U.S. patent application number 13/056671 was filed with the patent office on 2011-06-09 for aromatic polyesters, polyol blends comprising the same and resultant products therefrom.
This patent application is currently assigned to DOW GLOBAL TECHNOLOGIES LLC. Invention is credited to Giuseppe Lista.
Application Number | 20110133122 13/056671 |
Document ID | / |
Family ID | 40810839 |
Filed Date | 2011-06-09 |
United States Patent
Application |
20110133122 |
Kind Code |
A1 |
Lista; Giuseppe |
June 9, 2011 |
AROMATIC POLYESTERS, POLYOL BLENDS COMPRISING THE SAME AND
RESULTANT PRODUCTS THEREFROM
Abstract
The present invention discloses low viscosity aromatic polyester
polyols suitable for blending with other polyols or other materials
mutually compatible with the polyester polyols to achieve
polyurethane and polyisocyanurate products. In particular the
present invention discloses polyester polyols comprising the
reaction of: A) an aromatic component comprising at 80 mole percent
or greater of terephthalic acid; B) polyethylene glycol having a
molecular weight from 150 to 1000; and C) a glycol different from
the glycol of B); wherein A, B, and C are present in the reaction
on a percent weight bases of 20 to 60 weight percent A); 40 to 75
weight percent of B); and 0 to 40 weight percent of C).
Inventors: |
Lista; Giuseppe; (Modena,
IT) |
Assignee: |
DOW GLOBAL TECHNOLOGIES LLC
Midland
MI
|
Family ID: |
40810839 |
Appl. No.: |
13/056671 |
Filed: |
August 4, 2009 |
PCT Filed: |
August 4, 2009 |
PCT NO: |
PCT/EP2009/060123 |
371 Date: |
January 31, 2011 |
Current U.S.
Class: |
252/182.12 ;
528/83; 560/73 |
Current CPC
Class: |
C08G 18/4252 20130101;
C08G 2110/0025 20210101; C08G 18/4213 20130101; C08J 9/04
20130101 |
Class at
Publication: |
252/182.12 ;
560/73; 528/83 |
International
Class: |
C08G 18/00 20060101
C08G018/00; C07C 69/76 20060101 C07C069/76; C09K 3/00 20060101
C09K003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 6, 2008 |
IT |
MI2008A001480 |
Claims
1. A polyester polyol comprising the reaction product of: A) an
aromatic component comprising at 80 mole percent or greater of
terephthalic acid; B) polyethylene glycol having a molecular weight
from 150 to 1000; and C) a glycol different from the glycol of B);
wherein A, B, and C are present in the reaction on a percent weight
bases of 20 to 60 weight percent A); 40 to 75 weight percent of B);
and 0 to 40 weight percent of C).
2. The polyol of claim 1 wherein the aromatic content comprises 85
mole percent or greater of terephthalic acid.
3. The polyol of claim 2 wherein the aromatic content comprises 95
mole percent or greater of terephthalic acid.
4. The polyol of claim 3 wherein the polyethylene glycol has a
molecular weight of less than 500.
5. The polyol of claim 4 wherein component C) is presenting an
amount from 1 to less than 30 weight percent of the reaction
mixture.
6. The polyol of claim 1 wherein component C) is ethylene glycol,
diethylene glycol, or a oxyalkylene glycol of the formula:
##STR00002## where R is hydrogen or a lower alkyl of 1 to 4 carbon
atoms and n is from 1 to 5 with the proviso that at least 10
percent of the R moieties are a lower alkyl group.
7. The polyol of claim 6 wherein component C is ethylene glycol or
diethylene glycol.
8. An aromatic polyester polyol having a viscosity of less than
2500 mPa*s at 25.degree. C. as measured by UNI EN ISO 3219 and a
hydroxyl number of 200 to 400.
9. The polyester of claim 8 wherein the polyol has a viscosity of
2000 mPa*s or less.
10. The polyester of 9 wherein 80 mole percent or more of the
aromatic content of the polyester is derived from terephthalic
acid.
11. A polyol composition comprising from 10 to 90 weight percent of
a polyol of claim 1 and the remainder is at least one second polyol
wherein the second polyol is a monol or polyether polyol having a
functionality of 2 to 8 and a molecular weight of 100 to
10,000.
12. The polyol composition of claim 11 wherein the second polyol
contains at least one polyol with a functionality of 2 to 6 and a
hydroxyl number of 200 to 1,200.
13-16. (canceled)
17. A reaction system for production a rigid foam comprising a
polyol composition of claim 12 and a polyisocyanate.
18. The reaction system of claim 17 wherein the isocyanate is of
the diphenylmethane-4,4'-diisocyanate series.
Description
[0001] The present invention relates generally to certain
polyesters polyols suitable for blending with other polyols or
other materials mutually compatible with the polyester polyols to
achieve polyurethane and polyisocyanurate products.
BACKGROUND OF THE INVENTION
[0002] The use of a polyol in the preparation of polyurethanes by
reaction of the polyol with a polyisocyanate in the presence of a
catalyst and perhaps other ingredients is well known. Aromatic
polyester polyols are widely used in the manufacture of
polyurethane and polyurethane-polyisocyanurate foams and
resins.
