CA2035252A1 - Mixtures of prepolymers containing urethane groups and diisocyanatotoluenes and their use - Google Patents
Mixtures of prepolymers containing urethane groups and diisocyanatotoluenes and their useInfo
- Publication number
- CA2035252A1 CA2035252A1 CA002035252A CA2035252A CA2035252A1 CA 2035252 A1 CA2035252 A1 CA 2035252A1 CA 002035252 A CA002035252 A CA 002035252A CA 2035252 A CA2035252 A CA 2035252A CA 2035252 A1 CA2035252 A1 CA 2035252A1
- Authority
- CA
- Canada
- Prior art keywords
- weight
- component
- mixture
- liquid mixture
- diisocyanatotoluene
- 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
Links
Classifications
-
- 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
- C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
- C08G18/72—Polyisocyanates or polyisothiocyanates
- C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
- C08G18/76—Polyisocyanates or polyisothiocyanates cyclic aromatic
- C08G18/7657—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings
- C08G18/7664—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings containing alkylene polyphenyl 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
- C08G18/08—Processes
- C08G18/10—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
-
- 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
- C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
-
- 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
- C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
- C08G18/72—Polyisocyanates or polyisothiocyanates
- C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
- C08G18/76—Polyisocyanates or polyisothiocyanates cyclic aromatic
- C08G18/7607—Compounds of C08G18/7614 and of C08G18/7657
-
- 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
- C08G2110/0008—Foam properties flexible
-
- 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
MIXTURES OF PREPOLYMERS CONTAINING URETHANE GROUPS
AND DIISOCYANATOTOLUENES AND THEIR USE
ABSTRACT OF THE DISCLOSURE
The present invention is directed to a liquid mixture, a method of preparing a foam with the liquid mixture and the resultant foam; said liquid mixture having a viscosity at 25°C
of 5 to 100 mPas and an NCO content of 35 to 47% by weight and comprising:
a) a liquid prepolymer containing urethane groups and having an NCO content of 5 to 30% by weight which is a reaction product of:
a1) a polyisocyanate or a polyisocyanate mixture is of the diphenylmethane series, and a2) a polyester polyol having a molecular weight of 500 to 10,000 in a substoichiometric quantity;
in admixture with b) a diisocyanatotoluene and/or component a1), in a ratio by weight of a) to b) of 1:20 to 20:1.
AND DIISOCYANATOTOLUENES AND THEIR USE
ABSTRACT OF THE DISCLOSURE
The present invention is directed to a liquid mixture, a method of preparing a foam with the liquid mixture and the resultant foam; said liquid mixture having a viscosity at 25°C
of 5 to 100 mPas and an NCO content of 35 to 47% by weight and comprising:
a) a liquid prepolymer containing urethane groups and having an NCO content of 5 to 30% by weight which is a reaction product of:
a1) a polyisocyanate or a polyisocyanate mixture is of the diphenylmethane series, and a2) a polyester polyol having a molecular weight of 500 to 10,000 in a substoichiometric quantity;
in admixture with b) a diisocyanatotoluene and/or component a1), in a ratio by weight of a) to b) of 1:20 to 20:1.
Description
Mo3528 LeA 27,398 MIXTURES OF PREPOLYMERS CONTAINING URETHANE GROUPS
AND DIISOCYANATOTOLUENES AND THEIR USE
BACKGROUND ~F THE INVENTION
Field of the Invention This invention relates to liquid mixtures comprising prepolymers containing urethane groups based on polyisocyanates or polyisocyanate mixtures of the diphenylmethane series and polyester polyols in admixture with diisocyanatotoluenes and/or polyisocyanates and to the use of these mixtures as isocyanate components in the production of flexible polyurethane foams, more part;cularly flexible molded foams.
Brief Description of the Prior Art: The advantageous use of prepolymers based on polyisocyanates and hydroxy (OH)-functional compounds such as polyols is known and described in detail in the literature: DE-PS 1,618,380, GB-PS
1,369,334, DE-OS 2,913,126, DE-OS 2,404,166, DE-AS 2,737,338, DE-AS 2,624,526, DE-OS 2,513,793, DE-OS 2,513,798, EP-A
0,010,850, EP-A 0,022,617 and EP-A 111,121. The above-mentioned prepolymers can be made up of various chemical components. For example, polyethers differing in functionality, molecular weight, starter molecule, ethylene oxide content or ethylene oxide/propylene oxide distribution can be used as the polyol component.
Generally, the quality of the prepolymers can be determined by the choice of the isocyanate and the polyol components. Illustratively, DE-A 3,818,769 shows that variation in the functionality of the polyether for the same or similar diphenylmethane diisocyanate base can produce a distinct improvement.
