GB2095688A - Preparation of a polymeric substance - Google Patents

Abstract

A process for the preparation of a polymeric substance or a liquid product containing a polymeric substance, comprises at least two unit steps of polymerizing a polymerizable monomer or a mixture of at least two monomers copolymerizable with each other in which cold heat, obtained by an absorption type refrigerating method using polymerization heat generated during polymerization and/or remaining heat from other unit steps as the heat source, is used as the cold heat source for at least one other unit step that requires cooling below normal ambient temperature. Such a process reduces the amount of energy required to produce polymeric substances.

Description

SPECIFICATION Process for preparation of a polymeric substance or 3 liquid product containing a polymeric substance The present invention relates to a process for the preparation of a polymeric substance of a solution, suspension or emulsion containing a polymeric substance (hereinafter referred to as "polymeric substance" inclusively) in which saving of energy is attained.

A polymeric substance is formed by homopolymerization of an organic compound or by copolymerization of at least two organic compounds or by repetition of reaction of condensing molecules of at least one organic compound while forming relatively low-molecularweight by-products such as for example water, hydrogen chloride, ammonia, alcohol and carbon dioxide. The process for preparing a polymeric substance by a polycondensation reaction is wellknown and has been practically carried out on a large scale. It is known that most of these homopolymerization, copolymerization and polycondensation reactions (hereinafter referred to as a "polymerization reaction" inciusively) are highly exothermic reactions.The process for the preparation of a polymeric substance, which is based on the above-mentioned principle, comprises at least two unit steps such as the step of storing the starting material and homogeneously mixing an additive into the starting material, the polymerization step, the step of removing the unreacted substance of other unnecessary substance, the step of recovering the removed unnecessary substance and the moulding or pelletizing step. Moreover, at the polymerization step at least.one polymerization vessel is required and in many cases in a continuous process, two or more polymerization vessels are arranged in parallel or in series.When the polymerization reaction is carried out according to conventional procedures, in order to remove the polymerization heat or to maintain the reaction temperature at a desirable level, heat transfer surfaces are arranged on the inner and outer sides of the polymerization vessel and the reaction mixture is cooled by a cooling medium such as for example cooling water, while the polymerization heat transferred to the cooling medium is not effectively utilized but discarded into the surrounding environment as well as the remaining heat from other unit steps that requires cooling to a level approximating to normal ambient temperature. In most of the unit steps, cooling below the normal ambient temperature is required.For example, some of the starting organic compounds (hereinafter referred to as "monomers") to be used for the polymerization reaction are slightly polymerized even at the normal ambient temperature and advance of this undesirable polymerization is prevented by the addition of a polymerization inhibitor or by maintaining such monomer at a temperature lower than the normal ambient temperature.

Furthermore, in the case where it is difficult to complete the polymerization reaction, in order to remove and recover a part or all of the unreacted monomer or the additive, the reaction mixture is heated under a pressure equal to or lower than the polymerization pressure to gasify the unreacted monomer or additive and separate it from the reaction product. The vapour formed by gasification is cooled below the normal ambient temperature and condensed and recovered. As the conventional cold heat-generating method customarily adopted for lowering the temperature below the normal ambient temperature, there is ordinarily adopted a method using a compression type refrigerator requiring energy to be supplied -from the outside.

In accordance with the present invention there is provided a process for the preparation of a polymeric substance in which the cold heat source, which is necessary for the above mentioned reason, is generated by an absorption type refrigerating method using the polymerization heat produced during the polymerization reaction and/or the remaining heat produced from other unit steps as the heat source and this cold heat source is utilized so that energy to be introduced from the outside in the conventional method for a compression type refrigerator becomes unnecessary or at least is drastically reduced.

In the accompanying drawings: Fig. 1 is a flow diagram illustrating the principle of the present invention, and Fig. 2 is a diagram illustrating one embodiment of the process of the present invention.

In the drawings the reference numerals have the following significance: 1: pipe; 2: polymerization vessel; 3: heat transfer surface of polymerization vessel; 4: pipe; 5: volatile component remover; 6: heat transfer surface of volatile component remover; 7 and 8: pipes; 9: condenser; 10: heat transfer surface of condenser; 11, 12 and 13: pipes; 14: heat exchanger; 1 5 and 16: pipes; 17: absorber; 1 8 and 19: pipes; 20: pump; 22, 22, 23, 24a, 24b, 25a and 25b: pipes; 26, 27 and 28: pipes; 29: distilling device; 30: pipe; 31: cooler; 32: pipe; 33: pump; 34: heat exchanger; 35, 37 and 38: pipes; 40: compressor; 41: cooler.