[0003] Aromatic polyester polyols are attractive because they tend
to be low in cost, yet can be used to produce a wide variety of
cellular foams having excellent properties and adaptable for many
end use applications. One class of aromatic polyester polyols used
commercially is polyol products produced by esterification of
phthalic acid or phthalic acid anhydride with an aliphatic
polyhydric alcohol, for example, diethylene glycol. This type of
polyester polyol is capable of reacting with organic isocyanates to
produce, for example, coatings, adhesives, sealants, and elastomers
("CASE materials"), that can have excellent characteristics, such
as tensile strength, adhesion, and abrasion resistance. Such
aromatic polyester polyols may also be used in formations for
production of rigid polyurethane or polyisocyanurate foam.
[0004] One problem generally encountered when using aromatic
polyester polyols, with a desirable high aromatic ring content, is
that they are generally characteristically high in dynamic
viscosity, making handling very difficult. Often, aromatic
polyester polyols must be diluted or dissolved in relatively large
amounts of a suitable solvent to enable producing low viscosity,
easy-to-apply coating compositions upon being mixed with a curing
or crosslinking agent.
[0005] Ideally, an aromatic polyester polyol has a dynamic
viscosity that is sufficiently low to allow ease of pumping and
mixing without the use of solvents or other viscosity modifying
additives. An aromatic polyester polyol having too great a dynamic
viscosity can cause difficulties in transfer of the material, as
for example from storage to reactor or from the final product to
the final application of the product. Excessive dynamic viscosity
also can be a serious obstacle to efficient mixing with other CASE
material ingredients, such as an isocyanate.
[0006] Thus, there is a need for low viscosity aromatic polyester
polyols that are economical to produce and can be converted into
cellular foams and other CASE materials having excellent
properties. It is further desirable to have an aromatic polyester
polyol having a low viscosity and can also meet the required needs
for flame retardation.
SUMMARY OF THE INVENTION
[0007] The present invention relates to a new and surprisingly
useful class of low viscosity aromatic polyester polyols having an
average functionality of about two, comprising the
inter-esterification reaction product of terephthalic acid and at
least one polyethylene diol. The invention also relates to methods
for making such aromatic polyester polyols and methods for using
such aromatic polyester polyols to produce CASE materials. The
invention further relates to cellular polyurethane and
polyurethane/polyisocyanurate foams made using such aromatic
polyester polyols. The polyester polyols of the present invention
may be utilized with a wide variety of blowing agents, including
water, hydrocarbon, chlorofluorocarbon, and non-chlorofluorocarbon
blowing agents.
[0008] The aromatic polyester polyols of the present invention can
be readily blended with prior art polyols, if desired, and also
with various additives conventionally used in the formulation of
resin pre-polymer blends. The aromatic polyester polyols of the
invention are prepared by an inter-esterification process that is
simple, reliable, and well adapted for conventional chemical
processing equipment.
[0009] In one aspect, the present invention provides a polyester
polyol comprising the reaction product of:
[0010] A) an aromatic component comprising at 80 mole percent or
greater of terephthalic acid;
[0011] B) polyethylene glycol having a molecular weight from 150 to
1000; and
[0012] C) a glycol different from the glycol of B);
[0013] wherein A, B, and C are present in the reaction on a percent
weight bases of 20 to 60 weight percent A); 40 to 75 weight percent
of B); and 0 to 40 weight percent of C).
[0014] Another aspect of the invention provides a polyol blend,
suitable for use in preparing polymeric foams or elastomers
comprising urethane units. The polyols blends are particularly
useful in polyol formulations for rigid spray foam applications.
These blends comprise from 10 to 90 weight percent of an aromatic
polyester polyol as described above and the remainder is at least
one second polyol wherein the second polyols is a monol, a
polyether polyol or a combination thereof having a functionality of
2 to 8 and a molecular weight of 100 to 10,000.
[0015] In further embodiment, there is provided a sprayable blend
for making a rigid foam comprising urethane units. The rigid foam
made from a sprayable polyol blend is the reaction product of a
polyisocyanate and a polyol blend where the polyol blend comprises
30 to 60 weight percent of an aromatic polyester polyol of the
present invention and at least one second polyol having a
functionality of 2 to 6 and a hydroxyl number of 200 to 1,200. The
isocyanate index in preparing such rigid foams is from 90 to
400.
[0016] The present invention further provides for use of the
aromatic polyester polyols of the present invention as a viscosity
cutter for polyol formulations, particularly for sprayable polyol
formulations for producing rigid foam.