Typically, the prepolymers have higher viscosity and lower isocyanate (NCO) content than the corresponding, non-prepolymerized isocyanates. The higher viscosity can favorably affect metering accuracy of pumps employed in Le A 27 3~
... . .
:. :
S2~
AND DIISOCYANATOTOLUENES AND THEIR USE
BACKGROUND ~F THE INVENTION
Field of the Invention This invention relates to liquid mixtures comprising prepolymers containing urethane groups based on polyisocyanates or polyisocyanate mixtures of the diphenylmethane series and polyester polyols in admixture with diisocyanatotoluenes and/or polyisocyanates and to the use of these mixtures as isocyanate components in the production of flexible polyurethane foams, more part;cularly flexible molded foams.
Brief Description of the Prior Art: The advantageous use of prepolymers based on polyisocyanates and hydroxy (OH)-functional compounds such as polyols is known and described in detail in the literature: DE-PS 1,618,380, GB-PS
1,369,334, DE-OS 2,913,126, DE-OS 2,404,166, DE-AS 2,737,338, DE-AS 2,624,526, DE-OS 2,513,793, DE-OS 2,513,798, EP-A
0,010,850, EP-A 0,022,617 and EP-A 111,121. The above-mentioned prepolymers can be made up of various chemical components. For example, polyethers differing in functionality, molecular weight, starter molecule, ethylene oxide content or ethylene oxide/propylene oxide distribution can be used as the polyol component.
Generally, the quality of the prepolymers can be determined by the choice of the isocyanate and the polyol components. Illustratively, DE-A 3,818,769 shows that variation in the functionality of the polyether for the same or similar diphenylmethane diisocyanate base can produce a distinct improvement.
Typically, the prepolymers have higher viscosity and lower isocyanate (NCO) content than the corresponding, non-prepolymerized isocyanates. The higher viscosity can favorably affect metering accuracy of pumps employed in Le A 27 3~
... . .
:. :
S2~
processing the prepolymers. The lower NCO content can adversely affect properties such as hardness of foams prepared with the prepolymers.
As would be realized, it would be desirable to have prepolymers that have a higher viscosity and a high NCO content at the same time. By the present invention, there is provided l~quid mixtures containing prepolymers which combine high viscosity with a high NCO content.
SUMMARY OF THE INVENTION
In accordance with the foregoing, the present invention encompasses a liquid mixture having a viscosity at 25-C of 5 to 100 mPas and an NCO content of 35 to 47% by weight and comprising a) a liquid prepolymer containing urethane groups and having an NCO content of 5 to 30% by weight which is a reaction product of:
al) a polyisocyanate or a polyisocyanate mixture of the diphenylmethane series, and a2) a polyester polyol having a molecular weight of 500 to 10,000 in a substoichiometric quantity, in admixture with b) a diisocyanatotoluene and/or component al) in a ratio by weight of a) to b) of 1:20 to 20:1.
The invention further encompasses an improvement in the method of preparing foams and foams produced by reacting the liquid mixture of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The liquid mixtures of the invention are characterized in that they contain prepolymers which have, at once, high viscosities and high NCO content. Hence, one is able to overcome the prior art problem of compromising the des;rable prepolymer property of high viscosity for a high NCO content, or vice versa. .
The liquid prepolymer can be prepared by reacting a component al)~polyisocyanate or polyisocyanate mixtures of the Le A 27 398 .. . , .
: . :............. . .. , . . : .
: : ; .. . ~ : , .
:: - - . . ~ . , ::. : : .. , . . - -.- , . - . : :
~ J~ 2 diphenylmethane series and, in a substoichiometric quantity, with a component a2) polyester polyol having a molecular weight Of S00 to 10.000-The polyisocyanate component al) can be an aliphatic, cycloaliphatic, araliphatic or preferably an aromatic polyisocyanate, i.e., a polyisocyanate in which all of the isocyanate groups are aromatically bound. Examples of the aromatic polyisocyanate can include 2,4- and/or 2,6-diisocyanatotoluene; 2,2'-, 2,4'-, and/or 4,4'-diisocyanatodiphenylmethane, or a mixture of isomers or an isomeric mixture with a higher homolog of an isomer. A
technical mixture of 4,4'-, 2,4'- and up to 10% and preferably from < 5 % by weight 2,2'-diisocyanatodiphenyl methane or a mixture of an isomer or an isomeric mixture with a homolog of higher functionality, of the type formed in the phosgenation of an aniline formaldehyde condensate, is preferably used.
The compounds of component a2) contain ;socyanate-reactive groups and are typically polyesters having a molecular weight in the range from 500 to 10,000 and preferably in the range from 1,000 to 7,000 which normally contain at least two, preferably terminal, isocyanate-reactive groups. These isocyanate-reactive groups are alcoholic hydroxyl groups attached to primary or secondary carbon atoms. The molecular weights mentioned may be determined, for example, by vapor pressure osmometry.
