Coated packaging film suitable for packaging

Abstract

The present invention relates to a coated packaging film comprising: (1) a heat sealable substrate having a heat sealable region and opposite surfaces on opposite sides of the heat sealable region, (2) a heat resistant coating disposed on at least a portion of the opposite surfaces of the substrate, wherein the heat resistant coating comprises (I) one or more polymers (I) having a glass transition temperature Tg1 of at least 140 DEG C, and (II) one or more polymers (II) having a glass transition temperature Tg2 of at most 50 DEG C wherein the difference between Tg1 and Tg2 is at least 100 DEG C wherein Tg1 and Tg2 are determined by differential scanning calorimetry as described in the specification, and wherein the substrate consists of at least 60% by weight, based on the total weight of the substrate, of a polymer selected from the group consisting of polyethylene (PE), oriented polyethylene, and any combination thereof.

Description

[0001] The present invention relates to packaging films, and in particular to heat-sealable packaging films. The present invention further relates to a packaging article formed by heat-sealing the packaging film to itself or to another packaging component.

[0002] Packaging films are usually formed into packaging articles, such as bags, pouches, etc. Heat sealability is therefore an important functional property of packaging films, because it enables the film to be made into pouches, bags, etc., and also to seal the contents of the package, such as food, inside. It is desirable to heat seal at high speeds and a wide operating window to achieve good economy in producing sealed packages.

[0003] A commonly used heat sealing technique is "hot jaw" (also called "heat seal jaw" or "hot bar") sealing, in which two film materials are clamped together between jaws, at least one of which is heated until the contact interface reaches its sealing temperature and forms a heat seal. It is important that while the seal is being formed, the remainder of the film does not soften or melt enough to cause production problems, such as deformation or shrinkage of the film resulting in unacceptable final packaging, or sticking or melting to the heat seal jaws so as to prevent smooth running production. A heat sealable area is an area that contains a sealable material and which is capable of forming a bond when exposed to heat and pressure for a short dwell time, a process commonly referred to as heat sealing.

[0004] It is desirable to broaden the operating window in which sealing can be performed without compromising the appearance or other performance characteristics of the packaging film. In addition, in order to accelerate the heat sealing process, the temperature of the heat-sealable area should be brought to the sealing temperature as quickly as possible, which can be facilitated by increasing the temperature of the heat sealing rod of the heat sealer. However, when the temperature of the heat sealing rod becomes too high, the packaging film may be damaged, which is of course undesirable.

[0005] In addition, the demand for recyclable packaging is increasing day by day, and in particular, it is made of a high proportion of single material types and is therefore easier to recycle into high-value new materials than multi-material packaging based on flexible film packaging. An example thereof is the flexible film packaging that most of the single polymer family (such as polyethylene (PE), polypropylene (PP) and polyethylene terephthalate (PET)) is made of. The packaging film comprising biaxially oriented polypropylene (BOPP) or biaxially oriented polyethylene terephthalate (BOPET) film is generally used for packaging, such as packaging based on flexible film. Orientation is a common method for improving the mechanical and optical properties of polymers, and is usually carried out in a uniaxial or biaxial direction, using a process such as machine oriented orientation, casting or blow molding process. This oriented film made of PE, PP and PET is widely used in the packaging industry. For PE, biaxial orientation improves the properties of PE film such as transparency, rigidity, puncture resistance, tensile strength and shrinkage. Biaxially oriented polyethylene (BOPE) film becomes more and more popular in the packaging industry, because BOPE has excellent optical properties and printability. In addition, it may be cheaper than BOPET and BOPP. However, when designing packaging films made of a high proportion of a single material type, the choice of materials available for the heat-sealable area and the rest of the film is more limited. It is therefore more difficult to design such packaging with a wide operating window for heat sealing. This is especially true when using majority PE packaging films, due to the lower thermal stability of PE compared to PP and PET. It has been surprisingly found that the heat-resistant coating used in the present invention can achieve a wider operating window for heat sealing of substrates based primarily on polyethylene, i.e., it can increase the heat sealing temperature at which visible deformation / damage occurs, while also not hindering heat seal formation.

[0006] The object of the present invention is to enhance the heat-sealing properties of packaging films comprising polyethylene-based substrates.

[0007] This object has surprisingly been achieved by providing a coated packaging film comprising:

[0008] (1) a heat-sealable substrate having a heat-sealable region and opposing surfaces on opposite sides of the heat-sealable region,

[0009] (2) a heat-resistant coating disposed on at least a portion of the opposite surface of the substrate,

[0010] The heat-resistant coating comprises:

[0011] (I) one or more having a glass transition temperature T of at least 140°C g1 The polymer (I), and

[0012] (II) one or more materials having a glass transition temperature T g2The polymer (II), the T g2 Lower than T g1 and at most 50°C,

[0013] Where T g1 and T g2 The difference between is at least 100°C,

[0014] Wherein T g1 and T g2 measured by differential scanning calorimetry as described herein, and

[0015] The substrate is composed of at least 60 wt % of a polymer selected from polyethylene (PE), oriented polyethylene and any combination thereof, based on the total weight of the substrate.

[0016] It has been surprisingly found that the coated packaging films of the present invention can broaden the operating window in which sealing can be performed without compromising the appearance or other performance characteristics of the packaging film. It has also been surprisingly found that the coated packaging films of the present invention make it possible to increase the temperature of the heat sealing bar and thereby increase the speed of the heat sealing process while protecting the substrate from damage (i.e., without causing increased deformation of the substrate coated with the packaging film) or from sticking to the heat sealing bar during the heat sealing process. Examples of deformation are shrinkage, melting (optionally resulting in sticking to the heat sealing bar) and / or wrinkling.

[0017] EP-A-675177 describes a heat-resistant coating composition, preferably containing a maleic anhydride copolymer and a (meth)acrylate (co)polymer as latex polymer, which is suitable for use as an overcoat or overprint varnish for inks on packaging materials, wherein the coating must have good heat resistance to avoid damaging the printed material, or is suitable for use in paper products such as paper plates and cups for hot foods. DE69728387T2 describes an overprint varnish for coating on paper or paperboard. These publications do not disclose the use of the coated substrate in a heat sealing process, nor do they disclose or teach that the coating can widen the operating window in which sealing can be performed at a heat-sealable area on the surface opposite to where the coating is. Polyscope's brochure " Heatboosters" describes certain styrene maleic anhydride (SMA) copolymers, compounds, aqueous solutions and styrene maleic anhydride N-phenylmaleimide terpolymers as providing heat boosting opportunities, but does not disclose or teach that these products can be used to improve heat treatment systems containing Heatbooster's coatings have heat-sealing properties on coated substrates.

[0018] A first aspect of the present invention is a coated packaging film comprising:

[0019] (1) a heat-sealable substrate having a heat-sealable region and opposing surfaces on opposite sides of the heat-sealable region,

[0020] (2) a heat-resistant coating provided on at least a portion of the opposite surface of the substrate,

[0021] The heat-resistant coating comprises:

[0022] (I) one or more having a glass transition temperature T of at least 140°C g1 The polymer (I), and

[0023] (II) one or more materials having a glass transition temperature T g2 The polymer (II), the T g2 Lower than T g1 and at most 50°C,

[0024] Where T g1 and T g2 The difference between is at least 100°C,

[0025] Wherein T g1 and T g2 measured by differential scanning calorimetry as described herein, and

[0026] The substrate is composed of at least 60 wt % of a polymer selected from polyethylene (PE), oriented polyethylene and any combination thereof, based on the total weight of the substrate.

[0027] A second aspect of the present invention is a substrate having a first surface, wherein the substrate comprises a heat-resistant coating disposed on at least a portion of the first surface, the substrate being intended for use in producing a heat-sealable packaging film having a heat-sealable area on the opposite side of the heat-resistant coating, wherein the heat-resistant coating comprises:

[0028] (I) one or more having a glass transition temperature T of at least 140°C, more preferably at least 142°C, more preferably at least 145°C, more preferably at least 145°C, preferably at least 150°C and preferably at most 260°C, more preferably at most 250°C, more preferably at most 240°C, more preferably at most 230°C, more preferably at most 220°C g1 The polymer (I), and

[0029] (II) One or more having a value lower than T g1 and a glass transition temperature T of at most 50°C g2 The polymer (II)

[0030] Where T g1 and T g2 The difference between is at least 100°C,

[0031] Wherein T g1 and T g2 Determined by differential scanning calorimetry as described herein, and

[0032] The substrate is composed of at least 60 wt % of a polymer selected from polyethylene (PE), oriented polyethylene and any combination thereof, based on the total weight of the substrate.

[0033] The third aspect of the present invention is a packaging article obtained by heat sealing the coated packaging film of the first aspect of the present invention to a heat-sealable substrate, which may be the same coated packaging film or another heat-sealable substrate, wherein the heat-resistant coating forms the outermost surface of the packaging article.

[0034] A fourth aspect of the present invention is a packaging film comprising the substrate according to the second aspect of the present invention.

