Heat-shrinkable raffia fabric and methods for using the fabric

Abstract

A method for shrink wrapping two or more articles, comprising: providing a heat-shrinkable raffia fabric formed from warp and weft tapes, the warp and weft tapes comprising at least 70% by weight, based on the total weight percent of polymers present in the warp and weft tapes, of an ethylene / alpha-olefin copolymer having a density of 0.945 g / cc or greater and a melt index (I2) of 0.01 to 2.0 g / 10 min, as measured in accordance with ASTM D1238 (190°C, 2.16 kg); wrapping the two or more articles in the heat-shrinkable raffia fabric to form a wrapped bundle; and heating the wrapped bundle to form a shrink-wrapped bundle. [Selection diagram] None

Description

[Technical Field]

[0001] Embodiments of this disclosure generally relate to polyethylene-based heat-shrinkable fabrics and methods for using polyethylene-based heat-shrinkable fabrics. [Background technology]

[0002] Shrink packaging generally involves wrapping an item in shrink film to form the packaging, and then heat-shrinking the film by exposing it to enough heat to cause shrinkage and close contact between the film and the item. However, shrink film is not typically used in unitized packaging where heavier items (e.g., multiple boxes, cartons, packages, pails, etc.) are packaged together in a single load to facilitate handling, identification, and transport. Instead, corrugated cardboard is often used because it can provide cushioning and structural strength. Corrugated cardboard has its drawbacks. It has relatively low resistance to mechanical stress, is not waterproof, and can be very bulky.

[0003] Therefore, it is desirable to have alternative unitization and / or rugged packaging options. [Overview of the Initiative]

[0004] Disclosed in embodiments herein is a heat-shrinkable raffia fabric. The heat-shrinkable raffia fabric is formed from warp and weft tapes, the warp and weft tapes comprising at least 70% by weight of an ethylene / alpha-olefin copolymer having a density greater than 0.945 g / cc and a melt index (I2) of 0.01 to 2.0 g / 10 min.

[0005] Furthermore, embodiments of this specification also disclose a method for shrink-wrapping two or more articles. This method provides a heat-shrinkable raffia fabric formed from warp and weft tapes, wherein the warp and weft tapes contain at least 70% by weight of an ethylene / alpha-olefin copolymer having a density greater than 0.945 g / cc and a melt index (I2) of 0.01 to 2.0 g / 10 min; wrap two or more articles with the heat-shrinkable raffia fabric to form a wrapped bundle; and heat the wrapped bundle to form a shrink-wrapped bundle.

[0006] In one embodiment, the heat-shrinkable raffia fabric according to any of the embodiments described above is coated with a polyolefin resin. The polyolefin resin may comprise low-density polyethylene, linear low-density polyethylene, polypropylene, or a blend of two or more of low-density polyethylene, linear low-density polyethylene, or polypropylene. In some embodiments, the polyolefin resin comprises low-density polyethylene.

[0007] In one embodiment, the ethylene / alpha-olefin copolymer according to any of the embodiments described above has a density of 0.945 to 0.960 g / cc. In one embodiment, the ethylene / alpha-olefin copolymer according to any of the embodiments described above has a melt index (I2) of 0.1 to 1.5 g / 10 min, as determined according to ASTM D1238 (190°C, 2.16 kg). In one embodiment, the ethylene / alpha-olefin copolymer according to any of the embodiments described above has a melt flow ratio (I10 / 12) of 7.1 to 30.0. In one embodiment, the ethylene / alpha-olefin copolymer according to any of the embodiments described above has a Vicat softening temperature of 100°C to 140°C. In one embodiment, the ethylene / alpha-olefin copolymer according to any of the embodiments described above has a number average molecular weight (Mn) of 3.0 to 6.0.

number

[0008] In one embodiment, the warp and weft tapes according to any of the foregoing embodiments have a density of about 0.916 g / cm , , , 3 , ,

[0010] , , ,

[0009] , ,

[0011] , , ~ about 0.929 g / cm 3 of low density polyethylene, about 0.930 g / cm 3 ~ about 0.945 g / cm 3 of medium density polyethylene, about 0.945 g / cm 3 ~ about 0.970 g / cm 3 of high density polyethylene, about 0.916 g / cm 3 ~ about 0.929 g / cm 3 of linear low density polyethylene, about 0.860 g / cm 3 ~ about 0.912 g / cm 3 of ultra low density polyethylene, and further contains 10% by weight or less of one or more resins selected from the group consisting of.

