High-cohesiveness polyol polyurethane adhesive as well as preparation method and application thereof

Abstract

The invention provides a high-cohesiveness polyol polyurethane adhesive as well as a preparation method and application thereof, and relates to the technical field of adhesives. The adhesive comprises a component A and a component B. The component A comprises, by weight, 20-30 parts of polyol, 30-45 parts of boron nitride, 2-3 parts of an auxiliary agent and 5-8 parts of a catalyst. And the component B comprises the following components in parts by weight: 10-35 parts of polyurethane, 25-50 parts of nano silicon dioxide and 1-5 parts of auxiliaries. The high-cohesiveness polyol polyurethane adhesive disclosed by the invention not only has excellent performance on the traditional cohesive force, but also realizes comprehensive improvement in the aspects of thermal conductivity, mechanical strength, weather resistance, processability and the like.

Description

Technical Field

[0001] The invention relates to the technical field of adhesives, and in particular to a high-adhesive polyol polyurethane adhesive and a preparation method and application thereof. Background Art

[0002] With the development of modern industry, the performance requirements for adhesives are getting higher and higher. Especially in the fields of aerospace, automobile manufacturing, electronic equipment and construction, adhesives with high adhesion, weather resistance and mechanical strength are needed. Polyurethane adhesives have become one of the important materials in these fields due to their excellent properties, such as good elasticity, wear resistance, tear resistance and bonding strength. However, traditional polyurethane adhesives still have shortcomings in certain specific application conditions, such as stability under high temperature or extreme environments, and adhesion to special materials.

[0003] In order to overcome the above shortcomings and meet higher application requirements, researchers are committed to developing new polyurethane adhesive systems. As an important branch, polyol polyurethane adhesives can significantly improve the comprehensive performance of adhesives by adjusting the proportion of components in the formula and adding specific functional fillers. For example, boron nitride, as a highly efficient thermal conductive filler, can effectively improve the thermal conductivity of adhesives; nano-silica, due to its high specific surface area and excellent thickening effect, helps to improve the mechanical strength and aging resistance of adhesives. In addition, the selection of suitable catalysts is also crucial to controlling the reaction rate and ensuring the quality of the final product. Therefore, how to effectively integrate these functional ingredients into the polyurethane adhesive system and ensure good compatibility between the components, so as to achieve the purpose of improving the bonding performance of the adhesive, is still one of the main problems currently faced. Summary of the invention

[0004] In view of this, the present invention proposes a high-adhesive polyol polyurethane adhesive and a preparation method thereof, aiming to obtain a high-performance adhesive that performs well in a variety of application scenarios by optimizing the formulation composition and process parameters. The adhesive not only has excellent bonding properties, but also has good processing properties and long-term stability, and is suitable for a wide range of industrial applications.

[0005] In a first aspect, the present invention provides a high-adhesive polyol polyurethane adhesive, comprising component A and component B;

[0006] The component A comprises, by weight: 20 to 30 parts of polyol, 30 to 45 parts of boron nitride, 2 to 3 parts of auxiliary agent and 5 to 8 parts of catalyst;

[0007] The component B comprises, by weight, 10 to 35 parts of polyurethane, 25 to 50 parts of nano silicon dioxide and 1 to 5 parts of auxiliary agent.

[0008] Furthermore, the polyol is selected from polyester polyol and / or polycarbonate polyol.

[0009] Furthermore, the particle size of the boron nitride particles does not exceed 2 μm.

[0010] Furthermore, the catalyst is selected from one or more of organic tin catalysts and / or organic amine catalysts.

[0011] Furthermore, the auxiliary agent is selected from one or more of antioxidants, flame retardants or color pastes.

[0012] Furthermore, the particle size of the nano-silicon dioxide is 10 to 30 nm.

