USE OF AN ADDITIVE KIT IN 3D PRINTING OF A CONSTRUCTION MATERIAL COMPOSITION

Abstract

The present application relates to an additive component comprising a component A and a component B, wherein component A comprises at least one hardening retarder selected from glyoxylic acid, salts thereof, condensation or addition products of glyoxylic acid or salts thereof, and mixtures thereof, and component B comprises at least one hardening accelerator selected from calcium-silicate-hydrate, calcium formate, calcium nitrate, calcium chloride, calcium hydroxide, lithium carbonate, lithium sulfate, potassium sulfate, sodium sulfate, ground gypsum, and combinations thereof, in 3D printing of a construction material composition.

Claims

1.-15. (canceled)

16. A composition comprising an additive kit comprising a component A and a component B, wherein component A comprises at least one hardening retarder selected from glyoxylic acid, salts thereof, condensation or addition products of glyoxylic acid or salts thereof, and mixtures thereof; and component B comprises at least one hardening accelerator selected from calcium-silicate-hydrate, calcium carbonate, calcium amidosulfonate, calcium acetate, calcium citrate, calcium formate, calcium nitrate, calcium chloride, calcium hydroxide, lithium carbonate, lithium sulfate, potassium sulfate, sodium sulfate, ground gypsum, aluminium salts, slurries of aluminate cements, and combinations thereof; where the composition is a construction material composition for 3D printing.

17. The composition according to claim 16, wherein the hardening retarder is selected from ##STR00030## and A3) an amine-glyoxylic acid condensate selected from the group consisting of a melamine-glyoxylic acid condensate, an urea-glyoxylic acid condensate, a melamine-urea-glyoxylic acid condensate and a polyacrylamide-glyoxylic acid condensate; and mixtures thereof; wherein X is in each case independently selected from H or a cation equivalent K.sub.a, wherein K is an alkali metal, alkaline earth metal, zinc, iron, aluminium, ammonium, or a phosphonium cation, and wherein a is 1/n, wherein n is the valence of the cation.

18. The composition according to claim 17, wherein X is H, Na, K, Li or a mixture thereof.

19. The composition according to claim 16, wherein component A further comprises at least one carbonate source.

20. The composition according to claim 31, wherein the inorganic carbonate is selected from the group consisting of potassium carbonate, sodium carbonate, lithium carbonate, magnesium carbonate, and combinations thereof.

21. The composition according to claim 16 wherein component A further comprises at least one hydroxylic acid or a salt or hydrate thereof.

22. The composition according to claim 21, wherein the hydroxylic acid or salt thereof is selected from the group consisting of citric acid, tartaric acid, gluconic acid, salts, hydrates, and combinations thereof.

23. The composition according to claim 16, wherein the at least one hardening accelerator is selected from the group consisting of calcium-silicate-hydrate, calcium hydroxide, and combinations thereof.

24. The composition according to claim 16, wherein component B further comprises at least one polyhydroxy compound or salts or esters thereof.

25. The composition according to claim 24, wherein the polyhydroxy compound is selected from sugar alkohols and their condensation products, alkanolamines and their condensation products, carbohydrates, pentaerythritol, trimethylolpropane, and combinations thereof.

26. The composition according to claim 16, wherein the construction material composition comprises at least one inorganic binder.

27. The composition according to claim 26, wherein the at least one inorganic binder is a hydraulic binder.

28. A process for producing a construction material 3D structure comprising the steps of (i) mixing component A of the additive kit as defined in claim 16 with a construction material composition as defined in claim 16, water, and optionally further components; and (ii) hardening the mixture of step (i) by adding component B of the additive kit as defined in claim 16.

29. The process according to claim 28, wherein, in step (ii) of the process, component B is added to the mixture of step (i) during the application of the mixture with a 3D printing system.

30. A construction material 3D structure obtained by the process according to claim 28.

31. The composition according to claim 16, wherein component A further comprises at least one inorganic carbonate source.

32. The composition according to claim 21, wherein the hydroxylic acid or salt thereof is trisodium citrate or a hydrate thereof.