[0009] In one embodiment, according to any of the foregoing embodiments, the packaged bundle is heated so that the heat - shrinkable raffia woven fabric reaches a temperature of 100°C to 165°C.

[0010] In one embodiment, when the packaged bundle is heated, according to any of the foregoing embodiments, the heat - shrinkable raffia woven fabric has both a free shrinkage of 5% to 90% in the warp direction and a free shrinkage of 5% to 90% in the weft direction at 130°C when measured by the ASTM D2732 test method.

[0011] Additional features and advantages of the embodiments are described in the following detailed description of the invention, some of which will be readily apparent to those skilled in the art from the description, or will be recognized by practicing the embodiments described herein, including the detailed description and the claims. It should be understood that both the foregoing and the following descriptions are intended to describe various embodiments and provide an overview or framework for understanding the nature and characteristics of the claimed subject matter.

Detailed Description of the Invention

[0012] Here, reference is made in detail to embodiments of the heat-shrinkable raffia woven fabric and methods thereof. The heat-shrinkable raffia woven fabric can be used for packaging a plurality of heavy articles. However, it should be noted that this is only an exemplary implementation of the embodiments disclosed herein. The embodiments are also applicable to other technologies that are susceptible to the same problems as described above. For example, the heat-shrinkable raffia woven fabric described herein can be used in other rugged packaging applications, such as rugged shipping bags, woven bags, or other general-purpose bags, all of which are within the scope of this embodiment.

[0013] In embodiments herein, the heat-shrinkable raffia woven fabric is formed from warp and weft tapes. The warp tape and the weft tape are woven together, whereby the warp tape runs longitudinally within the raffia woven fabric and the weft tape runs perpendicular to the warp tape. The term "tape" can be used interchangeably with the terms "filament", "yarn", or "fiber", all of which can be suitably used to form the heat-shrinkable raffia woven fabric.

[0014] <opposite The titer of each warp or weft tape can be from 300 DEN to 4,000 DEN. All individual values and sub-ranges from 300 DEN to 4,000 DEN are included and disclosed herein. For example, in some embodiments, each warp or weft tape can have a titer in the range of 300 DEN to 3,000 DEN, 400 DEN to 3,000 DEN, 400 DEN to 2,000 DEN, 500 DEN to 2,000 DEN, or 550 DEN to 1,500 DEN. As used herein, "DEN" refers to the denier, which is the linear mass density of the warp or weft tape. The denier or DEN is expressed as the weight of the warp or weft tape in grams per 9,000 meters (g / 9,000m) of the warp or weft tape.

[0015] The warp and weft tapes contain at least 70% by weight of an ethylene / α-olefin copolymer, based on the total polymer weight in the tape. All of the above individual values and subranges are included and disclosed herein. For example, in some embodiments, each warp and weft tape may contain 70% to 100%, 80% to 100%, 85% to 100%, 90 to 100%, 90 to 99%, 90 to 97.5%, or 90 to 95% by weight of the ethylene / α-olefin copolymer.

[0016] ethylene / α-olefin copolymer The ethylene / α-olefin copolymer contains (a) 70 to 99.5 percent, for example, 75 to 99.5 percent, | 80 to 99.5 percent, 85 to 99.5 percent, 90 to 99.5 percent, or 92 to 99.5 percent, by weight of units derived from ethylene, and (b) 0.5 to 30 percent, for example, 0.5 to 25 percent, 0.5 to 20 percent, 0.5 to 15 percent, 0.5 to 10 percent, or 0.5 to 8 percent, by weight of units derived from one or more α-olefin comonomers. The comonomer content can be measured using any suitable technique, such as techniques based on nuclear magnetic resonance (''NMR'') spectroscopy, and as described, for example, in U.S. Patent No. US7,498,282, which is incorporated herein by reference. 13 and can be measured by 13C NMR analysis.

