An impact-resistant two-component polyurethane adhesive, its preparation method and application

Abstract

This invention provides an impact-resistant two-component polyurethane adhesive, its preparation method, and its application. The raw materials include polymeric polyols, vegetable oil polyols, acrylic-modified epoxy polymers, functional additives, and polyisocyanates. The two-component polyurethane adhesive prepared by this invention exhibits good toughness, good adhesion, good impact resistance, and deep-drawing resistance. It also demonstrates certain heat resistance and moisture-proof properties, making it suitable for use in aluminum-plastic films for lithium batteries.

Description

Technical Field

[0001] This invention relates to the technical field of C09J175 / 06, specifically to an impact-resistant two-component polyurethane adhesive, its preparation method, and its application. Background Technology

[0002] Aluminum-plastic film is a crucial component in soft-pack lithium batteries. The aluminum-plastic film, from the outside in, consists of a nylon layer, an adhesive layer, an aluminum film, another adhesive layer, and an inner liner. In this structure, the adhesive layer's bonding strength and heat resistance are critical to improving the overall performance of the aluminum-plastic film. In recent years, the deep-drawing resistance of aluminum-plastic film has also received attention and research. Chinese patent CN109679567B discloses a two-component adhesive for deep-drawing resistance in lithium battery aluminum-plastic film. The raw materials include a main agent and a curing agent. The main agent comprises 5-20 parts polyester resin, 3-9 parts nitrogen-modified phenolic epoxy resin, 3-9 parts modified epoxy resin, 1-5 parts polyether polyol, 1-5 parts polyol, 0.1-0.5 parts additives, and 52-80 parts solvent. While the adhesive obtained by this patent exhibits good deep-drawing resistance, its bonding strength needs improvement, especially in the actual application of the aluminum-plastic film in lithium batteries, where stronger bonding is required.

[0003] Based on this, this application proposes an impact-resistant two-component polyurethane adhesive, its preparation method and application. The prepared two-component polyurethane adhesive has better bonding ability and also has good deep-drawing resistance and heat resistance. Summary of the Invention

[0004] The first aspect of this invention discloses an impact-resistant two-component polyurethane adhesive, the raw materials of which include:

[0005] Component A: Polymer polyols, vegetable oil polyols, epoxy polymers, functional additives;

[0006] Component B: Polyisocyanate.

[0007] In a preferred embodiment, the raw materials for preparation, by weight, include:

[0008] Component A: 40-70 parts polymer polyol, 20-50 parts vegetable oil polyol, 0.1-10 parts epoxy polymer, 0.1-5 parts functional additives;

[0009] Component B: 50-70 parts of polyisocyanate.

[0010] In a preferred embodiment, the mixing weight ratio of component A and component B is (1-10):1, and more preferably, the mixing weight ratio of component A and component B is (1-5):1.

[0011] In a preferred embodiment, the mixing weight ratio of component A to component B is 3:1.

[0012] In a preferred embodiment, the polymeric polyol in component A is selected from at least one of polyoxypropylene ether polyol, polyoxyethylene ether polyol, polyester polyol, and polymeric polyol derivatives.

[0013] In a preferred embodiment, the polymeric polyol in component A is a compound of polyoxypropylene ether polyol and polyester polyol.

[0014] In a preferred embodiment, the weight ratio of the polyoxypropylene ether polyol to the polyester polyol is (2-5):1. More preferably, the weight ratio of the polyoxypropylene ether polyol to the polyester polyol is 2.5:1.

[0015] In a preferred embodiment, the hydroxyl value of the polyoxypropylene ether polyol is 20-80 mgKOH / g, and more preferably, the hydroxyl value of the polyoxypropylene ether polyol is 30-45 mgKOH / g. In this application, the polyoxypropylene ether polyol is polypropylene glycol, purchased from Haian Petrochemical Plant in Jiangsu Province, with a specification of PPG3000.

[0016] In a preferred embodiment, the polyester polyol is selected from aliphatic polyester polyols or aromatic / aliphatic copolyester polyols. More preferably, the polyester polyol is an aliphatic polyester polyol.

[0017] In a preferred embodiment, the aliphatic polyester polyol is selected from a compound of saturated and unsaturated aliphatic polyester polyols. More preferably, the weight ratio of the saturated to unsaturated aliphatic polyester polyol is (1-3):1, and even more preferably, the weight ratio is 3:1.

