EP0205157A2 — Method of manufacturing multi-layer resin material

Claim 1

Independent Claim 79 words

A method of manufacturing a multi-layer resin material having an inner layer and an outer layer by extruding at least two different kinds of thermoplastic resins using a feed block, T-die, co-extrusion apparatus, said method comprising the step of: joining an auxiliary resin to both lateral edges of multi-layer resins within the feed block of said extruder so that the multi-layer resin material extruded from the die outlet has lateral edges which are substantially made of a single resin.

Claim 2

Independent Claim 79 words

A method of manufacturing a multi-layer resin material having an inner layer and an outer layer by extruding at least two different kinds of thermoplastic resins using a feed block, T-die, co-extrusion apparatus, said method comprising the step of: joining an auxiliary resin to both lateral edges of multi-layer resins within the feed block of said extruder so that the multi-layer resin material extruded from the die outlet has lateral edges which are substantially made of a single resin.

Claim 3

Dependent Claim 73 words

A method according to Claim 1, wherein said feed block has an input end section defined on the end thereof to which the resins are supplied and a terminating end section defined on the end thereof from which the resins are supplied to said T-die, and said auxiliary resin is supplied to the terminating end section of said feed block after said inner and outer layers have been laid up on the other.

Claim 4

Dependent Claim 20 words

A method according to Claim 1, wherein said auxiliary resin is the same as a resin for the outer layer.

Claim 5

Dependent Claim 30 words

A method according to Claim 1, wherein said auxiliary resin is a resin which has properties which are approximately the same as those of the resin for the outer layer.

Claim 6

Dependent Claim 24 words

A method according to Claim 1, wherein said auxiliary resin is supplied through the same flow path as the resin for the outer layer.

Claim 7

Independent Claim 26 words

A method according to Claim l, wherein an adhesive resin is supplied to the zone between the inner and outer layers of the multi-layer resin material.

Claim 8

Dependent Claim 38 words

A method according to Claim 1, wherein the resin for the inner layer is selected from the group consisting of ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polyvinyl chloride, polyvinyl chloride-vinylidene chloride copolymer, polyvinyl alcohol, polyamide resin and polyacrylonitrile resin.

Claim 9

Dependent Claim 27 words

A method according to Claim 1, wherein the resin for the outer layer is selected from the group consisting of polypropylene, polyethylene, ethylene-o(-olefin copolymer and mixtures thereof.

Claim 10

Dependent Claim 43 words

A method according to Claim 1, wherein at least one material selected from the group consisting of fillers, oxidation inhibitors, ultraviolet absorbers, antistatic agents, lubricants and coloring agents is added to at least one of the resins for the inner and outer layers.

Claim 11

Dependent Claim 31 words

A method according to Claim 6, wherein said adhesive resin is selected from the group consisting of ionomers and polyolefins modified with a polymerizable unsaturated carboxylic acid or a derivative thereof.

Claim 12

Dependent Claim 57 words

A method according to Claim 1, wherein said inner and outer layers are formed within said feed block into a multi-layer structure having a circular cross-section, and a resin which is practically similar to the resin for the outer layer is supplied as the auxiliary resin so that the width of the circular-shaped multi-layer structure is increased.

Claim 13

Dependent Claim 50 words

A method according to Claim 11, wherein the auxiliary resin is introduced through the same flow path as for the resin for the outer layer, and the feed rate of said auxiliary resin is controlled independently of the respective feed rates of the resins for said inner and outer layers.

Claim 14

Dependent Claim 178 words

A coextrusion process, which comprises: continuously laying u p streams of molten, first and second, different polymers to form a first continuous multi-layer structure in which said first polymer forms an intermediate middle layer and the opposite surfaces of said middle layer are covered by outer layers of said second polymer, the opposite lateral edges of said middle layer and said outer layers of said first multi-layer structure being uncovered and exposed; then continuously laying up continuous streams of molten third polymer on the opposite exposed, lateral edges of said middle and outer layers, whereby to cover said exposed edges with lateral layers of said third polymer and to form a second continuous multi-layer structure, said third polymer being identical to or compatible with said second polymer; then extruding said second continuous multi-layer structure through an extrusion die to form a sheet or film in which said middle and outer layers are of uniform thickness over the entire width of the sheet or film and said third polymer forms the lateral edge portions of the sheet or film.

Claim 15

Dependent Claim 178 words

A coextrusion process, which comprises: continuously laying u p streams of molten, first and second, different polymers to form a first continuous multi-layer structure in which said first polymer forms an intermediate middle layer and the opposite surfaces of said middle layer are covered by outer layers of said second polymer, the opposite lateral edges of said middle layer and said outer layers of said first multi-layer structure being uncovered and exposed; then continuously laying up continuous streams of molten third polymer on the opposite exposed, lateral edges of said middle and outer layers, whereby to cover said exposed edges with lateral layers of said third polymer and to form a second continuous multi-layer structure, said third polymer being identical to or compatible with said second polymer; then extruding said second continuous multi-layer structure through an extrusion die to form a sheet or film in which said middle and outer layers are of uniform thickness over the entire width of the sheet or film and said third polymer forms the lateral edge portions of the sheet or film.

Claim 16

Dependent Claim 130 words

A coextrusion process as claimed in Claim 13, in which said first and second multi-layer structures are of elliptical cross-section with said middle layer being flat in cross-section and said outer layers forming segments of arcuate cross-section which are disposed on opposite sides of said flat middle section along the major axis of the ellipse, and in said second multi-layer structure said lateral layers cover two separate portions disposed on opposite sides of the major axis of the ellipse and the remaining central regions of said outer layers are uncovered and exposed, said lateral layers being of greatest thickness in the central regions thereof which cover the lateral ends of said middle layer, the thickness of said lateral layers progressively diminishing from said central region to the opposite edges thereof.

Method of manufacturing multi-layer resin material

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