Excel Industrial and Agricultural Textiles and Shade Systems and Nets EXCEL INDUSTRIAL AND AGRICULTYURAL TEXTILES AND SHADE SYSTEMS AND NETS Information about Excel textiles/shade systems/net: SEVERAL CHARACTERISTICS DISTINGUISH POLYETHYLENE AND POLYPROPYLENE GENERAL PROPERTIES OF POLYPROPYLENE MONONFILAMENT DOUBLE LAYER SHADE SEVERAL CHARACTERISTICS DISTINGUISH POLYETHYLENE AND POLYPROPYLENE Polyethylene Polypropylene Low specific gravity Low specific gravity Resists mildew and insects Resists mildew and insects Same tensile strength, wet or dry Stronger of the two Melting point: 230-250°F Melting point: 325-340°F Must be pigmented before spinning Can be dyed Can be heat-sealed Doesn’t heat-seal well More elastic of the two More resilient of the two Low moisture regain under stress Will not become fibrous Q: What are the performance characteristics of polypropylene and polyethylene and how do they compare? A: In order to understand the difference between polypropylene and polyethylene, we need to take a look at their origins. Both of these fibers are referred to as olefin, which can be any member of a class of unsaturated hydrocarbons, characteristically exhibiting a good deal of chemical activity. In addition, these chemicals form oily liquids when combined with other substances. This characteristic is what gives them the name olefin, which means oil forming. Ethylene is a colorless flammable gas derived from natural gas and petroleum. It is the base substance for polyethylene fiber, which is manufactured from polymerized ethylene resin in monofilament form. Propylene is also a flammable gas and is derived from petroleum hydrocarbon cracking. It is the polymers and copolymers that form polypropylene fiber. Also helpful is an understanding of the term polymer. These heavy molecular chain-like structures are the building blocks with which all kinds of substances are linked to form fibers and other plastics such as resins and films. When something is polymerized, it is formed into this special structure. Polymers are produced by joining two or more monomers. In this case, ethylene is the monomer of polyethylene and propylene is the monomer of polypropylene. Polyethylene fibers have low moisture regain and low specific gravity. They are very resistance to mildew and insect attach, and exhibit the same tensile strength under wet or dry conditions. if coloring is required, it must be added before spinning, because the-fiber does not dye. Polyethylene has a relatively low melting point and can be heat-sealed successfully. It is also more elastic compared to polypropylene. Like polyethylene, polypropylene has a low specific gravity and is not easily damaged by mildew and insects. That is where the similarities end. Polypropylene fibers are stronger than polyethylene, more resilient, and will not become fibrous under stress, as polyethylene will. It has some advantages over other fibers in the weaving process when coverage is important, because it provides more coverage per pound. Compared to polyethylene, polypropylene has a high melting point and does not heat-seal well, as it tends to crystallize after melting. Q: Is there any way of reducing or eliminating the number of insects that are drawn to backlit awning? A: Not that we know of. This is a natural scourge, which no amount of human involvement ha been able to alter through the centuries. Prices available upon request because there are so many different sizes of rolls, sq ft of purchase. GENERAL PROPERTIES OF POLYPROPYLENE MONONFILAMENT Polypropylene is a paraffin based fiber and is classified as an olefin. It is the lightest textile fiber, possesses high tensile strength, and excellent abrasion resistance. These properties make polypropylene monofilaments suitable for decorative fabrics. They are, for example, outdoor furniture, automotive fabrics and fiber cloths. Polypropylene monofilaments are available in pigmented colors added during the fiber manufacture — each monofilament is colored all the way through. This factor contributes to color stability. The following physical properties are listed to aid the textile manufacturer in developing a variety of fiber and fabric applications. GENERAL PROPERTIES SPECIFIC GRAVITY The specific gravity of polypropylene is 0.09-0.91. STIFFNESS The degree of stiffness can be modified by changes in the additive systems and production techniques. EFFECTS OF MOISTURE Polypropylene does not absorb moisture. LIGHT RESISTANCE By combining proper additives, the light stability of polypropylene is substantially improved. ABRASION RESISTANCE Polypropylene has excellent abrasion resistance. RESISTANCE: MILDEW AND INSECTS Insects and mildew do not attach to polypropylene. IDENTIFICATION Because of low specific gravity, polypropylene floats on water. Melting point: 325°F – 335°F. TENSILE PROPERTIES Polypropylene monofilaments have an averagetenacity range of 4-7 grams per denier. ELONGATION Polypropylene has an ultimate elongation of 14-30%. THERMAL PROPERTIES SOFTENING & MELTING TEMPERATURES Polypropylene will soften at 300°F – 310°F, and melts at 325°F – 335°F. SHRINKAGE Shrinkage at boil, 3-9% Shrinkage at 250°F, 5-12.5% FLAMMABILITY Polypropylene is difficult to ignite and upon burning melts to a bead. Proper additives can produce flame retardancy. CHEMICAL PROPERTIES Polypropylene polyolefm fiber has excellent chemical resistance to most acids, alkalis and salts. Polypropylene has good resistance to solvents at room temperature. CHEMICAL PERCENT CONCENTRATION °F TEMPERATURE LOSS OF TENSILE STRENGTH AFTER EXPOSURE OF 10 hours 75 hours 125 hours ACIDS Hydrochloric 5 72 none none none Nitric 10 72 none none none Sulfuric 10 72 none none none Acetic 10 72 none none none Oxalic 10 72 none none none ALKALIS Ammonium Hydroxide 10 72 none none none Sodium Hydroxide 10 72 none none none SALTS Sodium Hydro sulfite 10 72 none none none Sodium Chloride 10 72 none none none SOLVENTS Benzene 100 72 none none none Acetone 100 72 none none none Chlorothene 100 72 none none none OXIDIZINGAGENTS Hydrogen Peroxide 5 72 none none none Sodium Hypo chlorite 10 72 none none none Potassium Dichromate 10 72 none none none DOUBLE LAYER SHADE Many successful growers are using a double layer system of shade cloth as technology increases and economics demand maximum production and improved quality. The old methods of providing the proper summer shade and getting through the winter with inadequate light is too inefficient. Modern culture calls for proper light control during the brighter summer days. Acadian Industrial Textiles furnishes the table below as an aid in determining the correct combination of Shade Fabrics for your crops and conditions. These figures were obtained as in the following example: One layer of 30% shade cloth is letting 70% of the light through. Adding a layer of 55% shade would actually be shading 55% of the 70%, or 38.5%. Rounding this off and adding to the original 30% equals 69% shade. Studies need to be done to determine the effect of the distance between the two layers of fabric. Presently, the effect appears to be negligible. The table would not apply when two layers of lathe weave fabric are used. To use the table: find the shade of one layer in the left-hand column and then go horizontally across the table to the desired shade. When desired shade is found, look at the top row of numbers to determine the shade density of the layer needed to give desired shade. DOUBLE LAYER SHADE PERCENTAGES + 30 47 55 63 73 80 85 95 30 51 63 69 74 81 86 90 97 47 63 72 76 80 86 89 92 97 55 69 76 80 83 88 91 93 98 63 74 80 83 86 90 93 94 98 73 81 86 88 90 93 95 96 99 80 86 89 91 93 95 96 97 99 85 90 92 93 94 96 97 98 99 95 97 97 98 98 99 99 99 99 The above information is based on a mathematical calculation. Before installing double layer, we recommend that you perform actual testing with a shade box to determine the actual shade density.