CA2046235A1 - Flame and smoke reduced high density polyurethane foams - Google Patents
Flame and smoke reduced high density polyurethane foamsInfo
- Publication number
- CA2046235A1 CA2046235A1 CA002046235A CA2046235A CA2046235A1 CA 2046235 A1 CA2046235 A1 CA 2046235A1 CA 002046235 A CA002046235 A CA 002046235A CA 2046235 A CA2046235 A CA 2046235A CA 2046235 A1 CA2046235 A1 CA 2046235A1
- Authority
- CA
- Canada
- Prior art keywords
- weight
- polyurethane foam
- parts
- melamine
- urea
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/16—Nitrogen-containing compounds
- C08K5/21—Urea; Derivatives thereof, e.g. biuret
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/30—Low-molecular-weight compounds
- C08G18/38—Low-molecular-weight compounds having heteroatoms other than oxygen
- C08G18/3819—Low-molecular-weight compounds having heteroatoms other than oxygen having nitrogen
- C08G18/3823—Low-molecular-weight compounds having heteroatoms other than oxygen having nitrogen containing -N-C=O groups
- C08G18/3829—Low-molecular-weight compounds having heteroatoms other than oxygen having nitrogen containing -N-C=O groups containing ureum groups
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/30—Low-molecular-weight compounds
- C08G18/38—Low-molecular-weight compounds having heteroatoms other than oxygen
- C08G18/3819—Low-molecular-weight compounds having heteroatoms other than oxygen having nitrogen
- C08G18/3842—Low-molecular-weight compounds having heteroatoms other than oxygen having nitrogen containing heterocyclic rings having at least one nitrogen atom in the ring
- C08G18/3851—Low-molecular-weight compounds having heteroatoms other than oxygen having nitrogen containing heterocyclic rings having at least one nitrogen atom in the ring containing three nitrogen atoms in the ring
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/40—High-molecular-weight compounds
- C08G18/48—Polyethers
- C08G18/4804—Two or more polyethers of different physical or chemical nature
- C08G18/4816—Two or more polyethers of different physical or chemical nature mixtures of two or more polyetherpolyols having at least three hydroxy groups
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/40—High-molecular-weight compounds
- C08G18/48—Polyethers
- C08G18/487—Polyethers containing cyclic groups
- C08G18/4883—Polyethers containing cyclic groups containing cyclic groups having at least one oxygen atom in the ring
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/16—Nitrogen-containing compounds
- C08K5/34—Heterocyclic compounds having nitrogen in the ring
- C08K5/3467—Heterocyclic compounds having nitrogen in the ring having more than two nitrogen atoms in the ring
- C08K5/3477—Six-membered rings
- C08K5/3492—Triazines
- C08K5/34922—Melamine; Derivatives thereof
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G2110/00—Foam properties
- C08G2110/0025—Foam properties rigid
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G2110/00—Foam properties
- C08G2110/0041—Foam properties having specified density
- C08G2110/0066—≥ 150kg/m3
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G2110/00—Foam properties
- C08G2110/0083—Foam properties prepared using water as the sole blowing agent
Abstract
FLAME AND SMOKE REDUCED HIGH DENSITY POLYURETHANE FOAM
Abstract of the Disclosure This invention relates to rigid polyurethane foams having densities from about 13 lb/ft3 to about 30 lb/ft3 which exhibit reduced flammability and smoke generating characteristics. This is accomplished by reacting an aromatic isocyanate with a polyhydroxy containing compound, a blowing agent, optional additives, and incorporating a combination of melamine and urea into the unreacted polyhydroxy containing resin.
Abstract of the Disclosure This invention relates to rigid polyurethane foams having densities from about 13 lb/ft3 to about 30 lb/ft3 which exhibit reduced flammability and smoke generating characteristics. This is accomplished by reacting an aromatic isocyanate with a polyhydroxy containing compound, a blowing agent, optional additives, and incorporating a combination of melamine and urea into the unreacted polyhydroxy containing resin.
Description
FLAME AND SMOKE RED~CED ~IG~ DENSITY POLYURETHANE POAMS
BACKGROUND OF THE INVENTION
Field of the Invention The invention relates to rigid, high density polyurethane foams exhibiting reduced flammability and smoke generating characteristics, and a method of preparing said foams. The invention relates to any rigid polyurethane foams having a high density but is particularily concerned with those foams having densities of from about 13 lbs/ft3(pcf) (208 kg/m3) to about 30 lbs/ft3(pcf) (480 kg/m3). The reduced flammability and smoke generating characteristics are attained by adding melamine and urea as additives.
Background of the Invention Various methods for preparing polyurethane foams having reduced flammability or smoldering combustion characteristics are known in the art. U.S Patent No.
4,221,875 teaches the preparation of a rigid polyurethane which incorporates 20 to 100 parts by weight melamine in the formulations as the sole flame retardant compound. U.S.
Pat. ~o. 4,385,131 teaches a method of combining a melamine-urea mixture with pieces of a cured flexible polyurethane foams and a noncellular binder to produce rebond foams 20~623~
resistant to smoldering combustion. West German Patent ~o.
