Composition to produce support sub-structures for 3D photopolymer jetting

Abstract

The present invention is directed to a UV-curable composition capable of producing a 3D-printed support sub-structure for photopolymer jetting, and to a 3D-printing processes using said support material composition, and to a 3D-printed articles obtainable with said 3D-printing processes. The composition comprises a N-acryloyl glycinamide type monomer, anoptional hydrophilic co-monomer, a hydrophilic dispersion medium or water, a photoinitiator, and an optional functional additive or combination thereof, at specific contents.

Claims

1. A UV-curable composition, comprising (a) at least one monomer which produces hydrogen bond forming repeating units upon polymerization; (b) optionally at least one hydrophilic co-monomer having one co-polymerizable double bond in each molecule; (c) at least one hydrophilic dispersion medium or water; (d) at least one photoinitiator; and (e) optionally at least one component of a functional additive or combination thereof; wherein the contents of (a), (b) and (d) are, based on the total weight of the composition, (a): 5%˜34% by weight; (b): 1.5%˜15% by weight, if present in the composition; and (d): 0.1%˜10% by weight; respectively; wherein component (a) is at least one N-acryloyl glycinamide type monomer of the formula
CH.sub.2═CR.sub.1—(C═O)—NH—X(C═O)—NR.sub.2R.sub.3 where X is —(CH.sub.2).sub.x1—, x1 is an integer of 1 to 10, or X is —(CH.sub.2CH.sub.2O).sub.x2—,x2 is an integer of 1 to 5; R.sub.1 is H or CH.sub.3; R.sub.2 and R.sub.3 is each independently H or —C.sub.mH.sub.2m+1, m is an integer of 1 to 4.

2. The composition of claim 1, wherein (b) is present in the composition and the ratio of the content of (b) and (a) is 0.05 to 0.45 by weight.

3. The composition of claim 1, wherein X is —(CH.sub.2).sub.x1— wherein x1 is 1 to 6, or X is —(CH.sub.2CH.sub.2O).sub.x2—, wherein x2 is 1 to 2.

4. The composition of claim 1, wherein R.sub.2 and R.sub.3 is independently selected from the group consisting of H, methyl group, ethyl group and propyl group.

5. The composition of claim 1, wherein the at least one N-acryloyl glycinamide type monomer (a) is of the formula
CH.sub.2═CH—(C═O)—NH—CH.sub.2—(C═O)—NH.sub.2,
CH.sub.2═CH—(C═O)—NH—CH.sub.2—(C═O)—NHCH.sub.3,
CH.sub.2═CH—(C═O)—NH—CH.sub.2—(C═O)—NHC.sub.2H.sub.5,
CH.sub.2═CCH.sub.3—(C═O)—NH—CH.sub.2—(C═O)—NH.sub.2,
CH.sub.2═CCH.sub.3—(C═O)—NH—CH.sub.2—(C═O)—NHCH.sub.3,
CH.sub.2═CH—(C═O)—NH—(CH.sub.2).sub.2—(C═O)—NH.sub.2, or
CH.sub.2═CH—(C═O)—NH—(CH.sub.2).sub.2—(C═O)—NHCH.sub.3.

6. The composition of claim 1, wherein (b) is present in the composition and is water soluble.

7. The composition of claim 1, wherein (b) is present in the composition and is selected from the group consisting of acryloyl morpholine, 4-hydroxybutyl acrylate, (meth)acrylic acid, 2-Hydroxylethyl (meth)acrylate, hydroxypropyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N-vinylformamide, (meth)acrylamide, N-hydroxyethyl (meth)acrylamide, and sodium (meth)acrylate.

8. The composition of claim 1, wherein (c) is water soluble.

9. The composition of claim 1, wherein (c) does not having any co-polymerizable double bond.

10. The composition of claim 1, wherein (c) is selected from the group consisting of ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol and glycerol.

11. The composition of claim 1, wherein the content of (a) is 10%˜30% by weight.

12. The composition of claim 1, wherein (b) is present in the composition and the content of (b) is 5%˜12% by weight.

13. The composition of claim 1, wherein the content of (a) is 15%˜30% by weight, (b) is present in the composition and the content of (b) is 5%˜12% by weight, the ratio of the content of (b) and (a) is 0.2 to 0.4 by weight.

