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
1999-08-19
2001-03-13
Wyrozebski, Katarazyna (Department: 1714)
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...
C524S493000, C524S495000, C152S450000, C152S565000
Reexamination Certificate
active
06201059
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a polymeric resin which is the reaction product of the polymerization reaction between dicyclopentadiene and beta-pinene. Use of the polymeric resins of the present invention in a rubber tread stock improves the traction and handling of the tire.
SUMMARY OF THE INVENTION
The present invention relates to rubber compositions containing a polymeric dicyclopentadiene/beta-pinene resin. The polymeric resins of the present invention have a softening point ranging from about 100° C. to about 170° C., and a molecular weight distribution ranging from about 550 to about 55,000.
DETAILED DESCRIPTION OF THE INVENTION
There is 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 contains from 35 to 65 percent by weight of polymeric units derived from dicyclopentadiene and from 65 to 35 percent by weight of polymeric units derived from beta-pinene.
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 consisting essentially of the reaction product of the polymerization reaction between dicyclopentadiene and beta-pinene; 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 dicyclopentadiene and/or beta-pinene and where at least one of the monomeric units derived from the dicyclopentadiene or beta-pinene is repeated. Therefore, the compounds formed by the reaction of a single dicyclopentadiene molecule and a single beta-pinene 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 dicyclopentadiene or beta-pinene 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 dicyclopentadiene or beta-pinene.
The resin for use in the present invention contains from 35 to 65 percent by weight of polymeric units derived from dicyclopentadiene and from 65 to 35 percent by weight of polymeric units derived from beta-pinene. Preferably, from 45 to 55 percent by weight of the polymeric units are derived from dicyclopentadiene and from 45 to 55 percent by weight of the polymeric units are derived from beta-pinene.
As can be appreciated by one skilled in the art, commercially available hydrocarbon streams are rarely pure, but rather contain many isomers or derivatives. Therefore, it is contemplated herein that from 0 to 20 weight percent of the polymeric resin may be derived from a monomer other than dicyclopentadiene or beta-pinene. Preferably, from 0 to 10 weight percent of the polymeric resin may be derived from a monomer other than dicyclopentadiene or beta-pinene. Representative examples of such monomers include alpha-pinene, methyldicyclopentadiene and the like.
The molar ratio of the dicyclopentadiene to beta-pinene in the polymerization reaction may vary, depending on the desired properties of the final polymeric product. For example, the molar ratio of the dicyclopentadiene to beta-pinene as starting material may range from about 1:2 to about 2:1. The preferred molar ratio of dicyclopentadiene to beta-pinene may range from about 1:1 to 2:1 as starting material. The most preferred ratio ranges from about 1.1:1 to 1:1.1. As to the final product, the molar ratio of polymeric units derived from the dicyclopentadiene to beta-pinene may range from about 1:2 to 2:1 with a range of from about 1.1:1 to 1:1.1 being preferred.
The polymerization reaction between the dicyclopentadiene and the beta-pinene 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, H3PO
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 affects the solubility of the catalyst as well as on the stirring efficiency inside the polymerization reactor. High catalyst concentration reduces the resin molecular weight distribution and, therefore, limits the amount of feed additive required for controlling the resin molecular weight.
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 hexane 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 30 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 550 to about 55,000 as determined by small mollecular SPC. Preferably, the molecular weight distribution of the polymeric resin ranges from about 550 to about 52,500.
The polymeric resin composition has a softening point ranging from about 100 to about 170° C. For the purposes of the present invention, the term “softening point” is used to describe the temperature range from when wetting occurs in a capillary melting point tube to where the resin is completely liquid. Representative of suitable equipment to determine the relative softening point is a Thomas-Hoover Melting Point apparatus equipped with a silicone oil bath. In accordance with the preferred embodiment, the polymeric resin composition has a softening point ranging from about 130 to about 160° C.
Rubber stocks containing natural rubber or rubbers derived from a diene monomer may be modified with the resin compositions of the present invention. Examples of rubbers derived from a diene monomer include substituted and unsubstituted, saturated and unsaturated, synthetic polymers. The natural polymers include natural rubber in its various forms, e.g., pale crepe and smoked sheet, and balata and gutta percha. The synthetic polymers include those prepared from a single monomer (homopolymer) or a mixture of two or more copolymerizable monomers (copolymer) w
Blok Edward John
Kralevich, Jr. Mark Leslie
Sandstrom Paul Harry
Wideman Lawson Gibson
Hendricks Bruce J
The Goodyear Tire & Rubber Company
Wyrozebski Katarazyna
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