~E 2,348,838 discloses a method of preparing an isocyanurate containing rigid or semi-rigid polyurethane foam using melamine as the flame proofing agent.
Other references disclose the preparation of polyurethane foams using melamine as a fire retardant additive either alone or in combination with other materials such as silica, alumina, halogenated phosphorous ester compounds, and the like. However, none of the references disclose a melamine-urea mixture as an additive in rigid, high density, polyurethane foam formulations, wherein the mixture will impart a desired level of resistance to flammability and smoke generation.
Summarv of the Invention The present invention relates to a modified rigid, high density polyurethane foam, and to a method for preparing said foam. In particular the invention concerns an improved, modified, rigid, high density polyurethane foam and its preparation wherein the modified foam contains melamine and urea which as exclusive additives impart resistance to flammability and smoke generation. It should be noted however that it is not outside the scope of the invention for the foam to contain minor amounts of other . . ... ..
20~23S
flame retardants, e.g. halogenated phosphorous estes compounds and the like.
The foam itself is comprised of the reaction product of an aromatic isocyanate with a polyhydroxy containing compound in the presence of a catalyst as needed, a blowing agent, a surfactant as needed, other optional additives and melamine/urea as the exclusive flame retardant and smoke inhibiting additives.
Any aromatic polyisocyanate may be used in the practice of the instant invention. Typical aromatic polyisocyanates include m-phenylene diisocyanate, p-phenylene diisocyanate, polymethylene polyphenylisocyanate, 2,4-toluene diisocyanate, 2,6-tolylene diisocyanate, dianisidine diisocyanate, bitolylene diisocyanate, naphthalene-1,4-diisocyanate, diphenylene-4,4'-diisocyanate, aliphatic-aromatic diisocyanates, such as xylylene-1,4-diisocyanate, xylylene-1,2-diisocyanate, xylylene-1,3-diisocyanate, bis(4-isocyanatophenyl methane, bis(3-~ethyl-4-isocyanatophenyl) methane, and 4,4'-diphenylpropane diisocyanate.
Preferred aromatic polyisocyanates used in the practice of the invention are methylene-bridged polyphenyl polyisocyanate miYtures which have a functionality of from 2~62~
about 2 to about 4. These latter isocyanate compounds are generally produced by the phosgenation of corresponding methylene bridged polyphenyl polyamines~ which are conventionally produced by.the reaction of formaldehyde and primary aromatic amines, such as aniline, in the presence of hydrochloric acid and/or other acidic catalysts. Known processes for preparing the methylene-bridged polyphenyl polyamines and corresponding methylene-bridged polyphenyl polyisocyanates therefrom are described in the literature and in many patents, for example, U.S. Patent Nos.
2,683,730; 2,950,263; 3,012,008 3,344,162; and 3,362,979.
The more preferred aromatic polyisocyanate used in the practice of the invention is polymeric diphenylmethane diisocyanate (MDI) having a nominal functionality of three.
Representative polyhydroxy containing compounds which may be employed in the preparation of the rigid high density polyurethane foam of the subject invention are well known to those skilled in the art. They are often prepared by the catalytic condensation of an alkylene oxide or mixture of alkylene oxides either sequentially or simultaneously with one or more organic compounds having at least two active hydrogen atoms, such as evidenced by U.S.
Patent Nos. 1,922,459; 3,190,927; and 3,346,557.
2~23S
Any suitable polyoxyalkylene polyether polyol may be used such as the polymerization product of an alkylene oxide or a mixture of alkylene oxides with a polyhydric alcohol. Any suitable alkylene oxide may be used such as ethylene oxide, propylene oxide, butylene oxide, amylene oxide, and mixtures of these oxides. The polyoxyalkylene polyether polyols may be prepared from other starting materials such as tetrahydrofuran and alkylene oxide-tetrahydrofuran mixtures; epihalohydrins such as epichlorohydrin; as well as aralkylene oxides such as styrene oxide. The polyoxyalkylene polyether polyols may have either primary or secondary hydroxyl groups. Included among the the polyether polyols are polyoxyethylene glycol, polytetramethylene glycol, block copolymers, for example, combinations of polyoxypropylene and polyoxyethylene glycols, poly-1,2-oxybutylene and polyoxyethylene glycols, poly-1,4-oxybutylene and polyoxyethylene glycols, and random copolymer glycols prepared from blends of two or more alkylene oxides or by the ~equential addition of two or more alkylene oxides. The polyoxyalkylene polyether polyols may ~e prepared by any known process such as, for example, the proce~s disclosed by Wurtz in 1859 and Encyclopedia of Chemical ~echnology, Vol. 7, pp. 257-262, published by ~0~623S
Interscience Publishers, Inc. (19~1) or in U.S. Pat. ~o.
1,922,459. Polyethers which are preferred include the alkylene oxide addition products of trimethylolpropane, glycerine, pentaerythritol, sucrose, sorbitol, propylene glycol and 2,2'-l4,4'-hydroYyphenyl)propane, dipropylene glycol, water and mixtures thereof.
