WO2020002745A1

WO2020002745A1 - Reinforced filament for 3d printing

Info

Publication number: WO2020002745A1
Application number: PCT/FI2018/050496
Authority: WO
Inventors: Mikko Huttunen; Timo Lehtonen; Arto MESKANEN; Marjo KETONEN
Original assignee: Arctic Biomaterials Oy
Priority date: 2018-06-26
Filing date: 2018-06-26
Publication date: 2020-01-02

Abstract

A reinforced composite filament comprises a polymer matrix comprising biode- gradable thermoplastic polymer, copolymer, polymer blend, or copolymer blend of synthetic and/or at least partly biological origin, and as reinforcement short glass 5 fibers and nucleating agent mixed within the polymer matrix.

Description

REINFORCED FILAMENT FOR 3D PRINTING

F1ELD OF THE INVENTION

The present invention relates to three-dimensional printing, and more particularly to fibre-reinforced filament for three-dimensional printing.

BACKGROUND

The following background description art may include insights, discov eries, understandings or disclosures, or associations together with disclosures not known to the relevant art prior to the present invention but provided by the pre sent disclosure. Some such contributions disclosed herein may be specifically pointed out below, whereas other such contributions encompassed by the present disclosure the invention will be apparent from their context.

Fused filament fabrication (FFF), also known as fused deposition mod elling (FDM), is a 3D printing process that uses a continuous filament of a thermo plastic material as a raw material to produce 3D printed objects. FFF is currently the most popular 3D printing method ln FFF the three dimensional (3D) printers typically use a thermoplastic filament which is heated to its melting point and then extruded, layer by layer, to create a 3D-printed object. Objects created with a 3D printer are designed as computer-aided design files. Before an object is 3D printed, the file is converted to a format understood by a 3D printer. FFF 3D printers use plastics material which constitutes the finished object, and a support material which acts as a support for the object as it is being 3D printed. During 3D printing, the plastic raw material which is in the form of a filament, is unwound from a coil and fed through an extrusion nozzle. The nozzle melts the filament and extrudes it onto a base, also called a build platform or table. Both the nozzle and the base may be controlled by a control computer that translates the dimensions of an object into X, Y and Z coordinates for the nozzle and base to follow during printing ln a typical 3D printer system, the extrusion nozzle moves over the build platform horizontally and vertically, drawing a cross section of an object onto the platform. The thin layer of plastic thus formed cools and hardens, readily binding to the layer beneath it. Once the 3D printed object comes off the 3D printer, the optional support material is removed.

ln FFF, the thermoplastic polymer raw material may be in the form of a premanufactured, and solidified polymer tow / polymer filament. The polymer fil ament is fed through the nozzle in which the polymer filament is heated above the melting temperature of the matrix polymer (i.e. the thermoplastic polymer). The nozzle is connected to the control computer which is controls the printing of the polymer filament on predetermined three dimensional (X-Y-Z) paths to form a de sired structure of the final 3D part.

Mechanical properties of 3D printed objects manufactured by using the fused filament fabrication (FFF) technique are limited due to the fact that these ob jects typically are composed of polymer only ln addition to technologies which use continues fiber reinforcements, approaches to increase the mechanical properties include the use of chopped glass fibers, carbon fibers, carbon nano tubes, etc. A re cent technique introduced a rotating extruded nozzle where the rotating nozzle en- ables to orient the chopped fibers in the 3D printed part.

SUMMARY

The following presents a simplified summary of features disclosed herein to provide a basic understanding of some exemplary aspects of the inven tion. This summary is not an extensive overview of the invention lt is not intended to identify key/critical elements of the invention or to delineate the scope of the invention lts sole purpose is to present some concepts disclosed herein in a sim plified form as a prelude to a more detailed description.

According to an aspect, there is provided the subject matter of the inde pendent claims. Embodiments are defined in the dependent claims.

