Liquid stabilizer systems and vinyl halide resin compositions containing same

Vinyl halide resin compositions that are characterized by excellent early color and color hold, excellent long term heat and light stability, and good processability contain a liquid stabilizer system that comprises PA0 A. 40% to 90% by weight of an organotin ethanol mercaptide having the structural formula ##STR1## WHEREIN EACH R represents an alkyl group having 1 to 8 carbon atoms, R' represents --SCH.sub.2 CH.sub.2 OH, --SCH.sub.2 COOR", or --SR", PA1 R" represents an alkyl group having 6 to 18 carbon atoms, PA1 a, b, m, and n each represents 1 or 2, PA1 X represents 0 or 1, PA1 When X is 0, m + n + b = 4, and PA1 When X is 1, m + n = 3 and a + b = 3; PA0 B. 10% to 60% by weight of a liquid alcohol component comprising a glycol having 2 to 10 carbon atoms; and PA0 C. 0.1% to 1% by weight of an alkyl acid phosphate.

This invention relates to liquid stabilizer systems for vinyl halide resin 
compositions and to resinous compositions stabilized therewith. More 
particularly, it relates to vinyl halide resin compositions that contain a 
stabilizer system comprising an organotin ethanol mercaptide, a liquid 
alcohol component comprising a glycol having 2 to 10 carbon atoms, and an 
alkyl acid phosphate. 
It is well known that vinyl halide resins undergo undesirable changes when 
they are exposed to heat and to light and that these changes lead to 
discoloration and to deterioration of the mechanical properties of the 
compositions. Since elevated temperatures are required for the processing 
of these resins and since the resins are exposed to light when they are 
subsequently used, it is necessary to incorporate in the vinyl halide 
resin compositions stabilizers that will inhibit or prevent their 
discoloration when they are exposed to heat and to light. 
Organotin compounds that contain sulfur have long been recognized as highly 
effective heat stabilizers for vinyl halide resin compositions. The 
stabilizing effectiveness of these compounds is generally directly related 
to their tin content and to a lesser extent to their sulfur content. The 
organotin compounds that have high tin and sulfur contents, however, have 
several disadvantages that have severely limited their use. These 
compounds, which are expensive relative to other available stabilizers, 
often impart a yellow cast and haze to vinyl halide resin compositions 
during the first few minutes of heating, and they cause the development 
during processing of a strong, unpleasant odor, which remains noticeable 
in the finished product. Many of these compounds are unstable and 
decompose quickly to form inactive compounds. In addition, the organotin 
compounds that have high tin and sulfur contents are often glassy, very 
viscous materials that are difficult to handle and to incorporate into 
resinous compositions. 
While the use of organotin compounds and mercaptoalcohols is known in the 
art, there has been no teaching of stabilizer systems derived from these 
materials that prevent the degradation of vinyl halide resins at elevated 
temperatures without imparting early color, cloudiness, or odor to them 
and that do not undergo decomposition on storage. 
In U.S. Pat. No. 3,063,963, Wooten et al. disclosed the use of combinations 
of organotin carboxylates of mono- or dicarboxylic acids with 
omega-mercapto acid esters or omega-mercaptoalcohols to improve the 
weathering resistance of polyvinyl chloride resins. There is no suggestion 
that early discoloration was lessened in the compositions that were 
disclosed. Combinations of organotin mercaptocarboxylic acid esters with 
mercaptocarboxylic acids and mercaptoalcohols were disclosed by Pollock in 
U.S. Pat. No. 3,507,827. 
Ramsden in U.S. Pat. No. 2,885,415 taught the use of organotin derivatives 
of mercaptoalcohols as stabilizers for chlorine-containing resins. These 
compounds, which have one of the formulas R.sub.3 Sn(SR'OH), R.sub.3 
Sn--S--R'O--SR.sub.3, and 
##STR2## 
wherein R and R' are hydrocarbon radicals, are viscous liquids or 
crystalline solids that are difficult to handle and to incorporate into 
resinous compositions and that tend to decompose on standing. 
