Preparation Of Modified Water-based Polyurethane And Its Application In Water-based Ink

Today in the 21 st century,laws and regulations are gradually improved,environmental protection concepts are deeply rooted in the hearts of the people,the traditional extensive model is quietly withdrawing from the stage of history,the era requires the development of green chemistry,the past high-pollution and high-emission industries need to be upgraded and updated.Waterborne polyurethane products have extremely low content of organic solvents,less volatile pollution,and are very environmentally friendly.They have gradually replaced the position of solvent-based polyurethanes and are widely used,especially in water-based polyurethane inks.However,water-based polyurethane ink also has its own shortcomings,such as poor adhesion to low-polarity substrates and slow drying speed.Therefore,it is necessary to modify and explore water-based polyurethane ink binders to broaden its scope of use.This article mainly studies the modification of chain extenders with long aliphatic side chains to reduce the polarity of the binder,increase the wetting ability on low-polar substrates,and use sulfonate/carboxylate compound hydrophilic chain extension It is used to increase the solid content of the binder and optimize the storage and transportation cost of the product.This article mainly includes the following contents:(1)Based on isophorone diisocyanate(IPDI),polyneopentyl adipate diol(PNA)/ poly 1,4-butanediol adipate diol(PBA),dihydroxy Methyl propionic acid(DMPA),1,4-butanediol(BDO)and hydroxyl-terminated polydimethylsiloxane(PDMS)are the main raw materials,containing long fatty side chain glyceryl monostearate(MG)As a chain extender modification,explore the influence of different contents of MG on various properties of the binder.After infrared spectroscopy,composite film X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD),water resistance,stress strain test,emulsion performance test,T peel strength and other tests,it is concluded that with the MG in the system.With the increase of the content,the water resistance of the sample gradually increases.When the MG content is 8%,the water absorption rate of the film is only 0.63%;the surface tension and contact angle of the emulsion show a decreasing trend,but when the MG content in the system is 10% At that time,there was a slight rise.The tensile strength showed a downward trend with the increase of MG content in the system.The peel strength increases with the increase of MG.When the MG content is 8%,the maximum is 9.6N/25 mm.If this amount is exceeded,the peel strength decreases.Comprehensive indicators,and considering the storage stability period of the emulsion,select WPU6(stability> 6 months,viscosity 12 s,surface tension 43.19 m N/m,water absorption 1.54%,solid content 22%,peel strength 9N/25mm)As an ink binder sample to configure the ink in the next experiment.(2)Using IPDI,PBA/PNA,BDO and hydroxy-terminated polydimethylsiloxane(PDMS)as the main raw materials,sulfonate hydrophilic chain extender A95 and carboxylate hydrophilic chain extender DMPA are used in combination,Used to synthesize the target high solid content water-based polyurethane ink binder.Explore the effects of different DMPA/A95 addition ratios on the performance of ink binders.After a series of tests,it is concluded that with the increase of DMPA content,the crystallization peak of the film is enhanced;the water resistance of the film is better;the surface tension of the emulsion shows a decreasing trend,and the surface tension of the WPU4:1 sample is the lowest 32.65 m N/m;stretched The strength first increases and then decreases.The elongation at break generally increases first and then decreases.When DMPA/A95=2:3,the maximum tensile strength is 30.42 MPa,and the maximum elongation at break is 860%..The change of DA/A95 ratio has little effect on the change of peel strength.The peel strength of all five groups of ink binders meets the performance requirements.Based on the above data and conclusions,select WPU 4:1(stability> 6 months,viscosity 12 s,Surface tension 32.65N/m,water absorption rate 14.66%,solid content 31%,peel strength12.88N/25mm)The sample is an ink binder for subsequent ink configuration experiments.(3)Using citric acid and urea as the carbon source and nitrogen source respectively,using the microwave method to synthesize fluorescent carbon dot CDs in one step,acting as the fluorescent agent in the fluorescent ink,using the polyurethane emulsion WPU6 and WPU4:1prepared by the first two as the ink The binder is configured with Ink 1 and Ink 2 respectively.The various performance indicators of the ink were tested.The test results showed that the two groups of inks have better adhesion fastness on the PET substrate and can be used for surface printing of PET films.However,ink 2 is not suitable for long-term humid environment due to the limitation of the water resistance of the binder.Green fluorescence is emitted under the irradiation of 365 nm ultraviolet lamp.