DE1642986A1 - Pressure as a granulating aid - Google Patents

Description

PRESSURE AS A GRANULATING AID (Addendum to the German patent application C 37 672 IVa / 12 g) Subject of the German patent application C 37 672 IVa / 12 g is a process for the granulation of sparingly or insoluble in water, for the formation of dust chemical substances that tend to disperse in water, such as metal salts, in particular metal soaps and pigments, according to the invention, the substances from their suspension in a temperate medium at temperatures above about 60 ° C, in the presence of In water difficult or insoluble organic compounds with a molecular weight of above 150, preferably above 200, and a softening point of below 1000C precipitates and the precipitate isolates and dries. The granulating aids often have a longer-chain, aliphatic radical.

Fatty alcohol esters in particular have proven to be useful as granulating aids Fatty acid esters of polyhydric alcohols, alkyd esters, ester waxes, fatty acid amides and Fatty acid alkylamides, fatty acid nitriles, alkylphenols, fatty ketones, mixtures of Mineral oils and liquid paraffins with metal soaps, fatty acid anhydrides and mixtures, that contain mineral oils or liquid paraffins and have a whip point of below 100 ° C. According to the invention, fatty alcohol ethers can also be used as Granulating aids-can be used. Among the fatty acid esters of polyhydric alcohols are in particular alkylene glycol esters including the polyalkylene glycol esters, where the alkyl radical is usually ethylene, suitable. One advantage of the procedure is in the use of esters that give the end product special properties, such as e.g. give higher stability.

A simple way of carrying out the method is that the granulating aids, in the presence of which the substances are precipitated, while stirring, an aqueous suspension of the substances at a temperature of over 60 ° C. is added.

In some cases it can also be advantageous to warm up first after the addition of the granulating aid. mostly the granulating aids are used in amounts of 3 to 25, preferably 10 to 20 wt.%, based on the granulate Fabric, used.

The use of the granulation process disclosed in C 37 672 The German additional application describes the granulation of halogen-containing polymers C 38 904 IVc / 39 b. The granulation aids used are preferably those substances used as a lubricant for processing plastics, especially polyvinyl chloride, are suitable. The subject of the German additional application C 39 466 IVa / 12 g is the use of metal soaps, especially ricinoleates, octoates and / or Versataten as a granulating aid. To carry out the procedure, the Granulating aid in aqueous distribution - emulsion, dispersion or suspension - the materials to be granulated, which are also present in aqueous distribution, added with stirring.

It has now been found that the granulation according to the invention Process can be accelerated and carried out at a lower temperature, if in addition to the already from German patent applications C 37 672 IVa / 12 g, C 38 904 IVc / 39 b and C 39 466 IVa / 12 g known granulating agents or organic, water-insoluble solvents are added during granulation. this is the Subject of the German patent application C 39 506 IVa / 12 g (addition to the German Patent application C 37 672 IVa / 12 g).

It is a method of granulating heavy in water or insoluble but dispersing chemical ones that tend to form dust Substances, characterized in that these substances are used with the help of suitable ones more organic Granulating aids that contain a hydrocarbon residue and their melting point It is above 40 ° C. together with organic, water-insoluble solvents Boiling points up to 135 0C or those solvents that are volatile with water vapor are granulated by adding the substance to be granulated, the granulating aid and slurried the solvents in water, heated with stirring until a granular precipitate has formed, then filtered off, optionally washed out and dries.

The solvents used are e.g. water-insoluble, aromatic, aliphatic or chlorinated hydrocarbons, alcohols, ethers, esters and ketones with boiling points up to 135 ° C., but preferably below 100 ° C., are possible, but also solvents with higher boiling points that are volatile with water vapor; signed solvent in detail, for example, aliphatic gasoline with boiling points of 80 - 100 ° C, methylene chloride, Trichlorethylene, carbon tetrachloride, benzene, toluene, xylene, cyclohexanol, cyclohexanone and nitrobenzene.

