DE1117870B - Process for increasing the shelf life of curable resin compositions based on unsaturated polyester - Google Patents

Description

Method for increasing the shelf life of curable resin compositions Basis of unsaturated polyester The invention relates to a method for Increasing the shelf life of mixtures of unsaturated polyester resins (I-II) and unsaturated monomers (III) which can be polymerized onto them and which are already catalysts are added, which can be hardened by heat to solid plastics.

1. For the purposes of the invention, unsaturated resins are polyesters understood, which by thermal condensation of o;, ß-unsaturated dicarboxylic acids can be obtained with polyhydric alcohols, - but depending on the desired Activity, some of the unsaturated dicarboxylic acids are replaced by saturated ones can. Of the α, ß-unsaturated dicarboxylic acids, maleic acid is the main one and their anhydride and fumaric acid are of practical importance. From the saturated Dicarboxylic acids are aliphatic, such as succinic acid and adipic acid, as well as aromatic dicarboxylic acids or their possible anhydrides or lower Ester used, such as. B. phthalic acid, endomethylenetetrahydrophthalic acid and their halogenation products.

Of the polyhydric alcohols, glycols such as Ethylene glycol, propylene glycol, butylene glycol, also diethylene glycol and polyethylene glycol, as well as the oxyethylation and oxypropylation products of polyhydric phenols and Bisphenols found technical application.

Of both reaction components, the carboxylic acids and the alcohols, are sometimes monovalent - products such as benzoic acid, stearic acid; Olein, Nonyl alcohol, benzyl alcohol, and the monophenyl ethers of glycols as chain terminators used for the production of low-viscosity polyesters. But also polybasic Carboxylic acids and polyhydric alcohols, such as citric acid, aconitic acid, citraconic acid, Glycerine, pentaerythritol, sorbitol, are used for the production of highly viscous types been.

II, Another group of polyesters which are based on the present Let process stabilize are the products made from saturated dicarboxylic acids and polyhydric unsaturated alcohols produced by esterification or transesterification can be. For example, the following alcohols are meant: glycerol monoallyl ether, Pentaerythritol diallyl ether, the oxyethylation and oxypropylation products of the Mono- and diallylhydroquinone, of 3-mono- or 3,3'-diallyl-4,4'-dioxydiphenyl, the 3-mono- or 3,3'-diallyl compounds of (4,4'-dioxydiphenyl) alkanes, e.g. B. 2,2- (3,3'-Diallyl-4,4'-dioxyethoxyphenyl) propane.

The latter group also includes the unsaturated polycarbonic acid esters, by transesterification from diallyl (4,4'-dioxydiphenyl) alkanes and the diesters of Carbonic acid, such as B. the diphenyl carbonate are obtained. Instead of the aforementioned Allyl compounds can also contain the corresponding mono- or dimethallyl or the Find mono- or dicrotonyl compounds use.

III. The second component of the polymerizable mixtures are those Crosslinkers that consist of vinyl and allyl compounds, but also acrylic and crotonic acid derivatives are widely used.

From the multitude of possible known compounds that are called monomeric Crosslinkers for the groups mentioned under 1 and II - are the named below, which were tested when the inventors were discovered.

