DE2628665A1 - PROCESS FOR THE PREPARATION OF POLYMERS FROM VINYL AND VINYLIDEN HALOGENIDES AND COPOLYMERS - Google Patents

Description

It is known that vinyl resins are plasticized or from the hard, horn-like and rigid states to one soft, plastic workable state can be converted by placing them at elevated temperatures adding certain plasticizers such as dioctyl phthalate. These vinyl polymers or resins are called dispersion resins or paste resins and are commonly used made using the emulsion polymerization technique, although also a suspension polymerization process can be used.

When the vinyl resin is mixed with a plasticizer, " it is referred to as a "latex". Due to the fluidity of the latex, it can be converted into various valuable products are processed. The latices can be used to make molded products, coatings, and the like. Accordingly the dispersion resin must be able to be easily and evenly mixed with a plasticizer, to form low viscosity latices that are stable and have good transparency and clarity and contain particles of uniform and suitable size.

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With the usual emulsion polymerization processes it was difficult to obtain suitable latices, since the latices usually contain particles of different sizes, that were either too small or too big. Various proposals have been made to overcome these difficulties to eliminate, however, none ultimately had the desired success. For example, using a A number of different emulsifiers and catalysts have been proposed. In addition, the change in the polymerization conditions suggested. However, in almost all of these cases, too much coagulation resulted, thereby the latex obtained contained too much coagulum or partially agglomerated particles which, by precipitation, reduced the yield to decrease. In addition, the durability of these latices left a lot to be desired. It is therefore desirable To obtain latices which change very little in terms of their viscosity during storage and a have and maintain good heat resistance.

Another very harmful and difficult to resolve problem in the large-scale production of polymers and copolymers of vinyl halides and vinylidene halides, when they _{are polymerized alone or with other vinylidene monomers with terminal CH 9} = C ^ groups, is ι the formation of undesirable polymer approach to the inner ^ surfaces of the reactors. This deposit or this polymer build-up on the inner surfaces of the reactors not only affects the heat transfer, but also reduces productivity and negatively affects the polymer quality, such as the production of finer particles than desired with the resulting negative effect on viscosity. It is clear that this polymer batch or the polymer deposits must be removed. If this is not the case, more and more polymer deposits form on top of what is already there, which leads to a hard, insoluble crust.

609883/1 1 38

Up until now it was common for a worker to climb into the reactor and remove the polymer build-up from the walls, the baffles and scraped off the stirrers. This way of working is not only costly in terms of both labor and cost also with regard to the shutdown of the reactor, but results in possible damage to health. Different methods have heretofore been proposed to remove the polymer base, such as solvent cleaning, various hydraulic and mechanical reactor cleaners and the like. However, none of these proposals ultimately worked proved to be suitable to remove the polymer batch. It is therefore very desirable to have a polymerization process to have at hand, in which no polymer build-up or no polymer deposits occur. Unfortunately, none of that is known emulsion polymerization processes are capable of solving this problem and the other problems mentioned above to solve. There is therefore a need for a polymerization process which does not have all of these disadvantages.

It has surprisingly been found by the applicant that if a suitable combination of polymerization conditions and ingredients is used, latices can be produced which all have the necessary and desired properties and no or only very little polymer build-up occurs. The inventive method comprises carrying out the polymerization reaction of vinyl monomer or vinyl monomers in aqueous alkaline medium using an oil-soluble polymerization initiator at a temperature below about 48 ° C in the presence of an ammonium salt of a high fatty acid containing 8-2o carbon atoms, and at least a long chain alcohol that has 14-24 carbon atoms contains, the ratio of alcohol to emulsifier

is equal to or greater than 1, p and wherein the reaction before the polymerization

participants / are completely mixed. The so produced Dispersion resins or paste resins have improved

6098.8 3/1136

Flow properties and heat stability and are suitable for producing sheets or films from them which have excellent properties Have clarity and improved water resistance. If the above procedure is used, will the polymer batch in the reactor is substantially reduced and a large number of polymerizations can be carried out carried out in the reactor without opening it, reducing the amount of vinyl chloride released into the surrounding Atmosphere, is significantly reduced.

