Note: Descriptions are shown in the official language in which they were submitted.
7~
TITLE
Highly Filled Thermoplastic Compositions
Based on Ethylene Interpolymers and
Processing Oils
BACKGROUND OF THE INVE2~TION
Field of the Invention
This invention relates to highly filled blends
and more specifically, it relates to highly ~illed blends
of ethylene interpolymers modified with processing oil.
~ 1~____ o e Prior Art
The use of processing oils with natural rubber
or synthe~ic rubber-like compounds con~aining sulfur,
accelerators, carbon black and other additives customarily
used in the rubber industry is well known. In some
instanc2s in order to ob~ain very high tensile strength
values, fillers are omitted~ On the other hand, it is
known that styrene/butadiene rubber (SBR) compounds, such
as are used to adhere jute secondary backings to carpets,
can readily hold up to 80~ by weight or more of calcium
carbonate filler. Vulcanization or curing enhances blend
~trength.
For thermoplastic elastomeric uses it is
desirable both to avoid curing and to employ fillers to
reduce blend costs, as well as to increase blend density.
Binary blends of ethylene/vinyl acetate (EVA)
copolymer with filler are known as articles of commerce.
The practical limit for addition of a filler such as the
more commonly employed medium density fillers, edg.
CaCO3, bauxite, gypsum, e~c., is about 60% by weight,
even when using a relatively low melt index (higher
molecular weight) resin, or softer, higher vinyl acetate
grades. As filler le~els rise, other properties suffer,
such as melt index (as it drops, extruder pressures
mount rapidly), softness (the "hand" becomes much stiffer),
and elongation (which drops alarmingly). Ultimately, at
about the 70~ filler level, it is not possible to compound
binary EV~/Whiting ~naturally occurring ground limestone~
CaCO3, from Georgia Marble Company) blends as the mixture
, `~
will no longer "flux" in a Banbury*Mixer (the charge
merely stirs- the resin will not "work" as the blades
tuxn, no power rise ensues, the mixture on discharge is
still discrete EVA pellets ln a powdery Whiting mass).
If one were to use a very dense filler, such as BaS04,
approximately 10~ by weight more filler can be added to
binary EVA blends.
Industrial noise and its control are items of
incxeasing concern to governmental, environmental, and
industrial organizationsO Governmental agencies are
establishing noise limits to which workers may be
exposed to protect their health.
From an aesthetic standpoint, noise also presents
problems. Advertisements for "quie~ riding" automobiles
axe ubi~uitous. Manufacturers are attempting to make
other vehi.cles quiet as well--including campers, trailers,
buses, trucks, and off-road-use farm vehicles.
It has long been known that interposing mass
between a sound source and the area to be kept quiet is
an effective means for attaining sound deadening. A
stone wall is extremely effective~-but is no~ often
practical. A sheet of lead is thin, flexible, often
highly e~fective, but costly. The challenge, ~hen, is
to attain a dense, thin, flexible sheet which can be
interposed between a source of noise and the area to be
quietened.
Sheets of thermoplastics or of rubberlike
materials have long been used as sound-deadening means.
To make the sheets flexible, dense, strong t and inexpen-
sive has posed a challenge ~o compounders for many years.For some uses, such as automobile carpet underlayment,
the sound deadening sheet must also be moldable.
Schwartz U.S. Patent 3,904,45b is related to a
me~hod ~or inhibiting transmission of airborne noise
by interpocing in the air space between the noise source
an~ the locatio~ to be insulated a thin, dense normally
sel~-supporting film or sheet composed essentially of
* Penotes trade marlc
;7~
from about 10 to about 40% by weight o~ ethylene/vinyl
acetate copolymer having an average vinyl acetate content
of from about 10 to about 42% by weight and a glass
transitlon temper~ture of at least abou~ 30C below the
average ambient temperature in the air space, and from
about 60 to about 90% by weight of inorganic filler
materials, such as sulfates, carbonates, oxides, etc.
of barium, calcium, ca~mium, etc., ef~ective tO
density greater ~han at least 2 grams per cubic centimeter.
EVA copolymers have been used industrially for
nearly two decades, however, they are not known to be
used in conjunction with processing oils as articles of
commerce. This could well be an outgrowth of the way
EV~ commercialization has proceeded. That is, most EVA
blends are based on EVA/paraffin wax tec~nology, where
paraffin wax weight is often up to ten~times the weight
the EVA present. Furthermore, despite the obvious
savings inherent in using lower-cost, iower-quality waxes,
~uch as scale wax or slack wax, all a~tempts to do this
have failed. The reason was always the same--the oil
content of the wax migrated and destroyed the effective-
ness of the coating or adhesive when the oil reached the
bond or sheet surface. Thus, compounders "knew" that oil
could not be used in EVA blends and technology developed
along other lines.
Rundle U.S. Patent 3~497,375 discloses coating
compositions for wooden concrete molds consisting of
ethylene/vinyl acetate copolymer and paraffinic oil.
There is no filler employed in the coatlng compositions
of this patent.
Monaghan U. S ~ 3,379,193 discloses teeth cover~
made of ethylene/vinyl acetate copolymer in itself or in
combination wi~h mineral oil and, if desired, with fib2rs
and coloring materials. The preferred formulation is
disclosed to be 47~ by weight of ethylene~vinyl acetate
copoly~er, 47% by weigh~ of mineral oil, 5~ by weight of
nylon fibers, and 1~ by weight of titanium dioxide.
;~ 7~'~
German Patent Applica~ion No. 2,319,431 of R~
Nowell et al, published 1973 October 31 discloses sound
deadening composites suitable for use in automobiles which
consist of a highly filled polymer sheet (for example, 300-
1200 or even up to 1500 parts of filler per 100 parts of
polymer) which on its backside is provided with a filler
material sheet, e.g., a polymer foam. Suitable polymers for
use are disclosed to be terpolymers of ethylene, propylene
and a non-conjugated diene (EPDM), polyvinyl chloride (PVC),
mixed polymers of e~hylene and vinyl acetate (EVA), styrene-
butadiene mixed polymers ~SBR~ and mixtures of these materials
with thermoplastic polymers, such as polystyxene and poly-
olefins.
Boyer U~S. 3,010,899 discloses blends of
ethylene/vinyl acetate resin and mineral oil which are
either rubbery or grease like depending upon the pro-
portion of oil to resin and can be used as a substitute
or crepe rubber or as a grease. It is further disclosed
that fillers such as carbon black or finely divided clays
~0 can be added to the rubbery products to increase hardness
and produce materials suitable as floor tile. As indicated
for ~xample in Claim 11, the filler, carbon black t iS
pxesent in a "minor amount" while the oil-ethylene/vinyl
acetate copolymer mixture is present in a "major amount".
In Example 2 an oil-~resin/carbon black ratio of 4 parts
by weight to 1 part by weight is indicated.
Rosenfelder U.S. Patent 3,203,921 discloses
the use of compositions consisting essentially of 73-88%
by weight of a homo- or copolymer of ethylene (which can
be ethylene/vinyl acetate or ethylene/e~hyl acrylate
copolymer), 2-7% by weight of an aliphatic paraffinic
hydrocarbon mineral oil and 10-20% by weight of a mineral
filler, (for example, calcium carbonate, barium sulfate,
etc.) for preparing blow-molded objects such ~s dolls.
SUMMARY OF T~E INVENTION
.. ...
According to the present invention there is
provided a composition consisting essentially of (a)
from about 5 to 50~ by wei~ht of at least one
copolymer of ethylene with at least one comonomer selec-
ted from the group consisting of vinyl esters of
saturated carboxylic acids wherein the acid moiety has
up to 4 carbon atoms, unsaturated mono~ or dicarboxylic
acids of 3 to 5 carbon atoms, the ethylene content of
said copolymer being at least about 60% by weight, the
comonomer content of said copolymer being from an amount
sufficient to provide the desired oil compatibility and
blend elongation to about 40~ by weight, and the melt
i~dex of said oopolymP-r being -from about 0.1 to about 150,
provided that when said copolymer of ethylene is an
ethylene/vinyl ester copolymer said copolymer can con-
tain up to about 15~ by weight of carbon monoxide; (b)
fro~ about 2 to about 15% by weight of processing oili
and (c) from about 50 to about 90% by weight of filler.
The present invention also provides a composi-
tion consisting essentially of (a) from about 5 to about
50 parts by weight of at least one copolymer of ethylene
with at least one comonomer selected from the group consisting
of vinyl esters o saturated caxboxylic acids wherein
the acid moiety has up to 4 carbon atoms, unsaturated
mono-- or dicarboxylic acids of 3 to 5 carbon atoms, and
esters of said unsaturated mono- or dicarboxylic acids
wherein the alcohol moiety has l to 8 carbon atoms,
the ethylene content of said copolymer being at least
about 60% by weight, the comonomer content of said
copolymer being from an amount sufficient to ~rovide
the desired oil compatibility and blend elongation to
about 40% by weight, and the melt index of said copolymer
being from about 0.1 to about 150, provided that when
said copolymPr of ethylene is an ethylene/~inyl ~ster
copol~mer said copolymer can contain up to about 15%
by weight of carbon monoxide or sulfur dioxide; (b)
~S'72~
from about 2 to about 15 parts by weight of processing
oil; and (c) from about 50 to ~bout 90 parts by weight
of filler.
Further according to the present invention,
there is provided the above composition wherein the
filler has sufficiently fine particle size to enable
production of a smooth, continuously extruded sheet,
strand, or tube, substantially free of melt fracture
and such that when said strand is pelletized it yields
pellets that are free flowing.
Further provided according to the present
invention are the above com ositions in the form of
a sound deadening sheet.
5till further provided according to the
present invention are carpets and especially automo-
tive carpets having a backside coating consisting
essentially of the above compositions.
As used herein the term "consisting essentially
of" means that the named ingredients are essential, how-
ever, other ingredients which do not prevent theadvanta~es of the present invention from being realized
can also be included.
5a
D~TAIL~D DESCRIPTION OF T~IE I~VENTION
It has been found that inclusion of a process-
ing oil in highly loaded blends o~ ethylene/vinyl acetate
and filler allows the preparation of considerably higher
filler level containing blends than can be attained in
corresponding binary blends of ~VA-filler. E'urther-
moret~secomponent blends can be prepared employing high
oil content, even in ~he absence of rubbers, elastomers,
carbon black, or other oil absorbing materials. If
10 desired, EVA-base~, non-bleeding blends containing very
high filler levels can be prepaxed employing certain pro~
cessing oil5 according to the ~resent invention.
The ethylene copolymers suitable for the com-
position of the present invention are copolymers with at
15 least one comonomer selected from the group consis~ing OL
vinyl esters of saturated carboxylic acids wherein the
acid moiety has up to 4 carbon atoms, unsaturated mono-
or dicarboxylic acids of 3 to 5 carbon atoms, and esters
o~ said unsaturated mono- or dicarboxylic acids wherein
the alcohol moiety has l to 8 carbon atoms. Terpolymers
of ethylene and the above comonomers axe also suitable.
In addition terpol~mers of ethylene/~inyl acetate/carbon
monoxide containing up to about 15 percent
by ~eight o~ carbon monoxide can also be employed.
~5 The ethylene content of the copolymer is at
least about 60~ by weight and the comonomer content is
from an amount sufficien~ to provide the desired oil
compatibility and blend elongation ~o abou~ 40% by
weight. Generally from about 60 to about 95~ by wei~ht
30 of ethylene and from about S to about 40~ by weight of
comonomer will be suitable. The preferred ethylene and
comonomer lev~l is ~rom abou~ 65 ~o about 85~ and rrom
about lS to about 35~ by weigh~, respectively. A
mixture of two or more ethylene copolymers can be used
in the blends of the present invention in place of a
single copolymer as long as the average ~alues for the
comonomer content will be wlthin the above-indicated
range~
Employing a copolymer containing over 28% non~
ethylenic comonomer (such as vinyl acetate) results in
blends that are less stiff and have lower tensile strength r
while their elongation is increased. The most preferred
level is a}~out 18 to 28 weight percent. Below 18~ vinyl
acetate, the blends become much stiffer, lose elongation,
and oil compatability problems arise. Even blends made
with nonbleeding oils become "oily" as polyethylene
homopolymer is approached.
