NO750399L - - Google Patents

Description

The invention relates to a method for producing stable dispersions of ethylene polymers, especially of polyethylene, in organic media, which consists of a non-solvent and . a solvent for the ethylene polymers, vinyl aromatics being used as solvent and unsaturated polyesters as non-solvents.

Low-waste curing unsaturated polyester resins

are gaining increasing importance due to their processing technical advantages. From German patent no. 1,241,983 it is known, for example, that molding compounds based on unsaturated polyester, to which a certain amount of ethylene polymers have been added, can harden crack- and blister-free. They also provide shaped bodies with a good surface. However, until now there has been a lack of a method according to which said ethylene polymers can be homogeneously distributed in a scale suitable for large-scale production in unsaturated polyester resins.

A uniform fine distribution is achieved without problems when the polymer is soluble in a polyester/vinyl aromatic system, as is the case, for example, with cellulose ester (compare US patent no. 3,642,672).

At room temperature, high-pressure polyethylene is neither soluble in volatile aromatics nor in unsaturated polyesters; at too high a temperature, it does dissolve in vinyl aromatics, but not in unsaturated polyesters or in a polyester/vinyl aromatic mixture. The direct use of granules, as it appears in the production of high-pressure polyethylene, therefore does not seem possible.

It is known to introduce powdered thermoplastics, such as polyethylene (French patent no. 1,148,285) or polypropylene (DOS 1,817,575, DAS I,192,820) into unsaturated polyester resins. However, the use of finely divided thermoplastic powders is not without problems due to the associated dust explosion hazard.

Furthermore, it is known to prepare polyethylene dispersions from granules in an aqueous dispersant-containing system (DOS 1,963,840). As thermoplastic additive for low-shrinkage curing polyester is

the obviously unsuitable aqueous dispersions.

Furthermore, it is known to produce polyethylene powder by dissolving granules in a mixture of solvents and non-solvents and subsequent distillation of the solvent.

(DAS 1,077,424, DOS 1,494,355 and 1,769,740). Stable polyethylene dispersions are admittedly not available in this way.

It is admittedly possible to homogenize a mixture of ethylene polymers and polyester resins, e.g. on a calender roll, however, this technique is not suitable for the production of filler-free, stable suspensions and therefore requires an immediate further processing into filled products, which are no longer flowable, such as e.g. for filled glass fiber reinforced resin mats. The possibility of temporal or spatial separation of resin production and processing into filler-containing masses is therefore not provided by this method.

Also, the combination of hot solutions of ethylene polymers on the one hand and polyesters on the other hand in vinyl aromatics does not bring the solution to the above-mentioned problems for gel-shaped precipitated ethylene polymers coagulate and form a clearly visible sedimented base. By stirring and adding dispersants, the 'coagulation' can be delayed, but not prevented.

It has now surprisingly been found that flowable stable dispersions of ethylene polymers can be produced in systems containing unsaturated polyesters and vinyl aromatics, by combining in the presence of dispersants the two solutions from ethylene polymers and unsaturated polyesters at elevated temperature in a zone of high turbulence, removes the formed mixture from this zone and keeps it under intense stirring at an elevated temperature until a low-viscosity, flowable state has formed.

For carrying out the procedure, it is advantageous

to carry out the union of the two solutions in a zone of high turbulence under the simultaneous influence of shear forces. On the other hand, it was found that during the post-stirring at an elevated temperature, shearing and cavitation forces should not be present or only be present in small amounts.

Zone of high turbulence within the framework of the invention generally means a room of intense mixing, through which it per.' hour

and per volume part. of the room' at least 300 volume parts liquid passes. Preferably there will be turbulence zones, where per hour and per volume part of the turbulence zone, the volume of liquid passed is 1,200 to 5,400 volume parts, i.e. where the residence time of the mixture in the turbulence zone is between approx. 6 seconds and less than 1 second.

For the production of a zone of high turbulence serves

one usually makes use of known devices, e.g. ordinary stirrers or better pumps equipped with rotors.