It has now been found that stabilizer systems that impart excellent initial 
color and clarity and excellent long term heat and light stability to 
vinyl halide resin compositions result when an organotin ethanol 
mercaptide is combined with a liquid alcohol component that comprises a 
glycol and an alkyl acid phosphate. The resulting stabilizer systems are 
light colored, non-viscous liquids that are convenient to handle and that 
can be readily incorporated into resinous compositions. They are stable 
and can be stored for prolonged periods without losing their 
effectiveness. These stabilizer systems have the further advantage of 
substantially eliminating the development of objectionable odors during 
the processing of the resinous compositions as well as residual odors 
previously encountered in finished products that contain organotin 
mercaptide or organotin sulfide stabilizers. 
The first component of the liquid stabilizer systems of this invention is 
an organotin ethanol mercaptide having the structural formula 
##STR3## 
wherein each R represents an alkyl group having 1 to 8 carbon atoms; R' 
represents --SCH.sub.2 CH.sub.2 OH, --SCH.sub.2 COOR", or --SR"; R" 
represents an alkyl group having 6 to 18 carbon atoms; a, b, m, and n each 
represents 1 or 2; X represents 0 or 1; when X is 0, m + n + = 4; and when 
X is 1, m + n = 3 and a + b = 3. 
A preferred group of organotin ethanol mercaptides have the structural 
formula 
##STR4## 
wherein R, R", m, n, and b have the aforementioned significance, R.degree. 
represents --SCH.sub.2 COOR" or --SR", and m + n + b = 4. Illustrative of 
these compounds are monobutyltin mono (hexyl thioglycolate) di(ethanol 
mercaptide), monooctyltin mono(dodecyl thioglycolate) di(ethanol 
mercaptide), monomethyltin mono(octadecyl thioglycolate) di(ethanol 
mercaptide), monobutyltin mono (dodecyl mercaptide) di(ethanol 
mercaptide), monomethyltin mono (hexyl mercaptide) di(ethanol mercaptide), 
monobutyltin di(hexyl mercaptide) mono(ethanol mercaptide), monooctyltin 
di(hexyl thioglycolate) mono(ethanol mercaptide), monobutyltin di(isooctyl 
thioglycolate) mono(ethanol mercaptide), dimethyltin mono(isodecyl 
thioglycolate) mono(ethanol mercaptide), dihexyltin mono(octadecyl 
thioglycolate) mono(ethanol mercaptide), dioctyltin mono(octadecyl 
mercaptide) mono(ethanol mercaptide), and dimethyltin mono(hexyl 
mercaptide) mono(ethanol mercaptide). 
Another preferred group of organotin ethanol mercaptides have the 
structural formula 
##STR5## 
wherein R, R', R", a, b, m, and n have the aforementioned significance; a 
b = 3; and m + n = 3. Illustrative of these compounds are 
bis[monobutyltin di(ethanol mercaptide)]sulfide, bis[monooctyltin 
di(ethanol mercaptide)]sulfide, bis[dimethyltin mono(ethanol 
mercaptide)]sulfide, [dibutyltin mono(dodecyl mercaptide)] [dibutyltin 
mono(ethanol mercaptide)]sulfide, [dioctyltin mono(hexyl mercaptide)] 
[dioctyltin mono(ethanol mercaptide)]sulfide, [dimethyltin mono(octadecyl 
thioglycolate)] [dimethyltin mono(ethanol mercaptide)]sulfide, 
[monobutyltin di(octadecyl mercaptide)] [monobutyltin di(ethanol 
mercaptide)]sulfide, [monomethyltin di(2-ethylhexyl thioglycolate)] 
[monomethyltin di(ethanol mercaptide)]sulfide, and [monobutyltin 
di(dodecyl thioglycolate)] [dibutyltin mono(ethanol mercaptide)]sulfide. 
