High-barrier paper with heat sealing performance and preparation method thereof

Abstract

The high-barrier paper with the heat sealing performance is characterized by comprising paper, an adhesive layer, an evaporation layer and a heat-sealable release layer which are sequentially arranged, the evaporation layer is a silicon oxide or aluminum oxide barrier layer evaporated on one side of the heat-sealable release layer, the evaporation layer is compounded on one side of the paper through the adhesive layer, and the heat-sealable release layer is arranged on the other side of the paper through the heat-sealable release layer. The heat-sealable release layer has heat sealability and peelability. The invention further provides a preparation method of the high-barrier paper with the heat sealing performance. The high-barrier paper with the heat-sealing property not only has high barrier property (water resistance and oxygen resistance), but also has a heat-sealing function, and also has recyclable environment-friendly performance (repulping and recycling). The high-barrier paper with the barrier layer and the heat sealing performance can be used for fresh-keeping packaging of food and medicines.

Description

Technical Field

[0001] The present invention relates to a composite packaging material, and particularly to a high-barrier paper having heat-sealing performance and a preparation method thereof. Background Art

[0002] Internationally, a coating material with an oxygen transmission rate less than 3.8 cm 3 / (m 2 ·24 h·0.1 MPa) is called a high-barrier material. High-barrier materials have the characteristics of blocking oxygen, water vapor, oil, and odor. It can effectively maintain the taste and smell of food in the package, prevent product deterioration, and extend the shelf life and quality guarantee period of the commodity. In the global packaging industry, especially in food and pharmaceutical packaging, more and more manufacturers begin to use packaging materials with high-barrier performance. Traditional high-barrier materials are mainly plastic packaging materials. With the improvement of global environmental protection and resource conservation awareness, recyclable paper high-barrier packaging materials have received increasing attention.

[0003] In order to obtain a paper packaging material with high oxygen and water vapor barrier properties, the traditional method is to evaporate a layer of high-barrier silicon oxide or aluminum oxide on a plastic film and then compound it with paper to obtain a paper-plastic composite high-barrier packaging material. However, the barrier paper-plastic products manufactured by this method are non-recyclable and non-degradable, which is not conducive to environmental protection and resource conservation. Some also use paper and aluminum foil composites to meet the requirements of high-barrier packaging materials through the high-barrier properties of aluminum foil. However, this packaging material will waste a large amount of aluminum foil and is also not conducive to resource conservation. There is also a method of coating a layer of polyvinylidene chloride (PVDC) coating with high-barrier function on paper products, which can play a good role in blocking oxygen and water vapor. However, the barrier paper manufactured by this method contains a polyvinylidene chloride (PVDC) coating, and polyvinylidene chloride and its decomposition products have relatively high toxicity, and the safety and hygiene performance is poor, so it is not suitable for packaging materials such as food and medicine. Some people also use PVA with high-barrier function as a barrier coating. However, PVA belongs to a highly hydrophilic polymer, which not only has no water blocking effect but is very easy to absorb moisture in the air, resulting in the complete disappearance of oxygen barrier performance. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a high-barrier paper having heat-sealing performance and a preparation method thereof. This high-barrier paper having heat-sealing performance not only has high barrier properties (water and oxygen barrier), but also has heat-sealing performance and recyclable environmental protection performance. The technical solution adopted is as follows: A high-barrier paper with heat-sealing performance, characterized in that it comprises a paper, an adhesive layer, a vapor deposition layer and a heat-sealable release layer arranged in sequence. The vapor deposition layer is a silicon oxide or aluminum oxide barrier layer vapor-deposited on one side of the heat-sealable release layer. The vapor deposition layer is compounded on one side of the paper through the adhesive layer. The heat-sealable release layer has heat-sealing performance and easy peelability.

[0005] In the above-mentioned high-barrier paper, the heat-sealable release layer has heat-sealing performance and easy peelability. When used as a packaging material, it can be used as a heat-sealing layer. For example, when making a paper packaging bag with the above-mentioned high-barrier paper, the heat-sealable release layers of the papers on both sides at the bag mouth are both in the innermost layer. By applying pressure and heat, the heat-sealable release layers of the papers on both sides can be heat-sealed together to achieve sealing.

[0006] In a preferred embodiment, a graphic printing layer is provided on the other side of the above-mentioned paper. According to needs, the required patterns and texts can be printed on the other side of the paper.

[0007] The present invention also provides a preparation method of the above-mentioned high-barrier paper with heat-sealing performance, characterized by comprising the following steps: (1) Making a heat-sealable release film Taking an untreated corona PET film as a carrier layer, applying a polyurethane coating on the carrier layer with a polyurethane coating material. After the polyurethane coating is cured, a heat-sealable release layer with heat-sealing performance and capable of peeling from the carrier layer is formed; (2) Making a vapor deposition layer Vacuum vapor-depositing a layer of aluminum oxide or silicon oxide on the heat-sealable release layer to form a vapor deposition layer, that is, an aluminum oxide or silicon oxide barrier layer, to obtain a composite layer material; (3) Making a high-barrier paper Coating an adhesive layer on one side of the paper, and then compounding the composite layer material obtained in step (2) with the paper. The vapor deposition layer in the composite layer material is adhered to one side of the paper through the adhesive layer; then the carrier layer is peeled off (that is, the carrier layer is separated from the heat-sealable release layer) to obtain the required high-barrier paper with heat-sealing performance.

[0008] Preferably, in step (1), the coating amount of the polyurethane coating is 3 - 8 g / m 2 .

[0009] In step (1), after coating the polyurethane coating, a covering film is compounded on the polyurethane coating to form a composite film and wound up. Then, the composite film roll is placed in an environment with a humidity less than 40% and a temperature of 30 - 50 °C for curing for 24 - 72 hours (preferably 48 hours); after curing, the covering film is peeled off and recycled (the recycled covering film can be reused), that is, a heat-sealable release layer is formed on the carrier layer. The covering film uses an untreated corona OPP film.

[0010] Preferably, in step (1), a solventless laminator is used during the coating and laminating processes, and the coating and laminating speeds are 100 - 400 m / min.

[0011] Preferably, each operation in step (1) above is carried out in an environment with an air humidity of less than 40%.

[0012] Preferably, in step (2), the thickness of the evaporation coating layer is 5 - 50 nm. Vacuum evaporation coating with silicon oxide is preferably used.

