FR2614624A1 - FLAME RETARDANT ADDITIVE FOR THERMOPLASTIC MATERIALS - Google Patents

Abstract

A FIRE-RETARDANT ADDITIVE FOR THERMOPLASTIC RESINS IS PROVIDED COMPRISING: (I) 20 TO 60 BY WEIGHT OF A SILICONE OIL; (II) FROM 10 TO 40 BY WEIGHT OF A SILICONE RESIN AND (III) FROM 5 TO 60 BY WEIGHT OF A GAS-PRODUCING AGENT CHOSEN FROM THE GROUP CONSISTING OF COMPOUNDS CONTAINING BOTH PHOSPHORUS AND L ' NITROGEN OR A MIXTURE OF COMPOUNDS CONTAINING PHOSPHORUS WITH COMPOUNDS CONTAINING NITROGEN. THERMOPLASTIC RESINS AS FIRE-PROOF CAN BE MOLDED, EXTRUDED, COMPRESSED OR SPINNED, ETC., TO FORM A LARGE NUMBER OF USEFUL PRODUCTS, AMONG WHICH WE CAN CITE, COATINGS, OBJECTS MOLDED BY INJECTION, SHEETS AND FIBERS OTHER PRODUCTS FINDING APPLICATIONS IN AUTOMOTIVE, ELECTRICITY, ELECTRONICS.

Description

-1'q 2614624

  FLAME RETARDANT ADDITIVE FOR THERMOPLASTIC MATERIALS

  The present invention relates to

  fugents and in particular flame retardant additives for thermoplastics. The present invention relates, more particularly, to flame-retardant additives based on silicones for thermoplastics, which can be,

among others, polyolefins.

  In the past, considerable efforts have been made to

  to obtain flame retardant thermoplastic resins without the use of halogens. It was conventionally necessary to heavily load the plastic or thermoplastic material with additives until the desired degree of fire resistance was achieved. The use of heavy additive feeds has several disadvantages due to the fact that it is normally expected that a large proportion of additives will impair the physical properties of the plastic material. In addition, the additive can bring complications inherent to the additive itself, such as, for example, the formation of foam, which will have to be done

  in addition to a general decline in physical properties.

  The present invention provides flame retardant additives

  that do not only provide better resistance

  in the absence of organic halides, but also

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  do not lead to poor fitness for transformation.

  which could have been expected from the prior art. U.S. Patent No. 4,387,176 discloses a flame retardant additive for thermoplastics which contains a silicone oil, a silicone resin and a Group IIA metal salt. When adding a halogen, this flame retardant additive is the only

more efficient.

  U.S. Patent No. 4,115,351 discloses synthetic fibers dipped in solutions containing inorganic phosphorus compounds and inorganic nitrogen compounds. To make it more convenient to use the compounds in the solution in which they are immersed, they are coated with inactivating materials, among which mention may be made of silicones, paraffins and

fats.

  U.S. Patent No. 3,936,416 discloses the use of ammonium polyphosphate and

  dipentaerythritol as flame retardant in polypro-

  pylene. In addition to an insufficient flame retardant effect, it is difficult to form a foam by the flame retardant during the melt processing of the polypropylene. The object of the present invention is to produce a flame retardant additive containing no halogens for a

thermoplastic resin.

  It is also intended to produce a flame retardant additive containing no halogens having an effect

superior flame retardant.

  It is another object of the present invention to provide a flame retardant agent containing phosphorus and nitrogen for thermoplastic resins that does not foam.

  during processing in the molten state.

  In brief, the present invention provides a composition

Flameproofed composition comprising:

  (A) 100 parts by weight of a thermoplastic resin

  and (B) from about 2 to about 30 parts by weight of a flame retardant additive comprising:

  (i) from 20 to 60% by weight of a silicone oil

cone,

  (ii) from 10 to 40% by weight of a silicone resin

  and (iii) from 5 to 60% by weight of a gas producing agent selected from the group consisting of

  compounds containing both phosphorus

  phore and nitrogen or a mixture of

  poses containing phosphorus with

placed with nitrogen.

  We can possibly add a polyol to

promote the formation of coal.

