Extrusion of ceramic compositions and ceramic composition therefor
OwnerRodney Martin Sambrook, Wayne Austin +1inventors
InventorsRodney Martin Sambrook, Wayne Austin, Yan Yin
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Abstract
A ceramic paste composition containing a liquid carrier, ceramic particles, a binder and a dispersant additionally contains a cushioning agent so that it may be extruded at a low extrusion pressure, i.e. below about 0.04 MPa. The cushioning agent is in the form of particles which have a bulk modulus of elasticity of from about 0.1 MPa to about 4 MPa.
Claims40
A method of extruding a ceramic composition in an extruder, the method comprising extruding a paste composition comprising a liquid carrier containing particles of a ceramic material, at least one binder and at least one dispersant and a cushioning agent in the form of particles having a bulk modulus of elasticity of about 0.1 MPa to about 4 Mpa at an extrusion pressure of below about 0.04 MPa.
A method according to any preceding claim, wherein the particles are less than 2 mm in mean diameter.
A method according to any preceding claim, wherein the cushioning agent comprises hollow thermoplastic spheres.
A method according to any preceding claim, wherein the cushioning agent has a softening point above about 100° C. and a melting point which is at least 50° C. higher.
A method according to any preceding claim, wherein the particles have a density of less than 0.1 g/ml.
A method according to any preceding claim, wherein the cushioning agent is in the form of spheres having a mean diameter of 10 to 200 micron and a bulk density of 0.02 to 0.08 g/ml.
A method according to any preceding claim, wherein the cushioning agent comprises particles which are hydrophilic or have a hydrophilic coating.
A method according to any preceding claim, wherein the cushioning agent is in the form of generally isotropic particles having a modulus of elasticity in the range of about 0.1 to about 4 MPa, a dry bulk density of less than 0.6 g/ml and a softening point of at least 100° C. and a melting point which is at least 50° C. higher than the softening point.
A method of making a mouldable ceramic paste composition, the method comprising forming a substantially homogeneous mixture comprising a liquid carrier, particles of a ceramic material, a binder and a dispersant and a cushioning agent in the form of particles having a bulk modulus of elasticity of from about 0.1 MPa to about 4 MPa.
Use of a mouldable ceramic paste composition comprising a liquid carrier containing ceramic particles, at least one binder and at least one dispersant, and a cushioning agent in the form of particles having a modulus of elasticity of from about 0.1 MPa to about 4 MPa for extrusion at an extrusion pressure below about 0.04 MPa.
A mouldable ceramic paste composition comprising a liquid carrier containing:
- particles of a ceramic material
- at least one binder and at least one dispersant, and
- a cushioning agent in the form of particles having a bulk modulus of elasticity of about 0.1 MPa to about 4 MPa.
A composition according to any preceding claim, wherein the ceramic particles are less than 2 mm in mean diameter.
A composition according to any preceding claim, wherein the cushioning agent is hollow thermoplastic spheres.
A composition according to any preceding claim, wherein the cushioning agent has a softening point above about 100° C. and a melting point which is at least 50° C. higher.
A composition according to any preceding claim, wherein the particles have a density of less than 0.1 g/ml.
A composition according to any preceding claim, wherein the cushioning agent is in the form of spheres having a mean diameter of 10 to 200 micron and a bulk density of 0.02 to 0.08 g/ml.
A composition according to any preceding claim, wherein the cushioning agent comprises particles which are hydrophilic or have a hydrophilic coating.
A composition according to any preceding claim, wherein the cushioning agent is in the form of generally isotropic particles having a modulus of elasticity in the range of about 0.1 to about 4 MPa, a dry bulk density of less than 0.6 g/ml and a softening point of at least 100° C. and a melting point which is at least 50° C. higher than the softening point.
Dependencies are inferred from the claim text.