Window frame

Rigid PVC profiles are joined into a domestic window frame.

Window frame, illustrative image

Material

uPVC frame profiles: PVC

Material selection rationale

Rigid formulation
Keeps the frame's cross-section in shape.
Profile extrusion
Hollow chambers and sealing channels can run along the frame.
Multi-chamber profile
Internal walls and chambers create stiffness and thermal separation without filling the whole section with solid PVC.

How it becomes a product

  1. Extrude the profiles: Unplasticised PVC compound is pushed through a shaped die and cooled.
  2. Join the frame: Lengths are cut and corners welded; seals, hardware and glazing are fitted separately. Extruded lengths are cut and joined; glazing, seals and any reinforcement contribute functions outside the PVC trace.

Preparation routes

Vinyl chloride route

Free-radical addition polymerisation. Vinyl chloride molecules link into PVC chains. The resin is then formulated differently for rigid pipes and flexible coverings. The original double bond is consumed, while the C–Cl bonds remain in the repeat unit. Flexible and rigid PVC can therefore have the same polymer origin.

An initiator starts chain growth. Stabilising additives and, for flexible formulations, plasticisers are separate from the monomer. Plasticiser acts mainly by altering chain mobility; it is not a second polymerising feedstock.

  1. PVC: monomer production, polymerisation and usesChemical Industry Education Centre, University of York

From ethene to vinyl chloride

  1. Ethene + Chlorine → 1,2-Dichloroethane

    Direct chlorination adds chlorine across ethene's double bond.

  2. 1,2-Dichloroethane → Chloroethene

    Industrial cracking removes hydrogen chloride, leaving the double bond in vinyl chloride.

  1. PVC: monomer production, polymerisation and usesChemical Industry Education Centre, University of York

Sources

  1. EURO-DESIGN 70 PVC window profilesREHAU
  2. REHAU: development of extruded PVC window profilesREHAU
  3. PVC: monomer production, polymerisation and usesChemical Industry Education Centre, University of York