Method for producing shaped bodies

Patent metadata

Field	Value
Publication number	US-2018281294-A1
Application number	US-201615769908-A
Country	US
Kind code	A1
Filing date	Aug 26, 2016
Priority date	Aug 26, 2016
Publication date	Oct 4, 2018
Grant date	—

Abstract

A generative process for the manufacture of three-dimensional mouldings is characterized by constructing the moulding stepwise by site-specific delivery of a structure-forming material in liquid form, where a second material is additionally delivered as a supportive material into regions which are intended to remain free from the structure-forming material, and is removed once the structure-forming material has been solidified. The supportive material exhibits low shrinkage upon cooling and is particularly stable in the cooled state and further exhibits low surface roughness.

First claim

1 .- 13 . (canceled)

14 . A process for the additive manufacturing of mouldings by site-specific delivery of a structure-forming material (“sfm”) comprising:
delivering simultaneously or at staggered intervals at least one supportive material (“sm”) into regions which are to remain free from sfm,
where the delivery of the sm is achieved by a device which has at least one delivery unit for the sm positionable in x-, y- and z-directions with a precision of at least ±100 μm which delivers sm in a site-specific manner in the x, y-operating plane and also in the z-direction, successively constructs a supportive structure made of sm for the moulding,
with the proviso that the sm, at 70° C. is a pseudoplastic, viscoelastic composition comprising
(A) a polyether composition comprising
(A1) at least one first polyether having a melting point lower than 35° C. and
(A2) at least one second polyether having a melting point of 35° C. or higher,
wherein the proportion of the second polyether (A2) based on the total weight of the polyether composition (A) is 5% by weight or more to 70% by weight or less,

(B) at least one particulate rheological additive, and
(C) optionally other additional substances,
the polyether composition (A) having a shear viscosity of at most 10 Pas measured at 70° C. with shear rate 100 s −1 using a rheometer with plate-on-plate geometry with a diameter of 25 mm at a gap width of 300 μm,
has a storage modulus G′ of at least 100 Pa, measured at 70° C., and a solidification temperature of from 20° C. or more up to 60° C. or less,
and once the manufacturing of the moulding has been concluded, removing the sm from the moulding, wherein the melting points are determined by DSC according to DIN EN ISO 11357-3, and the solidification temperature is obtained from a temperature sweep measurement under dynamic shear stress on a rheometer with plate-on-plate geometry, diameter 25 mm and gap width of 300 μm, wherein the sample is cooled in a stepwise manner from 70° C. to 20° C. at a cooling rate of 1.5 K/min and the sample is stressed with a constant deformation of 0.1% at a constant frequency of 10 Hz.

15 . The process of claim 14 , wherein the first polyether (A1and the second polyether (A2) are independently of one another selected from the group consisting of
polyethylene glycol, polypropylene glycol, polyethylene glycol-polypropylene glycol copolymers, and monoethers thereof.

16 . The process of claim 14 , wherein the first polyether (A1) is selected from the group consisting of
polyethylene glycols and/or monoethers thereof having a number-average molar mass Mn of less than 1000 g/mol, polypropylene glycols and/or monoethers thereof having a number-average molar mass Mn of less than 2000 g/mol and polyethylene glycol-polypropylene glycol copolymers and/or monoethers thereof having a number-average molar mass Mn of less than 2000 g/mol, wherein the number-average molar mass Mn is determined by size exclusion chromatography.

17 . The process of claim 14 , wherein the second polyether (A2) is selected from the group consisting of
polyethylene glycols and/or monoethers thereof having a number-average molar mass Mn of 1000 g/mol or more and polyethylene glycol-polypropylene glycol copolymers or monoethers thereof having a number-average molar mass Mn of 2000 g/mol or more, wherein the number-average molar mass Mn is determined by size exclusion chromatography.

18 . The process of claim 16 , wherein the second polyether (A2) is selected from the group consisting of
polyethylene glycols and/or monoethers thereof having a number-average molar mass Mn of 1000 g/mol or more and polyethylene glycol-polypropylene glycol copolymers or monoethers thereof having a number-average molar mass Mn of 2000 g/mol or more,
wherein the number-average molar mass Mn is determined by size exclusion chromatography.

19 . The process of claim 14 , wherein the first polyether (A1) is a polyethylene glycol having a number-average molar mass Mn of less than 1000 g/mol, wherein the number-average molar mass Mn is determined by size exclusion chromatography.

20 . The process of claim 14 , wherein the second polyether (A2) is a polyethylene glycol having a number-average molar mass Mn of 1000 g/mol or more, wherein the number-average molar mass Mn is determined by size exclusion chromatography.

21 . The process of claim 19 , wherein the second polyether (A2) is a polyethylene glycol having a number-average molar mass Mn of 1000 g/mol or more, wherein the number-average molar mass Mn is determined by size exclusion chromatography.

22 . The process of claim 14 , wherein the first polyether (A1) is a polyethylene glycol having a number-average molar mass Mn of less than 800 g/mol, wherein the number-average molar mass Mn is determined by size exclusion chromatography.

23 . The process of claim 14 , wherein the second polyether (A2) is a polyethylene glycol having a number-average molar mass Mn of 2000 g/mol or more, wherein the number-average molar mass Mn is determined by size exclusion chromatography.

24 . The process of claim 22 , wherein the second polyether (A2) is a polyethylene glycol having a number-average molar mass Mn of 2000 g/mol or more, wherein the number-average molar mass Mn is determined by size exclusion chromatography.

25 . The process of claim 14 , wherein the proportion of the second polyether (A2) based on the total weight of the polyether composition (A) is 10% by weight or more to 65% by weight or less.

26 . The process of claim 14 , wherein the proportion of the second polyether (A2) based on the total weight of the polyether composition (A) is 15% by weight or more to 60% by weight or less.

27 . The process of claim 14 , wherein component (B) comprises at least one hydrophobic silica having a silanol group density of less than 1.8 silanol groups per nm 2 determined by acid-base titration.

28 . The process of claim 14 , wherein component (B) comprises at least one hydrophobic silica having a methanol number of at least 30, wherein the methanol number is the percentage proportion of methanol which must be added to a water phase to achieve complete wetting of the silica, wherein complete wetting means a complete sinking of the silica in the water-methanol test liquid.

29 . The process of claim 14 , wherein the sm of the moulding is removed mechanically or by dissolution in a solvent.

Assignees

• Wacker Chemie Ag

Inventors

• Gottschalk-Gaudig Torsten
• Dormeier Siegfried

Classifications

• B29C64/112 Primary

  using individual droplets, e.g. from jetting heads · CPC title

• B29C64/35

  Cleaning · CPC title

• C08L71/02

  Polyalkylene oxides · CPC title

• C08L2205/025

  containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure · CPC title

• C08K3/36

  Silica · CPC title