I~lelt index of the copolymer can range from
about 0.1 to about lS0, preferably from about 0.1 to about
50.
Physi.cal properties, principally elongation,
decline to lower levels when the e~hylene copolymer melt
index is above about 30. Lower melt index ranges~ about
1 to 10, are most preferred to maintain strength.
Generall~ fro~about5 to about50~kyweight of ethyl~:le
20 copolymer ise~loyed in thecompositiono~ thepresen~ inven~ion,
~referably fromabout5 to about30%b~ weight,a~dmostpreferably
from about 10 to about 25~ by weight.
In accordance with the abov~, suitable ethylene
copolymers are such as ethylene/vinyl acetate/ ethylene/
25 acrylic acid, ethylene/methacrylic acid, ethylene/ethyl
acrylate, e~hylene/isobutyl acrylate, ethylene/methyl
methacrylate, and ethylene/vinyl acetate/carbon monoxide.
Particularly suitable copolymers are ethylene/vinyl ace-
tate, and ethylene/ethyl acrylate copolymers.
The oil ingredient of the composition of the
present invention is known as processing oil. Three types
of pr~cessing oils are known-paraffinic, aromatic and
naphthenic. ~one of these are pure, the grades identify
the major oil type present.
Paraffinic oils tend to "bleed" from blends~
Bleeding is normally not clesirable, but could be useful
in specialty applications, for example, in concrete forms
where mold release characteristics are valued.
On the other hand,naphthenic and aromatic oils
are non-bleeding when used in proper ra~ios and are thus
preferable for uses such as automotive carpe~ backsize.
Processing oils~ are also subdivided ~y viscosit~
range. "Thin" oils can be as low as 100-500 SUS (Saybolt
Universal Seconds) at 100F (38C.). "Heavy" oils can be
as high as 6000 SUS at 100~F (38C.). Processing oils,
especially naphthenic andaromatic oils with viscosity of
from about 100 to 6000 SUS at 100F (38C) are preferred.
The amount of oil presen~ in the composition
of the present invention i5 from about 2 ~o about 15~
by weight, preferably from about 4 to about 12~ by weight.
Most preferably when using a filler of mec7ium density, such
as calciuTn carbonate, the amount of processing oil is from
ahout 5 to about 10~ by weight, and when using a filler of
higher densit~, such as ba~ium sulfate, the amoun~ of
processing oil is from about 4 to aboutl0~ by ~Jeight.
Addition o~ processing oil in an amount of
less than about Z% will not have a significant effect.
Processing oil in the amount of in excess of about 10~
will cause the melt index to rise rapidly and the blend
to become much softer. At extremes, for example, at 70
filler, over 15% oil and less than 15% EVA, the oil con-
tent overwhelms the blend as the amount of EVA Dresent
is not adequate to provide "guts" for the blend.
Table I shows the effect of the type of oil
selected upon an important property o the final blend;
i.e., does oil exude from the blend or does it stay bound
firmly within ~he compound? TableII shows how the
oil exudation ratings were arrived at. Table III
su~ari~es t.he composition, pro~erties and origin of
various processing oils. In the Table I comparison five
aromatic oils were evaluated. All or them stayed
fir~ly bound within the compound, even after ~wo weeks
of standing. Further, all six paraFfinic cils tested
showed a marked tendency to exude within a week under
ambient conditions. The test specimens all showed a
tendency to exude, all withln a week, and, in some cases,
on standing overnight.
The naphthenic oils generally showed no tendency
to exude- although in a few cases some exudation
~as noted. Properties of oil~ depend upon two fact~rs--
the procesa and conditions used during refining and the
source of the crude oil used. As ecamples, Tufflo*
2000 (P) and "Tufflo" 2000 (H) are rated b~ the manu~ac-
turer as closely equivalent products. Nevertheless, the
(P = Philadelphia) version did not bleed, but blen~s
based on the (H - Houston) product shor,led asli~httenden-
cy to exude oil. Thus, the purchaser of an oil must
evaluate it ~ith care--and must work closely with the
refiner to ensure constancy of quality. This is
particularly true because industrially obtained process-
ing oils are not "pure" in tllat they nearl~
always contain more than one type of oil. For example,
an "aromatic" oil contains predominantly aromatic ring
structuxes but also usuall~ con~ains substantial pro-
portions of naphthenic xings. Similarly, some naphthenic
oils contain paraffinic oil as well.
Relative proportional shif~s among the oil types ~ill,
of course, change blend performanceO
This is no~ to say that bleeding of oil, per
se, is inherently good or bad. For most uses, bleeding
is not acceptable and must be avoided. However, in
other cases, e.g., a release coating or film intended
for application to a concrete mold or form, a migration
of traces Or oll could pr~ve desirable ln avolding
adhesion Oc the curing concrete to the form.
~ he-comments above apply to smooth ?ressed
sheets, mad2 with a high surface sheen, as would be
produced in industry b~ a conventional combina.ion of
an extruder plus a set of polished rinishing rolls.
* Denotes trade mark
The detection of exudation tendency or d~gree is ~uch
moxe difficult~ if not i~possible, to observe when sh~ets
with roush surfaces are used.
S TABLE I
Exudation Rating As A Function
Of Type And Source Of Oil
Ingredients: EVA ~3*/EVA ~4*(50/50) - 16~ by wt.
_
Oil to be tested - 9~by ~It.
Fille.r - No. ~r~hitLng* - 75~by wt.
ondition: Two weeks at 72F,50% R.H.
~ .
Oil Exudation Rating
Aromatic: Sunde~*790 & 8600T None
Flexon**340 & 391 None
Tufflo" 431 None
Naphthenic: Circosol**450,4240~ 5600 None
Sunthan~*450 & 4240 None
"Flexon" 676; "Flexon" 766 None; heavy,
respectively
"Tufflo" 500 and 2000 (P) None
"Tufflo" 2000 (H) and 6024 Slight
"Tufflo" 6204 Heavy
Paraffinic: Sunpa~*150 & 2280 Heavy
"~lexon" 815 & 865 Heavy
"Tufflo" 60 & 80 Heavy
*d~fined in Table IV
**denotes trade mark
1.0
TABLE II
Oil Exudation Ratin~ For Compositions
~bsorption On
Rating Visual Tactile Pa~er
None No visible Feels dry No ~ransfer to
change paper
~er~ No visihle Dry Smallest percep-
Slight ch~nge kible oil traces
on paper
Slight No visible Borderline Oil transfer to
change ~aper is easily
noticed.
Moderate Surface Slippery Paper beneath
gloss changes feel but no sample is
note~-may visible definitely wet-
look "wet" transfer to under entire sam-
fingers ple area.
Heavy Wet film Hea~y film Paper is thoroughly
readily exists-which wetted. Oil
noticed~oil s~reaks when wicks well beyond
droplets may rubbed. Pin- the area in contact
be visible ger feels with the test
oi.ly after strip.
test.
;'7~
12
TA3LE I I I
Y VISCOSIrYCARBON ATO~IS
p AS~ SUS (2) ~ OL .
TRADE NAME E TYPE SP.GR 100F _lG~F 0~ C~L_~ WT, (3)
"CIRCOSOL"
4240 N 103 0.952525 87 21 39 40 39S
"CIRCOSOL"
5600 N 103 0.955945 135 20 38 42 450
10"CIRCOSOL"
450 ~ 103 0.94 515 52 21 37 42 355
"SU~TPAR" .
150 P 104 ~ 0.88 500 64 4 27 69 530
2280 P 104 B 0.892907 155 4 25 71 720
790 A 102 0.98350085.7 37 28 35 375
"SU~DEX" 101 0.98 - 300 30 22 48
"SUNT~ E"
~50 N 103 0.93 502 52 15 43 42 355
"SUNTHANE"
20 4240 ~ 103 0.8~2206 85 18 ~1 41 400
"FLFX0N"
340 ~ 102 0 O 95 130 38.7 31 41 28
"FLEXON"
766 ~ 104 A 0.90 50358.2 1 45 54
"FLEXON "
865 p 104 B 0.87 33243-61 4 27 69
"FLEXO~"
815 P 104 B 0.9026S0 155 2 32 66
"FLE~ON"
676 N 103 0.931200 72 15 40 45
"FLEXON"
391 ~ 102 0.984010 g2 28 43 29
"TT,rFFLO ~1
P - 0.88 600 68 4 26 7~ 550
"TUFFLO"
P 0.902640 155 4 23 73 72
"~UF FLO "
3~500 (4) ~ 0-94 518 5~ 22 36 42 355
12
2~
TABLE III(cont'd)
CL~SSIFICATION~ D C~L~RACTERISTICS OF PROCESSING OILS
T (l)
y VICOSITY CARBON ATO~IS
P ASTM SUS(2~ % ~lO~.
TRA E ~ E TYPE SP.GR lOG~F 21CF C~ C~l ~p WT.(3)
"TUFELO"
2000(4~ N 0.9~2150 8220 39 41 390
"TUFFLO"
~l~5) A 0.997060 12840 20 40 425
"T[;FFLO"
lC2000 (5) N 0.932110 97 12 38 50 460
"TUFFLO"
6024 (5) N O.S9 175 43 1 50 ~9 345
"TUFFLO"
6204 N 0.911750 91 2 49 4~
0 (1) A = aromatic; N -n~phthenic P = paraffinic. As classified
by supplier
t2) SUS = Saybolt Universal Seconds - 5 x Visco5ity in centipoise
(cp)
(3) asprovided by su~plier
(4) from Philadelphia
(5) frorn Houston
Source of Circosol, Sunpar, Sundex, Sunthane oils ~as Sun Oil
So~lrce of Flexon oils -~as Exxon
Source of Tufflo oils was ~rco
7Z4~
The third essential ingxedient of the composi-
~ion of the present invention is thefiller. The percentage
of filler th~t can be included in the com~osition of the
present inven~ion on a wei~ht basis is primarily a
runction of the density of the filler. Particle size of
the filler has a ~inox effect. Fine par~icle size fillers
generally havea tendency to result in higher blend
viscosities and they are also more expensive. ~9 Whi~ing
which has been used extensively in the present com~osl
tions (about 95% through 32S mesh) represents a viable
midpoint in coarseness, availabilit~ and cost. Most
preferred fillers are calcium carbo~ate, a~d
barium sulfate. Th~ amount of filler Pr~s~nt in the
composition of the present invention is from aboui S~
to abo~t 90% by weight, preferably from about 60 to
about 85~ by weight. Mos~ preferablyt when using a
filler of medium density, such as calcium carbonate,
the amount of filler is from about 65 to about 80% by
weight, and when using a filler of higher densi~y, such
as barium sulfate, the amou~t of filler is from about 70
to abou~ 85% by weight.
When the ethylene interpolymer employed in the
composition of the presen~ invention is an ethylene/vinyl
ester copolymex, such as ethylene/vinyl acetate, and
2S ~Jhen the filler em~loyed in combination therewitn is
clay, such as SUPREX~ Clay, lt is necessary to add oil
to the blend in order to passi~ate ~he clay. Proper
se~uencing of the addition of the ingredients is necessary
to attain success in the mixing operation. Sequence A
30 ~elowr during int2nsive mixi~g will be suc`cess-ul; while
Sequence B may fail, if the EVA/claY mixture is heated
before the clay is p~ssivated bec2use of the decom~osi-
~ion of the EVA copolymer caused by the clay.
Deoom~osition is accom?anied ~v libe~ation o~ anh~d~ous
acetic acid, and discolora~lon o~ the blend.
S~u~nce 3~ Clav - "Y" - Oil ~ lix - EVA ~ Mix.
Se~u2nce B: "X" - Cla~ - EV.~ - Mix - Oil - "Y" - Mix.
