Polymer reinforced materials for inkjet based 3D printing

Abstract

The present disclosure relates to reinforcing photopolymer resins and uses thereof, e.g., in inkjet 3D printing.

Claims

1. A composition comprising: a UV-curable matrix material, and a reinforcing agent having a solubility in UV-curable matrix material that decreases as the UV-curable matrix material is cured, wherein the reinforcing agent is present at an amount such that: (a) prior to curing the UV-curable matrix material, the reinforcing agent is at least partially dissolved in the UV-curable matrix material, and (b) upon curing the UV-curable matrix material, at least a portion of the reinforcing agent is precipitated, thereby forming a phase-separate domain in the cured UV-curable matrix material.

2. The composition of claim 1, wherein the cured UV-curable matrix material comprises a polymer comprising acrylate.

3. The composition of claim 1, wherein the cured UV-curable matrix material comprises a polymer comprising thiol-ene.

4. The composition of claim 1, wherein the UV-curable matrix material comprises a polymer comprising acrylate and thiol-ene.

5. The composition of claim 1, wherein the reinforcing agent has a higher glass-transition temperature than that of the UV-curable matrix material.

6. The composition of claim 1, wherein the reinforcing agent is non-UV-curable.

7. The composition of claim 1, wherein the reinforcing agent is non-reactive with the UV-curable matrix material.

8. The composition of claim 1, wherein the amount of the reinforcing agent is less than about 20 wt %.

9. The composition of claim 1, wherein the reinforcing agent is polyvinylpyrrolidone.

10. The composition of claim 1, wherein the reinforcing agent is poly(methyl methacrylate).

11. The composition of claim 1, wherein the solubility of the reinforcing agent in the UV-curable matrix material decreases as the UV-curable matrix material is cured by UV irradiation.

12. The composition of claim 1, wherein the amount of the reinforcing agent ranges from about 1.5 wt % to about 5 wt %.

13. The composition of claim 9, wherein the polyvinylpyrrolidone has a molecular weight ranging from about 6000 to about 150000.

14. The composition of claim 10, wherein the poly(methyl methacrylate) has a molecular weight of about 120000.

15. The composition of claim 1, wherein the composition has a viscosity ranging from about 10 cps to about 15 cps.

16. The composition of claim 1, wherein the composition has a viscosity ranging from about 31 cps to about 49 cps at about 30 C., from about 21 cps to about 32 cps at about 40 C., from about 15 cps to about 23 cps at about 50 C., from about 11 cps to about 17 cps at about 60 C., or from about 8 cps to about 13 cps at about 70 C.

17. A cured composition being prepared by a method comprising curing the composition of claim 1.

18. The cured composition of claim 17, wherein the composition is cured by UV irradiation.

19. The cured composition of claim 17, wherein the cured composition has a tensile strength which is from about 30% to about 300% higher than that of a comparable cured composition prepared by curing a composition comprising the UV-curable matrix material in absence of the reinforcing agent.

20. The cured composition of claim 17, wherein the cured composition has a tensile strength that is proportional to the amount of the reinforcing agent in the composition.

21. The cured composition of claim 17, comprising a polymer comprising acrylate.

22. The cured composition of claim 17, comprising a polymer comprising thiol-ene.

23. The cured composition of claim 17, comprising a polymer comprising acrylate and thiol-ene.

24. The cured composition of claim 17, comprising polyvinylpyrrolidone or poly(methyl methacrylate).

25. A composition comprising: a UV-curable matrix material, and polyvinylpyrrolidone or poly(methyl methacrylate), wherein the polyvinylpyrrolidone or poly(methyl methacrylate) is present at an amount such that: (a) prior to curing the UV-curable matrix material, the polyvinylpyrrolidone or poly(methyl methacrylate) is at least partially dissolved in the UV-curable matrix material, and (b) upon curing the UV-curable matrix material, at least a portion of the polyvinylpyrrolidone or poly(methyl methacrylate) is precipitated, thereby forming a phase-separate domain in the cured UV-curable matrix material.

26. A cured composition being prepared by a method comprising curing the composition of claim 25.

27. A composition comprising: a UV-curable matrix material which, upon curing, forms a cured UV-curable matrix material comprising a polymer comprising acrylate, thiol-ene, or the combination thereof, and a reinforcing agent having a solubility in UV-curable matrix material that decreases as the UV-curable matrix material is cured, wherein the reinforcing agent is present at an amount such that: (a) prior to curing the UV-curable matrix material, the reinforcing agent is at least partially dissolved in the UV-curable matrix material, and (b) upon curing the UV-curable matrix material, at least a portion of the reinforcing agent is precipitated, thereby forming a phase-separate domain in the cured UV-curable matrix material.

