The Improvement Of The Opaque Performance Of High-Count Lightweight Pure Cotton Fabrics

The excellent breathability,moisture permeability,and soft feel of cotton fiber make its fabrics highly favored by consumers.Light-colored cotton fabrics provide cool and comfortable wearing experience,but their visual shielding or opaque performance is often inadequate,which becomes a significant contradiction.The lack of shielding in high-count yarn and thin cotton fabrics has further highlighted the need for enterprises to enhance the visual shielding performance of cotton fabrics.At the same time,the common way at that time to improve fabric shielding by mixing with impermeable chemical fibers was not applicable to cotton fabrics,and thus,more attention was paid by enterprises to the study of cotton fabrics to enhance visual shielding performance.Therefore,for the production of light-colored light cotton fabrics in summer,enhancing their visual shielding effect was one of the important elements.In addition,opaque cotton fabrics also had a wide range of application prospects,such as medical,beauty,home,and other occasions that needed to protect privacy.Therefore,the study of cotton fabric opaque had important practical value.The improvement of opaque performance of white high-count cotton fabrics using the padding process was focused on in this paper.The cotton fabric was padded with an opaque finishing agent containing TiO₂to study the effect of different process parameters on the performance of the finished fabric and to optimize the process parameters.The effect of opaque was characterized by testing the optical properties of the fabric,including whiteness,reflection,transmittance,shielding rate,and difference in grayness of the fabric,as well as the air permeability,moisture permeability,and washing resistance of the fabric before and after finishing.Finally,on the basis of the original opaque finishing agent,different particle sizes and TiO₂concentrations were added to try to further enhance the opaque effect.The main conclusions were obtained as follows:（1）The fabric opaque was optimized by setting the bath ratio to 1:30,the padding pressure to 0.10 MPa,and the padding method to two dipping and two rolling.The opaque fabric with a padding rate of 70%～90%could be obtained.SEM images were taken,and it was found that more TiO₂particles could be loaded on the cotton fiber.（2）Different concentrations of 40g/L,50g/L,and 70g/L opaque solutions were prepared to investigate the difference in TiO₂particle loading effect after the fabrics were finished with different concentrations of opaque solutions.After being finished by solutions of different concentrations the test results showed that the square meter weight and thickness of the fabric were improved.At the same time the SEM images showed the TiO₂particles were more uniformly distributed on the surface of the fabric after finishing with a low concentration of opaque solution,while the agglomeration phenomenon appeared on the surface of the fabric after finishing with a high concentration of opaque solution.（3）The finished fabric showed an increase in whiteness,reflectivity,and shielding rate,as well as a decrease in transmittance and grayness difference compared to the original fabric.Furthermore,an increasing trend was observed in the fabric whiteness and shielding rate with the increase of fabric weight gain rate,while a decreasing trend was observed in the fabric transmittance and grayness difference,under the same padding pressure.（4）The fabric taking performance was tested after being finished with different concentrations of opaque solution.The results showed that when the concentration of the finishing agent was too high,the fabric breathability and moisture permeability decreased significantly.When the concentration of the finishing agent was low,the fabric taking performance only decreased slightly.At the same time,the changes in fabric washing resistance after finishing with different concentrations of opaque solution were explored and improved.It was found that after 45 minutes of washing,the fabric’s opaque performance decreased.However,when the washing time exceeded 45 minutes,the optical property of the fabric changed moderately and stabilized,and the opaque performance did not undergo significant changes.（5）Different particle sizes and concentrations of TiO₂were added to a 40 g/L opaque solution to investigate the effect of enhancing opaque after fabric finishing.It was found that the opaque enhancement was not significant when TiO₂was added compared to the fabric obtained without TiO₂padding.Only when 90 nm rutile TiO₂was added at a lower concentration,the optical properties of the fabrics were slightly improved compared to those obtained without TiO₂.