DE2625027A1 - Free radical catalysts, esp. for unsatd. polyesters - are prepd. by reacting a metal alkyl or aryl, a diaryl ketone and water, an acid halide, an anhydride or a silane - Google Patents

Abstract

Initiators for free radical polymerisation reactions comprise reaction mixtures obtd. by reacting (1) metal alkyls, -aryl or -aralkyls, R1R2R3CM (in which M is Na, Li, MgCl, or MgBr; R1 and R2 are H, 1-4C alkyl, phenyl or benzyl, and R3 is 1-4C alkyl or phenyl) with (2) diaryl ketones (in which R4 and R5 are H, Cl, F, 1-4C alkyl, OMe, phenyl or benzyl) and reacting the prod. with (a) water, (b) and halides R6-COX (where X is Cl or Br; and R6 is 1-4C alkyl, phenyl or benzyl) (c) acid anhydrides R7-CO-O-CO-R8 (in which R7 and R8 are 1-4C alkyl or phenyl), or (d) silanes R9R10R11SiY (in which R9 is Me, Et or phenyl; R10 and R11 are Cl, Br, 1-4C alkyl, phenyl or 1-3C alkoxy; and Y is Cl or Br). The initiator compsn. have good storage stability at room temp. but are more reactive than known peroxide catalysts at elevated temps. They are harmless and present no dangers on handling. They can be used in very low concn. to give rapid cures, e.g. at temps. of >40 degrees C. The initiator systems are esp. useful as curing agents for unsatd. polyester resins and for polymerising monomers such as styrene, (meth)acrylic esters etc.

Description

Use of reaction mixtures as polymerization

initiators The present invention relates to the use of Reaction mixtures obtained by reacting metal alkyls, aryls or aralkylenes with diaryl ketones and subsequent reaction with water, acid halides, acid anhydrides, Alkyl or arylchlorosilanes are available as initiators for radical initiators Polymerization reactions.

From DT-AS 1 216 877 and 1 219 224 as well as from DT-OS 2 131 623 and 2,164,482 it is known that 1.1.2.2-tetraaryl-1.2-dihydroxyethanes, their Alkyl and silyl ethers as initiators for radical polymerization reactions suitable. In contrast to the known peroxide catalysts, they are completely safe to handle. The hardening of radical polymerizable substances in the presence these initiators can be easily and safely controlled by temperature control.

The object of the present invention was to provide substances which are suitable as initiators for radical polymerization reactions, with your initiating However, this does not affect the ability to react should be based on the peroxide grouping. The desired substances should also have a good storage stability at room temperature in the polymerizable systems, at increased Temperatures but the already known peroxide-free initiators with regard to their Reactivity at the lowest possible concentrations in the polymerizable system still surpass.

Surprisingly, it has now been found that the reaction of metal alkyls, -arylene or -aralkylene, preferably of lithium, sodium or magnesium compounds, with diaryl ketones and the subsequent reaction with water, acid halides, acid anhydrides, Alkyl or aryl chlorosilanes lead to reaction mixtures that are already low in Concentrations partly a quick and complete one at temperatures from 400 C upwards Cure through hardening of the substances to be polymerized. Also stand out polymerizable systems with a content of those to be used according to the invention initiating reaction mixtures are characterized by a relatively high storage stability.

The invention relates to the use of reaction mixtures obtained by reacting (1) metal alkyls, aryls or aralkylenes of the formula wherein M is Na, Li, MgCl, MgBr or MgBr, R1 and R2 are a hydrogen atom, an alkyl radical with 1 - 4 carbon atoms, a phenyl or benzyl radical and R3 is an alkyl radical with 1 - 4 carbon atoms or a phenyl radical, with (2) diaryl ketones of the formula wherein R4 and R5 denote a hydrogen, chlorine or fluorine atom, an alkyl radical having 1-4 carbon atoms, methoxy, a phenyl or benzyl radical, and (3) subsequent reaction with (a) water, (b) acid halides of the formula in which X is a chlorine or bromine atom and R6 is an alkyl radical with 1-4 C atoms, a phenyl or benzyl radical, (c) acid anhydrides of the formula in which R7 and R8 denote an alkyl radical having 1-4 carbon atoms or a phenyl radical, or (d) silanes of the formula in which Y denotes a chlorine or bromine atom, R9 denotes methyl, ethyl, phenyl, R10 and R11 denote a chlorine or bromine atom, an alkyl group with 1 to 4 carbon atoms, a phenyl group or an alkoxy group with 1 to 3 carbon atoms The reaction mixtures to be used as initiators according to the invention can generally be prepared according to the following instructions: A solution of 1.0 mol of diaryl ketone (2) in an inert solvent is added at a temperature of -20 to + 35, preferably 0 to 10 ° C, the solution of 0.9-1.1 mol, preferably 1.0-1.1 mol, normally approx.

