Note: Descriptions are shown in the official language in which they were submitted.
3L~16~
CIP NO. 2 of C-4748
Background oE the Invention
Field of the ~nvention
.
The present invention relates to an internally plasti-
cized copolymer of vinyl chloride, an alkyl acrylate and a bis
(hydrocarbyl)vinylphosphonate.
Description of the Prior Art
External plasticizers in vinyl chloride homo- and copoly-
mers are commonly employed today to form products having the re-
quired degree of flexibility for a given purpose. Such external
plasticization, however, it not entirely satisfactory since the
plasticizer tends to migrate to the surface and eventually is
lost either by ~olatilization or extraction. q'his loss gives rise
to such problems as surface stickiness, au-tomotive windshield fog-
ging and embrittlement of vinyl films containing the polymer
which are ~Ised in such applications as shower curtains, baby pants,
vinyl seat covers, and the like. Hence, various proposals for
"internal plasticization" of vinyl chloride polymers have been
made wherein the plasticizing action is supplied by one or more
comonomers for vinyl chloride which are polymerized with the
vinyl chloride to form the polymer.
The use of copolymers of a vinyl monomer and a polymer-
izable polyester, for example, an acrylate or a vinyl ester of
a polyester of an aliphatic hydroxycarboxylic acid, was proposed
in U.S. Patent No. 3,640,927 to C. S. Marvel et al. An in-ternal-
ly plasticized, two component vinyl chloride copolymer containing
from about 75% to about 95% vinyl chloride and about 25% to about
5% of an ester of an unsaturated mono- or polycarboxylic acid,
e.g., a C6-C~ 2 alkyl maleate, fumarate or acrylate, was proposed
-- 2 --
CIP NO. 2 of C-4748
in V.S. Pa-tent No. 3,54~,661 to A. 0th et al. ~ four component
polymer composition containing vinyl chloride, a dialkyl maleate
or fumarate, an alkyl ester of acrylic or methacrylic acid and a
monohydrogen, monoalkyl maleate or fumarate was proposed in U.S.
Patent No. 3,196,133 to R. A. Piloni et al. for use as a solvent-
based coating having both good adhesiveness and flexibility. In
selgian Patent 863,22S, by
R. E. Gallagher et al. an internally plasticized copolymer of
vinyl chloride, a C1-C10 alkyl acrylate and a C8-C22 dialkyl
maleate or fumarate is disclosed.
Two component copolymers of vinyl chloride and such acryl-
ates as 2-ethylhexyl acrylate, as seemingly suggested by certain
portions of the 0th et al. patent produce heterogeneous rasin com-
positions which do not show the desirable performance properties
of flexible vinyl films of the present invention.
A variety of two component vLnyl chloride/vinylphosphon-
ate copolymers are known which canno~: be classified as in-ternally
plasticized copolymers (U.S. Patents Nos. 3,691,127, 3,792,113
and 3,819,770) since copolymerizing just vinyl chloride and a
bis(hydrocarbyl)vinylphosphonate, e.g., bis(beta chloroethyl)
vinylphosphonate, leads to production of a resin which gives a
hard, relatively unflexible film requiring external plasticiza-
tion. It does not appear to have been hitherto appreciated that
a vinyl chloride/acrylate/vinylphosphonate copolymer, as de-
scribed and claimed herein,would have flexibility characteris-
tics as well as performance properties equivalent in many re-
spects to externally plasticized polyvinyl chloride without hav-
ing to add a substantial amount of external plasticizer. Unex-
pectedly, the bis(hydrocarbyl)vinylphosphonate monomer aids in
rendering the terpolymer less heterogeneous in appearance and
resulting properties than if only vinyl chloride and an alkyl
acrylate were used as comomers as suggested by certain prior art
-- 3 --
9~
CIP NO. 2 of C-~748
patents. The copolymer also has reduced smoke generation char-
acteristics.
Summary of the Present Invention
The copolymer of the present invention is an internally
plasticized vinyl chloride copolymer of from about 50% to about
~5%, by weight, vinyl chloride, from about 3~ to about 47%, by
weight, of a C6-C10 alkyl acrylate, e.g., 2-ethylhexyl acrylate,
and from about 3% to about 47~, by weight, of a bis(hydrocarbyl)
vinylphosphonate, e.g., bis(beta-chloroethyl)vinylphosphonate.
The copolymer is formed using conventional suspension, emulsion,
bulk and solution polymerization techniques and can be used in
those applications where externally plasticized polyvinyl chlor-
ide is used,e.g., as a vinyl film or sheeting material, in vinyl
wire and cable insulation, as vinyl flooring, and as bag and tub-
ing for blood transfusion equipment.
Description of the Preferred Embodiments
It has been unexpectedly found that a flexible vinyl film
prepared from an internally plasticized vinyl chloride polymer
without any external plasticization exhibits a Clash-Berg value
of about 0C. or below, preferably about -15 C. or below, and a
tensile strength at break of at least about 60 kg./cm. 2 or higher,
preferably about 85 kg./cm. 2 or greater. Such an internally plas-
ticized polymer can be formed with conventional emulsion, suspen-
sion, bulk and solution polymerization procedures by using a
basic three component monomer charge which contains certain amounts
of vinyl chloride, a C~-C10 alkyl acrylate,and a bis(hydrocarbyl)
vinylphosphonate, e.g., bis(beta-chloroethyl)vinylphosphonate.
The invention is, more particularly, an internally plasticized
-- 4 --
67~0
CIP N~. 2 of C-~748
copolymer which contains from about 50~ to about ~5%, by weight,
of vinyl chloride, from about 3% to about 47%r by weight, of a
C6-C1o alkyl acrylate, and from about 3% to about 47%, by weight,
of a bis(hydrocarbyl)vinylphosphonate copolymerized therein.
The terminology "bis(hydrocarbyl)vinylphosphonate" as used
in the present application is meant to encompass vinylphosphon-
ates having the formula:
X O
~ R'~
CH2-C-P~
~ OR~
wherein X is selected from the group consisting of hydrogen, halo-
gen, cyano, aryl, such as phenyl, Cl-Cl 8 alkyl and
o
OR'~
~ OR-
wherein R and R' are hydrocarbyl and substituted hydrocarbyl
groups con~isting essentially of hydrogen and carbon,and contain-
ing up to about 18 carbon atoms inclusive, with the proviso that
R and R' may be the same, different or conjoint, i.e., R and R'
may combin~ to form one single radical.
