DE2423993A1 - URETHANE MODIFIED POLYISOCYANURATE FOAMS - Google Patents

Description

25 352 n / wa

ICI AMERICA. INC., WILMINGTON, DELAWARE / USA

Urethane-modified polyisocyanurate foams

The invention relates generally to polyisocyanurate foams, which have good fire retardant properties and reduced friability, and on masses that are used for Production of such foams can be used.

Polyurethane foams made by implementing an active

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Hydrogen-containing compound generated with an organic polyisocyanate are known. They are one A variety of active hydrogen-containing compounds, such as polyols, including both polyethers as well as polyesters have been described. One of the properties of polyurethane foams is their usability for certain forms of application, the The foams have a tendency to burn, especially when exposed to an open flame.

There are also polyisocyanurate foams that are formed by polymerization of an isocyanate have been described. These materials have improved high temperature properties compared to the polyurethanes and are inherently fire retardant. However, these materials are what crumbly excludes their use in some forms of application. the As used herein, the term "friability" refers to the tendency of the foam to crumble or crumble to be crushed into a powder.

In previous attempts to reduce the friability of the polyisocyanurate foams, the addition of one or several active hydrogen containing compounds to the mass used to manufacture these materials have been included. The effect of the active hydrogen containing material lies in the introduction of tirethane linkages into the resulting foam, which is modified as urethane Polyisocyanurate foam is called, which reduces the crosslink density of the foam and the friability will. A variety of hydroxyl group-containing compounds have been proposed for this application. Before-

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beaten links are disclosed in U.S. Patents 3,625,872 and US Pat GB-PS 1 104 394. The materials suggested in these and other known references include a variety of polyesters and polyethers. However, when these additives are applied it occurs in addition to reducing the friability of the foam, there is a corresponding decrease in fire-retardant properties of the foam.

Reducing the friability of the foam without significantly reducing its fire retardant properties would therefore be desirable.

According to the invention, fire-retardant polyisocyanurate foams are used generated from a foam-forming mass, which is a. Isocyanate, a catalyst, a blowing agent, a surfactant Comprises agent and a polyol, the composition being characterized in that the polyol has the formula having:

H (OR ¹ ) 0 O.

O (R'O) _b H

wherein R is an alkylidene group with 1 to 4 carbon atoms,

a cycloalkylidene group of 5 to 6 carbon atoms, oxygen, sulfur or a group of the formula O

Il

C = O; or S = O;

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represents;

X halogen or y an alkyl group of 1 to 3 carbon atoms means;

η is an integer from zero to four;

R ^{1 is} an alkylene group of 2 to 4 carbon atoms or the radical ~ CH ₂ CH0-; and

a and b represent integers that are at least one and where the sum is at least four.

As mentioned above, according to the invention, polyisocyanurate foams are described which have fire retardant properties and reduced friability. In the description herein, the fire retardant foams are defined in terms of their weight retention when measured by the method set forth as the Butler Chimney Test in the Journal of Cellular Plastics , Volume 3, 1967 at page 497. When tested in this manner, the foams of the invention are characterized by weight retention greater than about 75%. In addition to the fact that the polyisocyanurate foams according to the invention are fire-retardant, they generally have a greatly reduced friability, unlike those known from the prior art. The friability of the foams is measured here in accordance with ASTM Standard Test C421-61. When tested in this way, the foams of the invention are friable by eAe

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characterized by less than about 50%.

The improved polyisocyanurate foams according to the invention are preferably generated from a mass that

(a) a polyether polyol,

(b) an isocyanate

(c) a catalyst,

(d) a propellant, and

(e) a surfactant

includes. Each of these components is described in detail below.

