GB2096148A - Stabilizers for halogenated resins - Google Patents

Abstract

Compositions for heat stabilizing halogen-containing resins are a mixture of a tin tetrakis(mercaptide) and a sulfur-containing organotin compound, and optionally a third and/or fourth component, namely an alkali or alkaline-earth metal salt of a mercaptan or mercapto acid and/or an overbased complex of an alkali or alkaline-earth metal base. These stabilizer compositions offer significant improvements in early color inhibiting performance as well as in stabilization economies by reducing the amount of tin required.

Description

SPECIFICATION Stabilizers for halogenated resins The present invention relates to a composition comprising a mixture of a tin tetrakis(mercaptide) and a sulfur-containing organotin compound.

It is well known in the industry that halogenated resins when heated tend to degrade in the absence of a heat stabilizer. When the halogenated resin degrades it turns colors normally going from white to yellow to orange to red to purple and finaily to black. Stabilizers are put in halogenated resins to prevent this color formation especially in its early stages such as when the resin is being extruded or injection molded. Some stabilizers will not allow the halogenated resin to decompose but will allow color to develop quicker than others.

The use of sulfur-containing organotin compounds as heat stabilizers for halogenated resins is well known in the art. U.S. Patent No. 4,11 5,352 discloses the sulfur-containing organotin compounds and their utility as stabilizers for halogenated resins. Although the organotin compounds are recognized as being among the most effective stabilizers for inhibiting the degradation of the halogenated resins at the high temperatures encountered during processing, many of these compounds unfortunately do not entirely prevent the early discoloration of the resins. It would be of commercial significance, therefore to provide materials that can improve the early color inhibiting performance of these stabilizers.

Tin tetrakis(mercaptides) have been proposed as stabilizers for halogen-containing resins also to protect them against degradation by heat during the fabrication of the resin into useful articles. Prior patents which dislose tin tetrakis(mercaptides) and their utility as stabilizers are U.S. 2,726,277 and 2,888,435. Also, our copending U.K. application No. 21508/78 teaches the tin tetrakis(mercaptides) as stabilizers. In commercial practice, however, the tin tetrakis(mercaptides) alone have not been used as stabilizers because their performance is far inferior to that of organotin mercaptides mentioned above (characterized by at least one C-Sn bond). In fact, in some cases the tin tetrakis(mercaptides) alone are found to actually catalyze the decomposition of the halogenated resin.

The present invention overcomes the problem of the early color syndrome as will be demonstrated in greater detail hereinafter.

The present invention is directed to a composition comprising a mixture of (a) from about 99 to about 20 weight percent of a sulfur-containing organotin compound having a -C-S n-S group and (b) from about 1 to about 80 weight percent of a tin tetrakis(mercaptide) having four Sn-S bonds. This composition can have a third and/or fourth optional component, namely an alkali or alkaline-earth metal salt of a mercaptan or mercapto acid and/or an overbased organic complex of an alkali or alkaline-earth metal base. These additional components further improve the stabilization performance especially long-term stability.

The sulfur-containing organotin compounds which are of use in the present 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-S n-S group. 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.

Organotins suitable for use in this invention are derived from tetravalent tin. The types of organotin compounds contemplated, are those reviewed in U.S. Patent No. 3,764,571, column 3, line 1 to column 5 line 55; U.S. Patent No. 2,641,588, column 1, lines 32-53 and column 2, lines 1346; U.S. Patent No. 2,641,596, column 1, lines 10--44; U.S. Patent No. 2,726,254, column 1, line 63 to column 2, line 19; U.S. Patent No.2,789,963, column 2, lines 35-60; U.S. Patent No.2,914,506, column 1, line 59 to column 4, line 8; U.S. Patent No. 2,870,119, column 1, lines 27-53 and U.S.

Patent No. 3,126,400, column 1, lines 21-61. Other patents exemplifying organotin sulfur-containing compounds include U.S. Patent Numbers 3,069,447; 3,478,071; 2,998,441; 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 (I).

(RlSnSa 5)n (I) wherein RX is as defined below, and n is an integral number from about 2 to about 1 000. These polymeric compounds are described in the patent literature, for example, U.S. Pat. No. 3,021,302 col.

