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EP-4007688-B1 - ADJUSTABLE CTE POLYMER COMPOSITIONS FOR EXTRUSION AND ADDITIVE MANUFACTURING PROCESSES

EP4007688B1EP 4007688 B1EP4007688 B1EP 4007688B1EP-4007688-B1

Inventors

  • JACKSON, Aubrey Gerald
  • SKELTON, Zachary Ian
  • LUNN, Philip
  • SCHINDLER, Guy Rene

Dates

Publication Date
20260506
Application Date
20200803

Claims (12)

  1. A method of making a composite part, the method comprising: additively manufacturing or extruding a polymer composition to form a tool (110), the polymer composition comprising a polymer matrix (22) and a negative thermal expansion (NTE) additive (16), the polymer composition being configured for additive manufacturing or extrusion; applying a composite part composition or composite part laminate on or to the tool (110); and exposing the tool (110) to sufficient heat to cure the composite part composition or composite part laminate; wherein the amount of the NTE additive (16) in the polymer composition is selected to generally match a coefficient of thermal expansion (CTE) of the tool (110) to the CTE of the composite part.
  2. The method of claim 1, wherein the NTE additive (16) comprises a powder or particulate having an average particle size of about 10 µm or smaller.
  3. The method of claim 1 or claim 2, wherein the NTE additive (16) comprises a material selected from the group consisting of: transition metal tungstates; transition metal molybdates; zirconium vanadates; zeolites exhibiting NTE; aluminum phosphates exhibiting NTE; Prussian blue analogs; antiperovskite manganese nitrides; β-eucryptite; BiNi 1-x Fe x O 3 compounds in which x is less than 1 and greater than 0; Ca 2 RuO 4-γ ; combinations thereof, hybrids thereof, and mixtures thereof.
  4. The method of any one of claims 1 to 3, wherein the NTE additive (16) comprises one or more transition metal tungstates, one or more antiperovskite manganese nitrides, β-eucryptite, a combination thereof, a hybrid thereof, or a mixture thereof.
  5. The method of any one of claims 1 to 4, wherein the polymer composition further comprises one or more auxiliary additives (18, 20), wherein the one or more auxiliary additives (18, 20) optionally comprises one or more strengtheners, one or more magnetically receptive materials, or one or more colorants.
  6. The method of any of claims 1 to 5, wherein the polymer composition further comprises one or more strengtheners.
  7. The method of claim 5 or claim 6, wherein the one or more strengtheners comprises a material selected from the group consisting of carbon fibers, glass fibers, aramid fibers, metal fibers, metal coated fibers, and combinations thereof.
  8. The method of any one of claims 5 to 7, wherein the NTE additive (16) and the one or more strengtheners are present in the polymer composition in a sum total amount of about 1 to about 60 vol% based on the total volume of the polymer composition.
  9. The method of any one of claims 1 to 7, wherein the NTE additive (16) is present in the polymer composition in an amount of about 1 to about 60 vol% based on 100 vol% of the polymer composition.
  10. The method of any one of claims 1 to 9, wherein the additively manufacturing or extruding the polymer composition comprises extruding the polymer composition to form the tool (110), the tool (110) having a constant cross-section.
  11. The method of any one of claims 1 to 9, wherein the additively manufacturing or extruding the polymer composition comprises additively manufacturing the polymer composition to form the tool (110), the tool (110) comprising a net shape.
  12. The method of any of claims 1 to 11, wherein the NTE additive (16) comprises an NTE material coated with a coating material.

Description

BACKGROUND EP 3 459 702 A1 relates to a mold tool with anisotropic thermal properties. Momenzadeh et al. 2019, The International Journal of Advanced Manufacturing Technology, 103:4713-720, investigates the influences of zirconium tungstate additives on polyvinylidene fluoride components. WO 2019/087722 A1 relates to a modified zirconium phosphate tungstate. Molds and cauls, among other structures, are commonly used to fabricate composite parts. These molds, cauls and other structures (also referred to herein as "tools") are typically prepared from metallic or polymeric materials. The polymeric materials often include modifications to the polymers used to make the tools. These modifications are commonly made to impart certain desired properties to the tools post-cure. For example, conventional polymeric materials for the production of these tools have included the addition of certain additives to modify the coefficient of thermal expansion (CTE), increase strength, and reduce warpage in the extruded polymers. These additives have conventionally been incorporated into the tools in fiber form, but polymer modification using fibers has certain limitations, and to date, no compositions incorporating expansion controlling fillers have been developed that are suitable for additive manufacturing and/or extrusion manufacturing processes for manufacturing the tools. For tool manufacturing, one of the major problems with current additive manufacturing techniques is the highly anisotropic behavior of the polymers, and their lack of thermal conductivity. The highly anisotropic behavior of the polymers used in additive manufacturing techniques is a primary result of attempting to control the thermal expansion, strength, and warpage of the printed (i.e., additively manufactured) material (or structure). The polymers used in these manufacturing techniques can be modified by the addition of certain fibers to modify the coefficient of thermal expansion (CTE), increase strength, and/or reduce warpage in the extruded or printed polymer. However, in additive manufacturing processes, the addition of fibers to the polymer printing compositions results in a printed bead that has different thermal expansion properties in the print direction, across the bead width, and through the bead thickness due to the different orientations of the fibers within the polymer matrix. In fact, the inconsistent orientation of the fibers within the polymer matrix leads to significant dissimilarities in a wide variety of mechanical and thermal properties. SUMMARY According to embodiments of the present disclosure, a polymer composition comprises a polymer matrix and a negative thermal expansion (NTE) additive, and the polymer composition is configured for additive manufacturing or extrusion. The NTE additive may comprises a powder or particulate having an average particle size of about 10 µm or smaller. In some embodiments, the NTE additive comprises a material selected from transition metal tungstates, transition metal molybdates, zirconium vanadates, zeolites exhibiting NTE, aluminum phosphates exhibiting NTE, Prussian blue analogs, antiperovskite manganese nitrides, β-eucryptite, BiNi1-xFexO3 compounds in which x is less than 1 and greater than 0, Ca2RuO4-γ, combinations thereof, hybrids thereof, and mixtures thereof. For example, in some embodiments, the NTE additive comprises one or more transition metal tungstates, one or more antiperovskite manganese nitrides, β-eucryptite, a combination thereof, a hybrid thereof, or a mixture thereof. In some embodiments, the polymer composition may also include one or more auxiliary additives. The one or more auxiliary additives may comprise one or more strengtheners, one or more magnetically receptive materials, or one or more colorants. The one or more strengtheners may comprise a material selected from the group consisting of carbon fibers, glass fibers, aramid fibers, metal fibers, metal coated fibers, and combinations thereof. According to some embodiments, the NTE additive may be present in the polymer composition in an amount of about 1 to about 60 vol% based on 100 vol% of the polymer composition. In some embodiments, a tool for use in manufacturing a composite part comprises the polymer composition after additive manufacturing or extrusion. The tool may comprise the polymer composition after extrusion and have a constant cross-section. The tool may comprise the polymer composition after additive manufacturing and have a net shape or desired net shape. According to some embodiments, a method of making a tool for use in manufacturing a composite part comprises additively manufacturing or extruding the polymer composition. In some embodiments, a method of making a composite part comprises additively manufacturing or extruding the polymer composition to form a tool, applying a composite part composition or composite part laminate on or to the tool, and exposing the tool to sufficient heat to cure the com