A blue-black polyurethane adhesive and its preparation method and application

Abstract

The invention provides a blue-black polyurethane adhesive and a preparation method thereof. The blue-black polyurethane adhesive comprises 10-20 parts of an organic blue-black paste, 100 parts of a polyol, 10-20 parts of a curing agent, and 50-100 parts of a first organic solvent by weight. The organic blue-black paste is prepared by dissolving a molecular-level organic dye in a second organic solvent, and the molecular-level organic dye is an azine derivative. The blue-black polyurethane adhesive can reduce production costs and construction difficulties while ensuring the original performance of a lithium-ion battery aluminum-plastic film, thereby improving economic benefits. The invention also provides an application of the blue-black polyurethane adhesive in a lithium battery aluminum-plastic film. The blue-black adhesive is used for bonding between a nylon layer and an aluminum foil layer to obtain a lithium battery aluminum-plastic film, which has a uniform and elegant appearance, good modification and anti-counterfeiting effects, and solves the problems of difficult control of the production process of a traditional inorganic black adhesive coloring aluminum-plastic film, low peel strength, and poor resistance to high temperature, high humidity, and boiling.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum-plastic films for lithium-ion batteries, and in particular to a blue-black polyurethane adhesive and a preparation method and application thereof. Background Art

[0002] Soft-pack lithium batteries are widely used in the 3C and power energy storage fields. The existing aluminum-plastic film is mainly composed of transparent cast polypropylene film, transparent polyamide fiber, transparent adhesive and aluminum foil. Therefore, from the appearance, the aluminum-plastic film shows the color of the aluminum foil itself. Therefore, when the color of the text representing the product information printed on the surface of the aluminum-plastic film is white or other light colors, its appearance prominence is poor, making the appearance design of the aluminum-plastic film not rich enough. In order to take into account the prominence of the text of the aluminum-plastic film product and the variability of the text color, the black aluminum-plastic film came into being.

[0003] At present, the black aluminum-plastic film for lithium-ion batteries is mainly colored by printing ink on the nylon layer. It is difficult for the printing ink coating and the polymer coating to achieve a strong bonding effect, but it reduces the bonding strength between the nylon layer and the aluminum foil, and the high temperature resistance and boiling resistance are poor. Chinese patent CN 114551885 A discloses a black adhesive, which achieves the black effect by introducing carbon black into the adhesive, but the carbon black always exists in the adhesive system in the form of inorganic solid particles, which has a great influence on the uniformity of coloring and the bonding strength of the adhesive, and the preparation process of the carbon black slurry is complicated and the process control is difficult. Chinese patent CN 106003918A discloses a method for preparing a black aluminum-plastic film, which prepares a black nylon film by co-casting a black masterbatch and polyamide to prepare a black aluminum-plastic film. This method has too high process difficulty and cost, and the product performance and consistency are difficult to guarantee. There are no mature products on the market.

[0004] Therefore, one of the main research directions that technicians in this field have been committed to is to give the outer layer of the aluminum-plastic film a color while ensuring the performance of the aluminum-plastic film and reducing the production cost. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is to provide a blue-black polyurethane adhesive and a preparation method and application thereof, which can reduce the production cost and construction difficulty while ensuring the original performance of the aluminum-plastic film of the lithium-ion battery, and improve the economic benefits.

[0006] To achieve the above object, the present invention provides a blue-black polyurethane adhesive, which comprises, by weight:

[0007]

[0008] The organic blue-black paste is prepared by dissolving a molecular-level organic dye in a second organic solvent, and the molecular-level organic dye is an azine derivative.

[0009] Compared with the prior art, the blue-black polyurethane adhesive of the present invention is colored with molecular-level organic pigments. Because of their excellent compatibility with the adhesive system, the pigments can be evenly dissolved in the adhesive system without the need for professional dispersing equipment, thus solving the problem of complex configuration and difficult preservation of inorganic colorants, and will not affect the performance of the adhesive.