Isocyanate

The isocyanates used according to the invention may include those proposed according to the prior art for the production of polyisocyanurate foams have been. These include both di- and polyisocyanates, as well as aromatic and aliphatic isocyanates. Representative Isocyanates that can be used include, for example, tolylene diisocyanate; para-phenylene diisocyanate; 1-methoxyphenylene 2,4-diisocyanate; Diphenylene 4,4-diisocyanate; Toluene 2,4,6-triisocyanate; 1-ethylbenzene 2,4-diisocyanate; Triphenylmethane 4,4 ·, 4 '' - triisocyanate; Diphenylmethane diisocyanate; Xylylene diisocyanate; bis-cyclohexylmethane diisocyanate; Naphthalene diisocyanate; and isophorone diisocyanate.

In addition to the fact that the isocyanates that can be used have a functionality that at least

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is about 2.0, they should have a molecular weight of at least 160. When using isocyanates with lower molecular weight it has been found that satisfactory foams are not obtained.

Polyol

Polyether polyol used in the invention can, by reacting a dihydric alcohol such as bisphenol A or a substituted bisphenol A with an alkylene oxide such as ethylene oxide, Propylene oxide and butylene oxide or with styrene oxide. It has been found, however, to produce of the foams according to the invention, it is critical that the amount of alkylene oxide or styrene oxide reacted is sufficient must be to at least 4-alkylene or -CH-CH-phenyl groups introduce into the molecule. If there are fewer than about four of these units in the molecule, it has been found that there is no marked reduction in friability of the foams compared to those that do can be obtained with other polyethers. It was also found that the friability was further increased by the introduction of more than about 4 alkylene or -CH-CH-phenyl units in the Molecule can be reduced However, if the number of units introduced is greater than about 12, it has been found that that when the friability of the foams is reduced, there is a simultaneous reduction in the fire-retardant property. As mentioned above, this is undesirable. The use of polyols in which the sum of a + b in the The formula given above gives about 4 to about 12, is therefore preferred. Particularly preferred results are with

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Polyols have been obtained which have an average value of a + b equal to about 5 to about 10. Two particularly preferred polyols are those in which a + b = 6 or 9.

Representative polyols that can be used include, for example, polyoxyethylene (4) -bis- (4-hydroxyphenyl) propane;. Polyoxystyrene (6) bis (2,6-dibromo-4-hydroxypheny 1) methane; Polyoxybutylene (6) bis (4-hydroxyphenyl) ketone; Polyoxyethylene (9) bis (4-hydroxyphenyl) ether; Polyoxystyrene (4) bis (2,6-dichloro-4-hydroxyphenyl) thioether; Polyoxypropylene (12) bis (4-hydroxyphenyl) sulfone; Polyoxystyrene (9) bis (2,6-dimethyl-4-hydroxyphenyl) ethane; Polyoxyethylene (5) bis (2,3,5,6-tetrabromo-4-hydroxyphenyl) butane; Polyoxyethylene (10) bis (4-hydroxyphenyl) cyclohexane; Polyoxypropylene (6) "bis (4-hydroxyphenyl) sulfoxide.

The use of polyols within the formula given above, wherein

R ^{1 represents} an alkylene group having 2 to 3 carbon atoms, η is zero, and

R is an alkylidene group with 3 carbon atoms,

is particularly preferred.

In the production of the polyisocyanurate foams according to In the invention, preferred results have been obtained when a mixture of 2 or more of the above Polyols have been applied in the foam-forming composition. It was found that when using a mixture of polyols, the one associated with foam formation

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Reaction conversion or the reaction rate can easily be controlled, whereby the masses in a wide variety of applications are useful.

Preferred mixtures are those in which an ethylene oxide derivative has one of the dihydric alcohols defined above a propylene oxide, butylene oxide or styrene oxide derivative of one of the dihydric alcohols is combined. Particularly preferred Results are with a combination of a polyether prepared by reacting ethylene oxide and bisphenol A as above described, has been produced, with a polyether, produced by the reaction of propylene oxide with bisphenol A, also as indicated above, has been obtained. The relative amount of each polyol in the blend can be varied widely and is not stated been found that they are critical within very narrow limits for the production of the improved polyisocyanurate foams according to of the invention. Thus, mixtures containing about 10 to about 90% by weight of polyol made from ethylene oxide and about 90 to about 10% by weight of a further polyol within the above formula, preferably in those according to the invention Masses are applied.

