The stretch wrapping film is PE stretch wrapping film. The chemical substance it uses is based on high-quality LLDPE formed by heating, extrusion, casting, and other processes and then cooled by a chill roll.
Regarding the thickness of the stretch film:
In what unit is the thickness of the plastic film calculated?
China uses millimeters (mm) as the standard thickness unit for plastic films, but silk (S) is used in actual use. For example, 1 silk = 100mm, and microns can also be used as the thickness unit, 10 microns = 1 silk = 0.01 mm.
However, in foreign countries, due to the different expression habits, different countries like to express the thickness of the stretch film with different units of measurement.
The first is a Mic. The mic is the unit of thickness, 1 wire=10mic=10um=0.01mm, then 1mic=0.001mm.
The second is an μm, a micron is a unit of length, a unit of measurement length in the micron metric system 10μm=10um=0.01mm, then 1mic=0.001mm.
The third type is a Mil. Closely related to this thickness is another unit of measurement, the inch. For example, the American dosage is accustomed to using the imperial system, and the thickness of thinner materials is in inches as the smallest unit, 1mil=0.001inch=0.0254mm≈25mic.
The fourth type is a gauge, which our customers often mention. Through our calculation, 40guge=10mic=0.01mm.
After understanding the conventional thickness expression, let’s take a look at the common thickness of stretch film:
The thickness of stretch film is from 12 to 50 mm, and the market demand for stretch film is increasing yearly. Currently, the annual growth rate of the market demand for stretch film is 5 to 7%, and the demand in the European market in 2004 is very considerable. This is because the stretch film for hand use accounts for 40%, the stretch film for machine use accounts for 48%, and the other stretch film accounts for 12%. Its thickness is generally between 10-50mic. The most common stretch film is currently 20-25mic, which is widely used by European and American customers, while customers in Japan and South Korea prefer thinner stretch films, such as 17mic.
Why is the stretch film thin and not broken?
PE stretch film initially used EVA as the self-adhesive raw material, but it has a high cost and taste. Later, PIBVLDPE was used as the self-adhesive raw material. The substrate is mainly LLDPE, including C4C6C8 and metallocene PE (MPE) metallocene polymer. Vinyl products are a unique class of single resins that offer an unprecedented close combination of film processing and the performance benefits of high carbon alpha olefins (HAOs).
Processing plants can achieve a more stable production process, improve efficiency, reduce film thickness, and simplify the procurement of resin raw materials. MPE resin has a relatively wide processing range on LLDPE and LDPE plastic film production and processing equipment and can cope with changes in production conditions.
Compared with LLDPE/LDPE resin, it can still provide better results. As a multifunctional resin material, MPE resin can create value in multi-layer blown film production lines, cast film production lines, and single-layer blown film production lines and contribute to sustainable development. In the early days, LLDPE stretch films were mostly blown and developed from single-layer to two-layer and three-layer. Currently, LLDPE stretch films are mainly produced by casting method, and due to the narrow molecular weight distribution of stretch films, the production and processing range is also narrow. This is because the production and processing conditions cannot be controlled. Generally, add 5% LDPE to reduce the melt viscosity and improve the flatness of the stretched film.
Casting production has the advantages of uniform thickness and high transparency and can be applied to the requirements of high-rate pre-stretching. However, since single-layer casting cannot achieve single-sided adhesion, the scope of application is limited. Therefore, the structure of multi-layer co-extrusion is ideal. The stretched film produced has a uniform thickness, good tensile strength and is not easy to break.
How to reduce the cost by changing the thickness of the stretch wrapping film?
From 1975 to 2013, the uniform thickness of stretch wrap film once decreased from 30 μm to 20 μm, while the stretch rate increased from 50% to 300%. This is thanks to the development of new materials, such as metallocene materials, which provide higher tensile strength and elongation. How does stretch film reduce its production cost？ Thickness; it is mainly used to reduce its thickness. For example, the original thickness of a roll of ordinary stretch wrapping film is 20mic, and now we have reduced the thickness to 13mic. Under the same length and the same width, the net weight of the stretch film is also greatly reduced. The weight of the stretch film is reduced from 5kg to 3kg. Therefore, the total cost is also lower. Nowadays, there are large and small manufacturers in the market. Many manufacturers have made many quality changes to stretch films to save costs, resulting in many inferior stretch films on the market.