The use, in this disclosure, of the expression "hydro-
carbyl" and "substituted hydrocarbyl groups" in the definition
of the suitable bis(hydrocarbyl)vinylphosphonates given herein-
above refers to the radicals obtained upon the removal of a hydro-
- gen from a hydrocarbon or substituted hydrocarbon group which may
be either an aliphatic or aromatic group. These hydrocarbyl
groups may be substituted with any non-interferring groups, i.e.,
with any group which does not interfere with the polymerization
of the bis(hydrocarbyl~vinylphosphonate. Such substituent groups
include, for example, chloro, bromo, fluoro, nitro, hydroxy, sul-
fone, ethoxy, methoxy, nitrile, ether, ester and keto groups and
the like.
_ 5 _
11~6~
CIP NO. 2 of C-47~8
Illustra-tive of the aliphatic and aromatic groups as
represented by R and R' in the structure of the bis(hydrocarbyl)
vinylphosphonate given hereinabove are alkyl groups, such as
methyl, ethyl, propyl, butyl, pentyl, hexyl, nonyl, and the like;
alkenyl groups, such as pentenyl and hexenyl groups and all of
their respective isomers; cycloalkyl groups, such as cyclopropyl,
cyclobutyl, cyclopentyl, cyclohexyl and the like; cycloalkenyl
groups, such as cyclohexenyl and the like; typical aryl groups
include phenyl, benzyl, phenethyl, tolyl, naphthyl and the like.
Representative of the above-defined bis(hydrocarbyl)vinyl-
phosphonates are:
Bis(beta-chloroethyl)vinylphosphonate;
Bis(2-ethylhexyl)vinylphosphonate;
Bis(beta-chloropropyl)vinylphosphonate;
Bis(beta-chloroethyl) l-methy].vinylphosphonate;
Bis(beta-chloroethyl) l-cyanovinylphosphonate;
Bis(beta-chl.oroethyl)l-chlorovinylphosphonate;
Bis(beta-chloroethyl) l-phenylvinylphosphonate;
Dimethyl vinylphosphonate
Diethyl vinylphosphonate;
Bis(omega-chlorobutyl)vinylphosphonate;
Di-n-butyl vinylphosphonate;
Di-isobutyl vinylphosphonate;
Bis(2-chloroisopropyl) l-methylvinylphosphonate
Diphenyl vinylphosphonate; and
Bis(2,3-dibromopropyl)vinylphosphonate
From the above group of bis(hydrocarbyl)vinylphosphon-
ate monomers, it is preferred to employ bis(beta-chloroethyl)
vinylphosphonate in preparing the novel polymers of this inven-
tion since this monomer is a commercially available material,
lower in cost than any o~ the other bis(hydrocarbyl)vinylphos-
phonates. Bis(2-ethylhexyl)vinylphosphonate is also a preferred
-- 6 --
CIP NO. 2 of C-4748
monomer since it gives a product having very desirable physical
properties such as good low temperature flexibility.
Representative C6-C10 alkyl acrylates which can be used
in the practice of the present invention include n-hexyl acry-
late, cyclohexyl acrylate, n-octyl acrylate, 2-ethylhexyl acry-
late, and mixtures of the foregoing acrylates. The C8-C10 alkyl
acrylates are preferred for use, especially the branched alkyl
groups, for example, 2-ethylhexyl acrylate,since such branched
alkyl groups give better physical properties to the resulting
resin.
Mixtures of the respective alkyl acrylates and of the
vinylphosphonates can be used, if desired.
One preferred copolymer from the standpoint of cost and
performance is a terpolymer containing from about 55% to about
80%, by weight, vinyl chloride, from about 10~ to about 35%, by
weight of the C6-C10 alkyl acrylate, and from about 5% to about
25~, by weight, of a bis(C2-C~ alkyl) or(C1-C~ haloal]cyl)vinyl-
phosphonate copolymerized therein. One terpolymer which can be
used to form films having a Shore "A" hardness of about 60 to
about 72 contains about 56% to about 58%, by weight, of vinyl
chloride, about 29% to about 31%, by weight, 2-ethylhexyl acryl~
ate and about 11% to about 13~, by weight, of the vinylphosphon-
ate, e.g., of bis(beta-chloroethyl)vinylphosphonate or of bis
(2-ethylhexyl)vinylphosphonate. For a harder film having a
Shore "A" hardness of about 80 to about 90, a higher vinyl chlor-
ide content is needed. This is easily accomplished by raising
the vinyl chloride content and correspondingly reducing the acryl-
ate and vinylphosphonate contènt. For example a terpolymer hav-
ing a Shore "A" hardness of about 85 to about 95 can contain about
73% to about 75%, by weight, vinyl chloride, about 17% to about
19%, by weight, of the C6-C1O al~yl acrylate, e.g., 2-ethylhexyl
acrylate and about 7% to about 9%, by weight of the bis(hydro-
-- 7 --
~lfi71~
CIP N0. 2 of C-47~8
carbyl)vinylphosphona-te, e.g., bis(beta chloroethyl)vinylphos-
phonate.
The copolymer of the present invention can be formed us-
ing conventional bulk, emulsion, suspension and solution poly-
merization procedures. Suspension polymerization is preferredsince it avoids the problems of isolation of the product from a
latex that can be encountered using emulsion polymerization tech
niques, the heat of reaction is more readily removed as compared
to bulk polymerization procedures, ar.d no solvent recovery is
needed as in solution polymerization.
Suspension polymerization reaction mixtures comprise from
about 20~ to about 45~, by weight, based on the amount of water,
of the above-enumerated monomers in an aqueous reaction medium.
Also included will be from about 0.05% to about 5~, by weight,
based on the weight of monomers, of a suspending agent, such as
methyl cellulose, hydroxypropyl methyl cellulose, gelatine, and
the like; from about 0.005~ to about 1%, by weight, based on the
amount of monomer, of at least one-monomer-soluble initiator,
such as azobisisobutyronitrile, lauroyl peroxide, benzoyl perox-
ide or isopropyl peroxydicarbonate. The polymerization reactionis conducted by heating the suspension containing the above com-
ponents t~ a temperature of from about 35C. to about 75C. for
about 2 to about 12 hours with agitation being applied through-
out the course of the reaction. As is well known in the art, the
use of the more active of the above mentioned initiators will re-
quire use of either a lower temperature or shorter reaction time,
or both, whereas use of the less active initiators may require
more vigorous reaction conditions. If desired the molecular
weight of the polymers can be regulated by adding an effective
amount of a chain transfer agent during the polymerization.
