DE1945474A1 - Use of polymeric isocyanates as active fillers in plastics - Google Patents

Description

FARBENFABRIKEN BAYER AG

LEVERKUSEN-Bayennifc V / r / Tr Fucot-AbttUaas

- 8th SEP. 1969

Use of polymeric isocyanates as active fillers in plastics

The polymerization of polyisocyanates into even further convertible soluble partial polymers with an isocyanurate content, which corresponds to the conversion of Ms to 50% of the isocyanate groups originally present, through a defined process Polymerization is known from many publications.

These processes require a very defined reaction procedure, since polymers obtained from polyfunctional isocyanates generally have a degree of polymerization corresponding to 50 % of the isocyanate groups shortly after crossing the reaction . the formation of higher molecular weight and more highly branched products become insoluble in the usual solvents. A further difficulty is that such a defined polymerization of the NCO groups takes place with most catalyst systems after an incubation period has passed.

A more extensive polymerization (ie over 50 μs degree of polymerization) generally leads to compact and un-

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Soluble masses which, due to the exothermic heat of the polymerization, often show strong discoloration and nuclear burn phenomena in larger batches. So far, such masses could not be made accessible for any further use.

In addition to these processes leading to compact masses, various possibilities have recently become known of polymerizing polyisocyanates with special catalysts, blowing agents and optionally H-acidic compounds in a one-step process to obtain foams whose structural units are largely composed of isocyanurate ringin see also "Polyurethanes, Chemistry and Technology", Ed. I and II, Saunders-Frisch, Interscience Publishers 1962, p. 94.

Furthermore, methods have become known through the use of special, Phosphorus-containing catalysts convert polyisocyanates into polycarbodiimides, but are also used in this

the

Case due to / polymerisation tendency of the carbodiimide groups more or less branched products are obtained, so that the disadvantages listed above also occur for these polymeric isocyanates.

A production of compact solids with a higher isocyanurate content However, it was practically impossible to achieve in a defined and reproducible manner.

As will be shown below, however, through a suitable selection of the starting components, catalysts and heating conditions, it is possible to obtain such compact solids with a higher isocyanurate content by reacting at least 60% of the isocyanate groups originally present in the organic polyisocyanates used. Such compounds are referred to below as polymeric isocyanates, with polymerization essentially being understood to mean the formation of isocyanurate rings and / or a condensation to form an oxymide structure, which takes place with an OOp atomic gap. As

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It has now been shown that such polyisocyanates can be very advantageous can be combined with other plastics as filler and blending components.

The present invention therefore relates to the use of organic isocyanate polymers which are obtained by reaction of at least 60% by weight in organic isocyanates originally existing isocyanate groups with themselves with formation have been obtained from carbodiimide and isocyanurate groups, as fillers in plastics.

The polyisocyanates used for the preparation of the polymeric isocyanates are aliphatic and preferably aromatic polyvalent ones Isocyanates in question, e.g. alkylene diisocyanates such as tetra- and hexamethylene diisocyanate, arylene diisocyanates and their alkylation products such as phenylene diisocyanates, naphthylene diisocyanates, diphenylmethane diisocyanates, tolylene diisocyanates, di- and triisopropylbenzene diisocyanate and triphenylmethane triisocyanate, Tri- (p-isocyanatophenyl) thiophosphate, tri- (p-isocyanatophenyl) phosphate, Aralkyl diisocyanates such as l- (isocyanatophenyl) ethyl isocyanate or the xylylene diisocyanates. As special 2,4- and 2,6-tolylene diisocyanate in particular have proven suitable and any mixtures consisting thereof, as well as that produced by phosgenation of the aniline-formaldehyde condensation product obtained polyphenylene-polymethylene-polyisocyanate mixture. Furthermore, those with a wide variety of substituents are suitable such as alkoxy, nitro, chlorine or bromine-substituted polyisocyanates, and also with insufficient amounts of polyhydroxy ! Compounds such as trimethylolpropane, hexanetriol, glycerine, butanediol modified polyisocyanates. The polyisocyanates which can be prepared according to Belgian patent specification 714 850. Examples include phenols and oximes or bisulfite-capped polyisocyanates, acetal-modified isocyanates and partially polymerized isocyanates with isocyanurate rings, and also higher molecular weight polyisocyanates, which by

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Implementation of monomeric polyisocyanates with nJ * uer- and / or higher molecular weight compounds with reactive hydrogen atoms, preferably low and / or high molecular weight polyhydroxy ! connections that can be produced. It can of course Mixtures of different isocyanates can also be used, monoisocyanate also being used in this case

Catalysts for the production of polymerized isocyanates are known in large numbers. For example, in Erage the salts of alcohols, phenols or carboxylic acids on the one hand and alkali and alkaline earth metals on the other hand, tert. Amines, optionally in combination with cocatalysts such as epoxides or hydroxymethylphenols etc., as they are found in large numbers, e.g. in Polyurethanes, Chemistry and Technology, Vol. I and II, Saunders-Frisch, Interscience Publishers 1962, p. 94; Plastics Handbook, Vol. VII, Vieweg-Höchtlen, Hanser-Verlag 1966, German patents 954 376, 1 112 285, British patent 1 104 394 or Belgian patents 680 380, 697 411, 723 152 and 723 153 are described.

