|
Acrylate emulsion has been poured attention to lots of fields because of excellent film-forming property, strong adhesion,etc. However, some draws such as brittle under freezing and stick back under warming still exist in its application. As an example, hand feeling is stiff and wet rubbing fastness is poor in the application of printed fabric. Polysilicone is equipped with splendid flexibility, surface smoothness, excellent resistance to low temperature and high temperature, and so on. Therefore, in this paper, acrylate emulsions with a core-shell structure modified by home-made PVPS were prepared. Then, acrylate emulsions as printing binding agents were applied in pigment printing. There are three parts in this research.Part I:Preparation and properties of oligomer PVPS.Oligomer PVPS was prepared with an approach of cationic ring-opening emulsion polymerization. Taking into account these conditions as follows:organic acid catalyst, emulsifier, coupling agent KH-571, polymerization temperature, heat preservation time, and which were the influence of PVPS in polymerization stability and properties of emulsion. It was found that a optimal polymerization process was detennined as semi-continuous monomers addition, catalyst DBSA10.0wt%, emulsifier,3.0wt%, delay time2.0h and dosage of10.0wt%of coupling agent KH-571, m (Anion)/m(Non)=1:2, polymerization temperature around80℃, heat preservation time4～6h. As a result, it was capable of preparation of light blue semi-translucent emulsion with good stability and the conversion rate of89.4%. The characterization of Nano-ZS and FTIR presented that the average particle size of the emulsion was about50.0nm with narrow particle size distribution, and KH-571and ring-opening compound was covalent bond.Part II:Preparation and properties of acrylate emulsion modification of PVPS with a core-shell structure. In this part, acrylate latices with a core-shell structure modified by PVPS were prepared by acrylate monomers and home-made vinyl pre-polysiloxane, which was carried out by emulsion polymerization, with the particularly application of core-shell particle design method. As is indicated from experimental results, optimum polymerization condition was determined as follows: process method of preliminary emulsion—half continuous—seed emulsion, compound emulsifier m (Anion)/m (Non)=1:2, HLB=14～15, and dosage of4.5～5.0wt%, redox system initiator m (APS):m (NaHSO3)=2:1,0.5wt%, reaction temperature and stirring speed according to gradient change, holding time1.5～2h, pH buffer NaHCO30.5～0.6wt%, cross-linking monomer EGDMA2.3wt%, oligomer PVPS10.0～15.0wt%, and it was possessed of good stability and gel fraction less than5.0wt%.The latex were characterized by FTIR, TEM, DSC, Nano-ZS, AFM. The characterization results demonstrated that acrylate monomers and home-made PVPS were inhabited by chemical covalent bond, emulsions were possessed of core-shell structure with glass transition temperature-23.1℃/10.4℃, and the average particle size of emulsion was around114.5nm with narrow particle size distribution. In addition, emulsion films were measured both in thermostability and tensile strength by means of TGA and universal material testing machine.Part III:Application of home-made PVPS modified acrylate emulsion as adhesive in pigment printing.In this part, it was researched for the influence of printing paste and printing process in fabric printing performance. The results held view that an appropriate printing paste recipe was adhesive20.0wt%, thickner of poly acrylate acid3.0wt%when paint blue was5.0wt%, etc, and the optimum printing process was from printing to pre baking80℃×3min and then curing130℃×3min. In order to obtain better color fastness, this part also studied that it included the effect of printing properties of cotton fabric contributed to cationic modifier treatment in performance of printing fabric and then compared home-made samples with other printing adhesive. The results showed that printed fabric, which was treated by home-made acrylate adhesive with a core-shell structure, was with the rubbing fastness to dry and wet being4-5and3, soft hand feeling, non-stick back and excellent surface smoothness. They were endowed with good market application prospects.
|