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Method for nanoclays and carbon nanotubes as flame retardant additives for halogen-free substrate cores

IP.com Disclosure Number: IPCOM000146447D
Publication Date: 2007-Feb-13
Document File: 2 page(s) / 20K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for nanoclays and carbon nanotubes as flame retardant additives for halogen-free substrate cores. Benefits include improved functionality, improved performance, improved reliability, and improve environmental friendliness.

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Method for nanoclays and carbon nanotubes as flame retardant additives for halogen-free substrate cores

Disclosed is a method for nanoclays and carbon nanotubes as flame retardant additives for halogen-free substrate cores. Benefits include improved functionality, improved performance, improved reliability, and improve environmental friendliness.

Background

      Conventional substrates typically use bromide or phosphorus based compounds as flame-retardant fillers in core materials. However, government regulations increasingly require halogen-free cores. As a result, alternative filler materials must be developed.

      The conventional solution is aluminum trihydrates, which have a very high loading requirement (up to 30 wt.%). However, they result in poor processibility and a deterioration of the core’s mechanical and adhesion properties.

      An alternate solution uses nanoclays to decrease the heat release rate of ethyl vinyl acetate (EVA). For example, loadings of <10 wt.% induce a ~50% decrease in the heat release rate. The decrease is equated with an increase in flame retardancy. It is attributed to the formation of a thermally insulating, low permeable char. The nanometer-scale clay platelets have a high specific surface area that protects the polymer by preferentially charring. This characteristic has led to investigation into using nanoclays as flame retardant additives to polymeric substrate cores. However, the addition of only nanoclays can increase polymer cracking.

      A conventional technique used to manufacture polymer-based composites is the melt blending of the polymer with the nanoclay and nanotube additives. The method uses sufficient agitation to eliminate any large filler agglomerates that may be adverse to the mechanical properties of the composite produced.

      Another conventional technique dissolves the relevant monomer in a suitable carrier/solvent and disperses the fillers with surfactants to avoid agglomeration. The solvent is dried and the monomer is cured to obtain the required polymer composite and well-dispersed fillers. F...