equimolar amounts of the organometallic compound (1) in an inert Dissolving agent dripped. It is left for 0.2-3 hours at -20 to +350 ° C., preferably at room temperature, stir and then give at least 1 to 1.2 mol - in the case of Water about 500 ml - of the compound (3). After stirring for several hours (1 - 10 hours) 1.5 liters of water are added at room temperature organic Phase separated and the solvent removed. The reaction mixture thus obtained can be used as an initiator without further purification.

It is sometimes advisable to use the organometallic compound (1) in higher concentration than to be used in an equimolar ratio, since under the reaction conditions partial decomposition is possible. If that to be used according to the invention Reaction mixture should have low reactivity, based on decomposition of the compounds active as initiators can be traced back during production, it is advisable to lower the reaction temperature.

For the preparation of the reaction mixture to be used according to the invention suitable inert solvents are ethers such as dibutyl ether, anisole, tetrahydrofuran, preferably diethyl ether; but also in tertiary amines, such as. B.

Triethylamine, in hydrocarbons, such as. B. pentane, or in phosphoric acid tris (dimethylamide), the reaction can be carried out (see also methods of organic chemistry (Houben-Weyl), Vol. XIII / 2a, pp. 59-70, Georg Thieme-Verlag, Stuttgart 1973).

As examples of reaction mixtures to be used according to the invention the products of the following reactions may be mentioned: a) Mg-tert.-butyl chloride + benzophenone + Water b) Li-tert-butyl + benzophenone + water c) Mg- (o-chlorobenzyl) chloride + Benzophenone + water d) Mg-isopropyl bromide + benzophenone + water e) Mg-isopropyl bromide + o-chlorobenzophenone + water f) Mg-isopropyl bromide + 4,4'-dimethylbenzophenone + Water g) Na-tert-butyl + benzophenone + phenylacetic acid chloride h) Mg-tert-butyl chloride + Benzophenone + acetic anhydride i) Mg- (o-chlorobenzyl) chloride + benzophenone + benzoyl chloride k) Li-tert-butyl + benzophenone + trimethylchlorosilane 1) Mg-isopropyl bromide + benzophenone + Trimethylchlorosilane m) Li- (o-chlorobenzyl) + benzophenone + trimethylchlorosilane n) Mg- (o-chlorobenzyl) chloride + benzophenone + methylethoxydichlorosilane o) Mg-isopropyl bromide + Benzophenone + diphenyldichlorosilane p) Li-isopropyl + benzophenone + dimethyldichlorosilane q) Mg-L-methylbenzyl) chloride + benzophenone + dimethyldichlorosilane Reaction mixtures to be used are characterized by an extraordinarily high level Reactivity off. So they surpass those due to the manufacturing process as Benzpinacol derivatives suspected to be the main constituent in terms of their reactivity considerably, so that it is believed that the reaction mixtures are either extremely reactive Components contain or that the reactivity can be attributed to a synergism is.

The reaction mixtures to be used as initiators according to the invention are in some cases already effective at temperatures above 400 C. A complete and will harden quickly usually when 0.05 is used - 2, preferably 0.1-1,% by weight, based on the substance to be polymerized, achieved.

The start of the polymerization reaction is made by heating a mixture of substance to be polymerized and reaction mixture to be used according to the invention via a specific light-off temperature that can be easily determined in individual cases.

The hardening can be carried out in one go, but also in stages if desired, take place (see GB-PS 1 041 614).

It is possible to set the light-off temperature by means of a simple color reaction determine the initiator reaction mixtures to be used according to the invention: The radicals formed during thermal decomposition can namely be quinoid Decolorize dyes. To carry out the test, a small amount of quinoid is dissolved Dye, e.g. B. methylene blue, thiomin or neutral red in a solvent, which is free of molecular oxygen, e.g. B. glycol, xylene, and sets at least one equivalent amount of the reaction mixture to be used according to the invention. the The temperature at which the dye is decolorized is the light-off temperature Initiator reaction mixture.