The specific mixing performance in an intensely stirred mixing vessel

-1-3-3

usually amounts to 10 to 10 watts/cm. It is immediately higher in the mixing thrombus and sufficient to form dispersions with an ethylene polymer content of up to 25% by weight. For example, a stirring vessel with disc stirrers and circuit breakers can be used, the ratio of boiler diameter: stirring diameter should be 1:0.9 to 1:0.2. When using such a mixing vessel, an appropriately separated feed can be achieved by filling one component (polyester/vinyl aromatic solution) immediately into the tube space and the other component (ethylene polymer/vinyl aromatic solution) into the stirrer's hollow shaft, so that both components are first mixed intensively and the vinyl aromatic content of the gel is only then reduced in another step at a lower stirring intensity and elevated temperature.

Pumps equipped with rotors are significantly better suited than conventional stirring vessels, above all because, with these, the residence time in the zone of high turbulence is greatly limited. A specific high-turbulence developed special design called a circular homogenization machine is suitable for particularly high performance, the specific mixing performance amounts to approx. 5 25 watts/cm^. They therefore enable particularly intense thorough mixing with very short residence times and are therefore preferably used.

It was found that, in order to achieve high suspension stability, it is particularly appropriate to recycle the mixture leaving the zone of high turbulence into the turbulence zone, so that the continuous newly added polyester and ethylene polymer solution in the zone of high turbulence is combined with already premixed product.

You can also mix the polyester solution with the recirculating mixture before entering the turbulence zone and allow the ethylene polymer solution into the turbulence zone. It is also possible to split a stream, e.g. of the ethylene polymer several sub-flows and allow these in different places of the turbulence zone. In order to run extremely high production performances, you can also connect several turbulence zones one after the other.

The dispersions produced by the method according to the invention can contain 25 to 60% by weight of unsaturated polyesters.

As a solvent both for the ethylene polymer and for the polyester, vinyl aromatics or mixtures of vinyl aromatics and polymerizable vinyl or divinyl compounds and allyl compounds are used.

The solids content of the dispersions produced by the method according to the invention is between 1 to 55% by weight, preferably between 5 to 25% by weight and in special cases between 11 to 17% by weight. Solids content means: Content of ethylene polymer and dispersant in % by weight. The ethylene polymer practically always dissolves in vinyl aromatics at an elevated temperature. The dispersant or the selected dispersant combinations are usually dissolved in the same way as the ethylene polymer in the vinyl aromatics, but may also be dissolved in the polyester or the polyester-vinyl aromatic solution or introduced later in the finished dispersion. The concentration of the two solutions to be combined by polyester on the one hand and ethylene polymer on the other is chosen so that the solutions are flowable and pumpable at the chosen working temperature. Admittedly, in principle, for example, the undiluted polyester can also be mixed with an ethylene polymer/vinyl aromatic solution in the manner mentioned; Of course, the polyester then had to be heated to a temperature of approx. 140 - 160°C to be well pumpable. However, since the ethylene polymer solution must also be heated to/at least 70°C in order to obtain a good solution, an excessively high mixing temperature occurred when the mass flow was combined and thus an undesired high degree of dissolution of the ethylene polymer in the system, so that such a process ^way not. leads to results.

The temperature at the joining of the two solutions

must be chosen so that on the<*> side it occurs in the first place . by the spontaneously starting precipitation of the ethylene polymer a gel and, on the other hand, the fastest possible migration of the vinyl aromatic from this gel into the polyester/vinyl aromatic phase is added during the stirring. "Elevated temperature" means a temperature of 50°C - 120°C, preferably

show between 60°Cbg 90°C. The end of the dispersing process is seen by the viscosity of the stirred system and, at the same time, the structural viscous properties, i.e. non-Newtonian conditions, decrease. When the viscosity does not change any more, the process can be stopped and the resulting dispersions of ethylene polymers in polyester/vinyl aromatic systems are stable.

It is surprising that this precaution of post-stirring at elevated temperature leads to the system with fine distribution and low viscosity. One should have expected that, on the contrary, rapid cooling and freezing cause the dispersed state of distribution once achieved with high energy to high stability of the suspension and at elevated temperature a reagglomeration occurs which in turn cancels the distribution once achieved.

