Reoptimization Of Synthesis Conditions Of Polycarboxylic Acid Formaldehyde-free Durable Press Finishing Agent LMP And Its Application

Although polycarboxylic acid formaldehyde-free durable press finishing agent LMP synthesised previously in the laboratory had good application effect on several representative cotton fabrics with different structure and specifications.DP rating of LMP finished fabrics in the pilot-scale was less than that of the finished fabrics in the laboratory(less than 3.0)and a small amount of precipitation appeared in LMP after placing more than one month.Therefore,this study focused on reoptimizing the synthesis conditions and pilot-scale application of LMP synthesized with commercial chemicals after obtaining satisfactory results in laboratory,aiming at promoting the industrial application of polycarboxylic acid formaldehyde-free durable press finishing agent LMP.The adding method of initiator,monomer molar ratio and reaction temperature were reoptimized by evaluating the main properties,including wrinkle recovery angle(WRA),tear strength(TS)and whiteness(WI)of the LMP finished cotton fabrics.The resulted synthesis conditions were as follows:the initiator divided into eight sections with ten minutes interval to add into reaction system,12:1 for the monomer ratio of maleic acid and itaconic acid and 100?for the reaction temperature.After reoptimizating reaction conditions,the monomer conversion rate increased from 66.7%in the past experiment to more than 90%and the application effect of LMP was better.WRA and DP rating of finished Oxford cotton fabric was respectively 271°and3.6.Good durable press performance was obtained when LMP was applied on seven kinds of cotton fabrics with different colors,structure and specifications,which indicated LMP has a certain universality.Comparing with the other polycarboxylic acid formaldehyde-free durable press finishing agents,the durable press performance of LMP treated cotton fabric was obviously better than those finished with polymaleic acid?polyfumaric acid?polyitaconic acid?polyaconitic acid and polyacrylic acid,very similar to BTCA treated fabrics.The durable press performance of LMP synthesized with commercial chemicals was the same as that with reagent grade chemicals in the laboratory.The two different specifications were finished with LMP(synthesized with commercial chemicals)in pilot-scale by equipment of factory.The treated fabrics were tested by Intertek and the results were that the DP rating?3.5 and the smoothness appearance of seams rating?4.0 after five home laundering cycles.The whiteness of the white fabric was decreased from 81 of untreated fabric to 79.The other main performances and properties of treated fabrics meet the requirements of No-iron textiles standard.The study on the relation between esterlinkage concentration and WRA of LMP finished cotton fabric showed that an excellent linear relationship was found between them with correlation coefficient R~2about 0.93.Therefore,WRA could be used to accurately characterize the degree of cross-linking of LMP and the fiber macromolecule.The molecular weight and its distribution coefficient of LMP synthesized under different conditions were determined by GPC with an aqueous phase.The data showed that the molecular weight were significantly increased when the amount of itaconic acid was more than that of maleic acid in reaction system,which could be due to that itaconic acid was easier proceed free radical polymerization than maleic acid with symmetric structure,causing the increase of the molecular weight of LMP.The esterlinkage concentration or WRA of the finished fabrics by LMP with the larger molecular weight was lower,but higher with the wider distribution coefficient,indicating that lower molecular weight and broader distribution of LMP molecular weight were beneficial for improving durable press performance.The concentration of phosphorus and the amount of unsaturated monomer on the finished fabric were respectively determined with inductively coupled plasma atomic emission spectrometry and high performance liquid chromatography.The data showed that phosphorus concentration on finished fabric increased with the increase of the total amount of monomer,the WRA of finished fabric increased with the increase of phosphorus content,which was mainly due to that the H-P-H of sodium hypophosphite as the catalyst could react with the C=C double bond in the unsaturated monomer,resulting in cross-linking of the fiber macromolecules.