[0010] In some embodiments, the weight ratio of the molecular-grade organic dye to the second organic solvent is 1-5:5. By way of example, the weight ratio of the molecular-grade organic dye to the second organic solvent may be, but is not limited to, 1:5, 2:5, 3:5, 4:5, 5:5. The added amount and type of the molecular-grade organic dye vary, and the color presented varies. The ratio can be adjusted according to the color presented.

[0011] In some embodiments, the azine derivative is selected from at least one of Solvent Black 1, Solvent Black 3, Solvent Black 5, Solvent Black 7, Solvent Black 17, and Solvent Black 27.

[0012] In some embodiments, the polyol is selected from polyethers, polyesters or polyolefins and has a functionality of 2-3.

[0013] In some embodiments, the isocyanate curing agent is selected from an aliphatic curing agent or an aromatic isocyanate prepolymer curing agent.

[0014] In some embodiments, the isocyanate curing agent is selected from at least one of hexamethylene diisocyanate prepolymer, isophorone diisocyanate prepolymer, diphenylmethane diisocyanate prepolymer, or toluene diisocyanate prepolymer.

[0015] In some embodiments, the first organic solvent is selected from at least one of ethyl acetate, acetone, butanone, and toluene.

[0016] In some embodiments, the second organic solvent is selected from at least one of ethyl acetate, acetone, butanone, and toluene.

[0017] Accordingly, the present invention also provides a method for preparing a blue-black polyurethane adhesive, comprising the steps of:

[0018] (1) dissolving one or more molecular-level organic dyes into a second organic solvent and diluting the mixture to a preset concentration according to the desired color to obtain an organic blue-black slurry;

[0019] (2) weighing an organic blue-black slurry, a polyol, a curing agent and a first organic solvent according to a formula, stirring and mixing, and obtaining a blue-black polyurethane adhesive.

[0020] Correspondingly, the present invention also provides a blue-black polyurethane adhesive prepared by the preparation method of the above blue-black polyurethane adhesive or the use of the above blue-black polyurethane adhesive in a lithium battery aluminum-plastic film.

[0021] In some embodiments, from top to bottom, the lithium battery aluminum-plastic film includes a nylon layer, an aluminum foil layer and a polypropylene layer. The blue-black adhesive is used to bond the nylon layer and the aluminum foil layer to prepare a lithium battery aluminum-plastic film, which is called a lithium battery blue-black aluminum-plastic film. The appearance is uniformly and elegantly colored, and it has good modification and anti-counterfeiting effects, which solves the problems of difficult production process control of traditional inorganic black adhesive colored aluminum-plastic film, low peel strength, and inability to resist high temperature, high humidity and boiling.

[0022] In some embodiments, the blue-black polyurethane adhesive is gravure coated on the aluminum foil / polypropylene semi-finished product, and after being dried in an oven, the nylon film and the aluminum foil are combined by heat pressing, and then cured. The coating amount is 5-11 g / m 2 The drying temperature is 100-130°C, the hot pressing temperature is 80-100°C, the pressure is 0.05-0.08MPa, the aging temperature is 55°-70°, and the aging time is 1-7 days to prepare the aluminum-plastic film finished product.

[0023] The beneficial effects of the present invention are:

[0024] (1) The blue-black polyurethane adhesive of the present invention uses molecular-grade organic dyes to color the polyurethane adhesive. The organic dyes can be completely dissolved in the polyurethane adhesive system, and the preparation process is simple. No additional dispersing aids are required, and no professional dispersing equipment is required for dispersing.

[0025] (2) Molecular-level dyes are completely dissolved in the adhesive system, which completely solves the compatibility problem caused by adding inorganic carbon black to traditional black adhesives, ensuring the reliability and consistency of product performance;

[0026] (3) Molecular-level organic dyes have good high-temperature resistance, and their decomposition temperature is above 250°, which is much higher than the normal operating temperature of aluminum-plastic film. Replacing the black printed film with blue-black polyurethane adhesive can not only improve the heat and moisture resistance of the finished blue-black aluminum-plastic film, but also make the production process convenient and simple, significantly improving the economic benefits of the product preparation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the dyeing mechanism of organic blue-black color paste (a) and inorganic filler (b).

