Note: Descriptions are shown in the official language in which they were submitted.
- 1-
, 1~9~
SINGLE PACKAGE ADDITIVE FOR THERMOPLASTIC FORMULATION
.
This invention relates to a process for preparing
a friable composition from paraffinic hydrocarbon waxes,
; calcium hydroxide and certain fatty acids, or calcium salts
of fatty acid, which are solid, glasslike, and remain friable
under ambient conditions. These compositions contain a full
~; 5 range of thermoplastic formulation ingredients, including
!,' stabilizers. More specifically, this invention relates to
compositions which, when placed in discrete particles, have
a low tendency to fuse or coalesce compared to paraffinic
hydrocarbon waxes and which are capable of being used as a
; 10 single additive for extrusion aids in thermoplastic formula-
tions. Such formulations become fluidized under elevated
temperatures on the order of 90C or higher.
Thermoplastic extrusion formulations such as those
containing polyvinyl chloride, commonly include paraffinic
hydrocarbon waxes and calcium salts of some fatty acids,
such as calcium stearate, as extrusion aids. These extrusion
formulations are generally fed to an extruder as a mixture
of particulate solids. It is desirable that any additives
~i to the formulations, including the extrusion aids, be in a
~i 20 discrete, solid particulate form capable of being handled as
solids. Unfortunately, the most economically satisfactory
materials are also sticky or mushy.
This problem was partially solved in the prior art.
U.S. Patents 3,883,362; 3,883,363; 3,979,345 and 3,986,995
~, 25 teach a method for producing a friable composition suitable
. . .
for use as an extrusion aid in polymeric extrusion formula-
tions by mixing a paraffinic hydrocarbon wax with calcium
hydroxide and a fatty acid, or a calcium salt of a fatty acid,
~; then heating to a temperature of at least 150C and thereafter;~ 30 cooling to recover a solid, glasslike, friable composition.
These processes were a great advance in the art in that they
allowed the use of mushy, low cost, paraffinic waxes instead
of the more expensive, high purity waxes. Both types of
wax produce excellent results when used in extrusion for-
mulations, but low cost paraffinic waxes were difficult to
handle. The prior art thus overcame a major objection in
,: , 7
.
- 2 ~ ~
allowing these materials to be handled in a solid, discrete
free-flowing 'orm with low tendency to agglomerate.
In these references, it is taught that it is
possible to incorporate other additives into the compositions
when they are employed as extrusion aids or lubricants. These
references state that other processing aids such as poly-
ethylene waxes or acrylate polymers may be included. Also
pigments such as titanium dioxide, fillers and reinforcing
materials can be included.
However, these materials did not include stabilizers,
thus preventing the formation of a single package for friable
composition additives for thermoplastic extrusions. Stabili-
zers, when incorporated using these processes prevented the
product from attaining a friable form, leaving them soft,
sticky and mushy instead.
It would therefore be of great benefit to provide
a method for obtaining a single package of additives in
friable, free-flowing form for thermoplastic extrusions.
The package should contain various waxes, pigments, fillers,
, 20 reinforcers and stabilizers, the sum of ingredients producing
a finished product.
~i It istherefore an object of the instant invention
; to provide a single package, friable composition, free-flowing
additives for thermoplastic extrusion. Other object will
become apparent to those skilled in this art as the descrip-
tion proceeds.
It has now been discovered according to the instant
invention that a single package, free-flowing, friable compo-
sition for addition to thermoplastic formulations during
extrusion can be prepared by a process comprising mixing a
, paraffinic hydrocarbon wax with calcium hydroxide and a fatty
J acid or a calcium salt of a fatty acid while heating to a
temperature of at least 150C, and while at this temperature
inserting desired additive materials, including stabilizers
which are supported on polyvinyl chloride resins, and there-
after cooling to recover a solid, glasslike friable composi-
tion, said paraffinic hydrocarbon wax having a drop melting
i
1124929
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point or at least 43C and oil content of not greater than
50% by weight and a needle penetration value of 25C in the
range of 1 millimeter to 20 millimeters, said fatty acid
being a C16 to C24 aliphatic hydrocarbon, monocarboxylic
acid or mixtures thereof.