As substances whose polymerization by the invention to can be initiated using reaction mixtures, all radically polymerizable come Compounds or mixtures into consideration, e.g. B. So conjugated dienes such as butadiene, Isoprene, chloroprene; Vinyl chloride, vinylidene chloride; aromatic Vinyl compounds such as styrene, divinylbenzene; Vinyl esters, especially vinyl acetate and vinyl propionate; Vinyl ethers such as vinyl propyl ether, vinyl isobutyl ether; Acrylic acid and methacrylic acid and its derivatives such as esters, especially with aliphatic Alcohols with 1 to 5 carbon atoms, nitriles, amides, etc .; Di (vinylphenyl) carbonates; Diallyl phthalate, Diallyl carbonate, diallyl fumarate; Di (allylphenyl) carbonates; Polyol poly (meth) acrylates; N.N'-methylenebis (meth) acrylamide.

Particularly suitable substances for initiating polymerization with the reaction mixtures to be used according to the invention are unsaturated polyester resins, d. H. the solutions whether d, ß-ethylenically unsaturated polyester in copolymerizable therewith Monomers.

Suitable, ß-ethylenically unsaturated polyesters are the customary polycondensation products at least one ßäthylenisch unsaturated dicarboxylic acid with usually 4 or 5 carbon atoms or their ester-forming derivatives, e.g. B.

based on their anhydrides, possibly in a mixture of up to 200 mol% on the unsaturated acid components, at least one aliphatic saturated with 4 - 10 carbon atoms or a cycloaliphatic dicarboxylic acid with 8 - 10 carbon atoms or their ester-forming derivatives with at least one polyhydroxy compound, in particular Dihydroxy compound with 2-8 carbon atoms - i.e. polyester, as described by J. Björksten et al., "Polyesters and their Applications", Reinhold Publishing Corp., New York 1956.

Examples of unsaturated dicarboxylic acids to be used with preference or their derivatives are maleic acid or maleic anhydride and Fumaric acid. Can be used, for. B. but also mesaconic acid, citraconic acid, Itaconic acid or chloromaleic acid. Examples of the aliphatic to be used Saturated and cyclo-aliphatic dicarboxylic acids or their derivatives are phthalic acid or phthalic anhydride, isophthalic acid, terephthalic acid, hexa- or tetrahydrophthalic acid or their anhydrides, endomethylenetetrahydrophthalic acid or their anhydride, succinic acid or succinic anhydride and succinic acid esters and chlorides, adipic acid, Sebacic acid. To produce flame retardant resins, z. B. Hexachlorendomethylenetetrahydrophthalic acid (Hetsäure), tetrachlorophthalic acid or tetrabromophthalic acid can be used. as Dihydric alcohols can include ethyl glycol, 1,2-propanediol, 1,3-propanediol, diethylene glycol, Diproylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 2,2-bis (4-hydroxycyclohexyl) propane, bis-oxalkylated bisphenol A, perhydrobisphenol and others are used. Ethylene glycol, 1,2-propanediol, Diethylene glycol and dipropylene glycol.

Further modifications are possible by incorporating single, trivalent and tetravalent units Alcohols with 1 - 6 0 atoms, such as methanol, ethanol, butanol, allyl alcohol, benzyl alcohol, Cyclohexanol and tetrahydrofurfuryl alcohol, trimethylpropane, glycerine and pentaerythritol as well as of mono-, di- and triallyl ethers and benzyl ethers trivalent and polyvalent Alcohols with 3 - 6 carbon atoms according to DT-AS 1 024 654, as well as through the incorporation of monobasic Acids such as benzoic acid, or long-chain unsaturated fatty acids such as oleic acid, Linseed oil fatty acid and ricine fatty acid.

The acid numbers of the polyesters are usually between 1 and 100, preferably between 20 and 70, the OH numbers between 10 and 150, preferably between 20 and 100, and the molecular weights determined as number average M between n approx. 500 and 5000, preferably between approx. 1000 and 3000 (vapor pressure osmometric measured in dioxane and acetone; if the values differ, the lower than the correct one).

