CN115674841A - Multilayer structure film - Google Patents
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- CN115674841A CN115674841A CN202211436094.8A CN202211436094A CN115674841A CN 115674841 A CN115674841 A CN 115674841A CN 202211436094 A CN202211436094 A CN 202211436094A CN 115674841 A CN115674841 A CN 115674841A
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Abstract
The present invention relates to a multilayer structure film comprising at least a first polyethylene layer, a second polyethylene layer, a first polyamide layer and a second polyamide layer coextruded and bonded together, wherein at least one of the first polyamide layer and the second polyamide layer is located between the first polyethylene layer and the second polyethylene layer. The invention also relates to a preparation method and application of the multilayer structure film.
Description
The present application is a divisional application of chinese patent application having an application date of 2014, 12/10, and an application number of 201410758223.4, entitled "multilayer structure film".
Technical Field
The present invention relates to a multilayer structure film. In particular, the present invention relates to a multilayer film useful for food packaging, especially for packaging of particulate matter (e.g., rice). The invention also relates to a preparation method and application of the multilayer structure film.
Background
Plastic packaging films are known in the food packaging field for their lightness and sealability. In the aspect of packaging granular substances such as rice and the like, plastic packaging bags are popular because the plastic packaging bags are superior to traditional woven bags in appearance, moisture resistance and insect prevention. Furthermore, due to the hermeticity of the plastic packaging film, a vacuuming process can be performed, thereby further reducing the volume of the contained substances such as rice and prolonging the shelf life thereof.
Rice imposes higher requirements on the packaging film due to its particularity. For example, rice grains are generally oblong or elongated in shape and their tips are very apt to pierce the packaging film. Various multilayer structure films have been developed for packaging of rice. Common structures include a nylon/polyethylene (NY/PE) composite structure, a nylon/chlorinated polyethylene (NY/CPE) composite structure, a nylon/polyethylene (NY/PE) multilayer co-extrusion structure, a polyethylene/polyethylene (PE/PE) composite structure, and the like. NY/PE or NY/CPE composite construction and PE/PE composite construction generally have the problem of not enduring puncture and resistant drop nature poor after the evacuation. NY/PE multilayer coextruded structures have relatively good puncture resistance, but typically require very thick PE sealing layers, for example at least 110 to 130 μm thick.
Accordingly, there remains a need for an improved multilayer film for packaging particulate matter such as rice, which should have, inter alia, good puncture resistance, and also good strength and/or oxygen barrier properties, and preferably maintain the desired packaging results with less thickness and/or lower material costs.
Disclosure of Invention
In a first aspect, the present invention relates to a multilayer structure film comprising at least a first polyethylene layer, a second polyethylene layer, a first polyamide layer and a second polyamide layer coextruded and bonded together, wherein at least one of the first polyamide layer and the second polyamide layer is located between the first polyethylene layer and the second polyethylene layer.
In a second aspect, the present invention is directed to a multilayer structure film comprising at least an outer polyamide layer and first, second, first and second polyethylene layers coextruded and bonded together, wherein at least one of the first and second polyamide layers is positioned between the first and second polyethylene layers, the outer polyamide layer being bonded to at least one of the first, second, first and second polyethylene layers to form a composite film.
In a third aspect, the present invention is directed to a method of making a multilayer structure film comprising coextruding and bonding together at least a first polyethylene layer, a second polyethylene layer, a first polyamide layer, and a second polyamide layer, wherein at least one of the first polyamide layer and the second polyamide layer is positioned between the first polyethylene layer and the second polyethylene layer.
In a fourth aspect, the present invention relates to the use of a multilayer structured film for the manufacture of packaging bags.
Drawings
The present invention is explained in detail by the following detailed description and the accompanying drawings so that those skilled in the art can better understand the present invention, but it should not be construed as limiting the scope of the present invention in any way. It is to be noted that the positions and thicknesses of the respective layers in the multilayer-structured film of the present invention may be adjusted as necessary, and are not necessarily in accordance with or proportional to the positions and thicknesses shown in the drawings.
Fig. 1 shows a cross-sectional view of a multilayer structure film comprising a first polyethylene layer, a first polyamide layer, a second polyamide layer and a second polyethylene layer according to one embodiment of the present invention.
Fig. 2 shows a cross-sectional view of a multilayer structure film comprising a first polyethylene layer, a first polyamide layer, a second polyamide layer and a second polyethylene layer bonded together in this order by tie layers according to another embodiment of the present invention.
Fig. 3 shows a cross-sectional view of a multilayer structure film comprising a first polyethylene layer, a first polyamide layer, a second polyamide layer and a second polyethylene layer, wherein the first polyethylene layer and the second polyethylene layer each comprise two polyethylene sublayers, the first polyethylene layer, the first polyamide layer, the second polyamide layer and the second polyethylene layer being sequentially bonded together by a tie layer, according to yet another embodiment of the present invention.
Fig. 4 shows a cross-sectional view of a multi-layer structural film comprising a first polyethylene layer, a first polyamide layer, a second polyethylene layer and an outer polyamide layer, wherein the first polyethylene layer and the second polyethylene layer each comprise two polyethylene sub-layers, the first polyethylene layer, the first polyamide layer, the second polyamide layer and the second polyethylene layer are sequentially bonded together by a tie layer, and the first polyethylene layer is bonded to the outer polyamide layer by an adhesive layer, according to yet another embodiment of the present invention.
