U.S. patent application number 09/945921 was filed with the patent office on 2002-06-13 for blowing agent blends.
Invention is credited to Bement, Leslie Bruce, Bogdan, Mary Charlotte, Logsdon, Peter Brian, Williams, David John.
Application Number | 20020072548 09/945921 |
Document ID | / |
Family ID | 23902312 |
Filed Date | 2002-06-13 |
United States Patent
Application |
20020072548 |
Kind Code |
A1 |
Bogdan, Mary Charlotte ; et
al. |
June 13, 2002 |
Blowing agent blends
Abstract
The invention relates to polyurethane and polyisocyanurate
closed-cell foams. More particularly, the invention relates to
polyurethane and polyisocyanurate closed-cell foams prepared with a
blowing agent comprising 1-chloro-1,2,2,2-tetrafluoroethane
(HCFC-124) and 1,1-dichloro-1-fluoroethane (HCFC-141b). Foams
prepared with the blowing agent of the invention possess improved
thermal performance.
Inventors: |
Bogdan, Mary Charlotte;
(West Seneca, NY) ; Bement, Leslie Bruce;
(Buffalo, NY) ; Logsdon, Peter Brian; (Orchard
Park, NY) ; Williams, David John; (East Amherst,
NY) |
Correspondence
Address: |
Synnestvedt & Lechner LLP
2600 Aramark Tower
1101 Market Street
Philadelphia
PA
19107-2950
US
|
Family ID: |
23902312 |
Appl. No.: |
09/945921 |
Filed: |
September 4, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09945921 |
Sep 4, 2001 |
|
|
|
09479017 |
Jan 7, 2000 |
|
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Current U.S.
Class: |
521/131 ;
252/67 |
Current CPC
Class: |
C08J 2205/052 20130101;
C08J 2375/04 20130101; C08J 2203/14 20130101; C08J 9/149 20130101;
C08J 9/144 20130101; C08J 2203/142 20130101 |
Class at
Publication: |
521/131 ;
252/67 |
International
Class: |
C08J 009/00; F25D
001/00 |
Claims
What is claimed is:
1. A blowing agent composition comprising
1,1-dichloro-1-fluoroethane and
1-chloro-1,2,2,2-tetrafluoroethane.
2. The blowing agent composition of claim 1 wherein the
1,1-dichloro-1-fluoroethane is present in an amount of from about
50 to about 99 weight percent and the
1-chloro-1,2,2,2-tetrafluoroethane is present in an amount of from
about 1 to about 50 weight percent.
3. The blowing agent composition of claim 1 wherein the
1,1-dichloro-1-fluoroethane is present in an amount of from about
60 to about 99 weight percent and the
1-chloro-1,2,2,2-tetrafluoroethane is present in an amount of from
about 1 to about 40 weight percent.
4. The blowing agent composition of claim 1 wherein the
1,1-dichloro-1-fluoroethane is present in an amount of from about
70 to about 99 weight percent and the
1-chloro-1,2,2,2-tetrafluoroethane is present in an amount of from
about 1 to about 30 weight percent.
5. The blowing agent composition of claim 1 wherein the
1,1-dichloro-1-fluoroethane is present in an amount of from about
80 to about 99 weight percent and the
1-chloro-1,2,2,2-tetrafluoroethane is present in an amount of from
about 1 to about 20 weight percent.
6. The blowing agent composition of claim 1 wherein the
1,1-dichloro-1-fluoroethane is present in an amount of from about
90 to about 99 weight percent and the
1-chloro-1,2,2,2-tetrafluoroethane is present in an amount of from
about 1 to about 10 weight percent.
7. A method of preparing polyurethane and polyisocyanurate foam
compositions comprising reacting and foaming a mixture of
ingredients which react to form polyurethane or polyisocyanurate
foams in the presence of the blowing agent of claim 1.
8. A closed cell foam composition prepared from a polymer foam
formulation containing the blowing agent of claim 1.
9. A premix of a polyol and a blowing agent wherein the blowing
agent comprises the blowing agent composition of claim 1.
