U.S. patent application number 09/832554 was filed with the patent office on 2003-01-30 for benzoate/alkanoate ester compositions.
Invention is credited to Arendt, William David, Bohnert, Thomas Joseph, Lang, Jiamin, Stanhope, Bruce Edward.
Application Number | 20030023112 09/832554 |
Document ID | / |
Family ID | 25261992 |
Filed Date | 2003-01-30 |
United States Patent
Application |
20030023112 |
Kind Code |
A1 |
Lang, Jiamin ; et
al. |
January 30, 2003 |
Benzoate/alkanoate ester compositions
Abstract
Mixtures of esters produced by reacting an aromatic and an
aliphatic monocarboxylic acid with a stoichiometric quantity of a
diol are effective plasticizers for polyvinyl chloride and other
rigid organic polymers. The freezing point of the mixtures and the
efficacy of the present ester mixtures as plasticizers can be
varied by adjusting the type and molar ratio of the two types of
acids used to prepare the ester mixture.
Inventors: |
Lang, Jiamin; (Arlington
Heights, IL) ; Stanhope, Bruce Edward; (Grayslake,
IL) ; Bohnert, Thomas Joseph; (Palatine, IL) ;
Arendt, William David; (Libertyville, IL) |
Correspondence
Address: |
Velsicol Chemical Corporation
Attn: Law Department
Suite 600
10400 W. Higgins Road
Rosemont
IL
60018
US
|
Family ID: |
25261992 |
Appl. No.: |
09/832554 |
Filed: |
April 11, 2001 |
Current U.S.
Class: |
560/90 |
Current CPC
Class: |
C08K 5/103 20130101;
C07C 69/78 20130101; C08K 5/103 20130101; C08L 27/06 20130101 |
Class at
Publication: |
560/90 |
International
Class: |
C07C 069/76 |
Claims
That which is claimed is:
1. An ester composition comprising 1) an ester corresponding to
formula (I) R.sup.1C(O)OR.sup.2O(O)CR.sup.3 I 2) an ester
corresponding to formula (II) R.sup.1C(O)OR.sup.2O(O)CR.sup.1; II
and 3)an ester corresponding to formula (III)
R.sup.3C(O)OR.sup.2O(O)CR.sup.3 III wherein R.sup.1 is at least one
radical selected from the group consisting of phenyl and
alkyl-substituted phenyl, R.sup.2 is a divalent radical of the
formula --R.sup.4(OR.sup.4).sub.m--, R.sup.3 is an alkyl radical
containing from 3 to 21 carbon atoms, R.sup.4 is an alkyl radical
containing from 2 to 4 carbon atoms, and m represents 0 or the
integer 1 or 2.
2. A composition according to claim 1 wherein the molar ratio of
R.sup.1C(O)-- to R.sup.3C(O)-- groups in said composition is at
least 1:1 and said composition is a liquid at 25.degree. C.
3. A composition according to claim 2 wherein said molar ratio is
from 1:1 to 12:1.
4. A composition according to claim 3 wherein said composition
additionally contains at least one ester exhibiting a formula
selected from the group consisting of R.sup.1C(O)OR.sup.2OH and
R.sup.3C(O)OR.sup.2OH.
5. A composition according to claim 1 wherein R.sup.1 is phenyl, m
is 1 or 2 and R.sup.3 contains from 8 to 16 carbon atoms.
6. A composition according to claim 5 wherein R.sup.4 is ethyl or
propyl and R.sup.3 contains 11 carbon atoms.
