WO2004087801A1 - Use of compositions comprising basic metal oxides and/or metal hydroxides for stabilizing halogen-containing organic plastic materials - Google Patents

Abstract

Disclosed are compositions containing (i) at least one additive that is sensitive to alkaline compounds, and (ii) basic metal oxides and/or metal hydroxides which are embedded into an enveloping matrix made of hydrocarbons. Said compositions are suitable for stabilizing halogen-containing organic plastic materials, particularly PVC, against thermal and/or photochemical decomposition and are especially stable during storage.

Description

"Use of compositions containing basic metal oxides and / or hydroxides for stabilizing halogen-containing organic plastics"

Field of the Invention

The invention relates to the use of compositions containing basic metal oxides and / or hydroxides, which are embedded in an enveloping matrix of hydrocarbons, for stabilizing halogen-containing organic plastics.

State of the art

Halogen-containing plastics or molding materials made from them are known to have a tendency to degrade or decompose if they are exposed to thermal stress or come into contact with high-energy radiation, for example ultraviolet light.

Metal-containing stabilizers based on Pb, Ba, Cd, Sn, Ca and Zn are mostly used to stabilize PVC during processing. As early as 1940, harris derivatives such as Diphenylthiourea proposed to stabilize PVC. These compounds are mostly used in combination with metal-containing stabilizers, since they alone generally do not result in adequate long-term stabilization.

One way to extend long-term stability is to add basic substances such as zeolites, soda or metal hydroxides. Strong bases such as calcium hydroxide are particularly effective here, but have the disadvantage that they can react with metal soaps and esters present in the stabilizer. This leads to uncontrolled chemical reactions in the manufacture of stabilizers and in processing Production. At the same time, these mixtures can absorb carbon dioxide from the air, which leads to poor shelf life and poor stabilization properties.

DESCRIPTION OF THE INVENTION The object of the invention was to provide compositions for stabilizing halogen-containing organic plastics, in particular PVC, against thermal and / or photochemical degradation, which contain basic metal oxides and / or hydroxides on the one hand and components which are sensitive with regard to alkaline compounds on the other hand are, the basic metal oxides and / or hydroxides should be present in these compositions in a form which brings about the stability of the compounds sensitive to alkaline compounds. In this context, sensitivity with regard to alkaline compounds is understood to mean that the corresponding compounds are able to react with alkaline compounds, which include, for example, basic metal oxides and metal hydroxides. Another task was that the basic form of the basic metal oxides and / or hydroxides should have the property: that the basic metal oxides and / or hydroxides be effective against deactivation by absorption of carbon dioxide and moisture when stored before use as PVC additives should be protected from the air.

The invention relates to the use of basic metal oxides and / or hydroxides as an additive for halogen-containing organic plastics, the basic metal oxides and / or hydroxides being embedded in an enveloping matrix of hydrocarbons

Basic metal oxides and / or hydroxides which are embedded in an enveloping matrix of hydrocarbons are understood to mean that the basic metal oxides and / or hydroxides are embedded in a matrix of hydrocarbons are. In this way, the particles of the basic metal oxides and / or hydroxides, which could react with substances sensitive to basic compounds, are encased by a type of protective layer, so that contact of the encased particles with the above-mentioned sensitive substances remains without consequences in the desired sense.

Basic metal oxides and / or hydroxides, which are used in the context of stabilizing PVC against thermal or photochemical degradation, are known to the person skilled in the art. In this regard, the type of basic metal oxides and / or hydroxides that can be used in the context of the present invention is not subject to any restrictions.

Examples of suitable basic metal oxides and / or hydroxides are sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide and aluminum hydroxide, furthermore basic oxides of calcium, magnesium, strontium, barium and aluminum.

The type of hydrocarbons that can be used in the context of the invention is not critical per se. However, the hydrocarbons should meet the condition of being solid or at least wax-like at 20 ° C. Accordingly, hydrocarbons liquid at 20 ° C are not suitable as matrix materials.

