Glue with high solid content and low viscosity, preparation method and medicinal aluminum foil containing glue

Abstract

The invention relates to the field of adhesives for aluminum foils, and particularly discloses high-solid-content low-viscosity glue, a preparation method and a medicinal aluminum foil containing the glue. The high-solid-content and low-viscosity glue comprises 60-80 parts of polyester polyol, 1-2 parts of an auxiliary agent, 30-40 parts of ethyl acetate, 1-3 parts of a coated plasticizer, 1-2 parts of a coated tackifier, 1-5 parts of a flow promoter, 6-11 parts of an alcohol diluent, 0.2-0.5 part of an initiator and 15-20 parts of a curing agent. The preparation method comprises the following steps: uniformly mixing the polyester polyol and the acetic ether, heating and stirring, adding the alcohol diluent, continuously stirring, cooling to 30-40 DEG C, adding the auxiliary agent, the coating plasticizer, the coating tackifier and the flow promoter, and uniformly mixing to obtain a mixture A; uniformly mixing a curing agent and an initiator to obtain a mixture B; mixing to obtain glue; preparing medicinal aluminum foil from the glue; the glue is good in fluidity during use and high in bonding strength after curing, and the service life of the medicinal aluminum foil is prolonged.

Description

Technical Field

[0001] The present application relates to the field of adhesives for aluminum foil, and more specifically, to a high-solid-content, low-viscosity glue, a preparation method, and a medicinal aluminum foil containing the glue. Background Art

[0002] Medicinal aluminum foil is an aluminum foil layer used to package tablets. It is mainly made of aluminum foil and plastic. It has the advantages of moisture-proof and anti-oxidation. It protects the drugs from deterioration and shelf life. It also has good protective effects. During the transportation of drugs, it is not easy to affect the integrity and quality of the drugs due to external impact, extrusion and other problems.

[0003] Medicinal aluminum foil is generally made by bonding multiple layers, and polyurethane adhesives are often used for bonding. At present, in the preparation process of polyurethane adhesives, solvents account for a large proportion and are highly volatile, which can easily pollute the surrounding environment. If the solvent content is reduced, the viscosity of the polyurethane adhesive will increase, making it difficult to coat, and affecting the uniform flow of the polyurethane adhesive on the surface of each film layer.

[0004] Therefore, how to prepare a high-solid content, low-viscosity glue that has good fluidity when used and high bonding strength after curing, thereby extending the service life of the medicinal aluminum foil, is a problem to be solved. Summary of the invention

[0005] In order to prepare a high-solid content, low-viscosity glue, the glue has good fluidity when used and has high bonding strength after curing, thereby extending the service life of medicinal aluminum foil, the present application provides a high-solid content, low-viscosity glue, a preparation method and a medicinal aluminum foil containing the glue.

[0006] In the first aspect, the present application provides a high solid content and low viscosity glue, which adopts the following technical solution: A high-solid content and low-viscosity glue comprises the following raw materials in parts by weight: 60-80 parts of polyester polyol, 1-2 parts of auxiliary agent, 30-40 parts of ethyl acetate, 1-3 parts of coating plasticizer, 1-2 parts of coating tackifier, 1-5 parts of flow promoter, 6-11 parts of alcohol diluent, 0.2-0.5 parts of initiator and 15-20 parts of curing agent.

[0007] By adopting the above technical scheme, the dissolving effect of ethyl acetate on the reactants is combined with the diluting effect of the flow promoter and the alcohol diluent on the glue, so as to ensure that the glue has a lower viscosity and better fluidity, and the glue is evenly distributed on the surface of the aluminum foil and other film layers; in the process of temperature rise and curing, the coating plasticizer and the coating thickener cooperate with each other, and at a higher temperature, after the film layer is destroyed, the plasticizer and the thickener gradually flow out, thereby improving the bonding effect of the glue, facilitating the glue to adhere to the surface of the aluminum foil and other film layers, improving the bonding strength, and thus extending the service life of the prepared medicinal aluminum foil.

[0008] Preferably, the polyester polyol is prepared by mixing polyester polyol liquid with silicon dioxide whiskers and subjecting the mixture to ultrasonic dispersion treatment, and the mass ratio of the polyester polyol liquid to the silicon dioxide whiskers is 100:1-3.

