DE3027005A1 - Retarding gypsum setting - by adding di:alkyl-phosphinyl-alkane phosphonic acid - Google Patents

Abstract

Use of dialkyl-phosphinyl-alkane-phosphonic acids having formula R1R2P(=O)-(CH2)n-PO3H2 (I) (where R1 and R2 are Me, Et or propyl and n is 1 or 2) as gypsum setting-retarders, is new. In pref. (I), R1 and R2 are both Me. The gypsum compsns. include plaster of Paris, putty-, joint plaster etc. (I) are easily prepd. known cpds., have appreciable gypsum-setting retardant activity and allow sufficient gypsum processing time.

Description

Use of dialkylphosphinyl-alkanephosphonic acids as

Gypsum retardant gypsum are inorganic-mineral substances, at least 50% by weight from dehydration products of calcium sulfate dihydrate exist and to which various additives can be added (see for example "Building plaster", DIN standard 1168, sheet 1 from May 1975 and part 2 from July 1975 or F Graf and F. Rausch, "Auxiliary plaster products, their application and effect" in cement-lime-gypsum, Bau Verlag -Wiesbaden, issue 5-1951, pages 1 to 7). When mixed with water, give Plaster a gradually solidifying mass (= setting), which is a firm cohesion Has; In practice, the setting speed of the plaster of paris plays a key role Role, since this naturally affects the processing properties and processing time he influences.

The compounds known from the prior art that delay the setting speed (time) of the gypsum mixed with water include organic polymers such as casein and gelatin, organic carboxylic acids such as citric acid, malic acid and tartaric acid or inorganic acids such as boric acid and phosphoric acid, too the use of appropriate salt forms is known. Organic phosphorus compounds are also already in; relevant literature has been described as a gypsum setting retarder: The phosphonocarboxylic acid compounds according to DE - OS 26 47 042, which have the following general formula [R = alkyl from C1 to C18 (optionally halogen-substituted), H, alkali ion or ammonium ion] are described, can be prepared from the methylene-diphosphonic acid tetraalkyl esters by reaction with acrylic acid esters in a molar ratio of about 1 to 2 in the presence of strongly basic catalysts at 0 ° to 140 ° C and optionally subsequent transesterification or hydrolysis in acidic or alkaline conditions. One of the areas of application for those phosphonocarboxylic acid compounds in which R exclusively denotes H, an alkali and / or ammonium ion, is their use as a plaster set retarder.

Phosphonocarboxylic acid compounds are known from EP-OS 0 000 0.1, which, inter alia, have the following general formula (R¹ = H, alkyl, alkali metal or ammonium ion; R² = alkyl) to be discribed; they can be prepared from the dialkylphosphinylmethanephosphonic acid by reaction with acrylic acid esters in the presence of strongly basic catalysts at 0 ° to 1400 ° C. and, if necessary, subsequent transesterification or hydrolysis in acidic or alkaline conditions. One of the areas of application for those phosphonocarboxylic acid compounds in which R1 exclusively denotes H, an alkali and / or ammonium ion, is their use as a plaster set retarder.

These phosphonocarboxylic acid compounds known from the prior art have a certain delay in the setting speed of the plaster of paris, However, they have to be relatively cumbersome from the phosphinyl methanephosphonic acid ester base bodies getting produced.

The object of the present invention is therefore to be relatively simple to be synthesized to find phosphinyl-alkanephophonic acid compounds that have a cause a significant delay in the setting of the plaster and a sufficient processing time of plaster of paris for the user.

The invention is the use of dialkylphosphinylalkanephosphonic acids of the general formula I, in which R¹ and R² are identical or different and denote methyl, ethyl or propyl groups and n = 1 or 2, as a gypsum setting retarder. In particular, in the compounds of general formula I, R¹ and R² are each a CH3 group.

Examples of compounds of the general formula I are: dimethylphophinyl methanephosphonic acid Methyl-ethyl-phosphinyl-methanephosphonic acid Dietyhlphosphinyl-methanephosphonic acid 2-dimethylphosphinyl-ethanephosphonic acid.

2- (methyl-propyl-phosphinyl) -ethanephosphonic acid.

The compounds are known as such, for example from US Pat 3,646,133, in the anhydrides of organic alkylidene-phosphinyl-phosphine oxides (or phosphinyl-alkanephosphonic acids) are described, the free acids of which i.a.

by the general formula II can be described, whereby i P can be, inter alia, an alkyl radical from C1 to C18; X and Y are hydrogen or alkyl groups from C1 to C6.

By M. I. Kabachnik, T. Y. Medved, I. B. Goryunova, L. I. Tikhonova and E. I. Matrosov in Izv. Akad. Nauk.

SSSR, Ser. Khim. 1974, 10, pp. 2290 to 2295 is the implementation of Describe diethylphosphine oxide with diethyl vinyl phosphonate, after which an acid hydrolysis of the resulting phosphinyl-ethanephosphonic acid ester can connect to 2-diethylphosphinyl-ethanephosphonic acid.

The dimethylphosphinyl methane - un-u 2-dimethylphosphinyl ethane phosphonic acid are from patent application P .. .. - (internal designation (Hoe 80 / K 044) with the title "Dimethylphosphinyl-alkanephosphonic acids, a process for their production and their use as a plaster retarder "known.

The dialkylphosphinylalkanephosphonic acids can be derived from the dialkylphosphinylalkanephosphonic diesters of the general formula III in which R¹, R² and n have the meanings given for general formula I and R3 and R4 are identical or different and mean alkyl groups from C1 to C8, preferably from C to C3, by acidolysis or hydrolysis. The diesters of the general formula III are known, for example from the publications mentioned above. The acidolysis of the diesters can be carried out, for example, with hydrogen chloride, if appropriate in the presence of water, or by reaction with organic carboxylic acids in the presence of catalysts according to the teaching of DE-OS 27 19 385.