As with the unsaturated polyesters copolymerizable vinyl and Vinylidene compounds are suitable unsaturated ones commonly used in polyester technology Compounds which are preferably #, -substituted vinyl groups or ß-substituted Carry allyl groups, preferably styrene; but also, for example, nuclear chlorinated and -alkylated or -alkenylated styrenes, the alkyl groups having 1 to 4 carbon atoms may contain, e.g. B. vinyltoluene, divinylbenzene, oC-methylstyrene, tert.-butylstyrene, Chlorostyrenes; Vinyl esters of carboxylic acids having 2-6 carbon atoms are preferred Vinyl acetate; Vinyl pyridine, vinyl naphthalene, vinyl cyclohexane, acrylic acid and methacrylic acid and / or their esters (preferably vinyl, allyl and methallyl esters) with 1-4 carbon atoms in the alcohol component, its amides and nitriles, maleic anhydride, -half- and diesters with 1-4 carbon atoms in the alcohol component, half and diamides or cyclic imides such as N-methyl maleimide or N-cyclohexyl maleimide; Allyl compounds such as allylbenzene and allyl esters such as allyl acetate, diallyl phthalate, diallyl isophthalate, Diallyl fumarate, allyl carbonates, diallyl carbonates, triallyl phosphate and triallyl cyanurate.

The following examples illustrate the invention.

EXAMPLES Example 1 (reaction a) To a solution of 0.1 mol of benzophenone in 150 ml of absolute tetrahydrofuran at 0-50 ° C., a solution of 0.1 mol of magnesium tert-butyl chloride is obtained dropped into 200 ml of absolute tetrahydrofuran. After stirring for 2 hours at room temperature the solution is allowed to flow slowly into 300 g of ice water, stirred for one hour and separates the organic phase. The aqueous phase is once more with tetrahydrofuran extracted, the combined organic phases are dried and at 10-150 C concentrated in vacuo.

22.5 g of a yellow oil, the polymerization-initiating oil, remain as residue Has properties.

EXAMPLE 2 (Reaction n) To a solution of 0.1 mol of benzophenone in 150 ml of absolute tetrahydrofuran is a solution of 0.1 mol of magnesium (o-chlorobenzyl) chloride at 0-5 ° C added dropwise in absolute tetrahydrofuran. After stirring for 2 hours at room temperature 0.06 mol of methylethoxydichlorosilane are added and then another 3 hours stirred at room temperature.

The batch is then poured into 300 g of ice water and the organic ones are separated Phase off. The aqueous phase is extracted once more with diethyl ether and the combined organic phases are dried and at 0-15 ° C in a vacuum to constant weight constricted.

Residue: 32.5 g of a resinous substance.

Example 3 (reaction p) To a solution of 0.1 mol of benzophenone in 200 ml of absolute tetrahydrofuran is a solution of 0.1 mol of lithium isopropyl at 0-50 ° C Added dropwise in 800 ml of dried hexane.

After stirring for 2 hours at room temperature, 0.06 mol of dichlorodimethylsilane is added added and then for a further 3 hours, first at room temperature, then at 450 C led.

The batch is then poured into 300 g of ice water and separated organic phase. After extracting the aqueous phase with diethyl ether the organic phases combined, dried and concentrated.

Residue: 22 g of yellow, highly viscous oil.

In the following examples mean - unless otherwise noted - the parts listed are parts by weight, the percentages listed are percentages by weight.

Example 4 An uns. Polyester resin, prepared from 11 parts of o-phthalic anhydride, 47 parts of maleic anhydride and 42 parts of 1,2-propylene glycol at 2000 C (acid number 20, OH number 30 viscosity at 200: 1500 cP) 66 Xig is dissolved in styrene and mixed with 0.01 part of sydro quinone stabilized. 0.3 part of the example is then stirred 1 obtained initiator and fills 20 g of the resin batch into a test tube of 16 mm inner shower knife.

An iron-constantan thermocouple with a temperature-time recorder is connected, is dipped centrally into the resin to a depth of 3 cm The test tube is placed in a heating bath that is thermostated to 800 C, and the recorder switched on at the same time.

The polyester resin gels after 2 minutes and reaches after 3.5 minutes a maximum temperature of 2250 C.

Example 5 Example 4 is repeated, but the initiator content is increased to 0.5 parts. The bath temperature is set to 600.degree. The polyester resin gels after 3 minutes and reaches a maximum temperature of after 5.0 minutes 2050 C.