Description
FIELD OF THE INVENTION
[0001] The invention relates to polyurethane and polyisocyanurate
closed-cell foams. More particularly, the invention relates to
polyurethane and polyisocyanurate closed-cell foams prepared with a
blowing agent comprising 1-chloro-1,2,2,2-tetrafluoroethane
(HCFC-124) and 1,1-dichloro-1-fluoroethane (HCFC-141b). Foams
prepared with the blowing agent of the invention possess improved
cell nucleation and thermal performance.
BACKGROUND OF THE INVENTION
[0002] The class of foams known as low density rigid polyurethane
or polyisocyanurate foam has utility in a wide variety of
insulation applications including roofing systems, building panels,
refrigerators and freezers. A critical factor in the large-scale
commercial acceptance of rigid polyurethane foams in the building
insulation industry has been their ability to provide a good
balance of properties. Rigid polyurethane and polyisocyanurate
foams are known to provide outstanding thermal insulation,
excellent fire properties and superior structural properties at
reasonably low densities.
[0003] The methods of producing polyurethane and polyisocyanurate
foams are generally known and consist in general of the reaction of
an organic polyisocyanurate (including diisocyanate) and a polyol
or mixture of polyols in the presence of a volatile blowing agent,
which is caused to vaporize by the heat liberated during the
reaction of isocyanate and polyol. This reaction can be enhanced
through the use of amine and/or other catalysts as well as
surfactants. The catalysts ensure adequate curing of the foam,
while the surfactants regulate and control cell size.
Flame-retardants are traditionally added to rigid polyurethane or
polyisocyanurate foam to reduce its flammability.
[0004] The foam industry has historically used liquid fluorocarbon
blowing agents such as trichlorofluoromethane (CFC-11) and
1,1-dichloro-1-fluoroethane (HCFC-141b) because of their ease of
use in processing conditions. Fluorocarbons act not only as blowing
agents by virtue of their volatility, but also are encapsulated or
entrained in the closed cell structure of the rigid foam and are
the major contributor to the low thermal conductivity properties of
rigid urethane foams.
[0005] The use of a fluorocarbon as the preferred commercial
expansion or blowing agent in insulating foam applications is based
in part on the resulting k-factor associated with the foam
produced. K-factor is defined as the rate of transfer of heat
energy by conduction through one square foot of one inch thick
homogenous material in one hour where there is a difference of one
degree Fahrenheit perpendicularly across the two surfaces of the
material. Since the utility of closed-cell polyurethane-type foams
is based, in part, upon their thermal insulation properties, it
would be advantageous to identify materials that produce lower
k-factor foams.
[0006] 1-chloro-1,2,2,2-tetrafluoroethane (HCFC-124) is a known
blowing agent. It has now been discovered that the use of HCFC-124
as a co-blowing agent for 1,1-dichloro-1-fluoroethane HCFC-141b
unexpectedly results in foams having superior thermal performance
to foam produced with HCFC-141b. The results are unexpected since
one would anticipate on the basis of vapor thermal conductivity
that the addition of HCFC-124 to HCFC-141b systems would elevate
the k-factor of the foam produced.
DETAILED DESCRIPTION OF THE INVENTION
[0007] The invention relates to a blowing agent composition
comprising 1,1-dichloro-1-fluoroethane and
1-chloro-1,2,2,2-tetrafluoroethane. The preferred compositions of
the invention are reported in the Table below. The ranges reported
in the table are in weight percent based on the total amount of
blowing agent composition and are understood to be prefaced by
"about".
1 % HCFC-124 % HCFC-141b in blowing in blowing agent agent
composition composition 50-99 1-50 60-99 1-40 70-99 1-30 80-99 1-20
90-99 1-10
[0008] In one embodiment, the invention provides a method of
preparing foam compositions based on isocyanate which comprises
reacting and foaming a mixture of ingredients which will react to
form polyurethane or polyisocyanurate foams in the presence of the
blowing agent composition of the invention.
[0009] In another embodiment, the invention provides a closed cell
foam prepared from a polymer foam formulation containing the
blowing agent composition of the invention.
