Blends of hardened extract with copolymers of olefin/alkyl acrylate

This invention relates to a blend of an olefin/alkyl acrylate copolymer and hardened extract which has a saturated hydrocarbon content of not more than 10% by weight and articles made therefrom, e.g. linings for reservoirs and for water proofing roofs. The new products are easier to manufacture since they resist gelation, do not suffer from problems of shrinkage and are appreciably cheaper.

The present invention relates to blends of hardened extract with copolymers 
of an olefin and an alkyl acrylate. 
Elastomer blends containing hardened extract and chlorosulphonated 
polyethylene are known for use as waterproof membranes, eg for tank 
linings as shown by "Encyclopedia of Chemical Technology" edited by 
Kirk-Othmer 2nd Edition, Volume 7, page 695. Chlorosulphonated 
polyethylene elastomers have a number of disadvantages however, Thus for 
many purposes they have too low a modulus and tear strength. 
It would be desirable to find a method of improving the physical properties 
of chlorosulphonated polyethylene elastomers and also a way of making a 
cheaper product based on modified polyethylene elastomers. When attempts 
are made to add bitumen to chlorosulphonted polyethylene to give a cheaper 
product, the resulting material has an exceedingly low tensile strength 
and modulus. 
Although useful compositions have been obtained by using, instead of 
bitumen, a product known as hardened extract or aromatic extract resin, 
such compositions cause gelation of the copolymer if high processing 
temperatures are used. 
It has been found that these problems can be mitigated by replacing the 
chlorosulphonated polyethylene ith an olefin/alkyl acrylate copolymer. 
According to the present invention there is provided a blend of an 
olefin/alkyl acrylate copolymer and hardened extract (as hereinafter 
defined), said hardened extract having a saturated hydrocarbon content of 
not more than 10% by weight. 
According to yet another aspect of the present invention there is provided 
an article comprising an olefin/alkyl acrylate copolymer and hardened 
extract having a saturated hydrocarbon content of not more than 10% wt/wt. 
THE OLEFIN/ALKYL ACRYLATE COPOLYMER 
The olefin/alkyl acrylate copolymers used in the present invention are 
suitably elastomers. Such copolymers and methods of production thereof are 
described, for instance, in U.S. Pat. Nos. 2,953,541 and 2,953,551. The 
olefins in the copolymer is preferably ethylene or propylene and the alkyl 
acrylate is preferably methyl acrylate, ethyl acrylate, propyl acrylate, 
pentyl acrylate, 2-ethyl hexyl acrylate or decyl acrylate. Copolymers of 
ethylene and ethyl acrylate are most preferred. In this case the ethylene 
polymer is preferably a low density polyethylene. The olefin/alkyl 
acrylate copolymer in general, and the ethylene/ethyl acrylate copolymer 
in particular, suitably contains between 3 and 18% by weight, preferably 
between 8 and 18% by weight, of the alkyl acrylate. 
THE HARDENED EXTRACT 
Throughout this specification `hardened extract` means a material obtained 
by blowing a gas containing free oxygen into a petroleum extract at 
elevated temperatures, the petroleum extract having been obtained by the 
solvent extraction of a product of petroleum refining which is a 
distillate petroleum fraction or a de-asphalted petroleum residue, which 
product boils above 350.degree. C. at atmospheric pressure and which 
contains a major proportion of aromatic hydrocarbons. 
The product of petroleum refining subjected to solvent extraction may be 
for example a vacuum distillate obtained by vacuum distillation of a 
residue from an atmospheric pressure distillation. Alternatively, the 
product of the petroleum refining may be obtained from vacuum residue (the 
residue of the vacuum distillation referred to above) after asphaltenes 
have been removed by precipitation with liquid propane. A product 
containing a major proportion of aromatic hydrocarbons may be derived by 
solvent extraction of mixtures of distillates and residues. 
A by-product of petroleum refining is vacuum distillate which is in the 
lubricating oil boiling range of 350.degree. C. to 600.degree. C. Such 
vacuum distillates are well known to those skilled in the art. 
The elevated temperature at which the gas containing free oxygen eg air is 
blown into the petroleum extract may for example be 200.degree. to 
350.degree. C. 
Examples of solvents which may be used to extract the petroleum distillate 
fraction are furfural, phenol and N-methyl pyrrolidone. The product 
subjected to extraction is substantially free from asphaltenes, and this 
extraction process must be distinguished from a process in which liquid 
propane is used to obtain from residues a product rich in asphaltenes. The 
latter process is sometimes described as a `solvent` process. 