*denotes trade mark 14
. . . ...... .. .. .. .. . . .. . . .. ................
In the above illustration, "X" and "Y" may be
either nothing or other fillers, diluents or resins that
do not influence the otherwise proba~le adverse reaction
of the EVA with untreated clay. The abo~e passivation of
clay, in order to enable use of substantial amounts of
clay in ethylene/vinyl ester blends is the subject ~atter
of simultaneously filed patent application Serial
~o. 33~ 898 o~ F. G. Sch~macher.
Polymers, both homo- and co~olymers, other
than the ores referred to above, can also be used to
some extent in c~mbination with the above specified
polymers witho~t significantly interfering with the
advantayes obtained by the present invention. Similarly
other ingredients can also be added to the compositions
of the present invention by a compoundcr in order to
obtain some desired eLfect, such as reduction of cost,
or enhancement of physical property. Accordingly,
extender resins, waxes, foaming agents, antioxidants
etc. that are widely used, particularly in hot melts,
2~ can be included in the compositions OL- the present
in ~rentiOn .
A comm~rcially sized batch-type Banbury or
equivalent intensive mixer is entirely suitable for
preparing the compositions of khe present invention. A
Farrel*continuous mixer ("FCM") is also an excellent
mixing device. In either instance, dry ingredients are
charged in routine fashion. It is convenient in most
cases to inject the oil component directly into the
mixing chamber of either unit as per widel~ used
practice with this type of equipment. A mix cycle of a~ut
3 minutes is generally a~equate for the ~anbury mixer
at an operating temperature usually be~ween 325 and 37i~.
The operating rate for the FCM unit generally ~ill fall
*denotes trade mark
16
within ranges predicted by literature ~repared by the Farrel
Company, Ansonia, Connec~icut. Again, lemperatures between
325 and 375F. are effective. In both cases, a very low
oil level, say about 2-3~, may require higher temperatures,
while oil levels above about 7% may mix well at lower
mixer temperatures~ While not evaluated, i~ is expected
that otner devices for compounding of viscous mixes (MI of
0~1 to 20) should be en~irely satisfactor~7--~u-~ in anv
case, ~rototype trials in advance axe desirable.
Once blends are mixed, routine com~ercial
practices may be used, such as underwater melt cutting
plus drying or use of sheeting plus chopping methods, to
produce a final pelletized product.
Primary use for the compositions of the
present invention will probablybe~n Thesheeting field,
particularly for low cost, dense ! sound deadening struc-
tures. Outstanding characteristics such as improved
"hand", ~drape~, r duced stiffness, and reduced thick-
ness of the extruded sheeting result from the compositions
o the present invention
The blends of the presentinvention can readily
be extruded onto a substrate, such as an au~omotive
carpet, or can be extruded or calendered as unsupported
Eilm or sheet. Depending upon the equipment used, and
the compounding techniques employed, it is possible to
extrude wide ranges of film thickness, fro~ below 20
mils to above 75 mils. While not demonstrated, a film
thickness of even less than 10 mils and ovex 100 mlls
could probably be readily attained. This then provides
industry with an opportunity to vary the amount of sound
deadening to be attained by varying film thickness,
density of blends t ratio of filler load to binder, and
similar techniques well known in the art
The sound-deadening sheet produced may be used
in various ways:
When applied to automotive carpet, blends
described are an effective and economic means to deaden
sound, while also simultaneously serving as a moldable
16
17 ~ '72
suppor~ ror t~ carpet.
When used in sheet form, the blends can be
installed in other areas of an automobile, truck, bus,
e~c ., such as side panels, door panels , roofing areas~
S etc.
In sheet form, blends may be used as dxapes or
ha~gings to shield or ~o surround a noisy piece of
factory equipment such as a loom, a forging press, e~c.
In lami.na~ed sheet form, blends, faced with
another material, might be used to achie~-e both a
de~orative and a functional use--such as dividing panels
in an open-format office.
In the application o. the com~ositions o~ the
present invention in carpets, the initial "soft" carpet
manufacturing stages--~uftins of loops, cutting them to
form a plush if desired, d~eing and drying, and then
storing as u~backe~ "soft" roll goods until ready to
appl~ a back-coating--are entirely similar to well-known
methods as already described in paten~s, e~g.,: S~ahl,
U.S.P. 3,645,948.
Inpreparing automotive car~2t backed with a
sound-deadeniny sheet, several routes may be used. All
are technically feasible~ The most logical routes
would be ~1) and (2~ below, although route ~3) would
also be ~ractical and might be prefer~ed by one who
did not want to invest in extrusion equipment.
Route(l~-prepareanautomotive~type "soft" carpet by
tufting, dyeing, and drying followin~ known ~-r~
TAen, using standard extrusion coa~ing ~echnology, 2pply
first a relati~ely fluid precoating material such as a
high mel~ index EV~ or polye~hylene resin or hot melt
blend in an amount sufficient to bin~ the individual
bundles as disclosed e.g., in Example III, of the above
Stahl patent, and Smedberg U.S.~. 3,684,600. Then to
the still warm and still sof~ precoa.ed c~rpet, apoly
the desire~ amou~ of sound-deadening hot melt b~e~d
1~
1~
by means of a second extruder. Standard nip roll and
chill roll means are used to secure good adhesion of the
main coat to the precoat and to the carpet. The thick-
ness of the combined layers of hot melt will be selec-
ted so as to achieve the desired sound-deadening level,
in addition to moldability,.shape retention ~bility, fuzz
and pill resistance, etc. as ls required by the ultimate
customer.
Route (2)-In place of two extruders, it i5
possible to use a latex precoat, followed by a dxying
oven, which then will ul~imately be followed by an
extruder to apply the sound-deadening coa~ing. Alternatively,
the precoating mëthod taught by Smedberg, U.S.P. 3,684,600,
may ~e employed. In either case, the extrusion step
can be carried out on an in-line basis~ or, alternately,
the sound~deadening coating can be extruded ont~ the
c~arpet in a future operation.
Route (3)- The carpet can be made and precoated
as per Route (1) or Route (2~ above, and then stored.
Sound-deadening shee~ can be made elsewhere by extrusion
or a calendering process in a totall~ independent opera-
tion. Then, the sheet can be laminated to the carpet
by preheating the to-be-mated faces of the car2et and
the sound-deadening sheet by appropriate means ~ovens,
IR heat), and the final structure ass~mbled. Assembly
would take place through applying pressure to the mating
faces, as for example, by a set of nip rolls. This
technology is similar to that taught by Ballard
U.S.P. 3,940,5~5.
Effectively, all o the routes described above
would apply with equal foroe to the preparation of
carpet for flooring uses. The final product obtained
would be different from standard floor-type carpet in
that it would not require a sheet of secondary jute or
synthe~ic scrim, for reasons given above and covered in
the Ballard patent. It would be different rrom
au~omotive carpet primarily because of face-side st~ling
1~
1 9
differences~
Thus, the initial processing steps would be
tufting, dyeing, drying, as described above--followed
by precoating, as described above--followed by applica~
tion of the heavy eoat (sound deadening coat) as
~escribed in Ro~ltes (1) - (3! above.
Surprisingly, it has been discovered khat
when a superfine fille~ is used in compounding highly
filled processing oil modified thermoplas~ic com~osi-
lG tions, rather than the coaxser-ground fillers generally
~mployed for products of this type, the following
benefits result.
1. Par~icles of t~e produc~ are smoother
following extrusion of stran~s and cutting into pellet
formO
2. The bulk densl~y is increased.
3. The smooth pellets hold very ~ittle
water and thUs are easily dried. Compara~ively little
energy input is needed to dry smooth pellets.
4. The pellets which have a smooth surface
do not "bridge," and hence will flow much fas~er under
equal handling stress than do pellets which have rough
surfaces.
5. As a result of the above, manufacturing
~5 rates can be improved, energy inpu~ needed to dry off
pellets is reduced, and need for added labor to unload
rail cars is avoided or sharply lowered.
6. It is anticlpa~ed tha~ extrusions ln
other than round stra~d form will also benefit sub-
stantial~y ~rom a smooth sheet, free of melt fractureeffects.
NoO 9 l~hiting which has been used extensively in
sound deadening compositions (about 95% through 325 mesh,
maximum particle size of at least about 95~ by weight i.s
about 44 microns and mean particle size by weight is about
19
~ 7~
20 microns) often represents a viable midpoint in coarse--
ness, availability and cost. ~s men~ioned abo~e and
shown below, it has bee~ found that a surprising difference
can be attained by use of filler particles which are much
finer than those found in #9 Whiting~ Specifically,
when ultrafine (paint - use) powdered filler such a5
Atomite* or Microfill* #2 is substituted for ~9 Whiting,
the ~inal strand (rod) or sheet-~orm product, upon extru
sion in conventional equipment, will be smooth. Where
~9 Whiting is employed, melt fracture effects can be
severe. By substituting "Atomite", "Microfill ~2" or
an equivalently fine (paint type) filler for the coarser
#9 Whiting (a caulk or putty grade, widely used also for
plastics or elastomer extension), the final thermoplastic
blend will exhibit little or no melt fracture even though
no other changes are made in composition or in extrùsion
conditions.
The particle size o~ the filler employed in
the compositions of the present invention should be
suficiently fine to enable production of a smooth
continuously extruded sheet, strand or tube, substan-
tially free of melt fracture and such that when the
strand is pelletized, it yields pellets that are free
flowing.
Generally, at least about 95% by weight of the
particles of the filler should have an equivalent spheri~
cal diameter smaller than about 25 microns, and at least
about 50% by weight of the particles of the filler should
have an e~uivalent spheri.cal diameter smaller than about
1~ microns. Even better surface characteristics are
obtained when the above 95% and 50% diameters are
smaller than about 12 a~d about 6 microns, respectiYely.
Most preferred surface characteristi.cs are obtained
when the above 9~ and 50% diameters are smaller than
ab~ut 8 and about 3 microns.
Table XIII show5 detailed physical property
dat~ for ~any commonly used commercial fillers. Th~
proper~ies tabulated are based upon literature of
*denotes trade mark
21
communica~ions fromthe manufacturers; but, as changes
will occur due to vaxiations in raw material sources,
equipment condition, and market conditions, those who
work in this field are cau~ioned to contact manufacturers
5 to be cer~ain the products or possible interest reMain
available and ~o obtain tne most recently available
data concerning them,.or newer possibly preferable replac~ts.
21
7z~
2~
TABLE XIII
Typica l Phy ~
Particle Size Information
FillerTrade Name % on
No. ~ :~verage ~ 325 Mesh
(Microns ) (Microns )
"P,tomi~e" ~T-W) 2 . 50 . 5 to 10 practi-
cal ly O
2Gama~Sperse* 3 . 499. 5% ~12 O. 005D6
6532 ~(~.M. ) max.
3Snowflake* ~T-W) 5.01.0 to 20 practi-
cally 0
4Duramite* ~T-W) 142O5 to 25 practi-
cally 0
5Wingdale* (G.M.) 8O499.5% <42 0~2~ max.
6 "Micxofill" #2 ~CC)6.098~ <30 2.5~ max.
7 Drikali~e* (T W~ 5.5 1.0 to 44 traces
8 ~9 Whiting (G.M.) ca.20 -~ 9.0% max~
9 "LC" Filler ca. 25 to 25 -- 15-20~
(G~M,) typical
Calwhite*~G.M.) 5.4 -- 0 n 008%
max.
11 #22 Barytes (T.W.)12.0Up to 60 0.5~ max.
(1) Data are bas~d on manufacturer's literature
25 ~2 ? All are ground limestone except for NoO 11, which
~ barytes. 5upplier code is:
CCC = Calcium Carbonate Company, Marble Falls,
Texas.
GM - Georgia ~arble Company, Atlanta, Georgia.
T-W - Thompson~ Weinman & Company, Cartersville,
Georgi~ .
(3) Relatively coarse fillers are generally specified
by the mesh siz~ of progressively fi~er screens.
