GB1587459A

GB1587459A - Moulding compositions and articles made therefrom

Info

Publication number: GB1587459A
Application number: GB40819/77A
Authority: GB
Original assignee: Deutsche Solvay Werke GmbH
Current assignee: Cavity GmbH
Priority date: 1976-09-30
Filing date: 1977-09-30
Publication date: 1981-04-01
Also published as: DE2644079A1; AU2776277A; BE859031A; FR2366328B1; IT1086469B; AU508997B2; FR2366328A1; NZ185131A

Description

(54) MOULDING COMPOSITIONS AND ARTICLES MADE THEREFROM (71) We, DEUTSCHE SOLVAY-WERKE GESELLSCHAFT MIT BESCHRANK TER HAFTUNG, a body corporate organised under the laws of the German Federal Republic, of 6 Langhansstrasse, 5650 Solingen-Ohligs, German Federal Republic, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to fire-resistant or fire-proof articles, such as moulded articles, castings, extruded pipes, cables and the like articles.

It is known that polyvinyl chloride or other polymers containing halogen or moulded articles made therefrom, which in themselves are sparingly combustible, split off hydrogen chloride or hydrogen halide when subjected to flames or in the event bf fire. The hydrogen halide so evolved can lead to damage; thus, for example, the hydrogen halide evolved when polyvinyl chloride is heated reacts with metals, concrete, water and the like or acts on these objects, corrodes them or partially decomposes them. Also the respiration of these split off hydrogen halides is not without danger to man and animals.

In order to solve this problem, therefore, it has been proposed to add to a fire-proof composition comprising a polymer, especially polyvinyl chloride which may be plasticised with a non-combustible plasticiser and a filler, a very finely-divided acid-binding filler with a mean particle size of less than 100 llm for the purpose of binding the volatile halogen acids split off as a result of the action of heat. Examples of such acid-bindng fillers include acid-binding metallic oxides, hydroxides and carbonates, for example magnesium carbonate and chalk.

By means of these acid-binding fillers it is possible for example, rapidly to fix the hydrogen chloride which has been split off from the heated polyvinyl chloride and to reduce or avoid the above-mentioned disadvantages of the action of the acid which can lead to damage. In such cases the action of the acid-binding filler is greater, the more finely-divided the form in which this acid-binding filler is used.

However, there is the disadvantage that the use of the acid-binding filler has an effect on the auto-extinction time. Whereas, for example, polyvinyl chloride itself is sparingly combustible and shows a relatively short auto-extinction time, the auto-extinction time increases with the content of added calcium carbonate. However, as the articles made of the halogen-containing polymer are required to be sparingly combustible or self-extinguishing or almost self-extinguishing, the use of calcium carbonate to bind the hydrogen halide evolved adversely influences the auto-extinction time of the polymer.

It has also been proposed to produce non-inflammable plastic compositions, especially those based on polyester resins, polyethylene, cellulose acetate, cellulose butyrate or polystyrene with the use of aluminium oxide hydrate, anti-oxidants and antimony oxide.

Finally, it has also been proposed to produce a fire-proof, highly plasticised vibrationelastic plastics composition made of polyvinyl chloride which contains more than 400 parts by weight of plasticiser per 100 parts by weight of polyvinyl chloride, at least one-half of the proportion of plasticiser being a phosphate plasticiser. It is also possible for aluminium hydroxide to be added as an inert filler to this fire-proof vibration-elastic plastic composition. The fire-proof action of the highly plasticised composition is achieved as the result of the high proportion of sparingly combustible or fire-inhibiting phosphate plasticiser. However, it is a disadvantage with this fire-proof polyvinyl chloride composition that only certain fire-resisting plasticisers can be used, namely phosphate plasticisers.

Furthermore the proportion of polyvinyl chloride to phosphate plasticiser must be at least in the proportion of 1: 2 and the total proportion of the plasticiser must be maintained at least in the proportion of 1: 4, so that more than 400 parts by weight of plasticiser are present per 100 parts by weight of polyvinyl chloride, of which more than 200 parts by weight or more than one-half consists of phosphate plasticiser. As a result of this plasticiser content the field of application of this composition is restricted. The polyvinyl chloride composition with a very high content of plasticiser is difficult to extrude, expensive and not very suitable for the production of mouldings, castings or extruded cables.

It is an object of the present invention therefore to avoid or reduce the above-mentioned disadvantages and to produce a fire-proof moulding composition containing plasticiser or fire-proof articles, such as moulded articles, castings, extruded tubes, cables and the like made from the composition which comprises a halogen-containing polymer, preferably polyvinyl chloride, which composition is non-inflammable, self-extinguishing or substantially self-extinguishing, free from anti-oxidants and antimony trioxide, and does not evolve or evolves very little free hydrogen halide, or in which the fireproof mouldings, castings, extruded tubes, cables and the like produced from the composition are non-inflammable, self-extinguishing or substantially self-extinguishing, are free from anti-oxidants and antimony trioxide and do not evolve or evolve very little free hydrogen halide as a result of the effect of heat. It was also intended to ensure that it would be possible to use the known combustible plasticisers, for example, phthalate and/or adipate plasticisers, without the necessity for using sparingly combustible plasticisers, for example, phosphate plasticisers.