1, line 60 to col. 2, line 17; U.S. Pat. No. 3,424,712 col. 3, line 34 to col. 4, line 2; and U.S. Pat. No.

3,424,717, col. 3, line 13 to col. 4, line 21. Specific reference is made to these patents at the referenced columns for more details. Other polymeric tin mercaptide type compounds having the -C-Sn-S bonds characterizing the organotin sulfur-containing compounds suitable for use in this invention are exemplified in U.S. Pat. Nos. 2,809,956; 3,293,273; 3,396,185 and 3,485,794 and these exemplifications are incorporated herein by reference.

Preferred organotin stabilizers are described by Formula II

wherein: a is 1 or 2.

R' is a hydrocarbon radical having 1-1 8 carbon atoms and is selected from the group consisting of alkyl, cycloalkyl, aryl, mixed alkyl-aryl and said hydrocarbon radicals having a substituent selected from the group consisting of -CN, -OR3,

or-CO2R3 where R3 is a 1-20 carbon atom alkyl, alkenyl, or mixed alkyl-aryl group; R2 is a hydrocarbon radical (e.g., alkyl cycloalkyl, aryl or mixed alkyl-aryl) of 1-22 carbon atoms optionally substituted by halogen, -XH, -XR3,

where R3 is as defined above and both X and Y are independently selected from oxygen (0) and sulfur (S); Z isO, S, R1, -SR2, or SSn(R1)(SR2 where b is 1 or 2.

The nature of R1 has in most cases only a minor influence on the performance of the end product.

Examples of the group R1 are methyl, ethyl, propyl, butyl, amyl, hexyl, octyl, lauryl, allyl, benzyl, phenyl, toly, naphthyl, and cyclohexyl; or a substituted hydrocarbon radial such as 2-carbomethoxyethyl, cyanoethyl (of the type described in U.S. Patent No. 3,471,538) and the like.

The group SR2 of Formula II may be derived from a mercaptan, or a mercapto alcohol, or an ester of a mercapto alcohol or mercapto acid. Aliphatic and aromatic mercaptans may be employed to form the group SR2. In the case of aliphatic mercaptans, those having 8 to 1 8 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, phenoxyethyl mercaptan, phenoxyethoxyethyl mercaptan and others. As examples of suitable mercapto alcohols, monothioethylene glycol, monothiopropylene glycol, thiogylcerol, 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 unsaturated monocarboxylic acid. Readily available mercapto acid esters are the esters of thioglycolic acid, such as ethyl thioglycoate, isooctyl thioglycolate, 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.

Of course, organotin mercaptides, organotin mercapto acids, organotin mercapto acid esters, etc., per se are not claimed for this invention and the mentioned patents and their specific disclosures clearly teach these compounds and their method of production to enable anyone of ordinary skill to use them in providing the compositions of this invention.

Especially preferred examples of organotin stabilizers are as follows: (CH3)2Sn(SCH2CO2C8H17)2 (C4H9)2Sn(SCH2CO2C8H17)2 (CH3)2Sn(SCH2CH2CO2 C8H17)2 (C4H9)2Sn(SCH2CH2CO2C8H17)2 CH3Sn(SCH2CO2C8H17)3 C4HgSn(SCH2CO2C8Ha7)3 CH3Sn(SCH2CH2CO2C8H17)3 C4H9Sn(SCH2CH2CO2C8H17)3

(CH3)2Sn(SCH2CO2C13H27)2 (C4Hg)2Sn (SCH2Co2C13H27)2 CH3Sn(SCH2CO2C13H27)3 QH9Sn(SCH2C02C13H27)3 (C8H 17)2Sn(SCH2CO2CH17)2 (CH3)2Sn(SC12H25)2 (C8H 17)2Sn(SCH2CH2CO2C8H17)2 (C4H9)2Sn(SC12H25)2 C8H17Sn(SCH2CO2c8H17)3 (CH3)2Sn(SCH2CH202Cc17H3s)2 C8H17Sn(SCH2CH2CO2C8H17)3 (CH3)2Sn(SCH2CH2O2CC17H33)2

