CN109161363B - High-resistance water-proof adhesive - Google Patents

Abstract

The invention relates to the field of packaging materials, in particular to a high-resistance water-proof adhesive, a method for preparing the water-based adhesive and application of the water-based adhesive. The invention also relates to a composite film comprising an adhesion barrier layer formed by the aqueous adhesive of the invention. The invention also relates to a method for preparing the composite film, to the use of the composite film and to a package comprising the composite film.

Description

High-resistance water-proof adhesive

Technical Field

The invention relates to the field of packaging materials, in particular to a high-resistance water-proof adhesive, a method for preparing the water-based adhesive and application of the water-based adhesive. The invention also relates to a composite film comprising an adhesion barrier layer formed by the aqueous adhesive of the invention. The invention also relates to a method for preparing the composite film, to the use of the composite film and to a package comprising the composite film.

Background

Although plastic packages have been widely used for food and non-food packaging materials, conventional plastic packages have poor barrier properties against gases (such as oxygen, carbon dioxide gas, aroma) or moisture. Food packaging materials require good barrier properties against oxygen because oxygen in the environment can cause food oxidation, browning, rancidity, off-flavor, mold production, and the like, which are liable to harm health. In addition, the food packaging material also needs to have certain barrier properties against carbon dioxide gas, aroma, water vapor and the like.

In order to meet the requirement of the packaging material on barrier property, a common method is to coat a high barrier material (PVA, PVDC) on a substrate, or to add a barrier material (EVOH) while processing a substrate film by adopting a multilayer co-extrusion device, so as to directly extrude the high barrier film. However, these methods easily increase the packaging cost, so that food manufacturers adopt non-barrier packaging due to the price factor of high-barrier packaging materials, which causes deterioration of food in shelf life, loss of aroma, invasion of external peculiar smell, deterioration of food taste, and great hidden danger to food safety.

In recent years, as the food industry has continued to advance, demands for packaging materials such as printing, strength, heat sealability, and appearance have been increasing. To meet these requirements, it is sometimes necessary to bond two different materials of film together. All adhesives adopted in the prior art are organic solvents, and Volatile Organic Compounds (VOC) are discharged in the processing process of packaging materials, so that great pressure is caused on environmental protection, and the environment is damaged. In addition, the adhesives used in the prior art generally do not have any other function than the bonding function.

Therefore, there is a need in the art for a new adhesive that can meet the requirements of packaging materials in terms of barrier properties, adhesion, environmental protection, processing costs, and the like.

Disclosure of Invention

The present inventors have conducted extensive studies to inventively obtain an aqueous adhesive which can impart excellent barrier properties to a packaging material and has excellent adhesive strength and good processability and workability without causing VOC emission, thereby providing the following invention:

aqueous adhesive

In one aspect, the present application provides an aqueous adhesive comprising:

(1) 1% -30% of barrier resin;

(2) 0.1% -20% of a prepolymerization agent;

(3) 0.01-20% of crosslinking curing agent;

(4) 0% -5% of nano inorganic matter;

(5) 0% -2% of heat stabilizer and/or light stabilizer;

(6) 0% -10% of leveling tackifier;

(7) 0% -2% of a surfactant; and

(8) 11% -98.89% of water;

wherein each weight percent is based on the total weight of the aqueous adhesive.

In certain embodiments, the barrier resin may be selected from: polyvinyl alcohol, polyvinyl pyrrolidone, and mixtures thereof.

In certain embodiments, the barrier resin may have a molecular weight of about 3,000 to about 300,000, for example may have a molecular weight of about 3,000 to about 10,000, about 10,000 to about 25,000, about 25,000 to about 35,000, about 35,000 to about 50,000, about 50,000 to about 100,000, about 100,000 to about 120,000, about 120,000 to about 150,000, about 150,000 to about 170,000, about 170,000 to about 220,000, about 220,000 to about 250,000, or about 250,000 to about 300,000.

In certain embodiments, the barrier resin may comprise polyvinyl alcohol. In certain embodiments, the polyvinyl alcohol may have a degree of polymerization of about 500 to about 3,000, for example, a degree of polymerization of about 500, about 1,000, about 1,500, about 1,650, about 1,700, about 1,850, about 2,000, about 2,400, or about 2,600. In certain embodiments, the polyvinyl alcohol may have a degree of hydrolysis of at least about 78%, for example may have a degree of hydrolysis of about 88%, about 95%, or about 99%. In certain embodiments, the polyvinyl alcohol may have a degree of polymerization of about 1700, and a degree of hydrolysis of about 88% to about 99%.

In certain embodiments, the barrier resin may comprise polyvinylpyrrolidone. In certain embodiments, the polyvinylpyrrolidone may have a molecular weight of about 3,000 to about 40,000, for example may have a molecular weight of about 3,500, about 5,500, about 10,100, about 32,000, or about 37,900.

In certain embodiments, the prepolymerization agent may be selected from: epoxy resins, polyurethanes, saturated polyesters, ethylene aminated acrylic polymers, polyester resins, polyethyleneimines, urea, melamine resins (melamine formaldehyde resins), polyamide epichlorohydrin resins, ammonia-epichlorohydrin resins, water-soluble alkyd resins, kemp's resins, and any combination thereof.

In the present invention, the pre-polymerization agent refers to a substance which plays a role in adhesion in the adhesive, and may be an oligomer having a plurality (e.g., 2, 3, 4 or 5) of reactive functional groups (e.g., containing epoxy, urethane, hydroxyl, amino and/or alkenyl groups, etc.), which may be at any position of the oligomer chain (e.g., may be a terminal group or a pendant group of the oligomer). In certain embodiments, the prepolymerizing agent may have a molecular weight of about 300 to about 5000, for example a molecular weight of about 300 to about 1000, about 1000 to about 2000, about 2000 to about 3000, about 3000 to about 4000, or about 4000 to about 5000.

The prepolymerizing agent of the present invention may also be a small molecule, such as urea, melamine, etc., containing multiple (e.g., 2, 3, 4, or 5) reactable functional groups (e.g., hydroxyl, amino, and/or alkenyl groups, etc.) that can form a polymer.

In certain embodiments, the crosslinking curing agent may be selected from: aliphatic carboxylic acids and their derivatives (e.g., citric acid, formic acid, acetic acid, acrylic acid, maleic acid, sorbic acid, itaconic acid, acetic anhydride, maleic anhydride), aliphatic aldehydes (e.g., formaldehyde, acetaldehyde, glyoxal, methylal, paraformaldehyde, acrolein, citral, pentanal), oxazoline polymers, isocyanates, triallyl isocyanurate, and any combination thereof.

In certain embodiments, the nano-minerals may be selected from: nano silicon oxide, nano aluminum oxide, nano titanium oxide, nano zinc oxide, nano silver oxide, graphene, nano montmorillonite, nano talcum powder, nano calcium carbonate, nano clay and any combination thereof. In certain embodiments, the nanosinorganics have an average particle size of from about 10nm to about 200nm, such as from about 10nm to about 20nm, from about 20nm to about 50nm, from about 50nm to about 100nm, or from about 100nm to about 20 nm.

In certain embodiments, the heat and light stabilizers may be independently selected from: inorganic and organic lead salt heat stabilizers, metal soap and metal salt stabilizers, organotin stabilizers, organic antimony stabilizers, rare earth stabilizers, stearic acid, salicylate-based light stabilizers, benzoate-based light stabilizers, cyanoacrylate-based light stabilizers, benzophenone-based light stabilizers, hindered amine-based light stabilizers, zinc-based light shielding agents, mixtures thereof, and any combinations thereof.

In certain embodiments, the leveling tackifier may be selected from: ethanol, methanol, isopropanol, butanol, an ethylene glycol ether, a propylene glycol ether, vinyl pyrrolidone, a polyol, cellulose, chitosan, chitin, acrylamide, caprolactam, and any combination thereof.

In certain embodiments, the surfactant may be selected from the group consisting of alkylphenol ethoxylates, dodecyldimethylammonium oxide, fluorocarbon surfactants, hydrocarbon surfactants, alkylbenzene sulfonates, and any combination thereof.

