CA1042146A - Process for reclaiming flexible polyurethane foam - Google Patents
Process for reclaiming flexible polyurethane foamInfo
- Publication number
- CA1042146A CA1042146A CA223,810A CA223810A CA1042146A CA 1042146 A CA1042146 A CA 1042146A CA 223810 A CA223810 A CA 223810A CA 1042146 A CA1042146 A CA 1042146A
- Authority
- CA
- Canada
- Prior art keywords
- foam
- scrap
- weight
- flexible
- aliphatic diol
- 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.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J11/00—Recovery or working-up of waste materials
- C08J11/04—Recovery or working-up of waste materials of polymers
- C08J11/10—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation
- C08J11/18—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material
- C08J11/22—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material by treatment with organic oxygen-containing compounds
- C08J11/24—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material by treatment with organic oxygen-containing compounds containing hydroxyl groups
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2375/00—Characterised by the use of polyureas or polyurethanes; Derivatives of such polymers
- C08J2375/04—Polyurethanes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/62—Plastics recycling; Rubber recycling
Abstract
NOVEL PROCESS
ABSTRACT OF THE DISCLOSURE
A process is described for converting scrap flexible polyurethane foam, derived from a polyether polyol, to a homogeneous mixture of polyols which can be used, alone or as a blend with other polyols, in the preparation of polyurethane foams. The process comprises heating the scrap foam with not more than its own weight of an aliphatic diol which has at least one alkyl substituent in the alkylene chain, and which optionally contains an oxygen atom in the alkylene chain. The scrap flexible foam can contain up to about 75 percent of scrap rigid or semi-flexible foam, if desired.
ABSTRACT OF THE DISCLOSURE
A process is described for converting scrap flexible polyurethane foam, derived from a polyether polyol, to a homogeneous mixture of polyols which can be used, alone or as a blend with other polyols, in the preparation of polyurethane foams. The process comprises heating the scrap foam with not more than its own weight of an aliphatic diol which has at least one alkyl substituent in the alkylene chain, and which optionally contains an oxygen atom in the alkylene chain. The scrap flexible foam can contain up to about 75 percent of scrap rigid or semi-flexible foam, if desired.
Description
BACKGROUND OF THE ~ N'VENTION
1. Field of the ~nvention This invention relates to the conversion of scrap polyurethane to useful polyols and is more particularly concerned with a process for the conversion of scrap flexible polyurethane foam, derived from a polyether polyol, to polyols which are reusable in the preparation of cellular polyurethanes.
1. Field of the ~nvention This invention relates to the conversion of scrap polyurethane to useful polyols and is more particularly concerned with a process for the conversion of scrap flexible polyurethane foam, derived from a polyether polyol, to polyols which are reusable in the preparation of cellular polyurethanes.
2. DescriPtion of the Prior Art The amount of scrap polyurethane foam which is being ~~ generated as trim, dust and the like from foam cutting operations, is a problem of increasing concern. The disposal thereof in solid waste form represents an environmental pollution problem as well as an economic L5 one. The racGvely and reuOe of sc.3p r gid ~olyu-eth_ne foam has recently become possible through the process described in U. S. Patent 3,738,946. The latter process involves heating the scrap foam with a mixture of aliphatic diol and a minor amount of dialkanolamine to produce a homogeneous polyol mixture capable of use, in its entirety as a polyol component in the production of new polyurethane foam. The prior attempts to solve the problem of recovery of scrap foam are discussed in some detail in the above cited patent and will not be reviewed here.
Unfortunately the process of the above cited patent, which is entirely satisfactory for rigid foams, cannot be applied successfully to the recovery of the major class of flexible foams, namely, those derived from a polyether polyol.
Thus, the process of the above patent, when employed with scrap from flexible, polyether-based foams, gives a product -2- ~
which separates into two layers, one of which is a polyol and the other appears to be a polyamine. The latter requires to be separated from the former and is not useful in the preparation of further polyurethane foams, although it has uses as a curing agent for epoxides and the like.
Substantially the same result is reported in U. S.
Patent 3,632 530 which describes the treatment of scrap flexible polyether-based polyurethane foam by heating in the presence of an aliphatic glycol and, optionally, a tertiary amine. The product separates into two layers one of which is polyol and the other is said to be polyamine.
; The latter is separated and shown to be useful as an amine curative for epoxy resins and for isocyanate-terminated prepolymers. As is evident from Example 9 of the above cited patent, there is no such problem with a polyester-based flexible foam. The latter gives rise to a homo-- geneous product which shows no tendency to separate into ' two layers.
~- Unfortunately, however, the bulk of the flexible foams currently produced commercially are derived from polyether polyols, and scrap from such foams has not so far been converted successfully to a homogeneous product which is , -usable in its entirety as a polyol cbmponent for the pre-~aration of new polyurethane foam.
We have now found that, contrary to previously reported experience, it i9 possible, by careful choice of reactants, and of proportions thereof, and of reaction conditions, to convert scrap, polyether-based flexible polyurethane foam into a homogeneous mixture of polyols, which mixture does not separate into different components but can be used in 3_ ~ ~?
' ' ~ ' . .
, 3064 4~j its entirety as part, or the whole, of the polyol component employed in the preparation of new polyurethane foam.
SUMMARY OF THE INVENTION
The invention comprises a process of converting scrap flexible polyurethane foam, which has been derived from a polyether polyol, to a homogeneous mixture of polyols, which process comprises heating, at a temperature in the range of 180C to 250C, a mixture of (a) said scrap flexible polyurethane foam, preferably in a comminuted form, and 10 (b) an aliphatic diol having the formula HO -A -OH wherein A is selected from the class consisting of an alkylene radical from 2 to 6 carbon atoms, inclusive, and an alkylene radical from 2 to 6 carbon atoms wherein the chain thereof is interrupted by an oxygen atom, both of which alkylene radicals carry at least one lower-alkyl substituent on a carbon atom in the chain thereof, said di.ol being present in an amount by weight which does not exceed the total weight of said scrap foam.
The invention also comprises the polyol recovered in accordance with the above process.
The recovered polyol is useful, either alone or in admixture with virgin polyol, in the preparation of new polyurethane foam and, more particularly, in the preparation l -of new rigid polyurethane foam.
DETAILED DESCRIPTION OF THE INV~NTION
The term "alkylene radical from 2 to 6 carbon atoms, ` inclusive" means (CH8)n wherein n is an integer from 2 to 6, such as ethylene, propylene, butylene, pentylene, .
- hexylene. The term ~alkylene radical from 2 to 6 carbon-atoms, inclusive, wherein the chain thereof is interrupted ;. ~ .
- ' ' ' " ~ ' ' `
-- ...
by an oxygen atom" means a radical of the formula (CHa)X 0 - (CH2)y wherein x and y are each integers and wherein the sum of x ~ y is a whole number from 2 to 6.
The term "lower-alkyl" means alkyl from l to 6 carbon atoms, inclusive, such as methyl, ethyl, propyl, butyl~
pentyl, hexyl and isomeric forms thereof.