The process has a number of advantages: Granulation can at lower temperatures than in German patent applications C 37 672, C 38 904 and C 39 466. As the lowest temperature no longer 600C, but only about 400C required. The granulation time is through Addition of solvents reduced by half on average.

The granules become more even and move ~ nor. sometimes between 0.1 and 1 mm in diameter. With higher proportions of solvent you can also Granules with a diameter of 5 mm and above were obtained. Conversely, the diameter the granules can be reduced by increasing the stirring speed.

This process can be used with success to make synthetic resins such as Polyalkylenes, e.g. polyethylene, but especially polyvinyl chloride and its copolymers, to granulate.

It has also been found that it is possible to use polymers, in particular Polyvinyl halides, only with the addition of plasticizers and / or solvents to granulate.

Subject of the German patent application. C 42 061 IVc / 39 b is a Process for the granulation of halogen-containing polymers, characterized in that that one part of the polymers at elevated temperature in plasticizers and / or Dissolves solvents, slurries the rest of the polymers in water at low temperature, the solution of the polymers is stirred into the aqueous suspension and then for so long slowly heated until granulation has occurred.

The stirring is then stopped, water is added again and briefly Time heated to a temperature of 80 to 1000C. When using titanium with solvents these are evaporated with the water.

All customary plasticizers are suitable as plasticizers, in particular Phthalate plasticizers, as well as sebacic acid esters, adipic acid esters, and phosphate plasticizers and last but not least, polymer plasticizers.

The solvents used are those with boiling points between 30 and 2000C, preferably from 60 to 110 0C, and those solvents that react with water vapor are volatile.

The following may be mentioned: aromatic hydrocarbons, preferably benzene, Toluene, xylene, aliphatic hydrocarbons, esters such as butyl acetate, ketones, such as cyclohexanone, ethers, such as dibutyl ether or solvent mixtures, such as. B. from toluene and acetone. Chlorinated hydrocarbons, such as carbon tetrachloride, prove their worth when granulating emulsion polyvinyl chloride.

According to the method described in C 42 061, suspension and Emulsion polyvinyl chlorides of all common K values or suspension and emulsion polyvinyl chloride mixtures and optionally also copolymers containing halogen-containing polymers, granulated will. In particular, the method described in C 42 061 can also serve to ' to apply granulation from the suspension or emulsion.

This is particularly advantageous for the granulation of emulsion polyvinyl chloride, because the emulsifiers - which often interfere with later processing - in the Granulation are largely washed out.

According to the method described in C 42 061, the production of Hard PVC granules and soft PVC granules with any plasticizer content possible.

The amounts of plasticizer are between 10 and 100 parts per 100 Parts of resin, the amounts customary in practice are preferably used between 30 and 80 parts for every 100 parts of resin. The granulation is of course the one Amount of plasticizer used, which is desired in the finished soft granulate. with the in practice the usual amounts of plasticizer of 80 to 30 parts per 100 parts of PVC granulation succeeds according to the process described in C 42 061 with the aid the plasticizer alone without the aid of solvents.

With smaller amounts of plasticizer, solvents must then increasingly be used be added during granulation.

When granulating rigid PVC, from 10 to over 400 is used Parts of solvent to 100 parts of polyvinyl chloride, but preferably 100 to 200 parts. According to the procedure described in C 42 061, if desired, Additives such as stabilizers or lubricants are also granulated. This in Procedure described in C 42 061 is permitted so it, the processor ready-made, for the respective processing conditions in an optimal composition present, free-flowing granules as compounds with all additives, such as Plasticizers, stabilizers, fillers, antistatic agents, anti-flame agents, dyes etc. to make available.

To carry out the method described in C 42 061, a small part of the polyvinyl chloride, preferably 1 to 3, at an elevated temperature between 35 and 200 0C in the entire plasticizer or plasticizer / solvent mixture, dissolved. The remaining major part of the resin is separated in water, preferably at room temperature in 1 to 2 times the amount of water, based on resin, suspended. Afterward is heated with stirring until granulation occurs, which is generally mixed 40 and 60 0C is the case.