[0017] The α-olefin comonomer has 20 or fewer carbon atoms. For example, the α-olefin comonomer can have 3 to 10 carbon atoms, or 3 to 8 carbon atoms. Exemplary α-olefin comonomers include, but are not limited to, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, and 4-methyl-1-pentene. The one or more α-olefin comonomers can be selected, for example, from the group consisting of propylene, 1-butene, 1-hexene, and 1-octene, or alternatively from the group consisting of 1-hexene and 1-octene.

[0018] In the embodiments described herein, the ethylene / α-olefin copolymer has a density of 0.945 g / cc or greater. All individual values ​​and subranges of 0.945 g / cc or greater are included and disclosed herein. For example, in some embodiments, the ethylene / α-olefin copolymer has a density ranging from a lower limit of 0.945 or 0.948 g / cc to an upper limit of 0.965, 0.960, 0.958, 0.955, or 0.953 g / cc. In other embodiments, the ethylene / α-olefin copolymer has a density ranging from 0.945 to 0.965 g / cc, 0.945 to 0.960 g / cc, 0.945 to 0.958 g / cc, 0.948 to 0.958 g / cc, or 0.948 to 0.953 g / cc.

[0019] In addition to density, ethylene / α-olefin copolymers have a melt index (I2) of 0.01 to 2 g / 10 min, as determined according to ASTM D1238 (190°C, 2.16 kg). All individual values ​​and partial ranges of 0.01 to 2 g / 10 min are included and disclosed herein. For example, in some embodiments, ethylene / α-olefin copolymers have a melt index (I2) in the range of a lower limit of 0.01, 0.05, 0.1, 0.2, 0.5, or 0.7 g / 10 min to an upper limit of 1.1, 1.5, or 1.8 g / 10 min. In other embodiments, the ethylene / α-olefin copolymer has a melt index (I2) of 0.1–1.5 g / 10 min, 0.5–1.5 g / 10 min, 0.5–1.1 g / 10 min, or 0.7–1.1 g / 10 min, as determined according to ASTM D1238 (190°C, 2.16 kg).

[0020] In addition to density and melt index (I2), ethylene / α-olefin copolymers may have melt index ratios, I10 / I2, ranging from 7.1 to 30.0. All individual values ​​and subranges of 7.1 to 30.0 are included and disclosed herein. For example, ethylene / α-olefin copolymers may have melt index ratios, I10 / I2, ranging from 7.1 to 10, 7.1 to 9.0, or 7.1 to 7.9. I10 is determined according to ASTM D1238 (190°C, 10.0 kg).

[0021] In addition to density, melt index (I2), and melt index ratio (I10 / I2), ethylene / α-olefin copolymers may have a Vicat softening temperature of 100°C to 140°C. All individual values ​​and partial ranges of 100°C to 140°C are included and disclosed herein. For example, ethylene / α-olefin copolymers may have a Vicat softening temperature of 100°C to 130°C, 110°C to 130°C, 115°C to 125°C, or 118°C to 122°C. The Vicat softening temperature may be determined according to ASTM D1525.

[0022] In addition to density, melt index (I2), melt index ratio (I10 / I2), and Vicat softening temperature, ethylene / α-olefin copolymers may have a molecular weight distribution (Mw / Mn) of 3.0–6.0, where Mw is the weight-average molecular weight (Mw) and Mn is the number-average molecular weight. All individual values ​​and subranges of 3.0–6.0 are included and disclosed herein. For example, ethylene / α-olefin copolymers may have molecular weight distributions (Mw / Mn) of 3.2–5.5, 3.5–5.5, 3.5–5.0, 4.0–5.0, or 4.2–4.6. Molecular weight can be measured using conventional gel permeation chromatography (GPC).