[0013] In a second aspect, the present invention provides a method for preparing the above-mentioned high-adhesive polyol polyurethane adhesive, comprising the following steps:

[0014] S1. Mix the polyol, boron nitride, additives and catalyst according to the mass fractions, heat and stir to obtain component A;

[0015] S2. Mix the polyurethane, nano-silicon dioxide and additives according to the weight ratio to obtain component B;

[0016] S3, mixing component A of step S1 with component B of step S2 to obtain a highly adhesive polyol polyurethane adhesive.

[0017] Furthermore, in step S2, the preparation of the polyurethane includes: mixing diphenylmethane isocyanate and polyol in a mass ratio of (1.1-1.3):1 to prepare the polyurethane.

[0018] In a third aspect, the present invention relates to the use of the above-mentioned high-adhesion polyol polyurethane adhesive in batteries.

[0019] The high-adhesive polyol polyurethane adhesive and the preparation method thereof provided by the present invention have the following beneficial effects compared with the prior art:

[0020] (1) The two-component high-adhesive polyol polyurethane adhesive prepared by the present invention, on the one hand, introduces boron nitride into component A, which is a highly efficient thermal conductive filler. Its fine particle size (no more than 2 μm) ensures that it can be evenly distributed in the adhesive system, which not only improves the thermal conductivity of the adhesive, but also helps to quickly disperse heat, avoid bonding failure caused by local overheating, and also enhances the mechanical strength; on the other hand, nano-silicon dioxide is introduced into component B, and its particle size range is between 10 and 30 nm, which can form a stable network structure in the adhesive, greatly improve the mechanical strength and hardness of the adhesive, and improve the aging resistance. Under the combined action of the above two fillers, the high-adhesive polyol polyurethane adhesive prepared by the present invention not only has good thermal conductivity and a longer service life, but also can maintain excellent stability in the face of extreme environmental conditions. In addition, nano-silicon dioxide also has a good thickening effect, which helps to adjust the working viscosity of the adhesive, making it easier to operate and apply during the construction process.

[0021] (2) The high-adhesive polyol polyurethane adhesive of the present invention not only performs well in traditional adhesive strength, but also achieves comprehensive improvements in thermal conductivity, mechanical strength, weather resistance and processing performance. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] The present application provides a high-adhesive polyol polyurethane adhesive, comprising component A and component B;

[0024] The component A comprises, by weight: 20 to 30 parts of polyol, 30 to 45 parts of boron nitride, 2 to 3 parts of auxiliary agent and 5 to 8 parts of catalyst;

[0025] The component B comprises, by weight, 10 to 35 parts of polyurethane, 25 to 50 parts of nano silicon dioxide and 1 to 5 parts of auxiliary agent.

[0026] In the present application, the polyol is selected from polyester polyol and / or polycarbonate polyol.

[0027] Among them, polyester polyols are condensation products of dibasic acids such as adipic acid, 1,4-succinic acid, and terephthalic acid with diols such as ethylene glycol, propylene glycol, and 1,4-butanediol; polycarbonate polyols are obtained by the reaction of aliphatic diols and carbonates, or by the polymerization of polyether segments and carbonate segments.

[0028] Furthermore, the polyester polyol is selected from at least one of polyethylene adipate, polyethylene terephthalate, and phthalic anhydride polyester polyol. The aliphatic diol is selected from 1,6-hexanediol or neopentyl glycol.

[0029] In the present application, the particle size of the boron nitride particles does not exceed 2 μm, and the particle size of the nano-silicon dioxide is 10 to 30 nm.

[0030] For boron nitride, its small particle size ensures uniform distribution in the adhesive system. This not only improves the thermal conductivity of the adhesive, helps to quickly disperse heat, and prevents bonding failure due to local overheating, but also enhances mechanical strength. The smaller particle size allows boron nitride to better fill the tiny gaps in the matrix material, thereby improving the density and stability of the overall structure, which is especially important for applications that require good thermal conductivity.