-- 8 --
7'~
CIP NO. 2 of C-4748
Generally from about 0.01 to about 0,1%, by weight of the mono-
mers,will be effective. Representative chain transfer agents
include the chlorinated hydrocarbons, e.~., te~rachloroethane,
trichloroethane and carbon tetrachloride, and mercaptans of the
formula RSH, where R is an alkyl group, e.g., a C1-C1 2 alkyl
group,such as butyl or dodecyl.
If emulsion polymerization is to be employed, the above
descri.bed suspending agent is replaced with from about 0.2-~ to
about 2%, by weight, of an emulsifying agent, such as sodium
lauryl sulfate, potassium stearate, an alkyl benzene sulfonate,
an ammonium dialkyl sulfosuccinate, and the like, and the mono-
mer soluble initiator is replaced by from about 0.1~ to about
1~ of a wat:er-soluble initiator, such as an alkali metal per-
sulfate, perborate or peracetate, ammonium persulfate, perborate
or peracetate, the urea peroxides, hydrogen peroxide, tertiary
butyl hydroperoxide,and the like. If desired, a redox initiator
system such as ammonium persulfate and sodium bisulfite or hydro-
gen peroxide ancl ascorbic acid can also be used as the initiator.
Polymerization is carried out at similar temperatures and over
similar times as those used in suspension polymerization.
If bulk polymerization is employed, the monomers are poly-
merized in the presence of the above-described amounts of the
monomer-soluble catalysts under the same temperature and
time conditions described above in connection with suspension and
emulsion polymerization.
If solution polymerization is employed, the monomers are
polymerized in the presenceof at least one inert or~anic solvent,
such as butane, pentane, octane, benzene, toluene, cyclohexanone,
acetone, isopropanol, tetrahydrofuran or the like. The selected
initiator should be soluble in the reaction medium. The copoly-
mer can either remain dissolved in the solvent at the end of the
g _
CIP NO. 2 of C-4748
polymerization or can precipitate from the li~uid phase during
the polymerization. In the former case, the product can be re-
covered by evaporation of the solvent or by precipitation o~ the
polymer solution by combining it with a non-solvent for the prod-
uct. The same reactionconditions used in suspension and emul-
sion polymerization can be used.
The final product of the present invention can contain, if
desired, various optional additives which are compatible with
the copolymer product and which do not adversely affect the
properties of said product. Included within this class of addi-
tives are those heat and light stabilizers, ultraviolet stabil-
izers, pigments, fillers, dyes, and other additives known to
persons of ordinary skill in the art. A suitable listing of
possible additives which a person of ordinary skill in the art
may use to select appropriate additives, if desired, is given
in Modern Plastics Encyclopedia, Vol. 51, No. lOA, e.g., at pp.
735-754.
The following Examples illustrate certain preferred em-
bodiments of the present invention:
EXAMPLE 1
This Example illustrates the generalized procedure which
was used to form an internally plasticized resin in accordance
with the present invention by suspension polymerization.
The following ingredients were used. All amounts are given
in parts by weight:
Ingredient Amount
Vinyl chloride monomer 100
2-ethylhexyl acrylate 46.5
Bis(beta-chloroethyl)
vinylphosphonate 19.95
Hydroxypropylmethylcellulose sus~
pending agent ~"Methocel" K-35~
from The Dow Chemical Co.) 0.23
20 wt. % isopropylperoxydi-
carbonate in heptane 0.54
Deionized water 423
-- 10 --
B
CIP NO. 2 of C-~748
The following procedure was used to polymerize the vinyl
chloride, acrylate and vinylphosphonate monomers:
1. The suspending agent was dissolved in a portion of
the deionized water and was charged into the reactor along with
the remainder of the deionized water. The mixture was stirred
briefly and the perioxydicarbonate/heptane initiator mixture was
added;
2. The acrylate and vinylphosphonate monomers were added;
3. The reactor was closed, vacuum was applied (approx.
584.2-635 mm. of Hg. pressure) for 10 minutes to remove air
from the reactor, and vinyl chloride monomer vapor was added to
break the vacuum. This operation was repeated once and the vinyl
chloride was charged into the reactor;
4. The agitator was set at 496 revolutions per minute and
the reactor was heated to 50C. until the pressure in the re-
actor dropped 4.2 kg./cm2 from the maximum pressure noted near
the beginning of the reaction;
5. The reactor was vented and sparged with ni-trogen at
a rate of 70.7 cubic cm./sec. for a 44 liter reactor for a per-
iod of 1 hour to remove residual monomer from the product;
6. The reactor was allowed to cool and the polymer par-
ticles were recovered by centrifuging. The particles were dried
in a fluid bed drier using air at 30C.;
7. The dried polymer was milled througll a Fitz mill and
was sieved through a 30 mesh screen.
Three repeats of the above procedure were conducted. The
polymers which were obtained contained from about 57.4 to about
57.7~, by weight, vinyl chloride from about 29.7 to about 31.5%,
by weight, 2-ethylhexyl acrylate and from about 11.1 to about
12.6~, by weight, bis(beta-chloroethyl)vinylphosphonate and had
a relative viscosity of from about 2.74 to about 3.07 when
-- 11 --
~116~g~
CIP NO. 2 of C-4748
measured as a 1~, by weight, solution of the copolymer in cyclo-
hexanone. The feed composition in each case was a 60/28/12
weight percent composition of each of the respective monomers.
The differences were due to minor uncontrollable variations in
the above described reaction conditions.
EXAMPLE 2
This Example illustrates the physical properties of a
series of film formulations made from the copolymer of the pres-
ent invention. The following procedures were used to make each
test sample:
Samples 1-3:
A compressible film formulation was made for each sample
by mixing together the following ingredients in the following
amounts:
(Amount in Grams)
Ingredient 1 2 3
Copolymer of this Invention* 255 255 255
Chlorinated Polyethylene 45 45 45
Epoxidized octyl tallate 15 15 15
Barium Cadmium liquid Stabilizer 9 9 9
Calcium stearate lubricant 3 3 3
Stearic acid lubricant 3 3 3
Calcium Carbonate ~iller 90 90 90
Titanium dioxide pigment ~ 12 12 12
Acrylic Processing Aid ("K-175" sold
by Rohm and Haas Co.) 15 --- ---
Ethylene ~ss~aramide lubricant
("Lubro~EA'~Ysold by I.C.I.