[0023] Any conventional ethylene (co)polymerization reaction process can be used to produce ethylene / α-olefin copolymers. Such conventional ethylene (co)polymerization reaction processes include, but are not limited to, gas-phase polymerization processes, slurry-phase polymerization processes, solution-phase polymerization processes, and combinations thereof, using one or more conventional reactors, e.g., fluidized-bed gas-phase reactors, loop reactors, stirred-tank reactors, and batch reactors in parallel, series, and / or any combination thereof. Examples of suitable polymerization processes are described in U.S. Patent Nos. 6,982,311, 6,486,284, 8,829,115, or 8,327,931, which are incorporated herein by reference.

[0024] In the embodiments described herein, the warp and weft tapes may further contain up to 30% by weight, or up to 20% by weight, or up to 10% by weight of optional polymers. Examples of optional polymers include low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, or ultra-low-density polyethylene. In some embodiments, the warp and weft tapes may further contain about 0.916 g / cm². 3 ~Approx. 0.929g / cm 3 Low-density polyethylene with a density of approximately 0.930 g / cm³ 3 ~Approx. 0.945g / cm 3 Medium-density polyethylene with a density of approximately 0.945 g / cm³ 3 ~Approx. 0.970g / cm 3 High-density polyethylene with a density of approximately 0.916 g / cm³ 3 ~Approx. 0.929g / cm 3 Linear low-density polyethylene having a density of approximately 0.860 g / cm³ 3 ~Approx. 0.912g / cm 3 It may contain up to 30 grams of one or more resins selected from the group consisting of ultra-low density polyethylene having a density of .

[0025] In the embodiments described herein, the warp and weft tapes may further contain optional additives. Exemplary additives may include, but are not limited to, antistatic agents, color enhancers, dyes, lubricants, fillers such as TiO2 or CaCO3, opacifiers, nucleating agents, processing aids, pigments, primary antioxidants, secondary antioxidants, processing aids, UV stabilizers, antiblocking agents, slip agents, tackifiers, flame retardants, antimicrobial agents, odor reducers, antifungal agents, and combinations thereof. The warp and weft tapes may contain such additives in a total weight of up to 30% by weight, or up to 20% by weight, or up to 10% by weight, based on the total weight of the materials present in the warp and weft tapes.

[0026] coating A heat-shrinkable raffia fabric according to any embodiment described herein may be further coated with a polyolefin resin. In the embodiments herein, the heat-shrinkable raffia fabric is coated with 100% by weight of polyolefin resin based on the total weight of polymers present in the coating. The polyolefin resin comprises low-density polyethylene, linear low-density polyethylene, polypropylene, or a blend of two or more of low-density polyethylene, linear low-density polyethylene, or polypropylene. In some embodiments, the polyolefin resin comprises low-density polyethylene, and the heat-shrinkable raffia fabric is coated with 100% by weight of low-density polyethylene based on the total weight of polymers present in the coating.

[0027] Examples of additives that may be present in the coating include, but are not limited to, antistatic agents, color enhancers, dyes, lubricants, fillers such as TiO2 or CaCO3, opacifiers, nucleating agents, processing aids, pigments, primary antioxidants, secondary antioxidants, processing aids, UV stabilizers, antiblocking agents, slip agents, tackifiers, flame retardants, antimicrobial agents, odor reducers, antifungal agents, and combinations thereof. The coating may contain, based on the total weight of the materials present in the coating, about 0.1 to about 30% by weight, or about 0.1 to about 20% by weight, or about 0.1 to about 10% by weight in total weight of such additives.

[0028] method Embodiments of this specification disclose a method for shrink-wrapping two or more articles. This method includes providing a heat-shrinkable raffia fabric according to any embodiment described herein, wrapping two or more articles with the heat-shrinkable raffia fabric to form a wrapped bundle, and heating the wrapped bundle to form a shrink-wrapped bundle. In some embodiments, the wrapped bundle is heated so that the heat-shrinkable raffia fabric reaches a temperature of 100°C to 165°C.