Styrene - 3,4-diflorostyrene oc-methylstyrene o- ,: m-, p; fluorostyrene o; -ethylstyrene 2,6-dichlorostyrene α-butylstyrene 2,6-difinorstyrene-vinyltoluene 3-fluoro-4-chlorostyrene Divinylbenzene 3.-Chlor-A - fluorostyrene, o-bromostyrene, 2,4,5-trichlorostyrene, 2,5-dichlorostyrene Dichloromonorstyrene 2, 5-dibromostyrene, vinyl chloride, 3,4-dichlorostyrene, 1,1-dichloroethylene Bromoethylene Isopropenyl butyrate fluoroethylene isopropenyl isobutyrate iodoethylene isopropenyl valerate 1,1 -Dibromoethylene isopropenyl benzoate 1,1 -Difiuoräthylen Isopropenylchlorl, l-Diiodethylene benzoate isopropenyl toluate vinyl acetate isopropenal-L-chloro-vinyl propionate acetate Vinyl butyrate isopropenyl-L-bromo-vinyl isobutyrate propionate vinyl valerate vinyl-a-chloroacetate Vinyl caproate vinyl-a-bromopropio-vinyl benzoate nat vinyl toluate vinyl-a-iodopropionate Vinyl chlorobenzoate vinyl a-chlorobutyrate vinyl methoxybenzoate vinyl a-chlorine valerate Vinyl ethoxybenzoate vinyl a-bromo valerate methyl methacrylate propyl methacrylate allyl chlorocarbonate Butyl methacrylate allyl formate amyl methacrylate allyl acetate hexyl methacrylate allyl propionate Heptyl methacrylate allyl butyrate octyl methacrylate allyl valerate decyl methacrylate allyl caproate Methyl crotonate diallyl phthalate ethyl crotonate diallyl succinate methyl acrylate diethylene glycol butyl acrylate bis (allyl carbonate) ethyl acrylate allyl 3,5,5-trimethyl propyl acrylate hexoate isopropyl acrylate Allyl benzoate amyl acrylate allyl acrylate hexyl acrylate allyl crotonate α-ethylhexyl acrylate Allyl oleate heptyl acrylate allyl chloroacetate octyl acrylate allyl trichloroacetate 3,5-trimethyl acrylate Allyl chloropropionate decyl acrylate allyl chloro valerate dodecyl acrylate pyruvic acid allyl isopropenyl acrylate ester isopropenyl acetate allylaminoacetate isopropylene propionate allylacetoacetate diallyl - 3,4,5,6,7,7 - hexachloro - 4 - endomethylene tetrahydrophthalate, plus the corresponding Methyl esters, and also the esters of alkenyl alcohols, such as ß-ethyl allyl alcohol, ß-propyl allyl alcohol Methyl-a-chloroacrylate, ethyl-a-cyanoacrylate, methyl-a-bromoacrylate, amyl-a-cyanoacrylate Methyl a-fluoroacrylate decyl-oc-cyanoacrylate methyl-aiodoacrylate acrylonitrile ethyl-a-chloroacrylate Methacrylonitrile propyl-a-chloroacrylate ethacrylonitrile isopropyl-ol-bromo-crotononitrile acrylate diallyl maleate amyl-a-chloroacrylate diallyl fumarate octyl-a-chloroacrylate Acrylamide 3,5,5-trimethylhexyl-a-methacrylamide a-chloroacrylate N-phenylacrylamide Decyl-a-chloroacrylate N-methyl-N-phenyl-methyl-x-cyanoacrylate acrylamide It is known that such resins (1-11), dissolved in monomeric crosslinkers (III), form mixtures, which often leads to more through a gentle supply of heat or less hard plastics polymerize.

The unsaturated polyester due to the multitude of possible The properties of the starting materials can be varied as far as possible, are condensed according to known processes at temperatures between 140 and 240 "C, in practice mostly working with an excess of 4 to 10% alcohol component in order to achieve a low acid number of less than 30 if possible. These products have a more or less large group depending on the number of unsaturated groups Activity, so that with highly active types there is always the risk that these resins gelation alone can occur even at these high condensation temperatures or that when the monomers are fed in, crosslinking and thus curing takes place immediately. It has therefore proven to be useful to start the reaction mixtures right at the beginning or add inhibitors shortly before the addition of the monomers. To the as inhibitors The substances used include mainly quinones and phenols, such as B. p-benzoquinone, Chloramil, hydroquinone, 4-tert-butylpyrocatechol, 3-methylpyrocatechol, 4-ethylpyrocatechol, Isopropyl catechol, di-teft.-butylcatechol, di-tert. -butylhydroquinone, di-tert-butyl-p-cresol, 4,4'-butylidenebis (6-tert-butyl-3-methylphenol).

