NO142082B - FRGM FOR FR.ST. OF A HUGE EMULSION OR DISPERSION OF A PART. AQUATIC MATERIAL, AND EVENT. FURTHER CONVERSION OF IT FORWARD. Disp. OR EMUL. FOR A POLYMER DISPERSE. TO DELV. Anhydrous. MATERIAL IS A POLYMERIZER MONOMER - Google Patents

Description

The present invention describes a method for producing aqueous emulsions or dispersions of a partially water-soluble material or mixtures of partially water-soluble materials, and possibly further polymerization when the partially water-soluble material is a monomer or a mixture containing one or more monomers.

In Norwegian patent 139,410, which describes a method

for the production of emulsions of somewhat water-soluble vinyl monomers,

it has been shown that stable emulsions of vinyl monomers can be produced by, in a first step, producing an aqueous preemulsion of a very slightly water-soluble material by an effective homogenization process and then, after the addition of water and emulsifier, allowing the slightly water-soluble viayl monomer to diffuse into the droplets of the very little water-soluble material. The fact that the droplets in the preemulsion consisted of a material that combined very low water solubility and low molecular weight led to the droplets being able to absorb 50-500 times their own volume of the somewhat water-soluble vinyl monomer, forming stable dispersions that were subjected to polymerization for to form a latex. In this case, the preemulsion was produced by homogenization, which leads to a broad distribution of the droplet size, which became even wider after absorption of vinyl monomers: h^~

According to Norwegian explanatory document 141,367, a dispersion of particles has been produced by ordinary emulsion polymerization, but unlike ordinary polymer, the particles contain a significant fraction of oligomers with a much lower molecular weight. This means that the particles can take up 20-200 times their own volume of a somewhat water-soluble substance. In order to achieve the formation of low molecular weight oligomers by ordinary emulsion polymerization, according to explanatory document 141.36 7, the addition of chain transfer agents during the polymerization is used, which results in the formation of short chains.

Both with the method described in patent 139.410 and in explanatory note 141.36 7, one obtains in a first step a preemulsion of particles which have the ability to take up a somewhat water-soluble material in an amount of 10-200 times more than corresponding polymer particles.

The method described in explanatory document 141,367 avoids the homogenisation of the very slightly water-soluble substance with a low molecular weight which is mentioned in patent 139,410. Furthermore, the method described in specification document 141,367 provides greater possibilities for the production of more monodisperse particles with a predetermined size. However, a disadvantage of the method described in explanatory document 141.36 7 is that the chain transfer agent, which will usually be a mercaptan compound, is a strong-smelling, partially toxic compound that is unpleasant to work with. Furthermore, addition of this often leads to a reduction in the polymerization rate. Furthermore, it is required that the chain transfer agent be added in portions or continuously during the polymerization in order not to obtain a too broad distribution of molecular weight and too large a proportion of high polymer material.

According to the present invention, aqueous dispersions of particles are produced which, in addition to polymer molecules, contain a considerable part of one or more low-molecular, very poorly water-soluble materials, hereinafter called Substance I, and which therefore have a far greater ability than particles of pure polymer to absorb a partially water-soluble substance,

hereinafter called Substance II, which is added in the next step.

In specification document 141,367, particles containing 10-100% water-insoluble oligomer are produced by adding a chain transfer agent during the polymerization of the monomer that forms the basis of the particles..,

According to the present invention, Substance I as such is introduced into the particles. This happens during or after the production of polymer particles by emulsion polymerization by ensuring that Substance I can diffuse through the water phase and become absorbed in the particles. The procedure is carried out as stated in claim 1.

In a first step, an aqueous dispersion of particles or droplets is thus produced which, in addition to polymer, contains a relatively low molecular weight water-insoluble substance I, and these particles will, as mentioned, be able to absorb a very large amount of a partially water-soluble substance II which under the given conditions can diffuse through the water phase and become absorbed in the particles consisting of polymer and Substance I.

In that in the first step particles have been produced which

in addition to the polymer containing Substance I, particles have been formed which are able to absorb the partially water-soluble Substance II which can diffuse through the water phase to the particles and become absorbed in them. In the second step, one will thereby be able to achieve

a volume ratio between Substance II and particles that is 5-100 times greater than what is the case with particles of pure polymer.

The Substance II used can be any partially water-soluble substance that can diffuse through the water phase. It can e.g. also be a monomer or a mixture of a monomer and another Substance II.

In the event that Substance II, which is added in the second step, comprises a monomer, this can be polymerized after it has been absorbed into the particles. In this case, the present method represents a special form of seed technique.

Current progress

method is particularly suitable when one wishes to produce dispersions with a particular predetermined particle or droplet size and size distribution including monodisperse droplets or particles and polydisperse systems where within the individual fractions one has a very uniform particle size. Monodisperse emulsions are very difficult to produce by ordinary emulsion processes. Likewise, it is very difficult to produce directly monodisperse polymer dispersions with particle sizes cfi/er 1 ym. For a number of purposes it is desirable to produce larger particles with a uniform particle size, e.g. as a standard in microscopy, as model systems by separation.^ "fluid flow" centrifugation, diffusivity measurement and dust investigations. Furthermore, the particles can be used in electrokinetic studies, and also in photo-technology, for example as a layering agent for X-ray film. They can also be used in biomedicine as an aid in diagnosis and

detection of antigens and antibodies in biological fluids.