7. A plasticized polymer composition comprising 1) a polymer
selected from the group consisting of homopolymers and copolymers
of vinyl chloride and 2) a plasticizer comprising 1) an ester
corresponding to formula (1) R.sup.1C(O)OR.sup.2O(O)CR.sup.3 I 2)
an ester corresponding to formula (II)
R.sup.1C(O)OR.sup.2O(O)CR.sup.1; II and 3) an ester corresponding
to formula (III) R.sup.3C(O)OR.sup.2O(O)CR.sup.3 III wherein
R.sup.1 is at least one radical selected from the group consisting
of phenyl and alkyl-substituted phenyl, R.sup.2 is a divalent
radical of the formula --R.sup.4(OR.sup.4).sub.m--, R.sup.3 is an
alkyl radical containing from 3 to 21 carbon atoms, R.sup.4 is an
alkyl radical containing from 2 to 4 carbon atoms, and m represents
0 or the integer 1 or 2.
8. A polymer composition according to claim 7 wherein the molar
ratio of R.sup.1C(O)-- to R.sup.3C(O)-- groups in said composition
is at least 1:1, and said composition is a liquid at 25.degree.
C.
9. A polymer composition according to claim 8 wherein said molar
ratio is from 1:1 to 12:1.
10. A polymer composition according to claim 7 wherein R.sup.1 is
phenyl and m is 1 or 2 and R.sup.3. contains from 8 to 16 carbon
atoms.
11. A polymer composition according to claim 10 wherein R.sup.4 is
ethyl or propyl and R3 contains 11 carbon atoms.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to novel ester compositions. More
particularly, this invention relates to mixtures comprising 1) the
diester of a diol containing from 2 to 6 carbon atoms and benzoic
acid or a substituted benzoic acid, 2) a mixed ester of said diol,
said acid and an aliphatic monocarboxylic acid and, 3) a diester of
said diol and said aliphatic monocarboxylic acid. Small
concentrations of the monoester of 1) said diol and 2) said
aromatic and/or aliphatic carboxylic acids can also be present.
[0003] Preferred ester compositions of this invention are low
viscosity liquids at 25.degree. C., are considerably less volatile
and lower melting than the corresponding benzoic acid diesters, and
are effective primary plasticizers for rigid halogen-containing
organic polymers such as polyvinyl chloride.
[0004] 2. The Prior Art
[0005] Many esters of organic acids are known to be useful
plasticizers for a variety of organic polymers. Esters of 1)
monohydric alcohols and phthalic acid and 2) mono- or dihydric
alcohols and benzoic acid are particularly preferred plasticizers
for vinyl chloride homopolymers and copolymers based on their cost
and performance.
[0006] While esters of mono- or dihydric alcohols and aliphatic
monocarboxylic acids containing eight or more carbon atoms lower
the viscosity and impart low temperature flexibility to vinyl
chloride polymers, the incompatibility of the aliphatic acid esters
with these polymers limits their utility to secondary plasticizers
in combination with benzoic or phthalic acid esters as the primary
plasticizer. A disadvantage of this approach is that the
plasticizers selected may not be compatible with one another and/or
with the vinyl chloride or other polymer to which the ester mixture
will be added as a plasticizer.
[0007] A second approach to combining the advantages of aliphatic
and aromatic acids as plasticizers is to prepare a mixed ester.
This can be done by first forming a half ester by reacting a
dihydric alcohol, hereinafter referred to as a diol, with half a
molar equivalent of one of the monocarboxylic acids or a suitable
derivative thereof, such as the corresponding acid halide. The
resultant half ester is then isolated and reacted with the other
acid or a derivative thereof. The final ester can be represented by
the generic formula R'C(O)ORO(O)CR", where R represents the
hydrocarbon portion of a diol, R' represents the hydrocarbon
portion of the aromatic monocarboxylic acid and R" the hydrocarbon
portion of the aliphatic monocarboxylic acid.
[0008] The performance as plasticizers for polyvinyl chloride of
benzoate/alkanoate mixed esters of the aliphatic diols ethylene
glycol, diethylene glycol and 2-butene-1,4-diol is described by A.
V. Bailey et al. in the Journal of the American Oil Chemists
Society, 53 (5):176-8 (1976). The esters were obtained by first
reacting the desired diol with benzoyl chloride and then reacting
the resultant half ester with the acid chloride of desired
aliphatic acid. These acids contained from 5 to 20 carbon
atoms.