The principle of the present invention will now be described with reference to Fig. 1, in which in the continuous preparation of a polymeric substance, the cold heat is generated by the absorption refrigerating method utilizing as the heat source the polymerization heat and the remaining heat possessed by the polymeric substance after removal of the volatile component by heating the polymerization product under reduced pressure. In Fig. 1, reference numeral 1 represents a starting monomer feed pipe. A starting monomer and any desirable auxiliary starting materials such as for example a polymerization catalyst, a molecular weight modifying agent, a solvent and additives (e.g.

plasticizers, dyestuffs and pigments) are fed to a polymerization vessel 2 through this pipe 1 and/or a desirable number of pipes (not shown) leading into the polymerization vessel 2. In Fig. 1, only one polymerization vessel 2 is shown, but in either a batchwise polymerization process or a continuous polymerization process, two or more polymerization vessels may be arranged in parallel or in series. All these arrangements are representatively indicated by this one reaction vessel 2, and the process of the present invention can be carried out irrespective of these arrangements of the polymerization vessels. In the interior of the polymerization vessel 2, agitation is ordinarily performed by an agitator (not shown).A heat transfer surface 3 for removal of the polymerization heat is attached to the polymerization vessel 2, and the cooling medium and absorbing liquid used for the absorption type refrigerating method described hereinafter are heated through this heat transfer surface 3 and simultaneously the polymerization heat is removed to maintain a desirable temperature in the polymerization vessel.The polymerization product in which the polymerization reaction has been completed is transported to a volatile component remover 5 having a heat transfer surface 6 through a pipe 4, and in the volatile component remover 5, the reaction product is heated through the heat transfer surface 6 by heat conducted from an exterior heat source via a pipe 7 under a desirable pressure substantially equal to or lower than the pressure in the polymerization vessel, whereby the unpolymerized monomer and volatile substances contained in the product are removed in the form of vapours.The volatile components, gasified by heating, are fed through a pipe 8 to a condenser 9 where a pressure substantially equal to the pressure in the volatile component remover is maintained in the condenser 9. the gasified volatile components are cooled by the cold heat source supplied through a pipe 11 via a heat transfer surface 10 attached to the condenser 9 from the absorption type refrigerating method. The condensate is withdrawn through a pipe 12 and added to the starting monomer or fed to a desirable step such as for example a refining step. On the other hand, the polymerization product from which the volatile components have been removed at the volatile component remover is withdrawn through a pipe 13 and cooled in a heat exchanger 14 in the same manner as in the polymerization vessel.The cooled polymerization product is fed to the next step through a pipe 1 5. in the above-mentioned series of steps, the volatile component removing step 5 is ordinarily divided in a plurality of stages where the temperature and/or the pressure are different, and there is often one condenser for each stage. In Fig. 1, one volatile component remover 5 and one condenser 9 are representatively shown as in the case of the polymerization vessel. In many cases, the polymerization product fed to the volatile component remover 5 through the pipe 4 is a liquid having a high viscosity, and therefore, in order to enhance the effect of removing the volatile components, the heat transfer surface 6 of the volatile component remover is arranged so that the polymerization product flows on the heat transfer surface 6 in the form of a film.In some cases, a step which is not directly relevant to the present invention is disposed between the polymerization vessel 2 and the volatile component remover 5, but such step is omitted in the drawings. In the embodiment illustrated in Fig. 1 , the absorption type refrigerating method is connected to the above-mentioned series of polymerization steps in the following manner. In the known absorption type refrigerating method, there are ordinarily used a cooling medium having a boiling point lower than the normal ambient temperature under atmospheric pressure and an absorbing liquid being capable of dissolving the cooling medium therein and having a boiling point higher by at least 500C than that of the cooling medium under atmospheric pressure.The cold heat source supplied to the heat transfer surface 10 of the condenser 9 through the pipe 11 is the cooling medium which is maintained under reduced pressure. This cooling medium cools and condenses the vapours of the volatile components, which are fed from the volatile component remover 5 through the pipe 8, through the heat transfer surface 10 of the condenser 9, while the cooling medium per se is evaporated in the form of a cooling medium gas. This cooling medium gas is fed to an absorber 1 7 through a pipe 1 6 and in the absorber 1 7 the cooling medium gas is in contact with the absorbing liquid having a low cooling medium content (hereinafter referred to as "poor absorbing liquid") which has been fed to the absorber 1 7 through a pipe 1 8.