The fire-proof moulding compound should preferably contain no antimony trioxide additives, because antimony trioxide, although it has a favourable influence on the non-inflammability, nevertheless adversely influences the extrudability, especially the plasticisability of the moulding compound and is comparatively expensive. The fire-proof composition should furthermore be easily processable or easily extrudable and the articles produced from it should be non-inflammable, self-extinguishing or nearly selfextinguishing, free from anti-oxidants and antimony trioxide and should not evolve or evolve little hydrogen halide when heated.

According to the present invention there is provided a fire-proof or fire-resistant moulding composition, comprising a halogen-containing polymer and comprising per 100 parts by weight of said polymer, from above 20 to 140 parts by weight of a filler capable of binding hydrogen halide evolved when the polymer is subjected to heat, the filler having a mean particle size of less than 5 llm., from 40 to 70 parts by weight of a combustible plasticiser for said polymer, and an aluminium-containing compound which is aluminium oxide hydrate, aluminium hydroxide and/or a compound containing aluminium hydroxide and/or aluminium oxide hydrate, the proportion by weight of said filler to said aluminium-containing compound being from 1 : 1 to 10 : 1, the composition being substantially free of anti-oxidants and antimony trioxide.In the present composition, the halogen-containing polymer is preferably polyvinyl chloride, and the moulding composition preferably contains per 100 parts by weight of polymer, from 50 to 100 parts by weight of finely-divided filler, the mean particle size of which is preferably less than 1 um. The composition may also comprise one or more conventional additives and/or processing aids, but is free from anti-oxidants and antimony trioxide. Furthermore, the composition preferably comprises, per 100 parts by weight of polymer, from 45 to 65 parts by weight of combustible plasticiser for the polymer, while the proportion by weight of the finely-divided acid-binding filler to the aluminium-containing compound is preferably 5 : 1 to 10 1.

Whereas in the case of other previously proposed fireproof moulding compositions containing plasticiser, it has been necessary to use non-inflammable plasticisers, for example, phosphate plasticisers, combustible plasticisers, preferably phthalate and/or adipate plasticisers and/or a combination of one of these plasticisers with conventional secondary plasticisers are used in the present composition. Thus, it is possible to do without the more expensive non-combustible plasticisers and to use in part easily processable plasticisers which are those which are preferred for extrusion operations.

The finely-divided filler which binds the hydrogen halide evolved during the action of heat is preferably calcium carbonate, but magnesium carbonate and/or dolomite may also be used as the acid-binding filler. It is also possible to use a mixture of fillers comprising calcium carbonate and other acid-binding fillers, the mixture containing preferably more than 60 per cent by weight of calcium carbonate. The filler which binds the hydrogen halide, preferably calcium carbonate, used in the moulding composition has a mean particle size of less than 5 Clam, preferably less than 1 Clam, because in this state of fine division the hydrogen halide evolved as a result of the action of heat can be bound more rapidly.

It has surprisingly been found that the aluminium hydroxide or aluminium oxide hydrate should preferably have a mean particle size range which is greater than the mean particle size range of the calcium carbonate or other acid-binding filler. The aluminium oxide hydrate or the aluminium hydroxide or a compound which contains aluminium hydroxide or aluminium oxide hydrate therefore preferably has a mean particle size of 0.1 to 50 ssm, more preferably 5 to 20 ,um.

The present fire-proof moulding composition can easily be processed, preferably extruded, and is very suitable for the production of fire-proof mouldings, castings, extruded tubes, cables and the like.

The invention also provides a process for the production of the fire-proof moulding composition, in which the solid or powdered components are mixed in a high-speed mixer.

At a temperature of 60"C. the liquid components are added, preferably the plasticisers of the plasticiser mixture.

The invention also provides articles produced from the composition.