CH3Sn(SCH2CH2O2CC17H35)3 CH3Sn(SCH2CH2O2CC17H33)3 (C4H)2Sn(SCH2CH2O2CC17H35)2 (QH9)2Sn(SCH2CH2O2CC17H33)2 C4HgSn(SCH2CH202CC17H36)3 C4HsSn(SCH2CH2O2CC17H33)3

(CH3)2Sn(SCH2C02C13H27)2 (C4Hg)2Sn(ScH2co2c13H27)2 CH3Sn(SCH2cO2c13H27)3 QH9Sn(SCH2C02C13H27)3 (C8H17)2Sn(SCH2CO2C8H17)2 (CH3)2Sn(SC12H2s)2 (C8H17)2Sn(SCH2CH2CO2C8H17)2 (C4H9)2Sn(SC12H25)2 C8H17Sn(SCH2CO8H17)3 (CH3)2Sn(SCH2CH2O2CC17H35)2 C8H17Sn(SCH2CH2CO2C8H17)3 (CH3)2Sn(SCH2CH2O2CC17H33)2

CH3Sn(SCH2CH2O2CC17H35)3 CH3Sn(SCH2CH2O2CC17H33)3 (C4H9)2Sn(SCH2CH2O2CC17H35)2 (QH)2Sn(SCH2CH2QCC17H33)2 C4H9Sn(SCH2CH2O2CC17H35)3 C4HgSn(SCH2CH202CC17H33)3 Alkali metal and alkaline earth metal salts of mercaptans and mercapto acids which may be incorporated in the composition of this invention are described in U.S. Patent No. 4,11 5,352 which is incorporated herein by reference. The above-mentioned application describes the metal salts by the formulas M(SR4)n |||

wherein M is a group IA metal (an alkali metal, in which case n=1) or a group IIA metal (an alkaline earth metal, in which case n=2); M' is a group IIA metal; R4 is a hydrocarbon radical (such as alkyl, cycloalkyl, aryl, or mixed alkyl-aryl) of 1-22 carbon atoms, optionally substituted by halogen, -XH, -XR3,

where R3 is as previously defined;X and Y are independently selected from 0 and S; and R5 is a hydrocarbon linking group of 1-5 carbon atoms (which may be part of a cyclic structure) and is optionally substituted with halogen, -XH, -XR3, or

where R3 is as described above.

In the preparation of compounds of structure VI there might be formed "polymeric" linear salts of the same empirical formula and these mixtures are operable and included in this invention.

Compositions containing more than one metal, and composition having mixed R groups, are also operable and part of this invention.

The preferred metal salts of mercaptans or mercapto acids which are optionally employed in this invention are the alkaline earth metal salts: Ca(SCH2CO2c8H17)2 Ca(SC12H2s)2 Ca(SCH2CH2CO2C8H17)2 Ba(SC12H2s)2 Ba(SCH2CO2C8H17)2

Ba(SCH2CH2C02C8H17)2 Ba(SCH2CH202Cc17H33)2

Ba(SCH2CH202CC17H35)2 Ca(SCH2CH202CC17H33)2 Ca(SCH2CH202CC17H35)2 Especially preferred because of their superior performance are the following barium and calcium salts:: Ba(SCH2CO2C8H17)2 Ba(SCH2CH2CO2C8H17)2 Ba(SCH2CH2O2CC17H33)2 Ba(SCH2CH2O2CC1 7H35)2 Ca(SCH2CO2C8H17)2 Ca(SCH2CH2CO2C8H17)2 Ca(SCH2CH2O2CC17H33)2 Ca (SCH2CH2O2CC17H35)2 The tin tetrakis(mercaptides) which are operable in this invention are characterised by having four Sn-S bonds and are defined by the formula:

wherein R6, R7, R8 and R9 are hydrocarbon radicals (e.g., alkyl, cycloalkyl, aryl, or mixed alkyl-aryl) of 1-22 carbon atoms optionally substitued by halogen, -XH, -XR3, or

where R3 is 1-20 carbon atom alkyl, alkenyl, cycloalkyl, aryl, or mixed alkyl-aryl group and both X and Y are independently selected from oxygen (0) and sulfur (S).