Thus, the cooling medium gas is dissolved in the poor absorbing liquid and the absorbing liquid is converted to a rich absorbing liquid having a high cooling medium content. Heat generated during this dissolution is indirectly removed by cooling water at substantially the normal ambient temperature supplied through a pipe 1 9. The rich absorbing liquid formed in the absorber is withdrawn and compressed by a pump 20 and is passed through pipes 21,22 and 23 and branched to pipes 24a and 24b. The rich absorbing liquid passed through the pipe 24a is heated by the polymerization heat through the heat transfer surface 3 of the polymerization vessel while the rich absorbing liquid passed through the pipe 24b is heated by the remaining heat of the polymerization product after removal of the volatile components by the heat exchanger 14.

Both the absorbing liquids are thus boiled and combined in a pipe 26 through pipes 25a and 25b, and the combined absorbing liquid is introduced through pipes 27 and 28 into a distilling device 29 where the rich absorbing liquid is subjected to distillation under substantially the same pressure as the pressure at the outlet of the pump 20. The cooling medium gas in the compressed state is withdrawn from a pipe 30 disposed in the upper portion of the distilling device 29. The cooling medium gas is indirectly cooled in a cooler 31 by cooling water maintained substantially at the normal ambient temperature and the cooling medium gas is thus liquefied.A part of the liquefied cooling medium is used as a reflux liquid on the distilling device 29 through a pipe 32 according to need, while the remaining majority of the cooling medium is used as the cold heat source of the condenser 9 through the pipe 11 as described above. The rich absorbing liquid from which the cooling medium gas is separated in the distilling device 29 is withdrawn in the form of the poor absorbing liquid from the lower portion of the distilling device, and the pressure is reduced and the poor absorbing liquid is recycled to the absorber 1 7 through the pipe 18.

In the case where the polymerization temperature in the polymerization vessel 2 and the temperature of the flow of the polymeric substance running from the volatile component remover 5 through the pipe 13 are relatively high then another heat exchanger 34 below the distilling device 29 and another pump 33 are provided, and the piping system is partially changed so that these members are connected to one another as shown in Fig. 2. The rich absorbing liquid compressed by the pump 20 is supplied to the distilling device 29 through pipes 21 and 35.

In the embodiment shown in Fig. 2, a heating medium which is different from the abovementioned cooling medium, is compressed by the pump 33, passed through pipes 37 and 23, branched into pipes 24a and 24b, heated by the heat transfer surface 3 and heat exchanger 14, passed through the pipes 25a and 25b, respectively, and combined in the pipe 26. In the heat exchanger 34, the combined heating medium heats the bottom portion of the distilling device and the temperature of the heating medium is lowered. The heating medium is recycled through a pipe 38 by the pump 33 to transfer the polymerization heat and remaining heat and to heat the bottom portion of the distilling device 29.

Thus, the polymerization vessel and the remaining heat-generating zone are thermally coupled with the absorption type refrigerating method. If the absorption type refrigerating method is carried out in the mode shown in Fig. 2, occurrence of undesirable reduction of the overall heat transfer coefficient of the heat transfer surfaces, which is due to lowering of the temperature of the polymerization product-contacting sides of the heat transfer surfaces attached to the unit steps acting as the heat source, such as the heat transfer surfaces 3 and 6 and subsequent solidification and sticking of the polymerization product in contact with these heat transfer surfaces, is effectively prevented.In carrying out the absorption type refrigerating method in the series of steps for the production of the polymeric substance, a single absorption refrigerating apparatus adopting the heating methods as shown in Figs. 1 and 2 in combination may be provided for a plurality of unit steps acting as the heat source. On the other hand, the heating method shown in Fig. 1 and the heating method shown in Fig. 2 may be adopted independently for different absorption type refrigerating systems for different unit steps acting as the heat source.

