Method for producing a multi-layered plastics container

Claim 3

An apparatus according to Claim 1, further characterised by at least one additional die block segment formed with an accumulation reservoir and a passageway ultimately to the tubular channel (40, 211) whereby the laminate formed in the die block contains at least three layers of polymeric material.

Claim 4

An apparatus according to Claim 2, characterised by a die block segment (5, 205) formed with an accumulation reservoir (46, 219) for an adhesive polymeric layer and a third passageway (55, 220) leading into the first passageway, and an additional die block segment ( 8 , 202) formed with an accumulation reservoir (42, 224) for a second thermoplastic structural layer and a passageway (58, 225) leading therefrom into the tubular channel (40, 211) downstream of the junction of the first passageway (42, 216) with the tubular channel (40, 211), the apparatus permitting the formation of a structure comprising a thermoplastic polyolefin structural layer followed in order by an adhesive layer, an oxygen barrier layer, and a second adhesive layer and a second thermoplastic polyolefin structural layer.

Claim 5

An apparatus according to Claim 4, characterised by an additional die block segment (6, 203) formed with an accumulation reservoir (47, 221) for introducing a scrap layer into the laminate, a passageway (57, 222) leading into the tubular channel (40, 211) intermediate junctions therewith of the first passageway (42, 216) and the passageway (58, 225).

Claim 6

An apparatus according to Claim 1, characterised by a. A hollow flow tube (15, 208) having a hollow core pin (12, 209) at a delivery end portion of the apparatus; b. A segmented die block comprising an extrusion die block segment (8, 202) at the end portion of the apparatus formed with an interior surface coacting with the core pin (12, 209) to form a delivery channel (40, 212) for the flow of multiple layers of polymers, the extrusion die block segment (8) and core pin (12, 209) also defining an annular opening (23, 210) through which the multi- layer parison exits the apparatus, and c. A plurality of subextrusion die block segments located upstream of the extrusion die block segment (8) and comprising at least one principal subextrusion die block segment (7, 204) surrounding the flow tube to form therewith an annular opening forming the principal tubular channel (40) for flow of a first or structural layer of polymeric material into the delivery channel (40, 212), and at least two adjacent auxiliary subextrusion die block segments (3, 4 or 206, 207) each formed with an accumulation reservoir (44,.45 or 215, 217) and passageways leadina therefrom, there being a first passageway (42, 52; or 216) of lesser diameter than the principal tubular channel (40, 211) leading from an accumulation reservoir (44, 215) of a first of the subextrusion die block segments (3, 207) for charging with a second polymeric material from the accumulation reservoir (44, 215); the said passageways being defined between facing surfaces of adjacent subextrusion die block segments, and the first passageway (4.2, 52 or 216) leading to the principal tubular channel (40, 211), the apparatus permitting the extrusion of a laminate composed of the second and third polymeric materials which is thereafter fed from the first passageway completely around the first polymeric material in the principal tubular channel.

Claim 7

An apparatus according to Claim 5, characterised by at least one additional principal subextrusion die block segment (5, 205) formed with an accumulation reservoir (46, 219) and a third passageway (55, 220) which communicates with the first passageway and the said principal tubular channel.

Claim 8

An apparatus according to Claim 5, further characterised by an additional subextrusion die block segment (5, 205) formed with an accumulation reservoir (46, 219) for providing an adhesive polymeric layer and a third passageway (55, 220) leading into said first passageway and by principal subextrusion die block segment (8, 202) being formed with an accumulation reservoir (48, 224) for a second structural polymeric material and a passageway (58, 225) leading into the principal tubular channel (40, 211) downstream of the junction whereat the first passageway meets the principal tubular channel, the apparatus permitting formation of a parison comprising an inner thermoplastic polyolefin layer (105) followed outwardly by an adhesive layer (109), an oxygen barrier layer (107), a second adhesive layer (113) and an outer thermoplastic polyolefin layer (103).

Claim 9

An apparatus according to Claim 7, characterised by a further principal subextrusion die block segment (6, 203) formed with an accumulation reservoir (47, 221) for a polymeric scrap and a passageway (57, 222) leading into the tubular channel (40, 211) intermediate the junctions therewith of the first passageway and the passageway (58, 225) for the outer structural layer.

Claim 11

Apparatus according to Claim 9, further characterised in that the principal tubular channel (40, 211) is an annular space surrounding the mandrel (14) and defined by an opening in at least the said one principal subextrusion die block segment (7, 204) through which the mandrel (14) extends, and the said passageways leading from the accumulation reservoir of the subextrusion die block segments are tapered.

Claim 12

An apparatus according to Claim 9 or Claim 10, further characterised by means (e.g. 65) for adjusting the size of the annular opening (23, 210) through which the multilayer parison exits the apparatus.

Claim 15

A multi-layer laminate structure characterised by comprising an intermediate barrier layer (107), opposite thermoplastic polyolefin surface layers (103, 105), a first adhesive layer (109) interposed between the barrier layer (107) and a first (105) of the surface layers, a scrap layer (lll)interiorly of the said other (103) of the surface layers and a second adhesive layer (113) interposed between the scrap layer (111) and the barrier layer (107), the structure being further characterised in that the scrap layer is composed essentially of a mixture of the said thermoplastic polyolefin, adhesive and barrier layer materials.

Claim 16

A multi-layer laminate structure characterised by comprising an intermediate barrier layer (107), opposite thermoplastic polyolefin surface layers (103, 105), a first adhesive layer (109) interposed between the barrier layer (107) and a first (105) of the surface layers, a scrap layer (lll)interiorly of the said other (103) of the surface layers and a second adhesive layer (113) interposed between the scrap layer (111) and the barrier layer (107), the structure being further characterised in that the scrap layer is composed essentially of a mixture of the said thermoplastic polyolefin, adhesive and barrier layer materials.

Claim 17

A multi-layer laminate structure according to Claim 13, characterised by the polyolefin surface layers being made of polypropylene or a random copolymer of propylene and ethylene containing up to about 2 mol percent ethylene.

Claim 18

A multi-layer laminate structure according to Claim 13 or 14, characterised by the said adhesive layers being made of maleic anhydride modified polypropylene.

Claim 19

A multi-layer laminate structure according to Claims 13, 14 or 15, characterised by the said barrier layer being made of ethylene-vinyl alcohol copolymer.

Claim 20

A multi-layer laminate structure according to Claim 13, 14, 15 or 16 which is transparent and in which the thermoplastic polyolefin layers are nonoriented.

Claim 21

A multi-layer plastics container wherein the container wall is a multi-layer laminate structure according to any of claims 13 to 17.

Claim 22

A container according to claim 19, wherein the barrier layer (107) is adhesively joined to an inner of the polyolefin surface layers (105) and the scrap layer (111) is located interiorly of the outer of the polyolefin surface layers (103) and is adhesively joined to said barrier layer (107).