It will be apparent from the above definitions that the aliphatic diols employed in the process of the invention are those in which the alkylene group separating the two hydroxyl groups must be branched, i.e. there is a lower-alkyl - group present as a substituent on at least one of the carbon atoms of the alkylene chain. In addition to this alkyl substituent, there can, optionally, be an oxygen atom (i.e. an ether linkage) in the alkylene chain separating the two hydroxyl group.s~ Illustrative of aliphatic diols which meet the above requirements are 1,2-propylene glycol~
- 1,2-butanediol, 1,2-hexanediol, di(l~2-propylene glycol), ~ di(L,2-butylene glycol), 3-methylpentane-1,5-diol, 2~2-dimethyl-1,3-propanediol, 1,2-octanediol, and mixtures of two or more of any of these diols.
It is to be noted that certain of .he above glycols have been suggested previously as media in which to carry out the heat degradation of scrap flexible foam, see U. S. 3~632~530O However, the results reported in that patent with these diols, and a series of other closely related diols, always show the production of a product which separates into two layers, one of which constitutes polyol and the other amine. Although it is di~closed ln general terms by the reference that proportions of scrap ; 30 foam to glycol as high as equal amounts by weight can be -:' -4tj employed, the actual examples all use amounts of glycol which are considerably in excess, by weight, of the amount of scrap foam.
In contrast, we have found that, in the case of certain glycols only, namely, those in which the alkylene chain separating the hydroxyl groups is branched, it is possible to obtain an entirely different result to that hitherto described, provided that the proportion of scrap foam introduced into the admixture with the glycol is markedly increased over the proportion hitherto employed in the artO
Thus, by employing a glycol which meets the definition set forth above, and, further, by substantially increasing the proportion of scrap flexible polyether polyol-based foam to a minimum of at least an equal amount by weight based on glycol, and preferably in substantial excess of this amount, it has been found~ very surprisingly, that it lS
possible to convert said scrap foam to a homogeneous mixture of polyols. That is to say, the product shows no tendency to separate into two layers, as in the case of the prior art, and shows no indication of the presence of amine therein. Further,the entire product, rather than a minor proportion thereof, can be used as the polyol component, or as a part thereof, in the preparation of virgin poly-urethane foam.
As will be appreciated by one skilled in the art, this - is a highly advantageous and clearly unexpected finding particularly in view of the concentrated search which has been made by the polyurethane foam industry in recent years to find a commercially feasible and economic manner in which to recover scrap from flexible foam.
4~
In carrying out the process of the invention, the scrap flexible foam is advantageously chopped or ground to particles of relatively small size in order to reduce the volume of the scrap and to assist in reducing the time necessary for the reaction to take place~ The scrap foam and the appropriate diol defined above are then brought together in a single operation, if desired, and the resulting mixture is heated to a temperature in the range of about 180~C to about 250C, advantageously with agitation. Alternatively and preferably, the diol is heated to a temperature in the above range and the comminuted scrap foam is added thereto in increments with agitation.
As set forth above, the proportions in which the scrap foam and the aliphatic diol are employed in the process of - the invention are such that the amount of scrap foam by weight is at least equal to the amount by weight of aliphatic diol. Preferably the scrap foam is employed in a proportion corresponding to from about 1.5 times to about } 20 2 times the amount by weight of diol which is employed~
Once the admixture of scrap foam and aliphatic diol has been completed, preferably with agitation, the mixture is maintained at a temperature within the above range at least until all the scrap foam has dissolved and a homogeneous solution has been obtained. The end point of the reaction, namely, the point at which degradation of the scrap to a - useful polyol has been completed9 can be detected by routine techniques, for example, by infrared spectroscopic analysis, or by observing the rate of change of viscosity.
In general, the period of heating necessary to recover the 4~
scrap foam as polyol will range from about 2 hours to about 12 hours depending upon thelnature of the scrap polyurethane foam and diol which are employed. The most desirable reaction time for any particular combination of scrap foam and diol can be determined by a process of trial and error.
When the degradation of scrap foam is complete, as determined by routine analytical tests such as those described above, the reaction mixture is cooled, or allowed to cool, to room temperature. Depending upon the origin of the scrap foam it may be necessary to remove small quantities of particulate matter (e.g. fibers, non-polyurethane dust, laminate foil and the like) from the product by filtration or like techniques.
Subject to the necessity for such treatment the product derived above is ready, without any further modification, for use as the polyol component in the preparation of new polyurethane foam.
The product generally has an hydroxyl equivalent w~ight in the range of about 65 to about 120 and is accordingly preferably used in the preparation of rigid polyurethane foams or for any other purpose, e.g. as a minor component in the preparation of polyisocyanurate foams, for which polyols having equivalent weights within this range are normally used. If desired, the polyol mixture obtained by the process of the invention can be blended with virgin polyol prior to conversion to polyurethane and the like foams.
Alternatively, the hydroxyl equivalent weight of the polyol mixture obtained by the process of the invention can - be modified, i.e. increased, if desired, by reacting the recovered polyol with an alkylene oxide such as ethylene -- --104~1~5 oxide, propylene oxide and the like. The alko~ylation can be carried out by processes well-recognized in the art optionally in the presence of a basic catalyst such as potassium hydroxide, sodium hydroxide, and the like.
It has also been found surprisingly that substantial amounts of scrap foam derived from semi-rigid (also some-times known as semi-fle~ible) and/or rigid polyurethane or polyisocyanurate foams can be combined with the scrap flexible, polyether-based foams employed in the process of the invention without detracting from the overall result, - i.e. the production of a homogeneous mixture of polyols suitable for re-use in the preparation of polyurethane and like foams. Thus, it has been found that quantities of .~ . .
- scrap semi-rigid and/or rigid polyurethane or polyisocyanurate foam. Up to ahol~t 75 percent by weight, based on the scrap flexible polyether based foam, can be incorporated into the `- reaction mixture employed in the process of the invention.
Preferably, the various types of scrap foam are pre-blended before being added to the aliphatic diol, but the different types of scrap foam can be added separately to the aliphatic diol if desired.
When the flexible foam is subjected to the process of the invention in combination with scrap from other types of foam as discussed above, it is necessary that the total amount of scrap be such that the proportion of total scrap foam to aliphatic diol be always within the limits discussed above.
It is pertinent to note that, where the scrap flexible foam is subjected to the process of the invention in combin-ation with substantial quantities of scrap from the other _g_ sources described above, said scrap fle~ible foam can be present in the reaction mixture in an amount which represents less than an equal amount by weight compared to the aliphatic diol present in said reaction mixture.
Yet, provided that the total weight of flexible and other types of scrap foam present in the reaction is still at least equal by weight to the amount of aliphatic diol present therein, the overall desired result will still be obtained, i.e. the reaction product will be a homogeneous mi~ture of polyols. This finding is clearly contrary to the result which would be achieved were the scrap flexible foam to be employed alone in the same proportion by weight.