The total amount of polyol in the foam-forming mass is used is preferably equal to or less than the amount necessary to react with about 20% of the isocyanate (-NCO) groups in bulk is required. This preferred maximum amount of polyol can be determined according to the following formula:

_{xo # 2} o] equiv. P = grams P Aq.wt. I I

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Gram I means the total amount in grams of isocyanate applied;

Equivalent weight I relates to the equivalent weight of the isocyanate - i.e. the number of grams of the isocyanate, which is necessary to introduce an -NCO group into the mass;

Equivalent weight P refers to the equivalent weight of the polyol or polyol mixture - i.e. the number the gram of polyol required to introduce a hydroxyl (-0H) group into the mass; and

Gram P refers to the amount of polyol that can be applied in the bulk.

Thus if 100 g of a crude methylene diisocyanate which has an equivalent weight of 137 - i.e. an -NCO group for every 137 grams - and a polyol having an equivalent weight of 280 - i.e. one hydroxyl group To add to every 280 grams - the preferred amount of polyol should be up to about 41 grams be equal. This amount is determined as follows:

χ 0.20) 280 = 41

In the same way, if a polyol that has an equivalent weight of 344 is employed, preferably up to about 50 grams of the polyol is added. Though less than this Amount of polyol can also be applied, it has been found that when reducing the amount of polyol the improved friability also decreases. It is therefore preferred to use the maximum amount of polyol that we like is determined above.

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catalyst

Catalysts previously described for use in the production of isocyanurate foams can be used in accordance with the invention. Representative catalysts that can be used include, for example, N-alkylmorpholines such as N-methylmorpholine and N-ethylmorpholine; tertiary amines, such as trimethylamine, triethylamine, tetramethylguanidine, triethylenediamine, Ν, Ν, Ν ', Ν ^1- tetramethy1-1,3-butanediamine; Piperazine and piperazine derivatives such as N-methylpiperazine; Tin catalysts including dialkyltin laurates, such as dibutyltin dilaurate, dibutyltin bis (2-ethylhexoate), dibutyltin diacetate, tin (II) oleate and tin (II) octoate; Potassium acetate; Sodium methylate; Diacetyl; Lead naphthenate; Lead octoate; Mannich bases such as 2,4,6-tris (dimethylaminomethyl) phenol and combinations of DABCO (1,4-diazabicyclo-2,2,2-octane) and epoxides.

It is also possible to use catalyst mixtures. The amount of catalyst or mixture of catalysts used can vary over a wide range depending on the preparation used and the type of catalyst, what is known to those skilled in the art. In most forms of application, the catalyst will either applied as a single compound or as a mixture of compounds in an amount ranging from 1 to 10 parts by weight per 100 parts by weight of the total preparation is the same.

Propellant

Polyisocyanurate foams are made when low boiling Liquids, gaseous propellants or blowing agents

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incorporated into or through the isocyanurate-forming reactants these are formed. Applicable blowing agents include, for example, any of those conventionally used in the manufacture Polyurethane foams are applied, including for example water; the chlorinated and fluorinated alkanes, which have 1 to about 3 carbon atoms, such as chlorofluoromethanes, Chlorofluorobutanes and chlorofluoroethanes, including for example trichlorofluoromethane (Freon 11), monochloroethane, Monochloromonofluoroethane, 1,2-dibromo-1,1,2,2-tetrafluoroethane, 1,1,2-trifluoroethane, 1,1,2,2-tetrafluoro-1,2-dichloroethane, 1,2-difluoro-1,1,2,2-tetrachloroethane, dichloromethane, Dibromomethane and mixtures thereof.

