Wet Wrinkle Recovery Angles Research Articles

An eco-friendly – novel approach for attaining wrinkle – free/soft-hand cotton fabric

A novel approach for upgrading both the wrinkle free and softness properties of cotton fabrics without adversely affecting their strength properties using an eco-friendly finishing regimes was investigated. Factors affecting the performance properties of the finished substrate such as pre-treatment, i.e., carboxymethylation (CMC) or ionic-crosslinking, post-treatment with amino functional silicone softener and its concentration, degree of carboxymethylation as well as thermofixation conditions were studied. The obtained results revealed that post-treatment with the amino based silicone micro emulsion (SiE) up to 30 g/L at pH 4 to a wet pickup of 100% followed by drying at 100 °C for 5 min and curing at 170 °C for 3 min results in a remarkable improvement in fabric resiliency (expressed as dry and wet wrinkle recovery angles), as well as in softness degree, without seriously affecting its retained strength. Improvement extent of the aforementioned properties is governed by the nature of the pre-treatment steps. Fixation of the amino-functional silicone softener onto/or within the modified cellulose structure is accompanied by a formation of semi-inter and/or intra-penetrated network (semi-IPN) thereby enhancing both the extent of crosslinking and networking as well as providing very high softness. FTIR analysis proved the formation of Si–O–Si–cellulose complex. Scanning electron micrograph shows that cotton, CMC and ionic crosslinked cotton fabrics treated with SiE shows higher surface smoothness and considerable reduction in protruding loose fibers, ditches and grooves compared with the untreated one.

Cationization of Linen Fabric: Studying the Process Parameters

Mill scoured and bleached linen fabrics were cationized using Quat-188. Cationization was carried out as per the exhaustion or the cold pad-batch technique under a variety of conditions. Factors affecting the cationization reaction of linen fabric were studied. These factors include Quat-188 concentration, NaOH concentration (or pH of the reaction medium in case of exhaustion method), reaction time and temperature as well as material to liquor ratio (in case of exhaustion method). The cationized samples were monitored for nitrogen content, and the reaction efficiency calculated thereof, as well as for K/S of the no-salt dyed samples. Results obtained indicate that the efficiency of cationization of linen fabric with Quat-188 depends on the type of application technique and the conditions used in each technique. Using the exhaustion technique, maximum reaction efficiency between Quat-188 and linen fabric was achieved at Quat-188, 80 g/1 and pH, 13 and 70°C for 60 minutes using material to liquor ratio, 1:20. Lower material to liquor ratio was not practically possible. The results also depict that any deviation from these conditions, for example, higher pH, temperature or material to liquor ratio, leads to an increase in the hydrolysis of Quat-188 molecules and hence, lower reaction efficiency. With the cold pad-batch technique, maximum reaction efficiency was achieved when the linen fabric was padded in a solution containing NaOH, 50 g/1 and Quat-188, 125 g/1, then squeezed to a wet pickup of 100% and batched for 15 hours. Results obtained also signify that both dry and wet wrinkle recovery angles increase as the degree of cationization (expressed as N % of cationized linen fabric) increases. Moreover, the tensile strength of cationized linen fabric is higher than that of uncationized linen and such an increase depends on the degree of cationization.

Effect of Synthappret BAP on the Wrinkle Recovery of Uncrosslinked and Crosslinked Cotton

The dry and wet wrinkle recovery angles of a cotton fabric are increased by treatment with the carbamoyl sulphonate-terminated poly(ether) urethane, Synthap pret BAP. This product cures best under alkaline conditions, but in the presence of an organometallic catalyst, it can also be cured under the acid conditions used to crosslink cotton with dimethyloldihydroxyethylene urea (DMDHEU). Synthappret BAP improves wrinkle recovery by decreasing the frictional component of wrinkling, probably through the formation of interfiber and interyam bonds. This contrasts with DMDHEU, which acts largely by changing the viscoelastic properties of the fibers. When the treatments are done separately, the improvements obtained with the elastomer and fiber crosslinker are additive for both dry and wet wrinkle recovery. Even better results are obtained however, when the treatment with Synthappret BAP, DMDHEU, and magnesium chloride catalyst is done from a single bath, provided a nonionic surfactant is present. The surfactant is necessary to prevent precipitation of the magnesium salt of Synthappret BAP. The practical significance of these results is that fabrics with dry and wet wrinkle recovery angles similar to those produced by treatment with a high level of DMDHEU alone can be produced by a pad-dry-cure method, using low concentra tions of Synthappret BAP (<1.0% solids omf) plus DMDHEU (1-2% solids omf). These fabrics have better abrasion resistance and tear and tensile strengths than fabrics treated solely with a high level of the crosslinker.

