DE2148774A1 - Stabilizers for vinyl chloride resins - Google Patents

Description

Dr. A. ULLRICH Dr. T. ULIRICH

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INTERSTAB LIMITED, Stockpit Road, Kirkby Industrial Estate, Liverpool L 33 7TH, Great Britain

Stabilizers for vinyl chloride resins

The polymers and copolymers of vinyl chloride are thermoplastics that contain labile chlorine atoms that are resistant to Heat are unstable. Therefore, when heated during normal manufacturing processes, such polymers tend to For example, when processing on the calender and during extrusion, it can be released fairly quickly of hydrogen chloride gas, accompanied by a rapid darkening of the resin to decompose. This particular characteristic, if not overcome, limits its value these polymers for the production of transparent, colorless or lightly colored articles. happily the problem can be reduced to an acceptable ratio by adding small amounts of additives.

Many compounds have been suggested and are believed to be satisfactory stabilizers for PVC in the first place the organotin compounds. The dialkyltin compounds are of particular value, especially in Combination with a mercaptide anion. Typical examples of such compounds are dibutyltin-bis-lauryl mercaptide and dibutyl tin bis-isooctyl thioglycolate. From these two

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the latter connection is the stronger one and it has been more widespread in industry for several years pleased. In recent years, however, there is a tendency to reduce the production quantities of certain pieces of equipment to increase, resulting in additional frictional heat within the PVC joint and on the other hand to a limitation in terms of the use of dibutyltin bis-isooctylthioglycolate as a general purpose stabilizer. Many attempts have been made to improve performance this product by adding small amounts of other known additional stabilizers, such as antioxidants, organic Phosphites and epoxy oils. All of these offer little or no improvements in performance, caused by the basic stabilizer. The subject of the invention is "a new stabilizer to create derived from a dialkyltin mercapto compound, and a corresponding compound that shows significantly improved performance over the base dialkyltin compound.

According to the invention, a stabilizing composition created as stabilizing ingredients

a) a compound of the formula

R ₂ Sn (Z) ₂
and

b) a smaller proportion of a compound of the formula

R Sn (Z),

Contains, in which R is an alkyl radical of 1 to 18 carbon atoms and -Z -SfCH ₂ J'COOR ¹ , -OCOCH = CHCOOr ¹ , -OCOR ¹ or -SR ¹ , η 1 or 2 and R ^{1 is} an alkyl radical of 1 to 18 Represent carbon atoms.

Among the substances encompassed by the above formulas are dibutyltin, monobutyltin, Dioctyl tin and monooctyl tin derivatives of:

Methyl, butyl, isooctyl, 2-ethylhexyl, n-decyl, Lauryl and stearyl thioglycolates and

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jä-mercaptopropionate;

Hexyl, n-decyl, isodecyl, n-dodecyl, tert. Dodecyl and stearyl mercaptan;

Vinegar, butter, isooctyl, 2-ethylhexyl, Nonanyl, lauric, and stearic acids;

Monomethyl, monobutyl, monoisooctyl, mono-2-ethylhexyl, Mono.lauryl and monostearylraaleates.

It is surprising that, although monoalkyltin trithioglycolate esters have inferior stabilization properties compared to the corresponding dibutyltin compounds, mixtures of the two exhibit a significant axial effect which gives the mixture excellent enhanced stabilization properties. Improved results can be achieved with no more than 5 % addition of the monoalkyltin compound to the dialkyl compound. However, the optimum effect appears to be achieved with an addition of almost 20 % . Above this limit, a so-called plateau effect between 20 % and 50 % appears to be obtained and no significant improvement in properties is observed at the higher values.

The improvements achieved can easily be observed from the following examples in which all parts are given as parts by weight.

Examples

) PVC 100
Epoxy oil 0.5

Ester plasticizers 1,2
Stabilizer 2.0

The above composition was made on a two-roll laboratory mill mixed together in 5 minutes at 155 ° C until complete homogenization

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was achieved. The resulting sheet was then removed from the roller to a thickness of 0.05 inch = 1.27 mm and samples were heated in an air flow oven at 185 ° C. and removed at 10 minute intervals. These samples were visually examined for the rate of color development and this was taken as a value of the rate of decomposition of the PVC compound. The results of this type of experiment are easier to determine by visual observation, but the experiment indicated below was used to convey the observed effect by referring to the table which shows the time in which the samples develop particular colorations. In this example, the salts used consisted of the dibutyl tin and monobutyl tin salts of isooctyl thioglycolate. They were mixed together at various concentrations and 2 parts by weight per 100 parts of the mixture were used in each experiment. The results clearly show the improved effect obtained at low levels and the significantly improved effect obtained when 20 % of the monobutyltin salt was incorporated into the corresponding dibutyltin salt.

Parts per 100 parts resin Monobutyl
tin salts Time in minutes up to one
certain coloring Amber
Colours black Dibutyl tin
salts 0
0.1
0.2
0.4
0.6
0.8
2.0 weak
yellow 70
80
80
85
85
85
70 80
90
90
90
90
90
80 2.0
1.9
1.8
1.6
1.4
1.2 '30
40
60
70
70
70
50

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2.) Experiments were carried out as in Example 1, but using the monobutyltin salt of isooctyl-ßmercaptopropionate.