The viscosity of the reaction product obtained in ; accordance with the process of the invention is largely governed by the particular diol and scrap foam used and by the proportions in which they are used in the range set forth above. Advantageously, the viscosity of the , reaction product is within the range of about 300 centi-stokes to about 4,500 centistokes measured at 25C. A
viscosity in this range can be attained readily in the case of any particular diol and scrap polyurethane by a process of trial and error.
While any of the branched chain aliphatic diols falling within the definitions given above can be used in the process of the invention, a particularly preferred diol is 1,2-propylene glycol. It is to be noted in this regard that closely related aliphatic diols such as - ethylene glycol, diethylene glycol and butane-1,4-diol~
which differ only from the diols employed in the process of the invention by the absence of branching in the alkylene ..
~(~4~1~6 chain, do not give rise to a homogeneous mixture of polyols when employed under exactly the same conditions. Thus, the straight chain aliphatic diols such as those enumerated above, when heated with scrap flexible polyether-based foam 5 at the temperatures and in the proportions corresponding to those employed in the process of the invention, give rise to products which separate into two layers of different character, in contrast to the homogeneous mixturesobtained in accordance with the invention.
As will be obvious to one skilled in the art, the process of the invention can, if desired, be operated on a continuous basis. For example, the scrap foam and the aliphatic diol can be fed in separate streams, or after preblending if desired, to a continuous tube reactor in which the reactants are agitated and subjected to a temperature within the range set forth above. The residence time, or hold up time, in the reactor is adjusted so that the conversion to homogeneous polyol is effected in a single pass through the reactor. Alternatively, the reaction mixture can be continuously recycled through the reactor a plurality of times until the total residence `, time in the reactor is such as to accomplish the desired conversion. In a further alternative mode of operation on a continuous basis, the preliminary step of comminuting the scrap foam can be omitted and the scrap foam can be fed to a continuous reactor which is provided with means for crushing or comminuting the scrap foam in contact with the aliphatic diol preferably at a temperature within the ; range set forth above. Other modes of operation on a continuous basis will be readily apparent to one skilled in 14~
the art.
The following examples describe the manner and pro-cess of making and using the invention and set forth the best mode contemplated by the inventors of carrying out the invention but are not to be construed as limiting.
~xamDle 1 The scrap foam employed as starting material in the process described in this Example was obtained from a flexible foam which had been prepared using the following reactantS in the proportions (parts by weight) set forth below.
Toluene diisocyanate (80/20) u 49 parts Propoxylated glycerol * : 100 parts (eq. wt. = 1000; LG-56, Union Carbide) Stannous octoate - : 0.22 part N-ethylmorpholine u 0.25 part Triethylenediamine ~ 0 3 part Surfactant (L-520) . 1.0 parts Water u 4,0 parts ~he foam was prepared by thoroughly admixing all the components except the isocyanate and then adding the latter to the preblend of the other components and subjecting the resulting mixture to high speed mechanical stirring for 10 seconds. The resulting foam was cured at 25C for 7 days.
A batch ~25 9.) of scrap from the above foam was comminuted in a Wiley laboratory mill and added in incre-ments, over a period of 2 hour~ and 50 minutes, to 25 9.
of 1,2-propylene glycol maintained at 200C to 225C with . .
stirring. After the addition was complete, the mixture was heated with agitation for a further 6 hours ~approx.) until - ~ ~Trade Ma~ks 4~
a clear homogeneous solution was obtained. The resulting product was allowed to cool to room temperature (circa 20VC) and was found to remain a homogeneous liquid even after standing for several weeks. The product (48 g.) was dark brown and mobile, and had a viscosity of 407 centistokes at 20C and a hydroxyl equivalent weight of 81.5.
Example 2 A second batch of 40 g. of scrap from the flexible foam described in Example 1 was comminuted and added in 10 increments over a period of 4 hours and 25 minutes to 25 g.
of propylene glycol maintained at 200 to 234C with agitation.
When the addition was complete, the mixture was maintained for a further 6.5 hours within the same temperature range - with agitation. At the end of this time, the mixture was allowed to cool to room temperature (20C) to yield 60.6 g.
of a brown homogeneous mobile liquid which had a viscosity of 607 centistokes at 20C and a hydroxyl equivalent weight -- of 101.
Example 3 ` 20 This example illustrates the different result obtained using an aliphatic glycol other than those called for by the process of the invention.
The experiment described in Example 2 was repeated exactly as described, but the 1,2-propylene glycol was replaced by an equal weight of ethylene glycol. The product so obtained separated into two layers on being allowed to cool to room temperature.
- Example 4 This example demonstrates the effect of using the aliphatic diol in an amount greater than the amount by 104~4~
weight of scrap foam.
A batch (23 g.) of comminuted scrap from the flexible foam described in Example 1 was added incrementally, over a period of 1 hour, to 48.7 g. of 1,2-propylene glycol maintained at 200 - 230C with agitation. The resulting mixture was maintained at a temperature within the above range for a further 8 hours with agitation and was then allowed to cool to room temperature (circa 20C). After standing at the latter temperature for a very short period the initially homogeneous product separated into two layers.
Example 5 A further batch (20 g.) of comminuted scrap from the flexible foam described in Example 1 was added incrementally, over a period of 3 hours and 25 minutes, to 20 g. of 1S2-butanediol maintained at 200 to 223C with agitation. After the addition was complete, the mixture was maintained at a temperature in the above rang~ with agitation for a further 3.5 hours and was then allowed to cool to room temperature (20C). The product so obtained (39 g.) was a brown mobile liquid which was homogeneous and showed no tendency to separate into two layers on standing. The product had a viscosity of 396 centisto~es at 20C and a hydroxyl equivalent weight of 91.
Exam~le 6 A further batch (20 g.) of comminuted scrap from the flexible foam described in Example 1 was added incrementally, over a period of 2 hours, to 20 9. of 3-methylpentane-1,5 - diol maintained at 200 to 228C with agitation, The result-; ing mi~ture was maintained at a temperature in the above range for a further 5 hours with agitation before being 4tj allowed to cool to room temperature (20C). The resulting brown liquid(39.2 g.) showed no tendency to separate into two layers even after allowing to stand for several weeks.
The product had a viscosity of 2018 centistokes at 20C
and an hydroxyl equivalent weight of 120.
,Example 7 The scrap employed in this example was taken from a commercially available polyether-based flexible foam (2 pcf density) in the form of bunstock sold by the CPR
Division of The Upjohn Company as flexible foam "CPR
9700-2.0 WFR".
' An aliquot of 50 g. of scrap from the above foam , was comminuted and then added incrementally, over a period - of 3 hours, to 25 g. of 1,2-propylene glycol maintained at - 15 200 to 234C with agitation. The resulting mixture was maintained at a temperature in the above range for a period of a further 5 hours with agitation and then was allowed to cool to room temperature (20C). The result-ing brown liquid (70.5 g.) was homogeneous and showed no tendency to separate even upon standing for several weeks. The product had a viscosity of 1271 centistokes at 20C and an hydroxyl equivalent weight of 98.5.