In certain embodiments, the aqueous adhesive may comprise from about 1% to about 5%, from about 5% to about 10%, from about 10% to about 15%, from about 15% to about 20%, from about 20% to about 25%, or from about 25% to about 30% of a barrier resin. In certain embodiments, the aqueous adhesive may comprise about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, or 30% barrier resin.

In certain embodiments, the aqueous adhesive may comprise from about 0.1% to about 1%, from about 1% to about 5%, from about 5% to about 10%, from about 10% to about 15%, or from about 15% to about 20% of a pre-polymerization agent. In certain embodiments, the aqueous adhesive may comprise about 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20% of a pre-polymerization agent.

In certain embodiments, the aqueous adhesive may comprise from about 0.01% to about 0.1%, from about 0.1% to about 1%, from about 1% to about 5%, from about 5% to about 10%, from about 10% to about 15%, or from about 15% to about 20% of a crosslinking curative. In certain embodiments, the aqueous adhesive may comprise about 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20% crosslinking curative.

In certain embodiments, the aqueous adhesive may comprise 0% to about 1%, about 1% to about 2%, about 2% to about 3%, about 3% to about 4%, or about 4% to about 5% of a nano-mineral. In certain embodiments, the aqueous adhesive may comprise about 0%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, or 5% of a nano-mineral.

In certain embodiments, the aqueous adhesive may comprise from 0% to about 0.5%, from about 0.5% to about 1%, from about 1% to about 1.5%, or from about 1.5% to about 2% of a heat and/or light stabilizer. In certain embodiments, the aqueous adhesive may comprise about 0%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, or 2% of a heat and/or light stabilizer.

In certain embodiments, the aqueous adhesive may comprise from 0% to about 0.1%, from about 0.1% to about 1%, from about 1% to about 5%, or from about 5% to about 10% of a leveling tackifier. In certain embodiments, the aqueous adhesive comprises about 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10% of a leveling tackifier.

In certain embodiments, the aqueous adhesive may comprise from 0% to about 0.5%, from about 0.5% to about 1%, from about 1% to about 1.5%, or from about 1.5% to about 2% of a surfactant. In certain embodiments, the aqueous adhesive may comprise about 0%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, or 2% surfactant.

In certain embodiments, the aqueous adhesive may comprise from about 11% to about 15%, from about 15% to about 20%, from about 20% to about 30%, from about 30% to about 40%, from about 40% to about 50%, from about 50% to about 60%, from about 60% to about 70%, from about 70% to about 80%, from about 80% to about 90%, or from about 90% to about 98.89% water. In certain embodiments, the aqueous adhesive may comprise about 11%, 15%, 20%, 30%, 40%, 50%, 58%, 59%, 59.69%, 60%, 63%, 64%, 64.98%, 65%, 66%, 66.8%, 67%, 70%, 71%, 71.5%, 72%, 75%, 78%, 79%, 79.4%, 80%, 81%, 82%, 82.5%, 83%, 84%, 85%, 86%, 87%, 87.5%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 98.5% or 98.89% water.

In certain embodiments, the aqueous adhesive may comprise: from about 1% to about 30% of a barrier resin, from about 0.1% to about 20% of a pre-polymerization agent, from about 0.01% to about 20% of a crosslinking curing agent, and from 11% to 98.89% of water.

In certain embodiments, the aqueous adhesive may comprise: from about 1% to about 30% of a barrier resin, from about 0.1% to about 20% of a pre-polymerization agent, from about 0.01% to about 20% of a crosslinking curing agent, from 0% to about 5% of a nano-mineral, from 0% to about 10% of a leveling tackifier, and from about 11% to about 98.89% of water.

In certain embodiments, the aqueous adhesive may comprise: from about 1% to about 30% of a barrier resin, from about 0.1% to about 20% of a pre-polymerization agent, from about 0.01% to about 20% of a crosslinking curing agent, from 0% to about 2% of a heat and/or light stabilizer, from 0% to about 2% of a surfactant, and from about 11% to about 98.89% of water.

In certain embodiments, the barrier resin may be selected from: polyvinyl alcohol, a mixture of polyvinyl alcohol and polyvinylpyrrolidone. Preferably, the weight ratio of polyvinyl alcohol to polyvinylpyrrolidone in the mixture of polyvinyl alcohol and polyvinylpyrrolidone is from about 1-5:0.5-1, for example about 1: 0.5.

In certain embodiments, the prepolymerization agent may be selected from: epoxy resins, melamine resins, saturated polyesters, polyurethanes, melamines, polyethyleneimines, polyamide epichlorohydrin resins, polyester resins, and any combination thereof. In certain embodiments, the prepolymerization agent may be selected from: mixtures of epoxy and melamine resins, saturated polyesters, polyurethanes, melamines, polyethyleneimines, polyamide epichlorohydrin resins, polyester resins. Preferably, the weight ratio of epoxy resin to melamine resin in the mixture of epoxy resin and melamine resin may be from about 0.1 to 1:1 to 5, for example about 0.3: 1.

In certain embodiments, the crosslinking curing agent may be selected from: citric acid, glyoxal, oxazoline polymers, formaldehyde, formic acid, isocyanate, maleic anhydride, and any combination thereof.

In certain embodiments, the nano-inorganics may be nano-alumina.

In certain embodiments, the heat or light stabilizer may be a rare earth stabilizer.

In certain embodiments, the leveling tackifier may be ethanol.

In certain embodiments, the surfactant may be a hydrocarbon surfactant.

In certain embodiments, the aqueous adhesives of the present invention may comprise: polyvinyl alcohol, epoxy resin, melamine resin, citric acid and water. In certain embodiments, the aqueous adhesive may comprise: from about 9% to about 11% polyvinyl alcohol, from about 1% to about 2% of a mixture of epoxy resin and melamine resin, from 0.1% to 1% citric acid, and water.

In certain embodiments, the aqueous adhesives of the present invention may comprise: polyvinyl alcohol, saturated polyester, glyoxal and water. In certain embodiments, the aqueous adhesive comprises: from about 20% to about 30% polyvinyl alcohol, from about 8% to about 11% saturated polyester, from about 3% to about 5% glyoxal, and water.

In certain embodiments, the aqueous adhesives of the present invention may comprise: polyvinyl alcohol, polyvinylpyrrolidone, polyurethane, oxazoline polymers and water. In certain embodiments, the aqueous adhesive may comprise: from about 20% to about 30% of a mixture of polyvinyl alcohol and polyvinylpyrrolidone, from about 8% to about 11% of a polyurethane, from about 0.01% to about 0.1% of an oxazoline polymer, and water.

In certain embodiments, the aqueous adhesives of the present invention may comprise: polyvinyl alcohol, melamine, formaldehyde and water. In certain embodiments, the aqueous adhesive may comprise: about 20% to about 30% polyvinyl alcohol, about 5% to about 10% melamine, about 0.1% to about 1% formaldehyde, and water.

In certain embodiments, the aqueous adhesives of the present invention may comprise: polyvinyl alcohol, polyethyleneimine, nano-alumina, ethanol, formic acid and water. In certain embodiments, the aqueous adhesive may comprise: about 12% to about 15% polyvinyl alcohol, about 0.1% to about 0.5% polyethyleneimine, about 1% to about 5% nano alumina, about 8% to about 10% ethanol, about 4% to about 6% formic acid, and water.

In certain embodiments, the aqueous adhesives of the present invention may comprise: polyvinyl alcohol, polyamide epichlorohydrin resin, rare earth stabilizer, hydrocarbon surfactant, isocyanate and water. In certain embodiments, the aqueous adhesive may comprise: from about 18% to about 20% polyvinyl alcohol, from about 5% to about 10% polyamide epichlorohydrin resin, from about 0.1% to about 0.5% rare earth stabilizer, from about 0.01% to about 0.05% hydrocarbon surfactant, from about 10% to about 16% isocyanate, and water.