One or more examples of implementations are set forth in more detail in the description below. Other features will be apparent from the description, and from the claims.

The present invention enables a considerable improvement of the me chanical properties of 3D printed objects manufactured by using the fused filament fabrication (FFF) technique. This is achievable by utilizing a short glass fibers and a nucleating agent in the polymer filament.

DETA1LED DESCRIPTION OF THE INVENTION

The following embodiments are exemplary. Although the specification may refer to "an", "one", or "some" embodiment(s) in several locations, this does not necessarily mean that each such reference is to the same embodiment(s), or that the feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments. Furthermore, words "comprising", "containing" and "including" should be understood as not lim iting the described embodiments to consist of only those features that have been mentioned and such embodiments may contain also features/structures that have not been specifically mentioned.

An embodiment discloses a composite filament composition, and use of a reinforced composite filament for 3D printing to form a 3D printed product.

ln an embodiment, the reinforced composite filament is a high strength composite filament comprising polymer matrix material which is reinforced with short glass fibers (SGF) and crystal nucleating agent. The high strength composite filament may further include other additive (s), such as additional reinforcements containing or prepared from one or more agents which further enhance and /or improve materials mechanical properties or mechanical performance. Other addi tives may also include one or more of impact modifiers, colorants, mineral fillers, other nucleating agents, fire retardants, hydrolysis resistant additives, UV resistant additives, stabilizers, etc.

An exemplary high strength composite filament contains polyfalpha- hydroxy acid) based (i.e. PLA-based) polymer as the matrix polymer material in which the SGF reinforcement and nucleating agent (such as LAK) are melt mixed. Optionally, the high strength composite filament may also include other additives, such as impact modifiers, colorants, fire retardants, mineral fillers, other nucle ating agents, hydrolysis resistant additives, UV resistant additives, etc.

ln an embodiment, the PLA-based polymer matrix comprises PLA, PLA co-polymer, PLA polymer blend, and/or PLA copolymer blend ln addition or in stead of PLA-based (co)polymer (blend), the polymer matrix in the filament may comprise any other polyfalpha-hydroxy acid), such as polyglycolide (PGA), poly- glycolide copolymer, polyglycolide polymer blend, polyglycolide copolymer blend, polycaprolactone (PCL), polycaprolactone copolymer, polycaprolactone polymer blend, polycaprolactone copolymer blend, poly(lactic-co-glycolic acid) (PLGA), poly(lactic-co-glycolic acid) blend, trimethylene carbonate (TMC) polymer, tri methylene carbonate copolymer, trimethylene carbonate polymer blend, and/or trimethylene carbonate copolymer blend. The polymer matrix may further com- prise any other thermoplastic polymer, for example (but not limited to), PC (poly carbonate), PBS (polybutylene succinate), PHB (polyhydroxybutyrate), PHBV (poly b-hydroxy butyrate-co-p-hydroxy valerate), PHA (polyhydroxyalkanoate), and/or PBAT (polybutyrate adipate terephthalate), as the blended polymer. A PLA copol ymer may be copolymer of L-lactide and D-lactide and any other monomer(s) co- polymerizable with PLA. The reinforcement of the high strength composite filament comprises chopped (i.e. short) glass fibers having an average length of 0.01 - 20 mm, and an average diameter of 0.1 - 500 gm. The amount of SGF in the high strength compo site filament is 1 - 70 wt-%, preferably 5 - 55 wt-%.

The high strength composite filament may optionally contain nucleating agent such as LAK in an amount of 0.1 - 10 wt-%, preferably 0.1 - 5 wt-%.

The base material (i.e. the polymer matrix material) of the high strength composite filament contains biodegradable polymer and/or biobased polymer or polymer blend. The biodegradable polymer and/or biobased polymer may be a ho- mopolymer or a copolymer, including random copolymer, block copolymer, or graft copolymer. Further, the biodegradable polymer and/or biobased polymer may be a linear polymer, a branched polymer, or a dendrimer. The polymers may be of natural (biological) and/or synthetic origin. The copolymers or polymer blends may be of natural (biological) and/or synthetic origin.