A single organotin ethanol mercaptide or a mixture of two or more of these 
compounds may be present in the liquid stabilizer systems. 
The organotin ethanol mercaptides can be prepared by any suitable 
procedure, for example, by heating an alkyltin compound, such as an 
alkylstannoic acid, an alkyltin oxide, or an alkyltin hydroxide, with a 
mercaptoethanol and a sulfur-containing compound, such as an alkyl 
mercaptan, an alkyl thioglycolate, and/or a sulfide, at a temperature 
between about 90.degree. C. and 130.degree. C. under subatmospheric 
pressure until the water evolved during the reaction has been removed from 
the reaction mixture. Because some of the compounds prepared in this way 
are unstable liquids that start to decompose to form inactive crystalline 
products on standing for several days at room temperature, the 
freshly-prepared organotin ethanol mercaptides are ordinarily dissolved in 
a solvent that contains the liquid alcohol component and the alkyl acid 
phosphate to form the stable liquid stabilizer systems of this invention. 
The liquid alcohol component in which the organotin ethanol mercaptide is 
dissolved comprises a glycol having 2 to 10 carbon atoms. Suitable glycols 
include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 
2-methyl-1,2-propanediol, 1,2- butanediol, 1,3-butanediol, 1,4-butanediol, 
3-methyl-1,2-butanediol, 1,4-pentanediol, 1,5-pentanediol, 
2-methyl-2,4-pentanediol (hexylene glycol), 2,2-dimethyl-1,5-pentanediol, 
2-ethyl-1,3-hexanediol, 1,7-heptanediol, and the like and mixtures 
thereof. A preferred glycol is 2-methyl-2,4-pentanediol (hexylene glycol). 
The liquid alcohol component may also contain one or more straight-chain or 
branched-chain alkanols having 4 to 18 carbon atoms. These include 
butanol, isobutanol, n-hexanol, 2-ethylhexanol, n-octanol, dodecanol, 
isotridecanol, n-octadecanol, isooctadecanol, and mixtures thereof. It may 
also contain a small amount of a polyhydric alcohol, such as glycerol or a 
water-insoluble trihydric or tetrahydric alcohol having a molecular weight 
of about 300 to 6000. The preferred polyhydric alcohols are polyethers 
formed by the reaction of propylene oxide with glycerol, 
trimethylolpropane, or pentaerythritol. 
Particularly good results have been obtained when the liquid alcohol 
component of the stabilizer system contained from 50% to 100% by weight of 
hexylene glycol and up to 50% by weight of one or more straight-chain 
and/or branched-chain monohydric alcohols having 8 to 15 carbon atoms. 
The liquid stabilizer systems also contain a small amount of an alkyl acid 
phosphate, which enhances their stability. It may be a monoalkyl acid 
phosphate, a dialkyl acid phosphate, or a mixture of mono- and dialkyl 
acid phosphates in which each alkyl group has from 1 to 10 carbon atoms, 
Examples of these alkyl acid phosphates include methyl acid phosphate, 
isopropyl acid phosphate, n-butyl acid phosphate, secondary isoamyl acid 
phosphate, hexyl acid phosphate, 2-ethylhexyl acid phosphate, n-decyl acid 
phosphate, diethyl acid phosphate, di-secondary isohexyl acid phosphate, 
di-n-octyl acid phosphate, ethyl 2-ethylhexyl acid phosphate, and isobutyl 
n-octyl acid phosphate. 
While a single alkyl acid phosphate can be used, in most cases it is 
preferred that a mixture that contains at least one monoalkyl acid 
phosphate and at least one dialkyl acid phosphate be used. Such mixtures 
of alkyl acid phosphates can be prepared, for example, by reacting about 
2.5 moles to 3.5 moles of one or more alcohols with one mole of phosphorus 
pentoxide. The alcohols that can be used in this reaction are primary, 
secondary, and tertiary alkanols that have from 1 to 10 carbon atoms. 