[0035] The fifth aspect is a packaging product obtained by heat sealing the packaging film of the fourth aspect of the present invention to a heat-sealable substrate, which can be the same packaging film or another heat-sealable substrate, wherein the heat-resistant coating forms the outermost surface of the packaging product.

[0036] With glass transition temperature T g1 (one or more) polymers (I)

[0037] You should choose a high enough T g1 , so as to increase the temperature causing deformation of the opposite surface when the coated packaging film is subjected to heat sealing conditions.

[0038] The one or more polymers (I) have a glass transition temperature T of at least 140°C, preferably at least 142°C, more preferably at least 145°C, more preferably at least 150°C and preferably at most 260°C, more preferably at most 250°C, more preferably at most 240°C, more preferably at most 230°C, more preferably at most 220°C, as determined by DSC as described herein. g1 .

[0039] The one or more polymers have a glass transition temperature T g1The estimated thermal mass content of the polymer (I) is preferably at least 7.5% by weight, even more preferably at least 10% by weight, even more preferably at least 15% by weight, even more preferably at least 20% by weight, and the estimated thermal mass content of the one or more polymers (I) is preferably at most 85% by weight, more preferably at most 80% by weight, even more preferably at most 75% by weight, even more preferably at most 70% by weight, relative to the total mass of polymers present in the heat-resistant coating, wherein the one or more polymers having T g1 The heat estimated mass content of the polymer is determined using the method as described herein.

[0040] Preferably, the one or more polymers (I) are or are derived from a polymer comprising:

[0041] one or more monomers (A1) selected from styrene, substituted styrene, acrylate, methacrylate and itaconate, and

[0042] One or more monomers (A2) selected from acrylic acid, β-carboxyethyl acrylate, methacrylic acid, maleic acid, maleic anhydride and itaconic acid.

[0043] More preferably, the one or more monomers (A1 ) are selected from styrene and methacrylates, and the one or more monomers (A2) are selected from acrylic acid, methacrylic acid, maleic acid and maleic anhydride.

[0044] More preferably, the one or more polymers (I) are or are derived from a styrene / acrylic acid copolymer, preferably having a weight average molecular weight of 2000 to 40000 g / mol (determined by the method as described herein) and / or having an acid number of 70 to 300 mgKOH / gram of styrene / acrylic acid copolymer.

[0045] As used herein, the acid number of a polymer is determined titrimetrically according to ISO 2114-2000.

[0046] Even more preferably, the one or more polymers (I) are or are derived from styrene / maleic anhydride (SMA) copolymers, preferably having a weight average molecular weight of 4000 to 150000 g / mol (determined as described in the description) and / or having an acid number of 130 to 500 mg KOH / gram of SMA.

[0047] With glass transition temperature T g2 (one or more) polymers (II)

[0048] The heat-resistant coating further comprises one or more g1 The glass transition temperature T g2 A polymer wherein the T g2The one or more polymers (II) have a glass transition temperature T of at most 50°C, preferably at most 40°C, more preferably at most 30°C, even more preferably at most 25°C, even more preferably at most 20°C, even more preferably at most 15°C, even more preferably at most 10°C, even more preferably at most 5°C, as determined using differential scanning calorimetry as described herein. g2 .

[0049] The one or more polymers (II) preferably have a glass transition temperature T of at least -60°C, more preferably at least -50°C, even more preferably at least -40°C, even more preferably at least -30°C, even more preferably at least -25°C. g2 .

[0050] The one or more polymers have a glass transition temperature T g2 The heat-estimated mass content of the polymer (II) is preferably at least 15% by weight, more preferably at least 17.5% by weight, and the one or more polymers having a glass transition temperature T g2 The thermally estimated mass content of the polymer (II) is preferably at most 90% by weight, more preferably at most 85% by weight, even more preferably at most 80% by weight, wherein the one or more g2 The heat estimated mass content of the polymer is determined using the method as described herein.

[0051] Preferably, the one or more have a glass transition temperature T g2 The polymer (II) comprises

[0052] (B1) one or more ethylenically unsaturated monomers, and

[0053] (B2) optionally one or more carboxylic acid functional ethylenically unsaturated monomers different from (B1).

[0054] (One or more) monomers (B1) are preferably selected from acrylates, methacrylates, arylalkylenes, itaconic acid esters and any mixtures thereof. If (one or more) monomers (B2) are present, they are preferably selected from itaconic acid, itaconic anhydride, monoalkyl esters of itaconic acid, monoaryl esters of itaconic acid, acrylic acid, methacrylic acid, β-carboxyethyl acrylate and combinations thereof, more preferably, monomer (B2) is acrylic acid and / or methacrylic acid, and most preferably, monomer (B2) is acrylic acid. Preferably, at least 30% by weight, more preferably at least 50% by weight, and even more preferably at least 70% by weight of the total amount of monomers (B1) are selected from methyl methacrylate, n-butyl acrylate, n-butyl methacrylate, 2-ethylhexyl acrylate, 2-octyl acrylate, styrene and mixtures of two or more of said monomers. Preferably, monomer (B1) is a combination of one or more acrylates and one or more methacrylates. The amount of (one or more) monomers (B2) in polymer (II) is preferably at most 3% by weight, more preferably at most 2% by weight, and particularly preferably 0% by weight, and the amount of monomer (B1) is preferably at least 97% by weight, even more preferably at least 98% by weight, and particularly preferably 100% by weight. The amount of monomers (B1) and (B2) is given relative to the total weight of the monomers loaded in the polymerization for the preparation of polymer (II). The amount of monomers (B1) and (B2) preferably totals 100% by weight, i.e., the (one or more) monomers loaded in the polymerization for the preparation of polymer (II) are preferably composed of (one or more) monomers (B1) and optionally (one or more) monomers (B2).

[0055] T g1 and T g2 The difference is at least 100°C, preferably at least 110°C, more preferably at least 120°C and preferably at most 320°C, more preferably at most 295°C, more preferably at most 270°C, more preferably at most 245°C, more preferably at most 220°C.

[0056] The one or more have a glass transition temperature T g1 The amount of polymer (I) is related to the one or more having a glass transition temperature T g2 The ratio of the amount of polymer (II) to that of is preferably at least 1:5, more preferably at least 1:4 and preferably at most 5:1, more preferably at most 4:1, wherein the ratio is determined by the method as described in the present description.

[0057] The one or more heat-resistant coatings have a glass transition temperature T g1 Estimated heat content of the polymer by mass and the one or more having a glass transition temperature T g2The sum of the thermally estimated mass contents of the polymers is preferably at least 40% by weight, more preferably at least 50% by weight, relative to the total mass of the polymers present in the heat-resistant coating.

[0058] In a preferred embodiment of the present invention,

[0059] (i) the one or more polymers (I) have a glass transition temperature T of at least 150°C and at most 210°C g1 ,

[0060] (ii) the one or more polymers (I) have a thermally estimated mass content of at least 25% and at most 80% by weight relative to the total mass of polymers present in the heat-resistant coating,

[0061] (iii) the one or more polymers (II) have a glass transition temperature T of at least -30°C and at most 30°C, preferably at most 10°C, more preferably at most 5°C g2 ,

[0062] (iv) the thermally estimated mass content of the one or more polymers (II) is at least 15% by weight and at most 50% by weight, relative to the total mass of polymers present in the heat-resistant coating,

[0063] (v)T g1 and T g2 The difference between is at least 120°C and at most 220°C, and

[0064] (vi) the one or more materials have a glass transition temperature T g1 The amount of polymer (I) is related to the one or more having a glass transition temperature T g2 The ratio of the amount of polymer (II) is at least 1:2.5 and at most 3.25:1.

[0065] The one or more have a glass transition temperature T g2 The polymer preferably has a glass transition temperature T g1 Prepared in the presence of a polymer. g2 In this preferred embodiment of the present invention it is preferably at most 20°C, more preferably at most 15°C, even more preferably at most 10°C, even more preferably at most 5°C.

[0066] The substrate of the coated packaging film is a polymer-based substrate, and the polymer includes one or more polymers selected from polyethylene PE, oriented PE (eg machine-direction oriented PE (MDO PE), preferably BOPE) and any combination thereof.

[0067] The substrate of the coated packaging film is composed of at least 60% by weight, preferably at least 70% by weight, more preferably at least 80% by weight of a polymer selected from polyethylene PE, oriented PE and any combination thereof, based on the total weight of the substrate. Preferably, the substrate is composed of at least 60% by weight, preferably at least 70% by weight, more preferably at least 80% by weight of oriented polyethylene, based on the total weight of the substrate. The oriented polyethylene is preferably a machine-direction oriented polyethylene, and the oriented polyethylene is more preferably a biaxially oriented polyethylene (BOPE).

[0068] The substrate of the coated packaging film may be a single layer or may include multiple layers.

[0069] The heat sealable region is preferably formed from a polymer, more preferably a polyethylene polymer.The heat sealable region may for example be an extruded or blown film or a coating.

[0070] The heat-resistant coating preferably has a dry thickness of at least 0.05 μm, preferably at least 0.1 μm, more preferably at least 0.25 μm, even more preferably at least 0.4 μm and preferably at most 25 μm, more preferably at most 15 μm, even more preferably at most 10 μm, even more preferably at most 8 μm. One of the advantages of using a thin heat-resistant coating is that the rest of the packaging film can be made mostly of the same polymer type ("mono-material"), thereby facilitating recycling.