[0013] Preferably, in step (3), after the composite layer material is laminated with the paper and wound up, it is cured for 24 - 72 hours (preferably 48 hours) in an environment with a humidity of 60 - 80% and a temperature of 30 - 50 °C, and then the carrier layer is peeled off after curing.

[0014] Preferably, in step (3), a solventless laminator is used during the coating and laminating processes, and the coating and laminating speeds are 100 - 400 m / min.

[0015] Preferably, in step (3), the coating amount of the adhesive layer is 2 - 8 g / m 2 。

[0016] In the preferred solution, the polyurethane coating used in step (1) above includes component A and component B; Component A is made from raw materials with the following weight ratios: isophorone diisocyanate 10 - 20%, hexamethylene diisocyanate 20 - 50%, 1,4 - cyclohexane diisocyanate 0 - 50%, cyclohexane dimethylene diisocyanate 0 - 40%, norbornane diisocyanate 0 - 30%; Component B is made from raw materials with the following weight ratios: dimer acid polyester diol 30 - 60%, polyetheramine 15 - 30%, polyaspartate 15 - 30%, dihydroxy polydimethylsiloxane 1 - 5%, silane coupling agent 1 - 5%; The ratio of component A and component B is determined according to an R value of 1.02 - 1.10, where the R value is the molar ratio of the total isocyanate group (-NCO) to the total hydroxyl group (-OH) of component A and component B.

[0017] More preferably, component A is made from raw materials with the following weight ratios: isophorone diisocyanate 10 - 20%, hexamethylene diisocyanate 20 - 50%, 1,4 - cyclohexane diisocyanate 0.2 - 20%, cyclohexane dimethylene diisocyanate 0.2 - 20%, norbornane diisocyanate 0.2 - 20%.

[0018] More preferably, the molecular weight of the above - mentioned dimer acid polyester diol is 2000 - 2500, and the hydroxyl value is 35 - 45. In a specific solution, the above - mentioned dimer acid polyester diol is a dimer acid polyester diol polymerized from oleic acid and 1,6 - hexanediol (such as Boyuan BY3026).

[0019] More preferably, the molecular weight of the above polyetheramine is 400 - 1000. In a specific embodiment, the molecular weight of the above polyetheramine is 400 (such as Huntsman T - 403).

[0020] More preferably, the molecular weight of the above polyaspartic acid ester is 400 - 600 (such as Feiyang New Materials F520).

[0021] More preferably, the molecular weight of the above dihydroxypolydimethylsiloxane is 500 - 2000. In a specific embodiment, the molecular weight of the above dihydroxypolydimethylsiloxane is about 1000 (such as SiHai's 209 hydroxy silicone oil).

[0022] The above silane coupling agent can be silane coupling agent KH - 560 or silane coupling agent KH - 792.

[0023] In a more preferred embodiment, the preparation method of the above polyurethane coating comprises the following steps: (1a) Prepare Component A (1a - 1) Weigh the following raw materials: isophorone diisocyanate 10 - 20%, hexamethylene diisocyanate 20 - 50%, 1,4 - cyclohexane diisocyanate 0 - 50%, cyclohexane dimethylene diisocyanate 0 - 40%, norbornane diisocyanate 0 - 30%; (1a - 2) Mix the isophorone diisocyanate, hexamethylene diisocyanate, 1,4 - cyclohexane diisocyanate, cyclohexane dimethylene diisocyanate and norbornane diisocyanate prepared in step (1a - 1) evenly to obtain Component A for standby; (2a) Prepare Component B (2a - 1) Weigh the following raw materials: dimer acid polyester diol 30 - 60%, polyetheramine 15 - 30%, polyaspartic acid ester 15 - 30%, dihydroxypolydimethylsiloxane 1 - 5%, silane coupling agent 1 - 5%; (2a - 2) Mix the dimer acid polyester diol, polyetheramine, polyaspartic acid ester, dihydroxypolydimethylsiloxane and silane coupling agent prepared in step (2a - 1) evenly to obtain Component B for standby; (3a) Prepare the polyurethane coating Determine the ratio of Component A and Component B according to an R value of 1.02 - 1.10, and take Component A and Component B to mix evenly to obtain the required polyurethane coating.

[0024] More preferably, in step (3a), when applying, the A component and the B component are preheated to 40-60 °C (preferably 45 °C) respectively. Through precise metering (that is, determining the ratio of the A component and the B component according to an R value of 1.02-1.10, metering the A component and the B component and feeding them into a pipeline mixer), they are added to the glue tank of the solventless laminator by the pipeline mixer for the solventless laminator to perform coating.

[0025] The polyurethane coating used in the above step (1) is a two-component solventless polyurethane. After curing, the coating has high density and hardness, has a certain barrier property, and plays a certain barrier role against water vapor, oil and oxygen; and after curing, the coating has thermoplasticity and good heat-sealing performance (it can be heat-sealed at 130 °C). At the same time, the coating has good peelability for transfer. After the coating is matured, it is easy to peel off from the covering film (such as a non-corona-treated OPP film) first, and then after vacuum aluminizing or siliconizing, it can also peel off from the carrier layer (such as a non-corona-treated PET film), transferring the heat-sealable release layer to the paper. However, the coating formed by the existing ordinary polyurethane coating on the PET film does not have peelability.

[0026] The above A component is isocyanate, which is a reactive hard segment component of the heat-sealable release layer. When used in combination, it can not only improve the barrier property and peelability of the release layer, but also keep the coating having a certain flexibility. The functions of its various components are as follows: isophorone diisocyanate endows the coating with properties such as strength, temperature resistance, and wear resistance, and at the same time can improve flexibility, film-forming performance, and is beneficial to reducing the heat-sealing temperature; hexamethylene diisocyanate (HDI) has good crystallization performance, can reduce the heat-sealing temperature, and can improve the barrier property after curing; 1,4-cyclohexane diisocyanate (CHDI) is a reactive hard segment component of the heat-sealable release layer, has a compact and more symmetrical molecular structure, enables the cured heat-sealable release layer to form a more precise hard segment, improves the barrier property, solvent resistance, and water resistance, and has a high softening temperature and a low glass transition temperature; norbornane diisocyanate (NBDI) enables the heat-sealable release layer to have high thermal stability, hardness, and heat resistance after curing, and improves the peelability.