Detailed Description
Numerical ranges herein include all values from the lower value to the upper value in increments of one unit and including both the lower value and the upper value. For example, if a numerical range is 100 to 500, then it should be considered that all individual values, e.g., 100, 101, 102 … … 498, 499, have been listed one by one, and that all subranges, e.g., 100 to 144, 155 to 170, 197 to 200, 268-390, 420-500, etc., are listed.
The term "composition", as used herein, refers to a mixture of two or more materials. Included in the composition are pre-reaction, reaction and post-reaction mixtures, wherein the post-reaction mixture will include reaction products and by-products as well as unreacted components of the reaction mixture and decomposition products, if present, formed from one or more components of the pre-reaction or reaction mixture.
As used herein, the terms "blend," "polymer blend," and "polymer blend" refer to a composition of two or more polymers. Such blends may or may not be miscible. Such blends may be homogeneous or heterogeneous, with or without phase separation.
Multilayer structure film
The present invention provides a multilayer structure film having excellent puncture resistance by coextruding at least two polyethylene layers and at least two polyamide layers.
Referring to fig. 1, a multilayer structure film 10 according to one embodiment of the present invention includes a first polyethylene layer 102 and a second polyethylene layer 108, wherein the first polyethylene layer 102 and the second polyethylene layer 108 have a first polyamide layer 104 and a second polyamide layer 104 therebetween, each layer being sequentially bonded together.
Suitably, the first polyethylene layer 102 and the second polyethylene layer 108 may each independently be selected from the group consisting of Low Density Polyethylene (LDPE), linear Low Density Polyethylene (LLDPE), medium Density Polyethylene (MDPE), high Density Polyethylene (HDPE), ultra low density polyethylene (VLLDPE), ultra High Molecular Weight Polyethylene (UHMWPE), metallocene polyethylene (mPE) (e.g. metallocene linear low density polyethylene (mLLDPE)), modified polyethylene (e.g. Chlorinated Polyethylene (CPE)), cross-linked Polyethylene (PEX), ethylene copolymers, and any mixtures thereof. The ethylene copolymer may be selected from, for example, ethylene-olefin copolymers (e.g., copolymers of ethylene with propylene, butene, pentene, hexene, heptene, octene, nonene, decene, cycloolefins, or any combination thereof), ethylene-unsaturated ester copolymers (e.g., copolymers of ethylene with methyl methacrylate, ethyl methacrylate, vinyl acetate, methyl acrylate, ethyl acrylate, maleic anhydride, or any combination thereof), and any mixtures thereof.
In a preferred embodiment, the first polyethylene layer 102 and the second polyethylene layer 108 each independently comprise Low Density Polyethylene (LDPE), linear Low Density Polyethylene (LLDPE), medium Density Polyethylene (MDPE), high Density Polyethylene (HDPE), ultra low density polyethylene (VLLDPE), ultra High Molecular Weight Polyethylene (UHMWPE), metallocene linear low density polyethylene (mLLDPE), or any mixture thereof.
The first polyethylene layer 102 and the second polyethylene layer 108 may each independently comprise a blend of LDPE and LLDPE. In one embodiment, at least one of the first and second polyethylene layers is substantially a blend of LDPE and LLDPE. The blend of LDPE and LLDPE may comprise at least 10% LDPE, preferably at least 15%, more preferably at least 20%, even more preferably at least 25% LDPE, based on the total weight of the blend. The blend of LDPE and LLDPE may comprise at most 70% LDPE, preferably at most 60%, more preferably at most 50%, even more preferably at most 40% LDPE, based on the total weight of the blend. The blend of LDPE and LLDPE may comprise at least 30% LLDPE, preferably at least 35%, more preferably at least 40%, even more preferably at least 45% LLDPE, based on the total weight of the blend. The blend of LDPE and LLDPE may comprise at most 90% LLDPE, preferably at most 80%, more preferably at most 70%, even more preferably at most 60% LDPE, based on the total weight of the blend. In a particular embodiment, the blend of LDPE and LLDPE comprises 10 to 30% LDPE and 70 to 90% LLDPE, based on the total weight of the blend. In another embodiment, the blend of LDPE and LLDPE comprises 20 to 40% LDPE and 60 to 80% LLDPE, based on the total weight of the blend.
Further, the first polyethylene layer 102 and the second polyethylene layer 108 may also each independently comprise a blend of LDPE, mLLDPE and LLDPE. Preferably, at least one or both of the first and second polyethylene layers is substantially a blend of LDPE, mLLDPE and LLDPE. Blends of LDPE, mLLDPE and LLDPE are believed to provide good puncture resistance to the multilayer structure film of the present invention while maintaining other desirable properties such as oxygen barrier, softness, toughness, etc. The desired balance of properties can be obtained by adjusting the ratio between LDPE, mLLDPE and LLDPE. For example, the blend of LDPE, mLLDPE and LLDPE may comprise at least 20% LLDPE, preferably at least 25%, more preferably at least 30%, even more preferably at least 35% LLDPE, based on the total weight of the blend. The blend of LDPE, mLLDPE and LLDPE may comprise at most 90% LLDPE, preferably at most 80%, more preferably at most 70%, even more preferably at most 60% LLDPE, based on the total weight of the blend. In another aspect, the blend of LDPE, mLLDPE and LLDPE may comprise at most 50% LDPE, preferably at most 45%, more preferably at most 35%, even more preferably at most 30% LDPE, based on the total weight of the blend. The blend of LDPE, mLLDPE and LLDPE may comprise at least 5% LDPE, preferably at least 10%, more preferably at least 15%, even more preferably at least 18% LDPE, based on the total weight of the blend. In yet another aspect, the blend of LDPE, mLLDPE and LLDPE comprises at most 90% mLLDPE, preferably at most 80%, more preferably at most 70%, even more preferably at most 65% mLLDPE, based on the total weight of the blend. The blend of LDPE, mLLDPE and LLDPE may comprise at least 10% mLLDPE, preferably at least 20%, more preferably at least 30%, even more preferably at least 35% mLLDPE, based on the total weight of the blend. In a particular embodiment, the blend of LDPE, mLLDPE and LLDPE comprises 15 to 25% LDPE, 15 to 25% mLLDPE and 50 to 70% LLDPE, based on the total weight of the blend. In another embodiment, the blend of LDPE, mLLDPE and LLDPE comprises 15 to 25% LDPE, 40 to 60% mLLDPE and 25 to 40% LLDPE, based on the total weight of the blend.