[0031] Secondly, the introduction of nano-silica greatly optimizes the mechanical properties and aging resistance of the adhesive. Its extremely small particle size (10-30nm) can form a stable network structure in the adhesive, which can not only significantly increase the mechanical strength and hardness of the adhesive, but also improve its tear resistance and wear resistance. In addition, this nano-scale filler can effectively prevent damage to the adhesive caused by ultraviolet rays and other environmental factors, extend its service life, and improve weather resistance. At the same time, nano-silica also has a good thickening effect, which helps to adjust the working viscosity of the adhesive, making it easier to operate and apply during the construction process.

[0032] In the present application, in order to further achieve better thermal conductivity, the filler may be further surface treated or shaped, for example, boron nitride or nano-silicon dioxide modified by a silane coupling agent.

[0033] The silane coupling agent is selected from one or a combination of two or more of γ-aminopropyltriethoxysilane, 3-glycidyloxypropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane or 1,3,5-tris(trimethoxysilylpropyl)isocyanurate.

[0034] In the technical solution of the present application, preferably, the filler selected for the two-component is a compound of at least two materials with different particle sizes or shapes. And in the present application, the thermal conductivity of the first filler is greater than the thermal conductivity of the second filler.

[0035] This application compounds boron nitride particles with a particle size range of no more than 2μm with nano-silicon dioxide with a particle size range of 10 to 30nm, which can significantly improve the performance of the material, especially showing unique advantages in thermal management. Boron nitride can effectively enhance the thermal conductivity of composite materials due to its excellent thermal conductivity, especially the high thermal conductivity along the layer direction, which helps to quickly disperse heat, reduce the formation of hot spots, and improve the stability and life of equipment. It is particularly suitable for application scenarios that require efficient heat dissipation, such as electronic packaging, thermal interface materials, etc. On the other hand, although nano-silicon dioxide has a relatively low thermal conductivity, it can provide excellent mechanical strength and wear resistance, and excels in improving the insulation, heat resistance and chemical stability of the material. In addition, the small size effect of nano-silicon dioxide can also increase the surface area of ​​the matrix material, improve dispersibility and processing performance, and help improve the overall quality and reliability of the final product.

[0036] Meanwhile, in the present application, there is good compatibility between polyurethane and composite filler, and polyurethane structure contains a large amount of polar groups, and such groups help to form good interaction with filler of specific type. Although boron nitride is essentially an inorganic material, after its surface is modified, its compatibility with polyurethane matrix is ​​enhanced. Similarly, nano silicon dioxide is also easy to improve the interfacial bonding force with polyurethane by surface modification due to its larger specific surface area and surface activity. This improved interfacial interaction can effectively prevent the agglomeration of filler, and promote the uniform dispersion of filler in matrix, thereby improving the overall performance of composite material.

[0037] In addition, the co-existence of boron nitride and nano-silica in the polyurethane matrix can produce a significant synergistic effect. Boron nitride is added mainly to improve thermal conductivity and mechanical strength, while nano-silica focuses on enhancing hardness, wear resistance and tear resistance, and helps to adjust the rheological properties of the adhesive. The combination of the two can not only further optimize the physical and mechanical properties of polyurethane without affecting its original excellent performance, but also complement each other. For example, the thermal conductivity path provided by boron nitride can reduce aging problems caused by local overheating, while the mechanical properties enhanced by nano-silica can protect these thermal conductivity paths from external damage. In addition, these two fillers can also work together to improve the weather resistance and environmental stability of the composite material, so that the final product remains stable and reliable in the face of various extreme conditions.

[0038] Furthermore, the catalyst is selected from one or more of organic tin catalysts and / or organic amine catalysts.

[0039] The catalyst is selected from one or more combinations of dibutyltin dilaurate, stannous chloride, triethylamine, and N,N-dimethylbenzylamine.

[0040] The auxiliary agents include antioxidants, flame retardants, color pastes, etc. Those skilled in the art can add them to improve the performance of the adhesive according to actual needs.

[0041] The antioxidant is selected from at least one of 2,6-di-tert-butyl-p-cresol and tocopherol;

[0042] The flame retardant is an inorganic flame retardant, which may include, but is not limited to, aluminum hydroxide, magnesium hydroxide, and red phosphorus.