[0018] In a preferred embodiment, the saturated aliphatic polyester polyol is polyadipate polyol ester, and more preferably, the saturated aliphatic polyester polyol is polybutylene adipate ester.

[0019] In this application, the hydroxyl value of polybutylene adipate is 53-59 mgKOH / g, and the viscosity at 60°C is 1300 cps. It was purchased from Handafei Biotechnology Co., Ltd.

[0020] In a preferred embodiment, the unsaturated aliphatic polyester polyol is a polymer of fumaric acid and diethylene glycol.

[0021] In a preferred embodiment, the polymer of fumaric acid and diethylene glycol is prepared as follows: fumaric acid and diethylene glycol are added to a reactor, and under a nitrogen atmosphere, the temperature is raised to 150°C for 3 hours for esterification reaction. Then, the temperature is raised to 210°C for polymerization reaction to obtain the polymer of fumaric acid and diethylene glycol.

[0022] In this application, the average molecular weight of the obtained polymer of fumaric acid and diethylene glycol is 2800-2900; the hydroxyl value of the obtained polymer of fumaric acid and diethylene glycol is 38-42 mgKOH / g.

[0023] During the experiment, the applicant discovered that using a linear polymer polyol with ether bonds in the polyurethane adhesive prepared in this application can improve the toughness and impact resistance of the polyurethane adhesive through the rotatability and linear extensibility of the linear ether bonds.

[0024] In a preferred embodiment, the vegetable oil polyol is castor oil. More preferably, the castor oil is hydrogenated castor oil.

[0025] In a preferred embodiment, the epoxy polymer in component A is selected from at least one of acrylic acid-modified epoxy polymers, silicone-modified epoxy polymers, phenolic resin-modified epoxy polymers, and anhydride-modified epoxy polymers.

[0026] In a preferred embodiment, the epoxy polymer in component A is an acrylic acid-modified epoxy polymer.

[0027] In a preferred embodiment, the acrylic-modified epoxy polymer has a viscosity of 10,000-16,000 cps at 30°C and a functionality of 3. In this application, the acrylic-modified epoxy polymer is epoxidized soybean oil triacrylate, purchased from Boxin New Materials, model B-106.

[0028] Polyurethane adhesive is a commonly used adhesive in lithium-ion battery aluminum-plastic films, used to bond nylon layers and aluminum foil layers, or aluminum foil layers and inner liners. However, some existing polyurethane adhesives, after bonding nylon and aluminum foil layers, are prone to cracking and separation from the aluminum foil layer under external impact, resulting in insufficient deep-drawing performance. During experiments, the applicant discovered that adding an acrylic-modified epoxy polymer improves the compatibility of the acrylic-modified epoxy polymer with polymer polyols and vegetable oil polyols. Simultaneously, the introduced epoxy groups not only further improve the adhesion performance of the polyurethane adhesive to the aluminum foil in the aluminum-plastic film, but also allow for further polymerization during the polyisocyanate reaction. By increasing the density of reaction sites, the cohesive force of the polyurethane adhesive is enhanced, improving its toughness while reducing delamination between the polyurethane adhesive and the aluminum foil and nylon, thus improving the deep-drawing resistance of the aluminum-plastic film.

[0029] In a preferred embodiment, the functional additive in component A is selected from at least one of anti-hydrolysis agents, coupling agents, dispersants, thixotropic agents, defoamers, crosslinking agents, and catalysts.

[0030] In a preferred embodiment, the functional additives in component A are an anti-hydrolysis agent, a crosslinking agent, and a catalyst. More preferably, the weight ratio of the anti-hydrolysis agent, crosslinking agent, and catalyst is (0.1-0.5):5:(0.01-0.05).

[0031] In a preferred embodiment, the anti-hydrolysis agent is carbodiimide.

[0032] In a preferred embodiment, the crosslinking agent is selected from one or more of 1,4-butanediol, diethylene glycol, trimethylolpropane, 1,4-cyclohexanediol, and hydroquinone. More preferably, the crosslinking agent is trimethylolpropane.

[0033] In this application, the type of catalyst is not specifically limited, but stannous octoate is preferred.

[0034] In a preferred embodiment, component A, by weight, comprises 66 parts of polymeric polyol, 23.5 parts of vegetable oil polyol, 8.5 parts of epoxy polymer, and 2 parts of functional additives.

[0035] In a preferred embodiment, the polyisocyanate of component B is selected from one or more of diisocyanates and polyisocyanates.

