Modification Of Acrylic-based Resin And Research On Printing Process

Bisphenol A epoxy acrylic resin is widely used in coatings and ink industries due to its high light activity,fast curing rate,good mechanical properties,and low price.It has also been widely studied in the field of mold light curing.Due to the LCD type 3D printing light curing started late,and the corresponding acrylic-based resin has been studied less,and has the inherent defects of low double bond conversion at the gel point,and the hardness does not meet the requirements of high standards in the industry.It is necessary to modify the resin and adjust the printing parameters.The ultra-fine powder ZrO₂ was surface-treated with an acidified coupling agent A151,and after grafting an organic chain containing a double bond,it was used as a reinforcing phase modified bisphenol A epoxy acrylic resin.Using tensile strength as an index,the optimal process conditions determined by orthogonal experiments are m?prepolymer?: m?monomer?= 1:1,the mass fraction of photo initiator 819 is 1.5%,the mass fraction of the enhanced phase ZrO₂ is 1.5%,and the curing time of the single layer is 10 s.Compared with the blank resin,the optimized resin scheme resulted in an average tensile strength improvement of 60.58%,a shrinkage reduction of 71.3%,and a bending strength improvement of 31.2%.Different concentrations of acrylic monomers were added to bisphenol A epoxy acrylic resin to prepare 3D printed light curable resin materials.The results show that with the addition of 5% acrylic monomer,the double bond conversion of the resin increased by 58.5%,the tensile strength reached 52.64 MPa,the flexural strength was 168.88 MPa,and the flexural modulus was 4449.53 MPa,which were 159.3%%,49.9%,56.8% higher than the blank resin;the rough tensile section reflects the increase in fracture toughness of the resin.Resin shrinkage is 6.56% when acrylic acid is added at 5%,and the curl coefficient obtained from printing of double cantilever parts is 7.16%,which reflects the good printing accuracy of the resin.In order to provide a theoretical basis for the photo-curing process,an acrylic-based photosensitive resin containing polyethylene glycol 200 was prepared,and the effects of the thickness of the slice layer,the curing time of the single layer,the printing construction direction,and the post curing treatment time on the curing process were studied.The results show that the time required for the four layer thicknesses to reach their highest conversion rates is the same,and delayed gelation occurs;the same layer thickness,the longer the single layer curing time,the higher the double bond conversion rate,but the single layer curing time more than 25 s,the generated unstable new bonds will be broken and the double bond conversion rate will be reduced.Increasing the layer curing time to 25 s can greatly improve the adhesion between vertical printing layers,and the strength is close to horizontal printing.At the same time,the post-curing time of 20 minutes can exert the greatest positive impact,especially for short time fast printing.