[0017] In a further aspect, the present invention provides a
reaction system for production a rigid foam comprising a polyol
composition comprising:
1) a polyol which is the reaction product of [0018] A) an aromatic
component comprising at 80 mole percent or greater of terephthalic
acid; [0019] B) polyethylene glycol having a molecular weight from
150 to 1000; and [0020] C) a glycol different from the glycol of
B);
[0021] wherein A, B, and C are present in the reaction on a percent
weight bases of 20 to 60 weight percent A); 40 to 75 weight percent
of B); and 0 to 40 weight percent of C);
2) a polyisocyanate and 3) optionally additives and auxiliaries
known per se. Such optional additives or auxiliaries are selected
from the groups consisting of dyes, pigments, internal mold release
agents, physical blowing agents, chemical blowing agents, fire
retardants, fillers, reinforcements, plasticizers, smoke
suppressants, fragrances, antistatic agents, biocides,
antioxidants, light stabilizers, adhesion promotors and combination
of these.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0022] The aromatic polyester polyols of the present invention are
prepared from a reaction mixture comprising A) terephthalic acid
and B) a at least one polyethylene glycol. In a further embodiment,
the reaction mixture may contain a further glycol, component C),
which is a glycol other than the polyethylene glycol. Such polyols
generally have nominal functionally of 2. To balance the properties
of aromatic based polyester polyols, it is desirable to have a
material with a low viscosity to allow for easy flow in commercial
applications and have a desired level of aromatic content in the
polyester. The present invention has found a combination of
polyethylene glycol with terephthalic acid gives an aromatic
polyester having a low viscosity while maintaining an acceptable
level of aromatic content in the polyester to maintain acceptable
properties of the final produced material.
[0023] While terephthalic acid generally gives enhanced flame
retardant properties to the final polyurethane product versus other
phthalic acid isomers, the use of terephthalic acid generally
increases the viscosity of the polyester. The use polyethylene
glycol, rather than diethylene glycol as commonly used to produce
aromatic polyester polyols, unexpectedly gives a low viscosity
polyol. The low viscosity polyester polyols allows the use of
terephthalic based materials in various end-use application.
[0024] The aromatic component (component A) of the present
polyester polyols is derived from terephthalic acid. The
terephthalic acid component will generally comprise 80 mole percent
or more of the aromatic content. In further embodiments,
terephthalic acid will comprise 85 mole percent or more of the
aromatic component. In another embodiment, terephthalic acid will
comprise 90 mole percent or more of the aromatic component for
making the aromatic polyester polyol. In another embodiment the
aromatic content comprises greater than 95 mole percent is derived
from terephthalic acid. In another embodiment the aromatic content
is essentially derived from terephthalic acid. While the polyester
polyols can be prepared from substantially pure terephthalic acid,
more complex ingredients can be used, such as the side-stream,
waste or scrap residues from the manufacture of terephthalic acid.
Recycled materials which can be broken down into terephthalic acid
and diethylene glycol, such as the digestion products of
polyethylene terephthalate may be used.
[0025] Component A) will generally comprise from 20 to 60 wt % of
the reaction mixture. In a further embodiment, component A)
comprise 25 wt % or greater of the reaction mixture. In a further
embodiment, component A) comprised 55 wt % or less of the reaction
mixture.
[0026] The polyethylene glycol, component B, is a polymer of
ethylene glycol and generally has a molecular weight of from 150 to
1,000. In one embodiment, the molecular weight is 160 or greater.
In a further embodiment the molecular weight is less than 800, less
than 600 or even less than 500. In a further embodiment the
molecular weight is less than 400.
[0027] The polyethylene glycol generally comprises from 30 to 80
weight percent of the reaction mixture. In further embodiment the
polyethylene glycol will comprise 35 weight percent or more of the
reaction mixture. In another embodiment the polyethylene glycol
will comprise 40 weight percent or more of the reaction mixture. In
another embodiment, the polyethylene glycol will comprise 75 weight
percent or less of the reaction mixture. In a further embodiment
the polyethylene glycol will comprise 70 weight percent or less of
the reaction mixture.
[0028] Polyethylene glycols are commercially available or may be
produced by the addition of ethylene oxide to a 2 functional
initiator by processes well known in the art.
[0029] While component B is described in terms of a polyethylene
glycol, polyglycols based on glycols containing greater than 2
carbon atoms may be used provided such polyglycols are within the
molecular weight as given for component B). Furthermore, it may be
possible to use glycols which contain secondary hydroxyl groups.
When using such glycols with secondary hydroxyl groups, it is
generally preferred to cap such polyols to give a primary hydroxyl,
i.e. capping with ethylene oxide, such that the polyglycol contains
greater than 75% primary hydroxyls.
[0030] In addition to the aromatic component A) and the
polyethylene component B), the reaction mixture may include a
glycol (component C) which is different from B). When used, such a
glycol, or blend of glycols, will generally have a nominal
functionality of 2 to 3. While component C) may have a glycol with
a functionality of greater than 3, to avoid an increase in the
viscosity of the material, it is generally preferred the
functionally of such a blend of glycols comprising component C)
will be 3 or less.
[0031] In one embodiment, the glycol of component C) may be
ethylene glycol, diethylene glycol, or an oxyalkylene glycol of the
formula:
##STR00001##
where R is hydrogen or a lower alkyl of 1 to 4 carbon atoms and n
is from 1 to 5 with the proviso that at least 10 percent of the R
moieties are a lower alkyl group. In a further embodiment n is 4 or
less. In a further embodiment n is 3 or less. In another
embodiment, all the R moieties will be a lower alkyl. In a further
embodiment R is a methyl group. Examples of such alkylene glycols
include propylene glycol and di-propylene glycol. In a further
embodiment, the glycol component C) will have an overall average
molecular weight of 180 or less. Examples of three functional
glycols include glycerin and trimethylolpropane.