The polyester polyol of component a2) is preferably a reaction product of a dicarboxylic acid or an anhydride with an excess of polyhydric alcohol having a molecular weight of 62 to 200. In a particularly preferred embodiment, the polyester polyol is a reaction product of adipic acid and/or terephthalic acid with diethylene glycol and/or glycerol. Accordingly, the polyester polyols known per se from polyurethane chemistry which correspond to the foregoing observations may be used as component a2). The polyester polyols may be produced, for example, from polybasic carboxylic acids, preferably aliphatic ~e A 27 398 ;
. ~, .
-- c f ~
~ JcjJ ~ ~ ~
dicarboxylic acids, containing 2 to 12 and preferably 4 to 8 carbon atoms in the alkylene radical and polyhydric alcohols, preferably diols. Examples of suitable polybasic carboxylic acids are aliphatic dicarboxylic acids~ such as glutaric acid, 5 pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid and preferably succinic and adipic acid, and aromatic dicarboxylic acids, such as phthalic acid and tereph~halic acid. Examples of polyhydric, more especially di- and trihydric, alcohols are ethylene 10 glycol, diethylene glycol, 1,2- and 1,3-propylene glycol, dipropylene glycol, decane-l,10-diol, glycerol, trimethylol propane and preferably butane-1,4-diol and hexane-1,6-diol.
Where polyhydric, particularly trihydric, alcohols are used for the production of the polyester polyols, their content is best 15 calculated in such a way that the functionality of ~he polyester polyols obtained is at most 6 and preferably 2 to 4.
Component b) can be a diisocyanatotoluene and/or a polyisocyanate of component al) in a ratio by weight of a) to b) of 1:20 to 20:1 and preferably 1:1. Technical mixtures of 20 2,4-diisocyanatotoluene with up to 45% and preferably 20 to 35 by weight 2,6-diisocyanatotoluene are preferably used as the diisocyanatotoluenes.
The equivalence ratio of the NCO groups of component al) to the OH groups of component a2) is 20:1 and preferably 1:5.
25 The liquid prepolymer has NCO content of 5 to 30% and preferably 15 to 25%.
The liquid mixtures have NCO content of 35 to 47% and preferably 35 to 42%. viscosityof the liquid mixture can range from 5 to 100 and preferably 20 to 40 ~p~s.
As mentioned above, the liquid mixtures of the prepolymers with the diisocyanatotoluenes and/or component al) may be used as the isocyanate components in the production of elastic, open-cell foams, preferably molded foams. The liquid mixtures according to the invention are processed to elastic, open-cell flexible foams by the reaction with:
Le A 27 398 .. ~ .. .. , ~ ~ . ....
: :~ . - ' . ` .
~ ~ , .. .
: - : :-- . . ~ . -. : ~. : ... . . , -.; . .
.,.,, . , ., - , ~, ,, . ~:-. :- :: ~- , -,.- :-2 ~ ~ 5 ~J ~ ~
1. compounds conta;ning at least two isocyanate-reactive hydrogen atoms and having a molecular weight in the range from 400 to lO,OOO, preferably from 1,000 to 6,000 and more preferably from 3,000 to 6,000. Compounds of this type are preferably compounds containing hydroxyl groups, more preferably compounds containing 2 to 6 and most preferably 2 to 4 hydroxyl groups. Example thereof can be polyethers or polyesters containing 2 to 6 and preferably 2 to 4 hydroxyl groups. Particularly preferred are polyethers of the type known per se for the production of homogeneous and cellular polyurethanes as described, for example, in DE-OS 2 832 253, pages 11 et seq. They preferably have an OH value of 28 to 56;
2. optionally compounds containing at least two isocyanate-reactive hydragen atoms and having a molecular weight in the range from 62 to 399. In this case, too, the compounds in question are compounds containing hydroxyl groups which serve as chain-extending agents or crosslinking agents.
These compounds generally contain 2 to 4 isocyanate-reactive hydrogen atoms. Examples of these compounds can be found in DE-OS 28 32 253, pages 10 et seq.;
3. water as a blowing agent in a quantity of l to 15 parts by weight per lOO parts by weight of component l.
4. optionally auxiliaries and additives, such as a) readily volatile organic substances as further blowing agents, b) reaction accelerators and reaction retarders known per se in typical quantities, c) surface-active additives, such as emulsifiers and foam stabilizers; cell regulators known per se, such as paraffins or fatty alcohols or dimethyl polysiloxanes; pigments or dyes and flameproofing agents known per se, for example tris-chloroethyl phosphate, tricresyl phosphate; stabilizers against the effects of aging and weathering; plasticizers;
fungistatic and bacteriostatic agents; and fillers, Le A 27 398 '' .
.
?~ ~j 2 such as barium sulfate, kieselguhr, carbon black or whiting.