Likewise, it may be desirable to have a predetermined size

and size distribution in dispersions of active substances with e.g. biochemical action such as pesticides. Furthermore, for special paint dispersions, a predetermined particle size distribution will be desired. The same is the case with PVC dispersions. Monodisperse particles can also be used as a dulling agent for paint and for powder coating. They will too

could be used as a toner in xerography. Furthermore, the particles in dry form can be used for tribological purposes. By using as Substance II a mixture of a partially water-soluble solvent, a vinyl monomer and a vinyl monomer, polymerisation and solvent stripping can be carried out after swelling in a manner known per se to obtain porous particles which are suitable for separation purposes . By using as Substance II a monomer or monomer mixture and a low-boiling substance, the present method can be used for the production of expanding microspheres. Large monodisperse particles can also be used in the production of material for ion chromatography, where it is preferred that the particles are monodisperse in order to obtain a minimal pressure drop in the column.

For the above purposes, according to the invention, an aqueous dispersion of polymer particles can be prepared by ordinary emulsion polymerization and then with a special treatment of these particles increase their ability to take up a partially water-soluble material, Substance II. When producing the polymer particles according to usual principles, it will then be possible to regulate the size and size distribution of the particles within wide limits. By subsequent addition of the partially water-soluble material, dispersions of this material would then be produced with droplet sizes that are uniquely determined by the size of the pre-coated polymer particles and the amount of Substance II absorbed in the particles. According to the present invention, up to 800 times the polymer particles' volume of the partially water-soluble materials can be absorbed in pre-coated polymer particles by this two-stage swelling process.

By the procedure

according to the invention, in the first step the polymer particles are swollen with the very slightly water-soluble low-molecular material, Substance I. Substance I has a molecular weight of <5000, preferably <500,

and a water solubility of <10 4 , normally <10 4 , preferably

<10~<5> g/l H2O. In order to get the very slightly water-soluble Substance I transported through the water phase and into the particles, it is necessary to carry out the first step under conditions that facilitate this transfer of Substance I. The transfer can be facilitated in several ways.

A finely divided aqueous emulsion of Substance I can be prepared which is added to the dispersion of polymer particles. This distribution will facilitate the transfer by increasing the interface with water. This fine distribution of Substance I can be produced by using relatively large amounts of emulsifier or emulsifier mixtures that directly give finely divided emulsions, possibly microemulsions, or in special cases, mixed micelles and/or using intensive homogenization of Substance I, water and emulsifier.

The first step may possibly include the swelling

of the polymer particles in the first step with Substance I takes place continuously during the actual production of the polymer particles.

This can be done by Substance I being present during the production of the polymer. It is then preferably mixed with the monomer or monomer mixture from which the polymer is produced, and an initiator is also used. In order for Substance I to diffuse into the polymer particles as they are formed, the polymerization is carried out under conditions that allow transport of Substance I through the water phase. A method that will greatly facilitate the transfer of Substance I to the particles involves adding a certain amount of a material which is a solvent for Substance I in the first step

and at the same time completely or partially soluble in water.- This will increase the rate of transfer of Substance I to the particles by increasing the solubility in the aqueous phase. Examples of such solvents are acetone and lower alkanols. In the event that the monomer or one of the monomers in a monomer mixture used for the production of polymer particles into which Substance I is to be introduced is relatively water-soluble, the monomer itself can serve as such a solvent. Examples of such relatively water-soluble monomers are vinyl acetate, acrylic acid, acrylonitrile, methyl acrylate and acrylamide, which are then polymerized in a subsequent step. Normally, said solvents are used in an amount of 1-100% of the amount of water, based on volume.

One can also advantageously use a combination of the above-mentioned methods which will include the production of Substance I in finely divided form and the use of excess emulsifier or the addition of a solvent miscible with water in the first step.

In cases where the polymer particles' glass transition temperature, Tg, is above the temperature at which Substance I is introduced, the diffusion of Substance I into the polymer particles themselves

be speed-determining. In this case, it could be an advantage to have a small amount of a substance present in the particles before introducing Substance I, which will lower the Tg of the particles. This can e.g. is done by allowing the original polymer particles to contain a significant amount of unreacted monomer, or during the production of the original polymer particles, a substance is present that is sufficiently water-soluble for it to diffuse into the polymer particles as they are formed. The substance can also be absorbed in prefabricated polymer particles. This substance only has the task of lowering Tg and thus facilitating the transport of Substance I into the particles themselves.

The transfer of Substance I to the polymer particles in the first step, so that these are swollen with Substance I, can be carried out in several ways. Polymer particles are thus produced which contain Substance I in an amount of e.g. up to 10, normally 0.05-5, in particular 1-4 times the amount of the polymer, based on volume. An important point in the method described here is that, before a somewhat water-soluble substance II is added in the second step, which is to diffuse into the polymer particles, the conditions are changed so that while substance II can diffuse through the water phase into the polymer particles, in this second step in the process transport of Substance I through the water phase is effectively prevented so that none of Substance I will be able to diffuse out of the polymer particles. Particles that are swollen with Substance I will be able to absorb up to 1000, normally up to 800, especially 20-300 times their original volume of Substance II. The strong reduction in transport of Substance I out of the particles before Substance II is added, which is a prerequisite for the method to work, will partly occur naturally when water is added before substance II is added. As particles containing Substance I must be added up to 800 times their original volume with Substance II, it will be necessary to dilute with water, depending on the desired concentration in the finished dispersion. If a dispersion is thus desired where the ratio between water and substance II is 1:1, water is added in step 2 in such an amount that tota], amount of water is the same as the amount of substance II added in step 2. Normally, the ratio between water and Substance II in the finished dispersion be from 95:5 to 20:80. Before adding this amount of water, you have a relatively high concentration of the substances that have been added to facilitate transport