The finest scree~ size in general use is 325 mesh;
fine~ scree~ "blind" easily, are hard to clean
wi~hou~ damage, and are llttle used. The rela~ion~
ship be~ween scxeen size and par~icle size is
* denotes trade mark
'7~
23
~iv~r. belGw.
U.S. StandaYd Particle Diameter(a) in
Sieve NO.
100 149 0.149 0.0059
~g 73~7 0~0737 0.0029
27~ 53/3 0.0533 0.~21
325 44.5 0.0455 0.00175
400 38.1 ~.0381 0.0015
(a) Diameter means equivalent spherical ~iameter, i.c.,
the diameter of a sphere having the same volume
as that of the particle. It is measured by
standaxd means which are defined by the Pulverized
Limestone A~sociation.
23
24
In commercial practice, when ~9 ~hiting was used
or instead a slightly coarser grade, "LC filler," was
employed, we found the particles produced by a conventional
melt cutter to be rough when making highly filled blends
of ~he type described earlier. In turn, during com~ercial
shipment, time, vibration, and pressure cause the pellets
to compact and interlock, which requires added time and
labor to transfer the product. Smoother pellets made from finer
particle size filler do not bridge or interlock and t~us are substan-
tially free of unloading problems. A further benefit found when pro-
cessing pellets of t~.e present invention is the ease o~ drying the
final product. Rough pellets from a melt cutting unit tend to hold
subs ~ tial amoun~ of free water in crevices. ~en smooth, dense
pelle~ are produced, there is essentially no way that water can be
entrained. ~Ience, smooth pellets can be dried rapidly with little
energy input ~ comparison to that needed when ~ry~g rough, very
wet pellets.
Similarl~y, when a sheeting die is usedl the
extrudate from blends high in filler often exhibi~ melt
20 ~racture. ~ severe enough, this can cause holes ~o
~orm in the sheet. Use of ultrafine fillers combats
melt fracture, thus providing greater manufacturing
latitud~ when extruding sound-deadening or other types
o sheeting.
The followi.ng examples are qiven or the
~_rpose of ilLustrating the present i~vention. All
parts and percentages are by weight ur.less otherwise
speciied.
Comparative Examples 1~9
. . . _ _
These examples show the increasing dif~iculty
encountered in making highly ~illed binary blends using
EVA resins as the sole binder. All ingredients were
premixed in a one-gallon (about 3.8L) can by shakin~
manually for about 0.5 minutes. The charge was then
added to a Banbury-Type ~aboratory-sized intensive high
shear mixer. Mix conditions used were fluxing for 3
24
2S
mlnutes, at a temperature of about 325-375F (about
160-190C). Compositions and physical properties are
summarized in Table XIII. When a high molecular-weight,
18~ vinyl acetate (VA) containing resin was used,
increasing the filler (CaCO3) level to 65% from 55%
reduced elongation tenfold. A further filler increase
to 72.5% resulted in a mixture which no longer would
flux in a Banbury mixer. The "product" emerged as
unblended, dry ingredients. In similar fashion, use of
a lower molecular-weight, 18% VA containing resin or of
a softer and also lower molecular-weight E~A resin
blend did not enable fluxing in a Banbury mixer at
72.5% filler loading~ ~ddi.tion of filler caused one
other pronounced efect-~the stiffness o the blend
in^reased
7~4
~6
TABLE IV
CO2IPOSITION A~D PHYSICAL PROPE~TI~S OF
EVA -CaCO3 BLEND~S
Ingredients Ex. Cl Ex. C2 Ex.C3 Ex.C4 Ex.C5 ~x.C6
EVA ~1~1) 45 35 27.5 - _ _
~VA #~2) 27.5
EVA ~3(3)
EVA ~4(4)
~9 Whiting (5~ 55 65 72.5 55 65 72.5
Physical
Properties
. . _ ~
Si~ o G~ Blend 1.47 1.59 1 1.39 1.55
Tensile
Strength,
PSI(S) 1050 904 WILL 662 706 WI LL
Tensile
Strength,
k Pa 7240 6230 NOT 4560 4870 NOT
Elongation,
%~6) 455 ~2 34 23
Thickness
o~ Strip, FLUX F~UX
Mils 74 70 68 68
MM 1.88 1.78 1 1.73 1.73
Sti~ness of ¦
Strip, g (7) 160 157 J 99 121
2~
26
27
TABLE IV (cont.)
COr~POSITION AMD PHYSICAL P~OPE~TIES O~
EVA -CaCO3 B~E~DS
Ingredients Ex. C7 E~. C8 Ex. C9
E~A ~
EVA ~(2)
EVA ~3(3) 22.5 17.5 13.75
EVA ~4(4) 22.~ 17.5 . 13~75
,~9 Whiting(5) 55 (,5 72.5
Physical
Propexties
SP. GR. of Blelld1.50 1.60
Tensile Strength
PSI`~) 669 627 ~IILL
Tensile Strength,
k Pa 4610 4320 NOT
Elonga~ion, ~ 25 401
Thickness of Strip, FLUX
Mils 68 68
MM 1.73 1.73
Stiffness of Strip,
g(7) 94 114
footnotes:
(1)18% vinyl acetate, 82% ethylene copolymer; ~.I. =2.5
(2)18% ~inyl aceta~e, 82% ethylene copolymer, M.I. =150
(3)25% vinyl acetate, 75~ ethylene copolvmer; M.I. -2.0
( )25% vin~l acetate, 75% ethylene copol~mer; MoI~
(5)Calcium carbonate, as co~mercial ground limestone;
Georgia ~arble Co.
(6)Te~sile st-ength and elongation measurements made on
Instron~Tester using ASTM Method D1708 at crosshead
speed of 2 in (5.1 cm)/min. Samples are 0.876 ir..
~2.23 cm) X 0.187 in. (0.47 em) in si2e~ at strip
~hick~ess sho~n in table.
*denotes trade mark 27
......... ............................. .......................... ~ ........... .. . .
;7~
28
( )Stiffness of strip measured by placing a 1 in x 6 in
(2.54 cm x 15.2 cm) strip on a platform scale, and
measuring the force required to make the ends of the
test strip meet, at room temperature~
(8)referred to water.
Examples 1-7 and Comparative ~
The blends o~ these Examples were prepared
and their physical properties were determined in ~he
same manner as those of Comparat~ve Examples 1-9~
10 Compositions and physical properties are summarized in
Table V. C-10 has a relatively low weight ra~io--1.8--
of filler to organic binder. When the ra~io is raised
to 2.6~1, as in C-ll, the blend will not flux~ as
noted earlier. Howeverf as shown in Example 1, at the
15 identical filler loading~ after having replaced part of
the expensive resin with an inexpensive processing oil,
a truly surprising result was obtalned- the mixture
fluxed well in the Banbury mixer. E~en more surprisingly
the blend of Example 2, which represents a further
20 increase in filler/resin ratio, (4.1/1) not only fluxed
t~ell, but had properties of definite practical interest.
~or example, for comparison of proper~ies o two sound-
deadening sheets, it is important to compare ~hem on an
equal ~eight basis. That is, the two sheet density
25 values, in lb/~t2, (oz/yd2 or g/m2) should be equal or
as close as is reasonably possible. Thus, sheeting
or Example 2 was deliberately made thinner than that
for C-10, to attain equal sheet density
(70 mils x 1.59 = 61 mils vs the ex~erimentally-measured
58 mils, or within O.OQ3 in~ of goal thickness). Note
that the stiffness of E~ample 2 sheeting is only about
1/3 of the s~ifness of sheet from blend C-10, and
still has tensile and elorlgation properties which remain
35 in a commercially useable range.
'7~>~
29
A second comparison was made to learn whether
this surprising finding was limited to high molecular-
weiyht polymers such as that used in Examples 1 and 2.
Examples 3 and a, when compared to blends C-12 and C-13,
sho~ the same effects even though the EVA g,ades used
are equivalent to a much softer copolymer (higher VA
content) which also has a lower molecular weight.
Examples 5, 6, and 7 show blends with various
combinations of filler, resin and oil and different ratios
10 of filler to resin. The resulting ~roperti changes i'LUs-
trate t'.~e latitude available to the for~llator in
seeking a desired balance of properties.
~5
29
TABI,E V
_
COMPOSITION AND PHYSICAL PROPERTIES OF
EVA -CaCO~- PROCESSING OIL BLENDS
f
In~redientsEx.C10 E~. ~1 E~ . 2 E~. C~ EX.C13
E~. XI 35 2?.5 20.5 17.5
EVA #3 ~ 17.5 13.75
EVA ~4 ~ 17.5 13.75
#9 Whiting65 72.5 72.5 72.5 65 72.5
"CIRCOSO~'
4240(1) ~ 7 10 - -
Filler/Organic
Ra~io 1.8/1 2.6/1 2.6/1 2.6/1 1.8/1 2.6/1
Filler/Re~in
Ratio 1.8/1 2.6/1 3.5~1 4.1/1 1.8/1 2.6/1
Physical
Propertles
SP. GR. of
Blen~1 1.59 '1.821.81 1.60
20 Tensile
Strength, PSI 904WILL649 636 627 WILL
Tensile
Strengt~ k Pa 6230 447Q 4390 4320
Elongationr ~ 42NOT 21 23 401
25 Thickness ~LUX ~LUX
of Strip,
~ils70 59 58 ~8
MM1.78 1.50 1.47 1.72
Stiffness of
Strip, g 157 89 57 114
7~
,
31
TABLE V (cont.
... . ..
COl~lPOSITION AND PHYSICAL PROPERTIES OF
EVA -CaC03- PROCESSING OIL BLENDS
, ~
!lgred i .~ ~s ~ . 3 _x . ~s Ex. 5 E,~. 6 Ex
~ ~ 7 Z~
EVA " 3 9 . 7 ~ 8 r 7 5 9 ~ 2 5 1 0 ~ rj
EVA ~4 9.75 8.759.011.25 10.5
~9 Whiting 72 . 5 72 . 575 .070.0 70.0
10 "CIRCOSOL" 4240tl) 8 10 7.0 7O5 8.0
Filler/Organic
Ratio 2~6/1 2.6/13/12.33/1 2.33/1
Filler~Resin
Ratio 3.7/1 4.1/1 4.2/1 3.1/1 3.33/1
Physical
Properties
,, ~
SP. GR. of Blend 1.8L 1.821.871.76 1.76
Tensile Strength,
PSI 475 410585 557 488
Tensile Strength,
k Pa 3280 283040303840 3360
Elongatlon, ~ 27 3319 37 38
Thickness
o Strip,
~ils 59 S~59 62 62
MM 1.50 1.501.501.57 1.57
Stiffness Of
Strip, g 53 4573 65 62
(1) A naphthenic processing oil available from Sun
Petroleum Products Company. The CQmposition for
the oil as given by the supplier is 39~ naphthenic
carbon~ 40~ paraffinic carbon, and 21~ aromatic
carbon. Viscosity at 100~. is 2525 SUS. Specific
35 gravity is 0.9490.
7 ~ '~
32
Examples 8-11
~hiting (CaCO3) is a very common and cheap
filler with a density of about 2.7 gJcm3
One might elect to employ a very dense, but more costly,
filler to achieve a special purpose. Table VI illuskrates
some ways the new technology can be employed with a
dense filler. Blend pr~paration and determination OL
physical properties followed the procedure outlined in
preceding examples~ Example 8 shows a blend which
contains 75~ whiting by weight--or a~out 51% hy volume.
Examples 9 and 10 show the results when barytes is used
instead, on a ~imple substitution basis, by weiqht.
Example 11 shows properties a-tainable, when barytes is
substituted for whiting, by volume~
These changes are very significant in specialized
uses, e.g., sound-deadening sheeting or backing. For
example, the compounder has several choices:
(a) For maximum weight a~ equal coating
thickness, ~xample 11 would clearly prove superior.
(b) For equal weight at minimum coating thicX-
ness, ~xample 11 woulcl again prove superior.
(c) Conversely, where maximum coating thick-
ness is desired, at a given weight per unit area,
Example 8 would ~rove best.