[0027] The above B component is a polymer polyol with hydroxyl or amino groups, which is a soft segment component of the heat-sealable release layer. After curing with the A component, the heat-sealable release layer can have good peelability, heat-sealability and a certain barrier property, and also improve the adhesion of vapor-deposited silicon oxide. The functions of its various components are: dimer acid polyester diol endows the heat-sealable release layer with flexibility and water resistance; polyaspartate can improve the peelability, hardness, barrier property and curing speed of the heat-sealable release layer; dihydroxy polydimethylsiloxane can reduce the surface friction coefficient of the heat-sealable release layer, improve the flatness, reduce the static electricity generated during film peeling, and at the same time improve the adhesion between the heat-sealable release layer and the vapor-deposited layer.

[0028] In a preferred embodiment, the adhesive used in the above step (3) is a solvent-free moisture-curing transfer adhesive, which is made from raw materials in the following weight ratios: 30-65% of dimer acid polyester diol, 5-20% of pentaerythritol polyoxypropylene tetraol, 5-25% of neopentyl glycol poly(ethylene terephthalate) diol, 10-30% of diphenylmethane diisocyanate, and 0.2-1% of bis(morpholinyl)diethyl ether.

[0029] More preferably, the molecular weight of the above dimer acid polyester diol is 2000-2500 and the hydroxyl value is 35-45. In a specific embodiment, the above dimer acid polyester diol is a dimer acid polyester diol polymerized from oleic acid and 1,6-hexanediol (for example, Boyuan BY3026).

[0030] More preferably, the molecular weight of the above pentaerythritol polyoxypropylene tetraol is 500-1000 (for example, Yinuowei 380).

[0031] More preferably, the molecular weight of the above neopentyl glycol poly(ethylene terephthalate) diol is 500-2000. In a specific embodiment, the molecular weight of the above neopentyl glycol poly(ethylene terephthalate) diol is 2000 (for example, Huiyuan Technology P320).

[0032] In a more preferred embodiment, the preparation method of the above solvent-free moisture-curing transfer adhesive successively includes the following steps: (1b) Weigh the following raw materials by weight: 30-65% of dimer acid polyester diol, 5-20% of pentaerythritol polyoxypropylene tetraol, 5-25% of neopentyl glycol poly(ethylene terephthalate) diol, 10-30% of diphenylmethane diisocyanate, and 0.2-1% of bis(morpholinyl)diethyl ether; (2b) Add the dimer acid polyester diol, pentaerythritol polyoxypropylene tetraol, and neopentyl glycol poly(ethylene terephthalate) diol prepared in step (1b) into a reaction kettle, then heat the materials in the reaction kettle to 105-120 °C, and pump water for 1-2 hours under a vacuum of -(6-10)×10 -4 MPa; (3b) Cool the materials in the reaction kettle to below 50 °C, add diphenylmethane diisocyanate, and then react at 75-85 °C for 2-4 hours (preferably react at 80 °C for 3 hours); (4b) Cool the materials in the reaction kettle to 40-60 °C (preferably 50 °C), then add bis(morpholinyl)diethyl ether and stir evenly to obtain a solvent-free moisture-curing transfer adhesive, which is sealed for later use.

[0033] When the above solvent-free moisture-curing transfer adhesive is used, it is heated to 80-90 °C.

[0034] The functions of the components in the above solvent-free moisture-curing transfer adhesive are as follows: The isocyanate serves as the hard segment part of the solvent-free moisture-curing transfer adhesive, endowing the adhesive layer with properties such as strength, heat resistance, and abrasion resistance. Diphenylmethane diisocyanate (MDI) is used as the isocyanate, which can increase the reaction rate of polyurethane and ensure a relatively fast curing rate after the solvent-free moisture-curing transfer adhesive is compounded. The dimer acid polyester diol serves as the soft segment part of the solvent-free moisture-curing transfer adhesive, endowing the adhesive layer with properties such as flexibility, elasticity, and water resistance. Pentaerythritol polyoxypropylene tetrol (pentaerythritol polyoxypropylene tetrol is a pentaerythritol polyether polymerized from pentaerythritol and propylene oxide, also known as pentaerythritol polypropylene oxide ether tetrol) is the crosslinked soft segment part of the solvent-free moisture-curing transfer adhesive, increasing the soft segment content and crosslinking points, raising the glass transition temperature of the solvent-free moisture-curing transfer adhesive, and improving the barrier property of the adhesive layer after curing. Neopentyl glycol poly(ethylene terephthalate) diol (a polyester diol polymerized from terephthalic acid and neopentyl glycol) is the soft segment component of the solvent-free moisture-curing transfer adhesive, which can rapidly increase the low-temperature viscosity of the solvent-free moisture-curing transfer adhesive during application, rapidly increase the viscosity of the coated adhesive layer, reduce the penetration of the solvent-free moisture-curing transfer adhesive into the paper, resulting in incomplete transfer or insufficient fastness, and reduce the coating amount and improve the barrier property. Bis(morpholinyl)diethyl ether (DMDEE) is a moisture-curing selective catalyst, which can increase the reaction rate between the adhesive layer and water vapor, reduce the curing time, and improve the production efficiency.

[0035] Compared with traditional high-barrier papers, the high-barrier paper with heat-sealing performance of the present invention not only has high barrier properties (water barrier and oxygen barrier), but also has a heat-sealing function and an environmentally friendly property of being recyclable (re-pulpable and recyclable).

[0036] In addition, the product has good environmental protection and safety and hygiene properties during manufacturing. In particular, when the polyurethane coating used in step (1) is a two-component solvent-free polyurethane and the adhesive used in step (3) is a solvent-free moisture-curing transfer adhesive, there is no VOC emission during the manufacturing process, no toxic substances are contained or released, and energy is saved (using a solvent-free system and not requiring heating or radiation energy during the curing process).

