US4341827A — Biaxially oriented thermoplastic polymer film and…

Claim 1

Independent Claim 207 words

A rigid conduit comprised of a plurality of tubular-like, concentric, discrete separable layers of at least one thermoplastic crystalline polymer, each layer being a flexible film having a substantially uniform thickness within the range of 0.13 and 0.76 mm and characterized by a structure of platelet-like, discrete, generally polygonal spherulitic crystalline aggregates radially compressed and biaxially oriented in the plane of the wall of the conduit, each of the films being characterized by substantially the same density, decreased gas permeability and an increased thermal conductivity, compared to a corresponding film of the non-oriented thermoplastic crystalline polymer or of the same thermoplastic crystalline polymer which has been biaxially oriented to the same degree by conventional stretch orienting processes, a tensile impact strength at 24 C. which is at least 5 times the tensile impact strength at 24 C. of a corresponding film of the non-oriented polymer, a tensile impact strength at -45 C. which is not less than 20 percent of the tensile impact strength of 24 C. and a ratio of tensile impact strength over ultimate tensile strength which is at least 50 percent greater than such ratio determined for a corresponding film of the polymer biaxially oriented to the same degree by conventional stretch orienting processes.

Claim 2

Dependent Claim 207 words

A rigid conduit comprised of a plurality of tubular-like, concentric, discrete separable layers of at least one thermoplastic crystalline polymer, each layer being a flexible film having a substantially uniform thickness within the range of 0.13 and 0.76 mm and characterized by a structure of platelet-like, discrete, generally polygonal spherulitic crystalline aggregates radially compressed and biaxially oriented in the plane of the wall of the conduit, each of the films being characterized by substantially the same density, decreased gas permeability and an increased thermal conductivity, compared to a corresponding film of the non-oriented thermoplastic crystalline polymer or of the same thermoplastic crystalline polymer which has been biaxially oriented to the same degree by conventional stretch orienting processes, a tensile impact strength at 24 C. which is at least 5 times the tensile impact strength at 24 C. of a corresponding film of the non-oriented polymer, a tensile impact strength at -45 C. which is not less than 20 percent of the tensile impact strength of 24 C. and a ratio of tensile impact strength over ultimate tensile strength which is at least 50 percent greater than such ratio determined for a corresponding film of the polymer biaxially oriented to the same degree by conventional stretch orienting processes.

Claim 3

Dependent Claim 88 words

A method for producing the rigid conduit of claim 1, comprising: (a) preheating a preform comprised of a plurality of concentric tubular-like discrete layers of at least one thermoplastic crystalline polymer, (b) hydrostatically extruding the preform in a solid state through an extrusion zone comprising a converging wall, converging cross-section and a diverging geometry into an extrudate comprised of a plurality of concentric tubular-like discrete layers, each layer of which has a substantially uniform thickness within the range of 0.13 and 0.76 mm, and (c) cooling the extrudate.

Claim 4

Dependent Claim 12 words

The method of claim 2 including the step of slitting the extrudate.

Claim 5

Dependent Claim 16 words

The method of claim 2 wherein the layers in the preform are slit prior to preheating.

Claim 6

Dependent Claim 21 words

The method of claim 3 comprising the further step of separating the layers of the extrudate into discrete layers of film.

Claim 7

Dependent Claim 21 words

The method of claim 4 comprising the further step of separating the layers of the extrudate into discrete layers of film.

Claim 8

Dependent Claim 24 words

The method of claim 3 comprising the further step of processing the layers in the extrudate into film comprised of a plurality of layers.

Claim 9

Dependent Claim 24 words

The method of claim 4 comprising the further step of processing the layers of the extrudate into film comprised of a plurality of layers.

Claim 10

Dependent Claim 236 words

A flexible film comprised of at least one thermoplastic crystalline polymer having a substantially uniform thickness between 0.13 and 0.76 mm and characterized by a biaxially oriented structure of platelet-like, discrete, generally polygonal spherulitic crystalline aggregates compressed in a plane transverse to the plane of the film and biaxially oriented in the plane of the film and further characterized by substantially the same density, decreased gas permeability, increased thermal conductivity compared to a corresponding film of the non-oriented thermoplastic crystalline polymer or of the same thermoplastic crystalline polymer which has been biaxially oriented to the same degree by conventional stretch orienting processes, a microstructure substantially devoid of process induced microvoids and microfibrils other than those formed during melt processing, a tensile impact strength at 24 C. (75 F.) which is at least five times and an ultimate tensile strength which is at least one and three quarters that of a corresponding film of the thermoplastic crystalline polymer in an non-oriented state when tested in the plane of the film and the tensile impact strength at -45 C. (-50 F.) which is not less than 20 percent of the tensile impact strength at 24 C. (75 F.) and a ratio of tensile impact strength over ultimate tensile strength which is at least 50 percent greater than such ratio determined for a corresponding film of the polymer biaxially oriented to the same degree by conventional stretch orienting processes.