In the present invention, the term "vinyl dispersion resins" means polymers and copolymers of vinyl halides and vinyl oxide halides such as vinyl chloride and vinylidene chloride. The vinyl halides and vinylidene halides can be copolymerized with one another or each of them can be copolymerized with one or more vinylidene monomers having at least one terminal CH ₂ = C 1 group. Examples of such vinylidene monomers are, ß-olefinically unsaturated carboxylic acids, for example acrylic acid, methacrylic acid, ethacrylic acid, λ -chloroacrylic acid, α-cyanoacrylic acid, esters of acrylic acid! such as methyl acrylate, ethyl acrylate, butyl acrylate, octyl acrylate, cyanoethyl acrylate, esters of methacrylic acid, e.g. methyl methacrylate and butyl methacrylate, nitriles such as acrylonitrile and methacrylonitrile, acrylamides such as methyl acrylamide, N-methylol acrylamide and N-butoxymethacrylamide, vinyl ether, and vinyl ether and vinyl ethyl Styrene and styrene derivatives including. ^ -Methylstyrene, vinyl toluene and chlorostyrene, vinyl naphthylin, allyl and vinyl chloroacetate, vinyl acetate, vinyl pyridine, methyl vinyl ketone and other vinylidene monomers of this type, which are known to the person skilled in the art. The present invention is particularly applicable to the preparation of vinyl dispersion resins or paste resins obtained by polymerizing vinyl chloride or vinylidene chloride alone or in admixture with one or more vinylidene monomers copolymerizable therewith in amounts up to about

609883/1136

8o wt .-%, based on the weight of the monomer mixture, have been prepared. The particularly preferred vinyl dispersion resin is polyvinyl chloride. Therefore, the invention is to simplify and facilitate, by way of polyvinyl chloride described, this description only erläute ^{rn <^} and is not limiting.

The present process for the preparation of vinyl dispersion resins is carried out using the measures of emulsion polymerisation technology in an aqueous medium. However, it is necessary according to the present invention that certain specified materials are present in the polymerization medium and certain conditions of the polymerization must be adhered to in order to obtain the desired result.

With the polymer approach, it is necessary to use a fatty acid derivative as an emulsifier. To get the correct and improved To obtain water resistance and heat resistance of films made from plastisols or latices of vinyl dispersion resins the ammonium salt of a long-chain saturated fatty acid is used. It it has been found that the use of alkali metal salts of fatty acids discolored or yellowed films or sheets these plastisols results. Furthermore, the water resistance of the films is lost, even if only traces' of alkali metal are present. This means that alkali metal ions must be completely absent. The saturated ones Fatty acids used in accordance with the invention can be either natural or synthetic in origin and should contain 8 - 20 carbon atoms. as Examples of such acids can be lauric acid, myristic acid, palmitic acid, marganic acid, stearic acid and the like, beef tallow, Coconut oil and the like can be mentioned. The ammonium salt emulsifier is used in an amount ranging from about 0.5 to about 4.0% by weight, based on the weight of the monomer or monomers to be polymerized, is used. It is also

609883/1 136

possible mixtures of ammonium salts of fatty acids in the To use emulsifier system.

The ammonium salt can be obtained by mixing the fatty acid with j Ammonium hydroxide, separation of the salt and addition to the polymerization medium can be prepared in the usual way. However, it is preferred to form the ammonium salt in situ, i.e. that the fatty acid and ammonium hydroxide are separate added to the polymerization mixture or the polymerization medium, in which they are used to form the salt react. An excess of ammonium hydroxide over the equimolar amount of the fatty acid should be used. This excess helps to keep the reaction medium in the alkaline range, which is important, as further below

is set out.

In addition to the ammonium salt of a long chain fatty acid eemulsifier is used in combination with a long-chain saturated alcohol with 14-24 carbon atoms. Examples of such alcohols are tetradecanol, pentadecanol, hexadecanol, heptadecanol, octadecanol, Nonadecanol, eicosanol, heneicosanol, docosanol, tricosanol and tetracosanol. Mixtures of the alcohols can be used such as a C. ^ alcohol and a C.g alcohol Alcohols with fewer carbon atoms can also be used when combined with long-chain alcohols are mixed. Examples are a mixture of dodeca- | called nol and octadecanol.

While a ratio of alcohol to the ammonium salt of the fatty acid of 1.0 can be used, the best will be Results obtained when the ratio is greater than 1.0.

In practicing the invention, the polymerization reaction is carried out at a high pH. The method can be carried out at a pH in the range of

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2628685

about 7, o to about 12, ο can be carried out. However, it is preferred to operate in a pH range of from about 8.0 to about 10.5. If the pH is too high, too much NH ₄ OH is required and if the pH is too low, for example below 7. o, the polymer deposition or the polymer build-up in the reactor increases, as does the coagulate. The amount of NH4OH used to properly adjust the pH depends in part on the particular emulsifier system used in the reaction mixture.