In certain embodiments, the aqueous adhesives of the present invention may comprise: polyvinyl alcohol, polyurethane, oxazoline polymers, rare earth stabilizers, hydrocarbon surfactants and water. In certain embodiments, the aqueous adhesive may comprise: from about 10% to about 15% polyvinyl alcohol, from about 3% to about 5% polyurethane, from about 1% to about 3% oxazoline polymer, from about 0.1% to about 0.5% of a mixture of a rare earth stabilizer and a hydrocarbon surfactant, and water. Wherein, the ratio of the rare earth stabilizer and the hydrocarbon surfactant can be adjusted according to actual needs, for example, the ratio of the rare earth stabilizer to the hydrocarbon surfactant can be about 1:0.5 to about 1: 1.

In certain embodiments, the aqueous adhesives of the present invention may comprise: polyvinyl alcohol, polyester resin, a rare earth stabilizer, a hydrocarbon surfactant, maleic anhydride and water. In certain embodiments, the aqueous adhesive may comprise: from about 10% to about 15% polyvinyl alcohol, from about 3% to about 5% polyester resin, from about 0.1% to about 0.5% rare earth stabilizer, from about 0.1% to about 0.5% hydrocarbon surfactant, from about 0.1% to about 0.5% maleic anhydride, and water.

The aqueous adhesives of the present invention may be obtained using commercially available raw materials, and alternative commercially available raw materials include, but are not limited to: polyvinyl alcohol-1799, polyvinyl alcohol-1788, epoxy resin CYD803, melamine resin DY104, saturated polyester BPE-9985, polyvinylpyrrolidone K17, polyurethane 58887, polyurethane X-PU632, oxazoline polymer 500, polyethyleneimine SP-003, nano alumina C1-L20M, polyamide epichlorohydrin resin 1200S3, rare earth stabilizer XT-1, rare earth stabilizer XT-2, rare earth stabilizer XT-3, hydrocarbon surfactant 2223, hydrocarbon surfactant 343, hydrocarbon surfactant 434, isocyanate 44V20 and polyester resin 51530.

The aqueous adhesive of the present invention may further contain an antioxidant, a defoaming agent, a colorant, and the like, as required.

Composite membrane

The aqueous adhesive can be used for compounding various packaging substrates, such as compounding of a polymer film and a polymer film or compounding of a polymer film and paper, and can simultaneously realize double functions of adhesion and barrier.

Accordingly, the present application provides a composite film comprising an adhesion barrier layer formed from the aqueous adhesive of the present invention.

In certain embodiments, the composite film may comprise, in order, a first substrate layer, which may consist essentially of a polymer or paper, the bond barrier layer, and a second substrate layer, which may consist essentially of a polymer or paper.

In the composite film of the present invention, the material of the base material layer is not particularly limited, and preferably, at least one of the first base material layer and the second base material layer may be composed mainly of a polymer.

In certain embodiments, the polymer in the first substrate layer and the polymer in the second substrate layer independently may be selected from Polyethylene (PE), polypropylene (PP), Polyamide (PA), polyethylene terephthalate (PET), and Polystyrene (PS).

In certain embodiments, the polyethylene may be selected from: linear Low Density Polyethylene (LLDPE), Low Density Polyethylene (LDPE), Medium Density Polyethylene (MDPE) and High Density Polyethylene (HDPE).

In certain embodiments, the primary component of the first and second substrate layers may be selected from the group consisting of:

(1) polyethylene and polyethylene;

(2) polypropylene and polypropylene;

(3) nylon and polypropylene;

(4) polyethylene terephthalate and polyethylene;

(5) polyethylene terephthalate and polypropylene;

(6) polypropylene and polyethylene;

(7) nylon and polyethylene;

(8) paper and polyethylene;

(9) paper and polypropylene;

(10) polystyrene and polypropylene.

When a certain combination of the above is used as the main component of the first substrate layer and the second substrate layer, the first substrate layer may be any member of the combination, and the second substrate layer is another member of the combination.

For example, when the combination (1) is used, the main component of the first substrate layer is polyethylene, and in this case, the main component of the second substrate layer is polyethylene having the same or different properties as the polyethylene of the first substrate layer.

For example, when the combination (2) is used, the main component of the first substrate layer is polypropylene, in which case the main component of the second substrate layer is polypropylene having the same or different properties as the polypropylene of the first substrate layer,

for example, when the combination of (3) is used, the main component of the first base material layer may be nylon (in this case, the main component of the second base material layer is polypropylene), or may be polypropylene (in this case, the main component of the second base material layer is nylon).

For example, when the combination (4) is used, the main component of the first substrate layer may be polyethylene terephthalate (in this case, the main component of the second substrate layer is polyethylene), or may be polyethylene (in this case, the main component of the second substrate layer is polyethylene terephthalate).

For example, when the combination (5) is used, the main component of the first substrate layer may be polyethylene terephthalate (in this case, the main component of the second substrate layer is polypropylene), or may be polypropylene (in this case, the main component of the second substrate layer is polyethylene terephthalate).

For example, when the combination (6) is used, the main component of the first substrate layer may be polypropylene (in this case, the main component of the second substrate layer is polyethylene), or may be polyethylene (in this case, the main component of the second substrate layer is polypropylene).

For example, when the combination (7) is used, the main component of the first substrate layer may be nylon (in this case, the main component of the second substrate layer is polyethylene), or may be polyethylene (in this case, the main component of the second substrate layer is nylon).

For example, when the combination (8) is used, the main component of the first base material layer may be paper (in which case the main component of the second base material layer is polyethylene), or may be polyethylene (in which case the main component of the second base material layer is paper).

For example, when the combination (9) is used, the main component of the first base material layer may be paper (in this case, the main component of the second base material layer is polypropylene), or may be polypropylene (in this case, the main component of the second base material layer is paper).

For example, when the (10) th combination is used, the main component of the first base material layer may be polystyrene (in this case, the main component of the second base material layer is polypropylene), or may be polypropylene (in this case, the main component of the second base material layer is polystyrene).

In the composite film of the present invention, the first base material layer and the second base material layer may be bonded together by the adhesion barrier layer. In certain embodiments, the adhesive barrier layer may be formed by coating an aqueous adhesive as described in any of the above.

In the composite film of the present invention, the thickness of each layer is not particularly limited. In certain embodiments, the bond barrier layer may have a thickness of about 2 μm to about 6 μm, which facilitates drying of the aqueous adhesive.

The total thickness of the composite film of the present invention is also not particularly limited. In certain embodiments, the total thickness of the composite membrane may be from about 30 μm to about 150 μm, such as from about 30 μm to about 40 μm, from about 40 μm to about 50 μm, from about 50 μm to about 60 μm, from about 60 μm to about 70 μm, from about 70 μm to about 80 μm, from about 80 μm to about 90 μm, from about 90 μm to about 100 μm, from about 100 μm to about 110 μm, from about 110 μm to about 120 μm, from about 120 μm to about 130 μm, from about 130 μm to about 140 μm, or from about 140 μm to about 150 μm.

The composite film has good peel strength. In certain embodiments, the peel strength of the composite film may be from about 1.5N to about 3N, for example from about 1.5N to about 1.6N, from about 1.6N to about 1.7N, from about 1.7N to about 1.8N, from about 1.8N to about 1.9N, from about 1.9N to about 2.0N, from about 2.0N to about 2.1N, from about 2.1N to about 2.2N, from about 2.2N to about 2.3N, from about 2.3N to about 2.4N, from about 2.4N to about 2.5N, from about 2.5N to about 2.6N, from about 2.6N to about 2.7N, from about 2.7N to about 2.8N, from about 2.8N to about 2.9N, or from about 2.9N to about 3.0N, measured according to the methods of national standard GB 8808.