Then the stirring is stopped and heated to 80 to 1000C. If you work without a solvent, after a short heating time - already after 5 to 15 minutes -the finished granules are drained. Used with solvents granulated, this is advantageously evaporated with the water and recovered. The heating times are then correspondingly longer.

Finally, in the German additional application C 41 719 IVc / 39 b described how it is possible to use halogen-containing polymers with solvents and / or to granulate plasticizers without any part of the polymer in the plasticizers and / or solvents.

The subject of German patent application C 41 719 is a method for the granulation of halogen-containing polymers, characterized in that one the polymers, resins in suspension or emulsion are diluted with water, add solvent and / or plasticizer to this dilution with stirring, stir until flocculation occurs and at room temperature or with gentle heating on about 400C then continue to stir until a granular precipitate forms has formed.

For the granulation of emulsion polyvinyl chloride in particular before adding the solvents and / or plasticizers with 0.1-2, preferably 0.25 - 1.25, based on resin, of a salt from the alkaline earth group, des Aluminum or the heavy metals, calculated as a solid salt in the form of an aqueous one Solution added.

As a solvent for the granulation of E-PVC according to this process Those which swell with emulsion polyvinyl chloride or the emulsion polyvinyl chloride are preferably used gelatinize, for example aromatic hydrocarbons such as benzene, toluene, Xylene or chlorinated hydrocarbons such as carbon tetrachloride.

However, there are also non-gelatinizing solvents for granulation of emulsion polyvinyl chloride, e.g.

Esters such as butyl acetate, ketones such as cyclohexanone, ethers such as dibutyl ether, Alcohols such as n-butanol or aliphatic hydrocarbons such as petroleum ether; even Mixtures of the solvents mentioned can be used.

Used to granulate plasticizer-free emulsion polyvinyl chloride from 10 to over 400 parts of solvent to 100 parts of polyvinyl chloride, preferably but 100 to 200 parts. The granulating temperatures used must inevitably below the boiling point of the water and above the boiling point of the solvent used lie.

As a plasticizer for emulsion polyvinyl chloride granules containing plasticizers all customary plasticizers are suitable, in particular phthalate plasticizers but also sebacic acid esters, adipic acid esters, phosphate plasticizers, polymer plasticizers or esters of fatty acids and alcohols with 4-22, preferably 4-8, carbon atoms. Also chlorinated paraffins are alone or together with other plasticizers suitable for this procedure. The amounts of plasticizer can be chosen as desired and are between 10 and 100 parts per 100 parts resin, preferably 30 to 80 parts.

The plasticizers can be used alone or together with the solvents can be used to granulate emulsion polyvinyl chloride.

The method disclosed in C 41 719 is therefore special.

Importance for the granulation of plasticizer-free polyvinyl chloride, where pre-dissolving in the plasticizer in accordance with C 42 061 is not possible.

For the granulation of plasticizer-free suspension polyvinyl chloride Practically only those solvents that gelatinize as polyvinyl chloride are suitable, for example toluene.

The granulation of plasticized suspension polyvinyl chloride is preferably carried out according to that described in German patent application C 42 061 Process according to which a part of the halogen-containing polymer in the solvent and / or plasticizer is pre-dissolved.

Already in the main application C 37 672 and in the additional application C 42 061 it was pointed out that the method according to the invention can also be used on plastics such as polyolefins, e.g.

Polyethylene, polyacrylic compounds or copolymers and not is only applicable to halogen-containing polymers.

It has now been found in German patent application C 42 182, that the process disclosed in German patent applications C 42 06I and C 41 719 for the granulation of halogen-containing polymers not only on these, but also on other plastics are applicable, and that the plastics themselves as granulating aids can serve for themselves or for other plastics. Plastics or plastic mixtures, which can be granulated are: polyacrylic acids, polymethacrylates and their copolymers, Polyvinyls such as polyvinyl halides, polyvinyl acetates or their copolymers, polyolefins, such as polyethylene, polypropylene or polybutylene, Cellulose derivatives, polystyrene, polyesters, polyamides or polycarbonates.

