EC pesticide plastic bottle features

Pesticides are divided into two types: solid and liquid, and the liquid can be divided into liquid agent, suspension concentrate and emulsifiable concentrate.

People who understand the nature of pesticides know that, in general, ordinary polyethylene (PE) plastic bottles can be used for filling liquids and some suspensions, but they cannot be used as packaging for EC. Otherwise, the organic solvents in the EC pesticides will escape through the molecular gaps in the plastic bottle wall, and they will be investigated and dealt with by relevant national agencies due to weightlessness. Therefore, such plastic bottles are rarely used in the packaging of EC pesticides.

Another type of plastic bottle, the PET bottle, is different. It has a barrier effect to certain organic solvents, so it is not only widely used in pesticide packaging for water and plastic suspensions, but also for packaging of some EC pesticides. However, there are some obvious deficiencies in this material. First of all, it does not have sufficient barrier effect on moisture, and the finished EC pesticide products often cause the decomposition of pesticides due to the moisture in the environment. The newly revised national standard "Agrochemical EC packaging" has been implemented since March 1, 2001. "There are specific restrictions on this. Second, the PET bottles will be miscible with certain pesticides or auxiliaries, and the bottles will become soft and deformed. Typical varieties include "dimethoate" and "dimethylformamide (DMF) solvent".

It is precisely because of these two kinds of plastic bottle packaging that there are such deficiencies, the last century, the end of the 1990s, the domestic pesticide market began to appear specifically for the packaging of emulsion pesticides bottle.

Barrier plastic bottle types and their respective characteristics

The so-called barrier plastic bottle refers to the use of a special treatment process (or at the same time combined with a special material), so that the treated plastic bottle has the function of effectively blocking the penetration of organic solvents in the EC pesticide, while retaining the The plastic bottle itself has a light weight, a variety of different shapes (various shapes), non-friable and other special properties of the special plastic bottles.

In general, barrier plastic bottles can be roughly classified into three categories:

1. Fluoride Barrier Bottle

The barrier plastic bottle that was first introduced into China and formed a mass production supply was "in-mold fluorinated plastic bottle."

The "fluorinated bottle" technology was first invented by American Air Products and developed by British Boxmore. In the mid-1980s, this "in-mold" or "online" fluorination technology won the Queen's Award for Innovation in Science and Technology.

The first fluorination technology called “post-line fluorination” technology refers to the first blow molding of polyethylene (PE) plastic bottles, and then storing the plastic bottles in a closed container, filling the container with a certain percentage of “fluorine for a certain period of time. "Nitrogen mixed gas" forms a layer of fluorinated layer mainly composed of PTFE on the inner wall of the plastic bottle, so as to achieve the effect of blocking the organic solvent.

Dr. Morris has developed this technology as an "in-mold" or "online" fluorination technology, that is, fluorination is performed simultaneously in the blow molding process. This technology greatly improves the fluorination effect and production efficiency, making plastic bottles more economical than other types of barrier bottles.

However, the economy of fluorinated bottles is a prerequisite. That is, at the initial stage of production, there must be a considerable amount of investment to form a matching production scale. If the fluorination system is fully automatic computer controlled, it must be matched with a considerable amount and capacity of blow molding equipment to achieve economies of scale. Second, the fluorination process requires a high-purity and consistent ratio of fluorine-nitrogen mixed gas, and a specific performance (grade) of polyethylene raw materials to be matched.

Under normal circumstances, the fluorinated barrier bottle in the international market is tens of percent lower than the cost and price of the other two barrier bottles. This is why the introduction of fluorinated bottles was the first reason.

2. Blending barrier bottles

Blending barrier bottles were first developed by DuPont in the United States in the 1980s and are called Selar RB technology in English. Refers to a barrier bottle that will contain impervious organic materials such as nylon (PA), polyvinyl alcohol (EVOH), etc. mixed into common polyethylene and blow molded.

The advantage of this technology is that it can be extended with ordinary blow molding machines, and its screw can be put into production with slight improvement. Therefore, the equipment investment for this technology is relatively small. This is its main advantage.