[0071] To further enhance recyclability, the weight fraction of the heat-resistant coating, relative to the total weight of the coated packaging film, is preferably at most 20 wt%, more preferably at most 15 wt%, more preferably at most 10 wt%, more preferably at most 7.5 wt%, more preferably at most 5 wt%, more preferably at most 2.5 wt%.

[0072] The heat resistant coating is preferably present at least in the critical areas that are in direct contact with the heat sealing bars and / or hot air during the heat sealing process. The heat resistant coating is preferably coextensive with at least 90% of the heat sealable area.

[0073] The coated packaging film can be advantageously used to form packaging articles, preferably flexible packaging articles, including pouches, bags and sachets, wherein the heat-resistant coating forms the outermost surface of the packaging article. The present invention also relates to packaging articles obtained by heat-sealing the coated packaging film of the first aspect of the present invention to a heat-sealable substrate, which can be the same coated packaging film or another heat-sealable substrate, wherein the heat-resistant coating forms the outermost surface of the packaging article. For example, when the coated packaging film is used to make a filled self-supporting bag, an exemplary method for producing the packaging article includes (i) folding the coated packaging film into the correct shape (optionally also making a W-shaped fold, which forms a gusset at the bottom of the pouch), (ii) sealing to form the side of the packaging article, thereby keeping one side open, (iii) cutting into individual pouches, (iv) filling the partially heat-sealed pouches, and (iv) heat-sealing the open side of the pouch that has not yet been heat-sealed.

[0074] The present invention is further defined by a set of exemplary embodiments listed below. Unless otherwise stated herein or unless a skilled person deems it technically obvious that it is not feasible, any one of the embodiments, aspects and preferred features or ranges disclosed in this application may be combined in any combination.

[0075] [1] A coated packaging film comprising:

[0076] (1) a heat-sealable substrate having a heat-sealable region and opposing surfaces on opposite sides of the heat-sealable region,

[0077] (2) a heat-resistant coating provided on at least a portion of the opposite surface of the substrate,

[0078] The heat-resistant coating comprises:

[0079] (I) one or more having a glass transition temperature T of at least 140°C g1 The polymer (I), and

[0080] (II) One or more having a value lower than T g1 and a glass transition temperature T of at most 50°C g2 The polymer (II)

[0081] Where T g1 and T g2 The difference between is at least 100°C,

[0082] Wherein T g1 and T g2 Determined by Differential Scanning Calorimetry as described in this specification.

[0083] [2] The packaging film according to embodiment [1], wherein the one or more polymers have a glass transition temperature T g1 The estimated thermal mass content of the polymer (I) is at least 7.5 wt. %, preferably at least 10 wt. %, more preferably at least 15 wt. %, even more preferably at least 5 wt. %, and the estimated thermal mass content of the one or more polymers (I) is at most 85 wt. %, more preferably at most 80 wt. %, even more preferably at most 75 wt. %, even more preferably at most 70 wt. %, relative to the total mass of polymers present in the heat-resistant coating, wherein the one or more polymers having T g1 The heat estimated mass content of the polymer is determined using the method as described herein.

[0084] [3] The packaging film according to embodiment [1] or [2], wherein the one or more polymers (I) have a glass transition temperature T of at least 142°C, more preferably at least 145°C, even more preferably at least 150°C and preferably at most 260°C, more preferably at most 250°C, even more preferably at most 240°C, even more preferably at most 230°C, more preferably at most 220°C. g1 .

[0085] [4] The packaging film according to any one of embodiments [1] to [3], wherein the one or more polymers (I) are or are derived from a polymer comprising:

[0086] one or more monomers (A1) selected from styrene, substituted styrene, acrylate, methacrylate and itaconate, and

[0087] One or more monomers (A2) selected from acrylic acid, β-carboxyethyl acrylate, methacrylic acid, maleic acid, maleic anhydride and itaconic acid.

[0088] [5] The packaging film according to embodiment [4], wherein the one or more monomers (A1) are selected from styrene and methacrylate, and the one or more monomers (A2) are selected from acrylic acid, methacrylic acid, maleic acid and maleic anhydride.

[0089] [6] A packaging film according to any one of the preceding embodiments [1] to [5], wherein the one or more polymers (I) are or are derived from a styrene / maleic anhydride (SMA) copolymer, preferably having a weight average molecular weight of 4000 to 150000 g / mol as determined by the method described in the present specification and / or having an acid number of 130 to 500 mg KOH / gram of SMA.

[0090] [7] A packaging film according to any one of embodiments [1] to [6], wherein the one or more polymers (I) are or are derived from a styrene / acrylic acid copolymer, preferably having a weight average molecular weight of 2000 to 40000 g / mol as determined by the method described in the specification and / or having an acid value of 70 to 300 mg KOH / gram of styrene / acrylic acid copolymer.

[0091] [8] The packaging film according to any one of embodiments [1] to [7], wherein T g1 and T g2 The difference is at least 110°C, preferably at least 120°C and preferably at most 320°C, more preferably at most 295°C, even more preferably at most 270°C, even more preferably at most 245°C, even more preferably at most 220°C.

[0092] [9] The packaging film according to any one of embodiments [1] to [8], wherein T g2 It is at least -60°C, preferably at least -50°C, more preferably at least -40°C, even more preferably at least -30°C, even more preferably at least -25°C, and preferably at most 40°C, more preferably at most 30°C, even more preferably at most 25°C, even more preferably at most 20°C, even more preferably at most 15°C, even more preferably at most 10°C, even more preferably at most 5°C.

[0093]

[10] The packaging film according to any one of embodiments [1] to [9], wherein the one or more polymers have a glass transition temperature T g2 The heat-estimated mass content of polymer (II) is at least 15% by weight, preferably at least 17.5% by weight, and the one or more polymers having a glass transition temperature T g2 The polymer (II) has a thermally estimated mass content of at most 90 wt %, preferably at most 85 wt %, more preferably at most 80 wt %, wherein the one or more g2 The heat estimated mass content of the polymer is determined using the method as described in this specification.

[0094]

[11] The packaging film according to any one of embodiments [1] to

[10] , wherein the one or more polymers have a glass transition temperature T g1 The amount of polymer (I) is related to the one or more having a glass transition temperature T g2 The ratio of the amount of polymer (II) to that of is at least 1:5, more preferably at least 1:4, and preferably at most 5:1, more preferably at most 4:1, wherein the ratio is determined by the method as described in the present specification.

[0095]

[12] The packaging film according to any one of embodiments [1] to

[11] , wherein

[0096] (i) the one or more polymers (I) have a glass transition temperature T of at least 150°C and at most 210°C g1 ,

[0097] (ii) the one or more polymers (I) have a thermally estimated mass content of at least 25% and at most 80% by weight relative to the total mass of polymers present in the heat-resistant coating,

[0098] (iii) the one or more polymers (II) have a glass transition temperature T of at least -30°C and at most 30°C, preferably at most 10°C, more preferably at most 5°C g2 ,

[0099] (iv) the thermally estimated mass content of the one or more polymers (II) is at least 15% by weight and at most 50% by weight, relative to the total mass of polymers present in the heat-resistant coating,

[0100] (v)T g1 and T g2 The difference between is at least 120°C and at most 220°C, and

[0101] (vi) the one or more materials have a glass transition temperature T g1 The amount of polymer (I) is related to the one or more having a glass transition temperature T g2 The ratio of the amount of polymer (II) is at least 1:2.5 and at most 3.25:1.

[0102]

[13] The packaging film according to any one of embodiments [1] to

[12] , wherein the one or more has a glass transition temperature T g2 The polymer (II) comprises

[0103] (B1) one or more ethylenically unsaturated monomers, and

[0104] (B2) optionally one or more carboxylic acid functional ethylenically unsaturated monomers different from (B1).

[0105]

[14] A packaging film according to embodiment

[13] , wherein if (one or more) monomers (B2) are present, they are selected from itaconic acid, itaconic anhydride, monoalkyl esters of itaconic acid, monoaryl esters of itaconic acid, acrylic acid, methacrylic acid, β-carboxyethyl acrylate and combinations thereof, more preferably, monomer (B2) is acrylic acid and / or methacrylic acid, and most preferably, monomer (B2) is acrylic acid; and / or (one or more) monomers (B1) are selected from acrylates, methacrylates, arylalkylenes, itaconic acid esters and any mixtures thereof.

[0106]

[15] A packaging film according to embodiment

[13] or

[14] , wherein at least 30 wt %, more preferably at least 50 wt %, and even more preferably at least 70 wt % of the total amount of monomer (B1) is selected from methyl methacrylate, n-butyl acrylate, n-butyl methacrylate, 2-ethylhexyl acrylate, 2-octyl acrylate, styrene and a mixture of two or more of said monomers.