Suitably, the first polyamide layer 104 and the second polyamide layer 106 may each independently employ a polyamide (nylon) commonly used in the art for preparing polymer films, including, for example, nylon 6, nylon 66, nylon 6/66, nylon 10/10, nylon 12, nylon MX-D6, amorphous nylon, or any mixture thereof. The amorphous nylon may be a nylon copolymer or a blend of one or more nylons. In a preferred embodiment, the first polyamide layer 104 and the second polyamide layer 106 each independently comprise nylon 6. In another preferred embodiment, the first polyamide layer 104 and the second polyamide layer 106 each independently comprise nylon 66. In yet another preferred embodiment, at least one or both of the first polyamide layer 104 and the second polyamide layer 106 consists essentially of nylon 6.
The inventors have surprisingly found that two or more layers of polyamide provide better puncture resistance than one layer of polyamide, at the same total thickness and material composition. Preferably, at least one of the first and second polyamide layers is located between the first and second polyethylene layers. In a particular embodiment, one or both of the first and second polyamide layers are positioned between the first and second polyethylene layers. In the multilayer structural film 10 shown in fig. 1, both the first polyamide layer 104 and the second polyamide layer 106 are located between the first polyethylene layer 102 and the second polyethylene layer 108. In further embodiments, the multilayer structure film may further comprise more polyamide layers in addition to the first and second polyamide layers. For example, in one embodiment, the multilayer structure film may comprise three, four, five or more polyamide layers, wherein at least one, two or three of the polyamide layers are located between the first and second polyethylene layers.
The first polyethylene layer 102, first polyamide layer 104, second polyamide layer 106 and second polyethylene layer 108 may be bonded together by any suitable means. Possible ways include surface treatment of the individual layers to make them adhere naturally, also by coextrusion under elevated temperature and natural adhesion after cooling, and also by bonding together of tie layers.
In an alternative embodiment, the positions of the first polyethylene layer 102 and the first polyamide layer 104 may be interchanged, or the positions of the second polyethylene layer 108 and the second polyamide layer 106 may be interchanged.
Fig. 2 shows a multilayer structural film 20 according to another embodiment of the present invention comprising a first polyethylene layer 202, a first polyamide layer 206, a second polyamide layer 210, and a second polyethylene layer 214, which are sequentially bonded together by tie layers 204, 208, and 212.
Tie layers suitable for bonding the first polyethylene layer 202, first polyamide layer 206, second polyamide layer 210 and second polyethylene layer 214 together may comprise low density polyethylene, linear low density polyethylene, metallocene linear low density polyethylene, acrylate acetate copolymer or anhydride modified polyethylene copolymer and any mixtures thereof. In a preferred embodiment, the tie layer comprises at least 50%, preferably 60%, more preferably 70% of linear low density polyethylene based on the total weight of the tie layer. In a preferred embodiment, the tie layer may comprise a maleic anhydride modified polyethylene copolymer or an ethylene-vinyl acetate copolymer. Additionally or alternatively, the tie layer may comprise any other polymeric adhesive conventionally used in the art of multilayer structural film production, preferably the adhesive is useful for food packaging. Specific examples of adhesives that may be used are the extrudable adhesives available under the trade designations Plexar, px3410, px3747, manufactured by Equistar chemical company, usa, which are particularly suitable for multilayer coextruded materials and have passed FDA approval for adhesives in the united states while also achieving limited approval for direct food contact.
In further embodiments, at least one of the first and second polyethylene layers may comprise two or more sub-layers of polyethylene laminated together. In a particular embodiment, the first polyethylene layer or the second polyethylene layer independently comprises two, three or four sub-layers of polyethylene laminated together.
Each polyethylene sub-layer may independently comprise Low Density Polyethylene (LDPE), linear Low Density Polyethylene (LLDPE), medium Density Polyethylene (MDPE), high Density Polyethylene (HDPE), ultra low density polyethylene (VLLDPE), ultra High Molecular Weight Polyethylene (UHMWPE), metallocene linear low density polyethylene (mLLDPE) or any mixture thereof. For example, each polyethylene sub-layer may each independently be a blend of LDPE, mLLDPE and LLDPE or a blend of LDPE and LLDPE as described above.
Fig. 3 shows a cross-sectional view of a multilayer structure film 30 comprising a first polyethylene layer 301, a first polyamide layer 308, a second polyamide layer 312, and a second polyethylene layer 315 according to yet another embodiment of the present invention, wherein the first polyethylene layer 301 comprises two polyethylene sublayers 302 and 304 and the second polyethylene layer 315 comprises two polyethylene sublayers 316 and 318, said first polyethylene layer 301, first polyamide layer 308, second polyamide layer 312, and second polyethylene layer 315 being bonded together in sequence by tie layers 306, 310, and 314.
