WO1994022815A1

WO1994022815A1 - Haloalkylsulphonylarenes and aryl haloalkanesulphonates as fire retardant additives

Info

Publication number: WO1994022815A1
Application number: PCT/GB1994/000663
Authority: WO
Inventors: Christopher Curtis Dudman
Original assignee: Imperial Chemical Industries Plc
Priority date: 1993-04-01
Filing date: 1994-03-30
Publication date: 1994-10-13
Also published as: AU6433494A; JPH08508294A; ZA942333B; GB9306818D0; EP0691952A1

Abstract

A sulphone or sulphonate of the general formula: A-SO2-(O)x-Ar, wherein x = 0 (sulphone) or 1 (sulphonate); Ar is an aryl group, e.g. Ph; and A is a C2-20 alkyl group bearing at least one halo-substituent, e.g. chloro-octyl, may be used as a fire-retardant additive for organic polymers and particularly as a fire-retardant primary plasticiser for chlorine-containing polymers, e.g. PVC.

Description

HALOALKYLSULPHONYLARENES AND ARYL HOLOALKANESULPHONATES AS FIRE RETARDAN ADDITIVES

The present invention relates to sulphones and sulphonates, particularly halogen-containing sulphones and halogen-containing sulphonates, the use thereof as fire-retardant additives, particularly as fire-retardant primary plasticisers for halogen-containing polymers, methods for the preparation thereof and fire-retarded plastisols and polymer compositions comprising such halogen-containing sulphones and/or halogen-containing sulphonates. Conventional commercially available primary plasticisers for halogen-containing polymers, eg phthalate esters, can be used at high concentrations but are per se often flammable and consequently tend to render polymer compositions containing them more flammable, eg plasticised polyvinyl chloride. So-called secondary plasticisers such as chlorinated paraffins are often used commercially to reduce the flammability of plastics materials, eg polyvinyl chloride (PVC). However, chlorinated paraffins tend to exude from plastic materials, such as PVC, when used at higher concentrations and, accordingly, have to be used at low concentrations which are below the optimum for flammability reduction.

Fire retardant additives for polymer compositions have been disclosed in the following patent specifications.

JA 49003943 discloses the use of bis (1 , 2-dibromomethyl )sulphone for rendering polystyrene fire-proof.

US 3,850,972 suggests the use of certain 2,2-dichloro-l,1-difluoro-ethoxyphenyl bromomethanesulphonates as fire-retardant additives for polystyrene. UK 1,389,462 discloses the preparation of fire-resistant additives containing on average 15 - 70Zw/w chlorine and 1 - 82w/w sulphur by the condensation of a phenolic compound with a gross mixture containing inter alia sulphochlorinated, di-sulphonated and chlorinated paraffins, typically of 10-18 carbon atoms.

US 4,163,005 discloses the use of tris ( 2,2,2-bromomethyl )ethyl trichlorobenzenesulphonate as a fire-retardant in, for example, polyurethane and polystyrene.

UK 1,551,966 discloses fire-retardant polymer compositions comprising a chlorine-containing polymer and a mixture of inter alia certain sulphonates and chlorinated aromatic compounds. UK 1,582,875 discloses flame-retardant compositions comprising polyethylene and certain brominated phenyl arenesulphonates .

EF 0,319,916 discloses the use of certain halogenated 4 , 4 ' -bis (phthalimido )diphenyl sulphones as fire-retardant additives in certain polymers.

US 5,118,739 describes the use of certain metal salts of polybrominated-sulphonic acids as flame-retardant additives for poly(phenylene oxide).

The fire-retardant additives disclosed in the aforementioned patent specifications often exhibit no plasticising effect on the polymer compositions in which they are incorporated.

We have now found that certain dihydrocarbyl sulphones and certain hydrocarbyl esters of hydrocarbonsulphonic acids wherein at least one of the hydrocarbyl groups in the sulphone or ester bears at least one halogen-containing alkyl group overcome many of the aforementioned disadvantages and can be used as fire-retardants in certain polymer compositions with which they are compatible. In particular, they often afford plasticisation of, and have improved compatibility with, polymer compositions, particularly chlorine-containing polyolefins. Furthermore, they are not unduly volatile.