The more preferred embodiments include mixtures of alkylene oxide addition products containing an addition product of sucrose. The polyoxyalkylene addition products may be alone or in combination with other hydroxy containing compounds such as the off stream residue and by-products of hexanediol distillation which contains a mixture which is primarily C5-C6 diols. The most preferred polyether polyol is a propylene oxide adduct of sucrose and dipropylene glycol.
Any suita~le catalyst may be used including tertiary amines or long chain metal salts (fatty acid salts) commonly referred to as trimer or isocyanurate catalyst. An example of a tertiary amine i5 triethylene diamine available commercially under the DABC0~ 33LV trademark. An example of a fatty acid salt is potassium octoate available commercially under the designation ~ex Chem 977.
. .
20~623~
In the production of the rigid, high density polyurethane foams of the present invention other known additives are necessary. One ~uch constituent is the blowing agent. Some examples of uch materials are the halogenated hydrocarbons, such as trichlorofluoromethane;
low-boiling hydrocarbons, such as butane or pentane:
however, in this case the preferred blowing agent is water.
Other additives known to those having skill in the art which may be used in the preparation of the foams used in the present invention include surfactants and chain extenders~ In general, noni~nic surfactants are suitable for use in the invention, with the well known silicones such as the polysiloxanes being particularly advantageous. Chain extending agents which may be employed in the preparation of the polyurethane foams of this invention include those compounds having at least two functional groups bearing active hydrogen atoms. A preferred compound used in this regard is diethanolamine.
~ he invention principally relates to the discovery that a combination of melamine and urea is capable of replacing other more expensive conventional flame retardant additives in high density rigid polyurethane foams and lend both flame retardant and lower smoke generating characteristics to the foam.
.. . ... . . . . . . . . .
20~6235 The most preferred form of melamine is a powder, used in an amount of about 32 parts by weight based on 140 ~art~ by weiqht of polyol. ~he particle size of the melamine powder is not crit~ical tG the invention and any particle size range between 1 and 100 microns is suitable.
In a preferred aspect of the invention, melamine powder desi~nated as superfine (-100~ < 30 microns; mean particle size 20 microns) is used.
The preferred form of the urea used is a powder.
In general particle size is not critical to the invention, and any range of particle sizes allowing effective dispersal in the polyol i6 acceptable. In a preferred embodiment the urea has a particle size range from about 10 to about 250 microns. To obtain the preferred particle size the urea may be subject to crushing. The method used to crush the urea is not critical to the invention. Some techniques for obtaining the preferred particle size include crushing in a ball mill prior to addition to the polyol, subjecting to high shear mixing after addition to the polyol, or pouring urea-polyol mixture through a three roll mill. The amount of urea used ranges from about 32 to about 72 parts by weight based on 140 parts by weight polyol.
20~623~
In general the order of addition of nonisocyanate components is not critical. ~owever, if the urea is not of the ~esired particle size and crushing is to be done in situ it has been found to be advantageous to perform the crushing prior to addition of the other components.
Suitable processes for the preparation of cellular polyurethane foams are known to those having skill in the art. No particular method is critical to the invention. By way of example such methods of preparation may include; the "one shot" technique where the components may be reacted in a single working step. Alternatively, it is possible to proceed with the preparation of the foam by a prepolymer technique wherein an excess of organic polyisocyanate is reacted in a first step with the polyol of the present invention to prepare a prepolymer having free isocyanate groups which is then reacted in a second step with water and/or additional polyol to prepare a foam.
The following examples illustrate the nature of the invention. All parts are by weight unless otherwise stated. In the examples, the physical properties were determined by the following ASTM tests:
Density - D1622-63 Smoke - E662-83 F~ame, Test - 3014-76 ., . ~
.
20~235 The following abbreviations are used in the examples below.
Polyol A is a propylene oxide adduct of sucrose and dipropylene glycol having a hydroxyl number of 395 and a molecular weight of 620.
Polyol B is a propylene oxide adduct of sucrose and dipropylene glycol having a hydroxyl number of 300 and a molecular with of 800.
Polyol C is a propylene oxide adduct of glycerine having a hydroxyl number of 230 and a molecular weight of 730.
DEOA i5 diethanolamine.
DC-193~ is a silicone surfactant consisting of polysiloxane produced by Air Products.
DABCO~ 33 LV is triethylene diamine in dipropylene glycol.
K+Octoate is potassium octoate in diethylene glycol.
~ DI is polymeric diphenylmethane diisocyanate.
F-ll is monofluorotrichloromethane.
Melamine used is superfine (100% particles < 30 microns)~
Index refers to the isocyanate index which is a ratio of the actual amount of i ocyanate used in the formulation to the theoretical amount reguired. Generally ~0~23~
given as a percentage. The calculation for determining the isocyanate index is as follows:
Dbw~ Isocyanate = equivalent weight x pbw Polyol x hydroxyl no.
index l~ocyanate 56100 ~pbw = parts by weight 2~23~
Examples 1-2 Urea and polyol were charged to a vessel and mixed at room temperature using a high shear mixer. The urea-polyol component was then poured through a three roll mill. All other nonisocyanate components were added with stirring. A predetermined amount of MDI was then added to the resin and mixed thoroughly with a high speed mixer for about 10 seconds.
