A method of obtaining self-extinguishing expandable polystyrene

 

(57) Abstract:

The invention relates to the chemistry of polymers, namely, to obtain self-extinguishing expandable polystyrene, which is widely used as heat and sound insulation material in construction, including public buildings, as well as for making furniture, packing, etc., Describes a method of obtaining self-extinguishing expandable polystyrene by two-step water-suspension polymerization of styrene in the presence of the flame retardant and stabilizer suspension selected from the group consisting of freshly prepared tricalcium phosphate with the addition of secondary alkylsulfate sodium and solution of polyvinyl alcohol with residual acetate groups of 10 - 14%, including in the first stage suspension polymerization of styrene with mechanical stirring in the presence of benzoyl peroxide, and perhaps tertbutylbenzene, the introduction of a blowing agent and complete the polymerization in suspension in the second stage. The method is characterized by the fact that in the process of polymerization, which is carried out in the presence of a molecular weight regulator, support the value of P = M JKqL in the range of 3.0 to 6.3 where M is the concentration of the molecular regulator stage polymerization wt.% q is the viscosity of the prepolymer of styrene in the first stage polymerization in Fordwich, s, L - coefficient taking into account the type stirrer, equal to 1 for blade mixer and 5,33 for impeller stirrer, and a flame retardant injected in the first stage polymerization in the original reaction mixture. A blowing agent is injected before the second stage polymerization. The technical result - obtaining self-extinguishing expandable polystyrene with improved processability while maintaining a high level of physical and mechanical properties. table 1.

The invention relates to polymer chemistry, in particular the production of self-extinguishing expandable polystyrene (EPS).

Widespread use of polystyrene in construction, including public buildings, as well as for making furniture, packing, etc. requires the use of self-extinguishing materials. To obtain self-extinguishing materials in polymers injected substances that slow or completely suppress their combustion - flame retardants. Effective flame retardants for CHD are substances containing not less than 70% halogen (bromine or bromine and chlorine) and having a decomposition temperature in the range 180 - 200oC. To such substances include hexabrominated, intermunicipality etc.

The most effective is the introduction of the flame retardant in the polymer in the process of obtaining beads UPU, as in this case, the flame retardant is evenly distributed in the polymer.

A method of obtaining self-extinguishing EPS (tiled application Germany N 3347279, MKI C 08 F 12/08, 1985) by water-suspension polymerization of styrene in the presence of benzoyl peroxide and tertbutylbenzene, flame retardant, for example, 1,2,5,6,9,10-hexabromocyclododecane and polyethylene wax with a molecular mass (mm) 1000 - 4000 with the introduction of the stabilizer suspension of tricalcium phosphate for achieving the conversion of styrene 40 - 74 wt.% and a blowing agent (a mixture of n-pentane and isopentane) conversion of styrene 50 - 90%. After the introduction of a blowing agent process is complete in suspension at a temperature of 90 - 110oC. the flame Retardant is used in an amount of 0.4 to 0.8% by weight of styrene. Polyethylene wax is injected to reduce the water content in the beads, improving the cellular structure of the foam. To this end, the initial reaction mixture (styrene with additives and water) is heated to 80oC and kept at this temperature under stirring at least 1-2 hours, after which start the polymerization.

The reaction mass containing foro arrivat at this temperature for 6.5 hours, then type stabilizer suspension (tricalcium phosphate) and conduct the polymerization prophetic 4 hours; introducing a blowing agent and maintain the reaction mass is still 6.5 hours at a temperature of 90oC, raise the temperature to 110oC and maintain it for another 4 hours.

Thus, the total duration of the process, given the whole procedure is over 24 hours. Peniscola obtained from self-extinguishing UPU described method has a thin homogeneous structure, but too much of the duration of the polymerization process makes this method uneconomical.

Also known is a method of obtaining self-extinguishing EPS (U.S. patent N 4407977, NCI 521 - 90, 1983) by water-suspension polymerization of styrene dissolved additives: flame-hexabromocyclododecane (0.75 wt. %) and (C10-C14-epoxyalkanes (0,005 - 0,01 wt.%), used to improve the cellular structure of proistemi and reduce shrinkage.

The method includes the following stages:

- water suspension polymerization of styrene under stirring without the addition of stabilizer suspension, but in the presence of a flame retardant, epoxyalkanes, benzoyl peroxide and tertbutylbenzene the next time temperature% aqueous solution of polyvinyl alcohol with a saponification number of 140, and continuing the polymerization at 90oC for 2 hours;

- the introduction of a blowing agent and the completion of the polymerization in suspension while heating the reaction mass to 120oC for 1 hour and holding at that temperature for 6 hours. The polymerization cycle is 12 - 13 hours.