Organics, Inc.) ~ 3 3 ---
Bisstearamide lubricant ("Advawax 240"
sold by Cincinnati Milacron)--- --- 3
*Sample 1 used a 57.4/31.5/11.1 copolymer of vinyl chloride
(VC)/2-ethylhexyl acrylate (EHA)/bis(beta-chloroethyl)vinylphos-
phonate (BB) having a relative viscosity of 2.78. Sample 2 used
a 57.6/30.9/11.5 copolymer having a relative viscosity of 3.07.
Sample 3 used a 57.7/29.7/12.6 copolymer with a relative viscos-
ity of about 2.8.
The ingredients mentioned in the above formulations were
handmix~d and were then milled on a 2 roll mill having the rolls
at 310F. (154C.) and 315F. (157C.), respectively,for Sample
- 12 -
~ .
.~
CIP NO. 2 of C-4748
1 and 157~C. and 320~F. (160C.) for Samples 2 and 3. After
fluxing in the 2 roll mill for about 7 min., the milled stocks
were compression molded at 320F. (160C.) to produce films hav-
ing a thickness of from about 0.038 in. (0.09 cm.) to about
0.048 in. (0.12 cm.) for measurement of the physical properties
according to various standard testing procedures.
Samples 4-7:
Compressible film formulations were formed from the fol-
lowing ingredients:
(Amount in Grams)
_
In~redient 4 5 6 7
Copolymer of this Invention* 300 300 300 300
Epoxidized soybean oil 15 --- 15 ---
Epoxidized octyl tallate --- 15 -__ 15
Barium cadmium stabilizer (liq.) 9 9 9 9
Calcium s-tearate 3 3 3 3
Stearic acid 3 3 3 3
Bisstearamide lubricant 3 --- --- ---
Ethylene bisstearamide lubricant --- 3 3 3
*the copolymer used in Samples 4 and 5 was the same copolymer
used in Sample 1, whereas the copolymer used in Samples 6 and
7 was the same as that used in Sample 2.
The mill conditions for Samples 4 and 5 were the same as
for Sample 1, and the conditions for Samples 6 and 7 were the
same as ~or Samples 2 and 3.
Samples B-ll
.
Compressible film formulations were formed from the fol-
lowing ingredients:
- 13 -
~ 6~~9~
CIP NO. 2 of C-4748
(Amount in Grams)
Ingredient 8 9 10 11
Copolymer of this Invention* 255 255 225 150
Chlorinated polyethylene 45 45 75 150
Epoxidized octyl tallate 15 15 15 15
Barium cadmium stabilizer (liq.) 9 9 9 9
Calcium stearate 3 3 3 3
Stearic acid 3 3 3 3
Calcium Carbonate 90 90 90 90
Titanium Dioxide ~ 12 12 12 12
Fused silica (Cab-O-Sil~ 3 --- 3 3
Ethylene bisstearamide lubricant 3 3 --- ---
.~3isstearamide lubricant--- --- 3 3
* the copolymer used in Sample No. 8 was the same as that used
in Sample No. l; the copolymers in Samples Nos. 9-11, the same
as in Sample No. 2.
Sample No. 8 was milled using the same procedure as that
used with Sample No. 1. Samples Nos. 9-11 were milled using the
procedure for Samples Nos. 2 and 3.
_ mples 12-13:
Compressible film formulations were formed from the fol-
lowing ingredients:
(Amount in Grams)
Ingredlent 12 13
_
Copolymer of this Invention* 150 150
Epoxidized soybean oil 7.5 7~5
Calcium carbonate 45 45
Titanium Dioxide 6 6
Calcium stearate 1.5 1.5
Stearic acid 1.5 1 5
Bisstearamide lubricant 1.5 1 5
*this consisted of 150 grams of a blend formed by admixing 1970
g. of the copolymer used in Sample No. 1, 3988 grams of the co-
polymer used in Sample No. 2 and 5080 grams of the copolymer used
in Sample No. 3.
The samples were milled in accordance to the procedure used
to mill Sample No. 1 with the Xolls for Sample 12 being at (154/
157~C.) and those for Sample 13 at (138/140.5C.).
Table 1 which follows sets forth the physical properties
for these thirteen samples.
- 14 -
~ ~,. ~
~.~
~679~
In r~ ~ ~ ~ ~ ~
r COr--l ~ a~001~ ~O~D r--I
I~ (~) ~ ~ r--lr~
I t~l
~r ~D CO~ C~ 000
CO a~ r--I~r ~ ~DIfl r--l
~D ~ ~DO 11
I r~
I~ ~S) W N ~~O
~ . . . . . ~
C~ r--J 1~ ~D r~ 5)CO r--l
U l N ~ I~r--l ~
I t~l
O ~9 ~ d'CO In
Z ~ ~r~ I Ir--l
t~
r--I (~1 I I
~ CO r--l ~ U~ ~ I~
co ~r~ r-- a~o cr~Ll')I~ r--l
~D~D ~ I~ ~~r
~ I
tn
oO o ~ n o
O a~o t:O 1~~)r--l ~~r r--I
I
r--l
r~
I~I~ ~ o ~ I I I
r--l ~ ~9 ~ ~ ~Dt~l Ul I I I
I t~l I I I
N.
~D
r-l a)
O ~-- ~ a)
~;I LO ~ U~ ~
o~ ~ r~l ~ U~
m ~ ~ ~ ~ h
~ oCO
h
~ ~ ~ ~ m s~
b ~ tJI -- ~) ~1 a) ~ r~
~ b ~)
O (~ a) or--l
:~a) ~ r~r-l E-~r--i ~.) ~ 5-1 ~rl
~ m ~ o ~ ~ o
14 1 ~1 2~ 1 'C) r~
5~a~ r~ r~l
l~U~ ~ In 0\ ~ ~X,!~ (~ C) O
o ~ o o ~a)~ X s~ ~
~r--I ,~ ~ O r--l ~ r~l a) Q~
Pl VU~
--15--
6719~
~) I D ~D N r--l ~ O
~1 I 1` 0 1` 0 N ~r I I I
I r~ N 1--l 1 1 1
u~ o
N I ~ 1- 0 1~ ~
~1 I t` O ~ O N ~r
I ~I N ~_1 1 1 1
O o ~ o ~
r I r--l N N ~D ~ CO ~ ~D ~ ~1
Z ~1 ~1 ~D ~D N N N 1`
U~
r~
~ u~ co o 1~ o r~ ~D
P O C~ Ir) N U ~ ~) ~ ~ ~ ~1
~ r-l N ~ ~ ) O N 1`
tn
c~ o 1~In ~ n o
I o o~ o oo 1~ ~ ,~
D CO ~ Lrl N 00
o
-
~1
' ~I \ ' ~ CS~
o ~ ~ '~
~ 1~
S ~ ~
~ ~ ~ ~ m
E~ m ~ ~ 0 ~ o
U~ ~ o ~ ~ ~ o
o ~~ (d ~ O
~ ~ X,Y a u o
~0 ~ O ,~
o~
--16--
~ t7~ ~
CIP NO. 2 of C-4748
Footnotes:
1. This is the temperature at which the apparent modulus of
elasticity of a specimen is 9491~4 kg./cm.2. It is the end of
flexibility of the sample as defined by Clash and Berg in their
studies of low temperature flexibility. This point can be de-
termined by ASTM D 1043, which is incorporated herein by ref-
erence.
