Preparation and performance of copper modified antimicrobial and anti-mite polyamide 6 fiber
Objective The application of copper antimicrobial agent in fiber materials is faced with three major problems.Firstly,the functional nano powder has serious agglomeration and poor compatibility with polymer materials,which makes it difficult to disperse evenly.Secondly,copper is easy to be oxidized and discolored,resulting in poor stability and uniformity of fiber color.Thirdly,spinnability and mechanical properties of fiber decrease with the increase of antimicrobial agent content,therefore it is difficult to increase the content of copper antimicrobial agent in the fiber.It is important to improve the dispersion,interfacial compatibility,and antioxidant properties of copper antimicrobial agent in fibers.Method In this study,the nano spherical copper antimicrobial agent was coated with oleic acid.Two types of copper modified PA6 antimicrobial masterbatch containing 1.1%and 2.1%copper antimicrobial agent were obtained by squeezing granulation.Copper modified PA6 antimicrobial and anti-mite fibers were obtained by melt spinning and composite spinning,respectively.The structure,morphology and interfacial compatibility of copper antimicrobial agent,thermal stability and spinnability of antimicrobial masterbatch,copper content,mechanical properties,antimicrobial,and anti-mite properties of fiber and fabric samples were analyzed.Results The diffraction peaks were found sharp with no other impurity peaks appearing,indicating that the sample was well crystallized and was still pure after modification.No obvious weight loss is found during the dehydration at about 100℃,which indicated satisfactory hydrophobicity of the sample.Sample C1 showed about 0.4%of weight loss at 300℃,and its thermal stability met the requirement of melt spinning,and the dispersion was good without large-size agglomeration under the electron microscope and showed good hydrophobicity with water contact angle of 146°,which was consistent with the TG results.Whether it is melted spinning or composite spinning,pre-oriented yarn sample had high fiber yield of 94%.The fiber yield of draw textured yarn sample is 93%and 94%,respectively.The modified spherical copper antimicrobial agent hardly affected the mechanical properties of PA6,which could be attributed to the reduced agglomeration and improved dispersion of the oleic acid modified spherical copper antimicrobial agent,resulting in fewer large rigid particles in the fiber.The interfacial interaction between PA6 and copper particles was enhanced with the help of oleic acid.The elongation at break of the copper modified PA6 fiber was 29.95%and the tensile breaking strength was 4.43 cN/dtex.For Candida albicans,Staphylococcus aureus and Escherichia coli,copper modified PA6 DTY sample(X1′)and copper modified PA6 sheath-core DTY sample(X2′)both have high bacteriostasis rate of 99%.The bacteriostasis rate was still over 99%after washing for 50 cycles,indicating that the samples had good resistance to washing and superior long-lasting antibacterial performance.After washing,the copper content of the X1′ sample was 1.26%and that of the X2′sample was 1.11%.Compared with the copper content of the two fiber samples before washing,the copper content remained basically the same within the allowable testing error.For mixed test,fungi colony consists of Aspergillus niger,Trichoderma viride,Penicillium funiculosum and Chaetomium globosum,the mildew proof grade of the fiber reached grade 0,meaning no obvious mildew colony under magnifier.X2′ samples were woven into fabric for the anti-mite performance test.The result showed that the average number of mites in the test group was 22 and that in control group was 194,suggesting the repellent rate of mites of 89%.Conclusion The dispersibility of oleic acid coated spherical copper antimicrobial agent and its compatibility with PA6 are good.Copper modified PA6 antimicrobial masterbatch has good thermal stability and spinnability.Copper modified PA6 antimicrobial and anti-mite fiber has high fiber yield of 88%and excellent color consistency at a high antimicrobial addition of 1.1%.The mechanical property of the fiber is adjustable.The antimicrobial,mildewproof and anti-mite properties of fiber samples are strong and durable.Therefore,copper modified PA6 antimicrobial and anti-mite fibers have broad industrial application potentiality in military personal protective equipment,fiber products for medical and health industry and textiles for civil clothing and home decoration.