[0010] In yet another embodiment, the invention provides a polyol
premix composition comprising a polyol and the blowing agent
composition of the invention.
[0011] With respect to the preparation of rigid or flexible
polyurethane or polyisocyanurate foams using hydrocarbons as the
blowing agent, any of the methods well known in the art can be
employed. See Saunders and Frisch, Volumes I and II Polyurethanes
Chemistry and Technology (1962). In general, polyurethane or
polyisocyanurate foams are prepared by combining an isocyanate, a
polyol or mixture of polyols, a blowing agent or mixture of blowing
agents, and other materials such as catalysts, surfactants, and
optionally, flame retardants, colorants, or other additives.
[0012] It is convenient in many applications to provide the
components for polyurethane or polyisocyanurate foams in
pre-blended foam formulations. Most typically, the foam formulation
is pre-blended into two components. The isocyanate or
polyisocyanate composition comprises the first component, commonly
referred to as the "A" component. The polyol or polyol mixture,
surfactant, catalysts, blowing agents, flame retardant, and other
isocyanate reactive components comprise the second component,
commonly referred to as the "B" component. While the surfactant,
catalyst(s) and blowing agent are usually placed on the polyol
side, they may be placed on either side, or partly on one side and
partly on the other side. Accordingly, polyurethane or
polyisocyanurate foams are readily prepared by bringing together
the A and B side components either by hand mix, for small
preparations, or preferably machine mix techniques to form blocks,
slabs, laminates, pour-in-place panels and other items, spray
applied foams, froths, and the like. Optionally, other ingredients
such as fire retardant, colorants, auxiliary blowing agents, water,
and even other polyols can be added as a third stream to the mix
head or reaction site. Most conveniently, however, they are all
incorporated into one B component.
[0013] Any organic polyisocyanate can be employed in polyurethane
or polyisocyanurate foam synthesis inclusive of aliphatic and
aromatic polyisocyanates. Preferred, as a class is the aromatic
polyisocyanates. Preferred polyisocyanates for rigid polyurethane
or polyisocyanurate foam synthesis are the polymethylene polyphenyl
isocyanates, particularly the mixtures containing from about 30 to
about 85 percent by weight of methylenebis(phenyl isocyanate) with
the remainder of the mixture comprising the polymethylene
polyphenyl polyisocyanates of functionality higher than 2.
Preferred polyisocyanates for flexible polyurethane foam synthesis
are toluene diisocyanates including, without limitation,
2,4-toluene diisocyanate, 2,6-toluene diisocyanate, and mixtures
thereof.
[0014] Typical polyols used in the manufacture of rigid
polyurethane foams include, but are not limited to, aromatic
amino-based polyether polyols such as those based on mixtures of
2,4- and 2,6-toluenediamine condensed with ethylene oxide and/or
propylene oxide. These polyols find utility in pour-in-place molded
foams. Another example is aromatic alkylamino-based polyether
polyols such as those based on ethoxylated and/or propoxylated
aminoethylated nonylphenol derivatives. These polyols generally
find utility in spray applied polyurethane foams. Another example
is sucrose-based polyols such as those based on sucrose derivatives
and/or mixtures of sucrose and glycerine derivatives condensed with
ethylene oxide and/or propylene oxide. These polyols generally find
utility in pour-in-place molded foams.
[0015] Typical polyols used in the manufacture of flexible
polyurethane foams include, but are not limited to, those based on
glycerol, ethylene glycol, trimethylolpropane, ethylene diamine,
pentaerythritol, and the like condensed with ethylene oxide,
propylene oxide, butylene oxide, and the like. These are generally
referred to as "polyether polyols". Another example is the graft
copolymer polyols, which include, but are not limited to,
conventional polyether polyols with vinyl polymer grafted to the
polyether polyol chain. Yet another example is polyurea modified
polyols which consist of conventional polyether polyols with
polyurea particles dispersed in the polyol.
[0016] Examples of polyols used in polyurethane modified
polyisocyanurate foams include, but are not limited to, aromatic
polyester polyols such as those based on complex mixtures of
phthalate-type or terephthalate-type esters formed from polyols
such as ethylene glycol, diethylene glycol, or propylene glycol.
