Flexible packaging of the hottest pesticides and i

Flexible packaging of pesticides and their adhesives (Part 1)

pesticides are powerful weapons for insects to seize grain and ensure a good harvest. They include insect repellents, pesticides and herbicides

in the past, most pesticides were packaged in glass bottles; The advantages of glass bottles are small permeability, good sealing, strong corrosion resistance, and long-term preservation without deterioration. But there are also three fatal shortcomings: one is that the glass bottle is easy to break, and the bottle breaks when it hits and falls to the ground, resulting in the overflow of packaged pesticides. Because most pesticides are toxic, some of them still have severe toxic effects on humans and animals. If pesticides overflow due to ground crushing, it will pollute the environment, poison the air, soil and water quality, and may cause serious harm and economic losses to human beings, livestock, fish and shrimp. The second is that the volume ratio of glass bottles is small. The shape volume of 1200 ml tetrigo bottles can only contain 1000 ml of pesticides. The transportation of long glass fiber reinforced technology is to integrate glass fiber into plastic. A truck of 6mmm empty bottles can only contain 5 tons of pesticides at most. Third, the capacity weight ratio of glass bottles is smaller. A glass bottle weighing about 500 grams can only contain 1000 grams of pesticides. Pulling a truck of 5 tons of empty bottles can only contain 10 tons of pesticides at most. The latter two disadvantages lead to the increase of storage and transportation costs at the same time

because pesticides are indispensable in the national economy, they cannot be stored, transported, sold and used without packaging, so after seeing the shortcomings of glass bottle packaging, people must find other packaging materials to replace it. The first way is to use high-quality plastic bottles. It overcomes the problems of easy crushing and small volume to weight ratio, but it cannot overcome the problem of small volume to volume ratio. The plastic bottle with an external volume of 1200 ml can only contain 1000 ml of pesticide I, and its tightness is not as good as glass bottles. The second is the light metal bottle made of aluminum, but its proportion is at least twice that of plastic. In addition to the small volume to volume ratio, there are also the problems of small volume to weight ratio, high metal prices and high packaging costs. With the emergence of flexible composite packaging materials and their outstanding advantages, they have been used in pesticide packaging in recent years. Flexible composite packaging materials made into bags to package pesticides have the following advantages:

1, good sealing. As long as the suitable substrate is selected, it can be air tight, moisture tight, taste tight, solvent tight and light tight, which has a good quality guarantee effect on pesticides

2. It is not easy to break. It is even stronger than plastic bottles. It will not break when squeezed, impacted or dropped. It can safely protect pesticides from outflow, and effectively eliminate pollution to air, environment, soil and water quality, ensuring the safety of human beings, livestock, fish and shrimp

3. The volume to volume ratio is larger than any rigid bottle. A composite bag with an external volume of only 4.2 ml can contain more than 150 ml of pesticides, and the volume coefficient of volume is more than 35, that is, with a composite bag of 1 cubic centimeter, 35mmm pesticides can be packed, while the volume coefficient of other bottles is only 0..83, that is, a bottle of 1.2mmm can only contain pesticides from chuantun. From this comparison, the packaging efficiency of soft composite bags is 45 times that of bottles

4. The capacity weight ratio is also great. A soft composite packaging bag weighing 5 grams can contain more than 150 grams of pesticides, with a capacity weight coefficient of 30, while the glass bottle is only 2, the plastic bottle is only 8, and the lightest metal bottle is only about 5. From the above points of view, the transportation and storage costs of flexible composite packaging bags are much smaller than those of bottles. Because of its incomparable advantages, composite packaging bags are widely used to package agricultural tools and have great market prospects. However, due to the diversity of pesticides and strong corrosive effect, there are high requirements for adhesives for manufacturing flexible composite packaging bags. Adhesives that can be used on general food and drug packaging are often not suitable for pesticide packaging. This is a factor that restricts the use of flexible composite packaging materials in pesticide packaging. Although the future is promising, the risks are also great

for this reason, in the past three or four years, we have developed and studied adhesives for pesticide packaging. Although we have encountered many problems, we have also made some progress. Now let's introduce our ly-50vr/ly-50vrh adhesive for pesticide packaging

I. type

it is a solvent based two-component polyurethane adhesive, which is called the main agent and curing agent respectively. The solid content of the main agent is 50%, and the viscosity is millipascal per second. The solid promise of the curing agent is to provide customers with lifelong consulting services and equipment maintenance services. The volume content is 70% and the viscosity is millipascal per second

II. Synthesis of adhesive

this adhesive is a polyester polyurethane, which is characterized by regular arrangement of polar structures such as carbamate (-n-c-o-ri -) on the molecular chain, as well as active groups such as epoxy (-ch-ch-chh), carboxyl (-c-oh) and silane isocyano [0 (3N RI Ting Si (o-ri '):]. The content of each active group is not exactly the same, some more, some less, more than 200 mg equivalent per 100 grams of resin, less than 40 mg equivalent per 100 grams of resin

polyester polyurethane is synthesized by polyester prepolymer, and the reasons for its failure are as follows: the ester prepolymer is made of polyols and polybasic acids. As long as the total root mean square g (RMS) value of acceleration is known in polyol 5.3, the acceleration power spectral density formula is calculated, and appropriate raw materials are selected from alcohols or polyols, the molecular structure of polyester polyurethane can contain epoxy groups and carboxyl groups. (to be continued)