Abstract: this article briefs on the necessity of package barrier property test. It also presents the functions and services of Labthink Lab.

With the improving of people's living standard, the demand on consumables package is constantly increasing. The earlier requirement on durability and later on beauty now turns to aspects of package function and package safety. At present, domestic testing of package materials cannot satisfy these test requirements yet. Moreover, the test level of some material manufacturers and corresponding users is very weak. Therefore, to mitigate the irregularity situation of test items and test standard, from this year on, relating institutes has issued compulsory test items to the production and use of food package materials.

1 Test Demand

Since there is external packing outside flexible package, many people are unwilling to attach importance to the test of flexible package. This is because on the one hand some package practicants do not have enough knowledge of the importance of package testing. On the other hand, some manufacturers mistook that the adopting of package materials can improve certain properties of the finished products. For example, for food package that requires high barrier property and lucifuge, complex materials containing aluminum become the favor of some manufacturers, who takes it as perfectly safe measure. Speaking in the perspective of microscopic permeation, the barrier property of aluminum foil is much high than that of organic barrier materials. But it is more easily to appear pinholes and creases. (The number of pinholes relate with aluminum thickness. Generally pinholes can be avoided only when the thickness exceeds 16m. However, the increase of thickness will greatly increase product cost). Bending or impacting of materials during production and application may result in flaw of aluminum, which in turn result in obvious decrease of barrier property of materials and is unable to meet package requirements. Flaw materials without barrier property test may result in extremely high content of inner oxygen and water vapor, which will cause food deterioration. That is why even the selection of high barrier materials cannot lower the demand on property testing of finished products

Functional packing materials possess special protective functions, such as high barrier property, environmental degradation, antistatic, editable and other special functions. At present, in terms of food package, barrier materials attract the most attention in functional materials. This is because barrier materials can prolong quality guarantee period of inner content more effectively by controlling the internal-external content and exchange rate of gases such as oxygen, nitrogen, water vapor and etc and by adapting to special packing forms such as controlled atmosphere package and vacuum package. Barrier property test is the most advanced test item in present physical property test of materials. Now as our country is attaching more importance to safety of food package, more and more quality check institutes, scientific research institutes, material manufacturers as well as relating departments are purchasing barrier property testers to intensify their test

Being the first domestic manufacture of package test instruments that sets foot in barrier property test, Labthink not only had products relevant to physical property test of many kinds of materials. It also possesses barrier property testers manufactured according to many test methods (its instrument executive standards covers eight barrier property test methods in the world). Because barrier property testers are high in price and because common package users have acquainted the concept of barrier property only in recent years, these instruments are not well popularized in our country. At the same time, domestic agencies that can test for commission are not many. All that hinders domestic package material manufacturers to reasonably adopt rather expensive barrier material. To better research barrier property test instruments and to accumulate rich material test experience, Labthink begin to formally establish barrier property lab in 2000 to provide customers with professional barrier property test service.

Moreover, this lab can perform auto gas and water vapor permeability test under various temperatures. Among that, equal-pressure oxygen permeability test instrument and sensor method water vapor permeability testers have particular advantage in temperature controlling. The lab can carry out integral oxygen permeability test and water vapor permeability test of package. While researching its own subjects, Labthink barrier property lab is carrying out data comparison for various test methods. Part of the research achievements is published on some academic journals. Up to 2005, Labthink lab has provide multiple-level professional services to more than 2000 customers in the world. It has data comparison and data exchanging business with world known packing labs such as Germany MECADI lab and Thailand packing center

 One thing worthy mentioning here is the barrier property test of package. Package is the common form used in liquid packing. Its special shape made the barrier property testing rather difficult. In the past, gas permeance is estimated by testing sheet material of package. However, there is obvious disparity existing between estimated and actual gas permeance of the package. Among various test technologies, package oxygen permeability enjoys the rapidest development. The introduction of standard ASTM F 1307 for package oxygen permeability test not only accelerated the research and popularization of package oxygen permeability instruments. Test results also become more scientific and accurate. In 2004, Labthink developed the first domestic package/film oxygen permeability tester. Based on electrochemistry principle and possesses double function of film test and package test, this instrument meets the requirements of ASTM F 1307 and ASTM D 3985. This year, basing on its successful developing experience of package/film oxygen permeability tester and combining with its water vapor permeability instrument developing experience, Labthink introduced the TSY-W3 for package water vapor permeability test. This instrument adopts electrochemistry principle and is accurate in humidity and temperature controlling, which can effectively avoid the influence on test data caused by the difference of constant temperature and humidity controlling in gravimetric method. This kind of instrument provides a favorable test method for the comprehensive understanding of package barrier property. At present, barrier property lab has provided barrier property test service to customers home and abroad with satisfactory test results.

Package safety is essential to food safety. At present, unpacked food is becoming less and less, while package forms relying on the property of packing materials are obviously increasing. Adopting barrier materials reasonably can efficiently prolong quality guarantee period of the food. Barrier property test can provide great help to the selecting of packing materials and to the designing of packing structures.