ExamDle 8 A mixture was prepared of 20 g. of comminuted scrap flexible foam from the commercially available flexible foam described in Example 7 and 20 9. of comminuted scrap ' from a semi-flexible foam prepared using the following reactants in the proportions (all parts by weight) set -- forth below~
*Trade Mark '10~z~4~;
Polymethylene polyphenyl polyisocyanatel : 64.2 parts Polyether (propoxylated trimethylolpropane: 100 parts eq. wt. - 2000) Aromatic based polyol2 :10 parts N,N',Nn-tris(dimethylaminopropyl)hexa- : 0.7 part hydrotriazine [5~/O w/w solution in aromatic based poLyol2]
Triethanolamine : 4 parts Water : 2 parts Dibutyltin dilaurate :0.5 part Trichlorofluoromethane 10 parts The foam was prepared by thoroughly admixing all the components except the isocyanate and then adding the latter - to the preblend of the other com'ponents and subjecting the resulting mixture to high speed mechanical stirring for 10 seconds. The resulting foam was cured at 25C
for 7 days.
The mixt~re of scrap foams was added in increments, with stirring, over a period of 2 hours and 15 minutes to 25 g. of 1,2-propylene glycol maintained at 200 to 230C. When the addition of scrap was complete, the mixture was maintained at the above temperature with stirring for a further 5.5 hrs. and then allowed to cool to room temperature (circa 20C). There was thus obtained 60.9 g. o a mobile homogeneous mixture of polyols having a viscosity of 1042 centistokes at 20C and an hydroxyl 1 Containing approximately 6~h methylenebis(phenyl isocyanate) and having eq. wt. = 133.
2 Blend of N,N-di(2-hydroxypropyl)aniline and Mannich base polyol derived from nonylphenol, diethanol-amine and formaldehyde capped with propylene oxide eq. wt. = 104.5.
eguivalent weight of 91.
ExamPle 9 A mi~ture was prepared by blending 40 9. of comminuted scrap flexible foam from the commercially available flexible foam described in Example 7 and 20 g. of scrap from a rigid polyurethane foam which had been prepared using the following reactants in the proportions (all parts by weight) set forth below:
(1) A blend of the following polyols:
60 parts of a blend (eq. wt = 151) of (i) a polyol obtained by pro-poxylating a polymethylene poly- -phenyl polyamine containing approx-imately 50 percent by weight of methylenedianiline and (ii) a poLyol of eq. wt = 89 obtained by propoxy-lating glycerol;
30 parts of an adduct of phosphoric acid and propylene oxide having an equivalent weight of 148;
10 parts of trimethylolpropane.
(2) 2 parts of organosilicone surfactant (L-5410)
Unfortunately the process of the above cited patent, which is entirely satisfactory for rigid foams, cannot be applied successfully to the recovery of the major class of flexible foams, namely, those derived from a polyether polyol.
Thus, the process of the above patent, when employed with scrap from flexible, polyether-based foams, gives a product -2- ~
which separates into two layers, one of which is a polyol and the other appears to be a polyamine. The latter requires to be separated from the former and is not useful in the preparation of further polyurethane foams, although it has uses as a curing agent for epoxides and the like.
Substantially the same result is reported in U. S.
Patent 3,632 530 which describes the treatment of scrap flexible polyether-based polyurethane foam by heating in the presence of an aliphatic glycol and, optionally, a tertiary amine. The product separates into two layers one of which is polyol and the other is said to be polyamine.
; The latter is separated and shown to be useful as an amine curative for epoxy resins and for isocyanate-terminated prepolymers. As is evident from Example 9 of the above cited patent, there is no such problem with a polyester-based flexible foam. The latter gives rise to a homo-- geneous product which shows no tendency to separate into ' two layers.
~- Unfortunately, however, the bulk of the flexible foams currently produced commercially are derived from polyether polyols, and scrap from such foams has not so far been converted successfully to a homogeneous product which is , -usable in its entirety as a polyol cbmponent for the pre-~aration of new polyurethane foam.
We have now found that, contrary to previously reported experience, it i9 possible, by careful choice of reactants, and of proportions thereof, and of reaction conditions, to convert scrap, polyether-based flexible polyurethane foam into a homogeneous mixture of polyols, which mixture does not separate into different components but can be used in 3_ ~ ~?
' ' ~ ' . .
, 3064 4~j its entirety as part, or the whole, of the polyol component employed in the preparation of new polyurethane foam.
SUMMARY OF THE INVENTION
The invention comprises a process of converting scrap flexible polyurethane foam, which has been derived from a polyether polyol, to a homogeneous mixture of polyols, which process comprises heating, at a temperature in the range of 180C to 250C, a mixture of (a) said scrap flexible polyurethane foam, preferably in a comminuted form, and 10 (b) an aliphatic diol having the formula HO -A -OH wherein A is selected from the class consisting of an alkylene radical from 2 to 6 carbon atoms, inclusive, and an alkylene radical from 2 to 6 carbon atoms wherein the chain thereof is interrupted by an oxygen atom, both of which alkylene radicals carry at least one lower-alkyl substituent on a carbon atom in the chain thereof, said di.ol being present in an amount by weight which does not exceed the total weight of said scrap foam.
The invention also comprises the polyol recovered in accordance with the above process.
The recovered polyol is useful, either alone or in admixture with virgin polyol, in the preparation of new polyurethane foam and, more particularly, in the preparation l -of new rigid polyurethane foam.
DETAILED DESCRIPTION OF THE INV~NTION
The term "alkylene radical from 2 to 6 carbon atoms, ` inclusive" means (CH8)n wherein n is an integer from 2 to 6, such as ethylene, propylene, butylene, pentylene, .
- hexylene. The term ~alkylene radical from 2 to 6 carbon-atoms, inclusive, wherein the chain thereof is interrupted ;. ~ .
- ' ' ' " ~ ' ' `
-- ...
by an oxygen atom" means a radical of the formula (CHa)X 0 - (CH2)y wherein x and y are each integers and wherein the sum of x ~ y is a whole number from 2 to 6.
The term "lower-alkyl" means alkyl from l to 6 carbon atoms, inclusive, such as methyl, ethyl, propyl, butyl~
pentyl, hexyl and isomeric forms thereof.
It will be apparent from the above definitions that the aliphatic diols employed in the process of the invention are those in which the alkylene group separating the two hydroxyl groups must be branched, i.e. there is a lower-alkyl - group present as a substituent on at least one of the carbon atoms of the alkylene chain. In addition to this alkyl substituent, there can, optionally, be an oxygen atom (i.e. an ether linkage) in the alkylene chain separating the two hydroxyl group.s~ Illustrative of aliphatic diols which meet the above requirements are 1,2-propylene glycol~
- 1,2-butanediol, 1,2-hexanediol, di(l~2-propylene glycol), ~ di(L,2-butylene glycol), 3-methylpentane-1,5-diol, 2~2-dimethyl-1,3-propanediol, 1,2-octanediol, and mixtures of two or more of any of these diols.