Examples of these tin tetrakis(mercaptide)s are: Sn(SCH3)4

Sn(SC4Hg)4 Sn(SCH2CQC8H17)4 Sn(SC12H25)4 Sn(SCH2CH2CO2C8H17)4

Sn(SQH4-p-CH3)4 Sn(SC6H4-p-Cl)4 Sn(SCH2C6H5)4

Sn(SCH2CH2OH)4 Sn(SCH3)3(SCH2CO2C20H41)

Sn(SCH2CH2SC10H21)4 Sn(SC2H4O2CC6H5)4 Sn(SC3H6O2CC1,H33)4 Sn(SC2H402CC17H35)4

Sn(SC4Hg) (SCH2CO2C8H17)3 Sn(SC8H17)2 (SCH2CO2CsH17)2 Sn(SC2Hs)2 (SC4H9)2 Sn(SCH2CO2C3H,)2 s(SCH2CH2C02C8H17)1.s Sn(SC12H25)2 (SCH2C02C4Hg)2 Sn(SC4H9)2(SCH2CO2C8H17)2 Sn(SCH2CH2SaCCH3)4 Sn(SC4Hg)3 (SCH2CO2C8H17) Sn(SC2H402CC17H33)4 Particularly preferred tin tetrakis(mercaptide)s are: Sn(SCH2CO2C8H17)4 Sn(SC12H25)2(SCH2CO2C8H17)2 Sn(SC4Hg) (SCH2CO2C8H17)3 Sn(SCH2CH2CO2c8H17)4 Sn(SC4Hg)2 (SCH2CO2C8H17)2 Sn(SC12H25) (SCH2CH2CO2C8H17)3 Sn(SC4H9)3 (SCH2CO2C8H 17) Sn(SC12H25)2 (SCH2CH2C02C8H 17)2 Sn(SC12H2s)4 Sn(SC12H2s) (SCH2CO2C8H17)3

Sn(SC2H4O2CC17H33)4 Sn(SC2H402CC17H3s)4 The tin tetrakis(mercaptide)s of this invention can be conveniently prepared by the reaction of selected mercaptans with anhydrous stannic chloride optionally in the presence of an HCI acceptor such as an inorganic or organic base.

The overbased organic complexes of alkali or alkaline earth metal bases which may also be incorporated in the composition of this invention are described in our copending U.K. Application No.

21508/78 and in United States patents cited therein. Application No. 21508/78 describes the overbased organic complex of an alkali or alkaline-earth metal base by the formula: R10n . xM1An, (Vll) wherein R10 is a residue of an organic acid selected from carboxylic, thiocarboxylic, sulfonic, sulfinic, phosphonic, phosphinic, thiophosphonic, thiophosphinic, phenolic, and thiophenolic; n and n' are 1 or2; M and M' are the same or dissimilar alkali or alkaline earth metals (group I and Ia metals of the periodic table); X is a positive number greater than zero; and, A is the anion portion of the basic material selected from OH-l, CO3-2, 0-2, SO42, SO3-2, HCO3-', 5-2 The organic complex is generally dispersed in a low-volatile liquid such as hydrocarbon oil, a plasticizer, an epoxy ester, or a combination thereof.

The fundamental technique for preparing such overbased complexes involves the preparation of a soap or salt of an organic acid in the presence of an amount of neutralizing agent, such as a metal oxide or hydroxide, which results in the formation of a stable product that contains an amount of metal in substantial excess of that which is theoretically required to replace the acidic hydrogens of the organic acid; e.g. carboxylic, phenolic, sulfonic, sulfinic, etc., used as the starting material. Generally, the stoichiometric excess of metal for the overbased complexes is at least one equivalent, as presently preferred, but can vary from about 0.1-30 equivalents.Also, the reaction product may be treated with an acidic gas (e.g., CO2) to reduce the free basicity of the complex. (The free basicity is regarded as that amount of metal base which is titratable to a pH of about 8; whereas, the total basicity of the complex is titratable to a pH of about 3.) As set forth in U.S. Patent No. 3,764,571, over-based acids wherein the acid is a phosphorus acid, a thiophosphorus acid, phosphorus acid-sulfur acid combination, and sulfur acid prepared from polyolefins are disclosed in United States Patent Numbers 2,883,340; 2,915,517; 3,001,981; 3,108,960; and 3,232,883. Overbased phenates are disclosed in United States Patent Number 2,959,551 while overbased ketones are found in United States Patent No. 2,798,852.A variety of overbased materials derived from oil soluble metal-free, non-tautomeric neutral and basic organic polar compounds such as esters, amines, amides, alcohols, ethers, sulfides, sulfoxides, and the like are disclosed in United States Patent Numbers 2,968,642; 2,971,014; and 2,989,463. Another class of materials which can be overbased are the oil-soluble, nitro-substituted aliphatic hydrocarbons, particularly nitro-substituted polyolefins such as polyethylene, polypropylene, polyisobutylene, etc.

