» GREENHOUSE FILMS

LONG LIFETIME

Greenhouse films contain special combinations of UV-stabilisers and antioxidants protecting them from the harmful effects of UV light and heat for very long periods. All formulations are based on HiTeC's own know-how and experience. Additive concentrates are manufactured inhouse to ensure absolute consistency in quality.

Film lifetime is guaranteed for a period of 1-5 seasons (depending on type of film and area of use). In most cases, greenhouse films contain more and more efficient UV-stabilisers than films of other producers, which is one of the reasons why PEP films usually last longer than they are prescribed for.

Due to the increasing use of sulphur and other chemicals in the greenhouses, that neutralize traditional UV-stabilizers and may lead to premature failure of the film, HiTeC has developed fully chemical resistant formulations that can be incorporated upon demand in any of its greenhouse film types for additional safety.

TOUGHNESS

HiTeC's experience in processing conditions and quality control procedures as well as the careful selection of raw materials, ensure that its greenhouse films have excellent mechanical properties. A new generation of super-tough films has been introduced by using special high-strength polymers. These films offer additional safety in areas with very strong winds, or significant economy as they can be produced at a lower thickness than regular films, while maintaining the same or higher strength.

THERMIC EFFECT

HiTeC offers special 3-layer thermic films, containing a combination of EVA and Infra-Red additives skilfully structured in the 3 layers, which absorb the Infra-Red radiation and reduce heat losses throughout the night.

The advantages of thermic films are:

• Protection from frost and low temperature.
• Smoother temperature drop.
• Overall higher night temperatures.
• Reduced energy consumption for heating.
• Higher crop yield.
• Earlier harvesting.
• Better quality of crops.

COOLING EFFECT

In many areas of the world there is growing requirement for films that reduce excessive heat during the day time and help to maintain a cooler environment in the greenhouse. Particularly in the "tropics", in areas with strong sunlight and hot weather as well as well as in nurseries, or in cases of shade-loving plants, “cooling films” are gradually becoming a necessity. HiTeC's product range offers special film types which reflect and /or absorb Near Infra Red (NIR) radiation, the part of the solar spectrum carrying most of the heat entering a greenhouse. NIR radiation is not essential to plant growth and by preventing it from entering the greenhouse, “cooling films” achieve significant reduction of heat inside the greenhouse during the day time. Usage of such films has demonstrated that the higher the ambient temperatures of the area are, the larger is the heat reduction achieved.

LIGHT TRANSMISSION

High light transmission is absolutely essential to plant growth. Experience in production, quality of equipment and selection of materials, ensure that HiTeC 's films have the maximum light transmission.

LIGHT DIFFUSION

Sun light passing through a greenhouse film and entering a greenhouse is spilt into “direct” and “diffused”. Even though increased levels of diffusion can cause a film to appear “hazy”, they do not affect the total quantity of light that is passing through the film. The total amount of PAR (Photosynthetic Active Radiation) received by the plants remains the same.

It is now generally accepted that diffused light has a positive effect on plant growth, especially for spring and summer crops and in areas with many days of strong, direct sunlight during the year. Light diffusion offers a moderate cooling effect, it prevents burnings, it reduces shadows and ensures more uniform distribution of light, so that it reaches even the lower parts of plants.

HiTec has the know-how and therefore the ability to produce:

• Crystal clear films with very low diffusion
  (Maximum direct light).
• Films with medium diffusion
• Films with very high diffusion

The choice of the most appropriate level of diffusion depends on the climate of the area, the crop and the season(s) of growing. HiTeC's experts are at the disposal of our customers to consult them on the most suitable level for every particular case.

ANTI-DRIPPING EFFECT

Droplets formed on the inside surface of greenhouse films due to water-condensation can have negative consequences on plant quality and growth, as they reduce light-transmission by 15-30% and increase the incidence of certain diseases.

HiTeC manufactures “anti-dripping” films that contain special additives which eliminate individual droplets, turning them instead into a continuous thin layer of water that runs down the sides of the greenhouse roof and walls.

Anti-dripping films, when used properly, offer the following benefits:

• More light in the greenhouse
• Higher crop yield
• Earlier harvesting
• Better quality of crop, higher commercial value
• Fewer diseases
• Reduced need for pesticides

Important note: Anti-dripping films are mainly recommended for well ventilated and/or heated greenhouses, with adequate inclination of the roof. The "anti-dripping" effect lasts for up to 2 years, due to the fact that additives function by physically migrating to the surface of the film and are gradually washed away by water. Under certain circumstances there is mist (fog) formation in greenhouses covered with anti-dripping films. Such mist usually occurs at sun-set and dawn and is undesirable as it could cause damages to the plants. It is strongly advisable to ventilate and/or heat the greenhouse immediately, to remove this mist. Due to the complex mechanism of its activity and to the variety of parameters affecting its function, HiTeC does not provide a warranty nor assumes any liability on the effectiveness and duration of the anti-dripping effect.

ANTI-FOGGING EFFECT

HiTeC has developed anti-dripping films with a special antifog function that inhibits or reduces the formation of fog that sometimes occurs during early morning and/or after sunset in greenhouses covered with anti-dripping films. This makes it possible to take advantage of the benefits of antidripping films without the problems associated with fog.

Note: Due to the complex mechanism of its activity and to the variety of parameters affecting its performance, HiTeC does not provide a warranty nor assumes any liability on the effectiveness and duration of the anti-mist effect.

DISEASE CONTROL EFFECT

HiTeC has developed a range of special disease control films that contribute to “Integrated Pest Management” and therefore assist in reducing the usage of pesticides.

Important types of disease and insect control films are UVblocking films, that absorb UV-radiation up to 380nm, thus achieving:

• Reduction of the population of whiteflies, thrips, miners, aphids and other harmful insects.Reduction of such populations also results to reduction of viruses which can be vectored to cultivars by these insects.
• Control of the spread of certain diseases, by reduction of the sporulation of the relevant pathogenic fungi.(Example: Botrytis)
• Reduction of "petal blackening" of red roses, which actually results in increasing their commercial value.

Note: “UV-blocking” films should be used after testing when a) bumble-bees are used as pollinators b) when beneficial insects are used for pest control and c) when growing eggplants or other purple flowers or crops. A number of other parameters, such as temperature and humidity, enhance the development of diseases. The plastic film alone may not control diseases, it can, however, contribute to their control, when used in conjunction with other suitable methods.

PHOTOSELECTIVE EFFECTS

HiTeC offers a range of special films incorporating selected additives and pigments to modify the light spectrum entering the greenhouse, thus changing the growth behaviour of plants (photosynthesis and photomorphogenesis). By using such films it is possible to increase the yield, to promote or retard the growth and to cause elongation or dwarfing of the stems.