[0036] In a preferred embodiment, the polyisocyanate is a diisocyanate, including at least one of terephthalic diisocyanate, isophthalic diisocyanate, toluene diisocyanate, dicyclohexylmethane diisocyanate, and diphenylmethane diisocyanate.

[0037] In a preferred embodiment, the diisocyanate is a compound of isophthalic diisocyanate and diphenylmethane diisocyanate. More preferably, the weight ratio of isophthalic diisocyanate to diphenylmethane diisocyanate is 1:(0.3-0.5).

[0038] More preferably, the weight ratio of isophthalic diisocyanate to diphenylmethane diisocyanate is 1:0.4. The heat resistance of the polyurethane adhesive can be improved by adding phenyl diisocyanate.

[0039] The second aspect of this invention provides a method for preparing an impact-resistant two-component polyurethane adhesive, comprising the following steps:

[0040] (1) After stirring and mixing the polymer polyol, vegetable oil polyol and epoxy polymer evenly, add the functional additives and mix to form component A.

[0041] (2) Mix component A and component B in a certain proportion to obtain a two-component polyurethane adhesive.

[0042] The third aspect of this invention proposes the application of an impact-resistant two-component polyurethane adhesive for bonding aluminum-plastic films in lithium batteries.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] 1. The polyurethane adhesive prepared by this invention, by using a polymer polyol with straight-chain ether bonds, can improve the toughness and impact resistance of the polyurethane adhesive through the rotatability and straight-chain extensibility of the straight-chain ether bonds.

[0045] 2. The polyurethane adhesive prepared by this invention incorporates epoxidized soybean oil triacrylate, as well as polymeric polyols such as a polymer of fumaric acid and diethylene glycol. Through addition reaction, the compatibility of the acrylic-modified epoxy polymer with polymeric polyols and vegetable oil polyols is improved, and the adhesion ability of the polyurethane adhesive to metal and nylon surfaces is also improved.

[0046] 3. The polyurethane adhesive prepared by this invention increases the reaction site density and enhances the cohesive strength of the polyurethane adhesive itself by reacting the polymer polyol with multiple active groups in component A, hydrogenated castor oil, epoxidized soybean oil triacrylate with component B polyisocyanate, thereby reducing the delamination and peeling of the polyurethane adhesive from aluminum foil and nylon and improving the deep-drawing resistance of aluminum-plastic film.

[0047] 4. The polyurethane adhesive prepared by this invention contains phenyl-containing polyisocyanate, which improves the heat resistance and moisture-proof effect of the polyurethane adhesive.

[0048] 5. The polyurethane adhesive prepared by this invention has good properties and is suitable for bonding aluminum-plastic films for lithium batteries. Detailed Implementation

[0049] Example 1

[0050] The first aspect of this embodiment proposes an impact-resistant two-component polyurethane adhesive, the raw materials of which include component A and component B. Component A, by weight, includes: 66 parts of polymeric polyol, 23.5 parts of hydrogenated castor oil, 8.5 parts of epoxidized soybean oil triacrylate, and 2 parts of functional additives; component B consists of 50 parts of isophthalic dimethyl diisocyanate and 20 parts of diphenylmethane diisocyanate.

[0051] The polymer polyols include polyoxypropylene ether polyols and polyester polyols in a weight ratio of 2.5:1.

[0052] The polyoxypropylene ether polyol is polypropylene glycol, purchased from Haian Petrochemical Plant in Jiangsu Province, with a specification of PPG3000 and a hydroxyl value of 30-45 mgKOH / g.

[0053] The polyester polyol is a compound of polybutylene adipate, fumaric acid, and diethylene glycol in a weight ratio of 3:1. The polybutylene adipate has a hydroxyl value of 53-59 mgKOH / g and a viscosity of 1300 cps at 60°C, and was purchased from Handafei Biotechnology Co., Ltd. The average molecular weight of fumaric acid and diethylene glycol is 2800-2900. The specific preparation method is as follows: 5.5 mol of fumaric acid and 6 mol of diethylene glycol are added to a reactor, and under a nitrogen atmosphere, the temperature is raised to 150°C for 3 hours for esterification. Then, the temperature is raised to 210°C for polymerization to obtain the polymer of fumaric acid and diethylene glycol.

[0054] The epoxidized soybean oil triacrylate was purchased from Boxin New Materials, model number B-106.