14. The composition of claim 1, wherein the content of (d) is 0.5%˜5% by weight.

15. The composition of claim 1, wherein the total contents of (a) to (e) is 100% by weight.

16. A photopolymer jetting 3D-printing process, wherein drops of liquid photopolymers as build material and the composition of claim 1 as support material are jetted onto a build platform through inkjet print heads separately to form a layer of pattern and then cured by UV light in such a way that, with the printing process repeated layer by layer, the two materials form a composite structure with two sub-structures, to form a 3D-printed article of the build material supported by a 3D-printed support sub-structure, followed by removal of the 3D-printed support sub-structure using warm water.

17. The process of claim 16 wherein warm water is neutral water at 30 to 90° C.

18. The process of claim 16 wherein the removal of 3D-printed support sub-structure is performed under ultrasonication, stirring, jetting and/or washing.

19. A 3D-printed article formed in the process of claim 16.

20. The composition of claim 1, wherein (b) is present in the composition and is water-miscible.

Description

EXAMPLES

(1) The implementation of the present invention will be demonstrated by the examples below, although the scope of the present invention is by no means limited to these examples.

Example 1

(2) NAGA used in the examples is the compounds with the structure of CH.sub.2═CH—(C═O)—NH—CH.sub.2—(C═O)—NH.sub.2, and the NAGA-NCH.sub.3 used in the examples is the compounds with the structure of CH.sub.2═CH—(C═O)—NH—CH.sub.2—(C═O)—NHCH.sub.3.

(3) NAGA and NAGA-NCH.sub.3 are synthesized in-house using the procedure described in Support Information of Dai, X. et al. Adv. Mater. 27, 3566-3671 (2015). 4-HBA, EG, TPO, ACMO, and PG are obtained from Sigma Aldrich, St. Louis, Mo., USA, under the trade name of 4-hydroxybutyl acrylate, ethylene glycol, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, acryloyl morpholine, and propylene glycol, and are used as received.

(4) The composition as listed in Table 1 was produced by mixing the components (e), (b), (c) and (d) in a 250 ml beaker and was stirred at room temperature with shielding of UV light from a FE300 UV LED lamp emitting UV light at 365 nm of wavelength, and then cured by exposing the mixture to UV light from said UV LED lamp for 10 seconds.

(5) TABLE-US-00001 TABLE 1 Component Component Component Component Example (a) (b) (c) (d) E1 NAGA 20 g 4-HBA 5 g EG 75 g TPO 1 g E2 NAGA 20 g ACMO 5 g EG 75 g TPO 1 g E3 NAGA 20 g EG 80 g TPO 1 g CE1 acryl 20 g EG 80 g TPO 1 g amide CE2 acryl 20 g ACMO 5 g EG 75 g TPO 1 g amide

(6) During the experiments, the compositions listed as UV-curable in Table 2 were convert into solid, gel-like materials. The produced materials were tested for warm water solubility by immersing in warm water at specified temperature under ultrasonication. The testing result is also shown in Table 2. Other composition listed as not UV-curable in Table 2 remains as liquid after the exposure to the UV light.

(7) TABLE-US-00002 TABLE 2 UV- Soluble in warm water Soluble in warm water Example curability* at 50° C. with ultrasonication at 90° C. E1 Yes Yes (soluble within 23 min) — E2 Yes Yes (soluble within 15 min) — E3 Yes No (insoluble after 120 min) Yes (soluble within 60 min) CE1 No — — CE2 No — — *UV-curability is determined as “Yes” if the liquid composition converts into a solid, gel-like material after UV-curing (the products are then tested for warm water solubility by immersing in warm water at specified temperature under ultrasonication), and as “No” if not.

(8) Table 2 clearly shows that successful formation of gel and dissolution of gel in warm water at 50° C. or 90° C. can be achieved with the combination of NAGA type monomer as monomer (a) and a mono-functional hydrophilic co-monomer as the optional monomer (b). However, warm water at 90° C. is required to dissolve the gel when the co-monomer (b) is absent, while only warm water at 50° C. is required when the co-monomer (b) is present. Furthermore, without NAGA type monomer as monomer (a), there is no gel formed after polymerization.

Example 2

(9) A series of experiments are conducted using the same procedure of Example 1 but different amount/type of components (a) to (d). The results are listed in Table 3.