In order to achieve a defined polymerization, it is advisable to use catalysts that are as uniform as possible Polymerization of the isocyanate groups in a manner and without incubation time cause. For example, solutions of the alkali alcoholates and phenolates in polar ones are particularly suitable for this purpose Solvents with dimethylformamide or N-methylpyrrolidone, Combinations of N, K "', N" -Tris- (dimethylamino-propy3) -hexahydrotriazine and epoxides or the Mannich bases listed in Belgian patents 723 152 and 723 153. These catalysts which are generally used in amounts between 0.1 and 10, preferably between 1 and 5 wt .- $, start the polymerization in a defined manner and lead to a more or less brittle, easily crushable polymer,

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the 3 ^e , depending on the amount of catalyst used, contains more or less high proportions of free isocyanate groups, for example between 5 and 40 56 of the isocyanate groups originally present. To simplify the processing and the polymerization reaction, the polymerization can also, or preferably, take place in the presence of blowing agents, which lead to a slightly puffed and easily grindable material. The carbon dioxide split off during carbodiimide formation and also additional blowing agents from the class of halogenated hydrocarbons can be used as blowing agents.

The catalysts listed above lead in addition to a trimerization reaction already to the formation of more or less high proportions of garbodiimide structures, which / as already stated / ait a certain propellant effect is connected; this driving effect can be achieved through the use of special compounds that catalyze the formation of carbodiimide groups such as phosphorus compounds (phosphines, phospholines, phospholine oxides, / cyclic / esters, amides, ester amides of phosphorous and phosphoric acid).

The production of the polymers can be carried out batchwise in small batches take place, but must generally be carried out in a continuous manner due to the heat of reaction to be removed be carried out by using isocyanates and catalysts by machine, as was already the case with polyurethane foam production known, are mixed and the mixture is introduced into appropriate generally open vessels.

In addition to the components mentioned, compounds with one or more reactive hydrogen atoms can be added to a lesser extent, ie up to about 25 mol / l, based on the isocyanate groups present, for example

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wise mono- or polyalcohols, mono- "or polyamines or mono- or polycarboxylic acids, as they are known from polyurethane chemistry". Further, the polymerization in the presence of inactive I ¹ UlIstoffen, pigments, flame retardants can !! (Antimony, phosphorus or halogen compounds) etc. made and these are incorporated or included in the polymer. With regard to the H-acidic compounds to be used, reference is made to "Polyurethanes, Chemistry and Technology", Vol. I and II ,. Saunders-Frisch, Interseience Publishers, 1962 and Eunststoffhandbuch, Vol. VII, Vieweg-Höchtlen, Hanser-Verlag, 1966 referenced.

The isocyanate polymers obtained in this way generally have isocyanurate and carbodiimide structures; in addition, however, there may also be carbodiimide subsequent structures, which are due to a polymerization or a partial reaction of the carbodiimide groups formed with isocyanate groups. For steric reasons alone , complete polymerization of the JfCO groups is not achieved, so that the products still have different proportions of isocyanate groups, depending on the type and amount of catalyst.

The isocyanate polymers obtained in this way generally have Isocyanurate, carbodiimide and their subsequent structures.

After the polymerization, the reaction products are comminuted and in this form as a mixing component with a wide variety of, preferably with, isocyanate groups reactive hydrogen 'containing plastics. Here can

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Depending on the type of plastics used, a reaction and thus additional crosslinking or binding of the filler to the polymer take place via the functional groups present in the polymers. There are no limits to the amount of filler to be used. Generally between 10 and 90 #, based on the finished mixture, are used. In principle, the most diverse types of plastics can be used. Particularly to be considered are, for example, condensates formed from phenols, ureas, melamine and similar amides with aldehydes, polycondensates such as polyesters, polycarbonates or polysulfones, but also olefin polymers such as polyethylene, polypropylene, polystyrene, the corresponding copolymers such as acrylonitrile-styrene , Butadiene-styrene, acrylonitrile-butadiene-styrene copolymers, polyacrylates, polyvinyl acetates and corresponding copolymers and also polyaddition compounds such as, for example, polyurethanes .

The advantages of the polymers used as the filler for the said plastic materials are their high thermal stability as well as in their Hamm chiitzeigeDSChaften. It can be assumed that the isocyanate polymers will ultimately be exposed to! Temperature exposure below G0 _? - Splitting and swelling of largely aromatic polycarbodiimide structures are formed, which protect the lower layers from further attack by heat and open flame.

Further details of the invention emerge from the following Examples.

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Examples:

Examples 1 to 3 describe the preparation of isocyanate polymers to be used according to the invention.

