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Plastics for Greenhouses

plasticos-invernaderosAPR

One of the main characteristics of greenhouses is the use of plastic as a enclosure material, except for the Venlo-type or Dutch greenhouses which use glass.

In the market there are different plastic materials for greenhouses, and depending on several factors we would choose one or the other. An example of plastic widely used in greenhouses is 3 years thermal plastic, which has the following characteristics:

Blade made of three-layer LDPE (coextrusion) white translucent:

  • Outer Layer: durable and non-stick, has additives against UV radiation
  • Middle Layer: Thermal, high EVA content, providing thermicity.
  • Inner layer: provides light diffusion and has co-stabilizers resistant to pesticides

Main types of Plastics for Greenhouses:

POLYETHYLENE (PE)

Polyethylene (PE) is the simplest polymer chemically. It is one of the most common plastics due to their low cost and simplicity of manufacture. As the polymerization conditions (temperature, pressure, catalyst) can be obtained:

  • PEBD: conventional low density PE, which is used in greenhouse covers
  • PELBD: lineal low density PE, for padded and small tunnels.
  • PEAD: high density PE containers and used in irrigation and drainage. .

Vinylacetate ethylene copolymer (EVA)

The EVA films are widely used for covers, double covers (as heat shield) and in the protection of low tunnels. EVA has a better mechanical resistance than PVC, depending on the concentration of vinyl acetate.

Polyvinylchloride Vynil (PVC).

PVC is a rigid plastic which plasticizers are added to make it more flexible for using as plastic film in greenhouse covers. It is sensitive to cold, the dust container and also has the disadvantage of color over time.

POLYCARBONATE (PC)

In the greenhouse is used in side or front walls, this material is being used exclusively or in parts of the enclosure such as the frontal area that determines the arc.

Characteristics of the different types of plastics for greenhouses:

 
 Transp. Light (%)
 Transp. IR (%)
 Transm. Hot (W/m2ºC)
Density (g/cm3)
Anti-drip
Anti-dust
PEBD 
 90  62-65  8-9 0,91-0,93 NO YES
 PEAD
 90  62-65  8-9 0,96 NO YES
 EVA
 90  11  6-7 0,92-0,93 NO NO
PVC
90 20-30 7-8 1,16-1,5 YES NO
PC
75-83 0 4-4,8 1,2 YES YES