3d printing process and molding produced by this process using lignosulfate

Patent metadata

Field	Value
Publication number	US-2022371267-A1
Application number	US-202017772338-A
Country	US
Kind code	A1
Filing date	Oct 29, 2020
Priority date	Nov 1, 2019
Publication date	Nov 24, 2022
Grant date	—

Abstract

The present invention relates to a material system for 3D printing, to a 3D printing process using a lignin-containing component or derivatives thereof or modified lignins, to soluble moldings that are produced by a powder-based additive layer manufacturing process and to the use of the moldings.

First claim

1 . A material system suitable for a 3D printing process or a 3D printing process material system comprising or consisting of:
a particle material and a printing liquid, wherein the particle material is selected from the group consisting of inorganic particle materials such as quartz sand, olivine sand, kerphalite, cerabeads, ceramics, metal powder or other organic particle materials such as wood powder, starch powder or cellulose powder, the particle material preferably being untreated, wherein the printing liquid comprises or consists of: i) a liquid component selected from the group consisting of water and an aqueous solution; and ii) a lignin-containing component or derivatives thereof, preferably lignosulfonate.

2 . The material system according to claim 1 , wherein the liquid component consists of or comprises polar organic or/and inorganic liquids, preferably water and/or alcohols, preferably
wherein the material system additionally contains a soluble starch hydrolysate, e.g. maltodextrin, glucose, preferably wherein the dextrose equivalent of the starch hydrolysate is between 1 and 50, preferably between 3 and 35, particularly preferably between 3 and 20, preferably the alcohol content is between 0.5%-15%, preferably 2%-10%, particularly preferably 5%-8%, and/or wherein the alcohols comprise simple alcohols, diols or polyols or mixtures of the above, or/and wherein the printing liquid has a viscosity of 2 mPas-20 mPas, preferably 5 mPas-15 mPas and particularly preferably 10 mPas-14 mPas.

3 . The material system according to claim 2 , wherein the printing liquid further comprises surfactants, such as sodium dodecyl sulfate or Surfynol 465 , and has a surface tension of 20 mN/m-50 mN/m, preferably 25 mN/m-40 mN/m and particularly preferably 28 mN/m-35 mN/m, or/and comprises defoaming agents from, for example, the group of siloxanes or/and dyes, or/and wherein the printing liquid contains further rheological and dispersing additives which improve the wetting of the components used, for example Zetasperse® 170, Zetasperse® 179, Carbowet® GA221, Surfynol AD01, and corrosion inhibitors.

4 . A 3D printing process for producing a molding, said process comprising the steps of:
applying a particle material mixture onto a build plane, selectively applying a printing liquid, wherein the printing liquid comprises:
i) a liquid selected from the group consisting of water and an aqueous solution; and
ii) a lignin-containing component or derivatives thereof, preferably lignosulfonate, for at least partial selective solidification,
optionally tempering the build field or introducing energy into the applied particle material mixture, preferably tempering to 30° C. to 60° C., more preferably 40° C. to 50° C., and the printing liquid, and repeating these steps until the desired molding has been obtained.

5 . The 3D printing process according to claim 4 , wherein the obtained molding is separated from the non-solidified particle material mixture and the molding is preferably subjected to a further heat treatment step and/or a treatment with microwave radiation.

6 . The 3D printing process according to claim 4 , wherein the particle material mixture is applied by means of a recoater, or/and wherein the printing liquid is selectively applied with a print head, or/and wherein the molding is left in a powder bed at ambient conditions for 4 h-24 h, preferably 8 h-15 h, more preferably 10 h-11 h, after completion of the printing process.

