Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2001-03-23
2003-07-29
Sanders, Krellion A. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C252S407000, C549S364000
Reexamination Certificate
active
06599964
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to plastic additives which are useful as nucleating agents and which are especially useful for improving the optical properties of polymeric materials. More particularly, this invention relates to certain symmetric DBS compounds comprising specific pendant groups, such as C
3
-C
6
alkyl, C
1
-C
6
alkoxy, nitro, as well as phenyl and methylenedioxy(as the combination of two available sites on the pertinent ring system), and furthermore the benzylidene rings may be indan or tetralin. Because of the required symmetrical configuration, the pendant groups on each ring system of the dibenzylidene sorbitol compound must be located at the same positions. Such compounds may be added to or incorporated within polymer compositions which may then be utilized within, as merely examples, food or cosmetic containers and packaging.
BACKGROUND OF THE PRIOR ART
All U.S. Patents cited below are herein entirely incorporated by reference.
Numerous attempts have been made to improve the clarity and physical properties of polyolefins through the incorporation of certain kinds of additives. Certain applications require good clarity or transparency characteristics. These include certain types of plastic plates, sheets, films, containers, and syringes that need to exhibit clarity primarily to facilitate identification of articles, etc., stored, wrapped, and/or covered therewith. Such commercially available plastic additives fall into two categories termed “melt sensitive” and “melt insensitive”. Melt sensitive additives possess melting points below or near the normal processing temperatures of polyolefin-based resins and include dibenzylidene sorbitol (DBS) systems. Melt insensitive additives do not melt at normal processing temperatures and include sodium benzoate and salts of organic phosphates as examples.
U.S. Pat. No 4,016,118 to Hamada, et al. teaches that a polyolefin plastic composition containing 0.1% to 0.7% dibenzylidene sorbitol (DBS) as an additive will show improved transparency and reduced molding shrinkage over compositions containing a substituted benzoic acid salt. Additional advancements in sorbitol-based clarification technology have been driven by the need for improved transparency, reduction of plate-out during processing, and improved organoleptic properties (e.g., odor, taste, etc.). In order to overcome these deficiencies, many derivatives of DBS in which the aromatic rings are substituted with various groups have been proposed.
Mahaffey, in U.S. Pat. No. 4,371,645 discloses a series of dibenzylidene sorbitols having the general formula:
wherein R, R
1
, R
2
, R
3
, and R
4
, are selected from hydrogen, lower alkyl, hydroxy, methoxy, mono- and di-alkylamino, amino, nitro, and halogen, with the proviso that at least one of R
1
, R
2
, R
3
, and R
4
is chlorine or bromine. Effective concentrations of the disclosed substituted DBS derivatives range from 0.01 to about 2 percent of the total composition by weight. Further improvements in transparency characteristics are disclosed by Titus, et al. in U.S. Pat. No. 4,808,650. In this patent mono and disubstituted DBS derivatives having the formula:
in which R may be hydrogen or fluorine provide improved clarity applications in polyolefins. Rekers, in U.S. Pat. No. 5,049,605 discloses a series of dibenzylidene sorbitols having the general formula:
in which R
1
and R
2
are independently selected from lower alkyl groups containing 1-4 carbons which together form a carbocyclic ring containing up to 5 carbon atoms. Also disclosed are polyolefin plastics containing the above group of dibenzylidene sorbitols. Videau, in U.S. Pat. No. 5,696,186 discloses substituted DBS derivatives with an alkyl group (methyl, ethyl, or the like) or halogen (fluorine, chlorine, or the like) on the benzene rings for use as nucleation/clarification agents in polyolefins.
Dibenzylidene sorbitol (DBS) is a well known gelling agent for a variety solvent systems as disclosed in U.S. Pat. No. 4,154,816, Roehl et al.; U.S. Pat. No. 4,816,261, Luebbe et al.; and U.S. Pat. No. 4,743,444 to McCall. U.S. Pat. No. 5,609,855 to Oh et al. and PCT Patent Application WO/92/19221 to Juneja et al.; disclose that di(meta-fluorobenzylidene) sorbitol and di(meta-chlorobenzylidene) sorbitol are extremely useful as gelling agents in the preparation of antiperspirant gel sticks. These two respective DBS systems form effective hard gels and show improved gel stability in the acidic environment of antiperspirant formulations.
