a film formed from a copolyme of ethylene and at least one mono-.alpha.-olefine has a combination of impact strength and stiffness which is such that the function ##EQU1## IS AT LEAST 750. The function is preferably at least 1000 and may be several thousands. The film may also have a high tear strength and good tensile strength. The copolymer from which the film is formed is preferably one in which the comonomer contains at least 5 carbon atoms; the comonomer conveniently contains not more than 12 carbon atoms. The comonomer content of the polymer is typically in the range from 6.5 up to 30%, by weight. The film can be produced by a tubular film technique using a temperature of 170.degree.-300.degree. C, a circumferential expansion of 1.2 to 10.0 times and a draw down of 2.5 to 50 times. The production of the polymeric film can include extruding the ethylene copolymer through an annular dye, maintaining the dye temperature in the range from 170.degree.-300.degree. C, blowing the exudate to give a circumferential expansion of from 1.2 up to 10.0 times and drawing the exudate to give a draw down of from 2.5 up to 50 times.

Classifications

10 codes

IPC · International Patent Classification

Section B — Performing operations; transporting

B29C48/10
B29C48/03
B29C55/28
B29C49/00
B29C55/00

Section C — Chemistry; metallurgy

C08F210/16
C08F210/00

USPC · US Patent Classification

526/350526/348264/95

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Pendency

1.2 y

421 days filing → grant

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Worldwide family

16 members · 14 offices

this patentIP5 & PCTother officessolid = grantedhover for detail · click to open

Members

DOCDB simple family 9874389

Offices

US · JP

Granted

6 of 16

grant date present

Non-English titles

shown as filed, never translated

›IP5 & PCT — 2 members

Office	Publication	Kind	Published	Filed	Status	Title
USthis patent	US-T958013-I4	I4	3 May 1977	8 Mar 1976	granted	Polymeric film
JP	JP-S51112883-A	A	5 Oct 1976	8 Mar 1976	published	Polymerized film and its manufacturing process

›Other offices — 14 members

Office	Publication	Kind	Published	Filed	Status	Title
AR	AR-225265-A1	A1	15 Mar 1982	8 Mar 1976	granted	Pelicula polimera y procedimiento para obtenerlaes
AU	AU-1177076-A	A	15 Sep 1977	8 Mar 1976	published	Polymeric film
AU	AU-496842-B2	B2	2 Nov 1978	8 Mar 1976	granted	Polymeric film
BE	BE-839326-A	A	8 Sep 1976	8 Mar 1976	published	Pellicule polymerefr
CA	CA-1077199-A	A	6 May 1980	8 Mar 1976	granted	Pellicule de polymerefr
DE	DE-2609528-A1	A1	16 Sep 1976	8 Mar 1976	published	Polymerfilmede
ES	ES-445851-A1	A1	16 May 1977	8 Mar 1976	published	Polymeric film
FR	FR-2302836-A1	A1	1 Oct 1976	8 Mar 1976	published	Film de matiere polymere olefiniquefr
FR	FR-2302836-B1	B1	24 Dec 1981	8 Mar 1976	granted	no title held
GB	GB-1532780-A	A	22 Nov 1978	7 Mar 1975	published	Polyolefine film
IN	IN-144894-B	B	22 Jul 1978	8 Mar 1976	published	no title held
IT	IT-1056944-B	B	20 Feb 1982	8 Mar 1976	granted	Film polimericiit
NL	NL-7602400-A	A	9 Sep 1976	8 Mar 1976	published	Etheencopolymeerfilm.nl
ZA	ZA-761400-B	B	23 Feb 1977	8 Mar 1976	published	Polymeric film

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