[0009] By adopting the above technical scheme, some hydroxyl groups on the surface of silica whiskers are used to attract them into the polyester polyol molecular chains. In combination with ultrasonic dispersion treatment, the silica whiskers are convenient for cutting the polyester polyol molecular chains, reducing the viscosity of the polyester polyol, and making the glue have lower viscosity and better fluidity. In combination with the diversion effect of the silica whiskers, the glue is further promoted to be evenly distributed after being coated on the surface of the aluminum foil and other film layers.

[0010] After uniform coating, during the process of heating and curing the glue, the connection effect of the silica whiskers, combined with the cross-linking bonding effect of the polyester polyol and the curing agent, initiator, plasticizer, and tackifier, improves the bonding strength of the glue on the surface of the aluminum foil and other film layers, ensuring the structural stability of the medicinal aluminum foil.

[0011] Preferably, the coating plasticizer is composed of ethylene glycol diacetate and polycaprolactone coated aminosulfonic acid in a mass ratio of 1:0.5-1.

[0012] By adopting the above technical scheme, ethylene glycol diacetate and polycaprolactone coated aminosulfonic acid are matched, and the hydroxyl group and ester group in ethylene glycol diacetate are used to dilute the glue and adjust the viscosity of the glue; during the glue mixing process, the polycaprolactone coated aminosulfonic acid can be dispersed in the glue, and the aminosulfonic acid is not easily released, thereby ensuring that the glue has good fluidity on the surface of aluminum foil and other film layers, and can be evenly dispersed and spread on the surface of aluminum foil and other film layers.

[0013] During the curing process of the glue at elevated temperature, ethylene glycol diacetate can cross-link with polyester polyols and isocyanates to form new chemical bonds, thereby increasing the degree of cross-linking of the glue and thus increasing the bonding strength of the glue on the surface of the aluminum foil and other film layers. In addition, during the heating process of the glue, polycaprolactone gradually melts and gradually releases aminosulfonic acid. The presence of aminosulfonic acid can not only catalyze the reaction of polyester polyols and isocyanates, but also act as a chain extender to increase the molecular chain of short-chain polyester polyols and increase the bonding strength of the glue. At the same time, the sulfonic acid group in aminosulfonic acid can attract and connect with the hydroxyl group and other polar groups in hexanediol diacetate to build a connection network, thereby increasing the structural stability of the molecular chain and further increasing the bonding strength of the glue on the surface of the aluminum foil and other film layers.

[0014] The combination of hexanediol diacetate and polycaprolactone can improve the flexibility and water resistance of the glue, protect the aluminum foil bonded by the glue from being easily damaged by the external environment, and thus protect the medicines sealed in the medicinal aluminum foil from being easily affected by the outside world.

[0015] Preferably, the coated tackifier is composed of polycaprolactone coated water-white rosin resin and polycaprolactone coated EVA in a mass ratio of 1:0.2-0.5.

[0016] By adopting the above technical scheme, the polycaprolactone coated water-white rosin resin and the polycaprolactone coated EVA are matched. When the glue is applied to the surface of the aluminum foil and other film layers, the tackifier of the polycaprolactone coating is not easy to increase the viscosity of the glue, ensuring that the low viscosity and good fluidity of the glue are evenly distributed on the surface of the aluminum foil and other film layers. During the temperature rise and curing process, the polycaprolactone gradually melts to release the water-white rosin resin and EVA. The water-white rosin resin is soluble in ethanol. Under the action of the alcohol diluent, the water-white rosin resin is dissolved and dispersed in the glue, thereby improving the adhesion effect of the glue on the surface of the aluminum foil and other film layers. In addition, during the temperature rise and curing process, the EVA is also gradually melted, further increasing the viscosity of the glue near the EVA, further improving the adhesion effect of the glue on the surface of the aluminum foil and other film layers, and cooperating with the viscosity of the polycaprolactone after hot melting, the glue has a higher bonding strength on the surface of the aluminum foil and other film layers.

[0017] Preferably, the flow promoter is composed of pentaerythritol and methyl silicone oil in a mass ratio of 1:0.1-0.2.