Wrinkle-Resistant Cotton by Photo-Initiated Reaction with N-Methylolacrylamide Followed by Crosslinking Reactions1

A wrinkle-resistant cotton fabric was produced by photo-initiated, free-radical reaction with N- methylolacrylamide monomer from aqueous solution to form a poly(N-methylolacrylamide) copolymer, followed by crosslinking reactions of the methylol groups of the copolymer with cellulose. The product had increased conditioned and wet wrinkle-recovery angles and retained breaking and tearing strengths and stiffness values in the ranges normally obtained for wrinkle-resistant cottons. The efficiency of the conversion of monomer to polymer was greater when the cotton-monomer solution was irradiated wet than when it was irradiated dry, and greater when irradiated with 254- and 300-nm ultraviolet light than when irradiated with 350-nm light. Catalysts used to initiate reaction of methylol groups were about equally effective whether they were included in the initial monomer solution or added to modi fied cotton fabric after copolymer formation.

Urea-Phosphoric Acid Hydrolysis of Mercerized Cotton Modified with Methylated Methylolmelamine

Mercerized cotton finished with a methylated methylolmelamine (MeMM) responded differently to hydiolysis with urea-phosphoric acid (UPac) than did similarly finished native cotton. UPac hydrolysis did not affect dry and wet wrinkle recoveries of mercerized cotton, but caused reduction in dry recovery angles of the unmodified native cotton control. Treatment with MeMM produced specimens with equally high dry and wet wrinkle-recovery angles regardless of nature of the control fabric; behavior of MeMM-treated fabrics, when subjected to UPac hydrolysis, was influenced by nature of the control fabric. With MeMM-treated mercerized fabrics, each subsequent hydrolysis removed about one-half of the bound nitrogen and virtually all formaldehyde; it destroyed dry recoveries, but had little effect upon wet wrinkle-recovery angles. Each MeMM retreatment completely restored these properties in products from mercerized cotton, but resulted in only partial restoration of recoveries in products from native cotton. X-ray diffractions after MeMM-UPac treatments of mercerized cottons indicated retention of the mixed cellulose I and II lattice of the unmodified control while products from native cotton retained the cellulose I lattice. Infrared spectra indicated that reaction, with MeMM in both cases, proceeded with loss of adsorbed water and occurred preferentially at the primary hydroxyl of cellulose. Unlike products from native cotton, modified mercerized fabrics did not show a buildup of polymer on the periphery of fiber cross sections after an increasing number of MeMM-UPac treatments. Hence, homopolymerization was not indicated in the MeMM treatment of mercerized fabrics.

Introduction and Removal of Durable Creases in Wrinkle-Resistant Cotton Fabric

Internally catalyzed, cross-linked cotton fabrics have provided the basis for an exploratory study of the introduction and removal of creases by thermal treatment. Durable creases having ratings of 4.0-5.0 have been developed in these cross-linked compositions which are characterized by conditioned and wet wrinkle recovery angles (W + F) as high as 300°. Creases are introduced by extended heat treatment or by multiple ironings of the wet fabric. By similar treatments of the creased fabric in the flat state, creases may be reduced substantially and, in some-cases, they may be reduced to the same extent as in unmodified cotton fabric. The study is based on cotton fabrics cross-linked with divinyl sulfone; the internal catalysis is provided by quaternary ammonium substituents introduced into the cellulose via ether linkages.

Behavior of Spun Rayon Fabric Treated by the Poly-Set Process

Behavior of spun rayon fabric treated by the poly-set process was investigated in comparison with cotton and polynosic fabrics reported earlier. There was no significant difference between the process steps as regards dry wrinkle recovery of spun rayon fabric. Unlike cotton and polynosic fabrics, the wet wrinkle recovery showed a high, significant difference between process steps, as observed for cotton and plynosic fabrics, although the difference was not big enough to classify them into two distinctly separate groups. The dominant influence of the water-sensitive links was observed for the dry state of spun rayon. Treatment based on the simple assumption that the difference in the dry and wet wrinkle recovery angles is a criterion of water-sensitive links showed the same tendency as for polynosic fabrics. The relationships between the various physical properties and wrinkle recoveries were investigated.