Examples of suitable hydrocarbons are linear or branched paraffins, cyclic or aromatic hydrocarbons, polyethylene waxes and polypropylene waxes.

The basic metal oxides and / or hydroxides embedded in a hydrocarbon matrix can be produced, for example, by simply stirring the basic metal oxides and / or hydroxides into molten hydrocarbons. The melt can then be made up using customary methods. The basic metal oxides and / or hydroxides modified in this way can be used as such or in combination with other customary additives in PVC stabilizer compositions.

The weight ratio of the hydrocarbon matrix and the basic metal oxides and / or hydroxides embedded therein is not subject to any particular restrictions. However, it must be ensured that the hydrocarbon is present in an amount which ensures adequate coating of the basic metal oxides and / or hydroxides. The weight ratio of hydrocarbon matrix and basic metal oxides and / or hydroxides embedded therein is preferably adjusted to values in the range from 1-70% by weight.

Another object of the invention is the use of compositions containing basic metal oxides and / or hydroxides, which are embedded in an enveloping matrix of hydrocarbons, for stabilizing halogen-containing organic plastics, in particular PVC, against thermal and or photochemical degradation. The advantage of the invention is all the more evident the more the compositions contain alkali-sensitive compounds.

When stabilizing halogen-containing organic plastics, the basic metal oxides and / or hydroxides to be used according to the invention embedded in a hydrocarbon matrix are used in an amount of 0.001 to 5 phr, preferably 0.01 to 2 phr and in particular 0.01 to 0.5 phr used, it should be noted that the amount relates only to the basic metal oxides and / or hydroxides and the amount of the hydrocarbon matrix is not taken into account. Example: 5 g of calcium hydroxide powder is stirred into 10 g of a melted paraffin, stirred well and then allowed to cool. Matrix-embedded cylcium hydroxide is obtained, but the total amount of 15 g contains only 5 g of calcium hydroxide. Now put the total amount of 15 g one Amount of 100 PVC, the amount of calcium hydroxide in the PVC thus equipped is 5 phr.

As is known, the term phr ("parts per hundred resin") familiar to the person skilled in the art indicates how many parts by weight of the component are present in the plastic, based on 100 parts by weight of plastic.

Another object of the invention are PVC stabilizer compositions containing

(i) at least one additive sensitive to alkaline compounds and (ii) basic metal oxides and / or hydroxides, which are embedded in an enveloping matrix of hydrocarbons.

In one embodiment, the PVC stabilizer compositions according to the invention further contain one or more plastic additives which are selected from the group of the following compounds: cyanoacetylureas, dimethylaminouracil, antistatic agents, zeolites, cationic layer compounds, CHAP compounds, katoites, glycidyl compounds, beta Diketones and beta-keto esters, dihydropyridines and polydihydropyridines, polyols and polyol derivatives, sterically hindered amines (tetraalkylpiperidine compounds), alkali alumocarbonates (Dawsonite), alkali and alkaline earth metal compounds, antioxidants, release agents and or lubricants, plasticizers, pigments, thiophosphates and phosphites, phosphites, phosphites , Mercaptocarboxylic acid esters, epoxidized fatty acid esters, UV absorbers and light stabilizers, blowing agents, urea, metal soaps, perchlorates, trifluoromethanesulfonates. The plastic additives mentioned are known to the person skilled in the art and have been described many times in the literature. In this regard, reference is made, for example, to the applicant's WO-A-03/004558. The halogen-containing organic plastics which are to be stabilized with the stabilizer compositions according to the invention are, in particular, chlorine-containing polymers or their recyclates. Examples of such chlorine-containing polymers or their recyclates to be stabilized are: polymers of vinyl chloride, vinyl resins containing vinyl chloride units in their structure, such as copolymers of vinyl chloride and vinyl esters of aliphatic acids, in particular vinyl acetate, copolymers of vinyl chloride with esters of acrylic and methacrylic acid and with acrylonitrile Copolymers of vinyl chloride with diene compounds and unsaturated dicarboxylic acids or their anhydrides, such as copolymers of vinyl chloride with diethyl maleate, diethyl fumarate or maleic anhydride, post-chlorinated polymers and copolymers of vinyl chloride, copolymers of vinyl chloride and vinylidene chloride with unsaturated aldehydes, ketones and others, such as acrolein, such as acrolein , Vinyl methyl ether, vinyl isobutyl ether and the like; Polymers of vinylidene chloride and copolymers thereof with vinyl chloride and other polymerizable compounds; Polymers of vinyl chloroacetate and dichlorodivinyl ether; chlorinated polymers of vinyl acetate, chlorinated polymeric esters of acrylic acid and alpha-substituted acrylic acid; Polymers of chlorinated styrenes, for example dichlorostyrene; chlorinated polymers of ethylene; Polymers and post-chlorinated polymers of chlorobutadiene and their copolymers with vinyl chloride; and mixtures of the polymers mentioned with one another or with other polymerizable compounds.

