JP2004269053A - Heat-shrinkable package - Google Patents

Heat-shrinkable package Download PDF

Info

Publication number
JP2004269053A
JP2004269053A JP2004044321A JP2004044321A JP2004269053A JP 2004269053 A JP2004269053 A JP 2004269053A JP 2004044321 A JP2004044321 A JP 2004044321A JP 2004044321 A JP2004044321 A JP 2004044321A JP 2004269053 A JP2004269053 A JP 2004269053A
Authority
JP
Japan
Prior art keywords
seal
bag
film
tube
heat
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP2004044321A
Other languages
Japanese (ja)
Other versions
JP4750367B2 (en
JP2004269053A5 (en
Inventor
David A Busche
Gregory Robert Pockat
Thomas Andrew Schell
グレゴリー・ロバート・ポカット
デイビッド・エイ・ブッシェ
トマス・アンドルー・シェル
Original Assignee
Curwood Inc
カーウッド・インコーポレイテッド
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Family has litigation
Priority to US10/371,950 priority Critical patent/US20040166261A1/en
Priority to US10/371950 priority
Priority to US10/645186 priority
Priority to US10/645,186 priority patent/US7527839B2/en
Application filed by Curwood Inc, カーウッド・インコーポレイテッド filed Critical Curwood Inc
Publication of JP2004269053A5 publication Critical patent/JP2004269053A5/ja
Publication of JP2004269053A publication Critical patent/JP2004269053A/en
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=32737997&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=JP2004269053(A) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application granted granted Critical
Publication of JP4750367B2 publication Critical patent/JP4750367B2/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65DCONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D75/00Packages comprising articles or materials partially or wholly enclosed in strips, sheets, blanks, tubes, or webs of flexible sheet material, e.g. in folded wrappers
    • B65D75/002Packages comprising articles or materials partially or wholly enclosed in strips, sheets, blanks, tubes, or webs of flexible sheet material, e.g. in folded wrappers in shrink films

Abstract

PROBLEM TO BE SOLVED: To provide a heat-shrinkable packaging container which is easy to manufacture and has a seal which can be easily peeled off by hand, a break resistance and a strong end seal.
To solve this problem, individual end-sealed packaging containers such as bags formed from sheets of heat-shrinkable film having a first edge and a second edge opposite thereto. I will provide a. The packaging container comprises a first bag wall, a second bag wall, opposed first and second lay flat edges, a second lay flat edge, and a distal end having the first edge coupled to the second edge. A first seal defining a tube member having a portion and an opening. Also, the packaging container extends laterally through the first edge and the second edge across the width of both the first and second walls, thereby closing the second end. Including seals. Preferably, at least one of the first and second seals is a peelable seal. This first seal can be a wrap seal, fin seal, butt seal or seal strip. Also disclosed is a method of forming individual end-sealed heat-shrinkable packaging containers.
[Selection diagram] Fig. 1

Description

  The present invention relates to shrink wrapping of articles, particularly foodstuffs such as chicken, cheese, partial or block meat, raw red meat and other processed meats, fruits, vegetables, breads and foods. Shrink wrap refers to the use of a packaging film manufactured in such a way that when exposed to a predetermined amount of heat, it preferably shrinks in both directions to reduce its overall surface area. As this type of film wraps around the object, seals its edges, and as it passes through the heat shrink tunnel where the package is exposed to high temperatures, the film reacts to heat and reacts to the heat of the object. Will shrink around. Depending on the respective application, the air trapped in the package can be evacuated before the last seal, or a small hole can be made in the film to allow the air to escape during the heat shrinking process. This method produces an attractive package that fits the article. There are a number of articles packaged using shrink wrap, which can include foodstuffs such as frozen pizza, cheese, chicken, raw red meat and processed meat products.

  Shrink packaging of foods such as chicken, cheese, raw red meat and processed meat products is used in making individual heat shrinkable packaging containers such as pouches and bags for packaging such foods. It requires a suitable tough, fracture-resistant, and even flexible film material to do so. Generally, shrink wrapping of food involves placing a given food or article in an individual container, evacuating the container so that the container is deflated, removing air, and heat sealing over the opening or mouth of the container. The container is closed and then exposed to a heat source such as a stream of warm air, infrared radiation, hot water, etc., thereby causing the container to shrink and reduce the heat shrink properties of the container by making direct contact with the outer shape of the food or article. Is based on The packaged article produced by this packaging method has an attractive appearance that increases the commercial value of the packaged article, its contents are kept in a sanitary condition, and the shopper is It is possible to examine the quality of goods. In addition, this type of packaging removes air from the package and extends the shelf life.

  The present invention relates generally to packaging, and more particularly to a heat shrinkable packaging for foodstuffs that can be easily opened with a hermetically sealed heat seal.

  Wrapping an article such as food with a thermoplastic film or laminate to protect the food to be packaged from misuse and external contamination, and to provide a convenient and durable package for transport, and Selling to is what is commonly done. Shrink wrapping of food products has many of its advantageous properties that increase the commercial value of the packaged article, such as strength, compactness, content safety, purge resistance, and attractive appearance of the packaged article. It has come to be widely used.

  Shrink wrapping is a packaging film that shrinks in at least one direction, preferably in both directions, over its length or width when exposed to a predetermined amount of heat, to reduce its overall surface area. To use what is manufactured by the method. When an article is packaged with this type of film, the air in the package is usually vented, and the package typically removes the package from the film as the film responds to heat to the object. It is passed through a heat shrink tunnel that is exposed to high temperatures that shrink around. This method produces an attractive package that adheres to the object. There are a number of articles packaged using shrink wrap, including foodstuffs such as frozen pizza, cheese, chicken, raw red and processed meat products, and non-food such as wooden blinds, CDs, and the like. Food industry articles may be included.

  Many food products such as chicken, raw red meat, cheese and processed meat products are packaged in individual bags of pre-manufactured heat shrinkable film. Typically, individual bags or pouches for packaging foodstuffs have one to three edges that are heat sealed by the bag manufacturer (1 And a final seal performed by the food processor. Such individual bags typically make a seamless tube of heat shrinkable film having the desired diameter from the shrink film, heat seal one end of the single tubular film, and Manufactured by cutting the tube section, including the sealed section, thereby forming individual bags. The bag formed thereby flattens the bottom edge formed by heat sealing, the opening on the opposite side of the sealed bottom, and the folds that occur when the tube is flattened. And two seamless side edges formed by the eyes. An alternative to forming the bag from a seamless tube involves making a transverse seal spaced across the tube and cutting open the edge of the tube. If a flat sheet of film is used, the bag can be formed by heat sealing the three edges of the two superimposed film sheets, or by folding the end of the flat sheet and sealing the two edges. Formed from it. U.S. Patents describing well-known heat shrinkable bags include U.S. Patent Nos. 6,511,688, 5,928,740 and 6,015,235. U.S. Patent Application Serial No. 10 / 371,950, filed February 20, 2003 (Thomas Schell et al., Entitled "Heat-Shrinkable Packaging Receptacle", see if desired) is preferably a continuous method of film. Disclosed are individual heat-shrinkable bags formed from a sheet, wherein the opposite side edges of the sheet are longitudinally sealed to form a tube member, which is then transversely sealed and The tube member is cut to close the distal end of the tube member, thereby forming a seamed bag on the back.

  Known bags for heat shrink wrapping include a last strong hermetic seal at the factory to prevent the heat sealed seam from pulling apart during the heat shrink operation or during the shipping and transportation of the packaged article. While this strong heat seal provides protection against unwanted seal breakage, such seals also make it difficult for the end consumer to open the package. Thus, it includes a seal of sufficient seal strength to survive the heat shrinking process and operation and withstand the spontaneous opening that occurs due to the remaining shrinking forces, and without requiring the use of knives or cutting instruments. And the packaging material is torn or ruptured uncontrolled or randomly, for example separately from the sealing surface (this creates openings in undesirable places or causes a sudden breakage of the package, and There is a need for an improved heat-shrinkable packaging container that includes at least one heat seal that can be easily opened by applying force without causing inadvertent contamination or spillage of the contents of the article.

  Typically, individual bags or pouches for packaging foodstuffs have one to three edges (one edge left open to allow the product to be inserted) that is heat sealed by the manufacturer. To). Such individual bags generally make a seamless tube of heat shrinkable film of the desired diameter from the shrink film, heat seal one end of a single tubular film, and seal the The two seamless sections formed by cutting the tube section containing the section and thereby flattening it, the heat seal, the opening opposite the sealed bottom, and the flattening created when flattening Manufactured by forming a bag having side edges. An alternative to forming a bag from a seamless tube involves making two lateral seals spaced across the tube and cutting the edge of the tube. If a flat film sheet is used, the bag may be formed by heat sealing the three edges of the two superimposed film sheets, or by folding the end of the flat sheet and sealing the two edges. Formed from it.

The manufacture of bags from seamless tubes requires extruding the tubes to a specific width for the intended end use. Thus, the production of small diameter tubes for small width bags is not economical because it does not use the full capacity of the film production equipment. Also, the size of the seamless tube is limited by manufacturing equipment that can make the width as small as possible. A method of making an individual bag by overlapping two sheets and sealing about three edges is to process separate sheets, properly align the sheets, and wrap around several edges. Requires expensive machinery to provide the seal. In addition, having a third seal edge (four seal edges when closed) increases the risk of seal breakage during the shrink process. Folding the film sheet and sealing the two edges produces a double thickness film at these seals, which undesirably protrudes from the sides of the finished package.
US Pat. No. 6,511,688 U.S. Pat. No. 5,928,740 US Pat. No. 6,015,235 US Patent Application Publication No. 10/371950

  Thus, while the known shrink bags meet many of the requirements for packaging applications, there is an improved heat shrink bag structure that can be economically manufactured and sealed at the packaging site using standard bag sealing machinery. Further needs exist.

  In accordance with the present invention, there is provided an individual end-sealed packaging container such as a bag formed from a sheet of heat shrinkable film having a first edge and a second edge opposite thereto. In this packaging container, the first edge portion and the second edge portion are joined to form a first bag wall portion, a second bag wall portion, opposing first lay flat bag edge and second lay flat bag edge, and a terminal. A first seal defining a tube member having a portion and an opening. The packaging container includes a second seal extending laterally across the width of both the first and second walls through the first and second bag walls, thereby closing the end.

  The present invention also provides an easy-open heat-shrinkable bag that is heat-sealed in a sealed state to accommodate and protect the product disposed therein. At least one heat seal is peelable and can be easily opened by applying force. The bag is formed from a sheet of film having a first side, a second opposite side, an outer surface, and an inner surface. The bag includes a first seal that longitudinally seals the first and second sides, thereby defining a tube member. This tube member, when flattened, has a first bag wall, a second bag wall, a first bag edge, a second bag edge opposite thereto, an opening, and a distal end. including. The bladder includes a second seal that extends laterally near the distal end over the tube member, thereby sealing the first and second bladder walls together and closing the distal end. . A product storage chamber is defined between the first and second bag walls, the second seal and the opening. Preferably, the first seal comprises a wrap seal, and this is at least one peelable heat seal.

  A preferred embodiment of the heat-shrinkable packaging container of the present invention is shown generally in FIGS. The bag 10 is formed from a sheet of a heat-shrinkable film 11, which has a first edge 12, a second edge 14, a top surface 13 and a bottom surface 15. The bag 10 includes a first seal 16, which joins the first edge 12 and the second edge 14 from top to bottom of the bag in an overlapping arrangement, ie, a wrap seal. The tube member 18 shown in FIGS. 1 and 2 is formed in a partially lay-flat position, which comprises a first bag wall 20, a second bag wall 22, a first bag edge 24, , A second bag edge 26, an opening 28, and a bag end 30. In other words, the first bag edge 12 and the second bag edge 14 are located in an overlapping arrangement, and between the top surface 13 of the first edge 12 and the bottom surface 15 of the second edge 14. Is provided with a seal, such as a heat seal, such that the top surface 13 of the first edge 12 is sealed in face-to-face contact with the bottom surface 15 of the second edge. The bag 10 includes a second seal 32, which is provided through the first bag wall 20 and the second bag wall 22 and extends laterally across the bag 10 from the first bag edge 24 to the second bag edge 26. , Thereby closing the bag end 30 and defining a product receiving chamber 34.

  Although the first seal 16 is illustrated as being located between and extending parallel to the first bag edge 24 and the second bag edge 26, those skilled in the art will appreciate this disclosure. In consideration of the above, when the bag 10 is in the lay flat state, the position of the first seal 16 is changed from the first edge 24 to the second edge 26 to the first bag wall portion 20 or the second bag wall portion 22. May be located at any desired location, as well as being located at either the first bag edge 24 or the second bag edge 26. Although the second seal 32 is illustrated as being straight and extending perpendicular to the first seal 16, those skilled in the art will recognize that the second seal 32 It will be appreciated that any shape may be employed as long as it is operated to close, thereby defining the product compartment 34. For example, common seal shapes include straight or linear seals that typically extend perpendicular to the bag edges 24 and 26 (the bag edges 24 and 26 generally extend parallel to each other), and For example, non-linear or curved edges such as those described in US Pat. No. 5,149,943. Please refer to the disclosure if desired. Both linear and non-linear seals can be made by any suitable sealing method known in the art, including heated rod and impulse sealing methods.

  A second embodiment of the heat shrinkable packaging container of the present invention is illustrated generally in FIGS. Bag 110 is formed from a sheet of heat shrinkable film 111, which has a first edge 112, a second edge 114, a top surface 113, and a bottom surface 115. The bladder 110 includes a first seal 116 that joins the first edge 112 and the second edge 114 in abutting, or fin, seal, thereby defining a tube member 118. To form a first seal 116, the first edge 112 and the second edge 114 are aligned with each other such that the bottom surfaces 115 of both the first edge 112 and the second edge 114 are in face-to-face contact. And provide a seal such as a heat seal between them. The tube member 118 is shown in FIGS. 3 and 4 in a partially lay-flat configuration, including a first bladder wall 120, a second bladder wall 122, a first bladder edge 124, and , A second bag edge 126, an opening 128, and a bag end 130. The bag 110 includes a second seal 132, which is provided through a first bag wall 120 and a second bag wall 122 and extends from the first bag edge 124 to the second bag edge over the bag 110. Extends laterally to section 126, thereby closing bag end 130 and defining product receiving chamber 134.

  Also, although the first seal 116 is illustrated as being located between the first bag edge 124 and the second bag edge 126, those skilled in the art will appreciate the first seal in light of this disclosure. The position of 116 is from the first edge 124 to the second edge when the bag 110 is in the lay flat condition at any desired position of either the first bag wall 120 or the second bag wall 122. And will be located at both the first edge 124 and the second edge 126. The first seal 116 forms a fin 117 that extends outwardly from the tube member 118, so that the first seal 116 preferably has a first bag edge and a second bag edge at or near the center of the bag wall. It is located at a point between the edges. In this embodiment, the fins 117 are folded flat against the respective bag wall from which they extend, and the second seal 132 and the last hermetic seal (not shown) are finned in such a folded position. 117 will work. This advantageously eliminates undesired aesthetic fin seals at the side edges of the packaged product. Like the second seal 32, the second seal 132 is also illustrated as being straight and extending perpendicular to the first seal 116. One of ordinary skill in the art will appreciate that the second seal 132 may act to close the bag end 130, as described with respect to the second seal 132, thereby defining the product storage chamber 134. It will be appreciated that any shape, such as a curved shape, can be taken.

  Another embodiment of the present invention is illustrated in FIGS. Bag 210 is formed from a sheet of heat shrinkable film 210, which has a first edge 212, a second edge 214, an inner surface 213, and an outer surface 215. The bag 210 includes a first seal 216 that couples the first edge 212 and the second edge 214 directly to the surfaces of the first edge 212 and the second edge 214. Alternatively, it comprises a butt seal which is joined in a vertically adjacent relationship without being directly joined. The first seal 216 preferably includes a butt seal tape 217, one side of which is sealed to the outer surface 215 of the first edge 212 by a seal 216 a while the opposite side of the tape 217 is a second edge Is sealed with a seal 216b and seals 216a and 216b will be in the area adjacent and along the first edge 212 and the second edge 214. The first seal 216, shown in FIGS. 5 and 6 in a partially lay-flat state, defines a tube member 218, which includes a first bladder wall portion 220 and a second bladder wall portion 222. , A first bag edge 224, a second bag wall 226, an opening 228, and a bag end 230. The bag 210 includes a second seal 232, which is provided through the first bag wall 220 and the second bag wall 222 and extends from the first bag edge 224 to the second bag edge over the bag 210. Extends laterally into section 226, thereby defining a product receiving chamber 234.

  The film used to make the bags of the present invention can be a multi-layer or single-layer flexible heat-shrinkable film made by any known method. For example, in commercial chicken packaging operations, monolayer films made from polyethylene and / or ethylene / vinyl acetate copolymer and multilayer films containing polyethylene and / or ethylene / vinyl acetate copolymer are widely used. . Similarly, in packaging raw red meat and processed meat products, multilayer heat shrinkable films containing polyethylene and / or ethylene / vinyl acetate copolymer in one or more layers of the film Is commonly used. Preferred films also have one or more of the following properties, including high puncture resistance (eg, as measured in a ram and / or hot water puncture test), high shrinkage value, low haze, and high seal strength. Or all advantageous combinations thereof may be provided. The film and / or bag can also include certain prints (eg, they can be printed). For example, a bag according to the present invention may preferably include a print indicating that the bag contains a product containing bone. For applications printing this film, it may be desirable to corona treat the film surface to improve ink adhesion. Corona-treated surfaces are similar to untreated surfaces, but in most cases, they are not heat-sealed. It may be desirable to minimize mutual adverse effects with the area to be sealed. For example, a central portion of the film can be corona treated, but portions along each of the longitudinal edges of the film are not corona treated. In this manner, the respective longitudinal sections that are sealed together to form the first seal 16 or 116 as described above will not be corona treated and will have no adverse effects.