of Substance I into the particles. By adding the large amount of H20

in the second stage, the concentration of the mentioned substances will be greatly reduced, and thus the possibility of transporting Substance I out of the particles will also be greatly reduced. When using, for example, acetone to produce an easier transport of Substance I into the particles in the first step, it will be advantageous to evaporate this before adding waterj + Substance II in the second step. It is an essential point of the present invention" for the production of dispersion of Substance II, that the addition of Substances I and II takes place in two steps so that Substance I is absorbed in the particles in a first step where conditions exist that make transport of Substance I possible , while Substance II diffuses into the particles under conditions that prevent the transport of Substance I through the water phase. Thus, it will be found that if you first mix Substance I and II and then add this to an aqueous dispersion of the polymer particles, and by adding e.g. acetone ensures that both Substance I and Substance II can be transported through the water phase to the particles, then both Substance I and Substance II will be taken up, but the total amount taken up would be limited to 1-4 times the volume of the particles.

When the ratio between water and Substance II is lower than 50:50, it may be advantageous to add Substance II in portions or continuously over a certain period of time.

Any material or mixture of materials that possesses the given properties, very low water solubility and relatively low molecular weight can be used as Substance I. It is also an advantage that they are non-crystalline at the temperature at which they are introduced into the particles. It is also an advantage that Substance I is in liquid form at the temperature at which Substance II is introduced into the particles in the second step, as in this case you not only get the mentioned greatly increased absorption capacity for Substance II, but also often a very strong increase in absorption rate. This is particularly the case where one operates with a polymer in the starting particles where the glass transition temperature is above the temperature mari" uses during swelling with Substance II.

In the event that Substance II is a vinyl monomer which, after diffusion into the particles containing Substance I, is to be polymerised, it could be advantageous to use as Substance I, in whole or in part, a water-insoluble vinyl monomer which can be copolymerised with the vinyl monomer added in the second step. Examples of vinyl monomers that satisfy the above-mentioned requirements for Substance I are stearyl vinyl ether and stearyl methacrylate.

When the partly water-soluble Substance II is wholly or partly monomeric, which after diffusion into the particles polymerises into a polymer, the present invention represents, as mentioned, a form of seed technique which is often described in the literature for the production of latexes. In the usual seed technique, a latex is produced by the usual method of emulsion polymerization, and this latex is used as a seed. "Monomer, water, emulsifier and initiator are added to this seed and the polymerization continues. A latex is then formed with larger particles than in the original seed latex. It is ensured that the polymerization takes place inside the seed particles, so that new formation of particles in The weakness of the conventional seed method is that the seed particles, which consist of polymer molecules as described above, can only occupy 1-4 times their own volume.

Do you want to e.g. from 10 g of seed particles to produce 500 g of latex particles, this must therefore be done in several stages with the gradual addition of emulsifier. The 10 g of seed particles will only absorb up to 40 g of monomer. This only gives a small increase in surface area, and

as you do not want too much emulsifier in the water phase, you must limit the amount of emulsifier to an amount that is adsorbed on the surface of the swollen seed particles. After polymerization, more monomer and emulsifier are added again, and the process is repeated.

It will be obvious that this will require several steps before one

has received 500 g of latex particles.

In that, as in the present invention,

using seed consisting of polymer + Substance I, the seed particles can absorb much larger amounts of monomer, often all the monomer can be added in one step, and the amount of seed used can be greatly reduced. When producing very large particles, it may be required that the process of swelling with monomer, possibly also with Substance I and initiator, is repeated. The larger the starting particles, the more Substance I can be introduced into them. In any case, the number of steps is greatly reduced compared to what would be necessary when producing particles of the same size in a normal seed process. The swelling of the particles with the large amount of monomer further leads to a very large increase in surface area. This means that even if you add all the emulsifier from the start, this will be adsorbed to a very high degree on the surface of the swollen particles, and there is little emulsifier left in the water phase, so that the formation of new particles in the water phase will not occur.

As an initiator for polymerization, water-soluble initiators such as K2S2Og or H2°2" can be used. These are then preferably added after swelling with monomer. An oil-soluble initiator can also be used. When using an oil-soluble initiator that is somewhat soluble in water, such as azobisiso -butyric acid nitrile (AIBN), this can be added after diffusion of monomer or dissolved in the monomer before diffusion into the particles. With oil-soluble initiators that are less water-soluble, such as lauroyl peroxide, it will be necessary to add this at the same time as Substance I then relatively then, as described above, is such that even very slightly water-soluble substances can be transported through the water phase.

Initiators possessing combination of low solubility

in water and low molecular weight, will also be able to act as Substance I. It has been shown that certain special initiators which are liquid at the relevant temperatures are particularly favorable as Substance I. They can be easily introduced into the particles according to the methods described above . This will be particularly relevant when Substance II is a monomer, as such initiators act like Substance I, and furthermore they will serve as initiators for polymerization of Substance II. An example of such an initiator is dioctanoyl peroxide.