Stabilizer systems having exceptionally good shelf stability have resulted 
when the alkyl acid phosphate used in their preparation was the mixture of 
acid phosphates that resulted when 3 moles of methyl isobutyl carbinol 
(4-methylpentanol-2) was reacted with one mole of a phosphorus pentoxide. 
The term "secondary 4-methylpentyl acid phosphate" is used herein to 
identify this mixture of mono- and di-acid phosphates. 
As has been indicated, the liquid stabilizer systems can be prepared by 
dissolving freshly-prepared organotin ethanol mercaptides in a solvent 
that contains a liquid alcohol component and an alkyl acid phosphate. They 
are preferably prepared by carrying out the reaction between the organotin 
compound, mercaptoethanol, and sulfur containing compound to form the 
organotin ethanol mercaptide in the presence of all or part of the liquid 
alcohol component and adding to the resulting solution any remaining 
alcohol and the alkyl acid phosphate or by carrying out the reaction in 
the presence of both the alcohol component and the alkyl acid phosphate. 
The stabilizer systems of this invention are non-viscous, clear, 
light-colored liquids that have little or no tendency to decompose on 
standing and that are more effective as stabilizers for vinyl halide 
resins than the organotin ethanol mercaptides that they contain. These 
stabilizer systems contain from about 40% to 90% by weight of an organotin 
ethanol mercaptide, 10% to 60% by weight of the liquid alcohol component, 
and 0.1% to 1% by weight of the alkyl acid phosphate. They preferably 
contain 60% to 90% by weight of an organotin ethanol mercaptide, 10% to 
40% by weight of a liquid alcohol component that comprises hexylene 
glycol, and 0.2% to 0.6% by weight of secondary 4-methylpentyl acid 
phosphate. 
In addition to the aforementioned components, the liquid stabilizer systems 
of this invention may contain other heat and light stabilizers such as 
other organotin compounds, salts of barium, cadmium, and other polyvalent 
metals, and organic phosphites, antioxidants, lubricants, solvents, and 
other additives that are ordinarily employed in the production of 
stabilized vinyl halide resin compositions. 
Only a small amount of one of these liquid stabilizer systems need be 
incorporated into vinyl halide resin compositions to impart heat and light 
stability to them. As little as 0.2% of one of these stabilizer systems, 
based on the weight of the vinyl halide resin, will bring about an 
appreciable improvement in the heat stability of the compositions. Five 
percent or more of the stabilizer systems can be used, but these larger 
amounts generally do not provide further improvement in the properties of 
the resinous compositions and for this reason are not ordinarily used. In 
most cases, from 0.3% to 3% by weight, based on the weight of the vinyl 
halide resin of a liquid stabilizer system gives the most advantageous 
results. 
The stabilizer systems of this invention are of particular value in the 
stabilization of rigid polyvinyl chloride compositions, that is, 
compositions that are formulated to withstand temperatures of at least 
175.degree. C., for example, the pigmented compositions used in the 
production of pipe. The novel stabilizer systems can also be used in 
plasticized vinyl halide resin compositions of conventional formulation 
where high softening point is not a requisite. 
The vinyl halide resins that may be present in the stabilized resinous 
compositions include both vinyl halide homopolymers, such as polyvinyl 
chloride, polyvinyl bromine, and polyvinylidene chloride, and copolymers 
formed by the polymerization of a vinyl halide with up to about 30 percent 
of a comonomer, such as vinyl acetate, vinyl propionate, vinyl butyrate, 
vinylidene chloride, styrene, ethylene, propylene, ethyl acrylate, methyl 
methacrylate, acrylic acid, and the like. The invention is also applicable 
to mixtures containing a major proportion of a vinyl halide resin and a 
minor proportion of another synthetic resin, such as chlorinated 
polyethylene, polyacrylate resins, polymethacrylate esters, 
polyacrylonitrile, and terpolymers of acrylonitrile, butadiene, and 
styrene. Any of the well-known plasticizers for vinyl halide resins, such 
as dioctyl phthalate, dibutyl sebacate, tricresyl phosphate, and octyl 
diphenyl phosphate, can be present in the stabilized compositions. 