Acccording to the first aspect of the present invention there is provided an organic compound of the 5 General Formula I

A - SO2 - (0)_x - Ar I

wherein:

10 x •= 0 or 1;

Ar is an aryl group; and

A is an alkyl group containing 2 - 20 carbon atoms and bearing at least one halo-substituent .

It will be appreciated that where x in General

15 Formula I is 0 General Formula I represents a sulphone and that where x in General Formula I is 1 General Formula I represents a sulphonate.

According to the second aspect of the present invention there is provided a fire-retardant additive

20 for an organic polymer which additive comprises an organic compound of the General Formula I and which is substantially free of Cι_20 haloalkanes and of disulphonated C1-.2₀ (halo)alkanes .

According to the third aspect of the present

25 invention there is provided a fire-retardant primary plasticiser for a chlorine-containing organic polymer which plasticiser comprises an organic compound of the General Formula I and is substantially free of C _20 haloalkanes and of disulphonated Cι_20 (halo )alkanes .

3_Q By primary plasticiser we mean that the organic compound of the General Formula I is compatible alone with the polymer with which it forms the plastisol or polymer composition as hereinafter defined. A plasticiser is considered to be compatible with a

,c polymeric material if they can be mixed to form a homogeneous composition from which the plasticiser is not lost under the conditions of use of the composition. An indication of the compatibility of the organic compound with the polymeric material with which it forms the plastisol or polymer composition may be obtained from, for example, the Flory-Huggins parameter (X) which may be determined by the method described by C E Anagnostopoulos , A Y Coran and H R Gambraith in Modern Plastics, 1965, Vol. 43(2), 141. For a primary plasticiser the parameter X is less than 0.5.

The alkyl group A in the organic compound of General Formula I may be cyclic, branched or preferably linear; preferably it contains between 6 and 12 carbon atoms, more preferably less than 10 carbon atoms and more particularly preferably about 8 carbon atoms. The alkyl group A in the organic compound of General Formula I may bear substituents such as a halo-alkyl group, eg CCI3-; a halo-acyl group, eg CCI3CO-; a halo-acyloxy group, eg CCI3COO-; or a short chain polyalkylene oxide residue, eg PEG or PPG of MW up to about 400. The at least one halo-substituent on the alkyl group A in the organic compound of General Formula I may be bromo, fluoro or preferably chloro. We do not exclude the possibility that the organic compound may bear a variety of halo-substituents. The number of halo-substituents on the alkyl group

A in the organic compound of General Formula I may be between 1 and n where n is the number of carbon atoms therein.

As examples of the aryl group Ar in the organic compound of General Formula I may be mentioned inter alia fused polycyclic aromatic rings, eg 2-naphthyl, polyaryls, eg biphenyl, heterocyclic rings, eg 2-, 3- or 4-pyridyl, or preferably mono-cyclic aryls, more preferably phenyl . The aryl group Ar in the organic compound of General Formula I may bear substituents such as alkyl, ^e8 ^cl-85 halo, eg Br, Cl, or F; or alkyl-sulphonyl or alkyl-sulphonyloxy , which substituents do not unduly reduce the fire retardency of the organic compound according to the first aspect of the present invention. The weight Z of halo residue, particularly chloro, in the organic compound according to the present invention may be between 15 and 70w/w2, preferably between 20 and 60w/wZ and more preferably between 20 and 40Zw/w. As examples of organic compounds according to the first aspect of the present invention, of fire- retardant additives according to the second aspect of the present invention and of fire-retardant primary plasticisers according to the third aspect of the present invention may be mentioned inter alia chlorinated-octyl phenyl sulphone, chlorinated-octyl p-tolyl sulphone, phenyl ester of chlorinated- octanesulphonic acid or of chlorinated- hexadecanesulphonic acid and 2 , 4-dichlorophenyl chlorinated-octanesulphonate .

Where the organic compound of General Formula I is an aryl haloalkyl sulphone, ie x in General Formula I is 0, it may be prepared by a process which comprises the steps of: A. reacting an alkali metal sulphite, preferably sodium sulphite, with an arylsulphonyl halide, preferably an arylsulphonyl chloride;

B. reacting the alkali metal arylsulphinate prepared in Step A with a haloalkane, preferably a bromoalkane; and

C. halogenating , preferably chlorinating, the alkyl aryl sulphone prepared in Step B.

In the aforementioned Step A, the arylsulphonyl halide is preferably treated with an excess of alkali metal sulphite. The reaction is preferably carried out in the presence of a weak base, eg sodium bicarbonate, to avoid loss of sulphite, at elevated temperature, eg above 50°C, and preferably between 70 and 80°C.

