TECHNICAL INFORMATION ABOUT UP-GF (GFRP)
PIPE SYSTEMS

Pipes made of glass fibre reinforced polyester resins (UP-GF)

Glass fibre reinforced plastic, abbreviated as GFRP (in German GFK = Glasfaserverstärkter Kunststoff), also referred to as duroplast, consists of plastic resin and a fibrous reinforcing material. Glass fibres impregnated with an unsaturated polyester resin (UP) or with a vinyl ester resin from the duroplast group, serve as reinforcement material.

In Germany, the vinyl ester resin is identified officially as phenactylate resin and is based for the types e.g. Derakane 411-350 or Distrotone VE 100 on bisphenol A and for the sorts e.g. Derakane 470-300 or DION 9400 on novolac resin.

Before processing, these resins are viscous solutions of so-called unsaturated polyesters, which are dissolved in copolymeriazable monomers (styrene). The final product GFRP consists of this plastic material and glass fibres. Good impregnation of the glass fibres with resin is of decisive importance for the product. Before impragnating the glasses accordingly by hand or automatically, radicals (peroxides) have to be added to the liquid resins, in order to imitate the reaction and to transfer the resin from the liquid state to a cross-linked state. .

During linking, no other fission products are produced. The solvent styrene will partly be released during processing. The process time takes 15 to 45 minutes and can be accelerated or slowed down by means of accelerators and/or inhibitors. With the three components (hardener, accelerator and inhibitor), the recipes are mixed individually according to the weather conditions and the necessary processing time and adapted to the specific processing performed.

Depending on recipe, starts within approximately 30 to 120 minutes an exothermic hardening reaction and warmth is released. This reaction brings about hardening of the unsaturated polyester resins under formation of cross-linked substances by means of copolymerization cured through radicals. With the styrene, the polyester molecules are forming network structures. A product manufactured like this can not be liquified by heating and not be dissolved by solvents (duroplast).

DIN 16 966 regulates specific designs, quality and audit of UP-GF fittings. This includes in particular

- Negative pressure load
- Layer structure and glass contents
- Styrene content
- Surface quality
- Behaviour towrads chemicals
- Adherence and rigidity
- Hygienic and toxicological safety
- Fire behaviour
- Dimensions
- Audit
- Short-time internal pressure tests

Kwerk.de delivers in addition to UP-GF pipe systems, known as pure GFRP, also UP-GF lining materials for fittings according to pipe type B.

Part of our delivery program are:

- PVC U plasticizer-free polyvinylchloride as per DIN 8061, colour grey
- PVC U plasticizer-free polyvinylchloride as per DIN 8061, colour red
- PVC C chlorienated polyvinylcloride as per DIN 8080
- PE-HD polyethylene of high density as per DIN 8075
- PP polypropylene as per DIN 8078
- PVDF polyvinylidenefluoride

Our UP-GF fittings are free from defects, like air bubbles and cracks. The laminate structure according to DIN 16966 is guaranteed for the entire length.
On principle, other UP-GF structures are available on request. During manufacture of UP-GF, all sealing surfacec and seams are properly laminated.

Our team, having nearly 40 years of work experience in production and application of UP-GF fittings and connections, will be pleased to answer any additional questions. Just call us: 0049 2602 999730