Method for preparing melamine resin foams using grinded melamine foam particles

Patent metadata

Field	Value
Publication number	US-2024270921-A1
Application number	US-202218569717-A
Country	US
Kind code	A1
Filing date	Jun 7, 2022
Priority date	Jun 17, 2021
Publication date	Aug 15, 2024
Grant date	—

Abstract

The present invention provides a process for producing a melamine resin foam comprising heating and foaming an aqueous mixture M using microwave radiation, said mixture M comprising melamine resin foam particles, at least one melamine-formaldehyde precondensate, at least one curative, at least one surfactant and at least one blowing agent as well as a process for recycling melamine resin foam scrap.

First claim

1 .- 12 . (canceled)

13 . A process for producing a melamine resin foam with a density in the range from 5 to 30 kg/m 3 comprising heating and foaming an aqueous mixture M using microwave radiation, said mixture M comprising melamine resin foam particles, at least one melamine-formaldehyde precondensate, at least one curative, at least one surfactant and at least one blowing agent.

14 . The process according to claim 13 , wherein the melamine-resin foam particles have a particle size distribution with a D 90 value below 150 μm, determined by microcopy.

15 . The process according to claim 13 , wherein the melamine resin foam particles have a bulk density in the range from 10-500 kg/m 3 .

16 . The process according to claim 13 , wherein the weight ratio of melamine resin foam particles to melamine-formaldehyde precondensate is in the range from 0.5/100 to 10/100.

17 . The process according to claim 13 , wherein said mixture M comprises a surfactant mixture comprising a mixture of 50 to 90 wt.-% of at least one anionic surfactant and 10 to 50 wt.-% of at least one nonionic surfactant, wherein the weight percentages are each based on the total weight of the surfactant mixture.

18 . The process according to claim 13 wherein formic acid is used as curative.

19 . The process according to claim 13 wherein pentane is used as blowing agent.

20 . A process for recycling melamine resin foam, wherein milled melamine resin foam scrap is used as melamine resin foam particles in the process according to claim 13 .

21 . A process according to claim 13 , wherein the density of the melamine resin foam is in the range from 8 to 20 kg/m 3 .

22 . A process for recycling melamine resin foam comprising the steps:
a) milling melamine resin foam scrap to foam flakes with a largest dimension in the range from 2-5 cm, b) milling the foam flakes from step a) to foam particles having a particle size distribution with a D 90 value below 150 μm, determined by light microscope or sieving, c) forming an aqueous mixture M from the foam particles from step b), at least one melamine-formaldehyde precondensate, at least one curative, at least one surfactant and at least one blowing agent, d) heating and foaming the aqueous mixture M using microwave radiation to produce a melamine resin foam, and e) optionally tempering the melamine resin foam obtained in step d) at a temperature between 120-300° C.

23 . A melamine resin foam obtained by the process of claim 13 .

24 . A method comprising utilizing the melamine resin foam according to claim 23 for acoustic and/or thermal insulation or for cleaning, grinding or polishing sponges.

Assignees

• Basf Se

Inventors

• Koenig Alexander
• Vath Bernhard
• Siegenthaler Kai Oliver
• Steinke Tobias Heinz

Classifications

• C08J2203/14

  Saturated hydrocarbons, e.g. butane; Unspecified hydrocarbons · CPC title

• C08J11/06

  without chemical reactions · CPC title

• C08J9/236

  using binding agents · CPC title

• C08J9/16

  Making expandable particles · CPC title

• C08J9/141

  Hydrocarbons · CPC title