2. This is a measure of indentation hardness and is measured
on the Shore A durometer after 10 seconds (ASTM Test Method No.
D-2240). This instrument comprises a spring loaded indentor
point with a load of 822 grams projecting through a hole in a
presser foot. The device has a scale which indicates the de-
gree of penetration into the plastic beyond the face of the
foot. The scale ranges from 0 (for 0.254 cm. penetration) to
100 (for zero penetration).
3. This is the maximum tensile stress sustained by a specimen
of the resin during a tension test (~STM D-882). The result is
expressed in kilograms per Cm.~, the area being that of the
original specimen at the point of rupture rather than the re-
duced area after break.
4. This is the tensile strength needed to elongate a specimen
to 100% of its original length (ASTM D-822).
5. In tensile testing elongation is the increase in length of
a specimen at the instant before rupture occurs (ASTM D-882).
Percent elongation is expressed as the increase in distance be-
tween two gauge marks at rupture dlvided by the original dis-
tance between the marks, the quotient being multiplied by 100.
6. The Graves test (~STM) was usecl to determine the tear
strengths using specimens 0.10-0.127 cm. in thickness.
7. The ratio of stress (nominal) to corresponding strain be-
low the proportional limit of a material (ASTM-790). It is ex-
pressed in force per unit area.
~. Measured at room temperature after 24 hours. The films werekept in hexane at room temperature for 24 hours, followed by
oven drying in a forced air oven at 50C. for three to four
hours. The numbers give the percent weight loss of extractibles
in the film. Lower numbers are desired.
9. Measured at room temperature after 1 hour. The films were
kept in perchloroethylene for 1 hour, followed by drying in a
forced air oven at 50C. for five hours. The numbers give the
percent weight loss of extractibles in the film. Lower numbers
are desired.
10. The films were placed in a container containing activated
carbon and were heated at 90C. for 24 hours. The volatile ma-
terials were a~sorbed by the carbon. The numbers represent
the percent volatile weight loss from the film. Lower numbers
are desired.
Samples 1-3 which are the internally plasticized resins
of the present invention are all fairly alike in physical prop-
erties. Resin No. 3 is slightly softer than the first two resins.
- 17 -
~1~6 ~ CIP NO. 2 of C-4748
Samples 4-7 show the effects that the addition of two
epoxy stabilizers has on Resin Nos. 1 and 2. The epoxidized
octyl tallate reduces the low temperature flexibility by about
5 to 7C. at a concentration of 5 parts per hundred (based on
100 parts of resin) as compared to the el?oxidized soy~ean oil.
However, the use of the tallate additive effects the physical
properties, e.g., lowers the hardness of the films as well as
the tensile and tear strengths. The presence of these epoxy
stabilizers increases both the light and heat stability of
the resin.
Samples 8-11 show the effect of addition of chlorinated
polyethylene to the resin and should be compared to Sample 5 as
a control. In general, addition of as low as 15~ by weight of
chlorinated polyethylene improves the elongation with only a
slight reduction of other desired characteristics.
Samples 12 and 13 illustrate the physical property data
Eor the internally plasticized resin oE the present invention
processed at two different temperatures. The properties are
essentially the same,which would allow a person of ordinary
skill in the art to use the lower temperature.
EXAMPLE 3
This Example illustrates the mill heat stability of
various internally plasticized resins made in accordance with
the present invention.
Compressible film formulations were formed from the
following ingredients for each of the enumerated samples: -
- 18 -
.7~
CIP NO. 2 of C-4748
(Amount in Gxams)
Ingredient 1 _ 3 4 5
Copolymer of the Invention* 170 85 85 170 170
Chlorinated polyethylene30 15 15 30 30
Epoxidized octyl tallate10 5 5 10 10
Barium cadmium stabilizer (liq.) 6 ~ 6 6
Calcium stearate 2 1 1 2 2
Stearic acid 2 1 1 2 2
Calcium carbonate 60 30 30 60 60
Titanium dioxide 8 4 4 8 8
Bisstearamide lubricant 2 1 1 2 2
Barium-cadmium-2inc-stabiliz~r --- 3 3 --- ---
Phosphite chelator ("Mark C"~
sold by Argus Chemical) --- 1 1 --- 2
* the copolymer used in Samples 1-3 is the same as that used in
Samples Nos. 12 and 13 from Example 2. The copolymer used in
Sample No. 4 was the same as that used in Sample No. 1 from Ex-
ample 2. The copolymer used in Sample No. 5 was a 59 VC/28 EHA/
12 BB copolymer having a relative viscosity of about 2.86.
Table 2 whi.ch is set forth below gives the processing
temperatures in the 2 roll mill, the type of stabilizer system
that was used and comments on the appearance of the film.
-- 19 --
3~ ~I rl ~,' 9 ~
~ o ~ o
u
3 o ~ ~ o a
o o
s~ a) h
a~ , u J- u o
.~ 3 '~
0 4~ ~ 0 4~ ~ o
F
3 ~ 3
a~ o ~ '' o u~ O
mo tn O ~ u ~ ?
a~ o ~ a3 o ~~ ~o 4, ~ 4,
u) O O ~ O O ~ a.
k ~ ~ ,~
~ o ,l ~a o-,~
O " ~ ,~ 4~ -,1o.) ~ ~
a) O-r~ o O-rl ~ ~ ~ 3
3~ o ~o 2 ~O o 3 o
o-~ o ,l ~ o o ~o o
o ~o ~ o .~ :~ ~JJ 3 cJ ~ ~ t~
1 o Q~ o ~1 0
$ ~ a~ O ~ Oo ~ 3 0 ~ 2
h ~ h ,~
~ u~ u~ ~1 ~ u~ ~~ u~
u~ .. .. .. .. ..