Preferably, said first polyethylene layer 301 and said second polyethylene layer 315 each independently comprise two, three, four, five or six sub-layers of polyethylene laminated together. The thickness of the polyethylene sub-layers may be adjusted depending on the desired total thickness of the first or second polyethylene layers and the number of polyethylene sub-layers, and the thickness of each polyethylene sub-layer may be the same or different. In a preferred embodiment, each polyethylene sublayer has a thickness of at most 40 μm, preferably at most 30 μm, more preferably at most 20 μm, even more preferably at most 15 μm or 10 μm.
In a still further embodiment, the multilayer structure film of the present invention further comprises an outer polyamide layer combined with at least one of the first polyethylene layer, the second polyethylene layer, the first polyamide layer and the second polyamide layer to form a composite film. In a preferred embodiment, the outer polyamide layer is bonded to at least one of the first polyethylene layer, the second polyethylene layer, the first polyamide layer and the second polyamide layer by an adhesive to form a composite film.
Fig. 4 shows a cross-sectional view of a multilayer structural film 40 comprising an outer polyamide layer 402, a first polyethylene layer 405, a first polyamide layer 412, a second polyamide layer 416 and a second polyethylene layer 419, wherein the first polyethylene layer 405 comprises two polyethylene sublayers 406 and 408 and the second polyethylene layer 419 comprises two polyethylene sublayers 420 and 422, said first polyethylene layer 405, first polyamide layer 412, second polyamide layer 416 and second polyethylene layer 419 being bonded together in sequence by tie layers 410, 414 and 418, said outer polyamide layer 402 being bonded to said polyethylene sublayer 406 of said first polyethylene layer 405 by an adhesive layer 404, according to a further embodiment of the present invention.
The polyamide outer layer may employ various polyamides (nylons) commonly available in the art for forming outer layers of multilayer film structures, including, for example, nylon 6, nylon 66, nylon 6/66, nylon 10/10, nylon 12, nylon MX-D6, amorphous nylon, or any mixtures thereof. The amorphous nylon may be a nylon copolymer or a blend of one or more nylons. In a preferred embodiment, the polyamide outer layer 402 consists essentially of nylon 6. In another preferred embodiment, the polyamide outer layer 402 consists essentially of nylon 66. In yet another preferred embodiment, the polyamide outer layer 402 consists essentially of nylon MX-D6.
The polyamide outer layer 402 may be a uniaxially or biaxially oriented polyamide (nylon) film, preferably a biaxially oriented polyamide (nylon) film. Optionally, the bonding side of the outer polyamide layer 402 may be surface treated to enhance its adhesion, which may include one or more of corona treatment, plasma treatment, actinic radiation, flash lamp treatment, flame treatment.
The adhesive layer 404 suitable for bonding the polyamide outer layer 402 to the first polyethylene layer 405 may employ any adhesive commonly used in the art, such as vinyl acetate-ethylene copolymer-based adhesives, polyacrylate-based adhesives, polyurethane-based adhesives, epoxy-based adhesives, and the like. Polyurethane-based adhesives are particularly useful in the present invention for bonding together polyamide and polyethylene layers of different properties to provide a multilayer structure film having excellent puncture resistance. Polyurethane adhesives that may be used include, but are not limited to, water-based polyurethane adhesives, hot melt polyurethane adhesives, solvent-based polyurethane adhesives, solventless polyurethane adhesives. The polyurethane adhesive can be a single-component adhesive or a two-component adhesive. In one embodiment, the adhesive layer 404 employs a two-part polyurethane-based adhesive. The double-component polyurethane adhesive consists of a component A and a component B, and when the adhesive is used, the two components are weighed and mixed according to different proportions according to a base material to be adhered, so that the adhesive can be adhered and can be cured at room temperature. The component A of the double-component polyurethane adhesive can be a linear product with a hydroxyl end group generated by copolymerizing linear polyurethane and isocyanate, and the component B can be a prepolymer with an isocyanate end group generated by reacting isocyanate and polyalcohol. The double-component polyurethane adhesive has good adhesiveness, flexibility, insulativity and wear resistance, can resist weak acid, and is particularly suitable for food packaging. In another embodiment, the adhesive layer 404 employs a two-part adhesive comprising a hydroxyl-terminated polyester urethane as a major component.
The thickness of the polyamide outer layer depends on the thickness of the entire multilayer structure film, and is at most 50% of the thickness of the multilayer structure film, generally between 5 and 40%, preferably between 10 and 30%, more preferably between 15 and 25% of the thickness of the multilayer structure film.
In order to give the obtained multilayer structure film a specific appearance, a coloring pigment or a pattern may be contained in each layer. For example, a specific color or pattern for identification purposes may be included in the outer polyamide layer. Optionally, various ingredients that can improve the added value of the multilayer structure film, such as UV stabilizers, antioxidants, and the like, may also be added to the respective layers as necessary, as long as these ingredients do not significantly impair desired properties, such as puncture resistance, strength, oxygen barrier properties, and the like.
The multilayer structure film according to the present invention can provide better puncture resistance at a thinner thickness than the prior art. The thickness of the multilayer-structured film according to the present invention can be adjusted as desired. Typically, the multilayer structure film according to the present invention may have a thickness of 10 to 200 μm, preferably 20 to 180 μm, more preferably 30 to 150 μm, for example 50 to 120 μm or 60 to 100 μm or 40 to 80 μm or 70 to 110 μm as a whole when used as a food packaging bag for granular matters such as rice.