[0032] When present, component C) will generally comprise greater
than 1 weight percent of the reaction mixtures. In a further
embodiment component C) will comprise 5 weight percent or greater
of component C) and my at least 10 weight percent of component C).
Generally when present, component C) will be less than 40 weight
percent of the reactions mixture. In further embodiments, less than
35 weight percent. In another embodiment, component C) will be less
than 30 weight percent of the reaction mixture.
[0033] When component C) is present, commercial products which
contain a crude blend of materials may be used to provide
components B) and C). For examples, production process may provide
for crude glycols which contain from 15-20 weight percent
diethylene glycol and the remainder triethylene and higher
glycols.
[0034] Based on the components in making the polyester, the
polyester will have a nominal functionality of two. When component
C) is present and comprises a glycol having 3 or more hydroxyl
groups, the aromatic polyester may have a nominal functionality of
greater than 2. In such circumstances, the functionality will
generally be less than 2.3. The amount of materials used in making
the polyester will generally provide for a polyester having a
hydroxyl number of from 200 to 400. In further embodiments the
hydroxyl number of the polyester is less than 350 and in a further
embodiment less than 300.
[0035] By inclusion of a specified amount of polypropylene glycol
and if desired, a second glycol as specified above, along with the
aromatic component, the viscosity of the resulting polyester is
generally less than 5,000 mPa*s at 25.degree. C. as measured by UNI
EN ISO 3219. In a further embodiment the viscosity of the polyester
polyol is less than 4,000 mPa*s. In other embodiments the viscosity
of the polyester polyol is 3,000 mPa*s or less. In yet another
embodiment the viscosity may be 2,500 mPa*s or less. In further
embodiments the viscosity is 2000 mPa*s or less. While it is
desirable to have a polyol with as low a viscosity as possible, due
to practical chemical limitations and end-use applications, the
viscosity of the polyol will generally be greater than 350
mPa*s.
[0036] An aromatic polyester polyol of the invention may include
any minor amounts of unreacted glycol remaining after the
preparation of the polyester polyol. Although not desired, the
aromatic polyester polyol can include up to about 40 weight percent
free diol. The free glycol content of the aromatic polyester
polyols of the invention generally is from about 0 to about 30
weight percent, and usually from 1 to about 25 weight percent,
based on the total weight of polyester polyol component. The
polyester polyol may also include small amounts of residual,
non-inter-esterified aromatic component. Typically the
non-inter-esterified materials will be present in an amount less
than 25 percent by weight based on the total weight of the
components combined to form the aromatic polyester polyols of the
invention.
[0037] The polyester polyols are formed by the
polycondensation/transesterification and polymerization of
component A and B, and if present component C under conditions well
known in the art. See for Example G. Oertel, Polyurethane Handbook,
Carl Hanser Verlag, Munich, Germany 1985, pp 54-62 and Mihail
Ionescu, Chemistry and Technology of Polyols for Polyurethanes,
Rapra Technology, 2005, pp 263-294. In general, the reaction is
done at temperature of 180 to 280.degree. C. In another embodiment
the reaction is done at a temperature of at least 200.degree. C. In
a further embodiment the reaction is done at a temperature of
215.degree. C. or greater. In a further embodiment the
transesterification is done at a temperature of 260.degree. C. or
less.
[0038] While the reaction may take place under reduced or increased
pressure, the reaction is generally carried out near atmospheric
pressure conditions.
[0039] While the reaction may take place in the absence of a
catalyst, catalysts which promote the
esterification/transesterification/polymerization reaction may be
used.
[0040] Examples of such catalysts include tetrabutyltitanate,
dibutyl tin oxide, potassium methoxide, or oxides of zinc, lead or
antimony; titanium compounds such as titanium (IV) isopropoxide and
titanium acetylacetonate. When used, such catalyst is used in an
amount of 0.05 to 1 weight percent of the total mixture. In further
embodiments the catalyst is present in an amount of from 0.1 to
0.75 weight percent of the total mixture.
[0041] The volatile product(s) of the reaction, for example water
and/or methanol, is generally taken off overhead in the process and
forces the ester interchange reaction to completion.
[0042] The reaction usually takes from one to five hours. The
actual length of time required varies, of course; with catalyst
concentration, temperature etc. In general, it is desired not to
have too long a polymerization cycle, both for economic reasons and
for the reason that if the polymerization cycle is too long,
thermal degradation may occur.
[0043] The polyesters of the present invention can be used as part
of a polyol formulation for making various polyurethane or
polyisocyanurate products. The polyol, also referred to as the
isocyanate-reactive component, along with an isocyanate component
make us a system for producing a polyurethane or polyisocyanurate.
The polyesters may be used as part of a formulation for making a
polyurethane and are particularly applicable in formulations for
producing rigid foam, spray foam application, appliance insulation,
elastomer formation, and various coatings, adhesives and sealant
formulation.
[0044] The polyesters of the present invention may be used alone or
can be blended with other known polyols to produce polyol blends.