[0018] By adopting the above technical scheme, pentaerythritol and methyl silicone oil are matched, pentaerythritol can evenly disperse polyester polyol, reduce the viscosity of glue, and ensure the flow effect of glue, while methyl silicone oil can lubricate and disperse silica whiskers to ensure that the glue is evenly coated on the surface of aluminum foil and other film layers; and pentaerythritol and methyl silicone oil can plasticize polyurethane molecular chains to improve the flexibility of glue; at the same time, methyl silicone oil, polycaprolactone, water-white rosin resin, and EVA are matched to further improve the water resistance of glue, ensuring that the glue has high bonding strength and good waterproof effect on medicinal aluminum foil.

[0019] Preferably, the alcohol diluent consists of ethanol and polyethylene glycol 400 in a mass ratio of 10:1-3.

[0020] By adopting the above technical scheme, ethanol and polyethylene glycol 400 are combined to reduce the viscosity of the glue, improve the fluidity of the glue, and ensure that the glue is evenly dispersed on the surface of the aluminum foil and other film layers. During the curing process of the glue, ethanol and polyethylene glycol 400 can be cross-linked with substances such as polyester polyols and isocyanates, and ethanol and polyethylene glycol 400 can be connected with substances such as ethylene glycol diacetate and aminosulfonic acid to increase the structural density of the internal connection network of the glue, thereby improving the bonding strength of the glue on the surface of the aluminum foil and other film layers.

[0021] Preferably, the initiator is di-tert-butyl peroxide.

[0022] By adopting the above technical scheme, di-tert-butyl peroxide is used as an initiator to initiate a polymerization reaction during the polyurethane synthesis process; di-tert-butyl peroxide can initiate a reaction between polyester polyol and isocyanate by decomposing and generating free radicals, thereby promoting the growth and cross-linking of polyurethane chains and improving the bonding strength of the glue on the surface of aluminum foil and other film layers; and di-tert-butyl peroxide can utilize the peroxide group to react with the unsaturated bonds in the polyester polyol to form a cross-linking structure, and this cross-linking structure can enhance the strength and durability of the polyurethane material, make it have better physical properties and thermal stability, and extend the service life of the glue on the medicinal aluminum foil.

[0023] Preferably, the auxiliary agent is composed of an antioxidant and an inhibitor in a mass ratio of 1:1-3.

[0024] By adopting the above technical scheme, the antioxidant improves the antioxidant effect of the glue during the preparation process and the application process to the aluminum foil; the inhibitor can control the curing rate of the glue, ensuring that the glue on the surface of the aluminum foil has higher flexibility and higher bonding strength after curing.

[0025] In a second aspect, the present application provides a method for preparing a high-solid-content, low-viscosity glue, using the following technical solution: A method for preparing a high-solid-content, low-viscosity glue, comprising the following steps: S1. Weigh polyester polyol and ethyl acetate and mix them evenly, then heat to 80-90°C and heat for 2-3h, then add alcohol diluent and continue mixing and stirring for 0.5-1h, cool to 30-40°C, add auxiliary agent, coating plasticizer, coating tackifier and flow promoter and mix and stir evenly to obtain mixture A; S2, mixing and stirring the curing agent and the initiator to obtain a mixture B; S3. Mix the mixture A and the mixture B and stir them evenly, and use them immediately after preparation to obtain glue.

[0026] By adopting the above technical scheme, the prepared glue has the advantages of high solid content and low viscosity. By utilizing the good fluidity of the glue, it can be evenly dispersed and attached to the surface of aluminum foil and other film layers. As the glue is heated and solidified, it is ensured that the glue has high bonding strength and stability on the surface of aluminum foil and other film layers.

[0027] In a third aspect, the present application provides a medicinal aluminum foil containing high solid content and low viscosity glue, which adopts the following technical solution: A medicinal aluminum foil containing high-solid content and low-viscosity glue is prepared by uniformly coating the glue on the surface of a nylon layer, and then laminating the aluminum foil layer. The surface of the aluminum foil layer is coated with glue again, and then laminating the PVC layer. The surface is cured at a temperature of 60-80°C for 2-4 hours to obtain the medicinal aluminum foil. By adopting the above technical scheme, the glue tightly bonds the nylon layer, the aluminum foil layer, and the PVC layer together, and the heating and curing temperature is limited to ensure that the glue has a high bonding strength after curing, thereby extending the service life of the medicinal aluminum foil.