Meanwhile, the composite membrane has good gas barrier property. In certain embodiments, the oxygen transmission capacity of the composite membrane may be from about 0.2 to about 2.5cm, for example as measured according to the national standard GB/T1038-³/m²24 h.1 MPa, e.g. about 0.2 to about 0.5cm³/m²24 h.1 MPa, about 0.5 to about 1cm³/m²24 h.1 MPa, about 1 to about 1.5cm³/m²24 h.1 MPa, about 1.5 to about 2cm³/m²24 h.1 MPa or from about 2 to about 2.5cm³/m²24 h.1 MPa, e.g. about 0.2cm³/m²·24h·1MPa、0.3cm³/m²·24h·1MPa、0.4cm³/m²·24h·1MPa、0.5cm³/m²·24h·1MPa、0.6cm³/m²·24h·1MPa、0.7cm³/m²·24h·1MPa、0.8cm³/m²·24h·1MPa、0.9cm³/m²·24h·1MPa、1.0cm³/m²·24h·1MPa、1.1cm³/m²·24h·1MPa、1.2cm³/m²·24h·1MPa、1.3cm³/m²·24h·1MPa、1.4cm³/m²·24h·1MPa、1.5cm³/m²·24h·1MPa、1.6cm³/m²·24h·1MPa、1.7cm³/m²·24h·1MPa、1.8cm³/m²·24h·1MPa、1.9cm³/m²·24h·1MPa、2.0cm³/m²·24h·1MPa、2.1cm³/m²·24h·1MPa、2.2cm³/m²·24h·1MPa、2.3cm³/m²·24h·1MPa、2.4cm³/m²24 h.1 MPa or 2.5cm³/m²24 h.1 MPa (test pressure difference of 1MPa, temperature of 23 ℃ and humidity of 65%).

In certain embodiments, such as where both the first and second substrate layers are composed primarily of polymers, the composite film may have good transparency, such as good light transmittance and low haze.

The composite films of the present invention are particularly suitable for use in the packaging field. In certain embodiments, the composite film may be a packaging film, the first substrate layer may be a protective layer, and the second substrate layer may be a sealant layer.

In certain embodiments, the protective layer may consist essentially of polyamide, polypropylene, or polyethylene terephthalate.

In certain embodiments, the sealing layer may consist essentially of polyethylene or polypropylene.

In certain embodiments, the principal components of the protective and sealing layers may be a combination selected from:

(1) the main component of the protective layer is PP, and the main component of the sealing layer is PE;

(2) the main component of the protective layer is PA, and the main component of the sealing layer is PE;

(3) the main component of the protective layer is PP, and the main component of the sealing layer is PP;

(4) the main component of the protective layer is PET, and the main component of the sealing layer is PE;

(5) the main component of the protective layer is PA, and the main component of the sealing layer is PP.

In certain embodiments, the composite film of the present invention may also comprise other layers, such as a print layer, and may also be provided with additional adhesive layers or additional barrier layers to further improve the adhesive strength or barrier properties.

In certain embodiments, the composite membranes of the present invention may be made by the process for making the composite membranes described below.

Method for preparing composite membrane

The aqueous adhesive of the present invention can be used to prepare a composite film by a method such as dry lamination. In the dry compounding, firstly, an adhesive is coated on one base material, then a solvent in the adhesive is dried, then the other base material is attached to the base material, and then the curing treatment is carried out, so as to obtain the composite film.

Thus, in certain embodiments, the method may comprise the steps of:

step 1: providing a first substrate, a second substrate and the aqueous adhesive of the invention;

step 2: coating the surface of the first substrate with the aqueous adhesive of the invention;

and step 3: heating the coated first substrate;

and 4, step 4: under the conditions of heating and pressurizing, the second base material is attached to the first base material treated in the step 3 to obtain a semi-finished film;

and 5: and (4) curing the semi-finished film obtained in the step (4).

Preferably, the first substrate and the second substrate may each independently be selected from the group consisting of polymeric films and papers.

In the method of producing a composite film of the present invention, there is no particular limitation in the selection of the substrate, but preferably, at least one of the first substrate and the second substrate is a polymer film.

In certain embodiments, the polymeric film may be selected from the group consisting of polyethylene film (PE film), polypropylene film (PP film), polyamide film (PA film), polyethylene terephthalate film (PET film), and polystyrene film (PS film).

In certain embodiments, the polypropylene film may be selected from: oriented polypropylene films (OPP films), biaxially oriented polypropylene films (BOPP films), and cast polypropylene films (CPP films).

In certain embodiments, the polyethylene film may be selected from: linear low density polyethylene film (LLDPE film), low density polyethylene film (LDPE film), medium density polyethylene film (MDPE film), high density polyethylene film (HDPE film).

In certain embodiments, the first substrate and the second substrate may be a combination selected from the group consisting of:

(1) polyethylene films and polyethylene films (PE film/PE film);

(2) polypropylene films and polypropylene films, such as oriented polypropylene films and cast polypropylene films (OPP film/CPP film);

(3) nylon and polypropylene films (PA/PP films);

(4) polyethylene terephthalate film and polyethylene film (PET film/PE film);

(5) polyethylene terephthalate films and polypropylene films, such as polyethylene terephthalate films and cast polypropylene films (PET films/CPP films);

(6) polypropylene and polyethylene films, such as oriented polypropylene and polyethylene films (OPP/PE films);

(7) nylon and polyethylene films (PA/PE films);

(8) paper and polyethylene film;

(9) paper and polypropylene films;

(10) polystyrene films and polypropylene films.

When a combination of the above is used as the first substrate and the second substrate, the first substrate can be any member of the combination and the second substrate is another member of the combination.

For example, when combination (1) is used, the first substrate is a polyethylene film, in which case the second substrate is another polyethylene film of the same or different properties as the polyethylene film used as the first substrate.

For example, when combination (2) is used, the first substrate is a polypropylene film, in which case the second substrate is another polypropylene film having the same or different properties as the polypropylene film used as the first substrate.

For example, when the combination of (3) is used, the first substrate may be a nylon film (in which case the second substrate is a polypropylene film), or may be a polypropylene film (in which case the second substrate is a nylon film).

For example, when the combination of (4) is used, the first substrate may be a polyethylene terephthalate film (in which case the second substrate is a polyethylene film), or may be a polyethylene film (in which case the second substrate is a polyethylene terephthalate film).

For example, when the combination of (5) is used, the first substrate may be a polyethylene terephthalate film (in which case the second substrate is a polypropylene film), or may be a polypropylene film (in which case the second substrate is a polyethylene terephthalate film).

For example, when combination (6) is used, the first substrate may be a polypropylene film (in which case the second substrate is a polyethylene film), or may be a polyethylene film (in which case the second substrate is a polypropylene film).

For example, when the combination of (7) is used, the first substrate may be a nylon film (in which case the second substrate is a polyethylene film), or may be a polyethylene film (in which case the second substrate is a nylon film).

For example, when combination (8) is used, the first substrate may be paper (in which case the second substrate is a polyethylene film), or may be a polyethylene film (in which case the second substrate is paper).

For example, when combination (9) is used, the first substrate may be paper (in which case the second substrate is a polypropylene film), or may be a polypropylene film (in which case the second substrate is paper).

For example, when the combination (10) is used, the first substrate may be a polystyrene film (in which case the second substrate is a polypropylene film), or may be a polypropylene film (in which case the second substrate is a polystyrene film).

The process of the present invention is particularly suitable for the production of packaging films having a sealing layer and a protective layer. In certain embodiments, the first substrate has good dimensional stability and can be used to form a protective layer, and the second substrate has good chemical inertness, permeation resistance, and heat sealability and can be used to form a sealing layer.

In certain embodiments, the first substrate may be selected from: polyamide films (e.g. BOPA films), polypropylene films (e.g. BOPP films), polyethylene terephthalate films.

In certain embodiments, the second substrate may be selected from: polyethylene films, polypropylene films (e.g., CPP films).

In certain embodiments, the first substrate and the second substrate may be a combination selected from the group consisting of:

(1) the first base material is a BOPP film, and the second base material is a PE film;

(2) the first base material is a BOPA film, and the second base material is a PE film;

(3) the first base material is a BOPP film, and the second base material is a CPP film;

(4) the first base material is a PET film, and the second base material is a PE film;

(5) the first substrate is a BOPA film and the second substrate is a CPP film.

The thickness of the substrate may be selected as needed, and is not particularly limited.

In certain embodiments, the first substrate can have a thickness of from about 10 μm to about 250 μm, for example from about 10 μm to about 50 μm, from about 50 μm to about 100 μm, from about 100 μm to about 150 μm, from about 150 μm to about 200 μm, or from about 200 μm to about 250 μm, such as from about 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, 210 μm, 220 μm, 230 μm, 240 μm, or 250 μm.

