Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
  • B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
  • B29C55/10—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial
  • B29C55/12—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial biaxial
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
  • B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
  • B29C55/10—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial
  • B29C55/12—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial biaxial
  • B29C55/14—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial biaxial successively
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
  • B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
  • B29C55/10—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial
  • B29C55/12—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial biaxial
  • B29C55/16—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial biaxial simultaneously

Definitions

• the present invention relates to films, laminates and packaging materials.
• HDPE high-density polyethylene
• Cited document 3 discloses an invention relating to a stretched film made of a polyethylene resin composition with specific physical properties that can be used as a base material for packaging materials with an excellent balance of rigidity, low shrinkage, and longitudinal tear strength.
• a barrier layer may be formed on the surface of the packaging material by deposition or coating.
• the barrier layer may become contaminated by low molecular weight components of polyethylene, which can result in a decrease in adhesive strength when the packaging material is subsequently dry laminated with other substrates. Cited documents 1 to 3 do not describe or suggest any means of solving this problem.
• the objective of the present invention is to provide a film that can be used as a base material for packaging materials with excellent low-pollution properties.
• a laminate comprising the film according to any one of items [1] to [3].
• a package comprising the film according to any one of items [1] to [3].
• a package comprising the laminate according to item [4] or [5].
• the film of the present invention has excellent low-pollution properties and can be suitably used as a recyclable packaging material, and further has excellent elasticity (rigidity) and transparency.
• the film according to the present invention contains an ethylene-based polymer satisfying the following requirements (a1) to (a4).
• (a1) The density is 940 to 980 kg/ m3 .
• (a2) The melt flow rate (MFR) measured at 190° C. under a load of 2.16 kg is 0.01 to 10 g/10 min.
• (a3) The content of low molecular weight components is 300 ppm or less.
• (a4) The ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (molecular weight distribution: Mw/Mn) measured by gel permeation chromatography (GPC) is 10 or less.
• the lower limit of the density of the ethylene-based polymer is usually 940 kg/m 3 or more, preferably 942 kg/m 3 or more, more preferably 944 kg/m 3 or more, even more preferably 946 kg/m 3 or more, even more preferably 948 kg/m 3 or more, and particularly preferably 950 kg/m 3 or more, and the upper limit is usually 980 kg/m 3 or less, preferably 975 kg/m 3 or less, more preferably 970 kg/m 3 or less, and even more preferably 965 kg/m 3 or less.
• the density is determined in accordance with JIS This value is measured in accordance with K7112 (density gradient tube method).
• the lower limit of the MFR of the ethylene polymer is usually 0.01 g/10 min or more, preferably 0.05 g/10 min or more, more preferably 0.1 g/10 min or more, further preferably 0.3 g/10 min or more, further more preferably 0.5 g/10 min or more, particularly preferably 0.7 g/10 min or more, and the upper limit is usually 10 g/10 min or less, preferably 8 g/10 min or less, more preferably 5 g/10 min or less.
• the upper limit of the low molecular weight component of the ethylene-based polymer is usually 300 ppm or less, preferably 250 ppm or less, more preferably 200 ppm or less, further preferably 150 ppm or less, particularly preferably 100 ppm or less, and the lower limit is not particularly limited, but is preferably 1 ppm or more, more preferably 5 ppm or more.
• the low molecular weight component of the ethylene-based polymer is within the above range, a film having excellent low contamination properties can be obtained.
• the content of low molecular weight components in the present invention is the value of the amount of C10 to C50 components, which is determined by quantitatively measuring (in terms of n- C20H42 ) the absolute calibration curve method using an appropriate volume of Soxhlet extraction solution ( hexane ) as a test solution and subjecting the test solution to GC (FID). Details of Soxhlet extraction and calibration curve preparation are described below.
• Soxhlet Extraction The Soxhlet extraction conditions are as follows: 5 g of sample is subjected to Soxhlet extraction with a solvent, and the solution is adjusted to a constant volume of 25 mL to 100 mL to prepare a test liquid. (2) Preparation of a calibration curve based on n- C20H42 conversion The quantitative determination of C10 to C50 oligomers based on C20 conversion is carried out by subjecting four standard solutions of different concentrations to GC (FID ) using n- C20H42 as the standard, and preparing a calibration curve by the absolute calibration curve method using the obtained area values and concentrations, and determining the slope and intercept of the calibration curve.
• FID GC
• the upper limit of Mw/Mn of the ethylene polymer is usually 10 or less, preferably 8 or less, more preferably 7 or less, even more preferably 6 or less, still more preferably 5 or less, and particularly preferably 4.5 or less, and the lower limit is not particularly limited, but is preferably 1.0 or more, more preferably 1.5 or more, even more preferably 2.0 or more, still more preferably 2.2 or more, and particularly preferably 2.4 or more.