These optional auxiliaries and additives are descr1bed, for example, in DE-OS 27 32 292, pages 21 et seq. Further examples of surface-active additives, foam stabilizers, cell regulators, reaction retarders, stabilizers, flameproofing agents, plasticizers, dyes, fillers and fungistatic and bacteriostatic agents may optionally be used in accordance with the invention. Information on their use and their mode of action can be found in Kunststoff-Handbuch, Vol. YII~ edited by Vieweg and Hochtlen, Carl-Hanser-Verlag, Munchen 1966, for example on pages 103 to 113.
The reaction components are preferably reacted by the one-shot process known per se, often using machines, for example of the type described in US-PS 2,764,565. Particulars of processing machines can be found in ~unststoff Handbuch, Vol. VII, edited by Vieweg and Hochtlen, Carl-Hanser-Verlag, Munchen 1966, for example on pages 121 to 205.
Foaming is preferably carried out in closed molds. To this end, the reaction components are introduced into a mold which may be made of metal, for example aluminum, or of plastic, for example epoxy resin. The resulting reaction mixture foams in the mold and forms the molding. According to the invention, foamable reaction mixture may be introduced into the mold in such a quantity that the foam formed just fills the mold. However, more foamable reaction mixture may be introduced into the mold than is necessary to fill the interior of the mold with foam. This particular technique is known as overcharging and is known, for example, from US-PSS 3,178,490 and 3,181,104.
The advantages of the mixtures according to the invention lie in the improvement of the physical properties of the foams produced with them, in the safety of processing which manifests in metering accuracy, and in the improvement of foam quality.
_e A 27 398 - . .
. - ~
hvsJ~2~2 The use of the mixtures according to the invention enables higher compression hardness to be obtained in the foams. This means that the processor of the foams does not have to use expensive filling ethers or additional crosslinking agents in order to obtain an improved foam hardness. In accordance with this invention, compression hardness can be improved (i.e.
page 9, table II ) .
The mixtures are distinguished by their high viscosity.
The high viscosity is advantageous in processing because metering accuracy of pumps is better at high viscosities.
Correct metering of the components is essential for modern high-quality foam production.
In addition, the high polarity of the polyester polyol component has an advantageous effect on the foam-forming reaction. An emulsifying effect on the likewise highly polar water improves reactivity and leads to stable foams. In addition, these foams are distinguished by a pleasant and elastic surface.
The invention is further illustrated by the following non-limiting examples.
EXAMPLES
Starting materials for foam production:
Prepolymer: 100 parts by weight(wt) of a polyester polyol prepared by reaction of ethylene glycol and adipic acid, OH value 55, were reacted while stirring with pure 4,4'-diphenylmethane diisocyanate to form a prepolymer having an NCO
content of 17X by weight.
Isocyanate: tolylene diisocyanate (80% by weight 2,4-isomer and 20% by weight 2,6-isomer) Polyether A: trifunctional ethylene oxide/propylene oxide polyether (OH value 30, ethylene oxide content 14% by weight) Polyether B: polyether A additionally modified with 20%
Le A 27 398 _ - ~ ' , ~ . ...
.~ - : . , 2~ 2 by weight styrene/acrylonitrile polymer Catalyst 1: triethylenediamine, 33% by weight in d;propylene glycol Catalyst 2: di-(2-dimethylaminoethyl)-methylam~ne Catalyst 3: diethanolamine Stabilizer: B 8629, polysiloxane, a product of Goldschmidt AG
The foam was produced as stated in the specification. The results are shown in Tables I and II:
Table I
Content Viscosity NC0 content (% by wt.) (mPas) at 25CC (% by wt.) Prepolymer - 3 48.3 Isocyanate 100 Prepolymer 15 13 43.6 Isocyanate 85 Prepolymer 20 22 42.0 Isocyanate 80 Prepolymer 45 Isocyanate 55 Le A 27 398 .
:
' :, .
g Table II
Example 1 Example 2 Polyether A 80% by wt. 80% by wt.
Polyether B 20 " 20 "
Water 3.2 n 3.2 "
Catalyst 1 0.5 ~ 0-5 "
Catalyst 2 0.06 ~ 0.06 "
Catalyst 3 1.2 n 1.2 ~
Stabilizer 0.5 " 0.5 "
G =.~
prepolvLr~er - 2 n ~
Isocyanate 100 " 80 "
Index* 100 100 Density (kg/m3), (as measured on the foam) 39 38 Compression hardness at 2.2 2.7 40% compression (kPa), as measured on the foam * The index is calculated in accordance with the following equation: Index = quotient of the number of NC0 groups divided by the number of NC0-reactive groups multiplied by 100.
The viscosities of the isocyanate and mixtures of the prepolymer with tolylene diisocyanate and the NC0 contents are shown in Table I.