7 . The 3D printing process according to claim 4 , wherein the molding is dried and/or cured by sucking a gas or gas mixture, preferably ambient air, through the entirety of non-printed and printed areas after completion of the printing process, wherein suction preferably takes place 0 h-24 h, preferably 0 h-12 h, particularly preferably directly after the end of printing, suction preferably takes place for 0.5 to 2 hours, preferably for 1 hour, and preferably the molding has a strength of 150 N/cm 2 to 200 N/cm 2 or/and
wherein in an additional step the molding is subjected to a heat treatment, preferably the molding is stored 0.5 h-7 h, preferably 1 h-6 h, at 30° C.-160° C., preferably at 50° C.-140° C., wherein preferably the heat treatment is carried out before and/or during and/or after the printing process by means of an IR lamp in a supporting manner, or wherein, in an additional step, the molding is subjected to a treatment with microwave radiation, the treatment taking place over a period of 2 min-30 min, preferably 2 min-15 min, particularly preferably 2 min-10 min.

8 . The 3D printing process according to claim 4 , wherein the surface of the molding is further coated or sealed.

9 . The 3D printing process according to claim 4 , with a material system comprising:
the particle material mixture and the printing liquid, wherein the particulate material mixture includes a particle material selected from the group consisting of quartz sand, olivine sand, kerphalite, cerabeads, ceramics, metal powder, wood powder, starch powder and cellulose powder, wherein the particle material is untreated, wherein the printing liquid comprises: i) a liquid component selected from the group consisting of water and an aqueous solution; and ii) a lignin-containing component including lignosulfonate.

10 . A molding produced by a 3D printing process according to claim 4 , wherein the molding, left in the powder bed at ambient conditions for 4 h-24 h, preferably 8 h-15 h, particularly preferably 10 h-11 h, has strengths of 80 N/cm 2 -150 N/cm 2 in the direction of printing and, after heat treatment for 1 h-7 h, preferably 4 h-6 h, at 30° C.-160° C., preferably at 50° C.-140° C., has strengths of more than 200 N/cm 2 , preferably from 180 to 250 N/cm 2 , more preferably 240 N/cm 2 .

11 . The material system according to claim 1 , wherein the lignin-containing component includes lignosulfonate.

12 . The material system of claim 11 , wherein the material system additionally contains a soluble starch hydrolysate, wherein
the dextrose equivalent of the starch hydrolysate is between 1 and 50; wherein the alcohol content is between 0.5%-15%, the alcohols comprise simple alcohols, diols or polyols or mixtures of the above; and the printing liquid has a viscosity of 2 mPas-20 mPas.

13 . The material system according to claim 12 , wherein
the printing liquid further comprises a surfactant; and the printing liquid has a surface tension of 20 mN/m to 50 mN/m; and the printing liquid comprises a defoaming agent; and the printing liquid comprises a rheological and dispersing additives which improve the wetting of the components used.

14 . The 3D printing process of claim 4 , wherein the lignin-containing component includes lignosulfonate.

15 . The 3D printing process of claim 8 , wherein the lignin-containing component includes lignosulfonate; and
the method comprises the step of tempering the build field or introducing energy into the applied particle material mixture, to 30° C. to 60° C.

16 . The 3D printing process of claim 5 , wherein
the process comprises the step of tempering the build field or introducing energy into the applied particle material mixture, to 30° C. to 60° C.; and the molding is subjected to a further heat treatment step and/or a treatment with microwave radiation.

17 . The 3D printing process of claim 5 , wherein the particle material mixture is applied by means of a recoater,
the printing liquid is selectively applied with a print head, and the molding is left in a powder bed at ambient conditions for 4

Assignees

• Voxeljet Ag

Inventors

• Gnüchtel Ingo
• Mögele Florian

Classifications

• B29C33/3814

  Porous moulds (adapted for vacuum forming B29C51/365) · CPC title

• B29C64/264

  Arrangements for irradiation · CPC title

• B29C33/3842

  Manufacturing moulds, e.g. shaping the mould surface by machining · CPC title

• B29C39/26

  Moulds or cores · CPC title

• B29C33/52

  soluble or fusible {(in particular used in injection moulding B29C45/4457)} · CPC title