An injection molded thermoplastic preform for blow moulding to form a container, the preform base of a central part having a first, downwardly and radially inwardly tapering portion therebetween which increases in thickness from a radially outer end of the first tapering portion adjacent to the hollow transition portion to a radially inner end of the first tapering portion adjacent to the gate part and the middle part opposite the gate part can allow the injected resin to be urged back through the gate at the end of the injection moulding cycle at a lower fluid pressure in the vicinity of the gate which is associated with high resin temperatures. The technical effect achieved by the first tapering portion is that crystallinity in the gate area is minimized or eliminated, which avoids or minimizes partial blocking of the gate which would otherwise restrict the injected resin from being urged back through the gate at the end of the injection moulding cycle.
An injection moulded thermoplastic preform (2) for blow moulding to form a container, the preform (2) comprising a lower closed base portion (4), a hollow body portion (6), a hollow transition portion (8) between the lower closed base portion (4) and the hollow body portion (6), and an upper open end portion (10) adjacent to an upper part of the hollow body portion (6), wherein the closed base portion (4) comprises a central part which extends over at least 50% of an internal radius of a lower end (16, 25) of the hollow body portion (6), the central part having an external surface (109, 29, 36, 5) which comprises an outwardly raised gate (64, 68) part surrounding a central longitudinal axis of the preform (2) and a first peripheral part surrounding the gate (64, 68) part, the first peripheral part being convex and an internal surface (18, 9) which is concave and comprises a middle part opposite the gate (64, 68) part and a second peripheral part surrounding the middle part, wherein the first and second peripheral parts define a first, downwardly and radially inwardly tapering portion (15) therebetween which increases in thickness from a radially outer end (117, 17) of the first tapering portion (15, 24) adjacent to the hollow transition portion (8) to a radially inner end (119, 19) of the first tapering portion (15, 24) adjacent to the gate (64, 68) part and the middle part opposite the gate (64, 68) part, and the transition portion (8) comprises a second, upwardly and radially outwardly tapering portion (24) extending away from the central part to connect to the hollow body portion (6), the second tapering portion (15, 24) increasing in thickness from the central part to the hollow body portion (6).
B29B 11/14 - Making preforms characterised by structure or composition
B29C 45/56 - Means for plasticising or homogenising the moulding material or forcing it into the mould using mould parts movable during or after injection, e.g. injection-compression moulding
A method of forming a container, the method comprising the steps of: providing an injection moulded preform composed of a biaxially-orientable thermoplastic material, the preform being substantially planar and having a peripheral edge and a central portion; clamping at least a portion of the peripheral edge of the preform in a frame; heating the preform; stretch blow moulding the heated preform, clamped with the frame, within a mould cavity defined by a first female mould to form an intermediate article having a bottom wall and an annular sidewall beneath an upper edge clamped within the frame, the stretch blow moulding step using a stretch rod to engage an inner side of at least the central portion of the preform and axially to stretch at least a part of the central portion of the preform prior to blowing a pressurized gas against the inner side which urges the opposite side of the preform radially outwardly against the mould; and shrinking the intermediate article, clamped with the frame, onto a second male mould to form a container having a bottom wall, defining a base, and an annular sidewall, defining a body portion, beneath the upper edge clamped within the frame, the container comprising biaxially oriented thermoplastic material in the annular sidewall and at least an outer portion of the bottom wall. Also disclosed is a wide mouth container which may be formed by the method.
A container, in the form of a container body or container closure, or a lid, having a frangible weakened portion formed in a layer of polyethylene terephthalate forming a wall of the container, the weakened portion comprising a groove cut into a first surface of the layer, a first portion of the layer surrounding the groove having a crystallinity of from 35 to 45%, and a second portion of the layer, which second portion is adjacent to the first portion on opposite sides of the groove and remote from the groove, the second portion having a crystallinity at least 5% less than the crystallinity in the first portion, wherein the layer has a thickness of from 200 to 700 μm and the groove has a depth of from 200 to 500 μm.
B65D 17/28 - Rigid or semi-rigid containers specially constructed to be opened by cutting or piercing, or by tearing of frangible members or portions at lines or points of weakness
B65B 61/18 - Auxiliary devices, not otherwise provided for, for operating on sheets, blanks, webs, binding material, containers or packages for applying or incorporating package-opening or unpacking elements, e.g. tear-strips
A method of injection moulding an article, the method comprising the steps of: (a) providing an injection mould comprising a plurality of mould parts defining a mould cavity of the injection mould, the plurality of mould parts including first and second movable mould parts, the injection mould further comprising an injection inlet for injecting molten thermoplastic resin material into the mould cavity, wherein the injection inlet is located in the vicinity of the first movable mould part and the second movable mould part is remote from the injection inlet; (b) disposing the first and second movable mould parts in a first configuration so as to define a first intermediate moulding cavity, in which first configuration the first movable mould part is in a first rearward position and the second movable mould part is in a first forward position; (c) injecting molten thermoplastic resin material into the first intermediate moulding cavity through the injection inlet to fill the first intermediate moulding cavity with the molten material; (d) closing the injection inlet; (e) after commencement of the injecting step and at least partly after the closing step, moving the second movable mould part from the first forward position to a second rearward position; (f) moving the first movable mould part from the first rearward position to a second forward position; and (g) moving the second movable mould part from the second rearward position to a third forward position thereby to dispose the first and second movable mould parts in a final configuration so as to define a final moulding cavity of the injection mould filled with the molten material, the final moulding cavity defining a cavity outer surface which defines the outer shape of the article to be moulded.