When the multilayer structure film according to the present invention was subjected to a performance test, it was found that the multilayer structure film according to the present invention is comparable to the conventional multilayer structure film having a larger thickness in all of the properties tested, such as heat seal strength, tensile properties, coefficient of friction, etc., and is significantly superior to the conventional multilayer structure film in oxygen barrier properties, drop resistance properties and pendulum impact resistance properties. In addition, the multi-layer structure film provided by the invention has the peel strength capable of meeting the use requirements of common packages, and the delamination phenomenon can not occur in normal use.
Method for producing multilayer-structured film
The multilayer structure film according to the present invention may be prepared by any suitable method, for example by die coextrusion, extrusion coating and/or film extrusion lamination, adhesive lamination, blown film coextrusion, and the like.
In order to more greatly exert the advantages of the multilayer structure film according to the present invention, the multilayer structure film of the present invention may be prepared by, but is not limited to, the following method: coextruding and bonding together at least a first polyethylene layer, a second polyethylene layer, a first polyamide layer, and a second polyamide layer, wherein at least one of the first polyamide layer and the second polyamide layer is located between the first polyethylene layer and the second polyethylene layer.
In a preferred embodiment, the process of the present invention provides a process for making a multilayer structure film comprising coextruding and bonding together at least a first polyethylene layer, a second polyethylene layer, a first polyamide layer and a second polyamide layer, wherein at least one of the first polyamide layer and the second polyamide layer is positioned between the first polyethylene layer and the second polyethylene layer, and a tie layer.
Coextrusion is a well known technique in the art and may for example comprise the steps of: with multilayer coextrusion film equipment, multiple molten polymer compositions are blown, cast, extruded and laminated together in the molten state at the die exit, while gradually cooling, after undergoing complex interactions of stretching, orientation and crystallization, to a crimping device.
Other multilayer structure film fabrication techniques suitable for use in the present invention can be found in the following documents: the Encyclopedia of Chemical Technology, kirk-Othmer, third edition, john Wiley & Sons, new York,1981, volume 16, pages 416-417 and volume 18, pages 191-192; packing Foods With Plastics, wilmer A.Jenkins and James P.Harrington, (1991), pages 19-27; "Coextusion bases" by Thomas I.Butler, film Extrusion Manual: process, materials, properties, pages 31-80 (published by TAPPI Press (1992)); schrenk and C.R.Finch, "Cooxtrusion For Barrier Packaging", society of Plastics Engineers RETEC Proceedings, june, 15-17 (1981), pp.211-229; osborn and w.a.jenkins; and Plastic Films, technology and Packaging Applications (technical Publishing co., inc., 1992)), which are hereby incorporated by reference in their entirety.
The outer polyamide layer and the multilayer coextruded film comprising at least the first polyethylene layer, the second polyethylene layer, the first polyamide layer and the second polyamide layer may be compounded by a dry compounding process well known to those skilled in the art, and may include, for example, coating an adhesive on the surface of the outer polyamide layer and/or the multilayer coextruded film using a dry compounding machine, coating both surfaces and curing with heat.
Use of multilayer structure film
The multilayer structure film according to the present invention can be used for various purposes, particularly for applications requiring puncture resistance. In one embodiment, the multilayer structure film of the present invention can be used to prepare a packaging bag. The package may be used to contain liquid or solid substances. The solid substance may be selected from one or more of a block, granular and powdered substance. Lumpy materials such as stones, wood pieces, metal pieces, food pieces (e.g., salad pieces), and the like. Granular materials such as sand, plant seeds (such as sunflower seed, watermelon seed, etc.), seasonings (such as anise, pepper, etc.), rice, millet, corn, beans, etc. Powdered substances such as flour, milk powder, bean powder, etc. In a particular embodiment, the package is used for packaging a substance selected from rice, millet, corn, salad, flour or any mixture thereof. The multilayer-structured film of the present invention and a packaging bag made therefrom can be used for vacuum packaging or gas packaging. In one embodiment, the multilayer film of the present invention is particularly useful for vacuum packaging of sharp tipped materials such as rice due to its excellent puncture resistance.
Thus, the present invention provides at least the following:
1. a multilayer structural film comprising at least a first polyethylene layer, a second polyethylene layer, a first polyamide layer, and a second polyamide layer coextruded and bonded together, wherein at least one of the first polyamide layer and the second polyamide layer is located between the first polyethylene layer and the second polyethylene layer.
2. The multilayer structural film of item 1, wherein the first polyethylene layer and the second polyethylene layer are each independently selected from the group consisting of low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, ultra low density polyethylene, ultra high molecular weight polyethylene, metallocene linear low density polyethylene, chlorinated polyethylene, crosslinked polyethylene, ethylene copolymers, and any mixtures thereof.
3. The multilayer structural film of item 2, wherein at least one of the first and second polyethylene layers is a blend of low density polyethylene, metallocene linear low density polyethylene, and linear low density polyethylene.
4. The multilayer structural film of item 3, wherein the blend of low density polyethylene, metallocene linear low density polyethylene, and linear low density polyethylene comprises at least 20% linear low density polyethylene based on the total weight of the blend.
5. The multilayer structural film of item 3, wherein the blend of low density polyethylene, metallocene linear low density polyethylene, and linear low density polyethylene comprises at least 5% low density polyethylene based on the total weight of the blend.
6. The multilayer structural film of item 3, wherein the blend of low density polyethylene, metallocene linear low density polyethylene, and linear low density polyethylene comprises at least 10% metallocene linear low density polyethylene based on the total weight of the blend.