In certain embodiments, the thickness of the second substrate can be from about 10 μm to about 250 μm, for example from about 10 μm to about 50 μm, from about 50 μm to about 100 μm, from about 100 μm to about 150 μm, from about 150 μm to about 200 μm, or from about 200 μm to about 250 μm, such as about 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, 210 μm, 220 μm, 230 μm, 240 μm, or 250 μm.

In order to enable the substrate to be uniformly impregnated with the adhesive, the film as the substrate preferably has an appropriate surface tension. Preferably, the surface tension coefficients of the first substrate and the second substrate may be about 38 dynes or more, respectively. In the case where the surface tension of the substrate is not high, it is preferable to treat the substrate to roughen the surface thereof, so that when the adhesive is in contact with the surface of the substrate, a good wetting effect can be produced, increasing the adhesion fastness.

In certain embodiments, in step 2, the aqueous adhesive may be coated on the first substrate in an amount (dry weight) of from about 0.3 grams per square meter to about 8 grams per square meter, such as from about 0.3 grams per square meter to about 1 gram per square meter, from about 1 gram per square meter to about 5 grams per square meter, from about 5 grams per square meter to about 8 grams per square meter, such as 2 grams per square meter, 3 grams per square meter, 4 grams per square meter, 5 grams per square meter, 6 grams per square meter, 7 grams per square meter, or 8 grams per square meter.

In certain embodiments, one or more coats may be performed.

In step 3, the gummed first substrate may be heated to remove the solvent in the adhesive. In certain embodiments, the heating in step 3 may be performed in three stages, and the temperatures may in turn be from about 60 ℃ to about 75 ℃, from about 65 ℃ to about 75 ℃, from about 70 ℃ to about 85 ℃. In certain embodiments, the heating in step 3 is carried out in four stages at temperatures ranging sequentially from about 60 ℃ to about 70 ℃, from about 70 ℃ to about 75 ℃, from about 75 ℃ to about 80 ℃, and from about 75 ℃ to about 85 ℃.

In certain embodiments, the temperature of the heating in step 4 may be from about 50 ℃ to about 65 ℃, e.g., about 50 ℃, 55 ℃,60 ℃, or 60 ℃.

In step 5, the semi-finished film may be left under heating for a period of time to cure to accelerate the curing reaction in the adhesive. In certain embodiments, the temperature of the aging can be from about 40 to about 80 ℃, e.g., about 40 ℃, 45 ℃,50 ℃,60 ℃,65 ℃,70 ℃, or 80 ℃. In certain embodiments, the time for maturation may be from about 12 to about 72 hours, such as about 24 hours, 48 hours, 50 hours, or 72 hours.

The aqueous adhesive of the present invention may be used only as a barrier coating liquid, and the aqueous adhesive is coated on a substrate to form a barrier layer, and then compounded with other substrates using a solvent-free composite adhesive or a solvent-based composite adhesive as an adhesive. Thus, in certain embodiments, step 3 and step 4 may further comprise between: and (3) coating the first substrate treated in the step 3 with an additional adhesive. The additional adhesive may be a solvent-free adhesive or a solvent-borne adhesive.

The preparation can be carried out using a dry compound machine. An exemplary dry compound machine may be comprised of the following: the device comprises a main unreeling part, a gluing part (comprising components such as an anilox roller, a rubber pressing roller, a scraper, a leveling roller and the like), a drying channel or an oven, an auxiliary unreeling part, a compounding part (comprising components such as a preheating roller, a compounding hot roller, a cooling roller and the like), a cooling part and a curing chamber. An exemplary preparation process may be as follows: placing a first base material on a main unreeling machine on a dry compound machine, and coating a water-based adhesive on the first base material; drying after gluing; placing a second substrate on the auxiliary unwinding roll, and attaching the second substrate and the first substrate subjected to gluing and drying under the action of the composite hot roller to obtain a semi-finished film; and (4) putting the semi-finished film into a curing chamber for curing to obtain the composite film. The base material on the main unreeling device preferably has certain tensile strength and small deformation under certain tension and certain heating temperature.

The invention also relates to a composite membrane prepared by the method.

Method for preparing aqueous adhesive

In another aspect, the present application provides a method of preparing the aqueous adhesive as described above, which may comprise the steps of:

step 1: providing the barrier resin, a pre-polymerization agent, a crosslinking curing agent and water in proportion;

step 2: dissolving the barrier resin in water to obtain a semi-finished product;

and step 3: mixing the pre-polymerization agent and the semi-finished product, and optionally adding a nano inorganic substance, a heat stabilizer, a light stabilizer, a leveling tackifier, a surfactant or any combination thereof into the mixture of the pre-polymerization agent and the semi-finished product to obtain a water-based adhesive main agent;

and 4, step 4: and mixing the water-based adhesive main agent with a crosslinking curing agent to obtain the water-based adhesive.

Preferably, the dissolving process in step 2 may be performed under heating and stirring conditions. In certain embodiments, the temperature of heating can be from about 40 ℃ to about 90 ℃ (e.g., from about 40 ℃ to about 50 ℃, from about 50 ℃ to about 60 ℃, from about 60 ℃ to about 70 ℃, from about 70 ℃ to about 80 ℃, from about 85 ℃, or from about 80 ℃ to about 90 ℃). In certain embodiments, the heating may be for about 12 hours to about 24 hours. After dissolution of the barrier resin is completed under heating, the temperature of the semi-finished product may preferably be reduced, for example to ambient temperature, for example to about 35 ℃ to about 10 ℃, about 20 ℃ to about 10 ℃, or about 30 ℃ to about 20 ℃.

Preferably, the mixing process in step 3 may be performed under heating and stirring conditions. In certain embodiments, the temperature of heating can be from about 10 ℃ to about 70 ℃ (e.g., from about 20 ℃ to about 40 ℃, from about 40 ℃ to about 45 ℃, from about 50 ℃ to about 70 ℃, or from about 40 ℃ to about 60 ℃). In certain embodiments, the heating may be for about 1 hour to about 20 hours. Preferably, the mixture of heated prepolymerizing agent and semifinished product may be cooled, for example to ambient temperature, for example to about 25 ℃ to about 15 ℃, about 15 ℃ to about 10 ℃ or about 29 ℃ to about 20 ℃.

In certain embodiments, the step 3 further comprises: the mixture of prepolymerized agent and semifinished product is filtered to remove impurities.

According to the requirement, nano inorganic matter, heat stabilizer, light stabilizer, leveling tackifier, surfactant and the like can be added into the mixture of the prepolymerization agent and the semi-finished product. A suitable time for adding these substances may be after cooling down and may be before filtration.

The aqueous adhesive main agent of the invention has good stability, and does not generate gel phenomenon after being stored for 30 to 70 days at the temperature of about 5 to about 40 ℃.

In step 4, the barrier resin and the pre-polymerization agent in the aqueous adhesive main agent can be cured by adding the crosslinking curing agent. Therefore, the aqueous adhesive main agent is usually stored separately from the crosslinking curing agent, and the crosslinking curing agent is added before the aqueous adhesive is used. Therefore, step 4 is preferably performed before the aqueous adhesive is used. Preferably, the mixing process in step 4 may be performed under stirring.

The invention also relates to the use of the aqueous adhesive according to any one of the preceding claims for producing composite films.

The invention also relates to the use of a composite film according to any of the above for packaging articles. In certain embodiments, the article may be a food product (e.g., a liquid food product or a solid food product). In certain embodiments, the article may be a non-food product (e.g., a pharmaceutical product).

The invention also relates to a package comprising a composite film according to any of the above.

In the present invention, unless otherwise specified, scientific and technical terms used herein have the meanings that are commonly understood by those skilled in the art. Also, the laboratory procedures referred to herein are all conventional procedures widely used in the corresponding field. Meanwhile, in order to better understand the present invention, the definitions and explanations of related terms are provided below.

In the present invention, the term "film" also referred to as "thin film" refers to a thin and soft sheet made of a polymer, having a thickness of from about 1 to several hundred micrometers (e.g., from about 1 to about 250 micrometers), and includes a metal-plated film (e.g., an aluminum-plated film) formed by plating a metal (e.g., aluminum) on a polymer film by evaporation or the like.