Example 6 Example 4 is repeated, but the initiator content is increased increased to 1.0 parts. The bath temperature is set to 500.degree. The polyester resin gels after 3 minutes and reaches a maximum temperature of 1950 after 6 minutes C.

Example 7 Example 4 is repeated, but the initiator is after Example 1 replaced by 0.3 parts of the initiator after reaction d. The bath temperature is 80 ° C. The resin gels within 5 minutes and reaches after another 3 minutes a maximum temperature of 2150 C.

Example 8 Example 4 is repeated, but instead of the bitiatrs NaS game1 0.3 parts of the initiator stirred in after reaction c.

At a bath temperature of 1100 C the resin hardens within 3.5 Minutes completely. The maximum temperature is above 2500 C.

Example 9 Example 4 is repeated, but instead of the initiator according to example 1 0.3 parts of the initiator obtained according to example 2 are added. At a bath temperature of 1000 C, the resin reaches its peak temperature after 3 minutes from 255 C.

Example 10 Example 4 is repeated, but instead of the initiator according to example 1 0.3 parts of the initiator are added after reaction q.

The bath temperature is set to 1200.degree. Reached after 2.7 minutes the resin the maximum temperature of 2700 C.

Example 11 (comparison) Example 4 is repeated; as initiator however, 0.8 parts of benzopinacol are added. At a bath temperature of 1000 C the curing time is 10.5 minutes. The maximum temperature reached 1960 C.

Example 12 Per 100 parts of styrene are mixed with 0.2 parts of a catalyst mixed.

The solutions are divided into 3 reaction vessels and in one tempered to 1100 C thermostatic bath. After certain times there will be one Sample taken from which the polymerized styrene by diluting it five times Volume of methanol is precipitated.

After one hour, the precipitated polystyrene is filtered off with suction, several times Washed with methanol and then overnight in a vacuum drying cabinet at 600 dried.

The following amounts of polymerized styrene were obtained: Catalyst obtained [%] polystyrene after reaction 30 min / 110 ° C 60 min / 110 ° C 120 min / 110 ° C AP 11.4 16.6 25.4 B q 4.4 10.2 18.5 C n 9.1 13.2 25.0 D Di-tert-butyl peroxide 4.8 6.2 15.2 E no catalyst - - 0.7 The reaction was terminated at an estimated conversion of 30% for reasons of measurement technology. The advantageous effect of the initiators to be used according to the invention results from comparison with the results D).

Example 13 33.3 goat solutions of butyl acrylate in toluene with 0.1 parts of the initiators after reactions n, p and q and mixed in several Portions of 30 g each heated to the boil. Samples are taken after certain times, which is mixed with 1 ml of a 4% solution of hydroquinone in ethyl acetate and then be poured into an open bowl. The solvents are through 1 6 hours Heating to 1000 C evaporated and the residual monomers by tempering the residue removed at 160 ° C in a vacuum etching cabinet (200 Torr).

The gravimetric determination of the residues gives the following proportions of polymerized substance (% of the weight of butyl acrylate): initiator polymerization time [Min.] 15 30 60 120 n 15 34 57 78 p 2.5 is 47 42 q 17 38 65 90

Claims (1)

Claim: Use of reaction mixtures obtained by reacting (1) metal alkyls, aryls or aralkylenes of the formula wherein M is Na, Li, MgCl, MgBr or MgBr, R1 and R2 are a hydrogen atom, an alkyl radical with 1 - 4 carbon atoms, a phenyl or benzyl radical and R3 is an alkyl radical with 1 - 4 carbon atoms or a phenyl radical, with (2) diaryl ketones of the formula wherein R4 and R5 denote a hydrogen, chlorine or fluorine atom, an alkyl radical having 1-4 carbon atoms, methoxy, a phenyl or benzyl radical, and (3) subsequent reaction with (a) water, (b) acid halides of the formula in which X is a chlorine or bromine atom and R6 is an alkyl radical with 1-4 C atoms, a phenyl or benzyl radical, (c) acid anhydrides of the formula in which R7 and R8 denote an alkyl radical having 1-4 carbon atoms or a phenyl radical, or (d) silanes of the formula in which Y denotes a chlorine or bromine atom, methyl, ethyl, phenyl, R10 and R11 denote a chlorine or bromine atom, an alkyl radical having 1-4 carbon atoms, a phenyl radical or an alkoxy radical having 1-3 carbon atoms , as initiators for polymerization reactions that can be initiated by free radicals.