The compression hardness of the foam produced using the prepolymer mixture according to the invention is 22% higher than that of a conventional foam (see Table II).
Le A 27 398 : : : , . . . .
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Although the invention has been described in detail in the foregoing for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variation can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims.
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As would be realized, it would be desirable to have prepolymers that have a higher viscosity and a high NCO content at the same time. By the present invention, there is provided l~quid mixtures containing prepolymers which combine high viscosity with a high NCO content.
SUMMARY OF THE INVENTION
In accordance with the foregoing, the present invention encompasses a liquid mixture having a viscosity at 25-C of 5 to 100 mPas and an NCO content of 35 to 47% by weight and comprising a) a liquid prepolymer containing urethane groups and having an NCO content of 5 to 30% by weight which is a reaction product of:
al) a polyisocyanate or a polyisocyanate mixture of the diphenylmethane series, and a2) a polyester polyol having a molecular weight of 500 to 10,000 in a substoichiometric quantity, in admixture with b) a diisocyanatotoluene and/or component al) in a ratio by weight of a) to b) of 1:20 to 20:1.
The invention further encompasses an improvement in the method of preparing foams and foams produced by reacting the liquid mixture of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The liquid mixtures of the invention are characterized in that they contain prepolymers which have, at once, high viscosities and high NCO content. Hence, one is able to overcome the prior art problem of compromising the des;rable prepolymer property of high viscosity for a high NCO content, or vice versa. .
The liquid prepolymer can be prepared by reacting a component al)~polyisocyanate or polyisocyanate mixtures of the Le A 27 398 .. . , .
: . :............. . .. , . . : .
: : ; .. . ~ : , .
:: - - . . ~ . , ::. : : .. , . . - -.- , . - . : :
~ J~ 2 diphenylmethane series and, in a substoichiometric quantity, with a component a2) polyester polyol having a molecular weight Of S00 to 10.000-The polyisocyanate component al) can be an aliphatic, cycloaliphatic, araliphatic or preferably an aromatic polyisocyanate, i.e., a polyisocyanate in which all of the isocyanate groups are aromatically bound. Examples of the aromatic polyisocyanate can include 2,4- and/or 2,6-diisocyanatotoluene; 2,2'-, 2,4'-, and/or 4,4'-diisocyanatodiphenylmethane, or a mixture of isomers or an isomeric mixture with a higher homolog of an isomer. A
technical mixture of 4,4'-, 2,4'- and up to 10% and preferably from < 5 % by weight 2,2'-diisocyanatodiphenyl methane or a mixture of an isomer or an isomeric mixture with a homolog of higher functionality, of the type formed in the phosgenation of an aniline formaldehyde condensate, is preferably used.
The compounds of component a2) contain ;socyanate-reactive groups and are typically polyesters having a molecular weight in the range from 500 to 10,000 and preferably in the range from 1,000 to 7,000 which normally contain at least two, preferably terminal, isocyanate-reactive groups. These isocyanate-reactive groups are alcoholic hydroxyl groups attached to primary or secondary carbon atoms. The molecular weights mentioned may be determined, for example, by vapor pressure osmometry.
The polyester polyol of component a2) is preferably a reaction product of a dicarboxylic acid or an anhydride with an excess of polyhydric alcohol having a molecular weight of 62 to 200. In a particularly preferred embodiment, the polyester polyol is a reaction product of adipic acid and/or terephthalic acid with diethylene glycol and/or glycerol. Accordingly, the polyester polyols known per se from polyurethane chemistry which correspond to the foregoing observations may be used as component a2). The polyester polyols may be produced, for example, from polybasic carboxylic acids, preferably aliphatic ~e A 27 398 ;
. ~, .
-- c f ~
~ JcjJ ~ ~ ~
dicarboxylic acids, containing 2 to 12 and preferably 4 to 8 carbon atoms in the alkylene radical and polyhydric alcohols, preferably diols. Examples of suitable polybasic carboxylic acids are aliphatic dicarboxylic acids~ such as glutaric acid, 5 pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid and preferably succinic and adipic acid, and aromatic dicarboxylic acids, such as phthalic acid and tereph~halic acid. Examples of polyhydric, more especially di- and trihydric, alcohols are ethylene 10 glycol, diethylene glycol, 1,2- and 1,3-propylene glycol, dipropylene glycol, decane-l,10-diol, glycerol, trimethylol propane and preferably butane-1,4-diol and hexane-1,6-diol.
Where polyhydric, particularly trihydric, alcohols are used for the production of the polyester polyols, their content is best 15 calculated in such a way that the functionality of ~he polyester polyols obtained is at most 6 and preferably 2 to 4.