Oil-soluble initiators that have a very low water solubility such as e.g. dioctanoyl peroxide, it has the advantage over more water-soluble initiators such as e.g. AIBN, that they not only reduce the risk of new formation of particles in the water phase, but also reduce the risk of bulk polymerization. With the latter oil-soluble - but also somewhat water-soluble - initiator, it is an absolute prerequisite that all monomer is absorbed in the particles before the polymerization is started by raising the temperature. Likewise, with this initiator care must be taken that a monomer phase is not formed by evaporation and condensation of monomer during the polymerisation. Oil-soluble initiators such as AIBN are sufficiently water-soluble that they will diffuse into the possible monomer phase and start a bulk polymerization which will lead to the formation of large lumps and thereby entail major disadvantages. When using a very poorly water-soluble initiator such as dioctanoyl peroxide,

the eventuality that not all the monomer added in the second step is absorbed will not have the same significance as the initiator is so

poorly water-soluble that it will not diffuse out of the particles through the water phase into the eventual monomer phase. If therefore intermediate

if a certain monomer phase is present during the polymerization, nothing else will take place in it other than possibly thermal polymerization, and monomer will mainly be absorbed into the particles with initiator as the polymerization progresses.

With such a very slightly water-soluble, oil-soluble initiator, one can therefore, if desired, also swell and polymerize in several stages at the polymerization temperature without having to lower the temperature before each swelling process with monomer, in order to prevent bulk polymerization. Likewise, for the same reason, it is possible to add vinyl monomer continuously during the polymerization. In these cases too, it is an advantage that Substance I (which in this case is the initiator) is liquid at the appropriate temperature, so that the uptake rate of monomer in the particles increases. The use of dioctanoyl peroxide or other initiators that are highly soluble in water alone or together with another Substance I which is not an initiator has proven to be very suitable for the production of monodisperse particles with a high particle size.

When producing large monodisperse particles according to the present invention, one starts with a seed of relatively small monodisperse polymer particles which, as described above, is added to Substance I and then monomer which is then polymerized. The starting seed is produced by ordinary emulsion polymerization under conditions that give monodisperse particles. Such methods are well-known in the literature, see e.g. Woods, M.E., Dodge, J.S. and Krieger, I.M., J. Paint Techn. 40, 541 (1968).

These methods, which are all variants of ordinary emulsion polymerization, are satisfactory for the production of monodisperse particles with a diameter of up to approximately 0.5 µm. Monodisperse particles with a diameter of over 1 µm are difficult to produce by these methods and monodisperse particles over 2 µm cannot be produced by ordinary emulsion polymerization. With the method according to the present invention, it has proven possible to produce monodisperse particles with a very small standard deviation, with a diameter of - 5 µm.

The advantages of the present method compared to conventional seed methods are thus as follows: The presence of Substance I in the seed particles results in an enormous increase in the ability of the seed particles to swell with monomer. You can thereby reduce the amount of seed used. Furthermore, the increased degree of swelling will lead to a very large increase in the particles' surface. This also increases the adsorption capacity of the emulsifier, so that all emulsifier can be added from the start without the risk of having so much emulsifier in the water phase that new particles are formed there. In the case of normal seed polymerization,

one adds the emulsifier continuously or stepwise in order to

avoid new formation of particles in the water phase.

By being able to use such a small amount of seed, it will

could be of no importance for the properties of the finished polymer dispersion which monomer is used in the first step, and one can thus use a different monomer in the first step than the one added in the second step.

The present invention can be used for the production of dispersions of any partially water-soluble material and mixtures of such that can diffuse through the water phase, which will require that Substance II has a water solubility >10 -4 g/l H»0, preferably >10 -3g/ l ^0. The ratio between the solubility of Substance I and Substance II is of significant importance. Thus should

Substance II be at least 10 times, preferably at least 100 times as water soluble as Substance I. Thus, when Substance I has a water solubility of 10 -4g/l H„0, Substance II should preferably have a water solubility above 10 -2g/l ^0. If, on the other hand, it is desired to prepare a dispersion of a Substance II with a water solubility of 10 -4 g/l H_0, a Substance I with a water solubility of preferably below 10 -6 g/l H2O should be used.

It has been shown that even relatively very small amounts

of Substance I in polymer particles will be able to give a considerable increase in the ability of the particles to absorb Substance II compared to particles of pure polymer in the case that one has relatively large particles. Such a system with large particles containing relatively little of Substance I will, in addition to being produced from pure polymer dispersions, arise when, as described above, a process of swelling with monomer of particles with a relatively high content of Substance I has been carried out and then polymerized .

You have then obtained particles that are far larger than the original particles, that is, the amount of polymer is greatly increased, while the amount of Substance I is the same as before the process of swelling and polymerisation. It has been shown that even with a quantity of

about. 5% of Substance I calculated on polymer will particles with a diameter of approx. 2 ym could take up a quantity of Stoff II which in volume is approx. 40 times higher than the polymer particles.

Example 1

77 ml H 2 O, 13.5 ml 1-chlorododecane and 0.2 g Na-lauryl sulfate (NaLS) were homogenized in a two-stage Manton Gaulin homogenizer., 2 2

model 15 M, with 200 kg/cm in the 1st stage and 80 kg/cm in the 2nd stage for 1-1.5 min. This gave an emulsion with a droplet diameter of approx.