Stabilizers useful in the instant invention are
those normally used in stabilizing PVC resin formulations.
Representative examples of such stabilizers are
Interstab Chemicals Inc. ET-250
~rgus Chemical Corp ~RK 1900
~RX 1925
MARK 1928 *
r~RK 2115
Cincinnati Milacron
Chemicals, Inc. TM 181 *
TM 692
M~T Chemicals, Inc. T 170
T 175
Synthetic Products Co. Synpron 1034
; 15 Cardinal Chemical Co. CC 7710 ~
The stabilizers utilized in the instant invention
are effective in forming a single package additive for
thermoplastic formulation extrusions. Stabilizers as used
:~ in the prior art have not been effective in this application
because the product obtained is soft and mushy. Such pro-
~ ducts are effective lubricants but cannot be easily stored
s and handled in conventional equipment. Such stabilizers can
;;~ be used in the method of the instant invention when first
absorbed on PVC resins.
The composition of the instant invention may be
prepared by charging the calcium salt of a fatty acid or
calcium hydroxide and fatty acid and paraffinic hydrocarbon
wax to a heated vessel equipped with an agitator. The wax
can be melted before charging to the vessel. Small amounts
of water may be present as is known in the grease art.
` ~nder continued agitation, the ingredients are heated to at
least 150DC, preferably at least about 160C to about 165C.
During this heatup time, the wax initially becomes molten,
forming a continuous phase in which the calcium salt particles
~ ~r ~ ~~
4-
are dis~ersed. After assuming the continuous phase, a
su~se~uent increase in viscosity is noticed until the mass
reaches a homogeneous, paste-like consistency. As the
temperature continues to rise, the paste-like mass breaks
into separate phases; a low viscosity oil-like phase and a
heavier paste-like phase. The heavier paste-like phase
appears to then form soft bead-like masses and the low
viscosity oil-like phase disappears into these masses. As
the temperature continues to rise, the soft bead-like masses
fuse and coalesce into a homogeneous taffy-like material.
It is at this point that the final temperature of about
160C will be reached and the other additives necessary for
the package can be added with agitation. Heating may be
continued for a short period of time to insure completion of
the transformation, even to higher temperatures just short
of degradation temperature.
The hot mass, now containing fillers, pigments,
: and stabilizer is removed from the vessel and cooled to
ambient conditions, whereupon the composition becomes a
solid, glass-like friable material which can be ground or
otherwise reduced into a particulate form. The particles
; formed will substantially retain their discreteness and
` integrity. The composition is a solid at ambient conditions
:~ and can be easily fractured or chopped. However, it is more
convenient and somewhat easier to grind the composition
under cryogenic conditions. However accomplished, the
resultant particulate composition at ambient conditions can
be easily handled with conventional solids handling equipment.
The particulate composition, containing all additives
necessary for thermoplastic formulation extrusion, will
maintain its integrity upon standing or being stored.
It is emphasized at the outset that the composi-
tion prepared with the process of this invention is not a
mere physical blend wherein each component contributes its
individual properties without any interaction with each
other. Rather, the physical form of the composition is
unlike either of the individual components. The composition
is best characterized as being a glass-like, friable solid
--5--
at ambient conditions, resulting from a synergistic action
between the paraffinic wax and calcium salt of a fatty acid
or calcium hydroxide and a fatty acid. ~rom a physical
chemistry standpoint, it is not known what actually occurs
in forming the composition.
Broadly, the process of the invention comprises
mixing paraffinic hydrocarbon wax, calcium hydroxide and
certain fatty acids while heating the mixture to at least
about 150C, preferably at least 160C, adding desired
formula material and the specific stabilizer disclosed
herein, and thereafter cooling and recovering the solid,
glass-like friable composition.