[0028] Figure 2The schematic diagram is a structural diagram of a blue-black aluminum-plastic film prepared by using the blue-black polyurethane adhesive of the present invention. DETAILED DESCRIPTION

[0029] The following is a preferred implementation of the embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the embodiment of the present invention. These improvements and modifications are also considered to be within the scope of protection of the embodiment of the present invention.

[0030] Some of the raw materials and their sources in the examples are as follows:

[0031] Polyester polyol, Desmophen 1652, Covestro Polymers (China) Co., Ltd.

[0032] Aliphatic polyisocyanate, Desmodur 3300, Covestro Polymers (China) Co., Ltd.

[0033] Azine derivatives (Solvent Black 27), BASF Orasol X51, BASF

[0034] Nano carbon black, JQ1931, Hangzhou Zhongfucai New Materials Co., Ltd.

[0035] Example 1

[0036] A blue-black polyurethane adhesive, comprising, by weight:

[0037]

[0038] The preparation method of the blue-black polyurethane adhesive of the present embodiment is as follows:

[0039] (1) Dissolve 10 parts of BASF Orasol X51 in 10 parts of butanone to obtain an organic blue-black slurry;

[0040] (2) Add 20 parts of organic blue-black slurry, 100 parts of polyester polyol, and 10 parts of aliphatic polyisocyanate to 50 parts of butanone, stir and mix, and obtain a blue-black polyurethane adhesive.

[0041] Example 2

[0042] A blue-black polyurethane adhesive, comprising, by weight:

[0043]

[0044] The preparation method of the blue-black polyurethane adhesive of the present embodiment is as follows:

[0045] (1) Dissolve 10 parts of BASF Orasol X51 in 10 parts of butanone to obtain an organic blue-black slurry;

[0046] (2) Add 10 parts of organic blue-black slurry, 100 parts of polyester polyol, and 20 parts of aliphatic polyisocyanate to 80 parts of butanone, stir and mix, and obtain a blue-black polyurethane adhesive.

[0047] Example 3

[0048] A blue-black polyurethane adhesive, comprising, by weight:

[0049]

[0050] The preparation method of the blue-black polyurethane adhesive of the present embodiment is as follows:

[0051] (1) Dissolve 10 parts of BASF Orasol X51 in 20 parts of butanone to obtain an organic blue-black slurry;

[0052] (2) 15 parts of organic blue-black slurry, 100 parts of polyester polyol, and 15 parts of aliphatic polyisocyanate are added to 60 parts of butanone, and the mixture is stirred to obtain a blue-black polyurethane adhesive.

[0053] Comparative Example 1

[0054] A blue-black polyurethane adhesive, comprising, by weight:

[0055]

[0056] The preparation method of the blue-black polyurethane adhesive of the present embodiment is as follows:

[0057] (1) dissolving 10 parts of nano-scale carbon black into 10 parts of butanone to obtain a color paste;

[0058] (2) Add 20 parts of color paste, 100 parts of polyester polyol, and 10 parts of aliphatic polyisocyanate to 50 parts of butanone, stir and mix, and obtain a polyurethane adhesive.

[0059] Application Examples 1-3

[0060] The polyurethane adhesive obtained in Example 1-3 was coated on the aluminum foil / polypropylene semi-finished product by gravure coating, and after being dried in an oven, the nylon film and the aluminum foil were combined by hot pressing, and then subjected to aging treatment. The coating amount was 6g / m 2 , drying temperature is 130℃, hot pressing temperature is 80℃, pressure is 0.08MPa, aging temperature is 70℃, and aging time is 3 days.

