AU617714B2 - Film extrusion of polyamides - Google Patents
Film extrusion of polyamides Download PDFInfo
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- AU617714B2 AU617714B2 AU25700/88A AU2570088A AU617714B2 AU 617714 B2 AU617714 B2 AU 617714B2 AU 25700/88 A AU25700/88 A AU 25700/88A AU 2570088 A AU2570088 A AU 2570088A AU 617714 B2 AU617714 B2 AU 617714B2
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- polyamide
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Description
i 1 COMMONWEALTH OF AUSLI 'P 1 4 The Patents Act 1952-1969 Name of Applicant(s): TRANSPAK INDUSTRIES LIMITED Address of Applicant(s): 23-25 PORANA ROAD,
GLENFIELD,
AUCKLAND,
NEW ZEALAND A Ar ;1r t A A Actual Inventor(s): Address for Service: JOHN CAMERON SADLER GREGORY ROY STEWART G.R. CULLEN COMPANY, Patent Trade Mark Attorneys, Dalgety House, 79 Eagle Street, Brisbane, Qld. 4000, Australia.
I t t tI COMPLETE SPECIFICATION FOR THE INVENTION ENTITLED: "FILM EXTRUSION OF POLYAMIDES" The following statement is a full description of the invention including the best method of performing it known to us:- I ~c -2- This invention relates to a film extrusion and more particularly to a film extrusion containing amorphous and highly crystalline polyamides.
Film extruded from polyamides (which are commonly referred to as nylons) is often used in packaging of products, particularly products which have a limited shelf life, such as foodstuffs and the like. These films are usually multilayer in structure, with at least one of the layers being formed from a polymer of ethylene. Polyamides most commonly used in the forming of such films are aliphatic polyamides, such as nylon 66 and nylon 6. These polymers are produced from polymerisation of hexamethylenediamine and 1 adipic acid or caprolactam. These polymers tend to be highly crystalline when formed into film by, for example, a tubular blown film process. A °disadvantage caused by such crystallinity is that the film is not readily heat formed, by a thermoforming process. A further disadvantage is that the film has a relatively poor optical clarity, detracting from the suitable presentation of products packaged in such film. On the other hand, the use of aliphatic nylons in such films does have some certain advantages. These advantages include high gas barrier properties and resistance to flex-cracking in flexible film applications. Film formed from aliphatic nylons is hygroscopic, and although the film is highly impermeable to gaseous permeants when dry, the film becomes relatively less impermeable when wet. In order to overcome the thermoformability problem, aliphatic nylons of lower crystallinity have been used. These nylons include nylon 11 and nylon 6-66 copolymer. Although film formed of such nylons has good thermoformability characteristics, such films also exhibit a higher gas permeability than the more crystalline forms, such as nylon 6 and nylon 66. In order to overcome these problems, amorphous nylons could be used. These nylons exhibit virtually no crystallinity when formed into films, and are available as aromatic nylons.
-3- An amorphous aromatic nylon polymer may be formed, for example, from the polymerisation of phthalic acid and hexamethylenediamine. Film formed from amorphous nylons shows good thermoformability and optical clarity.
However, such film is very brittle and prone to failure by flex-cracking, in flexible film applications. One advantage of such film, however, is that the film is also hygroscopic, but becomes more impermeable to gaseous permeants when wet, rather than less impermeable as is the case with aliphatic nylons. It has now been found that a polyamide-containing film can be formed comprising a combination of amorphous polyamide and highly crystalline polyamides, the film thus formed having 10 improved gas impermeability characteristics, and enhanced optical clarity and Sthermoformability.
It is an object therefore of one aspect of the present invention to provide a polyamide-containing film which exhibits properties which overcome or minimise the abovementioned problems.
Further objects of the invention will become apparent from the following description.