In the process of the present invention, a certain quantity of driving power is necessary for the pump 20 used for the absorption type refrigerating method shown in Fig. 1 or the pump 33 used for the method shown in Fig. 2. However, the quantity of driving power necessary for these pumps is very small and only about 20% to about 40% of the quantity of driving power necessary for obtaining the same quantity of cold heat by using a conventional compression type refrigerating machine. Accordingly, even if driving power for the pump 20 or 33 is supplied from outside of the system, the advantages of the present invention, described hereinafter, are not impaired at all.In the case where the sum of the polymerization heat and the remaining heat as other heat source for the absorption type refrigerating method is in excess of the necessary quantity of cold heat, power is generated by a turbine cooling medium expanding according to the known Rankine cycle utilizing the excess of the heat source, and the above-mentioned pumps are driven by the power so-generated. In this case no driving power needs to be supplied from outside.

The present invention will now be described more specifically. In the embodiment shown in Fig. 2, monomeric styrene is fed at a rate of 4353 Kg/hr to the polymerization vessel 2 through the pipe 1, and in the polymerization vessel, 2,75% of the supplied monomeric styrene is polymerized. In the volatile component remover 5, 25% of the unpolymerized monomeric styrene is heated under high vacuum and the gasified styrene monomer is cooled and liquefied in the condenser 9 at about 20C. Thus, polystyrene is prepared. This process will now be described in detail. As the heating medium to be recycled repeatedly by the pump 33 there is used Dowtherm, and in the absorption type refrigerating method, ammonia is used as the cooling medium and water is used as the absorbing liquid.In order to cool and liquefy the styrene monomer under high vacuum in the condenser 9,216,600 Kcal/hr of the cold heat source maintained at a temperature not higher than --40C is necessary. If a compression type refrigerator to which electric power is supplied from the outside is used for obtaining this cold heat source according to the conventional technique, electric power is consumed at a rate of 60.7 KWH/hr. In contrast, if the sum of the polymerization heat generated by the polymerization reaction conducted at a temperature higher than 1 000C and the remaining heat possessed by the polystyrene liquid left after removal of the unpolymerized monomer by the volatile component remover 5, that is, 562,200 Kcal/hr, is used as the heat source of the absorption type refrigerating method in the abovementioned manner,216,600 Kcal/hr of cold heat at -40C can be produced by the absorption type refrigerating method. The power consumption necessary for the pumps 20 and 33 is 9.24 KWH/hr. Thus about 51 KWH/hr of electric power can be saved. In this embodiment, the production rate of polystyrene is about 3260 Kg/hr, and about 15.7 KWH of electric power can be saved per 1000 Kg of polystyrene and this corresponds to 18% of the power consumption in the conventional technique, that is, about 86 KWH per 1000 Kg of polystyrene.

Needless to say, in the process of the present invention, cooling and liquefaction of the volatile components in the condenser 9 is possible as in the conventional technique.

In the foregoing embodiment, polystyrene is prepared by using monomeric styrene as the starting material. Polymeric substances other than polystyrene can similarly be prepared according to the process of the present invention. For example, there can be mentioned polypropylene, high density polyethylene, low density polyethylene, polyvinyl chloride, polyvinyl acetate, polyacetal, polymethyl methacrylate, polyethelene terephthalate, polycaproiactam, polyacrylonitrile, polymethyl acrylate, polycarbonate, polybutadiene, polyisoprene, polychloroprene, and copolymers of two or more of the constituent monomers of the foregoing polymers.As regards the form of the product, there can be mentioned products which are solid at the normal ambient temperature, such as for example yarns, pellets and plates, and products which are liquid at the normal ambient temperature, such as for example emulsions, suspensions, solutions and pastes. As the process for preparing these polymeric substances from the starting monomers, there can be mentioned the bulk polymerization process explained above with reference to the production of polystyrene, in which an additive giving a diluting effect to the monomer is not used; the suspension or emulsion polymerization process in which a monomer having a low water solubility is polymerized in the state dispersed in water; and a solution polymerization process in which a monomer is diluted and dissolved by a solvent as the additive.Each of these polymerization processes can be carried out in a continuous manner or batchwise. Even if additives having no diluting effect on the polymer, such as for example polymerization catalysts, molecular weight modifying agents, suspension stabilizers and emulsion stabilizers or additives having a diluting effect on the monomer are not added at all, polymerization can be advanced in some cases in these polymerization processes, but in many cases, one or more of these additives are employed.