Claim 11

Dependent Claim 236 words

A flexible film comprised of at least one thermoplastic crystalline polymer having a substantially uniform thickness between 0.13 and 0.76 mm and characterized by a biaxially oriented structure of platelet-like, discrete, generally polygonal spherulitic crystalline aggregates compressed in a plane transverse to the plane of the film and biaxially oriented in the plane of the film and further characterized by substantially the same density, decreased gas permeability, increased thermal conductivity compared to a corresponding film of the non-oriented thermoplastic crystalline polymer or of the same thermoplastic crystalline polymer which has been biaxially oriented to the same degree by conventional stretch orienting processes, a microstructure substantially devoid of process induced microvoids and microfibrils other than those formed during melt processing, a tensile impact strength at 24 C. (75 F.) which is at least five times and an ultimate tensile strength which is at least one and three quarters that of a corresponding film of the thermoplastic crystalline polymer in an non-oriented state when tested in the plane of the film and the tensile impact strength at -45 C. (-50 F.) which is not less than 20 percent of the tensile impact strength at 24 C. (75 F.) and a ratio of tensile impact strength over ultimate tensile strength which is at least 50 percent greater than such ratio determined for a corresponding film of the polymer biaxially oriented to the same degree by conventional stretch orienting processes.

Claim 12

Dependent Claim 17 words

The film of claim 9 wherein the thickness of the film is between 0.38 and 0.76 mm.

Claim 13

Dependent Claim 17 words

The film of claim 9 wherein the thickness of the film is between 0.25 and 0.76 mm.

Claim 14

Dependent Claim 26 words

The film of claim 9 wherein the thermoplastic crystalline polymer contains at least 5 and not more than 80 percent of at least one particulate filler.

Claim 15

Dependent Claim 13 words

The film of claim 9 wherein the thermoplastic crystalline polymer is a polyolefin.

Claim 16

Dependent Claim 11 words

The film of claim 13 wherein the polyolefin is isotactic polypropylene.

Claim 17

Dependent Claim 12 words

The film of claim 13 wherein the polyolefin is high density polyethylene.

Claim 18

Dependent Claim 14 words

The film of claim 13 wherein the polyolefin is ultra high molecular weight polyethylene.

Claim 19

Dependent Claim 13 words

The film of claim 9 wherein the thermoplastic crystalline polymer is a polyamide.

Claim 20

Dependent Claim 11 words

The film of claim 17 wherein the polyamide is nylon 6/6.

Claim 21

Dependent Claim 11 words

The film of claim 17 wherein the polyamide is nylon 6/10.

Claim 22

Dependent Claim 11 words

The film of claim 17 wherein the polyamide is nylon 11.

Claim 23

Dependent Claim 13 words

The film of claim 9 wherein the thermoplastic crystalline polymer is a polyacetal.

Claim 24

Dependent Claim 13 words

The film of claim 9 wherein the thermoplastic crystalline polymer is a polyester.

Claim 25

Dependent Claim 13 words

The film of claim 9 wherein the thermoplastic crystalline polymer is polybutylene terephthalate.

Claim 26

Dependent Claim 13 words

The film of claim 9 wherein the thermoplastic crystalline polymer is polyvinyl alcohol.

Claim 27

Dependent Claim 10 words

The film of claim 12 wherein the filler is talc.

Claim 28

Dependent Claim 11 words

The film of claim 12 wherein the filler is calcium carbonate.

Claim 29

Dependent Claim 10 words

The film of claim 12 wherein the filler is mica.

Claim 30

Dependent Claim 97 words

A method for producing a flexible film of claim 9 comprising: (a) preheating a preform comprised of a plurality of concentric tubular-like discrete layers of at least one thermoplastic crystalline polymer, (b) hydrostatically extruding the preform in a solid state through an expansion zone comprising a converging wall, a converging cross-section and a diverging geometry, into an extrudate comprised of a plurality of concentric tubular-like discrete layers, each layer of which has a substantially uniform thickness within the range of 0.13 and 0.76 mm, (c) cooling the extrudate, and (d) separating the layers into discrete flexible films.

Claim 31

Dependent Claim 18 words

The method of claim 28 wherein the concentric layers of step (a) are interlocked at their rear portions.

Claim 32

Dependent Claim 11 words

The method of claim 28 wherein the layers are fusion welded.

Claim 33

Dependent Claim 24 words

The method of claim 28 wherein the interlocking is achieved by fabrication using a sheet folded on itself and formed into a preform shape.

Claim 34

Dependent Claim 13 words

The method of claim 28 wherein the interlocking is by a keying arrangement.

Claim 35

Dependent Claim 21 words

The method of claim 28 wherein each layer in the preform is expanded circumferentially by at least 100% in step (b).

Claim 36

Dependent Claim 16 words

The method of claim 33 wherein the circumferential expansion and the axial elongation are substantially equal.

Claim 37

Dependent Claim 28 words

The method of claim 24 wherein the extrudate of step (c) is re-extruded a plurality of times as in step (c) prior to being processed by step (d).

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1985-07-26	1986-01-25	1986-07-27	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1989-07-26	1990-01-25	1990-07-27	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1993-07-26	1994-01-25	1994-07-27	$7700.00	Window Closed / Lapsed

Biaxially oriented thermoplastic polymer film and method of manufacture

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