It is to be noted that certain of .he above glycols have been suggested previously as media in which to carry out the heat degradation of scrap flexible foam, see U. S. 3~632~530O However, the results reported in that patent with these diols, and a series of other closely related diols, always show the production of a product which separates into two layers, one of which constitutes polyol and the other amine. Although it is di~closed ln general terms by the reference that proportions of scrap ; 30 foam to glycol as high as equal amounts by weight can be -:' -4tj employed, the actual examples all use amounts of glycol which are considerably in excess, by weight, of the amount of scrap foam.
In contrast, we have found that, in the case of certain glycols only, namely, those in which the alkylene chain separating the hydroxyl groups is branched, it is possible to obtain an entirely different result to that hitherto described, provided that the proportion of scrap foam introduced into the admixture with the glycol is markedly increased over the proportion hitherto employed in the artO
Thus, by employing a glycol which meets the definition set forth above, and, further, by substantially increasing the proportion of scrap flexible polyether polyol-based foam to a minimum of at least an equal amount by weight based on glycol, and preferably in substantial excess of this amount, it has been found~ very surprisingly, that it lS
possible to convert said scrap foam to a homogeneous mixture of polyols. That is to say, the product shows no tendency to separate into two layers, as in the case of the prior art, and shows no indication of the presence of amine therein. Further,the entire product, rather than a minor proportion thereof, can be used as the polyol component, or as a part thereof, in the preparation of virgin poly-urethane foam.
As will be appreciated by one skilled in the art, this - is a highly advantageous and clearly unexpected finding particularly in view of the concentrated search which has been made by the polyurethane foam industry in recent years to find a commercially feasible and economic manner in which to recover scrap from flexible foam.
4~
In carrying out the process of the invention, the scrap flexible foam is advantageously chopped or ground to particles of relatively small size in order to reduce the volume of the scrap and to assist in reducing the time necessary for the reaction to take place~ The scrap foam and the appropriate diol defined above are then brought together in a single operation, if desired, and the resulting mixture is heated to a temperature in the range of about 180~C to about 250C, advantageously with agitation. Alternatively and preferably, the diol is heated to a temperature in the above range and the comminuted scrap foam is added thereto in increments with agitation.
As set forth above, the proportions in which the scrap foam and the aliphatic diol are employed in the process of - the invention are such that the amount of scrap foam by weight is at least equal to the amount by weight of aliphatic diol. Preferably the scrap foam is employed in a proportion corresponding to from about 1.5 times to about } 20 2 times the amount by weight of diol which is employed~
Once the admixture of scrap foam and aliphatic diol has been completed, preferably with agitation, the mixture is maintained at a temperature within the above range at least until all the scrap foam has dissolved and a homogeneous solution has been obtained. The end point of the reaction, namely, the point at which degradation of the scrap to a - useful polyol has been completed9 can be detected by routine techniques, for example, by infrared spectroscopic analysis, or by observing the rate of change of viscosity.
In general, the period of heating necessary to recover the 4~
scrap foam as polyol will range from about 2 hours to about 12 hours depending upon thelnature of the scrap polyurethane foam and diol which are employed. The most desirable reaction time for any particular combination of scrap foam and diol can be determined by a process of trial and error.
When the degradation of scrap foam is complete, as determined by routine analytical tests such as those described above, the reaction mixture is cooled, or allowed to cool, to room temperature. Depending upon the origin of the scrap foam it may be necessary to remove small quantities of particulate matter (e.g. fibers, non-polyurethane dust, laminate foil and the like) from the product by filtration or like techniques.
Subject to the necessity for such treatment the product derived above is ready, without any further modification, for use as the polyol component in the preparation of new polyurethane foam.
The product generally has an hydroxyl equivalent w~ight in the range of about 65 to about 120 and is accordingly preferably used in the preparation of rigid polyurethane foams or for any other purpose, e.g. as a minor component in the preparation of polyisocyanurate foams, for which polyols having equivalent weights within this range are normally used. If desired, the polyol mixture obtained by the process of the invention can be blended with virgin polyol prior to conversion to polyurethane and the like foams.
Alternatively, the hydroxyl equivalent weight of the polyol mixture obtained by the process of the invention can - be modified, i.e. increased, if desired, by reacting the recovered polyol with an alkylene oxide such as ethylene -- --104~1~5 oxide, propylene oxide and the like. The alko~ylation can be carried out by processes well-recognized in the art optionally in the presence of a basic catalyst such as potassium hydroxide, sodium hydroxide, and the like.
It has also been found surprisingly that substantial amounts of scrap foam derived from semi-rigid (also some-times known as semi-fle~ible) and/or rigid polyurethane or polyisocyanurate foams can be combined with the scrap flexible, polyether-based foams employed in the process of the invention without detracting from the overall result, - i.e. the production of a homogeneous mixture of polyols suitable for re-use in the preparation of polyurethane and like foams. Thus, it has been found that quantities of .~ . .
- scrap semi-rigid and/or rigid polyurethane or polyisocyanurate foam. Up to ahol~t 75 percent by weight, based on the scrap flexible polyether based foam, can be incorporated into the `- reaction mixture employed in the process of the invention.
Preferably, the various types of scrap foam are pre-blended before being added to the aliphatic diol, but the different types of scrap foam can be added separately to the aliphatic diol if desired.
When the flexible foam is subjected to the process of the invention in combination with scrap from other types of foam as discussed above, it is necessary that the total amount of scrap be such that the proportion of total scrap foam to aliphatic diol be always within the limits discussed above.
It is pertinent to note that, where the scrap flexible foam is subjected to the process of the invention in combin-ation with substantial quantities of scrap from the other _g_ sources described above, said scrap fle~ible foam can be present in the reaction mixture in an amount which represents less than an equal amount by weight compared to the aliphatic diol present in said reaction mixture.
Yet, provided that the total weight of flexible and other types of scrap foam present in the reaction is still at least equal by weight to the amount of aliphatic diol present therein, the overall desired result will still be obtained, i.e. the reaction product will be a homogeneous mi~ture of polyols. This finding is clearly contrary to the result which would be achieved were the scrap flexible foam to be employed alone in the same proportion by weight.
The viscosity of the reaction product obtained in ; accordance with the process of the invention is largely governed by the particular diol and scrap foam used and by the proportions in which they are used in the range set forth above. Advantageously, the viscosity of the , reaction product is within the range of about 300 centi-stokes to about 4,500 centistokes measured at 25C. A
viscosity in this range can be attained readily in the case of any particular diol and scrap polyurethane by a process of trial and error.
While any of the branched chain aliphatic diols falling within the definitions given above can be used in the process of the invention, a particularly preferred diol is 1,2-propylene glycol. It is to be noted in this regard that closely related aliphatic diols such as - ethylene glycol, diethylene glycol and butane-1,4-diol~
which differ only from the diols employed in the process of the invention by the absence of branching in the alkylene ..