[0037] The high-barrier paper with a barrier layer and heat-sealing performance of the present invention can be used for the fresh-keeping packaging of foods and drugs. Detailed implementation manners

[0038] Example 1. In this example, the preparation method of the polyurethane coating (used to form a heat-sealable release layer) used in step (1) includes the following steps: (1a) Prepare component A (1a-1)Equipped with the following raw materials by weight: isophorone diisocyanate 100 g (accounting for 10%), hexamethylene diisocyanate 500 g (accounting for 50%), 1,4-cyclohexane diisocyanate 20 g (2%), cyclohexane dimethylene diisocyanate 350 g (accounting for 35%), norbornane diisocyanate 30 g (accounting for 3%); (1a-2)Mix the isophorone diisocyanate, hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, cyclohexane dimethylene diisocyanate and norbornane diisocyanate equipped in step (1a-1) evenly to obtain component A for standby; (2a)Prepare component B (2a-1)Equipped with the following raw materials by weight: dimer acid polyester diol 480 g (accounting for 48%), polyetheramine 190 g (accounting for 19%), polyaspartate 240 g (24%), dihydroxy polydimethylsiloxane 50 g (accounting for 5%), silane coupling agent 40 g (accounting for 4%); The above dimer acid polyester diol is a dimer acid polyester diol polymerized from oleic acid and 1,6-hexanediol (such as Baiyuan BY3026, with a molecular weight of 2500 and a hydroxyl value of 39.4); the polyetheramine has a molecular weight of 400 (such as Huntsman T-403); the polyaspartate has a molecular weight of 590 (such as Feiyang New Materials F520); the dihydroxy polydimethylsiloxane has a molecular weight of about 1000 (such as SiHai's 209 hydroxyl silicone oil); the silane coupling agent uses silane coupling agent KH-560; (2a-2)Mix the dimer acid polyester diol, polyetheramine, polyaspartate, dihydroxy polydimethylsiloxane and silane coupling agent equipped in step (2a-1) evenly to obtain component B for standby; (3a)Prepare polyurethane coating Determine the ratio of component A and component B according to an R value of 1.077 (the mass ratio of component A and component B is A:B = 1:3.5), take component A and component B and mix them evenly to obtain the required polyurethane coating.

[0039] In the above step (3a), during application, preheat component A and component B to 45°C respectively, through precise measurement (that is, determine the ratio of component A and component B according to an R value of 1.077, measure component A and component B and feed them into a pipeline mixer), and use the pipeline mixer to add them into the glue tank of a solventless laminator for the solventless laminator to perform coating.

[0040] In this embodiment, the preparation method of the solventless moisture-curing transfer adhesive (used for coating an adhesive layer on one side of paper) used in step (3) successively includes the following steps: (1b) The following raw materials are prepared by weight: 400 g (40%) of dimer acid polyester diol, 190 g (19%) of pentaerythritol polyoxypropylene tetraol, 155 g (15.5%) of polyneopentyl terephthalate diol, 250 g (25%) of diphenylmethane diisocyanate, and 5 g (0.5%) of bismorpholinyl diethyl ether; The dimer acid polyester diol is a dimer acid polyester diol polymerized from oleic acid and 1,6-hexanediol (e.g., BY3026 from Baiyuan, molecular weight 2500, hydroxyl value 39.4); the molecular weight of pentaerythritol polyoxypropylene tetraol is 856 (e.g., INOV 380); the molecular weight of polyneopentyl terephthalate diol is 2000 (e.g., P320 from Huiyuan Technology); (2b) Add the dimer acid polyester diol, pentaerythritol polyoxypropylene tetraol and poly(neopentyl terephthalate) diol prepared in step (1b) into a reaction kettle, and then heat the materials in the reaction kettle to 110° C. and place under vacuum at -8×10 -4 MPa for 1.5 hours; (3b) The contents in the reactor were cooled to 45°C, diphenylmethane diisocyanate was added, and then reacted at 80°C for 3 hours; (4b) The material in the reaction kettle is cooled to 50° C., and then bismorpholinyl diethyl ether is added and stirred evenly to obtain a solvent-free moisture-curing transfer adhesive, which is then sealed for later use.

[0041] In this embodiment, the method for preparing high barrier paper with heat sealing performance comprises the following steps: (1) Making heat-sealable release film The PET film without corona discharge is used as the carrier layer, and the polyurethane coating is applied on the carrier layer with polyurethane coating (the coating amount of the polyurethane coating is 4g / m 2 ); After the polyurethane coating is applied, a covering film is laminated on the polyurethane coating (the covering film is an OPP film without corona treatment) to form a composite film and roll it up, and then the composite film roll is placed in an environment with a humidity of less than 40% and a temperature of 40°C for aging for 48 hours; after aging, the covering film is peeled off and recovered (the recovered covering film can be reused), that is, a heat-sealable release layer with heat-sealability and capable of being peeled off from the carrier layer is formed on the carrier layer; In step (1), a solvent-free laminating machine is used in the coating and laminating process, and the coating and laminating speed is 200 m / min; the glue tank and transfer roller of the solvent-free laminating machine are preheated to 45° C. The operations of step (1) are performed in an environment where the air humidity is less than 40%; (2) Making the Evaporation Layer Vacuum deposit a layer of aluminum oxide on the heat-sealable release layer to form a vapor-deposited layer (the thickness of the vapor-deposited layer is 40 nm), that is, an aluminum oxide barrier layer, to obtain a composite layer material; (3)Manufacture high-barrier paper Coat an adhesive layer on one side of the paper (the adhesive uses the above solvent-free moisture-curing transfer adhesive, and the solvent-free moisture-curing transfer adhesive is heated to 90 °C during use; the coating amount of the adhesive layer is 5 g / m 2 ), and then laminate the composite layer material obtained in step (2) with the paper. The vapor-deposited layer in the composite layer material is bonded to one side of the paper through the adhesive layer; then peel off the carrier layer (that is, the carrier layer is separated from the heat-sealable release layer) to obtain the required high-barrier paper with heat-sealing properties.

[0042] In step (3), after the composite layer material and the paper are laminated, they are wound up, and then cured for 48 hours in an environment with a humidity of 70% and a temperature of 45 °C, and the carrier layer is peeled off after curing.

[0043] In step (3), a solvent-free laminator is used during the coating and lamination process, and the coating and lamination speed is 150 m / min. The glue tank and transfer roller of the solvent-free laminator are preheated to 90 °C.

[0044] The obtained high-barrier paper with heat-sealing properties includes a paper, an adhesive layer, a vapor-deposited layer, and a heat-sealable release layer arranged in sequence. The vapor-deposited layer is an aluminum oxide barrier layer vapor-deposited on one side of the heat-sealable release layer. The vapor-deposited layer is laminated on one side of the paper through the adhesive layer, and the heat-sealable release layer has heat-sealing properties and easy peelability.

