Note: Descriptions are shown in the official language in which they were submitted.
5~i59i~ l
BAC~GROUND OF TI~E INVENTION
It is well-known in the art that organotin sulfur-
containing compounds such as the organotin mercaptides are
among the most efficient (by weight) heat stabilizers for vinyl
halide resins. Many such organotin compounds are even now
perhaps widely recognized as the best available singl0-compound
stabilizers for polyvinyl chloride resins. Among the organotin
sulfur-containing compounds which have been proposed for the
stabilization of polyvinyl chloride resins are organotin mercap-
tides, organotin mercaptoacids as described in U~ S. Patents
Nos. 2,641,588; 2,648,650; 2,726,227; 2,726,254; 2,801,258;
2,870,119; 2,891,92~; 2,914,506 and 2,954,363; ~he organotin
mercaptoacid esters as described in Patent 2,641,596; organotin
esters of mercapto alcohols of U. S~ Patents Nos. 2 r 8? o, 119;
2,870,182; 2,872,468 and 2,883,363; and organo thiostannoic
acids such as butyl thiostannoic acid as disclosed in U. S.
Patents Nos. 3,021,302; 3,413,264i 3,424,712 and 3,424,717.
- ; All of these organotin compounds have in common a
sulfur-containing radical or atom attached to the tin through
the sulfur atom and a hydrocarbon or substituted hydrocarbon
group directly attached to the tin through a carbon atom.
This combination of radicals has heretofore been recognized as
giving optimum stabllization from the standpoint of clarity
and heat stability. However, there are certain factors which
have limited the use of organotin sulfur-containing compounds.
Chief among these factors are their high cost. Also, sulfur-
containing radicals introduce an odor problem. Further, these
- ~k -
. -
.. . . .
3~
compounds also tend to impart poor light stability and plasticize
rigid polyvinyl chloride (PVC) compositons. Therefore, vinyl
halide resin ~ormulators have heretofore sought to overcome
such deficiencies.
In U.S1 Patent 3,764,571 by Jennings et al, organotin
stabili~er systems are described, particularly suited for the
stabilization of vinyl halide rèsins against degradation by
heat. Such stabilizer systems permit resins to be molded and
worked under the action of heat into many use~ul articles. In
accordance with that patent, a composition comprising an
organotin sulfur-containing compound, a metal carboxylate and
a metal base remarkably contributes to vinyl halide resin heat
stability. This three-component com~osition also provides for
a very efficient utilization of the rather expensive organotin
I5 sulfur-containing component. Heat stabilities were achieved with
the three-component novel compositions which are unobtainable at
the same total levels of the individual components when used
alone or in two-component combinations with one another. Also,
in copending Canadian application 197,847, filed on April 19,
1974, by Jennings, et. al., entitled "Resin Stabilizer
Systems ~f Organotin Sulfur-Containing Compounds", alkali
bisulfites were exemplified in synergistic heat-stabilizing
combinations with an organotin sulfur-containing compound.
-
2 5 SUMMARY OF THE IN~7ENTIS)N
.
The present invention is directed to further improve-
ments in resin stabilizer systems of organotin sulfur-containing
~ s~
compounds. This invention is predicated in part upon the
discovery that organotin sulfur-containing compounds in
combination with alkali metal bisulfite addition products
can be employed as heat stabilizers for resins. Furthermore,
such a stabilizer combination has been found to synergystically
extend the long term heat stability of vinyl halide resins.
Therefore, ~rom these standpoints, this invention broadens
the utility of these components, and, importantly, of the
resins containing these materials which can thereby be
molded into useful articles.
Thus, in accordance with the present teachings, a
resin stabilizer composition is provided which consists
essentially of an organotin sulfur containing compound having
a -C-Sn-S group and an alkali metal bisulfite addition
product characterized by the formula
R'
X--C - SO 3M
wherein M is an alkali metal and R or R' is selected from
the class consisting of hydrogen, hydrocarbyl and substituted
hydrocarbyl and X is selected from the class consisting of
hydrogen and hydroxyl. mhe organotin and the addition
product components are in relative amounts which together
provide a synergystic stabilizing effectiveness upon the
resin.