[0107]

[16] A packaging film according to any one of embodiments

[13] to

[15] , wherein the amount of monomer (B2) in polymer B is at most 3 wt %, even more preferably at most 2 wt %, and particularly preferably 0 wt %, and the amount of monomer (B1) is preferably at least 97 wt %, even more preferably at least 98 wt %, and particularly preferably 100 wt %.

[0108]

[17] The packaging film according to any one of embodiments

[13] to

[16] , wherein (B1) is a combination of one or more acrylates and one or more methacrylates.

[0109]

[18] The packaging film according to any one of embodiments [1] to

[17] , wherein the one or more of the heat-resistant coatings have a glass transition temperature T g1 Estimated heat content of the polymer by mass and the one or more having a glass transition temperature T g2 The sum of the thermally estimated mass contents of the polymers is at least 40 wt%, more preferably at least 50 wt%, relative to the total mass of the polymers present in the heat-resistant coating.

[0110]

[19] The packaging film according to any one of embodiments [1] to

[18] , wherein the one or more polyols have a glass transition temperature T g2 The polymer has a glass transition temperature T g1 prepared in the presence of a polymer.

[0111]

[20] The packaging film according to any one of embodiments [1] to

[19] , wherein the substrate is a polymer-based substrate, and the polymer comprises one or more polymers selected from polyethylene PE, oriented PE (preferably BOPE) and any combination thereof.

[0112]

[21] A packaging film according to any one of embodiments [1] to

[20] , wherein the substrate consists of at least 60 wt %, preferably at least 70 wt %, and more preferably at least 80 wt %, of a polymer selected from polyethylene (PE), oriented polyethylene, and any combination thereof, based on the total weight of the substrate.

[0113]

[22] The packaging film according to any one of embodiments [1] to

[21] , wherein the substrate consists of at least 60 wt%, preferably at least 70 wt%, more preferably at least 80 wt% of oriented polyethylene based on the total weight of the substrate.

[0114]

[23] A packaging film according to any one of embodiments [1] to

[21] , wherein the substrate consists of at least 60 wt%, preferably at least 70 wt%, more preferably at least 80 wt% of machine-direction oriented polyethylene, based on the total weight of the substrate.

[0115]

[24] A packaging film according to any one of embodiments [1] to

[21] , wherein the substrate consists of at least 60 wt%, preferably at least 70 wt%, and more preferably at least 80 wt% of biaxially oriented polyethylene (BOPE), based on the total weight of the substrate.

[0116]

[25] A packaging film according to any one of embodiments [1] to

[24] , wherein the heat-resistant coating is obtained as follows: (1) an aqueous coating composition is disposed on at least a portion of the substrate on the side of the substrate opposite to the side where the heat-sealable area is located, and (2) the aqueous coating composition is dried to provide the heat-resistant coating on at least a portion of the first surface of the substrate.

[0117]

[26] A packaging film according to any one of embodiments [1] to

[25] , wherein the heat-resistant coating has a dry thickness of at least 0.05 μm, preferably at least 0.1 μm, more preferably at least 0.25 μm, more preferably at least 0.4 μm and preferably at most 25 μm, more preferably at most 15 μm, more preferably at most 10 μm, more preferably at most 8 μm.

[0118]

[27] The packaging film according to any one of embodiments [1] to

[26] , wherein the heat-resistant coating is present at least in a critical area that is in direct contact with a heat sealing bar and / or hot air during a heat sealing process.

[0119]

[28] The packaging film according to any one of embodiments [1] to

[27] , wherein the heat-sealable region is formed of a polymer, preferably a polyethylene polymer.

[0120]

[29] The packaging film according to any one of embodiments [1] to

[28] , wherein the substrate is a single layer or includes a plurality of layers.

[0121]

[30] The packaging film according to any one of embodiments [1] to

[29] , wherein the heat-sealable region is an extruded film or a blown film or a coating.

[0122]

[31] A packaging film according to any one of embodiments [1] to

[30] , wherein the packaging film is used to form packaging articles, including pouches, bags and sachets, wherein the heat-resistant coating forms the outermost surface of the packaging article.

[0123]

[32] A packaging article obtained by heat sealing the coated packaging film according to any one of embodiments [1] to

[31] to a heat-sealable substrate, which may be the same coated packaging film or another heat-sealable substrate, wherein the heat-resistant coating forms the outermost surface of the packaging article.

[0124]

[33] A substrate having a first surface, wherein the substrate comprises a heat-resistant coating disposed on at least a portion of the first surface, the substrate being intended for use in producing a heat-sealable packaging film having a heat-sealable area on the opposite side of the heat-resistant coating, wherein the heat-resistant coating comprises

[0125] (I) one or more having a glass transition temperature T of at least 140°C, more preferably at least 142°C, more preferably at least 145°C, preferably at least 150°C and preferably at most 260°C, more preferably at most 250°C, more preferably at most 240°C, more preferably at most 230°C, more preferably at most 220°C g1 The polymer (I), and

[0126] (II) One or more having a value lower than T g1 and a glass transition temperature T of at most 50°C g2 The polymer (II)

[0127] Where T g1 and T g2 The difference between the two is at least 100°C, where the T g1 and T g2 Determined by Differential Scanning Calorimetry as described in this specification.

[0128]

[34] A substrate according to embodiment

[33] , wherein the one or more polymers have a glass transition temperature T g1 The estimated thermal mass content of the polymer (I) is at least 7.5% by weight, preferably at least 10% by weight, more preferably at least 15% by weight, even more preferably at least 20% by weight, and the estimated thermal mass content of the one or more polymers (I) is at most 85% by weight, preferably at most 80% by weight, more preferably at most 75% by weight, even more preferably at most 70% by weight, relative to the total mass of polymers present in the heat-resistant coating, wherein the one or more polymers having T g1 The heat estimated mass content of the polymer is determined using the method as described herein.

[0129]

[35] The substrate according to any one of embodiments

[33] to

[34] , wherein the one or more polymers (I) are or are derived from a polymer comprising:

[0130] one or more monomers (A1) selected from styrene, substituted styrene, acrylate, methacrylate and itaconate, and

[0131] One or more monomers (A2) selected from acrylic acid, β-carboxyethyl acrylate, methacrylic acid, maleic acid, maleic anhydride and itaconic acid.

[0132]

[36] The substrate according to embodiment

[35] , wherein the one or more monomers (A1) are selected from styrene and methacrylate, and the one or more monomers (A2) are selected from acrylic acid, methacrylic acid, maleic acid and maleic anhydride.

[0133]

[37] A substrate according to any one of the preceding embodiments

[35] to

[36] , wherein the one or more polymers (I) are or are derived from styrene / maleic anhydride (SMA) copolymers, preferably having a weight average molecular weight of 4000 to 150000 g / mol as determined by the method described in this specification and / or having an acid number of 130 to 500 mg KOH / gram of SMA.

[0134]

[38] A substrate according to any one of embodiments

[33] to

[37] , wherein the one or more polymers (I) are or are derived from a styrene / acrylic acid copolymer, which preferably has a weight average molecular weight of 2000 to 40000 g / mol and / or an acid value of 70 to 300 mg KOH / gram of styrene / acrylic acid copolymer as determined by the method described in this specification.

[0135]

[39] The substrate according to any one of embodiments

[33] to

[38] , wherein T g1 and T g2The difference is at least 110°C, preferably at least 120°C and preferably at most 320°C, more preferably at most 295°C, even more preferably at most 270°C, even more preferably at most 245°C, even more preferably at most 220°C.

[0136]

[40] The substrate according to any one of embodiments

[33] to

[39] , wherein T g2 It is at least -60°C, preferably at least -50°C, more preferably at least -40°C, even more preferably at least -30°C, even more preferably at least -25°C, and preferably at most 40°C, more preferably at most 30°C, even more preferably at most 25°C, even more preferably at most 20°C, even more preferably at most 15°C, even more preferably at most 10°C.

[0137]

[41] A substrate according to any one of embodiments

[33] to

[40] , wherein the one or more polymers have a glass transition temperature T g2 The heat-estimated mass content of polymer (II) is at least 15% by weight, preferably at least 17.5% by weight, and the one or more polymers having a glass transition temperature T g2 The polymer (II) has a thermally estimated mass content of at most 90 wt %, preferably at most 85 wt %, more preferably at most 80 wt %, wherein the one or more g2 The heat estimated mass content of the polymer is determined using the method as described in this specification.

[0138]

[42] A substrate according to any one of embodiments

[33] to

[41] , wherein the one or more substrates have a glass transition temperature T g1 The amount of polymer (I) is related to the one or more having a glass transition temperature T g2 The ratio of the amount of polymer (II) to that of is at least 1:5, more preferably at least 1:4, and preferably at most 5:1, more preferably at most 4:1, wherein the ratio is determined by the method as described in the present specification.