0.1-0.2 ym. This emulsion was added to seed latex of monodisperse polystyrene with a particle diameter of 0.65 µm (determined by electron microscopy). 83.8 ml of seed latex containing 77 ml of H 2 O + 6.8 ml of polystyrene particles were used. Furthermore, 6 ml of H 2 O and 18 ml of acetone were added with normal stirring at 35-40 C. After stirring for 10 hours at 40° C, acetone was removed by evaporation under vacuum. The emulsion was examined under an optical microscope, and one had a monodisperse emulsion with a droplet diameter of approx. 0.9 ym.

After evaporation of acetone, 1.0 g of Na-lauryl sulfate was added

and 840 ml H20 so that you had a total of 1000 ml H20. 800 ml of chlorobenzene was then added with normal stirring at 30 C. After 60 min. stirring at 30°C all the chlorobenzene had diffused into

the drops. The emulsion was examined under an optical microscope and it turned out that a monodisperse emulsion with a droplet diameter of approx. 3.0 ym.

Example 2

The experiment was carried out as described in example 1 with the difference that 35 ml of acetone was used. With this increase in the amount of acetone, the stirring time for introducing 1-chlorododecane could be reduced to <k 5 hours.

Example 3

Swelling of monodisperse polystyrene latex with chlorododecane was carried out as described in example 1. After evaporation of acetone, 1.0 g of Na-lauryl sulfate and 840 ml of H 2 O were added so that a total of 1000 ml of H 2 O was obtained. 800 ml of ethylbenzene were then added at 30°C with regular stirring. After 60 min. all the ethylbenzene had diffused into the droplets. Examination in an optical microscope showed a monodisperse emulsion with a droplet diameter of approx. 3.0 ym.

Example 4

350 ml H20, 13.5 ml 1-chlorododecane and 6 g Berol 09

(nonylphenol ethoxylate with 10 mol of ethylene oxide per mol of nonylphenol)

was mixed with a high-speed mixer of the Ultraturrax type for approx.

15-20 min. at 10,000 rpm. This gave an emulsion with a droplet diameter of 0.2-C.5 ym. This emulsion was then added to the same type and quantity of polystyrene seed latex as described in example 1. Then 47 ml of acetone was added with normal stirring at 35-40°C. After stirring for 10 hours at 40°C, acetone was evaporated under vacuum. Examination in an optical microscope showed a monodisperse emulsion

with drop diameter 0.9 ym. After evaporating the acetone, 1.0 g of Na-lauryl sulfate and 573 ml of hydrogen peroxide were added, so that a total of 1000 ml of H20 was obtained. 800 ml of ethylbenzene were then added with regular stirring at 30°C. After 60 min. mixing at 30°C

all the ethylbenzene had diffused into the droplets. Examination in an optical microscope showed a monodisperse emulsion with droplet

diameter 3.0 ym.

Example 5

75 ml of H 2 O, 15 ml of dioctyl adipate and 0.75 g of Na-lauryl sulfate were homogenized as described in Example 1. This emulsion was added to a seed latex of bidisperse polyvinyl chloride with particle diameters of 0.2 and 0.8 µm (determined by electron microscopy). 24.3 ml of seed latex was used, which contained 16.8 ml of H20 and

7.5 ml polymer particles. Furthermore, 10 ml of acetone was added with regular stirring at 35-40°C. After stirring for 10 hours at 40°C, acetone was removed by evaporation under vacuum. The emulsion was examined under an optical microscope, and one had a bidisperse emulsion with droplet diameters approx. 0.25 and 1.1 ym. After evaporation of acetone, 1.8 g of Na-lauryl sulfate and 908.2 ml of H20 were added

so that you had a total of 1000 ml of H20. Furthermore, 660 ml of dichloroethane were added at 30 C with regular stirring. After 60 min. stirring at 30°C, all the dichloroethane had diffused into the droplets. The emulsion was examined under an optical microscope, and it was found to have a bidisperse emulsion with droplet diameters of 0.8 and 3.5 µm.

Example 6

330 ml of H20, 10 ml of chlorododecane, 10.5 g of Berol 09 (nonylphenol ethoxylate with 10 mol of ethylene oxide per mol of nonylphenol) were mixed with a high-speed mixer of the Ultraturrax type for approx. 15-20 min. at 10,000 rpm. This gave an emulsion with a droplet diameter of 0.2-0.5 µm. This emulsion was added to the same seed latex as described in example 1. 248.6 ml of seed latex containing 228.6 ml of H 2 O + 20 ml of polystyrene particles were used. After stirring for 15 hours at 40°C, 421.4 ml of H20, 2 g of NaLS were added

and 800 ml of chlorobenzene. After 60 min. stirring, all the chlorobenzene was diffused into the droplets. The emulsion was examined under an optical microscope and it turned out that a monodisperse emulsion with a droplet diameter of 2.1 µm had been formed.

Example 7

77 ml of H 2 O, 11.7 ml of chlorododecane, 1.8 g of benzoyl peroxide, 9.3 ml of dichloroethane and 0.2 g of Na-lauryl sulfate were homogenized as described in Example 1. This emulsion was added to the same type and amount of seed latex as given in example 1. Furthermore, 6 ml of H2O and 8.5 ml of acetone were added with regular stirring at 35-40°C. After stirring for 12 hours at 40°C, acetone was removed by evaporation under vacuum. After evaporating the acetone and dichloroethane, 1.0 g of Na-lauryl sulfate and 840 ml of H20 were added so that a total of 1000 ml of H20 was obtained. Furthermore, 275 ml of dist. styrene under normal stirring at 30°C. After stirring for 2 hours at 30°C, the temperature was raised to 60°C and the polymerization started. After 25 hours of polymerization, a monodisperse latex with a particle diameter of approx. 2 etc.