[0009] Bailey et al. report that the benzoate/laurate mixed ester
of diethylene glycol exhibits an optimum combination of properties
as a plasticizer, one of the reasons being that the other
plasticizers evaluated were incompatible with polyvinyl chloride at
concentration of 35 weight percent, based on the total weight of
the polymer composition.
[0010] The mixed esters utilized by Bailey et al. are pure
materials that require the two-stage preparation described in the
preceding paragraphs using acid chlorides rather than the
corresponding and relatively less expensive carboxylic acids.
[0011] The present invention is based on the discovery that useful,
relatively inexpensive mixtures of aromatic and aliphatic acid
esters can be prepared using a single step process. These ester
compositions are useful primary plasticizers for homo- and
copolymers of vinyl chloride and other rigid organic polymers.
[0012] In accordance with the present process a diol is reacted
with a stoichiometric amount of a mixture of 1) benzoic acid or
other aromatic monocarboxylic acid and 2) an aliphatic
monocarboxylic acid. The molar ratio of the two carboxylic acids is
adjusted to achieve the desired ratio of the two acid residues in
the reaction product. The molar ratio of total acids to diol is
typically 2:1.
[0013] The present ester compositions are considerably easier and
less expensive to prepare than the pure aromatic/aliphatic mixed
esters of the prior art and exhibit unexpectedly low levels of
viscosity and volatility. Other advantages of the present ester
compositions will be described in the present specification.
DETAILED DESCRIPTION OF THE INVENTION
[0014] This invention provides ester compositions comprising
[0015] 1) an ester corresponding to formula (I)
R.sup.1C(O)OR.sup.2O(O)CR.sup.3; I
[0016] 2) an ester corresponding to formula (II)
R.sup.1C(O)OR.sup.2O(O)CR.sup.1; II
and
[0017] 3) an ester corresponding to formula (III)
R.sup.3C(O)OR.sup.2O(O)CR.sup.3 III
[0018] wherein R' is at least one radical selected from the group
consisting of phenyl and alkyl-substituted phenyl, R.sup.2 is a
divalent radical of the formula --R.sup.4(OR.sup.4)m--, R.sup.3 is
an alkyl radical containing from 3 to 21 carbon atoms, R.sup.4 is
an alkyl radical containing from 2 to 4 carbon atoms, and m
represents 0 or the integer 1 or 2.
[0019] The present ester compositions are prepared by reacting a
diol of the formula HOR.sup.2OH with an aromatic monocarboxylic
acid of the formula R.sup.1C(O)OH and an aliphatic monocarboxylic
acid of the formula R.sup.3C(O)OH, wherein the total moles of said
aromatic and aliphatic carboxylic acids are equal to twice the
number of moles of said diol and R.sup.1, R.sup.2 and R.sup.3 are
as hereinbefore defined.
[0020] This invention also provides plasticized polymer
compositions comprising 1) a homopolymer or copolymer of vinyl
chloride and 2) a plasticizer comprising a mixed ester composition
of the present invention.
[0021] In preferred embodiments of the present ester compositions,
the molar ratio of R.sup.1C(O)-- to R.sup.3 C(O)-- groups in said
composition is from 3:1 to 12:1, R.sup.1 is phenyl, m is 1 or 2,
and the composition is a liquid at 25.degree. C.
[0022] The ester compositions of this invention can optionally
contain up to about 5 percent by weight of monoesters of the diol
HOR.sup.2OH and at least one of the aromatic and aliphatic
carboxylic acids used to prepare the ester. These monoesters are
represented in this specification by the formulae
R.sup.1C(O)OR.sup.2OH and R.sup.3C(O)OR.sup.2OH, wherein R.sup.1,
R.sup.2 and R.sup.3 are as previously defined. The presence of
these monoesters is typically not desirable because they increase
the volatility of the ester composition.
