Analysis of pearlescent film used in the packaging

Analysis of pearlescent film for cold drink packaging (Part 1)

Abstract: BOPP pearlescent film/CPP, BOPP pearlescent film/PE with general compound structure are often used in cold drink packaging, such as ice cream, cooked label, sweets, biscuits, snacks, etc., because they share certain pearlescent fruits. This paper discusses the pearlescent film used in flexible packaging, analyzes the common problems in the use process, and looks forward to the technical exchange and help of peers

1 characteristics and application of pearlescent film

at present, the domestic cold drink packaging has been developed by leaps and bounds, realizing the diversification of cold drink packaging forms and product functions. According to relevant reports and data, cold drink packaging accounts for 23% of flexible packaging. At present, some flexible packaging color printing enterprises are focusing on cold drink packaging processing, aiming to build professional brand enterprises. According to relevant data, China's cold drink packaging is currently developing at a rate of 30%. Senior experts predict that the rapid development of cold drink packaging will not only drive the development of related industries, but also allow flexible packaging enterprises to see broad prospects. Cold drink packaging is gradually changing from the previous single-layer plastic film packaging to multi-layer packaging. Its functionality such as barrier and ultra-low freezing are better, and its structure is also diversified, such as BOPP/BOPP (pearlescent), BOPP (pearlescent)/PE, BOPP (pearlescent)/CPP, etc. At present, cold drink packaging is developing in the direction of high-grade, such as PET/Al/CPI, PET/CPE, PET/L/NY/CPP (CPE), which not only requires that the properties of packaging products meet the requirements of Taiwan quality fumigation, so as to ensure that the contents do not deteriorate. At the same time, it also puts forward higher requirements for related materials such as ink, film, composite adhesive, so as to measure the friction force received on the pin when sliding. And the famous brands such as Luxue and Yili in the former market: Lingyin packaging products are a good example. BOPP, pearlescent film has become the new favorite of packaging now, mainly because of the excellent barrier property of this material. At the same time, because this film material adds a certain amount of CaCO and pearlescent pigments in the actual production and processing process, it has a certain pearlescent effect and strong decoration. Pearlescent film will not be measured accurately at that time. China's development history is not long, but the demand for packaging is developing rapidly. Pearlescent film is made of polypropylene resin as raw material, added with carbonic acid, which is widely used in calcium and pearlescent pigments. After mixing, it is formed by biaxial stretching. Due to the mechanical foaming method, the specific gravity of pearlescent film is about 0.7, while the specific gravity of PI is about 0.9. Therefore, flexible packaging enterprises are willing to choose it because of its low price, good decoration and excellent performance. If you want to make a heat sealing bag with good peel strength, you must carry out lamination, that is, lamination processing. In the actual production process of pearlescent film, the particulate CaCO masterbatch is evenly dispersed in homopolymer pp. when PP is stretched, many holes are formed. It is these LRQ refracted rays that form the pearlescent effect. In addition to the heat sealed pearlescent film JLP, there are three layers of copolymerized non heat sealed Bopi pearlescent film, that is, two layers of homopolymer PP with a pearlescent layer. In fact, bOBP pearlescent/Ldie (CPP) is often used to meet our customers. BOPP, pearlescent film has silver pearlescent color. It can reflect more light, and its gas and water resistance are also better than other BOPP films. The double-sided heat sealing pearlescent film BOPP with a thickness of 35ui1i can be directly used for the packaging of cold drinks such as ice cream and ice cream, as well as the protective packaging of candy pillow packaging, chocolate and soap. The double-sided cooked BOPP pearlescent film with a thickness of 30um is widely used in the packaging of biscuits, sweets, sweets, snacks and other snacks. In addition to the application of BOPP pearlescent film in soft packaging, a considerable part is used in gift packaging. A delicate small ribbon can express friendship. The wide use of pearlescent film in cold drink packaging is mainly related to its economy and its own characteristics

2 printing and compounding of pearlescent film

the purchase of pearlescent film must be tested: the corona treatment value must meet the quality requirements, but the most important thing is to test the pearlescent reflection effect. Our method is to take a piece of pearlescent film, hold the material in the light transmission place, let the light pass through the experimental line under the specified experimental conditions and requirements, and move the film surface left and right, we will find the distribution of pearlescent. Sometimes it feels dark and yellowish; Sometimes it feels silver. If we compare two pearlescent films from different manufacturers, it is easy to find the problem. We suggest that enterprises should choose films with good light reflection instead of yellowish films and other materials that do not meet the quality requirements. Because now the cold drink pearlescent film composite products have a common phenomenon, that is, there is little ink on the printing, and the color of the pearlescent film will be directly reflected in the printed products. The protection of pearlescent film is also very important. Generally, the pearlescent film to be used should be placed at the ventilated dry coal and wrapped with pet. Improper storage will have a certain impact on the composite performance.

the pearlescent film printed by gravure printing generally adopts double-sided heat sealing film, and the gravure printing ink generally adopts polyamide surface printing ink, but also adopts inner printing ink. The printing sequence generally adopts the method of table printing, that is, yellow or red is printed first, and then black is printed. Printing B, -j-~~ meaning tension control and drying temperature control; In addition, the winding of pearlescent film is also very important. It is recommended not to tighten it too tightly to prevent adhesion failure. Now the winding device of gravure printing machine has evolved from the original manual adjustment of spring control tension to the use of electronic frequency conversion automatic control (such as the equipment of Guangdong Shanzhang machinery and Zhongshan Songde machinery). Common faults of printing pearlescent film are:

1) color biting

color biting phenomenon is that the ink of front to color printing is anti glued to the printing plate of the next color during overprint, and the color of the previous color can be obviously seen on the latter color

reasons for biting color:

① the ink of the previous color is not dry enough, and the drying speed of the next color is fast, resulting in an instantaneous increase in viscosity, which sticks the previous color down

② the solubility of resin in the ink is too good, which makes the ink easy to dissolve again

③ the printing speed is too slow, which makes the pattern part of the printing film stay on the printing plate for a long time

④ the pressure of the impression cylinder of the latter color printing is too high

solutions to color biting:

① use fast drying solvent for the former color to improve the dry coal rate of the former color

② improve the printing speed

③ blow to the second color layout

④ reduce the printing pressure. Replace the ink