Examples of such petroleum extracts are materials sold under the 
designation `Enerflex`(Regd. Trade Mark) Process Oils by BP Oil 
International Limited, London. It is desirable that the hardened extract 
is prepared from a petroleum extract having a content of `saturates` and 
`aromatics` as determined by molecular-type analysis (clay-gel) ASTM 
D2007, of less than 15% by weight preferably less than 10% by weight for 
saturates, and suitably more than 75% by weight, preferably more than 80% 
by weight for aromatics. 
The `hardened extract` resulting from the air blowing referred to above is 
a solid material at room temperature. In order to obtain a hardened 
extract having the desired low content of saturated hydrocarbons it may be 
necessary to select a petroleum extract in which the saturated hydrocarbon 
content is low. The choice of a suitable petroleum extract can readily be 
made by the man skilled in the art on the basis of simple tests. The 
blowing with air may be carried out in the presence of a catalyst eg a 
metal halide Friedel-Crafts catalyst such as ferric chloride, or without a 
catalyst. 
The hardened extracts used in the present invention are to be distinguished 
from bitumens by the fact that they are made by either distillation or by 
de-asphalting a residue, followed by a solvent extraction, to produce a 
product which is substantially free of asphaltenes, the asphaltenes only 
being introduced by blowing with a gas containing free oxygen. When crude 
oil is distilled to remove materials boiling up to the end of the gas oil 
range, the resulting residue, known as atmospheric residue, can be 
subjected to vacuum distillation to recover waxy distillates. The residue 
from this vacuum distillation is known as vacuum residue. The bitumen may 
be obtained directly from this residue or the residue may be air blown to 
produce a low penetration bitumen. Alternatively, the residue (either 
atmospheric or vacuum) may be treated with for example liquid propane to 
precipitate a bitumen layer. In all these cases the asphaltenes in the 
bitumen comes directly from the residue, and there is no intermediate 
material formed which is substantially free of asphaltenes. 
The composition of hardened extracts and bitumens may be determined on the 
basis of their content of certain classes of material, namely 
`asphaltenes`, `toluene insolubles`, `saturates`, `cyclics` and `resins`. 
In this method asphaltenes are defined as that fraction which is 
precipitated by a large excess of n-heptane but which is soluble in 
toluene. Toluene insolubles are that fraction which is insoluble in 
toluene. Saturates are defined as that fraction which is eluted by 
n-heptane from an alumina/silica gel column, cyclics as that fraction 
which is eluted by toluene, and resins as that fraction which is eluted by 
a 50/50 toluene/absolute ethanol mixture. 
Typical data on hardened extracts and bitumens are given in Table 1 where 
"HE" means `hardened extract` and the number following "HE" is the 
softening point. 
It will be seen that the hardened extracts have lower saturated hydrocarbon 
contents and much higher asphaltenes and toluene insolubles contents than 
either straight run or blown bitumens of equivalent softening point. The 
hardened extracts used suitably have asphaltenes plus toluene insolubles 
contents of at least 20% by weight. Preferably the content of asphaltenes 
alone is at least 20% by weight. 
Hardened extracts having a range of softening points are readily available. 
Thus hardened extracts having softening points ranging from 50.degree. C. 
to 200.degree. C. may be used. It is preferred to use hardened extracts 
having a softening point in the range 85.degree.-170.degree. C. The 
softening point of hardened extract is measured by the ring and ball test 
used to determine the softening point of bitumens. This is described in 
Chapter 13 page 12 l of "Petroleum Products Handbook" edited by Guthrie 
and published in 1960 by McGraw Hill. 
TABLE 1 
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BROAD CHEMICAL COMPOSITION OF BLOWN 
BITUMEN AND HARDENED EXTRACTS 
85/25 
115/15 Blown 
Straight 
Kuwait Run 
Bitumen Bitumen HE 140 
______________________________________ 
Softening Point 
115 85 140 
Ring and Ball .degree.C. 
Penetration at 
15 25 less 
25.degree. C. mm/10 than 1 
BCC Analysis % 
Saturates 18.1 10.0 9.6 
Cyclics 33.2 55.3 28.0 
Asphaltenes 32.5 7.1 50.4 
Resins 14.9 26.1 12.2 
Toluene Insolubles 
2.1 1.5 40.5 
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CHLORINATED POLYETHYLENES 
The composition of the present invention may contain chlorinated 
polyethylenes in addition to the olefin/alkyl acrylate copolymer and the 
hardened extract. 