However, as a result of their polymerization retardation, these inhibitors can Effect can only be used in the smallest quantities. The average used Quantities are approximately from 0.01 to 0.1%, based on the polyester-monomer mixtures.

Normally, in practice these are simply referred to as "polyester resin compounds" designated mixtures supplied in this form by the manufacturer to the consumer, which then depending on the type of processing for hot curing organic peroxides or for cold hardening organic peroxides and accelerators and other additives clogs.

These uncatalyzed polyester resin compositions are in spite of the inhibitor additives can only be stored for a limited time, and the processor is instructed in a customary manner to ensure that it is kept cool and to use it as soon as possible. But there is now a number of fields of application, such as polyester molding compounds and resins, one-component fillers and varnishes, pre-impregnated papers, textile and Glass fabrics and mats, decorative foils and veneers, casting compounds and putties, etc., the make it necessary that the polymerizable mixtures already with curing catalysts, provided with fillers, pigments or resin carriers to the end processor must be delivered. These products are delivered as semi-finished products and by hot curing, if necessary under pressure, pressed or cold cast and hot cured or injected into hot molds and subjected to polymerization, so that shaped structures are created as desired.

There are known applications where the proportion of organic peroxides up to about 30 / o, based on the proportion of polymerizable mixture. as Organic peroxides are used or recommended, for example: Di-lauroyl peroxide tert-butyl perbenzoate tert-butyl hydroper-mono-tert-butyl peroxide maleate cyclohexanone peroxide Methyl ethyl ketone peroxide 2,2-bis (tert-butyl succinyl peroxy) butane Diacetyl peroxide 2,4-dichlorobenzoyl benzoyl peroxide peroxide cumene hydroperoxide dicumyl peroxide p-chlorobenzoyl peroxide di-tert-butyl peroxide p-methane peroxide tert-butyl peracetate From the foregoing it is now clear that the storage stabilization of catalyzed polymerizable mixtures by no means solely through the addition of Inhibitors can be achieved, especially since the excessive amount of these substances Curing even up to temperatures of 160 "C can delay so much that the final processing is no longer economical in terms of time and the molded bodies produced as a result of undercrosslinking, they cannot achieve the skill values as they would with the addition of inhibitors which do not offer any shelf-life advantages. Will the inhibitor amounts if only slightly increased above the optimum, there is a certain improvement in the Storage stability, but the curing times are also extended. aside from that has been found in a number of tests that the braking effect of the Inhibitors up to a certain temperature limit depending on the test conditions persists, often above the light-off temperature of the organic peroxide used lay, and then suddenly stops, so that the organic peroxide spontaneously polymerizes initiates and causes severe overheating of the molding, which causes cracks to form and embrittlement of the material occur.

It is known per se, peroxides of the elements of group II Periodic table, such as zinc, barium or cadmium peroxide, as a hardener or as a filler to improve the electrical properties in the production of unsaturated Use polyesters. It is also known that these peroxides simultaneously Contain oxides of the same metals.

However, polyester resin compositions are generally not storable, but harden immediately after mixing. Resin compositions made from unsaturated polyesters with a, B-ethylene grouping and monomers that can be polymerized onto it and organic Peroxides as a catalyst are only effective as an inhibitor when quinones or phenols are added Can be kept for a few weeks at room temperature.

The object of the invention is now the shelf life of this resin composition to increase further without having to accept any disadvantageous side effects such resin masses, for example, also in tropical or subtropical areas can be dispatched and pressed there.

It has now been found that, surprisingly, the inhibitors were added can keep within the limits normally applied to polymerizable mixtures can be added if these mixtures are shipped without curing catalysts while maintaining excellent storage stability when for the resin compositions A magnesium peroxide containing magnesium oxide is also used as an inhibitor. It is particularly surprising that the inorganic peroxide-oxide mixture acts as an inhibitor works and to a certain extent reverses its effect at higher temperatures.

