Preparation And Application Of Microcapsules With Loading Of Uv Absorber And Investigation Of Its Property

Appropriate exposure to sunlight is conducive to health,but a long-term exposure to ultraviolet radiation will destroy the skin surface cells and the dermis,which cause skin aging,loss of elasticity,dark spots,wrinkles,even skin diseases such as hair folliculitis.In order to protect the skin from the harm of ultraviolet ray in sunshine,there are plenty of sunscreens used to absorb or refract UV on market.Moreover,even various kinds of daily cosmetics to which sun-proof agent used not to be necessary now contain UV-screening agent(ultraviolet absorption agent).Those products manufactured for sun block,including cream,liquid foundation and BB cream etc,contain highly concentrated UV screen agent(UV absorption agent),which is able to hike up the value of SPF during a short period of time.The price of UV screen agent is relatively lower and convenient to mix,therefore it's able to meet the maximum economic benefits of manufacturers.However,most UV screens(such as UV absorbents)are organic chemicals that can cause skin allergies even cancer.In order to obtain a higher SPF and reduce the damage caused by cosmetics to the skin,an efficient encapsulation technology--microencapsulation technology is in urgent need.The microcapsule technology can not only isolate the uv blocking agent(such as UV absorbent)from the skin by covering the core material with the polymer wall material,but also reduce skin allergy.At the same time,it can also protect the coated UV shielding agent(such as UV absorbent,etc.)core material from external environment(such as light)interference and enhance its stability,thereby enhancing the sunscreen performance(SPF).In addition,the spherical structure of the prepared sunscreen microcapsule can eliminate part of the ultraviolet rays by refracting and other physical means,realizing the dual effect of physical and chemical sunscreen.The function makes microcapsule have a much broader market in the field of daily use cosmetics.In this article,with the benzoyl peroxide(BPO)as initiator,precipitation in free radical polymerization between poly(ethylene glycol)diacrylate(PEGDA)and Ethyleneglycol dimethacrylate(EGDMA)was initiated to coat the mixture of core material compounded with four kinds of UV absorbent(Avobenzone(AVO),Octocrilene(OCT),homosalate(HMS)and2-Ethylhexyl salicylate(ETH)),thereby preparing microcapsule with function of ultraviolet absorption.In order to determine the best process conditions and the best formula ratio,this study mainly focuses on the factors such as the proportion of core materials that affect the performance of sunscreen,the amount of sunscreen microcapsules added to sunscreen cream with UV absorption effect and the finishing on fabric,etc.The properties of the microcapsules were characterized,including particle size distribution,morphological characteristics,thermogravimetric analysis,embedding rate and chemical composition.The results showed that the external morphology of the sunscreen microcapsules was spherical structure with smooth surface.The average particle size distribution of the microcapsules was 3.02?3.46 ?m.The coating rate of the sun protection microcapsule was 85.24%?89.82%.The sun protection performance(SPF)of sunscreen microcapsules was measured by the UV transmittance analyzer.It can be seen that the sun protection performance of the microencapsulated UV absorber increased exponentially compared with that of the unencapsulated UV absorber core material.