AU686297B2

AU686297B2 - A package and a packaging process

Info

Publication number: AU686297B2
Application number: AU13665/95A
Authority: AU
Inventors: Henry G. Schirmer
Original assignee: WR Grace and Co Conn; WR Grace and Co
Current assignee: Cryovac LLC
Priority date: 1994-03-11
Filing date: 1995-03-07
Publication date: 1998-02-05
Anticipated expiration: 2015-03-07
Also published as: JPH07315342A; ZA951745B; BR9501031A; CA2134920A1; KR950031799A; NZ270596A; TW348147B; AU1366595A

Description

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION NAME OF APPLICANT(S): W. R. Grace Co.-Conn.

ADDRESS FOR SERVICE: DAVIES COLLISON CAVE Patent Attorneys 1 Little Collins Street, Melbourne, 3000.

INVENTION TITLE: A package and a packaging process The following statement is a full description of this invention, including the best method of performing it known to me/us:e BACKGROUND OF THE INVENTION i. Field of the Invention The present invention relates to a method of, and apparatus for, packaging an article in a receptacle to obtain a substantially oxygen free pack. In particular, the present invention relates to a method of and apparatus for Sproducing a package including a meat product in a substantially oxygen free eoee o 0 heat shrinkable thermoplastic receptacle utilizing an inert atmosphere and a oe hot air shrinking means.

2. Description of the Related Art oeeeo It has been know-n to package an article in plastic envelopes, such as a plastic bag, by loading the article in the envelope and then inserting the loaded 15 envelope into a vacuum chamber for the atmosphere around the envelope to be reduced in pressure so that the air or other gas within the envelope is extracted and finally the envelope can be sealed under low pressure conditions.

The resulting package is termed a "vacuum package".

It is also known for the operation of the process to be such that during the reduction in pressure of the atmosphere around the envelope, the wall of the envelope balloons away from the enclosed article, so that the extraction of air from within the envelope can be more effectively carried out. Such systems using, for example, a nozzle to extract air from within the envelope while the pressure of the atmosphere around the envelope has been reduced to effect the necessary ballooning action are known. Ballooning action is also known in which the vacuum chamber in which the envelope is closed has two portions of which a first portion encloses the envelope mouth and the second portion encloses the article-enclosing remainder of the envelope so that the pressure around the exterior of the envelope can initially be reduced more rapidly than the pressure within the envelope (in order to promote the desired ballooning effect). Increased effectiveness of ballooning using several cycles of reducing I I~L I 11 1 IN 11 .11 Ili I INIA 91 "Al V I 1' W -2the pressure around the envelope and within the envelope to help insure removal of any trapped pockets of oxygen containing gas is also known.

In all of these methods there is a necessity of using a vacuum chamber to remove the oxygen containing atmosphere and a hot water heat shrink apparatus to effectuate the shrinking of the heat shrinkable film envelope. The use of a vacuum chamber requires expensive, energy intensive equipment that also limits the speed of packaging the desired articles. The use of a hot water shrinking means is also energy intensive, and exposes the packaged article to heat for a relatively extended period which then requires extended cooling before the packaged product is ready for further distribution.

SUMMARY OF THE INVENTION According to one aspect of the present invention there is provided a process for Spackaging a meat product comprising the steps of: a) covering a meat product with a heat shrinkable thermoplastic oxygen barrier S: 15 film formed in tubular shape around the meat product; Sb) flushing the:meat product with a substantially oxygen free flushing gas obtained from a gas flushing means; c) sealing a longitudinal seam flap of the tubular shaped heat shrinkable thermoplastic film; d) sealing the meat product and a quantity of the substantially oxygen free flushing gas within the heat shrinkable thermoplastic film by transverse sealing; e) separating the product containing portion of the tubular shaped heat shrinkable thermoplastic film from the heat shrinkable thermoplastic film by transverse cutting; f) removing the heat shrinkable thermoplastic film sealed product from the gas flushing means; g) providing a flushing gas exit hole in the heat shrinkable thermoplastic film; h) heat shrinking the heat shrinkable thermoplastic film against the meat product contained therein; i) removing the shrink wrapped product from the heat shrinking means; and j) sealing the flushing gas exit hole to create a gas flushing exit hole seal.

-3- According to the invention, the product may be loaded onto a tray or a slab prior to covering of the product with the heat shrinkable thermoplastic oxygen barrier film in step a), The invention also provides a package produced by a process as described in either one of the immediately preceding two paragraphs.