  The flame retardant additive contains as constituent

  of about 40 to 80% by weight of a silicone oil.

  cone. The term "silicone oil" as used

  here covers a wide range of polysilonous

  which can be advantageously used in the

  of the present invention. For the purposes of the pre-

  description, it must be understood that the expression

  "silicone oil" covers those of these silicone

  and those which are effective, such as those described by MacLaury and Holub in U.S. Patent No. 4,273,691 and other effective silicone materials, several of which will be described below. An effective silicone will be conventionally chosen from fluids or silicone gums which are polyorganosiloxane polymers.

  composed of siloxy units combined chemically with conventional

  chosen from the group consisting of R3-

  SiO 0.5, R 2 SiO, R SiO RR 2 SiO 5, RR SiO, R 1 SiO 1.5 R 1 R 2 SiO 0.5, RR 1 SiO, (R) 2 SiO, RSiO 1.5 and SiO 2 and mixtures thereof, knowing

  that each of the R groups independently represents a radical

  monovalent hydrocarbon saturated or unsaturated hydrocarbon, R1 represents

  a radical such as R or a radical selected from the group consisting of a hydrogen atom, hydroxy, alkoxy, aryl, vinyl or allyl radicals, etc., and that the polyorganosiloxane has a viscosity of between about 600 and 300,000. Of centipoises at 25 C. It is recommended as a silicone oil a polydimethylsiloxane having a

  viscosity between about 90,000 and 150,000 centi-

  poises at 25 C. These silicone oils must be distinguished

  of the group of materials called silicone resins

  cones. It is easy to get these silicone oils

  under a wide variety of brands and qualities.

  The flame retardant additive contains as another

  killing principal, a group of materials called silicone resin. Silicone resins are well known materials in various forms; From about 2 to about% by weight of the total composition of the additive will be a silicone resin that is soluble in the silicone oil described above (i.e., a fluid or gum) and which is effective in imparting fire resistance properties to the compositions of the present invention. Among the resins of

  Silicones recommended silicone resins MQ. The ex-

  "silicone resin MQ" pressure is derived from the fact that these resins are conventionally composed mainly of monofunctional units M having the formula R3SiO05 and tetrafunctional units Q having the average formula SiO2, with a given ratio of units M to Q units. A poly ( trimethylsilyl silicate) which may have a ratio of about 0.3 to 4.0 M units per unit Q is an effective silicone resin when used in the present invention and may be mentioned. A particularly effective flame retardant additive could preferably contain from 6 to 30% by weight of such MQ resin and have a ratio of about 0.6 to 2 M units per Q unit. MQ trade the SR 545 from General Electric (60% solids MQ resin in toluene). A recommended method of using this type of MQ resin solution is to mix it with the silicone oil and then remove the solvent. The solvent can be removed by well known methods, for example

  example by distillation at moderate temperature.

  It is considered that other forms of soluble solid silicone resins can be effectively employed.

  in silicone oils in flame retardant compositions.

  of the present invention. Silicone resins

  MT and TQ (T representing patterns RSiO1, 5 trifunction-

  nels) can, in fact, be effective as well as mixtures and copolymers of each of the resins mentioned. These silicone resins are well known materials and are readily available. To agree,

  these resinous materials of effective silicones must satisfy

  to the criteria of solubility or dispersibility in

  the silicone oil constituting the base of the mixture.

  In addition, it should be noted that although

  in the composition of the additive, the silicone oil (es-

  with the function D) and the silicone resin (with M, D, T or Q function) as distinct constituents to be mixed, it should be understood that the present invention includes the reaction products of these materials.

  which can also be effective as flame retardant

  giants. It is also foreseeable that it is possible to use a copolymer containing the desired M, D, T or Q functional groups in place of silicone oil and

Silicone resin separate.

  The flame retardant additive composition further contains a gas producing agent. Suitable gas producing agents are compounds containing both phosphorus and nitrogen or a mixture of compounds containing

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  Phosphorus and compounds containing nitrogen. The gas producing agent has the main function of producing gas when heated and thus delaying the supply of oxygen. The gas-producing agent can also further decrease the temperature to form an extinguishing liquid

  which is able to cover the ignition sites.