• the Mw/Mn of the ethylene polymer is within the above range, the ethylene polymer contains few low molecular weight components, is less sticky and has good stain resistance, and has good extrudability and mechanical properties such as dart impact strength.
• the ethylene polymer is not particularly limited as long as it satisfies the above requirements (a1) to (a4), but ethylene homopolymers and copolymers of ethylene and ⁇ -olefins having 3 or more carbon atoms (ethylene- ⁇ -olefin copolymers) are preferred.
• ethylene- ⁇ -olefin copolymers include propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, and 1-octene.
• the ethylene-based polymer contains ethylene-derived structural units in an amount of 50 mol% or more and 100 mol% or less, preferably more than 50 mol% and 100 mol% or less, more preferably 55 to 100 mol%, and even more preferably 60 to 100 mol%.
• the ethylene polymer may contain one or more constituent units derived from biomass-derived monomers (ethylene, ⁇ -olefin).
• the monomers constituting the polymer may be only biomass-derived monomers, or may be both biomass-derived monomers and fossil fuel-derived monomers.
• the biomass-derived monomer is a monomer obtained from any renewable natural raw material, such as a plant-derived or animal-derived monomer, including fungi, yeast, algae, and bacteria, and its residue, and contains about 1 ⁇ 10 ⁇ 12 of 14 C isotope as carbon, and has a biomass carbon concentration (pMC) of about 100 (pMC) measured in accordance with ASTM D6866.
• the biomass-derived monomer (ethylene) can be obtained, for example, by a conventionally known method.
• the ethylene polymer contains a structural unit derived from a biomass-derived monomer from the viewpoint of reducing the environmental load (mainly reducing greenhouse gases). If the polymer production conditions, such as the polymerization catalyst, polymerization process, and polymerization temperature, are the same, even if the raw material monomer contains a biomass-derived olefin, the molecular structure, except for the inclusion of 14C isotopes in a ratio of about 10-12 to 10-14 , is the same as that of an ethylene polymer made of a fossil fuel-derived monomer. Therefore, the performance of these is also considered to be unchanged.
• the ethylene-based polymer may contain chemically recycled monomers (ethylene, ⁇ -olefins).
• the monomers constituting the polymer may be only chemically recycled monomers, or may contain chemically recycled monomers and fossil fuel-derived monomers and/or biomass-derived monomers. Chemically recycled monomers can be obtained by conventionally known methods.
• chemically recycled monomers are monomers obtained by depolymerizing or pyrolyzing polymers such as waste plastics back into monomer units such as ethylene, as well as monomers produced using such monomers as raw materials. Therefore, if the polymer production conditions, such as the polymerization catalyst, polymerization process, and polymerization temperature, are the same, the molecular structure is the same as that of an ethylene-based polymer made from a monomer derived from fossil fuels. Therefore, their performance is said to be unchanged.
• the ethylene polymer can be produced by the high-temperature solution method using a known catalyst such as a Ziegler-Natta catalyst or a metallocene catalyst.
• the catalyst is not particularly limited, but considering the balance with extrudability, a Ziegler-Natta catalyst is preferable because it can produce an ethylene polymer with a moderate molecular weight distribution.
• the high-temperature solution method is a method in which hexane or the like is used as a solvent and pressurized at high temperatures to produce a polymer in a homogeneous state.
• the reaction is carried out in a homogeneous phase, so the composition distribution of the obtained ethylene polymer is small, and as a result, the production of oligomers and other volatile compounds can be suppressed.
• the solvent such as hexane is removed by flashing under atmospheric pressure, and the precipitated polymer is dried separately. Even during flashing, oligomers and volatile compounds are removed along with the solvent.
• the film of ethylene polymer (A) obtained by the high-temperature solution method is characterized by an extremely small amount of components seeping out of the film, and also has excellent dart impact strength.
• the film of the present invention is characterized by containing the above-mentioned ethylene polymer.
• the film of the present invention may contain at least one of various additives added to general polyolefin films, such as weathering stabilizers, heat stabilizers, antistatic agents, antifogging agents, antiblocking agents, slipping agents, lubricants, pigments, dripping agents, and nucleating agents, as necessary, so long as the object of the present invention is not impaired.
• the film of the present invention can be produced by molding the raw material resin containing the above-mentioned ethylene-based polymer by a known method including a step of melting the raw material resin.
• the film of the present invention is a non-stretched film or a stretched film. In consideration of mechanical strength, etc., a stretched film is preferred.