The invention will now be illustrated by the following examples: Example I Parts by weight Suspension polyvinyl chloride, homopolymer, K value 71 (powered) 100 Dioctyl phthalate 50 Tribasic lead sulphate 2.5 Dibasic lead stearate 1.5 Stearic acid 0.2 Calcium carbonate, mean particle size 0.07 iim 100 Aluminium hydroxide, mean particle size 10 iim 20 Example 2 Parts by Weight Suspension polyvinyl chloride, homopolymer, K value 71 (powered) 100 Dioctyl phthalate 50 Tribasic lead sulphate 2.5 Dibasic lead stearate 1.5 Stearic acid 0.2 Calcium carbonate, mean particle size 0.07 ,um 83 Aluminium hydroxide, mean particle size 10 ssm 20 Example 3 Parts by Weight Suspension polyvinyl chloride, homopolymer, K value 71 (powered) 100 Dioctyl phtalate 50 Tribasic lead sulphate 2.5 Dibasic lead stearate 1.5 Stearic acid 0.2 Calcium carbonate, mean particle size 0.07Fm 50 Aluminium hydroxide, mean particle size 10 um 20 In all three examples, the powdered solid components (polyvinyl chloride, tribasic lead sulphate, dibasic lead stearate, stearic acid, calcium carbonate and aluminium hydroxide) were mixed in a high speed mixer and the liquid components, namely the dioctyl phtalate plasticiser was added at a temperature of over 60"C. A moulding was produced from the moulding composition by extrusion.

Extrusions of all three compositions were assessed according to DIN 53438, Process K (behaviour when subjected to flames) to give Class K 1. The post-combustion time in each case was less than 9 seconds. The chlorine combined in the ash depends on the calcium carbonate content and is accordingly between 50 and 100% (ashing at 650"C., according to Leuchs).

WHAT WE CLAIM IS: 1. A fire-proof or fire-resistant moulding composition, comprising a halogen-containing polymer and comprising per 100 parts by weight of said polymer, from above 20 to 140 parts by weight of filler capable of binding hydrogen halide evolved when the polymer is subjected to heat, the filler having a mean particle size of less than 5 ,um, from 40 to 70 parts by weight of a combustible plasticiser for said polymer, and an aluminium-containing compound which is aluminium oxide hydrate, aluminium hydroxide and/or a compound containing aluminium hydroxide and/or aluminium oxide hydrate, the proportion by weight of said filler to said aluminium-containing compound being from 1 : 1 to 10 : 1, the composition being substantially free of anti-oxidants and antimony trioxide.

2. A composition as claimed in Claim 1, wherein the halogen-containing polymer is polyvinyl chloride.

3. A composition as claimed in Claim 1 or 2, wherein the composition comprises from 50 to 100 parts by weight of said filler per 100 parts by weight of said polymer.

4. A composition as claimed in any preceding Claim, wherein the filler has a mean particle size of less than 1 ,um.

5. A composition as claimed in any preceding Claim, wherein the proportion by weight of said filler to said aluminium-containing compound is from 5 : 1 to 10 : 1.

6. A composition as claimed in any preceding claim, wherein the aluminium-containing compound has a mean particle size from 0.1 to 50 Fm.

7. A composition as claimed in any preceding claim, wherein the aluminium-containing compound has a mean particle size of from 5 to 20 Fm.

8. A composition as claimed in any preceding claim, wherein the combustible plasticiser is a phthalate plasticiser, an adipate plasticiser, a mixture of such plasticisers or a mixture of one or more of such plasticisers and a conventional secondary plasticiser.

9. A composition as claimed in any preceding claim, wherein the composition additionally comprises one or more conventional additives and/or processing aids.

10. A fire-proof or fire-resistant moulding composition substantially as hereinbefore described in any one of the foregoing Examples.

11. A fire-proof or fire-resistant article made by moulding, casting or extruding the composition claimed in any preceding claim.

12. A process from producing the composition claimed in any of claims 1 to 10, wherein the solid components in the form of powder are mixed in a high-speed mixer and the liquid component(s) is (are) added at a temperature of over 60"C.

13. A process as claimed in Claim 12, wherein the liquid component is the plasticiser or plasticiser mixture.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. In all three examples, the powdered solid components (polyvinyl chloride, tribasic lead sulphate, dibasic lead stearate, stearic acid, calcium carbonate and aluminium hydroxide) were mixed in a high speed mixer and the liquid components, namely the dioctyl phtalate plasticiser was added at a temperature of over 60"C. A moulding was produced from the moulding composition by extrusion. Extrusions of all three compositions were assessed according to DIN 53438, Process K (behaviour when subjected to flames) to give Class K 1. The post-combustion time in each case was less than 9 seconds. The chlorine combined in the ash depends on the calcium carbonate content and is accordingly between 50 and 100% (ashing at 650"C., according to Leuchs). WHAT WE CLAIM IS:

1. A fire-proof or fire-resistant moulding composition, comprising a halogen-containing polymer and comprising per 100 parts by weight of said polymer, from above 20 to 140 parts by weight of filler capable of binding hydrogen halide evolved when the polymer is subjected to heat, the filler having a mean particle size of less than 5 ,um, from 40 to 70 parts by weight of a combustible plasticiser for said polymer, and an aluminium-containing compound which is aluminium oxide hydrate, aluminium hydroxide and/or a compound containing aluminium hydroxide and/or aluminium oxide hydrate, the proportion by weight of said filler to said aluminium-containing compound being from 1 : 1 to 10 : 1, the composition being substantially free of anti-oxidants and antimony trioxide.