  Preferably, the film may have an unrestricted shrinkage of at least 20% in at least one direction, more preferably an unrestricted shrinkage of 35% or more in one direction or in both longitudinal and transverse directions. Free shrinkage is measured by cutting a 10 cm square piece for film measurement in each of the longitudinal and transverse directions. This film is immersed in water at 90 ° C. for 5 seconds. After removal from the water, the pieces are weighed and the difference from the original dimensions multiplied by 10 to get the percentage of shrinkage.

  The films used in the bags according to the invention can be single-layer or multi-layer films, but these bags preferably have two or more layers, more preferably three to nine layers, even more preferably three to seven layers. Formed from a multilayer film having Since the bags of the present invention are primarily intended to retain food after venting and sealing, it is preferred to use a thermoplastic film that includes an oxygen and / or moisture barrier. As used herein, the term "barrier" or "barrier layer" means a layer of a multilayer film that acts as a physical barrier to moisture or oxygen molecules. A combination of barrier layer material and other film layers that are advantageous for packaging oxygen sensitive materials such as raw red meat is 70 cc / sq. Will provide an oxygen gas permeability in 24 hours (45 or less, more preferably 15 or less) and a relative humidity of 0%.

  The bags 10, 110 and 210 are preferably made continuously from a continuous sheet or web. The web is slit to the desired width and sent to a bag making machine, the longitudinal edges of the films are aligned with each other, and the wrap seal (bag 10), fin seal (bag 110) or butt seal (bag 210) is formed. Either seal longitudinally to form a continuous single seam tube or tube member. A transverse seal is made over the tube, and the portion containing the transverse seal is cut from the continuous tube to form individual bags.

  The type of first seal 16, 116 or 216 incorporated into the bag of the present invention must be considered when selecting a suitable film. Generally, heat seals are made by applying sufficient heat and pressure for a sufficient amount of time to cause welding between two polymer film surfaces between the polymer film layers. A general method for forming a heat seal is a heating rod sealing method in which at least one of the adjacent polymer layers is held in face-to-face contact by a bar which is heated, and , And at least one of which is held in face-to-face contact by a wire or ribbon that is energized for a very short period of time to generate sufficient heat to cause fusion of the film layer. Impulse sealing method. In general, the performance of the sealing layer of the film becomes even more important, as less area is bonded with the impulse seal as compared to the heated rod seal. However, impulse seals generally look good because they use less area to form a bond. The first seal 16, or wrap seal, requires that the top surface 13 and the bottom surface 15 can form a suitable heat seal therebetween. If it is intended to form a first seal 116, a fin seal, only the bottom surface 115 need not be able to form a suitable heat seal. This is because an interlayer bond will be formed between the same surfaces or layers. If a first seal 216, a butt seal, is formed, then both the top and bottom surfaces must be able to form a suitable heat seal. Similarly, the butt seal tape 217 must also be capable of forming a suitable heat seal with the top surface, or using a suitable adhesive, depending on whether the tape 217 is located inside or outside the bag 110. 217 must be adhered to the top surface 13 or the bottom surface 15.

  A preferred multilayer barrier film structure for use in the present invention is shown generally at 40 in FIG. If an oxygen barrier layer 42 is required, it is usually provided as a separate layer of a multilayer film, most commonly as a core layer sandwiched between an inner heat sealable layer 44 and an outer layer 46, Various properties of the tie layer or adhesive layer and the desired film, such as heat sealability, toughness, abrasion resistance, tear resistance, heat shrinkage, delamination resistance, rigidity, moisture resistance, optical properties, printability, etc. Additional layers, such as layers to add or improve, may also be included. Oxygen barrier materials that can be included in the films used for the bags of the present invention include ethylene vinyl alcohol copolymer (EVOH), polyacrylonitrile, polyamide, and vinylidene chloride copolymer (PVDC). Preferred oxygen-blocking polymers for use in the present invention are vinylidene chloride copolymers or copolymers of vinylidene chloride with various comonomers, such as copolymers with vinyl chloride (VC-VDC copolymer) or A copolymer with methyl acrylate (MA-VDC copolymer) and EVOH. Specifically, a preferred barrier layer is, for example, about 85% vinylidene chloride-methyl acrylate copolymer and about 15% vinylidene chloride-vinyl chloride, as described in US Pat. No. 4,798,751 to Schuetz et al. It consists of a copolymer. Suitable and preferred EVOH copolymers are described in U.S. Pat. No. 5,759,648. See these U.S. patents if desired.

An internal heat-sealable layer 44 is generally provided on the side of the barrier layer 42, which becomes the interior surface 38 or bottom surface 15 and 115 of the bag 10, 110 or 210 shown in FIGS. . Optionally, other film layers can be incorporated between the barrier layer 42 and the inner heat sealable layer 44 as described above. Substantially linear copolymers of ethylene and at least one α-olefin and copolymers of ethylene with an alkyl acrylate such as vinyl ester or vinyl acetate are useful in one or more layers of the film. It can be used and constitutes single and multilayer thermoplastic films. Preferably, the inner heat sealable layer comprises a blend of at least one ethylene / α-olefin copolymer (EAO) and ethylene vinyl acetate (EAO: EVA blend). Suitable α-olefins include C 3 -C 10 α-olefins such as propene, 1-butene, 1-pentene, 1-hexene, 1-methylpentene, 1-octene, 1-decene and mixtures thereof. Is mentioned. The heat seal layer is optionally the thickest layer of the multilayer film and can significantly contribute to the puncture resistance of the film. Another desired property affecting this layer is the heat seal temperature range. The temperature range for heat sealing this film is preferably as wide as possible. This allows for a greater change in the operation of the heat sealing device compared to a film having a very narrow range. For example, it is desirable to heat seal a suitable film over a wide temperature range that provides a heat sealing opportunity of 80 ° F. or higher.

An outer layer 46 is provided on the side of the barrier layer opposite the heat-sealable layer 44 and acts as an outer surface 39. In this case, when a wrap seal, such as first seal 32 of bag 10, is incorporated into the bag structure, outer layer 46 must be a heat seal that is compatible with the inner heat sealable layer. Optionally, other polymer layers can be provided between the barrier layer and the outer layer as discussed above. The outer layer can be composed of ethylene / α-olefin copolymer (EAO), ethylene vinyl acetate copolymer (EVA), or a blend thereof. EAO is mainly propene, 1-butene, 1-pentene, 1-hexene, 1-methylpentene, 1-octene, 1-C 3 -C 10 alpha-olefins one or more suitable, including such as decene Is a copolymer containing ethylene polymer units copolymerized with 50% by weight or less of an α-olefin. Preferred α-olefins are 1-hexene and 1-octene. Recent developments to improve the properties of heat shrinkable films include U.S. Pat. No. 5,403,668, which discloses a multi-layer heat-sensitive film in which the outer layer of the film is a quaternary blend of VLDPE, LLDPE, EVA and plastomer. A contractile oxygen barrier film is disclosed. Please refer to this disclosure if desired. LLDPE, a linear low density polyethylene, is a class of ethylene / α-olefin copolymer having a density of 0.915 g / cm 3 or more. VLDPE, also called ultra low density polyethylene (ULDPE) is a class of ethylene · alpha-olefin copolymer having a density of 0.915 g / cm 3 or less, a density of up 0.900~0.915g / cm 3 There are many commercial VLDPE resins available. Plastomers are EAOs that generally have a density of 0.900 g / cm 3 or less. U.S. Pat. No. 5,397,640 discloses a multilayer oxygen barrier film wherein at least one outer film layer is a blend of three components: VLDPE, EVA and plastomer. Alternatively, the outer layer may be, for example, a polyamide, a styrenic copolymer such as a styrene / butadiene copolymer, a polypropylene, an ethylene / propylene copolymer, an ionomer or an α-olefin polymer, and especially a linear low density polyethylene. A member of the polyethylene family such as (LLDPE), very low density polyethylene (VLDPE and ULDPE), high density polyethylene (HDPE), low density polyethylene (LDPE), ethylene vinyl ester copolymer or ethylene alkyl acrylate copolymer Alternatively, they may be formed from other thermoplastic materials, such as various blends of two or more of these materials.

  In general, the monolayer or multilayer film used in the heat shrinkable bags of the present invention will have the desired properties, such as puncture resistance, modulus, seal strength, barrier, for the particular packaging operation in which the film is to be used. It can have any desired thickness as long as it has a thickness and composition sufficient to provide properties, optical properties, and the like. For material efficiency and protection, it is desirable to use the minimum film thickness to provide the required puncture resistance and other properties. Preferably, the film has an overall thickness of from about 1.25 to about 8.0 mils, more preferably, from about 1.75 to about 3.0 mils.

  Suitable films for use in the present invention are disclosed in U.S. Patent No. 5,928,740. Please refer to this if desired. No. 5,928,740 discloses a first polymer of ethylene and at least one α-olefin having a polymer melting point of 55-75 ° C. and ethylene and a polymer having a polymer melting point of 85-110 ° C. and at least one α-olefin. A second polymer of olefins, preferably having a melting point of 115-130 ° C. selected from the group consisting of ethylene homopolymers such as HDPE and LDPE and ethylene copolymers with at least one α-olefin; A third thermoplastic polymer optionally and preferably with a fourth polymer such as a copolymer of ethylene and an alkyl acrylate or vinyl ester having a melting point of 80-105 ° C, preferably 90-100 ° C. A heat sealable layer comprising a blend is disclosed. No. 5,928,740 also discloses a specific example of a biaxially stretched, heat-shrinkable, three-layer barrier film suitable for use in the present invention. Specific examples of this three-layer barrier film are as described above, preferably combined with a barrier layer consisting of polyvinylidene chloride (PVDC) or vinylidene chloride-methyl acrylate copolymer (VDC MA or MA Saran) or an EVOH layer. Inner heat sealable layer and outer layer formed from at least 50%, preferably at least 70% by weight of a copolymer of ethylene and at least one α-olefin or at least one vinyl ester or a blend thereof. including. Also, preferred EVA will have a vinyl acetate content of about 3% to about 18%.

  Preferred films for use in the present invention are disclosed in US patent application Ser. No. 09 / 401,692, filed Sep. 22, 1999. See if desired. No. 09 / 401,692 discloses a first polymer having a melting point of 80-98 ° C., preferably 80-92 ° C., consisting of a monolayer and (a) a copolymer of ethylene and 1-hexene; (B) a second polymer having a polymer melting point of 115 to 128 ° C comprising a polymer of ethylene and at least one α-olefin, and (c) a copolymer of ethylene and an alkyl acrylate or vinyl ester. From a group consisting of a third polymer having a melting point of 60-110 ° C. and optionally (d) an ethylene homopolymer such as preferably HDPE and LDPE and an ethylene copolymer with at least one α-olefin. A fourth polymer having a selected melting point of 80 to 110 ° C. (preferably 85 to 105 ° C.), and optionally at least three polymer blends including the fourth polymer. Disclosed is a multi-layer film having at least one layer of a film. The blends of the present invention have been found to be useful as internal heat sealable layers in many multilayer embodiments. In a preferred three-, four- or five-layer embodiment, an oxygen barrier layer of vinylidene chloride copolymer, polyamide or EVOH comprises a layer of the blend of the invention and EAO or at least one vinyl ester or a blend thereof at least 50%. Between the layer containing either weight percent or another layer containing the blend of the present invention.

Additional preferred films for use in the present invention are disclosed in U.S. patent application Ser. No. 09 / 611,192, filed Jul. 6, 2000. See if desired. U.S. patent application Ser. No. 09/611192 has a melting point of 55-98.degree. C. consisting of at least one copolymer of ethylene and at least one comonomer selected from the group consisting of 1-hexene and 1-octene. 45 to 85% by weight of the first polymer, and 5 to 35% by weight of the second polymer having a melting point of 115 ° C to 128 ° C, comprising at least one copolymer of ethylene and at least one α-olefin. % Of at least one unmodified or anhydride-modified copolymer of ethylene and vinyl ester, acrylic acid, methacrylic acid or alkyl acrylate having a melting point of 60 to 110 ° C. Flexible thermoplastic biaxially stretched heat shrinkable film having at least one layer comprising a blend of at least three copolymers containing at least one weight percent Discloses a multilayer barrier embodiment formed from: wherein the first and second polymers are at least 50% by weight based on the total weight of the first, second and third polymers. Having a combined weight percent, yet the film of the bag has a total energy absorption of at least 0.70 Joules and a shrinkage value at 90 ° C. of at least 50% in at least one of the machine and transverse directions. Any suitable oxygen barrier material or blends thereof, such as ethylene vinyl alcohol copolymer (EVOH) or vinylidene chloride (VDC) vinyl chloride (VDC VC) or VDC methyl acrylate (VDC MA) A barrier layer formed from a VDC copolymer can be used. Preferably, the barrier layer comprises a blend of 85% by weight VDC.MA and 15% by weight VDC.VC. The outer layer is preferably an EVA / VLDPE blend, more preferably an EVA / VLDPE / plastomer blend. U.S. patent application Ser. No. 09 / 611,192 also discloses (i) ionomer polymers, such as ethylene / methacrylic acid copolymers, wherein the acid groups are partially or completely neutralized to form a salt, preferably zinc. or 5 to 20 wt% of what form the sodium salt, ethylene of at least one C 6 -C 8 with M W / M n of (ii) 55 to 95 ° C. of melting point and 1.5 to 3.5 (iii) from 0 to 90% by weight of a copolymer of ethylene having a melting point of 100 to 125 ° C and at least one C 4 to C 8 α-olefin; (Iv) 0 to 90% by weight of a copolymer of propylene and at least one monomer selected from the group consisting of ethylene and 1-butene and having a melting point of 105 to 145 ° C; And (v) ethylene and 1-hexene A copolymer with at least one monomer selected from the group consisting of 1-octene and 1-decene, having a melting point of 125 to 135 ° C. and containing at least two types of polymers containing 0 to 90% by weight; Also disclosed is a film comprising a flexible thermoplastic film having at least one layer of a blend of coalescing, wherein the polymers (ii), (iii), (iv) and (v) are: The film has a combined weight percent of at least 80% by weight based on the total weight of the polymers (i), (ii), (iii), (iv) and (v), and the film has at least 1. It has a total energy absorption of 2 joules. Optionally, the same blend may be used as an internal heat sealable layer for the bag film.

  Further preferred films for use in the present invention are described in U.S. Pat. ing. Please refer to these if desired.

In a preferred embodiment of the present invention, the heat-shrinkable bag is formed from a three-layer film. The three-layer film is preferably a biaxially stretched film including a barrier layer disposed between the inner heat-sealable layer and the outer layer, as shown in FIG. The inner heat sealable layer is about 37% ESCOLINE LD701.1 available from Exxon Chemical Company (Houston, TX, USA). Ethylene vinyl acetate (EVA) copolymer such as ID, about 24% VLDPE resin such as SCLAIR 10B (0.77 dg / min melt index and 0% available from Nova Chemicals, Calgary, Alberta, Canada) .911 g / cm 3 ), about 33% of a plastomer such as EXACT4053 available from Exxon Chemical Company (Houston, Tex., USA) and about 4% of Sparttech A27023 (lubricant / processing aid in VLDPE carrier resin). Lubricants / processing aids and about 2% of a blend of processing stabilizers, such as Spartech A32434 (available from Spartec Polycom of Washington, PA, USA). The barrier layer comprises a blend of about 15% vinylidene chloride vinyl chloride and about 85% vinylidene chloride methacrylate, as further described in U.S. Pat. No. 4,798,751. The outer layer is about 40% ESCOLINE LD701. Ethylene vinyl acetate (EVA) copolymer such as ID, about 33% plastomer such as EXACT4053, about 25% VLDPE resin such as SCLAIR 10B, and about 2% Ampacet 501236 (Ampaet, Taritown, NY, USA). (Available from Set Inc.), a blend of a processing aid / lubricant VLDPE carrier concentrate. The inner, barrier and outer layers are about 57.7%, 17.7% and 25.1%, respectively, based on the total thickness of the three-layer film.

In another preferred embodiment of the present invention, the heat-shrinkable bag comprises, as shown in FIG. 5, another three-layer biaxial stretch shrink including a barrier layer disposed between an inner heat-sealable layer and an outer layer. Formed from film. The barrier layer preferably comprises a blend of about 15% vinylidene chloride vinyl chloride and about 85% vinylidene chloride methacrylate as further described in US Pat. No. 4,798,751. The barrier layer preferably occupies approximately 16.5% of the thickness of the three-layer film. Internal heat sealable layer is preferably from a thickness of about 57.1% to occupy and EXACT9519 (0.895g / cm 3 and 2.2Dg / min n melt index of the film, Houston, TX, USA Exxon Chemical Company About 35.1% by weight of an ethylene / 1-hexene copolymer (as available), ATTANE XU61509.32 (density of about 0.912 g / cm 3 and 0.1% available from Dow Chemical Company, Midland, Mich., USA). 5dg / C 2 C 8 having a minute melt index (<10 wt% of C 8) VLDPE) about 36.5% of the ethylene-1-octene copolymers such as, ESCORENE LD701. ID (ethylene / vinyl acetate copolymer available from Exxon Chemical Company, Houston, Tex., USA) having a density of 0.93 g / cm 3, a vinyl acetate content of 10.5% by weight, and a melt index of about 0.19 dg / min. About 26.5% of an ethylene-vinyl acetate (EVA) copolymer, such as those reported to have a melting point of about 97 ° C., and Spartech A50050 (1.9% oleamide lubricant in VLDPE carrier resin); About 3% of a lubricant / processing aid such as a fluoroelastomer) and about 2% of a processing stabilizer such as Spartech A32434 (10% DHT4A in a VLDPE carrier resin available from Spartec Polycom of Washington, PA, USA). % Blend. The outer layer preferably accounts for about 26.4% of the film thickness and about 35% by weight of an ethylene / 1-hexene copolymer such as EXACT9519, ethylene / 1-octene such as ATTANE XU61509.32. About 35% of the copolymer, ESCOLINE LD701. It contains about 27% of an EVA copolymer such as ID, and about 3% of a lubricant / processing aid such as Spartech A50050 (available from Spartec Polycom of Washington, PA, USA).

