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
2000-12-20
2004-03-16
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...
C524S568000, C524S081000, C524S284000, C524S315000
Reexamination Certificate
active
06706806
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to polymeric plasticizers. More particularly, this invention relates to polyester type plasticizers wherein a portion of the repeating units are derived from diethylene glycol and at least one dicarboxylic acid.
2. Description of the Prior Art
Plasticizers are well known groups of chemical compounds useful for imparting flexibility, processability and other desirable properties to a variety of materials, including but not limited to organic polymers. Plasticizers are particularly useful for organic polymers that are inherently rigid and difficult to process. Widely used polymers of this type are derived at least in part from ethylenically unsaturated halogenated olefins including but not limited to vinyl- and vinylidene halides such as vinyl chloride and vinylidene chloride.
Desirable properties of plasticizers include efficiency, low permanence and compatibility. An efficient plasticizer will impart its desirable properties at a relatively low concentration, typically 50 weight percent or less, based on the total weight of the polymer composition.
Plasticizers are typically classified as monomeric or polymeric. Polymeric plasticizers are preferred for certain applications, because they are typically less volatile and less easily extracted by water, detergents, oil and organic solvents from polymers into which they have been incorporated. In addition to these desirable properties the plasticizer should be compatible with the polymer into which it is incorporated. Incompatibility typically appears as migration of the plasticizer to the surface of the polymer into which it has been incorporated. In addition to adversely affecting the appearance of the polymer and wetting surfaces in contact with the polymer, incompatibility between polymer and plasticizer typically results in a loss of desirable properties such as flexibility.
The preparation of polyesters from adipic acid, 1,2-propanediol and diethylene glycol is described by J. Wang et al. in Huaxue Shijie [(1998) 29(3), pp. 117-120. The use of these polyesters as plasiticizers for polyvinyl chloride or other polymers is not disclosed.
The use of liquid polyesters prepared using diethylene glycol and at least one dicarboxylic acid as polymeric plasticizers is reported in the literature. S. F. Zawadzki [Polym. -Plast. Technol. Eng. (1993) 32(1-2) pp.155-165] reports that although these polyesters are only slightly compatible with polyvinyl chloride, the plasticizing properties exhibited by these polyesters can be utilized by employing them as secondary plasticizers in combination with other known plasticizers for vinyl chloride polymers.
I. A. Sorokina [Plast. Massy (1975) 8, 25-7] reports that the poor compatibility with polyvinyl chloride of polyesters prepared using adipic acid and diethylene glycol can be improved by replacing the hydroxyl end groups of the polymer with —CH
2
CH
2
OC(O)C
n
H
2n+1
groups.
The use as plasticizers for polyvinyl chloride of copolymers prepared by reacting diethylene glycol, 1,3-butanediol and either adipic or phthalic acid is described by A. Abdel-Azim in Polymer International, 47 (1998) pp. 303-310.
Polymeric plasticizers prepared using blends of 1,2-propanediol (1) and 2-methylpropane-1,3-diol (2) and aliphatic dicarboxylic acids containing from 6 to 14 carbon atoms are described in U.S. Pat. No. 6,111,004, issued to Keith Biesiada et al. on Aug. 29, 2000. The molar ratios of (1) to (2) used to prepare the polymers is from 1:3 to 3:1 and the polymers contain from 1 to 12 repeating units per molecule.
The present inventors have discovered that a relatively broad class of difunctional alcohols can be used in combination with diethylene glycol and at least one dicarboxylic acid to prepare polyesters that are efficient yet economical primary plasticizers for homo- and copolymers prepared using halogenated olefins such as vinyl chloride.
Preferred embodiments of the present plasticizers exhibit improved physical properties, including low viscosity. Polymer compositions containing these plasticizers exhibit a higher surface energy, lower glass transition temperature and greater low temperature flexibility relative to compositions containing prior art polyesters as plasticizers.
SUMMARY OF THE INVENTION
This invention provides liquid polyester plasticizers, wherein the repeating units of said polyester comprise (I) —OCH
2
CH
2
OCH
2
CH
2
OC(O)R
1
(O)C—, and (II) —OR
2
OC(O)R
1
(O)C—, the terminal groups of said polyester are selected from the group consisting of hydrogen, —R
3
and —C(O)R
4
and are bonded to an oxygen atom, R
1
is at least one member selected from the group consisting of a single bond, alkylene containing from 1 to 20 carbon atoms, cycloalkylene, and ortho-, meta- and para-phenylene; R
2
is at least one member selected from the group consisting of alkylene, cycloalkylene and oxyalkylene radicals, wherein said alkylene and oxyalkylene radicals contain from 2 to 8 carbon atoms with the proviso that R
2
is not —CH
2
CH
2
OCH
2
CH
2
— or —CH
2
CH
2
CH(CH
3
)—; R
3
and R
4
are individually selected from at least one member of the group consisting of alkyl radicals containing from 1 to 20 carbon atoms, cycloalkyl radicals and phenyl radicals; the repeating units of formula I constitute up to 75 percent by mole of the total repeating units in said polyester.
The weight average molecular weights of the present polyesters are typically up to 10,000. The polyesters are useful as plasticizers for rigid organic polymers, particularly for homopolymers and copolymers prepared from at least one halogen-containing olefin. These olefins contain at least one halogen atom and from 2 to 6 or more carbon atoms. Suitable monomers include but are not limited to vinyl chloride, vinylidene chloride, vinylidene fluoride, 1-chloropropene, 1-chloro-2-butene, and tetrafluoroethylene.
The present polyesters are particularly suitable as primary plasticizers for homopolymers and copolymers of vinyl chloride and vinylidene chloride. Polyvinyl chloride and copolymers of vinyl chloride with at least one ethylenically unsaturated compound, such as vinyl acetate, styrene, and maleic and fumaric acids and esters thereof, are preferred for use with the present plasticizers.
The present polyesters are copolymers of diethylene glycol, at least one additional diol and at least one dicarboxylic acid. In addition to being compatible with the polymers into which they are incorporated, preferred embodiments of the present polyesters and polymer compositions containing these polyesters exhibit unexpected desirable properties. The polyesters exhibit a lower viscosity relative to polyesters of similar molecular weight prepared using diols other than diethylene glycol. Polymer compositions containing the present polyesters exhibit a higher surface energy, a lower glass transition temperature, and greater low temperature flexibility relative to compositions containing prior art polyesters.
As discussed in detail in the following paragraphs, the maximum allowable concentration of repeating units derived from diethylene glycol in polyesters that are compatible with halogen-containing polymers such as polyvinyl chloride is inversely proportional to the molecular weight of the polyester. As used in the present specification, “compatible” implies that at a concentration of 50 parts by weight per 100 parts of polyvinyl chloride the polyester will not exude from a strip molded from this composition under the conditions described in ASTM test D-3291. In the examples forming part of this specification, the test procedure was modified by changing the sample size from 12.7×25.4 mm. to 25.4×76.2 mm.
The present inventors have also discovered that in addition to molecular weight the type of terminal unit present in the polyester will also affect the maximum concentration of units derived from diethylene glycol that can be present in a compatible polyester.
For the purposes of the present invention, the weight average mol
Lang Jiamin
Luxem Franz Josef
Stanhope Bruce E.
Streeter Bruce E.
Zimmermann Eric R.
Fitch Even Tabin & Flannery
Hu Henry
Velsicol Chemical Corporation
Wu David W.
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