The development of liquid pesticide packaging from the original off-duty bottle packaging to the present composite flexible packaging has basically gone through four stages: glass bottle packaging > polyethylene bottle packaging, polyester bottle packaging > barrier plastic bottle packaging > composite flexible packaging.
Pesticides can be divided into solid and liquid form, and liquid pesticides can be divided into water, suspension and emulsifiable concentrate. Here, we mainly discuss the packaging of EC pesticide.
Emulsifiable oil is a kind of liquid with high toxicity, strong corrosiveness and strong permeability. Therefore, as the packaging material, the packaging material must have high barrier property, which is the key point of this packaging material.
From the particularity of packaging materials, liquid pesticide packaging has experienced four stages from the original off-duty bottle packaging to the present composite flexible packaging: glass bottle packaging > polyethylene bottle packaging, polyester bottle packaging > barrier plastic bottle packaging > composite flexible packaging.
In terms of packaging barrier, glass bottle packaging is the best choice, but its disadvantages are too many, easy to break, transport takes up a large space, is not easy to recover, and now liquid pesticides tend to be efficient and low toxicity trend, so the demand in quantity is less and less. Therefore, its packaging form also gradually tends to micro packaging. At this time, composite flexible packaging materials have the space for development, and the composite flexible packaging is convenient, easy to save and convenient to transport. However, the development of emulsifiable concentrate pesticide packaging is still not mature, there are a variety of problems: the loss of efficacy, leakage, packaging materials corrosion and so on. To solve these problems, I think we must consider the following aspects:
1、 Contents
The main factor that damages the packaging materials is the solvent of emulsifiable pesticides, because the composite flexible packaging materials are generally polyethylene and polypropylene materials as the heat sealing layer. Because the solvents are generally organic solvents, according to the principle of similar phase solubility, the inner layer materials are easy to be swelled by the contents, resulting in inner layer separation. There are many kinds of solvents, which have strong penetration and corrosiveness to packaging materials. The first kind of organic solvent mainly includes trichloromethane, tetrachloroethane, carbon tetrachloride, etc.; the second kind of organic solvent mainly includes acetone, isoamyl alcohol, isobutanol, etc.; the third kind of organic solvent mainly includes gasoline, coal char, oil essence, petroleum ether, etc.
It should be noted that the strength of the solvent increases with the decrease of polarity, and the strength of the seemingly common two solvents is unpredictable after mixing together. Therefore, the experimental results must be taken as the pesticide packaging.
2、 Choice of structure
The commonly used structures are: PET / Al / CPP (PE), PET / VMCPP. PET / Al / seven layer co extruded vacuum film.
3、 Selection of raw materials
1. Selection of adhesive film:
Pet: high temperature resistance, good rigidity, good printability and high strength.
Al: best barrier, high temperature resistance.
CPP: excellent anti pollution heat sealing performance and good heat sealing performance.
VMCPP: good barrier, moisture and moisture resistance.

PE: Metallocene PE is generally used. Metallocene PE has excellent anti pollution heat sealing performance, because filling type packaging is generally adopted now, it is easy to leave content at the sealing position, thus affecting the heat sealing effect of sealing (in many cases, the leakage of contents is the influence here.) The seven layer coextrusion vacuum film is made of a variety of materials at one time. It has the characteristics of oxygen resistance, water resistance, steam resistance, oil resistance, easy heat sealing and so on. It is the first choice of pesticide packaging in China.

At present, most of the pesticide packaging structures are PET / Al / seven layer coextrusion vacuum film. It should be stated here that although the packaging structure of some contents (such as dimethoate, DMF, xylene, etc.) is the same, the final experimental results are quite different. This is because the raw materials produced in China are compared with those imported in terms of process, cooling crystallization, additive addition and surface treatment There is still a big gap in raw materials, and the aluminizing effect of aluminum coating is also very poor, which is easy to transfer. Therefore, for this kind of individual pesticide packaging, we must put the raw materials in the first place, and do not give up the cost.
2. Selection of adhesives
First of all, let's take a look at the adhesive bonding mechanism. In the composite flexible packaging, the adhesive bonding mechanism is packaged in the following aspects:
(1) mechanical meshing mechanism: the adhesive must penetrate into the crevice on the surface of the sticky material and exclude the air attached to the interface so as to produce adhesive effect. When the foam material and surface rough material are adhered to, the adhesive effect is better because of mechanical setting.
(2) Adsorption principle: since bonding is the molecular contact between the interface of two materials, the main source of adhesion force is intermolecular force, including hydrogen bond and van der Waals force. To make the adhesive well wet the solid surface, the surface tension of the adhesive should be less than the critical surface tension of the solid, If the adhesive is bridged in the depression of the surface, the actual contact area between the adhesive and the adherent will be reduced, which not only reduces the adsorption surface, but also reduces the degree of mechanical engagement.
(3) Chemical reaction mechanism
Because the adhesive wetted on the solid surface is in close contact with the adherent, a certain chemical reaction occurs between the adhesive and the surface of the adhesive, and permanent bonding is produced by intermolecular chemical bond.
According to the adhesive mechanism, the adhesive used in pesticide packaging should have the characteristics of high polarity, high cohesion and high crystallinity. Nowadays, emulsifiable oil pesticides require high efficiency and low toxicity. Their high performance depends not only on the composition of pesticides, but also on the solvents of pesticides. These solvents belong to high permeability and strong solvents, which have strong swelling properties for polymer organic polymers. The inner layer of composite materials is swelling in this case, which destroys the van der Waals force between molecules And the intercalation force between the molecules, thus damaging the inner structure of the packaging material, separating the inner membrane from the barrier layer, reducing the barrier performance of the composite, reducing the efficacy of the contents, and causing the drug failure for a little longer time.
Due to the variety of pesticides, and the variety of solvents and penetrants, as the pesticide packaging, the length of pesticide shelf life must be based on experiments. According to different pesticide ingredients, seven layer and nine layer coextrusion vacuum membrane of different materials should be produced to meet different packaging 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.