There should be many customers who think that since the length and width of the stretch film remain unchanged, only the thickness has changed so that its own quality is also discounted.
There is no need to worry about this problem. The stretch film researched by our company is based on the principle of constant quality change. The purpose of Sinyar stretch film is to reduce costs for our customers who use our stretch film.
Stretch film has strong toughness, high elasticity, puncture resistance, tear resistance, high viscosity, ultra-thin thickness, cold resistance, heat resistance, pressure resistance, dustproof, waterproof, used for manual stretch film, and can also be used for machines stretch The film has the advantages of single-sided adhesive and double-sided adhesive.
Is the thicker stretch warp film, the better?
Many consumers feel that the thicker and thicker our stretch film is and that the thicker it is, the better its anti-penetration effect is. Any of our items have a fixed range of values.
If we make a particularly thick stretched film today, we will find that it is difficult to stretch during the inspection process, especially in manually stretched films. Another is the reduction of its viscosity, which greatly affects our Effect.
Today, the thickness of the manual stretch film on the market is 0.02 mm, thinner than the 0.025 mm of the motorized stretch film. That’s because, in the case of manual force, the degree of packaging is not as good as that of mechanical movement. This design can put the two at the same level.
Therefore, the stretched film does not mean that the thicker it reflects, the better the effect.
Currently, one of Sinyar’s bases is vigorously producing a nano-stretching film. Nano stretch film is a high-end film. Therefore, reduce the net weight of the product, reduce the production cost, and provide customers with a better solution.
What factors affect the uneven thickness of the stretch wrapping film?
When we buy stretch film, there will be some uneven thickness. The stretch film is stretched manually or mechanically under normal temperature conditions, resulting in changes in its properties. It can be well used to package commodity goods, which is more convenient for us to transport. When the stretch film is used for packaging, its tear resistance and penetration ability are excellent. Suppose the thickness of the stretched film is very uneven. In that case, it may be that the unreasonable heating temperature setting during the production process leads to the uneven thickness of the stretched film. Because the temperature directly affects the flow of the melt in the runner, which is related to the longitudinal thickness distribution of the product, it is necessary to check whether the heating device and the thermostat are damaged in this case and whether the temperature of the heating zone is reasonable to ensure that the heating temperature is stable.
So what factors affect the uneven thickness of stretch wrapping film?
- The stretch film produced under the blow molding process has uneven distribution due to the high and low die temperatures, so the thickness of the stretch film after blow molding is uneven. The die temperature of the machine head can be adjusted to make the mold. The temperature of the mouth is uniform.
- The gap between the die openings is not uniform, some parts have larger gaps, and some have smaller gaps, resulting in more or less extrusion, resulting in an inconsistent thickness of the stretched film produced. Some parts are thin, and some At this time, we only need to adjust the die gap of the machine head to ensure uniformity everywhere.
- The inflation and traction ratios are not suitable, making the film bubble’s thickness difficult to control. However, the inflation and traction ratios can be adjusted to make the thickness of the produced wrapping film uniform.
- The air supply around the cooling air ring is inconsistent, resulting in an uneven cooling effect and thickness of the stretched film. At this time, it is necessary to adjust the cooling device to ensure uniform air output from the air outlet.
- If the traction speed is not constant and changes continuously, it will also lead to uneven thickness of the produced Yunnan stretch wrapping film. At this time, check the mechanical transmission device to keep the traction speed constant.
Some cavity gaps are uneven, some parts have large gaps, and some have small gaps, resulting in more or less extrusion. Therefore, the thickness of the stretched film is inconsistent. Some are thin; some are thick. We only need to adjust the gap between the die holes to make all parts uniform. The reasons for the uneven thickness of the wrapping film are mainly the above points.
However, suppliers with good production quality can control the uneven thickness within a reasonable range. However, due to today’s technical problems, uneven thickness is a common problem that cannot be eliminated. This is a technical barrier that we cannot break through at present. This situation will not affect the use of stretch wrap film. However, the uneven distribution of thickness will be reflected in the technical data sheet.
Similar techniques are often used in stacks in the case of stretch films that are not very thick. Its stacking technology refers to the use of metal composite materials placed on top of the previously used technology is called surface stacking. And “thin” as an objective stage, for this technology, the stacking thickness can be controlled to between several to tens of nanometers to obtain a new stage technology.
