Toughness, visibility, durability, safety, temperature and recycled resistance, this is asked of an agricultural crate

In the countryside, when there is a period of fruit and vegetable harvesting, which still takes place mainly by hand, the containers of agricultural products collected, to be transported to the processing and packaging departments, must have special characteristics.

The agricultural casings,called transport because they have the function of receiving the fruit or vegetables removed from the plant or field, are generally plastic elements suitable to contain the product and then transported to processing and packaging centers.

In the past all transporting agricultural crates were produced using virgin polymers,and made using bright colors such as yellow, red, white to be easily noticeable in the field.

This type of packaging is also used for the containment and shipping of high-weight processed fruit, which must also receive storage at low temperatures.

Today the agricultural case is generally produced in recycled material, whether in PP or HDPE,using materials from the separate collection. An attempt was made to give a regulation to the product supply chain that required the use of recycled materials from agricultural coffers alone, but in fact traceability, in the processing phases of plastics through the collection, grinding, washing and possible granulation, does not allow possible contact with other types of plastics or contamination.

This is because, although they have packaging from agriculture alone, the processes of processing and recycling in a new raw material,subject the input to the passage into shredding machines and washing and extrusion plants, in the case of granules, which have also worked other raw materials.

On the basis of this information, however, it must be said that the product collected in the field already has in itself a degree of protection that can be the peel,also, among other things, subjected spraying insecticides and antifungals during the growth phase of the product, which have a much more important impact than contact between fruit and an inert product such as recycled plastic.

The choice of plastic to use depends on the work cycle of the food that will be contained and the type of logistics that you have to use.

If the case has a mere function of the mobility of the crop from the field to the processing plant, it is not very important to choose whether to use a polypropylene case or high-density polyethylene case, but if the fruit or vegetables are to be stored in cold storage, the choice falls on HDPE which has a degree of resistance to low temperatures more important than polypropylene.

The production of the raw material, of both plastic categories, takes place through the use of the waste of the packaging that the recycling system can make available and through the conversion to new warehouses of beverage or logistics companies, which periodically replace their container fleet.

Let’s look at the differences in the production of the raw material:

• Polypropylene it is generally produced by food packaging waste, agricultural and industrial boxes that are selected by provenance, ground in sizes of about 10-12 mm., deferred, washed in rotating and decanting plants in the tank, densified by packaging gaps and, if required, initiated to extruders for granulation. The fluidity of the product made normally hovers around a range between 6 and 12 to 230-2.16 kg. and can be generally colored with dark colors. The raw material enjoys a certain abundance in plastic markets and generally has a low price for both mince and grain. The cases are robust, as normally the percentage of PP within the recipe is usually around 90, but are not recommended for use in cold storage.

• High-density polyethylene does not enjoy the same ease of finding on the market as the packaging industry, especially the mineral water and soft drinks industry, has long focused on plastic film packaging, leaving the recycling market without a product.There are still production areas in the world where we prefer to make crates with virgin materials, especially in some food sectors where there is direct contact with unprotected food, and this generates a small recycling market. Other production of crates with virgin raw material are carried out in countries where material separation systems and subsequent recycling are not so developed as to create a sufficient supply cycle for those who build these packaging. In any case, the production of a recycled HDPE for the production of agricultural crates goes from the separation by color of the available crates, so that you can use the raw material without adding dyes during molding, grinding and deferring the grind in HDPE and the subsequent washing with double passage as for polypropylene. The fluidity ranges from 6 to 8 to 190 degrees/2.16 kg, and the grind can be used directly in the machine to produce the case or move on to the granulation phase.

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