In addition to these thermoplastics, certain thermosets are also suitable, such as phenol or cresol resins or epoxy resins. Also elastomers, such as unvulcanized Natural rubber or synthetic rubber types such as ABS (acrylonitrile, butadiene, styrene) or ABR (acrylic butadiene rubber) or chloroprene. Also polysiloxanes, polyurethane or polyethers etc. are suitable.

To carry out the process is plasticized plastics proceeded in such a way that one part of the polymers at elevated temperature in WBichmachern and / or solvents dissolves the rest of the polymers in at elevated temperature Slurries in water, the solution of the polymers is stirred into the aqueous slurry and heated slowly until granulation has occurred.

There are 1 to 10, preferably 5 to 7, of the polymers in the soft. doer and / or solvent pre-dissolved.

Also other substances that can be gelled in plasticizers and / or solvents can be used as a granulating aid; so z. B. Lithium stearate in Dioctyl phthalate or calcium stearate and / or barium stearate or aluminum stearate odar lithium stearate in mineral oil.

The better the plastic, the easier it is to granulate is soluble in the leveling agent or the solvent.

Aggregates such as stabilizers or lubricants can also be granulated so that the processor finished, for the respective processing conditions Free-flowing granules present in an optimal composition as a compound all additives such as plasticizers, stabilizers, fillers, antistatic agents, Anti-flame agents, dyes etc. can be made available.

Occasionally it is beneficial to do the auto granulation beforehand with the same Plastic, but of lower molecular weight. This goes Not only does it make granulation easier, it can also have other technical advantages can be achieved: Used as a granulating aid for the granulation of polyvinyl chloride For example, a polyvinyl chloride with a low K value, this increases the cold impact resistance elevated.

In the case of non-plasticized plastics, the solution11 takes place Granulating agents in suitable solvents in which the plastics, the serve as granulation aids, are soluble or at least swellable. As a solvent mainly those with boiling points of up to 135 ° C, but preferably below, are used 1000C or those solvents that are volatile with water vapor.

The procedure for granulating plasticizer-free plastics is advantageous according to C 41 719 so that the polymerized, in suspension or emulsion is located Resins diluted with water, then heated, preferably to a temperature above 80 ° C, the granulating aid is added to this dilution in the form of a melt and Stir until a granular precipitate forms, which is then sieved off and is dried.

So plastics with lower melting points are used for this purpose in question, respectively those plastics that are below the boiling point of water soften and can thus serve as granulation aids, especially low molecular weight ones Plastics such as low molecular weight polyethylene or polyethylene glycols.

If you granulate under pressure and thereby increase the boiling point of the water, this can also be used with correspondingly more highly softening plastics as a granulating aid to be worked.

In the process described in the application C 37 672 arise now PVC compounds in granulate form, which have a certain degree of gelation have, which is sufficient for all those applications in which in the Verarbeltungsmaseninen there is a certain minimum amount of friction, as is the case e.g. B in processing of PVC compounds according to the Sprltzguauerfahren is common, especially when High pressure machines are used.

However, the achievable degree of pre-gelation is not sufficient to ensure crystal clear Manufacture soft extrusion products and also when processing on single-screw machines cables must be controlled by appropriate temperature control using screw presses with a compression of at least 1: 4 and possibly also by installing additional ones Sieves ensure that the material in the processing machine dis required Energy is supplied for complete gelation.

As these measures increase in high-speed cable machines. an impairment of the discharge, it seemed desirable to use the granules before the processing into the end product the necessary for a better pre-gelation To supply energy in the form of thermal energy.

An attempt was made to do this 1.) by increasing the drying temperature, and 2.) by post-treating the granules formed under pressure in an autoclave to reach.

The increased drying temperature has the disadvantage that with plasticizer losses must be taken into account and that the material may be prone to burns. Oxidative and thermal loads during the drying process are dangerous with itself, the advantages of the method described in the main application C 57 672 with regard to the savings in stabilizers, at least in part, nullified again close.

