After the extrusion, the process of the invention comprises a step of heating the initiator, mixed homogenously with the polymer material, by means of infared radiation in a wavelength range absorbed by the initiator. This can for example be achieved by a drying agent, preferably, a silane containing drying agent or by making an anhydride of the acid. Embodiments of the present disclosure generally relate to the production of cross-linked polyethylene. Following melt blending to form the silane-grafted polymer, the silane grafted polymer undergoes a moisture crosslinking or moisture curing process to form the silane cross-linked polyethylene. Reaction is started by injection of the radical initiator. The samples 1 through 4 were melt blended with different levels of Dynasylani. Examples of radical polymerization initiators include a organic peroxides such as lauroyl peroxide, dipropionyl peroxide, benzoyl peroxide, di-t-butyl peroxide, t-butyl hydroperoxide, and t-butyl peroxyisobutyrate; b molecular oxygen; and c azo compounds such as azobisisobutyronitrile and azoisobutylvalero- nitrile. Preferably the silane group containing comonomer units is represented by the formula: Wherein R 1 is an ethylenically unsaturated hydrocarbyl, hydrocarbyloxy or meth acryloxy hydrocarbyl group, R 2 is an aliphatic saturated hydrocarbyl group, Y which may be the same or different, is a hydrolysable organic group and q is 0, 1 or 2. According to one embodiment, the blend and the liquid are separately fed to the extruder.
Download scientific diagram | Procedures of Sioplas ® process. from publication: Citations These crosslinks inhibit the material deformation and flow at high.
Procedures of Sioplas ® process.
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+11 however, after cross-linking no flow would be noticed In the Sioplas® process, a mixture of silane component such as. For heinrichsmeier and cable applications this process requires use of rather elaborate and In the Sioplas process PE is treated with vinylsilane compound under.
In the moisture curing process, the silane-grafted polymer is subjected to a water bath or steam sauna to complete the crosslinking process.
Unexpectedly, the process of the current disclosure, in particular the addition of the maleating step to form the maleated polyethylene, results in a much more efficient use of silane monomers compared to conventional methods for manufacture of PEX-b. Short stops will also plug the extruder with crosslinked polymer and tool changing will require a complete cleaning of the cable extruder. A process as claimed in any one of claims 1 to 7characterized in that the peroxide used is dicumyl peroxide or di-tert-isobutyl peroxide.
In other embodiments, the molar ratio is 1.
Sioplas process mapping
|Even more preferably, the blend comprises all the additives of the composition to be formed, except for the silanol condensation catalyst and optionally the drying agent.
Examples of such optional monomers include a-olefins such as propylene, hexane-1 and 4-methylpentene-1 ; vinyl esters such as vinyl acetate and vinyl butyrate; unsaturated organic acid derivatives such as methyl acrylate and methyl methacrylate; unsaturated aromatic monomers such as styrene and a-methylstyrene; and vinyl ethers such as vinylmethyl ether and vinylphenyl ether.
Conventional polymer additives are for example, antioxidants, stabilizers e. This wavelength absorbs particularly into peroxide, but not into polyethylene, i.
Video: Sioplas process mapping Lean Six Sigma- From SIPOC to Process Mapping
FIB1 en. In other embodiments, the weight percent of peroxide is about 0. A process as claimed in any one of claims 1 to 5characterized in that the silane compound used is vinyltrimethoxysilane or vinyltriethoxysilane.
1 is a graph illustrating melt flow rates as measured by ASTM D at ° C. of extrusion. The Sioplas® process was developed in. by Midland Silicones. The essential step is peroxide-activated gra ing of the vinylsilane onto the polymer chains. Alternative Variations for Sioplas® and Monosil® Processes. however, after cross-linking no flow would be noticed Abbreviations.
In the extruder, the peroxide decomposes into radicals, which start the grafting of the silane groups onto the polymer chain.
The results of the tests performed on the cross-linked tapes are reported in Table 3 and compared to the results obtained for the inventive examples. This causes considerable energy costs both at the heating and cooling stages. Preferably the scorch retarder is included in the blend. The molar ratio of silane monomer and maleic anhydride on polypropylene is often aboutand can range from about to about Cables may be communication cables or more preferably electrical or power cables. USA1 en.
Process for CrossLinked Polyethylene Production Total American Services, Inc.
to consider during the development of a new Sioplas or Monosil process are: Melt flow index the initial polyethylene, density, polymerization process. The invention relates to a process of crosslinking a polymer material with silane the grafted product is crosslinked as in the above-described Sioplas process. to 3 used a commercially available LDPE polymer having a melt flow rate (MFR).
The process according to any of the preceding claims wherein the silanol condensation catalyst is metal containing Lewis acid.
Unless otherwise stated in the description or claims, the following methods were used to measure the properties defined generally above and in the claims and in the examples below. The total amount of additives in the blend may range from 0. Embodiments of the present disclosure include a method of producing cross-linked polyethylene and cross-linked polyethylene articles using maleic anhydride and a silane.