Examples 4 and 5 describe the use according to the invention of isocyanate polymer prepared according to Example 1 as Filler.

Example_2

^{600 g of catalyst A +} ^ are quickly stirred into 10 kg of polyphenylene-polymethylene-polyisocyanate mixture, produced by phosgenation of aniline-I-malaldehyde condensation product. The polymerization starts immediately with development of heat. After cooling, the brittle mass is ground to a fine powder.

IR spectrum;

Isocyanurate band: 1410 cm "

Isocyanurate-carbonyl band: 1710 cm ~

Isocyanate band: 2260 cm ""

Catalyst A used in Example 1 is the Mannich base listed in Belgian patents 723 152 and 723 153, which was prepared as follows: To a mixture of 376 parts by weight of phenol and 1440 parts by weight of dimethylamine solution (25%) are added 30 ° over one hour parts by weight of formaldehyde solution (25 #ig) was added dropwise. Then 1 hour at 30 ° and a further 2 hours at 80 ° is kept, after the addition of sodium chloride the organic phase separated and evaporated these mm at 9O ⁰ C / 12 Hg.
cP _£ : 2500; Amine equivalent: 105

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60 parts by weight of catalyst A are quickly stirred into 1000 parts by weight of 4 »4 ^{t -diisoeyanato-diphenylmethane at room temperature.} The mixture warms up immediately and solidifies after a few minutes with slight puffing to a brittle mass. The residual isocyanate content corresponds to 34 # of the isocyanate groups originally contained in 4,4'-diisocyanatodiphenylmethane.

IR spectrum;

Isocyanurate band: 1410 cm "

Isocyanurate-carbonyl band: 1710 cm

Isocyanate band: 2260 cm ~

60 parts by weight of catalyst A are quickly stirred into 1000 parts by weight of 2,4-diisocyanatotoluene at room temperature. The reaction proceeds as described in Example 8. The rest isocyanate content equivalent to 35 $> the HOO groups originally contained in 2,4-diisocyanatotoluene.

IR spectrum;

Isocyanurate band: 1410 cm "

Isocyanurate carbonyl band: 1710 cm "

Isocyanate band: 2260 cm

20 wt .- # of Isocyanatpolymerisats prepared according to Example 1 are added to a rolling mill of an acrylonitrile-butadiene-styrene-copolymer composed of 25 f> acrylonitrile, 15 $> butadiene and 60 $> styrene. The roller temperature in this case is 16O ⁰ C, the Einwalzzeit for 15 minutes, the rolling time of Pelle 5 minutes. Press plates were made from the rolled sheets.

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A comparison of the flame behavior of the press plates produced in this way with the flame behavior of press plates made of unfilled ABS copolymer shows the excellent flame retardancy Effect of the fillers to be used according to the invention. The unfilled press plates can be easily ignited by a flame and burn at the same time Melt. The filled press plates are self-releasing and only show signs of charring when exposed to a flame.

A similar flame behavior is shown by ABS press plates filled with isocyanate polymers prepared according to Example 2 and.

BeispJLel_5 .:

300 parts by weight of a phenolic resin, prepared from 470 parts by weight of phenol, 900 parts by weight of 30 parts by weight of aqueous formaldehyde solution and 55 parts by weight of 24 parts by weight of aqueous ammonia solution were mixed with 200 parts by weight of the substance according to Example 1 - isocyanate polymer produced mixed. The mixture was processed into plates at up to 180 ^° C. and 100 atm pressure. While the mechanical values of those made from pure phenolic resin are comparable to those made from filled phenolic resin, there are significant differences in the fire behavior. The panels made from filled phenolic resin char to a porous black mass when exposed to a flame. The press plates made of pure phenolic resin can be ignited by a flame and burn while melting at the same time.

Phend resin test specimens show a corresponding flame behavior, Weihe are filled with comparable amounts of isocyanate polymers prepared according to Example 2 and 3 ■.

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Claims (8)

Patent claims: 1. Use of organic ». Isocyanate polymers which have been obtained by reaction of at least 60% of isocyanate groups originally present in organic isocyanates with themselves with the formation of carbodiimide and isocyanurate groups , as fillers in plastics. 2. Use of organic isocyanate polymers according to Claim 1 as fillers in acrylonitrile-butadiene-styrene copolymers. 3. Use of organic isocyanate polymers according to Claim 1 as fillers in phenolic resins. 4. Use of organic isocyanate polymers according to Claim 1 as fillers in urea-formaldehyde resins. 5. Use of organic isocyanate polymers according to claim 1 as fillers in polyurethanes. 6. Use of organic isocyanate polymers according to Claim 1 as fillers in polyester resins. 7. Use of organic isocyanate polymers according to Claim 1 as fillers in natural or synthetic rubber. 8. Use of organic isocyanate polymers according to claim 1 as fillers in active hydrogen atoms cmden plastics. Le A 12 092 - 11 - 109817/1988