[0023] To minimize the concentration of monoesters in the final
ester mixture, the moles of aromatic and aliphatic acids used to
prepare the esters should be equal to twice the number of moles of
diol. The concentration of monoesters can be further reduced by
washing this mixture with an aqueous solution of a base such as
potassium hydroxide.
[0024] An unexpected advantage of the present ester compositions is
that by selecting preferred ranges for the molar ratio of the two
monocarboxylic acids and the number of carbon atoms in the
aliphatic carboxylic acid, the physical properties such as melting
point, viscosity and volatility exhibited by the resultant mixture
of esters and the compatibility of these mixtures with vinyl
chloride polymers can be varied over a wide range to achieve a
desired combination of properties. Preferred ester compositions and
the molar ratio of aromatic to aliphatic carboxylic acids used to
prepare them are described in subsequent sections of this
specification.
[0025] Although the relative concentrations of the three possible
diesters in a composition of the present invention is difficult to
predict, because carboxylic acids typically react at different
rates, the distribution of reaction products is influenced by the
relative concentrations of aromatic and aliphatic carboxylic acids
in the initial reaction mixture, the temperature of the reaction
mixture and the total reaction time.
[0026] The accompanying examples demonstrate that a reaction
mixture containing a 6:1 molar ratio of benzoic acid to the
aliphatic carboxylic acid will produce an ester mixture containing
a higher concentration of mono- and dibenzoates and a lower
concentration of the mixed benzoate/alkanoate ester than a reaction
mixture in which this molar ratio is 1:1. The inability to
precisely predict the relative concentrations of the possible mono-
and diesters in the present ester mixtures from the molar ratio of
the two carboxylic acids used to prepare them does not affect the
utility of the present mixtures as primary plasticizers for
polyvinyl chloride and other rigid organic polymers.
[0027] Preparation of the Mixed Esters
[0028] The mixed ester compositions of this invention can be
prepared by reacting the desired diol with a substantially
equimolar quantity of a mixture consisting essentially of 1) an
aromatic carboxylic acid selected from the group consisting of
benzoic acid and substituted benzoic acids and 2) an aliphatic
monocarboxylic acid containing from 3 to 21 carbon atoms.
Substituted benzoic acids such as toluic acid can be used in place
of benzoic acid. It will be understood by those skilled in the art
of ester preparation that derivatives of the aromatic and aliphatic
carboxylic acids, such as the corresponding acyl halides and acid
anhydrides, can be substituted for the acid.
[0029] While the molar ratio of the aromatic to the aliphatic
carboxylic acid and the particular aromatic and aliphatic acids
used to prepare the initial reaction mixture are not critical with
respect to operability of the process used to prepare the present
compositions, the molar ratio is preferably from 1 to 12 moles of
the aromatic monocarboxylic acid per mole of the aliphatic
monocarboxylic acid, the aromatic carboxylic acid is preferably
benzoic acid and the aliphatic carboxylic acid preferably contains
from 8 to 16 carbon atoms. These preferences are based on the
properties, particularly melting point and volatility, of the
resultant ester mixtures and the efficacy of the ester compositions
as plasticizers for vinyl chloride polymers.
[0030] Diols suitable for use in preparing the ester compositions
of the present invention can be represented by the general formula
HOR.sup.4(OR.sup.4).sub.mOH. In this formula R.sup.4 represents an
alkyl radical containing from 2 to 4 carbon atoms, and m represents
0 or the integer 1 or 2.
[0031] Suitable diols include but are not limited to ethylene
glycol, propylene glycol, 1,3-propanediol,
2-methyl-1,3-propanediol, diethylene glycol, dipropylene glycol,
triethylene glycol, 1,3-butanediol and 1,4-butanediol. Diols
wherein R.sup.4 is ethyl or n-propyl and m is 1 or 2 are preferred
based on their cost and commercial availability.