Materials of this type are illustrated in United States Patent No. 2,959,551. Likewise, the oil-soluble reaction product of alkylene polyamines such as propylene diamine or N-alkyiated propylene diamine with formaldehyde or a formaldehyde producing compound (e.g., paraformaldehyde) can be overbased.

Other compounds suitable for overbasing are disclosed in the above cited patents or are otherwise well-known in the art.

A class of particularly suitable organic materials the residue of which may form the R'O group of the above formula for the overbased organic complex include oil-soluble organic acids, preferably those containing at least twelve aliphatic carbons although the acids may contain as few as eight aliphatic carbon atoms if the acid molecule includes an aromatic ring such as phenyl, napthyl, etc.

Representative organic acids are discussed and identified in detail in the above-noted patents.

Particularly, United States patent No. 2,616,904 and 2,777,874 disciose a variety of very suitable organic acids. For reasons of economy and performance, oil-soluble carboxylic, sulfonic, and phenolic are particularly suitable.

Within the group of overbased carboxylic, sulfonic, and phenolic acids, the barium and calcium overbased mono-, di-, and tri-alkylated benzene and napthalene (including hydrogenated forms thereof) petrosulfonic acids, higher fatty acids, and alkylated phenols are especially suitable. The petroleum sulfonic acids are a well-known class of materials which have been used as starting materials in preparing overbased products since the inception of overbasing techniques as illustrated by the above patents.

The overbased organic complexes used in the stabilizer systems of the invention usually contain from about 10 to about 70 percent by weight of metal containing components. The exact nature of these metal containing components is not known. Furthermore, the overbased organic complexes may be in colloidal non-Newtonian form as disclosed and described in United States Patent No. 3,384,586 in contrast to single phase homogeneous systems. However, this depends upon the reaction conditions and the choice of reactants in preparing the overbased materials. Sometimes there are present in the product insoluble contaminants. These contaminants are normally unreacted basic materials such as calcium oxide, barium oxide, calcium hydroxide, barium hydroxide or other metal base materials used as reactants in preparing the overbased material.It should be understood however, that the removal of these contaminants is not absolutely essential to the performance of this invention.

The metal compounds used in preparing the organic overbased complexes are the basic salts of metals in Group land Group Ia of the Periodic Table such as Na, K, Ca, Ba, Mg and Sr. The anionic portion of the salt can be hydroxyl, oxide, carbonate, bicarbonate, sulfite, sulfide, sulfate, as disclosed in the above cited patents.

The preferred overbased organic complexes are those overbased with CaCO3 and BaCO3; especially preferred is BaCO3.

The stabilizer composition of this invention can be used over a range of about 0.05 to about 10 phr (that is, parts by weight per 100 parts) of halogenated resin. The preferred range is about 0.25 to about 5.0 phr.

The four components are generally combined in the weight-percent amounts as follows: wP/O tin tetrakis(mercaptide)s 180% sulfur-containing organotin compound 9920% alkali or alkaline earth metal salt of a mercaptan or a mercapto acid 0-60% overbased organic complex of an alkali or alkaline earth metal base. 0-60% 100 Preferred weight-percent ranges are as follows: wt% tin tetrakis(mercaptide)s 150% sulfur-containing organotin compound 99 40% alkali or alkaline earth metal salt of a mercaptan or a mercapto acid.O- 00% overbased organic complex of an alkali or alkaline earth metal base. 0 40% 100 The novel stabilizer compositions of this invention can be used with halogen containing vinyl and vinylidene resins in which the halogen is attached directly to the carbon atoms.