[0029] When the packaged bundle is heated, the heat-shrinkable raffia fabric may have a warp-direction free shrinkage of 5% to 90% and a weft-direction free shrinkage of 5% to 90% at 130°C, both measured by the ASTM D2732 test method. In some embodiments, the heat-shrinkable raffia fabric may have a warp-direction free shrinkage of 10% to 80% and a weft-direction free shrinkage of 10% to 80% at 130°C, both measured by the ASTM D2732 test method. Free shrinkage can be varied independently in the warp direction relative to the weft direction by changing the stretch ratio during the tape orientation step. For example, in some embodiments, the heat-shrinkable raffia fabric may have a warp-direction free shrinkage of 60% to 90% and a weft-direction free shrinkage of 5% to 25% at 130°C, both measured by the ASTM D2732 test method.

[0030] The heat-shrinkable raffia fabrics described herein can be manufactured by any suitable raffia manufacturing process. In one exemplary embodiment, the raffia process includes the following main steps involved in the production of the tape: extrusion of the film, quenching of the film, slitting of the film into the tape, orientation of the tape, annealing of the tape, winding, weaving, and finishing.

[0031] Test method Unless otherwise specified, the following test methods will be used.

[0032] density The density can be measured according to ASTM D-792.

[0033] Melt Index The melt index (I2) can be measured according to ASTM D-1238, procedure B (conditions 190°C / 2.16 kg). 10 ) can be measured according to ASTM D-1238, Procedure B (conditions 190°C / 10.0 kg).

[0034] Vicat softening point The Vicat softening point can be measured according to ASTM D-1525.

[0035] Gel permeation chromatography (GPC) The chromatography system consisted of a PolymerChar GPC-IR (Valencia, Spain) high-temperature GPC chromatograph equipped with an internal IR5 detector. The autosampler oven compartment was set to 160°C, and the column compartment to 150°C. The columns used were three Agilent "Mixed B" 30 cm 10 micron linear mixed-bed columns and a 10 μm pre-column. The chromatography solvent used was 1,2,4-trichlorobenzene containing 200 ppm butylated hydroxytoluene (BHT). The solvent source was injected with nitrogen. The injection volume used was 200 microliters, and the flow rate was 1.0 ml / min.

[0036] Calibration of the GPC column set was performed using 21 polystyrene standards with narrow molecular weight distributions ranging from 580 to 8,400,000, arranged in six "cocktail" mixtures with at least one-order-of-magnitude intervals between individual molecular weights. The standards were purchased from Agilent Technologies. Polystyrene standards were prepared at 0.025 grams in 50 ml of solvent for molecular weights greater than 1,000,000, and at 0.05 grams in 50 ml of solvent for molecular weights less than 1,000,000. The polystyrene standards were dissolved at 80 degrees Celsius for 30 minutes with gentle stirring. The peak molecular weights of the polystyrene standards were converted to polyethylene molecular weights using Formula 1 (as described in Williams and Ward, J. Sci., Polym. Let., 6, 621 (1968)): M ポリエチレン =A × (M ポリスチレン ) B (Formula 1) In the formula, M is the molecular weight, A has a value of 0.4315, and B is equal to 1.0.

[0037] A fifth-order polynomial was used to fit the equivalent calibration points for each polyethylene. A slight adjustment (approximately 0.415 to 0.44) was made to A to compensate for column resolution and band broadening effects so that the NIST standard NBS1475 could be obtained at 52,000 g / mol(Mw).

[0038] The total plate count of the GPC column set was performed using eicosane (prepared at 0.04 g in 50 ml of TCB and dissolved for 20 minutes with gentle agitation). Plate count (Equation 2) and symmetry (Equation 3) were measured in 200 microliter injections according to the following formulas:

number

number

[0039] The sample was prepared semi-automatically using PolymerChar "Instrument Control" software: A target weight of 2 mg / ml was used for the sample, and the solvent (containing 200 ppm BHT) was added to a pre-spurged nitrogen-filled vial with a septum cap via a PolymerChar high-temperature autosampler. The sample was dissolved at 160 degrees Celsius for 2 hours with "low-speed" shaking.