In the present invention, the term "composite film" refers to a multilayer film formed by bonding, coextrusion, or the like, a polymer film to paper, a metal sheet (e.g., aluminum foil), or a polymer film. The material used to form the composite film is referred to as the substrate. The compounding method includes but is not limited to dry compounding, wet compounding, extrusion compounding, co-extrusion compounding and solvent-free compounding.

Composite films used for packaging are referred to as packaging films or packaging composite films. Packaging films typically comprise a sealing layer, a functional layer, and a protective layer. Wherein, the sealing layer is also called as an inner layer, usually directly contacts with the packaged object, and generally selects a material with better permeability resistance and heat sealing performance to prevent the packaged object from seeping out and facilitate the sealing of the packaging film by means of heat sealing and the like; the functional layer plays a role in blocking gas or shading light; the protective layer is also called as an outer layer, plays roles of supporting, shading and the like, and is usually made of a material with good mechanical strength, heat resistance and printing performance.

In the present invention, a layer of the composite film "consisting essentially of … …" or "consisting essentially of … …" means that the content of the unspecified component does not significantly or substantially affect the properties of the layer in question itself.

In the present invention, the barrier property of the film refers to the ability to shield small molecule gases (e.g., oxygen), liquids, water vapor or odors. The gas barrier properties of a membrane can be measured by the gas permeability, i.e., the volume of gas that permeates a unit area of the membrane per unit time at a constant temperature and pressure difference per unit time at which the gas permeates stably.

In the present invention, the term "oligomer" refers to a polymer composed of a small number (e.g., 10 to 20) of repeating units, the relative molecular mass of which is between that of a small molecule and a large molecule.

In the present invention, the term "about" should be understood by those skilled in the art and will vary to some extent depending on the context in which it is used. If the use of the term is not clear to one of ordinary skill in the art based on the context in which the term is used, then "about" means no more than plus or minus 10% of the stated particular value or range.

Advantageous effects of the invention

The water-based adhesive is used for preparing the composite film, can realize high bonding strength and good barrier property, has very good processability and operability, greatly reduces the cost of a high-barrier packaging material, and does not cause VOC emission.

Compared with the existing barrier material, the composite film prepared by the water-based adhesive has more excellent oxygen barrier property. For example, the oxygen barrier property of the composite film of the present invention is doubled as compared with an ethylene-vinyl alcohol copolymer film (EVOH film), and the cost is one tenth of that of the EVOH film.

Therefore, the water-based adhesive and the composite film can endow the packaging material with excellent barrier property, are favorable for reducing the cost of the high-barrier packaging material, and meet the requirements of various foods and non-foods on the high-barrier packaging material.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to examples, but those skilled in the art will appreciate that the following examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.

In the following examples, all parts and percentages are by weight; the oxygen transmission capacity is tested according to GB/T1038-; the composite strength refers to the peel strength of the composite film and is tested according to GB 8808.

Example 1

According to the following proportion, polyvinyl alcohol-1799 and water are added into a heatable reaction vessel and heated to 80-90 ℃ under stirring for complete dissolution. After the temperature is reduced to 35-10 ℃, adding a mixture (0.3:1 by weight) of epoxy resin and melamine resin, fully stirring and mixing, heating to 40-45 ℃, keeping the temperature and reacting for 8 hours, then reducing to normal temperature (25-15 ℃), and filtering to obtain the high-resistance waterproof adhesive main agent, wherein the main agent does not generate a gel phenomenon after being stored for 70 days at 10-40 ℃, and has good storage stability. Adding citric acid before use, and stirring to obtain the high-resistance water-resisting adhesive.

The BOPP film and the PE film are compounded by using the prepared high-resistance waterproof adhesive, and the process is as follows: on a dry compounding machine, a BOPP film with the thickness of 20 mu m is placed on a main unreeling machine, and a high-resistance water-proof adhesive is coated on the BOPP film, wherein the coating amount is 3 g per square meter. Drying after gluing, wherein the oven temperature of the compound machine is 60 ℃,70 ℃, 75 ℃ and 75 ℃ respectively. And placing a PE film with the thickness of 50 mu m on the auxiliary unwinding roll, and attaching the PE film and the BOPP film subjected to gluing and drying under the action of a composite hot roll to obtain a semi-finished film. The temperature of the composite hot roller is 60 ℃, and the machine speed is 100 meters per minute. And placing the obtained semi-finished film into a curing chamber with the temperature of 60 ℃, and curing for 48 hours to obtain the composite film.

The composite strength of the composite film was measured to be 3N, and the oxygen transmission was measured to be 1.5cm³/m²·24h·1MPa。

Example 2

According to the following proportion, polyvinyl alcohol-1788 and water are added into a heatable reaction vessel and heated to 60-70 ℃ under stirring to be completely dissolved. After the temperature is reduced to 20-10 ℃, saturated polyester is added, the mixture is fully stirred and mixed, the mixture is heated to 50-70 ℃, the temperature is kept for reaction for 12 hours, then the mixture is reduced to normal temperature (15-10 ℃), and the high-resistance waterproof adhesive main agent is obtained after filtration, and the main agent does not generate a gel phenomenon after being stored for 70 days at 10-40 ℃, and has good storage stability. Adding glyoxal and fully stirring before use to obtain the high-resistance water-resisting adhesive.

The BOPA film and the PE film are compounded by using the prepared high-resistance waterproof adhesive, and the process is as follows: on a dry compounding machine, a BOPA film with the thickness of 15 mu m is placed on a main unreeling machine, and a high-resistance water-proof adhesive is coated on the BOPA film, wherein the coating amount is 8 g per square meter. Drying after gluing, wherein the oven temperature of the compound machine is 70 ℃,70 ℃ and 70 ℃. And placing a PE film with the thickness of 120 mu m on the auxiliary unwinding roll, and attaching the PE film and the BOPA film subjected to gluing and drying under the action of a composite hot roll to obtain a semi-finished film. The temperature of the composite hot roller is 65 ℃ and the machine speed is 90 meters per minute. And placing the obtained semi-finished film into a curing chamber with the temperature of 45 ℃, and curing for 72 hours to obtain the composite film.

The composite strength of the composite film was measured to be 2.5N, and the oxygen transmission capacity was measured to be 2cm³/m²·24h·1MPa。

Example 3

According to the following proportion, a mixture of polyvinyl alcohol and polyvinylpyrrolidone (1:0.5 weight ratio) and water are added into a heatable reaction vessel and heated to 80 ℃ to 90 ℃ under stirring for complete dissolution. After the temperature is reduced to 30-20 ℃, polyurethane is added, the mixture is fully stirred and mixed, heated to 45 ℃, and then the mixture is subjected to heat preservation reaction for 7 hours, then the temperature is reduced to normal temperature (29-20 ℃), and the water-based adhesive main agent is obtained after filtration, and the main agent does not generate a gel phenomenon after being stored for 30 days at 10-30 ℃, and has good storage stability. The oxazoline polymer is added before use and fully stirred to obtain the water-based adhesive.

The BOPP film and the CPP film are compounded by using the prepared high-resistance waterproof adhesive, and the process is as follows: on a dry compounding machine, a BOPP film with the thickness of 15 mu m is placed on a main unreeling machine, and a high-resistance water-proof adhesive is coated on the BOPP film, wherein the coating amount is 5 g per square meter. Drying after gluing, wherein the oven temperature of the compound machine is 60 ℃, 75 ℃ and 80 ℃. And placing a CPP film with the thickness of 40 mu m in the auxiliary unwinding roll, and attaching the CPP film and the BOPP film subjected to gluing and drying under the action of a composite hot roll to obtain a semi-finished film. The temperature of the composite hot roll is 50 ℃, and the machine speed is 130 meters per minute. And (3) putting the semi-finished film into a curing chamber with the temperature of 65 ℃, and curing for 50 hours to obtain the composite film.

