Safety nets are protective nets installed under or on the side of high-altitude building construction equipment installation or technical performance to prevent accidents caused by falling people or objects. The safety net consists of a net body, side ropes, tethers and tendons. The mesh body is braided with net rope and has diamond or square mesh. Mesh size refers to the distance between two knots adjacent to the knit. The net ropes on the edges around the net body are called side ropes. The size of the safety net (nominal size) is determined by the size of the side rope; the rope that secures the safety net to the support is called a tether. In addition, any rope used to increase the strength of a safety net is collectively referred to as a tendon.
The safety net consists of a net body, side ropes, tethers and tendons. The mesh body is braided with net rope and has diamond or square mesh. The distance between two adjacent knots of a knit is called the mesh size; the net ropes on the edges around the net body are called side ropes. The size (nominal size) of the safety net is determined by the size of the side rope; the rope that secures the safety net to the support is called a tether. In addition, any rope used to increase the strength of a safety net is collectively referred to as a tendon. The safety net material requires small specific gravity, high strength, good abrasion resistance, large elongation and strong durability. In addition, it should have a certain weather resistance, and its strength does not decrease too much after being wet and wet. Safety nets use chemical fibers as the main material. All net ropes on the same safety net must use the same material, and the wet-dry strength ratio of all materials must not be less than 75%. Generally, synthetic chemical fibers such as vinylon and nylon are mostly used as net ropes. Polypropylene is forbidden due to its unstable performance. In addition, as long as it meets the requirements of relevant international regulations, cotton, linen, palm and other plant materials can also be used as raw materials. No matter what material is used, the weight of each safety flat net should generally not exceed 15kg, and it must be able to withstand 800N impact.
Building Safety Mesh,Construction Safety Net,Architectural Safety Net,Architectural Protection Net Jieyang Xinxin Industry and Trade Co., Ltd. , https://www.gdxxgm.com
10 aspects to consider when purchasing white masterbatch
There are 10 aspects to consider when purchasing white masterbatch :
1, whiteness
The whiteness of the white masterbatch is mainly represented by the titanium dioxide in the color masterbatch, and there are many factors affecting the whiteness of the titanium dioxide, including the size, shape and particle size distribution of the titanium dioxide particles, the type and content of the impurities, and the lattice of the titanium dioxide particles. Defects. In general, the chlorination method titanium white powder whiteness is better than the sulfuric acid method because the purity of the raw material titanium dioxide is high and the impurities are small during the preparation process. In the real white mother market, many white masterbatch producers pretend to be titanium dioxide by adding equal ash content of calcium carbonate, barium sulfate and zinc sulfide. In fact, the whiteness of these inorganic powders is incomparable with titanium dioxide. .
2, hiding power
The hiding power is also an important indicator of white masterbatch. The good hiding power means that the pigment has strong tinting strength, and the desired effect can be obtained with a small addition amount. The hiding power of the white masterbatch depends on the choice of titanium dioxide. Compared with the processing technology, rutile titanium dioxide has an smaller and tighter unit lattice and a larger refractive index than the anatase titanium dioxide, so the hiding power and ultraviolet light resistance are obviously superior to anatase. For the same type of rutile titanium dioxide white masterbatch, the titanium dioxide has a small particle size and a narrow particle size distribution. The opacity of the dispersion in the masterbatch is significantly wider than that of the titanium dioxide, and the dispersion is poor in the masterbatch. it is good. Similarly, the opacity of common calcium carbonate, barium sulfate, and zinc sulfide is also incomparable with titanium dioxide.
3, moisture content
The moisture content in the white masterbatch also plays an important role in the performance of the masterbatch. Generally, the moisture content should be controlled below 1500ppm, and the strict requirement should be below 600ppm. In the injection molding process, the raw materials are generally dried before production. In the film production, the customer buys it directly after premixing with the carrier. If the moisture content of the masterbatch is high, it will directly lead to membrane rupture, and some small bubbles will form on the film, "crystal point". Such defects, and the reason for the high moisture content of the white masterbatch, have an influence on the raw materials selected from the masterbatch to the process.
4, dispersion
Dispersibility has an important influence on the application of titanium dioxide in plastics. Generally, the finer the titanium dioxide particles, the better the dispersion, the higher the color strength, and the white mother with excellent dispersibility when the film needs fine printing. The grain pattern clarity, layering, and vividness are better because the microscopic smoothness of the base film is one of the determinants of the quality of the printed pattern.
5, smell
Some film manufacturers will smell a strange smell after using the white masterbatch, which is absolutely not allowed in the milk film and the film in contact with food. This is mainly because the titanium dioxide in the masterbatch is organic. During the treatment, the coating aids selected are not suitable or the addition amount is too large, or the dispersant selected in the production process of the master batch is problematic, and the white masterbatch grade can be replaced.
6, hue selection
Rutile titanium dioxide has a low reflectance in the violet region, so the rutile titanium dioxide has a "yellowish" hue, and the "yellowish" hue gives the colored product a "sand" feel and makes the fine printed image bright. Degree and layering are degraded, which is unpopular among many white masterbatch users. However, after adding a small amount of fluorescent whitening agent to titanium dioxide, it can absorb ultraviolet light with a wavelength of 300-400 nm and convert it into a wavelength of 400. -500nm blue fluorescence, so that the white masterbatch can be "blue phase", white masterbatch users are considering according to their own needs.
7. Liquidity
The fluidity of the white masterbatch can be expressed as the melt index (MI), the value is low, the flow is good, the flow is good, the machineability is low, the power consumption is low, and the user chooses the white masterbatch. In addition to the good fluidity of the masterbatch, it is also necessary to note that the masterbatch is suitable for the carrier resin in the factory product. The general principle is that the MI of the masterbatch is higher than that of the carrier resin.
8, printing heat sealing performance
White film products require printing and heat sealing in most cases. If the addition of calcium carbonate in the white masterbatch affects the sharpness and vividness of the printed pattern, the incorrect or excessive dispersing agent added to the masterbatch will also affect the heat sealing and Printing performance.
9, light fastness and weather resistance
White masterbatch generally requires 7-8 grades of light fastness, 4-5 of weather resistance, and 280 degrees of temperature resistance. These requirements mainly depend on the quality of titanium dioxide. To achieve the above conditions, it must be rutile titanium dioxide. .
10. RoHS & FDA
Heavy metal testing and food contact permits are also an important indicator of white masterbatch, as many white films are used in food packaging and are subject to FDA food certification.