The data summarized in Tab'e VI were delibera
tely generated in a way to produce nearly equal weights
per unit area. If instead the test plaques had been
m~de at equal thickness, the values noted or relative
stiffness would change markedly. This represents another
option available to one skilled in the art to practice
the present invention, whereby a radical shift in goal
pro~erties can be securod. In using the above data, it is
importa~t torealize thatsmall shi~ts in thickness or in
methods of sample preparation can cause variations in
measured values without departure from the essellce o~
the invention.
32
33
TABI.E VI
CO21POSITION AND PHYSICAL PROPERTIES OF
EVA - CaCO3 or BaSO4 - OIL BLENDS
IngredientsEx~ 3 Ex. 9 Ex. 10 Ex. 11
..... . . . _ ,, _ ___
EVA #3 10 10 8.75 6.1
EVA ~4 10 10 8.75 6.1
~ Whiting 75 _ _ _
Barytes(l) - 75 75 82.5
"CIRCOSOL" 4240 5 5 7.5 5.3
Filler, ~
by Volume 51.3 39.5 39O5 50.7
Physical
_o~erties
SP. GR.
of ~lend 1.87 2.32 2.28 2.67
Tensile
Streng~h, PSX685 555 345 229
Tensile Strength,
k Pa 4720 3830 2380 1580
Elongation, ~18 700 561 68
Thickness
o Strip,
Mils 58 47 48 40
~ 1.47 1.19 1.22 1.02
Stifness of
Strip, g 84 34 25 24
(l)A heavy filler having a de~sit~, of about 4.4
a/cm3 consisting primarily of BaSO~, obtained from
commercial source5. For Example 9, ~22 Barytes from
Thompson, Weinman was used. For Examples 10 and 11,
Dresser Industries ~85 Barytes ~as used. For all
practical purposes, the mate.rials are considered to
be in~erchangeable.
2~
34
Examples 12~13 and Com~arative Example 14
Following the procedure of preceding examples
blends were made with E/EA copolymer in place of the
EV~ copolymer. The results obtained ~Table VII) were
similar to the ones obtained with EVA copolymer.
The addition of"Circosoll' 4240 to a binary
blend enables use of a much-increased filler loading,
while maintaining a praciical degree of tensile strength
and elonga~ion characteristics and while appreciably
reducing ~he stiffness of the final compound.
~0
34
TABLE VII
COr~lP~SITION AND PHYSICAL PROPE~TIES OF
E/EA -CaCO~- ~IL BLENDS
Ingredlen~s Ex. C-14Ex. 12 E~. 13
~ _ _ .... .
5 E/EA(l) 45 20.2 17
~9 Whiting 55 72~5 75
"CIRCOSOL" 4240 - 7.3 8
Physical Pxo~erties
Sp.~R~ofBlend 1.46 1.76 1.83
'l'ensile Strength,
PSX 715 55~ 500
Tensile Strength,
k Pa 4930 382G 3450
Elongation, % 73 15 15
ThicknesS
of Strip,
~ils 75 61 59
MM 1.90 1.55 1.50
Sti~fness
o~ St~lp, g 1~1 94 95
(l)Ethylene/ethyl acrylate copolymer, grade DPDA 6182
NT, obtained from Union Carbide Corporation, contains
about 16~ ethyl acrvlate, about 84~ ethylene, and
has a melt index of about 1.5.
7~
36
Examples 14-l9
These examples illustrate the use of different
interpolymers in practicing the p~esen~ inventionO Pre-
paration and evaluation of the blends follo~d the
S procedure of preceding examples.
Compositions and physical properties are
summarized in Table VI~I.
~ rhe blends of these examples are free of
surface tack and exuded oil at ambient tem~erature.
One skilled in the art can readil~ make a wid~ assortnent
of changes, such as.
(a) Using blends of interpolymers.
~b) Using alternate fillers.
(c) U~ing other oil ingredients, such as
aromatic or paraffinic oils, in plac~ of all or part of
the naphthenic oil used in Table VIIIexamples. It is,
o~ course, possible to use oils of higher or lower
viscosity to secure special effects.
(d) Adding other ingredients, such as waxes,
rubbers, elastomers, tackifiers, plasticizers, ex~enders,
resins, etc. such as are widel~ used in compounding of
hot melts and extrudable compositions.
3~
36
37 ..~.~ 5 7~ A ~
TABLE VII r
COMPOSITIOM AND PHYSICAL PROPERTIES OF
BLENDS OF ETHYLENE-INTEXPOLYMERS, CaCO3 AND OIL
5In~redientsEx.14Ex.15 Ex.16Ex.17 Ex.18 Ex.19
E/IBA #l~lJ20.2
E/IBA #2(~ ~ 20.2
E/~$~A ~1(3) - ~ 20,2 - - ~
E/MMA #2(4~ - - _ 20.2
E~A #3 - - ~ ~ 10.1
Terpolymer
~1~5~ 10.1
Terpolymer
#2(6) _ _ _ ~ _ 21
#9 Whiting72~572.5 72.5 72.5 72.5 70.0
"CIRCOSOL"4240 7.3 7~3 7.3 7.3 7 n 3 9 ~ O
SP~GR. of Blend 1.84 1.81 1.81 1.84 1.85 1.74
Tensile
Stxeng~h, P5I 227 536 579 349 381 546
Tensile
Strength, k Pa1570 3700 3990 2410 ~63~ 3760
Elongation, ~ 50 23 22 46 34 63
Thicknes~
of Strip,
Mil~ 5~ 5~ 59 58 58 62
MM 1.~7 1.50 1.50 1.47 1.q7 1.57
Skifness
of Strip, g24 73 71 37 52 56
(1) ethyl~lle/i~obutyl acrylate copolymer, 32~ isobutyl
acrylate, 68% ethylene, 1~7 MI.
(~) ethylene/isobutyl acrylat~ copolymer, 20% isobutyl-
acrylate 80~ ethylene, 2.5 ~I.
(3) ethylene/methyl methacxylate copolymer, 18% methyl
methacrylate, 82% ethylene, 2.2 MI.
(4~ ethylene/methyl methacrylate copolymer, 31~ methyl
methacrylate, 69% e~hylene, 7.2 ~I.
37
38
Table VIIIfootnotes (cont.~
(5)ethylene/carbon monoxide/vinyl acetate terpolymer,
65.5% ethylene, ll~ CO, 23.5% vinyl acetate, 35 MI.
5 (6)ethylene/vinyl acetate/methacrylic acid terpolymer,
74~ ethylene, 25% vinyl acetate, 1~ methacrylic
acid, 6 MI.
38
39
Examples 20-23
,~ These examples illustrate how the melt index
of the blends of the present invention can be controlled
over wide ran~es by the amount of oil ernployed. Com-
positlons and results are summarized in Table IX. ~elt
index is of substantial prac~ical importance to those who
extrude cornpounds into sheet form or mold it into
appropriate shapesO By proper control of melt index,
optimum extrudate properties can be secured, or properties
can be matched to ~he capability o F available equipment.
.
: '
_~ 1. IJ'
EFFECT O~ INCREASING OIL CONTENT ON THE
_ MFLT INDEX OF THE BLEND
~ ents_ ~x 20 Ex. 21 Ex. 22Ex. 23
S Base Compound~l) 100 98 96 94
"CIRCOSOL" 4240 - 2 4 6
Melt Index O~
Blend(2) 1.79 3.39 4.90 9.65
(1)
Consis~s of (a) 20% of EVA copolymer having 25~ VA,
75% ethylene, & 2MI; (b) 4~O of EVA copolymer having
7.5% VA, 92.5% ethylene, ~ 1.2MI; (c) 6% of
"CIRCOSOL" 4240 and (d) 70% o~ ~9 Whiting.
(2)Determined by ASTM Method D 1238 , at 190C
572~
41
Exam~le 24 and Comparative Exam~le C-15
The blends of this ~xample were compounded in
a laboratory-scale Banbur~ mixer for convenience, as
previously described, and were then processed into sheet
form in a conventional two-roll mill. To make test
plaques or sheets, the desired amount of blend would be
weighed, placed in a laboratory-scale heated press, and
pressed (between smooth release sheets of Teflon~ fluoro-
carbsn resin) in a die of appropriate thickness. For
convenience, the present die had an openlng of 6" x 6",
was cut from sheet: stock of 58 or 65 mils of thickness,
depending on blend density, and was charged in most
instances with ~3 gxams of resin blend. This corresponds
to 5 lbs./yd.2, a commonly used sheet weight for automotive
carpet use. A typical cycle was:
(1) Place a Teflon~ sheet on lower press platen
or on top of a smooth steel ~aseplate if the pLaten ls not
truly smooth.
(~) Place an 8" X 10" die plate (6" X 6" opening~
atop the Teflon~ sheet.
(3) Put 63 g. of resin in the cavity. (1-2
gxams surplus may be needed as some blend may ooze out
during pressing).
(4) Place a Teflon~ fluorocarbo~ sheet atop
the resin. Add a smooth steel upper plate if the platen
is not truly smooth.
(5) Heat the press to 175C.
(6) When the press reaches 175C., slowly pump
the press closed to a total pressure of about 12,500 pounds
(150 psi, approximately).
(7) After 2 minutes, raise the ram pressure to
50,000 pounds (600 psi, approximately)~ and hold the
pressure and temperature constant for about 1 minute.
(8~ Shut off heat and cool press to ambient
temperature with ram in closed position.
(9) Release pressure, remove sample, and cut to
appropriate shape for further testing.
~1
- - - - - ~ - - - -
42
(10) Age samples overnight at 50~ RH and
72F.
In evaluating highly filled blends, great
caxe and good technique must be used in making all
samples, as surLace imperfections will cause wide
variations in measurements of tensile strength and
elongation.
The composition of this Example, i.s ~iewed
as preferxed and as a logical starting point for a
compounder because it offers an excellent balance of
proper-ties (cf. Table X). For example, the tensile
stren~th value at 550 psi ~3790 kPa~ is high enough for
an~i.cipated uses for filled thermoplastic blends. Further,
~he elongation noted, at 455%, is outstanding ~or a
highly filled hlend. Despi~e these excellent properties,
the stif~ness value for the compound is only 76 g. vs.
the high 118 g. for the oil-free comparative blend,
C-15. As this balance of properties indicates,.the blend
o~ Example 24 can be readily prepared from its ingredients
and also can be readily extruded into sheet form. On
the other hand, Blend C-15, compared to Blends C-12 and
C-13 (Table V), has about reached the ultimate upper
limit fox filler load on an oil-free basis. The com-
pound tensile strength has jumped sharply,andelongation
has dropped sharply vs. Blend C-12. Physical propexty
data for Blend C-15 were no~ easily determined, as it
was ~ery difficult to make good, reproducible ~est
coupons using so high a filler loading without inclusion
of oil.
The above preferred blend does have a drawback;
it is possible to produce more highly filled compositions,
with an e~ual or hi~her oil content, nd thus save sub- ~
stantially in raw material costs at the expense of
ph~sical properties. For example, compare the physical
properties of the blend of Example 24 with the properties
o~ blends o~ Examples 3 through 7 in Table V. The
latter blends, while still useful for man~ purposes,
42
43
have about l/3 less tensile stren~th and about l/10 the
elongation--surely a major reduction. However, because
EVA copolymers cost over 50¢/pound vs. less than 10~/
pound for oil and about a penny per pound for filler,
it i5 readily ap~arent that many users will want to
pursùe the highest possible filler level aggressively.
This is particularly true for automotive and other sound-
deadening sheet, which depends upon mass for i~s effective-
ness and often does not require great blend strength.
Thus,itiS likel~hatmany industrial users will take the
above l'preferred blendl1 and reduce its excellent tech-
nical properties ~o a lesser level which will still be
technically adequa~e for their uses and will be much
more attractive from a competitive economic viewpoint.
