Study On The Preparation And Barrier Properties Of Co-extruded Five-layer Composite Hose For Cosmetics

With the features of hygienism,convenience,low cost and easy to carry,the plastic packaging is being widely used in the field of cosmetic packaging.Especially,the composite plastic tube made by the five layer coextrusion methods,with multiple specialties,shows the better barrier property.And,the ethylene-vinyl alcohol copolymer(EVOH)is often selected as the material for the barrier of the five layer composite plastic tube.EVOH performs very well as oxygen barrier but poor as water resistance barrier,and it gets even worse in high humidity environment,because the oxygen barrier property is obviously dragged down by the moisture absorption feature of EVOH,due to which,the water vapour barrier performance improving is in urge need for the five layer composite plastic tube.This paper demonstrates a method,which exploits the specialty of high water vapour resistance of the COC,and successfully produces a COC modified LLDPE composite tube.The experiment result indicates that the higher content of the COC in the tube,the higher performance in the modulus,strength and Tg,while in the same time,with higher melting enthalpy change,it requires a higher processing temperature.However,with higher content of LLDPE,the samples indicates higher elongation at break.When the COC content of the outer layers of the composite tube gets greater than20%,the performance as water vapour resistance and oxygen barrier is able to fulfill the requirement.The delamination strength tests on the the produced six samples of five layer composite tubes(C1-C6),indicates the impossibility of delaminating and reaches the expected target in such aspect.However,all six samples is unable to fulfill the environmental cracking requirement,since the inner layers are made of LDPE.With the LLDPE modified LDPE,it successfully produces LLDPE modified composite tube,improves the performance in the environmental cracking.The experiment results proves that,with higher LLDPE contents in the inner resin,the higher in the crystallinity and melting enthalpy change it will be,which leads to the requirement of a higher processing temperature.However,with the contents of LLDPE gets higher in the sample,the mechanical performance declines.When the COC content of the inner layers of the composite tube gets greater than 20%,the performance as water vapour resistance,oxygen barrier and environmental cracking is able to fulfill the requirements.The delamination strength tests on the the produced six samples of five layer composite tubes(D1-D6),indicates the impossibility of delaminating and reaches the expected targets,which is as below:the oxygen permeation rate less than 2.0cc/(m~2�24h)and water permeation rate less than 0.6 g/(m~2�24h).In the six combination,D3 sample fulfills the requisite targets in the barrier property,processing,environmental cracking and cost,and indicates best mechanical performance,which is the best selection in all combinations.