[0045] Example 2. In this example, the preparation method of the polyurethane coating (used to form the heat-sealable release layer) used in step (1) includes the following steps: (1a)Prepare component A (1a-1)By weight, prepare the following raw materials: 150 g of isophorone diisocyanate (accounting for 15%), 400 g of hexamethylene diisocyanate (accounting for 40%), 400 g of 1,4-cyclohexane diisocyanate (accounting for 40%), 20 g of cyclohexane dimethylene diisocyanate (accounting for 2%), and 30 g of norbornane diisocyanate (accounting for 3%); (1a-2)Mix the isophorone diisocyanate, hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, cyclohexane dimethylene diisocyanate, and norbornane diisocyanate prepared in step (1a-1) evenly to obtain component A and set it aside; (2a)Prepare component B (2a-1) It is equipped with the following raw materials by weight: 590 g of dimer acid polyester diol (accounting for 59%), 200 g of polyetheramine (accounting for 20%), 160 g of polyaspartate (accounting for 16%), 30 g of dihydroxy polydimethylsiloxane (accounting for 3%), and 20 g of silane coupling agent (accounting for 2%); The above-mentioned dimer acid polyester diol is a dimer acid polyester diol polymerized from oleic acid and 1,6-hexanediol (such as Boyuan BY3026, with a molecular weight of 2500 and a hydroxyl value of 39.4); the polyetheramine has a molecular weight of 400 (such as Huntsman T-403); the polyaspartate has a molecular weight of 590 (such as Feiyang New Materials F520); the dihydroxy polydimethylsiloxane has a molecular weight of about 1000 (such as SiHai's 209 hydroxyl silicone oil); the silane coupling agent is silane coupling agent KH-560; (2a-2) Mix the dimer acid polyester diol, polyetheramine, polyaspartate, dihydroxy polydimethylsiloxane, and silane coupling agent prepared in step (2a-1) evenly to obtain Component B for standby; (3a) Prepare polyurethane coating Determine the ratio of Component A and Component B according to an R value of 1.064 (the mass ratio of Component A and Component B is A:B = 1:3.9). Take Component A and Component B and mix them evenly to obtain the required polyurethane coating.

[0046] In the above step (3a), when applying, preheat Component A and Component B to 45°C respectively. Through precise measurement (that is, determine the ratio of Component A and Component B according to an R value of 1.064, measure Component A and Component B and feed them into a pipeline mixer), use the pipeline mixer to add them into the glue tank of a solventless laminator for the solventless laminator to perform coating.

[0047] In this embodiment, the preparation method of the solventless moisture-curing transfer adhesive (used for coating an adhesive layer on one side of paper) used in step (3) successively includes the following steps: (1b) It is equipped with the following raw materials by weight: 520 g of dimer acid polyester diol (accounting for 52%), 92 g of pentaerythritol polyoxypropylene tetrol (accounting for 9.2%), 200 g of neopentyl glycol polyterephthalate diol (accounting for 20%), 180 g of diphenylmethane diisocyanate (accounting for 18%), and 8 g of bis(morpholinyl)diethyl ether (accounting for 0.8%); The above-mentioned dimer acid polyester diol is a dimer acid polyester diol polymerized from oleic acid and 1,6-hexanediol (such as Boyuan BY3026, with a molecular weight of 2500 and a hydroxyl value of 39.4); the pentaerythritol polyoxypropylene tetrol has a molecular weight of 856 (such as Yinuowei 380); the neopentyl glycol polyterephthalate diol has a molecular weight of 2000 (such as Huiyuan Technology P320); (2b) Add the dimer acid polyester diol, pentaerythritol polyoxypropylene tetrol, and neopentyl glycol terephthalate diol equipped in step (1b) into the reaction kettle, then heat the materials in the reaction kettle to 115 °C, and pump water for 2 hours under a vacuum of -6×10 -4 MPa; (3b) Cool the materials in the reaction kettle to 50 °C, add diphenylmethane diisocyanate, and then react at 80 °C for 3 hours; (4b) Cool the materials in the reaction kettle to 50 °C, then add bis(morpholinyl)diethyl ether and stir evenly to obtain a solvent-free moisture-curing transfer adhesive, which is sealed for later use.

[0048] In this embodiment, the preparation method of the high-barrier paper with heat-sealing performance includes the following steps: (1) Prepare a heat-sealable release film Use an uncorona-treated PET film as the carrier layer, and coat a polyurethane coating on the carrier layer with a polyurethane coating (the coating amount of the polyurethane coating is 5 g / m 2 ); after coating the polyurethane coating, laminate a cover film (the cover film uses an uncorona-treated OPP film) on the polyurethane coating to form a composite film and wind it up. Then, place the composite film roll in an environment with a humidity of less than 40% and a temperature of 35 °C for 72 hours of curing; after curing, peel off and recycle the cover film (the recycled cover film can be reused), that is, a heat-sealable release layer with heat-sealing performance and capable of being peeled off from the carrier layer is formed on the carrier layer; In step (1), a solvent-free laminator is used during the coating and lamination processes, and the coating and lamination speed is 400 m / min; the glue tank and transfer roller of the solvent-free laminator are preheated to 45 °C; Each operation in step (1) is carried out in an environment with an air humidity of less than 40%; (2) Prepare an evaporation coating layer Vacuum-evaporate a layer of silicon oxide on the heat-sealable release layer to form an evaporation coating layer (the thickness of the evaporation coating layer is 10 nm), that is, a silicon oxide barrier layer, to obtain a composite layer material; (3) Prepare the high-barrier paper Coat an adhesive layer on one side of the paper (the adhesive uses the above-mentioned solvent-free moisture-curing transfer adhesive, and the solvent-free moisture-curing transfer adhesive is heated to 85 °C during use; the coating amount of the adhesive layer is 4 g / m 2 ), then laminate the composite layer material obtained in step (2) with the paper, and the evaporation coating layer in the composite layer material is adhered to one side of the paper through the adhesive layer; then peel off the carrier layer (that is, the carrier layer is separated from the heat-sealable release layer) to obtain the required high-barrier paper with heat-sealing performance.

[0049] In step (3), the composite layer material is rolled up after being composited with the paper, and then aged for 48 hours in an environment of 70% humidity and 40° C., and the supporting layer is peeled off after the ageing.