[0040] The calculations of Mn, Mw, and Mz were based on GPC results using the PolymerChar GPCOne® software, obtained from the IR chromatogram with the baseline subtracted at each equally spaced data retrieval point (i), and the polyethylene equivalent molecular weight derived from the narrow standard calibration curve of point (i) from Equation 1, using the internal IR5 detector (measurement channel) of the PolymerChar GPC-IR chromatograph according to Equations 4-6.

number

number

number

[0041] To monitor deviations over time, a flow rate marker (decane) was introduced into each sample via a micropump controlled by the PolymerChar GPC-IR system. This flow rate marker was used to linearly calibrate the flow rate of each sample by aligning each decane peak in the sample with the decane peak within a narrow standard calibration. Thus, any change in the decane marker peak over time is presumed to be related to a linear shift in both the flow rate and the chromatographic gradient. To facilitate the highest accuracy of RV measurement of the flow rate marker peak, a least-squares fitting routine was used to fit the peaks of the flow rate marker concentration chromatogram to a quadratic equation. The first derivative of the quadratic equation was then used to determine the true peak position. After calibrating the system based on the flow rate marker peak, the effective flow rate (as a measurement of the calibration slope) was calculated as shown in Equation 7. Processing of the flow rate marker peak was performed using PolymerChar GPCOne® software.

number

[0042] Free contraction A 100mm x 100mm specimen is immersed in oil at the temperature outlined in Table 5 for 10 seconds. Next, the specimen is removed and quickly immersed in a fluid bath under ambient conditions (23°C, 1 atm, 50% relative humidity) for 5 seconds to cool. Free shrinkage is measured in both the warp and weft directions of the specimen according to ASTM D-2732.

[0043] Impact of falling spear The impact of a dropped spear is measured according to ASTM D1709, Method A, using a stainless steel spear with a diameter of 38.1 mm, dropped from a height of 0.66 m (26 inches), and using a sample measuring 41 cm (16 inches) wide, 41 cm (16 inches) deep, and 120 cm (47 inches) high. Measurements are taken (1) under ambient conditions (23°C, 1 atm, 50% relative humidity) and (2) in a controlled environment at 93% relative humidity, 23°C, and 1 atm for two weeks. The maximum amount obtainable using Method A is 900 grams. If the sample does not fail, amounts exceeding 900 grams can be achieved.

[0044] The impact of the falling spear is also measured according to ASTM D1709, Method B, using a stainless steel spear with a diameter of 50.8 mm, at a drop height of 1.524 m (60 inches), using a sample measuring 41 cm (16 inches) wide, 41 cm (16 inches) deep, and 206 cm (81 inches) high. Measurements are taken (1) under ambient conditions (23°C, 1 atm, 50% relative humidity) and (2) in a controlled environment at 93% relative humidity, 23°C, and 1 atm for two weeks.

[0045] Elmendorf tear Elmendorf tear is measured in the warp and weft directions according to ASTM D1922. Measurements are taken (1) under ambient conditions (23°C, 1 atm, 50% relative humidity), (2) in a controlled environment at 93% relative humidity, 23°C, and 1 atm for 48 hours, and (3) in a controlled environment at 93% relative humidity, 23°C, and 1 atm for 2 weeks. [Examples]

[0046] The resins used in the examples are shown in Table 1 below. All resins are commercially available from The Dow Chemical Company (Midland, Michigan).

[0047] [Table 1]

[0048] Example 1 of the Invention ("Invention 1") - The tape was manufactured from 100% by weight of DOWLEX® 2050B having 820 denier and a width of 3.0 mm. The tape was manufactured using a Starlinger Starex 1500ES tape extrusion line under the process conditions shown in Table 2.

[0049] [Table 2]

[0050] Using the tape, raffia cloth was produced using a Starlinger Alpha 6 (6-shuttle circular loom). The width of the raffia cloth was 53.34 cm (60 gsm). Next, the raffia cloth was coated with 100 wt% LDPE722 by an extrusion coating process using a Starlinger Staco Tec line under the following process conditions.