Example 8

100 ml H 2 O, 20 ml dioctyl adipate, 0.5 g NaLS were homogenized as described in Example 1. This emulsion was added to a seed latex of a bidisperse polyvinyl chloride with particle diameters 0.1 and 0.3 µm (determined by electron microscopy). 45 ml of seed latex containing 35 ml of H 2 O and 10 ml of polymer particles were used. 15 ml of acetone were then added with regular stirring at 40°C. After stirring for 10 hours at 40°C, acetone was removed by evaporation under vacuum. After evaporating the acetone, 2.0 g of NaLS and 865 ml of H20 were added so that there was a total of 1000 ml of H20. Furthermore, 600 ml of vinyl chloride was added with regular stirring at 30°C. After stirring for 2 hours at 30°C, all the vinyl chloride had diffused into the droplets and 3.0 g of AIBN dissolved in 10 ml of dichloroethane was added. After stirring for 1 hour at 30°C, the temperature was raised to 50°C for polymerisation. The finished latex was bidisperse and contained particles with diameters of 0.3 and 1.0 µm.

Example 9

150 ml H 2 O, 30 ml dioctyl adipate, 0.75 g Na-lauryl sulfate were homogenized as described in Example 1. This emulsion was added to a seed latex of polyvinyl chloride with particles uniformly distributed from 0.1 to 0.3 µm. 60 ml of seed latex containing 45 ml of H 2 O and 15 ml of particles were used.

20 ml of acetone were then added with normal stirring at 40°C. After stirring for 10 hours at 40°C, acetone was removed by evaporation under vacuum. After evaporation of acetone, 2.25 g of Na-lauryl sulfate and 745 ml of H 2 O were added. Furthermore, 800 ml of vinyl chloride was added. After stirring for 2 hours at 50°C, 2.0 g of K2S2°8 in?)st 1 60 ml of H2° were added 0<? it was all polymerized.

The finished latex contained particles with diameters from 0.3-1.0 µm.

Oak sample 10

Monodisperse polystyrene latex with a particle diameter of 2.1 µm was prepared as described in Example 7. To 125.6 ml of this latex containing 100 ml of H 2 O and 25.6 ml of particles with 1.2 ml of chlorododecane, was added 3.0 g Na-lauryl sulfate and 900 ml H20 so that you had a total of 1000 ml H20. Furthermore, 900 ml of chlorobenzene was added with regular stirring at 30°C. After stirring for 2 hours at 30°C, all the chlorobenzene had diffused into the droplets. The emulsion was examined under an optical microscope, and it turned out that a monodisperse emulsion with a droplet diameter of approx. 6.5 cm.

Example 11

120 ml of styrene and 100 ml of chlorododecane were mixed and added to 1000 ml of H 2 O, 200 ml of methanol and 0.6 g of K 2 O 2 , and then polymerized at 60°C for 8 hours. The latex formed was monodisperse: with particle diameter 0.75 µm and with particles consisting of polystyrene and chlorododecane in the ratio 1:1.

180 ml of the formed seed latex, consisting of 150 ml of H 2 O and 15 ml of polymer particles swollen with 15 ml of chlorododecane, was added with 850 ml of H 2 O, 2.0 g of NaLS and 800 ml of chlorobenzene with regular stirring at 30°C. After 60 min. stirring at 30°C, all the chlorobenzene had diffused in. The emulsion was examined under an optical microscope and it turned out that a monodisperse emulsion with a droplet diameter of 2.25 µm had been formed.

Example 12

100 ml H2O, 9 ml 1-chlorododecane and 5 g NaLS were homogenized in a two-stage Manton Gaulin homogenizer, with 200 kg/cm<2>

in the 1st step and 80 kg/cm2 in the 2nd step for 1-1.5 min. This gave an emulsion with a droplet diameter of 0.1-0.2/µm. To this emulsion was added seed latex of monodisperse polybutyl acrylate with a particle diameter of 0 µm (determined by electron microscopy). 109 ml of seed latex containing 100 ml of H 2 O and 9 ml of polymer particles were used.

Furthermore, 20 ml of acetone was added with regular stirring at 35-40°C. After stirring for 3 hours at 35°C, acetone was removed by evaporation under vacuum. (Note that here the stirring time for introducing 1-chlorododecane was greatly reduced because a polymer with a much lower glass transition temperature than polystyrene was used.)

After evaporating the acetone, 800 ml of H 2 O were added

so that you had a total of 1000 ml of H20. 800 ml of chlorobenzene were then added at 30°C. After stirring for 2 hours, all the chlorobenzene had diffused into the droplets and examination under an optical microscope showed a monodisperse emulsion with a droplet diameter of approx. 1.4/Um.

Example 13

Seed latex of monodisperse polystyrene with a particle diameter of 0.5 µm (determined by electron microscopy) was swollen with a somewhat water-soluble compound, in this case toluene.

This was done to lower the glass transition temperature of the particles

and thereby facilitate the transport of Substance I in the particles.

A quantity of 99 ml of seed latex containing 91 ml of H20 and

8 ml of polystyrene particles were used. To this latex was added 0.05 g of Na-lauryl sulfate and 8 ml of toluene under normal stirring at 35°C.

After the absorption of toluene in the particles had taken place, the swelling with Substance I was carried out.