In another preferred embodiment, the bag film comprises about 17% by weight of an ethylene / 1-octene copolymer such as ATTANE XU61509.32, about 18% by weight of ESCOLINEN LD701. EVA such as ID, ethylene / 1-hexene copolymer such as 58% EXACT 9110 (density of 0.898 g / cm 3 , melt index of 0.8 dg / min and melting point of 89 ° C.), about 2% And a biaxially stretched three-layer heat shrinkable film having an internal heat sealable layer made from a blend of a lubricant / processing aid such as Spartech A50050 and a lubricant of about 5% such as Spartech A50050. The outer layer comprises about 19% by weight of an ethylene / 1-octene copolymer such as ATTANE XU61509.32, 18% of EVA (ESCOLINE LD701.ID) and 60% of ethylene / 1-hexene copolymer such as EXACT9110. Coalescing and 3% processing aids such as A50056. The barrier layer is 85% vinylidene chloride-methyl acrylate and about 15% vinylidene chloride-vinyl chloride. Preferably, the ratio of the thickness of the inner layer: the barrier layer: the outer layer is about 62: 9: 29.

A preferred seven-layer film for use in making a bag according to the present invention is illustrated generally in FIG. The film 60 includes a first or internal heat-sealable layer 61 that preferably accounts for about 10% of the total weight of the film 60. The inner heat-sealable layer 61 preferably comprises about 94% EXACT 3139 (an ethylene-hexene copolymer having a reported melt index of 7.5 g / 10 min and a density of 0.900 g / cm 3 ), Consists of a blend of 4% Spartech A27023 and about 2% Spartech A32434. The second layer 62 adjacent to this first layer 61 preferably accounts for about 42.2% of the total weight of the film and about 37% of the ESCORENE LD701. ID, about 33% EXACT 4053, about 24% SCLAIR 10B, about 4% Spartech A27023, and about 2% Spartech A32434. Film 60 further includes a first tie layer 63 and a second tie layer 65, each of which individually and preferably accounts for about 5% of the total weight of film 60 and about 100% of VORIDIAN SP1330 (Tennessee, U.S.A.). (Ethylene-methyl acrylate copolymer, available from the Boridian Division of Eastman Chemical Company of Kingsport, Iowa). The film 60 includes a blocking layer 64 between the first tie layer 63 and the second tie layer 65. The barrier layer 64 preferably comprises about 17.7% of the total weight of the film and comprises a blend of about 85% vinylidene chloride-methyl acrylate and about 15% vinylidene chloride-vinyl chloride. This film includes a third layer 66 that preferably accounts for about 15.1% of the total weight of the film 60. This third layer 66 has about 40% of ESCOLINE 701. ID, about 33% EXACT4053, about 25% SCLAIR10B and about 2% Spartech A27339 blend. Film 60 preferably includes a fourth or outer layer 67 that comprises about 5% of the total weight of film 60 and comprises a blend of about 98% EXACT3139 and about 2% Spartech A27339. The total thickness of film 60 is preferably greater than about 2 mils.

  Advantageously, it may be desirable to use a high melt flow index polymer in the sealant layer of the film to help seal laterally across the wrap, butt or fin seal. The high melt flow index polymer has a melt flow index of about 5 dg / min or more. The higher melt flow index polymer will meet the size when the second seal 32, 132 or 232 is in the area of the first seal 16, 116 and 216 between the first and second bladder walls. Gaps such as gaps 9a (FIG. 2), 9b (FIG. 4) and 9c (FIG. 6) created due to differences are more easily filled than lower melt flow index polymers. For example, other high melt index polymers such as EXACT 3040 having a reported melt index of 16.5 g / 10 minutes may be applied to the inner layer 61 and outer layer 67 of the film 60 with a lower melt index ethylene hexene copolymer. It may be used instead of coalescing.

  The film selected to make the container of the present invention is preferably biaxially stretched by the well-known blown or double bubble technique, for example, as described in Pahlke US Pat. No. 3,456,044. In this technique, an extruded first tube leaving a tube extrusion die is cooled, folded, and then biaxially stretched, preferably by reheating and re-expanding, to form a second bubble. The film is preferably biaxially stretched, in which case the transverse (TD) stretching is achieved by inflation so as to easily expand the heated film. The machine direction (MD) stretching is preferably accomplished using nip rolls that rotate at different speeds to pull or stretch the film tube in the machine direction.

  The draw ratio of the biaxial stretching to form the bag material is preferably sufficient to give the film a total thickness of about 1.5 to 3.5 mils. The MD draw ratio is typically 3: 1 to 5: 1, and the TD draw ratio is also typically 3: 1 to 5: 1.

  Referring now to FIG. 8, a double bubble or inflation process is shown. The polymer blends that make up several layers are co-extruded by conveying separate melt streams 311a, 311b and 311c to die 330. These polymer melts adhere to each other and are co-extruded from annular die 330 as multilayer tubes 332 with relatively thick walls. This thick-walled first tube 332 leaving the extrusion die is cooled and collapsed by a nip roller 331, and the collapsed first tube 332 is drawn through the tube 332 by transport rollers 333a and 333b. The second bubble 334 is conveyed to a reheating zone that reheats to below the melting point of the layer and is expanded with a confined fluid, preferably a gas, more preferably air. The second bubble is formed by fluid confined between a first pair of nip rollers at one end of the bubble and a second pair of nip rollers at the opposite end of the bubble. You. Inflation, which causes the film to expand radially, gives a transverse (TD) stretch. Stretching in the machine direction (MD) is achieved by adjusting the relative speed and / or dimensions of nip roller 336 and nip roller 337 to stretch (draw) the film in the machine direction. Rollers 337 also fold the bubbles to form a stretched film 338 in a lay flat, which may be wrapped or slit on reel 339 to break off further processing.

  Biaxial stretching is preferably from about 1.25 to about 8.0 mils, preferably 1.5 to 4 mils, more preferably 1.75 to 3.0 mils (44 to 76 μm), and even more preferably, a multilayer film. Is sufficient to give a total thickness of 2.5 mils.

  Preferred films for use in making bags according to the present invention and methods of making suitable films therefor are described in U.S. patent application Ser. No. 09 / 401,692, filed Sep. 22, 1999 (see "Breaking No. 09 / 431,931 filed on Nov. 1, 1999 (“High Shrinkage Film with Blending Resistance, Blend and Manufacturing Method”) and filed on Jul. 6, 2000. No. 09/611192, entitled "Ionomer Fracture-Resistant Thermoplastic Patch Bags, Films, Blends, and Methods of Making."

  The procedure is similar for monolayer films, except that the first tube is manufactured using a single screw extruder (or a multi-screw extruder that passes the same polymer formulation), and the biaxial stretching is performed. Is sufficient to provide a monolayer film preferably having a total thickness of 2 to 6 mils or more, typically about 3.5 to 4.5 mils, and generally, MD and It is in the same range as the draw ratio discussed above for both TDs, ie, about 3: 1 to 5: 1.

  Although not essential, it is preferred to irradiate the film with radiation to extend the range of heat sealing and / or to improve the toughness of the inner and outer layers by radiation induced crosslinking and / or splitting. This is preferably achieved by irradiation with an electron beam at a dose level in the range of at least 2 megarads (MR), preferably in the range of 3 to 5 MR, but for thicker films, for example, higher doses may be used. Good. Irradiation is provided to the first tube or after biaxial stretching. The latter, called post-irradiation, is preferred and is described in Lustig et al., US Pat. No. 4,737,391. See if desired.

  After stretching, the tubular film 338 is folded, slit longitudinally, flattened, and wound on a reel 339 for use as a web. One of skill in the art will appreciate that the above methods can be used to form a film, that the film can be made by conventional single blown film methods, and that stretched or unstretched sheets can be stretched or widthed to provide orientation. It will be appreciated that it can be produced by slot casting sheet extrusion without dipping. Further, those skilled in the art will recognize that the flat width of the collapsed tube will determine the width of the resulting sheet film. Thus, the dimensions of the first tube and subsequent processing can be selected to provide the maximum flat width and film thickness for the desired application, thereby advantageously maximizing the production capacity of the film production equipment. Can be changed.

  Advantageously, the bag manufacturer adjusts the width of the sheet from the film web to various lengths and widths of the bag (by slitting or cutting the web to the desired width) and to the specific bag or web. It can be manufactured by adjusting the distance between the lateral end seal and the mouth of the bag for a series of bags. This eliminates the costly need to manufacture seamless tubes of a particular width that are widely used by butchers in recent years. The present invention also provides cost savings and manufacturing efficiencies by producing multiple width and length bags from standard web materials manufactured using substantially 100% of the capacity of the film manufacturing equipment. Enable. This reduces the need to overstock any and all seamless tube webs having different widths. The bag manufacturer simply forms a continuous tube member by slitting the film web to the desired width and longitudinally sealing opposing side edges as described for bags 10, 110 and 210. Is fine. Adjustable length bags can be made by laterally sealing the tube member and slitting the tube member at a location spaced from the lateral seal. In addition, the film is formed such that the opposite side edges of the film are vertically adhered to each other to form a continuous tube member, the continuous tube member is folded, and the folded continuous tube member is reeled. It can also be made into a winding material of a continuous tube member by winding. The roll of continuous tube member is then provided to a food processor, who then forms individual bags, such as bags 10, 110 and 210. The winding of such a continuous tube member may have a folding diameter of up to 20 inches, preferably 20 inches or more, more preferably 22 inches or more.

  Preferably, bag making is a continuous process in which the film is directed to a bag making assembly (not shown) where individual end seal bags are made. As mentioned above, the web can be slit to the desired width, and the unused portion can be rewound for subsequent use. The bag is formed by continuously joining the opposite side edges of the film to one another and forming a heat seal such as a wrap seal or fin seal to form a continuous tube member, and then at predetermined intervals across the width of the tube member. It is manufactured by laterally heat sealing and welding the first and second walls of the tube member together. The tube member is preferably cut at the same time as or during the same step of heat sealing transversely to form a bag as shown in FIG. 1, 3 or 5. Typically, when a transverse seal is made for one bag, a transverse cut forming the mouth of an adjacent bag is being made. This method uses a bottom edge formed by the lateral heat seal when flattened, an opening formed by the cut edge, and a fold that occurs when the tube member is flattened. A so-called "end-seal" bag is formed having two side edges formed. A transverse heat seal should be applied over the entire tubing to ensure an airtight closure. Each bag being formed from one tube member is necessarily formed by at least two usually parallel spaced transverse cuts (resulting in a segment of the tube member), and Normally, a transverse seal adjacent to one of these cuts will define the bottom of the bag located opposite the bag opening formed by the farthest cut. In a typical manufacturing process, the tube member is laterally sealed, and an adjacent transverse cut is made as part of the same process, and the seal and adjacent cut are combined in a single bag. Since the same cut also forms an opening for an adjacent pouch while forming a seal end for the adjacent pouch, the adjacent pouch can be referred to as a far cut. The spacing between the transverse seal and the cutting point may be varied and will determine the length of the bag formed. The length of the bag can be easily changed by changing the spacing between the cuts. Also, the width of the bag can be easily changed by changing the width of the film by slitting the standard winding material. In another embodiment of the present invention, the cuts and seals can be made alternately and spaced apart from each other to form a two-piece, connected bag in saddleback format.

  The present invention advantageously provides a method of making a heat shrinkable bag that allows a bag manufacturer to produce multiple bag dimensions (different lengths and widths) from a single film stock dimension, Can advantageously maximize film production efficiency by eliminating the need to produce seamless tubes of different widths. In other words, the present invention allows bag manufacturers to produce one standard width sheet film stock, such as 86, 94, 98, 104, 112, 126, 162 inches or more, depending on the capabilities of the film making equipment. Make it possible to do The standard sheet film stock can then be slit to the desired width, forming a bag as described herein, and the remaining portion of the sheet film stock re-wrapped for later use in another job. it can. Prior art bags reduce manufacturing efficiency because they require the manufacturer to manufacture different seamless tube dimensions for each size of bag to be manufactured.

Except where otherwise noted, the following physical properties are used to describe the films and seals of the present invention. These properties are measured either by the test procedures described below or by tests similar to the following methods.
Average gauge: ASTM D-2103
Tensile strength: ASTM D-882, Method A
1% secant modulus: ASTM D-882, Method A
Oxygen gas permeability (O 2 GTR): ASTM D-3985-81
Elongation at break: ASTM D-882, Method A
Molecular weight distribution: gel permeation chromatography Gloss: ASTM D-2457, angle 45 °
Haze: ASTM D-1003-52
Melt index: ASTM D-1238, Condition E (190 ° C.) (excluding propene-based (> 50% C 3 content) polymers tested under Condition L (230 ° C.))
Melting point: ASTM D-3418, peak determined by DSC at a heating rate of 10 ° C./min. p
Vicat softening point (Vsp): ASTM D-1525-82
Seal strength: ASTM F88-94.
All ASTM test methods described herein are incorporated by reference into this disclosure.

Shrinkage value :
Shrinkage values are obtained by measuring the unrestricted shrinkage of a 10 cm 2 sample immersed in water at 90 ° C. (or the indicated temperature if different) for 10 seconds. Four specimens are cut from a given sample of the film to be tested. The test specimen is cut into a square of 10 cm length (MD) × 10 cm length (TD). Each specimen is completely immersed in a water bath at 90 ° C. (or the indicated temperature if different) for 10 seconds. Next, the test piece is removed from the water bath, and the distance between the sides of the contracted test piece is measured in both the MD and TD directions. The difference between the measured distance of the contracted test piece and each of the original 10 cm sides is multiplied by 10 to obtain the contraction rate in each direction. Average the shrinkage of the four specimens and report the average MD and TD shrinkage values. The term “heat-shrinkable film at 90 ° C.” means a film that has an unlimited shrinkage value of at least 10% in at least one direction.

Five identical samples of tensile seal strength (seal strength) test film are 1 inch (2.54 cm) wide and a length suitable for the test equipment, eg, about 5 inches (12.7 cm) long. Then, the seal portion having a width of 1 inch (2.54 cm) is disposed centrally and laterally. The opposing parts of the film sample are secured to opposing clamps of a universal tensile test instrument. The film is secured between the clamps by a taut sliding fit without stretching before the start of the test. The test is performed at ambient or room temperature (RT) (about 23 ° C.) test temperature. The instrument was operated to break the film at a constant rate of 12.0 inches per minute (30.48 cm) through a clamp beside the seal (breakage or delamination of the film or seal and delamination and film breakage). (Loss of integrity). The indicated test temperature and 1 bs. The force at break is measured and recorded. This test is repeated for four additional samples and the average gram at break is reported.

Ram Rupture Test The ram rupture test is used to determine the maximum breaking load or breaking force and the maximum breaking stress of a flexible film when hit with a hemispherical or spherical hammer. This test gives a quantitative measure of the fracture resistance of thin plastic films. This test is further described in US patent application Ser. No. 09 / 401,692.

  The following examples are provided to illustrate the present invention and should not be construed as limiting the invention set forth in the appended claims.

  In the following examples, film compositions were prepared using the apparatus and methods generally described in US Pat. Was. All layers were extruded as a first tube, which was cooled at the same time as exiting the die, for example by injection with tap water. This first tube is then concentrically circumscribed around the moving first tube by a radiant heater (although other means known to those skilled in the art such as conduction or convection heating may be used). It was reheated with further heating to the stretching temperature for the biaxial stretching achieved by the heated air cushion in a lateral flow through the heated porous tubing. Cooling was achieved by means of a coaxial air ring. Stretch point temperatures, bubble heating and cooling rates, and stretch ratios were generally adjusted to maximize bubble stability and throughput for the desired amount of stretching or stretching. All percentages are by weight unless otherwise indicated.

Example 1
As generally illustrated in FIGS. 1 and 2, a co-extruded tri-layer biaxial stretch shrink with a (A) internal heat-sealable layer, (B) a barrier layer and (C) an outer layer is provided for a puncture resistant bag according to the invention. It was manufactured from a film consisting of a film. The inner and outer layers are directly bonded to opposing sides of the barrier layer. The three layers contained the following composition:
(A) 33% by weight of EXACT4053, 37% of ESCOLINE LD701. ID, 24% SCLAIR 10B, 4% Spartech A27023 and 2% Spartech A32434,
(B) a blend of about 85% vinylidene chloride-vinyl chloride copolymer and about 15% vinylidene chloride-methacrylate copolymer; and (C) 33% EXACT 4053% by weight, 25% SCLAIR 10B, 40% ESCOLINE LD 701. . ID and 2% Ampacet 501236.