. . .. . .. . . ..
(~J ~1 ~ r4 ~ I Q .q ~ I
~sl N ~ O' ~ ~ O (~ O
~-1~rl u~ N Gn ~ N U~
~.,1 ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~ ~ ~ ~ ~ Q)
E~~ C~ X C~ ~ U X u~ S~ X C~ X
~ I O I o O C~ I O O ~ I O I O O C~
rl a~
~0 ~
C~ ~ U
~rl ~ o o o o o
Ul ~a ~ ~, o o o
U~ ~ ~ ~
C~ ~ \ \ \
O ~ ~ C~
~1 ~ ~ ~ U~ U~ U~
Z;
r u~
U~
--20--
CIP NO. 2 of C-4748
Footnotes:
l. Th~ milling was carried out on a two roll mill operated at
the temperature values set forth in Table 2. The temperature
before the slash refers to the front roll, whereas the one
after the slash the back roll~
2. B&-Cd and ~a-Cd-Zn stand for barium-cadmium and barium-cad-
mium-zinc heat stabilizers, respectively. The epoxy stabili-
zersused were epoxidized soybean oil and epoxidized octyl tal-
late. T~e phosphite chelator is available commercially as
"Mark C'~rom the Argus Chemical Co. All parts per hundred
(phr) are based on the resin as loo parts by weight.
EXAMPLE 4
This Example gives the results of smoke measurement tests
conducted in a commercial smoke density chamber modeled after one
developed at the National Bureau of Standards by the Fire Research
Group (See D. Gross, J. J. Loftus and A. F. Robertson, ASTM
Special Technical Publication 422, pages 166-204, 1969). This
chamber contains a radiant heater producing 2.5 W/cm. 2 of heat at
the surface of a 7.62 cm. x 7.62 cm. sample, a propane-air pilot
burner and a vertical beam of light with a photomultiplier tube
detector and microphotometer to record the attenuation of light
by smoke developing in the chamber. During smoke testing, the
chamber is sealed to enclose the combustion products and smoke.
The tests were conducted under the smoldering mode (Table 3) as
well as the flaming mode (Table 4). The values shown in paren-
thesis are from duplicate runs.
- 21 -
7911
r vl N r
H ~ N C~
N N C~ N N N
eu~ u~ ~ ,~
co 0 ~_t ~ N N
~ ~ ~ o r N u~N r( \ r _t~ ~
~r,
O ~:
e H ,~ O '~
H ~ ~> L~ 1 ~1 ,I v N v vl vl
O U~
_t
~0~
H E-l
C~ H
~j H U~ ~5) O N r-~ N ~ ~ ~I C~J O u~
t ~t
H ~ Vl rl vl --' ~ ~ --"
Il C~ 1~ _,
6 ~
~, ~
~_ ~ ~ _~
E~ vl ~ ~ a~ o ~ ~ ~ u~
C~ ~ N N N N ~ r~ N N N N
H
H Q~
v~ ~ ~ O '~ Q~ O ^ ~ O ^
~1 ~ ~: N u~ ~ N Lr~ ~ N u~
O ~ ~~ O ~ ~- 0
¢ æ U~ z u~ z u~
al ~ a) Q~
~I v~ N N N N
Z; ~ V t) U U CJ
O ~ v
,~ O O
H ~ 'a
v~
.C ~J 5 ~1
u~ ~ ~ p,
W ~ ,v~
,~ v~N ~ C~I ~ ~ ~
~1 ~ ~u + ~ ~ v~ ~I ta ~ u~ ~ tq
3 ~ ~ H H H H
--22--
1~67C~
^ ~ O CO 1~~\ CO CO N ~1
F~ ~
o <1 ~
e H ~ ~ C) O {O
H ~ ~O u~
1~ ~ U)
O
~0~
H
~ C.) H ~ ~ U~ co u\ ~ c~ ~ co cr~ O
Q ~s~
U~
a: o ~,
E ~ -~
~ o~ o u~ u~ u~ N 0~ ~O
H ,_ ~I N N N i~ N ~ ~ N N N (\I
V3
~ `
H
H ~ q~ o ~ a~ O ~ ~ O _~
_., ~; m U~ ~ tu U~ ~ ~\I U~
O rQ ~~ O r9 ~~ O
~: z u~ æ u~ z u~
H ~I N N N N
æ ~ u C
o C~
H O O ~ ~ ~ JJ
H `~
u~~ ~ ~ J :~ ~ ?~
W ~ ~ ~ ~1 ~ ~1
~1u~ --1 u~ --1 HN --IN , 1~ ~
U~ C~-1
~+ ~ + J )
P-~.s~ w
U~~ 1~ H H H H
--23--
CIP NO. 2 of C-4748
Footnotes:
1. The polyvinyl chloride (PVC) resin is a high molecular
weight PVC resin developed for calendered goods applications and
is available commercially as SCC-68~from Stauffer Chemical Com-
pany, Plastics Division. The dioctyl phthalate (an external plas-
ticizer) is available under the tradename "6-lo Phthalate" from
Hatco Chemicals.
2. The copolymer of the present invention. This particular sam-
ple contained the same copolymer that was used in Example 2, Sam-
Nos. 12 and 13.
3. Another embodiment of the present Lnvention. This particu-
lar sample contained a 63.4 VC/ 27.4 EHA/ 9.2 BB copolymer hav-
ing a relative viscosity of 2.~9.
4. The maximum specific optical density gives a measure of the
smoke buildup during the test. Lower numbers indicate less ob-
struction of light due to smoke and are preferred. Dm=25, light
smoke; 25-75 moderate smoke; 100-400, dense smoke; 400, very
dense smoke.
5. This gives a corrected value for the maximum smoke genera-
tion per unit weight of sample. Lower numbers are desired.
6. This value represents the smoke generation per unit weight
of material consumed during the burning process. Lower numbers
are again desired.
7. This is an abbreviation for the Limiting Oxygen Index and is
defined as the minimum mole percent 2 content required in an
oxygen/nitrogen mixture to maintain combustion of a vertical~
top~lighted test specimen. Higher numbers are indicative of a
more fire retardant material.