Specific polymerization conditions to be adopted for the production of the foregoing polymeric substances differ greatly depending on the properties of the starting monomer and the intended use of the polymeric substance obtained.

Generally, however, the polymerization temperature is from -300C to 3000C and the pressure is from as high vacuum as possible to 2000 Kg/cm2 gauge. Moreover, the quantity of heat produced by polymerization greatly differs from one set of circumstances to another Ordinarily, the quantity of heat generated by polymerization accompanied by the formation of by-products, such as for example the polymerization of a vinyl type monomer, is slightly smaller than the quantity of heat produced by polymerization not accompanied by formation of by-products. In the polymerization of vinyl monomers, in many cases, about 22 Kcal of heat is produced per gram-mole of the monomer. This heat is effectively utilized in the present invention.

In the case where the heating or cooling operation is carried out at a unit step other than the polymerization step as described hereinbefore, then the heat generated by such operation can be utilized as the heat source in the present invention as with the polymerization heat. Since according to the present invention, the cooling medium, absorbing liquid and heating medium do not come into contact with the starting monomer, polymerization product and final polymeric substance then, in principle, the present invention can be applied to any process for the production of polymeric substances. In the absorption type refrigerating method used in the present invention, cooling water maintained substantially at the normal ambient temperature shouid be used for the cooling pipe 19 and cooler 31 in the embodiments shown in Figs. 1 and 2.The temperature of cooling water maintained at the normal ambient temperature is often as high as about 40"C in summer, though this temperature differs to some extent according to the district. In the present invention, it is essential that the polymerization heat and other remaining heat used as the heat source for the absorption type refrigerating method should have a temperature higher than the temperature of cooling water maintained substantially at the normal ambient temperature. Accordingly, if the temperature of the polymerization heat and other remaining heat is lower than 550C, the cold heat-generating capacity of the absorption type refrigerating method is reduced.

As the unit step for which the cold heat generated by the absorption type refrigerating method in the present invention is necessary, there can be mentioned, for example, the step of storing a methyl methacrylate monomer, the step of cooling and condensing an evaporated unreacted monomer such as for example monomeric styrene in the above-mentioned case of production of polystyrene and/or a vapour of a solvent used as the diluent; and the step of forming cold air or cooling water of a temperature lower than the normal ambient temperature to be used for quenching a mould article formed by spinning or pelletizing the polymeric substance.

The present invention may be carried out according to basic embodiments as shown in Figs.

1 and 2, and heat exchangers (not shown) may be additionally arranged at desirable positions to increase the quantity of cold heat generated by the absorption type refrigerating method. In such case, heat exchangers are disposed for example, so that, (a) in Fig. 2, the poor absorbing liquid transferred from the distilling device 29 to the absorber 1 7 through the pipe 1 8 is heatexchanged, after departure from the distilling device 29 without reduction of the pressure, with the rich absorbing liquid transferred to the distilling device 29 from the pump 20 through the pipe 21 to cool the poor absorbing liquid and thus heat-exchanged poor absorbing liquid is cooled by heat exchange with cooling water maintained substantially at the normal ambient temperature and then reduced and supplied to the absorber 17, or (b) the cooling medium condensed and liquefied by cooling water maintained substantially at the normal ambient temperature in the cooler 31 is heat-exchanged without reduction of the pressure with the cooling medium gas fed to the absorber 17 through the pipe 1 6 and then reduced and supplied to the heat transfer surface 10 of the condenser 9 through the pipe 11. Accordingly, it will readily be understood that embodiments of the present invention are not limited to those specifically illustrated in Figs. 1 and 2.

The degree of energy-saving attainable in preparing the polymeric substance according to the process of the present invention is highest when the quantity of cold heat obtained, if the polymerization heat and other remaining heat are completely used for the absorption type refrigerating method, is in agreement with the sum of cold heat necessary for all the cold heatrequiring unit steps as in the above-mentioned case of production of polystyrene.If the quantity of cold heat generated is not in agreement with the necessary quantity of cold heat, the degree of energy-saving attainable in the production of the polymeric substance is reduced irrespective of whether the quantity of cold heat generated or the necessary quantity of cold heat is excessive, so far as the ratio of the monomer converted to the polymer to the starting monomer fed (hereinafter referred to as "polymerization ratio") is the same.