The stability of the dispersions is significantly affected by the addition of dispersants.

Particularly effective dispersants are in polymerizable vinyl aromatics or in unsaturated polyesters or in a polyester/vinyl aromatic mixture soluble in high molecular weight polymers. Particularly preferred dispersants are ethylene-vinyl acetate copolymers or polyvinyl acetates, preferably those with 60 to 100% by weight, in special cases with 65 - 75% by weight vinyl acetate content and a 'Mooney viscosity of at least 15, preferably from 40 to 65 Mooney', measured according to DIN 53.523 (L-4).

Furthermore, however, poly-(meth)acrylic acid ester homo- and copolymers, which contain 1 to 2 4 C atoms in the alcohol component, are also suitable as dispersants, such as e.g. polyacrylic acid decyl ester or copolymers of ethylene with an ethylene content of up to 60% by weight (meth)acrylic acid esters, containing 1 to 24 C- atoms in the alcohol component or with vinyl esters of organic mono- or dicarboxylic acids with 1 to 19 C atoms or with their saponification products . Very good dispersants are also grafting polymers with the aforementioned polymers as grafting substrate.

Furthermore, suitable dispersants are polyethers, such as polyethylene oxide, polypropylene oxide and copolymers of these two compounds, ethoxylated saturated and unsaturated fatty acids, with 4 to 30, preferably with 6 to 19 C atoms, their esters containing 1 to 24 C atoms in the alcohol component, their amides and nitriles, fatty alcohols with 1 to 30, preferably with 4 to 16 C atoms or also graft polymers with these polymers as graft substrate,

as, for example, is mentioned in DAS 1,137,554.

Suitable grafting monomers are vinyl aromatics, such as vinyltoluene, α-methylstyrene, tert-butylstyrene, chlorostyrenes, preferably, however, unsubstituted styrene itself; vinyl acetate, (meth)-acrylic acid and their nitriles and esters, whose alcohol components may contain 1-18 C atoms, such as e.g. methyl methacrylate or ethyl acrylate, (meth)acrylonitrile, maleic anhydride, maleic acid half- and -diesters with 1-30, preferably 4 to 16 C atoms in the alcohol component. Of course it can as well as grafting substrate which. also grafting monomers also find application mixtures of the listed compounds.

Suitable dispersants are further cellulose derivatives such as methyl cellulose, ethyl hydroxy cellulose or cellulose esters, e.g. cellulose acetate, cellulose acetopropionate, cellulose acetob-utirate or nitrocellulose.

Often it is not possible to completely avoid the introduction of water during the production of the dispersion, if, for example, may be dissolved in the dispersant. Often, however, this is not a disadvantage; on the other hand, smaller amounts of water are purposefully added, as this precaution can improve the stability of the dispersion. The finished synthetic resin system can contain up to 5% by weight of water, but usually the water content is below 1% by weight.

The dispersants are added in a concentration of 0.001

to 20% by weight, preferably of 0.5 - 3% by weight, referred to the finished dispersion.

In order to preserve the polymerizable dispersion from unwanted premature polymerisation, it pays to add 0.001 - 0.1% by weight of polymerisation inhibitor or antioxidants to the dispersion already at the time of manufacture. Suitable aids of this type are, for example, phenol derivatives and phenols, preferably sterically hindered phenols, which in both o-positions of the phenolic hydroxy group contain alkyl substituents with 1-6 C atoms, amines, preferably secondary acrylamines and their derivatives, quinones, copper salts of organic acids, addition compounds of copper (I) halides to phosphites, such as e.g. 4,4'-bis-(2,6-di-tert-butylphenol), 1,3,5-trimethyl-2,4,6-tris-(3,5-di-tert-butyl1-4- hydroxy-benzyl)-benzene, 4,4'-butylidene-bis-(6-tert-butyl-m-cresol), 3,5-di-tert-butyl-4-hydroxy-benzyl-phosphonic acid diethyl ester, N, N'-bis-(g-naphthy1)-p-phenylene-diamine, N,N'-bis-(1-methylhepty1)-p-phenylenediamine, phenyl-8-naphthylamine, 4,4'-bis-(a, α-dimethylbenzy1)-diphenylamine, 1,3,5-tris-(3,5-di-tert.-butyl-4-hydroxy-hydrociunamoy1)- hexahydro-s-triazine, hydroquinone, p-benzoquinone, toluhydroquinone, p-tert.-butylpyrocatechin, chloranil, naphthoquinone, copper naphthenate, copper octoate, Cu(I)Cl/triphenylphosphite, Cu(I)Cl/trimethylphosphite, Cu(I)C1/trichloroethy1-phosphite, Cu(I)Cl/tri- propyl phosphite, p-nitrosodimethylaniline. Further suitable stabilizers are discussed in "Methoden der organischen Chemie" (Houben-Weyl), 4th edition, volume XIV/1, pages 433-52, 756, Georg Thieme Verlag, Stuttgart, 1961. Very suitable are f .ex. p-benzoquinone in a concentration from 0.01 to 0.05% by weight, referred to finished dispersion.