[0050] In step (3), a solvent-free laminating machine is used in the coating and laminating process, and the coating and laminating speed is 150 m / min. The glue tank and transfer roller of the solvent-free laminating machine are preheated to 85°C.

[0051] The obtained high-barrier paper with heat-sealing properties includes paper, an adhesive layer, a vapor-deposited layer and a heat-sealable release layer arranged in sequence, the vapor-deposited layer is a silicon oxide barrier layer vapor-deposited on one side of the heat-sealable release layer, the vapor-deposited layer is compounded on one side of the paper through the adhesive layer, and the heat-sealable release layer has heat-sealing properties and is easy to peel off.

[0052] Embodiment 3: In this embodiment, the preparation method of the polyurethane coating (for forming a heat-sealable release layer) used in step (1) comprises the following steps: (1a) Preparation of component A (1a-1) The following raw materials are prepared by weight: 200 g of isophorone diisocyanate (accounting for 20%), 250 g of hexamethylene diisocyanate (accounting for 25%), 250 g of 1,4-cyclohexane diisocyanate (accounting for 25%), 20 g of cyclohexane dimethylene diisocyanate (accounting for 2%), and 280 g of norbornane diisocyanate (accounting for 28%); (1a-2) mixing the isophorone diisocyanate, hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, cyclohexane dimethylene diisocyanate and norbornane diisocyanate prepared in step (1a-1) to obtain component A for standby use; (2a) Preparation of component B (2a-1) The following raw materials are prepared by weight: 380 g (38%) of dimer acid polyester diol, 300 g (30%) of polyether amine, 260 g (26%) of polyaspartic acid ester, 20 g (2%) of dihydroxy polydimethylsiloxane, and 40 g (4%) of silane coupling agent; The dimer acid polyester diol is a dimer acid polyester diol polymerized from oleic acid and 1,6-hexanediol (e.g., Baiyuan BY3026, molecular weight 2500, hydroxyl value 39.4); the molecular weight of the polyetheramine is 400 (e.g., Huntsman T-403); the molecular weight of the polyaspartic acid ester is 590 (e.g., Feiyang New Materials F520); the molecular weight of the dihydroxy polydimethylsiloxane is about 1000 (e.g., Sihai's 209 hydroxy silicone oil); the silane coupling agent is silane coupling agent KH-560; (2a-2) uniformly mixing the dimer acid polyester diol, polyetheramine, polyaspartic acid ester, dihydroxy polydimethylsiloxane and silane coupling agent prepared in step (2a-1) to obtain component B for standby use; (3a) Prepare polyurethane coating Determine the ratio of Component A and Component B according to an R value of 1.047 (the mass ratio of Component A and Component B is A:B = 1:2.9). Take Component A and Component B and mix them evenly to obtain the required polyurethane coating.

[0053] In the above step (3a), when applying, preheat Component A and Component B to 45 °C respectively. Through precise metering (that is, determine the ratio of Component A and Component B according to an R value of 1.047, meter Component A and Component B and feed them into a pipeline mixer), use the pipeline mixer to add them to the glue tank of a solventless laminator for the solventless laminator to perform coating.

[0054] In this embodiment, the preparation method of the solventless moisture-curing transfer adhesive (used for coating an adhesive layer on one side of paper) used in step (3) successively includes the following steps: (1b) Prepare the following raw materials by weight: 570 g of dimer acid polyester diol (accounting for 57%), 126 g of pentaerythritol polyoxypropylene tetrol (accounting for 12.6%), 100 g of neopentyl glycol terephthalate diol (accounting for 10%), 200 g of diphenylmethane diisocyanate (accounting for 20%), 4 g of bis(morpholinyl)diethyl ether (accounting for 0.4%); The above dimer acid polyester diol is a dimer acid polyester diol polymerized from oleic acid and 1,6-hexanediol (such as Boyuan BY3026, with a molecular weight of 2500 and a hydroxyl value of 39.4); the molecular weight of pentaerythritol polyoxypropylene tetrol is 856 (such as Yinuowei 380); the molecular weight of neopentyl glycol terephthalate diol is 2000 (such as Huiyuan Technology P320); (2b) Add the dimer acid polyester diol, pentaerythritol polyoxypropylene tetrol, and neopentyl glycol terephthalate diol prepared in step (1b) into a reaction kettle, then heat the materials in the reaction kettle to 120 °C, and pump water for 1.5 hours under a vacuum of -9×10 -4 MPa; (3b) Cool the materials in the reaction kettle to 48 °C, add diphenylmethane diisocyanate, and then react at 85 °C for 2.5 hours; (4b) Cool the materials in the reaction kettle to 48 °C, then add bis(morpholinyl)diethyl ether and stir evenly to obtain a solventless moisture-curing transfer adhesive, and seal it for standby.

[0055] In this embodiment, the preparation method of the high-barrier paper with heat-sealing performance includes the following steps: (1) Make a heat-sealable release film Use an untreated PET film as the carrier layer, and coat a polyurethane coating on the carrier layer with a polyurethane coating (the coating amount of the polyurethane coating is 6 g / m2 ); after applying the polyurethane coating, a covering film (the covering film uses a non-corona-treated OPP film) is laminated on the polyurethane coating to form a composite film and then wound up. Then, the composite film roll is cured in an environment with a humidity less than 40% and a temperature of 50 °C for 48 hours; after curing, the covering film is peeled off and recycled (the recycled covering film can be reused), that is, a heat-sealable release layer with heat-sealing performance and capable of being peeled off from the carrier layer is formed on the carrier layer; In step (1), a solventless laminator is used in the coating and lamination processes, and the coating and lamination speeds are 200 m / min; the glue tank and transfer roller of the solventless laminator are preheated to 45 °C; Each operation in step (1) is carried out in an environment with an air humidity less than 40%; (2) Produce the vapor deposition layer A layer of silicon oxide is vacuum-deposited on the heat-sealable release layer to form a vapor deposition layer (the thickness of the vapor deposition layer is 8 nm), that is, a silicon oxide barrier layer, to obtain a composite layer material; (3) Produce the high-barrier paper An adhesive layer is applied on one side of the paper (the adhesive uses the above-mentioned solventless moisture-curing transfer adhesive, and the solventless moisture-curing transfer adhesive is heated to 85 °C when in use; the coating amount of the adhesive layer is 3 g / m 2 ), and then the composite layer material obtained in step (2) is laminated with the paper, and the vapor deposition layer in the composite layer material is adhered to one side of the paper through the adhesive layer; then the carrier layer is peeled off (that is, the carrier layer is separated from the heat-sealable release layer) to obtain the required high-barrier paper with heat-sealing performance.