BEHAVIOR OF CELLULOSIC FABRICS TREATED BY THE POLY-SET PROCESS

Cellulosic fabrics (cotton, polynosic and spun rayon) were treated by the Poly-Set, two-step resin finishing process, using MMM, DMEU or their mixtures as finishing components and zinc acetate and zinc nitrate as polymerization (first step) and cross-linking (second step) catalysts, respectively.The effect of each process on the dry and wet wrinkle recovery angles was investigated.The alkali swelling of spun rayon was decreased most significantly by the resin finishing. DMEU was more effective than MMM to decrease the alkali swelling of the fabrics by the treatments.The relationship of the amount of crystal regions and the dimension of crystallite to the restrictional tendency on alkali swelling behaviors is discussed.

ON THE REACTION OF COTTON FABRICS WITH EPOXY COMPOUND IN THE PRESENCE OF ACIDIC CATALYSTS

Cotton fabrics were treated with diglycidyl ether (Epoxide I), glycerin diglycidyl ether (Epoxide III), butanediol diglycidyl ether (Epoxide IV), vinylcyclohexene dioxide (Epoxide VII) at low temperatures in the presence of various acidic catalysts and the effects of reaction variables on the degree of reaction and the wrinkle recovery angles were investigated in detail.When the treatment with various Epoxides was carried out at 40°C in the presence of different amount of magnesium fluoroborate for 4min., the dry and wet wrinkle recovery angles increased with increasing concentration of the catalyst and the degree of reaction, and reached the maximum values (dry, 190; wet, 245_??_275°) at the degree of reaction of 40%, and decreased at higher degrees of reaction. The maximum recovery angles (dry, 215_??_260°; wet, 265_??_290°) were obtained at the degree of reaction of 60_??_80% when the treatment was carried out at 60°C, and the maximum values (dry, 225_??_300°; wet, 295_??_300°) were obtained at the degree of reaction of 75_??_80% when the treatment was done at 80°C. Epoxide I gave higher dry wrinkle recovery angles than other Epoxides did. The treatment at lower temperatures improved the wet recovery much more than the dry recovery. The treatment at higher temperatures improved both dry and wet recoveries.Solubility and dyeability tests on the treated fabrics indicated the formation of effective crosslinks during the treatment.

Effect of Mercerizing- Strength NaOH on Fine Structures of Cottons Modified with Butadienediepoxide

Spectral and microscopical data revealed effects of 23% NaOH used either as a pretreating agent (catalyst) or as a mercerizing agent prior to or subsequent to treatment of cottons with CCl4 solutions of butadienediepoxide (BDO) in presence of more dilute NaOH catalysts. Whereas high dry and high wet wrinkle-recovery angles resulted when 2% or 15% NaOH catalyzed the BDO-cellulose reaction, only high wet recoveries were obtained with 23% NaOH catalysis. Conditioned recovery angles were higher, the weaker the base pretreatment. Postmercerization did not change recoveries of BDO- native cottons catalyzed by 15% NaOH but adversely affected dry angles of BDO-treated fabrics catalyzed with 2% NaOH and wet angles of those fabrics from reactions catalyzed by 23% NaOH. BDO-native cotton fabrics under 2% base catalysis retained the cellu lose I lattice; those under 15% NaOH catalysis exhibited mixed cellulose I- and II-type lattices, and those under 23% base catalysis consisted of mixed cellulose II- and III-type latices. Postmercerization resulted in (1) a cellulose IV-type lattice from BDO-treated fabrics which originally retained the native cellulose I structure, (2) a mixed cellulose II and IV-type lattice for those which originally possessed the mixed cellulose I- and II-type structure, and (3) no further effect upon those which originally possessed a mixed cellulose II and III-type structure. , Mercerized fabrics (mixed cellulose I and II) pretreated with aqueous NaOH and then reacted with BDO exhibited high dry and high wet wrinkle-recovery angles only when 2% NaOH catalyzed the reaction, and then only when add-ons of BDO were ex tremely high (35%). Otherwise, dry recovery remained essentially that of the mercerized control, and only high wet recoveries were obtained. Comparisons of fabric properties of BDO-mercerized cottons were made with those of the BDO-native cottons. Only with 23% NaOH pretreatment did comparable products from BDO-native cotton and BDO-mercerized cotton reactions have the same lattice type and show a tendency toward a cellulose III-type lattice. Microscopical and spectral data indicate the mixed I and II lattice was retained in all BDO-mercerized cottons pretreated with 2% NaOH and in all cottons pretreated with 15% NaOH or 23% NaOH and reacted to low add-ons of BDO. Postmercerization of these BDO-mercerized fabrics converted the cellulose I lattice to a II rather than to a IV-type lattice as occurred in BDO-native cottons. With those fabrics of high BDO add-ons postmercerization changed the cellu lose II-type lattice to a cellulose III lattice.