• the thickness of the film of the present invention may be set appropriately depending on various applications, but in general, the lower limit is preferably 0.005 mm (5 ⁇ m) or more, more preferably 0.01 mm (10 ⁇ m) or more, and the upper limit is preferably 1 mm or less, more preferably 0.5 mm or less, and even more preferably 0.3 mm or less.
• the thickness of the film within the above range, a balance between rigidity and strength as a packaging material can be achieved.
• the film of the present invention is a stretched film, it is a uniaxially stretched film or a biaxially stretched film.
• the stretched film may be a single layer film or a multilayer film.
• the above-mentioned ethylene-based polymer may be used in any layer or in a plurality of layers.
• the layer structure of the multilayer film is not particularly limited, but examples thereof include the following structures.
• the ethylene-based polymer/linear low-density polyethylene or medium-density polyethylene/the ethylene-based polymer The ethylene polymer/linear low-density polyethylene or medium-density polyethylene/medium-density polyethylene, the above-mentioned ethylene-based polymer/high density polyethylene/linear low-density polyethylene or medium-density polyethylene/high-density polyethylene/the above-mentioned ethylene-based polymer, The ethylene polymer/high density polyethylene/linear low density polyethylene or medium density polyethylene/high density polyethylene/linear low density polyethylene or medium density polyethylene, The ethylene polymer/linear low-density polyethylene or medium-density polyethylene/linear low-density polyethylene or medium-density polyethylene/linear low-density polyethylene or medium-density polyethylene, high density polyethylene/linear low density polyethylene/linear low density polyethylene, high density polyethylene/linear low density poly
• the stretching ratio of the stretched film is preferably 1.5 times or more, more preferably 2.0 times or more, particularly preferably 2.5 times or more, and most preferably 3.0 times or more. There is no particular upper limit to the stretching ratio, but it is preferably 60 times or less, more preferably 50 times or less. By having the stretching ratio within the above range, rigidity and strength can be obtained.
• the method for producing the stretched film is not particularly limited, but examples include a method in which a film (raw material) obtained by a known melt extrusion molding method is stretched.
• Methods for stretching the raw material include simultaneous or sequential biaxial stretching in the lengthwise and widthwise directions using the tenter method, simultaneous biaxial stretching in the lengthwise and widthwise directions using the tubular method, and uniaxial stretching in the film flow direction using a difference in the rotation speed ratio of two or more rolls.
• uniaxial stretching it is preferable to unwind the raw material into a roll stretching machine, preheat it with a preheating roll, and then uniaxially stretch it in the MD direction (take-up speed direction). From the viewpoint of increasing manufacturing efficiency, it is preferable to preheat the raw material and then immediately uniaxially stretch it in the MD direction.
• uniaxial stretching means stretching in a uniaxial direction, but it may be stretched in a direction different from the uniaxial direction to the extent that the effect of the present invention is not impaired. This is because, depending on the stretching equipment used, even if an attempt is made to stretch in a uniaxial direction, it may actually be stretched in a direction different from the uniaxial direction.
• the stretched film may be annealed after stretching.
• the annealing can be carried out by contacting the stretched sheet with a heated roll.
• the stretched film has high transparency, and the haze measured under the conditions employed in the examples described below is preferably 20% or less, and more preferably 15% or less.
• the laminate of the present invention is characterized by including the above-mentioned film of the present invention.
• the laminate of the present invention may have a plurality of layers made of the film of the present invention.
• the above-mentioned film of the present invention is preferably used as a substrate in the laminate.
• the other layers in the laminate of the present invention can be appropriately adopted depending on the application, and examples thereof include a barrier layer.
• the laminate of the present invention can be produced by known methods, such as co-extrusion molding of one or more thermoplastic resins, extrusion lamination, dry lamination, thermal lamination, etc.
• the barrier layer can be formed on the surface of the film of the present invention by a known metal deposition, coating method, or coextrusion method.
• the film of the present invention can be further provided with various functions by laminating.
• lamination methods include co-extrusion with a barrier resin (e.g., EVOH, Ny, etc.) or an adhesive resin (e.g., Admer, etc.), and coating the surface (e.g., a vapor deposition film, etc.).
• a barrier resin e.g., EVOH, Ny, etc.
• an adhesive resin e.g., Admer, etc.
• coating the surface e.g., a vapor deposition film, etc.
• the vapor deposition film may be made of a metal or an inorganic oxide.
• Metals that make up the metal vapor deposition film include, for example, aluminum, chromium, tin, nickel, copper, silver, gold, and platinum.
• Metal oxides include aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, and barium oxide.
• the packaging material of the present invention is characterized by including the above-mentioned film of the present invention.
• the packaging material can be obtained by forming the above-mentioned laminate of the present invention into a bag-shaped container, filling it with a packaged item (content) for various uses, and heat sealing the bag-shaped container.