[0032] Because esterification is typically a reversible reaction,
this reaction is typically conducted at the boiling point of the
reaction mixture and the water produced as a by-product of the
reaction is preferably distilled from the reaction mixture and
collected. To increase the rate of the esterification reaction, it
is preferably conducted in the presence of a suitable catalyst such
as a mineral acid, an organotin compound, an organotitanium
compound and/or a zirconium compound. Suitable catalysts include
but are not limited to the organic sulfonic acids such as toluene
sulfonic acid, tin compounds such as stannous octoate, tetrabutyl
titanate and zirconium carbonate. These catalysts can be used alone
or in combinations of two or more.
[0033] The procedures and equipment used to prepare, isolate and
analyze the ester mixtures produced from the esterification
reaction are sufficiently well known to those skilled in this art
that a detailed discussion is not required as part of the present
specification. Gas chromatography is a preferred method for
determining the types and relative concentration of the esters in
the present compositions.
[0034] When equal numbers of moles of diethylene glycol, benzoic
acid and lauric acid were reacted and the resultant mixture of
esters treated with aqueous potassium hydroxide solution followed
by washings with water to reduce the concentration of monoesters,
analysis of the product using gas chromatography showed the mixture
to contain less than 0.5 percent diethylene glycol monobenzoate, 4
percent diethylene glycol monolaurate, 14 percent diethylene glycol
dibenzoate, 45 percent diethylene glycol monobenzoate monolaurate
and 36 percent diethylene glycol dilaurate, based on the relative
areas of the peaks on the output chart of the chromatograph.
[0035] Properties of Preferred Mixed Esters
[0036] Ester mixtures prepared by reacting benzoic acid and a
carboxylic acid containing from 9 to about 14 carbon atoms with one
of the present diols are preferred based on their unexpected
combination of properties that make these esters particularly
useful primary plasticizers for organic polymers such as
homopolymers and copolymers of vinyl chloride.
[0037] Data in the accompanying examples demonstrate that the
viscosity and freezing point of these esters are unexpectedly low
relative to the corresponding diester of benzoic acid. As the molar
ratio of benzoic acid to lauric acid in the initial reaction
mixture increases from 1:1 to 9:1 the freezing point of the
resultant ester mixture decreases from 25.degree. C. to a eutectic
point at about -15.degree. C. As this ratio increases beyond 9:1 to
the absence of the aliphatic carboxylic acid, the freezing point of
the resultant ester mixture increases to about 25.degree. C. for
diethylene glycol dibenzoate.
[0038] Performance of the Present Mixed Esters as Plasticizers
[0039] Mixed esters prepared from benzoic acid, an aliphatic
carboxylic acid containing from 8 to 16 carbon atoms and a diol
such as diethylene glycol are particularly useful plasticizers
based on the unique and unexpected combination of an unexpectedly
low freezing point and low volatility of the mixed ester and the
low viscosity and relatively low gel temperature of the plasticized
polymer. In addition to homo-and copolymers of vinyl chloride,
other types of polymers suitable for use with the present ester
compositions include but are not limited to thermoplastic polymers
such as cellulose ester polymers, polystyrene, and chloronated
polyethylene, and elastomers such as polyacrylics,
styrene/butadiene copolymers and natural rubber.
[0040] The following examples describe preferred embodiments of the
present ester mixtures, a preferred method for preparing them, the
physical properties of these mixtures and the properties of
polyvinyl chloride compositions containing these mixtures as
primary plasticizers. The examples should not be interpreted as
limiting the scope of the invention defined in the accompanying
claims. Unless otherwise specified all parts and percentages in the
examples are by weight and the physical properties of the esters
mixtures were measured at 25.degree. C.
EXAMPLE 1
[0041] Four mixed ester compositions of the present invention were
prepared by charging a glass reactor with diethylene glycol
(OHCH.sub.2CH.sub.2OCH.sub.2CH.sub.2OH) as the diol, benzoic acid
as the aromatic carboxylic acid, lauric acid as the aliphatic
carboxylic acid, and, as the catalyst for the esterification
reaction, 0.1 percent, based on the weight of total reactants, of a
catalyst mixture containing 75 weight percent zirconium carbonate
and 25 weight percent stannous oxalate. The molar ratio of benzoic
to lauric acids present in the four initial reaction mixtures is
listed in Table 1. The molar ratio of total carboxylic acids to
glycol was 2:1 in all of these reaction mixtures.