[0028] In summary, this application has the following beneficial effects: 1. The dissolving effect of ethyl acetate on the reactants is combined with the dilution effect of the flow promoter and the alcohol diluent on the glue to ensure that the glue has a lower viscosity and better fluidity, so that the glue is evenly distributed on the surface of the aluminum foil and other film layers; during the temperature rise and curing process, the coating plasticizer and the coating tackifier cooperate with each other. At a higher temperature, after the film layer is destroyed, the plasticizer and the tackifier gradually flow out, which improves the bonding effect of the glue, facilitates the glue to adhere to the surface of the aluminum foil and other film layers, improves the bonding strength, and thus prolongs the service life of the prepared medicinal aluminum foil.

[0029] 2. During the curing process of the glue, ethylene glycol diacetate can cross-link with polyester polyols and isocyanates to form new chemical bonds, thereby increasing the degree of cross-linking of the glue, thereby increasing the bonding strength of the glue on the surface of aluminum foil and other film layers; and during the heating process of the glue, polycaprolactone gradually melts and gradually releases aminosulfonic acid. The presence of aminosulfonic acid can not only catalyze the reaction of polyester polyols and isocyanates, but also act as a chain extender to increase the molecular chain of short-chain polyester polyols and improve the bonding strength of the glue. At the same time, the sulfonic acid group in aminosulfonic acid can attract and connect with the hydroxyl group and other polar groups in hexanediol diacetate to build a connection network, improve the structural stability of the molecular chain, and further improve the bonding strength of the glue on the surface of aluminum foil and other film layers.

[0030] 3. The combination of hexanediol diacetate, polycaprolactone and water-white rosin resin can improve the water resistance of the glue, protect the aluminum foil bonded by the glue from being damaged by the external environment, and thus protect the medicines sealed in the medicinal aluminum foil from being easily affected by the outside world. DETAILED DESCRIPTION

[0031] The present application is further described in detail below with reference to the embodiments.

[0032] The following raw materials are all commercially available.

[0033] Preparation Example of Polyester Polyol Preparation Example 1: Polyester polyol is prepared by the following method: 2 kg of silicon dioxide whiskers were added to 100 kg of polyester polyol liquid, and the mixture was ultrasonically dispersed at 20 kHz for 10 minutes to obtain polyester polyol; the average length of the silicon dioxide whiskers was 1 μm and the average diameter was 10 nm.

[0034] Preparation Example 2: This preparation example differs from Preparation Example 1 in that: 1 kg of silicon dioxide whiskers was added to 100 kg of polyester polyol solution, and ultrasonic dispersion was performed at 20 kHz for 10 minutes to obtain polyester polyol.

[0035] Preparation Example 3: This preparation example differs from Preparation Example 1 in that: 3 kg of silicon dioxide whiskers were added to 100 kg of polyester polyol solution, and ultrasonic dispersion was performed at 20 kHz for 10 minutes to obtain polyester polyol.

[0036] Preparation Example of Polycaprolactone Coated Aminosulfonic Acid Preparation Example 4: Polycaprolactone coated aminosulfonic acid was prepared by the following method: The polycaprolactone was heated to 65°C for complete hot melting to obtain a polycaprolactone melt. 1 kg of the polycaprolactone melt was evenly sprayed on the surface of 1 kg of aminosulfonic acid. The average particle size of the aminosulfonic acid was 10 μm. After drying and dispersion, polycaprolactone-coated aminosulfonic acid was obtained. The polycaprolactone-coated aminosulfonic acid was sieved through a 600-mesh sieve.

[0037] Preparation Example of Polycaprolactone Coated Water-white Rosin Resin Preparation Example 5: Polycaprolactone coated water-white rosin resin was prepared by the following method: The polycaprolactone was heated to 65°C for complete hot melting to obtain a polycaprolactone melt. 1 kg of the polycaprolactone melt was evenly sprayed on the surface of 1 kg of water-white rosin resin. The average particle size of the water-white rosin resin was 10 μm. After drying and dispersion, a polycaprolactone-coated water-white rosin resin was obtained. The polycaprolactone-coated water-white rosin resin was sieved through a 600-mesh sieve.