In the aforementioned Step B, the reaction is preferably carried out in a dipolar aprotic solvent, eg N-methylpyrollidone . However, we do not exclude the possibility that an alternative procedure may be used, eg a phase transfer technique. Where the reaction in Step B is carried out in a dipolar aprotic solvent it is typically carried out at elevated temperature, eg above 100°C, preferably at about 110-120°C, for about 5-6 hours.

In the aforementioned Step C, halogenation is conveniently carried out in diffuse sunlight at elevated temperature, eg about 90-110°C, using a flow of gaseous halogen, particularly chlorine. The skilled man, by simple experiment, will be able to determine specific experimental conditions for each of the aforementioned Steps A - C.

We have found that where the organic compound of General Formula I is an aryl ester of a haloalkanesulphonic acid, ie x in General Formula I is 1, it may be prepared by the steps of:

D. treating a haloalkane, preferably a bromoalkane, with an alkali metal sulphite, preferably sodium sulphite; or, preferably, reacting ammonium sulphite with an α-olefin in the presence of a radical initiator;

E. reacting the alkanesulphonate prepared in Step D with a thionyl halide, preferably thionyl chloride;

F. reacting the alkanesulphonyl halide prepared in Step E with a halogen, preferably chlorine; and

G. reacting the halogenated alkanesulphonyl halide prepared in Step F with an arylhydroxy compound, preferably phenol, in the presence of a base.

According to a further aspect of the present invention there is provided a process for the preparation of an aryl ester of a sulphonate of General Formula I wherein x = 1 which process comprises at least the step of reacting an alkanesulphonate with a thionyl halide, preferably thionyl chloride.

Where, in the aforementioned Step D, the haloalkane is treated with an alkali metal sulphite, it is preferably treated with an excess of the alkali metal sulphite in an aqueous medium in the presence of a phase transfer catalyst, eg tetra- n-butylammonium chloride. The reaction is carried out at elevated temperature above 50°C and typically at the reflux temperature of the reaction mixture. We do not exclude the possibility that the reaction may be carried out at elevated pressure.

In the aforementioned Step E, the alkanesulphonate prepared in Step D is treated typically with an excess of thionyl halide containing a catalytic amount of a tertiary amide, eg N-methylpyrollidone .

In the aforementioned Step F, halogenation is conveniently carried out at elevated temperature, eg about 90°C, using a flow of gaseous halogen, particularly chlorine. Chlorination is preferably carried out in the absence of radical initiators to avoid undesirable residues and without irradiation to avoid the production of undesirable byproducts.

In the aforementioned Step G, the halogenated alkanesulphonyl halide prepared in Step F is preferably added to a solution of the arylhydroxy compound in aqueous alkali-metal hydroxide solution. We have found that the use of ammonia as the base in Step G leads to the production of substantial amounts of undesirable sulphonamides .

The skilled man, by simple experiment, will be able to determine specific experimental conditions for each of the aforementioned Steps D - G.

According to a yet further aspect of the present invention there is provided a plastisol comprising a polymer as hereinafter described and a fire-retardant primary plasticiser according to the third aspect of the present invention.

As examples of polymers of which the plastisol according to the present invention may be comprised may be mentioned chlorine-containing polymers, particularly PVC, and acrylic polymers.

A PVC plastisol is defined in "The Technology of Plasticisers", J Kern Sears and Joseph R Darby, John Wiley and Sons Inc., 1982 as " a pourable, creamy dispersion of finely divided PVC in a liquid plasticiser." A PVC plastisol is typically prepared by suspending very fine particles of PVC, prepared by emulsion polymerisation, in a plasticiser.

Usually such a plasticiser is liquid at room temreature but we do not exclude the possibility that a solid plasticiser could be used in conjunction with a liquid plasticiser to give a plastisol with the desired flow properties.

When a plastisol is heated to a suitable temperature the plasticiser migrates into the polymer particles which then swell and coalesce. The skilled man will find by simple experiment such a suitable temperature for a plastisol according to the present invention. For PVC, for example, it is about 160°C. On cooling, a flexible solid product is obtained which is hereinafter referred to for convenience as a "polymer composition" .