Equally significant is our further discovery that
the mentioned addition products in our stabilizer combination
provide a clarity in the molded resin that is otherwise
unachievable with inorganic alkali metal bisulites. For
instance, inorganic alkali metal bisulfites as reported above
in combination with organotin sulfur-containing compounds
~ _4_
7Q
:~05t~
unexpectedly extend the long term heat stability of vinyl
halide resins. However, a haziness or cloudiness accompanies
such heat stabilization upon molding the vinyl halide resins.
Such haziness does not detract from the heat stabilization
against discoloration but, in certain molding applications,
the haziness may not be accep~able. ~owever, addition
products of alkali metal bisulfites, such as aldehyde or
ketone alkali metal bisulfites, can stabilize the resin
against discoloration in combination with the organotin
compound without producing haziness or cloudiness in the
molde`d resin. Such results are clearly advantageous. Among
other advantages, the aldehyde or ketone alkali metal
bisulfites are more efficient stabilizers than the inorganic
alkali bisulfites
-4a
r' ''J ~
5~Li59'~ l
~¦ in combination w~th organotin sulfur-containing compounds and,
¦¦ thus, smaller amounts of alkali metal in the resin system are
required to achieve comparable stabilization~
In the stabilizer compositions of organotin sulfur-
containing compounds and alkali metal bisùl~ite addition
products (or more simply "adducts" hereinafter) of this inven-
tion, the benefits of stabilization can be realized over broad
ranges of both total parts by weight of the stabiliæer composi-
tions in the vinyl halide resin and the weight ratios of each of
~he components with respect ~o the other. Particularly useful
stabilizer compositions of this invention are achieved with a
total parts by weight range on the order of about 0.2 to about
15 parts by weight based upon 100 paxts by weight (phr) of the
vinyl nalide resin. A most useful range of total parts by
weight of stabilizer compssition is on the order of about 0.5
to about 10 phr and this depends upon the desired heat stability
in a particular vinyl halide resin composition consistent with
- other requixements and economies. There are certain generally
preferred weight ratios of an organotin sulfur-containing com-
pound relative to a particular alkali metal bisulfite adduct.This will become apparent in view of the detailed operating
examples. However, it is to be emphasized that the most desirable
weight ratios of each of the essential components of the compo-
si~ion of this inventisn for a particular application and resin
system can be arrived at in accordance with the teachings of this
invention. Thus, in i~s broader aspects, this invention is
not limited to weight ratios of components. It has been found
. ' . ~
1~ 105~iSg~ I
that synergistic stabilization levels of a particular carbonyl
metal bisulfite and a particular organotin sulfur-containing
compound will vary as exemplified hereinafter. In general,
the combination of an alkali metal bisulfite adduct with the
organotin sulfur-containing compound is utilized at total
parts on the order of about 0.2 to about 15 phr; and approximate
weight ratio of the alkali metal bisulfite adduct to the organotin
component is in the range of about l:lOto about 10:1, respectively .
AI~ALI ~ TAL ~ISULF'ITE ADDITION PRODUCTS
Aldehyde or ketone alkali metal bisulfites and their
methods of preparation are kno~7n. Typically a saturated solution
of sodium bisulfite forms crystalline addition products with
aldehyde. Such an addition product is simply known as
"aldehyde sodium bisulfite". The formation of bisulfite addition
compounds is not only a general reaction of aldehydes, but most
methyl ketones, low-molecular weight cyclic ketones, e.g ,
cyclohexanone J cyclooctano~e, and certain other compounds having
reactive carbonyl groups behave similarly. Herein the term
"carbonyl alkali metal bisulfite" applies to such products
`generally. The addition of alkali metal bisulfite occurs in
the mentioned products at the carbonyl group. However, it is
also recognized that such addition can occur at another organic
functional group such as a reactive double bond, epoxide group,
or the like. Several reaction equations ~lhich illustrate the
reaction ta~ing place during the production of such adducts are
as follows;
_. ~ _
s~
(1) CH20 ~ NaHS03 ~` H-C-OH
S03Na
fH3
~2) ~CH3) 2CO-~NaEISO3 - ~ CH3-C-OH
03Na
H
(3) CH3CHO ~ NaHSO3 CH3-C-OH
S03Na
~4) ROOC-CH Rooc-cH-so3Na
+ NaHS03 ~ l
ROOC--CiI ROOC--CH2
(S) H2C-CH2 + NaHS03 ~ HO-CH2-CE12-S03Na
_ . . .. _
~ 5~S~
Addition products o~ the abov~ type may be characterized
by the formula:
X C ~ 503M
where M is an alkali metal and R or R' is an atom, radical or
group selected from the class of hydrogen, hydrocarbyl or substi-
tuted hydrocarbyl including alkyl, carbocyclic, arylalkyl, aryl,
hydroxyalkyl, ester, etc., and where X is hydrogen or hydroxyl.
