Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
1999-05-07
2001-06-05
Pezzuto, Helen L. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S290000, C526S308000, C526S335000
Reexamination Certificate
active
06242550
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a polymeric resin which is the reaction product of the polymerization reaction between dimethyl-dicyclopentadiene and limonene. Use of the polymeric resins of the present invention in a rubber tire stock improves the traction and handling of the tire.
SUMMARY OF THE INVENTION
The present invention relates to a polymeric dimethyl-dicyclopentadiene/limonene resin. The polymeric resins of the present invention have softening points ranging from about 50° C. to about 220° C., and a molecular weight of from about 500 to about 42,000. The present invention also includes a blend of dimethyl-dicyclopentadiene/limonene resins and rubber stocks containing the dimethyl-dicyclopentadiene/limonene resin.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a polymeric resin comprising the reaction product of the polymerization reaction between dimethyl-dicyclopentadiene and limonene and having a softening point ranging from about 50° C. to about 220° C. and a molecular weight ranging from about 500 to about 42,000.
In addition, the present invention relates to a resin composition comprising a blend of two or more polymeric resins wherein each resin comprises the reaction product of the polymerization reaction between dimethyl-dicyclopentadiene and limonene. Alternatively, the blend can be formed in-situ; that is, the reaction temperature may be raised during the polymerization to increase the molecular weight distribution and broaden the softening point.
In addition, there is disclosed a pneumatic tire having a tread comprised of a rubber stock comprising (1) a rubber selected from the group consisting of natural rubber, rubber derived from a diene monomer or mixtures thereof, and (2) a polymeric resin composition which is the reaction product of the polymerization reaction between dimethyl-dicyclopentadiene and limonene; said resin having a softening point ranging from about 50 to about 220° C. and a molecular weight ranging from about 500 to about 42,000.
There is also disclosed a rubber stock comprising (1) a rubber selected from the group consisting of natural rubber, rubber derived from a diene monomer or mixtures thereof, and (2) a polymeric resin composition which is the reaction product of the polymerization reaction between dimethyl-dicyclopentadiene and limonene; said resin having a softening point ranging from about 50 to about 220° C. and a molecular weight ranging from about 500 to about 42,000.
The terms “polymeric compound” and “polymer” when used to describe the resins of the present invention are intended to only include those molecules which contain a monomeric unit derived from dimethyl-dicyclopentadiene and limonene and where at least one of the monomeric units derived from the dimethyl-dicyclopentadiene or limonene is repeated. Therefore, the compounds formed by the reaction of a single dimethyl-dicyclopentadiene molecule and a single limonene are not polymeric as the term is used herein. The term monomeric unit means a structure that occurs in a polymeric compound and which differs from the structure of dimethyl-dicyclopentadiene or limonene due to changes resulting from molecular reorientation during the linking to the adjacent structure. These changes may include addition to a double bond or the addition or removal of a hydrogen atom from the dimethyl-dicyclopentadiene or limonene.
The weight ratio of the dimethyl-dicyclopentadiene to limonene in the polymerization reaction may vary, depending on the desired properties of the final polymeric product. For example, the weight ratio of the dimethyl-dicyclopentadiene to limonene as starting material may range from about 1:10 to about 10:1. The preferred weight ratio of dimethyl-dicyclopentadiene to limonene may range from about 5:1 to 1:5 as starting material. The most preferred ratio ranges from about 2:1 to 1:2. As to the final product, the weight ratio of polymeric units derived from the dimethyl-dicyclopentadiene to limonene may range from about 8:1 to 1:8. The preferred weight ratio of dimethyl-dicyclopentadiene to limonene in the final product ranges from about 1:3 to 3:1 with a range of from about 2.1:1 to 1:2.1, being particularly preferred.
The polymeric resinous material for use in the present invention comprises from 5 to 95 weight percent of units derived from dimethyl-dicyclopentadiene and from 95 to 5 weight percent of units derived from limonene. Preferably, the resin comprises from 33 to 67 weight percent of units derived from dimethyl-dicyclopentadiene and from 67 to 33 weight percent of units derived from limonene.
The polymeric resins may optionally be modified by the addition of up to 25 weight percent of units derived from hydrocarbons selected from C
9
and C
10
olefins and mixtures thereof. Therefore, at a minimum, no less than 75 weight percent of the units are derived from dimethyl-dicyclopentadiene and limonene. Preferably, from 5 to 10 weight percent of the units of the polymeric resin is derived from the above hydrocarbons.
The polymerization reaction between the dimethyl-dicyclopentadiene and the limonene may be a thermal (no catalyst) polymerization, or catalyzed, i.e., conducted in the presence of an acid catalyst. Examples of acid catalysts that may be used include Bronsted acid and Lewis acid-type catalysts. Such known acid catalysts include H
2
SO
4
, HCl, H
3
PO
4
; metal halides such as BF
3
, BCl
3
, AlCl
3
, AlBr
3
, SnCl
4
, ZnCl
2
, SbCl
3
and their etherates. The choice of a particular catalyst is dependent upon factors including the melting or boiling points of the reactants, desired rate of reaction, solvent, and pressure and temperature limitation of the production equipment, etc. When higher yields are desired, the metal halides or their etherates may be utilized. The preferred acid catalysts are BF
3
and AlCl
3
. The most preferred catalyst is AlCl
3
.
In the catalyzed polymerization process, the amount of catalyst may range from about 0.1 to about 20 weight percent of catalyst based on the total weight of reactants to be polymerized. Preferably, a range of from about 3 to about 5 weight percent of catalyst is preferred. The optimum concentration of catalyst depends on the nature of the solvent, if any, which effects the solubility of the catalyst as well as on the stirring efficiency inside the polymerization reactor.
The polymerization reaction may be carried out neat (without solvent) at or above the melting points of the reactants, or can be carried out in the presence of a solvent. The solvent may be an aliphatic C
6
-C
12
hydrocarbon, an aromatic or haloaromatic (C
6
-C
9
) hydrocarbon, or a C
6
-C
9
aliphatic halohydrocarbon. Examples of suitable solvents include hexane, heptane, cyclohexane, benzene, toluene, xylene, and chlorobenzene. The preferred solvents are heptane and cyclohexane.
The polymerization reaction may be conducted under a variety of operating conditions. The reaction pressure may vary and range from about one atmosphere to about 100 atmospheres with a pressure of from about two atmospheres to about ten atmospheres being preferred. The reaction temperature may range from about 0 to 100° C. with a preferred range being from about 25 to 50° C.
Depending on the reactivity of the reactants, amount of catalyst, reaction pressure and reaction temperature, the reaction time may vary. Generally speaking, the reaction time varies from about 1 to about 8 hours.
The molecular weight distribution of the polymeric resin of the present invention may range from about 500 to about 42,000. In a particularly preferred embodiment of the present invention, the resin composition may have a molecular weight distribution of from 500 to 29,500. The resin may comprise a blend of two or more individual polymeric resins each one of which is the reaction product of a polymerization reaction between dimethyl-dicyclopentadiene and limonene. Each individual polymeric resin preferably differs from the other by having a different molecular weight range. Generally speaking, all of the polymeric resins will e
Blok Edward John
Kralevich, Jr. Mark Leslie
Ruscak Joseph Miles
Sandstrom Paul Harry
Wideman Lawson Gibson
Hendricks Bruce J.
Pezzuto Helen L.
The Goodyear Tire & Rubber Company
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