[0038] Preparation Example of Polycaprolactone Coated EVA Preparation Example 6: Polycaprolactone coated EVA was prepared by the following method: The polycaprolactone was heated to 65°C for complete hot melting to obtain a polycaprolactone melt. 1 kg of the polycaprolactone melt was evenly sprayed on the surface of 1 kg of EVA. The average particle size of the EVA was 10 μm. After drying and dispersion, the polycaprolactone coated EVA was obtained. The polycaprolactone coated EVA was sieved through a 600-mesh sieve. Example

[0039] Example 1: A high solid content and low viscosity glue: 70kg of polyester polyol, 1.5kg of auxiliary agent, 35kg of ethyl acetate, 2kg of coating plasticizer, 1.5kg of coating tackifier, 3kg of flow promoter, 9kg of alcohol diluent, 0.3kg of initiator, and 18kg of curing agent; the polyester polyol adopts the polyester polyol prepared in Preparation Example 1; the auxiliary agent consists of an antioxidant and an inhibitor in a mass ratio of 1:2; the coating plasticizer consists of ethylene glycol diacetate in a mass ratio of 1:1 and polycaprolactone coated aminosulfonic acid prepared in Preparation Example 4; the coating tackifier consists of polycaprolactone coated water-white rosin resin prepared in Preparation Example 5 in a mass ratio of 1:0.5 and polycaprolactone coated EVA prepared in Preparation Example 6; the flow promoter consists of pentaerythritol and methyl silicone oil in a mass ratio of 1:0.2; the alcohol diluent consists of ethanol and polyethylene glycol 400 in a mass ratio of 10:2; the initiator is di-tert-butyl peroxide; and the curing agent is diisocyanate; The preparation method is as follows: S1. Weigh polyester polyol and ethyl acetate and mix them evenly, then heat to 85°C and heat for 2.5h, then add alcohol diluent and continue mixing and stirring for 1h, cool to 35°C, add auxiliary agent, coating plasticizer, coating tackifier and flow promoter and mix and stir evenly to obtain mixture A; S2, mixing and stirring the curing agent and the initiator to obtain a mixture B; S3. Mix the mixture A and the mixture B and stir them evenly, and use them immediately after preparation to obtain glue.

[0040] Embodiment 2: This embodiment differs from Embodiment 1 in that: 60kg of polyester polyol, 1kg of auxiliary agent, 30kg of ethyl acetate, 1kg of coating plasticizer, 1kg of coating tackifier, 1kg of flow promoter, 6kg of alcohol diluent, 0.2kg of initiator, and 15kg of curing agent; the polyester polyol adopts the polyester polyol prepared in Preparation Example 2; the auxiliary agent is composed of an antioxidant and an inhibitor in a mass ratio of 1:1; the coating plasticizer is composed of ethylene glycol diacetate in a mass ratio of 1:0.5 and polycaprolactone coated aminosulfonic acid prepared in Preparation Example 4; the coating tackifier is composed of polycaprolactone coated water-white rosin resin prepared in Preparation Example 5 in a mass ratio of 1:0.2 and polycaprolactone coated EVA prepared in Preparation 6; the flow promoter is composed of pentaerythritol and methyl silicone oil in a mass ratio of 1:0.1; the alcohol diluent is composed of ethanol and polyethylene glycol 400 in a mass ratio of 10:1; the initiator is di-tert-butyl peroxide; the curing agent is diisocyanate; The preparation method is as follows: S1. Weigh polyester polyol and ethyl acetate and mix them evenly, then heat to 80°C and heat for 3h, then add alcohol diluent and continue mixing and stirring for 0.5h, cool to 40°C, add auxiliary agent, coating plasticizer, coating tackifier and flow promoter and mix and stir evenly to obtain mixture A; S2, mixing and stirring the curing agent and the initiator to obtain a mixture B; S3. Mix the mixture A and the mixture B and stir them evenly, and use them immediately after preparation to obtain glue.

