Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
1998-12-07
2001-02-06
Wu, David W. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S287000, C524S296000, C524S105000, C524S477000, C524S125000, C524S151000, C524S080000
Reexamination Certificate
active
06184278
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to liquid ester compositions. More particularly, this invention relates to mixtures of esters derived from certain aromatic monocarboxylic acids and specified combinations of oligomeric and optionally monomeric ethylene glycols. These mixtures are liquids at temperatures below the freezing point of the individual constituent esters.
DESCRIPTION OF THE PRIOR ART
Esters derived from 1) benzoic or toluic acid and 2) an aliphatic glycol or oligomer thereof together with methods for preparing these esters are described in the prior art.
Certain of these esters, particularly esters derived from glycols containing from 2 to about 9 carbon atoms, constitute a preferred class of plasticizers for polyvinyl chloride and other inherently rigid organic polymers because of the ability of the esters to improve the processability of the rigid polymers without adversely affecting their desirable physical properties.
U.S. Pat. No. 4,656,214, which issued to Wickson on Apr. 7, 1987 describes diesters of 1) linear glycols containing from 2 to 8 carbon atoms, 2) a first carboxylic acid of the formula R
1
R
2
R
3
C(O)OH and 3) a second carboxylic acid of the formula R
5
C(O)OH, wherein R
1
and R
2
are individually selected from alkyl containing from 1 to 4 carbon atoms, R
3
is hydrogen or alkyl from 1 to 6 carbon atoms, R
5
is selected from the group consisting of phenyl, mono- di- and trialkyl-substituted phenyl containing from 9 to 12 carbon atoms and —(CH
2
)
n
Ph where Ph is phenyl and the value of n is from 1 to 6, inclusive. The esters contain from 16 to 19 carbon atoms and are useful as stain-resistant plasticizers for polyvinyl chloride.
The use as plasticizers of esters derived from benzoic acid and a polyhydric alcohol is described in Japanese Laid Open Patent Application No. 54/18859, published on Feb. 13, 1979.
Published European Patent Application No. 244,107, issued on Nov. 4, 1987 describes plasticizer compositions for elastomers comprising I) a trimellitate ester, II) a saturated linear dicarboxylate ester obtained by reacting 1) a dicarboxylic acid with at least one monohydric alcohol or 2) an aliphatic monocarboxylic acid with at least one of diethylene glycol, triethylene glycol and tetraethylene glycol, and III) a dialkyl ester of a thiodicarboxylic acid.
U.S. Pat. No. 4,444,933 to J. Anderson and P. Columbus describes cyanoacrylate adhesives containing a plasticizer that is selected from dipropylene glycol dibenzoate, diethylene glycol dibenzoate, a mixture of the foregoing two compounds, butylbenzyl phthalate, dibutyl phthalate or a benzoate ester of di- or polyhydroxy branched aliphatic compounds.
Research Disclosure No. 17943, published on Mar. 10, 1979 describes plasticized road marking compositions containing from 10 to 50 weight percent of a plasticizer described as a benzoic acid ester exemplified by glyceryl tribenzoate, neopenyl dibenzoate, triethyleneglycol dibenzoate and trimethylolethane tribenzoate or a polyester.
Esters derived from benzoic acid and either di- or triethylene glycol are particularly desirable because of the wider availability and lower cost of these glycols relative to the corresponding propylene glycols. One of the disadvantages of using benzoic or toluic acid esters of ethylene glycol, di- and triethylene glycol as plasticizers is that these esters are solids at 25°. Polymer compositions containing these esters as additives typically require heating to at least the melting point of the additive to uniformly blend the additive into the composition.
SUMMARY OF THE INVENTION
The present invention is based on the discovery that within a relatively limited range of proportions blends containing the di- and triethylene glycol esters of benzoic and toluic (methylbenzoic) acids are liquids below the freezing point of the individual constituent esters.
When the present blends are used as plasticizers they can optionally include at least one additional ester that is a liquid at 25° C. and is conventionally used as a plasticizer for organic polymers. The additional liquid ester(s) increases the relative concentration of triethylene glycol ester relative to diethylene glycol ester that can be present in a composition that is liquid below the freezing points of both glycol esters.
DETAILED DESCRIPTION OF THE INVENTION
This invention provides liquid ester compositions comprising:
1) a first diester of the formula ArC(O) (OCH
2
CH
2
)
2
O(O) CAr and
2) a second diester of the formula ArC(O) (OCH
2
CH
2
)
3
O(O) CAr;
wherein Ar represents a phenyl or methylphenyl radical, and the freezing point of said compositions are below the freezing points said first and second diesters.
The weight ratio of said first diester to said second diester is preferably from 1.22:1 to 9:1.
In preferred embodiments the first and second diesters preferably constitute at least 50 weight percent of the present liquid ester composition. The remaining ingredients of these preferred embodiments are esters exhibiting freezing points below 250° C. These additional esters are derived from mono- or polyhydric alcohols and aromatic or aliphatic mono- and/or dicarboxylic acids. The presence of these additional liquid esters increases the concentration of the triethylene glycol diester relative to the diethylene glycol diester that can be present in compositions that are liquid below the freezing point of these glycol diesters.
Examples of the additional liquid esters that can be present in the ester compositions or the present invention include but are not limited to 1) diesters derived from benzoic acid and diols containing from 3 to 10 carbon atoms, 2) esters derived from benzoic acid and monohydric alcohols containing from 8 to 12 carbon atoms, 3) aliphatic esters of the formula R
1
O(O)C(CH
2
)
m
C(O)OR
1
, and 4) esters derived from phthalic acid and alcohols containing from 4 to 12 carbon atoms. In the preceding formula R
1
is an alkyl individually selected from the group consisting of alkyl and aryl radicals containing from 4 to 12 carbon atoms, and m represents an integer from 2 to 8. The combined weight of these additional plasticizers can constitute up to 50, and preferably from 10 to 35 weight percent of the present liquid ester composition. It will be understood that suitable diols can contain hetero atoms such as oxygen in the hydrocarbon chain.
Specific examples of additional liquid esters that can be present in the ester compositions of the present invention include but are not limited to propylene glycol and dipropylene glycol dibenzoates, neopentyl glycol dibenzoate, dialkyl adipates, glutarates, azelates and sebacates, isodecyl benzoate and butyl benzyl phthalate.
The additional liquid esters described in the preceding paragraphs can constitute up to 50 weight percent of the present liquid ester compositions. The presence of these optional liquid esters reduce to about 0.5:1 the weight ratio of the present diethylene glycol benzoate or toluate to triethylene glycol benzoate or toluate required to yield a liquid ester composition at 28° C.
The present invention also provides compositions comprising 1) an organic polymer such as polyvinyl chloride and 2) up to about 60 weight percent of the present liquid ester compositions as plasticizers. The ester compositions can also be included as plasticizing additives in liquid compositions such as oils and lubricants.
The novelty of the present ester compositions resides in the lower freezing point of the compositions relative to the freezing temperatures of the two required diesters that constitute at least 50 percent by weight of these compositions. For example, diethylene glycol dibenzoate freezes from 28-29° C., and triethylene glycol dibenzoate freezes from 46-48° C. Unexpectedly, all of the present ester compositions are liquids below 28° C. The actual freezing point of any specific ester composition will be determined by the relative concentrations of the constituent esters.
The Aromatic Carboxylic Acid
Aromatic carboxylic acids suitable for preparing the present liquid ester co
Arendt William David
Bohnert Thomas Joseph
Holt Mark Stephen
Abrams Hugh A.
Sidley & Austin
Velsicol Chemical Corporation
Wu David W.
Zalukaena Tanya
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