The process described here is carried out in the presence of a compound which is capable of the Initiate polymerization reaction. Free radical initiators normally used for polymerization of olefinically unsaturated monomers are satisfactory for use in the present process, provided that they do not contain alkali metals such as sodium and potassium. The appropriate ones Initiators or catalysts include, for example, the various peroxy compounds such as persulfates, benzoyl

Butyl
peroxide, t- <hydroperoxide, t-butyl peroxypivalate, cumene hydroperoxide, t-butyl diperphthalate, pelargonyl peroxide and 1-hydroxyeyelohexyl hydroperoxide, azo compounds such as azodiisobutyronitrile and dimethylazodiisobutyrate. Further suitable initiators are water-soluble peroxy compounds such as hydrogen peroxide, lauryl peroxide and isopropyl peroxide dicarbonate. The amount of initiator is generally in the range between 0.1 to about 3% by weight, based on the weight of 100 parts of monomer or monomers to be polymerized, and preferably between about 0.15 and about 1.0% by weight.

In the present process, all of the initiator is added at the beginning of the polymerization. The initiator is added initially by adding it to the monomer premix with the other ingredients of the reaction mixture. This is especially the case when the

609883/1136

Premix is homogenized before introduction into the reactor. However, if the initiator to the

r monomeric premix is added and then homogenized, it is necessary that the temperature during the \ Vormischungsstufe and the homogenization is ^below! the minimum reactivity temperature of the particular initiator (s) used is maintained. For example, if a premix of vinyl chloride, water, ammonium salts of a fatty acid and the alcohol is prepared and then t-butyl peroxypivalate is added, the temperature is maintained at 25 ° C during the mixing step and then during the homogenization step. After the homogenized mixture has been introduced into the polymerization reactor, the temperature is then increased to the temperature at which the reaction is to take place.

The reaction temperature of the polymerization process of the present invention is important because the intrinsic viscosity (IV) is a direct function of the reaction temperature is. This means that the higher the temperature, the lower the intrinsic viscosity. Hence the intended one End use of the resin to be produced will normally dictate the reaction temperature. For example, if Dispersion resins are produced that are used as coatings or for casting flexible films a higher temperature is used to ensure a free flowable plastisol if that Resin with a plasticizer and other normally used additives such as paints, pigments and fillers is mixed. It has been found that for the end use for which the dispersion resins are particularly suitable Polymerization temperatures in the range of about 30 ° C to about 70 ° C are satisfactory. It will however, it is preferred to use temperatures in the range of about 40 ° to about 55 ° C. It should also be noted be that as the reaction temperature rises, the polymer batch rises. However, this polymer approach is not

609883/1136

-9- i

of the type with a resinous crust and can easily be removed by rinsing or hosing down with water and j without opening the reactor, if suitable spray nozzles are installed in the reactor. On the other hand, even this polymer approach or this polymer deposition can lead to a; can be controlled to some extent by keeping the walls i of the reactor cool during the polymerization reaction. ■ This can be achieved by conventional means such as a jacketed reactor, said cooling water circulating in the jacket. When using this technique, it is possible to polymerize at higher temperatures in order to obtain the desired dispersion resins with a low intrinsic viscosity and at the same time to reduce the polymer deposition. For example, if the polymer! sation reaction medium is maintained at a temperature of about j 42 ° C, water at a temperature of about j 15 ° C is circulated through the jacket. ;

Plastisols are made from the dispersion resins according to The present invention prepared by using conventional measures and devices 1oo parts by weight of the Disper- J sion resin in powder form with about 30 to about 100 parts by weight of one or more plasticizers evenly mixed or mix intimately. The suitable plasticizers can be alkyl and alkoxyalkyl esters of dicarboxylic acids or esters of polyhydric alcohols and monobasic acids can be described. Examples of such plasticizers are dibutyl phthalate, dioctyl phthalate, dibutyl sebacate, dinonyl phthalate, di (2-ethylhexyl) phthalate, di (2-ethylhexyl) adipate, dilauryl phthalate, dimethyl tetrachlorophthalate, butyl phthalyl butyl glycolate and glyceryl stearate. The preferred Plasticizers are liquid diesters of aliphatic

i see alcohols with 4 - 20 carbon atoms and dibasic i

I see carboxylic acids with 6-14 carbon atoms.