[0139]

[43] The substrate according to any one of embodiments

[33] to

[42] , wherein

[0140] (i) the one or more polymers (I) have a glass transition temperature T of at least 150°C and at most 210°C g1 ,

[0141] (ii) the one or more polymers (I) have a thermally estimated mass content of at least 25% and at most 80% by weight relative to the total mass of polymers present in the heat-resistant coating,

[0142] (iii) the one or more polymers (II) have a glass transition temperature T of at least -30°C and at most 30°C, preferably at most 10°C, more preferably at most 5°C g2 ,

[0143] (iv) the thermally estimated mass content of the one or more polymers (II) is at least 15% by weight and at most 50% by weight, relative to the total mass of polymers present in the heat-resistant coating,

[0144] (v)T g1 and T g2 The difference between is at least 120°C and at most 220°C, and

[0145] (vi) the one or more materials have a glass transition temperature T g1 The amount of polymer (I) is related to the one or more having a glass transition temperature T g2 The ratio of the amount of polymer (II) is at least 1:2.5 and at most 3.25:1.

[0146]

[44] A substrate according to any one of embodiments

[33] to

[43] , wherein the one or more substrates have a glass transition temperature T g2 The polymer (II) comprises

[0147] (B1) one or more ethylenically unsaturated monomers, and

[0148] (B2) optionally one or more carboxylic acid functional ethylenically unsaturated monomers different from (B1).

[0149]

[45] A substrate according to embodiment

[44] , wherein if (one or more) monomers (B2) are present, they are selected from itaconic acid, itaconic anhydride, monoalkyl esters of itaconic acid, monoaryl esters of itaconic acid, acrylic acid, methacrylic acid, β-carboxyethyl acrylate and combinations thereof, more preferably, monomer (B2) is acrylic acid and / or methacrylic acid, and most preferably, monomer (B2) is acrylic acid; and / or (one or more) monomers (B1) are selected from acrylates, methacrylates, arylalkylenes, itaconic acid esters and any mixtures thereof.

[0150]

[46] A substrate according to embodiment

[44] or

[45] , wherein at least 30 wt %, more preferably at least 50 wt %, and even more preferably at least 70 wt % of the total amount of monomer (B1) is selected from methyl methacrylate, n-butyl acrylate, n-butyl methacrylate, 2-ethylhexyl acrylate, 2-octyl acrylate, styrene and a mixture of two or more of said monomers.

[0151]

[47] A substrate according to any one of embodiments

[44] to

[46] , wherein the amount of monomer (B2) in polymer B is at most 3 wt %, preferably at most 2 wt %, and particularly preferably 0 wt %, and the amount of monomer (B1) is preferably at least 97 wt %, even more preferably at least 98 wt %, and particularly preferably 100 wt %.

[0152]

[48] ​​The substrate according to any one of embodiments

[44] to

[47] , wherein (B1) is a combination of one or more acrylates and one or more methacrylates.

[0153]

[49] A substrate according to any one of embodiments

[33] to

[48] , wherein the one or more of the heat-resistant coatings have a glass transition temperature T g1 Estimated heat content of the polymer by mass and the one or more having a glass transition temperature T g2 The sum of the thermally estimated mass contents of the polymers is at least 40% by weight, preferably at least 50% by weight, relative to the total mass of the polymers present in the heat-resistant coating.

[0154]

[50] A substrate according to any one of embodiments

[33] to

[49] , wherein the one or more substrates have a glass transition temperature T g2 The polymer has a glass transition temperature T g1 prepared in the presence of a polymer.

[0155]

[51] The substrate according to any one of embodiments

[33] to

[50] , wherein the substrate is a polymer-based substrate, and the polymer comprises one or more polymers selected from polyethylene PE, oriented PE (preferably BOPE) and any combination thereof.

[0156]

[52] A substrate according to any one of embodiments

[33] to

[51] , wherein the substrate consists of at least 60 wt%, preferably at least 70 wt%, and more preferably at least 80 wt%, of a polymer selected from polyethylene (PE), oriented polyethylene, and any combination thereof, based on the total weight of the substrate.

[0157]

[53] A substrate according to any one of embodiments

[33] to

[52] , wherein the substrate consists of at least 60 wt%, preferably at least 70 wt%, and more preferably at least 80 wt% of oriented polyethylene based on the total weight of the substrate.

[0158]

[54] A substrate according to any one of embodiments

[33] to

[53] , wherein the substrate consists of at least 60 wt%, preferably at least 70 wt%, and more preferably at least 80 wt% of machine-direction oriented polyethylene based on the total weight of the substrate.

[0159]

[55] A substrate according to any one of embodiments

[33] to

[54] , wherein the substrate consists of at least 60 wt%, preferably at least 70 wt%, and more preferably at least 80 wt% of biaxially oriented polyethylene (BOPE), based on the total weight of the substrate.

[0160]

[56] A substrate according to any one of embodiments

[33] to

[55] , wherein the heat-resistant coating is obtained as follows: (1) disposing an aqueous coating composition on at least a portion of the substrate on the side of the substrate opposite to the side where the heat-sealable area is located, and (2) drying the aqueous coating composition to provide the heat-resistant coating on at least a portion of the first surface of the substrate.

[0161]

[57] A substrate according to any one of embodiments

[33] to

[56] , wherein the heat-resistant coating has a dry thickness of at least 0.05 μm, preferably at least 0.1 μm, more preferably at least 0.25 μm, more preferably at least 0.4 μm and preferably at most 25 μm, more preferably at most 15 μm, more preferably at most 10 μm, more preferably at most 8 μm.

[0162]

[58] A substrate according to any one of embodiments

[33] to

[57] , wherein the heat-resistant coating is present at least in critical areas that are in direct contact with heat sealing bars and / or hot air during the heat sealing process.

[0163]

[59] The substrate according to any one of embodiments

[33] to

[58] , wherein the heat-sealable region is formed of a polymer, preferably a polyethylene polymer.

[0164]

[60] The substrate according to any one of embodiments

[33] to

[59] , wherein the substrate is a single layer or includes a plurality of layers.

[0165]

[61] The substrate according to any one of embodiments

[33] to

[60] , wherein the heat-sealable region is an extruded film or a blown film or a coating.

[0166]

[62] A substrate according to any one of embodiments

[33] to

[61] , wherein the substrate is used to form a packaging article, including pouches, bags and sachets, wherein the heat-resistant coating forms the outermost surface of the packaging article.

[0167]

[63] A packaging film comprising a coated substrate as defined in any one of embodiments

[33] to

[62] , wherein the coated substrate includes a heat-sealable area on the opposite side of the heat-resistant coating, or wherein the packaging film further comprises one or more additional layers arranged on the second surface of the coated substrate as defined in any one of embodiments

[33] to

[62] , the second surface being on the opposite side of the heat-resistant coating, wherein the one or more additional layers include a heat-sealable area on the opposite side of the heat-resistant coating.

[0168]

[64] A packaging article obtained by heat sealing the coated packaging film according to embodiment

[63] to a heat-sealable substrate, which can be the same coated packaging film or another heat-sealable substrate, wherein the heat-resistant coating forms the outermost surface of the packaging article.

[0169] The invention will now be illustrated by reference to the following examples. Unless otherwise indicated, all parts, percentages and ratios are by weight.

[0170] Method for calculating dry film thickness

[0171] The dry film thickness was calculated by multiplying the wet film thickness by the solids content of the formulation used.

[0172] DFT = WFT * solid content / 100

[0173] in

[0174] DFT: Dry film thickness in μm

[0175] WFT: wet film thickness in μm

[0176] Solid content (wt%): the total weight of all solid compounds present in the formulation divided by (total weight of the formulation*100).

[0177] Measurement method

[0178] Average particle size PS:

[0179] The intensity average particle size, z-average, was determined by photon correlation spectroscopy using a Malvern Zetasizer Nano ZS. The sample was diluted in demineralized water to a concentration of about 0.1 g dispersion / liter. The measurement temperature was 25°C. The laser incident angle was 173°. The laser wavelength was 633 nm.

[0180] pH

[0181] The pH was measured using a Metrohm pH meter.

[0182] Solid content

[0183] The solids content of the dispersions was measured on a HB43-S halogen moisture analyzer from Mettler Toledo at a temperature of 130°C.

[0184] Viscosity

[0185] Viscosity was measured using a Brookfield LV (spindle 2, 60 rpm, room temperature).

[0186] The glass transition temperature T was determined by differential scanning calorimetry (DSC). g1 , T g2 , with T g1 (one or more) Estimation of heat content of polymer by mass and with T g2 Estimated heat mass content of polymers with T g1 (one or more The amount of polymer with T g2 The ratio of the amount of polymer

[0187] The thermal transitions of the samples were studied by DSC and the glass transition temperatures were assigned according to ASTM E 1356.

[0188] The measurements were carried out with a DSC 250 from TA Instruments; a nitrogen atmosphere was used for all measurements. Indium was used for enthalpy and temperature calibration of the instrument, and an empty Tzero aluminum pan was used as a reference.

[0189] About 5 mg of sample was placed in a non-sealed Tzero aluminum pan and fully dried under nitrogen before measurement. Drying conditions of 180°C for 1 hour were used. The weight of the sample was measured after drying and the glass transition temperature was subsequently determined as described below.

[0190] Glass transition temperature is measured and specified according to ASTM E 1356.

[0191] The sample was heated to 210°C at 10°C / min to remove the thermal history and then cooled to -90°C at 20°C / min. Heating from -90°C to 220°C at 10°C / min was used for identification of Tg. Other temperature ranges for the heating step may be required depending on the location of the glass transition temperature, as described in ASTM E 1356 and as known to those skilled in the art.