  One extruder was used for each layer. Each extruder was connected to an annular co-extrusion die where the thermoplastic resin was co-extruded to form a first tube. The resin mixture for each layer was fed from a hopper to an attached single screw extruder where the mixture was thermoplasticized and extruded from a three-layer coextrusion die into a first tube. The extruder barrel temperature for the barrier layer (B) is about 250-300 ° F (121-149 ° C), and for the inner layer (A) and outer layer (C) is about 290-330 ° F (143-140 ° C). 165 ° C). The temperature distribution of the co-extrusion die was set at about 320-350 ° F (163-117 ° C). The extruded multilayer first tube was cooled to 50-68 ° F (about 10-20 ° C) by injection with cooling tap water.

  A cooled first tube of about 4 inches (10.16 cm) flat width was made through a pair of nip rollers. The cooled flat first tube is expanded, reheated, biaxially stretched, and cooled again to produce a biaxially stretched film, which is slit open and flattened to approximately 16 inches (40 inches). (.64 cm) width and was wound on a reel. The MD draw ratio was about 5: 1 and the TD draw ratio was about 4: 1. The stretching point or temperature is below the main melting point for each layer stretched and above the main glass transition point of those layers, which is believed to be about 68-85 ° C. The resulting biaxially stretched film had an average gauge of about 2.5 mils and had a nice appearance.

  The film was irradiated at a dose level of about 5.0 MR. As described above, it is preferable, but not essential, to irradiate the entire film with radiation to broaden the range of heat sealing by radiation-induced crosslinking and / or cutting and / or to improve the toughness of the inner and outer layers. . Irradiation can be performed in the first tube or after biaxial stretching. The latter, called post-irradiation, is preferred and is described in Lustig et al., US Pat. No. 4,737,391. See if desired. The advantage of post-irradiation is that a relatively thin film is processed instead of a relatively thick first tube, thereby reducing the power required for a given processing level.

  The film was rewound and slit to a width of 13 inches (33.02 cm). The film was then sent to a bag making machine to form a tube member having a continuous longitudinally extending wrap seal. A bag according to bag 10 shown in FIG. 1 was formed by sealing transversely across the tube member and simultaneously separating the sealed portion from the continuous tube structure.

  Various tests were performed on the film and / or the resulting inventive bag. The film thickness was determined to average 2.1 mils. The lap seal was tested and found to have a very strong average seal strength of about 8000 to 10000 grams. The bag also had an average MD and TD heat shrinkage at 90 ° C. of 48 and 48, respectively. The results of the ram destruction were equally impressive. The 2.1 mil film was measured for breaking resistance and had a maximum breaking force of 86 Newtons (N) and a total energy loss of 0.9 Joules (J). This preferred bag has very good heat shrinkage and very good puncture resistance which is very desirable for packaging raw red meat fillets. Accordingly, a heat shrink sack has been made that is economical to manufacture, has a puncture resistant and strong seal, and has a unique combination of previously unknown features and commercial advantages.

  Advantageously, bags 10 and 110 can be made economically from approximate shapes, as these bags 10 and 110 are not formed from seamless tubes that must be made to the desired width. The only limitation on the size of the bag made is the size of the stock sheet film that is wide enough to meet the specifications. Standard web sheet films are available in widths greater than 100 inches (254 cm). The present invention allows a bag manufacturer to produce bags of any size from flat sheets of any size web, up to the size limit of the web. For example, if the web is 52 inches wide, a tube member having a fold diameter of approximately 26 inches can be made, excluding the amount of overlap or contact of the first seal 16 or 116 used. If the manufacturer wants to make a bag with a folding diameter of 18 inches, then the manufacturer can reduce the standard webbing to the appropriate width (plus the extra for the area of the first seal 16 or 116). Slit to approximately 36 inches). The unused portion of the slit forms a standard web that can be re-wound for use in producing bags of another size. In this embodiment, a standard webbing film can be produced more economically. This is because film production equipment can operate at or near the upper limit of film width production, so that almost all of the capabilities of this equipment can be used. Manufacturing bags from seamless tubes requires that the film apparatus be operated with limited capability to form tubes of different small widths. In addition, film production equipment requires costly equipment and breaks between operations of different dimensions which significantly increase the cost of producing seamless tubes.

  A preferred embodiment of the heat-shrinkable packaging of the present invention is made from a sheet 410 of heat-shrinkable film 411, which comprises a first edge 412a and an opposite second edge 412b. These are connected by a third edge 412c and a fourth edge 412d. The first edge 412a and the second edge 412b are preferably parallel to each other when the film 411 is in a long, flat, planar state. The third edge 412c and the fourth edge 412d are preferably parallel to each other when the film 411 is in a lay flat planar state. Also, the first edge 412a and the second edge 412b are preferably perpendicular to the third edge 412c and the fourth edge 412d when the film 411 is in a lay flat plane state. is there. The film 411 has four corners at the intersections of the four sides. These corners are a first corner 412ac determined by a contact point between the first edge portion 412a and the third edge portion 412c, a second corner 412bc determined by a contact point between the second edge portion 412b and the third edge portion 412c, The third corner 412ad is determined by the contact point between the first edge 412a and the fourth edge 412d, and the fourth corner 412bd is determined by the contact point between the second edge 412b and the fourth edge 412d. The film 411 has a top surface 413a surrounded by a perimeter 414 formed by sides 412a, 412c, 412b, and 412d, and an opposite bottom surface 413b surrounded by the perimeter 414. FIG. 10 illustrates a corner 412ad of the film 411 turned up to reveal the bottom surface 413b.

  Referring now to FIG. 11, a preferred embodiment of the present invention is shown generally as a bag 415 made from the film 411 of FIG. The bag 415 overlaps the first edge 412a with the second edge 412b, and is preferably sealed with heat and spaced apart in parallel by dotted lines 417a and 417b and third edge 412c and fourth edge 412c. It is formed by creating a fused wrap seal 416 that is determined by the edge 412d. Although the wrap seal 416 is shown as a continuous elongated rectangle extending from side 412c to side 412d, the present invention allows the shape of the seal to be varied and, for example, a wavy or zigzag shape or other as desired. Note that it is further intended that the shape can be formed. Also, the width of the seal can be varied as desired to be even thicker or thinner. Also, the seal may optionally be made by alternative or additional means, including, for example, by the application of a suitable heat tube or adhesive material known in the art for sealing the films to one another. The wrap seal 416 is shown as a continuous wrap seal 416 suitable for forming a hermetic package, but for some applications, such as certain industrial or preservative goods, such as wavy or dotted lines It is further contemplated that a discontinuous seal having the appearance of can be used. Examples of this intermittent seal are when applying a vacuum, or sealing with trapped air or other gas bubbles, or removing air by other means is undesirable. Allows air to escape from the closed container during the packaging operation. Optionally, one of ordinary skill in the art, in light of the teachings of the present application, changes the strength of the seal to the shape, thickness, continuity or intermittentness of the seal, the type of seal material selection and the strength of different types of seals. It can be varied by the choice of the aforementioned parameters, such as the well-known parameters for, for example, by adjusting the dwell time or temperature to effect heat sealing. Such changes and adjustments can be made by one skilled in the art without undue experimentation.

  Referring again to FIG. 11, the wrap seal 416 is preferably a heat seal that forms a weld between the top surface 413a and the bottom surface 413b of the film 411. This overlap-sealed film 411 defines a tube member 418, where the top surface 413 a of the film 411 forms the inner film surface 419 of the tube member 418. The second seal 420 extends laterally across the tube member 418 adjacent the third edge 412c of the film 411, thereby forming a sealed bag end 421. Various seals can be used. Preferably, the second seal 420 will be a heat seal that fuses the interior surface 419 of the bag film to itself. A second seal 420 near the sealed bag edge 421 forms both the first bag edge 422 and the opposite second bag edge 423, and the second seal extends over the tube member 418 through the first bag It extends from the edge 422 to the second bag edge 423. Further, as with the wrap seal 416 described above, various shapes, thicknesses, structures, and the like can be used for the second seal. The wrap seal need not be centrally located between edges 422 and 423, but is preferably located somewhere between them.

  On the opposite side of the sealed bag edge 421, there is a bag frame formed by the wrap-sealed film based on the fourth edge 412d, through which the tube member 418, the sealed bag edge 421, and the bag mouth are provided. A product (not shown) can be placed in a product storage chamber 425 defined by section 424. The first bag edge 422 extends from the first bag end corner 426 so that the bag 415 can be folded into a lay flat having a first bag edge 422 and a second bag edge 423 on the opposite side. A first bag mouth point 427 can extend and a second bag edge 423 can extend from a second bag end corner 428 to a second bag mouth point 429. In a lay flat state or a state close to a lay flat as shown in FIG. 11, the bag end 421, the bag mouth 424, and the first bag edge 422 and the second bag edge 423 connected to the bag end 421, A first bladder wall 430 and an opposite bladder wall 431 connected thereto are defined. Tube member 418 has an inner surface 419 and an outer surface 433. The first bag wall portion 430 has a first bag wall portion first surface 430a near the second side edge portion 412b and extending to the second bag edge portion 423. The first bag wall portion 430 also has an opposite first bag wall portion joint surface 430b near the first edge portion 412a and extending to the first bag edge portion 422.

  Preferably, the second seal 420 is such that the first seal 416 is located within one of the first bladder wall 430 and the second bladder wall 431, thereby forming a "back seam" of the bladder. Provided in an appropriate manner. This provides one seamless sack wall and two seamless sack edges that can contain printed graphics applied to the film before or after the bag is formed. In addition, the second seal 420 can have any shape, whether straight or curved, as long as the second seal 420 acts to seal the end 421. At least one of the first seal 416 and the second seal 420 is a peelable seal. As used herein, "peelable seal" (and similar terms) refers to an uncontrolled or uncontrolled amount of packaging material that can cause premature breakage of the package and / or inadvertent contamination or spillage of the contents of the package. A seal, especially a heat seal, designed to be easily peelable without random tearing or bursting. The peelable seal is such that the package can be peeled by hand to open the package at its seal without tearing or bursting the package with a knife or other instrument. In the present invention, the peelable seal must have sufficient seal strength to prevent the seal from breaking during the standard heat shrink process of the packaged article and even during standard shipping and shipping. . Also, the seal strength must be weak enough to allow manual opening of the seal. Preferably, seal parameters such as material and seal condition selection are used to adjust the seal strength to the desired level for a particular package and application.

Many different peelable seals are known in the art, and are suitable for use in the present invention. Peelable seals are generally made from a thermoplastic film that incorporates a peelable system therein. Suitable strippable films and / or strippable systems are described in US Pat. Nos. 4,944,409 (Busche et al.), 4,875,587 (Lulham et al.), 3,655,503 (Stanley et al.), And 4,058,632 (Evans et al.). No. 4,252,846 (Romesberg et al.), No. 4,615,926 (Hsu et al.), No. 4,666,778 (Hwo), No. 4,784,885 (Carespodi), No. 4,882,229 (Hwo), No. 6,476,137 (Longo). No. 5,997,968 (Dries et al.), No. 4,189,519 (Ticknor), No. 5,447,752 (Yanidis), No. 5,128,414 (Hwo), No. 5,023,121 (Pocket et al.), No. 4,937,139 (Genske). Other), No. 916190 (Hwo) and ibid. No. 4,550,141 disclosed (Hoh). Please refer to these if desired. Preferred films for use in making bags according to the present invention can be selected from multilayer heat shrinkable films capable of forming a peelable seal. Preferred films also include high puncture resistance (eg, as measured by ram and / or hot water puncture tests), high shrinkage values, low haze, high gloss, high seal strength, and printability. One or more of the above properties or all advantageous combinations thereof may also be provided. The bag of the present invention advantageously uses a thermoplastic film that includes an oxygen and / or moisture barrier as it can be used to hold oxygen or moisture sensitive articles such as food after deflation and sealing. Is preferred. As used herein, the term "barrier" or "barrier layer" refers to a layer of a multilayer film that acts as a physical barrier to moisture or oxygen molecules. An advantageous combination of barrier layer material and other film layers for packaging oxygen-sensitive products such as raw red meat is 70 cc / hr within 24 hours at 73 ° F (23 ° C) at 1 atmosphere. It will provide an oxygen gas permeability (O 2 GTR) of less than square meters (preferably less than 45, more preferably less than 15) and a relative humidity of 0%.

In another embodiment, the gas permeability is controlled to allow CO 2 to escape for packaging respirable food products such as cheese, as described in US Pat. No. 6,511,688. Preferably, the film has an unlimited shrinkage at 90 ° C in at least one direction, preferably at least 20% (preferably at least 35%) in both the machine direction (MD) and the transverse direction (TD). Unrestricted (sometimes called "free") shrinkage is measured by cutting a square film piece measuring 10 cm in each of the longitudinal and transverse directions. This film is immersed in water at 90 ° C. for 5 seconds. After removal from the water, the pieces are measured and the difference from each of the original dimensions is multiplied by 10 to obtain the shrinkage in each direction.

  Oxygen barrier materials that can be included in the films used for the bags of the present invention include ethylene vinyl alcohol copolymer (EVOH), polyacrylonitrile, polyamide, and vinylidene chloride copolymer (PVDC). For some applications, nylon provides useful oxygen barrier properties, especially at low temperatures, such as used in frozen foods. Preferred oxygen-barrier polymers for use in the present invention are vinylidene chloride copolymers or copolymers of vinylidene chloride with various comonomers, such as copolymers with vinyl chloride (VC / VDC copolymer) or acrylic. Copolymers with methyl acid (MA / VDC copolymer) and EVOH. A particularly preferred barrier layer comprises about 85% vinylidene chloride-methyl acrylate copolymer and about 15% vinylidene chloride-vinyl chloride copolymer, as described, for example, in U.S. Pat. No. 4,798,751 to Schutz et al. . Suitable and preferred EVOH copolymers are described in U.S. Pat. No. 5,759,648. Please refer to these patent specifications if desired.

  A variety of peelable films and peelable seal systems can be used in the present invention. In a preferred embodiment, at least three layers (one or more hybrids described below) comprising an outer layer, an inner heat seal layer, and a tie layer disposed between the outer layer and the inner heat seal layer A film is used which consists of a coextrudate of a system which uses a sealing layer (referred to as a three-layer strippable system to distinguish it from the system). In an embodiment of this preferred three layer system, the film layers are such that delamination occurs by breaking apart the tie layer and / or the bond between the tie layer and at least one of the outer and inner layers. Selected. A durable bond, a peelable bond, and a breakable bond are, for example, two adjacent first and second layers having materials that are more compatible with each other compared to the second layer. And by providing an adjacent third layer that establishes a relatively durable bond between these layers when the two materials have a lower affinity for each other, can be incorporated into the coextrusion process. This three-layer structure may be between a first layer and a second layer (which have a higher affinity for each other than the second layer) or between a third layer having a lower affinity (in this case the second layer is (Common to both the first and third layers as a tie layer or tie layer) to establish a relatively durable bond. Thus, the low affinity between the second and third layers for the first and second layers causes a relatively strippable bond between the second and third layers. The choice of various materials determines the nature of the bond, ie, whether it is durable, peelable, breakable, or a combination thereof.

Suitable polymers for use in the outer, tie, and inner heat sealable layers include both poly-type materials such as ethylene homopolymers and copolymers and ionomer-type materials. Examples of suitable polymers include ethylene vinyl acetate copolymer (EVA), ethylene α-olefin copolymer, linear low density polyethylene, low density polyethylene, very low density polyethylene (VLDPE), neutralized ethylene / acid Copolymers, plastomers, ethylene acrylate copolymers, ethylene methyl acrylate copolymers and zinc or sodium salts of partially or completely neutralized ethylene methacrylic acid copolymers are mentioned. The inner heat seal layer advantageously uses a heat sealable material. The tie layer is selected to have a relatively low peel strength when releasably bonded to either the outer layer or the inner heat seal layer. Tie layer is typically about 5-30% polybutylene and another component, such as ethylene vinyl acetate copolymer, ethylene copolymers with α- olefin C 4 -C 8, linear low density polyethylene , Ionomers, neutralized ethylene / acid copolymers or unneutralized ethylene / acid copolymers and blends with mixtures of two or more thereof. As used herein, the term "polybutylene" includes polymer units derived from 1-butane as the major component (75% polymer units), preferably at least one of the polymer units. 80% include those derived from 1-butane. A preferred polybutylene is reportedly having a density of 0.908 g / cm 3 , a melt index of 1.0 g / 10 min, and a melting point of 243 ° F., and is sold under the brand name PB8640 under the name of Basel Polyolefins, Inc. It is a random copolymer of 1-butene and ethylene available from a Japanese corporation. In this preferred strippable embodiment, is the heat seal formed between the inner heat seal layer and another layer to be heat sealed a part of another film or of the same film? Regardless, they should have a permanent, ie, greater, seal strength than the peelable bond between the tie layer and one of its adjacent layers. The preferred three-layer coextrusion peelable structure described above contemplates optional additional layers for producing films of four, five, six, seven, eight, nine, ten or more layers. One or more additional layers can be coextruded with or separately from the above three layers, and multilayer film structures can be formed by coextrusion as well as well known in the art such as coating lamination, adhesive lamination, or combinations thereof. It is further contemplated that they can be formed by other methods.

  It is also contemplated that one or more such additional layers can be adjacent to or between any of the three layers. In one embodiment of the present invention, a durable adhesive that may or may not be applied in a heated or molten state, liquid state, or other state may be used in place of the heat seal layer. However, it is preferred to use a heat-sealable layer.