The ethylene polymers relevant for the dispersing method according to the invention are produced according to known pipe or stirred reactor methods. These are ethylene homopolymers and such ethylene copolymers, which contain comonomer amounts from 0.1 - 40% by weight, preferably 0.1 - 20% by weight, in special cases 3-12% by weight polymerized. α-olefins with 3-8 C atoms such as propylene, isobutene, butene-1 are used as comonomers. Furthermore, vinyl esters of organic carboxylic acids with 1 to 19 C atoms are also suitable, preferably vinyl acetate, vinyl halides such as vinyl chloride, (meth)acrylic acid, their esters,

which contain 1 to 8 C atoms in the alcohol component, their nitriles and amides, such as for example methyl methacrylate, ethyl acrylate, butyl acrylate, (meth)acrylonitrile, optionally substituted (meth)acrylamide.

The melt index values of the ethylene polymer measured according to DIN 53.735 at 190°C and 2.16 kp load lie in the range from not liquid to 1000; polyethylene types with melt index values between 0.1 and 20 are preferably used.

Of course, with the dispersion method according to the invention, not only high-pressure polyethylenes can be dispersed, but also polyethylene types produced according to the low-pressure or medium-pressure method, but also homopolyethylenes or ethylene copolymers produced according to special methods.

As vinyl aromatics, for the ethylene polymer seeds, e.g. the following solvents are used alone or in a mixture: Styrene, its core and side-chain substituted derivatives such as chlorostyrenes, vinyltoluene, divinylbenzene, α-methylstyrene, tert-butylstyrene, vinylpyridine, vinylnaphthalene, allylbenzene. Up to an amount of 80% by weight, these vinyl aromatics can be replaced without disadvantage with other polymerizable monomers, e.g. with vinylcyclohexane, (meth)acryl-

acid, their esters, amides and nitriles, maleic anhydride, -semi-

and -diesters, semi- and diamides or cyclic imides, such as N-methyl-maleinimide or N-cyclohexylmaleinimide, vinyl esters of organic carboxylic acids, such as e.g. vinyl acetate. It is also possible to use allyl compounds such as allyl acetate, diallyl isophthalate, allyl carbonates and diallyl carbonates.

The unsaturated polyesters used in the dispersion method according to the invention are produced according to known methods by polycondensation of at least one α,3-ethylenically unsaturated dicarboxylic acid or their ester-forming derivatives, optionally in admixture with up to 90 mol%, referred to unsaturated acid component of at least one saturated dicarboxylic acid or its ester-forming thereby-