7. The multilayer structural film of item 3, wherein the blend of low density polyethylene, metallocene linear low density polyethylene, and linear low density polyethylene comprises 15 to 25% low density polyethylene, 40 to 60% metallocene linear low density polyethylene, and 25 to 40% linear low density polyethylene, based on the total weight of the blend.
8. The multilayer structural film of item 1, wherein the individual layers are bonded together by a tie layer comprising at least 50% linear low density polyethylene based on the total weight of the tie layer.
9. The multilayer structural film of any of items 1-8, wherein at least one of the first and second polyethylene layers comprises two or more sub-layers of polyethylene laminated together, each of the sub-layers of polyethylene having a thickness of at most 30 μm.
10. The multilayer structural film of item 1, further comprising an outer polyamide layer combined with at least one of the first polyethylene layer, the second polyethylene layer, the first polyamide layer, and the second polyamide layer to form a composite film.
11. The multilayer structural film of item 10, wherein the outer polyamide layer is bonded to at least one of the first polyethylene layer, the second polyethylene layer, the first polyamide layer, and the second polyamide layer by an adhesive to form a composite film.
12. The multilayer structure film of item 10 or 11, wherein the polyamide outer layer is composed of a biaxially oriented polyamide.
13. The multilayer structure film of item 11, wherein the adhesive is a two-part adhesive comprising a hydroxyl-terminated polyester urethane as a main component.
14. The multilayer structure film of item 10 or 11, wherein the polyamide outer layer has a thickness of between 5 to 40% of the total thickness of the multilayer structure film.
15. A method of making the multilayer structural film according to any of items 1-14, comprising co-extruding and bonding together at least a first polyethylene layer, a second polyethylene layer, a first polyamide layer, and a second polyamide layer, wherein at least one of the first polyamide layer and the second polyamide layer is positioned between the first polyethylene layer and the second polyethylene layer.
16. The method of item 15, comprising coextruding and bonding together at least the first polyethylene layer, the second polyethylene layer, the first polyamide layer, and the second polyamide layer through a tie layer.
17. Use of the multilayer structure film according to any one of items 1 to 14 for producing a packaging bag.
18. The use according to item 17, wherein the packaging bag is used for packaging one or more selected from the group consisting of a block-shaped, a granular-shaped and a powdery substance.
19. Use according to item 18, wherein the packaging bag is for packaging a substance selected from rice, millet, corn, salad, flour or any mixture thereof.
20. The use according to any one of items 17 to 19, wherein the packaging bag is used for vacuum packaging or gas packaging.
Examples
Some embodiments of the present invention will be explained below with reference to examples so that those skilled in the art can more clearly understand the technical solutions of the present invention and the advantages thereof, but the present invention is not limited in any way.
1. Material
Comparative and example samples of multilayer structure films were prepared using the following materials.
2. Preparation of multilayer-structured film
2.1 comparative example 1
The PE three-layer co-extrusion film with the thickness of 110 mu m is prepared by adopting ReifenHouser SW2200 type multi-layer co-extrusion film blowing equipment. The die temperatures for the layers were 220 ℃. The structure of the PE three-layer co-extrusion film, the composition of each layer and the layer thickness proportion based on the total thickness of the co-extrusion film are as follows:
the thickness of the double film was 15 μm using a dry lamination machine of model DL-S1300 from Sanxia TaiwanAxially oriented polyamide outer layer
B40L and the first layer in the PE three-layer co-extruded film are mixed by polyurethane adhesive XH-750E at 3.6g/m 2 The amount of sizing was adhered together and then cured at a temperature of 55 ℃ for 48h. The thickness of the polyurethane adhesive in the resulting multilayer film was 2 μm.
2.2 comparative example 2
The PE three-layer co-extrusion film with the thickness of 100 mu m is prepared by adopting ReifenHouser SW2200 type multi-layer co-extrusion film blowing equipment. The die temperatures for the layers were 220 ℃. The structure of the PE three-layer co-extrusion film, the composition of each layer and the layer thickness proportion based on the total thickness of the co-extrusion film are as follows:
an outer layer of biaxially oriented polyamide 15 μm thick was formed by a dry lamination machine of model DL-S1300 from Sanxia Taiwan
B40L and the first layer in the PE three-layer co-extruded film are mixed by polyurethane adhesive XH-750E at 3.6g/m 2 The amount of sizing was adhered together and then cured at a temperature of 55 ℃ for 48h. The thickness of the polyurethane adhesive in the obtained multilayer-structured film was 2 μm.
2.3 example 1
And preparing the PE/PA nine-layer co-extruded film with the thickness of 80 mu m by adopting ReifenHouser SW2200 type multi-layer co-extrusion film blowing equipment. The die temperatures for the layers were 220 ℃. The structure of the PE/PA nine-layer co-extruded film, the composition of each layer and the layer thickness proportion based on the total thickness of the co-extruded film are as follows:
an outer layer of biaxially oriented polyamide 15 μm thick was formed by a dry lamination machine of model DL-S1300 from Sanxia Taiwan
B40L and the first layer in the PE three-layer co-extruded film are mixed by polyurethane adhesive XH-750E at 3.6g/m 2 The amount of sizing was adhered together and then cured at a temperature of 55 ℃ for 48h. The thickness of the polyurethane adhesive in the resulting multilayer film was 2 μm.