[0061] Please refer to the obtained blue-black aluminum-plastic film for lithium batteries. Figure 2 , from top to bottom, it includes a nylon layer 1, a blue-black adhesive layer 2, an aluminum foil layer 3 and a polypropylene layer 4.

[0062] Application Example 4

[0063] The polyurethane adhesive obtained in Comparative Example 1 was coated on the aluminum foil / polypropylene semi-finished product by gravure coating, and after being dried in an oven, the nylon film and the aluminum foil were combined by hot pressing, and then subjected to aging treatment. The coating amount was 6g / m 2 , drying temperature is 130℃, hot pressing temperature is 80℃, pressure is 0.08MPa, aging temperature is 70℃, and aging time is 3 days.

[0064] Application Example 5

[0065] This application example is basically the same as application example 1, except that it is a black aluminum-plastic film prepared from a conventionally printed black nylon film, that is, a black aluminum-plastic film prepared by printing ink on the surface of a transparent nylon film. The rest is the same as application example 1 and will not be elaborated here.

[0066] Application Example 6

[0067] This application example is basically the same as application example 1, except that it is an ordinary colorless aluminum-plastic film prepared from a conventional ordinary nylon film, that is, a conventional aluminum-plastic film is prepared without adding color paste during the preparation process, which serves as a blank control group for performance. The rest is the same as application example 1 and will not be elaborated here.

[0068] Please refer to Figure 1 The present invention provides a schematic diagram of the dyeing mechanism of using an organic blue-black color paste and an inorganic filler (nanoscale carbon black) in Example 1 and Comparative Example 1, respectively. Figure 1 (b) It can be seen that the addition of inorganic fillers to the traditional black adhesive physically disperses them in the adhesive system, which always faces the compatibility problem between the inorganic fillers and the organic polymers. Figure 1 (a) It can be seen that the molecular-level dye is dissolved in the adhesive system, which avoids the compatibility problems faced by traditional inorganic fillers and ensures the consistency and stability of the product.

[0069] The aluminum-plastic films obtained in Application Examples 1-6 were subjected to performance tests as follows:

[0070] 1. The initial peel strength of aluminum foil / nylon was used to characterize the bonding strength of the interface between nylon and aluminum foil. The test results are shown in Table 1.

[0071] 2. The peel strength of aluminum foil / nylon treated in a double 85 oven at 85°C and 85%RH reflects its high temperature and high humidity resistance. The specific method is: take a 15mm wide sample and place it in a constant temperature and humidity box with environmental parameters of 85°C and 85%RH, take out two pieces at 0h, 4h, and 8h, peel off the nylon and aluminum foil, and use a universal tensile machine to test the peel strength. The distance between the upper and lower clamps is 50mm, and the tensile speed is 200mm / min. The test results are shown in Table 1.

[0072] 3. Delamination test, take a 75mm wide sample strip with a length equal to the width of the entire product, use a single-pit mold with a parameter of 120*150mm to punch a depth of 4.25mm, punch ten membrane shells for each group of samples, place them in a constant temperature and humidity chamber for 6 hours, and then observe the delamination at the edges and corners of the membrane shell. If at least one edge turns white, it proves that water vapor has entered the gap between the edges and corners of the membrane shell, indicating that delamination has occurred. If multiple edges turn white, it indicates that the delamination is serious. The test results are shown in Table 2.

