Flame-resistant polyurea foam

• US 5,719,200 A
• Filed: 07/01/1996
• Issued: 02/17/1998
• Est. Priority Date: 03/25/1994
• Status: Expired due to Fees

• Current Assignee: Clariant GmbH (Clariant AG)
• Original Assignee: Hoechst Aktiengesellschaft (Sanofi )
• Inventors: Lagoda, Reinhold, Staendeke, Horst
• Primary Examiner(s): Foelak, Morton
• Application Number:
  US08/586,681
• Time in Patent Office: 596 Days
• Field of Search: 521/106, 521/120, 521/123, 521/128, 521/159, 521/906
• US Class Current: 521/106
• CPC Class Codes: C04B 14/00 Use of inorganic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of inorganic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone expanding or defibrillating materials C04B20/00
• CPC Class Codes: C04B 2103/63 Flame-proofing agents
• CPC Class Codes: C04B 22/145 Gypsum from the desulfuration of flue gases
• CPC Class Codes: C04B 26/16 Polyurethanes
• CPC Class Codes: C04B 38/02 by adding chemical blowing agents
• CPC Class Codes: C08G 18/10 Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
• CPC Class Codes: C08G 18/302 Water
• CPC Class Codes: C08G 2110/0041 having specified density
• CPC Class Codes: C08G 2110/0083 prepared using water as the sole blowing agent
• CPC Class Codes: C08G 2350/00 Acoustic or vibration damping material
• CPC Class Codes: C09K 3/32 for absorbing liquids to remove pollution, e.g. oil, gasoline, fat
• CPC Class Codes: Y10S 521/906 Polyurethane cellular product containing unreacted flame-retardant material

Abstract

The flame-resistant polyurea foam of the invention contains calcium sulfate dihydrate as filler and ammonium polyphosphate as flame retardant. Its bulk density is from 25 to 250 kg/m³ and the number of open cells is above 80% of all its cells. The polyurea has been formed from a reaction of prepolymers of diphenylmethane 4,4'"'"'-diisocyanate with water.

The polyurea foam of the invention can be used as a block foam or on-site foam for sound and/or heat insulation.

Claims

1. A flame-resistant polyurea foam which

- contains calcium sulfate dihydrate,

- contains, as flame retardant, ammonium polyphosphate,

- has a bulk density of from 25 to 250 kg/m³,

- has a number of open cells which is above 80% of all its cells,

- comprises polyurea which has been formed from a reaction of prepolymers of diphenylmethane 4,4'"'"'-diisocyanate with water.

2. A polyurea foam as claimed in claim 1, wherein said flame retardant is combined with a further halogen-free flame retardant, a halogen-free synergist, or a combination thereof.

3. A polyurea foam as claimed in claim 1, wherein said calcium sulfate dihydrate is natural gypsum or chemical gypsum.

4. A polyurea foam as claimed in claim 1, which contains, as flame retardant, a free-flowing, pulverulent ammonium polyphosphate of the formula (NH₄ PO₃)_n having n=20 to 1000 which is sparingly soluble in water.

5. A polyurea foam as claimed in claim 4, wherein, in said formula (NH₄ PO₃)_n, n is from 500 to 1000.

6. A polyurea foam as claimed in claim 4, wherein the ammonium polyphosphate is microencapsulated and contains from 5 to 25% by mass of a water-insoluble, synthetic resin which encloses the individual ammonium polyphosphate particles and which, optionally, has been cured.

7. A polyurea foam as claimed in claim 1, which has a bulk density of from 35 to 90 kg/m³.

8. A polyurea foam as claimed in claim 1, containing the following components in % by mass:

a) from 15 to 70% of polyurea,

b) from 25 to 80% of calcium sulfate dihydrate,

c) from 1 to 15% of flame retardant,

and, optionally, the following components in % by mass;

d) from 0.1 to 5% of a fibrous filler,

e) from 0.1 to 2% of catalysts based on nitrogen compounds for the isocyanate/water reaction,

f) from 0.1 to 2% of foam stabilizers based on polysiloxanes,

g) from 0.01 to 2% by weight of auxiliaries for dispersion and/or suspension and/or providing thixotropy.

9. A polyurea foam as claimed in claim 8, wherein the amounts of said components a) through c) are as follows:

a) from 20 to 60%, b) from 30 to 70%, and c) from 2 to 10%, and, when said component d) is present, the amount of component d) is from 0.2 to 2%.

10. An insulating material comprising a polyurea foam as claimed in claim 1.

11. An insulating material as claimed in claim 10, wherein said material is in the form of a block foam or an on-site foam.