33. The composition according to claim 24, wherein the polyhydroxy compound is glycerol.

34. The composition according to claim 26, wherein the at least one inorganic binder is selected from the group consisting of Portland cement, calcium aluminate cement, sulfoaluminate cement, and mixtures thereof.

35. The composition according to claim 26, wherein the at least one inorganic binder is Portland cement.

Description

EXAMPLES

[0249] Preparation of a bisulfite adduct of glyoxylic acid:

[0250] 148 g glyoxylic acid hydrate (50% in water) were charged into a reaction vessel and mixed with 594 g ethanol. 380 g sodium pyrosulfite (Na.sub.2S.sub.2O.sub.5) dissolved in 750g of water were then added to the mixture. After stirring for 4 h the obtained suspension was cooled to 120 C. and allowed to stand for 24 h. The product crystallized and was isolated and dried. It was characterized by means of NMR.

[0251] Component A of an additive kit (hardening retarder):

[0252] 53% by weight sodium carbonate

[0253] 43% by weight bisulfite adduct of glyoxylic acid

[0254] 4% trisodium citrate dihydrate

[0255] Citric acid is used as an alternative hardening retarder in reference examples 3 and 4.

[0256] Component B of an additive kit (hardening accelerator):

[0257] Ca(OH).sub.2 and/or C—S—H and/or glycerol are used in amounts as indicated for each mortar composition (will be dosed to the mortar mixture on the printer nozzle)

[0258] The following mortar compositions have been tested.

TABLE-US-00002 TABLE 1 Ref. 1 Ref. 2 Ex. 1 Ex. 2 Ref. 3 Ref. 4 OPC CEM I 42.5 (Karls-tadt) 335 g 335 g 335 g 335 g 335 g 335 g Limestone powder 30 g 30 g 30 g 30 g 30 g 30 g Micro silica 15 g 15 g 15 g 15 g 15 g 15 g Fly ash 30 g 30 g 30 g 30 g 30 g 30 g Dispersant based on a 0.5 g 0.5 g 0.5 g 0.5 g 0.5 g 0.5 g polycarboxylate ether (Melflux ® 4930 F) Defoamer on the basis of 0.5 g 0.5 g 0.5 g 0.5 g 0.5 g 0.5 g silicone and ethoxylated fatty alcohol (Vinapor ® DF 9010 F) Internal water storage ad- 2 g 2 g 2 g 2 g 2 g 2 g ditive based on salt insen- sitive superabsorbent technology based on crosslinked acrylamide polymer (Starvis ® S 3911 F) Thickener based on 0.1 g 0.1 g 0.1 g 0.1 g 0.1 g 0.1 g acrylamide based thick- ener (Starvis ® T 50) Quartz Sand (0.6-1.2 mm) 267 g 267 g 267 g 267 g 267 g 267 g Quartz Sand (0.2-0.6 mm) 120 g 120 g 120 g 120 g 120 g 120 g Quartz Sand (0.09-0.4 mm) 200 g 200 g 200 g 200 g 200 g 200 g Water 240 g 240 g 240 g 240 g 240 g 240 g Component A — 6 g 6 g 6 g — — Citric acid — — — 1 g 1 g Ca(OH).sub.2 — — 50 g 50 g — 50 g C—S—H — — — 6 g — 6 g Glycerol — — 1.5 g 1.5 g — 1.5 g Results: Ref. 1: 1 hour open time, afterwards the mortar can no longer be pumped and extruded. Hard-ening completed after 2 hours. Ref. 2: 45 min open time, afterwards the mortar can no longer be pumped and extruded. Hard-ening completed after 2 hours. Ex. 1: After addition of Ca(OH).sub.2 and glycerol, hardening is completed within only 15 minutes. Ex. 2: After addition of Ca(OH).sub.2, C—S—H, and glycerol, hardening is completed within only 10 minutes. Ref. 3: >2 hours open time. Ref. 4: Hardening cannot be completed within <45 minutes.

[0259] The results show that the additive kit according to the invention based on component A and component B provides suitable properties for 3D printing regarding hardening retardation in the beginning and hardening acceleration after application with the 3D printer. It is noted that the additional additives used in the above examples, i.e. the dispersant, defoamer, internal water storage additive and the thickener, are not mandatorily required for the effective use of the additive kit according to the invention.