DE4300059C1 - Use of monosalicylates of divalent metals to stabilize chlorine-containing polymers - Google Patents

Description

Chlorine-containing polymers, such as polyvinyl chloride (PVC), are listed under Exposure to heat and / or light decomposes what to unwanted discoloration and impairment of the Performance characteristics leads. To these damaging influences too reduce, stabilizers are added to the polymers. In the event of the polymers of vinyl chloride, especially PVC, these stabilizers contain mostly organic and inorganic compounds of lead. This is especially true for Applications with high long-term requirements regarding Weather and heat stability, such as window and Roller shutter profiles as well as cables, where mainly basic ones Lead salts, such as basic lead sulfate or basic lead phosphite, be used. In some areas, these are Lead compounds with e.g. B. Barium and cadmium metal soaps combined to highly effective stabilizers.

Since lead, barium and cadmium are toxic, has been around for a long time tries to substitute them. For this purpose, a Variety of combinations suggested, mostly based on Compounds of the metals zinc, magnesium, calcium and / or Aluminum. The calcium / zinc stabilizers, however, must be included Co-stabilizers are combined to make them Plastic parts to the required properties to lend. So far, however, Calcium / zinc stabilizers to develop which are related to the Long-term stability provides values that are comparable to those of lead or Lead / barium / cadmium stabilizers.

From EP-A 0 022 047, example 32, it is known to also use calcium salicylate in a stabilizer mixture for PVC composed of zinc stearate, sorbitol and the thioglycolate of bishydroxymethyl-1,4-cyclohexane. Unless otherwise stated, this calcium salicylate is a common calcium salicylate of the formula Ca (salicylate) ₂ , ie calcium to salicylate is contained in a molar ratio of 1: 2 in this compound. Even these complicated stabilizer mixtures do not meet the desired requirements.

The present invention has for its object the above mentioned disadvantages of the prior art through the use to overcome previously unused stabilizers.

This object is achieved according to the invention by using at least one optionally substituted salicylate at least one divalent metal, where salicylate and metal present in a molar ratio of about 1: 1 for stabilization chlorine-containing polymers against degradation by heat and light.

The salicylates of divalent metals used according to the invention are in contrast to the usual salicylates, which are two Contain salicylate residues on a metal cation, in a molar ratio from 1: 1 before, d. i.e., comes on a divalent metal cation just a salicylate residue.

In the salicylates used according to the invention divalent So metals are monosalicylates - in contrast to the usual disalicylates.

It has surprisingly been found that the Special metal salicylates used according to the invention particularly good for stabilizing chlorine-containing polymers against degradation through heat and light.

From US-A 3 438 934 it is known to stabilize fluoropolymers with a non-acidic salicylic acid salt from the group Li, Na, K, Mg, Ca, Sr, Ba, Pb, Zn, Sn, Al, Bi and NH ₄ . These are also the customary salicylates, in which there is one salicylate residue on a monovalent cation, two salicylate residues on a divalent cation and three salicylate residues on a trivalent cation, that is, the salicylic acid salts used in this prior art differ from those metal salicylates used in the present invention. Furthermore, it is known to the person skilled in the art that fluoropolymers behave completely differently from chlorine-containing polymers in production, processing, usage properties and stabilization with respect to degradation by heat and light.

The metal salicylates used according to the invention can according to known methods, cf. e.g. B. Babko, A.K. and Ertushenko, N.P., Ukr. Khim. Zh 1969, pp. 295-302. The Metal salicylates used according to the invention are at 105 ° C probably in the form I before:

After dewatering, they are probably in Form II at 170 ° C in front:

The metal salicylates used according to the invention can for example by reacting salicylic acid with the corresponding metal hydroxide in a molar ratio of 1: 1 become. The acid component used for the reaction can it is salicylic acid (2-hydroxybenzoic acid) or an in 3-, 4-, 5- or 6-position substituted salicylic acid; the substituents can be selected, for example, from the group hydroxyl, Alkyl and aryl may be selected, the substituents being further functional groups such as oxygen, sulfur and nitrogen, can contain.

The metal salicylates used in the invention contained metals can, for example, alkaline earth metals or  Be zinc, with magnesium, calcium, strontium and zinc, and especially calcium and zinc are preferred; it can too Combinations of two or more of these divalent metals be used.

The metal salicylates used according to the invention are added to the stabilizing chlorine-containing polymer in general in Amounts of 0.5 to 5 parts by weight per 100 parts by weight chlorine-containing polymer added.