A skilled compounder will realize the trade-offs and
options open to him in reducing performance to reduce
~xice and can vary substantially the blends provided
in the illustrative examples without departing ~rom the
spirit of ~he invention. Compounders can also elect to
vary blend properties by substituting other grades of
EVA copolymer for all or part of the EVA #3 content.
For example, use of an EVA copolymer having a lower VA
content or a lower MI or both, as shown in the blends
of Examples 20-23, (Table IX), will provide a stiffer
blend with improved resistance to deformation at tem-
peratures above ambient. Similar changes can of coursebe effected by adding small amounts of unrelated resins,
rubbers, elastomers, extenders, etc. without departing
from the spirit of the invention.
3S
43
5~
44
TABLE X
PREFERRED SOU`~D-DEADE~IN~, COMPOSITION
_,. _,. . . . . .
Inqredients E~ample 24 Example C 15
EVA X3, % 26.5 33
"Circosol" 4240, % 6.5 --
~9 r7~iting , ~ 67.0 67
Ph~sical Propexties:
Sp. Gr. OL Blend 1.72 1.72
Tensi le Strength - psi550 895
- kPa3790 6170
Elonga~i~n,% 455 gg
Thickness of Strip, mils 65 S5
Thickness of St~ip, ~m1.65 1.65
Stiffness of Strip, g 76 118
44
Exam~les 25-26 and Comparative Example 16
These examples show that even readily fluxable
EVA/filler blends having a rela~ively low filler content
ean be usefully altered bY addition of small amounts of
S a processing oil. Compositions and results are su~marized
in Table XI. Blend ~-16, for example, is a ve.ry stiff
compound with good elongation and with a high tensile
strength. To make the blends of Example 25 and Example
26, the resin content was reduced by 5% and 10~,
respectively, and replaced by processing oil. The
elongation values and the densitv were ~irtually unchanged.
However, the blend became su.r~risingly softer, yet
retained a good tensile strength value. Thus, addition
of oil to a ~illed EVA system conerred benefits.
'7~
46
TABLE XI
COl-iPOSITION AND PHYSICA!J PR~PF:RTIES
EVA -CaC03 -OIL BLl~r)s ~T ~ 5 % FILLER I.OAD
.. _ _ , .. . . . . . .
Ingredlents ~'x. _-16Ea~. 25 Ex- 2.6v~
EVA ~1 45 40 35
~9 Whiting 55 5S 55
"CIRCOSOL" 4240 - 5 10
Ph~ical Prope_ties
SP. GR. of 13lend 1.46 1.48 1.47
Tensile Strength, P5I 935 618 491
Tensile Stxeng~h, kPa6450 4260 3380
Elongation, ~6 3 9 6 3 4 83 8 4
Thickness of Strip,
Mils 74 74 74
ITm 1.~8 1~8 1.8~
Stiffness of Strip, g 153 99 72
46
~ `
47
~ F ~
The composition and physical properties of
the blends of ~hese exam~les are summarized on Table
XII~ The blends were made with a ~ixed pxoportion of
~VA resins plus fillers ~ollowing the procedure of
preceding examples. ~hile the percentage of oil present
has been held constant, the type and viscositie5 have
been varied.
Of the 9 oils tested in this series
the aromatis oils showed no tendency to exude,
while the paraffinic oils exuded. Of the naphthenic
blends, only the Example 28 sample showed an exudation
tendency. This sample contained "Fle~on" 766, which
has 54~ paraffinic content, 45~ naphthenic, and 1%
aromatic. By contrast, the other three naphthenic oils
had a paraffinic oil con~ent of 42~ or less. Thus, the
need to carefully examine the type o~ oil s~lected is
evident to ensure attaining the desired surface charac-
teristics (i.e., dry or oily) for the final produc~.
A11 of the blends had about the same specific
gravity, and thus the same thickness strips were com-
paxed. Results show the highest stifEness resulted
when the highes~ molecular-weight oil was used. Further,
scouting tests (not tabulated) showed that the blends
made with low molecular-weight (low viscosity) oils
had better resistance to flexing at temperatures below
zero degrees Fahrenheit.
~0
47
7;~
48
TABLE XI I
COMPOSXTIOM AND PHYSICAL PROPERTIES
OF EVA CaC03-OIL BLENDS CONTAINING
DIFFERENT TY~ES OF OIL
.
Ingredients: EVA ~3 & ~4 = 8% of each
OIL = 9%
FILLER (CaC03 ) =75%
(1) Ex. 27 Ex. 28 Ex. 29 Exo 30 Exo 31
T~7p~ ~7f Oil C450 (N)F7~6 (~)C4240(N)C5600 (N) F340 (A)
Physical
Proper~ies:
.. . .
SP . GR . o f
Blend 1. 87 1. 86 1. 88 1. 87 1. 87
15 Tensiïe
Strength, PSI 431 422 397 477 385
kPa2~72 2910 2737 3289 26i4
Elongation, % 15 22 19 21 21
Thickness
20 oE Strip,Mils 58 59 59 58 58
~run 1.47 1.50 1. 50 1.47 1.47
Stiffness
of Strip, g 47 45 40 55 46
Exudatiorl .
25 Rating NONE HEAVY NO~E NONE NONE
O
48
2~
4g
TABLE XII
COl~lPO::)ITION AND PHYSICAL PROPERTIES
OF EV~-CaCO3-OIL BLEWDS CONTAINING
DI~FE~ENT T~?E.S OF OII,
Ingredients: Æ-\IA ~. 3 & s4 ~ 8% of each
_
OIL = 9%
E~ILLER ~CaC03 ) =75~
Ex. 32 Ex. 33 Ex. 34 Ex. 35
T~rP~ Of C3il(l) 579n (~)S~500T(A) T60(P) T80 (P)
- Physical
Proper~ie s:
SP.GR. of
Blend 1.88 1.88 1.87 1.85
Tensile
Strength, PSI 560 505 463 401
kPa 3861 3482 3192 2765
Elongation, % 18 22 24 18
Thic}cness
o~ Strip, ~ils 58 58 58 58
lrun 1.47 1.47 1.47 1~47
Stif fness
of Strip, g 63 60 47 50
Exudation
Rating NONE NONE HEA~ HEAVY
(1) K~y is:
C = "CIP.COSOL"
3 o F = "FLEXON"
S = " S U~IDEX "
T - " TUFFLO "
(N) = NAPHTEIENIC
~) = ARO~IATIC
3 5 (P) = PAR~FFINIC
49
7~
,
Examples 36-44 and Comparati~e_Examples 17-18
These examples are summarized in Table XIV
Comparative ExaMples 17-18 sh~w the characteristics of
pellets o~tained when highly filled blends are made
using relatively coarse fillers.
Sample Preparation:
All ingredients were premixed in a one-gallon
(about 3.8 1) can by shaking manually for about 0.5
minute. The charge was then added to a Banbury type
la~oratory-sized intensive high-shear mixer. Mix con-
ditions used were fluxing for 3 minutes at a temperature
of about 325-375F~ (about 160-190CC.). ~nless
indicated specifically to the contrary, all blends
made contained 7205% of the filler to be evaluated,
plus 20.2% of a blend of EVA resins and 7.3% of a process
oil, as identified in Table XIV.
The hot, fully fluxed blend from the Banbury
mixer was then passed through a standard-type two-roll
mill to ~r~ a thin sheet (thickness = about 2 to 3mm).
~ Ater cooli~g, the sheets in turn were reduced to small
chips which could readily be fed to a conventional
extruder. Our tests were made using a co-rotating twin-
screw Werner~Pfleiderer* extruder fxom which the product
emerged as two about 3/16" diameter strands. These were
water-cooled, and then chopped by means of a Cumberland
Cutter into pellet form (right cylinders of about 1/8 X
1/8 inch`. Before the pellets were chopped, the strands
fed into the cutter were blown with a stream of low-
pressure air to blow off as much water as possible.
The pr~duct pellets were evaluated at once ror relative
degree of water content, prior to tray-drying the pellets
under ambient conditions.
After dxying of the pellets, their principal
physical properties were evaluated:
3S Visual Rating of Extrudate ~Strand Smoothness~;
This was rated visually and by touch on uncut strands.
A ra~ing of 1 means the strands are smooth, round, and
*denot~s trade mark
essentially free of surface flaws. The sur~ace is so
smooth that water droplets are readily removable by
simple means such as an air stream. A rating of 5
indicates the strands are extremely rough, jagged, and
cannot be dried by a simple, quick air-blowing step.
The rating system used is described in detail in Table
~V .
Pellet Water Level: On emerging from the
Cumberl~nd Cutter*, pellets cut from fine-filler-contain-
ing smooth strands are dry to the touch. By contrast,
*denotes trad2 mark
7~
52
TABLE Vrv
EFFECTS OF FILLER TYPE ON THE
PROPERTIES OF EVA-BASED BLENDS( )
AT 72.5% FILLER LOADING
__
S Bulk
Average Vi~(4) Den- Vi~()
Ex. Fill~r(2)Yæticle E~ate RX~ Rate(5) _sity(6) Water
No~ No.size(3) Ratin~ 68-74F 90-95F g/ml. Level
(Microns)
36 1 2.5 112Q,000 60,000 1.02 Dry
37 2 3.4 1~120,000 13,300 0.98 Dry
38 3 5~0 1~80,0001263 0.95 -- (g)
39 4 14.0 3~2 1180 29 0.92 Mod.Wet
8.4 3706032 0.94 ~- (9)
41 6 6.0 240,000286 0.97 Dry
42 7 5.5 1~2 48,000 1560 0.97 Damp
C~17 8ca. 20 3~2 122 -- (8) 0.89 Mod.Wet
C-18 9ca. 26 53 -- (8) 0.82 Wet
43 10 5~4 1~4800 2400 0.93 Damp-Dry
~4 11 12.0 1~1~0,000 10,000 1.~2 -- (g)
(l)All blends i.n this table contain:
~a) EVA ~1 = 16.2~; 25~ VAc; 75~ ethylene; 2 ~II
(b) EV~ ~2 - 4~; 7.5% VAc; 92.5~ ethylene; 1.2 MT
(c) "Circosol" 4240 - 7.3~ naphthenic proces-
sing oil available from Sun Petrole~n Product~
Company. The composition for the oil as given
by the supplier is 39~ naph~henlc carbon,
40~ paraffinic carbon, and 21~ aromatic carbon.
Viscosity at 100~ is 2525 SUS. Speclfic
gravity i~ 0.9490.
(d~ Filler = 7205~
t )Fillers are described in Table XIII-
( )Typical values rom suppliers' charts or graphs.
These are not speci~ications and thus may v-ary
moderately from values given.
53
TAB~E ~XIV ~continued)
1 )For details of rating system, see Table ~V. Rating
of 1 is very smooth and "best"; 5 is vexy rough and
"worst."
( )Pour Rate is given ~ grams per 10 min. High values
are best. See "Descrlp~ion o~ Pour ~ate Test" balow.
(~Bulk density was measuxed by filling a 500-ml
gradua~ed cylinder tG the 500-ml mark. Filling was
accomplished by slow, careful pouring of ~he pellets
in~o th cylinder, without vibration or tamping.
Weight of pellets was measured in grams. Data were
calculated in gr~ms/ml.
(7)Visual wa~er level: As described in more detail
under "5ample Pxeparation," cooled s~rands ex the
water bath are blown with an air s~ream to remove
water ~ fore the strands are chopped. The pellets
from the Cumberland strand cu~ter are examined care-
fully or the presence of water~ The ratings as used
in Table XIV are:
Dry: The pellets are dry to the touch and will
not deposit water on a paper towe1.
Damp: Pellets are not ~uite dry to the ~ouch and
deposit only traces of water on a paper
towel.
Moderately Wet: Pellets feel wet and a few
water droplets will transfer readily to
the hands or to a paper towel.
Wet: Pellets contain much free water, some of
which can be seen with the naked eye. Water
transfers in drople~ form ~rom a handful
onto the ha~ds or forms wet patches on a
pape~ towel.
(8~Not tested; samples would surely block.
(9)~o observations made.