For a discussion of the aldehyde or ketone bisulfite
addition reaction, reference is made to Shriner, et. al., "The
Systematic Identification of Organic Compounds 1l, 4th Ed., John
Wiley & Sons, Pp. 149-150 (1956) and Brewster, "Organic Chem stry",
2nd. Ed., Prentice-Hall, Pp. 158-159 (1955). Examples of such add-
ition products include acetone sodium bisulfite, cyclohexanone sodium
or potassium bisulfite, glysxal sodium bisulfite, for~aldehyde
sodium bisulfite, benzaldehyde sodium bisulfite and acetaldehyde-
sodium bisulfite. However, in its broader aspects, the invention ,
is not limited to such specific compounds in our resin stabili~ersi
- 20 Oth~r equivalent alkali metal bisulfite addi~ion products can be
used as will become apparent in view of the operating examples
and detailed description of this invention. The carbo~yl alkali
metal bisulfites have been found to provide synergistic results
in oombination with the organotin sulfur-containing compounds and
ars pxesently preferred. Further, the carbonyl sodium bisulfites
are presently preferred over the carbonyl potassium bisulfites
because of the~r mor pronounced synergisms with the organotin
- c~mponent and greater efficiency i~ ~le vinyl halide resin com-
positions in co~parison to, for example, inorganic sodium
bisulfite.
ORG~NOTIN SULFUR-CONTAINING COMPONENT
__
The organotin sulfur-containing compounds which are
~f use in this invention are generally characterized as having
a sulfur-containing radical or atom attached to the tin through
the sulfur atom and a hydrocarbon or substituted hydrocarbon
group directly attached to the tin through a carbon atom, i.e.,
compounds containing the -C-Sn-S group, These compounds can
also be characterized by the formula R-Sn-S wherein R represents
a mono or polyvalent hydrocarbon or non-hydrocarbon substituted
hydrocarbon radical. AS mentioned, this combination of R-Sn-S
bonds has been heretofore recognized as giving optimum stabili-
zation, The tin bonds are usually derived from polyvalent tin
by having at least one valence for bonding to the sulfur atom
while the remaining valence or valences are for bonding with a
hydrocarbon radical. Tin usually acts as a bi- or tetra- valent
atom, but coordination complexes of tin are known where the tin
behaves in even a higher valence state and, therefore, the
va~ence state of tin can vary in the organotin compounds which
can be used in this invention.
Generally, however, most organotins suitable for use
in this invention are derived from tetravalent tin. Of the
types of organotin compounds contemplated, included are organotin
mercaptides which may be characterized by the Formula I:
R Sn(SR')
x 4-x
wherein R and R' represent hydrocarbon or substituted hydrocarbon
radicals selected from the group consisting of alkyl, aryl,
~g _
oxyalkyl, oxyaryl and the ~urfuryl and tetrahydrofurfuryl radi-
cals, and x is an integral number from 1 to 3. Examples of such
groups are alkyls such as methyl, ethyl, butyl, ectyL, dedecyl
and octad~cyl; aryls such as phenyl, tolyl, naphthyl or xylyl;
oxyalkyl and oxyaryl, such as propyloxide, butyloxide, octylo-
xide, benzyloxide; and the furfuryl and ~etrahydro~urfuryl groups.Specific examples of organotin mercaptides in which R and R' are
butyl, for example, and x varies from 1 to 3 are monobutyltin
tributylmercaptide, dibutyltin dibutylmercaptide and tributyltin
monobutylmercaptide, Patents exemplifying this formula ~
R Sn(SR') or a similar ormula and a definition of compounds
x 4-x
represented thereby include U.S. Patents 2,641,588; 2,641,596;
2,648,650; 2,726,254 and 2,789,963, among others,
While the simplest representatives of the organotin
sulfur-containing compounds are the organotin mercaptides of
the Formula I, RxSn(SR')4 x' as stated herein aboue, the important
components of the compounds are the organotin group and the
tin-sulfur group. The organotins are therefore, not limited to
the components of this formula, but are shown by all compounds
in which a sulfur atom or mercapto radical is bound through the
sulfur atom to the tin atom of-the organotin radical, i.e.,
those organotins containing the R-Sn-S bonds. These compounds
may be further defined by the Formula II:
z
R" - Sn ~X
R" '
wherein R", R''', SX and Z have the following significance:
--10--
5ti5~Z
R" and R " ' may be different monovalent hydrocarbon radicals or
substituted hydrocarbon radicals, but will be generally the same
radicals because the starting materials for the preparation of
the organotin mercapto compounds will be generally the di-(or tri-
hydrocarbon ti~ halides or oxides available in commerce. The
nature of these groups has in most cases no, or only a very minor,
influence on the properties of the end products. R" and Rl'l may
be aliphatic, aromatic, or alicyclic groups such as methyl,
ethyl, propyl, butyl, amyl, hexyl, octyl, lauryl, allyl, benzyl,
phenyl, tolyl, naphtyl and cyclohexyl,`or substituted hydrocarbon
groups of these groups having -OH, -NH2, -CN, etc., radicals in
the molecule such as cyanoethyl (of the type described in
U. S. Patent 3,47},538) and the like.
The group SX of Formula II, for instance, may be
sulfur albne, the rest of a mercaptan, or a mercapto alcohol, or
of an ester of a mercapto alcohol or mercapto acid. The patents
mentioned above in the background of the invention give examples
of this. Aliphatic and aromatic mercaptans may be employed to
form the group SX. In the case of aliphatic mercaptans, those
having 8 to 18 carbon atoms, e.g., decyl or dodecyl mercaptan are
usually preferred because the lower mercaptans are unsuitable
for the preparation and use of the stabilizers on account of
their offensive smell. Suitable aromatic mercaptans are, for
instance, thionaphthol, thiobenzyl alcohol, phenoxyethy~ mercap-
tan, phenoxyethoxyethyl mercaptan, and others. As examples of
suitable mercapto alcohols, monothioethylene glycol, monothio-
propylene glycol, thioglycerol, thiodiethylene glycol, and others
,,. ,, _ ,._ . ..................... ... , ~_ _.
, .
- . . ~ ,.
~ ` ~
may be mentioned. Particularly suitable are the esters of these
mercapto alcohols in which the hydroxy groups are esterified by
an aliphatic, aromatic, or alicyclic saturated or unsatura~ed
monocarboxylic acid. Readily available mercaptoacid esters are
the esters of thioglycolic acid, such as ethyl thioglycolate,
isooctylthioglycolate, and generally the esters of mono and
dibasic aliphatic and aromatic mercapto acids, such as esters of
beta thiopropionic acid, thiolactic acid, thiobutyric acid and
mercapto lauric acid. It will be understood that the recited
examples for group SX apply to SR' of Formula I and ~he examples
of R" or R''' apply to R or R' of Formula I.
The group Z of Formula II may be a monovalent hydro-
carbon radical like R" and R " ', in which case the compound is
a tri-hydrocarbon tin mercapto compound. The three hydrocarbon
groups may have the same or different composition. Z may also
be a sulfur alone or the rest of a mercapto compound linked
through the S atom to the tin atom, in which case it may have the
same composition as SX or a different composition. The former
case represents a dihydrocarbon tin dimercapto compound and the
latter case represents a mixed mercapto derivative of the
dihydrocarbon stannanediol. In another sub-group, 2 may be the
rest of an alcohol or of a carboxylic acid linked through the )~i
oxygen-~of the alcoholic hydroxyl group or of the carboxylic acid
group to the tin atom. Such compounds can be defined as mono-
esters or monoethers of hydrocarbon substituted stannanediol, inwhich the second hydroxyl group of the stannanediol is replaced
by a mercapto compound. Thio alcohols and acids which are
capable of
3~
-12-
l r-
`` 1~ti5~'~
forming such ether and ester groups are illustrated in the patents
cited in the bac~ground of this invention along with their methods
of preparation. Oth~r specific references to organotin sulfur-
containing compounds as widely described in the patent art
include U. S. Patent 2,641,588, col. 1, lines 32-53 to col. 2,
lines 13-46; U. S. Pa~ent 2,641,596~ col. 1, lines 10-44; U. S.