~(~4~1~6 chain, do not give rise to a homogeneous mixture of polyols when employed under exactly the same conditions. Thus, the straight chain aliphatic diols such as those enumerated above, when heated with scrap flexible polyether-based foam 5 at the temperatures and in the proportions corresponding to those employed in the process of the invention, give rise to products which separate into two layers of different character, in contrast to the homogeneous mixturesobtained in accordance with the invention.
As will be obvious to one skilled in the art, the process of the invention can, if desired, be operated on a continuous basis. For example, the scrap foam and the aliphatic diol can be fed in separate streams, or after preblending if desired, to a continuous tube reactor in which the reactants are agitated and subjected to a temperature within the range set forth above. The residence time, or hold up time, in the reactor is adjusted so that the conversion to homogeneous polyol is effected in a single pass through the reactor. Alternatively, the reaction mixture can be continuously recycled through the reactor a plurality of times until the total residence `, time in the reactor is such as to accomplish the desired conversion. In a further alternative mode of operation on a continuous basis, the preliminary step of comminuting the scrap foam can be omitted and the scrap foam can be fed to a continuous reactor which is provided with means for crushing or comminuting the scrap foam in contact with the aliphatic diol preferably at a temperature within the ; range set forth above. Other modes of operation on a continuous basis will be readily apparent to one skilled in 14~
the art.
The following examples describe the manner and pro-cess of making and using the invention and set forth the best mode contemplated by the inventors of carrying out the invention but are not to be construed as limiting.
~xamDle 1 The scrap foam employed as starting material in the process described in this Example was obtained from a flexible foam which had been prepared using the following reactantS in the proportions (parts by weight) set forth below.
Toluene diisocyanate (80/20) u 49 parts Propoxylated glycerol * : 100 parts (eq. wt. = 1000; LG-56, Union Carbide) Stannous octoate - : 0.22 part N-ethylmorpholine u 0.25 part Triethylenediamine ~ 0 3 part Surfactant (L-520) . 1.0 parts Water u 4,0 parts ~he foam was prepared by thoroughly admixing all the components except the isocyanate and then adding the latter to the preblend of the other components and subjecting the resulting mixture to high speed mechanical stirring for 10 seconds. The resulting foam was cured at 25C for 7 days.
A batch ~25 9.) of scrap from the above foam was comminuted in a Wiley laboratory mill and added in incre-ments, over a period of 2 hour~ and 50 minutes, to 25 9.
of 1,2-propylene glycol maintained at 200C to 225C with . .
stirring. After the addition was complete, the mixture was heated with agitation for a further 6 hours ~approx.) until - ~ ~Trade Ma~ks 4~
a clear homogeneous solution was obtained. The resulting product was allowed to cool to room temperature (circa 20VC) and was found to remain a homogeneous liquid even after standing for several weeks. The product (48 g.) was dark brown and mobile, and had a viscosity of 407 centistokes at 20C and a hydroxyl equivalent weight of 81.5.
Example 2 A second batch of 40 g. of scrap from the flexible foam described in Example 1 was comminuted and added in 10 increments over a period of 4 hours and 25 minutes to 25 g.
of propylene glycol maintained at 200 to 234C with agitation.
When the addition was complete, the mixture was maintained for a further 6.5 hours within the same temperature range - with agitation. At the end of this time, the mixture was allowed to cool to room temperature (20C) to yield 60.6 g.
of a brown homogeneous mobile liquid which had a viscosity of 607 centistokes at 20C and a hydroxyl equivalent weight -- of 101.
Example 3 ` 20 This example illustrates the different result obtained using an aliphatic glycol other than those called for by the process of the invention.
The experiment described in Example 2 was repeated exactly as described, but the 1,2-propylene glycol was replaced by an equal weight of ethylene glycol. The product so obtained separated into two layers on being allowed to cool to room temperature.
- Example 4 This example demonstrates the effect of using the aliphatic diol in an amount greater than the amount by 104~4~
weight of scrap foam.
A batch (23 g.) of comminuted scrap from the flexible foam described in Example 1 was added incrementally, over a period of 1 hour, to 48.7 g. of 1,2-propylene glycol maintained at 200 - 230C with agitation. The resulting mixture was maintained at a temperature within the above range for a further 8 hours with agitation and was then allowed to cool to room temperature (circa 20C). After standing at the latter temperature for a very short period the initially homogeneous product separated into two layers.
Example 5 A further batch (20 g.) of comminuted scrap from the flexible foam described in Example 1 was added incrementally, over a period of 3 hours and 25 minutes, to 20 g. of 1S2-butanediol maintained at 200 to 223C with agitation. After the addition was complete, the mixture was maintained at a temperature in the above rang~ with agitation for a further 3.5 hours and was then allowed to cool to room temperature (20C). The product so obtained (39 g.) was a brown mobile liquid which was homogeneous and showed no tendency to separate into two layers on standing. The product had a viscosity of 396 centisto~es at 20C and a hydroxyl equivalent weight of 91.
Exam~le 6 A further batch (20 g.) of comminuted scrap from the flexible foam described in Example 1 was added incrementally, over a period of 2 hours, to 20 9. of 3-methylpentane-1,5 - diol maintained at 200 to 228C with agitation, The result-; ing mi~ture was maintained at a temperature in the above range for a further 5 hours with agitation before being 4tj allowed to cool to room temperature (20C). The resulting brown liquid(39.2 g.) showed no tendency to separate into two layers even after allowing to stand for several weeks.
The product had a viscosity of 2018 centistokes at 20C
and an hydroxyl equivalent weight of 120.
,Example 7 The scrap employed in this example was taken from a commercially available polyether-based flexible foam (2 pcf density) in the form of bunstock sold by the CPR
Division of The Upjohn Company as flexible foam "CPR
9700-2.0 WFR".
' An aliquot of 50 g. of scrap from the above foam , was comminuted and then added incrementally, over a period - of 3 hours, to 25 g. of 1,2-propylene glycol maintained at - 15 200 to 234C with agitation. The resulting mixture was maintained at a temperature in the above range for a period of a further 5 hours with agitation and then was allowed to cool to room temperature (20C). The result-ing brown liquid (70.5 g.) was homogeneous and showed no tendency to separate even upon standing for several weeks. The product had a viscosity of 1271 centistokes at 20C and an hydroxyl equivalent weight of 98.5.
ExamDle 8 A mixture was prepared of 20 g. of comminuted scrap flexible foam from the commercially available flexible foam described in Example 7 and 20 9. of comminuted scrap ' from a semi-flexible foam prepared using the following reactants in the proportions (all parts by weight) set -- forth below~
*Trade Mark '10~z~4~;
Polymethylene polyphenyl polyisocyanatel : 64.2 parts Polyether (propoxylated trimethylolpropane: 100 parts eq. wt. - 2000) Aromatic based polyol2 :10 parts N,N',Nn-tris(dimethylaminopropyl)hexa- : 0.7 part hydrotriazine [5~/O w/w solution in aromatic based poLyol2]
Triethanolamine : 4 parts Water : 2 parts Dibutyltin dilaurate :0.5 part Trichlorofluoromethane 10 parts The foam was prepared by thoroughly admixing all the components except the isocyanate and then adding the latter - to the preblend of the other com'ponents and subjecting the resulting mixture to high speed mechanical stirring for 10 seconds. The resulting foam was cured at 25C
for 7 days.