According to another aspect of the present invention there is provided a package comprising a) a meat product; b) a heat shrinkable thermoplastic oxygen barrier film disposed around the meat product to form a container for the meat product; c) a substantially oxygen free flushing gas disposed within the container formed by the heat shrinkable thermoplastic film; d) a flushing gas exit hole disposed in the heat shrinkable thermoplastic film; and e) a flushing gas exit hole sealing patch disposed over the flushing gas exit hole.

According to a further aspect of the present invention there is provided a package 15 comprising: a) a meat product; ;i b) a tray or slab on which the meat product rests; c) a heat shrinkable thermoplastic oxygen barrier film disposed around the meat product and the tray or slab to form a container for the meat product; 20 d) a substantially oxygen free flushing gas disposed within the container formed by the heat shrinkable thermoplastic film; and e) a flushing gas exit hole disposed in the heat shrinkable thermoplastic film.

*e Preferred forms of the invention, as well as other embodiments, objects, features and advantages of this invention, will be apparent from the following detailed description which is to be read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings which are appended hereto and make a part of this disclosure.

Q FIG. 1 shows a schematic view of the apparatus of the present invention.

I I I' tl II A111) IV1A V ,14 1 I'l 3A- FIG. 2 shows the film being formed in a tube shape and flap ready to be sealed by flap sealing means.

FIG. 3 shows a schematic view of another embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION The present invention will be better understood from the specification taken in conjunction with the accompanying drawings in which like reference numerals refer to like parts.

FIG. 1 shows a schematic view of the apparatus 1 of the present invention wherein product indexing means 2 transports product 3 to gas flushing means 4. Product 3 a sub-primal of fresh red meat) is covered with heat

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PAT',NT

Case No. 3-4100 shriinkable thermoplastic film 6 introduced from film supply 5 such that film 6 forms a tube shape around product 3 in area 7. Bottom longitudinal flap sealing means 8 then seals the product 3 and the gas introduced by gas flushing means 4 within film 6, having been sealed by bottom longitudinal flap sealing means 8 and transverse sealing and cutting means 9. The now sealed and flush gas filled film 6 containing product 3 has a flushing gas exit hole 11 punched in it using hot needle means 10. The film 6 is next heat shrunk around product 3 using a hot air shrinking means 12. The presence of the flush gas causes the film to balloon away from the product 3 and prevents the film, during the heat shrinking process, from sticking to the product and thereby forming gas pockets. Additionally, because the flushing gas is substantially oxygen free any gas trapped between the product and the film will not have a detrimental effect upon the product. Upon exiting the hot air shrinking means 12 a film patch 13 is sealed over exit hole 11 producing a 15 product 5 sealed in a sealed heat shrunk barrier film 6 which is removed from 'indexing means 2 for shipment or further processing.

Yet another form of the present invention relates to a process for packaging a tray or slab loaded product, in a substantially oxygen free container of heat shrinkable, thermoplastic film.

20 Still another form of the present invention relates to a process for packaging a product and an oxygen scavenging agent in a substantially oxygen Sfree container of heat shrinkable, thermoplastic film.

Fig. 2 shows a cross-section of Fig. 1 at line A-A where the film 6 has been formed into a tubular shape and the flap 20 is ready to be sealed by flap sealing means 8. Optionally, an adhesive 21 may be used to seal, or help seal the flap In Fig. 3 is shown another embodiment of the present invention where the product 3 is loaded into an oxygen barrier tray 30 before introduction to the product indexing means 2. Indexing means 2 then transports product 3 to gas flushing means 4. Product 3 is covered with heat shrinkable thermoplastic film 6 introduced from film supply 5 such that film 6 forms a tube shape around product 3 in area 7. Bottom longitudinal flap sealing means 8 then seals the product 3 and the gas introduced by gas flushing means 4 within film 6, having been sealed by bottom longitudinal flap sealing means 8 and transverse sealing means 9 and cutting means 31. The now sealed and flush gas filled film 6 containing product 5 has a flushing gas exit hole 11 punched in it usiny hot needle means 10, The film 6 is next heat shrunk around product 3 using a hot air shrinking means 12. Because the flushing gas is substantially oxygen free any gas trapped between the product and the film will not have a detrimental effect upon the product. Upon exiting the hot air shrinking means 12 a sealing means 32 seals the film 6 to the edges of an oxygen barrier tray 30 producing a product 3 sealed in an oxygen barrier sealed tray 30/heat shrunk barrier film 6 which is removed from indexing means 2 for shipment or further proce sing.