  The preferred gas producing agents are compounds, and particularly inorganic compounds, containing both phosphorus and nitrogen. We can

  appropriate compounds of this type, poly-

  ammonium phosphates having the general formula (NH4) n + 2PnO3n + 1 wherein n is greater than 2;

  ammonium phosphates, such as monoammonium orthophosphate

  monique (NH4) H2PO4, diammonium orthophosphate (NH4) 2HPO4, triammonium orthophosphate (NH4) 3 PO4; ammonium pyrophosphates such as monoammonium pyrophosphate (NH4) H3P207, diammonium pyrophosphate (NH4) 2H2P207 and other ammonium pyrophosphates such as (NH4) 3HP207, (NH4) 4P207; ammonium phosphites such as (NH4) H2PO3, (NH4) 2HPO3; ammonium hypophosphates such as (NH4) 2H2P206, (NH4) 3HP206; ammonium hypophosphites such as (NH4) H2PO2, (NH4) 2HPO2; ammonium metaphosphate such as (NH4) PO3 and monoammonium phosphite etc. In addition to these examples, mention may also be made of compounds containing other metallic elements and for example sodium and ammonium phosphate NaNH 4 HPO 4,

  ammonia-magnesium phosphate (NH4) MgPO4, phosphorus

  ammonium molybdate (NH4) 3PO4x12MoO3, phosphorus

  ammonium tungstate (NH4) 3PO4, 12W03, cobalt and ammonium phosphate (NH4) CoPO4, ammonium manganese phosphate (NH4) MnPO4. We can also

  include compounds containing halogens such as difluoro-

  Ammonium rophosphate (NH4) P02F2, hexafluorophosphate

  Ammonium (NH4) PF6, diamino trichloride

-7-

  phosphorus C13P (NH2) 2, tri (phosphorus nitrilochloride)

  phore) (PNC12) 3, and other compounds such as a phosphorus

  amide OP (NH2) 2, the metaphosphinic acid P3N3-

  (OH) 6 and its ammonium salt P3N306H3 (NH4) 3, triammonium trithiophosphate (NH4) 3POS3. We can

  also mention the hydrates of the above compounds.

  Other examples of gas producing agents containing both nitrogen and phosphorus, phosphine oxide, melamine pyrophosphate, pentate salts containing nitrogen, and the like. U.S. Patent No. 4,154,930 still describes

  pentate salts containing nitrogen.

  As mentioned above, the gas-producing agent may also be a mixture of phosphorus-containing compounds with nitrogen-containing compounds. Phosphorus-containing compounds, phosphoric acid, phosphorous acid, metaphosphoric acid, metaphosphorous acid, hypophosphorous acid,

  pyrophosphorous, hypophosphoric acid, pyrophosphate

  phoric and preferably their salts. We can mention, by

  example, among the salts, a sodium salt, a potassium salt,

  sium, a lithium salt, a beryllium salt, a magnesium salt, a calcium salt, a zinc salt, a cadmium salt, an ammonium salt, etc. Examples of phosphorus-containing compounds include monopotassium phosphate KH2PO4,

  dipotassium phosphite K2HPO3, the tetra-pyrophosphate

  Potassium K4P207 'magnesium pyrophosphate Mg2P207, a potassium metaphosphate (KPO3) n, monosodium potassium monopotassium phosphate NaKHPO4x7H2O, the

  disodium pyrophosphate Na2H2P207, hexametaphos-

  sodium phat (NaPO3) 6 disodium hypophosphate

  Na2H2P206, trisodium phosphate Na3-

  PO4x12H20, disodium phosphite Na2HPO3x5H20, disodium phosphomolybdate Na2PO4 x12M003, trilithic phosphate Li3PO4x1 / 2H20, phosphate

  dimagnesium MgHPO4x3H20, disodium phosphate Na2-

  HPO4 and its hydrates (Na2HPO4x2H2, Na2HPO4-

4 N2HP4x2H20, N2HP4-

  x7H20, Na2HPO4x12H2O, monosodium phosphate NaH2PO4xH20, monomagnesium phosphate MgH4-

  (PO4) 2x3H2O, trimagnesian phosphate Mg3-

  (PO4) 2x5H20, dicalcium phosphate CaHPO4x2H20, monocalcium phosphate CaH4 (PO4) 2, phosphite of

  CaHPO3 calcium, trizincic phosphate Zn3 (PO4) 2-

  x4H20, bizincic phosphite ZnHPO3, zinc pyrophosphate Zn2P207, aluminum phosphate AlPO4, etc. Compounds containing nitrogen are easy to

  obtain and are preferably ammonium compounds.