DETAILED DESCRIPTION OF THE INVENTION
According to the present invention, a polyolefin plastic composition having improved transparency is provided which comprises a polymer selected from aliphatic polyolefins and copolymers containing at least one aliphatic olefin and one or more ethylenically unsaturated comonomers and at least one mono-, di-, or tri-acetal which is the reaction product of at least one mole of alditol (such as sorbitol, xylitol, ribitol, and the like) and at least one mole of a benzaldehyde selected from the compounds conforming with Formula (I)
wherein R
1
, R
2
, R
3
, R
4
, and R
5
are independently selected from the group consisting of hydrogen, alkyl groups containing 3-6 carbon atoms, alkoxy groups containing 1-6 carbon atoms, and phenyl, or any two adjacent groups may be combined to form a cyclic group, wherein said cyclic group is selected from the group consisting of methylenedioxy, cyclopentyl, and cyclohexyl; with the proviso that at least one group of R
1
, R
2
, R
3
, R
4
, and R
5
is a group other than hydrogen. Preferably, such a reaction product is a di-acetal (and thus the result of a 1:2 molar ratio reaction between the alditol and benzaldehyde), and particularly where the alditol is sorbitol, said di-acetal reaction product conforming to the structure of Formula (II):
wherein p is 0, 1, or 2, R
1
, R
2
, R
3
, R
4
, and R
5
are independently selected from the group consisting of hydrogen, alkyl groups containing 3-6 carbon atoms, alkoxy groups containing 1-6 carbon atoms, or any two adjacent groups may be combined to form methylenedioxy; with the proviso that at least one group of R
1
, R
2
, R
3
, R
4
, and R
5
is a group other than hydrogen.
It should be appreciated with regard to the structural formula set forth above that while only the 1,3:2,4 isomer is represented, this structure is provided for convenience only and the invention is not limited to only isomers of the 1,3:2,4 type, but may include any and all other isomers as well so long as the compound contains two aldehyde substitutents on the alditol moiety.
Throughout this specification, the term “symmetrical” as it pertains to di- or tri-acetals of alditols is intended to mean wherein such alditol acetals that possess all acetal linkages (such as 1,3- and 2,4- for di-acetals) derived from the same benzaldehyde.
The diacetals, triacetals, and monoacetals of the present invention are condensation products of alditol, such as sorbitol or xylitol, and specific substituted benzaldehydes (including arylaldehydes). In accordance with this invention, specific examples of suitable substituted benzaldehydes include 4-t-butylbenzaldehyde, 4-isopropylbenzaldehyde, 3,4-methylene-dioxybenzaldehyde, 3,4-dimethoxybenzaldehyde, 3,4-diethoxybenzaldehyde, and the like, to provide the required symmetrical compounds in reaction with an alditol (such as sorbitol, xylitol, ribitol, and the like). Other suitable substituted benzaldehydes for this inventive compounds include, without limitation, 2,4-diisopropylbenzaldehyde, 2,4-di-t-butylbenzaldehyde, 2,4-dimethoxybenzaldehyde, 2,4,5-trimethoxybenzaldehyde, 2,4-diethoxybenzaldehyde, 4-n-pentylbenzaldehyde, 3-methyl-4-methoxybenzaldehyde, 4-methoxy-2,3-dimethylbenzaldehyde, 3-methoxy-2,4-dimethylbenzaldehyde, 2,4-dimethoxy-3-methylbenzaldehyde, 4-ethoxy-3,5-dimethylbenzaldehyde, and 3-isopropyl-4-methoxybenzaldehyde, and the like. Preferred di-acetals of the present invention include 1,3:2,4-bis(4-t-butylbenzylidene) sorbitol and 1,3:2,4-bis(3,4-methylenedioxybenzylidene) sorbitol.
Jones Jeffery R.
Mehl Nathan A.
Milliken & Company
Moyer Terry T.
Parks William S.
Sanders Krellion A.
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