DE1006159B - Process for the suspension polymerization of vinyl monomers - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN / jfämm < PATENT OFFICE

kl. 39 c 25/01

INTERNAT. KL. C 08 f

EDITORIAL 1006159

M 28731 IVb / 39 c REGISTRATION DATE: NOVEMBER 9, 1955

NOTICE
THE REGISTRATION
AND ISSUE OF THE
EDITORIAL: APRIL 11, 1957

The vinyl monomers, especially the vinyl chloride, are preferably used in emulsion or suspension polymerized.

In emulsion polymerization, the monomer is emulsified with stirring by means of a capillary-active substance in an aqueous medium and in the presence of a suitable catalyst; The polymer is deposited from the latex obtained either by coagulation with salts or by drying.
The product obtained by this process always retains more or less large amounts of emulsifier and the catalyst residues and, if high purity is required, cannot be used.

When polymerizing in suspension, however, the monomer is by stirring in one for monomer and Polymeric nonsolvent, generally water, dispersed in the presence of an appropriate catalyst; this dispersion is made by means of so-called dispersants - which are distributed around the monomer droplets and prevent agglomeration - stabilized. The polymerization in suspension, i.e. H. in attendance of dispersants, has the advantage that the polymer obtained is obtained in grains and then through Filtration can be deposited from the aqueous suspension, furthermore have those in suspension Polymers have a high degree of purity, which allows them to be used in products intended for special Applications are intended. The factors that govern suspension polymerization are agitation of the medium and the effect of the dispersants.

As a dispersant, starch, gelatin, cellulose derivatives, polyvinyl alcohol, water-soluble ones are generally used Urea-formaldehyde condensates, polymers and copolymers of acrylic acid or maleic anhydride etc. used.

These substances have on the granulation of the polymer and on the formation of the incrustations in the Inside the reaction vessel a special influence.

The regulation of the granulation appears particularly difficult. On the other hand, have the structure of the polymer grains and their size are of considerable importance, as they affect the processability of the product. During the polymerization, the polymer grains tend to form agglomerates excessively Size and to adhere to the walls of the reaction vessel, making hard-to-remove incrustations that limit the heat exchange with the outside.

It has now been found that it is very advantageous as a dispersant in suspension polymerization special copolymers are used, which in the usual way by grafting on polymeric chains on a different type of polymer, so-called graft polymer, are obtained.

procedure

for suspension polymerization
of vinyl monomers

Applicant:

MONTECATINI, Soc. Gen. per l'Industria Mineraria e Qiimica, Milan (Italy)

Representative: Dipl.-Ing. Dipl.-Chem. Dr. phil. Dr. techn. J. Reitstötter, patent attorney, Munich 15, Haydnstr. 5

Claimed priority:
Italy from November 18, 1954

Domenico Maragliano and Enrico Cernia,

Milan (Italy),
have been named as inventors

For example, polystyrene solution has the ability to add the oxygen in the air (in the same way as it does occurs with cumene) and to form peroxide groups:

O
O
- CH, -CH-CH ₂ -C-CHo-CH-

A monomer other than styrene is then added to the solution, such as vinyl acetate with a redox activator, z. B. ferrogluconate. The ferrous ions Fe ++ react with the hydroperoxide groups; by Generate free radicals along the polystyrene chain:

ROOH + Fe ++ RO + OH- + Fe +++
you will stick to the polystyrene side polyvinyl acetate

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3 4

Can bind chains, which by saponification in particular show up as dispersants

Polyvinyl alcohol side chains transform: very active the copolymers produced by polymerization

of vinyl polymers such as styrene, acrylonitrile, vinyl

X chloride, vinylidene chloride, etc., in aqueous, polyvinyl

I 5 containing alcohol, polyacrylamide, polyacrylic acid, etc.