After a number of attempts it can be said that the optimum the peroxide-oxide additions between 0.5 and 5 0 / o, the maximum is 50/0.

It is assumed that the alkaline earth peroxide content in the peroxy oxide 25 0 / o does not fall below.

In addition to the extremely good storage stability of the total mixtures it could also be observed that the addition of the peroxide-oxide component in connection with the organic peroxides used as curing catalysts a much better and more uniform curing of the molded parts and thus a brings improved surface with heat and compression deformation.

When using the magnesium peroxide-oxide mixture, the well-known thickening effect has been observed in some types of resin. This is not in Desirable in all cases, especially when the solutions are in continuous running Machines are reinforced with glass fibers or filled with fillers. That was countered by slowly moving the magnesium peroxide-oxide mixture through itself in the resin dissolving surface impregnation is protected so that the thickening effect does not occur occurs during the time-limited machine cycle. Appropriately the type of resin used in each case is used for this, without the addition of monomers. Will If you want a good flow for the intended use, we recommend the Impregnation with a very dilute alcoholic solution of an aliphatic Fatty acid such as stearic acid.

This is combined with the magnesium oxide grain on the surface to form magnesium stearate around and largely restricts the thickening. The resulting magnesium stearate acts as a lubricant and has no effect on storage stability.

Production of the polyester resin masses, on which no protection is claimed here becomes mass I Through thermal condensation, a polyester resin was made from 928 g of fumaric acid, 529 g of phthalic anhydride and 1180 g of 1,3-butylene glycol were produced. The emerging Quantities of condensed water were drained off during the heating between 135 and 20S "C and the condensation continued up to the acid number 28-.

Then the temperature was reduced to 120 to 130 "C and the resin 0.47 g of hydroquinone were added and dissolved with stirring. After the temperature has dropped at a further 10 to 200 ° C., 335 g of commercially available stabilized styrene are slowly increased added and dissolved in the condensate. The mixture is stirred until cold and after it has been determined of the solids further diluted to 700 / o with styrene.

The addition of hydroquinone is the basic stabilization of all polyester resins absolutely necessary before adding the monomer, if not another suitable one Inhibitor is used. Used to stabilize the resins and the monomers dispensed with, the mixtures already polymerize when the monomers are added the unsaturated resin in the aforementioned quantitatively small order of magnitude and become economically worthless because the products no longer have any technical use can be fed.

The pre-stabilization described is considered a prerequisite for the table below, since it is absolutely necessary as a basis for the production of polymerizable mixtures. Composition II From 3353 g of dioxyethylated bisphenol A of the formula and 981 g of maleic anhydride, with the addition of 0.84 g of hydroquinone, a polyester with an acid number of 24 was produced by thermal condensation within the temperature range from 135 to 220 ° C. with removal of the water, drained into pans and ground. In each case 1200 g of the comminuted polyester are then dissolved in 800 g of commercially available stabilized styrene with heating.