Alternatively, particularly where the polymer does not form a plastisol, the polymer composition may be prepared by incorporating the fire-retardant additive into the polymer by conventional formulation procedures .

According to a yet further aspect of the present invention there is provided a fire-retarded polymer composition comprising a polymer as hereinafter described and a fire-retardant additive according to the second aspect of the present invention.

As examples of polymers of which the fire-retarded polymer composition according to the present invention may be comprised may be mentioned inter alia elastomers, eg natural rubber, butadiene/ styrene copolymers, polyurethanes ; thermoset resins, eg unsaturated polyesters, epoxy resins; and thermoplastics, eg polyamides ,acrylic resins, particularly halogen-containing polyolefins and more particularly chlorine-containing polyolefins, eg PVC. Where the plastisol or polymer composition according to the present invention comprises a chlorine-containing polymer it may be a homopolymer or a copolymer containing at least 5Z, preferably more than 20Z and more preferably more than 40Z w/w chlorine. As examples of such polymers may be mentioned inter alia chlorinated polyethylene, poly-vinylidene chloride, or preferably a PVC, eg vinyl chloride/vinyl acetate copolymer, vinyl chloride/acrylic ester copolymers and polymer blends, eg PVC/rubber blends, or more preferably PVC.

Sufficient organic compound of the General Formula I is mixed with a polymer to afford a polymer composition according to the present invention having the desired flexibility and flame-retardency after suitable processing, eg heat treatment. It will be appreciated that the plasticiser softens the polymer and modifies certain other properties thereof, eg tensile strength. The amount of the organic compound needed to confer fire-retardancy to the polymer composition according to the present invention will be determined by the skilled man by simple experiment. For example, where the polymer composition according to the present invention comprises PVC it typically comprises at least about 10 parts and where a soft PVC is required up to about 120 parts by weight of the organic compound per 100 parts by weight of PVC.

It will be appreciated that the organic compound of the General Formula I of which the plastisol according to the present invention is comprised will be (a) sufficiently involatile such that evaporation thereof from the plastisol during processing is not excessive and (b) sufficiently thermally stable such that it does not decompose to an undesirable extent during processing of the plastisol. It will be appreciated that the organic compound of the General Formula I of which the fire-retarded polymer composition according to the present invention is comprised will be (a) sufficiently involatile such that the properties of an article prepared from the polymer composition are not unduly changed during its useful working life by evaporation of the organic compound therefrom and (b) will be sufficiently thermally stable such that it does not decompose to an undesirable extent during the useful working life of an article prepared from the polymer composition.

The plastisol and polymer composition according to the present invention may also contain further components, eg heat stabiliser, light stabiliser, anti-oxidant , filler, pigment, lubricant, fungicide or other components used in the art.

Whereas the organic compound according to the first aspect of the present invention is primarily a fire-retardant primary plasticiser for halogen-containing polymers, particularly PVC, it may be used as a fire-retardant additive for other polymers as hereinbefore described, eg polyurethanes , and may also be used as arc-extinguishing fluids or extreme-pressure lubricant additives.

The plastisol and polymer composition according to the present invention can be formed into articles by conventional polymer-forming techniques, eg injection moulding, extrusion, spread-coating, calendering, slush moulding and blow-moulding techniques.

As examples of products prepared from polymer compositions according to the present invention, particularly polymer compositions based on a PVC, may be mentioned inter alia conveyor belts, electric-cable coating and flooring.

The present invention is further illustrated by reference to the following Examples which illustrate, by way of example only, certain aspects of the present invention.

In the Examples the viscosity of the organic compound according to the first aspect of the present invention was measured at 25°C using a calibrated glass viscometer.

EXAMPLE 1

This Example illustrates a chlorinated-octyl phenyl sulphone according to the present invention. Step A A* flask fitted with a mechanical stirrer, reflux condenser and nitrogen inlet and containing a mixture of sodium sulphite (300g, 2.38 moles), sodium bicarbonate (210g, 2.5 moles) and water (1.2L) was purged with nirogen. Stirring was commenced and the flask was heated in an oil bath to 74°C.

