Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2001-06-20
2003-03-04
Sellers, Robert E.L. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S404000, C525S450000
Reexamination Certificate
active
06528586
ABSTRACT:
FIELD OF THE INVENTION
Disclosed are compositions of ethylene and (meth)acrylic acid and ester elastomeric copolymers or of (meth)acrylic ester elastomeric copolymers with polylactones and certain polyethers. These compositions have improved massing resistance in the uncured state and/or improved low temperature properties in the cured or uncured state. The polylactones or polyethers are preferably at least partially grafted to the elastomeric copolymers.
TECHNICAL BACKGROUND
Copolymers of ethylene and (meth)acrylic monomers, such as alkyl acrylates or methacrylates and acrylic or methacrylic acids, are well known items of commerce. They may broadly be divided into two categories, thermoplastics and elastomers. Most often the former contain relatively high amounts of ethylene, giving them crystallinity derived from ethylene sequences in the polymer. The latter tend to have relatively higher amounts of the (meth)acrylic monomers to break up the ethylene crystallinity, which often results in an elastomeric polymer. As is well known, thermoplastics and elastomers often have differing uses, and differing problems associated with them.
For example, because of their crystallinity and/or glassy natures, thermoplastics may be readily formed into pellets which hold their shape. However, uncured (unvulcanized) elastomers often have the problem of slowly flowing and agglomerating into one (often large) mass, so pellets of elastomers, an often desired product form, may be difficult to preserve in a package. One way of preserving elastomers as pellets is to coat the pellet surfaces with a so-called parting agent. With some elastomers which do not flow readily this may work, but for others an excessive amount of parting agent may be needed, or the parting agent will not prevent massing when used in almost any amount.
In most instances it is desirable that the elastomer stay flexible over as wide a temperature range as possible, particularly lower temperatures, where eventually elastomers become stiff and sometimes brittle. This is not a problem with thermoplastics which are supposed to be stiff. Thus methods for preventing massing and/or improving the low temperature properties of elastomers are commercially valuable.
Various thermoplastics made from ethylene and (meth)acrylic monomers have been reacted (grafted) and/or blended with poly(ethylene glycols), poly(propylene glycols) or polyesters, see for instance British Patent 936,732, U.S. Pat. Nos. 5,106,909, and 5,321,088, and World Patent Application 91/02767. None of these references specifically refer to the use of elastomeric ethylene co-polymers.
U.S. Pat. No. 3,637,544 discloses the mixing of various elastomers containing “ethylenic unsaturation” with polylactones such as polycaprolactones. No mention is made of elastomeric ethylene/(meth)acrylic copolymers.
SUMMARY OF THE INVENTION
This invention concerns a composition, comprising:
(a) an elastomeric first polymer consisting essentially of about 10 to about 80 mole percent of ethylene, about 10 or more mole percent of
and up to about 20 mole percent, total, of one or more other polymerizable olefins; and
(b) one or more second polymers chosen from the group consisting of poly(ethylene ethers), poly(1,2-propylene ethers) and polylactones;
wherein:
each R
1
is independently methyl or hydrogen; and
each R
2
is independently hydrogen, hydrocarbyl or substituted hydrocarbyl;
and provided that when said second polymer is a polylactone it is present as a separate polymer from said first polymer, and/or is grafted to said first polymer, and when said second polymer is said polyethylene ether) or said polypropylene ether) at least some of said second polymer is grafted to said first polymer.
Further disclosed is a second composition which is an elastomeric first polymer consisting essentially of about 60 or more mole percent of:
and up to about 40 mole percent of one or more comonomers selected from the group consisting of aromatic hydrocarbon olefins, acrylonitrile, olefinic monomers containing chlorine, epoxy, or carboxylic acid groups, maleic anhydride, monoalkyl and monoarylalkyl esters of maleic acid, monoalkyl and monoarylalkyl esters of fumaric acid, itaconic anhydride, monoalkyl and monoarylalkyl esters of itaconic acid, and cyanoalkyl acrylates wherein alkyl can contain 2-8 carbon atoms; and
(b) one or more second polymers chosen from the group consisting of poly(ethylene ethers), poly(1,2-propylene ethers) and polylactones;
wherein:
R
1
is methyl or hydrogen; and
R
2
is hydrocarbyl and/or substituted hydrocarbyl;
and provided that when said second polymer is a polylactone it is present as a separate polymer from said first polymer, and/or is grafted to said first polymer, and when said second polymer is said poly(ethylene ether) or said poly(propylene ether) at least some of said second polymer is grafted to said first polymer.
In this second composition it is preferred that R
2
is independently an alkyl containing 1-8 carbon atoms, optionally substituted by one or more ether oxygens. It is also preferred that R
1
is hydrogen and each R
2
is independently selected from the group consisting of ethyl, butyl, methoxyethyl, ethoxyethyl, and mixtures thereof, with a proviso that at least 50 mol. % of the R
2
groups be ethyl, butyl or a combination thereof. A preferred comonomer is acrylonitrile.
DETAILS OF THE INVENTION
Herein certain terms are used, and they are defined below.
By hydrocarbyl is meant a univalent radical containing only carbon and hydrogen. Unless otherwise specified it is preferred that it contain 1 to 30 carbon atoms.
By substituted hydrocarbyl is meant hydrocarbyl containing one or more substituents (functional groups) which do not interfere with (as appropriate) amidation, transesterification and crosslinking. Useful substituents include oxo (keto), halo, ether [which sometimes could be considered (substituted) hydrocarbyloxy groups] and thioether. Unless otherwise specified it is preferred that it contain 1 to 30 carbon atoms.
By a polymerizable olefin is meant an olefin which may copolymerize with ethylene and (I) under the polymerization conditions used to form the polymer.
By olefinic double bond is meant a carbon-carbon double bond which is not part of an aromatic ring.
By an (meth)acrylic compound is meant a compound of formula (I).
By a dipolymer is meant a copolymer containing repeat units derived from two monomers.
By a polyether is meant an organic group which contains two or more ether linkages.
By grafting is meant forming an attachment between a first polymer and a second polymer. It is preferred that the attachment contains esters, amide, imide or carbon-carbon bonds.
By elastomeric or an elastomer is meant that the heat of fusion of any polymer crystallites present with a melting point (Tm) of 50° C. or more is less than 5 J/g, more preferably less than about 2 J/g, and preferably no polymeric crystallites are present at 25° C. (by ASTM D3451), and that the glass transition temperature (Tg) of the polymer is less than about 50° C., more preferably less than about 20° C., and especially preferably less than about 0° C. The Tm and heat of fusion of the polymer are determined by ASTM method D3451 at a heating rate of 10° C./min and the Tm is taken as the peak of the melting endotherm, while the Tg of the polymer is determined using ASTM Method E1356 at a heating rate of 10° C./min, taking the midpoint temperature as the Tg. Both of these are determined on a second heating of the polymer.
Preferably the first polymer used in the present invention is a copolymer of ethylene and (I) [more than one species of (I) may be present], or of ethylene and (I) and the monoethyl ester of maleic or fumaric acids or maleic anhydride. In (I) it is preferred that R
1
is hydrogen and/or R
2
is hydrocarbyl, more preferably alkyl containing 1 to 6 carbon atoms, and especially preferably methyl [when R
1
is hydrogen and R
2
is methyl, (I) is methyl acrylate]. A particularly preferred first polymer is ethylene/methyl acrylat
Cohen Gordon Mark
Dawson Robert Louis
Harrell Jerald Rice
Lee Sampson Chun-Fai
Mitchell David John
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