Depending on the application, the polyester will generally range
from 10 to 90 wt % of the total polyol formulation. The amount
polyester polyols which can be used for particular applications can
be readily determined by those skilled in the art. For examples,
for formulations in rigid foam applications, the polyester can
generally comprise from up to 80 weight percent of the polyol
formulation. In other such embodiments, the polyester will comprise
less than 70 weight percent of the polyol formulation. In spray
formulations for rigid foam applications, the polyester will
generally be 60 weight percent or less of the polyol blend. When
preparing formulation for elastomer applications, the amount of
polyester used in such formulations may be from 10 to about 30
weight percent of the total formulation.
[0045] Representative polyols include polyether polyols, polyester
polyols different from the polyester of the present invention,
polyhydroxy-terminated acetal resins, and hydroxyl-terminated
amines. Alternative polyols that may be used include polyalkylene
carbonate-based polyols and polyphosphate-based polyols. Preferred
are polyether or polyester polyols. Polyether polyols prepared by
adding an alkylene oxide, such as ethylene oxide, propylene oxide,
butylene oxide or a combination thereof, to an initiator having
from 2 to 8 active hydrogen atoms. The functionality of polyol(s)
used in a formulation will depend on the end use application as
known to those skilled in the art. For example, typically polyols
suitable for preparing rigid polyurethanes include those having an
average molecular weight of 100 to 10,000 and preferably 200 to
7,000. Such polyols advantageously have a functionality of at least
2, preferably 3, and up to 8, preferably up to 6, active hydrogen
atoms per molecule. The polyols used for rigid foams generally have
a hydroxyl number of about 200 to about 1,200 and more preferably
from about 300 to about 800.
[0046] Monols may also be used as part of the polyol
formulation.
[0047] For the production of polyurethane elastomer, the
functionality of the polyol or polyol blend is generally from 1.8
to 2.2. The average functionality of the polyol blend does not
include any chain extenders or cross-linkers which may be included
in a formulation. The average equivalent weight of the polyol or
polyol blend for producing elastomer is generally from 500 to
3,000, preferably from 750 to 2,500 and more preferably from 1,000
to 2,200.
[0048] Polyether polyols are made by processes will known in the
art. Catalysis for this polymerization of the alkylene oxide can be
either anionic or cationic, with catalysts such as KOH, CsOH, boron
trifluoride, or a double cyanide complex (DMC) catalyst such as
zinc hexacyanocobaltate or quaternary phosphazenium compound.
[0049] Polyols that are derived from renewable resources such as
vegetable oils or animal fats can also be used as additional
polyols. Examples of such polyols include castor oil,
hydroxymethylated polyesters as described in WO 04/096882 and WO
04/096883, hydroxymethylated polyols as described in U.S. Pat. Nos.
4,423,162; 4,496,487 and 4,543,369 and "blown" vegetable oils as
described in US Published Patent Applications 2002/0121328,
2002/0119321 and 2002/0090488.
[0050] Suitable polyisocyanates for producing polyurethane products
include aromatic, cycloaliphatic and aliphatic isocyanates. Such
isocyanates are well known in the art.
[0051] Examples of suitable aromatic isocyanates include the 4,4'-,
2,4' and 2,2'-isomers of diphenylmethane diisocyante (MDI), blends
thereof and polymeric and monomeric MDI blends, toluene-2,4- and
2,6-diisocyante (TDI) m- and p-phenylenediisocyanate,
chlorophenylene-2,4-diisocyanate, diphenylene-4,4'-diisocyanate,
4,4'-diisocyanate-3,3'-dimethyldiphenyl,
3-methyldiphenyl-methane-4,4'-diisocyanate and
diphenyletherdiisocyanate and 2,4,6-triisocyanatotoluene and
2,4,4'-triisocyanatodiphenylether.
[0052] A crude polyisocyanate may also be used in the practice of
this invention, such as crude toluene diisocyanate obtained by the
phosgenation of a mixture of toluene diamine or the crude
diphenylmethane diisocyanate obtained by the phosgenation of crude
methylene diphenylamine. In one embodiment, TDI/MDI blends are
used.
[0053] Examples of aliphatic polyisocyanates include ethylene
diisocyanate, 1,6-hexamethylene diisocyanate, 1,3- and/or
1,4-bis(isocyanatomethyl)cyclohexane (including cis- or
trans-isomers of either), isophorone diisocyanate (IPDI),
tetramethylene-1,4-diisocyanate, methylene
bis(cyclohexaneisocyanate) (H.sub.12MDI), cyclohexane
1,4-diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, saturated
analogues of the above mentioned aromatic isocyanates and mixtures
thereof.
[0054] Derivatives of any of the foregoing polyisocyanate groups
that contain biuret, urea, carbodiimide, allophonate and/or
isocyanurate groups can also be used. These derivatives often have
increased isocyanate functionalities and are desirably used when a
more highly crosslinked product is desired.
[0055] For production of rigid polyurethane or polyisocyanurate
materials, the polyisocyanate is generally a
diphenylmethane-4,4'-diisocyanate,
diphenylmethane-2,4'-diisocyanate, polymers or derivatives thereof
or a mixture thereof. In one preferred embodiment, the
isocyanate-terminated prepolymers are prepared with 4,4'-MDI, or
other MDI blends containing a substantial portion or the
4,4'-isomer or MDI modified as described above. Preferably the MDI
contains 45 to 95 percent by weight of the 4,4'-isomer.