[0042] The reactor was equipped with a thermometer to measure the
temperature of the reaction mixture, a mechanically driven stirrer,
an inlet for nitrogen extending below the surface of the reaction
mixture, and a trap to collect the water that distilled as a
by-product of the esterfication reaction. A water-cooled reflux
condenser was located above the trap.
[0043] The contents of the reactor were gradually heated to liquify
the solid reactants and initiate vaporization of volatile
materials. At a reaction mixture temperature of about 180.degree.
C. all of the initial reactants had liquified and vaporized liquid
had begun to condense and collect in the trap. The boiling point of
the reaction mixture gradually increased to 250.degree. C.
Following about 4 hours of heating the acid number of the reaction
mixture was measured at 30 minute intervals until a value of 5 or
less was obtained. A small volume of diethylene glycol was added if
the acid number was greater than 5 and did not change between
successive samplings. When the acid number of the reaction mixture
measured 5 or less, heating of the reaction mixture was
discontinued and the mixture allowed to cool to 90.degree. C. At
this time a volume of a 10 weight percent aqueous potassium
hydroxide solution equal to about 1/3 the volume of the reaction
mixture was added to the reactor. After about 15 minutes of
stirring the aqueous layer was separated and discarded. The organic
layer was washed three times using volumes of 10 weight percent
aqueous potassium hydroxide solution equal to that used for the
first washing, followed by at least three washings with hot
deionized water until the pH of the organic layer was 7.
[0044] The types and relative concentrations of esters in the
reaction product, a clear, colorless liquid, was determined using a
Hewlett Packard HP6890 series gas chromatograph equipped with a
type HP-5 column packed with phenyldimethylpolysiloxane that was 5%
crosslinked. The column temperature was gradually increased from 80
to 320.degree. C. and the rate of helium flow was 200 cc. per
minute.
[0045] The chromatogram generated by passage of an ester mixture
through the detector of the gas chromatograph contained four or
five peaks, each corresponding to one of the component esters. The
area under a given peak was considered directly proportional to the
relative concentration of the corresponding ester. Under the
operating conditions of the chromatograph the esters emerged in the
following order: the monobenzoate of diethylene glycol (DEGMB), the
monolaurate (DEGML), the dibenzoate (DEGDB), the mixed
benzoate/laurate (DEGBL) and the dilaurate (DEGDL).
[0046] The molar ratio of benzoic acid to lauric acid used for each
of the four esterification reactions is recorded in Table 1,
together with the percent of total peak area on the chromatogram
corresponding to each of the aforementioned five possible products.
In each of the initial reaction mixtures the molar ratio of
diethylene glycol to total carboxylic acids was 1:2.
1TABLE 1 Benzoic Acid:Lauric Acid Mole Ratio.sup.1 % DEGMB.sup.2 %
DEGML % DEGDB % DEGBL % DEGDL 1:1 (DEGBL) <0.5 4 14 45 36 3:1
(DEG3BL) <0.5 <1 38 46 15 6:1 (DEG6BL) <0.5 <2 58 30 9
9:1 (DEG9BL) <0.5 <1 72 22 4 12:1 (DEG12BL) <0.5 <1 77
19 2 1 = All mole ratios refer to reactants 2 = All percentages
based on total reaction product
EXAMPLE 2
[0047] This example demonstrates the relatively low freezing point,
viscosity and volatility that make the present ester mixtures
desirable plasticizers for polyvinyl chloride and other rigid
organic polymers.
[0048] The freezing points of the esters mixtures described in
Example 1 that were liquid at ambient temperature were determined
by exposing the ester mixtures to a mixture of ethylene glycol and
water that was cooled to the desired temperature using a
refrigeration unit. The temperature of the mixture containing a
sample of the ester to be to be evaluated was initially 25.degree.