  Suitable ammonium compounds include chlorine

  ammonium carbonate, ammonium carbonate, ammonium carbonate, ammonium nitrate, ammonium sulphate,

  ammonium sulphate and ammonium phosphates.

  Of course, two or more phosphorus-containing compounds can be mixed with two or more

  compounds containing nitrogen. Those skilled in the art can determine

  to reduce the relative proportions of phosphorus compounds and nitrogen compounds necessary to achieve the desired effect as a gas-producing agent. This proportion will obviously vary depending on the particular compounds

employees.

  The flame retardant additive composition may optionally, but preferably, include a polyol. The polyols useful in this invention are acyclic and cyclic compounds to which several hydroxy groups are attached and, for example,

  among these compounds, pentaerythritol, dipentaeryl

  thritol, tripentaerythritol, pentitols such as adeno-

  tol, arabitol, etc., hexitols such as dulcitol, inositol, etc. and saccharides such as amylose, xylan, etc., as well as derivatives of these compounds such as N-methylglucamine. The polyol appears to function as an additional source of carbon for the agent

  producing gas which has the effect of increasing the quantity

  and reduce the amount of gas-producing agent required to provide useful flame retardancy. The choice of the amount of polyol employed will therefore necessarily depend on the amount of gas-producing agent used, and in general, the weight ratio of the gas-producing agent to the polyol will be from about 9: 1 to about 5: 1. . When polyol is used in quantities

  less important so that the ratio is higher than

  around 10: 1, the improvement in the

  Coal formation becomes negligible, while the

  the polyol in larger amounts, i.e. when the ratio is less than about 4: 1, tends to decrease the flame retardant effect, the unnecessary polyol, in

  excess, serving as fuel to the flame.

  Among the thermoplastic resins in which the flame retardant additive composition described herein is useful are thermoplastic resins that are blow moldable, extrudable and injection moldable. We can

  more particularly, among these resins, polyole-

  like polyethylene, polypropylene, poly-

  styrene, polyvinyl chloride, polybudatiene, etc., polycarbonate, polyamide, polyester, and

  poly (ethylene terephthalate), poly (terephthalate

  butylenephthalate), poly (cycloheptetraphthalate)

  hexanedimethanol), etc .; poly (oxyphenylene); a poly-

  imide, polyacrylate, polyether; an epoxy resin; etc. The present invention is particularly interesting

  for thermoplastics having a temperature

  melting point greater than about 150 C.

  It is preferable to add per 100 parts by weight of thermoplastic resin, from about 2 to about 30

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  parts by weight of flame retardant additive. More preferably, from about 10 to about 25 parts by weight of flame retardant additive per 100 parts by weight of

thermoplastic resin.

  As mentioned above, the flame retardant additive must contain a silicone oil, a silicone resin, a gas-producing agent and optionally a polyol. With regard to the silicone oil content,

  silicone resin and gas producing agent, the ad-

  The flame retardant composition will contain from about 20 to about 60% by weight of silicone oil, from about 10 to about 40% by weight of silicone resin, and from about 20 to about 60% by weight of the silicone producing agent. gas. The flame retardant additive should preferably contain from about 30 to about 50% by weight of silicone oil, from about 15 to about 30% by weight of silicone resin and from about 30 to about 50% by weight.

weight of agent producing gas.

  In the practice of the present invention, the flame retarded compositions can be prepared by mixing the thermoplastic resin with the silicone oil, the silicone resin and the gas-producing agent using any mixing or mixing apparatus. homogenization

  conventional, and for example a roll mill, a mixture of

  Banburg or an extruder. The order of addition of each of the components does not appear to be critical and one skilled in the art will be able to optimally perform the mixing operations to meet their particular requirements.

  A recommended method of preparing the composi-

  The flame retardant thermoplastics of the present invention comprises premixing the silicone oil and the MQ resin solution and then removing the solvent, for example by distillation. This will ensure complete dispersion of the resin in the oil. This solution is then combined

  to the remaining constituents by any means

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  to obtain a homogeneous composition (for example, by

  extrusion in a twin screw extruder).