The use of the SGF reinforcement increases the strength properties of the PLA-based filament by about 1 - 500% when compared to plain matrix polymer filament without the SGF reinforcement.

The use of a nucleating agent such as LAK increases the degree of crys tallinity of the polymer matrix material. The use of a nucleating agent such as LAK additionally increases the strength of the polymer matrix material. The increased degree of crystallinity leads to better dimensional stability of the polymer matrix material, it increases the strength properties and the heat deflection temperature. Thus the 3D printed part composed of polymer matrix material containing nucle ating agent such as LAK, may be used in higher temperatures compared to 3D printed parts composed of polymer matrix material without nucleating agent.

The reinforced composite filament reinforced with SGF enables obtain ing a 3D printed objects having an increased mechanical strength. This effect is fur ther enhanced by the use of the nucleating agent such as LAK.

PLA refers to polylactide which is a biodegradable thermoplastic ali- phatic polyester which may be synthetic or derived from renewable resources such as corn starch, cassava roots, chips or starch, or sugarcane. Thus PLA may be of synthetic origin and/or biological origin. PLA is considered to be a bioplastic and it is biocompatible.

lf other polyfalpha-hydroxy acids), such as (but not limited to) PGA, PCL, PLGA and/or TMC, are used instead of or in addition to PLA, they may be of synthetic or renewable origin. LAK refers to aromatic sulfonate derivate, such as LAK-301 (trade name), which is a nucleating agent for PLA based polymers, such as (but not limited to) PLA, PGA, PCL, PLGA or TMC resin, enabling the provision of higher degree of crystallinity at lower loading amounts, if compared to typical talc.

The high strength composite filament may have an average diameter of about 0.1 mm to 20 mm, preferably 1.75 mm to 2.85 mm.

Adding chopped (short) fiber reinforcements (i.e. short glass fibers, SGF) to the PLA-based polymer to obtain the reinforced composite filament re markably improves the mechanical properties of the objects 3D printed from such material. This is especially advantageous in applications where the 3D printed product needs to endure mechanical loading. The addition of fibers reduces ther mal expansion of the material, and therefore material including glass fiber filling is dimensionally more accurate.

The reinforced composite filament in accordance with an exemplary embodiment is usable for 3D printing of objects to be used in the fields of medicine, healthcare, agriculture and/or food industry, for example.

ln an embodiment, instead of or in addition to PLA based polymer, other biodegradable and/or at least partly biologically-originated thermoplastic poly mer, copolymer, polymer blend, or copolymer blend is used as the polymer matrix material.

ln an embodiment, the reinforced composite filament consists only of the PLA-based polymer matrix reinforced with SGF and including the nucleating agent such as LAK.

Exemplary embodiments also involve a method for manufacturing of the reinforced composite filament, use of the reinforced composite filament for 3D printing, a 3D printed product, and a method for the preparation of the 3D printed product.

ln an embodiment, a reinforced composite filament comprises a poly mer matrix comprising biodegradable thermoplastic polymer, copolymer, polymer blend, or copolymer blend of synthetic and/or at least partly biological origin, and, as reinforcement, short glass fibers and nucleating agent mixed within the polymer matrix.

ln an embodiment, the polymer matrix comprises polyfalpha-hydroxy acid).

ln an embodiment, the polymer matrix may contain or consist of at least one of polylactide (PLA) polymer, polylactide copolymer, polylactide polymer blend, polylactide copolymer blend, polylactide terpolymer blend polyglycolide (PGA), polyglycolide copolymer, polyglycolide polymer blend, polyglycolide copol ymer blend, polycaprolactone (PCL), polycaprolactone copolymer, polycaprolac- tone polymer blend, polycaprolactone copolymer blend, poly(lactic-co-glycolic acid) (PLGA), poly(lactic-co-glycolic acid) blend, trimethylene carbonate (TMC) polymer, trimethylene carbonate copolymer, trimethylene carbonate polymer blend, and trimethylene carbonate copolymer blend.