Also included are the graft polymers of PVC with EVA, ABS and MBS. Preferred substrates are also mixtures of the homopolymers and copolymers mentioned above, in particular vinyl chloride homopolymers, with other thermoplastic or / and elastomeric polymers, in particular blends with ABS, MBS, NBR, SAN, EVA, CPE, MBAS, PMA, PMMA, EPDM and polylactones.

Suspension and bulk polymers and emulsion polymers are also preferred. Polyvinyl chloride is particularly preferred as the chlorine-containing polymer, in particular suspension polymer and bulk polymer.

In the context of this invention, PVC is also understood to mean copolymers or graft polymers of PVC with polymerizable compounds such as acrylonitrile, vinyl acetate or ABS, which may be suspension, bulk or emulsion polymers. PVC homopolymer is also preferred in combination with polyacrylates.

Furthermore, recycled chlorine-containing polymers are also possible, these being the polymers described in more detail above, which have been damaged by processing, use or storage. PVC recyclate is particularly preferred. The recyclates may also contain small amounts of foreign substances, such as paper, pigments, adhesives, which are often difficult to remove. These foreign substances can also come from contact with various substances during use or refurbishment, such as fuel residues, paint components, metal traces and initiator residues.

Example

About the substances used

Deawax LS 567 = paraffin (Dea-Oil)

PVC = Evipol SH 6830 (EVC)

Loxiol G 22 = paraffin (Cognis)

Polyethylene wax = type PE 520 (Clariant)

Oxidized polyethylene wax = type AC 629A (Honeywell)

Sodium perchlorate (Fluka)

Chalk = Omyalite 95 T (Omya)

Example 1 (Bl)

(Mixture according to the invention) 164.4 g of Deawax LS 567 were melted in a beaker and heated to 80.degree. 32.9 g of calcium hydroxide were added to this mixture with stirring and the mixture was homogenized for about 10 minutes. The melt was poured into a metal pan to cool. The cooled material was finely ground on a metal grater. The material is calcium hydroxide embedded in an enveloping matrix of hydrocarbons (here Deawachs LS 567).

The material obtained is referred to in Table 1 (see below) as a component according to B1.

Example 2 (VI)

(for comparison) 164.4 g of solid Deawax LS 567 and 32.9 g of solid calcium hydroxide were dry mixed in a beaker.

The material obtained is referred to in Table 1 (see below) as a component according to VI. applications

(Examples B3-bis-B5)

In Table 1 below, the individual formulation components of the examined test formulations were given, on the one hand, and the determined test results, on the other hand. The respective numbers of the examples are given in the first line of the table. The proportions of the individual components are given in phr; phr means "part per hundred resin" and indicates how many parts by weight of the respective component are present in PVC after adding the composition - based on 100 parts by weight of PVC. Accordingly, the recipes each contain 100 parts of PVC (Evipol SH 6830).