Chlorinated polyethylenes with chlorine contents of from 20 to 48% by 
weight may be used. It is preferred to use chlorinated polyethylenes based 
on high density polyethylene having chlorine contents of from 25 to 40% by 
weight chlorine. Particularly preferred are chlorinated polyethylenes CPE 
2552 and CPE 3614 which contain 25% and 36% by weight chlorine 
respectively and which are manufactured by Dow Chemical Company. 
OTHER OPTIONAL ADDITIONAL INGREDIENTS 
The compositions of the present invention may also contain particulate 
fillers that are commonly used in reinforcing rubber, eg calcium 
carbonate, carbon black, titanium dioxide, clay, talc, etc. The use of 
these fillers can improve the tear strength of the blend. Fibrous fillers 
and coated fibrous fillers such as asbestos, cotton, polyester fibres, 
rayon fibres etc may also be used. 
The compositions of the present invention may also contain various 
additives, eg to plasticise, to lubricate, to stabilise, to enhance fire 
resistance and to prevent oxidation, providing these are compatible with 
the composition, ie do not readily separate from the composition after 
being mixed with it. Compatibility is particularly significant in the 
context of plasticisers. Examples of such plasticisers are aromatic 
extracts (this being the material from which hardened extract is 
prepared), chlorinated paraffins, for example those having from 12 to 30 
carbon atoms in the molecule, and esters, for example di-2-ethylhexyl 
phthalate or alkyl epoxy stearates. Plasticisers for use in olefin/alkyl 
acrylate copolymers are well known to those skilled in the art. 
Compositions containing the above-mentioned optional additional ingredients 
may be used in either unvulcanised or vulcanised form. 
RELATIVE QUANTITIES OF INGREDIENTS 
The relative weights of olefin/alkyl acrylate copolymer and hardened 
extract used in the compositions of the present invention may vary over a 
wide range but are preferably 4:1 to 1:10, more preferably 2:1 to 1:5, for 
example 1:1. 
Where chlorinated polyethylene is present the weight of chlorinated 
polyethylene relative to olefin/alkyl acrylate copolymer is preferably in 
the range 1:9 to 4:1, more preferably 1:4 to 2:1, for example 1:1. 
The quantity of particulate filler, if present, is preferably in the range 
1 to 250, more preferably 10 to 150 parts per hundred parts of the 
olefin/alkyl acrylate copolymer (and chlorinated polyethylene, if 
present), all parts being by weight. 
The quantity of plasticiser, if present, is preferably in the range 1 to 
50, more preferably 5 to 25 parts by weight per hundred parts by weight of 
the olefin/alkyl acrylate copolymer (and chlorinated polyethylene if 
present). 
The quantity of fibrous filler, if present, is preferably in the range 1 to 
50, more preferably 2 to 25 parts by weight per hundred parts by weight of 
the olefin/alkyl acrylate copolymer (and chlorinated polyethylene if 
present). 
PREATION OF THE COMPOSITIONS 
The compositions of the present invention may be prepared by any convenient 
method. Thus any of the methods used in compounding rubbers may be used, 
eg the methods using a Banbury mixer,, or a 2-roll mill. 
USES OF COMPOSITIONS ACCORDING TO THE PRESENT INVENTION 
Compositions according to the present invention are particularly useful 
when formed into articles, especially into sheets for lining reservoirs or 
for waterproofing roofs. Such sheets may be, for example, formed by 
moulding or by calendering between heated rollers. The compositions of the 
present invention may be also used to produce bituminous mastic backed 
products, polyester felt backed products and laminates in which non-woven 
scrims may be used as reinforcements. Bitumen is compatible with the 
compositions of the present invention and causes no bleeding. 
The invention will now be illustrated by the following Examples in which 
all parts are parts by weight. 
The meaning of the various trade names and abbreviations used in these 
Examples is as follows: 
______________________________________ 
Terms Meaning 
______________________________________ 
Hypalon 45 
A chlorosulphonated polyethylene containing 
25% Cl and 1.0% of S produced by E. I. du 
Pont de Nemours. 
He 140 A Hardened Extract having a softening point 
of 140.degree. C. 
EEA 6178 An ethylene ethyl acrylate copolymer 
containing 10% ethyl acrylate and produced 
by BP Chemicals Limited. 
