| Superfine fiber synthetic leather（referred to microfiber leather）is made of sea-island microfiber nonwoven fabric with three-dimensional network structure as the base fabric,then impregnated with resin,followed by the fiber opening and refinement,sanding and other process.As a synthetic material,it has great application prospect in automobile interior decoration,luggage leather shoes,outdoor materials and other fields,because it owns the characteristics of microfiber with good fluffiness,good softness,and excellent hygroscopicity,as well as excellent moisture permeability,air permeability,waterproof and mildew resistance brought by the random three-dimensional bundle structure distribution of natural leather.According to the application requirements of different fields,such as superhydrophobic,thermal energy storage,antibacterial,anti-ultraviolet,and so on,it is necessary to carry out functional finishing of microfiber leather.Compounding nano-fillers in microfiber leather is an efficient way to realize the functionalization of microfiber leather.Among them,microencapsulated fillers can encapsulate and protect active liquid/solid substances（such as essential oil,phase change materials,dyes,flame retardants）which are difficult to directly finish on the fabric surface and finish to the fabric surface.At the same time,it has adjustable size,shape and chemical surface to adapt to the microfiber leather substrate,which has great application potential in the functional finishing of microfiber leather.However,at present,there are two problems in the finishing of microfiber leather based on microcapsule fillers:（1）most of the preparation methods of multifunctional microcapsules are complicated and time-consuming,and it is difficult to apply on a large scale.（2）the use of alkali treatment or organic solvent in the fiber opening process of microfiber leather would change the surface tension of the fiber surface and etch the functional finishing agent,which will lead to the sharp decline of the function of the microfiber leather.Therefore,there is an urgent need to develop the microcapsules preparation and finishing technology of functional microfiber leather with spontaneous repair or alkali resistance.In order to solve the above problems,two kinds of functional microcapsules were designed and prepared by using the newly developed Pickering emulsion technology,which used solid particles instead of traditional emulsifiers:（1）the photo-controlled releasemicrocapsuleswithlowsurfaceenergyliquid triethoxy-1H,1H,2H,2H-tridecyl-n-octyl silane（FAS13）as the core material and titanium dioxide（Ti O2）and silicon dioxide（Si O2）as the surface.（2）the alkali-resistant thermal energy storage microcapsule with phase change paraffin wax(C22)as core material,and titanium carbide（Ti C）and silicon dioxide as the surface.Then,the prepared microcapsules were mixed with silicone resin and compounded with microfiber leather substrate to prepare functional microfiber leather.The super-hydrophobic self-repairing and alkali-resistant fiber opening thermal energy storage function of microfiber leather are endowed.The main research contents and results are as follows:（1）Super-hydrophobic self-repairing microfiber leather based on photo-controlled release（FAS13@PS）-Si O2/Ti O2microcapsules.Using styrene（St）and fluorosilane FAS13 as oil phases,nano-Si O2and nano-Ti O2as solid particle emulsifiers,the Pickering emulsion was constructed with the auxiliary emulsification of silane coupling agent 3-（methacryloyloxy）propyl trimethoxysilane（MPS）,and the photo-controlled release（FAS13@PS）-Si O2/Ti O2microcapsules were obtained after polymerization.The morphology and composition of microcapsules were characterized,and the effects of silane coupling agent dosage,FAS13 dosage,the ratio between nano-Si O2and nano-Ti O2and the overall dosage on the particle size and composition of microcapsules and their regulation laws were investigated,and the release of microcapsules under ultraviolet irradiation was studied.The prepared microcapsules were mixed with silicone resin（PDMS）and coated on the surface of the base fabric to obtain the original leather.The influence of the solid content of microcapsules on the hydrophobicity of the original leather was explored.Ultrafine fiber leather was obtained after hot alkali fiber opening,and its superhydrophobic self-repairing renaturation under ultraviolet irradiation was studied.The antifouling,self-cleaning and friction resistance of self-repaired super-hydrophobic microfiber leather were investigated.The results show that the microcapsules are strawberry-shaped,with Si O2and Ti O2on the surface and fluorosilane FAS13 coated inside.Regulating different variables can effectively regulate the particle size and composition of microcapsules.Under ultraviolet irradiation,photocatalytic Ti O2will catalyze the degradation of microcapsule shell,which will rupture and release fluorosilane.When the solid content of microcapsules reaches 30 wt%,the super-hydrophobic leather can be obtained,and its water contact angle can reach 153.2°,and the hydrophobicity decreases to 118.3°after fiber opening,and it has super-hydrophobic self-repairing renaturation after ultraviolet irradiation.The original leather and self-repairing microfiber leather have antifouling property to rhodamine B dye solution and self-cleaning property to dust.And after 200 times of rubbing,it can still maintain super hydrophobicity.（2）Thermal storage microfiber leather based on alkali-resistant(C22@PS)-Si O2/TIC microcapsules.With St and C22as oil phases,nano-Si O2and nano-Ti C as solid particle emulsifiers,the Pickering emulsion was constructed by the auxiliary emulsification of silicon MPS,and(C22@PS)-Si O2/TIC microcapsules were prepared after polymerization.The morphology and composition of microcapsules were characterized,the effects of the ratio of Si O2to Ti C and the amount of paraffin on the particle size and thermal energy storage performance of microcapsules were investigated,and the morphological changes and stability of microcapsules under alkali boiling were studied.The prepared microcapsules were mixed with PDMS and coated on the surface of base fabric to obtain thermal energy storage leather;The hydrophobic property,antifouling property and friction resistance of thermal energy storage raw leather was investigated.Microfiber leather was prepared by hot alkali defibering,and the thermal energy storage performance and its changes before and after defibering were studied.The results show that the microcapsules are strawberry,with Si O2and Ti C on the surface,which has a good encapsulation effect on paraffin.The particle size,composition and heat transfer rate of microcapsules can be effectively controlled by adjusting the ratio of Si O2to Ti C and the amount of paraffin,and Ti C particles can effectively inhibit the supercooling of paraffin.The microcapsules have no obvious change after alkali boiling,and have good alkali resistance.The prepared thermal energy storage leather has good heat storage performance,good hydrophobicity,antifouling performance and friction resistance.After alkali fiber opening,its thermal energy storage performance is well maintained.The heating rate of raw leather and microfiber leather increases with the increase of Ti C particle content,and the thermal insulation performance of microfiber leather increases with the increase of paraffin content.In short,light-controlled release（FAS13@PS）-Si O2/Ti O2microcapsules and alkali-resistant(C22@PS)-Si O2/Ti C microcapsules were prepared by Pickering emulsion method with the auxiliary emulsification of silane coupling agent,and combined with silicone resin to prepare super-hydrophobic self-repairing microfiber leather and alkali-resistant microfiber leather with thermal energy storage.The prepared microfiber leather successfully reduced the functionality of the fiber opening process.This paper not only provides a new research method for preparing double-particle microcapsules with Pickering emulsion,but also broadens a new theoretical basis for realizing the functionalization of microfiber leather. |
