How are plastic sponges made?

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The Manufacturing Process The steps necessary in the manufacture of synthetic sponge is discussed below. The cellulose used for sponges arrives at the sponge factory in large, stiff sheets. Workers take the sheets and soak them in a vat of water mixed with certain chemical softeners. The cellulose becomes soft and jelly-like. Then workers load the cellulose into a revolving mixer, which is a large rotating metal drum. Workers add the sodium sulphate crystals, cut hemp fibers, and dye, and close the mixer. The mixer is set to rotate, and it churns the ingredients so that they are thoroughly amalgamated. From the mixer, workers pour the material into a large rectangular mold that may be 2 ft (61 cm) high, 2 ft (61 cm) wide, and 6 ft (1.8 m) long. The mold is heated, and the cellulose mixture cooks. As it cooks, the sodium sulphate crystals melt, and drain away through openings in the bottom of the mold. It is their melting that leaves the characteristic pores in the finished sponge. The size of the pores is determined by the size of the sodium sulphate crystals. A rough sponge used for washing a car, for instance, is made with coarse crystals, while a fine sponge of the type used for applying makeup is made with very fine crystals. As the celluolose mix cooks, then cools, it becomes a hard, porous block. The sponge block is then soaked in a vat of bleach. This removes dirt and impurities, and also brightens the color. Next the sponge is cleaned in water. Additional washings alter the texture, making the sponge more pliable. The sponge is left to dry, to prepare it for cutting. Some manufacturers make the sponge and cut and package it themselves. Others produce the raw blocks of sponge, and then sell them to a company known as a converter. The converter cuts the sponges according to its customers needs, and takes care of the packaging and distribution. Whether at the first manufacturing facility or at the converter, workers cut the sponges on an automatic cutter. They load each big rectangle of sponge into a machine that slices it into the desired size. Because the sponge block is rectangular, it can be cut into many smaller rectangles with little or no waste. Many household sponges have a textured plastic scouring pad attached to one side. This is attached in a process called laminating, after the sponge is cut. The scouring pad, which is cut to the same size as the sponge, is affixed to the sponge in a laminating Softened cellulose is mixed with sodium sulphate crystals, cut hemp fibers, and dye in a large, revolving metal drum. Once blended, the material is poured into a large rectangulor mold, which may be 2 ft (61 cm) high, 2 ft (61 cm) wide, and 6 h (182.9 cm) long. As the mold cooks, the sodium sulphate crystals melt, and drain away through openings in the bottom of the mold. It is their melting that leaves the characteristic pores in the finished sponge. machine that uses a specialized sponge glue made of moisture-cured polyurethane. Next, the sponges move to a packaging area where they are sealed in plastic. The packaged sponges are boxed, and the boxes sent to a warehouse for further distribution. http://www.madehow.com/Volume-5/Sponge.html Mar 20 10, 11:50 AM