[0055] The functional additives are an anti-hydrolysis agent, a crosslinking agent, and a catalyst in a weight ratio of 0.22:5:0.03. The anti-hydrolysis agent is carbodiimide, the crosslinking agent is trimethylolpropane, and the catalyst is stannous octoate.

[0056] The second aspect of this embodiment proposes a method for preparing an impact-resistant two-component polyurethane adhesive, comprising the following steps:

[0057] (1) Mix polypropylene glycol, polybutylene adipate and the polymer of fumaric acid and diethylene glycol, heat to 65°C and stir evenly, then heat to 110°C to dehydrate, cool to 70°C, then add dehydrated and dried hydrogenated castor oil, epoxidized soybean oil and triacrylic acid, stir and mix evenly, then add functional additives and mix to form component A.

[0058] (2) Mix component A and component B in a weight ratio of 3:1 to obtain a two-component polyurethane adhesive.

[0059] Example 2

[0060] The first aspect of this embodiment proposes an impact-resistant two-component polyurethane adhesive, the raw materials of which include component A and component B. Component A, by weight, includes: 66 parts of polymeric polyol, 23.5 parts of hydrogenated castor oil, 8.5 parts of bisphenol A epoxy resin, and 2 parts of functional additives; component B consists of 50 parts of isophthalic diisocyanate and 20 parts of diphenylmethane diisocyanate.

[0061] The polymer polyols include polyoxypropylene ether polyols and polyester polyols in a weight ratio of 2.5:1.

[0062] The polyoxypropylene ether polyol is polypropylene glycol, purchased from Haian Petrochemical Plant in Jiangsu Province, with a specification of PPG3000 and a hydroxyl value of 30-45 mgKOH / g.

[0063] The polyester polyol is a compound of polybutylene adipate, fumaric acid, and diethylene glycol in a weight ratio of 3:1. The polybutylene adipate has a hydroxyl value of 53-59 mgKOH / g and a viscosity of 1300 cps at 60°C, and was purchased from Handafei Biotechnology Co., Ltd. The average molecular weight of fumaric acid and diethylene glycol is 2800-2900. The specific preparation method is as follows: 5.5 mol of fumaric acid and 6 mol of diethylene glycol are added to a reactor, and under a nitrogen atmosphere, the temperature is raised to 150°C for 3 hours for esterification. Then, the temperature is raised to 210°C for polymerization to obtain the polymer of fumaric acid and diethylene glycol.

[0064] The functional additives are an anti-hydrolysis agent, a crosslinking agent, and a catalyst in a weight ratio of 0.22:5:0.03. The anti-hydrolysis agent is carbodiimide, the crosslinking agent is trimethylolpropane, and the catalyst is stannous octoate.

[0065] The second aspect of this embodiment proposes a method for preparing an impact-resistant two-component polyurethane adhesive, comprising the following steps:

[0066] (1) Mix polypropylene glycol, polybutylene adipate and the polymer of fumaric acid and diethylene glycol, heat to 65°C and stir evenly, then heat to 110°C to dehydrate, cool to 70°C, then add dehydrated and dried hydrogenated castor oil and bisphenol A epoxy resin and stir evenly, then add functional additives and mix to form component A.

[0067] (2) Mix component A and component B in a weight ratio of 3:1 to obtain a two-component polyurethane adhesive.

[0068] Example 3

[0069] The first aspect of this embodiment proposes an impact-resistant two-component polyurethane adhesive, the raw materials of which include component A and component B. Component A, by weight, includes: 66 parts of polymeric polyol, 23.5 parts of hydrogenated castor oil, 8.5 parts of epoxidized soybean oil triacrylate, and 2 parts of functional additives; component B consists of 50 parts of isophthalic dimethyl diisocyanate and 20 parts of diphenylmethane diisocyanate.

[0070] The polymer polyols include polyoxypropylene ether polyols and polyester polyols in a weight ratio of 2.5:1.

[0071] The polyoxypropylene ether polyol is polypropylene glycol, purchased from Haian Petrochemical Plant in Jiangsu Province, with a specification of PPG3000 and a hydroxyl value of 30-45 mgKOH / g.

[0072] The polyester polyol is polybutylene adipate, which has a hydroxyl value of 53-59 mgKOH / g and a viscosity of 1300 cps at 60°C. It was purchased from Handafei Biotechnology Co., Ltd.