[0056] In step (3), after the composite layer material and the paper are laminated, they are wound up, and then cured in an environment with a humidity of 70% and a temperature of 40 °C for 48 hours, and the carrier layer is peeled off after curing.

[0057] In step (3), a solventless laminator is used in the coating and lamination processes, and the coating and lamination speeds are 150 m / min. The glue tank and transfer roller of the solventless laminator are preheated to 85 °C.

[0058] The obtained high-barrier paper with heat-sealing performance includes, in sequence, the paper, the adhesive layer, the vapor deposition layer, and the heat-sealable release layer. The vapor deposition layer is a silicon oxide barrier layer vapor-deposited on one side of the heat-sealable release layer. The vapor deposition layer is laminated on one side of the paper through the adhesive layer, and the heat-sealable release layer has heat-sealing performance and easy peelability.

[0059] Experimental example: After the high-barrier paper of Examples 1-3 is manufactured, samples are taken and the oxygen transmission rate is measured according to the national standard GB / T 19789-2021 Packaging Materials - Plastics Films and Sheeting - Determination of Oxygen Transmission Rate - Coulometric Detection Method, the water vapor transmission rate is measured according to the national standard GB / T 26253-2010 Plastics Films and Sheeting - Determination of Water Vapor Transmission Rate - Infrared Detection Method, and the heat seal strength is measured according to the standard QB / T 2358-1998 Test Method for Heat Seal Strength of Plastic Film Packaging Bags.

[0060] The test results of each sample are shown in Table 1 below.

[0061] Table 1: Project Example 1 Example 2 Example 3 Hot sealing strength N / 15mm 4.8 5.1 5.6 <![CDATA[Oxygen transmission rate cm 3 / (m 2 ·24h·0.1MPa)]]> 1.12 0.71 0.52 <![CDATA[Water vapor transmission rate g / m 2 .d]]> 3.36 0.14 0.24 As can be seen from Table 1, the high-barrier paper of Examples 1-3 of the present invention has excellent water barrier performance and oxygen barrier performance, with high barrier properties; and has excellent heat seal function. Among them, aluminum oxide is vapor-deposited in Example 1, and silicon oxide is vapor-deposited in Examples 2 and 3. The barrier property of the silicon oxide barrier layer is higher than that of the aluminum oxide barrier layer.

[0062] II. Comparison of Heat Seal Strength The heat seal strengths of PE-coated paper (whose heat seal layer is a PE film layer) and PLA-coated paper (whose heat seal layer is a PLA film layer) are tested, and the test results are shown in Table 2 below.

[0063] Table 2: Project PE coated paper PLA coated paper Hot sealing strength N / 15mm 4.2 3.8 As can be seen from Table 2, the heat seal performance of the heat-sealable release layer in the high-barrier paper of Examples 1-3 is comparable to that of plastic films.

[0064] III. Peelability of the Heat-Separable Release Layer During the production of the high-barrier paper of Examples 1-3, after step (1) is cured, samples are taken to peel off the covering film (non-corona-treated OPP film), and the peel strength between the release layer and the OPP film is tested according to the method of the national standard GB / T 2792-2014 Test Method for Peel Strength of Adhesive Tapes, and the coating transfer situation (release performance) is observed.

[0065] During the production of the high-barrier paper of Examples 1-3, after step (3) the composite layer material is compounded with the paper, wound up and cured, samples are taken to peel off the carrier layer (non-corona-treated PET film), and the peel strength between the release layer and the PET film is tested according to the method of the national standard GB / T 2792-2014 Test Method for Peel Strength of Adhesive Tapes, and the coating transfer situation (release performance) is observed.

[0066] The test results are shown in Table 3 below.

[0067] Table 3: Project Example 1 Example 2 Example 3 OPP release performance OPP completely no coating residue OPP completely no coating residue OPP completely no coating residue OPP peel strength N / 25mm 0.35 0.41 0.37 PET release performance PET completely no coating residue PET completely no coating residue PET completely no coating residue PET peel strength N / 25mm 0.77 0.91 0.83 The above test results show that after the coating of the heat-sealable release layer coating of the present invention is cured, the OPP peel force is less than the peel force for PET. It is relatively easy to first peel and recover the OPP film, and then peel and recover the PET carrier layer. Moreover, the heat-sealable release layer has good release performance for both the OPP film and the PET film, and there is no coating residue at all.

[0068] Comparative Example 1: In the preparation method of the barrier paper of Comparative Example 1, in step (3), a commercially available moisture-curing transfer adhesive (Xinyuan D5-1) was used to replace the solvent-free moisture-curing transfer adhesive in Example 1, and other technical features were the same as those in Example 1.

[0069] The barrier property of the barrier paper obtained in Comparative Example 1 was detected, and the test results are shown in Table 4 below. When a commercially available moisture-curing transfer adhesive (such as Xinyuan D5-1) was used for the adhesive layer, the obtained barrier paper also had a relatively high barrier property, but its barrier property was slightly lower than that of Example 1.

[0070] Table 4: Project Comparative Example 1 <![CDATA[Oxygen transmission rate cm 3 / (m 2 ·24h·0.1MPa)]]> 1.30 <![CDATA[Water vapor transmission rate g / m 2 .d]]> 3.89

Claims

1. A high-barrier paper with heat-sealing performance, characterized in that It includes a paper, an adhesive layer, a vapor deposition layer, and a heat-sealable release layer arranged in sequence. The vapor deposition layer is a silicon oxide or aluminum oxide barrier layer vapor-deposited on one side of the heat-sealable release layer. The vapor deposition layer is compounded on one side of the paper through the adhesive layer. The heat-sealable release layer has heat-sealing performance and easy peelability.