The resulting beads retardant EPS processing in Peniscola gives a uniform cellular structure, has good adhesiveness of their particles. However, the resulting beads EPS before processing it was necessary to dissipate, he has a wide particle size distribution. Sieving of EPS beads is more energy-intensive operation, and utilization of regional factions (too large and especially dust) is rather complicated due to the presence of a blowing agent. About the recycling of the boundary fractions of EPS beads is discussed in several works (see, for example, U.S. patent N 4433108, 1984 or accepted application Japan N 58-3553, 1983), but usually these fractions go to waste.

The closest in technical essence and the achieved effect to the claimed method is a method according to the patent of Russian Federation N 1702663 (MCI C 08 F 212/08, publ. 27.10.96, B N 30), according to which self-extinguishing EPS of poluchyenii, including in the first stage polymerization of styrene in the presence of benzoyl peroxide (0.2 wt.%) and tertbutylbenzene (to 0.15 wt.%) to conversion of styrene 25 - 47 wt.%, the introduction of the flame retardant and a blowing agent and the completion of the polymerization in suspension in the second stage polymerization. As a stabilizer suspension using freshly tricalcium phosphate with the addition of calcium carbonate, which is injected in the first stage polymerization, and the secondary alkylsulfate sodium introduced into the suspension with the conversion of styrene 25 - 47 wt.% In the first stage polymerization process is carried out with mechanical stirring at 80 - 82oC for 2 - 2.5 hours; after loading of flame retardant dissolved in styrene, and load secondary alkylsulfate sodium, which is introduced to increase the stability of the suspension is injected foaming agent - isopentanol faction, raise the temperature of the reaction mass to 81 - 83oC and carry out the second stage of polymerization in suspension at the following temperature conditions: exposure at 81 - 83oC - 5 hours, rise of temperature up to 130oC for 3.5 hours with a speed of 13oC per hour, holding at 130oC - 2 hours. As a result of polymerization get beads samozatrudnionych fractions of 0.1 wt.%, the relative viscosity of 1.85, residual styrene of 0.05 wt.% When the apparent density 20 kg/m3destructive bending stress is 2.8 kgf/cm2. The duration of the cycle of polymerization of 12 - 13 hours. Obtained in accordance with the prototype (patent RF N 1702663) self-extinguishing EPS has a fairly high physical-mechanical properties, a low content of fine fractions in the polymer beads; the duration of the process of its synthesis satisfactory.

However, during industrial processing into products such UPU, having a relative viscosity of more than 1.8, there is a series of technical difficulties: increased time preuspeiania and formation, increased consumption of steam, there is the undesirable increase in the apparent density of the product.

The technical result, which provides the inventive method, is to obtain self-extinguishing EPS with improved processability while maintaining a high level of physical and mechanical properties.

This technical result is achieved due to the fact that the method of obtaining self-extinguishing EPS by two-step water-suspension polymerization of styrene in the presence of Antip the elderly stirring in the presence of benzoyl peroxide and, perhaps tertbutylbenzene, to conversion of 30 to 45 wt.%, the introduction of the foaming agent and the completion of the polymerization in suspension in the second stage, in the process of polimerizaciya carried out in the presence of a molecular weight regulator, support the value of P= MJKqL in the range of 3.0 to 6.3 where M is the concentration of the regulator mm, equal to 0.01 to 0.04 wt.%; J - concentration benzoylperoxide equal to from 0.25 to 0.30 wt.%; K - conversion of styrene in the first stage polymerization, wt.%; q is the viscosity of the prepolymer of styrene in the first stage polymerization in Fordwich, C; L - coefficient taking into account the type stirrer, equal to 1 for blade mixer and 5,323 for impeller stirrer, and the flame retardant is introduced into the initial reaction mixture in the first stage polymerization.

As a stabilizer suspension in the proposed method using freshly tricalcium phosphate, obtained by merging the solutions of trisodium phosphate and calcium chloride in the presence of calcium carbonate with the addition of secondary alkylsulfate sodium. This freshly tricalcium phosphate is injected at the first stage, and the secondary alkylsulfate sodium added to a suspension of achieving the conversion of styrene 30 to 45 wt.% before the introduction of the foaming agent.

In kajtoch acetate groups (solver). In this case, the first stage polymerization is conducted without stabilizer suspension and solver enter before submitting a blowing agent. EPS obtained in the presence of Solwara, can not be subjected to a surface treatment before processing.

As a flame retardant can be used a known substance containing not less than 70% of bromine or bromine and chlorine and having a decomposition temperature in the range 180 - 200oC, such as hexabromocyclododecane, tetrabromobisphenol and others. Fire retardant take in the amount of 0.4 to 0.8% by weight of styrene, best of 0.6 - 0.7 wt.% Together with the flame retardant in the styrene is usually injected flame retardant synergist - peroxide does not decompose at the temperature of polymerization, such as dicumylperoxide. The synergist take in the amount of ~0,2% by weight of styrene.

As a blowing agent in the present method can be used pentane, isopentane mixture with pentane or isopentane isopentane run distillation of crude oil. A blowing agent is injected in an amount of 5% to 8% by weight of styrene before the second stage polymerization. As the regulator of mm, you can use the well-known regulators mm, such as mercaptans dimer or trimer of alpha-methylstyrene and other, preferably dimer Alf is - and sweetestrossie.

Granulometric composition of the EPS beads, physico-mechanical properties obtained UPU and its products was determined in accordance with OST 6-05-202-83E.

The viscosity of the prepolymer at Fordwich was determined as follows. Upon reaching the desired conversion of the reactor was selected sample of the reaction mass; in the absence of mixing selected reaction mass is stratified, then the oil phase is separated and determine its viscosity Fordwick (at the time of rise of the bubble) in C.

The following examples illustrate the present invention.

Example 1. Getting self-extinguishing foaming of polystyrene with an average diameter of beads 1,4 - 1,5 mm

In the reactor container 11 m3equipped with paddle stirrer, download styrene in the amount of 6.4 m3(5760 kg), include a stirrer and with constant stirring (30 rpm) load benzoyl peroxide in the amount of 0.30 wt.% (18.6 kg), dicumylperoxide in the amount of 0.20 wt.% (12,4 kg), tertbutylbenzene in the amount of 0.15 wt.% (9.3 kg), hexabromocyclododecane in the number of 0.67 wt.% (41,5 kg) and the first portion of the dimer of alpha-methylstyrene in an amount of 0.005 wt.% (0,310 kg). After 15 min in the reactor pumped prepared and heated to 8 is obtained by merging salt solutions of trisodium phosphate (0.56 wt.%) and calcium chloride (0,54 wt.%) in demineralized water and the addition of calcium carbonate (0.13 wt.%). The reaction mass is heated to 80-82oC for 30 minutes, the polymerization Process is carried out at 80-82oC for 2.5 h to conversion of 41%, the viscosity of the prepolymer is 25 C (method Fordwich.) Upon reaching the specified degree of conversion of the speed of the mixer was lowered to 28 rpm and was charged to the reactor a mixture of secondary sodium alkyl sulphates of 0.002 wt.% (400 ml of 30% aqueous solution). Module baths (volume ratio of organic phase and water) is 5: 3. Then in the resulting stable suspension is injected second portion of the dimer of alpha-methylstyrene in an amount of 0.005 wt.%. (0,310 kg), the unit is sealed and load it with a blowing agent - isopentanol the fraction of 7%wt. (600 l) for 30 minutes Raise the temperature to 83oC for 30 minutes Then the polymerization is carried out at the following temperatures: exposure at 82oC - 5 h; temperature rise to 130oC for 3.5 h with a speed of 13oC per hour; exposure at 132oC - 2 h

Then the contents of the apparatus is cooled to 40oC, unload in the buffer tank, where it is acidified to pH of 2.5-3.0 for the destruction of tricalcium phosphate, diluted with desalted water to a ratio of the solid phase and the liquid 1:2,1, after chekki the composition of the beads and physico-mechanical properties of the project in example 1 and all the following examples are presented in the table.

Example 2. Getting self-extinguishing expandable polystyrene with an average diameter of beads of 2.8-3.0 mm

The process is conducted as described in example 1, but the dimer of alpha-methylstyrene in the number 0,020%wt.(1.24 kg) administered a single dose immediately after loading of styrene in the apparatus. The process is continued until the conversion of 43%, while the viscosity of the prepolymer is 22 C. the value of the parameter P=5,68.