In the case where the quantity of generated cold heat is excessive, the scale of the absorption type refrigerating method is reduced so that the quantity of generated cold heat obtained is substantially in agreement with the necessary quantity of cold heat, and the excess of the polymerization heat and other remaining heat is easily discarded in the surrounding environment in the same manner as adopted in the conventional technique or is utilized in the above-mentioned manner.In the case where the quantity of generated cold heat is smaller than the necessary quantity of cold heat, as indicated by dotted lines in Fig. 2, a part of the cooling medium gas fed to the absorber 17 through the pipe 1 6 is sucked and compressed in a compressor 40 driven by power supplied from the outside and cooled and liquefied by cooling water maintained substantially at the normal ambient temperature in a cooler 41, and the liquefied cooling medium is combined, after reduction of the pressure through the pipe 11, with the liquefied cooling medium from the absorption type refrigerating method, whereby the shortage of the quantity of generated cold heat can be compensated. Furthermore, the quantity of generated cold heat can be made equal to the necessary quantity of cold heat according to methods other than the above-mentioned methods.In most processes for the production of polymeric substances, the polymerization heat forms a substantial portion of the sum of the polymerization heat and other remaining heat utilized as the heat source for the absorption type refrigerating method. Accordingly, if the polymerization ratio is increased or decreased to some extent, the quantity of heat source used for the absorption type refrigerating method is greatly increased or decreased, and hence, the quantity of cold heat generated by the absorption type refrigerating method is greatly increased or decreased. Increase or decrease of the polymerization ratio results in decrease or increase of the quantity of cold heat necessary for the condenser 9 in the embodiments shown in Figs. 1 and 2.Accordingly, if the quantity of generated cold heat is not in agreement with the necessary quantity of cold heat, this disagreement can be substantially eliminated by appropriately changing the polymerization ratio of the monomer supplied in the polymerization vessel. This method can be performed very conveniently when a large quantity of polymerization heat is generated as in the case of the polymerization of a monomer having a double bond, and this method is carried out under conditions minimizing the energy consumption. Therefore, this method is especially advantageous. In a batchwise polymerization process, it often happens that the time when the polymerization heat and other remaining heat are generated is not in agreement with the time when cold heat is required.In such case, a lowtemperature cooling medium is formed and stored when the polymerization heat and other remaining heat are generated, and the stored cooling medium is taken out and used when cold heat becomes necessary, as in the conventional technique.

In the present invention, there may be used not only the above-mentioned combination of ammonia as the cooling medium and water as the absorbing liquid but also any of the known cooling medium-absorbing liquid combinations for the absorption refrigerating method. For example, there can be mentioned combinations of waterlithium chloride, water-lithium bromide, ethyl chloride-tetrachloroethane, methylene chloridetetraethylene glycol dimethyl ether and Freon 21 tetraethylene glycol dimethyl ether (the firstmentioned compound in each of these combinations is a cooling medium). The characteristic advantage of the present invention is that the polymerization heat and other remaining heat generated in the production of polymeric substances, which are discarded into the atmosphere or into a natural waterway according to the conventional technique, are effectively utilized as the heat source for the absorption type refrigerating method and the amount of energy required for production of polymeric substances is drastically reduced as described above.

Claims (6)

1. A process for the preparation of a poiymeric substance or a liquid product containing a polymeric substance, which comprises at least two unit steps of polymerizing a polymerizable monomer or a mixture of at least two monomers copolymerizable with each other in which cold heat, obtained by an absorption type refrigerating method using polymerization heat generated during polymerization and/or remaining heat from other unit steps as the heat source, is used as the cold heat source for at least one other unit step that requires cooling below normal ambient temperature.

2. A process according to claim 1 wherein the degree of polymerization of the starting monomer or monomer mixture is increased or decreased so that the quantity of cold heat obtained by the absorption type refrigerating method is substantially equal to the quantity of cold heat necessary for at least one other unit step that requires cooling below normal ambient temperature.

3. A process according to claim 1 or 2, wherein the two monomers are copolymerizable with each other at a temperature of at least 550C.

4. A process according to claim 1,2 or 3, wherein the polymerization is effected in the presence of an additive.

5. A process for the preparation of a polymeric substance or a liquid product containing a polymeric substance substantially as herein described with reference to Fig. 1 of the accompanying drawings.

6. A process for the preparation of a polymeric substance or a liquid product containing a polymeric substance substantially as herein described with reference to Fig. 2 of the accompanying drawings.