Benzenesulphonyl chloride(116.8ml , 224g, 1.27 moles) was added to the mixture dropwise over 3 hours while the temperature was maintained between 70°C and 80°C; heating was continued for a further 1 hour. The mixture was allowed to cool overnight; the crystalline precipitate which formed was recovered by filtration and the filtrate was concentrated to provide a further crop of crystals. The product, sodium benzenesulphinate , was allowed to dry in a dessicator. S tep B

N-methyl-pyrollidone (980 ml) and 1-bromooctane (219 ml, 245g, 1.27 moles) were added to the product from Step A in a flask fitted with a stirrer, nitrogen inlet and a reflux condenser and the mixture was heated with stirring at 114-116°C for 5-6 hours and then allowed to cool overnight.

Water and hexane were added to the reaction mixture, the organic layer was separated, the hexane was evaporated off and the residue was distilled at reduced pressure to yield octyl phenyl sulphone as shown by GC-MS. Step C

The octyl phenyl sulphone prepared in Step B was chlorinated in a glass vessel in diffuse sunlight at 100-104°C for 1 hour 44 minutes with a chlorine flow rate of 12L/hour.

The chlorinated-octyl phenyl sulphone recovered therefrom was found to contain 20.18Z chlorine by weight and had a viscosity of 3.66 poise.

EXAMPLES 2-3

These Examples illustrate further chlorinated- octyl aryl sulphones according to the present invention. The procedure of Example 1 was repeated except that in Step C a longer chlorination time was used to produce a product with a higher chlorine content; and in Example 3, p-toluenesulphonyl chloride was used instead of benzenesulphonyl chloride in Step A. The chlorine contents and viscosities of the products are shown in Table 1. TABLE 1

Example No Weight Z chlorine Viscosity (poise )

2 j 23.5 6.07 3 j 21.9 5.8

EXAMPLE 4

This Example illustrates a phenyl chlorinated- octanesulphonate according to the present invention. Step D

A mixture of 1-bromooctane (300g, 1.7 moles), sodium sulphite (323g, 2.56 moles), water (1530 ml), propan-2-ol (600ml) and tetra-n-butylammonium chloride (6.6g, 23.8 mmoles; phase transfer catalyst) in a 3 litre flange flask was stirred until two clear colourless liquid phases were obtained. These were heated under reflux at 84°C for 24 hours. The reaction mixture was allowed to cool to room temperature yielding a single liquid phase containing a small quantity of a white solid which was removed by filtration. Sodium chloride (450 gm, 7.7 moles) was added to the filtrate to precipitate the sodium octanesulphonate. The precipitate was filtered off, washed twice with saturated sodium chloride solution (250ml), then dried in a vac oven at 140°C and 1mm Hg pressure for 20 hours. Step E

Thionyl chloride containing ,N-dimethylformamide (230ml, 3.1 moles thionyl chloride/29.7 mmoles N,N-dimethylformamide ) was added to the dried sodium octanesulphonate prepared in Step D and the mixture was heated slowly to 60°C; after 5-6 hours the temperature was raised to 90°C and heating was continued for a further 6 hours. The reaction mixture was cooled and poured cautiously onto ice-water (2 litres) . The product was extracted with ether, the organic layer was washed twice with water, dried over magnesium sulphate and evaporated to leave an oil. The oil was vacuum distilled and afforded 313.5g (86Z yield) of a clear colourless oil b.p. 105-106°C/lmm Hg . Step F

A sample (150g, 0.705 moles) of the octanesulphonyl chloride prepared in Step E was charged to a chlorination vessel. It was purged with nitrogen at 0.4L/min for 30 minutes, then heated to 90°C; the nitrogen flow was stopped and chlorine gas was passed into the octanesulphonyl chloride at 0.3L/min. Initially the reaction temperature was maintained at 95°C by cooling the reactor with water, then it was allowed to rise to 110°C. After 106 minutes the chlorine flow was discontinued and the mixture was purged with nitrogen for 30 minutes. The product, chlorinated octanesulphonyl chloride, was found to have an average formula of C8--15 _# χClι . gSO∑Cl . Step G

50Z Aqueous sodium hydroxide solution (44.24g, 0.553 moles sodium hydroxide) and then chlorinated octanesulphonyl chloride prepared in Step F (150g, 0.539 moles) were added slowly with stirring to phenol (53.32g, 0.567 moles) while the reaction temperature was maintained at 50-60°C.The mixture was heated to 80°C for a further 1 hour with occasional swirling. The reaction mixture was washed twice with 1Z sodium hydroxide solution (100ml) and then with water until the washings were neutral. Residual water was removed from the product by evaporation at 80°C/lmm Hg.The product was a pale yellow oil, 155.2g (86Z yield), it had an average formula of C14H20. l^cll .9^S03 (corresponding to a chlorine content of 20Z by weight and a viscosity of 1.9 poise. EXAMPLES 5-7

These Examples illustrate further aryl esters of chlorinated-octanesulphonates according to the present invention.