[0073] The epoxidized soybean oil triacrylate was purchased from Boxin New Materials, model number B-106.

[0074] The functional additives are an anti-hydrolysis agent, a crosslinking agent, and a catalyst in a weight ratio of 0.22:5:0.03. The anti-hydrolysis agent is carbodiimide, the crosslinking agent is trimethylolpropane, and the catalyst is stannous octoate.

[0075] The second aspect of this embodiment proposes a method for preparing an impact-resistant two-component polyurethane adhesive, comprising the following steps:

[0076] (1) Mix polypropylene glycol and polybutylene adipate and heat to 65°C and stir evenly. Then heat to 110°C to dehydrate and cool to 70°C. Then add dehydrated and dried hydrogenated castor oil and epoxidized soybean oil triacrylate and stir evenly. Then add functional additives and mix to form component A.

[0077] (2) Mix component A and component B in a weight ratio of 3:1 to obtain a two-component polyurethane adhesive.

[0078] Comparative Example 1

[0079] This comparative example provides an impact-resistant two-component polyurethane adhesive, the specific implementation of which is the same as in Example 1, except that component A does not contain epoxy polymer.

[0080] Comparative Example 2

[0081] This comparative example provides a two-component polyurethane adhesive with impact resistance. Its specific implementation is the same as that of Example 1. The difference from Example 1 is that the polyisocyanate in Component B is hexamethylene diisocyanate.

[0082] Performance Testing

[0083] The two-component polyurethane adhesives prepared in Examples 1-3 and Comparative Examples 1-2 were coated on the surface of the nylon layer, and then an aluminum foil layer was attached to form a NY / Al adhesive layer. The peel strength, heat resistance, and deep drawing ability of the prepared NY / Al adhesive layer were tested. The data are recorded in Table 1.

[0084] 1. Peel strength: Refer to GB / T 2790-1995.

[0085] 2. Heat resistance: The prepared NY / Al adhesive layer was placed in a double 85 environment for 100 hours, and the peel strength was detected according to GB / T 2790-1995.

[0086] 3. Deep drawing ability; The stamping die is 80mm * 40mm, and the maximum depth is 20mm. The impact pressure is 0.7 MPa. If the aluminum foil does not tear or break, or the aluminum-plastic film does not delaminate after continuously stamping the shell 20 times at a certain depth, it means that the NY / Al adhesive layer passes the test at this stamping depth. The maximum qualified impact depth of each sample is recorded as the deep drawing depth.

[0087] Table 1

[0088]

Claims

1. An impact resistant two-component polyurethane adhesive, characterized in that, The raw materials for preparation include: A component: polymer polyol, vegetable oil polyol, epoxy polymer, functional additive; B component: polyisocyanate; The raw materials for preparation include, by weight: A component: 40-70 parts of polymer polyol, 20-50 parts of vegetable oil polyol, 0.1-10 parts of epoxy polymer, 0.1-5 parts of functional additive; B component: 50-70 parts of polyisocyanate; The epoxy polymer in the A component is epoxy soybean oil triacrylic acid; The polymer polyol is a compounded material of polyoxypropylene ether polyol and polyester polyol, with a mass ratio of (2-5):1; The polyoxypropylene ether polyol is polypropylene glycol; The polyester polyol is a compounded material of polybutylene adipate and polymeric material of fumaric acid and diethylene glycol, with a weight ratio of 3:

1.

2. The two-component polyurethane adhesive according to claim 1, characterized in that, The mixing weight ratio of the A component and the B component is (1-10):

1.

3. The two-component polyurethane adhesive according to any one of claims 1-2, characterized in that, The functional additive in the A component is selected from at least one of coupling agent, dispersant, thixotropic agent and defoaming agent.

4. The two-component polyurethane adhesive according to any one of claims 1 to 2, characterized in that The polyisocyanate in the B component is selected from one or more of diisocyanate and polyisocyanate.

5. A process for the preparation of the two-component polyurethane adhesive according to any one of claims 1 to 2, characterized in that, The method includes the following steps: (1) mixing the polymer polyol, the vegetable oil polyol and the epoxy polymer uniformly, and then adding the functional additive to form the A component; (2) mixing the A component and the B component in proportion to obtain the two-component polyurethane adhesive.

6. Use of the two-component polyurethane glue according to any one of claims 1-2, characterized in that, The application is applied to the bonding of lithium battery aluminum plastic film.

Images