2.4 example 2
And preparing the PE/PA nine-layer co-extruded film with the thickness of 80 mu m by adopting ReifenHouser SW2200 type multi-layer co-extrusion film blowing equipment. The die temperatures for the layers were 220 ℃. The structure of the PE/PA nine-layer co-extruded film, the composition of each layer and the layer thickness proportion based on the total thickness of the co-extruded film are as follows:
an outer layer of biaxially oriented polyamide 15 μm thick was formed by a dry lamination machine of model DL-S1300 from Sanxia Taiwan
B40L and the first layer in the PE three-layer co-extrusion film are bonded together through polyurethane adhesive XH-750E with the gluing amount of 3.6g/m, and then cured for 48 hours at the temperature of 55 ℃. The thickness of the polyurethane adhesive in the resulting multilayer film was 2 μm.
3. Performance testing
The multilayer structure films of comparative examples 1, 2 and examples 1, 2 above were subjected to various performance tests according to the requirements in GB/T10004-2008.
3.1 Fall Performance
The bags made from the multilayer structure films of comparative examples 1, 2 and examples 1, 2 above were subjected to a drop performance test. The vacuum test is performed because the puncture resistance of the packaging bag can be tested by vacuum pumping.
The test surface is a cement floor. The bag was filled with 5kg of rice and evacuated. When 6 surfaces of the package obtained after evacuation were each faced the test surface (cement floor), the package was allowed to freely fall from a specified height (1.5 m, 2.0 m, 2.5 m, 3.0 m), and air leakage or puncture was visually checked. The results are shown in Table 1.
Table 1 drop performance test results
The drop performance test results showed that the packaging bags prepared from the multi-layered structure films according to examples 1 and 2 of the present invention (each having a thickness of 80 μm +17 μm) could be free from the occurrence of air leakage or puncture even when dropped 3 times from a height of 2.0 meters, even 2.5 meters after vacuum-packaging rice, whereas comparative example 1, although having a greater thickness (110 μm +17 μm), had the occurrence of air leakage and puncture even when dropped from a height of 2.0 meters, and comparative example 2 (having a thickness of 100 μm +17 μm) had the occurrence of air leakage and puncture even when dropped from a height of 1.5 meters.
In other words, in a drop test with a height of 1.5 m or less, the conventional multilayer structure film has puncture and air leakage phenomena for 3 drops at 6 sides, and the bag breakage rate is 100%, whereas in a drop test with a height of 2 m or less, the bag breakage rate of the multilayer structure film of the present invention is 0%.
3.2 pendulum impact resistance
The multi-layer structure films of comparative examples 1 and 2 and examples 1 and 2 above were subjected to the Charpy impact resistance test according to GB/T8809-1988, and the results are shown in Table 2.
TABLE 2 pendulum impact resistance test results
| Anti-pendulum hammer impactImpact energy (J) | |
| Comparative example 1 | 1.73 |
| Comparative example 2 | 1.78 |
| Example 1 | 1.83 |
| Example 2 | 1.87 |
Examples 1 and 2 according to the present invention provide a multilayer structure film having a greater resistance to pendulum impact energy at a smaller thickness than comparative examples 1 and 2.
3.3 oxygen Barrier Properties
The multi-layered structure films of comparative examples 1, 2 and examples 1, 2 above were subjected to oxygen barrier performance test using coulometry in accordance with GB/T19789-2005, and the results are shown in Table 3.
Table 3 oxygen barrier performance test results
| Oxygen transmission rate (cm) 3 /(m 2 ·24h)) | |
| Comparative example 1 | 33.60 |
| Comparative example 2 | 31.36 |
| Example 1 | 13.56 |
| Example 2 | 16.52 |
From the oxygen transmission rate data in table 3, the multilayer structure films according to examples 1 and 2 of the present invention were only about one-half or less of the multilayer structure films of comparative examples 1 and 2. Thus, examples 1 and 2 according to the present invention provide significantly more excellent oxygen barrier properties at a smaller thickness than comparative examples 1 and 2.
3.4 Heat seal Strength
The bags made from the multilayer structure films of comparative examples 1, 2 and examples 1, 2 above were subjected to heat seal strength testing according to QB/T2358-1988. A bag of 510mm (length) × 310mm (width) was formed by folding a multilayer structure film of 1020mm (length) × 310mm (width) in half in the longitudinal direction and heat-sealing. The lengthwise heat seal is called a side heat seal, and the widthwise heat seal is called a top heat seal. The results of the heat seal strength measurements are shown in Table 4 below.
TABLE 4 Heat seal Strength test results
The multi-layered structure films according to examples 1 and 2 of the present invention showed more uniform and superior heat-seal strength at the top and side edges than those of comparative examples 1 and 2.
3.5 tensile Properties
Tensile property tests were performed on the multilayer structure films of comparative examples 1 and 2 and examples 1 and 2 according to GB/T1040.3-2006, and the resulting tensile force and elongation at break were as shown in Table 5.
TABLE 5 tensile Property test results
Note: the extrusion direction of the multilayer co-extruded film is the longitudinal direction.
The multi-layered structure films according to examples 1 and 2 of the present invention had comparable tensile strength and toughness to those of comparative examples 1 and 2.
3.6 coefficient of friction
The multi-layer structure films of comparative examples 1 and 2 and examples 1 and 2 above were subjected to a friction coefficient test according to GB/T10006-1988, and the results are shown in Table 6.
TABLE 6 Friction coefficient test results
| Coefficient of static friction | Coefficient of dynamic friction | |
| Comparative example 1 | 0.11 | 0.10 |
| Comparative example 2 | 0.15 | 0.11 |
| Example 1 | 0.15 | 0.12 |
| Example 2 | 0.11 | 0.08 |
The multi-layered structure films according to examples 1 and 2 of the present invention had comparable friction coefficients compared to comparative examples 1 and 2.
