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March 7, 2024

Understanding the Difference Between Co-Extruded and Monolayer Greenhouse Film


Arpit Kushawaha


greenhouse plastic film


Multi-layer co-extrusion barrier film denotes a useful composite film created by utilizing various extruders to extrude the melts of resins with increased barrier features and other resins through a usual die. In the area of plastic items, we normally refer to flat plastic derivatives with a width of less than 0.2 mm as plastic films, those with a density of 0.2 to 0.7 mm as plastic sheets, and those with a breadth greater than 0.7 mm as plastic sheets. 

Plastic film for greenhouses has many properties that make it beneficial as a cover for greenhouses.  Its low expenses, large sheet size, ease of attachment, and good light diffusion are features that have helped to enlarge its usage so that today it is the most usual glazing. Since the early 1960s when polyethylene film was first utilized to cover wood frame greenhouses, many developments have been made.  Durability was missing in earlier Greenhouse Plastic Films and had to be exchanged annually.  They didn’t stand up to the scrape from the construction and the climate.  They also had a short life due to the worsening from the ultraviolet rays of the sun.

The multi-layer co-extruded barrier film should have definite gas barrier features. The barrier materials here designate the shielding ability of plastic items (containers, films) to small molecular gases and smells. We typically utilize gas penetrability to measure the size of the barrier properties of plastic products.

So what are the mechanical aspects of the multi-layer co-extruded film constructed by dividing the obstruction layer and the heat-sealing coating through the functional division of more coatings? The subsequent takings of 7-layer co-extruded film as a sample to equate with 5-layer co-extruded film:


Cost Comparison

Swapping costly polymers with inexpensive polymers on the surface coating can decrease the price of the item, and has the heat-sealing features and high dampness barrier aspects of ionic polymers. With the same obstacle properties and heat-sealability, 7-layer co-extruded blown film is cheaper than 5-layer. The two exterior layers are separated into two groups, and one group is created of cheap fabrics, which not only upholds the power of the film but also saves costs. 


Utilizing two various polymers to swap a single kind of polymer on the obstacle coating can significantly enhance its barrier features. For example, uniting an EVOH coating with a characteristic nylon fabric not only retains the diffusion confrontation of the PA but also increases the power of the EVOH and enhances the crack confrontation of the EVOH because the EVOH layer is crammed between two coatings of PA amine. , manufacture it as a film with high barrier properties, which cannot be proficient by 5-layer co-extruded films.

Crack resistance

The performance of PA co-extruded films with less than five coatings can be enhanced by utilizing co-extruded films with more coating. For example, the use of an extra adhesive layer can improve the barrier features of the film by aggregating the water vapor barrier of the film. 

However, the systematic usage of raw materials, the strategy of reasonable item structure, and the close coordination with the processing technology are never-ending tasks facing each of our composite film manufacturers. Only when the technical properties of processing tools, processing raw fabrics, and structural design (processing technology) are fully used and reach the best state, can the packaging substrate be utilized in the most economical, reasonable, and sufficient way in its final item. , the cheapest form, and meet the requirements of the market.

Most Greenhouse Plastic Film is created as a co-extrusion of three coatings with different polymers and additives.  Each of them donates to the quality of the film and improves its performance.  The following sums up some of the features that you require for your crops.

Life – the life of polyethylene films is insufficient due to the dilapidation process caused by sunlight and heat. Co-poly is a low-cost fabric that is good for one season.  It is a decent choice for seasonal greenhouses, overwintering layouts, and high tunnels.  Evade construction-grade material that has less power. Greenhouse-grade poly is assured for 4 years or more and costs about double that of co-poly.  It comprises an ultra-violet (UV) additive that decreases degradation.  If extra strength is required, such as blustery in locations, a woven poly or nylon scrim-reinforced fabric should be measured.

Thickness – one-year plastic film for the greenhouse is available in 3, 4, and 6 mil thicknesses.  Three or four million films are usual for one year of use on slender tunnels and overwintering houses. Greenhouse grade fabric, only available in 6 mil thickness, is suitable for multi-year application.

Condensate control (AC) – also referred to as anti-drip is a dampening agent that decreases surface tension enabling condensation to stream somewhat rather than form droplets.  This can be scattered on the film or combined in the center layer and normally lasts a couple of years.  Condensation droplets lower light scattering and can lead to illness problems when they trickle onto plants.

Ultra-violet (UV) – bees need UV to traverse. If you are utilizing bees to fertilize plants in the greenhouse, buying a plastic film for a greenhouse that lets some of the UV part of the light energy spectrum permit through may be vital. Otherwise, UV-blocking film will decline whiteflies, thrips, aphids, and other insects.  It can also regulate some fungous infections.

Controlled diffusion – light dispersal is another property that has recently been added by greenhouse plastic film manufacturers.  This surges the amount of diffused light that reaches the plants, dipping scorching, and increasing light to lower leaves.  It is particularly vital with tall crops such as tomatoes, cucumbers, and peppers. Research has shown that dispersed light also reduces fungus spore expansion and insect spread.

Plastic failure – early failure of poly can be accredited to attachment stress, scrape on rough shells, and sharp edges or heat buildup in the area of rafters, purlins, and extrusions.  Contact with chemicals from insecticides or pressure-treated lumber can also distress the life of the plastic. Poly may also be subject to cuts from gusting ice especially if there are multiple greenhouses adjacent to each other. A scrim-reinforced poly may be needed in these circumstances.


Frequently Asked Questions (FAQs)

What does greenhouse film do?
Better temperature management – The Clear, white, or green greenhouse films are perfect for keeping the temperature inside the greenhouse. With improved heat retention features, the films can keep the plants active.

What is the best greenhouse film?
In this case, polyethylene is the most extensively utilized kind in greenhouses around the world because of its modest price and excellent mechanical features. In addition, it is very comfortable to incorporate additives to enhance its features.

How do I choose a greenhouse film?
The films should be selected as such it is capable of delivering the maximum quantity of diffused light. In addition to this, choosing greenhouse films that propose very little diffusion of light enhances the chances of burning and at the same time can cause the greenhouse to overheat.



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