[0192] The heating curve is used to assign the glass transition temperature(s), where the midpoint temperature of the transition is taken as T g In addition, the change in specific heat capacity ΔC at each identified glass transition i in the sample has been determined between the extrapolated end temperature and the extrapolated start temperature of that transition. p,i .

[0193] It has been assumed that each identified glass transition corresponds to a The specific heat capacity inherent in a phase changes.

[0194] With T g1 The amount of (one or more) polymers with Tg2 The ratio of the amount of (one or more) polymers

[0195] To calculate the ratio of the amount of polymer material in the phases corresponding to the multiple transitions, it has been assumed that the material in each phase has the same intrinsic change in specific heat capacity

[0196] In the sample with T g1 The glass transition in the range of T g2 In the case of glass transition within the range, with T g1 The amount of polymer with T g2 The ratio of the amount of polymers is based on the ratio: ΔC p,1 :ΔC p,2 calculate.

[0197] In one or more having g1 T in the range g phase n and one or more having at T g2 T in the range g In the case of phase m, with T g1 T in the range g The amount of polymer with T g2 T in the range g The ratio of the amount of polymers is according to the ratio:∑ n ΔC p,1,n :∑ m ΔC p,2,m calculate.

[0198] With T g1 The estimated heat content of the polymer(s) by mass and having T g2 Estimated heat content of polymer(s)

[0199] By assuming that each transition has To calculate the heat estimated mass content m of each phase i in the total sample i .

[0200] Then according to m i =|ΔC p,i | / (0.45 J / g-°C) x 100% Calculate the estimated heat content. In the case where the estimated heat content is > 100%, it is rounded to 100%. Because this is an estimated content, the sum of the estimated heat content of all phases can be greater than 100%.

[0201] Determination of number average molecular weight, weight average molecular weight, z average molecular weight and molecular weight distribution

[0202] The number average molecular weight, weight average molecular weight, z average molecular weight and molecular weight distribution were determined by size exclusion chromatography in THF HAC 0.8% at 40°C on a Waters Alliance 2695LC system with a Waters 2410DRI detector using two PLgel 10 μm Mixed-C columns. Tetrahydrofuran 100% (THF HAC 0.8%) containing 0.8% v / v acetic acid was used as the eluent at a flow rate of 1 mL / min. The samples were dissolved in the eluent using a concentration of 5 mg polymer / mL solvent. The solubility was judged with a laser pen after stabilization for 24 hours at room temperature; if any scattering was visible, the sample was first filtered and 150 μl of the sample solution was injected (0.45 μm PTFE filter). M was calculated using narrow polystyrene standards ranging from 162 to 1730000 Da. W (weight average molecular weight), M z (z-average molecular weight) and MWD (molecular weight distribution) results.

[0203] Abbreviations and raw materials used :

[0204] SGO = Solid Grade Oligomer

[0205] kD = kilodaltons

[0206] Mw = weight average molecular weight

[0207] Tg = glass transition temperature

[0208] KOH = Potassium Hydroxide

[0209] BMA = n-butyl methacrylate

[0210] 2-EHA = 2-ethylhexyl acrylate

[0211] BA = n-butyl acrylate

[0212] i-BMA = isobutyl methacrylate

[0213] mPa.s = millipascal-second

[0214] μm = micrometer

[0215] nm = nanometer

[0216] PSD = Particle Size Distribution

[0217] Dilution water = demineralized water added when cooled to 25°C

[0218] Solid Grade Oligomers 2500, 3500 and 4000 supplied by Polyscope.

[0219] Solid grade oligomer Indurez SR 10PG was supplied by Indulor.

[0220] 2500H was supplied by Polyscope as a 15 wt% solids solution at pH 9.1.

[0221] Synthesis of coating compositions

[0222] Synthesis of coating composition E1

[0223] 719.17 grams of demineralized water were added to a 4-neck 2-liter round bottom glass reactor.

[0224] Add 146.91 g of solid oligomer under stirring 2500 (supplied by Polyscope), then 77.44 g of ammonia (25% solution in demineralized water) were added. The reactor contents were heated to 85°C and mixed at 85°C until 2500 is completely dissolved. Then a nitrogen flow of 0.2 l / min is started and the condenser water is turned on. A solution of 0.64 grams of ammonium persulfate dissolved in 1.73 grams of demineralized water is added to the reactor within 2 minutes and the reactor contents are mixed for 5 minutes. A mixture of 56.17 grams of n-butyl methacrylate and 22.94 grams of 2-ethylhexyl acrylate is loaded into feed funnel A. A solution of 0.64 grams of ammonium persulfate dissolved in 18.56 grams of demineralized water and 0.09 grams of ammonia (25% solution in demineralized water) is loaded into feed funnel B. After holding for 5 minutes, the contents of the two feed funnels are added to the reactor at 85° C. within 30 minutes. Feed funnel A is rinsed with 4.79 grams of demineralized water. The reactor contents are mixed for 30 minutes at 85° C. A solution of 0.32 grams of ammonium persulfate dissolved in 9.28 grams of demineralized water and 0.04 grams of ammonia (25% solution in demineralized water) were then added to the reactor over 30 minutes. After addition, the reactor contents were mixed for 30 minutes. 127.00 grams of demineralized water were then added to the reactor as dilution water, and the reactor contents were cooled to 25° C. 3.69 grams of biocide Proxel Ultra 10 were added to the reactor from the feed funnel over 1 minute. The feed funnel was rinsed with 0.42 grams of demineralized water. The reactor contents were mixed for 15 minutes and then filtered through a 200 mesh screen.

[0225] After drying at 130° C. using an IR dryer, the batch had a solids content of 19.1%. The pH was 9.4 and the Brookfield viscosity was 340 mPa.s. The particle size was measured using photon correlation spectroscopy and a value of 70 nm was observed with a particle size distribution of 0.27.

[0226] The measured Tg shifts were 180°C and -16°C, respectively, with |ΔC p,1 |=0.24J / g-℃ and |ΔC p,2 |=0.14J / g-℃. With T g1 The amount of polymer: with T g2 The ratio of the amount of polymer is therefore 1.7:1, and has T g1 The phase and T g2 The thermally estimated mass contents of the phases are 53% and 31%, respectively.

[0227] Synthesis of coating compositions E2, E3, C1, C2, C3, C4

[0228] Additional coating compositions were prepared according to the procedure as described for coating composition E1 using the adjusted amounts shown in Table 1, otherwise keeping the rest of the synthesis steps the same. The resulting specifications and the measured DSC transitions are shown in Table 1.

[0229] Table 1

[0230]

[0231] Synthesis of coating composition E4

[0232] 603.42 grams of demineralized water were added to a 4-neck 2-liter round bottom glass reactor.

[0233] Add 102.84 g of solid oligomer under stirring 2500 (supplied by Polyscope), then 54.21 g of ammonia (25% solution in demineralized water) were added. The reactor contents were heated to 85°C and mixed at 85°C until 2500 is completely dissolved. Then a nitrogen flow of 0.2l / min is started and the condenser water is turned on. A solution of 1.55 grams of ammonium persulfate dissolved in 4.18 grams of demineralized water and 0.21 grams of ammonia (25% solution in demineralized water) are added to the reactor within 2 minutes and the reactor contents are mixed for 5 minutes. A mixture of 135.60 grams of n-butyl methacrylate and 55.38 grams of 2-ethylhexyl acrylate is loaded into feed funnel A. A solution of 1.55 grams of ammonium persulfate dissolved in 44.95 grams of demineralized water and 0.21 grams of ammonia (25% solution in demineralized water) is loaded into feed funnel B. After holding for 5 minutes, the contents of the two feed funnels are added to the reactor at 85°C within 75 minutes. After 50 minutes of feeding, 25 grams of demineralized water are added every 5 minutes. Feed funnel A is rinsed with 11.57 grams of demineralized water. The reactor contents are mixed at 85°C for 30 minutes. A solution of 0.77 grams of ammonium persulfate dissolved in 22.48 grams of demineralized water and 0.11 grams of ammonia (25% solution in demineralized water) were then added to the reactor over 30 minutes. After addition, the reactor contents were mixed for 30 minutes. The reactor contents were then cooled to 25° C. From the feed funnel, 2.58 grams of the biocide Proxel Ultra 10 were added to the reactor over 1 minute. The feed funnel was rinsed with 0.29 grams of demineralized water. The reactor contents were mixed for 15 minutes and then filtered through a 200 mesh screen.

[0234] After drying at 130° C. using an IR dryer, the batch had a solids content of 24.5%. The pH was 8.8 and the Brookfield viscosity was 33 mPa.s. The particle size was measured using photon correlation spectroscopy and a value of 139 nm was observed with a particle size distribution of 0.28.

[0235] Synthesis of coating composition C5

[0236] 526.96 grams of demineralized water were added to a 4-neck 2-liter round bottom glass reactor.