The resin was then poured into preheated (49C) aluminum molds and allowed to cure. The ~moke tests were run on foam plaques made in molds of the following dimensions, ~"x8"x8". The flame tests were run on foam plaques of the following dimensions, l"x8"x8".
Example 1 Example 2 Polyol C 42.0 70.0 Polyol A 98.0 70.0 DEOA 0.5 0 5 Water 1.0 1.0 Melamine 32.0 32.0 Urea 32.0 32.0 K+Octoate 3.0 3.0 ~DI
200 Index 275.1 251.4 250 Index 343.9 314.2 Density (pcf)/(kcm) 24.0/384 24.0/384 Smoke Results Example 11 2 2 Index 200 250 200 250 5 min Smoke 23/45 39/31 53/46 27/37 10 min. Smoke 82/84 67/65 132/109 145/51 Flame Out (min.) 15/12 13/13 13/11 11/11 End of ~est (min.)20/17 20/17 15/15 14/19 Final Smoke 121/118 102/82 136/141 153/108 204~23~
Flame Test Example _ 1 2 2_ Index 200 250 200 250 Ave. Wt. Ret. (wt~) 97.2 97.3 95.24 97.42 Examples 3-5 Preparation same as 1 and 2.
Exam~le 3 ExamPle 4 Example 5 Polyol B 140.0 140.0 140.0 DEOA 0.5 0.5 0.5 Water 1.0 1.0 1.0 Melamine 32.0 32.0 32.0 Urea 44.0 56.0 68.0 K+Octoate 3.0 3.0 3.0 MDI
200 Index240.9 240.9 240.9 Density tpcf)/(kcm) 24.0/384 24.0/384 24.0/384 Smoke Results Example 3 4 5 Index 200 200 200 5 min. Smoke 17/127 21/18 -/11 10 min. Smoke 98/162 46/34 65/23 Flame Out (min.) 11/9 14/14 13/15 End of Test (min.) 18/14 20/22 17/23 Final Smoke 126/153 102/108 131/72 Flame Test Example 3 4 5 Index 200 200 20 Ave. Wt. Ret. (wt%) 98.5 98.7 98.8 , 204~23~
Examples 6-11 Preparation ~ame as 1-2 Ex 6 Ex 7 Ex 8 EX 9 Ex t O Ex 11 Polyol A70.0 140.0 140.0 140.0 140.0 140.0 Polyol E70.0 -- -- -_ -_ __ DC-193 1.0 1.0 1.0 1.0 1.0 1.0 Melamine32.0 32.0 32.0 32.0 32.0 32.0 Urea -- 32.0 ô.0 16.0 24.0 40.0 ~ater 1.0 1.0 1.0 1.0 1.0 1.0 DA~C0~ 33LV1.O -- -- __ __ 0.3/0.2/ _**
MDI
110 Index127.4 155.4 155.4 155.4 155.4 155.4 Density (pcf)* 28.5/24.4 25.2/25.0 25.5/23.6 27.8/24.6 24.7/24.5 24.2/22.1/23.1 (kcm) 456/390403/400 408/378 445/394 395/393 387/354/370 ~ The first value indicates the density for the ~" plaque the next value indicates the density for the 1" plaque.
~* The 1" plaques were made the first having 0.2 pbw catalyst the ~econd having no catalyst.
Smoke Test Example 6 7 8 9 10 11 Index 110 110 110 110 109 110 5 mln. Smoke 46 117 53/87 117/77 71/33 185/109 10 min. Smoke 92 329 98/249 196/109 122/71 460/221 Flame Out (min.) 9.5 6 11.5/11 12/13 15.5/14 7/12 End of Test (min.) 17 10 16/13 13/20 18/18 12/15 Final Smoke 183 314 171/297 184/109 193/115 460/216 Flame Test Example 6 7 8 9 10 lndex 110 110 110 110 110 110 Ave. Wt. Ret. (wt~)78.1 95.5 75.8 76.4 75.6 95.0/92.6
BACKGROUND OF THE INVENTION
Field of the Invention The invention relates to rigid, high density polyurethane foams exhibiting reduced flammability and smoke generating characteristics, and a method of preparing said foams. The invention relates to any rigid polyurethane foams having a high density but is particularily concerned with those foams having densities of from about 13 lbs/ft3(pcf) (208 kg/m3) to about 30 lbs/ft3(pcf) (480 kg/m3). The reduced flammability and smoke generating characteristics are attained by adding melamine and urea as additives.
Background of the Invention Various methods for preparing polyurethane foams having reduced flammability or smoldering combustion characteristics are known in the art. U.S Patent No.
4,221,875 teaches the preparation of a rigid polyurethane which incorporates 20 to 100 parts by weight melamine in the formulations as the sole flame retardant compound. U.S.
Pat. ~o. 4,385,131 teaches a method of combining a melamine-urea mixture with pieces of a cured flexible polyurethane foams and a noncellular binder to produce rebond foams 20~623~
resistant to smoldering combustion. West German Patent ~o.
