Study On The Preparation Of Polymer Microneedles By The Method Of Hot Embossing In Solid-like State

Polycarbonate microneedles were prepared by the method of hot embossing in solid-like state.Through the finite element software,the molding process of microneedles and the influence of the process conditions(embossing temperature,pressure and embossing time)on the microneedles molding are simulated.On the basis of the results obtained from the experiment of the microneedles mold with no limit function,the heating system and the microneedles mold with no limit function are improved.The effect of processing parameters on the forming rule of microneedles in the process of preparing polycarbonate microneedles by the method of solid-like state hot embossing is studied by the microneedles mold with no limit function.In addition,the influence of processing parameters on the forming rule of microneedles in the process of preparing polycarbonate microneedles by the method of special solid-like state hot embossing is studied.The results are as follows:The effects of processing conditions on micro needle forming under non domain and limited conditions were simulated by finite element method.The regulars are the same.The laws are the same.The increase of temperature will improve the flowability of the materials and help to form the microneedles.The increase of pressure promotes the formation of microneedles.When the temperature is low,the increase of pressure can increase the length of microneedles.When the temperature is higher,the increase of pressure can accelerate the speed of micro needle forming.Reasonable selection of stamping time can improve the preparation efficiency of microneedles.Under no limited conditions,when the pressure is 50MPa and the temperature is 156?,the microneedles forming is good.Under limited conditions,when the pressure is 12MPa and the temperature is above 149?,the microneedles forming is good.It is proved that the limited conditions are helpful to the forming of microneedles.Because the heating system of the equipment is unreasonable,the process is unstable.The rapid heating and temperature control of the equipment is realized by the method of "six surface heating",and the manufacturing efficiency of the microneedles is greatly improved by improving the heating system with the no limited mold.In the process of the preparation of polycarbonate microneedles by the no limited microneedles mold after the improved heating system,it is found that the increase of temperature and pressure contributes to the molding of the microneedle.By adding the limited domain function to the mold,the polycarbonate microneedles with uniform length was successfully prepared by the method of hot embossing in solid-like state.The required pressure is only 24%before the improvement.Polycarbonate microneedles were prepared by the method of hot embossing in solid-like state using the microneedles mold with limited domain function.The results of the equal and differential temperature of the upper and lower mold show that the increase of temperature and pressure can promote the molding of the microneedles under the condition of the equal temperature of the upper and lower mold.The embossing time is only 35?40s and the cooling time is only 5min when the pressure is 12MPa and the temperature is 151?.In the process of preparing polycarbonate microneedles by the method of special hot embossing in solid-like state,if the temperature(80?90?)of the upper mold plate can be reasonably selected,the embossing time and cooling time can be reduced on the premise of guaranteeing the quality of the microneedles.The temperature of the lower mold plate plays a decisive role in the microneedles forming.Good polycarbonate microneedles can be prepared when the temperature of the lower template is greater than 154?.The relationship between pressure and microneedles forming quality is positively correlated in a certain range.With the increase of stamping time,the average length of the microneedles is lengthened.If we can control the embossing time reasonably,we will improve the efficiency.In the process of forming polycarbonate microneedles with the method of special hot embossing in solid-like state,the printing time is only 30?35s and the cooling time is only 2min when the temperature of upper template is 80?,the temperature of lower template is 157?,and the pressure is 12MPa.The preparation efficiency of microneedles is more than 1 times higher than that of previous methods.