According to one aspect of the present invention there is provided a film containing at least one layer of a polyamide mixture, said mixture including at least one highly crystalline polyamide and at least one amorphous polyamide, wherein the highly crystalline polyamide content ranges from 35 to 85 percent by weight of the total polyamide content, and wherein the amorphous polyamide content ranges from to 65 percent by weight of the total polyamide content.
According to a further aspect of the present invention there is provided a polyamide-containing film of at least two layers, wherein at least one of said layers is formed of at least one highly crystalline polyamide, and at least a further layer of said film is formed of at least one amorphous polyamide, the ratio of highly crystalline polyamide to amorphous polyamide in said film being in the range 35 to percent by weight of the total polyamide content to 15 to 65 percent by weight of the total polyamide content.
-4 According to a still further aspect of the present invention there is provided a method of forming a polyamide-containing film including the steps of mixing together at least one highly crystalline polyamide and at least one amorphous polyamide, feeding said polyamides into a extruder, melting said polyamides and extruding the resulting molten polymer in the form of a film; wherein the highly crystalline polyamide content is in the range of 35 to 85 percent by weight of the total polyamide content and wherein the amorphous polyamide content is in the range 15 to 65 percent by weight of the total polyamide content.
According to a still further aspect of the present invention there is provided a I' t 10 method of forming a polyamide-containing film including the steps of extruding at S*least one layer of highly crystalline polyamide and extruding at least one further layer of amorphous polyamide, and thereafter combining said layers into a film; wherein the highly crystalline polyamide content is in the range 35 to 85 percent by weight the total polyamide content and wherein the amorphous polyamide content is in the range 15 to 65 percent by weight of the total polyamide content.
According to a still further aspect of the present invention there is provided a polyamide-containing film as described above, wherein the amorphous polyamide is an amorphous aromatic polyamide.
According to a still further aspect of the present invention there is provided a method of forming a polyamide-containing film, wherein the amorphous polyamide is an amorphous aromatic polyamide.
According to a still further aspect of the present invention there is provided a polyamide-containing film as described above, wherein said highly crystalline polyamide is a highly crystalline aliphatic polyamide.
According to a still further aspect of the present invention there is provided a method as described above, wherein the highly crystalline polyamide is a highly crystalline aliphatic polyamide.
Further aspects of the present invention will become apparent from the following description, which is given by way of example only.
As discussed above, the method according to the present invention provides a polyamide-containing film suitable for use in packaging and the like, which comprises a combination of highly crystalline polyamide and amorphous polyamide.
In one preferred form of the invention the amorphous polyamide is an amorphous aromatic polyamide. In one preferred form of the invention the highly crystalline polyamide is a highly crystalline aliphatic polyamide. The resulting film has improved gas impermeability, acceptable optical clarity and thermoformability.
The term "highly crystalline polyamide" when used herein, in the specification and claims, is defined as a polyamide with a sharply defined melting temperature or 10 narrow melting range. Such highly crystalline polyamides are also known to those skilled in the art simply as "crystalline polyamides" or as "semi-crystalline polyamides".
The term "amorphous polyamide" when used herein, in the specification and claims, is defined as a polyamide with an undefined melting temperature, or one which goes through a gradual transition from solid to liquid as its temperature is raised.
It should be appreciated that where reference is made herein to an amorphous polyamide, any suitable amorphous polyamide may be used. Amorphous aromatic polyamides are particularly preferred, but the scope of the invention is not intended to be limited to amorphous aromatic polyamides.
It should be appreciated that where reference is made herein to a highly crystalline polyamide, any suitable highly crystalline polyamide may be used. Highly crystalline aliphatic polyamides are particularly preferred, however the scope of the invention is not intended to be limited to highly crystalline aliphatic polyamides.
Description is generally given herein with reference to films, and extrusion of films. A film is preferably be defined as a thin sheet, up to Imm in thickness.
4 -6- *94 9* 94 9 9 999 9 The film may be composed of one or several layers, and may be manufactured by simultaneous extrusion of the different material layers, or by fabricating the layers separately, and then laminating them together to form the final film.