[0073] Table 1 Performance test results

[0074]

[0075] As can be seen from the data in Table 1, the aluminum foil / nylon bonding strength and high temperature and high humidity resistance of the aluminum-plastic film in Application Examples 1-3 of the present invention are higher than those in Application Examples 4-5. This is mainly because the polyurethane adhesives used between the aluminum foil and nylon in the aluminum-plastic film are different. The polyurethane adhesives between the aluminum foil and nylon in the aluminum-plastic film in Application Examples 1-3 respectively use the blue-black polyurethane adhesives of Examples 1-3, including molecular-level organic dyes, which are evenly dispersed in the adhesive system after dissolution, and do not destroy the bonding of the adhesive on the aluminum foil-nylon interface. While Application Example 4 uses the polyurethane adhesive of Comparative Example 1, including inorganic carbon black, and the addition of inorganic carbon black hinders the entanglement of the adhesive molecular chain segments between nylon and aluminum foil, resulting in a decrease in the bonding force of the nylon-aluminum foil interface. The printing layer used in Application Example 5 reduces the adhesion of the adhesive to the nylon interface, thereby reducing the bonding force of the aluminum foil-nylon interface. The peeling force of Application Example 4-5 decreases because the addition of printing ink and inorganic fillers results in a loose interface, and water vapor enters the adhesive layer, resulting in a decrease in the peeling force.

[0076] It can also be seen from Table 1 that the aluminum foil / nylon bonding strength and high temperature and high humidity resistance of the aluminum-plastic film in Application Examples 1-3 are not much different from those in Application Example 6, indicating that the use of the blue-black polyurethane adhesive can ensure the original performance of the aluminum-plastic film for lithium-ion batteries.

[0077] Table 2 Layered test results

[0078] Layering Application Example 1 No whitening layer Application Example 2 No whitening layer Application Example 3 No whitening layer Application Example 4 Whitening and delamination at 4 corners Application Example 5 Whitening and delamination at 3 corners Application Example 6 No whitening layer

[0079] From the data in Table 2, it can be seen that the aluminum-plastic films in Application Examples 1-3 of the present invention have no whitening and delamination phenomenon, indicating that the interface bonding performance between nylon and aluminum foil is good, while delamination occurs in Application Examples 4-5, indicating that the interface bonding strength between nylon and aluminum foil has decreased.

[0080] In summary, the direct use of the organic blue-black adhesive of the present invention significantly improves the aluminum foil / nylon bonding strength of the aluminum-plastic film and the high temperature and high humidity resistance of the material, and has obvious advantages over conventional printed black aluminum-plastic film and inorganic carbon black aluminum-plastic film. In addition, the organic blue-black slurry does not require additional dispersion and modification during the preparation process, is easy to store, and has high economic efficiency during the production process.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention is described in detail with reference to the preferred embodiments, it is not limited to those listed in the embodiments. Those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. Application of a blue-black polyurethane adhesive in lithium battery aluminum-plastic film, characterized in that: The blue-black polyurethane adhesive comprises, by weight: The organic blue-black paste is prepared by dissolving a molecular-grade organic dye in a second organic solvent, the molecular-grade organic dye is solvent black 27, the weight ratio of the molecular-grade organic dye to the second organic solvent is 1-5:5, the first organic solvent is selected from butanone, and the second organic solvent is selected from butanone.

2. The application of the blue-black polyurethane adhesive in lithium battery aluminum-plastic film according to claim 1, characterized in that: The polyol is selected from polyether, polyester or polyolefin and has a functionality of 2-3.

3. Application of the blue-black polyurethane adhesive in lithium battery aluminum-plastic film according to claim 1, characterized in that: The curing agent is selected from aliphatic curing agents or aromatic isocyanate prepolymer curing agents.

4. The application of the blue-black polyurethane adhesive in the aluminum-plastic film of lithium batteries according to claim 1, characterized in that: The preparation of the blue-black polyurethane adhesive comprises the following steps: (1) dissolving one or more molecular-level organic dyes into a second organic solvent and diluting the mixture to a preset concentration according to the desired color to obtain an organic blue-black slurry; (2) According to the formula, an organic blue-black slurry, a polyol, a curing agent and a first organic solvent are weighed and mixed with stirring to obtain a blue-black polyurethane adhesive.

5. Application of the blue-black polyurethane adhesive in lithium battery aluminum-plastic film according to claim 1, characterized in that: The blue-black adhesive is used for bonding between the nylon layer and the aluminum foil layer.

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