80 ml H2O, 8 ml 1-chlorododecane and 0.2 g Na-lauryl sulfate

was homogenized as described in example 1. This emulsion of Substance I was then added to the seed latex which had previously been swollen with toluene as described above. 10 ml of acetone was added and the mixture was stirred at 35°C. With this method, the time for complete absorption of Substance I into the particles was significantly reduced and was completed after less than 2 hours. After removal of acetone by evaporation, 829 ml of H 2 O, 2.75 g of Na-lauryl sulfate and 800 ml of chlorobenzene were added, and stirring was continued at 35°C. After stirring for 60 minutes, all the chlorobenzene had diffused into

the particles. The emulsion was examined under an optical microscope, and it was found that a monodisperse emulsion with a droplet diameter of

2.3 ym had been formed.

Example 14

50 ml H 2 O, 5 ml "Perkadox SE 8" (dioctanoyl peroxide) and 1.5 g NaLS were homogenized. "Perkadox SE 8" is an initiator with a melting point of 19°C, and due to its low water solubility this can act alone as substance I when swelling polymer particles.

After homogenization, the emulsion was added to the seed latex

of monodisperse polybutyl acrylate with a particle diameter of 0.3 µm (determined by electron microscopy), 60.5 ml of seed latex containing 55.5 ml of H 2 O and 5 ml of polymer particles were used. 10.5 ml of acetone were then added with regular stirring at 30°C. After stirring for 3 hours at 30°C, acetone was removed by evaporation under vacuum.

After evaporating the acetone, 894.5 ml of H20 were added so that there was a total of 1000 ml of H20. 200 ml of dist was further added. styrene under normal stirring at 30°C. After stirring for 2 hours at 30°C, the temperature was raised to 60°C and polymerization took place until complete conversion. A monodisperse latex with a particle diameter of approx. lyum.

Example 15

20 ml H20, 6 ml "Perkadox" SE-8 (dioctanoyl peroxide) and

0.2 g of Na-lauryl sulfate was homogenized as described in example 1. This emulsion was added to seed latex of monodisperse polystyrene .. which was prepared as described in example 7, with a particle diameter of 1.7 µm (determined by electron microscopy). 41 ml of seed latex containing 35 ml of H 2 O + 6 ml of polystyrene particles was used. Furthermore, 6 ml of acetone was added with regular stirring at 25-30°C. After stirring for 14 hours at 25-30°C, acetone was removed by evaporation under vacuum.

After evaporation of acetone, 1.5 g of NaLS, 1.0 g of "Berol 267" (nonylphenol ethoxylate, with 8 mol of ethylene oxide per mol of nonylphenol) and 945 ml of H20 were added so that a total of 1000 ml of H20 was added. 200 ml of dist was then added. styrene under normal stirring at 25-30°C. After stirring for 3 hours at 25-30°C, the temperature was raised to 70°C and polymerization took place until complete conversion. The finished latex was monodisperse and contained particles with a diameter of approx. 5 etc.

Example 16

35 ml of H 2 O, 4 ml of "Perkadox SE-8 (dioctanoyl peroxide), 3 ml of chlorododecane and 0.2 g of Na-lauryl sulfate were homogenized as described in Example 1. This emulsion was added to seed latex of monodisperse polystyrene which was prepared as described in Example 7 , with a particle diameter of 2 ym (determined by electron microscopy). 28.5 ml of seed latex containing 25 ml of H20 + 3.5 ml of polystyrene particles were used. Furthermore, 10 ml of H20 and 7 ml of acetone were added with regular stirring at 25-30°C After stirring for 14 hours at 25-30°C, acetone was removed by evaporation under vacuum.

After evaporation of acetone, 1.2 g of NaLS, 1.0 g of "Berol 267" (nonylphenol ethoxylate with 8 mol of ethylene oxide per mol of nonylphenol) and 9 30 ml of H 2 O were added so that a total of 1000 ml of H 2 O was obtained. 175 ml dist was then added. styrene under normal stirring at 25-30°C. After stirring for 3 hours at 25-30°C, the temperature was raised to 70°C and polymerization took place until complete conversion. The finished latex was monodisperse and contained particles with a diameter of approx. 7 etc.

Example 17

20 ml H2O, 6 ml "Perkadox" SE-8 (dioctanoyl peroxide) and

0.2 g of Na-lauryl sulfate was homogenized as described in example 1. To this emulsion was added seed latex of monodisperse polystyrene with a particle diameter of 1.7 µm (determined by electron microscopy) prepared as described in example 7. 41 ml of seed latex was used which contained 35 ml of H2O and 6 ml of polystyrene particles. Furthermore, 6 ml of acetone was added with regular stirring at 25-30°C. After stirring for 14 hours at 25-30°C, acetone was removed by evaporation under vacuum.

After evaporating the acetone, 1.5 g of Na-lauryl sulfate and 945 ml of H2O were added so that there was a total of 1000 ml of H20. Then 70 ml of dist. styrene under normal stirring

at 25-30°C. After 30 min. stirring at 25-30°C, the temperature was raised to 70°C. After polymerization for 2 hours at 70°C, addition of the remaining amount of monomer was started, 140 ml dist. styrene was added over 5 hours. The temperature in the autoclave was 70°C during the addition of the styrene. It was polymerized to full conversion and the finished latex contained particles with a diameter of approx. 5 ym with standard deviation approx. 0.5 ym.

In this example, only part of the monomer was added at the start, while the rest of the monomer was added after some time of polymerization.