B29C 51/02 - Combined thermoforming and manufacture of the preform
B29C 45/56 - Means for plasticising or homogenising the moulding material or forcing it into the mould using mould parts movable during or after injection, e.g. injection-compression moulding
A method of forming a container, the method comprising the steps of: providing an injection moulded preform composed of a biaxially-orientable thermoplastic material, the preform being substantially planar and having a peripheral edge and a central portion; clamping at least a portion of the peripheral edge of the preform in a frame; heating the preform; stretch blow moulding the heated preform, clamped with the frame, within a mould cavity defined by a first female mould to form an intermediate article having a bottom wall and an annular sidewall beneath an upper edge clamped within the frame, the stretch blow moulding step using a stretch rod to engage an inner side of at least the central portion of the preform and axially to stretch at least a part of the central portion of the preform prior to blowing a pressurized gas against the inner side which urges the opposite side of the preform radially outwardly against the mould; and shrinking the intermediate article, clamped with the frame, onto a second male mould to form a container having a bottom wall, defining a base, and an annular sidewall, defining a body portion, beneath the upper edge clamped within the frame, the container comprising biaxially oriented thermoplastic material in the annular sidewall and at least an outer portion of the bottom wall. Also disclosed is a wide mouth container which may be formed by the method.
An injection moulded thermoplastic preform for blow moulding to form a container, the preform comprising a lower closed base portion, a hollow body portion, a hollow transition portion between the lower closed base portion and the hollow body portion, and an upper open end portion adjacent to an upper part of the hollow body portion, wherein the closed base portion comprises a central portion which extends over at least 50% of an internal radius of a lower end of the hollow body portion and is either substantially flat or has a shallow concave or convex internal curvature, and the transition portion comprises an upwardly and radially outwardly tapering portion extending away from the central portion to connect to the hollow body portion, the tapering portion being inclined at an angle of from 1 to 20 degrees to a longitudinal axis of the preform and the tapering portion increasing in thickness from the central portion to the hollow body portion. Also disclosed is a method of injection moulding the thermoplastic preform.
B29C 45/56 - Means for plasticising or homogenising the moulding material or forcing it into the mould using mould parts movable during or after injection, e.g. injection-compression moulding
A container comprising a part, in the form of a container body or container closure, optionally a lid, having a frangible weakened portion formed in a layer of polyethylene terephthalate forming a wall of the container, the weakened portion comprising a groove (20) cut into a first surface of the layer, a first portion (24) of the layer surrounding the groove having a crystallinity of from 35 to 45%, and a second portion (26) of the layer, which second portion is adjacent to the first portion on opposite sides of the groove and remote from the groove, the second portion having a crystallinity at least 5% less than the crystallinity in the first portion, wherein the layer has a thickness of from 200 to 700 11 m and the groove has a depth of from 200 to 500 11 m.
A method of forming a blow molded container in the form of a tub, the method comprising the steps of: providing an injection molded preform composed of a biaxially-orientable thermoplastic material, the preform being substantially planar; heating the preform; and stretch blow molding the heated preform within a mold cavity to form a tub having a bottom wall and an annular sidewall having an upper edge, the tub comprising biaxially oriented thermoplastic material in the annular sidewall and at least an outer portion of the bottom wall, the stretch blow molding step using at least one stretch rod to engage an inner side of the preform and axially to stretch at least a part of the preform prior to blowing a pressurized gas against the inner side which urges the opposite side of the preform radially outwardly against the mold.
A method of injection moulding an article, the method comprising the steps of: (a) providing an injection mould comprising a plurality of mould parts defining a mould cavity of the injection mould, the plurality of mould parts including first and second movable mould parts, the injection mould further comprising an injection inlet for injecting molten thermoplastic resin material into the mould cavity, wherein the injection inlet is located in the vicinity of the first movable mould part and the second movable mould part is remote from the injection inlet; (b) disposing the first and second movable mould parts in a first configuration so as to define a first intermediate moulding cavity, in which first configuration the first movable mould part is in a first rearward position and the second movable mould part is in a first forward position; (c) injecting molten thermoplastic resin material into the first intermediate moulding cavity through the injection inlet to fill the first intermediate moulding cavity with the molten material; (d) closing the injection inlet; (e) after commencement of the injecting step and at least partly after the closing step, moving the second movable mould part from the first forward position to a second rearward position; (f) moving the first movable mould part from the first rearward position to a second forward position; and (g) moving the second movable mould part from the second rearward position to a third forward position thereby to dispose the first and second movable mould parts in a final configuration so as to define a final moulding cavity of the injection mould filled with the molten material, the final moulding cavity defining a cavity outer surface which defines the outer shape of the article to be moulded.