[0041] Embodiment 3: This embodiment differs from Embodiment 1 in that: 80kg of polyester polyol, 2kg of auxiliary agent, 40kg of ethyl acetate, 3kg of coating plasticizer, 2kg of coating tackifier, 5kg of flow promoter, 11kg of alcohol diluent, 0.5kg of initiator, and 20kg of curing agent; the polyester polyol adopts the polyester polyol prepared in Preparation Example 3; the auxiliary agent is composed of an antioxidant and an inhibitor in a mass ratio of 1:3; the coating plasticizer is composed of ethylene glycol diacetate and polycaprolactone coated aminosulfonic acid in a mass ratio of 1:1; the coating tackifier is composed of polycaprolactone coated water-white rosin resin and polycaprolactone coated EVA in a mass ratio of 1:0.5; the flow promoter is composed of pentaerythritol and methyl silicone oil in a mass ratio of 1:0.2; the alcohol diluent is composed of ethanol and polyethylene glycol 400 in a mass ratio of 10:3; the initiator is di-tert-butyl peroxide; and the curing agent is diisocyanate; The preparation method is as follows: S1. Weigh polyester polyol and ethyl acetate and mix them evenly, then heat to 90°C and heat for 2h, then add alcohol diluent and continue mixing and stirring for 1h, cool to 30°C, add auxiliary agent, coating plasticizer, coating tackifier and flow promoter and mix and stir evenly to obtain mixture A; S2, mixing and stirring the curing agent and the initiator to obtain a mixture B; S3. Mix the mixture A and the mixture B and stir them evenly, and use them immediately after preparation to obtain glue.

[0042] Embodiment 4: This embodiment differs from Embodiment 1 in that: The polyester polyol in the raw material is a common commercially available polyester polyol liquid, without adding silicon dioxide whiskers.

[0043] Embodiment 5: This embodiment differs from Embodiment 1 in that: The coating plasticizer in the raw materials does not contain polycaprolactone coated aminosulfonic acid.

[0044] Embodiment 6: This embodiment differs from Embodiment 1 in that: Hexanediol diacetate is not added as coating plasticizer in the raw materials.

[0045] Embodiment 7: This embodiment differs from Embodiment 1 in that: Polycaprolactone coated EVA is not added as coating thickener in the raw materials.

[0046] Embodiment 8: This embodiment differs from Embodiment 1 in that: No methyl silicone oil was added as flow promoter in the raw materials.

[0047] Comparative Example Comparative Example 1: The difference between this comparative example and Example 1 is that: In the raw materials, the polycaprolactone coated water-white rosin resin is replaced by the water-white rosin resin of the same mass, and the polycaprolactone coated EVA is replaced by the EVA of the same mass, that is, the tackifier is not coated.

[0048] Comparative Example 2: The difference between this comparative example and Example 1 is that: No flow promoter was added to the raw material.

[0049] Application Examples Application Example 1: A medicinal aluminum foil containing high solid content and low viscosity glue: The glue was evenly coated on the surface of the nylon layer, with 45 mL of glue per square meter of the nylon layer surface, and then the aluminum foil layer was attached. The glue was coated on the surface of the aluminum foil layer again, with 50 mL of glue per square meter of the aluminum foil layer surface, and then the PVC layer was attached. The glue was cured at 70°C for 3 hours to obtain a medicinal aluminum foil. The glue prepared in Example 1 was used.

[0050] Application Example 2: A medicinal aluminum foil containing high solid content and low viscosity glue: The glue was evenly coated on the surface of the nylon layer, with 45 mL of glue per square meter of the nylon layer surface, and then the aluminum foil layer was attached. The aluminum foil layer was coated with glue again, with 50 mL of glue per square meter of the aluminum foil layer surface, and then the PVC layer was attached. The glue was cured at 60°C for 4 hours to obtain a medicinal aluminum foil. The glue prepared in Example 2 was used.

[0051] Application Example 3: A medicinal aluminum foil containing high solid content and low viscosity glue: The glue was evenly coated on the surface of the nylon layer, with 45 mL of glue per square meter of the nylon layer surface, and then the aluminum foil layer was attached. The aluminum foil layer was coated with glue again, with 50 mL of glue per square meter of the aluminum foil layer surface, and then the PVC layer was attached. The glue was cured at 80°C for 2h to obtain a medicinal aluminum foil. The glue prepared in Example 3 was used.

[0052] Application Example 4-8: The difference from Application Example 1 is: The glues correspond to the glues prepared in Examples 4-8 respectively.

[0053] Comparative Application Examples Comparative Application Example 1-2: The difference from Application Example 1 is: The glues were respectively the glues prepared in Comparative Examples 1-2.

[0054] Performance testing 1. Viscosity detection Glue was prepared by the methods of Examples 1-4, 6, 8 and Comparative Examples 1-2 respectively, and its viscosity was tested by a viscometer and the data was recorded.

