Modified polyphenylene ether resin foam sheet

Abstract

This invention provides a foamed sheet, which is a modified polyphenylene ether resin foamed sheet with good formability and processability. It exhibits very low relative permittivity and dielectric loss factor at high frequencies, and possesses self-extinguishing or flame-retardant properties, along with excellent surface characteristics. The modified polyphenylene ether resin foamed sheet of this invention is produced by foaming a modified polyphenylene ether resin containing both a halogen-based flame retardant and a phosphorus-based flame retardant with a weight-average molecular weight of 1,000 to 1,000,000 as flame retardants. The average bubble diameter of the bubbles in the modified polyphenylene ether resin foamed sheet is 1–30 μm, and the bubble number density is 1.8 × 10⁴ to 9 × 10⁸ bubbles / mm³.

Claims

1. A modified polyphenylene ether resin foamed sheet, characterized in that: it is made by foaming a modified polyphenylene ether resin containing both a halogen-based flame retardant and a phosphorus-based flame retardant with a weight average molecular weight of 1,000 to 1,000,000 as flame retardants, and the average bubble diameter of the bubbles in the modified polyphenylene ether resin foamed sheet is 1 to 30 μm, and the bubble number density is 1.8×10⁴ to 9×10⁸ bubbles / mm³.

2. The modified polyphenylene ether resin foamed sheet as claimed in claim 1, wherein the average bubble diameter of the bubbles in the modified polyphenylene ether resin foamed sheet is 1 to 22 μm and the bubble number density is 2.0×104 to 8×108 bubbles / mm3.

3. The modified polyphenylene ether resin foamed sheet as claimed in claim 1, wherein the average thickness of the modified polyphenylene ether resin foamed sheet is 0.05 mm to 2.0 mm.

4. The modified polyphenylene ether resin foamed sheet as requested in item 1, wherein the modified polyphenylene ether resin foamed sheet is used, and the flame retardancy is evaluated according to the UL-94 vertical method (20 mm vertical burning test) of the US UL standard, and the test results meet the V-0 or V-1 standard.

5. The modified polyphenylene ether resin foamed sheet as claimed in claim 1, wherein the modified polyphenylene ether resin foamed sheet is used for housings of electrical and electronic components, electrical insulation materials, sealing materials, protective materials, high-frequency substrates, or substrates for electromagnetic wave control components.

6. A housing, electrical insulation material, sealing material, protective material, high-frequency substrate, or electromagnetic wave control component substrate for electrical and electronic parts, which is obtained by using a modified polyphenylene ether resin foam sheet as claimed in any one of claims 1 to 5.