  It is also contemplated that a peelable seal using one or more so-called "hybrid" surface layers can be used (in this case, peeling occurs at the seal layer interface 432 rather than at the inner layer of the film 411). . This type of release system can be used, for example, to control the diffusive properties that provide high seal strength in a desirable low form for release, as well as under conditions that can adversely affect seal integrity, such as certain types of packaging. The article of the present invention adheres to particulates, starches, fats, greases or other ingredients that can reduce the seal strength or impair the ability to provide the desired strength of the seal, for example, a strong hermetic seal by heat sealing. There are disadvantages associated with the problem of sealing underneath. Such a seal system is often referred to as a two-layer release system, but its film structure may include three, four, five, six, seven, eight, nine, ten or more layers.

  A preferred peelable seal film and peelable seal system is disclosed in U.S. Pat. No. 4,944,409, entitled "Easy Open Package". See if desired.

A preferred multilayer barrier film structure for use in manufacturing a bag according to the present invention is illustrated in FIG. 12, which is an enlargement of a first seal 416 made from a sheet of the heat shrinkable film 411 of FIG. FIG. 3 shows an end view. The thicknesses of the layers in FIG. 12 and the other figures shown herein are not to scale, but are drawn to specific dimensions for ease of illustration. The preferred easily peelable heat shrinkable film 411 is a five layer coextrudate and includes from the inner surface 419 of the tube member 419 (see FIG. 11) to the opposite outer surface 433.
(A) the heat sealable layer 434 on the inner surface preferably comprises a blend of ethylene vinyl acetate (EVA) and polyethylene;
(B) the barrier layer 435 preferably comprises a vinylidene chloride copolymer (PVDC);
(C) the core layer 436 preferably comprises a blend of EVA and polyethylene;
(D) tie layer 437 preferably comprises a blend of polyethylene and polybutylene;
(E) The heat-sealable layer 438 on the outer surface is preferably made of polyethylene.

  The thickness of each layer, based on the total thickness of the film 411, is typically <50% for the inner surface heat sealable layer 434, <20% for the barrier layer 435, and <28% for the core layer 436. , The tie layer 437 may be <15% and the external heat sealable layer 438 may be <15%. The first seal 416 heat seals the inner film surface 419 of the film 411 to the outer film surface 433 longitudinally along their respective lengths such that the inner film surface 419 and the outer film surface 433 overlap. Made by. In this embodiment, fusion occurs between the inner surface heat sealable layer 434 and the outer surface heat sealable layer 438. The peelable bond of the system is provided by a tie layer 437 and there, for example, at the tie layer interface with the outer surface heat sealable layer 438 and / or at the tie layer interface with the core layer 436, and / or Alternatively, separation occurs between the outer layer 438 and the core layer 436. Thus, referring to FIGS. 11 and 12, the strippable portion of the film is outside the tube member 418, but this is preferred. This is because the first seal 416 is peelable, while the second seal 420 and the last hermetic seal (not shown) are strong between the inner surface heat-sealable layers 434 of the respective bladder walls 430 and 431. Will ensure that it is a good fusion seal.

  Referring to FIG. 13, a partial cross-sectional view taken along line BB of FIG. 11 shows how a preferred embodiment of the present invention allows a lap seal to function as an easy-open peel seal while at the same time having a strong end seal. Functioning to cause the following. In FIG. 13, the film 411 has an outer surface 433 with an outer surface layer 438, a tie layer 437, a core layer 436, a barrier layer 435, and an inner heat-sealable layer 434 that are continuous layers therefrom. Referring to FIG. 11, a second seal 420 is provided over the tube member 418, the surface 419 of which is collapsed by itself. Referring again to FIG. 13, the seal has an internal surface heat-sealable layer 434 adhered thereto with the peelable tie layer 437 located far from the end seal interface 439. The preferred embodiment of the present invention shown in FIGS. 11-13 includes (a) an end seal that bonds similar materials having strong sealing properties to one another while holding the easily peelable tie layer 437 away. (B) Combines an external surface heat sealable layer 438 and a wrap seal having a peelable tie layer 437 near the wrap seal interface 432, thereby easily peeling into bags or packaging materials made using the above arrangement. Give a possible opening.

  Film 411 is designed to control film breakage when peeled by hand. Due to the composition of the strippable tie layer 437, its location near the lap seal interface 432, and in the case of the preferred three layer strippable system the outer surface heat sealable layer 438, the second edge Initial tearing or tearing begins when the portion 417b is manually pulled apart over the wrap seal 416. This tear propagates from the heat seal at the edge 417b of the lap seal interface 432 to its outer heat sealable layer 438. If a peelable bond is designed to occur at the tie layer 437, continuous application of the opening force will result in the tie layer 437 / outside until the tear reaches the opposite edge 417a of the heat seal 416. Causing delamination or destruction of the adhesive layer along the interface of the heat sealable layer 438 or along the interface of the tie layer 437 / core layer 436 and / or causing the tie layer 437 to break, or These are caused together, where the tear spreads over the outer layer 438 to either the edge 412a or the back, thereby opening the bag.

  In general, the films used in the heat shrinkable bags of the present invention will have properties that are desirable for certain packaging operations using the films, such as peelable seals, puncture resistance, modulus, seal strength, barrier properties. Can have any desired thickness as long as it has a thickness and composition sufficient to provide optical properties and the like. For material efficiency and protection, it is desirable to use the maximum film thickness to provide the required puncture resistance and other properties. Preferably, the film has a total thickness of about 1.25 to about 8.0 mils, more preferably, about 1.75 to about 3.0 mils.

  Another embodiment of the present invention is illustrated in FIGS. 14 and 15 generally as a bag 415a. The same reference numerals found in bag 415 are used for bag 415a. The bag 415a further includes a tension flap 440. This tension flap 440 provides additional overlap by moving the first edge 412a and the second edge 412b further apart, and yet outside of the product storage chamber 425 on the second side of the first bag wall. A portion of the first side 430a of the first bag wall overlapping the portion 430b is formed by positioning the first wrap seal 416 such that the first side 430a is not sealed to the second side 430b. This tension flap 440 allows the end user to easily grip and pull the packaging material without taking the means of a cutting instrument often required when opening packaging material that does not have a peelable system. The product can be easily opened. Although shown to extend the entire length of the bag 415a, those skilled in the art will be able to cut the tension flap 440 into the desired shape or any other well-known that is known to assist in initiating peeling. You will recognize that the mechanism of can be adopted. The preferred films illustrated in FIGS. 10, 12, and 13 described above are also preferred for use in the bag 415a.

  In another embodiment illustrated in FIGS. 14 and 15, the positions of the bag mouth 424 and the second seal 420 in FIG. 11 are reversed, which is shown in FIG. Is represented.

  Referring to FIG. 16, an example of the second seal 420 a shown in a cross-sectional view is that the first bag wall portion is sealed from the first bag edge portion 422 to the second bag wall portion 431 of the second bag wall portion 423, It is shown that the first wrap seal located between the first edge 412a and the second edge 412b is sealed. In known heat sealing methods, opposing sealing rods or wires press the layers of film together at elevated temperature and pressure for a time sufficient to cause fusion between the layers. These heat sealing rods can be rigid and / or flexible, but generally they are not flexible or flexible enough to seal the film. As shown in FIG. 16, the second seal 420a has a seal boundary surface 439a, and the boundary surface 439a is close to the first edge 412a and the second edge 412b and the seal pressure is reduced. There are two possible points that can decrease during operation. That is, the seal pressure may decrease at point 441 below edge 412b of second seal interface 439a, and may decrease at point 442 adjacent first edge 412a. It is also assumed that a void (gap) may exist at the point 442, for example. In order to produce the desired strong seal, especially at points 411 and 422, and all along the second seal interface 439a, seal parameters such as pressure, temperature, dwell time and composition of the heat sealable layer are desired. Can be adjusted. In particular, it has been found that the use of a high melt flow index polymer component in the heat seal layer is advantageous for filling potential voids. It may also be advantageous to taper one or both edges 412a and 412b to increase the contact surface and / or pressure between overlapping films, particularly at points 441 and 442 and adjacent areas.

  Another embodiment of the present invention is illustrated in FIG. 17 generally as a bag 415b. Also, like elements include like reference numerals. The bag 415b includes a first fin seal 516, which contacts the first side 430a and the second side 430b of the bag wall 430 with the internal film surface 419 on each side facing each other, It is coupled to have a seal boundary surface 517. One or both of the first edge 412a and the second edge 412b may extend outward beyond the first fin seal interface 517 such that a tension flap (not shown) is provided. Bag 415a (FIG. 14) is preferred over bag 415b. Because the plane of the first seal 416 is parallel to the plane of the shrink force encountered during the heat shrink process. The first fin seal 516 of the bag 415b positions its heat seal plane perpendicular to the shrinking force (as indicated by arrows Z ′ and Z ″ in FIG. 19), which is Increases the risk of seal breakage (premature peeling) during the process. Further, since the containers of the present invention are advantageously made from a single film sheet or web, the arrangement of the fin seals, such as the first seal 516, is such that each seal of the container is a peelable seal. Need to be. Also, the second seal 420 and the last hermetic seal (not shown) are necessarily peelable. This is because the first bag wall portion 430a and the second bag wall portion 430b are sealed with their films in the same contact relationship. For example, FIG. 19 is an enlarged view of the first fin seal 516 shown in cross section showing the individual layers of the preferred film discussed above with respect to bags 415 and 415a. Each wall 450 and 452 of the seal 516 includes a three-layer strippable system (tie layer 437) equidistant from and near the seal interface of the sealant layer 438. Thus, not only can it not be predetermined that a peel failure will occur at the wall 450 or 452, but also all seals will be easily peeled, and the direction of shrinkage will further reduce the ability to make a strong seal. It cannot be determined in advance. Because of all these disadvantages, this embodiment is less preferred.

  Another embodiment of the present invention is illustrated in FIGS. 20 and 21 generally as a bag 415c. Again, like elements include like reference numerals. The bag 415c includes a first seal 616, which includes a butt seal tape 641 comprising a butt seal film 611 having a first frame 607, a second frame 609, a sealing surface 615, and an outer surface 614. . The first seal 616 includes a first heat seal 618, the first heat seal 618 butt the first side 430 a of the bag wall 430 to the first frame 607 of the sealing tape 641 in the vertical direction, and The second heat seal 619 has the second side 430 b of the bag wall portion 430 abutted against the second frame portion 609 of the sealing tape 641 in the vertical direction. Thus, the first side 430a and the second side 430b are joined in an adjacent cutting edge relationship, thereby forming a bladder wall 430 therebetween without a direct heat seal. Preferably, the butt-seal film 611 comprises the same film as described above for the bags 415, 415a and 415b illustrated in FIGS. 10-19 and the outer heat-sealable layer 438 (FIG. 11) has an inner surface. 615. Thus, the bag 415c can be manufactured from a film that does not contain a peelable system therein, but can be peeled off by means of a peelable system included in the butt seal tape 641 used to form the first seal 616. Includes Conversely, film 411 preferably includes a strippable system but no butt seal tape, or both film 411 and butt seal film 611 may be compatible with the other. It may include a peelable system. The butt seal film 611 is preferably heat shrinkable, but is not required. A pull flap 440 may be provided on the butt seal tape 641 to provide an area for the consumer to grasp and pull to easily open the bag 415. If the butt seal tape 641 is sealed to the inner surface 419 of the film 411, then a portion of the first side 430a or the second side 430b may extend outward beyond the first heat seal 618 or the second heat seal 619. A tension flap may be provided for gripping by the consumer. The second seal 420 is preferably a durable seal created between the inner surface 419 of the first bag wall 430a and the second bag wall 430b.

  Although shown in FIG. 20 as being sealed to the outer surface 433 of the first side 430a and the second side 430b, those skilled in the art will appreciate that the butt seal tape 641 forming the first seal 616 can be applied to the bag 410c. (Not shown) so that the sealing surface 615 is heat sealed to the inner surface 419 of the first side 430a and the second side 430b. In this case, preferably, at least one of the first side 430a and the second side 430b includes a portion extending beyond the heat seal and outward with respect to the butt seal tape 641. Thus, a tension flap is provided for the consumer to grasp.

  A further embodiment of the present invention is illustrated in FIGS. 22 and 23 generally as 415d. Similar elements described above with respect to bags 415, 415a, 415b and 415c are also given the same reference numerals in bag 415d. The bag 415d includes a first seal 716, which comprises a seal strip 741 consisting of a strip film 711 having an inner surface 714 and an outer surface 715. The seal strip 741 includes a first edge 718 that is first sealed by the first heat seal 720 such that the outer surface 715 is heat sealed in face-to-face contact with the inner surface 419 of the film 411. 430a is heat sealed in the vertical direction. The sealing strip 741 includes a second edge 719, which is sealed by the second heat seal 721 such that the inner surface 714 is sealed in face-to-face contact with the outer surface 433 of the second side 430b. It is heat sealed longitudinally to side 430b. A tension flap 440 is provided by including a portion of the strip film 711 that extends outward beyond the second heat seal 721 joining the second edge 719 and the second side 430b. Alternatively, the first side 430a may include a portion that extends outward beyond the second heat seal 420.

  Preferably, the strip film 711 comprises a peelable system and comprises the same film as described above for the bags 415, 415a and 415b and illustrated in FIGS. Layer 438 (FIGS. 12-13) forms inner surface 714. In this embodiment, the heat seal 721 is peelable, and the film 411 needs not to include a peelable system. Alternatively, the outer heat sealable layer may include an outer surface 715 so that the heat seal 720 can be peeled off. In this case, the film 411 needs not to include a peelable system, and the second seal 420 can be made durable. In an embodiment similar to that described for bag 415c, strip film 711 may not include a strippable system and film 411 does not include a strippable system, or both film 411 and strip film 711 may include It may include compatible strippable systems. Strip film 711 is preferably, but not necessarily, heat shrinkable.

  The bag according to the present invention is preferably as described in United States Patent Application No. 10/371950 to Gregory Robert Pocket, et al. It is made continuously from a continuous sheet or web. This web is slit to the desired width and fed to a bag making machine where the longitudinal edges of the film are aligned with each other and either a wrap seal (bags 415 and 415a) or a fin seal (bag 415b). To form a continuous single seam tube or tube member. A transverse seal is made across the tube member, and the portion containing the transverse seal is cut from the continuous tube to form individual bags. Generally, a heat seal is made by applying sufficient heat and pressure between the surfaces of two polymer film layers for a time sufficient to cause fusion between the polymer film layers. As a general method for forming a heat seal, a heating rod sealing method in which adjacent polymer layers are held in face-to-face contact by opposed rods, at least one of which is heated, an adjacent polymer layer Are held in face-to-face contact by opposing rods, one of which includes a wire or ribbon that is energized for a short period of time to generate sufficient heat to cause fusion to the film layer. An impulse sealing method may be used. In general, the performance of the sealing layer of the film becomes even more important as less area is bonded with the impulse seal to the heating rod seal. However, impulse seals are generally more aesthetic because they use less area to form the bond.

  The film selected to make the container of the present invention is preferably biaxially stretched by well-known blown or double bubble techniques, for example, as described in U.S. Patent Nos. 3,456,044 and 6,511,688. Please refer to these if desired. In this technique, the extruded first tube leaving the tube extrusion die is allowed to cool, fold, then stretched, preferably by reheating, inflated again to form a second bubble, and allowed to cool again. The film is preferably biaxially stretched, where transverse (TD) stretching is achieved by inflation to radially expand the heated film. The machine direction (MD) stretching is preferably accomplished by drawing or drawing the film tube in the machine direction using nip rolls rotating at different speeds. The draw ratio of biaxial stretching to form the bag material is preferably sufficient to give the film a total thickness of about 1 to 8 mils. The MD draw ratio is typically 3: 1 to 5: 1, and the TD draw ratio is also typically 3: 1 to 5: 1.

  Referring now to FIG. 24, the double bubble method (also known as the inflate method) is shown. The polymer blends that make up several layers are co-extruded by conveying separate melt streams 611 a, 611 b and 611 c to die 630. These polymer melts are combined and coextruded from an annular die as a relatively thick-walled multilayer tube 632. The thick walled first tube 632 leaving the extrusion die is cooled and collapsed by a nip roller 631, and the collapsed first tube 632 is then transported by transport rollers 633a and 633b to a reheat zone where it is conveyed. The tube 632 is re-heated below the melting point of these layers being stretched and inflated with a confined fluid, preferably a gas, most preferably air, to form a second bubble 634 and cooled. . A second bubble 634 is formed by the fluid trapped between a first pair of nip rollers 636 at one end of the bubble and a second pair of nip rollers 637 at the opposite end of the bubble. Inflation, which causes the film to expand radially, provides stretching and stretching in the transverse direction (TD). Stretching in the machine direction (TD) is achieved by adjusting the relative speed and / or size of the nip rollers 636 and 637 to stretch (stretch) the film in the machine direction.

  Biaxial stretching is preferably 10 mil or less, typically about 1.25 to 8.0 mil, more preferably 5 mil or less, and even more preferably 1.75 to 3.0 mil (44. 5 to 76 μm).

  After stretching, the tubular film 638 is preferably folded to a folding diameter of up to 80 inches, typically about 5 to 30 inches, cut longitudinally, flattened, and used as a web material. Is wound around the reel 639. One of skill in the art can use the methods described above to form films, while providing other conventional methods, including stretching, such as single bubble blown film with subsequent stretching or slot cast sheet extrusion. Will be able to make films by tentering. Further, those skilled in the art will recognize that the flat width of the collapsed tube determines the width of the resulting sheet film. Accordingly, the dimensions of the first tube and subsequent processing can be selected to provide the maximum flat width and film thickness for the desired application, thereby advantageously maximizing the production capacity of the film production equipment. Can be.

