There are different kinds of masks for different purposes: deep-cleansing, by penetrating the pores; healing acne scars or hyper-pigmentation; brightening, for a gradual illumination of the skin tone.
Moisturizing skin is one of the main functions of the facial mask. The water contained in the essence of facial mask can keep the skin wet. Therefore it is a critical issue to minimize the loss of water inside the essence of facial mask.
Currently aluminum plastic composite package, glass jar, plastic jar and plastic tube are used as the main packages for facial mask. No matter what kind of package is used, the packaging material must have adequate water vapor barrier property so that the water inside the essence of facial mask can preserved properly. In this article, we take aluminum plastic package as an example to provide simplified testing procedures for water vapor permeability of facial mask package for your reference.
There are mainly two categories of test methods for water vapor transmission rate i.e. gravimetric method (also known as cup method and divided into dry cup method and wet cup method) and sensor method (including electrolytic sensor method, infrared sensor method and humidity sensor method).
The testing instrument used in the tests mentioned in this article, Labthink W3/330 Water Vapor Transmission Rate Test System adopts electrolytic sensor method. With electrolytic sensor method, the specimen is sealed in a transmission cell, which is divided into a dry chamber and a controlled-humidity chamber. The dry side of the specimen is swept by a flow of dry carrier gas, and water vapor permeating through the specimen from the controlled humidity chamber is carried by the carrier gas into an electrolytic cell, where proportion electrical signals will be generated. The water vapor transmission rate is obtained by analyzing and calculating the electrical signals.
The tests can be performed according to the following procedures.
(1) Cut 3 pieces of 108mm by 108mm specimens with sample cutter from the aluminum plastic composite package for facial mask.
(2) Face the aluminum foil side of the specimens towards controlled humidity chambers. Tighten the test cells with hand.
(3) Set test parameters and specimen parameters in software.
(4) Adjust the pressure of carrier gas (nitrogen) and make the humidity inside the test chamber reach preset value. By turning the flow switch valve, make the nitrogen flow meet requirements.
(5) Start test and the test will be performed automatically. The instrument will record the change of water content in dry chamber and calculate the test results automatically.
According to the test results of water vapor transmission rate, the manufacturers or users of the facial mask packages can determine whether the packaging materials can be used to prevent the loss of water inside the essence of facial mask. And through water vapor permeability tests, the manufacturers of facial mask can select the most suitable packaging materials to guarantee the quality of their products.
About Labthink Instruments Co., Ltd:
Labthink Instruments Co., Ltd is one leading supplier of packaging testing instruments, which is headquartered in Jinan, China and operated in Boston, U.S.A.