28. A cured composition being prepared by a method comprising curing the composition of claim 27.

29. A composition comprising: a UV-curable matrix material which, upon curing, forms a cured UV-curable matrix material comprising a polymer comprising acrylate, thiol-ene, or the combination thereof, and polyvinylpyrrolidone or poly(methyl methacrylate), wherein the polyvinylpyrrolidone or poly(methyl methacrylate) is present at an amount such that: (a) prior to curing the UV-curable matrix material, the polyvinylpyrrolidone or poly(methyl methacrylate) is at least partially dissolved in the UV-curable matrix material, and (b) upon curing the UV-curable matrix material, at least a portion of the polyvinylpyrrolidone or poly(methyl methacrylate) is precipitated, thereby forming a phase-separate domain in the cured UV-curable matrix material.

30. A cured composition being prepared by a method comprising curing the composition of claim 29.

Description

EXAMPLE 1

Material: Acrylate Matrix Reinforced by a Vinylpyrrolidone

(1) In this embodiment, IPUC101, an inventor-formulated elastomeric acrylate material, is reinforced by Polyvinylpyrrolidone (PVP) (Mw: 6000-150000). IPUC101 is a self-formulated (see Table 1), elastomeric acrylate material with a tensile strength of 3.4 MPa, elongation at break of 160%, and Shore hardness of 35 A. The reinforcing agent is Polyvinylpyrrolidone (PVP) K15, purchased from Tokyo Chemical Industry Co. Ltd. The reinforcing agent PVP is a polymer known for having high polarity. Because this formulation of IPUC101 includes almost 30% 2-Hydroxyethyl acrylate (HEA), IPUC101 is also polar to some extent. The HEA in the IPUC101 helps the PVP to dissolve or disperse into the uncured material. The reinforcing effect on IPUC101 is a function of both the composition of reinforcing agent and the concentration of the reinforcing agent. In this embodiment using PVP, the molecular weight was shown to have a large effect on the reinforcement.

Preparation of PVP-Reinforced IPUC101

(2) In one embodiment, the desired amount of PVP and IPUC101 were dispensed into a sealed amber bottle. The mixture was stirred at elevated temperature (for example 70 C.) until all solids were dissolved. In another embodiment, the PVP powder and IPUC101 were added into a container and mixed using a Flextek mixer (Flex-Tek Group, Greenwood, S.C., USA) at room temperature until the powder was uniformly dissolved in the solution. Each resulting solution was either clear or slightly cloudy. The inks were stored at room temperature until use.

(3) The reinforcing effect of adding PVP K15 to the IPUC101 formulation is shown in Table 2. The tensile strength and Shore hardness of the material increases as PVP K15 is added to the formulation. The tensile strength of the IPUC101 material without PVP is 3.4 MPa, but increases to 4.6, 7.4, and 9.6 MPa at loading fractions of 1.5%, 3%, and 5% PVP K15 respectively. The Shore A hardness similarly increases from 35 to 38, 40, and 45 respectively. Notably, the elongation at break does not appear to change significantly. Also, of note is the degree of reinforcement at low loading fraction. Typical fillers require 30-100 phr for adequate reinforcement, whereas PVP K15 reinforcement more than doubles the tensile strength at only 3% loading.

(4) TABLE-US-00001 TABLE 1 IPUC101 Formulation Percentage Supplier Function Photomer 6230 29.98 IGM Resins Oligomer 2-Hydroxyethyl acrylate 29 TCI America Monomer SR440 20 Sartomer Monomer Genomer 1121 20 Rahn AG Monomer Omnirad 819 1 IGM Resins Photo initiator MEHQ 0.02 Sigma Photo inhibitor Total 100

(5) TABLE-US-00002 TABLE 2 With and Without PVP K15 Reinforcement: Mechanical Properties Tensile strength Elongation at Hardness (MPa) break (%) (Shore A) IPUC101 3.4 160 35 IPUC101-1.5% K15 4.6 162 38 IPUC101-3% K15 7.4 166 40 IPUC101-5% K15 9.6 160 45

(6) Table 3 below shows how viscosity of the acrylate resin IPUC101 formulation as a function of temperature without any reinforcing filler as well as with varying amounts of reinforcing filler.