(CH CHOH) solution were recovered; the obtained graft

ι Polymers consists of a main chain on polyvinyl

'_____ alkyl or polyacrylamide-polyacrylic acid base etc. and

from lateral branches of styrene, acrylonitrile, etc. It ίο z. As polyacrylamide prepared by a 10 ° / ₀ acrylamide solution is heated in water with 1 ° / ₀ persulfate and bisulfite 0.1% at 100 ° 1 hour. The solution to the

The same amount of styrene is used for the polymers obtained

I to like initially the acrylamide, together with 5%

_ Q 15 persulfate and 0.25 ° / ₀ styrene, calculated on bisulfite, and

ι heated to 90 ° for 3 hours. During this time

/ N ^ one notices one as the polymerization proceeds

Formation of latex, its viscosity continuously

(X = an end group)

increases. It is therefore necessary to use the polymer mixture

20 gradually dilute with warm water so that the Final latex a dry product content of no more

Such a copolymer is markedly different from containing 7%. The dry latex is an acrylic normal copolymer. While the usual amide content of 42 ° / ₀ , based on dry matter, on copolymers through copolymerization of two or and the dry product is 80% water-soluble. The multiple monomers are obtained and a 25 styrene can have the same way in the presence of poly structure in which the units of the component vinyl alcohol and polyacrylic acid are polymerized, nents are distributed in an irregular manner, the latter can be obtained either by polymerizing the distribution of the components in the grafted mixed acrylic acid or by hydrolysis of polyacrylonitriles predetermined polymeric, as is obtained by the following in the heat, for example, with 25 ° / ₀ NaOH; In the scheme, in which A and B are two different monomeric monomers, in this case the polyacrylic acid is shown after the solidification has taken place: soap precipitated by neutralizing with sulfuric acid

γ. . »* Becomes α; the polymer mass is slightly ammoniacal

lischen water again and can by dialysis

H = B-B-B-B-B are cleaned. A grafted polyacrylic acid

jjj — A agaa BABBABAA ³ ^ styrene copolymers containing latex, which is good suspen-

_ _r . . . 7th . . . . . had the following properties

IV = AAAAAAAAAAAAA _properties .

B — B — B — B B — B — B — B Dry content 98%

, ".. ,, ._, _,,, -r. · Α absolute viscosity at 25 ° 86 cP

I and II are the simple polymers on Baas A 40 surface tension at 10 and 5% .. 72 dynes / cm and B, III is a normal copolymer with the mono-polyacrylic acid content, on the dry

mere units that are related to substance with a certain order 38 ° /

the laws of copolymerization are distributed. In the water solubility of the 'dry' . '.'. '.'. '. 65%

generally cherish the properties of this copolymer

in many respects between those of the simple 45 in the manufacture of the above-mentioned grafted Polymers I and II and the graft polymer IV, the polymer can have the ratio of polymer to a "backbone" of A monomers and lateral branches of monomers within very wide limits, e.g. B. from of B monomers; if the extension of the rows is 1: 8 to 9: 1, but preferably from 2: 8 to 7: 3, follow A and the order B is large enough, so takes can be varied. The graft polymers, which are known as suspendas relevant copolymer in a certain range 50 solvent in the dispersion polymerization of vinyl die Properties of the polymer I or those of the poly-monomers, especially of vinyl chloride, are used meren II an, d. H. in this case one has to be less with, allow a polymer in uniform an average as with a succession of grains and with excellent mechanical properties of their own to do. One of the easiest ways to get results.

to obtain type IV polymers is as follows: 55 This group of dispersants is already in A very small amount of poly is effectively dissolved in a suitable solvent; they facilitate the regumeres, which, to a certain extent, contain mobile atoms, the size of the polymer grains and the polys are, adds a new monomer, heats with a merizate structure and largely prevents crusts high temperature in the presence or formation in the reaction vessel. Absence of catalysts. Under these conditions- 60. .

through chain transfer reaction. Example

The polymer molecules present in solution are placed in an autoclave equipped with a stirrer

Convert macro radicals to which the side chains 400 kg of water, 100 kg of vinyl chloride, 0.015 kg of a of the new monomers are grafted on. grafted copolymers (vinyl chloride-polyvinyl alcohol

The grafted copolymers, which are implemented in the poly 65 70:30) and 0.5 kg of benzoyl peroxide. It will merization of the vinyl monomers as a dispersant for 5 to 6 hours at 50 °.

have proven to be active are those that are in the main chain. A product known as polymer I is obtained

or to become hydroxyl in the grafted side chains; It has a snow-white appearance and fine groups such as —OH, —COOH, —CONH ₂ etc., grain size. A second attempt at polymerization was included. 70 carried out under the same conditions; as a suspen-

However, only polyvinyl alcohol was used instead of the graft polymer mentioned; man So obtained a polymer II of coarse, heterogeneous grain size. The percentage of crust formed in both cases was the following:

Polymer I
0.20%

Polymer II
7%

Clear width
in mm On every sieve Polymer
II Meshes / cm ² retarded
Polymer percentage _ 1.6 Polymer
I. 2, - 16 1.2 _ 3, - 25th 1.02 - 11.5 36 0.75 - 15 - 64 0.60 - 19th 100 0.54 - 7th 121 0.49 - 15th 144 0.43 - 9.5 196 0.385 .—. 7th 256 0.300 3 400 0.250 - 5, - 576 0.200 0.5 2, - 900 0.150 12, - 1,- 1600 0.120 14.5 - 2,500 0.102 67.00 3 600 0.088 5.5 - 4,900 0.075 0.5 - 6 400 0.060 -. 10,000 - ·

Example 2

In an autoclave provided with a stirrer, 400 kg of water, 100 kg of vinyl chloride, 0.010 kg of one Graft copolymers (styrene-polyvinyl alcohol 80:20) and 0.5 kg of benzoyl peroxide stirred at 50 ° for 5 to 6 hours.

A polymer I is obtained in high yield (85 to 90%) and uniformly with a fine grain size. A second Polymerization experiment was carried out in the same proportions, but using as a suspending agent in place the grafted copolymer of simple polyvinyl alcohol was used; a polymer II is obtained in this way.

The crust percentage was as follows:

35

40

45

Polymer I
0.11%

Polymer II
9.5 o / _o

When the crusts were removed, the two polymers were subjected to granulation analysis by the DIN network scale 1171 was used, resulting in the following:

Light inner On every sieve Polymer Expanse retarded II Meshes / cm ² in mm Polymer percentage Polymer 6th 1.6 I. 4.5 16 1.2 _ 18, - 25th 1.02 - 21 36 0.75 . 19.5 64 0.60 -. 13th
IU, 100 0.54 121 0.49 .—. 144 -

55

6o

After the crusts had been removed, the two polymers were subjected to granulation analysis Application of the DIN 1171 network scale with the following result:

Light inner On every sieve Polymer Expanse retarded II Meshes / cm ² in mm Polymer percentage 7, - Polymer 4 - 0.43 I. 2.5 196 0.385 _ 3.5 256 0.300 - 1 - 400 0.250 -. 576 0.200 8th- 900 0.150 3.5 - 1600 0.120 28, - - 2,500 0.102 52.5 . 3 600 0.088 4.5 - 4,900 0.075 3.5 6 400 0.060 10,000 -

Example 3

In an autoclave provided with a stirrer, 400 kg of water, 100 kg of styrene, 0.015 kg of one are grafted Styrene-polyacrylic acid copolymers (50-50) and 0.4 kg of benzoyl peroxide for 4 hours at 80 °. You get again a product called "polymer I". Polymerization occurred under the same conditions made, in which, however, polyacrylic acid instead of the grafted copolymer as a suspending agent was used. A polymer II was obtained in the process. Finally there was a third polymerization made in polyvinyl alcohol as a suspending agent in place of the grafted copolymer by under the otherwise the same conditions of the specified polymerization were carried out; a polymer III was obtained. The amounts of incrustations that formed in the three cases were as follows:

Polymer I Polymer II Polymer III
0.25% 2% 6%

As soon as the confusion was removed, the three polymers were subjected to granulation analysis, using the DIN 1171 network scale with following results:

T ir-Trf-A On every Sieve retarded Polymer Polymer Meshes Expanse Polymer percentage II III cm ² mm Polymer I. 6th 16 1.6 -. 23 25th 1.2 -. - 45 36 1.02 - 12th 64 0.75 - - 8th 100 0.60 - 3 121 0.54 - 2 144 0.49 - - 1 196 0.43 - 1 -. 256 0.385 - 2 400 0.300 30th - 576 0.250 50 -. 900 0.200 - 14th - 1600 0.150 4th 2 -. 2,500 0.120 20th 1 -. 3 600 0.102 65 - -. 4,900 0.088 6th - - 6 400 0.075 - 10,000 0.060 -

65

Example 4

400 kg of water, 100 kg of vinyl acetate with 0.6% 2, 2-azo-

bisisobutyronitrile and 0.02 kg of grafted polyacrylamide-styrene copolymer 50-50 filled; it is for 4 hours at 65 ° and then for a further 3 hours at 80 ° Then the slurry is heated and cooled with stirring. A snow-white powder is obtained, which can be seen on the microscope has round grains of high homogeneity and crystalline transparency; this product is called Polymer I referred to.

In a similar polymerization, grafting is used as a suspending agent in place of the above Copolymers here a polyacrylic acid-styrene graft polymer used in the same amount. One achieves such a polymer similar to the preceding one, which is referred to as polymer II.

In a third attempt exactly the same amount of polyvinyl alcohol is used as the suspending agent; a significantly coarser and less uniform product is obtained, which is referred to as polymer III will.

The amounts of incrustation that formed in the three cases were as follows:

Polymer I Polymer II Polymer III 0.3 7o 0.40 / ₀ 5o / _o

After separation of the crusts, the three polynes were subjected to the granulation analysis, which are shown below The DIN 1171 network scale was applied with the following result:

Meshes
cm ³

Inner
Expanse
in mm

Percentage of polymer residue left on each sieve

Polymer

Polymer II

Polymer III

16 1.6 25th 1.2 36 1.02 64 0.75 100 0.60 121 0.54 144 0.49 196 0.43 256 0.385 400 0.30 576 0.25 900 0.20 1600 0.15 2,500 0.12 3 600 0.102 4,900 0.088 6 400 0.075 10,000 0.060

- 4, - 2.5 - 5, - - 23, - - 32.00 - 19.00 7 - - 5, - - 2.5 2.0 35.5 - 47.00 - 12, - - 3.5 -

30th

35

40

45

3, -14, -
58, -23, -

2, -

Example 5

400 kg of water, 100 kg of styrene, 0.015 kg of a grafted copolymer (styrene-polyvinyl alcohol 75:25) and 0.4 kg of benzoyl peroxide. It is stirred for 4 hours at 80 °. You get a polymer with a uniform appearance and notices no incrustations in the interior of the reaction vessel.

Example 6

In an autoclave equipped with a stirrer, kg of water, 20 kg of vinyl acetate, 0.02 kg of one are placed grafted copolymers (styrene-polyvinyl alcohol 20:80) and 0.5 kg of 2,2'-azobisisobutyronitrile introduced; it will heated to 75 ° and while maintaining this temperature, the autoclave with 80 kg of vinyl chloride within Hours loaded; the polymerization is continued for an hour and finally the recovered Bottled polymers. It is obtained in fine and regular grains and has a viscosimetrically determined molecular weight from 10,000 and can be used in the manufacture of varnishes.

Claims (9)

Claims 1. A process for the suspension polymerization of vinyl monomers, characterized in that the Polymerization in the presence of a dispersant composed of a grafted copolymer consists, which is formed by copolymerization of an olefinic compound in the presence of a Polymers is obtained. 2. The method according to the preceding claim, characterized in that the dispersant is a copolymer obtained by polymerizing an olefinic compound in the presence of Vinyl acetate with subsequent saponification or in the presence of a water-soluble macromolecular Connection is achieved. 3. The method according to the preceding claims, characterized in that the dispersant is a copolymer obtained by polymerizing an olefinic compound in the presence of a copolymer, which contains vinyl acetate as a component, or in the presence of polyvinyl alcohol is won. 4. The method according to the preceding claims, characterized in that the grafted copolymer by polymerizing an olefinic compound in the presence of polyacrylamides is won. 5. The method according to the preceding claims, characterized in that the grafted copolymer obtained by polymerizing an olefinic compound in the presence of polyacrylic acid will. 6. The method according to the preceding claims, characterized in that the grafted Copolymers by polymerizing an olefinic vinyl series compound in the presence of a preformed one Polymers is obtained. 7. The method according to the preceding claims, characterized in that the grafted Copolymers by polymerizing vinyl chloride or vinylidene chloride or styrene or Acrylonitrile and its derivatives is obtained in the presence of a preformed polymer. 8. The method according to the preceding claims, characterized in that the polymerized in dispersion Monomers which is styrene alone or in the presence of other copolymerizable monomers. 9. The method according to the preceding claims, characterized in that the polymerized in dispersion Monomers the vinyl chloride alone or in the presence of other copolymerizable monomers is. © 609 868/444 4.57