[0056] The isocyanate component may be in the form of isocyanate
terminated prepolymers formed by the reaction of an excess of an
isocyanate with a polyol or polyester, including polyester of the
present invention.
[0057] The polyesters of the present invention may be used for the
production of hydroxyl terminated prepolymers formed by the
reaction of an excess of the polyester with an isocyanate.
[0058] The polyisocyanate is used in an amount sufficient to
provide an isocyanate index of from 80 to 600. Isocyanate index is
calculated as the number of reactive isocyanate groups provided by
the polyisocyanate component divided by the number of
isocyanate-reactive groups in the polyurethane-forming composition
(including those contained by isocyanate-reactive blowing agents
such as water) and multiplying by 100. Water is considered to have
two isocyanate-reactive groups per molecule for purposes of
calculating isocyanate index. A preferred isocyanate index is from
90 to 400. For rigid foam and elastomer applications, the
isocyanate index is generally from is from 100 to 150. For
polyurethane-polyisocyanurate products, the isocyanate index will
generally be greater than 150.
[0059] It is also possible to use one or more chain extenders in
the formulation for production of polyurethane products. The
presence of a chain extending agent provides for desirable physical
properties, of the resulting polymer. The chain extenders may be
blended with the polyol component or may be present as a separate
stream during the formation of the polyurethane polymer. A chain
extender is a material having two isocyanate-reactive groups per
molecule and an equivalent weight per isocyanate-reactive group of
less than 400, preferably less than 300 and especially from 31-125
daltons. Crosslinkers may also be included in formulations for the
production of polyurethane polymers of the present invention.
"Crosslinkers" are materials having three or more
isocyanate-reactive groups per molecule and an equivalent weight
per isocyanate-reactive group of less than 400. Crosslinkers
preferably contain from 3-8, especially from 3-4 hydroxyl, primary
amine or secondary amine groups per molecule and have an equivalent
weight of from 30 to about 200, especially from 50-125.
[0060] For producing a polyurethane based elastomer, amounts of
crosslinkers generally used are from about 0.1 to about 1 part by
weight, especially from about 0.25 to about 0.5 parts by weight,
per 100 parts by weight of polyols.
[0061] To obtain adequate curing rates, a catalyst may be included
within the polyol component. Suitable catalysts include the
tertiary amine and organometallic compounds such as described in
U.S. Pat. No. 4,495,081. When using an amine catalyst
advantageously it is present in from 0.1 to 3, preferably from 0.1
to 1 and more preferably from 0.4 to 0.8 weight percent by total
weight of polyol and optional chain extending agent. When the
catalyst is an organometallic catalyst, advantageously it is
present in from 0.001 to 0.2, preferably from 0.002 to 0.1 and more
preferably from 0.01 to 0.05 weight percent by total weight of
polyol and optional chain extending agent. Particularly useful
catalysts include in the case of amine catalysts;
triethylenediamine, bis(N,N-dimethylaminoethyl)ether and
di(N,N-dimethylaminoethyl)amine and in the case of the
organometallic catalysts; stannous octoate, dibutyltin dilaurate,
and dibutyltin diacetate. Combinations of amine and organometallic
catalysts advantageously may be employed.
[0062] The polyesters of the present invention are particularly
suitable for use in applications where it is desired to have flame
retardant properties provided by the aromatic content. The low
viscosity of the polyols renders them suitable for use in rigid
spray insulation foam. The low viscosity is also suitable for
producing isocyanate terminated prepolymers where a low viscosity
is desired. The polyols may also be used as a viscosity reducing
additive in conventional polyol formulations.
[0063] Blowing agents used in polyurethane-forming composition are
known in the art and include physical blowing agents such as a
hydrocarbon, hydrofluorocarbon, hydrochlorofluorocarbon,
fluorocarbon, dialkyl ether or fluorine-substituted dialkyl ethers,
or a mixture of two or more thereof. It is generally preferred to
further include water in the formulation, in addition to the
physical blowing agent. In many polyol formulations, a physical
blowing can act as a viscosity cutter. An advantage of the low
viscosity polyester of the present invention is it may allow for
greater variation in polyol formulations as there is a reduced need
to rely on the physical blowing to modify system viscosity.
[0064] Blowing agent(s) are generally used is used in an amount
ranging from about 10 to about 40, preferably from about 12 to
about 35, parts by weight per 100 parts by weight polyol(s). Water
reacts with isocyanate groups to produce carbon dioxide, which acts
as an expanding gas. Water is suitably used in an amount within the
range of 0.5 to 7.5, preferably from 1.5 to 5.0 parts by weight per
100 parts by weight of polyol(s). In further embodiments the amount
of water will be from 1.5 to 3.5 parts by weight per 100 parts by
weight of polyol(s).
[0065] In addition to the foregoing ingredients, the
polyurethane-forming composition may include various auxiliary
components, such as surfactants, fillers, colorants, odor masks,
flame retardants, biocides, antioxidants, UV stabilizers,
antistatic agents, viscosity modifiers, and the like known in the
art.
