The thickness uniformity of flexible packaging materials plastic packaging design and packaging costs
?With crude oil prices continued to rise , the cost of polymer packaging materials also rose sharply . Today, however, the intense competition in the market , because if prices of packaging materials and increase the selling price of products in an attempt to increase the cost of all or part of the turn added to the consumers, consumers certainly do not buy . In addition, if the manufacturer trying to reduce costs by reducing packaging performance , which is nothing short of dismantling their signs. Current approaches can effectively solve the rising costs of packaging materials have the following two aspects : first, intensify the development of new polymers, to reduce as much as possible without reducing the amount of packaging material or reduce the cost of packaging performance under the premise ; followed by taking effective means to control the uniformity of the test material thickness , reducing packaging waste resulting rate . The latter relatively easier to implement , thickness measurement using the existing technology can help companies reduce packaging costs.

1 , the importance of uniformity of the film thickness

Thickness uniformity is one of the prerequisites for the protection of materials with specific functions . plastic packaging box In functional barrier material , for example, the barrier layer will directly affect the uniformity of the overall barrier properties of the material . The barrier layer is a barrier layer of the film is the most important , the barrier properties of the barrier film on the one hand the level depends on the clear plastic packaging choice of barrier layer material ( e.g., excellent barrier properties of the current blocking layer materials which are mostly aluminum , aluminum , silicon oxide coated material , PVDC, EVOH , etc. ) ; other depending on the thickness of the barrier layer , the barrier layer is generally thicker the better the barrier properties of the film , when the thickness of the barrier layer reaches a certain level , the barrier properties of the film has become stable , no longer increases with the growth of the barrier layer thickness. Barrier materials are expensive , the thickness of the barrier layer directly affects the overall costs of the barrier film . Application of multi-layer composite film can effectively reduce the packaging cost , wherein the thickness of the barrier layer is only about 10% of the overall thickness of the film , some even only 5m ( or less ) , but difficult to control the thickness of the barrier layer is very large . When the thickness uniformity of the barrier layer is not prone to weak points in the function of the barrier layer , resulting in instability of the entire film barrier properties , poor barrier properties may be part of the packaging material , the resulting product should reach the expiration date , and for part of the film ( especially good transparency film ) barrier layer film thickness changes also affect the overall appearance and vac tray color , reduce the display of goods .

Film thickness uniformity or not will give film printing process and the corresponding increase in the use of difficulty . In commonly used in gravure printing , for example, control the printing of the critical tension to ensure print quality , control and tension the film material , the thickness and uniformity of the thickness have a relationship , caused by poor control of the overlay material can be directly allowed . Further , the film thickness uniformity can also cause poor dislocation phenomenon rewinding the film after printing.

In the production process of multilayer films , the film thickness of any layer can cause uneven unevenness subsequent processing , resulting in the finished film thickness uniformity is worse . Use of this uneven film thickness for packaging , packaging materials when using the mechanical properties of weak points prone , if the packaging , transportation , storage, packaging, sales process, subject to greater external shocks, these weak points prone to cracks , holes and other special save function resulting material is reduced or completely lost .

2 , how to detect the film thickness

Manufacturing and processing of the film , the film thickness detection is one of the most common detection index film , a film thickness detecting the addition into the coating thickness and the thickness detector detects two types . Since the thickness of the film is the total thickness of the resin layers , if the overall difference in the thickness uniformity of the film , wherein the thickness of the resin distribution layers may also differ . Undoubtedly , the detection of the thickness of the coating will be more conducive to effective control film thickness uniformity of the layers , but get the most accurate measurement for each of the multilayer film thickness of the coating on the respective detection equipment need to have a thickness very large investment , and with the growth of the thin film layers increase , to bring greater economic burden. More economical way is expensive coating material portion for detecting the thickness of the coating , while enhancing the overall film thickness uniformity is required to achieve effective control of the role of other layers of material thickness.

Thickness testing equipment can be divided into online thickness measurement equipment and non- line thickness measurement equipment into two categories, these details can be found in two types of devices , ” commonly used method for measuring the thickness of the film ,” a text . If these two types of thickness measurement can be used in conjunction with the device is the best , this is due to line thickness measurement equipment is often used in non-contact measurement, can not be avoided because the material has a compression or a soft bag for the thickness of the material detected is caused by poor surface flatness volatile data , the line thickness measurement device can not provide a contact measurement method ( eg Labthink CHY-C2 uses a mechanical thickness measurement method ) , makes up the line thickness measurement of this a shortage . Although other line thickness measurement can control the film thickness uniformity of the batch , but the finished film is not suitable for sampling must therefore be equipped with a non- line thickness measurement device.

Line thickness measurement device with the fastest speed to get the thickness of the test data , and adjust parameters production line to reduce the thickness fluctuations in material and shorten the production line driving time , but need to be equipped with production lines that match the scanner , which its reuse have certain restrictions, and the price of equipment, operation and maintenance costs to be much more expensive than non -line thickness measurement equipment. Non- line thickness measurement devices are inexpensive , small , easy to use , but the production line thickness parameter adjustment feedback is much slower. Non- many types of online thickness measurement equipment , including mechanical thickness measurement technology applicability of the strongest , it is not selective samples tested free from color products, ingredients change on or reflective surfaces can be used to detect any substance, and plastic trays it in the same thickness measurement will apply some pressure to measure the surface of the sample, which can effectively avoid data due to the compression or samples with poor surface flatness plastic box caused by the volatile situation , very suitable for soft packaging materials thickness detection . Further, since the compressibility characteristics of the film , when the thickness of the detection of various types of thin film with a thickness of the case is often a gap appears , therefore , strict accordance with a predetermined condition is important plastic packaging to select the instrument .

3 , outlook
Increase the thickness uniformity of the test material , can reduce scrap packaging materials , to achieve the purpose of saving costs. Due to the compressibility of the structure of the soft package material itself , making the gauge has been the first choice for all types of machinery and soft packing material thickness detection. However, the mechanical contact type thickness measurement method Measurement limit its clamshell packaging development in the field of line thickness measurement , and therefore , in order to effectively control the thickness uniformity of the material , preferably simultaneously with the line thickness , and non -line testing equipment , which according to the needs of enterprises combination of factors, type of material , thickness uniformity control requirements , the equipment budget to decide.