[0055] 2. Bond strength test The glue was prepared by the methods of Examples 1-3, 5, 7-8 and Comparative Application Example 1, and the 180° peeling force of the glue was tested with reference to GB / T2790, wherein the curing temperature of the glue was 70°C and the curing time was 3h, and the data was recorded; the greater the peeling force, the higher the bonding strength; The peeling force was tested at 10 locations respectively, and the difference between the maximum peeling force and the minimum peeling force was recorded. The smaller the difference, the more evenly the adhesive force of the glue was distributed.

[0056] 3. Water resistance test The medicinal aluminum foils were prepared by the methods of application examples 1-3 and 5-8, respectively. The medicinal aluminum foils were placed in water and soaked for 24 hours. The medicinal aluminum foils were taken out and observed to see whether there was a delamination problem. The glues of examples 1-3, 5-6 and 8 were rated. The better the water resistance of the glue, the less likely it is that the medicinal aluminum foil will have a delamination problem. The rating standard is as follows: Delamination area ≤ 1 cm 2 , level 1; 1cm2 <Layer area≤5cm 2 , Level 2; 5cm 2 <Layer area≤20cm 2 , level 3; 20cm 2 <Layer area ≤50cm 2 , Level 4; 50cm 2 <Layered area, level 5.

[0057] 4. Mechanical properties testing The methods of Examples 1-3, 5, and 7-8 were used to prepare glue, respectively. The elongation at break of the coating formed by the glue was tested with reference to GB / T528, and the data were recorded.

[0058] Table 1 Performance test table (“ / ” in the table means that the corresponding embodiment or comparative example did not test the item, so there is no data) It can be seen from Examples 1-3 and Table 1 that the glue prepared in the present application has low viscosity, good fluidity, and high bonding effect, can be evenly distributed on the surface of aluminum foil and other film layers, and has good flexibility, which can extend the service life of medicinal aluminum foil.

[0059] Combining Example 1 and Examples 4-8 and Table 1, it can be seen that the polyester polyol in the raw material of Example 4 is a common commercially available polyester polyol liquid, and no silica whiskers are added. Compared with Example 1, the viscosity of the glue prepared in Example 4 is higher than that in Example 1; this indicates that the addition of silica whiskers can cut off the molecular chains of the polyester polyol, help to reduce the viscosity of the glue during the coating process, improve the flow effect, and ensure the uniformity of the coated glue.

[0060] In Example 5, the coated plasticizer in the raw materials does not contain polycaprolactone coated aminosulfonic acid. Compared with Example 1, the peeling force of the glue prepared in Example 5 is lower than that in Example 1, and the elongation at break is lower than that in Example 1; this indicates that during the curing process of the glue, the polycaprolactone gradually melts and gradually releases aminosulfonic acid. The presence of aminosulfonic acid can not only catalyze the reaction of polyester polyols and isocyanates, but also act as a chain extender to increase the molecular chains of short-chain polyester polyols and improve the bonding strength of the glue. At the same time, the sulfonic acid groups in aminosulfonic acid can attract and connect with the hydroxyl groups and other polar groups in hexanediol diacetate to build a connection network, thereby improving the structural stability of the molecular chain and further improving the bonding strength of the glue on the surfaces of aluminum foil and other film layers.

[0061] In Example 6, no hexanediol diacetate was added as the coating plasticizer in the raw materials. Compared with Example 1, the viscosity of the glue prepared in Example 6 was higher than that in Example 1, and the water resistance was worse than that in Example 1. This indicates that hexanediol diacetate can adjust the viscosity of the glue and, in combination with polycaprolactone, improve the water resistance of the glue after curing, thereby ensuring the service life of the medicinal aluminum foil.

[0062] In Example 7, no polycaprolactone-coated EVA was added as the coating thickener in the raw materials. Compared with Example 1, the glue prepared in Example 7 had lower peeling force and lower elongation at break than Example 1, indicating that hot-melt bonding of polycaprolactone and EVA during the curing process of the glue improved the bonding strength of the glue, and polycaprolactone and EVA had good waterproof effect, which could improve the water resistance of the glue after curing.

[0063] In Example 8, no methyl silicone oil was added as the flow promoter in the raw materials. Compared with Example 1, the glue prepared in Example 8 had higher viscosity than that in Example 1, lower peeling force than that in Example 1, and a difference greater than that in Example 1. The water resistance was worse than that in Example 1, and the elongation at break was lower than that in Example 1. This indicated that methyl silicone oil could improve the fluidity of the glue, cross-link the silica whiskers, improve the bonding strength and uniformity of the glue, and at the same time, methyl silicone oil had good water resistance, could also improve the flexibility of the glue after curing, and extend the service life of the medicinal aluminum foil.

