihydro xyethyleneurea was the best of these reagents in both respects.

Recurable Durable-Press Fabrics Part IV : Hydroxy Acids with N-Methylol Reagents for Producing Recurable Durable-Press Fabrics1

Hydroxy acids were used as coreactant catalysts with N-methylol crosslinking reagents to produce recurable durable-press cotton fabrics. The resilience and strength retention properties of these fabrics were equivalent to or slightly better than those of durable-press fabrics cured with a conventional curing catalyst. All fabrics tested with gluconic acid had low carboxyl contents, whereas fabrics treated with glycolic, lactic, and tartaric acids had carboxyl contents that varied with the methylol reagent. The recurabilities of these fabrics were measured by a creasing and crease durability test. Fabrics cured with a conventional catalyst and the fabrics cured with gluconic acid had very little or no recurability. Fabrics treated with dimethyloldihyroxyethyleneurea and the other hydroxy acids had excellent recurabilities. Fabrics treated with a urea-formaldehyde regent had poor recurabilities, and those treated with a methylol melamine reagent had good to fair recurabilities.

Recurable Durable-Press Fabrics Part III : Textile, Chemical, and Recuring Properties of Fabrics Treated with DMDHEU and Polycarboxylic Acids

Cotton twill fabric was treated by a pad-dry-cure process with combinations of DMDHEU and several potycarboxytic acids. Fabrics were prepared with several ratios of catalytic rarhoxylic acid groups to DHEU residues in the modified cellulose. The wrinkle-recovery angles, durable-press appearance ratings, and strength retentions of these fabrics were equivalent to or slightly better than those imparted by the conventional DMDHEU-MgCl2 treatment. The fabrics were analyzed for nitrogen, formaldehyde, ester linkages, and free carboxytic acid groups. The ratios of formaldehyde residues to DHEU residues in the cured experimental fabrics decrease with increasing wrinkle-recovery angles of the fabric. These fabrics showed very good recurahility when prepared with selected polycartroxylic acids, e.g., citric, cyctopentanetetra cartroxylic, and tetrahydrofurantetracarboxylic acids. The rerurahility was lost by converting the free carboxyl groups in the fabric to salt forms, but was restored when the free carboxyl groups were regenerated.

Reversible Crease Formation in Cotton Cellulose Dicyclopentadienedicarboxylate Fabrics

Cotton cellulose fabric was reacted with dicyclopentadienedicarboxylic acid and with dicyclopentadienemonocarboxylic acid in the presence of trifluoroacetic anhydride. The fabric cross-linked with dicyclopentadienedicarboxylic acid had wrinkle recovery angles of 223° (wet) and 191° (conditioned). The wet and conditioned wrinkled recovery angles increased to 274° and 264° when the fabric was heated. Sharp creases were obtained when the fabric was held in a folded position and heated at 145 to 160°C for 15 min or more. These creases were durable to ironing, but could be removed by heating the fabric for extended periods while it was held in a flat position. This reversible crease formation is believed to result from the reversible dissociation and rearrangement of the cross links at high temperatures. When cotton cellulose dicyclopentadienemonocarboxylate fabric was heated at 160°C for two hours, it developed high wrinkle recovery and retained sharp creases as a result of the dissociation of the substituent groups and the recombination of the cyclopentadienecarboxylate groups remaining on the cellulose.

Amic Acids and Half Salts of Dicarboxylic Acids as Coreactant Catalysts for Creasable Durable-Press Fabrics

Amic acids and half salts derived from 1,2,- or 1,3-dicarboxylic acids were used with methylol reagents as coreactant curing catalysts to produce durable-press cotton fabrics by a pad-cure process. Maleamic acid (derived from malcic anhydride and ammonia) and the monosodium, ammonium, and potassium salts of maleic acid, when used with DMDIIEU, generated the highest levels of wrinkle recovery. The formation of permanent creases in these fully cured fabrics, which also had a strong affinity for basic dyes, is discussed.

Recurability and Textile Properties of Postactivated Cotton and Blend Fabrics

Cotton and cotton-polyester blend fabrics were finished by a dimethyloldihydroxyethyleneurea (DMDHEU)-glycolic acid-postactivation process to give fully-cured durable-press fabrics which could be given sharp, permanent creases by an ironing process. The resilience and strength-retention properties of these fabrics were equivalent to, or slightly better, than those of corresponding cotton or blend fabrics which had been finished by conventional durable-press processes. The postactivated blend fabrics accepted better creases at low temperatures than the corresponding cotton fabrics, but at the moderately higher temperatures required to form acceptable permanent creases, the creasabilities of the cotton and blend fabrics were almost equivalent. Unmodified blend fabrics and conventionally finished durable-press blend fabrics, either postactivated or not activated, accepted better permanent creases than the corresponding cotton fabrics, but none of these creases were acceptable.

Postactivation Catalysts for Recurability of DMDHEU-Glycolic Acid Durable-Press Fabrics

Potential postactivation catalysts for promoting the recurability of durable-press cotton fabrics that have been finished with DMDHEU and glycolic acid were studied to find optimum catalysis and creasing conditions for these fabrics. A thorough study was made of the effects of concentration and creasing temperature in postactivation catalysis with magnesium chloride and zinc nitrate. The catalytic activity of other potential metal salt catalysts was surveyed, and the effects on catalytic activity of divalent, trivalent, and tetravalent metal cations and various anions were measured. Several phase-separation catalysts were studied as postactivation catalysts.

Characteristics of Internally Buffered N-Methylol Reagents and Their Reactions with Cotton

Two t-amino-N-methylol reagents, 2(diethylamino)ethyl N,N-di(hydroxymethvl)carl)amate and dimethyloldi ethylaminopropyltriazone, were prepared, and their reactivities in finishing of cotton fabrics were characterized. Auto- catalysis was shown by these reagents when they were applied as hydrochlorides to cotton fabric and given a conventional pad-dry-cure; however, full development of resilience was not realized unless the pH of the reagent solution was lowered to 1.0. The sluggish reactions of the t-amino-N-methylol reagents are discussed; the stronger-than-normal catalysis that was required counterbalanced potential protective effects from the t-amino groups to lessen acid degradation during finishing reactions.