The composite strength of the composite membrane is measured to be 2N, and the oxygen transmission capacity is measured to be 1cm³/m²·24h·1MPa。

Example 4

Polyvinyl alcohol-1799 and water were added to a heatable reaction vessel and heated to 85 ℃ with stirring to dissolve completely. After the temperature is reduced to 20 ℃, melamine is added, the mixture is fully stirred and mixed, heated to 40 ℃, and then the mixture is subjected to heat preservation reaction for 7 hours, and then the mixture is reduced to the normal temperature (15 ℃) to obtain the main agent of the high-resistance waterproof adhesive after filtration, and the main agent does not generate a gel phenomenon after being stored for 60 days at the temperature of 5-40 ℃, and has good storage stability. Adding formaldehyde before use, and fully stirring to obtain the high-resistance waterproof adhesive.

Compounding the PET film and the PE film by using the prepared high-resistance waterproof adhesive, wherein the process comprises the following steps: on a dry compounding machine, a PET film with the thickness of 12 mu m is placed on a main unreeling machine, and a high-resistance water-proof adhesive is coated on the PET film, wherein the coating amount is 0.3 g per square meter. Drying after gluing, wherein the oven temperature of the compound machine is 70 ℃, 75 ℃ and 75 ℃ respectively. And placing a PE film with the thickness of 60 mu m on the auxiliary unwinding roll, and attaching the PE film and the PET film subjected to gluing and drying under the action of a composite hot roll to obtain a semi-finished film. The temperature of the composite hot roll is 50 ℃, and the machine speed is 150 meters per minute. And (3) putting the semi-finished film into a curing chamber with the temperature of 45 ℃, and curing for 48 hours to obtain the composite film.

The composite strength of the composite film was measured to be 2.5N, and the oxygen transmission was measured to be 1.3cm³/m²·24h·1MPa。

Example 5

Polyvinyl alcohol-1799 and water were added to a heatable reaction vessel and heated to 80 ℃ with stirring to dissolve completely, according to the following formulation. After the temperature is reduced to 20 ℃, polyethyleneimine is added, the mixture is fully stirred and mixed, heated to 60 ℃, and then is subjected to heat preservation reaction for 20 hours, then the temperature is reduced to normal temperature (20 ℃), nano alumina and ethanol are added, and the mixture is fully stirred and filtered to obtain the main agent of the high-resistance waterproof adhesive, and the main agent does not generate a gel phenomenon after being stored for 60 days at the temperature of 5-40 ℃, and has good storage stability. Adding formic acid and fully stirring before use to obtain the high-resistance water-resisting adhesive.

The BOPP film and the PE film are compounded by using the prepared high-resistance waterproof adhesive, and the process is as follows: on a dry compounding machine, a BOPP film with the thickness of 18 mu m is placed on a main unreeling machine, and a high-resistance water-proof adhesive is coated on the BOPP film, wherein the coating amount is 4 g per square meter. Drying after gluing, wherein the oven temperature of the compound machine is 70 ℃, 75 ℃ and 75 ℃ respectively. And placing a PE film with the thickness of 40 mu m on the auxiliary unwinding roll, and attaching the PE film and the BOPP film subjected to gluing and drying under the action of a composite hot roll to obtain a semi-finished film. The temperature of the composite hot roller is 60 ℃, and the machine speed is 80 meters per minute. And (3) placing the semi-finished film into a curing chamber with the temperature of 60 ℃, and curing for 24 hours to obtain the composite film.

The composite strength of the composite membrane is measured to be 1.8N, and the oxygen transmission capacity is measured to be 0.98cm³/m²·24h·1MPa。

Example 6

Polyvinyl alcohol-1799 and water were added to a heatable reaction vessel and heated to 85 ℃ with stirring to dissolve completely. Cooling to 30 ℃, adding polyamide epichlorohydrin resin, fully stirring and mixing, heating to 45 ℃, preserving heat and reacting for 10 hours, cooling to 28 ℃ at normal temperature, adding a rare earth stabilizer and a hydrocarbon surfactant, fully stirring, filtering to obtain the high-resistance water-resisting adhesive main agent, and storing the main agent at 5-40 ℃ for 60 days without generating a gel phenomenon, wherein the storage stability is good. Adding isocyanate and fully stirring before use to obtain the high-resistance waterproof adhesive.

The BOPP film and the PE film are compounded by using the prepared high-resistance waterproof adhesive, and the process is as follows: on a dry compounding machine, a BOPP film with the thickness of 20 mu m is placed on a main unreeling machine, and a high-resistance water-proof adhesive is coated on the BOPP film, wherein the coating amount is 8 g per square meter. Drying after gluing, wherein the oven temperature of the compound machine is 75 ℃, 75 ℃ and 75 ℃. And (3) placing a PE film with the thickness of 40 mu m in the auxiliary unwinding roll, and attaching the PE film and the BOPP film subjected to gluing and drying under the action of a composite hot roll to obtain a semi-finished film. The temperature of the composite hot roller is 60 ℃, and the machine speed is 100 meters per minute. And (3) putting the semi-finished film into a curing chamber with the temperature of 60 ℃ for curing for 48 hours.

The composite strength of the composite film was measured to be 3N, and the oxygen transmission was measured to be 1.1cm³/m²·24h·1MPa。

Example 7

Polyvinyl alcohol-1799 and water were added to a heatable reaction vessel and heated to 80 ℃ with stirring to dissolve completely, according to the following formulation. After the temperature is reduced to 20 ℃, adding polyurethane, fully stirring and mixing, heating to 20 ℃, preserving heat and reacting for 2 hours, then reducing to the normal temperature of 15 ℃, adding a rare earth stabilizer and a hydrocarbon surfactant (the proportion of the two is 1:0.5), fully stirring, and filtering to obtain the main agent of the high-resistance waterproof adhesive, wherein the main agent does not generate a gel phenomenon after being stored for 60 days at the temperature of 20 ℃, and has good storage stability. The oxazoline polymer is added before use and fully stirred to obtain the high-resistance waterproof adhesive.

The prepared high-resistance waterproof adhesive is coated on a PE film by a coating machine, the coating amount is 1 gram per square meter, and then drying is carried out, wherein the drying oven temperature of the coating machine is 60 ℃,65 ℃ and 70 ℃, and the machine speed is 90 meters per minute. And compounding the BOPA film and the PE film which is glued and dried on a solvent-free compound machine by using a solvent-free adhesive, and curing for 24 hours in a curing chamber at the temperature of 45 ℃ to obtain the composite film.

The composite strength of the composite film was measured to be 3N, and the oxygen transmission was measured to be 0.2cm³/m²·24h·1MPa。

Example 8

Polyvinyl alcohol-1799 and water were added to a heatable reaction vessel and heated to 80 ℃ with stirring to dissolve completely, according to the following formulation. After the temperature is reduced to 20 ℃, adding polyester resin, fully stirring and mixing, heating to 15 ℃, preserving heat and reacting for 4 hours, then reducing to the normal temperature of 15 ℃, adding a rare earth stabilizer and a hydrocarbon surfactant, fully stirring, filtering to obtain the main agent of the high-resistance waterproof adhesive, and the main agent does not generate a gel phenomenon after being stored for 60 days at the temperature of 15 ℃, and has good storage stability. Adding maleic anhydride before use, and fully stirring to obtain the high-resistance water-resisting adhesive.

The prepared high-resistance water-resisting adhesive is coated on a CPP film by a coating machine, the coating amount is 1 gram per square meter, and then drying is carried out, wherein the drying oven temperature of the coating machine is 60 ℃,65 ℃ and 70 ℃, and the machine speed is 90 meters per minute. And compounding the BOPA film and the CPP film subjected to gluing and drying by using a solvent polyurethane adhesive on a dry compounding machine, and curing for 24 hours in a curing chamber at the temperature of 45 ℃ to obtain the composite film.

The composite strength of the composite film was measured to be 3N, and the oxygen transmission was measured to be 0.2cm³/m²·24h·1MPa。

While specific embodiments of the invention have been described in detail, those skilled in the art will understand that: various modifications and changes in detail can be made in light of the overall teachings of the disclosure, and such changes are intended to be within the scope of the present invention. The full scope of the invention is given by the appended claims and any equivalents thereof.