Parts per 100 parts resin Monobutyl tin
tri- (isooctyl-
ß-mercaptopro-
pioneer) Time in minutes to a '
certain coloring Amber
Colours black Dibutyl tin
bis- (isooetyl-
thioglycolate) 0
0.1
0.2
0.3
0.4
0.6
0.8 weak
yellow 70
80
80
90
90
90
80 80
90
90
100
100
100
90 2.0
1.9
1.8
1.7
1.6
1.4
1.2 30th
50
60
70
70
70
70

3.) PVC layers were made in the manner described in Example 1, but in this case the dioctyltin and monooctyl tin salts of isooctyl thioglycolate are used. The results obtained here confirm the advantage of Use of such mixtures versus the use of the individual salts alone.

Parts per 100 parts resin Monooctyl
tin salts Time in minutes up to one
certain coloring Amber
Colours black Dioctyl tin
salts 0.1
0.2
0.4
2.0 weak '
yellow 60
70
70
70
55 70
80
80
80
60 2.0
1.9
1.8
1.6 VJl ON ON VJl VJl
ο σ ο ο ο

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4.) Similar attempts have been made using the following compounds as monoalkyl tin compounds were used:

Parts per 100 parts resin Monobutyl tin
trllaurat Time in minutes up to
certain coloring Amber
Colours one Dibutyltin
bis- (isooctyl-
thioglycolate 0 weak
yellow 70 black
i 2.0 0.2 30th 80 i i, 8 0.4 70 75 1.6 0.6 60 70 1.4 Monobutyl tin
tri- (lauryl-
mercaptid) 6o 0.2 80 1.8 0.4 70 75 1.6 0.6 70 70 1.4 Monobutyl tin
tri- (2-ethyl-
hexyl maleate) 60 0.2 80 1.8 0.4 70 8o 1.6 0.6 70 75 1.4 60 80 90 80 80 90 90 80 90 90 90

The monoalkyl tin compounds used according to the invention are monomeric compounds that can be obtained by reacting 1 mole of alkyltin acid with almost 3 moles, more precisely over 2.5 up to 3.5 moles Mercapto acid ester, mercaptan, carboxylic acid or dicarboxylic acid monoester, receives.

The following examples illustrate the preparation of the monoalkyl sense compounds.

5.) Octyltin tri-isooctylthioglycolate)

It was isooctyl thioglycolate (612 g = 3 mol) to 70 to 80 ° C heated and octyltin acid (264.7 g = 1 mol) added with stirring. The temperature was raised under a light stick

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Stream for removing the water of reaction (36 g = 2 moles) was increased to 110 ° C and the product was filtered to give octyltin tri- (isooctylthloglycolate) (840.7 g = 1 mole).

6.) Butyltin ^ tri-Cisooctylthioglycolate

It was isooctylthloglycolate (612 g = 3 mol) to 70 bis 80 ° C heated and butyltin acid (208.7 g = 1 mol) under Stir added. The temperature was increased under a gentle stream of nitrogen to remove the water of reaction (36 g = 2 mol) increased to 110 ° C and the product was filtered and gave dibutyltin tri- (isooctylthioglycolate) (784.7 = χ MoI).

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Claims (8)

Claims 1.) Stabilizing composition for use in vinyl chloride resins, characterized in that they are used as stabilizing ingredients a) a compound of the formula R ₂ Sn (Z) ₂
and b) a smaller proportion of a compound of the formula R Sn (Z), Contains, in which R is an alkyl radical of 1 to 18 carbon atoms and -Z is -SfCH _p ) COOR ¹ , -OCOCH = CHCOOr ¹ , -OCOR ¹ or -SR ¹ , η 1 or 2 and R ^{1 represent} an alkyl radical of 1 to 18 carbon atoms. 2.) Composition according to claim 1, characterized in that it contains about 5 to 40 wt -% monoalkyltin compound contains.. 3.) Composition according to claim 1 or 2, characterized in that the alkyl radicals of the dialkyl tin compound Octylradikale butyl or represent. k.) Composition according to claim 1, 2 or 3, characterized in that the alkyl radical of the monoalkyltin group is a butyl or octyl radical. 5.) Composition according to claim 1, 2 or j5, characterized in that the monoalkyltin compound monobutyl- or monooctyltin-tri-fbutylthioglycolate, (isooctylthioglycolate), (isooctyl-ß-mercaptopropionate), (laurate ^, (lauryl mercaptide) or (2- Ethylhexyl maleate). 209815/1666 2U8774 6.) Process for stabilizing vinyl chloride resins, characterized in that a composition according to Claims 1 to 5 is incorporated into the resins in the amounts required for stabilization. 7 ·) Vinyl chloride resin, characterized in that it is stabilized against the action of heat with the aid of a stabilizing composition according to Claims 1 to 5. 8.) Process for the preparation of monomeric monoalkyltin compounds, characterized in that 1 mol of monoalkyltin acid is heated and brought to reaction with almost 5 mol of a mercapto acid ester, mercaptan, carboxylic acid or dicarboxylic acid monoester. 209815/1666