(10) TABLE-US-00003 TABLE 3 A B C D E F G H I Component A NAGA (g) 25 20 20 20 20 40 20 20 NAGA-NCH.sub.3 (g) 30 Component B ACMO (g) 5 10 4-HBA (g) 5 10 10 7.5 5 8 Component C EG (g) 75 75 75 70 70 50 62.5 72 PG (g) 75 Component D TPO (g) 1 1 1 1 1 1 1 1 1 Gel properties UV-curability* Yes Yes Yes No No No Yes Yes Yes Mechanical property** Good Good Good — — — Good Good Good Warm water solubility*** No Yes Yes — — — Yes Yes Yes [b]/[a] by weight 0 0.25 0.25 0.5 0.5 0.25 0.25 0.25 0.4 *UV-curability is determined as “Yes” if the liquid composition converts into a solid, gel-like material after UV-curing, and as “No” if the liquid composition remains to be liquid state. **Mechanical property is determined as “Good” if the solid, gel-like material formed after UV-curing has storage modulus (G′) higher than 100 Pa at 30° C., and as “Poor” if not. ***Warm water solubility is determined as “Yes” if the solid, gel-like material is dissolved in water within 30 minutes at 50° C. under ultrasonication, and as “No” if not.

(11) It can be seen that satisfactory result has been achieved when the content of (a) is 20-25% by weight of the composition, the content of (b) is 5-10% by weight of the composition, and the ratio of the content of (b) and (e) [b]/[a] is between 0.25 to 0.4. It should be noticed that only satisfying the requirement on the contents of (a) to (d) is not sufficient. For example, using 20 g of NAGA, 10 g of ACMO and 1 g of TPO doesn't lead to formation of gel. On the other hand, in a similar experiment, with 20 g of NAGA, 5 g of 4-HBA and 1 g of TPO, the present invention can be carried out successfully.

(12) Table 3 also shows that it is possible to use NAGA type monomer other than NAGA itself to implement the present invention.