- Patent 2,726,254, col. 1, line 63 to col. 2, line 19; U. S.
Patent 2,789,963, col. 2, lines 35-60; U. S. Patent 2,914,506,
col. 1, lines 59 to ~ol. 4, line 8; U. S. Patent 2,870,119,
col. 1, lines 27-53 and U. S. Patent 3,126,400, col. 1, lines
21-61. Other patents exemplifying these organotin sulfur-
containing compounds include U. S. Patents Nos. 3,069,447;
3,478;071; 2,998,~1; 2,809,956; 3,293,273; 3,396,185; 3,485,794;
2,830,067 and 2,855,417.
Other organotin sulfur-containing compounds which are
within the scope of this invention are characterized by the
following Formula III:
. (Rsnsl.5)n
wherein R is defined as above, S is sulfur and n is an integral
number from about 2 to about 1000. These polymeric compounds
are described in the patent literature0 for example, at U. S.
Patent 3,021,302 at col. 1, line 60 to col. 2, line 17;
U. S. Patent 3,424,712 at col. 3, line 34 to col. 4, line 2;
U. S. Patent 3,424,717 at col. 3, line 13 io col. 4, line 21.
Specific reference is made to these patents at the referenced
col~mns for more details. Other polymeric tin mercaptide type
compounds having the R-Sn-S bonds characterizing the organotin
_,_ __,_ _ , , _
sulfur-containing compounds suitable for use in this invention
are exemplified in U.S. Patents ~,809,956; 3,293,273; 3,396,185
and 3,485,794, specific examples of organotin sulfur-containing
compounds include dibutyltin bis (isooctylthioglycolate), dimethyl-
tin (isooctylthioglycolate), dioctyltin (isooctylthioglycolate),
monomethyltin tris (isooctylthioglycolate), monobutyltin tris
(isooctylthioglycolate?, dibutyltin dilaurylmercaptide, butyl
thiostannoic acid and dibutyltin bis (isooctyl-beta-mercapto-
propionate).
Of course, it is obvious that organotin mercaptides,
organotin mercapto acids, organotin mercaptoacid esters, etc.,per se form no part of this invention and the mentioned patents
and their specific disclosures clearly teach these compounds
and their method of production to ena~le anyone of ordinary
skill to use them in carrying out this inv~ntion. Other litera-
ture feferences which pertain to the organotin sulfux-containing
component having the R-Sn-S group to exemplify the scope intended
for this component in accord with the principles of this invention,
include "The Development of-The Organotin Stabilizers", by
H. Verity Smith, Tin Research Institutel Greenford, Middlesex,
Pp. 15-22, (December, 1959).
The principles of this invention and itssoperating
par~meters will be further understood with reference to the
following detailed examples which serve to illustrate the types
of specific materials and their amounts as used in typical vinyl
-14-
5~
¦¦halide resin formulations an~ the synergisms displayed by the
¦¦ essential combination of components in the stabilizer composition
according to this invention. These examples ar~ considered to
be exemplary of this invention, and should not be considered as
limiting, especially in view of applicants' broad disclosure
of principles of this invention.
In the exa~ples which follow, a standard resin
formula was employed which contained ~00 parts by weight of
polyvinyl chloride homopolymer which is characterized as a white
powder having a particl~ si2e such that 100% passes through a
42 mesh screen at a specific gravity of 1.40 (Geon }03 EP by
B. F. Goodrich). Included in the standard resin formula is also
6 parts by weight of a processing aid which is an acrylic polymer
in powdered form which improves the hot processing of rigid
and plasticized vinyl compounds. (Acryloid K12ON by-Rohm and-
Haas Company). This material is a fine, white free-flowing -
powder having a bulk density at about 0.30 gr~ms per cc and a
viscosity, 10% in toluene, at 600 cps (Brookfield). The
processing aid merely fa~ilitates hot processing and forms no
part of this invention. A paraffin wax lubricant, i.e., a
commercial wax designated 165 ~H. M. Royal, Inc.) was also
employed at 2 parts by weight in the resin for~ula. The term
"standard resin blank" or just "blank" is used hereinafter ~o
designate the standard resin formula without heat stabilizer
additives. Various combinations of the oroanotin sulfur-
containing compounds and carbony} a~kali metal bisulfites were
mixed into ~he standard resin formula ccordiny to the following
examples on a parts by weight basis. All amounts of such
* Trademark
~1 -15- L
~s`~
stabilizer components, in the tables and examples unless other-
wise indicated, are on a parts per hundred resin basis, or as
indicated above, simply "phr". The blank resin formula with and
without stabilizer additives are $ested in the followin~ examples
by first milling the mixtures to form a uniform polyvinylchloride
composition for five minutes at 350F. after which time long
term heat stabilities of test samples were determined by oven
treatment at eithar of two temperatures, 375F. or 400F as
indicated. The heat stability contribution of the stabilizer
compositions (or components thereof~ hereinafter are determined
by ascertaining the number of mlnutes at the test temperature re-
quired for the samples to turn very dark o~ black. Thus, the term
"heat stability contribution" is used to indicate the amount of
heat stability in minutes contributed by a composition or compo-
nent to the resin blank formula.