The hydrolysis is expediently carried out according to the method of DE-PS 24 41 783 (= US-PS 4,069,247) and 24 41 878 (= US-PS 4,069,245) by reacting with water carried out from a temperature of about 1600 to 1700C. Examples of connections of the general formula III are: Dimethylphosphinyl-methane-phosphonic acid-dimethyl-, diethyl and diisopropyl esters, methyl ethyl phosphinyl methanephosphonic acid diethyl ester Diethylphosphinyl-methanephosphonic acid diethyl ester, methyl propyl-phosphinyl-methanephosphonic acid diethyl ester 2-Dimethylphosphinyl-ethanephosphonic acid dimethyl, diethyl and di-n-propyl ester 2- (methyl-ethyl-phosphinyl) -ethanephosphonic acid diethyl ester the Dialkylphosphinyl-alkanephosphonic acids are used according to the invention as gypsum-setting retarders, in particular in an amount from 0.005 to 0.5 wt. E, preferably from 0.01 to 0.1 % By weight, in each case based on the proportion of gypsum in gypsum-containing mixtures or based on pure plaster. The term "gypsum-containing mixtures" includes in particular Building plaster types such as stucco plaster, plastering plaster, ready-made plastering plaster, adhesive plastering plaster, machine plastering plaster, Plaster of paris, joint plaster or plaster of paris, which in addition to at least 50% by weight dehydrated calcium sulphate dihydrate and other corapons such as calhydrate, thickening agents (i.e. substances which the properties of plaster of paris, for example the consistency, the Adhesion or stiffening) and fillers such as sand or perlite may contain.

The dialkylphosphinylalkanephosphonic acids used according to the invention show over the known organic ones that have hitherto been preferred in practice Carboxylic acids have a significantly higher setting delay, this applies - with comparable Quantities - also with respect to known organophosphorus compounds.

Examples 1 and 2 and Comparative Examples V1 to V4 The in the following Values given in the table for samples examined for their influence on the setting time were made according to the "Vicat" method in accordance with DIN 1168, part 2 (= "test with the immersion cone" under 2.5.2) in the July 1975 edition. In this method of determination the onset of stiffening of mixtures containing gypsum is called Measure for the start of stiffening, the duration is determined in minutes after which an immersion cone at Penetrating a plaster sample gets stuck at a certain height. The duration is calculated from the beginning of the sprinkling of the mixture.

For this purpose, the samples are contained in the plaster of paris and the setting retarder mixed with water in a ratio of sample to water such as 10 to 6 without lumps. That The end of the stiffening (setting time) is reached during the measurement when the rope cone no longer penetrates the plaster sample. Either stucco (= dehydration product of calcium sulphate dihydrates in the low temperature range) = type 1 or a mixture of 95% by weight Stck.gipe and 5 Cew, -% lime @ ydrat = type 2 used.

Of the compounds used in Comparative Examples V1 and V2 Citric acid or tartaric acid is known to be effective when using citric acid in calcareous gypsum masses (e.g. type 2) or from tartaric acid in non-calcareous Plaster of paris (for example type 1) each time to -zl about -) v 50 lower setting time values deliver than in the respective counter type. They were therefore in the more advantageous for them Mass (inserted and compared to this in relatively better values. Both Dialkylphosphinylalkanephosphonic acids used according to the invention are in contrast can be used with good success in addition to these organic carboxylic acids in both types of plaster of paris. Also di: Comparative experiments with the known structurally.

Comparable organophosphorus compounds (V3 and V4) show that at least the dimethylphosphinyl-methanephosphonic acid used in Example 1 produces an at least comparable retarding effect when only half the amount of retarder added is used. Example or pre-equalization amount of the setting time in setting time in Example of the setting retarder in type 1 plaster Type 2 plaster retarder weight% (related (min) (min) on the amount of plaster) start end end end start end Dimethylphosphnyl methane 0.050 after 1,320 minutes still after 480 minutes phosphonic acid (Ex. 1) not set not set 0.025 315 330 154 168 0.020 270 281 138 150 2-dimethylphosphinyl-0.050 160 174 56 7 ethanophonic acid (Ex. 2) Citric acid +) 0.100 205 225 - - (V1) 0.050 105 116 - - Tartaric acid +) (V2) 0.050 - - 173 253 3-Dimethylphosphinyl-3- 0.100 after 1,800 min still - - phosphonopimelic acid ++) not bound (V3) 0.050 330 360 3,3-diphosphonopimeline 0.100 after 390 min still - - acid +++) not set - - 0.075 185 200

published in F. Graf and F. Rausch, Zement-Kalk-Gips (see introduction), values were also determined in the test series) EP-OS 0 000 061, values taken from the table on page 27) DE-OS 26 47 042, value taken from the table on page 12 Summary Use of dialkylphosphinylalkanephosphonic acids as gypsum set retarders The invention relates to the use of diaikylphosphinylalkanephosphonic acids of the general formula I in which R¹ and R² are the same or different and are methyl, ethyl or propyl groups and n = 1 odei is 2, as a gypsum setting retarder, in particular in an amount of 0.005 to 0.5% by weight, based on the gypsum content.

Claims (3)

Claims 1. Use of dialkylphophinyl-alkanephosphonic acids of the general formula I, in which R¹ and R² are identical or different and denote methyl, ethyl or propyl groups and n = 1 or 2, as a gypsum setting retarder. 2. Use according to claim 1, characterized in that R¹ and dcß R² are each CH3. 3. Use according to claim 1 or 2, characterized in that the dialkylphosphinylalkanephophonic acids in an amount of 0.005 to 0.5% by weight, based on the gypsum content.