Component b) can be a diisocyanatotoluene and/or a polyisocyanate of component al) in a ratio by weight of a) to b) of 1:20 to 20:1 and preferably 1:1. Technical mixtures of 20 2,4-diisocyanatotoluene with up to 45% and preferably 20 to 35 by weight 2,6-diisocyanatotoluene are preferably used as the diisocyanatotoluenes.
The equivalence ratio of the NCO groups of component al) to the OH groups of component a2) is 20:1 and preferably 1:5.
25 The liquid prepolymer has NCO content of 5 to 30% and preferably 15 to 25%.
The liquid mixtures have NCO content of 35 to 47% and preferably 35 to 42%. viscosityof the liquid mixture can range from 5 to 100 and preferably 20 to 40 ~p~s.
As mentioned above, the liquid mixtures of the prepolymers with the diisocyanatotoluenes and/or component al) may be used as the isocyanate components in the production of elastic, open-cell foams, preferably molded foams. The liquid mixtures according to the invention are processed to elastic, open-cell flexible foams by the reaction with:
Le A 27 398 .. ~ .. .. , ~ ~ . ....
: :~ . - ' . ` .
~ ~ , .. .
: - : :-- . . ~ . -. : ~. : ... . . , -.; . .
.,.,, . , ., - , ~, ,, . ~:-. :- :: ~- , -,.- :-2 ~ ~ 5 ~J ~ ~
1. compounds conta;ning at least two isocyanate-reactive hydrogen atoms and having a molecular weight in the range from 400 to lO,OOO, preferably from 1,000 to 6,000 and more preferably from 3,000 to 6,000. Compounds of this type are preferably compounds containing hydroxyl groups, more preferably compounds containing 2 to 6 and most preferably 2 to 4 hydroxyl groups. Example thereof can be polyethers or polyesters containing 2 to 6 and preferably 2 to 4 hydroxyl groups. Particularly preferred are polyethers of the type known per se for the production of homogeneous and cellular polyurethanes as described, for example, in DE-OS 2 832 253, pages 11 et seq. They preferably have an OH value of 28 to 56;
2. optionally compounds containing at least two isocyanate-reactive hydragen atoms and having a molecular weight in the range from 62 to 399. In this case, too, the compounds in question are compounds containing hydroxyl groups which serve as chain-extending agents or crosslinking agents.
These compounds generally contain 2 to 4 isocyanate-reactive hydrogen atoms. Examples of these compounds can be found in DE-OS 28 32 253, pages 10 et seq.;
3. water as a blowing agent in a quantity of l to 15 parts by weight per lOO parts by weight of component l.
4. optionally auxiliaries and additives, such as a) readily volatile organic substances as further blowing agents, b) reaction accelerators and reaction retarders known per se in typical quantities, c) surface-active additives, such as emulsifiers and foam stabilizers; cell regulators known per se, such as paraffins or fatty alcohols or dimethyl polysiloxanes; pigments or dyes and flameproofing agents known per se, for example tris-chloroethyl phosphate, tricresyl phosphate; stabilizers against the effects of aging and weathering; plasticizers;
fungistatic and bacteriostatic agents; and fillers, Le A 27 398 '' .
.
?~ ~j 2 such as barium sulfate, kieselguhr, carbon black or whiting.
These optional auxiliaries and additives are descr1bed, for example, in DE-OS 27 32 292, pages 21 et seq. Further examples of surface-active additives, foam stabilizers, cell regulators, reaction retarders, stabilizers, flameproofing agents, plasticizers, dyes, fillers and fungistatic and bacteriostatic agents may optionally be used in accordance with the invention. Information on their use and their mode of action can be found in Kunststoff-Handbuch, Vol. YII~ edited by Vieweg and Hochtlen, Carl-Hanser-Verlag, Munchen 1966, for example on pages 103 to 113.
The reaction components are preferably reacted by the one-shot process known per se, often using machines, for example of the type described in US-PS 2,764,565. Particulars of processing machines can be found in ~unststoff Handbuch, Vol. VII, edited by Vieweg and Hochtlen, Carl-Hanser-Verlag, Munchen 1966, for example on pages 121 to 205.
Foaming is preferably carried out in closed molds. To this end, the reaction components are introduced into a mold which may be made of metal, for example aluminum, or of plastic, for example epoxy resin. The resulting reaction mixture foams in the mold and forms the molding. According to the invention, foamable reaction mixture may be introduced into the mold in such a quantity that the foam formed just fills the mold. However, more foamable reaction mixture may be introduced into the mold than is necessary to fill the interior of the mold with foam. This particular technique is known as overcharging and is known, for example, from US-PSS 3,178,490 and 3,181,104.
The advantages of the mixtures according to the invention lie in the improvement of the physical properties of the foams produced with them, in the safety of processing which manifests in metering accuracy, and in the improvement of foam quality.
_e A 27 398 - . .