The film tube forming apparatus is well known in the art and may be, for example, an apparatus such as K-PAK machines supplied by Kartridge Pak Inc. Likewise, the longitudinal flap sealing means and the transverse sealing and cutting means are well known in the art and need no further discussion here.

Hole punching means and the particularly preferred hot needle means for punching holes in film are well known in the art and need no further discussion here. Likewise, hot air shrinking of heat shrinkable film and apparatus to do this, such as apparatus which use hot S air and operate a temperature of from about 200°F to about 400 0 F, are well known by those oI.. skilled in the art and thus no further discussion is required here.

The indexing means is preferably a conveyer system or series of conveyer systems, but any suitable indexing system, whether manual or automatic may be employed in the present invention. Further, while the complete indexing system apparatus and control systems are not shown, they are well understood by those skilled in the art and further description is not necessary to utilize the present invention.

Suitable heat shrinkable thermoplastic materials for use in the present invention, include oriented films, and oriented film laminates where at least one film of the laminate is a heat shrinkable thermoplastic film. As used herein "film" is defined as a single layer or coextruded multiple layers. Also, as used herein, "laminates" is defined as a multi-film material having at least one oriented film. Presently preferred are oriented films, particularly biaxially oriented films. These films may be of a single layer or of multiple layer construction. Multilayer films may contain more than one layer of the same film composition or may contain different film compositions in one or more layers of the multiple% layer film. Ih iaddition, those matt rial, mIay bo (.w(tn1truded or laminated, Film compositions suitable for use in the present invention include, for example, an outer layer (food side) layer of ELVAX 3128 ethylene vinyl acetate copolymer (EVA), a first inner layer of a blend comprising 80% by weight Dowlex 2045 linear low density polyethylene from Dow Chemical, plus 20%1 by weight of EZ705-009 ethylene n-butyl acrylate copolymer from Quantum Chemicals, a second inner layer of saran vinylidene chloride/vinyl chloride copolymer, or vinylidene chloride/methyl acrylate copolymer), and a second outer layer of ELVAX 3128 EVA copolymer. Another preferred film formulation comprises an outer layer (food side) comprising a blend of 90,"0 by weight of NA 295-000 EVA copolymer from Quantum Chemicals and 10% by weight Dowlex 2045 or comprising 85/10 by weight of Dowlex 2045 and 15X by weight of Quantum EA719-009 ethylene n-butyl acrylate copolymer, a first inner layer of a blend comprising 80/% by weight Dowlex 2045 from Dow Chemical, plus 20" by weight of EZ705-009 from Quantum Chemicals, a second inner layer of saran, and a second outer layer comprising 92.5% by weight of an EVA copolymer (LD 318.92 from Exxon) plus 7.5% by weight of Dowlex 2045.

"Patch materials suitable for use in the present invention may comprise the same compositions as the heat shrinkable film or may be different. The patch material preferably also have the necessary oxygen barrier properties to prevent oxygen contamination of the product. The patch may or may not be heat shrinkable since it is applied to the packaged product after hot air shrinking of the film containing the product. Further, the patch may be applied us- .25 ing any known attaching means including adhesives and heat sealing. A presently preferred patch material comprises the same material composition as I used for the heat shrinkable thermoplastic material. The flushing gas exit hole may alternatively be sealed using a seal selected from the group consisting of a barrier tray, a barrier slab, a barrier foam tray and a barrier foam slab.

Optionally, the present invention may have an oxygen scavenging agent introduced into the package before sealing. Suitable oxygen scavenging agents are well known in the art and include, for example, AGELESS™' oxygen scavenging packets supplied by W. R. Grace Co., Conn. through its packaging division.

Although the illustrative embodiments of the present invention have been described herein with reference to the accompanying drawings it is to be understood that the invention is not limited to those precise embodiments and that various other changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention.

For example, although the preferred tray to be used in connection with this invention is an "oxygen barrier" tray, a tray having either inherently low oxygen transmission properties, or having an oxygen barrier film or laminate adhered to one or more surfaces of the tray, other trays or supports can be used in connection with the invention. Those skilled in the art will understand that the selection of the tray or support type will depend in part on the type of product to be packaged, and the desired shelf life in the case of food products).