However, the application of this technology is more complicated. Its barrier effect depends on the degree of mixing of two different materials. When the kneading is insufficient, the barrier effect of the polymer (such as nylon, etc.) does not sufficiently extend, and the barrier performance is improved little; when the kneading is too strong, the barrier polymer is broken into fine particles dispersed in the matrix and completely lost. Barrier performance.

DuPont Co., Ltd. of the United States has a more mature solution to this problem. It is alleged that if a considerable amount of fees is charged, the relevant technology may be transferred. At present, some domestic Japanese-funded enterprises have such a supply of blend bottles, but they cannot be promoted in the pesticide industry due to high costs.

A domestic research institute said that similar technologies have been developed and that the asking price is RMB 100,000 yuan for transfer. But the premise is to purchase its blended blend (20,000 yuan/ton). It is understood that domestic manufacturers that really use their technology and form mass production have yet to be discovered.

3. Co-Extrusion Barrier Bottle

Co-extrusion comes from the English Co-extrusion, often abbreviated as Co-ex. The main feature of this technology is the bonding of two plastics with different physical and chemical properties (generally polyethylene and nylon or polyvinyl alcohol) with special adhesives. Thus, the plastic bottle is composed of at least three layers. Among them, nylon, polyvinyl alcohol and the like having a barrier effect are generally located in the innermost layer.

These materials, including special adhesives, are available on the market, and their performance is directly proportional to the price. Therefore, the material is not the bottleneck of this technology.

The problem lies with the device. Unlike ordinary blow molding equipment, blow molding equipment for multi-layer co-extruded bottles must be configured with different numbers of screws and extrusion heads depending on the number of layers. The minimum configuration must be a triple screw and a corresponding triple extrusion head. Not only that, each extrusion head must also have an adjustable range and ensure good product consistency. As a result of these requirements, only a handful of manufacturers can provide the equipment that meets the requirements, and the price of their equipment is correspondingly unattainable.

This is the reason why there are only co-extruded equipment and co-extruded bottle manufacturers in the world, and why the price of their products is more than tens of percents of fluoridation barrier bottles.

This situation has now undergone dramatic development.

Since 2002, there have been five or six co-extruded bottle manufacturers in a certain place in Zhejiang, China. It is understood that among these, there are Taiwanese equipment that are used to produce useful equipment from South Korea and Germany, and there are also claims that the United States imports equipment without allowing any outsiders to visit. What is amazing today is that these co-extruders are generally priced below fluorinated bottles, but their quality is uneven. For example, a manufacturer of a total of squeeze bottles for normal temperature irrigation drop test, there are 4 cracks in 10 bottles. What's more, co-squeezing bottle manufacturers blame each other for not playing with quality and using inferior materials.

When the inner layer material of the co-extruded barrier bottle is nylon, when the polyvinyl alcohol is used is strictly required, otherwise it will not only fail to achieve the barrier effect, but also cause adverse effects of the failure of the pesticide. This point, there is almost no domestic manufacturer of co-extruded bottles can be made clear.

Development trend of blocking plastic bottles

As a mature technology, the fluorinated bottle will focus on the localization of fluorine nitrogen gas and raw materials. The faster and more localized, the more space there is for the cost reduction. However, in any case, the possibility of replacing the PET bottle with a fluorinated bottle is extremely small.

Blend bottles are more likely to reduce costs. It is reported that a research institute in the south is developing a new technology that incorporates an inorganic barrier material into plastics. Samples have been sent to a pesticide factory for trial use. If successful, the cost can be reduced to that of a PET bottle. In addition, a Sino-Korea joint venture is trying to replace some of the new materials that are targeted at PET bottles.

Co-extrusion bottles are in a melee. If all parties can not escape from the vicious circle of relying on mutual slashing prices to rob the market without regard to quality, it will not only fail to survive, but will also worsen the reputation of the “co-extrusion bottle”, making no one dare to use it, resulting in the ultimate defeat of each other and quitting. Rivers and lakes.