In addition to the aforementioned ingredients, the stabilized resinous 
compositions may contain other resin additives, such as pigments, dyes, 
processing aids, impact modifiers, extenders, and lubricants, in the 
amounts ordinarily employed for the purposes indicated. 
The stabilized vinyl halide resin compositions may be prepared by any 
suitable and convenient procedure. Such procedures include dry blending 
with a conventional mixer such as the Henschel blender, mixing on a two or 
three roll heated mill, and tumbling. 
The invention is further illustrated by the following examples.

EXAMPLE 1 
To a mixture of 300 grams of water, 407.8 grams (1.447 moles) of butyltin 
trichloride, and 225.6 grams (2.889 moles) of 2-mercaptoethanol at 
60.degree.-70.degree. C. was added over a period of 15 minutes 478.2 grams 
(2.893 moles) of a 24.2% aqueous sodium hydroxide solution. The reaction 
mixture was agitated for 30 minutes, and then there was added to it at 
55.degree.-65.degree. C. over a 10 minute period a solution of 94 grams 
(0.722 mole) of sodium sulfide (60% Na.sub.2 S) in 300 grams of water. 
After the mixture had been agitated for 15 minutes at 
55.degree.-65.degree. C., there was added to it 49.5 grams of the mixture 
of C.sub.12-15 alkanols containing 85% of straight-chain alcohols and 15% 
of .alpha.-branched-chain alcohols that is marketed as Shell Neodol 25, 
and 6.1 grams of 2-ethylhexanol. The mixture was agitated at 
55.degree.-65.degree. C. for 30 minutes and then allowed to separate into 
two layers. To the isolated organic layer was added 378.8 grams of 
hexylene glycol (2-methyl-2,4-pentanediol). After the resulting solution 
had been dried at 90.degree.-95.degree. C./75-85 mm Hg absolute while 
being sparged with nitrogen, 1.6 grams of secondary 4-methylpentyl acid 
phosphate was added to it, and the resulting solution was filtered. 
There was obtained 894 grams of a clear, light-yellow liquid that remained 
clear on standing at room temperature. This product was a solution of 
bis[monobutyltin di(ethanol mercaptide)] sulfide in a solvent that was a 
mixture of hexylene glycol, C.sub.12-15 alkanols, 2-ethylhexanol, and 
secondary 4-methylpentyl acid phosphate. It contained 19.0% Sn and 12.4% S 
(calculated, 18.3% Sn and 12.3% S). 
EXAMPLE 2 
To a mixture of 75.0 grams of water, 389.0 grams (1.281 moles) of 
dibutyltin dichloride, 132.4 grams (0.640 mole) of lauryl mercaptan 
(97.8%), and 50.1 grams (0.641 mole) of 2-mercaptoethanol at 
55.degree.-65.degree. C. was added over a 30 minute period 211.8 grams 
(1.281 moles) of a 24.2% sodium hydroxide solution. After the reaction 
mixture had been agitated at 55.degree.-65.degree. C. for 30 minutes, 
there was added to it a solution of 81.7 grams (0.628 mole) of sodium 
sulfide (60% Na.sub.2 S) in 300 grams of water. The reaction mixture was 
agitated for 30 minutes and then allowed to separate into two layers. The 
isolated organic layer was dried by heating it at 95.degree.-100.degree. 
C./75-80 mm Hg absolute while sparging it with nitrogen. After the 
addition of 2.5 grams of secondary 4-methylpentyl acid phosphate and 88.7 
grams of hexylene glycol to it, the product was filtered. 
There was obtained 573 grams of a stable, clear, light-yellow liquid which 
was a solution of [dibutyltin mono(dodecylmercaptide)][dibutyltin 
mono(ethanol mercaptide)] sulfide in a solvent that consisted of hexylene 
glycol and secondary 4-methylpentyl acid phosphate. It contained 25.8% Sn 
and 10.3% S (calculated 25.8% Sn and 10.4% S). 