In one form of the invention, the film is formed using a tubular blown film process. Other extrusion techniques may also be used to advantage, however it should be appreciated that techniques other than extrusion techniques may be used.
For example, a lamination process may be used.
In one preferred form of the invention, the film is formed by feeding a mixture of highly crystalline polyamide and amorphous polyamide into an extruder, 10 melting the mixture, and extruding the molten polymer in the form of a film.
In another form of the invention however, separate layers of highly S crystalline aliphatic polyamide and amorphous polyamide are extruded, and thereafter formed into a single film.
In one preferred form of the invention, a film may be formed of multiple layers of polyamide. More than one highly crystalline aliphatic polyamide and more than one amorphous aromatic polyamide may be used in the formation of a single film. For example, the following combinations would be examples which fall within the scope of the invention: One or more layers of highly crystalline aliphatic polyamide may be combined with one or more layers of amorphous aromatic polyamide (ii) one or more layers of highly crystalline aliphatic polyamide-amorphous aromatic polyamide blend combined with one or more layers of amorphous aromatic polyamide, and (iii) one or more layers of highly crystalline aliphatic polyamide-amorphous aromatic polyamide blend combined with one or more layers of highly crystalline aliphatic polyamide.
-7 The highly crystalline polyamide content is in the range of 35 to 85 percent by weight of the total polyamide content and the amorphous polyamide content is in the range of 15 to 65 percent by weight of the total polyamide content.
The preferred highly crystalline polyamide content is in the range of 50-80 percent by weight of the total polyamide content. The preferred amorphous polyamide content is in the range of 20 to 50 percent by weight of the total polyamide content.
Examples of the preparation of film of the present invention, and properties thereof, are given below. Percentages hereinafter referred to are by weight of the '0".10 total polyamide content composed of highly crystalline or amorphous polyamide.
it EXAMPLE 1 Multi-layer tubular blown films were manufactured by a 5-layer co-extrusion system. Overall film thickness was maintained at 125 microns, with 65 microns of nylon distributed between 2 layers. The remaining 60 microns of the structure was Scomposed of polymers of ethylene. Trials were performed in which the nylon layers were varied in composition while all other film parameters remained constant.
In trial 1, particles of nylon 6-66 copolymer (Novamid 2030, manufactured by 0 Mitsubishi Chemical Company; melting temperature 198 C) were melted and extruded into the 2 nylon layers at the ratio of 52 microns in one of the layers, and 13 microns in the other layer. A sample of the resulting 125 micron film was collected for testing. In trial 2, the process was repeated, this time with a nylon 6 homopolymer (Novamid 1030, manufactured by Mitsubishi Chemical Company; melting temperature 224 0
C).
In trial 3, a physical mixture of nylon particles was extruded into the layers, comprising 91 percent by weight of nylon 6 homopolymer and 9 percent by weight of an amorphous, aromatic nylon manufactured from the polymerization of hexamethylenediamine and phthalic acid (Selar PA 3426, manufactured by E.I.
DuPont de Nemours Co).
I
7 -8- In trial 4, the blend ratio was 87 percent nylon 6 homopolymer and 13 percent of the same amorphous nylon. In trial 5, 83 percent nylon 6 homopolymer and and 17 percent amorphous nylon were used. In all trials, the layer ratios and extrusion condition were held constant.
Table I lists the trial conditions, and measurement results on the films produced. The thermoformability of the films was rated on a subjective appearance basis, based on the film's ability to hold a formed shape and to maintain an even thickness profile. The film of trial 5 showed the best combination of optical clarity, oxygen barrier, and thermoformability.
TABLE 1 FILM PROPFRTIES Example 1 C ti t I C Trial Nylon Blend No.
