Milk is a very common food in our daily life. But I do not know if you have paid attention to the form of milk packaging, especially the form of soft packaging. This paper will briefly analyze the soft packaging of milk, hoping to inspire the friends who are ready to join the relevant industry.
The common milk soft packaging is divided into two categories: full plastic soft bag packaging and paper plastic composite packaging. These two categories can be further subdivided into several different types. We will introduce them one by one.
Film knowledge: on soft package of milk
Pure PE black and white film
Pure PE black and white film is the earliest form of milk soft packaging. Generally, it is produced by three-layer co extrusion and blowing process. According to the equipment conditions, five layer or even seven layer coextrusion structure can be used for production. As the name suggests, the film is white on the outside and black on the inside. The purpose of this design is to carry out surface printing on the outer white background; at the same time, the black on the inner side can achieve a certain light shielding effect and prolong the shelf life of milk. Milk is a high value content, so the strength of packaging is required. Therefore, we often use 1mi linear with a small amount of low melt finger high pressure production, and add a certain amount of metallocene in the heat seal layer to ensure the heat sealing effect.
EVOH co extruded black and white film
Compared with pure PE black and white film, EVOH barrier layer is added into EVOH coextrusion black and white film. Therefore, at least five layers of coextrusion structure are needed for production. In fact, many manufacturers have been using seven layer coextrusion structure to optimize the functional design of each layer. The choice of adhesive resin is an important factor in the formulation design of EVOH coextrusion black and white film. Improper selection of adhesive resin will cause EVOH insufficient adhesion, delamination and water ripple. Compared with pure PE black-and-white film, the barrier property of EVOH coextruded black-and-white film has been greatly improved. Therefore, it is commonly used in summer and autumn, when the temperature is higher.
Roof bag
The roof wrap is named after its sloping design that looks like a roof at the top. This kind of milk packing appearance is beautiful, the shelf display effect is good, and easy to open. Packaging material structure is simple, generally PE coated paperboard. Only because of the high processing temperature of PE coating process, it is necessary to select low odor coated PE production. Because there is no barrier, the roof bag is only suitable for pasteurized milk that needs to be stored in cold storage.
Tetra Pak
Tetra Pak is a rapidly developing milk packaging form in recent years. It is a paper aluminum plastic composite structure packaging invented by Tetra Pak company. According to the shape, it can be divided into tetra Lok pillow, Tetra Pak brick, Tetra Pak diamond, etc. Due to the expiration of Tetra Pak's patent, a large number of domestic Tetra Pak manufacturers have sprung up in China in recent years. The packaging materials of Tetra Pak are processed in one time by multi head coextrusion coating process.
The first step: the paper / LDPE / aluminum foil structure is obtained by bonding the printed paper with aluminum foil through LDPE coating;
The second step is to obtain the structure of "paper / LDPE / aluminum foil / EAA / heat sealed PE" by CO extrusion and coating on the aluminum foil side;
The third step: coating LDPE on the outside of the paper to get the final product structure of "LDPE / paper / LDPE / aluminum foil / EAA / heat sealing PE".
In particular, the heat sealing strip is used to enhance the strength of the back seal.
Kangmeibao
Kangmeibao was invented and promoted by sig. The structure of Kangmei bag is similar to Tetra Pak, so it can be produced by the same multi head co extrusion equipment in theory. But generally speaking, the paper thickness of Kangmei package is thicker, and due to different heat sealing methods, Kangmei bag has different requirements for heat sealing PE. The heat sealing of Kangmei package is realized by using hot air to blow the hot surface, so the requirement for the low temperature unsealing performance of the heat seal layer is higher. Therefore, the heat sealing PE of Kangmei package generally needs polyolefin plastic body to meet the requirements.
Dongguan Beite packaging materials Co., Ltd. - located in Dongguan City, the world's manufacturing city, is a subsidiary of Beite packaging (China) Co., Ltd., with a plant area of 6000 square meters. It is a flexible packaging enterprise integrating R & D, production and sales. It has a complete set of domestic advanced production equipment, a scientific and humanized management system and a group of experienced technical personnel For backing, to provide customers with quality products and first-class service.
The company produces composite bags, roll film, fruit bags, aluminum foil bags, suction mouth bags, self-supporting bags, zipper bags, anti-static bags, special-shaped bags, etc., which are suitable for the internal and external packaging of food, daily chemicals, electronics, toys, medicine, cosmetics, industrial products and other industries.
We uphold the integrity of cooperation, good quality, good service business philosophy, won the industry's approval, products sold to all over the world; welcome friends from all walks of life to inquire, visit our factory to investigate guidance and business negotiations.