EXAMPLE 3 
A mixture of 130.4 grams (0.632 mole) of isocotyl thioglycolate, 98.7 grams 
(1.264 moles) of 2-mercaptoethanol, 131.8 grams (0.632 mole) of 
butylstannoic acid, and 159.3 grams of hexylene glycol was heated at 
90.degree.-95.degree. C./110-120 mm Hg absolute and sparged with nitrogen 
until the theoretical 22.7 ml. of evolved water had been collected. To the 
resulting mixture was added 2.5 grams of secondary 4-methylpentyl acid 
phosphate. After filtration there was obtained 481 grams of a stable, 
clear, light-yellow liquid, which was a solution of monobutyltin 
mon(isooctyl thioglycolate) di(ethanol mercaptide) in a solvent that 
consisted of hexylene glycol and secondary 4-methylpentyl acid phosphate. 
It contained 14.9% Sn and 12.0% S (calculated, 15.0% Sn and 12.1% S). 
EXAMPLE 4 
A mixture of 130.4 grams (0.632 mole) of isooctyl thioglycolate, 49.3 grams 
(0.632 mole) of 2-mercaptoethanol, 159.2 grams (0.632 mole) of dibutyltin 
oxide (47.1% Sn), and 170 grams of hexylene glycol was heated at 
90.degree.-95.degree. C./120-125 mm Hg absolute and sparged with nitrogen 
until the theoretical 11.4 ml. of evolved water had been collected. After 
the addition of 2.5 grams of secondary 4-methylpentyl acid phosphate to 
it, the reaction mixture was filtered. There was obtained 482 grams of a 
stable, clear, light-yellow liquid, which was a solution of dibutyltin 
mono(isooctyl thioglycolate) mono(ethanol mercaptide) in a solvent that 
consisted of hexylene glycol and secondary 4-methylpentyl acid phosphate. 
It contained 15.5% Sn and 8.1% S (calculated, 15.0% Sn and 8.1% S). 
EXAMPLE 5 
A mixture of 130.6 grams (0.632 mole) of lauryl mercaptan (97.8%), 98.7 
grams (1.264 moles) of 2-mercaptoethanol, 131.8 grams (0.632 mole) of 
butylstannoic acid, and 159.1 grams of hexylene glycol was heated at 
90.degree.-95.degree. C./110-120 mm Hg absolute and sparged with nitrogen 
until the theoretical 22.7 grams of evolved water had been collected. 
After the addition of 2.5 grams of secondary 4-methylpentyl acid phosphate 
to it, the reaction mixture was filtered. There was obtained 485 grams of 
a stable, clear, light-yellow liquid, which was a solution of monobutyltin 
mono(dodecyl mercaptide) di(ethanol mercaptide) in a solvent that 
consisted of hexylene glycol and secondary 4-methylpentyl acid phosphate. 
It contained 15.3% Sn and 12.0% S (calculated, 15.0% Sn and 12.1% S). 
EXAMPLE 6 
A mixture of 314.3 grams (1.520 moles) of lauryl mercaptan (97.8%), 58.8 
grams (0.753 mole) of 2-mercaptoethanol, and 157.0 grams (0.753 mole) of 
butylstannoic acid was heated at 120.degree.-130.degree. C./75-85 mm Hg 
absolute and sparged with nitrogen until the theoretical 27.1 ml. of 
evolved water had been collected. To the resulting monobutyltin di(dodecyl 
mercaptide) mono(ethanol mercaptide), which had been cooled to 
110.degree.-115.degree. C., was added 2.5 grams of secondary 
4-methylpentyl acid phosphate, 44.6 grams of hexylene glycol, 39.7 grams 
of the mixture of C.sub.12-15 alkanols containing 85% of straight-chain 
alcohols and 15% of .alpha.-branched-chain alcohols that is marketed as 
Shell Neodol 25, and 4.9 grams of 2-ethylhexanol. The mixture was agitated 
until homogeneous and then filtered. 