Example 18

30 ml H 2 O, 6 ml stearyl methacrylate and 0.2 g Na-lauryl sulphate were homogenised as described in example 1. The temperature was kept at approx. 35°C during the homogenization. To this emulsion was added copolymer latex of styrene and butyl acrylate with a particle diameter of approx. 0.35 ym (determined by electron microscopy) and with a glass transition temperature of approx. 15°C. 36 ml of latex containing 30 ml of H 2 O and 6 ml of polymer particles were used. Furthermore, 6 ml of acetone was added with regular stirring at approx. 35°C. After mixing for 5 hours at approx. 35°C, acetone was removed by evaporation under vacuum.

After evaporating the acetone, 2.5 g of Na-lauryl sulfate and 940 ml of H2O were added so that there was a total of 1000 ml of H20. 210 ml of styrene was then added with normal stirring at approx. 35°C. After mixing for 2 hours at approx. At 35°C, 4 g of AIBN dissolved in a small amount of 1,2-dichloroethane was added. After mixing for 1 hour at approx. 35°C, the temperature was raised to 70°C and polymerization took place until complete conversion. The finished latex contained particles with a diameter of approx. 1 etc.

Example 19

An experiment was carried out with copolymer latex consisting of 2-ethylhexyl acrylate and styrene in a ratio of 1:1.5.

This latex has a glass transition temperature of 30-35°C, which provides an easier transport of Substance I into the particles compared to what you have with pure polystyrene particles with a glass transition temperature of 100°C. Dioctyl adipate was used as Substance I. 90 ml of H2O, 10 ml of dioctyl adipate and 0.25 g of Na-lauryl sulfate were homogenized in the same homogenizer as described in example 1. To this emulsion was added the above-mentioned copolymer latex with a particle diameter of 0.45 µm (determined by electron microscopy). 120 ml of seed latex containing 110 ml of H₂O and 10 ml of polymer particles were used. After stirring for 5 hours at 30°C, all the dioctyl adipate had diffused into the polymer particles. Dioctyl adipate (Substance I) has sufficient water solubility that with the described procedure of producing a finely divided emulsion of the same, it is achieved that Substance I is transported from an emulsion of Substance I into the particles in a reasonable time, even without the addition of a water-soluble solvent. After indiffusion of dioctyl adipate, 2.25 g of Na-lauryl sulfate and 800 ml of H 2 O were added, so that there was a total of 1000 ml of H 2 O. 500 ml of chlorobenzene were then added with regular stirring at 30°C. After 60 min. stirring at 30°C, all the chlorobenzene had diffused into the droplets. Examination in an optical microscope showed a monodisperse emulsion with a droplet diameter of approx. 1.7 cm.

Claims (11)

1. Method for producing an aqueous emulsion or dispersion of a partially water-soluble material, and possibly further conversion of the produced dispersion or emulsion into a polymer dispersion when the partially water-soluble material is a polymerizable monomer, characterized in that in the first step one or more very slightly water-soluble -2 materials, designated as Substance I, with a water solubility <10 , -4 -5 normally <10 , preferably <10 g/l H.,0 and with a molecular weight of <5000, preferably <500, to an aqueous dispersion of polymer particles or to an aqueous dispersion of monomer or monomer mixture from which polymer particles are produced in the presence of Substance I , under conditions which lead to a strong increase in the transport rate of Substance I through the water phase to the particles which are thereby swollen by this upon stirring, the polymer particles being produced or produced in a manner known per se, after which, in a second step, the partially water-soluble material , designated as Substance II, is added under conditions where transport of Substance I through the water phase is inhibited, e.g. by the addition of water, whereby Substance II diffuses into the polymer particles which are swollen with Substance I during stirring, after which eventual polymerization is produced if Substance II is a polymerizable monomer. 2. Method as stated in claim 1, characterized in that Substance I is added in the form of an aqueous emulsion. 3. Method as stated in claims 1 and 2, characterized in that in order to increase the transport of Substance I through the water phase in the first step, so much emulsifier is used that the concentration of emulsifier is above the critical micelle concentration, so that some or all Substance I loose micellar, and that this effect is removed before the addition of Substance II in the second step by diluting with water. 4. Method as stated in claims 1 and 2, characterized in that the first step is carried out in the presence of a solvent which is completely or partially soluble in water and is a solvent for Substance I. 5. Method as stated in claim 4, characterized in that acetone or a lower alkanol is used as said solvent. 6. Method as stated in claim 4, characterized in that a relatively water-soluble monomer is used as said solvent. 7. Method as stated in claims 4 to 6, characterized in that the solvent is used in an amount of 1-100% of the amount of water, based on volume, in the first step. 8. Method as stated in claims 4, 5 and 7, characterized in that the solvent is removed after the first step, e.g. by evaporation. 9. Method as stated in claims 1 to 8, characterized in that in the second step the amount of water in the dispersion of polymer particles which have been swollen with Substance I is increased, an emulsifier is optionally added, and the desired Substance II is added, preferably while stirring, in an amount of up to 1000, normally up to 800, in particular 20-300 times the amount of polymer in the particles from the first step, based on volume. 10. Method as specified in claim 1, characterized in that a liquid initiator is used as Substance I which, in addition to acting as Substance I, will act as an initiator in the polymerization of monomer introduced in the second step. 11. Method as stated in claim 10, characterized in that dioctanoyl peroxide is used as liquid initiator.