(7) TABLE-US-00003 IPUC101 + IPUC101 + IPUC101 + IPUC101 1.5% K-15 3% K-15 5% K-15 30C 30.70 cP 36.65 cP 43.17 cP 49.31 cP 40C 20.76 cP 24.66 cP 28.78 cP 31.81 cP 50C 14.89 cP 17.46 cP 20.19 cP 22.83 cP 60C 11.30 cP 13.09 cP 14.85 cP 16.58 cP 70C 8.48 cP 9.82 cP 11.24 cP 12.55 cP

EXAMPLE 2

Material: Acrylate Matrix Reinforced by a Second Vinylpyrrolidone

(8) In this embodiment, the vinylpyrrolidone is Polyvinylpyrrolidone K12 provided by BASF. The preparation of samples of IPUC101 reinforced with PVP K12 is the same with IPUC101 reinforced by PVP K15 (Mw: 4000-6000). The mechanical properties of PVP K12 reinforced IPUC101 is shown in Table 3. As shown in Table 3, with 5 wt % of loading, there is a 40% of increase in tensile strength. Although the tensile strength was increased, the increase is not as significant as when PVP K15 is the reinforcing agent.

(9) TABLE-US-00004 TABLE 3 PVP K12 Reinforcement: Mechanical Properties Tensile strength Elongation at Hardness (MPa) break (%) (Shore A) IPUC101 3.4 160 35 IPUC101-3% K12 3.7 156 40 IPUC101-5% K12 4.9 161 40

EXAMPLE 3

Material: Thiol-ene Matrix Reinforced by Poly(Methyl Methacrylate) PMMA

(10) In this embodiment, a new Thiol-ene matrix material, TE14, is a self-formulated (see table 4), elastomeric thiol-ene material with a tensile strength of 1 MPa, elongation at break of 107%, and Shore hardness of 30 A. The reinforcing material PMMA (Mw: 120000) was purchased from Sigma.

(11) TABLE-US-00005 TABLE 4 TE14 Formulation Percentage Supplier Function Trimethylolpropane tris(3- 15.15 Sigma Monomer mercaptopropionate) 3,6-dioxa-1,8-octanedithiol 29.6 TCI America Monomer Diallyl phthalate 53.7 TCI America Monomer Vinylphosphonic acid 0.5 TCI America Photo inhibitor Omnirad 651 1 IGM Resins Photo initiator Pyrogallol 0.05 TCI America Photo inhibitor Total 100

Preparation of TE14 reinforced by PMMA

(12) In this embodiment, a desired amount of each of PMMA and TE14 was dispensed into a sealed amber bottle. The mixture was stirred at elevated temperature (for example 70 C.) until all solids were dissolved. Alternatively, PMMA powder and TE14 were added into a container and mixed through a Flextek mixer at room temperature until the powder was dissolved in the solution. The resultant solutions were clear. The composition was stored at room temperature until use.

(13) The reinforcing effect of adding PMMA to the TE14 formulation is shown in Table 5. The tensile strength and Shore hardness of the material increases as PMMA is added to the formulation.

(14) TABLE-US-00006 TABLE 5 Reinforcing Effect of Adding PMMA to the TE14 Formulation Tensile strength Elongation at Hardness (MPa) break (%) (Shore A) TE14 1.0 107 30 TE14-3% PMMA 1.3 236 32 TE14-5% PMMA 1.7 184 35

(15) A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. For example, various forms of the materials shown above may be used, with steps re-ordered, added, or removed. Accordingly, other implementations are within the scope of the following claims.

(16) The examples presented herein are intended to illustrate potential and specific implementations of the present disclosure. The examples are intended primarily for purposes of illustration of the invention for those skilled in the art. No particular aspect or aspects of the examples are necessarily intended to limit the scope of the present invention.

(17) The figures and descriptions of the present invention have been simplified to illustrate elements that are relevant for a clear understanding of the present invention, while eliminating, for purposes of clarity, other elements. Those of ordinary skill in the art may recognize, however, that these sorts of focused discussions would not facilitate a better understanding of the present disclosure, and therefore, a more detailed description of such elements is not provided herein.

(18) Unless otherwise indicated, all numbers expressing lengths, widths, depths, or other dimensions and so forth used in the specification and claims are to be understood in all instances as indicating both the exact values as shown and as being modified by the term about. As used herein, the term about refers to a 10% variation from the nominal value. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Any specific value may vary by 20%.

(19) The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The foregoing embodiments are therefore to be considered in all respects illustrative rather than limiting on the invention described herein. Scope of the invention is thus indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.

(20) It will be appreciated by those skilled in the art that various modifications and changes may be made without departing from the scope of the described technology. Such modifications and changes are intended to fall within the scope of the embodiments that are described. It will also be appreciated by those of skill in the art that features included in one embodiment are interchangeable with other embodiments; and that one or more features from a depicted embodiment can be included with other depicted embodiments in any combination.