[0066] Examples of suitable flame retardants include phosphorus
compounds, halogen-containing compounds and melamine.
[0067] Examples of fillers and pigments include calcium carbonate,
titanium dioxide, iron oxide, chromium oxide, azo/diazo dyes,
phthalocyanines, dioxazines, recycled rigid polyurethane foam and
carbon black.
[0068] Examples of UV stabilizers include hydroxybenzotriazoles,
zinc dibutyl thiocarbamate, 2,6-ditertiarybutyl catechol,
hydroxybenzophenones, hindered amines and phosphites. Except for
fillers, the foregoing additives are generally used in small
amounts, such as from 0.01 percent to 3 percent each by weight of
the polyurethane formulation. Fillers may be used in quantities as
high as 50% by weight of the polyurethane formulation.
[0069] The polyurethane-forming composition is prepared by bringing
the various components together under conditions such that the
polyol(s) and isocyanate(s) react, the blowing agent generates a
gas, and the composition expands and cures. All components (or any
sub-combination thereof) except the polyisocyanate can be
pre-blended into a formulated polyol composition, if desired, which
is then mixed with the polyisocyanate when the foam is to be
prepared.
[0070] For preparation of solid or microcellular polyurethane
polymers, such a polymer is typically prepared by intimately mixing
the reaction components at room temperature or a slightly elevated
temperature for a short period and then pouring the resulting
mixture into an open mold, or injecting the resulting mixture into
closed mold, which in either case is heated. The mixture on
reacting out takes the shape of the mold to produce a polyurethane
polymer of a predefined structure, which can then when sufficiently
cured be removed from the mold with a minimum risk of incurring
deformation greater than that permitted for its intended end
application.
[0071] It should be understood that the present description is for
illustrative purposes only and should not be construed to limit the
scope of the present invention in any way. Thus, those skilled in
art will appreciate that various modifications and alterations to
the presently disclosed embodiments might be made without departing
from the intended spirit and scope of the present invention.
Additional advantages and details of the present invention are
evident upon an examination of the following examples and appended
claims.
[0072] The following examples are provided to illustrate the
invention, but are not intended to limit the scope thereof. All
parts and percentages are by weight unless otherwise indicated.
[0073] A description of the raw materials used in the examples is
as follows. [0074] VORANOL* CP 450 is a glycerin initiated
polyoxypropylene polyol having a molecular weight of about 450.
[0075] VORANOL CP-1421 is a glycerin initiated
polyoxyethylene-polyoxypropylene mixed feed polyol having a
hydroxyl number of about 33, polyol available from The Dow Chemical
Company under the trade designation VORANOL CP-1421. [0076] VORANOL
RH 360 is a sucrose/glycerine initiated polyoxypropylene polyol
having a functionality of about 4.6 and hydroxyl number of about
360, available from The Dow Chemical Company under the tradename
Voranol RH 360. [0077] VORANOL P1010 is a glycerin initiated
polyoxypropylene polyol having a molecular weight of about 1000.
[0078] VORANOL P400 is a glycerin initiated polyoxyethylene polyol
having a molecular weight of about 400. [0079] DABCO DC 5598 is a
silicone surfactant available from Air Products. (DABCO is a
trademark of Air Products Corporation). [0080] Empilan NP-9 is a
non-ionic ethoxylated nonyl phenol surfactant. [0081] Simulsol TOGE
is a polyether polyol having a reported hydroxyl value of 900 and
functionality of 3, obtained from Seppic Inc. [0082] TERCAROL* 5902
is an aromatic diamine initiated polyether
polyoxypropylene-polyoxyethylene (36%) polyol having a hydroxyl
number of 340 to 400, functionality of about 3.5, available from
The Dow Chemical Company under the tradename TERCAROL 5902. [0083]
*VORANOL and TERCAROL are trademarks of The Dow Chemical Company.
[0084] Stepanpol PS 3152 is a diethylene glycol-phthalic anhydride
based polyester polyol having a hydroxyl value of 290 to 325 and
functionality of 2, obtained from Stepan Company. [0085] DMEA is
dimethylethanolamine (amine catalyst?). [0086] DMCHA is
N,N-Dimethylcyclohexylamine
[0087] Production of Polyester 1. Diethylene glycol (289.5 g),
polyethylene glycol 200 (1800 g) and terephthalic acid (910.5 g)
are charged to a 5000 ml glass flask equipped with a nitrogen inlet
tube, pneumatic stirrer, thermometer and condenser. Heat is applied
and the flask contents raised to 230-235.degree. C. At a
temperature of 220.degree. C. a titanium acetylacetonate catalyst
(Tyzor AA-105 from Du Pont) is charged (0.15 g) and a little flow
of nitrogen is applied. The mixture is held at 230-235.degree. C.
for 5 hours. The polyester polyol at this point has an acid No.
below 0.5 mgKOH/g. The content of the flask is cooled to room
temperature under atmospheric conditions.
[0088] Reference Polyester. Into the apparatus described for
Polyester 1 is added diethylene glycol (1820 g), and terephthalic
acid (1680 g). The process for production the control polyester is
as given for the production of Polyester 1.