C. and was lowered in increments of 5.degree. C. Each temperature
level was maintained for 24 hours. The sample was examined at the
end of each 24-hour period to determine if the initially liquid
ester composition had solidified. The temperature at which solid
material was first observed was reported as the freezing point of
the ester mixture being evaluated and is recorded in Table 2. For
comparative purposes, pure diethylene glycol dibenzoate freezes at
25.degree. C.
[0049] The viscosities of the esters were measured at 25.degree. C.
using a stress-controlled rheometer manufactured by TA Instruments
and equipped with a 4 cm-diameter cone-shaped plate.
[0050] The esters are identified in the same manner as in the
preceding Table 1.
2TABLE 2 BENZOIC ACID/ LAURIC ACID MOLE RATIO FREEZING
TEMP.(.degree. C.) VISCOSITY @ 5.degree. C..sup.1 1:1 (DEGBL) 25
(Solid) 3:1 (DEG3BL) 5 0.13 6:1 (DEG6BL) -5 0.15 9:1 (DEG9BL) -15
0.18 12:1 (DEG12BL) -10 0.28 DEGDB.sup.2 25 0.43 (supercooled)
.sup.1= Viscosity in Pascal Seconds (Pa .multidot. s) .sup.2=
Diethylene glycol dibenzoate (evaluated for comparative purposes
and known to supercool)
[0051] The volatility of the esters was determined using a model
TGA2950 thermogravimetric analyzer manufactured by TA Instruments.
The percentage weight change was measured by exposing the sample to
a temperature of 190.degree. C. for 3 hours under a flow of
nitrogen at a rate of 100 cc. per minute. The percent weight loss
of each ester was determined at 30 minute intervals and the results
are recorded in Table 3. Di-2-ethylhexyl phthalate (DOP) was
evaluated for comparative purposes.
3 TABLE 3 % Weight Loss Time (Min.) DEGBL DEG3BL DEG6BL DEG9BL
DEGDB DOP* 0 0 0 0 0 0 0 30 9.8 11.4 14.5 11.2 28.7 18.1 60 20.6
23.3 28.0 23.1 53.0 37.1 90 29.8 32.6 37.2 33.5 71.0 56.1 120 37.8
41.1 47.1 42.9 83.4 76.0 150 44.7 48.7 58.0 51.0 92.1 90.4 180 50.7
55.4 64.5 60.0 100 95.7 *= Dioctyl Phthlate (Comparison)
[0052] The data in Tables 2 and 3 demonstrate the unexpectedly
lower volatility of DEG9BL relative to DEG6BL, which, in turn,
exhibited higher values than DEG3BL. This is an unexpected reversal
of the observed trend toward higher values of viscosity and
volatility with increasing benzoic acid content.
EXAMPLE 3
[0053] This example demonstrates the utility of the mixed esters of
this invention as plasticizers for polyvinyl chloride (PVC)
compositions. Preferred esters of the present invention exhibit a
unique combination of high solvating ability for the polymer with a
relatively low viscosity of the plasticized polymer
composition.
[0054] The ester compositions were incorporated into two plastisol
formulations. The plasticizer was used at levels of 30 and 55 parts
by weight per 100 parts of PVC resin(s).
[0055] The types and amounts of ingredients in the two formulations
evaluated are recorded in Table 4.
4 TABLE 4 Formulation A B Ingredient Parts Parts PVC 100 60
Blending 0 40 Resin Plasticizer 55 30 TXIB.sup.1 3 6 ESO.sup.2 4 4
Stabilizer.sup.3 3 3 .sup.1= Texanol .RTM. isobutyrate .sup.2=
Epoxidized Soybean Oil .sup.3= A calcium/zinc stabilizer available
as Irgastab CZ 116 from Witco Chemical Corporation
[0056] The polyvinyl chloride was prepared by microsuspension
polymerization and exhibited a weight average molecular weight of
200,000. It is available as Lacovyl PB 1302 from Atochem.