The metal salicylates used according to the invention can be used for better incorporation into the chlorine-containing to be stabilized Polymer be surface treated.

The metal salicylates used according to the invention can be used for Stabilization of chlorine-containing polymers, especially for Stabilization of polymers of vinyl chloride and especially used to stabilize PVC. Furthermore, the Metal salicylates used according to the invention in Graft polymers or blends consisting of different polymers.

The chlorine-containing polymers to be stabilized can be used either the bulk, suspension and emulsion polymerization processes are produced, as well as copolymers of vinyl chloride e.g. B. vinyl acetate, vinylidene chloride, vinyl ether, acrylonitrile, Acrylic acid ester, maleic acid, mono- or di-ester or olefins his.

The metal salicylates used according to the invention can be combined with other heat, light and anti-aging agents. Such compounds, which are usually used as additives e.g. B. used for PVC, z. B. be: Compounds of metals such as alkaline earth metals and / or zinc, e.g. B. Mono carboxylates of C ₈ - to C ₃₀ carboxylic acids, which may also contain basic components; Oxides or hydroxides of metals, e.g. As calcium hydroxide or zinc oxide, hydrotalkites, basic Ca / Al compounds, zeolites or tin-containing stabilizers; organic stabilizers such as 1,3-diketones (e.g. dibenzoylmethane) or their metal salts, polyols (e.g. dipentaerythritol), isocyanurates (tris-hydroxyethyl-isocyanurate) dihydropyridines and phosphites can also be used.

In the polymers containing the metal salicylates used according to the invention, additives usually used, such as fillers (e.g. chalk, anhydrite), pigments (e.g. TiO ₂ and / or zinc sulfide), flame retardants (e.g. magnesium hydroxide, aluminum hydroxide and / or antimony trioxide) reinforcing agents (e.g. glass fibers and / or talc) and plasticizers (e.g. di-2-ethylhexyl phthalate and / or di isodecyl phthalate) may be included.

To adjust the rheological requirements, the chlorine-containing polymers lubricants, such as paraffin waxes, low molecular weight polyolefins, ester lubricants from mono- or polyvalent alcohols and mono- or dicarboxylic acids or Amide waxes are added.

Furthermore, the chlorine-containing polymers can contain other additives, such as e.g. B. antioxidants, sterically hindered amines, optical Brighteners, epoxies and sulfur-containing compounds, in particular the sulfur-containing organic compounds used for Manufacture of tin-containing stabilizers are used added to desired properties of the chlorine-containing To achieve or reinforce polymers.

The examples illustrate the invention. Parts and percentages unless otherwise stated, refer to the Weight.

The compositions labeled "B" are compositions stabilized according to the invention, while with "V" designated compositions not according to the invention are stabilized comparative compositions.  

The compositions given in the tables were based on a two-roll mill in counter-rotation (Collin roll) at 180 ° C rolled. After 5 minutes, the rolled skin was removed and its HCl stability determined in the Congo red test. The fur was in Cut strips, stored in a Mathis oven at 200 ° C were. The initial color and the Gradient checked.

Since the calcium / zinc stabilizers, in contrast to basic lead compounds, have no white pigmenting effect, 0.5 parts of TiO _{2 are} added to the calcium / zinc stabilizers in order to make the initial color and color retention comparable with the lead-containing comparative example.

Table 1

Congo red test

Table 2

color gradient

Table 3

Congo red test

Table 4

color gradient

Table 5

Congo red test

Below is a possible production of Calcium monosalicylate to be used according to the invention:

A 10% by weight aqueous Ca (OH) ₂ suspension (1 mol Ca (OH) ₂ ) is heated to 50 ° C. Then 1 mol of salicylic acid is added with stirring so slowly that the pH of the suspension does not fall below 11.5. The reaction product is filtered off and dried at 105 ° C. The product can be dewatered by further drying at about 170 ° C. The product dried to 105 ° C is presumably Form I given above and the product dried to 170 ° C is Form II given above.

Claims (4)

1. Use of at least one optionally substituted Salicylate of at least one divalent metal, where Salicylate and metal are present in a molar ratio of about 1: 1, to stabilize chlorine-containing polymers against degradation through warmth and light. 2. Use according to claim 1, wherein to 100 parts by weight chlorine-containing polymer 0.1 to 5 parts by weight of metal salicylate be used. 3. Use according to claim 1 and / or 2 for the stabilization of Vinyl chloride polymers, especially polyvinyl chloride. 4. Use according to any one of claims 1 to 3, wherein it is the divalent metals contained in the metal salicylate is alkaline earth metal or zinc.