The fatty acids which may be employed are the C16-
` C2~ aliphatic hydrocarbon monocarboxylic acids or mixtures
thereof. These acids are preferably satùrated. When mixtures
of the acids are used, they may contain up to about 15
weight percent of a C14 aliphatic hydrocarbon monocarboxylic
acid of the same saturation characteristics outlined above.
~; Illustrative of suitable acids are palmitic, stearic, oleic,
, 20 linoleic, eicosanic, behenic, tall oil fatty acid, hydro-
~ genated vegetable fatty acid, hydrogenated tallow fatty
i~ acid, distilled cottonseed fatty acid, and the like. Various
; commercial grades of suitable acids are available, some of
. which are listed in Fatty Acids and Their Industrial
.~
Applications by E. S. Patterson, 1968, at Page 7, Table 1-2
,~ (excluding high lauric). Tnese suitable commercial acids
are generally mixtures of the acids hereinbefore described
and may additionally have small amounts of certain impurities
depending on their method of manufacture.
The calcium hydroxide employed may be any commercial
grade material such as slaked lime or hydrated lime.
The suitable paraffinic hydrocarbon waxes are
generally derived from petroleum sources. These waxes con-
tain a variety of hydrocarbon structures, for example normal
paraffins, isoparaffins, cycloparaffins, small quantities of
polycyclo-paraffins and aromatics and other hydrocarbons and
may be in a purified form or may contain oils depending upon
their source and/or manner of recovery. The paraffinic
1124929
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hydrocarbon waxes which are particularly useful are those
having a drop melting point (ASTM D 127-63) of at least
110F, preferably at least 145F, an oil content (ASTL>~ D
72165T) of not greater than 50 weight percent, preferably
not greater than 20 weight percent, and a needle penetratlon
value at 77F (ASTM D 1321-65) in the range of 1 mm to 20
mm, preferably 1 mm to 10 mm.
More specifically, the process of the invention
may be carried out by charging the paraffinic hydrocarbon
wax, calcium hydroxide and fatty acid to a heated vessel
equipped with an agitator. The wax may be premelted before
being charged or it may be melted in the vessel. The fatty
acid may be handled likewise as appropriate. The calcium
hydroxide, being a solid, may be charged using any convenient
solids handling means such as an auger.
Representative examples of thermoplastic formula-
tions which contain these materials are polyvinylchloride
extrusion formulations.
Representative examples of additives currently
used in various thermoplastic formulations are set forth. It
is emphasized that these additives are by no means exhaustive
of those which can be utilized in the instant invention.
However, it is essential to note that the stabilizers in-
corporated herein must be first supported on PVC resins in
~ 25 order to obtain a friable product. Additives which can be
; incorporated into the friable compositions include paraffin. wax as an external lubricant, calcium stearate as an internal
lubricant, polyethylene as an external lubricant, titanium
dioxide as pigments, calcium carbonates as fillers and
impact modifiers, and stabilizers of choice.
Representative but non-exhaustive examples of
types of methods and examples of which are useful in the
instant invention are:
External/Internal Lubricants
Paraffin wax
Polyethylene wax
Oxidized polyethylene wax
High molecular weight esters
Metal salts (Calcium stearate)
9~:9
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;rncnts
Titanium Dioxide
Carbon Black
Fillers
Calcium Carbonate
Gypsum (Calcium sulfate)
. Talc
Silica
. Processing Aids
i' _
Methacrylate polymers
; Styrene copolymers
R -OC -CH2C~2 S(CH2)XCOR
RloccH2cH2 / 5 (CK2 ) CoR2
R OCcH2cH2-sn ~ S(CH2) COR2
`~ S (CH2 ) XCOR2
R~
M - S(CH2)XeOR2 C
: ~1 and M[S(CR2)x 0~ ~3
Rl _ M - S(CH2)XcOR
M = Sn, Sb
R = alkyl groups - Cl-C12
R = as before
X = as before
~124929
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The instant invention is more concretely described
with reference to the examples below wherein all parts and
percentages are by weight unless otherwise specified. The
examples are provided to illustrate the instant invention
and not to limit it.