The amount of blowing agent employed is preferably sufficient to produce a foam having a nominal density of about 2 - i.e. from 1.5 to 2.5. However, either more or less than this amount of propellant can be used in the manufacture of foams according to the invention can be used. It should be noted here, however, that with the increase the density of the foam decreases the friability or brittleness, which is why the improved properties of the foams according to FIG Invention for foams of increased density are less pronounced.

Surface active agents

When propellants are incorporated into the isocyanurate-forming reactants or are generated by these, a stabilizing agent is generally included in the mass, the function of which is to regulate the amount or quality of the foamed polyisocyanurate obtained. Without the stabilizing agents or surface active agents

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the foams can either collapse or contain very large and irregular cells. Representative surfaces Agents that can be used include surfactants generally used in the manufacture of polyurethane foams can be applied. These include silicone surfactants and nonionic surfactants Agents such as the siloxane-oxyalkylene block copolymers disclosed in U.S. Patent 2,834,748 (issued to Bailey et al) are described. Other surfactants that can be used, represent condensates of ethylene oxide with a hydrophobic base, which by condensation of Propylene oxide can be formed with a propylene glycol. These surfactants have a molecular weight within of the range from about 2000 to about 8000, where they are generally assigned the formula:

HO (C ₂ H ₄ O) _a (C ₃ H ₆ O) _b . (C ₂ H ₄ O) _c H

Another class of surfactants includes Alkylene oxide adducts of ethylenediamine, which are generally the Have formula:

fm (C ₂ H ₄ O) _y (c ₃ H ₆ o _x _7 ₂

N (CH ₂ ) ₂ N / OC ₃ H ₆ ) _x (OC ₂ H ₄ ) _y OH 7

Another class of surfactants includes the polyoxyalkylene esters of long-chain fatty acids and sorbitan (derivatives) such as polyoxyethylene (20) sorbitan monolaurate, polyoxyethylene (4) sorbitan monolaurate, polyoxyethylene (20) sorbitan tristearate, Polyoxyethylene (20) sorbitan monooleate, polyoxyethylene (5) sorbitan monooleate and polyoxyethylene (20) sorbitan trioleate.

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The amount of surfactants applied can be over a wide range depending on, for example the applied foam-forming mass and the properties desired in the end product can be varied. For In most applications, the surfactant is applied in an amount / which is 0.5 to 1.6 parts by weight each 100 parts by weight of the total batch or the total preparation is equivalent.

The foam-forming compositions according to the invention can also include a variety of additives such as those commonly used in the manufacture of polyisocyanurate foams can be applied. These can include, for example, flame retardants, such as tris (chloropropyl) phosphate and tris-ß-chloropropyl phosphate lock in. Other additives such as colorants, plasticizers and contrast agents can also be used can be applied.

In carrying out the invention, the so-called "one-shot" methodology is used usually used to generate foam at room temperature. In this process, all components i.e. the isocyanate, the polyol, the blowing agent, the catalyst and the surfactant is simultaneously mixed with one another in any suitable manner and then applied to a surface poured where the foaming reaction takes place.

There are several suitable types of blending devices, that can be applied. The mixing device can have any number of lines leading to it for introduction of the various components. For example, a line can be for each constituent or a number

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be provided on lines that is less than the number of different components. If the number of lines is less than the total number of ingredients used, it is of course necessary to use several of the To combine components before introducing them into the mixing device. The ingredients can be of any suitable type Be combined in a manner, the only requirement being in it insists that premature reaction should not occur prior to introduction into the mixer.

Alternatively, a pre-polymer technique can be used in the Production of the foams according to the invention can be used. According to this technique, part of the reaction associated with the production of the polyisocyanurate foam is carried out, whereby a prepolymer of increased molecular weight is obtained, and the prepolymer subsequent to production of the desired polyisocyanurate product applied. When using a prepolymer technique, it is preferred to use a portion of the »polyol to react with the isocyanate to produce the prepolymer.