Example 5 (B5) is according to the invention. Examples 3 and 4 (B3 and B4) serve this

Comparison.

It should be noted that in example 3, the production of the flat strips and the subsequent stability test took place immediately after the preparation of the formulations, while in examples B4 and B5 the formulations were initially 3

Weeks in air at 20 ° C and only then the flat strips were made and the stability test was carried out.

The test recipes were carried out as follows:

Flat strips were produced according to the recipes and the static thermal stability at 180 ° C was determined. The flat strips were produced by producing a dry blend from the PVC powder and the additives in a Henschel mixer (amount of material = 3 kg, heating temperature = 120 ° C., then cooling). The dry blend was extruded into a flat belt on a twin-screw extruder from Weber. (Extrusion parameters: speed 15 rpm; machine load 44%, temperature 180 ° C). The theme stability of the extruded flat strips was determined using the Congo red method at 200 ° C. The stability test according to the Congo red method [according to the Euro standard EN 6081 3-2rl995 par.9] - works as follows: My samples (50 +5 mg) were taken from the extruded flat strips and placed in the corresponding glass tubes in heated to 200 ° C (± 0.5 ° C) in a metal block. A strip of universal indicator paper was inserted into the top of the glass tube. The time until the color of the indicator paper changed to red was measured in minutes.

Table 1:

It should be noted that the compounds Deawachs LS 567 and calcium hydroxide in Examples 3, 4 and 5 are present in the same amounts and in the same weight ratio.

The Congo red value of Example 3 (comparison) represents a reference value since, as stated above, the production of the flat strips and the subsequent stability test took place immediately after the recipes were produced. In Example 4 (comparison), as stated above, the formulation was stored for 3 weeks before the flat strips were produced and the Congo red value was determined. There was a clear loss of effectiveness.

In Example 5 (according to the invention), as stated above, the formulation was stored for 3 weeks before the flat strips were produced and the Congo red value was determined. It was shown that there was no loss of effectiveness, i.e. the stabilizing effect was just as good as the reference value.

Determination of the uptake of CO ₂ and water

"(Examples B6 and B7)

Example 6

The material was produced analogously to Example 1, using Deawachs LS 567 and calcium hydroxide in a weight ratio of 30: 6. 100 g of the material thus obtained were stored in air at 22 ° C. for 3 weeks. Weighed again to determine how much carbon dioxide and moisture had been released from the air. The sample weighed 100.37 g.

Example 7

The material was produced analogously to Example 2, using Deawachs LS 567 and calcium hydroxide in a weight ratio of 30: 6. 100 g of the material thus obtained were stored in air at 22 ° C. for 3 weeks. Weighed again to determine how much carbon dioxide and moisture had been released from the air. The sample weighed 103.00 g.

The comparison of Examples 6 and 7 makes it clear that the material according to the invention (Example 6) has a considerably reduced carbon dioxide and

n Moisture absorption shows in comparison to the material not according to the invention (Example 7). If the weight gain according to Example 7 is set at 100% (reference value), the weight gain according to Example 6 is only 12%. This means that the matrix-like coating of the calcium hydroxide according to the invention brings about a further technical effect, namely considerably improved protection of the calcium hydroxide against partial or complete deactivation by carbon dioxide during storage.

Claims

Patent claims 1. Use of basic metal oxides and / or hydroxides as an additive for halogen-containing organic plastics, characterized in that the basic metal oxides and / or hydroxides are embedded in an enveloping matrix of hydrocarbons. 2. Use of compositions containing basic metal oxides and / or hydroxides, which are embedded in an enveloping matrix of hydrocarbons, for stabilizing halogen-containing organic plastics, in particular PVC, against thermal and / or photochemical degradation. 3. Containing PVC stabilizer compositions (i) at least one additive sensitive to alkaline compounds and (ii) basic metal oxides and / or hydroxides, which are embedded in an enveloping matrix of hydrocarbons.