FEF Black A fast extrusion furnace carbon black 
produced by Cabot. 
CPE 3614 `A` 
A chlorinated polyethylene containing 36% 
chlorine produced by Dow. 
Mistron talc 
Pure magnesium silicate. 
Rigidex HDPE 
High Density Polyethylene produced by BP 
180/52 Chemicals Limited. 
Edenol B35 
An alkyl epoxy stearate plasticiser produced 
by Henkel et Cie. 
Amine Octadecylamine processing aid. 
______________________________________

EXAMPLES 1-6 
A composition was prepared by mixing all the ingredients (shown for the 
respective Examples in Table 2 below) in a 1-liter laboratory Banbury 
rubber mixer at 130.degree.-140.degree. C. for 10 minutes. The resulting 
mixture was then milled on a 6".times.12" two roll laboratory mill at 
130.degree. C. for 60 minutes to assess the effect of extensive 
processing. No gelation occurred during the milling as evidenced by the 
smooth appearance of the sheet on the mill. 
1 mm thick sheets from which samples of testing physical properties were 
cut, were prepared by moulding the composition taken from the mill for 5 
minutes a 130.degree. C. and then cooling the sheets in the mould. 
The ingredients used and the results obtained are shown in Tables 2 and 3. 
COMATIVE TEST (NOT ACCORDING TO THE INVENTION) 
A composition was prepared by mixing all the ingredients shown in Table 2 
in a 1-liter laboratory Banbury rubber mixer at 130.degree.-140` C. for 10 
minutes. The resulting mixture was then milled on a 6".times.12" two-roll 
laboratory mill at 130.degree. C. for 60 minutes. The mixture became rough 
in texture and very sticky on the mill. The mixture had gelled. 1 mm thick 
sheets from which samples for testing physical properties were cut, were 
prepared by moulding the composition taken from the mill for 5 minutes at 
130.degree. C. and then coding the sheets in the mould. 
The ingredients used and the results obtained are shown in Tables 2 and 3. 
TABLE 2 
__________________________________________________________________________ 
Ingredients (parts by weight) 
(Total charge fed to the Banbury mixer was 1.1 kg in each cases, the 
proportions by weight being as before) 
CPE HYON 
HDPE 
HE BLACK 
TALC EDENOL 
Example 
EEA 
3614A 
45 180/52 
140 
FEF MISTRON 
B35 AMINE 
__________________________________________________________________________ 
1 40 60 0 0 85 40 0 8 1 
2 50 50 0 0 85 40 0 8 1 
3 60 40 0 0 85 40 0 8 1 
4 40 50 0 10 85 40 10 8 1 
5 50 50 0 0 90 40 0 8 1 
6 50 50 0 0 85 40 10 8 1 
Comparative 
0 50 50 0 85 40 0 8 1 
Test 
__________________________________________________________________________ 
TABLE 3 
__________________________________________________________________________ 
Physical Properties 
Dimensional 
Brittle 
Tensile 
Elongation 
Modulus 
Test Shore 
stability 
Temp. strength 
at break 
at 300% 
Strength 
`A` 
Test DIN DIN BS 903 
BS 903 
BS 903 
BS 903 
BS 903 
Method 53377 53361 Part A2 
Part A2 
Part A2 
Part A3 
Part A26 
__________________________________________________________________________ 
Example No. 
1 1.5% -20.degree. C. 
7.4 670 4.2 38 69 
2 1.0% -25.degree. C. 
6.3 720 3.8 41 72 
3 0.5% -22.5.degree. C. 
6.4 620 4.5 41 74 
4 0 -- 6.0 600 4.7 40 78 
5 0.5% -22.5.degree. C. 
6.3 710 3.7 39 72 
6 0.5% -20.degree. C. 
5.8 670 4.0 42 71 
Comparative 
14% -25.degree. C. 
8.3 580 5.6 40 62 
Tests 
__________________________________________________________________________ 
From the above results, in particular by a comparison of the data in 
Example 2 with the Comparative Test, it can be seen that compositions 
containing ethylene/ethyl acrylate copolymer instead of a 
chlorosulphonated polymer were vastly superior showing no gelling and 
possessing the desired characteristics such as high tensile strength, high 
elongation at break, low modulus and high Shore `A` tests. Under the 
conditions used, the product from the Comparative Tests, in fact, gelled 
and vulcanised.