As the halogen resin there can be employed chlorinated polyethylene having 14 to 75%, e.g., 27% chlorine by weight, polyvinyl chloride, polyvinylidene chloride, polyvinyl bromide, polyvinyl fluoride, polyvinylidene fluoride, copolymers of vinyl chloride with 1 to 90%, preferably 1 to 30% of a copolymerizable ethylenically unsaturated material e.g., vinyl acetate, vinyl butyrate, vinyl benzoate, vinylidene chloride, diethyl fumarate, diethyl maleate, other alkyl fumarates and maleates, vinyl propionate, methyl acrylate, 2-ethylhexyl acrylate, butyl acrylate and other alkyl acrylates, methyl methacrylate, ethyl methacrylate, butyl methacrylate and other alkyl methacrylates, methyl alpha chloroacrylate, styrene, trichloroethylene, vinyl ethers such as vinyl ethyl ether, vinyl chloroethyl ether and vinyl phenyl ether, vinyl ketones such as vinyl methyl ketone and vinyl phenyl ketone, 1-fluoro-1- chloroethylene, acrylonitrile, chloroacrylonitrile, allylidene diacetate and chloroallylidene diacetate.

Typical copolymers include vinyl chloride-vinyl acetate (96:4 sold commercially as VYNW), vinyl chloride-vinyl acetate (87:13), vinyl chloride-vinyl acetate-maleic anhydride (86:13:1), vinyl chloride vinylidene chloride (95:5), vinyl chloride-diethyl fumarate (95:5), vinyl chloride-trichloroethylene (95:5), vinyl chloride-2-ethylhexyl acrylate (80:20).

Preferably the resin is a vinyl halide resin, specifically, a vinyl chloride resin.

The stabilizer composition of the present invention can be incorporated with the resin by admixing in an appropriate mill or mixer or by any of the other well-known methods which provide for uniform distribution throughout the resin compositions. Thus, mixing can be accomplished by milling on rolls at 1000--1600C.

In addition to the novel stabilizers there can also be incorporated with the resin conventional additives such as plasticizers, conventional stabilizers, antioxidants, pigments, fillers, dyes, ultraviolet light absorbing agents, densifying agents and the like as identified and in the amounts set forth in U.S.

Patent Number 3,925,309.

The invention will be further understood by reference to the following Examples which serve to illustrate, but not limit, the invention.

Example 1 Preparation of tin tetrakis(isooctyl thioglycolate) To a mixture of 81.7 g (0.4 mole) of isooctyl thioglycolate and 26.1 g (0.1 mole) of anhydrous stannic chloride dissolved in 250 ml of hexane, is added a solution of 40.5 g (0.4 mole) of triethylamine in 100 ml of hexane. The mixture is stirred at room temperature for three hours and then filtered. The filtrate is concentrated under reduced pressure to give 81.0 g (87.0% yield) of product. Infrared data is consistent with the assigned structure.

Anal. Calcd.forC40H76O8S4Sn: C,51.6; H,8.22; S,13.8; Sn,12.7 Found: C,52.6; H,8.37; S,13.6; Sn,11.4 Example 2 Preparation of tin tetrakis(2-mercaptoethyl stearate) Ammonia (7.0 g; 0.41 mole) is bubbled through a solution of 137.8 g (0.4 mole) of 2 mercaptoethyl stearate and 26.1 g (0.1 mole) of anhydrous stannic chloride dissolved in 470 ml of toluene. The reaction mixture is then heated under reflux for three hours, cooled, and filtered. The filtrate is concentrated under reduced pressure to give 123.6 9 (82.0% yield) of product. Infrared data is consistent with the assigned structure.