  Advantageously, the bag manufacturer provides bags of various lengths and widths from a roll of film take-up material, for that particular bag or series of bags, the width and lateral end seals of the sheets and the bag mouth. It can be manufactured by adjusting the interval between them. This advantageously eliminates the costly need to manufacture seamless tubes of certain widths that are widely used by butchers in recent years and do not include a peelable seal. The invention also enables cost savings and manufacturing efficiencies by allowing bags of many widths and lengths to be manufactured from standard web material. The bag manufacturer simply forms a continuous tube member by slitting the film web to the desired width and longitudinally sealing opposing sides as described for bags 415, 415a and 415b. Good. Adjustable length bags can be made by sealing the tube member laterally and cutting the tube member at a distance from the lateral seal.

  Preferably, the manufacture of the bag is a continuous process illustrated in FIG. 25, in which the film is directed to a bag manufacturing assembly (not shown) where individual end seal bags are made. Film 411 is continuously supplied from reel 639 and is optionally slit to form film 411a of desired width and unused film 411b. The film 411a is supplied to a bag manufacturing assembly device (not shown). The unused film 411b may be wound on a reel 639b for later use or supplied to another bag making assembly. The first side 430a and the second side 430b of the film 411a are mated together and preferably longitudinally sealed with a first seal, e.g., a wrap seal 416 having an additional overlap that acts as a tension flap, and seams to the back. A continuous tubing member 418 is formed. The second seal 420 is provided laterally at a desired location away from the opening 424 over the tube member 418. The tube member 418 is then cut (preferably simultaneously) to separate the portion containing the second seal from the continuous tube, thereby forming a bag 415. Typically, when a transverse seal is made for one bag, a transverse cut is being made that forms the mouth of an adjacent bag. This process is based on the bottom edge formed by the lateral heat seal when flattened, the opening formed by the cut edge, and the folds that occur when the tube member is flattened. A so-called "end seal" pouch is formed having two side edges formed.

  The transverse seal should extend throughout the tube member to ensure a hermetic seal (if such is desired). Each bag being formed from one tube member is necessarily formed by at least two usually parallel, spaced apart transverse cuts which can be segments of the tube member, and these cuts are usually One lateral seal adjacent to one of the sections will define a bag base located opposite the bag opening formed by the remote cut. The distance between this lateral seal and the opening, which can be varied, will determine the length of the bag formed. The length of the bag can be easily changed by changing the spacing between the transverse seal and the cut. The width of the bag can also be easily changed by changing the width of the film by slitting a standard roll.

Unless otherwise noted, the following physical properties are used to describe the films and seals of the present invention. These properties are measured either by the test procedures described below or by test methods analogous to the following methods.
Average gauge: ASTM D-2103
Tensile strength: ASTM D-882, Method A
1% secant modulus: ASTM D-882, Method A
Oxygen gas permeability (O 2 GTR): ASTM D-3985-81
Elongation at break: ASTM D-882, Method A
Molecular weight distribution: gel permeation chromatography Gloss: ASTM D-2457, angle 45 °
Haze: ASTM D-1003-52
Melt index: ASTM D-1238, Condition E (190 ° C.) (excluding propene-based (> 50% C 3 content) polymers tested under Condition L (230 ° C.))
Melting point: ASTM D-3418, peak determined by DSC at a heating rate of 10 ° C./min. p.
Vicat softening point (Vsp): ASTM D-1525-82
Seal strength: ASTM F88-94 (standard test method for seal strength of flexible barrier materials).
All ASTM test methods described herein are incorporated by reference into this disclosure.

Shrinkage value :
Shrinkage values are obtained by measuring the unrestricted shrinkage of a 10 cm 2 sample immersed in water at 90 ° C. (or the indicated temperature if different) for 10 seconds. Four specimens are cut from a given sample of the film to be tested. The test specimen is cut into a square of 10 cm length (MD) × 10 cm length (TD). Each specimen is completely immersed in a water bath at 90C (or the indicated temperature if different) for 5-10 seconds. The test piece is then removed from the water bath and the distance between the ends of the contracted test piece is measured in both the MD and TD directions. The difference between the measured distance of the contracted test piece and each of the original 10 cm sides is multiplied by 10 to obtain the contraction rate in each direction. Average the shrinkage of the four specimens and report the average MD and TD shrinkage values. The term “heat-shrinkable film at 90 ° C.” means a film that has an unlimited shrinkage value of at least 10% in at least one direction.

Five identical samples of tensile seal strength (seal strength) test film are 1 inch (2.54 cm) wide and a length suitable for the test equipment, eg, about 5 inches (12.7 cm) long. And a 1 inch (2.54 cm) wide seal is centered and positioned laterally. The opposing parts of the film sample are secured to opposing clamps of a universal tensile test instrument. The film is secured between the clamps by a taut sliding fit without stretching before the start of the test. The test is performed at ambient or room temperature (RT) (about 23 ° C.) test temperature. The instrument was operated to break the film at a constant rate of 12.0 inches per minute (30.48 cm) through a clamp beside the seal (breakage or delamination of the film or seal and delamination and film breakage). (Loss of integrity). The indicated test temperature and 1 bs. The force at break is measured and recorded. This test is repeated for four additional samples and the average gram at break is reported.

Ram Rupture Test The ram rupture test is used to determine the maximum breaking load or breaking force and the maximum breaking stress of a flexible film when hit with a hemispherical or spherical hammer. This test gives a quantitative measure of the fracture resistance of thin plastic films. This test is further described in US patent application Ser. No. 09 / 401,692. See if desired.

  The following are examples and comparative examples given to illustrate the invention.

  In all of the following examples, unless otherwise noted, film compositions are generally described in U.S. Pat. Nos. 3,456,044 (Pahlke) and 6,511,688 (Edwards et al.) Which describe coextrusion blown processes. Manufactured using the apparatus and method described above and further according to the detailed description above. In the following example, all layers are extruded (co-extruded in the multilayer example) as a first tube, which is cooled as soon as it exits the die, for example by injection with tap water. The first tube is then reheated, stretched, and cooled as taught in the above patent.

Example 2
A heat-shrinkable bag according to the present invention as generally exemplified in FIGS. 10 and 11 is applied from the inner surface to the outer surface by (A) an internal heat-sealable layer, (B) a barrier layer, (C) a core layer, and (D). It is manufactured from a film consisting of a coextruded 5-layer biaxially stretched shrinkable film having a tie layer and (E) an outer heat-sealable layer. The inner and outer layers are directly bonded to opposing faces of the barrier layer. The five layers contained the following composition:
(A) 37% by weight of VLDPE, 24% of EVA, 33% of plastomer (EXACT4053), 6% of processing aids (B) About 85% of vinylidene chloride-vinyl chloride copolymer and about 15% of vinylidene chloride・ Blend of methacrylic acid ester copolymer (C) 100% by weight of EMA
(D) 20% by weight VLDPE, 33% plastomer (EXACT4053) and 20% by weight polybutylene, and (E) 40% by weight VLDPE, 33% plastomer (EXACT4053), 25% EVA, 2% processing Auxiliaries.

  One extruder was used for each layer. Each extruder was connected to an annular co-extrusion die where the thermoplastic resin was co-extruded to form a first tube. The resin mixture for each layer was fed from a hopper to an attached single screw extruder, where the mixture was thermoplasticized under conditions similar to those disclosed in co-pending US patent application Ser. No. 10 / 371,950. And extruded from a five-layer coextrusion die into a first tube.

  Although not essential, it is preferred to irradiate the entire film with radiation to extend the range of heat sealing and / or to improve the toughness of the inner and outer layers by radiation-induced crosslinking and / or cutting. This is preferably done by irradiation with an electron beam at a dose level in the range of at least about 2 megarads (MR), preferably 3-5 MR, but higher doses, specifically for thicker films or It may be used when irradiating one tube. Irradiation can be performed on the first tube or after biaxial stretching. The latter, called post-irradiation, is preferred and is described in Lustig et al., US Pat. No. 4,737,391. See if desired. The advantage of post-irradiation is that a relatively thin film is processed instead of a relatively thick first tube, thereby reducing the power required for a given processing level.

  The film is wound and slit to the desired width. The film is then fed to a bag making machine to form a tube member having a continuous wrap seal extending in the longitudinal direction. A bag according to bag 415a shown in FIG. 14 can be formed by sealing laterally across the tube member and simultaneously separating the sealed portion from the continuous tube structure.

  Various tests can be performed on the bag of the present invention obtained. The gauge thickness will typically be 10 mils or less, preferably 1.25 to 5.0 mils film thickness. The wrap seal should typically have an average seal strength of at least 2 Kg / inch. The end seal will typically have an average seal strength of at least 3 Kg. The bag will also have an average MD and TD heat shrinkage at 90 ° C. of at least 20%, preferably at least 40%, respectively, in both directions. This preferred bag has very good heat shrinkage, which is very desirable for packaging raw red meat fillets, and also has very good puncture resistance, and more advantageously, It incorporates a peelable seal that was not found on food packaging bags. Therefore, it is economical to manufacture, has a peelable seal, puncture resistance and a strong end seal, and is heat shrinkable with a unique combination of previously unknown features and commercial advantages A bag is provided.

  The present invention advantageously provides individual heat-shrinkable bags having easily peelable seals. Thus, the container or bag of the present invention can be easily opened without resorting to knives or other cutting / opening devices, which makes it possible for food manufacturers to provide desirable consumer-oriented packages. Make it possible.

  Another preferred embodiment of the present invention uses seven layers of heat shrinkable film to produce a back seamed material. This seven-layer film has several advantages over three and five layers. When a polymer having a high melt index of 2.0 dg / 10 min or more, for example, an ethylene α-olefin copolymer such as EXACT4053, is used for the sealant layer, the seal is assisted by folds and wrinkles in the seal. This is important. This is because the overlapping areas create wrinkles in the seal.

Another advantage is a strong cohesive polymer such as Emact SP1330, which has a density of 0.948 g / cm 3 , a melt index of 2.0 g / 10 min, a melting point of 93 ° C., a softening point of 49 ° C. and (Reported to have a 22% methyl acrylate (MA) content) as a PVDC tie layer to provide improved adhesion. . This has been shown to give excellent adhesion. EMA gives the finished film an adhesion of more than 100 g. A preferred seven-layer structure includes a first heat seal layer composed of an ethylene α-olefin copolymer (EXACT3139 manufactured by Exxon), EVA (Exxon701.ID), an ethylene / 1-butene copolymer (EXACT4053 manufactured by Exxon), A second strippable tie layer made of a polymer blend having 15 to 35% of an ethylene / 1-octene copolymer (VLDPE10B manufactured by Nova), and a third tie layer made of, for example, EMA (Voridian SP1330) And a fourth barrier layer, for example, as described in Example 1, a fifth tie layer, for example made of EMA, and EVA, ethylene / 1-butene copolymer and ethylene / 1-octene copolymer each of 20 to A sixth intermediate layer composed of a blend having 45% and an ethylene / α-olefin copolymer such as EX manufactured by Exxon And a seventh outer surface layer made of CT3139.

  The film is preferably 2 mils overall, with the ratio of layer thicknesses for the first to seventh layers being 10: 42: 5: 18: 5: 15: 5, respectively.

  The bags 415, 415a, 415b, 415c and 415d can be economically manufactured from almost any size. This is because these bags are not formed from seamless tubes that must be made to the desired width. The only limitation on the size of the bag made is the size of the webbing film. Standard webbing films are available in widths of over 100 inches. The present invention allows a bag manufacturer to produce bags of any size from flat sheets of the same winding material to the size limits of this winding material. For example, if the roll is 52 inches wide, it will have a fold diameter of approximately 26 inches, taking into account the amount of overlap, gap or contact between the first seals 416, 516, 616 and 716 used. Tube members can be manufactured. For example, if a manufacturer wants to produce a wrap seal or fin seal pouch having a 18 inch folding diameter, then the manufacturer may need to standard wrap the appropriate width (in the area of the first seal 416 or 516). To about 36 inches). The unused portion slit from the standard roll is re-rolled for use in producing bags of different dimensions. In this embodiment, a standard webbing film can be produced more economically. This is because film production equipment can operate at or near the upper limit of film width production, thereby using almost all of the capacity of the equipment. Making bags from seamless tubes requires that the film production equipment be operated with limited capacity to form tubes of different small widths. In addition, the film production equipment requires costly equipment and breaks between operations of different sizes which significantly increase the cost of producing seamless tubes.

  Although an end seal bag having a seamless side with a heat-shrinkable film that can be easily peeled has been described above, in consideration of this disclosure, a side seal heat-shrinkable bag and a pouch made of a plurality of films are also provided by the present invention. It will be apparent that a heat-shrinkable container can be provided that is easy to peel and open, which is compatible with. The present invention can be used in a heat-shrinkable state formed in a pouch as described in U.S. Patent Nos. 6,015,235 (Kraimer et al.) And 6,206,569 (Kraimer et al.). Please refer to these if desired.

  Although the invention has been described with respect to particular embodiments, those skilled in the art will recognize that many modifications may be made without departing from the scope and spirit of the invention, and that such modifications Will be recognized as being within the range.

FIG. 2 is a schematic view illustrating an end-sealed shrink sack having a wrap seal according to the present invention in a slightly open state from a lay-flat state. 2 is a cross-sectional view of the bag illustrated in FIG. 1 taken along line 2-2 of FIG. 1. FIG. 3 is a schematic view illustrating a terminal seal shrink bag having a fin seal according to the present invention in a slightly opened state from a lay flat state. FIG. 4 is a cross-sectional view of the bag illustrated in FIG. 3 taken along line 4-4 of FIG. 1 is a schematic view of an end seal shrink bag having a butt seal according to the present invention with the end seal shrink bag slightly opened from a lay flat state. 6 is a cross-sectional view of the bag illustrated in FIG. 5 taken along line 6-6 of FIG. FIG. 3 illustrates a preferred three-layer film structure for forming a bag according to the present invention. 1 is a schematic diagram of a preferred method of making a film for use in the present invention. FIG. 3 illustrates a preferred seven-layer film structure for forming a bag according to the present invention. 1 is a schematic view of a peelable sealed heat shrink sack according to the present invention. 1 is a schematic diagram illustrating a preferred embodiment of a heat-shrinkable bag according to the present invention in a substantially lay-flat state. The line AA of FIG. 11 shows, on an enlarged scale (not to scale), a preferred wrap seal portion of the film for use in making the bags illustrated in FIGS. It is the fragmentary sectional view obtained by cutting along. FIG. 12 is a partial cross-sectional view taken along line BB of FIG. 11 showing an enlarged (not to scale) of the end seal portion of the preferred film. FIG. 4 is a schematic view of another preferred embodiment of a heat shrinkable bag according to the present invention having a tension flap. FIG. 15 is a cross-sectional view of the bag illustrated in FIG. 14 taken along line CC of FIG. 14. FIG. 16 is a cross-sectional view taken along line DD of FIG. 15 showing the end seal. FIG. 11 illustrates yet another bag according to the invention having a fin seal back seam. FIG. 18 is a cross-sectional view of the bag illustrated in FIG. 17 obtained by cutting along a line EE. FIG. 19 is a partially enlarged cross-sectional view of the seal of FIG. 18 showing a preferred film structure in detail. FIG. 7 illustrates another embodiment of a bag according to the present invention having a back seam of a butt seal. FIG. 21 is a cross-sectional view of the bag illustrated in FIG. 20 obtained by cutting along a line FF. Fig. 4 illustrates another bag according to the invention having a release strip. FIG. 23 is a cross-sectional view of the bag illustrated in FIG. 22 obtained by cutting along the line GG. 1 is a schematic diagram of a preferred method of making a film for use in the present invention. 1 is a schematic diagram of a preferred method of manufacturing a bag according to the present invention.