The mixt~re of scrap foams was added in increments, with stirring, over a period of 2 hours and 15 minutes to 25 g. of 1,2-propylene glycol maintained at 200 to 230C. When the addition of scrap was complete, the mixture was maintained at the above temperature with stirring for a further 5.5 hrs. and then allowed to cool to room temperature (circa 20C). There was thus obtained 60.9 g. o a mobile homogeneous mixture of polyols having a viscosity of 1042 centistokes at 20C and an hydroxyl 1 Containing approximately 6~h methylenebis(phenyl isocyanate) and having eq. wt. = 133.
2 Blend of N,N-di(2-hydroxypropyl)aniline and Mannich base polyol derived from nonylphenol, diethanol-amine and formaldehyde capped with propylene oxide eq. wt. = 104.5.
eguivalent weight of 91.
ExamPle 9 A mi~ture was prepared by blending 40 9. of comminuted scrap flexible foam from the commercially available flexible foam described in Example 7 and 20 g. of scrap from a rigid polyurethane foam which had been prepared using the following reactants in the proportions (all parts by weight) set forth below:
(1) A blend of the following polyols:
60 parts of a blend (eq. wt = 151) of (i) a polyol obtained by pro-poxylating a polymethylene poly- -phenyl polyamine containing approx-imately 50 percent by weight of methylenedianiline and (ii) a poLyol of eq. wt = 89 obtained by propoxy-lating glycerol;
30 parts of an adduct of phosphoric acid and propylene oxide having an equivalent weight of 148;
10 parts of trimethylolpropane.
(2) 2 parts of organosilicone surfactant (L-5410)
(3) 0.4 part of water
(4) 0.6 part of tetramethylguanidine
(5) 0.4 part of N,N,N',N'-tetramethylbutanediamine
(6) 33 parts of trichlorofluoromethane
(7) 140 parts of polymethylene polyphenyl polyisocyanate of eguivalent weight 134.
~~ Ingredients (1) to (6) were blended by mechanical mixing and the polyisocyanate (7) was added to the blend.
~Trade Mark ~ -17-f`.
The resulting mixture was subjected to high speed mechanical stirring for 10 seconds and then was allowed to foam freely.
The foam so obtained, after being cured for 7 days at circa 15C, was found to have a density of 2.03 pcf and S a compressive strength of 48.5 psi parallel to rise and 17.3 psi perpendicular to rise.
The mixture of scrap foams was added in increments, with stirring, over a period of 3 hours to 25 g. of propylene glycol maintained at 200C to 228C with agitation. After the addition was complete, the mixture was maintained for a further 5 hours and 15 minutes at the same temperature with stirring, and was then allowed to cool to room temperature (cirFa 20C). There was thus - obtained 80.5 9. of a mobile, homogeneous mixturè of polyols havinq a viscosit~ of 4~14 centistoXes at 20C
and an hydro~yl equivalent weight of 92.5.
ExamDle 10 :`
A total of 3000 9. of scrap from the commercially available flexible foam described in Example 7 was comminuted and added in increments, over a period of 5 hours,to 1500 g. of 1,2-propylene glycol maintained at 180 to 195C with agitation in an 18 Liter reactor. When the addition was complete the mixture was maintained within the same temperature range with stirring for an additional hour. Thereafter an additional 865 g. of 1,2-propylene glycol were added and the mixture was heated for an additional 2 hours at 190C with stirring. The resulting product was allowed to cool to room temperature (circa 20C). There was thus obtained 4832 g. of a mobile, homogeneous ~ixture of polyols having an hydroxyl equivalent - - n n~
la~z:l.4~
weight of 68.
A rigid foam was prepared by blending 50 parts by weight of the mixture of polyols obtained as described above with 50 parts by weight of a polyol of equivalent weight 151 which itself was a blend of (i) a polyol obtained by ~ropoxylating a polymethylene polyphenyl polyamine containing approximately 50 percent by weight of methylenedianiline and (ii) a polyol of equivalent weight 89 obtained by propoxylating glycerol.
The polyol mixture so obtained was blended with 2 parts by weight of triethylenediamine, 2 parts by weight of organosilicone surfactant and 42 parts by weight of trichlorofluoromethane, and to the resulting mixture was added 175 parts of polymethylene polyphenyl poly-isocyanate (equivaient weight i33;. ~he mixiure ~v obtdin~u was subjected to high speed mechanical stirring for 10 seconds and then allowed to foam freely. The foam which resulted was cured for 3 days at 20C and found to have the following properties:
Density - : 1.96 pcf Compressive strength:
- Perpendicular to rise: 18.1 psi .
~~ Ingredients (1) to (6) were blended by mechanical mixing and the polyisocyanate (7) was added to the blend.
~Trade Mark ~ -17-f`.
The resulting mixture was subjected to high speed mechanical stirring for 10 seconds and then was allowed to foam freely.
The foam so obtained, after being cured for 7 days at circa 15C, was found to have a density of 2.03 pcf and S a compressive strength of 48.5 psi parallel to rise and 17.3 psi perpendicular to rise.
The mixture of scrap foams was added in increments, with stirring, over a period of 3 hours to 25 g. of propylene glycol maintained at 200C to 228C with agitation. After the addition was complete, the mixture was maintained for a further 5 hours and 15 minutes at the same temperature with stirring, and was then allowed to cool to room temperature (cirFa 20C). There was thus - obtained 80.5 9. of a mobile, homogeneous mixturè of polyols havinq a viscosit~ of 4~14 centistoXes at 20C
and an hydro~yl equivalent weight of 92.5.
ExamDle 10 :`
A total of 3000 9. of scrap from the commercially available flexible foam described in Example 7 was comminuted and added in increments, over a period of 5 hours,to 1500 g. of 1,2-propylene glycol maintained at 180 to 195C with agitation in an 18 Liter reactor. When the addition was complete the mixture was maintained within the same temperature range with stirring for an additional hour. Thereafter an additional 865 g. of 1,2-propylene glycol were added and the mixture was heated for an additional 2 hours at 190C with stirring. The resulting product was allowed to cool to room temperature (circa 20C). There was thus obtained 4832 g. of a mobile, homogeneous ~ixture of polyols having an hydroxyl equivalent - - n n~
la~z:l.4~
weight of 68.
A rigid foam was prepared by blending 50 parts by weight of the mixture of polyols obtained as described above with 50 parts by weight of a polyol of equivalent weight 151 which itself was a blend of (i) a polyol obtained by ~ropoxylating a polymethylene polyphenyl polyamine containing approximately 50 percent by weight of methylenedianiline and (ii) a polyol of equivalent weight 89 obtained by propoxylating glycerol.