1 100% Nylon 6-66 copolymer 2 100% Nylon 6 Homopolymer 3 91% Nylon 6 Homopolymer, 9% amorphous nylon 4 87% Nylon 6 Homopolymer, 13% Amorphous Nylon 83% Nylon 6 Homopolymer, 17% Amorphous Nylon Optical Clarity haze) Oxygen Transmission 2 (cc/m 2 /24hr) 24.6 27.6 25.7 23.8 18.4 Good Unacceptable Unacceptable Thermoformability 3 Fair Good I. Measured by ASTM method D1003 61 2. Measured at 250C, 93% relative humidity on Mocon 100 Oxtran 3. Film heated to 900C, and vacuum drawn into a 100mm diameter by depth form.
S-9- EXAMPLE 2 Multi-layer tubular blown films were manufactured by a 5-layer co-extrusion system. The films were all made with two layers of nylon polymer on one side of the film, and a layer of ethylene polymer on the other side.
Trials were performed oy maintaining the middle layer of nylon as a pure copolymer of nylon 6 and nylon 66 (Novamid 2030) and by varying the outer nylon layer to either of the same copolymer, or to an amorphous aromatic nylon manufactured from the polymerization of phthalic acid and hexamethylenediamine (Selar PA 3426).
Table 2 lists the four trials run in the series. Trials I and 2 produced 100 micron thick film, with a constant middle layer of 42 microns of the nylon 6-66 copolymer.
Trial I incorporated a 10 micron outside layer of the same copolymer, and r t trial 2 used a 10 micron outside 'ayer of the amorphous aromatic nylon. In trials 3 and 4, the overall film thickness was maintained at 65 microns, with the same S.i. overall nylon layer percentages as in trials I and 2.
TABLE 2 FILK COM~POSITIONS Example 2 Trial Overall Thickness (microns)
MIDDLE
Component
LAYER
Thickness (microns) OUTSIDE L-AYER component Thickness (microns) PERCENT BY WEIGHT OF TOTAL POLYAMIDE Highly Crystalline Amorphous Polyamide Polyamide 1 100 2 100 3 65 4 65 Nylon 6-66 42 Copolymer Nylon 6-66 42 Copolymer Nylon 6-66 10 Copolymer Amorphous Nylon Nylon 6-66 6.5 Copolymer Amorphous Nylon 100% Nylon 6-66 Copolymer 100% Nylon 6-66 27 Copolymer I i
B
r i i i i The optical clarity and oxygen transmission rates of the films produced in trials I to 4 were measured, and the results reported in table 3. It is seen that the films containing the outside layer of amorphous nylon showed superior optical clarity and lower oxygen transmission values than the same thickness of films with the outside layer composed of the nylon 6-66 copolymer.
It is observed that as the relative humidity increased from 75 percent to 93 percent at 25 C, the samples containing the amorphous nylon showed a larger oxygen barrier improvement over those without the amorphous nylon.
r 9 t i C1 Trial No.
TABLE 3 FILM PROPERTIES Example 2 Optical Properties Oxygen Transmission (cc/m2/24hr) at 25 C %Gloss
I
%Haze 2 75%RH 93%RH 1 2 3 4 1.
2.
3.
ASTM method 02457.
ASTM method D10003-61.
Measured with Mocon 100 Oxtran device.
Film samples were conditioned over salt solutions to equilibrium at the and 93% relative humidity levels.
-l- In a subsequent product application test, films from trials I to 4 were used to fabricate commercial thermoformed packages for packaging fresh meat. To make the packages, the 100 micron films from trials I and 2 were heated to C, and drawn by vacuum into a thermoform mould. The 65 micron films from trials 3 and 4 were then sealed as top layers to the thermoformed bottom layers, 2 resulting in a final package surface area of 0.04m Package A was formed with a thermoformed bottom web from trial I sealed to a top web from trial 3.