- 24 -
R~3
5~
79~
CIP NO. 2 of C-~748
Analysis of -the data presented in Tables 7 and 8 show
that under smoldering conditions, a film of the internally plas-
ticized resin of the present invention containing no fire retard-
ant additives produces approximately 65-68~ less smoke compared
to a similar externally plasticized film whether or not these
data are based on unit mass of the original sample tested or
unit mass of the original sample consumed during the testing pro-
cess. Similarly, again under smoldering test conditions, a sim-
ilar film containing a fire retardant-additive produces even
better smoke reduction (e.g., 78% reduction) compared to an ex-
ternally plasticized film containing a similar fire retardant
additive. Under flaming modes of burning, the internally plas-
ticized films oE the present invention again show less smoke gen-
eration as compared to externally plasticized film, i.e., approx-
imately 30% less for films containing no fire retardant additivesand approximately 50% for films containing fire retardant addi-
tives~
EX~IPLE 5
This Example illustrates the generalized procedure which
was used to form an internally plasticized resin having a higher
vinyl chloride content than the copolymer formed in Example 1
and to blends of this copolymer with another internally plasti-
cized polymer.
The following ingredients were used. All amounts are
given in parts by weight:
- ~5 -
CIP NO. 2 of C-4748
Ingredient Amount
Vinyl chloride monomer (VCM) 50 lbs. 13-1/2 oz.
2-ethylhexyl acrylate (2-EHA) 11 lbs. 9 oz.
Bis(beta-chloroethyl)vinyl-
phosphonate (BB) 4 lbs. 12 oz.
Methylcellulose sus~ending
agent ("Methocel"~242
from The Dow Chemical Co.) 30 grams
20 wt. % isopropylperoxydi-
carbonate in heptane 85 grams
Deionized water 74.85 kg.
The following procedure was used to polymerize the vinyl
chloride, acrylate and vinylphosphonate monomers:
1. The suspending agent was dissolved in a portion of
the deionized water and was charged into the reactor along with
the remainder of the deionized water. The mixture was stirred
briefly and the peroxydicarbonate/heptane initiator mixture was
added;
2. The acrylate and vinylphosphonate monomers were
added;
3. The reactor was closedl~ vacuum was applied (approx.
584.2 635 mm. of Hg . pressure) for lO minutes to remove air
from the reactor, and vinyl chloride monomer vapor was added to
break the-vacuum. This operation was repeated once and the
vinyl chloride monomer was charged into the reactor;
4. The agitator was set at 351 revolutions per minute
and the reactor was heated to 50C. until the pressure in the
reactor dropped 4.2 kg./cm. 2 from the maximum pressure noted
near the beginning of the reaction:
5. The reactor was vented and sparged with nitrogen at
a rate of 70.7 cubic cm./sec. for a 44 liter reactor for a per-
iod of l hour to remove residual monomer from the product;
6. The reactor was allowed to cool and the polymer par-
ticles were recovered by centrifuging. The particles were dried
30in a fluid bed drier using air at 30C;
- 26 -
7~
CIP of C-4748
7. The dried polymer was milled through a Fitz mill and
was sieved through a 30 mesh screen.
The resin that was produced from the 76% VC/17.3~
2-EHA/6.7% BB feed composition had a 73.6% VC/13.2% 2-EHA/8.2%
BB composition and a relative viscosity of 2.72 when measured at
25C. as a 1~ by weight solution of the copolymer in cyclohex-
anone.
This resin and combinations of the resin with the 57.4
VC/31.5% 2-EHA/11.1% BB resin from Example 2 (Samples 12-13)
were fabricated into film forming compositions by mixing to-
gether the following ingredients in the following amounts:
(Amount in Grams)
Ingredient 1 2 3
Copolymer of Example 2 (Samples
12-13) - 70 60
Copolymer of Example 5 100 30 40
Epoxidized Soybean Oil 5 5 5
Barium Cadmium liquid stabi~zer 3 3 3
Phosphite chelator ("~lark C~Y sold
by Argus Chemical Corp.)
Calcium stearate
Stearic acid
Bisstearamide lubricant
Calcium carbonate filler 30 30 30
Titanium dioxide pigment 4 4 4
The above formulations were calendered into a film on a
2 roll mill, 310/315F.('.54/157C.) for all samples, at 30/42 rpm
after all ingredients had been mixed and fluxed for about 7 min-
utes. The samples were compression molded at 320F. (160C.) to
produce films with a thickness of about 0.09 to 0.12 cm. The
Table which follows sets forth the physical properties of the
samples that were tested.
- 27 -
LO O
4~
¦ ~ ~ D Ct~ Ln ~ 1- 13 ~'
C~O o ~, ~ S Ln
~O
~t) ~1 0
3~R, 5
a) ~ ~
Z ~ ~ ~ ~ Ln CO ~:~ X
~~1 ~r co ~r ~ ~ ~ ~O E~
~ I o~ o ~ n ~ ~ o ~
~1 ~ ~ o~ s~ o
C)~) ~ R
3 ~, s o
~D ~r ~ ~~ ~ ~ S~
L~ Ln 0:) Ln ~O ~ R P
a~ !n ~ ~Ln ~~ O O -
~ ~ ~ h` o LO
00\ o\O
L~O a)
5_1 ~ R~
a~L,'_~ L,~
~30 L,_l O (a
~10 X
O
R~
0~1 S --I O
~R ~ Ll J-
E~ 3
U
~rl rl ~ ~rl E~
~ aJ~) a~ r ~
.~C r ~r-l ~ r l O
ER~i R
U
rl ~ ID
rl ~rl rl td r¦ ~
X ~ ~JS~ ~ ,~
C~O
1 0~ ~ U~ ~ r l
U~ 3 O ~~ O O O ~
~ -~ (D ~ ~) ~ OR, r l
S ~ rl t~ )3 r ¦ Q)
0\ ~ ~X ~ a) R, au r-l
O ~ O ~ ~S S ~ .C
r I S a~ o r-l ~ f3
* X * r~
* ~ * en
* --
~28-
7~
CIP No. ~ of C-4748
The data presented in the preceding Table illustrates
that a variation of the physical properties and hardness of the
flexible vinyl films can be achieved by incorporating the "hard"
and "soft" embodiments of the present copolymer films in vary-
ing ratios in the formulations.