Anal. Calcd. for C80H,56S408Sn: C, 64.4; H, 10.5; S, 8.59; Sn, 7.95 Found: C, 65.5; H, 10.6; S, 7.79; Sn, 6.82 Example 3 Preparation of barium carbonate dispersion (over-based organic complex) In a three necked, round-bottomed flask equipped with a mechanical stirrer, Dean-Stark trap, and a stopper, a stirred mixture of: 57 g of nitrated polyisobutylene; 133 g of a light paraffin oil; 50 g of isooctyl alcohol; 60.8 g (0.28 eq.) of p-nonylphenol; and 138.7 g (1.6 eq.) of barium hydroxide monohydrate is heated to 1 500 and maintained at that temperature for five hours to drive off the water. Thereupon. the reaction mixture is gassed with carbon dioxide at a rate of 19 g/hr for three hours at 1 500 C. The isooctyl alcohol and excess water are then vacuum stripped and the product filtered. The yield of product, a dark, viscous solution, is 341.3 9 (84.5%).

Theory: Ba, 27.7%; CO-2, 10.0% Found: Ba, 23.1%; CO32, 8.45% Examples 4--17 In the following examples, a standard single-screw pipe formulation is used which contains 100 parts by weight of a polyvinyl chloride homopolymer (VC 100 PM, Borden Chemical Co.); 3.0 parts by weight of a processing aid which is an acylic polymer consisting of 90% methyl methacrylate and 10% ethyl acrylate (K-120N, Rohm and Haas Co.); 0.5 parts by weight of a paraffin wax (Rosswax 165, F. B.

Ross Co.); 0.2 parts by weight of a partially saponified ester wax (Wax OP, American Hoechst Co.); 1.4 parts by weight of calcium stearate; 2.0 parts by weight of titanium dioxide; and stabilizer as indicated (all amounts in parts by weight).

The resin mixtures are dryblended in a Waring Commercial Blender and their dynamic heat stability determined on a Brabender Plastograph using a 67.5 g charge, 41 50F stock temperature, and 40 rpm mixing head speed. Samples are withdrawn from the Brabender at three minute intervals. The discoloration of the sample is rated visually and recorded according to the following abbreviations: Color Degree G-gray L-light Pk-pink P-pale W-white V-very Y-yellow Stabilizers are abbreviated as follows:: DMTG-Dimethyltin bis(isooctyl thioglycolate) MTMS-Methyltin tris(2-mercaptoethyl stearate) TTTG-Tin tetrakis(isooctyl thioglycolate) TTMS-Tin tetrakis(2-mercaptoethyl stearate) BBM S-Barium bis(2-mercaptoethyl stearate) Table 1 Example Time (Minutes) No. Parts Stabilizers 3 6 9 12 15 4 - None PK G - - 5 1.5 DMTG W W VPY VPY PY 6 1.5 TTTG G - - - - 7 1.35 DMTG w w w VPY PY 0.15 | | IG 8 1.20 DMTG W W W W PY 0.30 TTTG 9 1.20 DMTG W VPY VPY VPY PY 0.30 BaCO3 overbase complex 10 0.90 DMTG W W W W VPY 0.30 BaCO3 overbased complex 0.30 TTTG 11 1.5 MTMS W W W Y G 12 1.5 TTMS Y G Table I (cont.) Example ~ ~ Time (Minutes) No. Parts Stabilizers 3 6 9 12 15 13 1.35 MTMS W W W PY G 0.15 TTMS 14 1.2 MTMS W W PY Y Y 0.3 BaCO3 overbased complex 15 0.90 MTMS W W PY PY Y 0.30 BaCO3 overbased complex 0.30 TTMS 16 1.25 MTMS W W W W PY 0.10 BaCO3 overbased complex 0.15 BBMS 17 1.10 MTMS W W W W W 0.10 BaCO3 overbased complex

Claims (11)

Claims

1. A heat stabilizer composition for halogen-containing resins comprising a mixture of (a) from 99 to 20 weight percent of a sulfur-containing organotin compound having a -C-S n-S group; and (b) from 1 to 80 weight percent of a tin tetrakis(mercaptide) having four Sn-S bonds.

2. A composition according to claim 1, wherein said tin tetrakis(mercaptide) has the formula

where R6, R7, R8 and R9 are each alkyl, cycloalkyl, aryl or mixed alkyl-aryl radicals containing up to 22 carbon atoms, or such a radical substituted by halogen, -XH, -XR3, or

where R3 is alkyl, alkenyl, cycloalkyl, aryl or mixed alkyl-aryl of up to 20 carbon atoms, and X and Y are each independently oxygen or sulfur.