Explanation of reference numerals

Reference Signs List 10 bag 11 heat-shrinkable film 12 first edge 13 top surface 14 second edge 15 bottom surface 16 first seal 18 tube member 20 first bag wall 20
22 second bag wall 28 opening 30 bag end 32 second seal 34 product storage chamber 42 blocking layer 44 internal heat sealing layer 46 external layer 60 film 61 internal layer 67 external layer 110 bag 116 first seal 117 fin 118 Tube member 132 Second seal 210 Bag 213 Internal surface 215 External surface 216 First seal 232 Second seal 311a Melt flow 311b Melt flow 311c Melt flow 330 Die 331 Nip roller 332 First tube 333a Transport roller 333b Transport roller 338 Stretched film 339 Reel 411 Heat shrinkable film 412a First edge 412b Second edge 413c Third edge 413d Fourth edge 416 Wrap seal 418 Tube member 419 Inner surface 420 Second seal 421 Sealed Edge 422 First bag edge 423 Second bag edge 424 Bag mouth 425 Product storage room 433 External surface 434 Heat sealing layer 435 Blocking layer 436 Core layer 437 Tie layer 438 Heat sealing layer 440 Tensile flap 516 First Fin seal 607 First frame 609 Second frame 611 Seal film 615 Seal surface 616 First seal 618 First heat seal 619 Second heat seal 641 Butt seal tape 711 Strip film 714 Inner surface 715 Outer surface 716 First seal 718 First edge 719 Second edge 720 First heat seal 741 Seal strip


Claims (105)

  1. An individual end-sealed packaging container formed from a sheet of heat-shrinkable film having a first edge and a second edge opposite thereto,
    Joining the first edge and the second edge, whereby a first tube wall, a second tube wall, opposing first and second lay flat edges, a distal end and an opening; A first seal defining a tube member having a first lay flat edge and a second lay flat edge;
    A second seal provided through the first tube wall and the second tube wall, wherein the second seal extends laterally at a position near the distal end over the width of both the first wall and the second wall. An individual end-sealed package, characterized in that the empty product receiving chamber comprises the first wall, the second wall, the second seal and the opening defined by the opening. Container.
  2. The container of claim 1, wherein the first seal comprises a fin seal, a wrap seal, or a butt seal.
  3. 3. The container of claim 1 or 2, wherein the film has a thickness from about 1.5 mil to about 4.0 mil.
  4. The container according to any one of claims 1 to 3, wherein the film comprises a biaxially stretched film having a shrinkage value of at least 30% at 90 ° C in at least one direction.
  5. 5. The container according to claim 4, wherein the shrinkage value is in a machine direction.
  6. The container according to claim 4 or 5, wherein the biaxially stretched film comprises a multilayer film having an inner layer, a core layer, and an outer layer.
  7. The core layer is selected from the group consisting of vinylidene chloride copolymer, vinylidene chloride / vinyl chloride copolymer, vinylidene chloride / methyl acrylate copolymer, ethylene / vinyl alcohol copolymer, polyamide, and a blend of two or more thereof. The container according to claim 6, comprising a polymer to be prepared.
  8. The container according to any one of claims 1 to 7, wherein the film comprises a seven-layer film.
  9. The container according to claim 8, wherein the seven-layer film has a structure of inner layer / second layer / first tie layer / blocking layer / second tie layer / third layer / outer layer.
  10. The barrier layer is selected from the group consisting of vinylidene chloride copolymer, vinylidene chloride / vinyl chloride copolymer, vinylidene chloride / methyl acrylate copolymer, ethylene / vinyl alcohol copolymer, polyamide, and a blend of two or more of them. 10. The container according to claim 9, comprising a polymer to be prepared.
  11. The container according to claim 9 or 10, wherein the first tie layer is made of an ethylene / methyl acrylate copolymer.
  12. The container according to claim 9, wherein the second tie layer is made of an ethylene / methyl acrylate copolymer.
  13. 13. The container according to any of claims 9 to 12, wherein the inner layer comprises a polyolefin having a melt index of at least 7.0 g / 10 minutes.
  14. The container according to any of claims 9 to 13, wherein the outer layer comprises a polyolefin having a melt index of at least 16.0 g / 10 minutes.
  15. The container according to any of the preceding claims, wherein the container has a print thereon.
  16. The container according to claim 15, wherein the container is printed with a print.
  17. An end-sealed packaging container formed from a sheet of heat shrinkable film having a first edge and a second edge opposite the edge,
    The first edge and the second edge are joined and a first tube wall, a second tube wall, opposed first and second lay flat edges, a sealed end and an opening. A first seal defining a tube member having a wrap seal;
    A second seal provided through the first wall and the second wall, wherein the second seal extends laterally at a location near the distal end over the width of both the first wall and the second wall; Wherein the product storage chamber comprises a first wall, a second wall, a second seal and an opening defined by the opening.
  18. An end-sealed packaging container formed from a sheet of heat shrinkable film having a first edge and a second edge opposite the edge,
    The first edge and the second edge are joined and a first tube wall, a second tube wall, opposed first and second lay flat edges, a sealed end and an opening. A first seal defining a tube member having a butt seal;
    A second seal provided through the first wall and the second wall, the seal extending laterally at a location near the distal end over the width of both the first wall and the second wall; An end-sealed packaging container, characterized in that the product compartment comprises by this first wall, the second wall, the second seal and the opening.
  19. Next steps:
    (1) preparing a heat-shrinkable thermoplastic film having a first edge and a second edge opposite to the first edge;
    (2) aligning the first edge and the second edge with each other;
    (3) forming a first seal for bringing the first edge portion and the second edge portion into close contact to form a tube member having a first tube wall portion, a second tube wall portion, a bottom portion, and an opening; Let
    (4) Individual end seals from a flat sheet of film, including providing the first tube wall and the second tube wall with a second seal extending laterally across the tube member at a location near the bottom. A method for forming a heat-shrinkable packaging container.
  20. 20. The method of claim 19, wherein the heat-shrinkable thermoplastic film comprises a print.
  21. The method according to claim 19 or 20, wherein the first seal comprises a lap seal, a butt seal or a fin seal.
  22. 22. The method according to any of claims 19 to 21, wherein the flat sheet of film is slit to a desired width before the first and second edges are brought together.
  23. The method according to any of claims 19 to 22, wherein the heat-shrinkable thermoplastic film has a shrinkage value of at least 30% in at least one direction at 90C.
  24. Further comprising the step of providing the tube member with a cut transversely extending transversely at least over the width of at least both the first tube wall and the second tube wall to separate the container from the continuous roll of flat sheet film. Item 24. The method according to any one of Items 19 to 23.
  25. 25. The method of claim 24, wherein the cut is provided prior to providing the second seal.
  26. A first film tube is co-extruded with a heat-shrinkable thermoplastic film, the first film tube is allowed to cool, the first film tube is folded, the first tube is blown, and the blown first film is blown. Reheating the tube, biaxially stretching the first film tube, allowing the first film tube to cool, refolding the first film tube, and slitting the first film tube to make a film sheet The method according to any of claims 19 to 25, wherein the method is formed by:
  27. The method according to any of claims 19 to 26, wherein the first seal is linear.
  28. The method according to any of claims 19 to 27, wherein the second seal and the cut are curved.
  29. The method according to any of claims 19 to 28, wherein the first seal has a seal strength of at least 8000 g.
  30. Next steps:
    (1) coextruding the first film tube,
    (2) The film tube is biaxially stretched to give a tube stock of a heat-shrinkable film,
    (3) slitting the tube stock to form a continuous sheet of film;
    (4) The continuous flat sheet of the film is slit in the longitudinal direction to form a bag-like film having a desired width, wherein the bag-like film having the desired width has a first edge portion and a second edge portion opposite to the first edge portion. Has an edge,
    (5) sealing the first and second edges to form a first wall, a second wall, and a product storage chamber defined between the first and second walls; Forming a tube member having
    (6) providing the first wall and the second wall with a first lateral seal extending laterally across the width of the tube member;
    (7) The tube member is provided with a cut portion extending laterally across the width of the tube member, and thereby has a bag mouth at one end formed by the cut portion, and A method of forming a heat shrinkable bag, comprising forming a bag with the first lateral seal near a bag end at an opposite end.
  31. 31. The method of claim 30, wherein a continuous sheet of film is wrapped around a roll before slitting to form a bag of desired width.
  32. A tubular film for the manufacture of an end-sealed packaging container formed from a sheet of heat-shrinkable film having a first edge and a second edge opposite thereto,
    The first edge and the second edge are vertically adhered, and have a first tube wall, a second tube wall, and opposing first and second lay flat edges, and A distal seal defining a tube member having a fold diameter of 22 inches (55.88 cm) or greater, the seal comprising a member selected from the group consisting of a wrap seal, a butt seal, and a fin seal. Tubular film for the production of sealed packaging containers.
  33. A tubular film for the manufacture of an end-sealed packaging container formed from a sheet of heat-shrinkable film having a first edge and a second edge opposite thereto,
    The first edge and the second edge are vertically adhered, and have a first tube wall, a second tube wall, and opposing first and second lay flat edges, and Manufacture of a terminal sealed packaging container comprising a first seal defining a tube member including a print thereon, the first seal selected from the group consisting of a wrap seal, a butt seal and a fin seal. Tube-like film.
  34. 34. The tubular film of claim 33, wherein the print indicates that a product containing bone is contained therein.
  35. A tubular film for the manufacture of an end-sealed packaging container formed from a sheet of heat-shrinkable film having a first edge and a second edge opposite thereto,
    A first tube wall, a second tube wall, and opposing first and second lay flat edges and a second lay flat edge; Moreover, a first seal having a folding diameter of 22 inches (55.88 cm) or more and defining a tube member including a print thereon, which is selected from the group consisting of a wrap seal, a butt seal, and a fin seal. A tubular film for the production of end-sealed packaging containers, characterized in that it comprises:
  36. The tubular film of any of claims 32-35, wherein the film has a thickness from about 1.5 mils to about 4.0 mils.
  37. 37. The tubular film according to any of claims 32-36, wherein the film comprises a biaxially stretched film having a shrinkage value of at least 20% at 90 ° C in at least one direction.
  38. An individual end-sealed packaging bag formed from a sheet of heat-shrinkable film having a first side, an opposite second side, an inner surface and an outer surface, the bag comprising the first side. To the second side, and a first bag wall, a second bag wall, opposing first and second bag edges, a distal end, and an opening opposite the distal end. A first seal defining a tube member having:
    A second seal provided through the first bag wall and the second bag wall, wherein the second seal is laterally located at a position close to the end portion over both widths of the first bag wall and the second bag wall. , Whereby the empty product receiving chamber includes the first bag wall, the second bag wall, the second seal and the opening defined by the opening, and wherein the first seal and the second An individual end-sealed packaging bag, wherein at least one of the seals comprises a peelable seal.
  39. 39. The bag of claim 38, wherein the first seal is selected from the group consisting of a wrap seal, a fin seal, a butt seal, and a seal strip, and wherein the first seal comprises a peelable seal.
  40. The first seal is a butt seal tape having a first frame portion and a second frame portion, a first heat seal for bringing the first frame portion into close contact with the first side portion, and the second frame portion is formed by the second heat seal. 40. A bag according to claim 38 or 39, comprising a butt seal including a second heat seal in intimate contact with the side.
  41. 41. The bag of claim 40, wherein the butt seal includes a tension flap.
  42. 42. The bag of claim 40 or 41, wherein a first frame portion is heat sealed to an inner surface of the first side, and a second frame portion is heat sealed to an inner surface of the second side.
  43. 43. The bag of claim 40, 41 or 42, wherein at least one of the first side and the second side extends outward to form a tension flap.
  44. The bag according to any one of claims 40 to 43, wherein the butt seal tape comprises a butt seal film including a peelable system.
  45. The bag according to any one of claims 38 to 44, wherein the first heat seal and the second heat seal are peelable.
  46. A bag according to any of claims 38 to 45, wherein the sheet of heat shrinkable film comprises a peelable system.
  47. A first seal formed of a strip film having a first edge, a second edge, an inner surface, and an outer surface, and the outer surface of the first edge being in close contact with the inner surface of the first side; 47. The bag of any one of claims 38 to 46, comprising: a first heat seal to be made; and a second heat seal to make the inner surface of the strip film adhere to the outer surface of the second side.
  48. 48. The bag of claim 47, wherein the second heat seal is a peelable seal.
  49. 49. The bag according to claim 47 or 48, wherein the first heat seal is a peelable seal.
  50. 50. A bag according to any of claims 47 to 49, wherein the strip film comprises a peelable system.
  51. A bag according to any of claims 47 to 50, wherein the strip film comprises a tension flap.
  52. A bag according to any of claims 40 to 51, wherein the sheet of heat shrinkable film comprises a peelable system.
  53. A bag according to any of claims 40 to 52, wherein the film comprises a multilayer barrier film.
  54. Multi-layer barrier film
    (A) an inner heat sealable layer,
    (B) a blocking layer,
    (C) a core layer,
    54. The bag of claim 53, comprising: (d) a tie layer; and (e) an outer heat sealable layer.
  55. 55. The bag of claim 54, wherein the outer heat sealable layer forms an outer surface of the bag.
  56. 56. The bag of claim 54 or 55, wherein the tie layer is permanently bonded to the core layer and releasably bonded to the outer heat sealable layer.
  57. 56. The bag of claim 54 or 55, wherein the tie layer is permanently bonded to the outer heat sealable layer and releasably bonded to the core layer.
  58. 58. The bag of any of claims 54 to 57, wherein the tie layer comprises a blend of polybutylene and at least one other component.
  59. 59. The bag of claim 58, wherein at least one other component comprises polyethylene.
  60. The bag according to any one of claims 54 to 59, wherein the outer heat-sealable layer is made of polyethylene.
  61. The bag according to any one of claims 54 to 60, wherein the core layer comprises a blend of polyethylene and an ethylene / vinyl acetate copolymer.
  62. 63. The bag according to any of claims 54 to 61, wherein the barrier layer is selected from the group consisting of vinylidene chloride copolymer, ethylene vinyl alcohol copolymer, polyacrylonitrile and polyamide.
  63. 63. The bag of claim 62, wherein the barrier layer comprises a vinylidene chloride copolymer.
  64. The bag according to any one of claims 54 to 63, wherein the inner heat-sealable layer comprises a blend of polyethylene and an ethylene / vinyl acetate copolymer.
  65. The tie layer comprises a blend of polybutylene and at least one other component, the outer heat-sealable layer comprises polyethylene, the core layer comprises a blend of polyethylene and ethylene-vinyl acetate copolymer, and the barrier layer comprises a chloride. 65. The bag of any of claims 54 to 64, wherein the bag comprises a vinylidene copolymer and the inner heat sealable layer comprises a blend of polyethylene and an ethylene-vinyl acetate copolymer.
  66. 66. The method of claim 65, wherein at least one other component comprises polyethylene and the barrier layer comprises a blend of vinylidene chloride-methyl acrylate copolymer and vinylidene chloride-vinyl chloride copolymer. Bag.
  67. Based on the total thickness of the film, the inner heat sealable layer occupies about 0 to about 50%, the barrier layer occupies about 0 to about 20%, and the core layer occupies about 0 to about 28%. 67. The bag of any of claims 54-66, wherein the tie layer comprises about 0 to about 15% and the outer heat sealable layer comprises about 0 to about 15%.
  68. 68. The bag of any of claims 38-67, wherein the first seal is peelable and has a seal strength of 2 kilograms or less for a 1 inch (2.54 cm) strip.
  69. 69. A bag according to any of claims 38 to 68, wherein the first seal is peelable and has a seal strength of 1.5 kilograms or less per 1 inch (2.54 cm) strip.
  70. 70. The bag of any of claims 38-69, wherein the second seal is peelable and has a seal strength of about 500 to about 1000 grams per 1 inch (2.54 cm) strip.
  71. 71. The bag according to any one of claims 38 to 70, wherein the second seal cannot be peeled off.
  72. 72. The bag of any one of claims 38 to 71, wherein the sheet of heat shrinkable film has a thickness of about 1.25 mil to about 8.0 mil.
  73. 73. The bag of any of claims 38 to 72, wherein the sheet of heat shrinkable film has a thickness of about 1.75 mils to about 3.0 mils.
  74. 74. The bag of any one of claims 38 to 73, wherein the sheet of heat shrinkable film comprises a biaxially stretched film having a shrinkage value of at least 20% shrink in at least one direction at 90C.
  75. 75. The bag of claim 74, wherein the shrinkage value is in the machine direction.
  76. 75. The bag of claim 74, wherein the shrinkage value is transverse.
  77. 75. The bag of claim 74, wherein the shrinkage values are both longitudinal and transverse.
  78. 78. The bag of any of claims 54 to 77, wherein the first seal comprises a wrap seal, and wherein the inner heat sealable layer forms an inner surface of the bag.
  79. 79. The bag of any one of claims 38 to 78, wherein the first seal comprises a wrap seal and the first side includes an unsealed portion extending outwardly beyond the first seal.
  80. An end-sealed packaging bag formed from a sheet of heat-shrinkable film having a first side and a second side opposite thereto,
    The first side and the second side are joined along their entire length, whereby a first bag wall, a second bag wall, opposing first and second bag edges, a distal end. And a first seal defining a tube member having an opening, the first seal comprising a wrap seal and capable of being peeled off;
    A second seal provided through the first wall and the second wall and extending laterally at a position near the distal end over the width of both the first wall and the second wall;
    An end-sealed packaging bag comprising the first wall, the second wall, the second seal, and a product storage chamber defined by the opening.
  81. Next steps:
    (1) preparing a sheet of a heat-shrinkable thermoplastic film having a first side and a second side opposite to the first side;
    (2) A first seal is provided between the first side and the second side to form a tube member having a first bag wall, a second bag wall, a bottom, and an opening. ,
    (3) providing a first seal wall and a second seal wall with a second seal extending laterally across the tube member at a position near the bottom, wherein the first seal and the second seal are acceptable. A method of forming an end-sealed heat-shrinkable packaging bag having at least one peelable seal from a flat sheet of film, comprising a peelable seal.
  82. 82. The method of claim 81, wherein the sheet of heat shrinkable thermoplastic film is slit to a desired width before the first and second sides are brought together.
  83. 83. The method of claim 81 or 82, wherein the sheet of heat shrinkable thermoplastic film has a shrinkage value in at least one direction at 90C of at least 20%.
  84. The sheet of heat-shrinkable thermoplastic film comprises a continuous roll of film sheet, and (f) the tube member is provided with cuts extending laterally over at least the width of both the first and second bag walls. 84. The method of any of claims 81-83, further comprising applying a lateral direction, thereby separating a portion of the tube member including a second seal from the tube member.
  85. A heat-shrinkable thermoplastic film is co-extruded with a first film tube, allowing the first film tube to cool, folding the first film tube, inflating the first film tube, and blowing the inflated first film tube. Reheating the film tube, biaxially stretching the first film tube, allowing the first film tube to cool and re-folding, slitting the first film tube longitudinally, and slitting the first tube 85. The method according to any of claims 81-84, wherein forming is performed by opening a flat sheet of biaxially stretched film.
  86. Next steps:
    (1) coextruding the first film tube,
    (2) The film tube is biaxially stretched to give a tube stock of a heat-shrinkable film,
    (3) slitting the tube stock to form a continuous flat sheet of film;
    (4) slitting the continuous flat sheet of the film in the longitudinal direction to form a bag-like film having a desired width having a first side and a second side opposite to the first side;
    (5) A first seal is provided between the second side portion and the second side portion to provide a first bag wall portion, a second bag wall portion, and a portion between the first bag wall portion and the second bag wall portion. Forming a tube member having a product storage chamber defined therein, wherein the first seal comprises a peelable seal;
    (6) providing between the first bag wall portion and the second bag wall portion a second seal that extends laterally across the width of the tube member and is a durable seal;
    (7) providing a heat-shrinkable bag that includes providing the tube member with a cut extending laterally across the width of the tube member and separating a portion of the tube member from the tube member that includes the lateral seal. Method of forming.
  87. An end-sealed packaging bag formed from a sheet of heat-shrinkable film having a first side, a second side opposite, an inner surface and an outer surface,
    The first side and the second side are adhered along their entire length, and a first bag wall, a second bag wall, opposed first and second bag edges, a distal end and A first seal defining a tube member having an opening, the first seal comprising a wrap seal and being releasable;
    A second seal provided through the first bag wall and the second bag wall and extending laterally at a position near the distal end over the width of both the first bag wall and the second bag wall; ,
    An end-sealed packaging bag comprising the first wall, the second wall, the second seal and a product compartment defined by the opening.
  88. 90. The bag of claim 87, wherein the film comprises a multilayer barrier film.
  89. The film
    (A) an inner heat sealable layer,
    (B) a barrier layer adjacent to the inner heat-sealable layer;
    (C) a core layer adjacent to the barrier layer;
    89. The bag of claim 87 or 88, comprising a multilayer barrier film comprising: (d) a tie layer adjacent to the core layer; and (e) an outer heat sealable layer adjacent to the tie layer.
  90. 90. The bag of claim 89, wherein the tie layer comprises a blend of polybutylene and at least one other ingredient.
  91. 90. The bag of claim 90, wherein at least one other component comprises polyethylene.
  92. The bag according to any one of claims 89 to 91, wherein the outer heat-sealable layer is made of polyethylene.
  93. The bag according to any of claims 89 to 92, wherein the core layer comprises a blend of polyethylene and an ethylene / vinyl acetate copolymer.
  94. The bag according to any of claims 89 to 93, wherein the barrier layer is selected from the group consisting of vinylidene chloride copolymer, ethylene vinyl alcohol copolymer, polyacrylonitrile and polyamide.
  95. The bag according to any one of claims 89 to 94, wherein the barrier layer comprises a vinylidene chloride copolymer.
  96. The bag according to any one of claims 89 to 95, wherein the inner heat-sealable layer comprises a blend of polyethylene and an ethylene / vinyl acetate copolymer.
  97. The tie layer comprises a blend of polybutylene and at least one other component, the outer heat-sealable layer comprises polyethylene, the core layer comprises a blend of polyethylene and ethylene-vinyl acetate copolymer, and the barrier layer comprises a chloride. 97. The bag of any of claims 89 to 96, wherein the bag comprises a vinylidene copolymer and the inner heat sealable layer comprises a blend of polyethylene and an ethylene-vinyl acetate copolymer.
  98. 100. The bag of claim 97, wherein at least one other component comprises polyethylene and the barrier layer comprises a blend of vinylidene chloride-methyl acrylate copolymer and vinylidene chloride-vinyl chloride copolymer.
  99. Based on the total thickness of the film, the inner heat sealable layer occupies about 0 to about 50%, the barrier layer occupies about 0 to about 20%, and the core layer occupies about 0 to about 28%. 99. The bag of any of claims 89-98, wherein the tie layer comprises about 0 to about 15% and the outer heat sealable layer comprises about 0 to about 15%.
  100. 100. The bag of any of claims 87 to 99, wherein the first seal has a seal strength of 3 kilograms per inch (2.54 cm) or more.
  101. The bag of any of claims 87 to 100, wherein the first seal has a seal strength of 6 kilograms per inch (2.54 cm) or greater.
  102. The bag of any of claims 87 to 101, wherein the second seal has a seal strength of 3 kilograms per inch (2.54 cm) or more.
  103. 103. A bag according to any of claims 89 to 102, wherein an outer heat sealable layer forms the outer surface of the bag.
  104. The bag of any of claims 89 to 103, wherein the tie layer is permanently bonded to the core layer and releasably bonded to the outer heat sealable layer.
  105. 105. The bag of any of claims 89 to 104, wherein the tie layer is permanently bonded to the outer heat sealable layer and releasably bonded to the core layer.
JP2004044321A 2003-02-20 2004-02-20 Heat shrinkable packaging Expired - Fee Related JP4750367B2 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US10/371,950 US20040166261A1 (en) 2003-02-20 2003-02-20 Heat-shrinkable packaging receptacle
US10/371950 2003-02-20
US10/645186 2003-08-21
US10/645,186 US7527839B2 (en) 2003-02-20 2003-08-21 Easy open heat-shrinkable packaging