[0237] 102.84 grams of solid grade oligomer Indurez SR 10PG (supplied by Indulor) were added under stirring, followed by 40.67 grams of ammonia (25% solution in demineralized water). The reactor contents were heated to 85°C and mixed at 85°C until the Indurez SR 10PG was completely dissolved. A nitrogen flow of 0.2 l / min was then started and the condenser water was turned on. A solution of 1.55 grams of ammonium persulfate dissolved in 4.18 grams of demineralized water and 0.21 grams of ammonia (25% solution in demineralized water) was added to the reactor over 2 minutes and the reactor contents were mixed for 5 minutes. A mixture of 135.60 grams of n-butyl methacrylate and 55.38 grams of 2-ethylhexyl acrylate was loaded into feed funnel A. A solution of 1.55 grams of ammonium persulfate dissolved in 44.95 grams of demineralized water and 0.21 grams of ammonia (25% solution in demineralized water) was loaded into feed funnel B. The contents of the two feed funnels were added to the reactor at 85°C over 75 minutes after holding for 5 minutes. Feed funnel A was rinsed with 11.57 grams of demineralized water. The reactor contents were mixed at 85°C for 30 minutes. A solution of 0.77 grams of ammonium persulfate dissolved in 22.48 grams of demineralized water and 0.11 grams of ammonia (25% solution in demineralized water) were then added to the reactor over 30 minutes. After addition, the reactor contents were mixed for 30 minutes. The reactor contents were then cooled to 25°C. From the feed funnel, 2.58 grams of the biocide Proxel Ultra 10 were added to the reactor over 1 minute. The feed funnel was rinsed with 0.29 grams of demineralized water. The reactor contents were mixed for 15 minutes and then filtered through a 200 mesh screen.

[0238] After drying at 130° C. using an IR dryer, the batch had a solids content of 31.2%. The pH was 8.6 and the Brookfield viscosity was 9 mPa.s. The particle size was measured using photon correlation spectroscopy and a value of 55 nm was observed with a particle size distribution of 0.10.

[0239] The compositions and specifications of coating compositions E4 and C5 are summarized in Table 2 together with the measured DSC transitions.

[0240] Table 2

[0241]

[0242] Coating composition C6

[0243] Coating composition C6 was obtained from Polyscope as a 15 wt% solids solution at a pH of 9.1. 2500H composition. This sample has a single measured Tg transition of 185°C with |ΔC p,1 |=0.43J / g-℃.

[0244] Preparation of coating composition E5

[0245] Synthesis of acrylic binder as part of coating composition E5

[0246] 950.20 grams of demineralized water were added to a 4-neck 2-liter round-bottom glass reactor. Under stirring, 33.17 grams of sodium dodecyl sulfate (supplied as a 30% aqueous solution) were added to the reactor. The reactor contents were heated to 80°C. Then a nitrogen flow of 0.2 l / min was started and the condenser water was turned on. A mixture of 190.23 grams of methyl methacrylate, 233.46 grams of n-butyl acrylate and 8.65 grams of methacrylic acid was loaded into feed funnel A. A solution of 2.17 grams of ammonium persulfate dissolved in 7.50 grams of demineralized water was loaded into feed funnel B. An amount of 5% by weight of the contents of feed funnel A was added to the reactor within 1 minute, and then the entire contents of feed funnel B were immediately added within 3 minutes. The reactor contents were mixed for 10 minutes to raise the reactor temperature to 85°C. The remainder of feed funnel A was then added to the reactor within 60 minutes while the temperature was maintained at 83 to 87°C. Feed funnel A was rinsed with 7.50 grams of demineralized water. The reactor contents were mixed at 83 to 87°C for 60 minutes. The reactor contents were then cooled to 25°C. 6.79 grams of ammonia (25% solution in demineralized water) were then added to the reactor. From the feed funnel, 9.00 grams of the biocide Proxel Ultra 10 were added to the reactor over 1 minute. The feed funnel was rinsed with 1.87 grams of demineralized water. The reactor contents were mixed for 15 minutes and then filtered through a 200 mesh sieve. After drying at 160°C using an IR dryer, the batch had a solids content of 30.0%. The pH was 8.3 and the Brookfield viscosity was 10 mPa.s. The particle size was measured using photon correlation spectroscopy and a value of 44 nanometers was observed with a particle size distribution of 0.04.

[0247] 16.0 g of the acrylic adhesive prepared as described above was blended with 30.0 g of 2500H solution was used to prepare coating composition E5.

[0248] The measured Tg transitions were 185°C and 21°C, respectively, with |ΔC p,1 |=0.17J / g-℃ and |ΔC p,2 |=0.21J / g-℃. With T g1 The amount of polymer: with T g2 The ratio of the amount of polymer is therefore 0.81:1, and has T g1 The phase and T g2 The thermally estimated mass contents of the phases are 38% and 47%, respectively.

[0249] Preparation of heat sealable films

[0250] By using 2.5g / m 2 Novacote NC-275-A from Coim with co-reactant CA-12 as laminating adhesive was applied and cured at room temperature for 48 hours. Silvalac PS525 heat sealable blown PE film with a thickness of 30 μm from Silvalac was laminated to Ethy-Lyte from Jindal. TM 20HD200 BOPE film to prepare a heat-sealable film consisting mainly of oriented polyethylene. The "treated" surface of the BOPE film (as indicated by the supplier) was positioned to form the outer surface of the film, opposite to the heat-sealable blown PE surface.

[0251] The outer surface of the BOPE was corona treated just before the coating compositions (inventive and comparative) were applied to the heat sealable film. The coating compositions were diluted with water to 15 wt% solids and then applied to the outer surface of the BOPE by a wire rod at a wet thickness of 24 μm. The coatings were dried in a hot air oven at 80°C for 20 seconds and allowed to stand at room temperature for at least 24 hours. The samples were cut into strips of 15 mm width and about 250 mm length using a Brugger strip cutter STR.

[0252] Heat resistance test

[0253] For heat resistance testing of coated samples as well as uncoated reference substrates (Comparative Experiment A), two identical sample strips were stacked with the heat-sealable blow molded PE surfaces in contact and the coated surface or uncoated BOPE surface oriented outward to form a stacked specimen for testing. Figure 1 The heat sealing operation is performed while holding the specimen under tension using a Brugger HSG-CC laboratory hot-jaw sealer with a HotTack device, in the configuration schematically shown in FIG. One end of the stacked specimen (1) is clamped in the clamp (2) of the HotTack device, and the other end of the stacked specimen is clamped in a single 50 gram drop weight (3). The specimen is suspended and positioned on the cylindrical mandrel (4) of the HotTack device so that a heat sealing operation can be performed with a heat-sealing jaw (5) on the specimen tensioning area between the clamp (2) and the mandrel (4).

[0254] Figure 1 : Schematic diagram of the test configuration used to test the thermal resistance of samples.

[0255] 1. Test specimen (consisting of two stacked sample strips as described above)

[0256] 2.Hot Tack fixture

[0257] 3. Drop hammer

[0258] 4.Cylindrical mandrel for Hot Tack device

[0259] 5. Heat sealing pliers (the long dimension of the pliers is oriented perpendicular to the long dimension of the test specimen)

[0260] Heat seal testing was performed with two Teflonized sealing jaws (40 mm x 20 mm size). The lower jaw was not heated, and the upper jaw was heated to a set temperature. Heat sealing was performed under conditions of 0.4 second sealing time and 780 Newton applied force. The heat seal was first applied at a heating jaw temperature set to 140°C. Further testing was then performed - the stacked specimen was repositioned in the Hot Tack device fixture to apply a heat seal to a new area of ​​the specimen (or a new pair of sample strips was used as a new test specimen), and the heating jaw temperature was gradually increased in increments of 10°C until visible deformation / damage of the specimen was observed after sealing, such as melting, sticking, shrinking, stretching or breaking. The formation of the heat seal bonding the two sample strips was verified by visual and physical inspection.

[0261] The embodiments of the present invention exhibit an increase in the temperature at which visible deformation / damage occurs while not preventing heat seal formation.

[0262] Comparative Experiment A

[0263] In Comparative Experiment A, no coating was applied to the heat-sealable film, which was then tested as an uncoated ("blank") sample. Figure 2 Results are shown for heat sealing this sample as described with jaw temperatures of 140° C., 150° C., and 160° C. Stretching and deformation occurred when heat sealing at 150° C. and above. Therefore, for the coated samples, 140° C. was used as the reference temperature for calculating the increase in temperature resistance.

[0264] Examples 1-5

[0265] In Example 1, a heat-sealable film was coated with coating composition E1 as described and tested for heat resistance as described above. Figure 3 , a photograph of the sample after testing is shown. Unlike the uncoated reference substrate, at clamp temperatures of 150°C and 160°C, the sample did not deform. At 170°C, deformation and shrinkage were visible. Since the sample was able to withstand a temperature of 160°C, this example has a +20°C improvement in temperature resistance relative to the uncoated reference.

[0266] In Examples 2-5, heat-sealable films were coated with coating compositions E2-E5 as described above and tested for heat resistance as described above.