. - ~
hvsJ~2~2 The use of the mixtures according to the invention enables higher compression hardness to be obtained in the foams. This means that the processor of the foams does not have to use expensive filling ethers or additional crosslinking agents in order to obtain an improved foam hardness. In accordance with this invention, compression hardness can be improved (i.e.
page 9, table II ) .
The mixtures are distinguished by their high viscosity.
The high viscosity is advantageous in processing because metering accuracy of pumps is better at high viscosities.
Correct metering of the components is essential for modern high-quality foam production.
In addition, the high polarity of the polyester polyol component has an advantageous effect on the foam-forming reaction. An emulsifying effect on the likewise highly polar water improves reactivity and leads to stable foams. In addition, these foams are distinguished by a pleasant and elastic surface.
The invention is further illustrated by the following non-limiting examples.
EXAMPLES
Starting materials for foam production:
Prepolymer: 100 parts by weight(wt) of a polyester polyol prepared by reaction of ethylene glycol and adipic acid, OH value 55, were reacted while stirring with pure 4,4'-diphenylmethane diisocyanate to form a prepolymer having an NCO
content of 17X by weight.
Isocyanate: tolylene diisocyanate (80% by weight 2,4-isomer and 20% by weight 2,6-isomer) Polyether A: trifunctional ethylene oxide/propylene oxide polyether (OH value 30, ethylene oxide content 14% by weight) Polyether B: polyether A additionally modified with 20%
Le A 27 398 _ - ~ ' , ~ . ...
.~ - : . , 2~ 2 by weight styrene/acrylonitrile polymer Catalyst 1: triethylenediamine, 33% by weight in d;propylene glycol Catalyst 2: di-(2-dimethylaminoethyl)-methylam~ne Catalyst 3: diethanolamine Stabilizer: B 8629, polysiloxane, a product of Goldschmidt AG
The foam was produced as stated in the specification. The results are shown in Tables I and II:
Table I
Content Viscosity NC0 content (% by wt.) (mPas) at 25CC (% by wt.) Prepolymer - 3 48.3 Isocyanate 100 Prepolymer 15 13 43.6 Isocyanate 85 Prepolymer 20 22 42.0 Isocyanate 80 Prepolymer 45 Isocyanate 55 Le A 27 398 .
:
' :, .
g Table II
Example 1 Example 2 Polyether A 80% by wt. 80% by wt.
Polyether B 20 " 20 "
Water 3.2 n 3.2 "
Catalyst 1 0.5 ~ 0-5 "
Catalyst 2 0.06 ~ 0.06 "
Catalyst 3 1.2 n 1.2 ~
Stabilizer 0.5 " 0.5 "
G =.~
prepolvLr~er - 2 n ~
Isocyanate 100 " 80 "
Index* 100 100 Density (kg/m3), (as measured on the foam) 39 38 Compression hardness at 2.2 2.7 40% compression (kPa), as measured on the foam * The index is calculated in accordance with the following equation: Index = quotient of the number of NC0 groups divided by the number of NC0-reactive groups multiplied by 100.
The viscosities of the isocyanate and mixtures of the prepolymer with tolylene diisocyanate and the NC0 contents are shown in Table I.
The compression hardness of the foam produced using the prepolymer mixture according to the invention is 22% higher than that of a conventional foam (see Table II).
Le A 27 398 : : : , . . . .
, ~, . -., . ., . -.: ~
~ ~J ~ ~ 2 ~3 ~
Although the invention has been described in detail in the foregoing for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variation can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims.
~e ~ 27 398 .:, .: . .
. - .
;..:
... ~ . . . . - .
r. ~ . . .
~, ' ., ~
Claims (8)
1. A liquid mixture having a viscosity at 25°C of 5 to 100 mPas and an NCO content of 35 to 47% by weight and comprising a) a liquid prepolymer containing urethane groups and having an NCO content of 5 to 30% by weight which is a reaction product of:
a1) a polyisocyanate or a polyisocyanate mixture of the diphenylmethane series, and a2) a polyester polyol having a molecular weight of 500 to 10,000, in a substoichiometric quantity;
in admixture with b) a diisocyanatotoluene and/or component a1), in a ratio by weight of a) to b) of 1:20 to 20:1.
a1) a polyisocyanate or a polyisocyanate mixture of the diphenylmethane series, and a2) a polyester polyol having a molecular weight of 500 to 10,000, in a substoichiometric quantity;
in admixture with b) a diisocyanatotoluene and/or component a1), in a ratio by weight of a) to b) of 1:20 to 20:1.
2. A liquid mixture as recited in Claim 1 wherein component a2) is a reaction product of a dicarboxylic acid or an anhydride with an excess of a polyhydric alcohol having molecular weights of 62 to 200.
3. A liquid mixture as recited in Claim 1 containing a reaction product of adipic acid and/or terephthalic acid with diethylene glycol and/or glycerol as component a2).