Although the present invention has been described in detail with reference to specific embodiments and presently preferred embodiments, those skilled in the art to which this invention pertains will appreciate that there are numerous variations and/or permutations of the above described structures and that such variations and/or permutations are included within the spirit and scope of the invention. It is to be understood that this invention is not limited to the particular construction and composition of components described herein. Variations and modifications based on the disclosure are also within the scope of the invention. It will also be understood that the invention disclosed herein extends to any combination of two or more of the features mentioned or evident from the text. All of these different combinations constitute various possible aspects of the present invention.
Claims (20)
1. A multilayer structure film comprising at least a first polyethylene layer, a second polyethylene layer, a first polyamide layer, and a second polyamide layer coextruded and bonded together, wherein at least one of the first polyamide layer and the second polyamide layer is located between the first polyethylene layer and the second polyethylene layer.
2. The multilayer structural film of claim 1, wherein said first polyethylene layer and said second polyethylene layer are each independently selected from the group consisting of low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, ultra low density polyethylene, ultra high molecular weight polyethylene, metallocene linear low density polyethylene, chlorinated polyethylene, crosslinked polyethylene, ethylene copolymers, and any mixtures thereof.
3. The multilayer structural film of claim 2, wherein at least one of said first polyethylene layer and said second polyethylene layer is a blend of low density polyethylene, metallocene linear low density polyethylene, and linear low density polyethylene.
4. The multilayer structural film of claim 3, wherein the blend of low density polyethylene, metallocene linear low density polyethylene, and linear low density polyethylene comprises at least 20% linear low density polyethylene based on the total weight of the blend.
5. The multilayer structural film of claim 3, wherein the blend of low density polyethylene, metallocene linear low density polyethylene, and linear low density polyethylene comprises at least 5% low density polyethylene based on the total weight of the blend.
6. The multilayer structural film of claim 3, wherein the blend of low density polyethylene, metallocene linear low density polyethylene, and linear low density polyethylene comprises at least 10% metallocene linear low density polyethylene based on the total weight of the blend.
7. The multilayer structural film of claim 3, wherein the blend of low density polyethylene, metallocene linear low density polyethylene, and linear low density polyethylene comprises 15 to 25% low density polyethylene, 40 to 60% metallocene linear low density polyethylene, and 25 to 40% linear low density polyethylene, based on the total weight of the blend.
8. The multilayer structural film of claim 1, wherein the individual layers are bonded together by a tie layer comprising at least 50% linear low density polyethylene based on the total weight of the tie layer.
9. The multilayer structural film of any of claims 1-8, wherein at least one of said first and second polyethylene layers comprises two or more sub-layers of polyethylene laminated together, each of said sub-layers of polyethylene having a thickness of at most 30 μm.
10. The multilayer structural film of claim 1, further comprising an outer layer of polyamide combined with at least one of the first polyethylene layer, the second polyethylene layer, the first polyamide layer, and the second polyamide layer to form a composite film.
11. The multilayer structural film of claim 10, wherein the outer polyamide layer is bonded to at least one of the first polyethylene layer, the second polyethylene layer, the first polyamide layer, and the second polyamide layer by an adhesive to form a composite film.
12. The multilayer structural film of claim 10 or 11, wherein said polyamide outer layer is comprised of biaxially oriented polyamide.
13. The multilayer structural film of claim 11, wherein the adhesive is a two-part adhesive comprising a hydroxyl-terminated polyester urethane as a main component.
14. The multilayer structural film of claim 10 or 11, wherein the thickness of the polyamide outer layer is between 5-40% of the total thickness of the multilayer structural film.
15. A method of making a multilayer structural film according to any of claims 1-14 comprising co-extruding and bonding together at least a first polyethylene layer, a second polyethylene layer, a first polyamide layer, and a second polyamide layer, wherein at least one of the first polyamide layer and the second polyamide layer is positioned between the first polyethylene layer and the second polyethylene layer.
16. The method of claim 15, comprising coextruding and bonding together at least the first polyethylene layer, the second polyethylene layer, the first polyamide layer, and the second polyamide layer through tie layers.
17. Use of a multilayer structured film according to any one of claims 1 to 14 for the production of packaging bags.
18. Use according to claim 17, wherein the packaging bag is used for packaging one or more selected from the group consisting of block, granular and powder materials.
19. Use according to claim 18, wherein the package is for packaging a substance selected from rice, millet, corn, salad, flour or any mixture thereof.
20. Use according to any one of claims 17 to 19, wherein the packaging bag is for vacuum packaging or gas packaging.
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| CN107344439B (en) * | 2017-05-08 | 2019-09-20 | 杭州巨杰包装科技有限公司 | A kind of high intensity five-layer co-squeezing composite membrane and preparation method thereof |
| CN107215528B (en) * | 2017-06-14 | 2019-12-31 | 朴德科技（杭州）有限公司 | Application of polyethylene polyamide composite film for carton handle |
| CN108750370B (en) * | 2018-06-19 | 2019-08-23 | 东莞奇妙包装有限公司 | A kind of flexible packaging film, a kind of soft packaging bag and preparation method thereof |
| CN110154478B (en) * | 2019-06-11 | 2022-01-18 | 福建富一锦科技有限公司 | Transparent milk packaging film and preparation method thereof |
| CN113059881B (en) * | 2021-05-08 | 2023-06-09 | 江阴市格瑞包装材料有限公司 | High-barrier acid-resistant packaging film and preparation method thereof |
| CN113696579A (en) * | 2021-09-03 | 2021-11-26 | 山东永聚医药科技有限公司 | High-barrier puncture-resistant membrane material for biopharmaceutical process and preparation process thereof |
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