(13) The present invention therefore comprises the following embodiments. 1. A composition which can form a 3D-printed support sub-structure supporting a 3D-printed build sub-structure during jetting 3D-printing, said 3D-printed support sub-structure is crosslinked via hydrogen bonding formed by repeating units derived from a monomer in the composition, said hydrogen bonding is broken when contacting with warm water after the completion of jetting 3D-printing so that the 3D-printed support sub-structure can be removed, leaving the 3D-printed build sub-structure as final product. 2. A UV-curable composition, comprising (a) at least one monomer which produces the hydrogen bond forming repeating units upon polymerization; (b) optionally at least one hydrophilic co-monomer having one co-polymerizable double bond, preferably C═C double bond in each molecule; (c) at least one hydrophilic dispersion medium or water; (d) at least one photoinitiator; and (e) optionally at least one component of a functional additive or combination thereof; wherein the contents of (a), (b) and (d) are, based on the total weight of the composition, (a): 5%˜34% by weight; (b): 1.5%˜15% by weight, if present in the composition; and (d): 0.1%˜10% by weight; respectively. 3. The composition of item 2, wherein component (a) is at least one N-acryloyl glycinamide type monomer of the formula
CH.sub.2═CR.sub.1—(C═O)—NH—X—(C═O)—NR.sub.2R.sub.3 where X is —(CH.sub.2).sub.x1—, x1 is an integer of 1 to 10, or X is —(CH.sub.2CH.sub.2O).sub.x2—, x2 is an integer of 1 to 5; R.sub.1 is H or CH.sub.3; R.sub.2 and R.sub.3 is each independently H or —C.sub.mH.sub.2m+1, m is an integer of 1 to 4; 4. The composition of item 2 or 3, wherein (b) is present in the composition and the ratio of the content of (b) and (a) is 0.05 to 0.45 by weight, preferably 0.05 to 0.4 by weight; more preferably 0.2 to 0.4 by weight. 5. The composition any one of item 2 to 4, wherein X is —(CH.sub.2).sub.x1— wherein x1 is 1 to 6, more preferably 1 to 4, or X is —(CH.sub.2CH.sub.2O).sub.x2—, wherein x2 is 1 to 2. 6. The composition of any one of items 2 to 5, wherein R.sub.2 and R.sub.3 is independently selected from the group consisting of H, methyl group, ethyl group and propyl group; preferably at least one of R.sub.2 and R.sub.3 is H. 7. The composition of any one of items 2 to 4, wherein the N-acryloyl glycinamide type monomer (a) is of the formula
CH.sub.2═CH—(C═O)—NH—CH.sub.2—(C═O)—NH.sub.2,
CH.sub.2═CH—(C═O)—NH—CH.sub.2—(C═O)—NHCH.sub.3,
CH.sub.2═CH—(C═O)—NH—CH.sub.2—(C═O)—NHC.sub.2H.sub.5,
CH.sub.2═CCH.sub.3—(C═O)—NH—CH.sub.2—(C═O)—NH.sub.2,
CH.sub.2═CCH.sub.3—(C═O)—NH—CH.sub.2—(C═O)—NHCH.sub.3,
CH.sub.2═CH—(C═O)—NH—(CH.sub.2).sub.2—(C═O)—NH.sub.2, or
CH.sub.2═CH—(C═O)—NH—(CH.sub.2).sub.2—(C═O)—NHCH.sub.3 8. The composition of any one of items 2 to 7, wherein (b) is present in the composition and is water soluble, preferably is water-miscible. 9. The composition of any one of items 2 to 8, wherein (b) is present in the composition and is selected from the group consisting of acryloyl morpholine, 4-hydroxybutyl acrylate, (meth)acrylic acid, 2-Hydroxylethyl (meth)acrylate, hydroxypropyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N-vinylformamide, (meth)acrylamide, N-hydroxyethyl (meth)acrylamide, and sodium (meth)acrylate. 10. The composition of any one of items 2 to 9, wherein (c) is water soluble, preferably is water-miscible. 11. The composition of any one of items 2 to 10, wherein (c) does not having any co-polymerizable double bond. 12. The composition of any one of items 2 to 11, wherein (c) is selected from the group consisting of ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol and glycerol. 13. The composition of any one of items 2 to 12, wherein (d) is selected from the group consisting of Darocur BP, Darocur 1173, Darocur 4265, Irgacure 184, Irgacure 250, Irgacure 369, Irgacure 379, Irgacure 651, Irgacure 754, Irgacure 819, Irgacure 2022, Irgacure 2100, Irgacure 2959, Irgacure TPO, and Irgacure TPO-L. 14. The composition of any one of items 2 to 13, wherein the content of (a) is 10%˜30% by weight, preferably 15%˜30% by weight. 15. The composition of any one of items 2 to 14, wherein (b) is present in the composition and the content of (b) is 5%˜12% by weight. 16. The composition of any one of items 2 to 13, wherein the content of (a) is 15%˜30% by weight, (b) is present in the composition and the content of (b) is 5%˜12% by weight, the ratio of the content of (b) and (a) is 0.2 to 0.4 by weight. 17. The composition of any one of items 2 to 16, wherein the content of (d) is 0.5%˜5% by weight. 18. The composition of any one of items 2 to 17, wherein the total contents of (a) to (e) is 100% by weight. 19. A photopolymer jetting 3D-printing process, wherein drops of liquid photopolymers as build material and the composition of any of items 1 to 18 as support material are jetted onto a build platform through inkjet print heads separately to form a layer of pattern and then cured by UV light in such a way that, with the printing process repeated layer by layer, the two materials form a composite structure with two sub-structures, to form a 3D-printed article of the build material supported by a 3D-printed support sub-structure, followed by removal of the 3D-printed support sub-structure using warm water. 20. The process of item 19 wherein warm water is neutral water at 30 to 90° C., preferably 40 to 60° C., more preferably about 50° C. 21. The process of item 19 or 20 wherein the removal of 3D-printed support sub-structure is performed under ultrasonication, stirring, jetting and/or washing. 22. A 3D-printed article formed in the process of any one of items 19 to 21.

(14) Unless otherwise indicated, all numbers expressing quantities of components, reaction conditions, dimensions, physical characteristics, processing parameters, and the like, used in the specification are to be understood as being modified in all instances by the term “about”. Accordingly, unless indicated to the contrary, the numerical values set forth in the specification may vary depending upon the desired properties sought to be obtained by the present invention.