spirit level with at least one dihydric alcohol. Examples for preferably usable unsaturated dicarboxylic acids or their derivatives are maleic acid or maleic anhydride and fumaric acid. However, mesaconic acid, citraconic acid, itaconic acid or chlormaleic acid can also be used. Examples of the saturated dicarboxylic acids used or their derivatives are phthalic acid or phthalic anhydride, isophthalic acid, terephthalic acid, hexa- or tetrahydrophthalic acid or their anhydrides, endomethylenetetrahydrophthalic acid and its anhydride, succinic acid resp. succinic anhydride and succinic acid esters and chlorides, adipic acid, sebacic acid. In order to be able to produce difficult flammable resins, it can e.g. hexachloroendomethylenetetrahydrophthalic acid (hot acid), tetrachlorophthalic acid or tetrabromophthalic acid are used. Flame resistance can also be achieved by adding halogen-containing compounds that are not condensed in the polyester, such as, for example, chlorinated paraffin. Preferably usable polyesters contain maleic acid, which up to 25 mol% can be replaced with phthalic acid or isophthalic acid. As dihydric alcohols, ethylene glycol, propanediol-1,2, propanediol-1, J>-diethylene glycol, dipropylene glycol, butanediol-1,3, butanediol-1,4, neopentyl glycol, hexanediol-1,6, perhydrobisphenol and second. Ethylene glycol, propanediol-1,2, diethylene glycol and dipropylene glycol are preferably used.

The preferably usable polyesters must have a high amount of polymerizable double bonds, as the mass according to the invention is pressed at high temperatures (140 - 160°C) and deformed and must therefore have a correspondingly high heat resistance.

The acid numbers of the polyesters used must lie between 1 and 50, preferably between 5 and 25, the OH numbers between 10 and 100, preferably between 20 and 50 and the molecular weights between approx. 500 and 10,000, preferably between approx. 700 and 3000.

Polymerizable, stable organic dispersions produced by the method according to the invention consist of 25-60% by weight of unsaturated polyesters, 1-35% by weight of ethylene polymers, 5-60% by weight of vinyl aromatics and 0.001-20% by weight of dispersants.

In the following, the method according to the invention will be explained with reference to two figures: Figure 1 shows a device for carrying out the method. In a mixing device 1, a polyester/vinyl aromatic solution is continuously filled from the heated storage vessel 2 via gear pump 3 and valve 4 and at the same time an ethylene polymer/vinyl aromatic solution from the heated storage vessel 5 via a gear pump 6 into the heat exchanger 7. In the mixing device 1 a highly structurally viscous gel arises from the vinylaromatic-containing flowable solution, the temperature of which, due to the introduced high mixing energy, is above the calculated mixing temperature. The gel leaves the mixing vessel via valve 8 and enters the heated mixing vessel

~9, whose free volume is several times the free mixing volume of the mixer. The stirring vessel 9 can of course also be designed as a heated pipe casing 10, so that the plant can be operated continuously with high production outputs.

in

Figure 2 shows a particularly advantageous applied variant of the method.

In a mixing vessel 1, a polyester/vinyl aromatic solution is continuously filled from the heated storage vessel 2 via gear pump 3 and valve 4 and at the same time an ethylene polymer/vinyl aromatic solution from the heated storage vessel 5 via a gear pump 6 and heat exchanger 7. the mixing device results from the liquid solutions containing vinyl aromatics a strong structurally viscous gel. This gel is recycled after leaving the mixing apparatus via heat exchanger 8 and a gear pump 9> which has approximately 10 times the pumping performance of pumps 3 and 6 via line 10 into the feed zone of the mixing apparatus via valve 11, so that to the mixing apparatus now three streams are supplied, two streams as shown in Figure 2 can be combined before the mixing zone. A partial flow of the product flow exiting via the pump 9 from the mixing zone is supplied via valve 12 to a heated mixing vessel 13. The mixing volume of this mixing vessel is again several times the mixing volume of the mixing zone.

After connecting the mixing vessel, it can be gradually cooled 15.

For further explanation, of the method, the preparation of a stable dispersion shall be mentioned, for example. of high-pressure polyethylene in a solution of an unsaturated polyester in styrene. Percentage indication in ne means percentage by weight. The polyester A used in the following examples is a condensation product of

31 wt$ propanediol-1,2,

17% by weight di-1,2-prqpandiol (= 4-oxa-heptatetraol-1,2,6,7),

40 wt% maleic anhydride,

12% by weight phthalic anhydride,

with an acid number of 30, which was produced by heating for 10 hours at 210°C. With the addition of 0.02 wt% of hydroquinone, the resulting polyester was dissolved in styrene to a 65 wt% solution with a dynamic viscosity of 1500 cP, measured according to DIN 53.015 at 20°C,

• (= polyester solution A).

