HulshofKnittings

General

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A polyester is a polymer that exists from barracks of ester connections.

Polyesters are formed by a polycondensation response of dicarbonzuur and diol or by a polycondensation response of a large number of molecules with both a carboxylic acid and an alcohol group.

When for example a polyester is produced glycol and tereftaalzuur arise the polyester polyethylene tereftalaat (CAP). CAP is used for the production of soft drink bottles and for clothing.

Polyester can be both thermoplastic (under the influence of temperature melting) and thermohardende (under the influence of a chemical response uithardende) plastic.

The thermohardende polyester is a liquid mixture of onverzadigde polyester and styreen. These two bowl pinning komponenten can react under the influence of a hardener (peroxide) with each other to a hard plastic. These polyester is generally reinforced using glass fiber. This hot glass-fiber-reinforced polyester, but polyester is also frequently simply called. A well-known application to be zeiljachten and rowboats.

The processing of glass-fiber-reinforced polyester is possible in many ways. Most well-known technique is the handlamineren or in English hand lay-up. At this technique mats or fabrics on an open mal are impregnated with resin. This happens with a aspergillum or fleece roll-on. Then all air from the laminaat gerolt becomes with ontluchtingsroller. The desired cross-section of the laminaat is reached by the number of layers glass mat or glass fabric. This way still a lot of polyester products is made such as the wildwaterbanen of Centreparcs, canoes, all kinds of beschermkappen for machines and such.

Another manner to introduce resin is with a needle machine. This machine has a large and small pump with which respectively resin and the hardener to a needle gun are pumped. On the needle gun a cutter sits that ongoing invoked glasroving in small bits chops and this glass sipping press with the resin jet spouts. After the glass/polyester mixture on the mal has been spouted must this with ontluchtingsroller be bled. Well-known examples of this technique its polyester garden ponds, it 50 meters long bus station at head village and the strengthening layer on the back of plastic ligbaden.

At above techniques is released during the processing styreen. Although these styreendamp do not form a large danger directly at sufficient ventilatie penetrating fetidness can ensure, however, nuisance. For the styreenemissie to occur a number of processing techniques where a closed mal is used, has been developed. Examples are vacuum injection, vacuum injection under foil, light-RTM, drukinjectie or RTM (resin decal moulding). At these techniques in advance glass mat becomes and/or glass fabrics on a mal laid, the mal is whereupon closed with contramal. By means of vacuum (vacuum injection) or show through (drukinjectie) or a combination of busy and vacuum vervolgens the resin in the mal, therefore between the glass fibers, is sucked or is pressed. This way nowadays even complete scheepsrompen of some dozens of meters length in one time are made

Still a much use technique is winding to fail and tanks. A long ongoing cord glass fibers is conducted by a bath with polyester and on a turning around mal is vervolgens wound. This way the voedersilo's are for example made at pig units and much control work in the chemical industry.

Still very other processing techniques for onverzadigde polyester resin are pultrusietechniek, SMC-perstechniek, presses and pouring polymer concrete.