Package B was formed with a thermoformed bottom web from trial 2, sealed to a top web from trial 4.
t(f< ,10 Table 4 summarizes the packages made, and compares the critical properties of package thickness and permeability to oxygen. The layer of j M amorphous nylon in package B makes the thermoformed film draw down much more evenly then the film without the amorphous nylon in package A. The result is a thicker overall package and greatly improved barrier to oxygen of package B over package A.
TABLE 4 PACKAGE PROPERTIES Example 2 Package Nylon Composition Minimum average Package oxygen thermoformed film transmission rate thickness (microns) (cc/m /24hr) i 20 A 1 layers of nylon 34 42 B 1 layer nylon 6-66 52 22 copolymer I layer amorphous (aromatic) nylon 1. Measure with Mocon 100 Oxtran device, the packages conditioned to 250C, over an aqueous salt solution.
12- EXAMPLE 3 Multi-layer tubular blown films were manufactured using a five layer co-extrusion system. Films were made to 125 microns overall thickness, with a middle layer of 35 microns of nylon, the remaining layers being polymers of ethylene. Trials were performed varying the nylon composition of the middle layer, by extruding to that layer blends of a nylon 6 homopolymer (Durethan B38F manufactured by Bayer; melting temperature 217-221 C) and an amorphous nylon (Selar PA 3426). Table 5 summarizes the compositions used, and the resistance of the resulting films to failure by flex-cracking. Trials I and 5 were 10 run as controls, using only the pure nylon in the middle layer. In trials 2, 3 and 4, physical admixtures of the nylon granules were fed to an extruder, melted, and extruded into the film's middle layer.
The results of the Gelbo Flex Test can only be interpreted from experience with the performance of actual packages. From experience, it has been found that an oxygen barrier film for most flexible packaging applications should be resistant to at least 500 Gelbro flexing cycles before pinholing and loss of barrier. Using this criterion, the films of trials 4 and 5 with more than amorphous nylon, would be classed as unacceptable. The films of trials 1, 2 and I 3 would be acceptable.
i 13- TABLE 5 FLEX-CRACK RESISTANCE Example 3 Trial No.
1 2 ttf I t( 4r I IC *C IE tI It $t f C CC C Sr oa C C *C Composition of Nylon layer 100% nylon 6 75% nylon 6 25% amorphous nylon 50% nylon 6 50% amorphous nylon 25% nylon 6 amorphous nylon 100% amorphous nylon Flex-crack resistance (No. of cycles to failure) More than 1000 More than 1000 720 360 Measured by Gelbo Flex Tester; failure determined by a marked increase in oxygen transmission rate. Films were conditioned at 23 0 C, 93% R.H. before flex testing.
r 1 14- In the examples given above, each film was formed by simultaneous extrusion of the nylon and other layers.
It should also be appreciated that variations and modifications may be made to the invention, without departing from the scope thereof. For example, although examples have been given of a 5-layer co-extrusion system, other systems may also be used, such as lamination or 3-layer co-extrusion.
Other compounds and components may also be used in forming a film according to the present invention. For example, ethylene polymer layers may be included in a film of the present invention.
The inclusion of the ethylene polymer has advantages in so far as heat sealability and water vapour barrier properties is concerned. Furthermore, layers of varying thicknesses may also be used to advantage.
Improved properties of gas impermeability and in particular impermeability to carbon dioxide, increase the shelf life of products such as foodstuffs and the like, packaged in film of the present invention. A measured improvement in oxygen 2 T impermeability will also indicate an improvement in the impermeability to other S.t gases, such as carbon dioxide.
The improved optical clarity al3so allows for improved presentation of products tpackaged in such film.
20 Thus it will be appreciated from the examples above that by the present invention there is provided a film extrusion and method of forming the same which provides for a polyamide film which has improved properties of optical clarity, thermoformability and gas impermeability.
Although the present invention has been described by way of example, and with particular reference to various embodiments thereof, it should be appreciated that variations and modifications may be made thereto, without departing from the scope thereof, as defined in the appended claims.