EXAMPLE 6
This Example illustrates that use of alkyl acrylate
comonomers having alkyl groups that contain less carbon atoms
than specified for the acrylates used herein do not function as
internally plasticized resins as that term is used herein.
The terpolymers listed on the Table which follows were
formed by suspension polymerizing the ingredients also listed in
the Table for 13 hours at about 46C. All amounts are given in
parts by weight using as the initiator 10~ by weight of isopropyl-
peroxydicarbonate .in heptane and hydro~ypropylmethylcellulose
(1~ by wei~ht solution) as the suspending agent.
- 29 -
~ o o o u~
~) 3 o
~:~Q
~ ~J
s~ ~ c) ,a
o
~ u~ E-~
-,~ ''''' oU)
.,. ~ ~ ~ ~ ~ ~ " ~, ~.,
.~ ~ OIH
H m
~ U-,~
_
o o a
~ * (~ E
~ *
3 ~ u~
C~o I I ~ I I Q.~: ~ h
IIIIIU~
h ~'Co o-,J ~:
E~ .c
u~ C~ 3
a
h ~ a~
~ ,~
_ ~ I I o o o o ~ ~ C)
~ ~ ~ _ ~ 3
u~ ~ o O U~ td
E~ ~: ~.4 h
a) ~1 ~ E '~
Z O ~ ~ O
~1 o In I I I I S~ h o ~ h
ml ~ I I I I o o ~ o a
,1 ~ Q
H .c ~1 11
U r~ O ~ ,~
a
F~ $ ~ ~u
m Ln ~ o o o Ln a~
~ ~ m ,~ " ~ o
E~ ~ u~
~rl ~-rl 1~
Z ~ Q ~1~ E ~
H ~ ~ 11 ~ O
Q~ a)L( )L~l Lt) LnLr~ Ln m ~ u a)
O ~ E
,, o s~ s~ Ln
3 ~ .
O ~ aJ o
01 0 o o o o o ,~ .~ 3
(~Il')LnItl Ln Lr~ L-) O h ~ ~: ~
5: ~ ~ ~ ~ ~ ~ 'H O ~ 3
o
~q 5~
m m m m m
m m m m m m
0~0 m0~ Op 0,0 0,0
Ln 0\o o o o Ln ~
g ~ Z 3 ~1
op o\ O~o o\o O~o f~i C ~ E E ~ ~1
o o~O o o o o ,1
N Ln~`1(~ ~) r-l ¦> r-l
p:; ~ V ~ h ~
~o~oo~ocP0~0 0\0 0\0 ~ r~ $ ~ u
Ln ,~ o o o Ln ~ P
o
. , . ~ U L
Ln ~D 1~ *
*
--30-
7~D
CIP No. 2 of C-4748
Each of the terpolymers set forth on the preceding
Table was then formed into compressible film formulations using
the procedures described in Example 2 using the following ingred-
ients. All amounts are given in parts by weight.
Ingredient ~mount
Terpolymer resin 100
Epoxidized soybean oil ("G-62',
sold by Rohm and Haas Co.) 5
Barium cadl~ium powder stabilizer
("V-1541"~ sold by Tenneco Chem-
icals, Inc., Intermediates Div.) 1.5
Phosphite~chelator stabilizer
("V-1542", sold by Tenneco Chem-
icals, Inc., Intermediates Div.) 1.5
Calcium stearate lubricant 0.5
Stearic acid lubricant 0.5
Each product was then tested for the various physical
properties reported on the Table which follows:
- 31 -
l~fi'7~3
U~ , o
~o l ,¢ ~D ~ O Ol¢ ~ Q ~ h a) ~ O
Z c~ ~ ~D Z a) ~ o a) ~ o
O (~ Q'~ ~> 0
,Q
a) s
' ~ U S ta 11~ 0
Lt~ (~ ) h
~ ~ ~ ~ (~~ ,1 ~ ,1
Z cs~ Z a) u~ S u~
'~ (~ S U~ ~ o
3 a) ~ u~
m
~ I
aJ ~ u~
. ~s a~ ~ s
o
~r ~ O 0
Z z ~ ~ ~r ~9 Z a~
r~
,-1 ,1 -IJ ~.) U~ O
~S S -rl ~ S~
O u~
m ~I h R Q, Q' ~ -
Ln O ~ ~O ~1 U~ O ~ (~ ~1
~ ~1 o ~ ~ g 41 X
v~ I 1~ ~ o ~1 a~ O 0 5~ 0
41 0 41 Q"a a) S~
1~ 4~ u~ ~ Q, ~:
S,~ ~ Q~
o m
h
~1 ;~ ~ ~ Z o ~ ~a aJ h a ~ Z ~ ~
U~ CJ 4l h
~.
c~ ~ 0 0 k ,1 0 a) a) Q U~
a) z ~ o
Q,
a) ~ o-,~
0 ~ ~ ~ ~ O
Z~ 3 ~ ~ 4~
CO O~ td a) o o t~
Z u~ ~ ,1 ~ h al
O ~ ~ Q, ~ ~ tq
a) o ~ ~
rC ~ ~ ~ ~ ~) ~1 ~ E~ 3
h u~
~1 ~ O ~ O
0 C) ~
o O ~,1 3 ,1 ~ Q,
a) u
N o\O o~
o .-1 0 (;~ 1 o U~ ~ .
u~ 41 ~ 41 ~ a .~
~a o ~ o ~ n-
a.J ~ U ~ o O-1~ O ~
m ~ ~.~ s ~ z ~
a) h ~ X ~ d
c~ ~ s s~ R
m ~ ~ o ~ rn o f~
2, ~ u~ ~ ~ o o so ~
m ~ ~ o ~ u~ -~ ~ c~ ~R U~ ~
s a) a) ~ -~ O Q
O ~ ) O
X ~ ~ O
c-~ IY C~-- o\ U~ ~ Z
-32-
i7~
CI]? No. 2 of C-474~
The data which is presented in the preceding Table
illustrates that use of the lower alkyl acrylates (for example,
the C2 or C4 alkyl acrylates) in a terpolymer of vinyl chloride
and a bis(hydrocarbyl)vinylphosphonate does not yield an inter-
nally plasticized resin, as does use of the higher alkyl acrylates
(for example, the C8 alkyl acrylates), as contemplated by the
present invention.
The foregoing Examples illustrate certain preferred
embodiments of the present invention but should not be construed
in a limiting sense. The scope of protection which is sought is
given in the claims which follow.
- 33 -
