DuPont Co., which has been committed to developing packaging materials with high-tech means, has recently recommended reliable AE high-performance adhesive resins that have just been developed to various countries in the world.
Soft composite packaging materials have been used in food, pharmaceutical packaging and other fields for more than 50 years. In addition to the co-extrusion compounding process, the extrusion compounding process and the dry compounding process are the main methods for producing this material. However, there are always two issues in any matter. These two processes have obvious deficiencies in some aspects. For example, in the extrusion compounding process, LDPE and aluminum foil are often not bonded tightly; in the dry compounding process, cracking of the aluminum foil often occurs or the adhesion fastness due to too much residual solvent is not good, and therefore often Cannot be used for food and medicine packaging. The use of a composite film produced by the AE extrusion-composite process has many advantages.
First of all, since only a small amount of primer is needed on other substrates during compounding, the desired interlayer adhesive strength and complete packaging structure can be obtained at lower cost.
Secondly, AE compliance is in compliance with the relevant regulations of the US Food and Drug Administration (FDA). There is no residual solvent problem that often occurs in dry compound processes. Therefore, the composite film made of AE is suitable for food and medicine packaging.
Again, in a typical structure using a strong AE, an adhesive layer consisting of LDPE + AE-reinforced compound is laid between aluminum foil and aluminum foil, or between aluminum foil and PET or OPP, between aluminum foil or aluminum foil and others. The soft contact between the substrates allows the aluminum foil to be effectively protected from cracks that are common in dry compounding.
The advent of DuPont's AE high-performance adhesive resin has solved these problems and subtly compensated for the inadequacies of the extrusion compounding process and the dry compounding process.
Robust AE is an ethylene-methyl acrylate-acrylic terpolymer that can be used on ordinary extrusion coating, co-extrusion coating, and extrusion compounding equipment designed to process polyethylene resins. After mixing with 20 parts of AE and 80 parts of LDPE and mixing evenly, the bonding strength of PET or OPP film with aluminum foil or a small amount of primer can be improved in the extrusion composite process.
Under appropriate processing conditions, the initial value of the interlayer peel strength of the composite film obtained by using the LDPE+ AE-reliable mixture instead of the pure LDPE and the extrusion composite process can reach 2.5 to 3.0 N/15 mm. The final value of the peel strength after standing for a period of time can reach 3.0-3.5N/15mm. Obviously, its reliability and integrity of the barrier are guaranteed.
Most compounding devices have only one glueing device and cannot produce PET (OPP)/LDPE/aluminum foil structures. The reliable AE can make the LDPE and aluminum foil have a good fastness, which makes it possible for ordinary extrusion composite equipment to produce such a structure.
The United States DuPont's general agent in East China, Shanghai Sibang Trading Co., Ltd. General Manager Mao Yufeng told reporters: Polymer blending is a simple and effective modification process in plastic processing, using DuPont high performance adhesive resin AE and reliable LDPE blending can effectively improve the adhesion of LDPE.
Without changing the original production process, the blend is used to manufacture PET (OPP)/substrate (small amount)/LDPE+AE/aluminum foil, and aluminum foil/LDPE+AE/aluminum foil structure. The resulting composite film product is at a price. The peel strength, the integrity of the package, the reliability of the barrier, and the mechanical strength are all satisfactory. (Yu Weimin) (From "China Packaging News")