53
~4
when a coarse f iller is used ~ the pellets carry much
free water, which we~s the hands, blotting paper, etc.
(see also Tal:le XIVJ footno~e 7) .
54
TABLE X~.
RATING OF EXTP~UDATE STRAND PROPERTI}~S
1 = sest - No roughness discernible to naked eye
or to ~he touch on close examination.
2 - ~ ~ Slight roughness discernible to naked
e~e on close examination. Strands feel
smooth to touch~-but .not so smooth as
for a ~1 xating.
3 = Fair ~ Casual visual examination from close
distant-e shows slight pock holes or
ridges on extruded strands. A casual
observer would readily classify strands
as being rough to the touch.
4 = Poox = Strand xoughness is readily apparent
to all observers at arms ' leng~h.
Strands are def initely rough to the
touch .
5 3 Ver~h - Stxand roughness is severe and is
_.
easily detectable at a distance of
5 ~o 10 feet from the sample. l?rom a
close distance, the sample has siæable
ridges,and pock marks. The strand
looks and feels much like a very
coarse rat-tail file.
3~
~ 2~
Bulk Density: Rough strands cut into pellets
ob~iously produce rough pelle~s which require substan-
tial space in a container. Thus~ the bulk density value
for smooth pellets mad~ from fine fillér is substantially
higher t~.an that measured when the same procedure is
used with rough pellet~. For a valid comparison, it is
e~ential that the pellets being compared have the same
specific gravltyO I~ is ~or this reason that most of
oux data are presented at a unifoxm 72.5~ filler loading.
Pour Rating: When a bulk flow or pour rating
test is conducted on pellets made containing fine
particle size filler~ the smooth pellets flow instantly
from the ~est vessel. ~y contras~, as the pelle~ rough-
ness is increased, the pour rate falls sharply, ~ventu-
lS ally reaching a "no-flow" condition for "Control"
pellets made usin~ the coarse-grade "LC" filler. For
kest details, see "Description of Pour Rate Test," given
below.
Descrip~ion of Pour Rate Test:
A key property of substantial importance for a
bulk-shipped pelletized product is ~he ability of the
blend to be emptied ~uickly and completely from a rail
car. During rail car shipment, a series of events
occur--all o which magnify the tendency of the contents
o the rail car to "bridge" (interlock) sa that it may
become difficult to unload quickly, without special
labor-intensive pxocedures:
JTime alone favors tendency to "bridge"--
particularly by de~orming and interlacing of rough.
pellets.
-Pressureenhances tendency to defor~ and
interlock.
-High loading temperatures will sof~en
thermoplastic pell~ts, khus increasing the tendency
of the lading to def2rm and to bridge.
-Vibrationduring shipmen~ will acc2lera~
the tend~ncy of the lading to oompact, interlock, and
"bxidg~." 56
5~7
57
As a full rail car is an impractical means to
test the relative ease of handling, unloadin~, or
storing of pellets which are subject to "bridging,"
a small-scale, quick ~est is required. A test which
will do this has been devised. In brief, it consists
of placing a known weight of pellets to be tested into
a standardi2ed container at a predetermined temperature,
applying substantial pressure for a short ~ime period,
releasing the. pressure, and determining the rate of
discharge of the pellets when the can is inverted.
Temperature of pellets can of course be adjusted to
match precisely the conditions under which a rail car
will be loaded~ By applying very high pressure for a
short time, th~ compacting tendency of a long, slow
rail car shipmen~ can be simulated.
The s~eps in carrying out the laboratory~scale
block resistance test are:
1. Weigh 200 ~ 1 gram of pellets into a
stand~rd 1/2 pint paintcan. (Inside diameter - 2.8 in.;
height - 2.9 in.) The pellet temperature should be
regulated in advance to a desired value hy means of
storage or an adequate time period in a laboratory
oven. One hour preheating on a tray should suffice.
2~ Quickly place 2 kg standard~type
laborator~ weight (diameter = 2.6 in.) atop the pellet
charge. This ac~s as a pressure distributor and
transmitter-- any other similar incompressible object with a
diameter sligh~ly smaller than the paint can might be
used ins~ead.
3. Place the can and the pressure transmittin
weight in~o a standard-type laboratory press.
4 ~ Apply 4, OOQ pounds o force for 15 minutes
(This is approximately 650 psi, far higher than will be
encoun~ered under routine storage conditions.) .~s ~he
blends are compressible, adjust the applied load to
4,000 psi at 3-minu~e intervals.
57
$~ 7~
58
5. Release the pressure; remove the can;
remove the weigh~, and gentl~ but rapidly lnvert
the ca~ onto a wide-mesh (1~2 X 1/2 inch or larger)
screen.
6. Using a stopwatch, measure the time
requlred to empty the container~-or, alternately, fo~
blends with a poox flow rate, measure the amoun~ of
pellets which fall from the con~ainer in exactly 10
minutes.
7. For quick and easy comparison purposes,
cal~ulate the flow rate in grams/6.2 sq. in./min.
8. If desired, then convert the ~low rate
to any desired system of units to simulate ~he exit
opening from a ~ommercial storage system.
In practice, it may be desirable, depending
upon the type, size, and na~ure of the pelletized
compound, to use a higher or lower pressure, consist-
ently, ~o a~tain comparative results. FGr example,
where the pelle~s are soft and are severely ~istorted
or compacted by use of a 4,000-pound pressure loading,
it may be desirable to sharply reduce the pressuxe
applied. Similarly, di~ferently sized containers may
also be desirable where a closer-to~full-scale trial is
o~ interest.
During our tests, the use o 4,000-pound
pressure proved a good compromise in that very smooth
pellets would not block and would pour from the
container in less than one second. (Here, ~or conven-
ience, we used a value of one second for calculating
purposes.) Very rough blends would not flow at all--or
might dischaxge 5 to 20 grams at the s~art of the
maxi~um 10-minute test perlod allowed, and then s~op
flowi~.
Note that the pellets shcwn in Compaxatlve
ExampleQ C-17 and C-18 of Table ~IV are OL relatively low
quali~y by all of the ratings described above. Visually,
the strands were rated at 3.5 and 5,
58
`7~
. 59
respectively-~ or poor to very rough on the scale shown
in Table XV. The pour xate values are ver~ low--and
correspond on an industriaL scale to sampies which r~ill
barely flow from a rail car at am~ient conditions and
may not flow at all at temperatures of 95~F. or over.
The fre~hly cu~, rough, undried pellets hold large
amounts o water, which, under commercial conditions,
will require large equipment and high energy input to
at~ain significant tonnase out-put of a dry product.
A wet product i5 highly undesirable because: (1)
Wet pellets will reeze into a monolith during
wintertime rail shipment. (2) ~et pelle~s are notorious
causes of problems upon extrusion or injection molding,
and can cause personal injury or equipmen~ damage, plus
a poor-quality product. Finally, because pellets are
rou~h, they do not "pack" well-which will require a
relatively large~volume shipping container to package
a fixed weight of goods.
Examples 36,37, 38, 41, 42, a~d 43 ~how the dramatic
and unexpec~ed improvements at~ainable when the rela-
ti.vely coarse fillers used in Table XIV Comparative
Examples C-].7 ox C~ re rep aced with fine fillexs.
By reducing the average particle size from 20-26 microns
to about 2-6 microns, ~he following proper~ies improve:
-The extrudate roughness rating i5 in the
range o 2 or better.
-Freshly cut pellets are dry or nearly so.
-Bulk density values have risen by a
significant a~ount.
-Most important, pou_ rates have risen to
rates which are far higher than those seen for blends
C-17 and C-18.
As might be expected, when filler particles
of an intermedlate size are selected, blend properties
tend ~o be mldrange; that is, Detween "bes~" and
"poorestl' val~es, for all properties. Behavior of this
type is qhown by Xxamples 39 and 40.
59
" ~S~7~7
Example 44, which was made using barytes as a
filler in place of the ~9 ~hiting used in other exa~ples,
shows properties which are signi'icantly better than
those for Examples 39 and 40. This occurs because whiti~g
S has a specific gravity value of about 2.7, while barytes
has a value of about 4.5. ~s a result, at a concen~ra-
tion of 72.5~ of filler by weight, the volume~ric fillex
level i~ far less for the barytes-containing blend:
Whi~ing slend - 52% filler by vol~me.
Barytes slend - 36% filler by volume.
Thus~ possi~le adverse effec~s which coarser fillers will
induce will be far lessened for barytes-filled blends
because surface effect~ are related to volume percentage
o~ the solids in ~he blend, rather than to a weigh~ per~
15 centage .
E
-
The benefits described above which accrue when
the type of filler is changed from a coarse type to a
~.iner grade also occur with ethylene-based resins other
20 than those which are modified with vinyl acetate as a
comonomer. Table ~I shows the changes which occur when
changin~ from coarse to fine fillers for blends which
contain 72.5~ of filler and 7.3~ of a process oil, plus
a copolymer other than an E~A copolymer. The ethylene/
25 ethyl acrylate blends o~ Comparative Example 19 and
Example 45 are identical in all respects, with the sole
exception of the filler particle size employed. Also,
the ethylene/isobutyl acrylate co~olymer blends of
Comparative Example 20 and Example 46 ar~ identical i~
30 all respects, wi~h the sole exception of the filler
particle size. Finally, a third set of blends was al50
prepared. The ethylene/methyl me~hacrylate copolymer
blends of Comparative Example 21 and Example 47 are alike
in all respects, with the sole exception of the filler
35 particle size. In all three of these comparative cases,
based on non-E~A ethylene copolymers, the same effects
are noted
61
-Fine f iller produces a smooth ex~rudate
strand .
-Fine filler produces pellets which pour
freely even after standirlg under load.
-The bulk density value is higher when a
fine filler is used.
-Smooth pellets made using a finely
divided filler hold ~ery lit~le water.
61
~2 ~ 7~ ~
TABLE ~
~FFECTS OF FILLER PARTICLE SIZE
ON PROPERTIES OF E~HYLENE COPOL~MER
BLXNDS AT 72.5% FILLER( )
Copoly- Visual Pour Bulk Visual
Ex. mer~2) ~iller(3)Xxtrudate Rate Density Water
No. No. ~ Ratin~__ gO-95F (~/ml) 1evel
, . .. _ _ ~
C-l9 ACoarse 4~ 22 (4j 0.85 Wet
A Fine 1~ 120,000 0.99 ~ry
10 C-20 ~Coaxse 5 66 (4j 0.~3 Wet
46 B Fin~ 2 120,0Q0 0.99 Dry
C-21 CCoar~e 4 15 (4) 0.86 Wet
47 C Fine 1~ 120,000 1.0 Dry
(1)A11 blends contain~
Copolymer = 20.2%
"Circosol" 4240 = 7.3%
Fillex = 72.5~
~2)Copolymer numbers are:
(A) Ethylene/ethyl acrylate copolymer, grade
DP~A 6182~T, obtained from Union Caxbide
Corporation, con~ains about 15~ ethyl
acrylate, about 85~ e~hylene, and has a
melt index of about 1.5.
(3) Ethylene/isobutyl acrylate copolymer, 20%
isobutyl acrylate, 80~ ethylene, 2.5 MI.
~C) Ethylene/methyl methacrylate copolymer,
18% methyl methacrylate, 82% ethylene,
2.2 MI.
( )Coarse filler i5 FillPr ~8, Table ~III.
Fine filler is Filler ~1, Table ~III.
(4)Coarse filler samples ~ill not flow when pour tested
at 90F; hence, all test data for coarse filler only
were developed at the much~more-favorable 68-74~F
ambient ç~ndition.
62
~ 63 ~57~
le 22
The beneficial effec~s of using a ~inely
divided filler are not limited to blends which contain
72.5~ filler. Table XVII shows the results secured
when blends broadly similar to those of Table XIV are
compounded using only 65~ filler. When pxoperties of
the blend made for Comparative ~xample C-22 are
compared to tho~e of Exa~ples 48 and 49, it is evident
that the degree of improvement ls strongly related ~o
the par~icle size of the .selected fillex.