Also, various olefinic and other thermoplastic polymer materials can be used in suitable proportions as the component of a heat shrinkable film or laminate useful in the present invention. Again, the skilled routineer will select such materials on the basis of desired functionalities, intended end use, and other considerations.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Claims

1. A. process for packaging a meat product comprising the steps of: a) covering a meat product with a heat shrinkable thermoplastic oxygen barrier film formed in tubular shape around the meat product; b) flushing the meat product with a substantially oxygen free flushing gas obtained from a gas tJ.,shing means; c) sealing a longitudinal seam flap of the tubular shaped heat shrinkable thermoplastic film; d) sealing the meat product and a quantity of the substantially oxygen free flushing gas within the heat shrinkable thermoplastic film by transverse sealing; e) separating the product containing portion of the tubular shaped heat shrinkable ;thermoplastic film from the heat shrinkable thermoplastic film by transverse cutting; f) removing the heat shrinkable thermoplastic film sealed product from the gas flushing means; g) providing a flushing gas exit hole in the heat shrinkable thermoplastic film; h) heat shrinking the heat shrinkable thermoplastic film against the meat product contained therein; o.. i) removing the shrink wrapped product from the heat shrinking means; and j) sealing the flushing gas exit hole to create a gas flushing exit hole seal.

2. A process as claimed in Claim 1 wherein, the flushing gas comprises substantially oxygen free nitrogen and carbon dioxide.

3. A process as claimed in Claim 1 or 2 wherein, the longitudinal seam flap is created using a heat sealing means.

4. A process as claimed in any one of Claims 1 to 3, wherein, sealing the product and a quantity of the flushing gas within the heat shrinkable thermoplastic film by sealing and g separating the product containing portion of the tubular shaped heat shrinkable thermoplastic I I V 111 1 a 1 W O film is accomplished using a heat sealing and heat cutting means.

A process as claimed in any one of Claims 1 to 4 wherein, the flushing gas exit hole is produced using a hot needle hole producing means.

6. A process as claimed in any one of Claims 1 to 5 wherein, the heat shrinking means uses hot air and operates at a temperature of from about 200°F to about 400°F.

7. A process as claimed in any one of Claims 1 to 6 wherein, the flushing gas exit hole is sealed using a seal selected from the group comprising a thermoplastic barrier film sealing patch, a barrier tray, a barrier slab, a barrier foam tray or a barrier foam slab.

8. A process as claimed in any one of Claims 1 to 7 wherein, the gas flushing exit hole seal is heat sealed to the heat shrinkable thermoplastic film.

9. A process as claimed in any one of Claims 1 to 7 wherein, the gas flushing exi, nole •seal is adhesively sealed to the heat shrinkable thermoplastic film.

A process as claimed in any one of Claims 1 to 9 wherein, the product is load Into a tray before proceeding to step a),

11. A process as claimed in any one of Claims 1 to 9 wherein, the product is loaded onto a slab before proceeding to step a).

12. A package produced by the process as claimed in any one of Claims 1 to 11ii.

13. A package comprising a) a meat product; b) a heat shrinkable thermoplastic oxygen barrier film disposed around the meat R I product to form a container for the meat product; I r ra~ wrr~- 1 111*11 r~~--nnl r- P( AII It AflIPA 41,~ 1191 1111011 c) a substantially oxygen free flushing gas disposed withmn the container formed by the heat shrinkable thermoplastic film; d) a flushing gas exit hole disposed in the heat shrinkable thermoplastic film; and e) a flushing gas exit hole sealing patch disposed over the flushing gas exit hole.

14. A package comprising: a) a meat product; b) a tray or slab on which the meat product rests; c) a heat shrinkable thermoplastic oxygen barrier film disposed around the meat product and the tray or slab to form a container for the meat product; d) a substantially oxygen free flushing gas disposed within the container formed by the heat shrinkable thermoplastic film; and e) a flushing gas exit hole disposed in the heat shrinkable thermoplastic film.

15. A package as claimed in claim 14 further comprising a flushing gas exit hole sealing Spatch disposed over the flushing gas exit hole.

16. A packaging process substantially as hereinbefore described with reference to the drawings.

17. A package substantially as hereinbefore described with reference to the drawings. DATED this 17th day of October 1997. W. R. GRACE CO.-CONN. by their Patent Attorneys DAVIES COLLISON CAVE I PATENT Case No. 3-41900 ABSTRACT The present invention relates to a method of packaging meat products in an oxygen free package using a hot air heat shrinking method for shrinking a heat shrinkable thermoplastic film around the meat product. The need for a vacuum chamber is eliminated. The problem of trappinb oxygen within the package is eliminated by using a oxygen free flush gas. f S. 55 5