3. A composition according to claim 1 or 2, wherein said sulfur-containing organotin compound has the formula

where R1 is an alkyl, cycloalkyl, aryl or of up to 18 carbon atoms or such a mixed alkyl-aryl radical substituted by -CN, -OR3,

or --CO,R3 where R3 is as defined in claim 2; R2 is an alkyl, cycloalkyl, aryl, or mixed alkyl-aryl radical having 1-22 carbon atoms and optionally substituted by halogen, -XH, -XR3, or

where R3 is as defined in claim 5 and X and Y are each independently oxygen or sulfur; Z is 0, S, R1 or -SR2-SSn(R1) (SR2)b, where b is 1 or 2, and R1 and R2 are as defined above.

4. A composition according to claim 1,2 or 3 further comprising from 1 to 60 weight-percent, based on the weight of the composition, of an alkali or alkaline earth metal salt of a mercaptan or a mercapto acid.

5. A composition according to claim 4, wherein said alkali or alkaline earth metal salt is of the formula: M(SR4)n or

wherein: M is an alkali or alkaline earth metal, M1 is an alkaline earth metal, n is 1 when M is an alkali metal and n is 2 when M is an alkaline earth metal.

R4 is an alkyl, cycloalkyl, aryl or mixed alkyl-aryl radical of up to 22 carbon atoms or such a radical substituted by halogen, -XH, -XR3, or

where R3 is as defined in claim 2; X and Y are each independently oxygen or sulfur; R5 is a divaient hydrocarbon linking group having from 1 to 5 carbons optionally substituted by halogen, -XH, -XR3, or

where R3, X and Y are as defined in claim 2.

6. A composition according to claim 5, wherein the alkaline earth metal salt of mercaptan or mercapto acid is Ba(SCH2CO2C8H17)2, Ba(SCH2CH2CO2C8H17)2, Ba(SCH2CH202CC17H33) Ba(SCH2CH2O2CC17H35)2, Ca(SCH2CO2C8H17)2, Ca(SCH2CH2CO2C8H17)2, Ca(SCH2CH202CC1,H33)2 or Ca(SCH2CH2O2CC17H35)2.

7. A composition according to any one of the preceding claims further comprising from 1 to 60 weight percent, based on the weight of the composition, of an overbased organic complex of an alkali or alkaline earth metal base.

8. A composition according to claim 7, wherein said overbased organic complex is an overbased organic complex of an alkaline earth metal carbonate.

9. A composition according to claim 8, wherein the overbased organic complex is overbased with BaCO3 or CaCO3.

10. A composition according to any one of the preceding claims, wherein the tin tetrakis(mercaptide) is Sn(SCH2CO2C8H17)4 Sn(SCH2CH2CO2C8H17)4, Sn(SC12H25)4, Sn(SCH2CO2C8H17)3 (sc12H25)t Sn(SCH2CO2C8H17)2 (SC12H25)2'

Sn(SCH2CH2O2CC17H33)4, or Sn(SCH2CH2O2CC17H35)4.

11. A composition according to any one of the preceding claims, wherein the sulfur-containing organotin compound is CH3Sn(SCH2CO2C8H17)3, CH3Sn(SCH2CH2O2CC17H33)3, CH3Sn(SCH2CH2O2CC17H35)3, (C8H17)2Sn(SCH2CO2C8H17)2, (CH3)2Sn (SCH2CO2C8H17)2, C4H9Sn(SCH2CO2QH17)3, (CH3)2 Sn(SCH2CH2O2CC17H33)2, C8H17Sn(SCH2CO2C8H17)3, (CH3)2 Sn(SCH2CH2O2CC17H35)2, (C4H9)2 Sn(SC2H902CC17H33)2,

(r;4H9)2 Sn(SC2HgO2CC17H35)2, C4H9Sn(SC2H902CC17H33)3, or (C4Hg)2 Sn(SCH2CO2C8H17)2, QH9Sn(SC2H902CC17H35)3.

1 2. Halogenated resin containing as a heat stabilizer a composition as claimed in any one of the preceding claims.