The procedure of Example 4 was repeated except that: a) in Examples 5 and 6, a longer time was used in Step F to afford a product with a higher Cl content ; and b) in Example 7, 2 , 4-dichlorophenol was used instead of phenol in Step G.

The chlorine contents and viscosities of the products are shown in Table 2.

TABLE 2

Example No Viscosity

(Z by weight) (poise )

5 28 10.51 6 33 27.07 7 20 6.0

EXAMPLES 8-14

Examples 8-13 illustrate plastisols and polymer compositions according to the present invention; Example 14 is a Comparative Test.

Plastisols, wherein the fire-retardant primary plasticiser was a halo-sulphone or a halo-sulphonate prepared in Examples 2 - 7, were prepared by charging the components of the composition to a Casbert Blender, evacuating the blender, stirring the mixture for 10 minutes, releasing the vacuum, scraping down the mixture back to the stirrer blades and stirring for a further 20 minutes under vacuum. The plastisols and polymer compositions used in Examples 8-13 contained the components shown in Table 3.

TABLE 3

! Component I Parts by weight ! (pph)

p

Grade P72/755 ex European Vinyls Corporation.

TBLSJ Tribasic lead sulphate. Reoplas 39 Epoxidised vegetable oil stabiliser.

Snowcal 70: Calcium carbonate filler

The plastisols were converted into polymer compositions by heat treatment under the conditions described in the following General Method.

General Method

The plastisol was spread on waxed paper into a film 0.8mm thick. The film was heated in a Werner Mathis oven, preheated to 160°C, at 160°C with internal air circulation for 2 minutes. It was removed from the oven and allowed to cool. The cooled cured film was removed from the paper and cut into strips of a size appropriate to a template mould. They were stacked in the template mould until the desired thickness was obtained, ie thickness of the mould; sheets of polyester film were were placed at the top and bottom of the mould to facilitate release from the mould. The template was placed in a Moore press pre-heated to 160°C. Where the samples were 1.27mm thick the faces of the press were brought into contact with the top and bottom of the mould for 5 minutes, then the maximum pressure of the press was applied at 160°C for 2 minutes; where the samples were thicker than 1.27mm the faces of the press were brought into contact with the top and bottom of the mould for 10 minutes, then the maximum pressure of the press was applied at 160°C for 5 minutes.

The press was allowed to cool under pressure until the temperature reached 25°C, then the pressure was released and the samples were removed from the template. The samples were cut into the appropriate size and shape for the following tests. A) The limiting oxygen index (LOI) of the polymer composition was measured by burning strips (15cm x 6mm x 3mm) thereof in an atmosphere of nitrogen and oxygen and determining the minimum percentage oxygen by volume required to sustain combustion of the strip for 3 minutes ; B) British Standard Softness (BSS) was determined by measuring the depth of penetration of a ball-ended plunger of diameter 2.38mm into a disc-shaped sample (10.2mm thick) of the polymer composition relative to a small foot resting on the surface of the disc which had been aged for seven days prior to testing. An initial load (30g) was applied to the plunger for 5 seconds then a final load (565g) was applied for 30 seconds. Penetration of the plunger was read from a gauge calibrated in units of 0.01mm, which corresponds to British Standard Softness. During the loading period the equipment was gently vibrated to overcome any friction.

The results are shown in Table 4 from which it can be seen that halo-sulphones and halo-sulphonates are compatible with PVC and that polymer compositions having good fire-retardency (high LOI) and good plasticising capability (high BBS) were obtained at low levels of halosulphone and halo-sulphonate incorporation. No exudation of the plasticiser from the polymer composition was observed, suggesting good compatibility of the plasticiser with PVC.

Comparison of the results from Examples 8-13 with Example 14 reveals that organic compounds according to the present invention give better fire-retardancy than a commercially available fire-retardant.