ln an embodiment, the filament may further contain one or more addi tives mixed within the polymer matrix, wherein the additive is selected from one or more of a mineral filler, impact modifier, colorant, fire retardant, hydrolysis re sistant additive, UV resistant additive, and stabilizer.

ln an embodiment, the nucleating agent is aromatic sulfonate derivate. ln an embodiment, the polymer matrix is present in the filament in an amount of 10 wt-% to 99 wt-%, preferably 45 wt-% to 95 wt-%.

ln an embodiment, the short glass fibers are present in the filament in an amount of 1 wt-% to 90 wt-%, preferably 5 wt-% to 55 wt-%.

ln an embodiment, the nucleating agent is present in the filament in an amount of 0.1 wt-% to 10 wt-%, preferably 0.1 wt-% to 5 wt-%.

ln an embodiment, the short glass fibers have an average diameter of 0.1 gm to 500 mih, preferably 0.1 gm to 50 gm.

ln an embodiment, the short glass fibers have an average length of 0.01 mm to 20 mm, preferably 0.1 mm to 5 mm.

ln an embodiment, the filament has an average diameter of 0.1 mm to 20 mm, preferably 1.75 mm to 2.85.

ln an embodiment, a method for manufacturing the reinforced compo site filament, comprises mixing the short glass fibers, nucleating agent and option ally one or more additives with molten polymer matrix to obtain a composite mix ture, and processing the composite mixture directly into form of filament in single melt processing step.

ln an embodiment, a method for manufacturing the reinforced compo site filament, comprises mixing the short glass fibers, nucleating agent and option ally one or more additives with molten polymer matrix to obtain a composite mix ture, processing the composite mixture into pellets, and melt processing the pellets to form the reinforced composite filament.

ln an embodiment, the filament is used as a raw material for 3D printing to form a 3D printed part. ln an embodiment, a 3D-printed product comprises or consists of said filament.

ln an embodiment, a 3D printing process comprises subjecting said fil ament to 3D printing in a 3D printer to form a 3D printed part.

ln an embodiment, the 3D printing comprises fused filament fabrication

FFF.

EXAMPLE 1

The high strength composite filament was manufactured and tested in 3D printing by means of fused filament deposition (FFD). Composite filament con sisting of 84 wt-% PLA, 15 wt-% SGF and 1 wt-% LAK were manufactured by means of melt processing in compounding extrusion into form of high strength composite filament having a diameter of 1.75 mm. The obtained high strength composite fila ment was successfully used as a raw material in 3D printing by means of fused fil ament deposition (FFD).

EXAMPLE 2

The high strength composite filament was manufactured and tested in 3D printing by means of fused filament deposition (FFD). Composite pellets con- sisting of 84 wt-% PLA, 15 wt-% SGF and 1 wt-% LAK were manufactured by means of melt processing in compounding extrusion. The composite pellets were further melt-processed to form a high strength composite filament having a diameter of 1.75 mm. The obtained high strength composite filament was successfully used as a raw material in 3D printing by means of fused filament deposition (FFD).

EXAMPLE 3

3D printed parts having different PLA based compositions were pre pared from filaments formed of PLA based compositions. A heat deflection temper ature, bending strength, and bending modulus for said parts were measured ac- cording to standards 1SO 75 with method A for HDT (determination of temperature of deflection under load) and 1SO 178 (Plastics: determination of flexural proper ties). The results of the measurements are shown below in Table 1. As shown in Table 1, a considerable improvement in the bending strength and bending modulus for parts containing SGF, was observed. Further, as shown in Table 1, a considera- ble improvement in the heat deflection temperature, bending strength and bending modulus for parts containing SGF and LAK, was observed. Table 1

Even though the invention has been described above with reference to examples, it is clear that the invention is not restricted thereto but can be modified in several ways within the scope of the appended claims. Therefore, all words and expressions should be interpreted broadly and they are intended to illustrate, not to restrict, the embodiment.

lt will be obvious to a person skilled in the art that, as the technology advances, the inventive concept can be implemented in various ways. The inven tion and its embodiments are not limited to the examples described above but may vary within the scope of the claims.

