Calcium carbonate hydroxodialuminates comprising a hexagonal platelet-shaped crystal habit

Abstract

A process is provided for preparing calcium carbonate hydroxodialuminates which have a hexagonal platelet-shaped crystal habit and are of the formula (A): Ca m Al 2 (OH) 6+2(m−1) An* n H 2 O  (A) where m=3.5 to 4.5 and An=carbonate which may be partly replaced by perchlorate and/or trifluoromethanesulfonate (triflate) and n=0 to 6, comprising the steps of reacting calcium oxide or calcium hydroxide with optionally activated aluminum oxohydroxide or aluminum hydroxide and simultaneously or subsequently with a carbonate source consisting of carbon dioxide or alkali metal (bi)carbonate and optionally further reacting the product obtained in step (a) with perchloric acid and/or trifluoromethanesulfonic acid or optionally calcining the product obtained in step (a) at 200° C. to 900° C. and subsequently exchanging ions in the presence of a perchlorate and/or triflate salt, optionally in the presence of alkali metal (bi)carbonate, in water. The present invention further relates to the aluminates thus obtained in compositions and stabilizer systems and to the use thereof.

1 . (canceled) 
     
     
         2 . The process as claimed in  claim 8 , wherein m=3.8 to 4.2, An=carbonate which is optionally partly replaced by perchlorate and n=0 to 3. 
     
     
         3 . The process as claimed in  claim 8 , wherein alkali metal carbonate or bicarbonate, preferably sodium or potassium carbonate, is added in step (a). 
     
     
         4 . The process as claimed in  claim 8 , wherein the carbonate source is subsequently converted in step (a). 
     
     
         5 . The process as claimed in  claim 8 , wherein the reaction in step (a) is performed at temperatures of 25-180° C. at ambient pressure or under an elevated pressure of up to 12 bar. 
     
     
         6 . The process as claimed in  claim 8 , comprising the further step of:
 (c) wet grinding the product obtained in step (a) or optionally in step (b), using a solids suspension of 50 to 700 g/l and grinding bodies of 0.2 to 2.0 mm, and the mean particle size of the ground product being <10 μm.   
     
     
         7 . (canceled) 
     
     
         8 . A composition comprising:
 at least one calcium carbonate hydroxodialuminate obtainable from a the process for preparing calcium carbonate hydroxodialuminates; and   calcium hydroxide and/or aluminum hydroxide   wherein the process for preparing calcium carbonate hydroxodialuminates comprises the steps of:   (a) reacting calcium oxide or calcium hydroxide with optionally activated aluminum oxohydroxide or aluminum hydroxide and simultaneously or subsequently with a carbonate source consisting of carbon dioxide or alkali metal carbonate or bicarbonate; and   (b1) optionally further reacting the product obtained in step (a) with perchloric acid and/or trifluoromethanesulfonic acid; or   (b2) optionally calcining the product obtained in step (a) at 200° C. to 900° C. and subsequently exchanging ions in the presence of a perchlorate and/or triflate salt, optionally in the presence of alkali metal carbonate or bicarbonate, in water.   
     
     
         9 . The composition as claimed in  claim 8 , further comprising a synthetic polymer. 
     
     
         10 . The composition as claimed in  claim 9 , wherein the at least one calcium carbonate hydroxodialuminate is present in a concentration of 10 to 70% by weight based on the synthetic polymer. 
     
     
         11 . The composition as claimed in  claim 9 , wherein the synthetic polymer is a thermoplastic and/or a halogenated polymer. 
     
     
         12 . A stabilizer system for synthetic polymers comprising at least one calcium carbonate hydroxodialuminate obtainable from a process for preparing calcium carbonate hydroxodialuminates,
 wherein the process for preparing calcium carbonate hydroxodialuminates comprises the steps of:   (a) reacting calcium oxide or calcium hydroxide with optionally activated aluminum oxohydroxide or aluminum hydroxide and simultaneously or subsequently with a carbonate source consisting of carbon dioxide or alkali metal carbonate or bicarbonate; and   (b1) optionally further reacting the product obtained in step (a) with perchloric acid and/or trifluoromethanesulfonic acid; or   (b2) optionally calcining the product obtained in step (a) at 200° C. to 900° C. and subsequently exchanging ions in the presence of a perchlorate and/or triflate salt, optionally in the presence of alkali metal carbonate or bicarbonate, in water.   
     
     
         13 . The stabilizer system as claimed in  claim 12 , wherein the compounds of the formula (A) are used in amounts of 0.1 to 10 phr, preferably of 0.5 to 5.0 phr and more preferably of 1.3 to 3.0 phr. 
     
     
         14 . The stabilizer system as claimed in  claim 12 , wherein at least one of the following substances is additionally present: calcium hydroxide, a zinc soap, a Ca/Zn stabilizer, a 1,3-diketone—or else as the Ca, Mg, Zn or Al salt thereof—, a polyol (e.g. maltitol, lactitol, palatinitol, pentaerythritol (PE), bis-PE, trimethylolpropane (TMP), bis-TMP or tris(hydroxyethyl) isocyanurate (THEIC)), a phosphorous ester, a glycidyl compound, an epoxidized fatty acid ester, an alkali metal perchlorate/triflate, alkaline earth metal perchlorate/triflate or zinc perchlorate/triflate, undissolved or dissolved in water or in an organic solvent, an aminouracil, dihydropyridine, aminocrotonic ester, a cyanoacetylurea or a perchlorate salt. 
     
     
         15 . A calcium carbonate hydroxodialuminate obtained by a process for preparing calcium carbonate hydroxodialuminates,
 wherein m=3.8 to 4.2, An=carbonate and n=0 to 3, and   wherein the process for preparing calcium carbonate hydroxodialuminates comprises the steps of:   (a) reacting calcium oxide or calcium hydroxide with optionally activated aluminum oxohydroxide or aluminum hydroxide and simultaneously or subsequently with a carbonate source consisting of carbon dioxide or alkali metal carbonate or bicarbonate; and   (b1) optionally further reacting the product obtained in step (a) with perchloric acid and/or trifluoromethanesulfonic acid; or   (b2) optionally calcining the product obtained in step (a) at 200° C. to 900° C. and subsequently exchanging ions in the presence of a perchlorate and/or triflate salt, optionally in the presence of alkali metal carbonate or bicarbonate, in water.   
     
     
         16 . The composition according to  claim 12 , wherein the reaction in step (a) is performed at temperatures of 25-180° C. at ambient pressure or under an elevated pressure of up to 12 bar. 
     
     
         17 . The composition according to  claim 8 , wherein the calcium carbonate hydroxodialuminates have a hexagonal platelet-shaped crystal habit 
     
     
         18 . The composition according to  claim 8 , wherein the process for preparing calcium carbonate hydroxodialuminates are of the formula (A):
   Ca m Al 2 (OH) 6+2(m−1) An* n H 2 O  (A)
   
       where m=3.5 to 4.5 and An=carbonate which may be partly replaced by perchlorate and/or trifluoromethanesulfonate and n=0 to 6.