The plastisols made from the dispersion resins of the present invention should have the desired flow

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-1ο-

(yield) and preferably have little or no dilatance. The "yield" is simply called resistance to | the flow and is normally determined numerically by j viscosity measurements using known standard techniques. Usually you get this
Values by calculating from viscosity measurements under

Turn a Brookfield Model RVF Viscometer to ASTM Method D1824-61T. The flow is from the viscose! ity measurements of the plastisols at various rpm
initial production and after aging intervals
certainly. The viscosity is in centipoise (cps) at
a temperature of 23 ⁰ C measured. In the following

In specific examples, the viscosity measurements were made at 2 rpm and 2o rpm and recorded as V ₂ and V " presses.

The following examples illustrate the invention. In the
Examples all parts and percentages refer to the |

Weight unless otherwise stated. i

Example j

In this example, a series of experiments are carried out ^! led to show the effect of using saturated alcohols' of different chain lengths. In any case | the following approach was used with the exception that the alcohol was varied in each experiment. All numbers i are in parts by weight, based on the weight of the entire j composition: j

Vinyl chloride 100, o _;

Water (demineralized) 125, ο j

Laur ins äure 2, ο

NH ₄ OH ο, 244

t-butyl peroxypivalate ο, o5

Alcohols different.

In each of the experiments, a monomer premix tank or
- Vessel cleaned of air by nitrogen. Then became

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-11-

the premix tank is charged with water and then vinyl chloride with stirring. The temperature in the premix tank was maintained at about 25 ° C with the aid of a cooling jacket. The lauric acid and the ΝΗ, ΟΗ were added, after which the alcohol and finally the t-butyl peroxypivalate were added. The mixture was stirred for 15 minutes under a nitrogen atmosphere. The mixture (monomer premix) was then passed through a two-stage Manton Gaulin homogenizer at a temperature of 25 ° C. and then into the polymerization reactor which contained a nitrogen atmosphere. The pressure in the first stage of the homogenizer was 600 psig and the second stage was 700 psig. Thereafter, the contents of the reactor were heated to the polymerization temperature, ie 45 ° C., and held there during the reaction until the desired reaction had been achieved, which is indicated by a pressure drop to 50 psig. The reactor was then cooled, blown off and emptied. The amount of coagulum, scraped polymer batch and reactor conditions were recorded. The corresponding data are in the; Table I named.

In order to determine RVF viscosity plastisols .wurden with the polyvinyl chloride resin (PVC) of each run using the following approach produced: PVC 1oo parts

Dioctyl phthalate 4o "

Dioctyl adipate 3o "

epoxidized soybean oil 5 "Ca-Zn-Phosphite 3"

The viscosity data are also given in Table I.

609883/1136

σ> ο co CD OO CO

1 2 Table I. 2.1 - Attempt no. - 2.1 Alcohol ö c's _ - - Alcohol 8 c's - _ Alcohol 10 c's - - 2.1 Alcohol 12 c's _ - Alcohol 14 c's - _ - Alcohol 16 c's - - Alcohol 18 Cs - - - Alcohol 20+ Cs - - - Alcohol 22+ c's _ Alcohol I2c's + l8c's _ - - Alcohol 14c's + 18c's 56 45 - Alcohol l6c's + l8c's - % Sales 86 Reactor approach

Walls stirrer shaft baffle plate bottom coagulum,% scraped off,% Sedimentation,% 1 hour

4 hours

1 day 4 days slurry pH surface tension Total Solids,% 2.1

81

C. 1-2 " 1/2 " 1-1-1 / 2 " O 1-2 " 1 / 2-1 " 1-1-1 / 2 " A. 1/2 " 1 / 2-1 " 1-1-1 / 2 " G 1-2 " 1/2 " 1-1-1 / 2 " U too thick too thick too thick L.
Λ too thick too thick 7.0 Λ
T 7th O to E. 8th O thick D. 9 O 9 O ' 9.0 • 9.4 9.4 28.2 26.8 26.7 19.6 39-5 37.0

2.1

90

2.1

86

■ to
I. ' I. 2: 1 / 8-1 / 4 " easy film 1/16 "stained hO 1/8 " 1 / Ϊ6-1 / 8 " 1/16 * 00 1/4 " 0.08 CD 1/8 " 0.08 CD 0.6 0 cn 0.6 0 0 0 0 O 0 8.7 0 35.6 9 «5 38.4 28.8 4l.o

Table I, continued

Plastisol mixture

Brookfield RVF viscosity, cps

O CJD OO OO CO

initially 1 day 1 week

V V V

2o

2o

To thick, could. not dry

24,000

14,500 120,000

4l, 600 212,000

72,000

could
not
dry

8,500 22,850 42,000 55,000

208,000 126,000

34,000

41,000

430,000 185,000;

not measured

U)

Table I continued

Attempt no.