4. A liquid mixture as recited in Claim 1 containing a technical mixture of 2,4-diisocyanatotoluene with up to 45% by weight 2,6-diisocyanatotoluene as the diisocyanatotoluene component.
5. A liquid mixture as recited in Claim 1 containing a technical mixture of 4,4'-, 2,4'- and up to 10% by weight 2,2'-diisocyanatodiphenyl methane, or a mixture of isomers or an isomeric mixture with a homolog of higher functionality, of the type formed in the phosgenation of an aniline/formaldehyde condensate, as component a1)
6. A liquid mixture as recited in Claim 1 containing a prepolymer in which the equivalence ratio of the NCO groups of component a1) to the OH groups of component a2) is of 20:1 to 1:5.
7. A method of preparing an elastic, open-cell flexible foam, by reacting a liquid mixture having a viscosity at 25°C
of 5 to 100 mPas and an NCO content of 35 to 47% by weight and comprising a) a liquid prepolymer containing urethane groups and having an NCO content of 5 to 30% by weight which is a reaction product of:
a1) a polyisocyanate of the diphenylmethane series and, a2) a polyester polyol having a molecular weight of 500 to 10,000 in a substoichiometric quantity;
in admixture with b) a diisocyanatotoluene and/or component a1), in a ratio by weight of a) to b) of 1:20 to 20:1..
of 5 to 100 mPas and an NCO content of 35 to 47% by weight and comprising a) a liquid prepolymer containing urethane groups and having an NCO content of 5 to 30% by weight which is a reaction product of:
a1) a polyisocyanate of the diphenylmethane series and, a2) a polyester polyol having a molecular weight of 500 to 10,000 in a substoichiometric quantity;
in admixture with b) a diisocyanatotoluene and/or component a1), in a ratio by weight of a) to b) of 1:20 to 20:1..
8. An elastic, open-cell flexible foam which is prepared by the method of Claim 7.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP4006248.1 | 1990-02-28 | ||
| DE4006248A DE4006248A1 (en) | 1990-02-28 | 1990-02-28 | MIXTURES OF PRAEPOLYMERS AND DIISOCYANATOTOLUOLES CONTAINING URETHANE GROUPS AND THEIR USE |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2035252A1 true CA2035252A1 (en) | 1991-08-29 |
Family
ID=6401117
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002035252A Abandoned CA2035252A1 (en) | 1990-02-28 | 1991-01-30 | Mixtures of prepolymers containing urethane groups and diisocyanatotoluenes and their use |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0446468A1 (en) |
| JP (1) | JPH04218520A (en) |
| CA (1) | CA2035252A1 (en) |
| DE (1) | DE4006248A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5900441A (en) * | 1995-11-30 | 1999-05-04 | Imperial Chemical Industries Plc | Process for preparing a flexible polyurethane foam |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5436277A (en) * | 1994-07-28 | 1995-07-25 | Basf Corporation | Polyisocyanate compositions for the preparation of flexible polyurethane foams |
| US5674920A (en) * | 1994-12-08 | 1997-10-07 | Mitsui Toatsu Chemicals, Inc. | Flexible high resilience polyurethane foam |
| WO1996032431A1 (en) * | 1995-04-13 | 1996-10-17 | Marc Rolf Billeter | Low-viscosity polyurethane prepolymer |
| DE19700014A1 (en) * | 1997-01-02 | 1998-07-09 | Henkel Kgaa | Low-monomer PU prepolymer |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1369334A (en) * | 1973-06-05 | 1974-10-02 | Ici Ltd | Liquid isocyanate compositions |
| JPH0699535B2 (en) * | 1986-01-31 | 1994-12-07 | 日本ポリウレタン工業株式会社 | Polyurethane foam manufacturing method |
| DE3818769A1 (en) * | 1988-06-02 | 1989-12-07 | Bayer Ag | LIQUID POLYISOCYANATE MIXTURES, A METHOD FOR THE PRODUCTION THEREOF AND THEIR USE FOR THE PRODUCTION OF POLYURETHANE SOFT FOAMS |
-
1990
- 1990-02-28 DE DE4006248A patent/DE4006248A1/en not_active Withdrawn
- 1990-12-19 EP EP90124679A patent/EP0446468A1/en not_active Withdrawn
-
1991
- 1991-01-30 CA CA002035252A patent/CA2035252A1/en not_active Abandoned
- 1991-02-26 JP JP3053083A patent/JPH04218520A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5900441A (en) * | 1995-11-30 | 1999-05-04 | Imperial Chemical Industries Plc | Process for preparing a flexible polyurethane foam |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0446468A1 (en) | 1991-09-18 |
| JPH04218520A (en) | 1992-08-10 |
| DE4006248A1 (en) | 1991-08-29 |
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