Publications (3)

Publication Number Publication Date
JP2004269053A true JP2004269053A (en) 2004-09-30
JP2004269053A5 JP2004269053A5 (en) 2004-09-30
JP4750367B2 JP4750367B2 (en) 2011-08-17

Family

ID=32737997

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2004044321A Expired - Fee Related JP4750367B2 (en) 2003-02-20 2004-02-20 Heat shrinkable packaging

Country Status (9)

Country Link
EP (1) EP1449787B2 (en)
JP (1) JP4750367B2 (en)
AU (1) AU2004200759B2 (en)
BR (1) BRPI0402590A (en)
CA (1) CA2458136C (en)
IL (1) IL160470A (en)
NO (1) NO20040765L (en)
NZ (1) NZ531295A (en)
PL (1) PL365437A1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006038700A1 (en) * 2004-10-04 2006-04-13 Kyoraku Co., Ltd. Filling-packaging body
US7279206B2 (en) * 2005-03-22 2007-10-09 Curwood, Inc. Packaging laminates and articles made therefrom
JP2008280089A (en) 2007-05-01 2008-11-20 Kraft Foods Holdings Inc Ingredient package and method
JP2012245990A (en) * 2011-05-26 2012-12-13 Kyoraku Co Ltd Packaging bag

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102014008957A1 (en) * 2014-06-23 2015-12-24 Tesseraux Spezialverpackungen Gmbh Round bottom bag, method for producing a round bottom packaging and hotmelt adhesive package

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01124558A (en) * 1987-10-30 1989-05-17 Idemitsu Petrochem Co Ltd Multi-layer bag
US4944409A (en) * 1988-02-10 1990-07-31 Curwood, Inc. Easy open package
EP0435498A2 (en) * 1989-12-08 1991-07-03 W.R. Grace &amp; Co.-Conn. High shrink energy/high modulus thermoplastic multi-layer packaging film and bags made therefrom
US5888648A (en) * 1996-09-12 1999-03-30 Mobil Oil Corporation Multi-layer hermetically sealable film and method of making same
JP2000142724A (en) * 1998-11-09 2000-05-23 Toppan Printing Co Ltd Easily unsealable bag-shaped packaging body
US6221410B1 (en) * 1992-09-25 2001-04-24 Cryovac, Inc. Backseamed casing and packaged product incorporating same
JP2002146343A (en) * 2000-08-22 2002-05-22 Mitsui Chemicals Inc Sealant resin composition, sealant film and its use

Family Cites Families (34)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1154760B (en) * 1959-03-04 1963-09-19 Albert A Vail od packaging for food and food products. like.
US3456044A (en) 1965-03-12 1969-07-15 Heinz Erich Pahlke Biaxial orientation
US3655503A (en) 1969-01-13 1972-04-11 Crown Zellerbach Corp Package of composite film with peelable, heatsealable surfaces
US4058632A (en) 1974-12-16 1977-11-15 Koninklijke Emballage Industrie Van Leer B.V. Light-weight, flexible, easy-open, impermeable package system
US4252846A (en) 1975-09-22 1981-02-24 The Dow Chemical Company Packages embodying a controlled peel seal and method of preparing same
US4189519A (en) 1978-08-30 1980-02-19 American Can Company Heat sealable resin blends
US4550141A (en) 1983-08-22 1985-10-29 E. I. Du Pont De Nemours And Company Blends of ionomer with propylene copolymer
US4615926A (en) 1984-07-20 1986-10-07 American Can Company Film and package having strong seals and a modified ply-separation opening
US4666778A (en) 1984-08-31 1987-05-19 Shell Oil Company Packaging film and sheet capable of forming peelable seals with good optics
US4737391A (en) 1984-12-03 1988-04-12 Viskase Corporation Irradiated multilayer film for primal meat packaging
US4875587A (en) 1985-02-21 1989-10-24 W. R. Grace & Co.-Conn. Easy open shrinkable laminate
CA1340037C (en) 1985-06-17 1998-09-08 Stanley Lustig Puncture resistant, heat-shrinkable films containing very low density polyethylene copolymer
US5128414A (en) 1985-06-28 1992-07-07 Shell Oil Company Polymer packaging film and sheet capable of forming peelable seals made from ethylenic and butene-1 polymers
US4784885A (en) 1986-08-29 1988-11-15 R. J. Reynolds Tobacco Company Peelable film laminate
US4937139A (en) 1987-04-30 1990-06-26 American National Can Company Peelable packaging and sheet materials and compositions for use therein
US4916190A (en) 1987-05-15 1990-04-10 Shell Oil Company Film and sheet capable of forming retortable and easy-open packagings
US4798751A (en) 1987-05-28 1989-01-17 Viskase Corporation Heat shrinkable multilayer film for primal meat packaging
US4882229A (en) 1988-04-29 1989-11-21 Shell Oil Company Blends of high molecular weight polybutylene with low density polyethylene
US5547752A (en) 1988-06-20 1996-08-20 James River Paper Company, Inc. Blend of polybutylene and ionomer forming easy-open heatseal
US5023121A (en) 1990-04-12 1991-06-11 W. R. Grace & Co.-Conn. Coextruded film with peelable sealant
US5302402A (en) 1992-11-20 1994-04-12 Viskase Corporation Bone-in food packaging article
CA2120895C (en) 1993-04-09 1999-03-30 David Nicholas Edwards Cheese package, film, bag and process for packaging a co2 respiring foodstuff
DK170114B1 (en) 1993-05-05 1995-05-29 Raackmanns Fab As Bag packaging made of flexible packaging material and method of making it
DE19548789A1 (en) 1995-12-27 1997-07-03 Hoechst Trespaphan Gmbh Peelable, sealable polyolefinic multilayer film, process for its preparation and its use
US5759648A (en) 1996-07-05 1998-06-02 Viskase Corporation Multilayer plastic film, useful for packaging a cook-in foodstuff
US5928740A (en) 1997-02-28 1999-07-27 Viskase Corporation Thermoplastic C2 -α-olefin copolymer blends and films
US6015235A (en) 1997-03-07 2000-01-18 Curwood, Inc. Puncture-resistant barrier pouch
US6790468B1 (en) * 1997-09-30 2004-09-14 Cryovac, Inc. Patch bag and process of making same
ES2213365T3 (en) 1998-04-16 2004-08-16 Cryovac, Inc. Ternary polymer blend, laminary element containing it and easy opening packaging manufactured with it.
US6355287B2 (en) * 1998-06-22 2002-03-12 Cryovac, Inc. Packaged food product having added liquid
US6004599A (en) 1998-08-10 1999-12-21 Viskase Corporation Bag for packaging bone-in cuts of meat
US6224410B1 (en) * 2000-04-04 2001-05-01 Chuan-Ying Chen Structure of a copper head socket for a light bulb
FR2841223B1 (en) * 2002-06-19 2004-10-15 Sleever Int Packaging for objects (s) of heat shrinkable material with essentially smooth internal or external side
WO2007088005A1 (en) 2006-01-31 2007-08-09 Cryovac, Inc. Hermetically sealable, easy-openable, flexible container of heat-shrinkable thermoplastic material

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01124558A (en) * 1987-10-30 1989-05-17 Idemitsu Petrochem Co Ltd Multi-layer bag
US4944409A (en) * 1988-02-10 1990-07-31 Curwood, Inc. Easy open package
EP0435498A2 (en) * 1989-12-08 1991-07-03 W.R. Grace &amp; Co.-Conn. High shrink energy/high modulus thermoplastic multi-layer packaging film and bags made therefrom
US6221410B1 (en) * 1992-09-25 2001-04-24 Cryovac, Inc. Backseamed casing and packaged product incorporating same
US5888648A (en) * 1996-09-12 1999-03-30 Mobil Oil Corporation Multi-layer hermetically sealable film and method of making same
JP2000142724A (en) * 1998-11-09 2000-05-23 Toppan Printing Co Ltd Easily unsealable bag-shaped packaging body
JP2002146343A (en) * 2000-08-22 2002-05-22 Mitsui Chemicals Inc Sealant resin composition, sealant film and its use

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006038700A1 (en) * 2004-10-04 2006-04-13 Kyoraku Co., Ltd. Filling-packaging body
US8142078B2 (en) 2004-10-04 2012-03-27 Kyoraku Co., Ltd. Material-filled package
US7279206B2 (en) * 2005-03-22 2007-10-09 Curwood, Inc. Packaging laminates and articles made therefrom
JP2008280089A (en) 2007-05-01 2008-11-20 Kraft Foods Holdings Inc Ingredient package and method
JP2012245990A (en) * 2011-05-26 2012-12-13 Kyoraku Co Ltd Packaging bag

Also Published As

Publication number Publication date
AU2004200759A1 (en) 2004-09-09
EP1449787B1 (en) 2009-05-06
NO20040765L (en) 2004-08-23
BRPI0402590A (en) 2004-11-30
AU2004200759B2 (en) 2009-11-05
EP1449787B2 (en) 2015-03-04
CA2458136C (en) 2012-01-03
JP4750367B2 (en) 2011-08-17
CA2458136A1 (en) 2004-08-20
NZ531295A (en) 2005-11-25
EP1449787A1 (en) 2004-08-25
PL365437A1 (en) 2004-08-23
IL160470D0 (en) 2004-07-25
IL160470A (en) 2010-05-17

Similar Documents

Publication Publication Date Title
US20170036426A1 (en) Multilayer barrier structures, methods of making the same and packages made therefrom
US20170036427A1 (en) Multilayer structures, packages, and methods of making multilayer structures
EP0875372B1 (en) Polyolefin stretch film
AU667768B2 (en) Packaging material for long-term storage of food products
EP0164232B2 (en) Multi-layer sheet structure for packaging, a package made therefrom, and a method of making the said structure
US6630237B2 (en) Peelably sealed packaging
US8178210B2 (en) Multilayer oriented high-modulus film
JP2733249B2 (en) Thermoplastic multilayer heat shrinkable packaging film and method for producing the same
DK166408B1 (en) Polymer multilevel movie and procedure for manufacturing the same and packaging manufactured thereof
EP0885115B1 (en) Method to achieve easy-opening flexible packaging laminates and packaging materials made therefrom
DE19549799B4 (en) Homogeneous ethylene-α-olefin copolymer-containing patch bag
EP1368229B1 (en) Heat shrinkable barrier bags with anti block additives
US4064296A (en) Heat shrinkable multi-layer film of hydrolyzed ethylene vinyl acetate and a cross-linked olefin polymer
EP0305959B1 (en) Multilayer film containing amorphous nylon
AU730200B2 (en) Hermetically sealed package, and method and machine for manufacturing it
US4391862A (en) Pasteurizable thermoplastic film and receptacle therefrom
DE69535285T2 (en) Films with welding properties and packaging containing them
EP0598017B1 (en) Pouch for packaging flowable materials
EP0236099B1 (en) Oxygen barrier packaging film
CA1303473C (en) Thermoplastic multilayer packaging film and bags made therefrom
EP0595270B1 (en) Heat sealable shrink laminate
AU612699B2 (en) Biaxially oriented multiplayer barrier films and methods of making
CA1113371A (en) Self-welding packaging film
CA1283268C (en) Thermoplastic multi-layer barrier packaging film and bags made therefrom
US7048125B2 (en) Patch bag having patch covering seal

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20070220

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20070220

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20071101

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20091215

RD04 Notification of resignation of power of attorney

Free format text: JAPANESE INTERMEDIATE CODE: A7424

Effective date: 20100315

RD02 Notification of acceptance of power of attorney

Free format text: JAPANESE INTERMEDIATE CODE: A7422

Effective date: 20100315

A601 Written request for extension of time

Free format text: JAPANESE INTERMEDIATE CODE: A601

Effective date: 20100315

A602 Written permission of extension of time

Free format text: JAPANESE INTERMEDIATE CODE: A602

Effective date: 20100323

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20100615

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20101102

A601 Written request for extension of time

Free format text: JAPANESE INTERMEDIATE CODE: A601

Effective date: 20110202

A602 Written permission of extension of time

Free format text: JAPANESE INTERMEDIATE CODE: A602

Effective date: 20110207

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20110223

A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20110510

A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20110519

R150 Certificate of patent or registration of utility model

Free format text: JAPANESE INTERMEDIATE CODE: R150

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20140527

Year of fee payment: 3

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

LAPS Cancellation because of no payment of annual fees