DE1926949B2 - Heat-stabilized vinyl chloride polymer composition with a content of organotin compounds as heat stabilizers - Google Patents

Description

SR ³

20 O - C = O

or a polymer thereof or

RiSn

SR ³ C '

OR ^;

A-, i

and as a second stabilizer 0.1 to 10 parts by weight of a sulfur-free organotin compound of the formula

R ₃ ⁴ R ⁵ Sn
or

(R ₂ ⁵ SnOR ⁴ J ₂ O

contains, where R 'and R ^{2 are} each independently Ci_ ₂₀ -alkyl, cycloalkyl, aryl, alkaryl or aralkyl radicals, R ^{3 is} a methylene or ethylene radical, R ⁴ and R ^{5 are} from the same group as R. ¹ , with the proviso that R ⁴ and R ^{5 are} not identical when they are both bonded directly to a tin atom and a is 1 or 2.

The vinyl chloride polymer can be a homopolymer or a copolymer of vinyl chloride act with one or more copolymerizable ethylenically unsaturated compounds. Suitable Comonomers are acrylic acid and derivatives thereof, such as. B. ethyl acrylate and acrylonitrile; Vinyl monomers, such as B. styrene and vinyl acetate; Maleates, such as maleic acid, maleic anhydride and maleate ester. For the sake of convenience, the term vinyl chloride polymer will be used in the following.

The vinyl chloride polymers can be either hard or soft. When using hard polymers then they can be impact modifiers, pigments. Contain fillers, lubricants, etc. If soft polymers are used, then they can contain primary and secondary plasticizers, pigments, fillers, lubricants, etc. A friend The plasticizer is dioctyl phthalate. A well-known lubricant is stearic acid.

The first stabilizer is an organotin compound in which the remainder of a mercaptocarboxylic acid or the remainder of a Mcrciiptocarbonsäureester is contained.

In the presence of a residue of a mercaptocarboxylic acid, not only cyclic but also polymeric forms are conceivable.
Typical preferred first stabilizers are:

Dibutyltin-jS-mercapto-propionate

(including the polymers thereof)
Dioctyltin-ji-mercapto-propionate

(including the polymers thereof)
Dibutyltin bisfisooctyl mercaptoacetate)
Dioctyltin bis (isooctyl mercaptoacetate)
Dicyclohexyltin-bis (isooctyl-mercaptoacetai)
Dimethyltin bisiisooctyl mercaptoacetate)
Diphenyltin bisfisooctyl mercaptoacetate)
Dibutyltin bisilauryl mercaptoacetate)
Dibutyltin-bisibenzyl-mercaptoacetate)
Dibutyltin bis (cyclohexyl mercaptoacetate).

It is particularly preferred

Dibutyltin bis (isooctyl mercaptoacetate).
Preferred second stabilizers are:

Dibutyl diphenyl tin

Triphenyl-bulyl-tin

Dimethyl diphenyl tin

Dicyclohexyl diphenyl tin

Bis (dibutyl-lauryloxy tin) oxide

Bis (dibutyl-ctecyloxy tin) oxide

It is particularly preferred
Dibutyl diphenyl tin.

The stabilized vinyl chloride polymers of the invention can be done by techniques such as milling, dry blending, or blending in a Banbury mixer be prepared by another well-known mixing method. A mixing process that is special is useful, consists in the preparation of a stabilizer composition, the first and the contains second stabilizer and in a thorough blending into the vinyl chloride polymer. Which mixing method whichever is used, it is desirable in either case to use the first stabilizer and the second Carefully distribute the stabilizer in the vinyl chloride polymer.

The invention is explained in more detail with reference to the following examples. In the examples, all parts are in Expressed by weight unless otherwise specified.

The selected compositions were carefully mixed by adding the polyvinyl chloride to a Two roller differential mill was applied, which was heated with oil to a temperature of 175 ° C. At the same time, the specified amount of the first and the second stabilizer was added. The mixture was rolled for about 5 minutes. An endless band of composition formed around one of the rolls. This tape was cut open and the composition was taken off the hot roll as a continuous one Layer removed. This material was made into squares measuring 2.54 cm × 2.54 cm for the Heat stability tests cut out.

For the thermal stability test, the squares were placed in an air oven, which was adjusted so that a temperature was maintained from 205 ⁰ C. Samples of each composition were removed from the oven at 15 minute intervals and visually rated for color change and degradation according to the following scale.

7 - clear, water-white

6 - just white

5 - lightest degree of yellowing

4 - moderate yellowing

3 - deep yellow-brown color

2 - deep brown color

1 - dark brown to black color.