ExAMæLEs l-ll
Examples l-ll demonstrated the synergistic combination
of an organotin sulfur-containing compound and a ketone addition
product of sodium bisulfite. For this purpose, acetone sodium
bisulfite was tested alone, and at various levels in the range
of 0.25-1.75 phr with dibutyltin bis (isooctylthioglycolate),
i.e., "DBT" at various levels in the range of about 1.75-0.25
phr. Also, DBT was tested alone at 0.5, l.0 and 2;?phr. The stan-
dard resin formula was prepared as above except that l part byweight of wax was substituted for 2 parts of wax. Milling of all
samples in the series took place for 5 minutes at 350F., after
which 400F. oven heat stability tests were performed. The con-
tributions of the acetone sodium bisulfite alone, DBT alone and
various combinations of the two components to the heat stability
of the standard
65~2
resin blank are reported ln Table I.
. ~ __
;
-
~05~5~
TABLE I
400 F
~eat
Components Stability
Contri~ution
. Example 12.0 acetone sodium
- bisulfite 0-5'
Example 21.75 acetone sodium
bisulite 25'
0.25 DBT
Example 31.5 acetone sodium
; bisulfite 30'
O.S DBT
Example 41.25 acetone sodium
bisulfite 30-35'
0.75 DBT
Example 51.0 .acetone sodium
bisulfite 30-35'
1.0 DBT
Example 60.75 acetone sodium
: bisulfite 30-35'
; 1.25 DBT
- Example 70.5 acetone sodium
bisulfite 30-35'
1.5 DBT
Example 80.25 acetone sodium
bisulfite 30-35'
1.75 DBT
Example 92.0 DBT 30-35'
Example 101.0 DBT 20 '
Example 110.5 DBT ~ 5'
--18--
I ` ~l(15~59i~
~ eferring to Table I, the ketone addition product of
sodium bisulite contributed synergistically with an organotin
sulfur-containing compound as a stabilizer for vinyl halide
resins. Example 1 demonstrated that acetone sodium bisulfite
alone made no material contribution to the standard resin blank.
On the other Aand, the DBT alone at 2.0, 1.0 and 0.5 phr respect-
ively, contributed 30~35 minutes, 20 minutes and lS minutes of
heat stability to the resin blank under conditions of tests
tSee Examples 9-11). However, co~binations o~ acetone sodium
~isulfite a~ levels of 0.25 - 1~75 phr, with the organotin com-
pound at levels of 1.75 - O.25 phr, synergistically enhanced
heat stability. Even though the levels of the organotin were
reduced from 2 phr to 0.25 phr, with increasing amounts of the
o~herwise ineffective acetone sodium bisulfite from 0.25 to 1.75
phr, long term heat stability was maintained. Furthermore,
comparison of Examples 9-11 with Examples 1, 3 and 5 demonstrates
the unexpected contribution of the combination.
EX~IPLES 12-18
In a manner similar to Examples 1-11, other carbonyl
sodium bisulfites were employed in combination with the organotin
~ulfur-containing compound for the purpose of demonstrating their
synergistic behaviors. The standard resin formula was prepared
as above except 1 phr calcium stezrate was substituted for the
wax. Heat stability tests were performed for the organotin
sulfur-containing compound (DBT) in combination with sodium
bisulfite, cyclonexanone sodium bisulfite, glyoxal disodium bisul-
fite, acetaldehyde sodium bisulfite, acetone sodium bisulfite and
formaldehyde sodium bisulfite. The results are reported in Table
II.