24
The preceding data are for blends made with
ethylene copolymers which contain substantial amounts
of comonomer. When the comonomer content is in the
18-28~ range, the copolymers tend to be soft, and flow
readily. At ranges from lS~ comonomer and below, the
polymers tend to be ~ar stiffer. To determine whether
the benefits noted earlier wh.ich accrue from the use
of fine fillers also apply for blen~s made with sti~fer
~0 resins, additional blends were made and their charac-
teristics de~ermined as su.~mari~ed i~ ~ables XVIII and XIX~
All blends were compounded in a laboratory-
scale Banbury Mixer for conYenience, as previously
de~cribed, and were then processed into sheet for~ in
a conven~ional two-roll mill. To mak~ test plaques or
sheets, the desired amount o~ blend would be weighed,
placed in a laboratory-scale heated press, and pressed
(between smooth release sheets of Teflon~-fluorocarbon
resin~ in a die of appropriate thic.~ness. For convenience
the present die had an opening or 6" X 6'~, was cut from
shee~ stock of 58 or 65 mils of thickness, depending
on blend density, and was charged in most instances with
63 grams o~ resin blend. This corresponds to 5 lbs.~yd.2
a commonly used sheet weight for automo~ive carp~t use.
A typical cycl was:
63
64 ~ 5t7;~
TABLE XVII
EFFECTS OF FILI,ER PARTICLE SIZE ON
PROPERTIES OF EVA-BASED BLENDS (1)
AT 65% FII,LER
. . . . ~
Visual Pour Bulk Visual
Ex. Filler~) Filler (3) Extrudate Ra~e Densi~y Water
No. No. Type_ Rati~ 90-35F /ml. Level
C-~2 8Coarse ~1250 0.83 Wet
4~ 1Very 1~120, 000 0 . 91 Dry
1 0 Fine
49 6~ine 2~40,000 0.89 Dry
~) All blends contain:
a) EVA ~1 = 25 . 0%
lS b) EVA ~2 = 3 . 5%
c) "Circosol" 4240 - 6 . 5
d) Filler = 65 O 0~
~2) (3)De~ails are given in Table XIII.
64
` . 65 ~ S7~
TABLE XVIII
EF~ECTS OF FINE FILLER ON THE
PROPERTIES OF B~ DS B~5~D Oi~, EVA HAVING I,OW
VI~rYL ACETATE COMONOMER CONTENT
Filler Visual Pour l~ulk Visual
No. & Extrudate Rate Density Water
Ex. ( ) ~ ~ 90-95F g/ml Level
C -23 8-Coarse "-32200 0 . 70 Wet
l-Very Fine1-2105, 000 0 . 70 Damp
10 C-24 8-Coarse 31720 0 . 74 Wet
51 1-Very Fine 2120, 00Q 0 . 80 Damp
52 lwVery Fine 2 5~ / 800 0 . 81 Dry
53 1-Vexy Fine 2610 0 . 78 Dry
15 ( ) Compositions and Blend proper~ies are given in
Table XIX.
( )Fille.rs are described in Table XIII.
3S 65
7'~
66
TABLE XIX
COMPOSITION AN3 PHYSICAL PROP~RTIES
OF TABLE XVIII BLENDS AND
SELECTED BLENDS OF TABLE XIV
EXAMPLE
C-23 50 ~ 24 51 52 53 C~17 36
_. _
Ingred~ents~
EV~ $1 ~ ~ -- 16.2 1~.2
EU~ ~2 40 40 ~ 28.5 -~ 4.0 4.0
10 ~ #3 ~ .5 ~ __
EV~ #g ~ __ 40 40 _ _~
"Circosol"
~240 5 ~ 5 5 6.5 6.5 7.3 7.3
Filler 55 55 55 55 65 65 72.5 72.5
Pi~ler No. ~ 1 ~ 1 1 1 8
Filler
Type C~ar æ Very Ccarse ~ry Very Very Co~rse Very
Fine F me Fine Fine Fine
Physical
~0 ~:
M~lt
In~ex(2) 1.231.06 ~.31 2.08 l.ll 0.73 3.09 1.64
Sp Gr o~
~1~ 1.461~47 1.47 1.46 1.66 1065 1.83 1~83
Tensile 5trength(3)
PSI 1020 1130 760 730 1130 1050 690 880
kPa 7030 7790 5240 5030 7790 7240 4760 6070
Elongation,
~(3) 30 40 67 49 26 30 34 46
30 Strip Thi~r.ess,
~15 75 7S 72 73 65 67 59 60
mm 1.90 10~ 1.82 1.85 1.67 1~70 1.50 1.52
~tiff~ess o~ Strip,(4)
g 260 260 15~ 150 200 150 70 6
35 Pour Rate
90-95F 2200 105,0001720 120,G00 54,800 610 122(5) 60,000
66
` 67 ~ '7~
(Footnotes for Table XIX)
(1) EVA characteristic5
~1: 25~ vinyl acetate, 75% ethylene, MI = 2.0
!'2: 7.5~ vinyl acetate, 92.5% ethylene, MI = 1.2
~3: 9.5~ vinyl ace~ate, 90.5~ ethylene t MI = 0.
~4: 12~ vinyl aceta~e, 88% ethylene, MI = 2.5
Fillers are described in Table XIII.
( j De~ermin~d by ASTM Method D 1238 at 190C.
(3) Tensile strength and elongation measurements made
on Instron Tes~er using AST~ ~ethod D 1708 a~ cross-
head speed of 2 in. (5.1 cm. )/min. Samples are
0u876 in (2.23 cm.) X 0.187 in (0.47 cm.) in size,
at strip thickness shown in table.
( ) Stifness of strip measured by placing a l in. X
6 in. (2.54 cm. X 15.2 cm.) strip on a platform
scale and measuring the force required to make the
ends of the test strip meet at room temperature.
(S) ~etermined at 68-74F--not determined at 90~95F,
as blocking o~ the sample is predictabl~.
67
`: 68 ~ Z~
(1) Place a Teflon3 shee~ on lowex press
platen or on top of a smooth ste~l baseplate if the
platen is not truly smoo~h~
(2) Place ~n 8" X 10" die plate t6" X 6"
5 openiIlg) atop the Tef lon~ sheet .
(3) Pu~ 63 g. of resin in the cavity. (1-2
grams surplus may be needed as some blend may ooze out
duxing pres 5 ing~ .
(4) Place a Teflon~ fluorocarbon sheet atop
10 the resin. Add a smooth steel upper plate if th platen
is nol: truly smoo~h.
t5) Heat the press to 175C.
(6) When the press reaches 175C., slowly
pump the press cl4sed ~o a total pxessure of abou~
12, 500 pounds ~150 psi, approximately) .
17) After 2 mirlutes, raise tAe ram pressure
to 50 , 000 pounds (~00 psi , approximately), and hold the
pressure and temperature constant or about 1 minute.
(8) Shut off heat and cool press to ambient
20 t:emperature with ram in closed posi~ioI10
(9) Release pressure, remove qample, a~d cut
ko appropriate shape for further testing.
tlO~ Age ~amples overnight a~ 50~i RH and 72~.
3S
68
69
In evalua~ing highly filled blends, grea~
care and good technique must be used in making all
samples, as surface imperfections will cause ~ide
variations in measurements o~ tensile strength and
elongation.
Blends of C-23 and Example 50 are identical
witn th~ exception of fineness of filler. Both are
based on a copolymer which oontalns only 7.5~ vinyl
~cetate comonomex, and thus are quite stlff and hard.
By contrast, E~A #1 with 25% vinyl ace~ate con~ent,
used as the principal resin in the blends of Table XIV,
is flexible and will produce flexible blends as seen
in Table XX.
TASLE XX
stif~neS9~1) Hardness(2)
EVA #1 20.7 36
EVA ~2 96.5 44
(l)MPa, method of ASTM D 747; psi values
are 3,000 & 14,000 respectively.
( )Shore D hardness, ASTM D ~706.
Examination o~ Table XV~II shows once again that the use
of a finely divided ~iller yields blends wltich will be
smcother to the eye and to the touch and ~hus will tend
to hold less water and to have a far superior flow
rate as measured by the pour rate tes~.
Examples 52 and 53 illus~rate blend~ at 65~
filler loadin~, between the earlier shown 55% and 72.5%
filler contents. Since a ~ine filler was used, once
again the pellets a~ained were smoo~h and dry. The
pour ratlng for Example 52 is excell~nt~ that for
Example 53 is marginal. Xt is believed that the
di~ferences are due to use of copolymers having
3S different ~inyl ac ta~e contents. The diffexences might
also indicate ~hat the pour rate test t although a useul
screening t~st t may not be ~o precise as might be desired.
Repetitive tests are desirable 7 n all cases to be certain
69
~ ~57 ~
tha~ error is no~ introduced in the long chain:
weighing ~ premixing - Banbury blending - extrusion -
chopping - and final tes~ing of pellets.
Discussion~ to this point have stressed only
the effects of fine filler on physical ex~rudate proper-
ties such as smoothness, tendency to hold water, relative
pour rate~, e~c. Those who wish to secure t~ese benefits
mu~t, of course, plan to investigate o~her, unrelated
changes to the properties of blends which might be
caused by changing the type of filler. As a suide to
compounders,Table XIX shows for several pairs of blends
from Tables XIV and ~ II th~ types of changes which may be
expected in o~her properties of interest. Generally,
these-changes are relatively small and are beneficial.
~a) ~elt Index - In all cases r use of a finer
fill2r decreased the melt index of the blend. Thus,
the use of finer filler increases blend ~îscosity.
However, the changes which occur are relatively small
and will probably be acceptable for most end user5~
In the case of Examples 52 and 53, the melt
index change noted reflects the lower melt index for
EVA ~3, vs. ~hat for EVA #2.
(b) Blend Specific Gravity - This property
is a~fected only by filler loading--no~ by the particle
~ize of ~iller or change in type of EVA resin selected.
(c) Tensile Strength and Elongation - In most
cases, use of a finer filler will enhance these proper-
ties by lO to 20%, although this did not occux for
Example 51 ~s. C-24. This could reflect lack o
sufficient mixing for sample Example 51, or could
reflect an error during the tensile test procedure. In
any event, the bulk of our experience indicates that it
is desirabl~ to use a fine ~iller where optimum tensile
strength and elongation are needed. Con~ersely, such
minor changes are probably not ~ommercially impor~ant
to ~os~ us~xs.
c 7 1
~ d) S~i~fness and Strip ~hickness - ~11 test
strips ~nade were based on constan~ weigh~ per unit
area, rather ~han constant volume per unit area. Thus,
all comparisc)ns presented mus~ be judged on a pair
5 basls. When this is done, it is evidPnt tha~ change
o:E ~iller par~icle size is far less important than is
filler amoun~ F~lr~her, choice of resin ls an importank
variable, as s~own by comE: arison o~ Example S2 with
Example 53-~high r V~c level results in a less stiff
10 blend, despite he use of a lewer mel~ ~ ndex copolymer.
(e) Pour Rate - The significan~ irnprov man~
produced by u~e of finer filler has been discu~sed in
detail abo~e . The comparisc: ns giY@n abo~re pro~7ide
strong reasc~ns for a ::ompounder ~o employ an ul~rafine
15 fill2r--but a change of ~his type is of necessity
accc~anied by adverse ~f fec~s . ~he amount of energy
input needed to make finer and finex filler grade is
a significarlt cost item~ In addi~ion, grinding and
classi~iciation e~Euipment output falls as finer par~icle
~o sizes are produced, and the ultimate customer must
o~ course bear the inves~ment burden required. 'Xhus,
or every product the compaunder mus~ balance the
co~ts of a ~iner ~iller Ye~sus the benefits that will
accrue. Therefore, the "best" chsice of filler fine-
25 ness must ~rary from user to user from applica~ion toapplica~ion.
This application is a division of copending
application Serial No. 339 920, filed 1979 November 15.
3~
