Grafting of silane on thermoplastics or elastomers for purposes of cross-linking
AssigneeKabel-und Metallwerke Gutehoffnungshutte Aktiengesellschaft
InventorsFritz Glander, Hermann Uwe Voigt
Life of this patent
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Abstract
Granulated polyethylene is agitated and mixed with a solution of silane with peroxide, activators and anti-oxidants and at a temperature between 80.degree. to 100.degree. C to obtain diffusion of these additives into the polyethylene particles which is followed by grafting through extrusion or radiation which in turn is followed by exposure to and/or development of water to obtain cross-linking. A catalyst is added preferably by mixing polyethylene powder with the catalyst and adding that powder to the powder with diffused silane, after that diffusion has been completed.
Claims12
In a method for providing a sheathing of cross-linking thermoplastic or elastomeric material, wherein the powdery or granular material is mixed with silane to be diffused into the material under conditions of obtaining a homogenic mixture and wherein the silane is grafted upon the molecules of the material, the improvement of adding water-containing additives to the mixture, and extruding a sheath, the water being released at an elevated temperature pursuant to the extrusion to cause cross-linking of the silane grafted material in the presence of moisture.
In a method for cross-linking thermoplastic or elastomeric material wherein a thermoplastic or elastomeric material is provided as dry, fluid powder, and to obtain fluidization thereof and raising the temperature by operation of the agitating, but below the crystallite melting range;
- and
- wherein a silane compound is added to the material prior to completion of the agitation to diffuse into the fluid particles, the silane compound being of the variety that permits grafting on the molecules of said powder;
- and
- wherein the silane or silane compound molecules are grafted onto the molecules of the thermoplastic or elastomeric material, the improvement comprising:
- adding about 0.05 to 5 parts by weight of at least one additive which develops water on decompositioning at elevated temperature, and extruding the silane grafted material to obtain internal release of water and cross-linking in an extruded product.
Dependencies are inferred from the claim text.