Example 3. Getting self-extinguishing expandable polystyrene with an average diameter of beads 1,1 - 1,3 mm

In the reactor, with a capacity of 11 m3equipped with paddle stirrer, download styrene in the amount of 4.5 m3(4050 kg), include a stirrer and with constant stirring (30 rpm) load benzoyl peroxide in the amount of 0.25 wt.% (10,9 kg), dicumylperoxide in the amount of 0.20 wt.% (8,8 kg), hexabromocyclododecane in the number of 0.67 wt.% (29,4 kg) and the first portion of the dimer of alpha-methylstyrene in an amount of 0.015 wt. % (0,660 kg). After 15 min in the reactor ends of demineralized water in an amount of 2.5 m3start temperature rise to 80oC for 1 h, the polymerization Process is carried out at 80 - 82oC for 2 h before the conversion of 45%, the viscosity of the prepolymer is 15 C. Upon reaching a specified degree of conversion in rlci to 10 rpm and start downloading aqueous solution of Solwara in the amount of 2.5 m3(with a concentration of 0.35 - 0.40 wt.%). After loading salwar speed of the stirrer was increased to 28 rpm for 4 min to produce emulsification (until the drops of oil phase of the desired size). Then the speed of the mixer was lowered to 22 rpm and loads of tertbutylbenzene in the amount of 0.18 wt.% (7.9 kg). After 50 minutes after emulsification reactor seal. Charged to the reactor foaming agent - isopentanol faction in the amount of 7.6 wt.% (460 l) within 30 minutes After the polymerization process continues at the following temperature: 80oC - extract 1.5 h (at the end of the exposure turnover stirrers are translated at 30 Rev/min); temperature rise to 85oC - 0.5 h; exposure at 85oC - 0.5 h (at the end of the shutter speed stirrer increase of 35 R/min); temperature rise 115oC - 2.5 hours; exposure at 115oC - 3,5 hours

Then the contents of the apparatus is cooled to 40oC, unload in the buffer vessel, diluted with desalted water to a ratio of the solid phase and the liquid 1 in 2.5, then centrifuged and the obtained polystyrene beads are dried. The value of the parameter P=5,06.

Example 4 (control). Getting self-extinguishing foaming of polystyrene with an average diameter is thus the viscosity of the prepolymer reaches 27 with the conversion of 39%. The value of the parameter P=0.

Example 5 (control). Getting self-extinguishing expandable polystyrene with an average diameter of beads 1,1 - 1,3 mm

The process is conducted as described in example 3, but in the absence of the dimer of alpha-methylstyrene, and benzoyl peroxide download in the amount of 0.3 wt.% While the viscosity of the prepolymer reaches 30 with the conversion of 39%. The value of the parameter P= 0.

The table shows that the index distribution of the diameter of the beads on the size of the worse and the amount of flour fractions are much higher than for the product according to example 3. At the same time, despite the high value of the relative viscosity and a large apparent density of 22 kg/m3the rate of tensile strength in bending is at the lower tolerance limit (for a given apparent density).

Example 6 (control). Getting self-extinguishing expandable polystyrene with an average diameter of beads 1,1 - 1,3 mm

The process of conducting, as described in example 3, but the dimer of alpha-methylstyrene load in the amount of 0.005 wt.% (0.22 kg) in one stage, immediately after loading of styrene in the device (as in example 2), and benzoyl peroxide download in the amount of 0.3 wt.% (13.1 kg). While the viscosity of the prepolymer reaches 27 when it is somaticheskogo composition (especially a reduced amount of particulate fractions), but the physico-mechanical properties of the product is not significantly improved.

Example 7 (control). Getting self-extinguishing expandable polystyrene with an average diameter of beads 1,4 - 1,5 mm

The process is carried out as in example 1, but instead of a dimer of alpha-methylstyrene use n-laurylsarcosine. While the viscosity of the prepolymer is 12 and a conversion of 48%. The value of the parameter P=1,73.

The table shows that the average size of the beads does not fall within the defined range (1.4 to 1.5 mm), significantly increases the dispersion diameter of the beads; deteriorating physical-mechanical properties, increases the residual monomer content.

Example 8. Getting self-extinguishing expandable polystyrene with an average diameter of beads 1,4 - 1,5 mm

The process is carried out as in example 1, but the total number of dimer of alpha-methylstyrene is 0,040 wt. % and benzoyl peroxide 0.25 wt.% While the viscosity of the prepolymer is 15 with a conversion of 42%. The value of the parameter P=6,30.

Example 9 (control). Getting self-extinguishing itsenaisilta polystyrene with an average diameter of beads 1,4 - 1,5 mm

The process is carried out as in example 8, but the total number of dimer of alpha-metea P=6,58.

The table shows some deterioration of the dimensional distribution of the beads, as well as the tendency to deterioration of strength in bending (located on the lower limit for the density 15 kg/m3).

Example 10. Getting self-extinguishing expandable polystyrene with an average diameter of beads 1,1 - 1,3 mm

In the reactor container 11 m3equipped with impeller stirrer, loads of components, as described in example 3. The polymerization process is carried out at 80 - 82oC for 3 hours to a conversion of 30%, while the viscosity of the prepolymer is 5 C. Upon reaching a specified degree of conversion in the reactor load the second portion of the dimer-methylstyrene (as described in example 3) and start downloading aqueous solution of Solwara in the amount of 2.5 m3(concentration 034 wt. %). After loading solution Solwara increase speed of mixer until 50 Rev/min and 1.5 min again reduced to 30 rpm are used for visual control of droplet size mulgirigala oil phase. Then charged to the reactor, tertbutylbenzene as in example 3. After loading tertbutylbenzene the reactor is pressurized to create a nitrogen pressure of 0.9 MPa, enter isopentanol fraccia temperature rise to 115oC for 3.2 hours and carry out exposure at 115oC for 3.5 hours. Next, the process is conducted as described in example 3. The value of the parameter P=6,00.

Obtained in the examples and self-extinguishing EPS has a Flammability class V= 0 by the method of UL-94, that is, immediately fades out after removal of the flame.

As can be seen from the table, the inventive method allows to obtain self-extinguishing EPS with a relative viscosity in the range of values 1,68 - 1,78, with the processing in penisgay high strength indicators: when the apparent density of proistemi 15 kg/m3Flexural strength of 0.70 to 0.75 kgf/cm2when the apparent density 20 kg/m3Flexural strength 2,90 kg/cm2. Obtained by the claimed method EPS beads has a narrow particle size distribution, pulverulent fraction missing or keeping them small. The content of residual styrene beads low (0.02 to 0.03 wt. %), which has a positive effect on the mechanical and operational properties of polymers and Pinesdale. If the process is carried out in conditions where the value of the parameter P is outside the claimed range (3,00 - 6,30), the strength characteristics of proistemi below even then, to whom and by two-step water-suspension polymerization of styrene in the presence of the flame retardant and stabilizer suspension selected from the group consisting of freshly prepared tricalcium phosphate with the addition of secondary alkylsulfate sodium and solution of polyvinyl alcohol with residual acetate groups of 10 - 14%, including in the first stage suspension polymerization of styrene with mechanical stirring in the presence of benzoyl peroxide, and perhaps tertbutylbenzene, the introduction of a blowing agent and the completion of the polymerization in suspension in the second stage, characterized in that the polymerization process carried out in the presence of a molecular weight regulator, support

P = M J K q L

in the range of 3.0 to 6.3

where M is the concentration of the regulator of molecular weight equal to 0.01 to 0.04 MSS.%;

J - concentration benzoyl peroxide equal to from 0.25 to 0.30 wt.%;

K - conversion of styrene in the first stage of polymerization equal to 30 to 45 wt.%;

q is the viscosity of the prepolymer of styrene in the first stage polymerization in fordwich, S.;

L - coefficient taking into account the type stirrer, equal to 1 for blade mixer and 5,33 - for impeller stirrers,

moreover, the flame retardant additive is injected in the first stage polymerization in the original reaction mixture, and a blowing agent is injected before the second stage polymerization.

 

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FIELD: organometallic polymerization catalysts.

SUBSTANCE: invention relates to alkylcobalt(III) complexes with tridentate Schiff's bases wherein alkyl ligand contains functional group, notably hydroxyl, carboxyl, or amino group, in accordance with general formula:

(I),

in which W represents two-moiety unsaturated hydrocarbon bridge group expressed by formula =C(H)=C(CH3)- (propene-1,2-diyl) or o-C6H4 (o-phenylene); X is OH, NH2 or COONa; Y monovalent anion: Cl-, Br-, NO3- or ClO4-; and Z polymethylene bridge group (CH2)n, wherein n=3-11 when X = OH or NH2 and n=2-11 when X = COONa. The complex are used as initiators of emulsion polymerization and copolymerization of diene and vinyl monomers to produce reactive bifunctional oligomers and polymers with terminal functions, which oligomers and polymers are suitable for further conjugation with corresponding reagents.

EFFECT: extended choice of specific polymerization catalysts.

3 tbl, 30 ex

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