Compositions and methods useful for forming sintered articles
A sintered article may be formed from a composition containing at least sinterable thermoplastic particles and a curable (meth)acrylate resin component, wherein the sinterable thermoplastic particles are insoluble in the curable (meth)acrylate resin component at 25° C. The curable (meth)acrylate resin component may be cured, thereby forming an intermediate article which may be converted into a sintered article using conditions effective to remove at least a portion of the matrix formed by the cured curable (meth)acrylate resin component and to sinter the thermoplastic particles.
1 . A composition comprised of sinterable thermoplastic particles and a curable (meth)acrylate resin component having a viscosity at 25° C. of less than 1500 centipoise, wherein the sinterable thermoplastic particles are insoluble in the curable (meth)acrylate resin component at 25° C. and are comprised of at least one thermoplastic selected from the group consisting of polyaryletherketones and polyimides.
2 . A composition comprised of sinterable thermoplastic particles and a curable (meth)acrylate resin component, wherein the sinterable thermoplastic particles are insoluble in the curable (meth)acrylate resin component at 25° C., wherein the sinterable thermoplastic particles have a glass transition temperature greater than 100° C.
3 . The composition of claim 1 , wherein the sinterable thermoplastic particles have a melting point greater than 250° C., a glass transition temperature greater than 200° C., or a melting point greater than 250° C. and a glass transition temperature greater than 200° C.
4 . The composition of claim 3 , wherein the sinterable thermoplastic particles are comprised of at least one thermoplastic selected from the group consisting of polyetheretherketones, polyetherketoneketones and polyimides.
5 . The composition of claim 2 , wherein the sinterable thermoplastic particles are comprised of at least one thermoplastic selected from the group consisting of polyaryletherketones, polyamides, polyimides, polycarbonates and fluoropolymers.
6 . The composition of claim 5 , wherein the sinterable thermoplastic particles are comprised of at least one thermoplastic selected from the group consisting of polyamides, polyvinylidene fluorides and polycarbonates.
7 . The composition of claim 1 , wherein the sinterable thermoplastic particles have a volume median diameter (Dv50), as measured by a scanning electron microscope when dry, of from 10 to 100 microns.
8 . The composition of claim 1 , wherein the curable (meth)acrylate resin component is photocurable.
9 . The composition of claim 1 , wherein the curable (meth)acrylate resin component is comprised of one or more (meth)acrylate-functionalized monomers or oligomers.
10 . The composition of claim 1 , wherein the curable (meth)acrylate resin component is comprised of one or more (meth)acrylate-functionalized monomers or oligomers containing one or more polyoxyalkylene segments.
11 . The composition of claim 1 , wherein the curable (meth)acrylate resin component is comprised of one or more (meth)acrylate-functionalized monomers or oligomers containing one or more polyoxyethylene, polyoxypropylene or polyoxyethylene/oxypropylene segments.
12 . The composition of claim 1 , wherein the curable (meth)acrylate resin component is comprised of one or more (meth)acrylate-functionalized monomers or oligomers selected from the group consisting of alkoxy polyethylene glycol mono(meth)acrylates, alkoxy polypropylene glycol mono(meth)acrylates, polyethylene glycol di(meth)acrylates, alkoxylated bis-phenol di(meth)acrylates and alkoxylated aliphatic polyalcohol (meth)acrylates.
13 . The composition of claim 1 , wherein the curable (meth)acrylate resin component has a viscosity at 25° C. of less than 800 centipoise.
14 . The composition of claim 1 , wherein the curable (meth)acrylate resin component is additionally comprised of at least one photoinitiator.
15 . The composition of claim 1 , wherein the curable (meth)acrylate resin component is a homogeneous liquid at 25° C.
16 . The composition of claim 1 , wherein the curable (meth)acrylate resin component, when cured, has a decomposition temperature lower than the melting point of the sinterable thermoplastic particles or, if the sinterable thermoplastic particles do not have a melting point, lower than the glass transition temperature of the sinterable thermoplastic particles.