The polyol mixture so obtained was blended with 2 parts by weight of triethylenediamine, 2 parts by weight of organosilicone surfactant and 42 parts by weight of trichlorofluoromethane, and to the resulting mixture was added 175 parts of polymethylene polyphenyl poly-isocyanate (equivaient weight i33;. ~he mixiure ~v obtdin~u was subjected to high speed mechanical stirring for 10 seconds and then allowed to foam freely. The foam which resulted was cured for 3 days at 20C and found to have the following properties:
Density - : 1.96 pcf Compressive strength:
- Perpendicular to rise: 18.1 psi .
Claims
A process for converting scrap flexible polyurethane foam, which foam has been derived from a polyether polyol, to a homogeneous mixture of polyols, which process com-prises heating, at a temperature in the range of 180°C
to 250°C, a mixture of (a) said scrap flexible foam and (b) an aliphatic diol having the formula HO-A-OH
wherein A isselected from the class consisting of an alkylene radical from 2 to 6 carbon atoms, and an alkylene radical from 2 to 6 carbon atoms wherein the chain thereof is interrupted by an oxygen atom, both of which alkylene radicals carry at least one lower-alkyl sub-stituent on a carbon atom in the chain thereof, said diol being present in an amount by weight which does not exceed the total weight of said scrap foam.
The process of Claim 1 wherein the said scrap flexible foam is employed in an amount by weight corresponding to from about 1 to about 2 times the amount by weight of said aliphatic diol.
The process of Claim 1 wherein the aliphatic diol is 1,2-propylene glycol.
The process of Claim 1 wherein the aliphatic diol is
1,2-butanediol.
The process of Claim 1 wherein the aliphatic diol is 3-methylpentane-1,5-diol.
The process of Claim 1, 2 or 3 wherein the said scrap flexible foam is employed in combination with scrap from a foam selected from the class consisting of semi-rigid polyurethane foam, rigid polyurethane foam, and rigid poly-isocyanurate foam.
The process of Claim 1, 2 or 3 wherein said scrap flexible foam (a) is in a comminuted form.
Page 21 of 21 Pages.
The process of Claim 1 wherein the aliphatic diol is 3-methylpentane-1,5-diol.
The process of Claim 1, 2 or 3 wherein the said scrap flexible foam is employed in combination with scrap from a foam selected from the class consisting of semi-rigid polyurethane foam, rigid polyurethane foam, and rigid poly-isocyanurate foam.
The process of Claim 1, 2 or 3 wherein said scrap flexible foam (a) is in a comminuted form.
Page 21 of 21 Pages.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US46485674A | 1974-04-29 | 1974-04-29 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1042146A true CA1042146A (en) | 1978-11-07 |
Family
ID=23845529
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA223,810A Expired CA1042146A (en) | 1974-04-29 | 1975-04-03 | Process for reclaiming flexible polyurethane foam |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPS5329359B2 (en) |
| CA (1) | CA1042146A (en) |
| DE (1) | DE2516863B2 (en) |
| ES (1) | ES436853A1 (en) |
| FR (1) | FR2268825B1 (en) |
| GB (1) | GB1492838A (en) |
| IT (1) | IT1035248B (en) |
| NL (1) | NL159418B (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2951617C2 (en) * | 1979-12-21 | 1985-08-14 | Wilhelm Prof. Dr.-Ing. 5100 Aachen Schütz | Process and system for processing polyurethane |
| DE3232461A1 (en) * | 1982-09-01 | 1984-03-01 | Bayer Ag, 5090 Leverkusen | METHOD FOR CONTINUOUS GLYCOLYTIC HIGH-TEMPERATURE DEGRADATION OF POLYURETHANE PLASTIC DISPENSING IN SCREW MACHINES |
| DE3618007A1 (en) * | 1986-05-28 | 1987-12-03 | Bayer Ag | METHOD FOR PRODUCING HYDROXYPHENYLURETHANES |
| DE4024601C2 (en) * | 1990-08-02 | 1997-04-03 | Gunter Prof Dr Bauer | Process for the preparation of polyol-containing dispersions and their use |
| DE4234335A1 (en) | 1992-10-12 | 1994-04-14 | Basf Schwarzheide Gmbh | Process for the production of recycled polyols and their use in the production of polyurethanes |
| GB9223943D0 (en) * | 1992-11-14 | 1993-01-06 | Caligen Foam Ltd | Re-cycling of polyurethane foam |
| DE4323558C2 (en) * | 1993-07-14 | 2001-02-15 | Gore & Ass | Process for the isolation and recycling of textile materials from polyurethane-bonded textile laminates |
| DE4411864A1 (en) * | 1994-04-08 | 1995-10-12 | Basf Schwarzheide Gmbh | Process for the production of hard to tough polyurethane foams with an increased proportion of open cells and reduced shrinkage |
| DE4433834C1 (en) * | 1994-09-22 | 1995-10-12 | Daimler Benz Ag | Recovering waste from synthetic diol-di:isocyanate adducts contg. non-glycolisable material, |
| DE4442379A1 (en) | 1994-11-29 | 1996-05-30 | Bayer Ag | Process for the glycolytic degradation of polyurethane plastics |
| JP2011246569A (en) * | 2010-05-26 | 2011-12-08 | Inoac Corp | Recyclable polyurethane foam, method of manufacturing recycled polyol, and method of manufacturing polyurethane foam using the recycled polyol |
| CN112029148A (en) * | 2020-08-31 | 2020-12-04 | 浙江工业大学 | Method for recycling polyether polyol in waste polyurethane foam by using emulsion system |
-
1975
- 1975-04-03 CA CA223,810A patent/CA1042146A/en not_active Expired
- 1975-04-07 GB GB1418675A patent/GB1492838A/en not_active Expired
- 1975-04-09 IT IT4901975A patent/IT1035248B/en active
- 1975-04-15 NL NL7504473A patent/NL159418B/en not_active IP Right Cessation
- 1975-04-17 DE DE19752516863 patent/DE2516863B2/en not_active Ceased
- 1975-04-22 ES ES436853A patent/ES436853A1/en not_active Expired
- 1975-04-28 FR FR7513221A patent/FR2268825B1/fr not_active Expired
- 1975-04-28 JP JP5195875A patent/JPS5329359B2/ja not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| FR2268825B1 (en) | 1977-07-08 |
| IT1035248B (en) | 1979-10-20 |
| DE2516863B2 (en) | 1977-03-03 |
| GB1492838A (en) | 1977-11-23 |
| DE2516863A1 (en) | 1975-10-30 |
| JPS50149606A (en) | 1975-11-29 |
| AU7984375A (en) | 1976-10-07 |
| NL7504473A (en) | 1975-10-31 |
| ES436853A1 (en) | 1976-12-01 |
| FR2268825A1 (en) | 1975-11-21 |
| JPS5329359B2 (en) | 1978-08-19 |
| NL159418B (en) | 1979-02-15 |
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