  All the constituents are preferably in the form of a composition at a temperature as low as possible, while of course knowing that the temperature must be at least equal to the melting temperature of the thermoplastic resin. The gas producing agent is heat sensitive and will convert the thermoplastic resin into foam if the melting temperature is too high. Although the

  lessening of foam formation is one of the

  of the present invention, the use of temperature

  Lower courses to form the composition is beneficial for further reducing foam formation. Depending on the particular thermoplastic resin and the gas-producing agent employed, the extrusion temperature may vary between

about 121 C and about 316 C.

  The flame-retarded thermoplastic resin can be molded, extruded, compressed or spun, etc. to form a large number of useful products. These products include coatings, injection molded articles, sheets, webbing fabrics, fibers, and other products. They can find a use

  in conductive wires, housings for

  hair dryers, automobile interiors, fans, motors, pump casings, power tools, electronic equipment cases, etc. Those skilled in the art can easily imagine other uses.

  The rest of the description refers to the examples

  in which all parts are by weight.

Examples 1-5

  Polypropylene (Hercules Pro-fax 6523 resin) was blended at a temperature above its melting temperature with the materials listed in Table I in

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  a Banbury mixer. The resultant material was cut into pellets and injection molded to about

  193 C in the form of test bars UL94.

TABLE I

1 2 3 4 5

  Polypropylene 74.3 78.5 70.8 72.8 72.8

  Magnesium stearate 4,4 3,6 - ---

  Silicone 0.11 6.3 7.1 4.7 5.2 4.8 Silicone resin2 3.2 3.6 2.4 2.6 2.4

Oxide of decab-

diphenyl 6,9 - - - -

Talc 5.0 7.2 - - -

  Ammonium polyphosphate - - 19.7 14.6 14.5 Pentaerythritol - - 4.4 4, 9 5.5

UL-94 V-1 V-1 V-O V-1 V-O

  1. A silanol-terminated polydimethylsiloxane polymer having a nominal viscosity of 90,000 to

150,000 centipoises. -

  2. Silicone resin MQ, with a M / Q ratio of about

0.8 / 1.

  3. (NH4) n + 2 PnO3n + 1 knowing that n = 1000 to 3000, of

Monsanto Company.

4. Pentaerythritol.

26 1 4624

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  Examples 7 and 8 Polypropylene (Hercules Pro-fax 6523 resin) was melted, extruded and cooled in a water bath with the materials listed in Table II. The resulting extrudate was cut into pellets and injection molded at about 193 C in the form of test plates.

UL-94.

TABLE II

6 7

Polypropylene 72.8 72.8

Silicone oil 4.8 ---

2.4 silicone resin ---

  Ammonium polyphosphate 14.5 14.5 Pentaerythritol 5.5 5.5 Observation of the extrudate with little foam much of the naked eye foam, surface

Complicated

UL-94 V-1 burned

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Claims (27)