These polyols are used in rigid laminated boardstock, and may be
blended with other types of polyols such as sucrose-based polyols,
and used in polyurethane foam applications.
[0017] Catalysts used in the manufacture of polyurethane foams are
typically tertiary amines including, but not limited to,
N-alkylmorpholines, N-alkylalkanolamines,
N,N-dialkylcyclohexylamines, and alkylamines where the alkyl groups
are methyl, ethyl, propyl, butyl and the like and isomeric forms
thereof, as well as heterocyclic amines. Typical, but not limiting,
examples are triethylenediamine, tetramethylethylenediamine,
bis(2-dimethylaminoethyl)ether, triethylamine, tripropylamine,
tributylamine, triamylamine, pyridine, quinoline,
dimethylpiperazine, piperazine, N,N-dimethylcyclohexylamine,
N-ethylmorpholine, 2-methylpiperazine, N,N-dimethylethanolamine,
tetramethylpropanediamine, methyltriethylenediamine, and mixtures
thereof.
[0018] Optionally, non-amine polyurethane catalysts are used.
Typical of such catalysts are organometallic compounds of lead,
tin, titanium, antimony, cobalt, aluminum, mercury, zinc, nickel,
copper, manganese, zirconium, and mixtures thereof. Exemplary
catalysts include, without limitation, lead 2-ethylhexoate, lead
benzoate, ferric chloride, antimony trichloride, and antimony
glycolate. A preferred organo-tin class includes the stannous salts
of carboxylic acids such as stannous octoate, stannous
2-ethylhexoate, stannous laurate, and the like, as well as dialkyl
tin salts of carboxylic acids such as dibutyl tin diacetate,
dibutyl tin dilaurate, dioctyl tin diacetate, and the like.
[0019] In the preparation of polyisocyanurate foams, trimerization
catalysts are used for the purpose of converting the blends in
conjunction with excess A component to
polyisocyanurate-polyurethane foams. The trimerization catalysts
employed can be any catalyst known to one skilled in the art
including, but not limited to, glycine salts and tertiary amine
trimerization catalysts, alkali metal carboxylic acid salts, and
mixtures thereof. Preferred species within the classes are
potassium acetate, potassium octoate, and
N-(2-hydroxy-5-nonylphenol)meth- yl-N-methylglycinate.
[0020] Dispersing agents, cell stabilizers, and surfactants may be
incorporated into the blowing agent mixture. Surfactants, better
known as silicone oils, are added to serve as cell stabilizers.
Some representative materials are sold under the names of DC-193,
B-8404, and L-5340 which are, generally, polysiloxane
polyoxyalkylene block co-polymers such as those disclosed in U.S.
Pat. Nos. 2,834,748, 2,917,480, and 2,846,458.
[0021] Other optional additives for the blowing agent mixture may
include flame retardants such as tris(2-chloroethyl) phosphate,
tris (2-chloropropyl) phosphate, tris (2,3-dibromopropyl)
phosphate, tris (1,3-dichloropropyl) phosphate, diammonium
phosphate, various halogenated aromatic compounds, antimony oxide,
aluminum trihydrate, polyvinyl chloride, and the like. Other
optional ingredients may include from 0 to about 3 percent water,
which chemically reacts with the isocyanate to produce carbon
dioxide. The carbon dioxide acts as an auxiliary-blowing agent.
[0022] Also included in the mixture are blowing agents. Generally
speaking, the amount of blowing agent present in the blended
mixture is dictated by the desired foam densities of the final
polyurethane or polyisocyanurate foams products. The polyurethane
foams produced can vary in density from about 0.5 pound per cubic
foot to about 40 pounds per cubic foot, preferably from about 1.0
to about 20.0 pounds per cubic foot, and most preferably from about
1.5 to about 6.0 pounds per cubic foot for rigid polyurethane foams
and from about 1.0 to about 4.0 pounds per cubic foot for flexible
foams. The density obtained is a function of how much of the
blowing agent, or blowing agent mixture, is present in the A and/or
B components, or that is added at the time the foam is
prepared.
