Synthesis And Characterization Of Self-matting Waterborne Polyurethanes Resin

In recent years,with the changes in people's aesthetic concepts,the use of matting materials has become more and more extensive,and all aspects of daily life,such as paper,clothes,etc.,are derived from their excellent appearance characteristics and touch.There are many methods for material matting,and the use of matting agents is the most widely used,but this method has inherent defects,such as difficult storage and poor mechanical strength.Self-dulling PUD(polyurethane dispersion)is a binary colloidal system with low gloss and atomization on the surface after drying and unstable film formation without adding any matting agent,using water as the dispersion medium.Compared with physical matting polyurethane,It has the advantages of environmental protection,high performance and stability.The body matting water-based polyurethane(WPU)will not cause damage to the environment in experiments and daily use,and it can effectively improve the defects of matting agent addition.In recent years,with the strengthening of people's environmental awareness and the introduction of national environmental protection policies,self-matting waterborne polyurethanes will replace physical matting polyurethanes.A trend.This thesis first chooses toluene diisocyanate(TDI)as the hard segment,polytetrahydrofuran glycol(PTMG,with molecular weights of 2000 and 1000)as the soft segment,dimethylolpropionic acid(DMPA)and 2-[(2)with different molecular weights.-Aminoethyl sodium ethanesulfonate(A95)is a compound hydrophilic chain extender,and ethylenediamine(EDA)is a non-hydrophilic chain extender to prepare a series of self-dulling PUDs.The synthetic self-matting PUD microsphere technology adopts the carboxysulfonic acid group method to prepare a series of WPU emulsions by controlling the hydrophilic group content,chain extension degree,molecular weight and distribution during polymerization and other parameters to control the particle size and distribution of the emulsion.,The synthetic solid content is 40% self-dulling PUD resin.Then select isophorone diisocyanate(IPDI)as the hard segment,polytetrahydrofuran ether glycol(PTMG-1000)as the soft segment,1,4-butanediol(BDO)as the non-hydrophilic chain extender,2,2-Dimethylolpropionic acid(DMPA)is a hydrophilic chain extender,triethylamine(TEA)is a neutralizer to synthesize prepolymers,and ethylenediamine(EDA)is a post-chain extender,which is controlled by the hydrophilic group A series of large particle size waterborne polyurethane emulsions were prepared.ATR-FTIR is used to characterize the chemical structure of self-extinction PUD.Nanoparticle size analyzer and 3D-AFM are used to observe particle size distribution and surface roughness,and scanning electron microscope(SEM)and transmission electron microscope(TEM)are used to observe the emulsion surface of PUD.And the particle morphology,the gloss,light transmittance,stability,contact angle and mechanical properties of PUD were tested,and the extinction mechanism of this new type of PUD without adding any additional matting agent was explained in detail.Studies have shown that although the self-dulling PUD made with TDI as the hard segment is difficult to control due to its structural limitations during the synthesis process,the surface microscopic rough emulsion particles assembled by drying and instability are solid spherical,rod-like or even collapsed.,The particle size range of the milk particles is between 400-800 nm,and the corresponding self-dulling PUD coating film has a light transmittance of about 20%,which has a strong covering ability.The 60° minimum gloss of the PUD film can reach 0.8,which can reach expectations.Effect: The self-dulling PUD made with IPDI as the hard segment not only obtains excellent mechanical properties by controlling the size of the particle size,but also achieves the expected matting target.