Claims

CLA1MS

1. A reinforced composite filament comprising

a polymer matrix comprising biodegradable thermoplastic polymer, co polymer, polymer blend, or copolymer blend of synthetic and/or at least partly bi- ological origin; and

as reinforcement short glass fibers and nucleating agent mixed within the polymer matrix.

2. A filament of claim 1, wherein the polymer matrix comprises poly(al- pha-hydroxy acid).

3. A filament of claim 1 or 2, wherein the polymer matrix contains or consists of at least one of

polylactide (PLA) polymer, polylactide copolymer, polylactide polymer blend, polylactide copolymer blend, polylactide terpolymer blend polyglycolide (PGA), polyglycolide copolymer, polyglycolide polymer blend, polyglycolide copol- ymer blend, polycaprolactone (PCL), polycaprolactone copolymer, polycaprolac- tone polymer blend, polycaprolactone copolymer blend, poly(lactic-co-glycolic acid) (PLGA), poly(lactic-co-glycolic acid) blend, trimethylene carbonate (TMC) polymer, trimethylene carbonate copolymer, trimethylene carbonate polymer blend, and trimethylene carbonate copolymer blend.

4. A filament of claim 1, 2 or 3, wherein the filament further contains one or more additives mixed within the polymer matrix, wherein the additive is selected from one or more of a mineral filler, impact modifier, colorant, fire retard ant, hydrolysis resistant additive, UV resistant additive, and stabilizer.

5. A filament of any of the preceding claims, wherein the nucleating agent is aromatic sulfonate derivate.

6. A filament of any of the preceding claims, wherein the polymer matrix is present in the filament in an amount of 10 wt-% to 99 wt-%, preferably 45 wt-% to 95 wt-%.

7. A filament of any of the preceding claims, wherein the short glass fi- bers are present in the filament in an amount of 1 wt-% to 90 wt-%, preferably 5 wt-% to 55 wt-%.

8. A filament of any of the preceding claims, wherein the nucleating agent is present in the filament in an amount of 0.1 wt-% to 10 wt-%, preferably 0.1 wt-% to 5 wt-%.

9. A filament of any of the preceding claims, wherein the short glass fi bers have an average diameter of 0.1 gm to 500 mih, preferably 0.1 gm to 50 gm.

10. A filament of any of the preceding claims, wherein the short glass fibers have an average length of 0.01 mm to 20 mm, preferably 0.1 mm to 5 mm.

11. A filament of any of the preceding claims, wherein the filament has an average diameter of 0.1 mm to 20 mm, preferably 1.75 mm to 2.85.

12. A method for manufacturing the reinforced composite filament of any of the preceding claims, the method comprising

mixing the short glass fibers, nucleating agent and optionally one or more additives with molten polymer matrix to obtain a composite mixture;

processing the composite mixture directly into form of filament in sin- gle melt processing step.

13. A method for manufacturing the reinforced composite filament of any of the preceding claims, the method comprising

processing the composite mixture into pellets; and

melt processing the pellets to form the reinforced composite filament.

14. Use of the filament of any of the preceding claims 1 to 11 as a raw material for 3D printing to form a 3D printed part.

15. A 3D-printed product comprising or consisting of the filament of any of claims 1 to 11.

16. A 3D printing process comprising

subjecting the filament of any of the preceding claims 1 to 11 to 3D printing in a 3D printer to form a 3D printed part.

17. A use of claim 14 or process of claim 16, wherein the 3D printing comprises fused filament fabrication FFF.