Claims (13)
1. A film containing at least one layer of a polyamide mixture, said mixture including at least one highly crystalline polyamide and at least one amorphous polyamide, wherein the highly crystalline polyamide content ranges from 35 to percent by weight of the total polyamide content, and wherein the amorphous polyamide content ranges from 15 to 65 percent by weight of the total polyamide content.
2. A polyamide-containing film of at least two layers, wherein at least one of said layers is formed of at least one highly crystalline polyamide, and at least a further layer of said film is formed of at least one amorphous polyamide, the ratio of highly crystalline polyamide to amorphous polyamide in said film being in the range 35 to 85 percent by weight of the total polyamide content to 15 to percent by weight of the total polyamide content.
3. A film as claimed in claim 1 or claim 2, wherein the highly crystalline polyamide content ranges from 50 to 80 percent by weight of the total polyamide content.
4. A film as claimed in any one of the preceding claims, wherein the amorphous polyamide content ranges from 20 to 50 percent by weight of the total polyamide content.
5. A film as claimed in any one of the preceding claims, wherein said amorphous polyamide is an amorphous aromatic polyamide.
6. A film as claimed in any one of the preceding claims, wherein said highly crystalline polyamide is a highly crystalline aliphatic polyamide. I I 16 rn~* o r ~r Ir~r D o cr* O Y fl
7. A film as claimed in claim 6 when dependent on claim 5 and wherein one or more layers of said highly crystalline aliphatic polyamide are combined with one or more layers of said amorphous aromatic polyamide.
8. A film as claimed in claim 6 when dependent on claim 5 and including one or more layers of highly crystalline aliphatic polyamide-amorphous aromatic polyamide blend, combined with one or more layers of amorphous aromatic polyamide.
9. A film as claimed in claim 6 when dependent on claim 5 and including one or more layers of highly crystalline aliphatic polyamide-amorphous aromatic polyamide blend combined with one or more layers of highly crystalline aliphatic polyamide. A method of forming a polyamide-containing film including the steps of mixing together at least one highly crystalline polyamide and at least one amorphous polyamide, feeding said polyamides into an extruder, melting said polyamides and extruding the resulting molten polymer in the form of a film; wherein the highly crystalline polyamide content is in the range of 35 to 85 percent by weight of the total polyamide content and wherein the amorphous polyamide content is in the range 15 to 65 percent by weight of the total polyamide content. 17
11. A method of forming a polyamide-containing film including the steps of extruding at least one layer of highly crystalline polyamide and extruding at least one further layer of amorphous polyamide, and thereafter combining said layers into a film, wherein the highly crystalline polyamide content is in the range 35 to 85 percent by weight of 'the total polyamide content and wherein the amorphous polyamide content is in the range 15 to 65 percent by weight of the total polyamide content. r0. 12. A method as claimed in claim 10 or claim 11, used 0 •to form a film as claimed in any one of the preceding claims 3 to 6.
13. A film as claimed in claim 1 or claim 2, 99*00 substantially as described with reference to the 9009 embodiments of the invention in any one of the o 0 examples 1 to 3.
14. A method of forming a polyamide film as claimed in claim 10 or claim 11 substantially as described with reference to the embodiments of the invention in any one of the examples 1 to 3. A method of forming a polyamide film as claimed in any one of claims 10, 12 and 14 substantially as hereinbefore described.