. . . , , . ~ : .
~LOS~i~9~
TABLE II
400 F
Heat
Components Stability
Contri~ution
.. . ~ . . . . .
Ex~ttple 12 1.0 DBT 30'
Exantple 13 1.0 DBT
1.5 sodium ~isulfite 40'
Example 14 1.0 DBT
1.5 cyclohexanone 50'
sodium bisulfite
: Exantple 15 1.0 DBT
1.5 glyoxal di sodium 40'
bisulfite
Example 16 1.O DBT
1.5 acetaldehyde 50-60'
sodiunt bisulfite
.
Example 17 1.0 DBT
1.5 acetone sodium 50-60'
bisulfite
Example 18 1.O DBT
105 formaldehyde 50'
sodium bisulfite
-20-
. . ~ . ,
~s~
Table II demonst~ates that various carbonyl sodium
bisulfites behave as acetone sodium bisulfite with an organotin
sulfur-containing compound. The ketone and aldehyde sodium
bisulfites of Examples 14-18 demonstrated a synergi~tic behavior
with the organotin component at least as good or better than
sodium bisulfite. Synergism with the glyoxal di-sodium bisulfite
and the organotin compound was observed in Example 15, comparable
to sodium bisulfite of Example 13. However, the synergisms of
tha other carbonyl sodium bisulfites were 10-20 minutes greatex
than Example 13.
The compositions of the Examples 12-18 were tested for
clarity by pressing out such compositions for about 5 minutes
at 350F. In comparison to the pressed formula of Example 13
containing sodium bisulfite which exhibited particulate opacity,
improved clarity was observed with the ketone or aldehyde sodium
bisulfites of Examples 14-18. Accordingly, when long term heat
stability is desired with clarity, the ketone and aldehyde
sodium-bisulfites are very advantageously employed according to
the principles of this invention.
ExAMoeLEs 19-25
The formulation and heat stability procedures of
Examples 12-18 were performed again except that the amounts of
the sodium bisulfite and all carbonyl sodium bisulfites were
adjusted to provide the same ~odium metal content in each
Example 19-25. Then, the long term heat stabilities of the
resultant vinyl halide resin compositions were observed and the
results are reported in Table III.
-21-
~)s~
T~BLE III
400 F
~eat
Components Stability
Contribution
~:xample 1~ 1. O DBT 35 '
Example 2 0 1. 0 DBT
~ 1.0 sodium bisulfite 40'
- Example 21 1.0 ~BT
2.1 cyclohexanone ~50'
sodium bisulfite
Example 22 1.0 DBT
1.15 glyoxal di- 4O '
. sodium bisul~ite
Example 23 1.0 DBT
: 1.5 acetaldehyde > 50'
sodium bisulfite
Example 24 17 0 DBT
` 1. 65 acetone sodium >50'
bisulfite
Example 25 1.0 DBT
1.35 formaldehyde >50'
. . sodium bisulfite
-22-
_, . _ .. _ _ _. . . . _ _. , . ~
Examples 20-26 of Table III demonstrated that the
sodium metal in the carbonyl ~odium bisulfite is generally more
efficient in heat stabilization than the sodium metal in the
inorganic sodium bisulfite. With the exception of glyoxal
di-sodium bisulfite (Example 22) because of its incomplete
compatability in the PVC resi~ composition as demonstrated
by plate-out on the mill rolls, the carbonyl sodium bisulfites
of Example 21, 23-25 out-performed the sodium bisulfites at
the same levels of sodium metal. The sodium bisulfite of
Example l9 exhibited earlier discoloration and finally degradation
at about 40 minutes whereas Examples 21, 23-25 did not signifi-
cantly discolor even after 50 minutes. These examples also
demonstrated that variations in the metal content of the carbonyl
sodium bisulfites can be made in accordance with the principles
of this invention and the advantageoud results maintained.
EXAMPLES 27-35
Examples 27-35 further illustrate the practice of
this invention. The standard resin formula was used in these
examples with various carbonyl alkali metal bisulfites in phr
alone and in combination with an organotin sulfur-containing
compound (DBT). Heat stability contributions were determined
by milling at 350F and-oven testing-at~375F. iThe rësults
are reported in Table IV.
-23,
1(~5~59'~
.