It has now been found that these disadvantages do not exist when one works according to the procedure described under 2.) this is according to C 37 672 and additional registrations after completion of the granulation Normal pressure Preferably with stirring at a pressure between D5 to -, S atü and further heated over it. Temperatures of 110 to 180 ° C are reached during a treatment time Achieved from 20 seconds to 30 minutes. The temperature increase can also occur take place in a different manner, including heating in the high-frequency field according to the invention Swiss Patent No. 424 243 comes into question. Those made by this process Granules differ only slightly in their properties from full Gelled granules as they are on extruders, rollers and similar Granuiiefmaschinen be won. The granules treated according to this process result in finished articles with high transparency and a completely smooth surface, the output in the extruder is significantly higher than that of non-aftertreated granules.

The subsequent treatment according to the invention of the according to C 37 672 and the additional applications C 42 061, C 41 719 and C 42 182 produced granules suffice compared to granulation under pressure, as described in C 42 182, shorter times for pressure treatment. when there is mechanical stress on the material therefore lower, its final stability correspondingly higher.

Example 1 50.0 parts of S-PVC, 70/54 30.0 parts of dioctyl phthalate 0.5 Parts of BCR 02 (barium-cadmium stabilizer) 0.1 parts of BC 12 SL (barium-cadmium-5 stabilizer) That material from this formulation was granulated with pre-dissolved PVC in the suspension. A pressure treatment then followed in the aqueous phase with stirring. Of the The pressure was set to 5 atmospheres for 10 minutes (157.90C pressure-temperature equivalent) held. The PV & granules treated in this way were transparent and smooth Surface, while a granulate not treated under pressure has no transparency and had a wavy surface.

The PVC granules treated under pressure had a bulk density of 500 g / l. In contrast, a granulate that was not aftertreated under pressure had only a bulk weight of 365 g / l.

Example 2 50.0 parts of S-PVC 70/54 30.0 parts of dioctyl phthalate 0.5 part BCR 02 (barium-cadmium stabilizer) 0.1 parts BC 12 SL (barium-cadmium stabilizer) The material of this formulation was also granulated with pre-dissolved PVC in the suspension. A pressure treatment was then carried out in the aqueous phase with stirring. Of the The pressure was set to 5 atü (157.90C pressure-temperature equivalent) for 20 minutes. held. These PVC granules were transparent and had a smooth surface, while untreated PVC granules were without transparency and a wavy surface exhibited.

The bulk weight improved as a result of the prolonged pressure treatment of the PVC granules to 550 g / l. In contrast, one that had not been post-treated under pressure Granules only have a bulk weight of 365 g / l.

Example 3 (for cables) 40.00 parts S-PVC 17.15 parts diisononyl phthalate 9.00 parts chalk 1.00 part white lead 0.16 parts calcium stearate 0.28 tea paraffin oil The material of this formulation was granulated with pre-dissolved PVC in the suspension. The PVC granulate was put under pressure while still in the aqueous phase. This one was Maintained at 5 atmospheres (157.90C pressure-temperature equivalent) for 15 minutes and then after drying, the bulk density of the PVC granules is determined. It was 550-560 g / l, while a PVC granulate not treated under pressure has a bulk density of only 450-460 g / l.

The surface of the pressure-treated granules was completely smooth. In contrast, untreated granules had rough spots on the surface.

When processing in the extruder, the output was lower Pressure post-treated PVC granulate is approx. 25% higher than that of one not below Pressure compacted materials.

Claims (2)

Claims 1.) Method for granulating heavy in water or insoluble, powdery substances according to German patent applications C 37 672 IVa / 12 g, C 42 061 IVc / 39 b, C 41 719 IVc / 39 b and C 42 182 IVa / 12 g, characterized in that the granules formed are in an aqueous slurry preferably with stirring at a pressure of over 0.5 atm during a treatment time heated from 20 seconds to 30 minutes. 2.) Method according to claim 1, characterized in that the heating is carried out in the high-frequency field.