There was obtained 582 grams of a stable, clear, light-yellow liquid, which 
was a solution of monobutyltin di(dodecyl mercaptide) mono(ethanol 
mercaptide) in a mixture of alcohols that contained secondary 
4-methylpentyl acid phosphate. It contained 15.1% Sn and 12.7% S 
(calculated, 15.0% Sn and 12.2% S). 
EXAMPLE 7 A mixture of 130.6 grams (0.632 mole) of lauryl mercaptan 
(97.8%), 49.3 grams (0.632 mole) of 2-mercaptoethanol, 159.2 grams (0.632 
mole) of dibutyltin oxide (47.1% Sn), and 170 grams of hexylene glycol was 
heated at 90.degree.-95.degree. C./120-125 mm Hg absolute and sparged with 
nitrogen until the theoretical 11.4 ml. of evolved water had been 
collected. After the addition of 2.5 grams of secondary 4-methylpentyl 
acid phosphate to it, the reaction mixture was filtered. There was 
obtained 483 grams of a stable, clear, light-yellow liquid, which was a 
solution of dibutyltin mono(dodecyl mercaptide) mono(ethanol mercaptide) 
in a solvent that consisted of hexylene glycol and secondary 
4-methylpentyl acid phosphate. It contained 15.5% Sn and 8.0% S 
(calculated, 15.0% Sn and 8.1% S). 
EXAMPLE 8 
A mixture of 100 parts by weight of polyvinyl chloride (Tenneco 225), 1.25 
parts by weight of lubricant (Wax XL-355), 1.2 parts by weight of acrylic 
resin (Tenneco Supercryl 100), 1.0 part by weight of titanium dioxide, 1.0 
part by weight of calcium carbonate, 0.35 part by weight of calcium 
stearate, and 0.40 part by weight of one of the stabilizer systems of this 
invention or a comparative stabilizer was blended in a Henschel blender at 
3000 rpm at 60.degree.-85.degree. C. until a uniform composition was 
obtained. Then 62.5 parts of the mixture was worked in a Brabender 
Plasticorder using a bowl temperature of 178.degree. C. and a rotor speed 
of 60 rpm. Samples were removed at 1 or 2 minute intervals and observed 
for color development. The results obtained are summarized in the 
following table. In this table, a rating of 1-2 indicates white; 3-4, 
off-white; 5-6, slightly yellow; and 7-8, yellow. 
______________________________________ 
Color Development after indicated 
number of minutes in Brabender 
Plasticorder at 178.degree. C. 
Stabilizer 1 2 3 4 6 8 10 12 14 
______________________________________ 
Product of Ex. 1 
1 1 1 1 1 2 2 3 3 
Product of Ex. 2 
1 2 3 4 4 5 -- -- -- 
Product of Ex. 3 
1 1 1 1 3 5 7 8 8 
Product of Ex. 4 
3 4 5 6 7 8 -- -- -- 
Product of Ex. 5 
1 1 2 2 3 3 4 4 5 
Comparative 
Stabilizers 
Dibutyltin bis 
1 2 3 4 5 6 7 8 8 
(isooctyl thio- 
glycolate) 
Dibutyltin bis 
4 6 6 7 7 8 -- -- -- 
(dodecyl 
mercaptide) 
______________________________________ 
From the data in the foregoing table, it will be seen that the compositions 
containing the stabilizers that are the products of Examples 1, 3, and 5 
were far superior in early color and color hold to those that contained 
the comparative stabilizers, both of which are widely used commercially in 
rigid polyvinyl chloride formulations that are used in the production of 
pipe and bottles. The composition stabilized with the product of Example 2 
also had better early color and color hold than those containing a 
comparative stabilizer, while that stabilized with the product of Example 
4 was superior in early color and color hold to that containing dibutyltin 
bis lauryl mercaptide.