[0051] [Table 3]

[0052] The coated heat-shrinkable raffia fabric had a 20 gsm coating on both sides, and the heat-shrinkable raffia fabric weighed 60 gsm. The total weight of the coated heat-shrinkable raffia fabric was 100 gsm.

[0053] Comparative film A ("Comparative A"): A single-layer film was produced on Dr. Colin's inflation film line. This film contains 50 wt% LDPE 132i, 30 wt% DOWLEX® 2045.11, and 20 wt% DOWLEX® 2050B. The inflation film line parameters are shown in Table 4.

[0054] [Table 4]

[0055] Comparative corrugated cardboard: As outlined in Table 5, this refers to microflute corrugated cardboard of various weights, typically used for unitization applications and for comparative purposes.

[0056] The characteristics were measured and are shown in Table 5 below. "NM" means not measured.

[0057] [Table 5]

[0058] The results show that the film of the present invention (Invention 1) has improved free shrinkage compared to the comparative film. Furthermore, the film of the present invention exhibits improved impact resistance and tearing properties compared to the comparative film and comparative corrugated cardboard. The present invention includes the following embodiments. Section 1. A method for shrink-wrapping two or more articles, To provide a heat-shrinkable raffia woven fabric formed from warp and weft tapes, wherein the warp and weft tapes contain at least 70% by weight of an ethylene / alpha-olefin copolymer having a density of 0.945 g / cc or more and a melt index (I2) of 0.01 to 2.0 g / 10 min determined according to ASTM D1238 (190°C, 2.16 kg), based on the total weight percentage of the polymer present in the warp and weft tapes. The process involves wrapping two or more articles in the aforementioned heat-shrinkable raffia fabric to form a wrapped bundle, A method comprising heating the aforementioned packaged bundle to form a shrink-packaged bundle. Section 2. The method according to claim 1, wherein the heat-shrinkable raffia fabric is coated with a polyolefin resin to form a coated heat-shrinkable raffia fabric. Section 3. The method according to claim 2, wherein the polyolefin resin comprises low-density polyethylene, linear low-density polyethylene, polypropylene, or a blend of two or more of low-density polyethylene, linear low-density polyethylene, or polypropylene. Section 4. The method according to item 2 or 3, wherein the polyolefin resin comprises low-density polyethylene. Section 5. The method according to any one of claims 1 to 4, wherein the ethylene / alpha-olefin copolymer has a density of 0.945 to 0.960 g / cc. Section 6. The method according to any one of claims 1 to 5, wherein the ethylene / alpha-olefin copolymer has a melt index (I2) of 0.1 to 1.5 g / 10 min as determined according to ASTM D1238 (190°C, 2.16 kg). Section 7. The method according to any one of claims 1 to 6, wherein the ethylene / alpha-olefin copolymer has a melt index ratio (I10 / 12) of 7.1 to 30.0, and I10 is determined according to ASTM D1238 (190°C, 10.0 kg). Section 8. The method according to any one of claims 1 to 7, wherein the ethylene / alpha-olefin copolymer has a Vicat softening temperature of 100°C to 140°C. Section 9. The method according to any one of claims 1 to 8, wherein the ethylene / alpha-olefin copolymer has a molecular weight distribution (Mw / Mn) of 3.0 to 6.0, where Mw is the weight-average molecular weight and Mn is the number-average molecular weight. Section 10. The method according to any one of claims 1 to 9, wherein the packaged bundle is heated so that the heat-shrinkable raffia fabric reaches a temperature of 100°C to 165°C. Section 11. The method according to any one of claims 1 to 10, wherein when the packaged bundle is heated, the heat-shrinkable raffia fabric has a warp-direction free shrinkage of 5% to 90% at 130°C and a weft-direction free shrinkage of 5% to 90% at 130°C, both as measured by the ASTM D2732 test method. Section 12. The aforementioned warp and weft tapes are further approximately 0.916 g / cm 3 ~Approx. 0.929g / cm 3 Low-density polyethylene with a density of approximately 0.930 g / cm³ 3 ~Approx. 0.945g / cm 3 Medium-density polyethylene with a density of approximately 0.945 g / cm³ 3 ~Approx. 0.970g / cm 3 High-density polyethylene with a density of approximately 0.916 g / cm³ 3 ~Approx. 0.929g / cm 3 Linear low-density polyethylene having a density of approximately 0.860 g / cm³ 3 ~Approx. 0.912g / cm 3 The method according to claim 11, comprising 30% by weight or less of one or more resins selected from the group consisting of ultra-low density polyethylene having a density of , based on the total weight percentage of polymers present in the warp and weft tapes.

