Development And Application Of High Physical Properties Waterborne Polyurethane Clothing Leather Foam Layer

As a kind of industrial products that people cannot do without daily wear,home and travel,synthetic leather is widely used in clothing,bags,car interiors,sofas and other products.In recent years,with the improvement of the concept of green development at home and abroad,the process of"oil-to-water"in the synthetic leather industry is being promoted,and the green emission reduction of the synthetic leather industry mainly includes two reliable methods:solvent-free preparation and water-based dry preparation.The research of water polyurethane,as the technical key of waterborne dry synthetic leather,has become a research hotspot in the industry.This project takes the general trend of"oil to water"in the synthetic leather industry as the development background,with the purpose of developing water polyurethane emulsion for the foam layer of clothing synthetic leather with high physical properties and high performance ratio,combined with the physical property requirements of the clothing synthetic leather industry,and starting from the synthetic raw materials and process conditions of water polyurethane,the following work is mainly carried out:Firstly,an aliphatic water polyurethane emulsion for the foam layer of clothing synthetic leather with yellowing resistance,excellent peeling mechanical properties and excellent hand feel（drape）was prepared.The prepolymerization stage raw materials were studied hexamethylene diisocyanate（HDI）,isophorone diisocyanate（IPDI）,dicyclohexylmethane diisocyanate MDI(H₁₂MDI),polypropylene glycol（PPG）.Effect of polycarbonate glycol（PCDL）and polytetrahydrofuranediol（PTMEG/PTMG）three polyols and molar ratio of the two on water polyurethane emulsion and finished clothing leather;The effects of carboxylic acid hydrophilic chain extender and sulfonic acid hydrophilic chain extender on emulsion and finished garment leather were compared.The four diol extenders of neopentylene glycol（NPG）,1,4-butanediol（BDO）,diethylene glycol（DEG）and 1,4-cyclohexanedimethanol（CHDM）were investigated accordingly,the three diamine extenders of ethylenediamine（EDA）,isophorone diamine diamine（IPDA）and hydrazine hydrate were investigated accordingly,and the dosage of trimethylolpropane（TMP）and F3056D internal crosslinkers was investigated accordingly.Aliphatic water polyurethane emulsion with peeling strength of0.59N/cm,sag grade 5 and fold recovery grade 5 was prepared.Secondly,according to the market demand for cost-effective water dry garment leather,a cost-effective aromatic water polyurethane emulsion for the foam layer of garment synthetic leather was prepared.The differences between aromatic isocyanate MDI and aliphatic isocyanate IPDI+HDI in emulsion and garment leather foam layer were compared,and the defects of MDI water polyurethane compared with aliphatic isocyanate IPDI+HDI were clarified.By introducing an endcaping agent and increasing the degree of cross-linking,the surface tension of the emulsion and the mechanical properties of the finished leather are optimized.The orthogonal test of three factors and four levels was designed,and it was concluded that the emulsion had the best comprehensive performance when the amount of 15%capping,the amount of TMP added was 0.35wt%,and the addition amount of F3056D was17.5wt%.