TABLE 4

Example Fire-retardant Properties of No primary plasticiser polymer compositions

Source Name (Example No. ) LOI ! BSS

8 2 COPSN 31 5 45.59

9 3 COTSN 32 5 47.88

10 4 CPOST 32 5 49.6

11 5 COPSTL 39 37.15

12 6 COPSTH 39 5 46.93

13 7 CDOST 40 41.63

14 ! Reofos

COPSN chlorinated octyl phenyl sulphone. COTSN chlorinated toluyl phenyl sulphone CPOST chlorinated phenyl octylsulphonate CPOSTL chlorinated phenyl octylsulphonate

(lower Cl content).

COPSTH: chlorinated phenyl octylsulphonate

(higher Cl content).

CDOST chlorinated 2 , 4-dichlorophenyl octanesulphonate .

Reofos isopropylated triaryl phosphate.

EXAMPLE 15

This Example illustrates a further halogenated aryl alkanesulphonate according to the present invention and the use thereof as a plasticiser.

The procedure of Example 4 was repeated except that 1-bromohexadecane was used instead of 1-bromooctane in Step D. The phenyl chlorinated-hexadecanesulphonate prepared therefrom had a chlorine content of 23Zw/w.

The procedure of Examples 8-13 was repeated except that the phenyl chlorinated-hexadecanesulphonate was used as the plasticiser at 75pph. The polymer composition had an LOI of 34.5

EXAMPLE 16

This Example illustrates a plastisol and a polymer composition according to the present invention comprising additionally a commercially available fire-retardant (Cereclor (RTM) S45).

A plastisol composition was prepared by charging the components of the composition to a Casbert Blender, evacuating the blender, stirring the mixture for 10 minutes, releasing the vacuum, scraping down the mixture back to the stirrer blades and stirring for a further 20 minutes under vacuum.

The plastisol was converted into the corresponding polymer composition by the procedure described in Examples 8-13.

The plastisol and polymer composition contained PVC (Grade P72/755 ex European Vinyls Corporation; lOOpph), a sample of chlorinated octyl phenyl sulphone prepared in Example 1 (54pph) and Cereclor S45 (RTM; ex ICI; 21pph). The polymer composition was found to have an LOI of 31.5 and a BSS of 51.44. It was found that none of the chlorinated octyl phenyl sulphone or Cereclor exuded from the polymer composition.

Thus revealing that a combination of a halo-sulphone according to the present invention and a commercially available fire-retardant secondary plasticiser acts as a fire-retardant additive and as a plasticiser and is compatible with PVC.

Claims

1. An organic compound of the General Formula A-S02-0_X-A_r wherein x= 0 or 1; A_r is an aryl group; and

A is an alkyl group containing 2-20 carbon atoms and bearing at least one halo-substituent .

2. An organic compound as claimed in Claim 1 wherein the alkyl group A contains between 6 and 12 carbon atoms.

3. An organic compound as claimed in Claim 1 wherein the at least one halo-substituent on the alkyl group A is a chloro-substituent .

4. An organic compound as claimed in Claim 1 wherein the aryl group A_r is a mono-cyclic aryl group.

5. A process for the preparation of an organic compound as claimed in Claim 1 wherein x=l which process comprises at least the step of reacting an alkanesulphonate with a thionyl halide.

6. A fire-retardant additive for an organic polymer which additive comprises an organic compound as claimed in Claim 1 and is substantially free of Cι_20 haloalkanes and of disulphonated Cι_2Q (halo )alkanes .

7. A fire-retardant primary plasticiser for a chlorine-containing organic polymer which plasticiser comprises an organic compound as claimed in Claim 1 and which is substantially free of Cι_20 halocarbons and of disulphonated Cι_20 (halo) lkanes .

8. A plastisol comprising a chlorine-containing polymer and a fire-retardant primary plasticiser as claimed in Claim 7.

9. A plastisol as claimed in Claim 8 wherein the chlorine-containing polymer is a PVC.

10. A fire-retarded polymer composition comprising a polymer and a fire-retardant additive as claimed in Claim 6 which is compatible therewith.

11. A fire-retarded polymer composition as claimed in Claim 10 wherein the polymer is a chlorine-containing polyolefin.

12. A fire retarded polymer composition as claimed in Claim 11 wherein the chlorine-containing polyolefin is a PVC.