Claims

1. A method for shrink-wrapping two or more articles, To provide a heat-shrinkable raffia woven fabric formed from warp and weft tapes, wherein each of the warp and weft tapes contains 80 to 100% by weight of an ethylene / alpha-olefin copolymer having a density of 0.945 g / cc or more, a melt index (I2) of 0.01 to 2.0 g / 10 min determined according to ASTM D1238 (190°C, 2.16 kg), and a melt index ratio (I10 / I2) of 7.1 to 10 determined according to ASTM D1238 (190°C, 10.0 kg), based on the total weight percentage of the polymer present in the warp and weft tapes. The heat-shrinkable raffia fabric is coated with a polyolefin resin to form a coated heat-shrinkable raffia fabric. To wrap two or more articles in the coated heat-shrinkable raffia fabric to form a wrapped bundle, A method comprising heating the aforementioned packaged bundle to form a shrink-packaged bundle.

2. The method according to claim 1, wherein the polyolefin resin comprises low-density polyethylene, linear low-density polyethylene, polypropylene, or a blend of two or more of low-density polyethylene, linear low-density polyethylene, or polypropylene.

3. The method according to claim 1, wherein the polyolefin resin comprises low-density polyethylene.

4. The method according to any one of claims 1 to 3, wherein the ethylene / alpha-olefin copolymer has a density of 0.945 to 0.960 g / cc.

5. The method according to any one of claims 1 to 4, wherein the ethylene / alpha-olefin copolymer has a melt index (I2) of 0.1 to 1.5 g / 10 min as determined according to ASTM D1238 (190°C, 2.16 kg).

6. The method according to any one of claims 1 to 5, wherein the ethylene / alpha-olefin copolymer has a Vicat softening temperature of 100°C to 140°C, and the Vicat softening temperature is determined according to ASTM D1525.

7. The method according to any one of claims 1 to 6, wherein the ethylene / alpha-olefin copolymer has a molecular weight distribution (Mw / Mn) of 3.0 to 6.0, where Mw is the weight-average molecular weight and Mn is the number-average molecular weight.

8. The method according to any one of claims 1 to 7, wherein the packaged bundle is heated so that the coated heat-shrinkable raffia fabric reaches a temperature of 100°C to 165°C.

9. The method according to any one of claims 1 to 8, wherein when the packaged bundle is heated, the coated heat-shrinkable raffia fabric has a warp-direction free shrinkage of 5% to 90% at 130°C and a weft-direction free shrinkage of 5% to 90% at 130°C, both as measured by the ASTM D2732 test method.

10. The longitudinal and transverse yarn tapes further have a low-density polyethylene having a density of about 0.916 g / cm ３ , ３ , ３ , ３ , ３ to about 0.929 g / cm ３ , a medium-density polyethylene having a density of about 0.930 g / cm ３ to about 0.945 g / cm ３ , a high-density polyethylene having a density of about 0.945 g / cm ３ to about 0.970 g / cm ３ , a linear low-density polyethylene having a density of about 0.916 g / cm ３ to about 0.929 g / cm ３ , and an ultra-low density polyethylene having a density of about 0.860 g / cm ３ to about 0.912 g / cm ３ The method according to claim 9, comprising 20% by weight or less, based on the total weight% of the polymer present in the longitudinal and transverse yarn tapes, of one or more resins selected from the group consisting of.

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