The reduced friability or fragility of the fire-retardant, Polyisocyanurate foams produced according to the invention represent a distinct advantage. As mentioned above are polyisocyanurate foams that have the combined fire retardant and brittleness properties of those of the invention, not previously available. These foams are particularly useful in applications such as insulation Lamination and in a variety of other applications especially useful where corrugated foam materials have been found useful. The foams can be used either as sheet

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material or pellet material are produced, which is or can subsequently be processed for the desired end use be foamed for example by spraying or pouring at the place where they are ultimately used.

The following examples are given to provide a clearer understanding of the invention. These examples are only for Illustration as to why the specific details given herein are not to be regarded as limitations.

The following standard tests were used in evaluating the foams produced here.

The fire retardancy of the foams was measured according to the Butler Chimney Test, as described in J. Cellular Plastics , Volume 3, 497 (1967). The fire retardancy is expressed in percentage weight retention. A higher value therefore indicates a more fire-retardant foam.

The percent fragility or friability of the foams was determined according to A.S.T.M. Standard test C421-61 measured. This Test involves measuring the weight loss of the foam after it has been in was spun on a drum, the results being expressed in terms of percent weight loss are. A lower value indicates a less brittle foam.

All components in the foaming compositions are given in parts by weight. To the foam-forming used in the examples To be able to describe the masses more comfortably, they are

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Components identified by their trademarks or a representative symbol. The trademarks used in the examples or symbols are identified as follows:

Rubinat M refers to an isocyanate that has a functionality of about 2.7 and an equivalent weight of 135 and is commercially available from Rubicon Chemicals Co. is. "

L-5340 and L-5420 refer to surfactants Silicones available from Union Carbide Corporation, New York, New York.

Solution A refers to a catalyst solution that Comprises 20 g of potassium acetate, 20 g of ethylene glycol and 1 g of water.

Pluronic L-61 refers to an ethylene oxide-propylene oxide block polymer, available from Wyandotte Chemicals Corporation.

Lubrol FSA also refers to an ethylene oxide-propylene oxide block polymer.

Freon R-11B is a trichlorofluoromethane propellant dar, available from DuPont.

Polyol A refers to polyoxypropylene (9) bis (4-hydroxyphenyl) propane.

Polyol B refers to polyoxyethylene (9) bis (4-hydroxyphenyl) propane.

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Polyol C refers to polyoxypropylene (6) bis (4-hydroxyphenyl) propane.

Polyol D refers to polyoxypropylene (4) bis (4-hydroxyphenyl) propane. "

Polyol E refers to polyoxypropylene (12) bis (4-hydroxyphenyl) propane.

Polyol F refers to polyoxyethylene (12) bis (4-hydroxyphenyl) propane.

Polyol G refers to polyoxypropylene (9) (2,3-dibromo-4-hydroxyphenyl) propane.

example 1

A foam-forming mass was created which comprised:

Rubinate M 100.0 L-5340 0.8 Solution a 1.4 Tris (betachloropropyl) phosphate 10.0 Plu-ronic L-61 4.0 Freon E-11B 18.0 Polyol A. 25.0 Polyol B 25.0

The foam produced from this mass had a density of. 2, 3 PCF and had the following physical properties:

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4.0 9 8 A 9/1 0 U 1

Weight retention 92.0%

Friability 27.0%

Example 2

A foam-forming mass was produced which comprised:

Rubxnate M. 100.0 L-5340 0.8 Solution a 1.4 Tris (betachloropropyl) phosphate 10.0 Pluronic L-61 4.0 Freon R-11B 18.0 Polyol A. 37.5 Poly oil B 12.5

The foam produced from this composition had a density of 2.2 PCF and had the following physical properties on:

Weight retention 91.0%

Friability 40.O%

Example 3

A foam-forming mass was created which comprised:

Rubinate M 100.0

L-5340 0.8

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Solution A 1.4

Tris (betachloropropyl) phosphate 10.0

Pluronic L-61 4.0

Freo R-11B 18.0

Polyol A 50.0

The foam produced from this mass had a density of 2.0 PCF and had the following physical properties on:

Weight retention 85.0%

Friability 40.0%

Example 4

A foam-forming mass was created which comprised:

Rubinate M 100.0 L-5340 0.8 Solution a 1.4 Tris (betachloropropyl) phosphate 10.0 Pluronic L-61 4.0 Freon R-11B 18.0 Polyol B " 50.0

The foam produced from this composition had a density of 2.1 PCF and had the following physical properties on:

Weight retention 93.5%

Friability 19.0%

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Example 5

A foam-forming mass was created which comprised:

Rubinate M 100.0 L-53 40 0.8 Solution a 1.4 Tris (betächlörpröpyi) phosphate 10.0 Pluronlc L- 61 4.0 Freon R-11B 18.0 Polyol C 50.0

The foam produced from this mass had the following physical properties:

Weight retention 87.0% Friability 46.0% Example 6

A foam-forming mass was created which comprised:

Rubinate M 100.0 Solution A. 1.4 L-5420 1.0 Tris (chloropropyl) phosphate 10.0 Freon R-11B 22.O Polyol D JO.O

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The foam produced from this mass had the following physical properties:

Weight retention 82.O%

Friability * 60.0%

Example 7

A foaming hatred was created that included:

Rubinate M 100.0

Solution A 1.4

L-5340 0.8

Lubrol FSA 4.O

Tris (chloroporpyl) phosphate 10.0

Freon R-11B, 20.0

Polyol E. 29.7

Polyol F 29.7

The foam produced from this mass had the following physical properties:

Weight retention 66.0 %

Friability 27.5 %

Example 8

A foam-forming mass was created which comprised:

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- 22 - Rubinate M 2423993 Solution a 100.0 L-5420 1.4 Tris (chloropropyl) phosphate 1.0 Freon R-11B 10.0 Polyol A. 22.0 Polyol G. 29.5 29.5

The foam generated from this hatred had the following physical properties on:

Weight retention 89.0%

Friability 36.0%

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Claims (7)

Claims 1. Foam-forming mass, which is an isocyanate, a Kataly satEor, "" a "TreTBmitteTT a surface half" € lves ~ MitteT and a polyol comprising, characterized ge ke η η ζ ei ch -NET that the polyol has the formula H (OR ¹ I 0- <O VR ^ <O> —O (R ¹ O) uptUt, in which ti an alkylidene group with 1 to 4 carbon atoms, a cycloalkylidene group with 5 to 6 carbons * #toffato «Än, oxygen, sulfur or a group the formula: -S-; C «O; Or S = O; M tarstelLt; K denotes halofen or tin «alkyl group having 1 to 3 carbon atoms; - 24 - 409849/1041 η is an integer from zero to four; R 'denotes an alkylene group of 2 to 4 carbon atoms or the radical -CH CH0-; and a and b represent integers that are at least one and where the sum is at least four. 2. Foam-forming composition according to claim 1, characterized in that g e k e η η draws that the sum of a and b is 4 to 12. 3. Foam-forming composition according to claim 1, characterized in that the sum of a and b is 5 to 10. 4. Foam-forming composition according to one of claims 1 to 3, characterized in that a mixture of polyols is used. 5. Composition according to claim 4, characterized in that in a polyol in the mixture R ^{1 represents} ethylene. 6. Composition according to claim 5, characterized in that in a second polyol in the mixture R ^{1 is} propylene. 7. Composition according to one of claims 1 to 6, characterized in that the amount of polyol is less than the amount required to react with 20% of the total isocyanate groups in the mass. A098A9 / 1041