2. The preparation method of the high-barrier paper with heat-sealing performance according to claim 1, characterized in that It includes the following steps: (1) Manufacturing the heat-sealable release film Using a non-corona-treated PET film as the carrier layer, a polyurethane coating is coated on the carrier layer with a polyurethane coating material. After the polyurethane coating is cured, a heat-sealable release layer with heat-sealing performance and capable of peeling from the carrier layer is formed; (2) Manufacturing the vapor deposition layer A layer of aluminum oxide or silicon oxide is vacuum vapor-deposited on the heat-sealable release layer to form a vapor deposition layer, that is, an aluminum oxide or silicon oxide barrier layer, to obtain a composite layer material; (3) Manufacturing the high-barrier paper An adhesive layer is coated on one side of the paper, and then the composite layer material obtained in step (2) is compounded with the paper. The vapor deposition layer in the composite layer material is bonded to one side of the paper through the adhesive layer; then the carrier layer is peeled off to obtain the required high-barrier paper with heat-sealing performance.

3. The preparation method of the high-barrier paper with heat-sealing performance according to claim 2, wherein: In step (1), after coating the polyurethane coating, a cover film is compounded on the polyurethane coating to form a composite film and wound up. Then, the composite film roll is placed in an environment with a humidity less than 40% and a temperature of 30 - 50 °C for aging for 24 - 72 hours; after aging, the cover film is peeled off and recovered, that is, a heat-sealable release layer is formed on the carrier layer.

4. The preparation method of the high-barrier paper with heat-sealing performance according to claim 3, wherein: The cover film uses a non-corona-treated OPP film.

5. The preparation method of the high-barrier paper with heat-sealing performance according to claim 2, wherein: In step (1), the coating amount of the polyurethane coating is 3 - 8 g / m 2 ; In step (2), the thickness of the vapor deposition layer is 5 - 50 nm; In step (3), after the composite layer material is compounded with the paper, it is wound up, and then aged for 24 - 72 hours in an environment with a humidity of 60 - 80% and a temperature of 30 - 50 °C. After aging, the carrier layer is peeled off; In step (3), the coating amount of the adhesive layer is 2-8 g / m 2 .

6. The preparation method of the high-barrier paper with heat-sealing performance according to claim 2, wherein The polyurethane coating material used in step (1) includes component A and component B; Component A is made of raw materials with the following weight ratios: isophorone diisocyanate 10 - 20%, hexamethylene diisocyanate 20 - 50%, 1,4-cyclohexane diisocyanate 0 - 50%, cyclohexane dimethylene diisocyanate 0 - 40%, norbornane diisocyanate 0 - 30%; Component B is made of raw materials with the following weight ratios: dimer acid polyester diol 30 - 60%, polyetheramine 15 - 30%, polyaspartate 15 - 30%, dihydroxy polydimethylsiloxane 1 - 5%, silane coupling agent 1 - 5%; The ratio of component A and component B is determined according to an R value of 1.02 - 1.10, where the R value is the molar ratio of the total isocyanate groups to the total hydroxyl groups of component A and component B.

7. The preparation method of the high-barrier paper with heat-sealing performance according to claim 6, wherein: The component A is made of the following raw materials in weight ratio: 10-20% isophorone diisocyanate, 20-50% hexamethylene diisocyanate, 0.2-20% 1,4-cyclohexane diisocyanate, 0.2-20% cyclohexane dimethylene diisocyanate, and 0.2-20% norbornane diisocyanate; The molecular weight of the dimer acid polyester diol is 2000-2500, and the hydroxyl value is 35-45; the molecular weight of the polyether amine is 400-1000; the molecular weight of the polyaspartic acid ester is 400-600; and the molecular weight of the dihydroxy polydimethylsiloxane is 500-2000.

8. The preparation method of the high-barrier paper with heat-sealing performance according to claim 6 or 7, characterized in that The preparation method of the polyurethane coating comprises the following steps: (1a) Preparation of component A (1a-1) The following raw materials are prepared by weight: 10-20% of isophorone diisocyanate, 20-50% of hexamethylene diisocyanate, 0-50% of 1,4-cyclohexane diisocyanate, 0-40% of cyclohexane dimethylene diisocyanate, and 0-30% of norbornane diisocyanate; (1a-2) mixing the isophorone diisocyanate, hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, cyclohexane dimethylene diisocyanate and norbornane diisocyanate prepared in step (1a-1) to obtain component A for standby use; (2a) Preparation of component B (2a-1) The following raw materials are prepared by weight: 30-60% of dimer acid polyester diol, 15-30% of polyether amine, 15-30% of polyaspartic acid ester, 1-5% of dihydroxy polydimethylsiloxane, and 1-5% of silane coupling agent; (2a-2) uniformly mixing the dimer acid polyester diol, polyetheramine, polyaspartic acid ester, dihydroxy polydimethylsiloxane and silane coupling agent prepared in step (2a-1) to obtain component B for standby use; (3a) Preparation of polyurethane coatings Determine the ratio of component A to component B according to the R value of 1.02-1.10, mix component A and component B evenly to obtain the desired polyurethane coating.

9. The method for preparing high barrier paper with heat-sealing properties according to claim 2, characterized in that: The adhesive used in step (3) is a solvent-free moisture-curing transfer adhesive, which is made of the following raw materials in a weight ratio: 30-65% of dimer acid polyester diol, 5-20% of pentaerythritol polyoxypropylene tetraol, 5-25% of polyneopentyl terephthalate diol, 10-30% of diphenylmethane diisocyanate, and 0.2-1% of bismorpholinyl diethyl ether.

10. The preparation method of the high-barrier paper with heat-sealing performance according to claim 9, characterized in that The preparation method of the solvent-free moisture-curing transfer adhesive comprises the following steps in sequence: (1b) The following raw materials are prepared by weight: 30-65% of dimer acid polyester diol, 5-20% of pentaerythritol polyoxypropylene tetraol, 5-25% of polyneopentyl terephthalate diol, 10-30% of diphenylmethane diisocyanate, and 0.2-1% of bismorpholinyl diethyl ether; (2b) Add the dimer acid polyester diol, pentaerythritol polyoxypropylene tetrol, and neopentyl glycol poly(terephthalate) diol prepared in step (1b) to the reaction kettle, and then heat the materials in the reaction kettle to 105 - 120 °C. Pump water for 1 - 2 hours under a vacuum of -(6 - 10)×10 -4 MPa; (3b) cooling the contents of the reaction vessel to below 50°C, adding diphenylmethane diisocyanate, and then reacting at 75-85°C for 2-4 hours; (4b) Cool down the materials in the reactor to 40 - 60 °C, then add bis(morpholinyl)diethyl ether and stir evenly to obtain a solvent-free wet-curing transfer adhesive, which is sealed for standby.