~E 2,348,838 discloses a method of preparing an isocyanurate containing rigid or semi-rigid polyurethane foam using melamine as the flame proofing agent.
Other references disclose the preparation of polyurethane foams using melamine as a fire retardant additive either alone or in combination with other materials such as silica, alumina, halogenated phosphorous ester compounds, and the like. However, none of the references disclose a melamine-urea mixture as an additive in rigid, high density, polyurethane foam formulations, wherein the mixture will impart a desired level of resistance to flammability and smoke generation.
Summarv of the Invention The present invention relates to a modified rigid, high density polyurethane foam, and to a method for preparing said foam. In particular the invention concerns an improved, modified, rigid, high density polyurethane foam and its preparation wherein the modified foam contains melamine and urea which as exclusive additives impart resistance to flammability and smoke generation. It should be noted however that it is not outside the scope of the invention for the foam to contain minor amounts of other . . ... ..
20~23S
flame retardants, e.g. halogenated phosphorous estes compounds and the like.
The foam itself is comprised of the reaction product of an aromatic isocyanate with a polyhydroxy containing compound in the presence of a catalyst as needed, a blowing agent, a surfactant as needed, other optional additives and melamine/urea as the exclusive flame retardant and smoke inhibiting additives.
Any aromatic polyisocyanate may be used in the practice of the instant invention. Typical aromatic polyisocyanates include m-phenylene diisocyanate, p-phenylene diisocyanate, polymethylene polyphenylisocyanate, 2,4-toluene diisocyanate, 2,6-tolylene diisocyanate, dianisidine diisocyanate, bitolylene diisocyanate, naphthalene-1,4-diisocyanate, diphenylene-4,4'-diisocyanate, aliphatic-aromatic diisocyanates, such as xylylene-1,4-diisocyanate, xylylene-1,2-diisocyanate, xylylene-1,3-diisocyanate, bis(4-isocyanatophenyl methane, bis(3-~ethyl-4-isocyanatophenyl) methane, and 4,4'-diphenylpropane diisocyanate.
Preferred aromatic polyisocyanates used in the practice of the invention are methylene-bridged polyphenyl polyisocyanate miYtures which have a functionality of from 2~62~
about 2 to about 4. These latter isocyanate compounds are generally produced by the phosgenation of corresponding methylene bridged polyphenyl polyamines~ which are conventionally produced by.the reaction of formaldehyde and primary aromatic amines, such as aniline, in the presence of hydrochloric acid and/or other acidic catalysts. Known processes for preparing the methylene-bridged polyphenyl polyamines and corresponding methylene-bridged polyphenyl polyisocyanates therefrom are described in the literature and in many patents, for example, U.S. Patent Nos.
2,683,730; 2,950,263; 3,012,008 3,344,162; and 3,362,979.
The more preferred aromatic polyisocyanate used in the practice of the invention is polymeric diphenylmethane diisocyanate (MDI) having a nominal functionality of three.
Representative polyhydroxy containing compounds which may be employed in the preparation of the rigid high density polyurethane foam of the subject invention are well known to those skilled in the art. They are often prepared by the catalytic condensation of an alkylene oxide or mixture of alkylene oxides either sequentially or simultaneously with one or more organic compounds having at least two active hydrogen atoms, such as evidenced by U.S.
Patent Nos. 1,922,459; 3,190,927; and 3,346,557.
2~23S
Any suitable polyoxyalkylene polyether polyol may be used such as the polymerization product of an alkylene oxide or a mixture of alkylene oxides with a polyhydric alcohol. Any suitable alkylene oxide may be used such as ethylene oxide, propylene oxide, butylene oxide, amylene oxide, and mixtures of these oxides. The polyoxyalkylene polyether polyols may be prepared from other starting materials such as tetrahydrofuran and alkylene oxide-tetrahydrofuran mixtures; epihalohydrins such as epichlorohydrin; as well as aralkylene oxides such as styrene oxide. The polyoxyalkylene polyether polyols may have either primary or secondary hydroxyl groups. Included among the the polyether polyols are polyoxyethylene glycol, polytetramethylene glycol, block copolymers, for example, combinations of polyoxypropylene and polyoxyethylene glycols, poly-1,2-oxybutylene and polyoxyethylene glycols, poly-1,4-oxybutylene and polyoxyethylene glycols, and random copolymer glycols prepared from blends of two or more alkylene oxides or by the ~equential addition of two or more alkylene oxides. The polyoxyalkylene polyether polyols may ~e prepared by any known process such as, for example, the proce~s disclosed by Wurtz in 1859 and Encyclopedia of Chemical ~echnology, Vol. 7, pp. 257-262, published by ~0~623S
Interscience Publishers, Inc. (19~1) or in U.S. Pat. ~o.
1,922,459. Polyethers which are preferred include the alkylene oxide addition products of trimethylolpropane, glycerine, pentaerythritol, sucrose, sorbitol, propylene glycol and 2,2'-l4,4'-hydroYyphenyl)propane, dipropylene glycol, water and mixtures thereof.