Table 1 1 2 3 4 5 6 Storage of the Poly-organic the beginning of the days when filled (catalyst) inhibitor peroxide-oxide- different temperatures at normal Mixture (catalyst) Mixture temperature Deposit 20 ° C 30 ° C 30 ° C 40 ° C end * Mass I tert-butyl perbenzoate 50% in Plasticizers 100 g 2g - - 5 days 3 days 2 days 8 days 100 g 2g 0.02 g - 11 days 7 days 4 days 14 days Hydroquinone 100 g 2g - 2.5 g 52 days 34 days 18 days 58 days MgO2 / MgO 25:75 100 g 2 g 0.02 g 2.5 g storage after 134 days 57 days storage after Hydroquinone 6 months 6 months canceled canceled Mass I 2,2-bis- (tert.- butylperoxy) - butane, dissolved, 40% in plasticizers 100 g 2g - - 5 days 4 days 3 days 9 days 100 g 2g 0.02 g - 11 days 8 days 6 days 12 days Hydroquinone 100 g 2g - 2.5 g 56 days 26 days 14 days 52 days MgO2 / MgO 100 g 2 g 0.02 g 2.5 g storage after 168 days, 74 days storage after Hydroquinone MgO, / MgO 6 months 6 months canceled canceled Mass I benzoyl peroxide 500 / o paste in plasticizers 100 g 1.5 g - - 2 days 2 days 1 day not tested 100 g 1.5 g 0.02 g - 6 days 4 days 3 days not tested Hydroquinone 100 g 1.5 g - 2.5 g 21 days 9 days 5 days 20 days MgO2 / MgO 100 g 1.5 g 0.02 g 2.5 g 72 days 37 days 18 days 81 days Hydroquinone MgO2 / MgO Table 2 1 2 3 4 5 6 Start of gelation after days when the Poly-Organic Inorganic Filled Different Temperatures merlsler peroxide inhibitor peroxide-oxide 20 ° C mixture bares (catalyst) (including 0 temperature Mixture (catalyst) Mixture (including 30 ° C 40 ° C climatic 30 ° C 40 ° C Swan deposit kungen) end * Mass II tert-butyl perbenzoate 50% in Plasticizers 100 g 2 g - - 21 days 9 days 5 days 28 days 100 g 2g 0.02g - 28 days 16 days 9 days 31 days Di-tert-butyl p-cresol 100 g 2g - 2.5 g 54 days 37 days 26 days 58 days MgO2 / MgO 100 g 2g 0.02 g 2.5 g after after after 96 days after Di-tert-butyl-MgO2 / MgO 6 months 6 months 6 months p-cresol Storage Storage Storage canceled canceled canceled Mass II 2,2-bis (tert.- butylperoxy) - butane, dissolved, 40% in plasticizers 100 g 2g - - 20 days 11 days 4 days 24 days 100 g 2 g 0.01 g quinone - 27 days 15 days 8 days 31 days 100 g 2 g - 2.5 g 108 days 49 days 29 days 102 days MgO2 / MgO 100 g 2 g 0.01 g quinone 2.5 g after after 89 days after MgO2 / MgO 6 months 6 months 6 months canceled canceled canceled Mass II mixture 50% di-tert-butyl- tert-butyl perhydroquinone benzoate with 50% Di-tert-butyl per- oxide 100 g 1 g - - 9 days 4 days 2 days not tested 100 g 1 g 0.02 g -; 14 days 7 days 4 days not tested 100 g 1 g - 2.5 g 66 days 23 days 12 days not tested MgO2 / MgO 100 g 1 g 0.02 g 2.5 g after 124 days 62 days not tested MgO2 / MgO 6 months canceled * 350 g of the mixture of the substances in sections 1 + 2 + 3 + 4 of Tables 1 and 2 were mixed with 350 g of cut glass fibers and 300 g of precipitated calcium carbonate and deposited. It was checked at regular intervals whether the molding compounds could be pressed under pressure and heat to form moldings. The first day of non-compressibility was designated as the end of deposition.

Claims (3)

CLAIMS: 1. Method of increasing the shelf life of curable Resin compounds based on unsaturated polyester with oc, fl-ethylene groupings and monomers which can be polymerized onto them and contain catalyzing amounts of a organic peroxides and inhibiting amounts of quinones or phenols and optionally Fillers, characterized in that as an inhibitor in addition to the usual Inhibitors a magnesium peroxide containing magnesium oxide is used. 2. The method according to claim 1, characterized in that an oxide-containing Magnesium peroxide used with a peroxide content of at least 25% will. 3. The method according to claim 1 and 2, characterized in that the oxide-containing magnesium peroxide in an amount of up to 5 01o of the hardenable resin compound is applied. References considered: U.S. Patents No. 2,308 494, 2,623,030; Ullmann, »Encyclopedia of Industrial Chemistry, Vol. 2, 1928'S.117; Bjorksten, aPolyesters and their Applications, "New York, 1956, pp. 46-72.