  1. fireproof composition characterized in that it comprises:   (A) 100 parts by weight of a thermoplastic resin   and (B) from about 2 to about 30 parts by weight of a flame retardant additive comprising:   (i) from 20 to 60% by weight of a silicone oil cone;   (ii) from 10 to 40% by weight of a silicone resin   and (iii) from 5 to 60% by weight of a gas producing agent selected from the group consisting of   compounds containing both phosphorus   phore and nitrogen or a mixture of   containing phosphorus with placed with nitrogen.   2. Composition according to claim 1, characterized   in that the flame retardant additive further contains: (iv) a polyol in a weight ratio to the gas producing agent of about 1/9 and about 1/5.   3. Composition according to claim 1, characterized   in that the thermoplastic resin is a polyole- Fine.   4. Composition according to claim 1, characterized   in that the silicone oil is a substantially linear polydimethylsiloxane polymer having a   viscosity between about 90,000 and 150,000 centi- poises at 25 C.   5. Composition according to claim 1, characterized   in that the silicone resin is a MQ resin composed of monofunctional units M having the average formula R 3 Si 0.5 and tetrafunctional units Q having the average formula SiO 2 and having an average ratio - 15 -   from about 0.3 to 4.0 M units per Q unit.   6. Composition according to claim 1, characterized   in that the gas-producing agent is a compound   containing both phosphorus and nitrogen.   7. A composition according to claim 6, characterized in that the gas generating agent is selected from the group consisting of ammonium polyphosphates, ammonium phosphates, ammonium pyrophosphates, ammonium phosphites. -, ammonium hypophosphates,   ammonium hypophosphites, and ammonium metaphosphates.   8. Composition according to claim 1, characterized   in that the gas-producing agent is a mixture of phosphorus-containing compounds and nitrogen-containing compounds.   9. Composition according to claim 1, characterized   in that the flame retardant additive is present in an amount of from about 10 to about 25 parts by weight.   weight per 100 parts by weight of thermoplastic resin.   10. Composition according to claim 2, characterized   in that the polyol is selected from the group consisting of   killed by pentaerythritol, dipentaerythritol, tripenone   taerythritol, pentitols, hexitols and saccharides.   11. flame retardant additive characterized in that it comprises:   (i) from 20 to 60% by weight of a silicone oil cone;   (ii) from 10 to 40% by weight of a silicone resin   and (iii) from 5 to 60% by weight of a gas producing agent selected from the group consisting of   compounds containing both phosphorus   phore and nitrogen or a mixture of   poses containing phosphorus with placed with nitrogen.   12. Composition according to claim 11, characterized - 16 -   characterized in that the flame retardant additive further contains: (iv) a polyol in a weight ratio to the gas producing agent of about 1/9 and about 1/5.   13. A composition according to claim 11, characterized in that the silicone oil is a substantially linear polydimethylsiloxane polymer having a   viscosity between about 90,000 and 150,000 centi- poises at 25 C.   14. Composition according to claim 11, characterized   characterized in that the silicone resin is a MQ resin composed of monofunctional units M having the average formula R 3 SiO 0.5 and tetrafunctional units Q having the average formula SiO 2 and having an average ratio of about 0.3 to 4 , 0 patterns M per Q pattern.   15. Composition according to claim 11, characterized   characterized in that the gas-producing agent is a compound   containing both phosphorus and nitrogen.   16. Composition according to claim 15, characterized   characterized in that the gas generating agent is selected from the group consisting of ammonium polyphosphates, ammonium phosphates, ammonium pyrophosphates, ammonium phosphites, ammonium hypophosphates, sodium hypophosphites, and the like. ammonium of ammonium metaphosphates and monoammon phosphites.   17. Composition according to claim 11, characterized   characterized in that the gas-producing agent is a mixture of phosphorus-containing compounds and compounds containing nitrogen.   18. Composition according to claim 12, characterized   in that the polyol is selected from the group consisting of   characterized by pentaerythritol, dipentaerythritol, tripentaerythritol, pentitols, hexitols and saccharides.   19. Process for fireproofing a thermosetting resin   plastic characterized in that it comprises the steps of: - 17 -   (A) melt blending of the thermosetting resin   plastic with a flame retardant additive comprising:   (i) from 20 to 60% by weight of a silicone oil   cone; (ii) from 10 to 40% by weight of a silicone resin and (iii) from 5 to 60% by weight of a gas producing agent selected from the group consisting of   compounds containing both phosphorus   phore and nitrogen or a mixture of   poses containing phosphorus with placed with nitrogen.   20. Process according to claim 19, characterized   in that the melting temperature is between viron 121 C and 316 C.   21. The method of claim 19, characterized in that the flame retardant additive further contains: (iv) a polyol in a weight ratio to the gas producing agent of between about 1/9 and about 1/5.   22. The method of claim 19, characterized   in that the silicone oil is a polydimide polymer   essentially linear methylsiloxane having a   viscosity between about 90,000 and 150,000 centi- poises at 25 C.   23. The method of claim 19, characterized in that the silicone resin is a MQ resin composed of monofunctional units M having the average formula R3Sio 0.5 and tetrafunctional units Q having for   mean formula SiO2 and having an average ratio of   0.3 to 4.0 M units per Q unit; 24. The process as claimed in claim 19, characterized in that the agent producing gas is a compound containing   both phosphorus and nitrogen.   25. The method of claim 24, characterized - 18 -   in that the gas generating agent is selected from the group consisting of ammonium polyphosphates, ammonium phosphates, ammonium pyrophosphates, ammonium phosphites, ammonium hypophosphates, hypophosphites of ammonium and ammonium metaphosphates. 26. Process according to claim 19, characterized   in that the gas producing agent is a mixture of compounds   poses containing phosphorus and compounds containing nitrogen. 27. Process according to claim 21, characterized in that the polyol is chosen from the group consisting of   pentaerythritol, dipentaerythritol, tripentaerythene   thritol, pentitols, hexitols and saccharides.