TABLE IV
375 F
~eat
Components Stability
Contribution
Example 27 0.5 DBT 20'
Example 28 1.0 cyclohexanone
potassium bisulfite 0'
- Example 29 1.0 cyclohexanone
sodium bisulfite 0'
Example 30 0.5 DBT
1.0 cyclohexanone
potassium bisulfite 40'
Example 31 0.5 DBT
1.0 cyclohexanone
sodium bisulfite 80'
Example 32 0.5 DBT
1.0 glyoxal di-sodium
bisulfite 50
Example 33 0.5 DBT
1.0 acetaldehyde
` sodium bisulfite 70'
.
Example 34 0.5 DBT
1.O formaldehyde
sodium bisulfite 60'
Example 35 - 0.5 DBT
1.O benzaldehyde sodium
bisulfite 50'
- -24-
` ~ 5~
Examples 27-35 confirmed the heat sta~ilizing effective-
ness of the carbonyl alkali metal bisulfites in combination ~Jith
the organotin component at 375 F heat stability testing. Also,
the carbonyl sodium bisulfite of Example 31 far out-performed
the potassium counterpart of Example 30. Even though synergism
was demonstrated by the potassium derivative oE Example 30, the
sodium derivative exceeded that contribution by 40 minutes.
These examples demonstrate that the carbon~1 sodium bisulfites
are presently preferred over the potassium counterparts.
~10 Furthermore, Examples 27-35, as well as the above examples,
demonstrated that the carbonyl group of the alkali bisulfite
nddition products may vary and the desired results of this
invention can still be achieved. For instance, lower alkyl
ketones, low-molecular weight carbocylic ketones, aldehydes in
general o~ the hydrocarbyl or substituted hydrocarbyl type,
arylalkyl aldehydes or ketones, etc., are among the class of
reactive carbonyl-containing compounds which form addition
products with the alkali bisulfites, particularly sodium
bisulfites. The reaction of such carbonyl compounds has becn
widely developed to identify the presence of organic carbonyl~
containing compounds as described above in the literature
references. Furthermore, as discussed above, other organic
compounds foxm addition products with alkali metal bisulfites.
Accordingly, in its broadest aspects, this in~en~ion is
predicated upon the use of reaction products or adducts of an
alkali metal bisulfite and an organic compound, especially
car`onyl ontaining compounds, in combinatlon with an organotin
~ sulfur-containing compound to either provide enhanced heat
stabilization of resins, to achieve improved clarity in molded
resin products in comparison to inorganic alkali metal bisul-
fites or to obtain a greater stabilization efficiency than such
inorganic metal bisulfites.
In each of the above examples, the vinyl halide resin
which was employed is a homopolymer of vinyl chloride, i.e.,
polyvinyl chloride. It is to be understood, however, that this
invention is not limited to a particular vinyl halide resin such
as polyvinyl chloride, of course. Other halogen-containing
resins which are employed and illustrate the principles of this
invention include chlorinated polyethylene, chlorinated polyvinyl
chloride and the vinyl halide resin type. Vinyl~halide resin,
as understood herein, and as appreciated ïn the art, is a
common term and is adopted to define those resins or palymers
usually derived by polymerization or copolymerization of vinyl
monomers including vinyl chloride with or without other comonomers
such as ethylene, propylene, vinyl acetatel vinyl ehhers,
vinylidene chloride, methacrylate, styrene, etc. A simple case is
the conversion of vinyl chloride H2C~CHCl to polyvinyl chloride
(CH2-C~Cl-)n wherein the halogen is bonded to the carbon atoms
of the carbon chain of the polymer. Other examples of such
vinyl halide resins would include vinylidene chloride polymers,
vinyl chloride-vinyl ester copolymers, vinyl chloride-vinyl
ether copolymers, vinyl chloride-vinylidene copolymers, vinyl
chloride-propylene copolymers, chlorinated polyvinyl chloride;
and the like. Of course, the vinyl halide commonly used in the
-26-
` ~ s~
industry is the chloride, although others such as ~romide and
fluoride may be used.
It is also to be understood that other components such
as lubricants, processing aids, pigments, other stabilizers,
other non-halogenated resins, etc., can be incorporated in the
resin compositions and the benefits of ~his invention can be
achieved. Accordingly, other modifications will become
appaxent in view o the teachings herein without departing from
the true spirit and scope of this invention.
'10
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.
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