17 . The composition of claim 1 , wherein the composition is comprised of from 25 to 60 weight % sinterable thermoplastic particles and 40 to 75 weight % curable (meth)acrylate resin component based on the total weight of sinterable thermoplastic particles and curable (meth)acrylate resin component.
18 . A method of forming a sintered article, comprising:
a) curing a composition in accordance with claim 1 to form an intermediate article comprised of the sinterable thermoplastic particles bound by a matrix of the curable (meth)acrylate resin component in cured form; and
b) subjecting the intermediate article to conditions effective to remove at least a portion of the matrix and to sinter the sinterable thermoplastic particles, whereby the sinterable thermoplastic particles are fused together to form a sintered article.
19 . The method of claim 18 , wherein the curing in step a) is carried out by irradiating the curable (meth)acrylate resin component.
20 . The method of claim 18 , wherein the conditions in step b) comprise heating the intermediate article at a temperature effective to at least partially decompose the curable (meth)acrylate resin composition in cured form while avoiding decomposition of the sinterable thermoplastic particles.
21 . The method of claim 20 , wherein following heating of the intermediate article the intermediate article comprises decomposition products of the curable (meth)acrylate resin composition in cured form and the intermediate is contacted with a solvent which is effective to remove at least a portion of the decomposition products.
22 . The method of claim 18 , wherein the conditions in step b) comprise compacting the intermediate article.
23 . The method of claim 18 , wherein the conditions in step b) comprise exposing the intermediate article to a laser beam.
24 . The method of claim 18 , wherein the method comprises three dimensional printing.
25 . The method of claim 18 , wherein in step b) removal of at least a portion of the matrix and sintering of the sinterable thermoplastic particles take place concurrently.
26 . The method of claim 18 , wherein in step b) removal of at least a portion of the matrix takes place before sintering of the sinterable thermoplastic particles.
27 . The method of claim 18 , wherein the sintered article is thermoplastic.
28 . A method of making a sintered article, comprising:
a) applying a first layer of a composition in accordance with claim 1 onto a surface;
b) curing the first layer to provide a cured first layer;
c) applying a second layer of the composition onto the cured first layer;
d) curing the second layer to provide a cured second layer adhered to the cured first layer;
e) repeating steps c) and d) a desired number of times to build up a three-dimensional article comprised of the sinterable thermoplastic particles bound by a matrix of the curable (meth)acrylate resin component in cured form; and
f) subjecting the three-dimensional article to conditions effective to remove at least a portion of the matrix and to sinter the sinterable thermoplastic particles, whereby the sinterable thermoplastic particles are fused together to form a sintered article.
29 . A method of making a three dimensionally printed article using digital light projection, stereolithography or multi jet printing, comprising irradiating a composition in accordance with claim 1 in a layer by layer manner to form the three dimensionally printed article.
30 . The composition of claim 5 , wherein the sinterable thermoplastic particles have a melting point greater than 150° C.
31 . The composition of claim 5 , wherein the sinterable thermoplastic particles have a melting point greater than 150° C.
32 . A composition comprised of sinterable thermoplastic particles and a curable (meth)acrylate resin component, wherein the sinterable thermoplastic particles are insoluble in the curable (meth)acrylate resin component at 25° C. and are comprised of at least one thermoplastic selected from the group consisting of polyaryletherketones, and polyimides, wherein the curable (meth)acrylate resin component is a homogeneous liquid at 25° C.
33 . The composition of claim 1 , wherein the at least one thermoplastic comprises polyaryletherketone and the polyaryletherketone is selected from the group consisting of polyetherketoneketone (PEKK), polyetheretherketone (PEEK), polyetherketone (PEK), polyetherketoneetherketoneketone (PEKEKK), and mixtures thereof.
34 . The composition of claim 32 , wherein the at least one thermoplastic comprises polyaryletherketone and the polyaryletherketone is selected from the group consisting of polyetherketoneketone (PEKK), polyetheretherketone (PEEK), polyetherketone (PEK), polyetherketoneetherketoneketone (PEKEKK), and mixtures thereof.