Claims (34)

1. An aqueous adhesive comprising:

(1) 1% -30% of barrier resin;

(2) 0.1% -20% of a prepolymerization agent;

(3) 0.01-20% of crosslinking curing agent;

(4) 0% -5% of nano inorganic matter;

(5) 0% -2% of heat stabilizer and/or light stabilizer;

(6) 0% -10% of leveling tackifier;

(7) 0% -2% of a surfactant; and

(8) 11% -98.89% of water;

wherein each weight percent is based on the total weight of the aqueous adhesive;

the barrier resin is selected from: polyvinyl alcohol;

the prepolymerization agent is selected from: polyurethane, saturated polyester, polyester resin, and any combination thereof;

the crosslinking curing agent is selected from: aliphatic carboxylic acids and derivatives thereof, oxazoline polymers, isocyanates, and any combinations thereof;

the nano inorganic substance is selected from: nano silicon oxide, nano aluminum oxide, nano titanium oxide, nano zinc oxide, nano silver oxide, graphene, nano montmorillonite, nano talcum powder, nano calcium carbonate, nano clay and any combination thereof;

the heat and light stabilizers are independently selected from: inorganic lead salt and organic lead salt heat stabilizer, metal soap and metal salt stabilizer, organic tin stabilizer, organic antimony stabilizer, rare earth stabilizer, stearic acid, salicylate light stabilizer, benzoate light stabilizer, cyanoacrylate light stabilizer, benzophenone light stabilizer, hindered amine light stabilizer, zinc light shielding agent and any combination thereof;

the leveling tackifier is selected from: ethanol, methanol, isopropanol, butanol, glycol ethers, propylene glycol ethers, vinyl pyrrolidone, polyols, cellulose, chitosan, chitin, acrylamide, caprolactam, and any combination thereof;

the surfactant is selected from alkylphenol ethoxylates, dodecyl dimethyl ammonium oxide, fluorocarbon surfactants, hydrocarbon surfactants, alkylbenzene sulfonates, and any combination thereof.

2. The aqueous adhesive of claim 1 wherein the aliphatic carboxylic acid and derivatives thereof are selected from the group consisting of citric acid, acrylic acid, maleic acid, sorbic acid, itaconic acid, acetic anhydride and maleic anhydride.

3. The aqueous adhesive of claim 1, further comprising an antioxidant, a defoamer, or a colorant.

4. The aqueous adhesive of claim 1 comprising: 1 to 30 percent of barrier resin, 0.1 to 20 percent of pre-polymerization agent, 0.01 to 20 percent of crosslinking curing agent and 11 to 98.89 percent of water;

or comprises: 1 to 30 percent of barrier resin, 0.1 to 20 percent of pre-polymerization agent, 0.01 to 20 percent of crosslinking curing agent, 0 to 5 percent of nano inorganic matter, 0 to 10 percent of leveling tackifier and 11 to 98.89 percent of water;

or comprises: 1 to 30 percent of barrier resin, 0.1 to 20 percent of pre-polymerization agent, 0.01 to 20 percent of crosslinking curing agent, 0 to 2 percent of heat stabilizer and/or light stabilizer, 0 to 2 percent of surfactant and 11 to 98.89 percent of water.

5. The aqueous adhesive of any one of claims 1-4 having one or more of the following characteristics:

(1) the crosslinking curing agent is selected from: citric acid, oxazoline polymers, isocyanates, maleic anhydride, and any combination thereof;

(2) the nano inorganic matter is nano alumina;

(3) the heat stabilizer or light stabilizer is a rare earth stabilizer;

(4) the leveling tackifier is ethanol;

(5) the surfactant is a hydrocarbon surfactant.

6. A composite film comprising an adhesion barrier layer formed from the aqueous adhesive of any one of claims 1 to 5.

7. The composite film of claim 6 comprising, in order, a first substrate layer consisting essentially of a polymer or paper, the bonding barrier layer, and a second substrate layer consisting essentially of a polymer or paper.

8. The composite film of claim 7 wherein at least one of the first and second substrate layers consists essentially of a polymer.

9. The composite film of claim 7 wherein the polymer in the first substrate layer and the polymer in the second substrate layer are independently selected from the group consisting of polyethylene, polypropylene, polyamide, polyethylene terephthalate, and polystyrene.

10. The composite film of claim 6 wherein the bond barrier layer has a thickness of from 2 μm to 6 μm.

11. The composite film of claim 6 having a total thickness of from 30 μm to 150 μm.

12. The composite film of claim 6 having a composite strength of from 1.5N to 3N.

13. The composite membrane of claim 6 having an oxygen transmission of 0.2 to 0.5cm³/m²·24h·1MPa。

14. The composite film of claim 7 which is a packaging film, the first substrate layer being a protective layer and the second substrate layer being a sealant layer.

15. The composite film of claim 14 wherein the protective layer consists essentially of polyamide, polypropylene, or polyethylene terephthalate.

16. The composite film of claim 14 wherein the sealing layer consists essentially of polyethylene or polypropylene.

17. The composite film of claim 14 further comprising a print layer, an additional adhesive layer, or an additional barrier layer.

18. A method of making a composite membrane comprising the step of using the aqueous adhesive of any one of claims 1-5.

19. The method of claim 18, which is dry compounding.

20. The method of claim 18, comprising the steps of:

step 1: providing a first substrate, a second substrate and an aqueous adhesive;

step 2: coating a water-based adhesive on the surface of the first substrate;

and step 3: heating the coated first substrate;

and 4, step 4: under the conditions of heating and pressurizing, the second base material is attached to the first base material treated in the step 3 to obtain a semi-finished product;

and 5: and (4) curing the semi-finished product obtained in the step (4).

21. The method of claim 20, wherein the first substrate and the second substrate are each independently selected from the group consisting of polymeric films and papers.

22. The method of claim 20, wherein at least one of the first substrate and the second substrate is a polymer film.

23. The method of claim 21, wherein said polymeric film is selected from the group consisting of polyethylene film, polypropylene film, polyamide film, polyethylene terephthalate film, and polystyrene film.

24. The method of claim 20, wherein the first substrate is selected from the group consisting of: polyamide films, polypropylene films, polyethylene terephthalate films.

25. The method of claim 20, wherein the second substrate is selected from the group consisting of: polyethylene films, polypropylene films.

26. The method of claim 20, wherein the first substrate has a thickness of 10 μ ι η to 250 μ ι η.

27. The method of claim 20, wherein the second substrate has a thickness of 10 μ ι η to 250 μ ι η.

28. The method of claim 20, wherein the first substrate and the second substrate each have a surface tension coefficient of 38 dynes or greater.

29. The method of claim 20, wherein between step 3 and step 4 further comprising: and (3) coating the first substrate treated in the step 3 with an additional adhesive.

30. The method of claim 20, having one or more of the following features:

(1) in step 2, coating the water-based adhesive on the first substrate in an amount of 0.3-8 g per square meter;

(2) in step 3, the heating is carried out in three sections, the temperature is 60-75 ℃, 65-75 ℃ and 70-85 ℃ in sequence, or the heating is carried out in four sections, the temperature is 60-70 ℃, 70-75 ℃, 75-80 ℃ and 75-85 ℃ in sequence;

(3) the heating temperature in the step 4 is 50-65 ℃;

(4) in the step 5, the curing temperature is 40-80 ℃;

(5) in the step 5, the curing time is 12-72 hours.

31. A process for preparing the aqueous adhesive of any one of claims 1 to 5 comprising the steps of:

step 1: providing the barrier resin, a pre-polymerization agent, a crosslinking curing agent and water in proportion;

step 2: dissolving the barrier resin in water to obtain a semi-finished product;

and step 3: mixing the pre-polymerization agent and the semi-finished product, and optionally adding a nano inorganic substance, a heat stabilizer, a light stabilizer, a leveling tackifier, a surfactant or any combination thereof into the mixture of the pre-polymerization agent and the semi-finished product to obtain a water-based adhesive main agent;

and 4, step 4: and mixing the water-based adhesive main agent with a crosslinking curing agent to obtain the water-based adhesive.

32. Use of the aqueous adhesive according to any of claims 1 to 5 for the preparation of composite films.

33. Use of a composite film according to any of claims 6 to 17 for packaging an article.

34. A package comprising the composite film of any one of claims 6-17.