In all experiments set forth below, wax having the
physical characteristics described was melted and lime was
slurried. The reaction was held at 80 to 90C. Stearic
acid was added and the reaction process was agitated for 30
minutes. Heat was increased until the reaction mixture
began to build up on the stir blade at about 160 to 165C.
Other ingredients were then added as listed. Examples 1
through 5 are comparative examples showing the use of some
commercially available stabilizers when not supported on PVC
resins prior to incorporation. Example 1 shows a tin sta-
bilizer alone as an additive. Example 2 shows a tin stabi-
lizer with a filler. Example 3 shows the use of another tin
stabilizer with filler and pigment. Example 4 shows use of
` a tin stabilizer with polyethylene, filler, and pigment.
Example 5 shows the use of antimony stabilizer. Examples 6
and 7 show the stabilizers of the present invention supported
on PVC resin to yield a single package, friable additive.
The same paraffinic wax was used in all examples.
Example 1
Using the general procedure described above, the
following materials were charged to the reactor.
Paraffin wax240g (Trademark of and
(Code 776)sold by Conoco Inc.)
Ca(O~)2 24.6g
Stearic acid150g
Tin Stabilizer100g (Trademark of and
(TM 387)sold by Cincinatti-
Milacron)
The ingredients were added in the order listed.
After the stabilizer was added to the product, the product
became pastelike. After cooling, the product assumed the
form of a soft, mushy material.
1*~92~
_9.
Example 2
The following ingredients were charged to the
reactor.
: Paraffin wax 240g
; Ca~OH)2 25.9g
Stearic acid 149g
,~ CaCO3 600g
Tin S~abilizer100g
(TM 387)
~ After the stabilizer was added, the product became
; 10sticky and remained so even after cooling to ambient condi-
, tions.
~ Example 3
"~,
The following materials were added in the order
~$ indicated.
Paraffinic wax270g
Ca(OH2) 25g
Stearic acid 150g
Polyethylene30g (AC-629-A, Trademark
of and sold by Allied
Chemical Co.)
Tio2 200g
CaCO3 6G0g
Tin Stabilizer80g (Mark 1928, Trademark
of and sold by Argus
Chemical Co.)
~pon addition of the final stabilizer, the product
became a sticky glue. Upon cooling the product attained a
paste-like, solid consistency. The product was not friable.
Example 4
The following materials were added in the order
set forth.
Paraffinic wax135g
Ca(OH)2 12.5g
Stearic acid 75g
Polyethylene
(AC-629-A) 15g
Tio2 100g
aCO3 300g
~in Stabilizer
(Mark 1928) 30g
1~2492g
--10--
Vpon addition of the final stabilizers, the
product became sticky and stringy. Mo friable composition
could be formed.
Example 5
The fOllowing materials were ad~e~ in the order
descrihed.
Paraffinic wax 270g
CatOH)2 25g
Stearic acid 150g
Polyethylene (~C-629-A) 30g
TiO2 200g
CaCO3 600g
Synpron 103480g (Antimony stabiliz~
trademark of and
sold by Synthetic
Products)
` 15 Immediately upon addition of the stabilizer, the
product became a sticky paste. The paste-like consistency
remained when cooled. The product was not friable.
Example 6
Paraffinic wax 11~2g1132g
Ca(OH)2 113g
Stearic acid 679g
Polyethylene (AC-629-A) 136g
i2 905g
CaCO3 4529g
Physical blend of1630g (Trademark of and
Tin Stabilizersold by Argus
(Mark 1925) andChemical Co.)
CONOCO 5385 PVC resin,
1:5 weight ratio,
respectively
3~ After completion of the reaction the product was
cooled to ambient temperature. The product formed a glass-
like, friable compound. When ground to discrete particles,
the compound remained friable.