[0057] The blending resin was a vinyl chloride homopolymer prepared
by suspension polymerization, exhibited a weight average molecular
weight of 140,000, and is available as Vinnolit C65V from Wacker
Chemie. The purpose of the blending resin was to reduce the
viscosity of the plastisol.
[0058] Both of these polymers were in the form of finely divided
solids.
[0059] Plastisols were prepared by first blending the liquid
ingredients using a high speed mixer. The resultant mixture was
cooled using an ice/water bath to prevent gelation of the
composition during addition of the vinyl chloride polymer(s).
Following addition of the polymer(s) the composition was stirred at
a mixer speed of 1200 revolutions per minute for 10 minutes then
deaerated for 30 minutes under reduced pressure with stirring.
[0060] The viscosity of the resultant deaerated plastisols A and B
were measured using a stress-controlled rheometer manufactured by
TA Instruments. The spindle of the instrument was equipped with a
plate measuring 2 cm. in diameter. The shear rate was 10
sec..sup.-1 under ambient conditions.
[0061] The gelation temperatures of the plastisols were determined
using the same rheometer and 2 cm.-diameter plate used to determine
viscosity. In this instance the plate was oscillated rather than
rotated as in the case of the viscosity measurement. The
temperature of the metal block on which the sample of plastisol
rested was gradually increased until gelation of the plasticizer
occurred, which was evidenced by a sudden increase in the torque
required to oscillate the plate.
[0062] When changing the plasticizer in a plastisol results in a
lowering of the gelation temperature, this is associated with
greater solvating ability of the plasticizer. The viscosity and
gelation temperature of the plastisols evaluated are recorded in
Table 4.
[0063] Plastisols corresponding to formulations A and B but using
di2-ethylhexyl phthalate or a 1:1 weight ratio mixture of
diethylene glycol dibenzoate and triethylene glycol dibenzoate in
place of a mixed ester composition of the present invention were
prepared and evaluated for comparative purposes.
[0064] The viscosity and gelation temperature of the plastisols are
recorded in Table 4.
5 TABLE 4 Viscosity Gelation Temperature Plasticizer (Pa .multidot.
s) (.degree. C.) DEG3BL 1.1 67 DEG6BL 1.5 65 DEG9BL 1.6 65 DEGDB/
3.5 63 TEGDB.sup.1 DOP 1.8 76 .sup.1a 1:1 weight ratio mixture of
diethylene glycol dibenzoate and triethylene glycol dibenzoate used
for comparative purposes
[0065] The data in Table 4 demonstrate the unique combination of
low viscosity and increased solvating ability, as evidenced by a
lower gelation temperature, that distinguish preferred embodiments
of the present mixed esters relative to widely used plasticizers
for vinyl chloride polymers.
EXAMPLE 4
[0066] This example demonstrates the compatibility of the present
ester mixtures with polyvinyl chloride.
[0067] The plastisols to be evaluated were coated on release paper
and fused by heating at 200.degree. C. for 2 minutes. The resultant
sheets were about 1 mm. thick. Samples measuring 1.times.3 inches
(2.54.times.7.62 cm.) were cut from the sheets. The samples were
then removed from the paper backing and folded to form a U-shaped
loop, compressed within a binder clip, heated and then evaluated in
accordance with the procedure described in ASTM test D 3291-92. The
test samples were heated at 73.degree. C. for 24 hours. Following
heating the curved interior portion of each sample was daubed with
a cigarette paper to determine whether any plasticizer had exuded
from the polymer. The amount of exuded liquid was rated on a scale
of from 0 (no liquid present), to 3 (surfaces of polymer and paper
covered with continuous films of liquid exudate). All of the test
samples evaluated were rated "0" with the exception of the sample
containing 55 parts by weight of the mixed ester referred to in
Table 1 as DEG3BL. This sample was given a rating of "1",
indicating only slight exudation with faint, discontinuous marks on
the paper.
* * * * *