As polyethylene B, a high-pressure homopolyethylene with a melt index of 6.1, measured according to DIN 53-735a as ethylene-vinyl acetate copolymer C, a high-pressure polyethylene with a vinyl acetate content of 8.5% by weight and a melt index of 5.15 measured was used according to DIN 53-735.

Example 1.

Procedure according to figure i.

188 kg per hour of polyester solution A was according to

fig. 1 the capacity of the mixer with 134 kg per hour of a 28.6% solution of polyethylene B in styrene, which contained 4.85% by weight of eb. ethylene-vinyl acetate copolymer with 70% by weight vinyl acetate content and a Mooney value of 50, measured according to DIN 53-523 (L-4). The temperature of d-e two solutions before entering the mixing apparatus which operated with a mixing power of 25 watts/cm^ was 78°C.

After leaving the mixing zone above valve 7, the temperature of the mixed product is 88°C. The product's temperature is raised in the heated mixing vessel from 8 to 90°C. After the mixing vessel has been filled, stir for another 45 minutes. The product can e.g. is cooled while stirring, as the stirring vessel's heating is switched off, however, it can also be filled in a warm state and added for further use or for storage. A connected stirring boiler cascade is often appropriate for a continuous production process. Only the condition of the one in this example approx. must be observed. 45 minutes with subsequent stirring at 90°C. A suspension is obtained with a dynamic viscosity of 792 cP (25°C), measured according to DIN 53.015. Oak sample 2.

Procedure according to Figure 2.

80 kg per hour of polyester solution A is supplied with 53j5kg per of a 31.2% solution of ethylene-vinyl acetate copolymer C in styrene, which further contains 1.25% by weight of a ethylene-vinyl acetate copolymer with 75 wt.^ incorporated, vinyl acetate (Mooney value 54, measured according to DIN 53-523, L-4), according to figure 2 for the mixing apparatus, which works with a mixing power of 20 watts per cm^. The temperature of the ethylene-vinyl acetate copolymer solution is 80°C, the temperature of the polyester solution is 20°C. Above pump 12, 1.2 m^ per hour as internal circuit; the temperature of this internal circuit is maintained above heat exchanger 8, which in this example is cooled by the sun at -10°C, at 80°C. Then in relation to the work according to figure 1 in this production method according to figure 2 the amount of product newly added to the mixing zone per hour is significantly reduced, the mixing energy added to the product and thus also the temperature increase of the product is of course significantly higher in the mixing zone. For this, via pump 11 maintained internal circuit runs are withdrawn via valve 12, 120 liters per hour mixing product, - is added to the heated mixing vessel 13, in which the product is heated to 90°C and stirred for 15 minutes at this temperature. A suspension is obtained with a dynamic viscosity of 680 cP (25°C), measured according to DIN 53.015.

Example 3.

Procedure according to Figure 2.

80 kg per hour of polyester solution A is added with

54 kg per hour of a 28% solution of ethylene-vinyl acetate copolymer C in styrene, which further contains 2.7 wt$ of an ethylene-vinyl acetate copolymer with 70 wt$ incorporated vinyl acetate (Mooney viscosity: 50 - 52 Mooney, measured according to DIN 53.523, L-4), according to Figure 2 to the mixing apparatus, which works with a mixing performance of 25 watts/cm-^. The temperature of the ethylene polymer solution is 80°C, the polyester solution 25°C. Above pump 12, 1.2 m^ per hour. as internal circuit; the temperature of this

internal circuits are kept at 80°C above heat exchanger 8, which in this example is cooled with a brine of -10°C. From the internal circuit, 12,120 liters per hour mixing product and added to the heated mixing vessel 13, in which the product is stirred for 30 minutes

at 65°C and 30 minutes at 50°C. During this time, 1% by weight of a grafting product of styrene and polyethylene oxide is dissolved in the suspension and 0.3% by weight of water is also added to prepare the dispersant: In 1 kg of polyethylene oxide of a molecular weight of approx. 1500 are dripped in at 160 - 176°C over the course of 2 hours 1600 g of styrene containing dissolved 16 g of benzoyl peroxide. After instillation, stir for 3 hours at 170°C and 4 hours at 180°C, then cool. You get a suspension with a dynamic viscosity of 750 cP, measured according to DIN 53.015. Oak sample 4.