1124929
., .
. .
~xample 7
Paraffinic wax 125g
Ca(OH)2 12.5g
~ Stearic acid 75g
; Polyethylene (AC-629A)15q
~ 5 TiO 100g
'. CaC03 SOOg
Physical blend of time
stabilizer (Cincinnati-
Milac~on TM-692) and
CO~OCO 5385 PVC resin
1:5 weight ratio
respectively 180g
;~
After completion of the reaction, the product
was cooled to ambient temperature. The product formed a
glass-like, friable compound. When ground to discrete
particles, the compound remained friable.
Upon addition of PVC with adsorbed stabilizer
the reaction products become homogeneous, taffy-like mat-
erials. Vpon cooling to ambient temperature (or somewhat
below for best results) the product was sufficiently hard
to ground to discrete particles. The particles remained
discrete and friable under ambient con~itions.
Stabilizers are supported on PVC resin simply by
blending the stabilizer with an amount of resin sufficient
to absorb and/or support the quantity o~ stabilizer used.
Normally the ratio of stabilizer to resin will range from
about 1 to 1 to about 1 to 100 respectively, but from about
1 to 4 to about 1 to 7 is preferred.
In the process of the instant invention, the
materials must be 'neated to at least 150C in order to
form friable compositions. However, temperatures of 160C
are preferred. The process can be carried out when the
fatty acid is mixed with a paraffinic hydrocarbon wax prior
to adding the calcium hydroxide. However, the calcium hy-
droxide is preferably mixed with a paraffinic hydrocarbon
wax prior to adding the fatty acid.
; . . 1~Z4929
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~'
The mole ratio of calcium hydroxide to fatty
acid ranges from about 0.5 to 1 respectively to about 1 to 1
respectively. However, the preferred range of mole ratios
is from about 0.55 to 1 to about 0.65 to 1 respectively.
The weight ratio of wax to calcium salt of the
;; fatty acid is normally in the range of fr~m ~hout 0.3 to 1
to about 2.5 to 1 respectively. However, the preLe;-red
weight ratio range of wax of fatty acid is from about 0.6
to 1 to about 1.7 to 1 respectively.
~araffinic hydrocarbon wax of the instant
invention should have a drop melting point of at least
43C but a drop melting point of about 60C is preferred.
These waxes should have an oil content of not greater than
50 weight percent by weight but an oil content of not greater
than 20 percent by weight is preferred. The needle pene-
~ tration value at 25C will fall in the range of from 1
millimiter (mm) to 20 millimeters but a needle penetration
value from 1 mm to 10 mm is preferred.
Likewise, the calcium salts which may be employed
are those derived from C16 to C24 aliphatic hydrocarbon
monocarboxylic acid and mixtures thereof. These acids can
be saturated or unsaturated. The mixtures of the acids are
used that can contain up to about 15 weight per~ent of the
C14 aliphatic hydrocarbon monocarboxylic acid of the same
saturation characteristics set forth. Illustrative but non-
exhaustive of suitable acids are palmitic, stearic, oleic
linoleic, eicosanic, behenic, tall oil fatty acid, hydrogen~
ated vegetable fatty acid, hydrogenated tallow fatty acid,
distilled cottonseed fatty acid, and the like. Suitable
commercial acids are generally mixtures of the acids described
and may additionally have small amounts of certain impurities
depending upon their methods of manufacture. Therefore,
mixtures of fatty acids can easily be employed.
In addition, the process utilizing the mixture of
fatty acids can contain up to about 15% by weight of a C14
aliphatic hydrocarbon monocarboxylic acid.
No one stabilizer need be used alone. Mixtures of
these stabilizers can also be used to form a frlable composi-
tion.
1~24929
-13--
While certain embodiments and details have been
;, shown for the purpose of illustrating this invention, it
will be apparent to those skilled in this art that various
changes and modifications may be made herein without departing
,. 5 from the spirit or scope of the invention.
, We claim:
