Single package additive for thermoplastic formulation

A friable composition single additive package for thermoplastic extrusions is provided in the instant invention. The friable composition can contain paraffin waxes, calcium stearate, various pigments, fillers, lubricants, and stabilizers.

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 
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 single additive for extrusion aids in thermoplastic 
formulations. Such formulations become fluidized under elevated 
temperatures on the order of 90.degree. C. 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 to the 
formulations, including the extrusion aids, be in a 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. Pat. Nos. 
3,883,362; 3,883,363; 3,979,345; and 3,986,995 teach a method for 
producing a friable composition suitable for use as an extrusion aid in 
polymeric extrusion formulations 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 150.degree. C. and 
thereafter 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 formulations, but low cost paraffinic waxes were difficult to 
handle. The prior art thus overcame a major objection in allowing these 
materials to be handled in a solid, discrete free-flowing form with low 
tendency to agglomerate. 
These four references are hereby incorporated by reference in their 
entirety. 
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 
polyethylene 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. Stabilizers, 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, reinforcers and stabilizers, the sum of ingredients 
producing a finished product. 
It is therefore an object of the instant invention to provide a single 
package, friable composition, free-flowing additives for thermoplastic 
extrusion. Other objects will become apparent to those skilled in this art 
as the description proceeds. 
It has now been discovered according to the instant invention that a single 
package, free-flowing, friable composition 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 
acid or a calcium salt of a fatty acid while heating to a temperature of 
at least 150.degree. C., and while at this temperature inserting desired 
additive materials, including stabilizers which are supported on polyvinyl 
chloride resins, and thereafter cooling to recover a solid, glasslike 
friable composition, said paraffinic hydrocarbon wax having a drop melting 
point of at least 43.degree. C. and oil content of not greater than 50% by 
weight and a needle penetration value of 25.degree. C. in the range of 1 
millimeter to 20 millimeters, said fatty acid being a C.sub.16 to C.sub.24 
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 
Argus Chemical Corp MARK 1900 
MARK 1925 
MARK 1928 
MARK 2115 
Cincinnati Milacron 
Chemicals, Inc. TM 181 
TM 692 
M & T Chemicals, Inc. T 170 
T 175 
Synthetic Products Co. 
Synpron 1034 
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 products 
are effective lubricants but cannot be easily stored 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. Under continued 
agitation, the ingredients are heated to at least 150.degree. C., 
preferably at least about 160.degree. C. to about 165.degree. C. During 
this heatup time, the wax initially becomes molten, forming a continuous 
phase in which the calcium salt particles are dispersed. After assuming 
the continuous phase, a subsequent 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 160.degree. C. 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 composition 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 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. From 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 150.degree. C., preferably at least 
160.degree. C., 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 C.sub.16 -C.sub.24 aliphatic 
hydrocarbon monocarboxylic acids or mixtures thereof. These acids are 
preferably saturated. When mixtures of the acids are used, they may 
contain up to about 15 weight percent of a C.sub.14 aliphatic hydrocarbon 
monocarboxylic acid of the same saturation characteristics outlined above. 
Illustrative of suitable acids are palmitic, stearic, oleic, linoleic, 
eicosanic, behenic, tall oil fatty acid, hydrogenated vegetable fatty 
acid, hydrogenated tallow fatty 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). These 
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 contain 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 hydrocarbon 
waxes which are particularly useful are those having a drop melting point 
(ASTM D 127-63) of at least 110.degree. F., preferably at least 
145.degree. F., an oil content (ASTM D 72165T) of not greater than 50 
weight percent, preferably not greater than 20 weight percent, and a 
needle penetration value at 77.degree. F. (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 formulations 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 
incorporated herein must be first supported on PVC resins in 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 additives and 
examples of those 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) 
Pigments 
Titanium Dioxide 
Carbon Black 
Fillers 
Calcium Carbonate 
Gypsum (Calcium sulfate) 
Talc 
Silica 
Processing Aids 
Methacrylate polymers 
Styrene copolymers 
##STR1## 
##STR2## 
##STR3## 
______________________________________ 
M = Sn, Sb 
R.sup.1 = alkyl groups C.sub.1 -C.sub. 12 
R.sup.2 = as before 
X = as before

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.degree. to 90.degree. C. 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.degree. to 
165.degree. C. 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 stabilizer alone as an additive. 
Example 2 shows a tin stabilizer 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 wax 240g (Trademark of and 
(Code 776) sold by Conoco Inc.) 
Ca(OH).sub.2 24.6g 
Stearic acid 150g 
Tin Stabilizer 100g (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. 
EXAMPLE 2 
The following ingredients were charged to the reactor. 
______________________________________ 
Paraffin wax 240g 
Ca(OH).sub.2 25.9g 
Stearic acid 149g 
CaCO.sub.3 600g 
Tin Stabilizer 100g 
(TM 387) 
______________________________________ 
After the stabilizer was added, the product became sticky and remained so 
even after cooling to ambient conditions. 
EXAMPLE 3 
The following materials were added in the order indicated. 
______________________________________ 
Paraffinic wax 270g 
Ca(OH.sub.2) 25g 
Stearic acid 150g 
Polyethylene 30g (AC-629-A, Trademark 
of and sold by Allied 
Chemical Co.) 
TiO.sub.2 200g 
CaCO.sub.3 600g 
Tin Stabilizer 80g (Mark 1928, Trademark 
of and sold by Argus 
Chemical Co.) 
______________________________________ 
Upon 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 wax 135g 
Ca(OH).sub.2 12.5g 
Stearic acid 75g 
Polyethylene 
(AC-629-A) 15g 
TiO.sub.2 100g 
CaCO.sub.3 300g 
Tin Stabilizer 
(Mark 1928) 30g 
______________________________________ 
Upon addition of the final stabilizers, the product became sticky and 
stringy. No friable composition could be formed. 
EXAMPLE 5 
The following materials were added in the order described. 
______________________________________ 
Paraffinic wax 270g 
Ca(OH).sub.2 25g 
Stearic acid 150g 
Polyethylene (AC-629-A) 
30g 
TiO.sub.2 200g 
CaCO.sub.3 600g 
Synpron 1034 80g (Antimony stabilizer 
trademark of and 
sold by Synthetic 
Products) 
______________________________________ 
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 1132g 
1132g 
Ca(OH).sub.2 113g 
Stearic acid 679g 
Polyethylene (AC-629-A) 
136g 
TiO.sub.2 905g 
CaCO.sub.3 4529g 
Physical blend of 1630g (Trademark of and 
Tin Stabilizer sold by Argus 
(Mark 1925) and Chemical Co.) 
CONOCO 5385 PVC resin, 
1:5 weight ratio, 
respectively 
______________________________________ 
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. 
EXAMPLE 7 
______________________________________ 
Paraffinic wax 125g 
Ca(OH).sub.2 12.5g 
Stearic acid 75g 
Polyethylene (AC-629A) 15g 
TiO.sub.2 100g 
CaCO.sub.3 500g 
Physical blend of tin 
stabilizer (Cincinnati- 
Milacron TM-692) and 
CONOCO 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 materials. Upon 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 conditions. 
Stabilizers are supported on PVC resin simply by blending the stabilizer 
with an amount of resin sufficient to absorb and/or support the quantity 
of 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 heated to at 
least 150.degree. C. in order to form friable compositions. However, 
temperatures of 160.degree. C. 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 hydroxide is 
preferably mixed with a paraffinic hydrocarbon wax prior to adding the 
fatty acid. 
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 from about 0.3 to 1 to about 2.5 to 1 respectively. However, 
the preferred weight ratio range of wax of fatty acid is from about 0.6 to 
1 to about 1.7 to 1 respectively. 
Paraffinic hydrocarbon wax of the instant invention should have a drop 
melting point of at least 43.degree. C. but a drop melting point of about 
60.degree. C. 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 penetration value at 
25.degree. C. will fall in the range of from 1 millimeter (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 
C.sub.16 to C.sub.24 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 
percent of the C.sub.14 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, hydrogenated 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 C.sub.14 aliphatic hydrocarbon 
monocarboxylic acid. 
No one stabilizer need be used alone. Mixtures of these stabilizers can 
also be used to form a friable composition. 
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 from the spirit or scope of the invention.