The more preferred embodiments include mixtures of alkylene oxide addition products containing an addition product of sucrose. The polyoxyalkylene addition products may be alone or in combination with other hydroxy containing compounds such as the off stream residue and by-products of hexanediol distillation which contains a mixture which is primarily C5-C6 diols. The most preferred polyether polyol is a propylene oxide adduct of sucrose and dipropylene glycol.
Any suita~le catalyst may be used including tertiary amines or long chain metal salts (fatty acid salts) commonly referred to as trimer or isocyanurate catalyst. An example of a tertiary amine i5 triethylene diamine available commercially under the DABC0~ 33LV trademark. An example of a fatty acid salt is potassium octoate available commercially under the designation ~ex Chem 977.
. .
20~623~
In the production of the rigid, high density polyurethane foams of the present invention other known additives are necessary. One ~uch constituent is the blowing agent. Some examples of uch materials are the halogenated hydrocarbons, such as trichlorofluoromethane;
low-boiling hydrocarbons, such as butane or pentane:
however, in this case the preferred blowing agent is water.
Other additives known to those having skill in the art which may be used in the preparation of the foams used in the present invention include surfactants and chain extenders~ In general, noni~nic surfactants are suitable for use in the invention, with the well known silicones such as the polysiloxanes being particularly advantageous. Chain extending agents which may be employed in the preparation of the polyurethane foams of this invention include those compounds having at least two functional groups bearing active hydrogen atoms. A preferred compound used in this regard is diethanolamine.
~ he invention principally relates to the discovery that a combination of melamine and urea is capable of replacing other more expensive conventional flame retardant additives in high density rigid polyurethane foams and lend both flame retardant and lower smoke generating characteristics to the foam.
.. . ... . . . . . . . . .
20~6235 The most preferred form of melamine is a powder, used in an amount of about 32 parts by weight based on 140 ~art~ by weiqht of polyol. ~he particle size of the melamine powder is not crit~ical tG the invention and any particle size range between 1 and 100 microns is suitable.
In a preferred aspect of the invention, melamine powder desi~nated as superfine (-100~ < 30 microns; mean particle size 20 microns) is used.
The preferred form of the urea used is a powder.
In general particle size is not critical to the invention, and any range of particle sizes allowing effective dispersal in the polyol i6 acceptable. In a preferred embodiment the urea has a particle size range from about 10 to about 250 microns. To obtain the preferred particle size the urea may be subject to crushing. The method used to crush the urea is not critical to the invention. Some techniques for obtaining the preferred particle size include crushing in a ball mill prior to addition to the polyol, subjecting to high shear mixing after addition to the polyol, or pouring urea-polyol mixture through a three roll mill. The amount of urea used ranges from about 32 to about 72 parts by weight based on 140 parts by weight polyol.
20~623~
In general the order of addition of nonisocyanate components is not critical. ~owever, if the urea is not of the ~esired particle size and crushing is to be done in situ it has been found to be advantageous to perform the crushing prior to addition of the other components.
Suitable processes for the preparation of cellular polyurethane foams are known to those having skill in the art. No particular method is critical to the invention. By way of example such methods of preparation may include; the "one shot" technique where the components may be reacted in a single working step. Alternatively, it is possible to proceed with the preparation of the foam by a prepolymer technique wherein an excess of organic polyisocyanate is reacted in a first step with the polyol of the present invention to prepare a prepolymer having free isocyanate groups which is then reacted in a second step with water and/or additional polyol to prepare a foam.
The following examples illustrate the nature of the invention. All parts are by weight unless otherwise stated. In the examples, the physical properties were determined by the following ASTM tests:
Density - D1622-63 Smoke - E662-83 F~ame, Test - 3014-76 ., . ~
.
20~235 The following abbreviations are used in the examples below.
Polyol A is a propylene oxide adduct of sucrose and dipropylene glycol having a hydroxyl number of 395 and a molecular weight of 620.
Polyol B is a propylene oxide adduct of sucrose and dipropylene glycol having a hydroxyl number of 300 and a molecular with of 800.
Polyol C is a propylene oxide adduct of glycerine having a hydroxyl number of 230 and a molecular weight of 730.
DEOA i5 diethanolamine.
DC-193~ is a silicone surfactant consisting of polysiloxane produced by Air Products.
DABCO~ 33 LV is triethylene diamine in dipropylene glycol.
K+Octoate is potassium octoate in diethylene glycol.
~ DI is polymeric diphenylmethane diisocyanate.
F-ll is monofluorotrichloromethane.
Melamine used is superfine (100% particles < 30 microns)~
Index refers to the isocyanate index which is a ratio of the actual amount of i ocyanate used in the formulation to the theoretical amount reguired. Generally ~0~23~
given as a percentage. The calculation for determining the isocyanate index is as follows:
Dbw~ Isocyanate = equivalent weight x pbw Polyol x hydroxyl no.
index l~ocyanate 56100 ~pbw = parts by weight 2~23~
Examples 1-2 Urea and polyol were charged to a vessel and mixed at room temperature using a high shear mixer. The urea-polyol component was then poured through a three roll mill. All other nonisocyanate components were added with stirring. A predetermined amount of MDI was then added to the resin and mixed thoroughly with a high speed mixer for about 10 seconds.