11

12th

σ> ο co co

Alcohol bc'i S. Alcohol 8 C: S. Alcohol 10 c ¹ p Alcohol 12 c ¹ p Alcohol 14 c ¹ p Alcohol 16 c 'S Alcohol 18 c • s Alcohol 20+ C ¹ S Alcohol 22+ c's Alcohol 12c ' s + l8c's Alcohol l4c s + l8c's Alcohol l6c ' s + l8c's % Sales Reactor approach

Walls stirrer shaft baffle bottom coagulum,% scraped off,% Sedimentation,% 1 hour

4 hours

1 day 4 days slurry pH surface tension Total solids,%

2.1

89

1/16 "1/16"

1 / 16-1 / 8 "1/16"

0 0.07

0 0 0 0 9.2

36.0 40.5

2.1

1/16 "

1/16 "

1 / 8-1 / 4 "

1/16 "

0.4

0 0 0 0

3 <3 *. 8th
39.8

2.1

86

3 / 8-5 / 8 "1 / 2-3 / 4" 1 / 2-1 "3/8"

0.75 2.0

0 0 0

39.8 39

2.1 88

1 / 16-1 / 8 "1/8" 1/8 "1/16" or 0.04

8.9 26.9 4o.o

2.1 85

1/16 "

1/4 "stained

1/4 ⁷¹

1/8 "O.OOl <0.001

0 0 0 0

8.8

29.2 39.5

2.1 86

1/16 "I / 16" 1/16 "I / 16"

0 <0.001

0 0 0 0

9.6 32.5 39.0

CD ed 00

Table I continued Plastisol mixture

Brookfield RVF viscosity, cps Z 1o

11

CO CO OJ

initially V ₉ ^V .2o

1 day 1 week

v:

V V V

2o

2o

14,500 24,000

ΙδΟ, ΟΟΟ 85,000 not

measured

7,000

3,950

25,000

10,750

56,000

24.200

5,000 not 8,700 9.4oo gemes 6.620 18,500 sen 26,000 9,7oo; 16,500 72,000 25,000

14,000

7.770

126,000

30,700

CD HO 00 CO

As can be seen from the above results, the improved new properties of the products according to the invention are not satisfactory obtained until the chain length of the alcohols is 14 carbon ■■ atoms reached. It is also found that a significant reduction in polymer deposition or des Polymer approach is observed. These experiments clearly demonstrate the advantages of the present invention.

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Claims (9)

-17 claims 1 / Process for the preparation of polymers of vinyl halides and vinylidene halides and copolymers thereof with each other or either with one or more vinylidene monomers having at least one terminal CH ₂ = C <group, characterized in that _r forming a monomer premix containing the monomer to be polymerized or the monomers to be polymerized, the aqueous reaction medium, a catalytic amount of a catalyst suitable for the reaction, an ammonium salt of a saturated fatty acid having 8 to 20 carbon atoms and at least one long-chain saturated alcohol having 14-24 carbon atoms and the ratio of alcohol to fatty acid being the same or greater than 1.0, the premix is homogenized at a temperature which is below the reaction temperature of the catalyst (s) used, the homogenized premix is transferred to a reaction zone, the homogenized premix in this reaction zone of the emulsion polymer ation at ice: temperature in the range of about 30 ° to about 70 ° C, the pH in the reaction zone in the range of about 7, ο to about 12, ο maintained until the reaction is complete and then the polymer or copolymer wins. 2. The method according to claim 1, characterized in that the ammonium salt is ammonium laurate. 3. The method according to claim 1, characterized in that that the monomer in the premix is vinyl chloride. 4. The method according to claim 1, characterized in that the ammonium salt in situ in the monomer premix is formed by adding the fatty acid and an excess of the equimolar amount to the premix 609 8 83/1136 Smmoniunthydroxyd gives. 5. decay according to claim 4, characterized that the fatty acid is lauric acid. 6. The method according to claim 1, characterized in that t ciaß the catalyst t-butyl peroxypivalate is. 7. The method according to claim 1, characterized in that that the long chain saturated alcohol has 16 carbon atoms contains. 8. The method according to claim 1, characterized in that that the ammonium salt is ammonium stearate. 9. The method of claim 1, characterized in that the catalyst Laurylperoxyd r is. la. Method according to claims 2-9, characterized in that that ^ he pH in the reaction zone in the range from about 8, ο to about 1o, 5. Method according to claims 1 - 1o, thereby ge indicates that the temperature in the homogenization level 25 ^W C is. Method according to claims 1-11, characterized ge indicates that the temperature in the reaction zone 45 ° C. 609883/1136