EXAMPLE
[0023] The invention is further illustrated by the following
examples, in which parts or percentages are by weight unless
otherwise specified. The following materials were used in the
examples.
[0024] Polyol Blend: A polyester polyol with an OH number of 240
containing a compatibilizer to aid miscibility. It is a
commercially available from KOSA
[0025] HCFC-124: 1-chloro-1,2,2,2-tetrafluoroethane commercially
available from Honeywell International Inc.
[0026] HCFC-141b:1,1-dichloro-1-fluoroethane commercially available
from Honeywell International Inc.
[0027] Surfactant A: A polysiloxane polyether copolymer, which is
commercially available from Goldschmidt.
[0028] Catalyst A: An inorganic potassium based amine, which is
commercially available from Air Products
[0029] Catalyst B: A trimerization catalyst which is commercially
available from Air Products
Example 1
[0030] In this example, rigid polyisocyanurate foams were prepared
using the formulation shown in Table 1.
[0031] The foams were prepared by a general procedure commonly
referred to as "handmixing". For each blowing agent or blowing
agent pair, a premix of polyol, surfactant, and catalysts was
prepared in the same proportions displayed in Table 1. About 100
grams of each formulation was blended. The premix was blended in a
32 oz paint can, and stirred at about 1500 rpm with a Conn 2"
diameter ITC mixer until a homogeneous blend was achieved. When
mixing was complete, the can was covered and placed in a
refrigerator controlled at 32.degree. F. The foam blowing agent or
pre-blended pair of blowing agents was also stored in pressure
bottles at 32.degree. F. The A-component was kept in sealed
containers at 70.degree. F.
[0032] The pre-cooled blowing agent was added in the required
amount to the premix. The contents were stirred for two minutes
with a Conn 2" ITC mixing blade turning at 1000 rpm. Following
this, the mixing vessel and contents were re-weighed. If there was
a weight loss, the blowing agent or the blend was added to the
solution to make up any weight loss. The can is than covered and
replaced in the refrigerator.
[0033] After the contents have cooled again to 32.degree. F.,
approximately 10 minutes, the mixing vessel was removed from
refrigerator and taken to the mixing station. A pre-weighted
portion of A-component, isocyanurate, was added quickly to the
B-component, the ingredients mixed for 10 seconds using a Conn 2"
diameter ITC mixing blade at 3000 rpm and poured into a
8".times.8".times.4" cardboard cake box and allowed to rise. Cream,
initiation, gel and tack free times were recorded for the
individual polyurethane foam samples.
[0034] The foams were allowed to cure in the boxes at room
temperature for at least 24 hours. After curing, the blocks were
trimmed to a uniform size and densities measured. Any foams that
did not meet the density specification 1.9.+-.0.1 lb/ft.sup.3 were
discarded and new foams were prepared.
[0035] After ensuring that all the foams meet the density
specifications, the foams were tested for k-factor according to
ASTM C518. The k-factor results are listed in Table 1
2TABLE 1 B-side (wt. %) Experiment 1 Experiment 2 Polyol 64.7 65.7
Catalyst A 0.8 0.8 Catalyst B 3.9 3.9 Water 0 0 Surfactant A 1.3
1.3 1-chloro-1,2,2,2-tetrafluoroethane 10.8 0
1,1-dichloro-1-fluoroeth- ane 18.5 29 Index 250 250 Density 1.9 1.9
k-Factor @ 36.5.degree. F. Initial 0.133 0.138 k-Factor @
75.2.degree. F. Initial 0.148 0.147
[0036] The foams co-blown with HCFC-124 and HCFC-141b have
surprisingly better k-factors than foams produced with HCFC-124 or
HCFC-141b alone at low temperatures. At room temperature the
k-factors are equivalent. These results are contrary to expectation
since the vapor thermal conductivity of HCFC-124 (0.08496 @
70.degree. F.) is higher than that of HCFC-141b (0.0696 @
70.degree. F.), and one would expect the addition of HCFC-124 to
HCFC-141b to result in a foam having an elevated k-factor.
* * * * *