The resin was then poured into preheated (49C) aluminum molds and allowed to cure. The ~moke tests were run on foam plaques made in molds of the following dimensions, ~"x8"x8". The flame tests were run on foam plaques of the following dimensions, l"x8"x8".
Example 1 Example 2 Polyol C 42.0 70.0 Polyol A 98.0 70.0 DEOA 0.5 0 5 Water 1.0 1.0 Melamine 32.0 32.0 Urea 32.0 32.0 K+Octoate 3.0 3.0 ~DI
200 Index 275.1 251.4 250 Index 343.9 314.2 Density (pcf)/(kcm) 24.0/384 24.0/384 Smoke Results Example 11 2 2 Index 200 250 200 250 5 min Smoke 23/45 39/31 53/46 27/37 10 min. Smoke 82/84 67/65 132/109 145/51 Flame Out (min.) 15/12 13/13 13/11 11/11 End of ~est (min.)20/17 20/17 15/15 14/19 Final Smoke 121/118 102/82 136/141 153/108 204~23~
Flame Test Example _ 1 2 2_ Index 200 250 200 250 Ave. Wt. Ret. (wt~) 97.2 97.3 95.24 97.42 Examples 3-5 Preparation same as 1 and 2.
Exam~le 3 ExamPle 4 Example 5 Polyol B 140.0 140.0 140.0 DEOA 0.5 0.5 0.5 Water 1.0 1.0 1.0 Melamine 32.0 32.0 32.0 Urea 44.0 56.0 68.0 K+Octoate 3.0 3.0 3.0 MDI
200 Index240.9 240.9 240.9 Density tpcf)/(kcm) 24.0/384 24.0/384 24.0/384 Smoke Results Example 3 4 5 Index 200 200 200 5 min. Smoke 17/127 21/18 -/11 10 min. Smoke 98/162 46/34 65/23 Flame Out (min.) 11/9 14/14 13/15 End of Test (min.) 18/14 20/22 17/23 Final Smoke 126/153 102/108 131/72 Flame Test Example 3 4 5 Index 200 200 20 Ave. Wt. Ret. (wt%) 98.5 98.7 98.8 , 204~23~
Examples 6-11 Preparation ~ame as 1-2 Ex 6 Ex 7 Ex 8 EX 9 Ex t O Ex 11 Polyol A70.0 140.0 140.0 140.0 140.0 140.0 Polyol E70.0 -- -- -_ -_ __ DC-193 1.0 1.0 1.0 1.0 1.0 1.0 Melamine32.0 32.0 32.0 32.0 32.0 32.0 Urea -- 32.0 ô.0 16.0 24.0 40.0 ~ater 1.0 1.0 1.0 1.0 1.0 1.0 DA~C0~ 33LV1.O -- -- __ __ 0.3/0.2/ _**
MDI
110 Index127.4 155.4 155.4 155.4 155.4 155.4 Density (pcf)* 28.5/24.4 25.2/25.0 25.5/23.6 27.8/24.6 24.7/24.5 24.2/22.1/23.1 (kcm) 456/390403/400 408/378 445/394 395/393 387/354/370 ~ The first value indicates the density for the ~" plaque the next value indicates the density for the 1" plaque.
~* The 1" plaques were made the first having 0.2 pbw catalyst the ~econd having no catalyst.
Smoke Test Example 6 7 8 9 10 11 Index 110 110 110 110 109 110 5 mln. Smoke 46 117 53/87 117/77 71/33 185/109 10 min. Smoke 92 329 98/249 196/109 122/71 460/221 Flame Out (min.) 9.5 6 11.5/11 12/13 15.5/14 7/12 End of Test (min.) 17 10 16/13 13/20 18/18 12/15 Final Smoke 183 314 171/297 184/109 193/115 460/216 Flame Test Example 6 7 8 9 10 lndex 110 110 110 110 110 110 Ave. Wt. Ret. (wt~)78.1 95.5 75.8 76.4 75.6 95.0/92.6
Claims (10)
1. A rigid, high density polyurethane foam comprising the reaction product of:
A) an aromatic organic isocyanate, B) a component containing isocyanate reactive hydroxyl groups selected from the group consisting of C5 to C6 diols, polyether polyols having molecular weights of from about 500 to 1300 and functionalities of at least about three, wherein at least one initiator of said polyethers is sucrose, and mixtures thereof;
C) optionally a catalyst;
D) a blowing agent;
E) optionally a silicone surfactant;
F) optionally a chain extender;
and G) melamine and urea as the flame and smoke retardant additives, wherein at least 32 pbw each of melamine and urea are present based on 140 pbw B).
A) an aromatic organic isocyanate, B) a component containing isocyanate reactive hydroxyl groups selected from the group consisting of C5 to C6 diols, polyether polyols having molecular weights of from about 500 to 1300 and functionalities of at least about three, wherein at least one initiator of said polyethers is sucrose, and mixtures thereof;
C) optionally a catalyst;
D) a blowing agent;
E) optionally a silicone surfactant;
F) optionally a chain extender;
and G) melamine and urea as the flame and smoke retardant additives, wherein at least 32 pbw each of melamine and urea are present based on 140 pbw B).
2. The polyurethane foam as claimed in claim 1, wherein said foam has a density of from about 13 pcf (208 kg/m3) to about 30 pcf (480 kg/m3).
3. The polyurethane foam as claimed in claim 1, wherein said component containing isocyanate reactive hydroxyl groups is selected exclusively from polyether polyols having initiators selected from the group consisting of sucrose, water, dipropylene glycol, glycerine, and mixtures thereof, wherein sucrose must be one of the initiators present.
4. The polyurethane foam as claimed in claim 1, wherein the aromatic isocyanate is polymeric diphenylmethane diisocyanate.
5. The polyurethane foam as claimed in claim 1, wherein the catalyst is triethylenediamine in dipropylene glycol.
6. The polyurethane foam as claimed in claim 1, wherein said catalyst is potassium octoate in diethylene glycol.
7. The polyurethane foam as claimed in claim 1, wherein the blowing agent is water.
8. The polyurethane foam as claimed in claim 1, wherein said surfactant is polysiloxane.
9. The polyurethane foam as claimed in claim 1, wherein said chain extender is diethanolamine.
10. A rigid, high density, polyurethane foam comprising the reaction product of:
A) a polymeric diphenylmethane diisocyanate present in amounts sufficient to provide an index of from about 110 to about 300, wherein said index represents the ratio of the actual amount of isocyanate used, to the theoretical amount required expressed as a percentage;
B) a propylene oxide adduct based on initiators selected from the group consisting of sucrose, dipropylene glycol, glycerine, and mixtures thereof, wherein a polyoxypropylene adduct of sucrose must be present:
C) 0 to 3.0 parts by weight of a trimer catalyst based on 140 parts by weight B);
D) up to 1.0 part by weight of water as a blowing agent based on 140 parts by weight B):
E) 0 to 1.0 parts by weight of a silicone surfactant based on 140 parts by weight B);
F) 0 to 0.5 parts by weight of diethanolaine based on 140 parts by weight B); and G) 64 to 136 parts by weight of a melamine-urea mixture, wherein melamine constitutes at least 32 parts by weight of the melamine-urea mixture based on 140 parts by weight B).
A) a polymeric diphenylmethane diisocyanate present in amounts sufficient to provide an index of from about 110 to about 300, wherein said index represents the ratio of the actual amount of isocyanate used, to the theoretical amount required expressed as a percentage;
B) a propylene oxide adduct based on initiators selected from the group consisting of sucrose, dipropylene glycol, glycerine, and mixtures thereof, wherein a polyoxypropylene adduct of sucrose must be present:
C) 0 to 3.0 parts by weight of a trimer catalyst based on 140 parts by weight B);
D) up to 1.0 part by weight of water as a blowing agent based on 140 parts by weight B):
E) 0 to 1.0 parts by weight of a silicone surfactant based on 140 parts by weight B);
F) 0 to 0.5 parts by weight of diethanolaine based on 140 parts by weight B); and G) 64 to 136 parts by weight of a melamine-urea mixture, wherein melamine constitutes at least 32 parts by weight of the melamine-urea mixture based on 140 parts by weight B).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US54865890A | 1990-07-05 | 1990-07-05 | |
| US07/548,658 | 1990-07-05 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2046235A1 true CA2046235A1 (en) | 1992-01-06 |
Family
ID=24189820
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002046235A Abandoned CA2046235A1 (en) | 1990-07-05 | 1991-07-04 | Flame and smoke reduced high density polyurethane foams |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA2046235A1 (en) |
| GB (1) | GB2258870A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2070717B1 (en) | 2007-12-10 | 2013-05-15 | Folex Coating GmbH | Method for mounting a rubber blanket in offset printing |
| WO2013021039A1 (en) | 2011-08-11 | 2013-02-14 | Basf Se | Microwave absorbing composition |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4385131A (en) * | 1981-06-18 | 1983-05-24 | Wm. T. Burnett & Co., Inc. | Polyurethane foam resistant to smoldering combustion containing either urea or melamine |
| GB8826727D0 (en) * | 1988-11-15 | 1988-12-21 | Bp Chem Int Ltd | Melamine/urea containing polymer polyols |
| AT394049B (en) * | 1989-04-04 | 1992-01-27 | Chemie Linz Gmbh | MELAMINE PREPARATION, STABLE DISPERSION OF MELAMINE IN POLYETHEROLS, METHOD FOR THE PRODUCTION AND THEIR USE |
| GB2232676A (en) * | 1989-06-13 | 1990-12-19 | Basf Corp | Polyurethane compositions exhibiting reduced smoke density and method of preparing same |
-
1991
- 1991-07-04 CA CA002046235A patent/CA2046235A1/en not_active Abandoned
- 1991-08-21 GB GB9118012A patent/GB2258870A/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| GB2258870A (en) | 1993-02-24 |
| GB9118012D0 (en) | 1991-10-09 |
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