Using a dispersion produced by the method according to example 1: Following the following recipe, a dark brown colored resin mat was produced: .....

Dispersion 100 parts by weight

containing 12 parts by weight of high-pressure polyethylene B

2.0 parts by weight of an ethylene-vinyl acetate copolymer with 70% by weight of vinyl acetate (Mooney viscosity: 52 Mooney, measured according to DIN 53.523 (L-4)

28 parts by weight of styrene

60 parts by weight polyester solution A Filler calcium carbonate, ("Durcal" 5 from Omya): 100 parts by weight Zinc stearate 4 parts by weight tert-butyl perbenzoate, 95#-ig 0.75 parts by weight Iron oxide red Bayer 130 B 3.35 parts by weight Iron oxide black Bayer F 318 1.65 parts by weight Magnesium oxide ("Marmag" from

Merck, Darmstadt) 1.5.0 parts by weight p-benzoquinone 0.01 parts by weight.

A glass silk mat ("Vetrotex" M 612) was impregnated with the mixture, the finished resin mat having a glass content of 26-28%. The resin mass was subjected to maturation at 25°C for 7 days. It then had a dry surface, the polyethylene foil was easily removed.

From this resin mat, tablets and "rib and nub plates" were produced in metal tools at 140°C. The pressing pressure was 30 kp/cm 2 for the tablet, 150 kp/cm 2 for the rib and nub plate. The pressed parts of the resin mat had a medium gloss surface

and had barely visible points of incidence on material thickenings.

It was homogeneously colored dark brown. The linear shrinkage amounted to 0.05$ and on the surface of the molded part a weakly pronounced glass fiber structure could be seen.

E xample 5-, 1

Following the recipe given in Example 4, a resin mass was produced from a dispersion according to Example 2. The dispersant content (ethylene-vinyl acetate copolymer with 70% by weight of vinyl acetate) amounted to 0.5 parts by weight per 100 parts by weight of dispersion.

After 7 days of maturation at 25°C, the polyethylene foil was easily removed from the dry surface of the resin mat. As indicated in example 4, tablets and ribbed and nub plates were pressed. The pressed parts had a high-gloss, homogeneous dark brown colored surface without any glass fiber structure and have no points of incidence on material thickenings. The linear loss was less than 0.01$.

Oak sample 6.

Following the recipe given in example 4, a resin mat was produced from a dispersion according to example 3 - The dispersant content in the dispersion was 1.1% by weight of an ethylery-vinyl acetate copolymer with 70% by weight incorporated vinyl acetate and Mooney viscosity 52, measured according to DIN 53-523, L-4 and 1 weight?" of a grafting product of styrene on polyethylene oxide with approx. 67% by weight styrene content. After 7 days of maturation at 25°C, the polyethylene foil was easily pulled off the dry surface of the resin mat. As indicated in example 4, pressed parts were produced. The finished molded parts were homogenously colored dark brown and had a high-gloss surface with no visible glass fiber structure and have no points of entry on material thickenings. The linear loss was less than 0.01$.

Claims (3)

1. Process for producing flowable, stable dispersions of ethylene polymers in systems containing unsaturated polyesters and vinyl aromatics, characterized by combining the heated to 50 - 120°C solutions of ethylene polymers and the unsaturated polyesters in vinyl aromatics in the presence of dispersants in a zone of high turbulence, remove the resulting mixture from this zone and stir vigorously at elevated temperature until a low-viscosity, flowable state has formed. 2. Method according to claim 1, characterized in that polyvinyl acetates or §i^l§^¥iif^låQetat=Hopolymerisates are used as dispersants with a vir#lå8ejSalifififc6±å of 60 100 weight# and a Mooney viscosity of at least 15 Mooney. . 3. Polymerizable stable dispersions, produced according to the method according to claim 1.