DK145183B - PROCEDURE FOR THE PREPARATION OF POLYMERS OR COPOLYMERS OF VINYL CHLORIDE IN INSULATED MICROSUSPENSION - Google Patents

Description

(19) DENMARK

Ip in) PUBLISHING WRITING αυ 11 + 51 83 B

DIRECTORATE OF THE PATENT AND TRADEMARKET SYSTEM

(21) Application No. 3025/74 (51) IntCI.3 C 08 F U / 06 (22) Filing date 6 Jun. 1974 C 08 F 2/18 (24) Race day 6 Jun. 197-4 (41) Aim. available Dec. 9; 1974 (44) Presented 27 · s ep. 1982 (86) International application no.

(86) International filing day (85) Continuation day - (62) Master application no. -

(30) Priority 8 Jun. 1973, 7320882, FR

(71) Applicant CELOE CHIMIE, 92800 Puteaux, ER.

(72) Inventor Nicolas Fischer, FR: Jacques Boissel, ER: Thomas Kemp, FR: Henri Eyer, FR.

(74) Associate Engineer Hofman-Bang & Boutard.

(54) Process for the preparation of polymers or copolymers of vinyl chloride in grafted microsus' pension.

The present invention relates to a process for preparing polymers or copolymers of vinyl chloride in grafted microsuspension.

By polymerization in microsuspension is understood a polymerization in the presence of organo-soluble initiators of

ISLAND

O at least one monomer dispersed by mechanical means in an aqueous medium containing an emulsifier or a large amount of protective colloid as a stabilizing agent to obtain a dispersion of particles if diameter is less than 5 µm 3 7 U5183 2

It is known that the classic initiators for polymerization of vinyl chloride at the normal polymerization temperatures give polymerization or copolymerization reactions a reaction kinetics with an auto-accelerated process which, firstly, cause difficulties in cooling and consequently poor utilization of the reactor. and secondly, incomplete utilization of these initiators, since a relatively significant amount of initiator must be used for the polymerization rate to be acceptable on an industrial scale.

To overcome these drawbacks, it has been proposed to use initiators with a faster decomposition, but it has been found that these initiators do not yield good results in polymerization in microsuspension.

It has also been proposed to accelerate the decomposition of the initiator in the presence of transition metal salts, especially in low temperature polymerization leading to very high molecular weight vinyl chloride polymers and / or a crystalline structure, however the reaction kinetics remain auto-accelerated.

Moreover, it is known by polymerization in microsuspension that the use of a grafting product containing the necessary initiator for the polymerization practically allows a suppression of the crust formation in the reactor and a partial moderation of the reaction's auto-acceleration, especially when the grafting rate of the product is high, but this improvement is limited nonetheless.

The object of the process according to the invention is to avoid the phenomenon of auto-acceleration and its disadvantages, so that the polymerization or copolymerization of vinyl chloride in microsuspension can be carried out at the usual temperatures with a higher reaction rate for a given apparatus and better utilization of the initiator and thus using smaller amounts of this with a very low crust formation and as a result optimal utilization of the reactor.

The process according to the invention, which is of the kind set out in the preamble of claim 1, is characterized by the characterizing part of claim 1. The soluble salts are used in such amounts that the molar ratio of metal salt: initiator is 0.1 - 10, preferably 0.1 - 2.

These salts can be introduced into the reaction medium before or during polymerization.

The useful complexing agents are compounds capable of bringing the metal from its water-soluble form to a form that is soluble in vinyl chloride and which has no inhibitory effect on the polymerization and on activation of the initiator by the metal. Compounds which fulfill these conditions are monocarboxylic acids which are heavily soluble in water, such as perfluorobutyric acid, o-bromochloroacetic acid, sulfosalicylic acid, naphthenic acid and octanecarboxylic acid, polycarboxylic acid such as succinic acid, tartaric acid, tartaric acid, tartaric acid, tartaric acid, tartaric acid, tartaric acid, tartaric acid, tartaric acid, tartaric acid, tartaric acid, tartaric acid, tartaric acid, tartaric acid and tartaric acid. , alkylphosphoric acids such as bis (2-ethyl) -hexylphosphoric acid, lactones such as ascorbic acid and their ester, and β-butyrol acetone, ketones with carbonyl group activating groups at the α or β position, such as acetylacetone, 1,3-dihydroxyacetone , benzoin, and carbazones such as diphenylthiocarbazone.

The amounts of complexing agent to be used are a function of the polymerization temperature, the cooling capacity of the reactor and the purity of the reactants. The amounts can reach the molar stoichiometric amounts relative to the metal salt.

4 145183

This complexing agent, in the presence of the metal salt, provides an organo-soluble complex which entrains the metal in the organic phase where it exerts an activating effect on the initiator. Thus, any activation of the initiator can be achieved by varying the amount and timing of the complexing agent in the reaction medium so that the kinetics of polymerization can be regulated at any time. The polymerization, which is initially slow in the absence of activator, is strongly activated in the process of the invention, and then less and less as the reaction proceeds. Thus, thanks to an optimal utilization of the cooling capacity of the reactor, the polymerization can be carried out in the minimum time.

This purpose is not achieved if the total amount of complexing agent is introduced from the beginning. In this case, the activation of the initiator is too rapid at the beginning of the polymerization, and therefore the initiator is decomposed too quickly and the reaction cannot proceed to the end of initiator deficiency.

Therefore, as mentioned, the initiator is activated by the progressive introduction of an organo-soluble metal complex which is pre-prepared by reaction of the above metal salts and complexing agents, or which is formed during the polymerization.

These complexes are used in amounts such that the molar ratio metal complex: initiator is 0.1 - 10. The activation of the initiator with the complex can be interrupted at any time by stopping the introduction of complexing agent or complex and / or by passing the metal ion from organo-insoluble form to water-soluble form by adding to the reaction medium a sequestering agent selected from the alkali metal salts of acids from the ethylenediaminetetraacetic acid group which, in addition to ethylene-diametetetraacetic acid, is represented by nitrilotriacetic acid, diethylenetriamine pentaacetic acid and N- (2-hydroxyethyl) The sequestering agent is used in amounts up to the molar stoichiometric amount relative to the metal salt.

The grafting product required for the polymerization is prepared according to the classical polymerization methods in microsuspension. For example, water, vinyl chloride with or without comonomer, an anionic emulsifier and an organo-soluble initiator are used. The monomer (s) is dispersed finely dispersed in the water by mechanical means such as e.g. a colloid mill, a quick gump, a vibration stirrer, or an ultrasonic device. The obtained micro-suspension is then heated under autogenous pressure and moderately stirred to a temperature determined as a function of the desired molecular weight of the product.

The grafting product is in the form of a dispersion of polymer or copolymer particles having a diameter of 0.05 - 2 µm.

For carrying out the process of the invention, the particles of the graft product must contain the total amount of initiator required for the polymerization. This amount is about 1 to 5% by weight relative to the polymeric graft product and is introduced prior to polymerization of the product.

The initiators soluble in the monomers are represented by organic peroxides such as diacyl peroxides, among which may be mentioned lauroyl peroxide, decanoyl peroxide and caproyl peroxide.

In the polymerization of the process according to the invention, the amount of grafting product used must be of an order of magnitude such that the polymer containing it constitutes 0.5 to 10% by weight relative to the sum of monomer or monomers to be polymerized and grafting polymer.

Thus, the amount of initiator present relative to the amount of monomer to be polymerized is very low compared to the known methods.

A greater amount of grafting product which gives polymer quantities in excess of 109e can also be used, but this is of little interest since the amount of polymer is then very significant in relation to the monomer (s) and thus the advantages obtained by the process are minimized. The grafting product present in the polymerization medium is sufficient to ensure dispersion of the monomer without the need for a new energy-consuming dispersion on the medium.

The monomers which can be copolymerized with vinyl chloride are those which are generally used in the classical copolymerization methods for vinyl chloride. Mention may be made of vinyl esters of mono- and poly-carboxylic acids such as vinyl acetate, propionate and benzoate, aliphatic, cycloaliphatic and aromatic esters as well as amides and nitriles of unsaturated mono- or polycarboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic acid fumaric acid, allyl, vinyl and vinylidene halides, alkyl vinyl ethers and olefins. The amount of comonomer can make up to 25% of the copolymer.

To improve the stability of the microsuspension, adding an anionic emulsifier in amounts of up to 2% by weight to the monomer (s) may be advantageous before and / or during polymerization. This emulsifier may be the same or the same as used in the preparation of the graft product. It is selected from the classic products such as fatty acid soaps, alkyl sulfates, alkyl sulfonates, alkylarylsulfonates, alkylsulfosuccinates and alkylphosphates.

This emulsifier may optionally be combined with a nonionic surfactant such as e.g. condensates of ethylene or propylene oxide with various organic hydroxyl group-containing compounds.

The amount of water used in the process of the invention should be such that the weight ratio of monomer + graft polymer: water (including graft water) is 0.3 - 1.5.

The polymerization temperature, which is a function of the quality of the polymer one wishes to obtain, is usually 30 - 70 ° C.

The process of the invention is particularly suitable for use in continuous polymerization as described in Danish Patent Specification No. 128,499. In this case, the introduction of the complexing agent or complex allows to maintain optimal reaction kinetics, ensuring a consistently high degree of conversion.

The vinyl chloride polymers and copolymers obtained by the process of the invention are separated from the polymerization medium in known manner, e.g. by filtration, coagulation and suction, scraping, decanting after centrifugation and atomization.

145183 7

The obtained polymers and copolymers are useful for the production of films, films, threads, hollow bodies, cellular materials, articles processed by calendering, extrusion, extrusion blowing, injection molding and molding, and to obtain coatings, cellular materials and articles which is designed by the known methods using plastisols, such as coating, rotational molding and dipping.

The invention is further illustrated by the following examples.

Example 1 Into a 25 m 2 reactor equipped with a stirrer is introduced 12,000 kg of water, 1200 kg of a grafting product prepared by microsuspension polymerization having a concentration of 400 kg of polyvinyl chloride containing 6 kg of lauroyl peroxide, and whose mean particle diameter is 0.4 µm, 60 kg sodium dodecylbenzene sulfonate, 0.5 kg copper sulfate and 10,000 kg vinyl chloride.

The mixture is heated to 52 ° C under autogenous pressure, and this temperature is maintained throughout the reaction time.

When the medium has reached 52 ° C, the addition of a 4 g / liter aqueous ascorbic acid solution is started. The amount of acid allowed is 65 g / hr for 5 hours, then 45 g / hr for 3 hours and finally 20 g / hr for the reaction to end.

After 9 hours, the pressure drop characteristic of reaction termination is observed. The supply of ascorbic acid and exhaust gas of unreacted monomer is stopped.

22,200 kg of a polymer dispersion is obtained, the concentration of which is 42.2% by weight, corresponding to a real degree of conversion of 89.7% by weight compared to the amount of vinyl chloride used.

The thin polymer film on the reactor walls is only 0.1% by weight relative to the amount of vinyl chloride used.

145183 8

The mean diameter of the particles obtained is 1.1 µm. After pulverization and crushing, the obtained polymer exhibits a viscosity index of 130 as determined by French standard T 51-013 ·

A plastisol prepared by mixing 100 parts by weight of the obtained polyvinyl chloride and 60 parts by weight of dioctyl phthalate has a viscosity determined on Brookfield viscometer type RTV (needle # 7-20 rpm) of 20 poise.

In comparison, various prior art experiments have been performed: A) Polymerization in non-seeded and non-activated microsuspension.

Into the same reactor as in Example 1 are introduced: 12,000 kg of water, 8 kg of lauroyl peroxide, 100 kg of sodium dodecylbenzenesulfonate and 10,000 kg of vinyl chlorido

The mixture is homogenized to obtain a microsuspension, the organic phase having a mean granulometry of 1 µm. The mixture is then heated to 52 ° C under autogenous pressure, and this temperature is maintained throughout the reaction time.

The reaction rate is irregular, very slow at the beginning, at which it accelerates and during the last two hours requires a maximum cooling of the reactor. After 18 hours, the reaction is over.

Unreacted monomer is degassed to obtain 20,300 kg of a dispersion with a concentration of 41% by weight, which corresponds to a degree of conversion of 83% by weight to the vinyl chloride used.

The crusts formed on the reactor walls constitute 1% by weight of the amount of vinyl chloride used.

The diagram below shows the evolution of polymerization rate in Example 1 (curve 1) and in experiment A (curve 2).

145183 9

Polymerisations * / Sk velocity ^ i y> / '; / * / «! Time

It is found that, although the amount of initiator used in the comparison experiment is higher, the reaction time is twice as long, the degree of conversion lower and the amount of crust formed ten times that of the process of the invention.

B) Polymerization 1 grafted, non-activated microsuspension.

Example 1 is repeated except that copper sulphate and ascorbic acid are not allowed.

After 15 hours of reaction, 22,000 kg of a dispersion having a concentration of 40.5% by weight, i.e. a degree of conversion of 85 µl by weight compared to the amount of vinyl chloride used.

Crusts corresponding to 0.6% by weight of the amount of vinyl chloride used are collected on the reactor walls.

The average diameter of the particles obtained is 1.08 µm.

By comparison with Example 1, it is found that the activation of the initiator by the process of the invention allows for the reaction of 9 hours instead of 15 hours, an increase of the conversion rate by 4% and a 6 times less crust formation.

C) Polymerization in non-seeded and non-activated microsuspension in the presence of fast decomposition initiators.

Into a 120 liter autoclave equipped with stirrer is charged: 60 kg of water, 0.1 kg of lauroyl peroxide, 0.120 kg of isopropyl percarbonate, 0.4 kg of sodium dodecylbenzenesulfonate and 40 kg of vinyl chloride.

The mixture is homogenized to obtain a microsuspension where the organic phase has an average granulometry of 1 µm.

The mixture is then heated to 52 ° C under autogenous pressure, and this temperature is maintained throughout the reaction time.

After 12 hours of reaction, a coarse dispersion containing large amounts of coagulate is obtained. Further, the formed crusts on the reactor walls make up 30% of the amount of monomer used.

EXAMPLE 2

Example 1 is repeated with a grafting product in which the particles have a mean diameter of 0.25 µm and polymerized at 42 ° C.

After 12 hours, 22,100 kg of polymer dispersion is obtained with a concentration of 42.4% by weight, corresponding to a real degree of conversion of 89.7% by weight with respect to the amount of vinyl chloride used.

The mean diameter of the particles obtained is 0.6 µm.

The polymer has a viscosity index of 180.

A plastisol made by mixing 100 parts by weight of the polyvinyl chloride obtained and 60 parts by weight of dioctyl phthalate has a viscosity of 75 poise.

EXAMPLE 3

Proceed as in Example 1, replacing the 10,000 kg vinyl chloride with 9-300 kg vinyl chloride and 700 kg vinyl acetate.

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After nine and a half hours of reaction, 22,400 kg of a copolymer dispersion containing 4.9% vinyl acetate, the concentration of which is 42.6% by weight, is obtained, corresponding to a real degree of conversion of 91.4% by weight with respect to the quantities used. monomers.

The mean diameter of the particles obtained is l, lyum.

The copolymer has a viscosity index of 130. A plastisol made by mixing 100 parts by weight of the copolymer obtained and 60 parts by weight of dioctyl phthalate has a viscosity of 30 poise and a gelation temperature of 144 ° C, determined by the method described by Heinrichs in Modern Plastics - April ig64 - page 165.

EXAMPLE 4 In the same reactor as in Example 1, 12,600 kg of water, 1,070 kg of a grafting product having a concentration of 39%, corresponding to 417.3 kg of polyvinyl chloride containing 6.3 kg of lauroyl peroxide and whose average particle diameter is 0.4 µm, are introduced. 84 kg of sodium dodecylbenzene sulfonate, 8,400 kg of vinyl chloride and 0.42 kg of copper sulfate.

The mixture is heated to 52 ° C and progressively introduced 840 g of dihydroxymaleic acid over 12 h at 105 g / h for 4 h, then 65 g / h for 4 h and finally 40 g / h for 4 h.

20,970 kg of a polymer dispersion is obtained with a concentration of 36.9%, corresponding to a degree of conversion of 87.1% by weight to the amount of monomer used. A thin film representing 0.12% by weight of the vinyl chloride used is collected on the reactor walls. The mean diameter of the particles obtained is l, lyum.

EXAMPLE 5

Example 4 is repeated, replacing dihydroxymaleic acid with succinic acid. After 14 hours of reaction, 21,070 kg of polymer dispersion is obtained with a concentration of 37%, corresponding to a conversion rate of 87.8%. The weight of the crust is only 0.15% by weight of the amount of vinyl chloride used.

The mean diameter of the particles is 1.08 µm.

EXAMPLE 6

Proceed as in Example 4, however, replacing copper sulfate and dihydroxymaleic acid with 840 g of vanadium acetylacetonate.

This is progressively introduced into the reaction medium at 52 ° C for 12 1/2 hours at 105 g / h for 4 h, then 65 g / kg for 4 h, and finally 40 g / kg for 4 1/2 h.

20,870 kg of a polymer dispersion is obtained, the concentration of which is 36.5%, corresponding to a conversion rate of 85 »5%. The crusts represent 0.18% by weight of the monomer used.

The mean diameter of the particles is 1, 09yu.m.

EXAMPLE 7

Several tests have been carried out with various activating agents under the following conditions: Insert into a 200 ml glass bottle after pumping the bottle out and then blowing it with gaseous vinyl chloride:

Deionized water 60 ml

A grafting product prepared by polymerization in microsuspension with. a concentration of 3%, 9%, corresponding to 3 g of polyvinyl chloride containing 0.04 g of lauroyl peroxide, and the mean part diameter of which is 0.4 µm 10.5 g

Sodium dodecylbenzenesulfonate 0.18 g

Vinyl Chloride 30 g

An activating agent consisting either of 10 x 10 3 -3 moles of metal salt and 5 x 10 5 moles of complexing agent or of 10 x 10 3 moles of preformed metal complex.

The bottle is hermetically sealed, placed in a thermostated bath at 52 ° C and shaken. This continues for 5 hours, after which the bottle is cooled, degassed, the water evaporated to obtain the polymer formed.

The various activating agents as well as the results obtained are listed in the table below.

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TABLE

Experiment Metal Salt Coraplexing Agent Polymer Weight Percent.

relative to vinyl chloride

A (together n R

similar) 0 0 ° 8 B copper sulfate sulfosalicylic acid 16 C "naphthic acid 3 D" octanoic acid 3 E "succinic acid 4.4 F" tartaric acid 16 G "maleic anhydride 4.1 H" bis- (2-ethyl) -hexyl-10, 2 phosphoric acid I "ascorbic acid 23 J" -butyrolactone 14 K "benzoin 2.8 L" diphenylthiocarbazone 3 M iron sulfate ascorbic acid 23 N nickel sulphate "20 0 zinc sulphate" 25 P vanadium sulphate "59 Q manganese sulphate" 12 R chromium sulphate n 23 S tin chloride? 33 T Cobalt Nitrate "10 U Silver Nitrate" 8.6 V Titanium Acetyl Acetonate 1.3 W Chromium Acetyl Acetonate 6.6 X Nickel Acetyl Acetonate 6.9

The table clearly shows the effect of the activating agents on the initiation of the polymerization.