As we all know, the sun's radiation can be divided into three parts: ultraviolet, visible light, and infrared.
The ultraviolet rays are radiation containing a large amount of energy, but part of the ultraviolet rays are absorbed by the ozone layer.
So, what is the purpose of using agricultural film? How to buy agricultural film? How to distinguish quality? Let’s find out together below.
The purpose of using agricultural film: As mentioned above, simple PE cannot absorb long-wave FIR-far infrared rays, so it has no thermal insulation effect.
To achieve the thermal insulation effect, stone powder (CaCO3) additive or EVA must be added to absorb far-infrared rays with wavelengths exceeding 3,000nm.
CaCO3 has a very good thermal insulation function (the thermal insulation effect is achieved by reducing the far-infrared transmittance. Generally, if its penetration rate is lower than 20, it is considered to have the thermal insulation effect). It is a very good The interesting phenomenon is that in the cold winter, when the sky is clear, the FIR disappears very quickly at night (that is, the temperature drops sharply).
Although adding CACO3 to the formula can achieve the effect of heat preservation, it will also reduce the light transmittance of the film.
Another option is to add some ratio of EVA to the pure PE formula. The higher the ratio, the better the thermal insulation effect, and it will not affect the original light transmittance.
However, in a single-layer blow molding machine, the ratio of EVA cannot be increased arbitrarily because defects will occur. This is why a three-layer *** extrusion blow molding machine is used; generally The method is to use a high-content EVA in the middle layer with an outer layer with less EVA content. This can greatly increase the total content ratio of EVA, which can effectively improve the thermal insulation effect of the product and avoid product quality problems.
(That is, the lower the disappearance rate of far-infrared rays, the better the insulation effect) How to buy agricultural film: As the saying goes, there is no good product if it is cheap. When buying agricultural film, you should not just buy it for a short time. In addition to this Click to buy agricultural film and choose agricultural film, and I will teach you a few tricks. You will remember four words: look, touch, pull, and check.
The so-called inspection is to see whether the appearance of the agricultural film is smooth, whether there are stains, whether there are cracks, and whether the transparency is good.
If the appearance is smooth and transparent, the quality will generally be good, and vice versa.
The second is touching.
The so-called touching means holding the agricultural film in your hand and pinching it to see if it is soft and whether it feels elastic.
Let’s feel the thickness of the agricultural film again. Agricultural film that is soft, elastic and has a relatively thick texture is generally a good quality agricultural film. If not, we will not believe it.
The third is pulling.
That is, try to take the agricultural film in your hand and pull it. The longer you pull, the better the toughness. Generally speaking, cut off a piece of agricultural film that is about as long as a cigarette. If you can pull it to the length of five cigarettes, it means that the quality of the agricultural film is good. You can also have multiple people pull it from four aspects to test the toughness.
The fourth is to check.
That is to check whether the manufacturer is standardized, whether the production process and equipment technology are excellent, whether the packaging meets national requirements, whether the factory address, telephone number, trademark and other information are complete, and more importantly, the after-sales service is good.
How to distinguish the quality of agricultural film: 1. High-transmittance agricultural film has good transparency, while ordinary agricultural film is white and foggy; 2. High-quality agricultural film has good weather resistance, and in