[0064] Combining Example 1 and Comparative Examples 1-2 and Table 1, it can be seen that in the raw materials of Comparative Example 1, the water-white rosin resin of the same mass is used to replace the polycaprolactone coated water-white rosin resin, and the polycaprolactone coated EVA is replaced with the same mass of EVA, that is, the tackifier is not coated. Compared with Example 1, the viscosity of the glue prepared in Comparative Example 1 is higher than that of Example 1, and the peeling force is lower than that of Example 1; it indicates that the coated water-white rosin resin and EVA are not easy to increase the viscosity of the glue during the glue coating process, affecting the coating uniformity, and the bonding strength of the glue can be improved in the temperature rising and curing stage, and the polycaprolactone hot melt has a certain viscosity, which can improve the bonding strength of the glue on the aluminum foil and other film surfaces after curing, and extend the service life of the medicinal aluminum foil.

[0065] No flow promoter was added to the raw materials of Comparative Example 2. Compared with Example 1, the viscosity of the glue prepared in Comparative Example 2 was higher than that in Example 1. This indicates that the addition of the flow promoter can adjust the viscosity of the glue and ensure the fluidity of the glue. During the glue coating process, the glue has better flow dispersion and ensures the uniformity of glue bonding.

[0066] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A high solid content and low viscosity glue, characterized in that: The glue comprises the following raw materials in parts by weight: 60-80 parts of polyester polyol, 1-2 parts of auxiliary agent, 30-40 parts of ethyl acetate, 1-3 parts of coating plasticizer, 1-2 parts of coating tackifier, 1-5 parts of flow promoter, 6-11 parts of alcohol diluent, 0.2-0.5 parts of initiator and 15-20 parts of curing agent.

2. The high solid content and low viscosity glue according to claim 1, characterized in that: The polyester polyol is prepared by mixing polyester polyol liquid with silicon dioxide whiskers and then subjecting the mixture to ultrasonic dispersion treatment. The mass ratio of the polyester polyol liquid to the silicon dioxide whiskers is 100:1-3.

3. The high solid content and low viscosity glue according to claim 1, characterized in that: The coating plasticizer is composed of ethylene glycol diacetate and polycaprolactone coated aminosulfonic acid in a mass ratio of 1:0.5-1.

4. The high solid content and low viscosity glue according to claim 1, characterized in that: The coating tackifier is composed of polycaprolactone coated water-white rosin resin and polycaprolactone coated EVA in a mass ratio of 1:0.2-0.

5.

5. The high solid content and low viscosity glue according to claim 1, characterized in that: The flow promoter is composed of pentaerythritol and methyl silicone oil in a mass ratio of 1:0.1-0.

2.

6. The high solid content and low viscosity glue according to claim 1, characterized in that: The alcohol diluent consists of ethanol and polyethylene glycol 400 in a mass ratio of 10:1-3.

7. The high solid content and low viscosity glue according to claim 1, characterized in that: The initiator is di-tert-butyl peroxide.

8. The high solid content and low viscosity glue according to claim 1, characterized in that: The auxiliary agent consists of an antioxidant and an inhibitor in a mass ratio of 1:1-3.

9. The method for preparing a high-solid-content, low-viscosity glue according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Weigh polyester polyol and ethyl acetate and mix them evenly, then heat to 80-90°C and heat for 2-3h, then add alcohol diluent and continue mixing and stirring for 0.5-1h, cool to 30-40°C, add auxiliary agent, coating plasticizer, coating tackifier and flow promoter and mix and stir evenly to obtain mixture A; S2, mixing and stirring the curing agent and the initiator to obtain a mixture B; S3. Mix the mixture A and the mixture B and stir them evenly, and use them immediately after preparation to obtain glue.

10. A medicinal aluminum foil containing high solid content and low viscosity glue, characterized in that: The invention comprises a nylon layer, an aluminum foil layer and a glue layer located between the two, wherein the glue layer is prepared by curing glue at a temperature of 60-80°C; the glue is selected from the glue described in any one of claims 1-8 or the glue prepared by the preparation method of claim 9.

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