B29C 45/56 - Means for plasticising or homogenising the moulding material or forcing it into the mould using mould parts movable during or after injection, e.g. injection-compression moulding
Blow Moulded Container and Manufacture Thereof A method of forming a blow moulded container in the form of a tub, the method comprising the steps of: providing an injection moulded preform (2) composed of a biaxially-orientable thermoplastic material, the preform being substantially planar; heating the preform; and stretch blow moulding the heated preform within a mould cavity to form a tub having a bottom wall and an annular sidewall having an upper edge, the tub comprising biaxially oriented thermoplastic material in the annular sidewall and at least an outer portion of the bottom wall, the stretch blow moulding step using at least one stretch rod (12) to engage an inner side of the preform and axially to stretch at least a part of the preform prior to blowing a pressurized gas against the inner side which urges the opposite side of the preform radially outwardly against the mould.
B29C 51/14 - Shaping by thermoforming, e.g. shaping sheets in matched moulds or by deep-drawingApparatus therefor using multilayered preforms or sheets
B29C 51/04 - Combined thermoforming and prestretching, e.g. biaxial stretching
B29C 51/06 - Combined thermoforming and prestretching, e.g. biaxial stretching using pressure difference
An injection moulded thermoplastic preform (102) for blow moulding to form a container, the preform comprising a lower closed base portion (104), a hollow body portion (106), a hollow transition portion between the lower closed base portion and the hollow body portion, and an upper open end portion adjacent to an upper part of the hollow body portion, wherein the closed base portion comprises a central portion (114) which extends over at least 50% of an internal radius of a lower end of the hollow body portion and is either substantially flat or has a shallow concave or convex internal curvature, and the transition portion comprises an upwardly and radially outwardly tapering portion extending away from the central portion to connect to the hollow body portion, the tapering portion being inclined at an angle of from 1 to 20 degrees to a longitudinal axis of the preform and the tapering portion increasing in thickness from the central portion to the hollow body portion. Also disclosed is a method of injection moulding the thermoplastic preform.
B29B 11/14 - Making preforms characterised by structure or composition
B29C 45/56 - Means for plasticising or homogenising the moulding material or forcing it into the mould using mould parts movable during or after injection, e.g. injection-compression moulding
13.
APPARATUS FOR CONDITIONING PREFORMS AND METHOD USING IT
An apparatus (2) for reheating and conditioning an elongate preform (50) for forming a blow moulded container, said apparatus (2) comprising: a receiver (4) including an elongate annular non - cylindrical inner surface portion (13), wherein the surface portion (13) defines a cavity (8) and is adapted to engage with an elongate outer surface (68) of an elongate preform (50) to transfer heat thereto by conduction from said surface portion (13), wherein the surface portion (13) includes a three-dimensional relief (100) to provide substantially non-uniform contact between the receiver (4) and the elongate preform (50); and means (20, 22) for heating said receiver (4).
An injection moulded thermoplastic preform (102) for blow moulding to form a container, the preform comprising a lower closed base portion (104), a hollow body portion (106), a hollow transition portion between the lower closed base portion and the hollow body portion, and an upper open end portion adjacent to an upper part of the hollow body portion, wherein the closed base portion comprises a central portion (114) which extends over at least 50% of an internal radius of a lower end of the hollow body portion and is either substantially flat or has a shallow concave or convex internal curvature, and the transition portion comprises an upwardly and radially outwardly tapering portion extending away from the central portion to connect to the hollow body portion, the tapering portion being inclined at an angle of from 1 to 20 degrees to a longitudinal axis of the preform and the tapering portion increasing in thickness from the central portion to the hollow body portion. Also disclosed is a method of injection moulding the thermoplastic preform.
B29B 11/14 - Making preforms characterised by structure or composition
B29C 45/56 - Means for plasticising or homogenising the moulding material or forcing it into the mould using mould parts movable during or after injection, e.g. injection-compression moulding
There is provided an injection moulded thermoplastic preform for blow moulding to form a container. There is also provided a method of injection moulding a thermoplastic preform for blow moulding to form a container. Technical problems with prior art injection moulded thermoplastic preforms include back-flow of injected thermoplastic material through a gate of the mould, which may cause blocking of the gate when the thermoplastic material solidifies. This may also prevent the preform from being injection moulded to the desired dimensions. According to the invention there is provided an injection moulded thermoplastic preform, and a method of producing such a preform, where a geometry of a base portion of the preform mitigates or overcomes these problems.
B29C 45/56 - Means for plasticising or homogenising the moulding material or forcing it into the mould using mould parts movable during or after injection, e.g. injection-compression moulding
B29C 49/00 - Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mouldApparatus therefor
B29C 49/02 - Combined blow-moulding and manufacture of the preform or the parison
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