[0267] In Examples 2 and 3, the coating films were found to have an improvement in temperature resistance of +20° C. In Examples 4 and 5, the coating films were found to have an improvement in temperature resistance of +10° C.

[0268] The heat resistance results for Examples 1-5 are reported in Table 3.

[0269] Table 3

[0270]

[0271]

[0272] Comparative experiment BG

[0273] For Comparative Experiments BG, coating compositions C1-C6 were applied to heat-sealable films as described, and tested for heat resistance as described above. In all cases, no improvement in temperature resistance was observed relative to the uncoated substrate. The heat resistance test results for Comparative Experiments BG are reported in Table 4.

[0274] Table 4

[0275]

[0276]

[0277] The coating composition of Comparative B had a T of 139°C. g1 The coating composition of Comparative F has a T of 135°C. g1 , and the coating composition of Comparative C has a T of 126°C g1 . Comparison of B, F and C shows that a sufficiently high T g1 It is necessary to achieve improved temperature resistance.

[0278] The coating composition of Comparative D had a T of 89°C. g2 and 95°C T g Comparative E has a T of 60°C. g2 The coating composition of Comparative G consists only of high T g phase composition, and no low T g Phase and no measurable T g2 None of these comparative examples showed any improvement in heat resistance. Comparison of D, E and G shows the surprising finding that in addition to high T g In addition to the polymer phase, there is also a low T g The polymer phase is also necessary to improve the temperature resistance of the coated substrate. As shown in Comparison D and E, low T g The phase should not be too high and should be consistent with T g1The difference is large enough T g2 .

Claims

1. A coated packaging film, comprising: (1) a heat-sealable substrate having a heat-sealable region and opposing surfaces on opposite sides of the heat-sealable region, (2) a heat-resistant coating provided on at least a portion of the opposite surface of the substrate, The heat-resistant coating comprises: (I) one or more having a glass transition temperature T of at least 140°C g1 The polymer (I), and (II) one or more having a glass transition temperature T of at most 50°C g2 The polymer (II) Where T g1 and T g2 The difference between is at least 100°C, Wherein T g1 and T g2 Determined by differential scanning calorimetry as described in the specification, and wherein the substrate is composed of at least 60 wt % of a polymer selected from polyethylene, oriented polyethylene, and any combination thereof, based on the total weight of the substrate.

2. The packaging film according to claim 1, wherein the one or more polymers have a glass transition temperature T g1 The estimated thermal mass content of the polymer (I) is at least 7.5% by weight, preferably at least 10% by weight, and the estimated thermal mass content of the one or more polymers (I) is at most 85% by weight, preferably at most 80% by weight, more preferably at most 75% by weight, even more preferably at most 70% by weight, relative to the total mass of polymers present in the heat-resistant coating, wherein the one or more polymers having T g1 The heat estimated mass content of the polymer is determined using the method described in the specification.

3. The packaging film according to claim 1, wherein the one or more polymers have a glass transition temperature T g1 The thermally estimated mass content of polymer (I) is at least 15% by weight, preferably at least 20% by weight.

4. The packaging film according to any one of the preceding claims, wherein the one or more polymers (I) have a glass transition temperature T of at least 142°C, preferably at least 145°C, more preferably at least 150°C and preferably at most 260°C, more preferably at most 250°C, more preferably at most 240°C, more preferably at most 230°C, more preferably at most 220°C. g1 .

5. The packaging film according to any one of the preceding claims, wherein the one or more polymers (I) are or are derived from a polymer comprising: one or more monomers (A1) selected from styrene, substituted styrene, acrylate, methacrylate and itaconate, and One or more monomers (A2) selected from acrylic acid, β-carboxyethyl acrylate, methacrylic acid, maleic acid, maleic anhydride and itaconic acid, preferably, the one or more monomers (A1) are selected from styrene and methacrylate, and the one or more monomers (A2) are selected from acrylic acid, methacrylic acid, maleic acid and maleic anhydride.

6. The packaging film according to any one of the preceding claims, wherein the one or more polymers (I) are or are derived from styrene / maleic anhydride (SMA) copolymers, preferably having a weight average molecular weight of 4000 to 150000 g / mol, determined by the method as described in the description and / or having an acid number of 130 to 500 mg KOH / gram of SMA.

7. The packaging film according to any one of the preceding claims, wherein T g1 and T g2 The difference between is at least 110°C, preferably at least 120°C and preferably at most 320°C, more preferably at most 295°C, more preferably at most 270°C, more preferably at most 245°C, more preferably at most 220°C.

8. The packaging film according to any one of the preceding claims, wherein T g2 It is at least -60°C, preferably at least -50°C, more preferably at least -40°C, more preferably at least -30°C, more preferably at least -25°C, and preferably at most 40°C, more preferably at most 30°C, more preferably at most 25°C.

9. The packaging film according to any one of the preceding claims, wherein The one or more polymers have a glass transition temperature T g2 The heat-estimated mass content of polymer (II) is at least 15% by weight, more preferably at least 17.5% by weight, and the one or more polymers having a glass transition temperature T g2 The polymer (II) has a thermally estimated mass content of at most 90 wt %, preferably at most 85 wt %, more preferably at most 80 wt %, wherein the one or more g2 The heat estimated mass content of the polymer is determined using the method described in the specification.

10. The packaging film according to any one of the preceding claims, wherein the one or more has a glass transition temperature T g1 The amount of polymer (I) is related to the one or more having a glass transition temperature T g2 The ratio of the amount of polymer (II) to that of is at least 1:5, more preferably at least 1:4, and preferably at most 5:1, more preferably at most 4:1, wherein the ratio is determined by the method as described in the description.

11. The packaging film according to any one of the preceding claims, wherein (i) the one or more polymers (I) have a glass transition temperature T of at least 150°C and at most 210°C g1 , (ii) the one or more polymers (I) have a thermally estimated mass content of at least 25% and at most 80% by weight relative to the total mass of polymers present in the heat-resistant coating, (iii) the one or more polymers (II) have a glass transition temperature T of at least -30°C and at most 30°C g2 , (iv) the thermally estimated mass content of the one or more polymers (II) is at least 15% by weight and at most 50% by weight, relative to the total mass of polymers present in the heat-resistant coating, (v)T g1 and T g2 The difference between is at least 120°C and at most 220°C, and (vi) the one or more materials have a glass transition temperature T g1 The amount of polymer (I) is related to the one or more having a glass transition temperature T g2 The ratio of the amount of polymer (II) is at least 1:2.5 and at most 3.25:

1.

12. The packaging film according to any one of the preceding claims, wherein the one or more has a glass transition temperature T g2 The polymer (II) comprises (B1) an ethylenically unsaturated monomer, and (B2) optionally, a carboxylic acid functional ethylenically unsaturated monomer different from (B1).

13. The packaging film according to claim 12, wherein (B1) is a combination of one or more acrylates and one or more methacrylates.

14. The packaging film according to any one of the preceding claims, wherein the one or more has a glass transition temperature T g2 The polymer has a glass transition temperature T g1 prepared in the presence of a polymer.

15. The packaging film according to claim 14, wherein T g2 It is at most 20°C, more preferably at most 15°C, more preferably at most 10°C, more preferably at most 5°C.

16. The packaging film according to any one of the preceding claims, wherein the one or more of the heat resistant coatings have a glass transition temperature T g1 Estimated heat content of the polymer by mass and the one or more having a glass transition temperature T g2 The sum of the thermally estimated mass contents of the polymers is at least 40 wt%, more preferably at least 50 wt%, relative to the total mass of the polymers present in the heat-resistant coating.

17. The packaging film according to any one of the preceding claims, wherein the substrate consists of at least 70 wt%, more preferably at least 80 wt%, based on the total weight of the substrate, of a polymer selected from polyethylene PE, oriented polyethylene and any combination thereof.

18. The packaging film according to any one of claims 1 to 16, wherein the substrate consists of at least 60 wt%, preferably at least 70 wt%, more preferably at least 80 wt% of oriented polyethylene, based on the total weight of the substrate.

19. The packaging film according to any one of claims 1 to 16, wherein the substrate consists of at least 60 wt%, preferably at least 70 wt%, more preferably at least 80 wt% of machine-direction oriented polyethylene, based on the total weight of the substrate.

20. The packaging film according to any one of claims 1 to 16, wherein the substrate consists of at least 60 wt%, preferably at least 70 wt%, more preferably at least 80 wt% of biaxially oriented polyethylene (BOPE), based on the total weight of the substrate.

21. A packaging film according to any preceding claim, wherein the heat-sealable region is formed from a polymer, preferably a polyethylene polymer.

22. The packaging film according to any one of the preceding claims, wherein the heat resistant coating has a dry thickness of at least 0.05 μm, preferably at least 0.1 μm, more preferably at least 0.25 μm, more preferably at least 0.4 μm and preferably at most 25 μm, more preferably at most 15 μm, more preferably at most 10 μm, more preferably at most 8 μm.

23. A packaging article obtained by heat sealing the coated packaging film according to any one of claims 1 to 22 to a heat-sealable substrate, which may be the same coated packaging film or another heat-sealable substrate, wherein the heat-resistant coating forms the outermost surface of the packaging article.

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