• MFR density, molecular weight distribution (Mw/Mn), amount of low molecular weight components, elastic modulus, haze and low staining properties were measured or evaluated as follows.
• MFR Melt flow rate
• Mw/Mn ⁇ Molecular weight distribution (Mw/Mn)>
• Mw weight average molecular weight
• Mn number average molecular weight
• Mw/Mn molecular weight distribution
• the amount of low molecular weight components in the ethylene polymers used in the Examples and Comparative Examples was determined as follows: A suitable volume of Soxhlet extract (hexane) was used as a test liquid, and the test liquid was subjected to GC (FID), and the amount of C10 - C50 components quantified (converted into n- C20H42 ) by the absolute calibration curve method was determined as the amount of low molecular weight components. Details are as described above.
• the dart impact strength was measured in accordance with ASTM D1709 under the following conditions.
• the test piece was clamped by an air clamp method, a hemispherical dart was dropped from a certain height, and the load at which the test piece broke by 50% was read from the graph.
• the number of drops per level was 10.
• the dart impact strength was evaluated using a single-layer film (non-stretched film) with a thickness of 40 ⁇ m and a width of 320 mm, which was formed under the following molding conditions.
• Example 1 As an ethylene-based polymer, "Neozex 5510F” manufactured by Prime Polymer Co., Ltd., which was produced by a solution process using a Ziegler catalyst, had an MFR of 1.0 g/10 min, and a density of 957 kg/ m3, was used. The polymer was melt-kneaded at 230°C in an extruder, and then a non-stretched film (raw film) having a thickness of 125 ⁇ m was formed by a cast molding machine. This raw film was uniaxially stretched at a stretch ratio of 5 times while being heated to 120°C with a heating roll to obtain a uniaxially stretched film having a thickness of 25 ⁇ m.
• Example 2 An unstretched film was obtained in the same manner as in Example 1, except that "Neozex 5520F” manufactured by Prime Polymer Co., Ltd., which was produced by a solution process using a Ziegler catalyst and had an MFR of 2.2 g/10 min and a density of 955 kg/ m3, was used as the ethylene polymer. Measurements and evaluations were also performed in the same manner as in Example 1 (note that some measurements and evaluations were omitted). The results are shown in Table 1.
• Example 3 Measurements and evaluations were carried out in the same manner as in Example 1, except that "EVL-H SP6011" manufactured by Prime Polymer Co., Ltd., which was produced by a slurry method using a metallocene catalyst and had an MFR of 1.1 g/10 min and a density of 957 kg/ m3 , was used as the ethylene polymer (some measurements and evaluations were omitted). The results are shown in Table 1.
• Example 4 An unstretched film was obtained in the same manner as in Example 1, except that "Neozex 5521F” manufactured by Prime Polymer Co., Ltd., which was produced by a solution process using a Ziegler catalyst and had an MFR of 2.3 g/10 min and a density of 953 kg/ m3, was used as the ethylene polymer. Measurements and evaluations were also performed in the same manner as in Example 1 (note that some measurements and evaluations were omitted). The results are shown in Table 1.
• Example 5 An unstretched film was obtained in the same manner as in Example 1, except that "Neozex 5021F” manufactured by Prime Polymer Co., Ltd., which was produced by a solution process using a Ziegler catalyst and had an MFR of 2.3 g/10 min and a density of 948 kg/ m3, was used as the ethylene polymer. Measurements and evaluations were also performed in the same manner as in Example 1 (note that some measurements and evaluations were omitted). The results are shown in Table 1.
• Example 1 A non-stretched film and a stretched film were obtained in the same manner as in Example 1, except that "Hi-Zex 3600F” manufactured by Prime Polymer Co., Ltd., having an MFR of 1.0 g/10 min and a density of 958 kg/m3, was used as the ethylene polymer. Measurements and evaluations were also performed in the same manner as in Example 1. The results are shown in Table 1.
• Example 2 An unstretched film and a stretched film were obtained in the same manner as in Example 1, except that "Hi-Zex 7000F" manufactured by Prime Polymer Co., Ltd., having an MFR of 0.04 g/10 min and a density of 951 kg/m3, was used as the ethylene polymer. Measurements and evaluations were also performed in the same manner as in Example 1. The results are shown in Table 1.
• Example 3 An unstretched film was obtained in the same manner as in Example 1, except that "Evolue SP4030" manufactured by Prime Polymer Co., Ltd., having an MFR of 4 g/10 min and a density of 938 kg/ m3, was used as the ethylene polymer. Measurements and evaluations were also performed in the same manner as in the examples (note that some measurements and evaluations were omitted). The results are shown in Table 1.

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