16. A film as claimed in any one of claims 1 to 9 and 13, substantially as hereinbefore described. DATED this Seventeenth day of September, 1991. TRANSPAK INDUSTRIES LIMITED by their Patent Attorneys CULLEN CO.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NZ22263287A NZ222632A (en) | 1987-11-20 | 1987-11-20 | Films comprising semi-crystalline polyamide and amorphous polyamide either as a blend or in a multi-layer film having at least one layer each of semi-crystalline and amorphous polyamide |
| NZ222632 | 1987-11-20 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU2570088A AU2570088A (en) | 1989-05-25 |
| AU617714B2 true AU617714B2 (en) | 1991-12-05 |
Family
ID=19922289
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU25700/88A Withdrawn - After Issue AU617714B2 (en) | 1987-11-20 | 1988-11-18 | Film extrusion of polyamides |
Country Status (2)
| Country | Link |
|---|---|
| AU (1) | AU617714B2 (en) |
| NZ (1) | NZ222632A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU643035B2 (en) * | 1990-06-27 | 1993-11-04 | Gunze Limited | Multi-layer films and process for prepartion thereof |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE69119982T2 (en) * | 1990-06-27 | 1996-10-24 | Gunze Kk | Multilayer film and process for its manufacture |
| US6203750B1 (en) | 1992-06-05 | 2001-03-20 | Cryovac, Inc | Method for making a heat-shrinkable film containing a layer of crystalline polyamides |
| US5534277A (en) * | 1994-12-09 | 1996-07-09 | W. R. Grace & Co.-Conn. | Film for cook-in applications with plural layers of nylon blends |
| DK0755777T3 (en) * | 1995-06-29 | 2002-02-04 | Wipak Walsrode Gmbh & Co Kg | Slidable, sealable multilayer foil with enhanced depth-drawing capability based on polyamide and polyolefins |
| EP0755778A1 (en) | 1995-07-28 | 1997-01-29 | Wolff Walsrode Ag | Sterilisable barrier film based on polyamides and polyolefins |
| US5763095A (en) * | 1995-11-29 | 1998-06-09 | W. R. Grace & Co.-Conn. | Breathable film for cheese packaging |
| US6040392A (en) * | 1998-03-10 | 2000-03-21 | Alliedsignal Inc. | Nylon 6 or 66 based compositions and films formed therefrom having reduced curl |
| WO2001015900A1 (en) * | 1999-08-27 | 2001-03-08 | Toray Industries, Inc. | Laminated film and vapor deposition film using the same |
| US6379812B1 (en) | 2000-05-31 | 2002-04-30 | Cryovac, Inc. | High modulus, multilayer film |
| US6984442B2 (en) | 2002-07-19 | 2006-01-10 | Cryovac, Inc. | Multilayer film comprising an amorphous polymer |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU592037B2 (en) * | 1987-02-05 | 1989-12-21 | Kureha Kagaku Kogyo Kabushiki Kaisha | Polyamide based films and laminates |
| AU602203B2 (en) * | 1987-03-26 | 1990-10-04 | E.I. Du Pont De Nemours And Company | Multi-layer plastic container |
| AU605051B2 (en) * | 1988-11-09 | 1991-01-03 | Nippon Petrochemicals Company Limited | Fibrillated weatherproof webs having network structure, nonwoven fabrics made from the webs, and processes for the production of the webs and nonwoven fabrics |
-
1987
- 1987-11-20 NZ NZ22263287A patent/NZ222632A/en unknown
-
1988
- 1988-11-18 AU AU25700/88A patent/AU617714B2/en not_active Withdrawn - After Issue
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU592037B2 (en) * | 1987-02-05 | 1989-12-21 | Kureha Kagaku Kogyo Kabushiki Kaisha | Polyamide based films and laminates |
| AU602203B2 (en) * | 1987-03-26 | 1990-10-04 | E.I. Du Pont De Nemours And Company | Multi-layer plastic container |
| AU605051B2 (en) * | 1988-11-09 | 1991-01-03 | Nippon Petrochemicals Company Limited | Fibrillated weatherproof webs having network structure, nonwoven fabrics made from the webs, and processes for the production of the webs and nonwoven fabrics |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU643035B2 (en) * | 1990-06-27 | 1993-11-04 | Gunze Limited | Multi-layer films and process for prepartion thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| AU2570088A (en) | 1989-05-25 |
| NZ222632A (en) | 1989-07-27 |
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