The time, in minutes, it took to reach a value of 3 or less was used as Thermal stability value taken.

example 1

In this example, a hard vinyl chloride polymer was used which had a specific gravity of 1.40, a Shore Durometer>"D" hardness of 80, and a final tensile strength of approximately 490 kg / cm ² and that was sold under the trademark Geon 103 EP is distributed.

In this example, 100 parts were made of vinyl chloride polymer tested without the addition of a stabilizer and taken as a comparison (experiment A). In another Experiment (experiment B) was only 3.0 parts of the first stabilizer dibutyltin-bisiisooctyl-mercaptoacetate) available. In a third experiment (experiment C) only 3.0 parts of the second stabilizer were dibutyl-diphenyltin available. In an experiment according to the invention (experiment D) 2.0 parts were dibutyl-diphenyl-tin and 1.0 part dibutyltin bisiisooctyl mercaptoacetate) present. So a total of 3.0 parts stabilizer.

The results of the thermal stability tests are summarized in Table I below:

Table I.

40

45 From Table 1 it can be seen that Experiment D according to the invention gives the best results. The mixture D according to the invention is distinguished by particularly low costs, a low sulfur content and a low odor during grinding.

Example 2

This example was run on a different vinyl chloride polymer, a polymer having a specific gravity of 1.40, a Shore Durometer "D" hardness of 80, and a final tensile strength of approximately 490 kg / cm ² and under the trademark Diamond - 450 is sold. These resin compositions contain 0.1 part of 2,6-di-tert-butylcresol. The oven temperature was maintained at 175 ° C. The sample was made with the indicated ingredients and the thermal stability value and the heat after milling were as indicated below.

attempt Thermal stability value Color according to in minutes grinding A. no heat stability, 1 stuck after 1 min the mill B. 40 6th C. 5 4th D. 40 7th

Try

Vinyl chloride polymer 100

Di-r-butyltin-bisfiso-octy ¹ -

mercaptoacetate 1.0

fi bis (dibutyl-lauryloxy tin) oxide 0.5

Heat stability value 60 min

■ color according to di. m grinding 7

It can be seen that the thermal stability value of the product of the invention is exceptional.

| v; The color after grinding is also very high.

Claims (1)

Claim: Heat-stabilized vinyl chloride polymer composition containing a sulfur-containing organotin compound as a heat stabilizer, thereby characterized in that they are 0.1 to 10 parts by weight per 100 parts by weight of polymer a sulfur-containing organotin compound as the first stabilizer of the formula S -R ³ O-C = O or a polymer thereof or RiSn SR ³ C OR ² 25th and as a second stabilizer 0.1 to 10 parts by weight of a sulfur-free organotin compound of formula R ₂ ⁴ R ₂ ⁵ Sn, R ₃ ⁴ R ⁵ Sn
or contains, where R ¹ and R ^{2 are} each independently r> of one another for Ci_ ₂₀ -alkyl, cycloalkyl, aryl, alkaryl or aralkyl radicals, R ^{3 stands} for a methylene or ethylene radical, R ⁴ and R ⁵ from the same group are selected as R ¹ , with the proviso that R ⁴ and R ^{5 are} not identical when they are both bonded directly to a tin atom and a is 1 or 2. 45 It is well known that vinyl chloride polymers and also copolymers of vinyl chloride with others Monomers degrade if they are exposed to heat for a long period of time, which results in a Darkening of the resin and an increase in brittleness. The lack of thermal stability of Vinyl chloride polymers make themselves especially good when mixed with pigments, plasticizers, lubricants etc. noticeable. When such additives are incorporated, the mixtures are brought to temperatures in for 5 to 30 minutes around 175 ° C. As heat stabilizers in vinyl chloride polymers, sulfur-containing organotin compounds, such as. B. organotin mercaptides and derivatives of wi mercaptocarboxylic acids, as well as sulfur-containing esters, e.g. B. Di-n-butyltin-S.S'-bisiisooctyl-mercaptoacetate) is used. However, these compounds are expensive and add significantly to the cost of the stabilized resins. In addition, these compounds can impart an offensive odor to the M resin composition when used in concentrations that give high heat stabilization. It has now been found that some of the sulfur-containing organotin compounds through Sulfur-free organotin compounds, which, when used alone, can be substituted for Vinyl chloride polymers are relatively poor heat stabilizers. These sulfur-free organotin compounds are much cheaper than the more effective sulfur-containing organotin compounds. The invention therefore relates to a heat-stabilized one Vinyl chloride polymer containing a sulfur-containing organotin compound as a heat stabilizer, which is characterized in that it contains 0.1 to 10 parts by weight per 100 parts by weight of polymer a sulfur-containing organotin compound as the first stabilizer of the formula