[0089] The properties of Polyester 1 and the control polyester are
given in Table 1.
TABLE-US-00001 TABLE 1 Polyester specifications Polyester 1 Control
Acid value (mgKOH/g) 0.4 0.3 OH number (mgKOH/g) 240 241 Viscosity
at 25.degree. c. mPa * s 1200 15000 Physical state at 25.degree. c.
Liquid Solid after 1 week
[0090] The results show the polyester prepared using polyethylene
glycol has a substantially lower viscosity than the control
polyester prepared using diethylene glycol.
Example 1
[0091] Polyester 1 prepared as described above is used in
formulations to prepare rigid polyisocyanurate insulation for
discontinuous panels, using a high pressure machine (Cannon A40). A
control formulation uses Terate 4026 polyester polyol (from
Invista), an aromatic polyester polyol having a hydroxyl number of
about 205 and a viscosity of approximately 2500 mPa*s @ 25.degree.
C. The formulated polyols are given in Table 1.
TABLE-US-00002 TABLE 2 C1 1 Voranol CP-1421 8.2 8.2 Tercarol 5902
11.6 11.6 Terate 4026 52.8 Polyester 1 52.8 TCPP 10.2 10.2 (Tris
chloroisopropyl phosphate) TEP (Triethyl Phosphate) 6.8 6.8 Diethyl
Ethyl Phosphonate 5.8 5.8 DMCHA 0.3 0.3 Enpilan NP-9 2.3 2.3 DC
5598 silicone 1.7 1.7 Water 0.3 0.3 Total % 100 100
[0092] The formulated polyols are combined with other additives and
isocyanate M-600 given in Table 3. M-600 is a polymethylene
polyphenylisocyante, available from The Dow Chemical Company,
having an isocyanate content of about 30.3% and an average
functionality of 2.85.
TABLE-US-00003 TABLE 3 C1 1 Formulated polyol 100 100 Catalyst* 3.2
3.2 Bowing agent Additive** 5.5 5.5 n-pentane 9.7 9.7 M-600 225 225
Isocyanate index 1.9 1.9 *Catalyst system containing potassium
acetate (DABCO K 2097 from Air Products) **Formic acid
formulation
[0093] The properties of the foaming process and resulting foam are
given in Table 4.
TABLE-US-00004 TABLE 4 C1 1 Reactivity* CT (s) 5 5 GT (s) 48 45
Tack Free Time (s) 66 56 FRD 30 min (Kg/m3) 37.1 37.8 GREEN COMP
STRENGTH.sup.2 3 min (Kpa) 106.3 156 4 min (Kpa) 123.5 164.8 5 min
(Kpa) 136.1 177.5 Foam density, Jumbo mold at 45.degree. C. Density
(Kg/m3).sup.4 41.7 42.6 Friability.sup.3 (final weight-initial
weight) Vinitial wg .times. 100% DIN 4102 B2 core Measurement of 5
samples (mm) 8, 7, 6, 7, 7 6, 6, 6, 6, 6 Average (mm) 7 6 *CT and
GT are respectively cream time and gel time as measured in seconds.
FRD is free rise density. .sup.2Compressive strength is measured
according to UNI6350. .sup.3Friability is measured according to
ASTM C421. .sup.4Density measured by ASTM D 1622.
[0094] The data indicates the foam produced with the polyesters of
the present invention are capable of meeting the B2 test.
Example 2
[0095] Polyester 1 is used in formulations for the production of
elastomers as given in Table 5. For the production elastomers, it
is generally preferred to have a high Tg of the final elastomer to
avoid deformation/stress at high temperatures. The comparative
utilizes the aromatic polyester Stepanpol PS 3152.
TABLE-US-00005 TABLE 5 Examples Raw Materials C2 2 3 StephanPol PS
3152 34.5 -- -- Polyester 1 -- 34.5 47.5 Voranol P1010 16.2 16.2 7
Voranol P400 14.3 14.3 9 Voranol CP 450 8.5 8.5 13 Voranol RH 360
8.5 8.5 6.5 Tercarol 5902 10 10 8 Voranol RA 640 6 6 6 Simulsol
TOGE 2 2 3 Total 100 100 100 Tg*(.degree. C.) 74 66.28 73.66 *Tg is
measured by differential scanning calorimetry (DCS) analysis using
TA Instrument DSC Q200. Experimental conditions: temperature ramp
from 25.degree. C. to 180.degree. C. at 10.degree. C./min; nitrogen
atmosphere flow at 50 ml/min; pan Aluminium TZero Hermetic. Samples
are cooled back to 25.degree. C. at 10.degree. C./min and then
again heated to 180.degree. C. with a 10.degree. C./min ramp.
[0096] The results indicated the polyester of the present
invention, although having a lower aromatic content than the
polyester, due the low viscosity, can be used in higher levels in
formulations giving a product with Tg properties similar to a
control.
[0097] Other embodiments of the invention will be apparent to those
skilled in the art from a consideration of this specification or
practice of the invention disclosed herein. It is intended that the
specification and examples be considered as exemplary only, with
the true scope and spirit of the invention being indicated by the
following claims.
* * * * *