[0043] The color paste is selected from at least one of inorganic color paste, organic color paste and water-based color paste, and examples thereof include, but are not limited to, iron oxide, phthalocyanine blue, water-based paint and the like.

[0044] On the other hand, the present application provides a method for preparing a two-component thermally conductive adhesive, comprising the following steps:

[0045] S1. Mix the polyol, boron nitride, additives and catalyst according to the mass fractions, heat and stir to obtain component A;

[0046] S2. Mix the polyurethane, nano-silicon dioxide and additives according to the weight ratio to obtain component B;

[0047] S3, mixing component A of step S1 with component B of step S2 to obtain a highly adhesive polyol polyurethane adhesive.

[0048] In the present application, in step S2, the preparation of the polyurethane comprises: mixing diphenylmethane isocyanate and polyol in a mass ratio of (1.1 to 1.3):1 to prepare the polyurethane.

[0049] The above preparation method not only ensures that the polyurethane has an ideal molecular weight and cross-linking density, thereby optimizing the mechanical properties and bonding strength of the final product, but also enables the conductive adhesive to have excellent thermal conductivity and heat resistance. Boron nitride and nano-silicon dioxide, as functional fillers, respectively improve the thermal conductivity and mechanical stability of the material. In addition, this ratio and preparation process also ensure that the two components can achieve optimal reactivity and compatibility when mixed, promote uniform dispersion and efficient curing, and reduce quality problems caused by local unevenness.

[0050] The following are specific examples of the present invention. If no specific conditions are specified in the examples, the experiments were carried out according to conventional conditions or conditions recommended by the manufacturer. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0051] Example 1

[0052] The high-adhesive polyol polyurethane adhesive of this embodiment is prepared by the following steps:

[0053] S1, 25 parts by weight of polyethylene adipate, 6 parts by weight of dibutyltin dilaurate, 40 parts by weight of boron nitride, and 2.5 parts by weight of 2,6-di-tert-butyl-p-cresol are mixed, the mixture is heated to 80° C. and stirred to obtain component A, which is then sealed and stored;

[0054] S2, 20 parts by weight of polyurethane (diphenylmethane isocyanate and polyol prepared in a mass ratio of 1.2:1), 35 parts by weight of nano-silicon dioxide, and 3 parts by weight of antioxidant 1010 were mixed, the mixture was heated to 60° C. and stirred to obtain component B, which was sealed and stored;

[0055] S3. Component A obtained in step S1 and component B obtained in step S2 are heated to 80° C. and then mixed in a ratio of 1:1 to obtain a high-adhesive polyol polyurethane adhesive.

[0056] Example 2

[0057] The high-adhesive polyol polyurethane adhesive of this embodiment is prepared by the following steps:

[0058] S1, 25 parts by weight of polyethylene adipate, 6 parts by weight of triethylamine, 40 parts by weight of boron nitride modified with γ-aminopropyltriethoxysilane, and 2.5 parts by weight of 2,6-di-tert-butyl-p-cresol are mixed, the mixture is heated to 80° C. and stirred to obtain component A, which is then sealed and stored;

[0059] S2, 20 parts by weight of polyurethane (prepared from diphenylmethane isocyanate and polyol in a mass ratio of 1.1:1), 35 parts by weight of nano-silica modified with γ-aminopropyltriethoxysilane, and 3 parts by weight of antioxidant 1010 were mixed, the mixture was heated to 60° C. and stirred to obtain component B, which was then sealed and stored;

[0060] S3. Component A obtained in step S1 and component B obtained in step S2 are heated to 80° C. and then mixed in a ratio of 1:1 to obtain a high-adhesive polyol polyurethane adhesive.

[0061] Example 3

[0062] The high-adhesive polyol polyurethane adhesive of this embodiment is prepared by the following steps:

[0063] S1, 25 parts by weight of polyethylene adipate, 6 parts by weight of triethylamine, 40 parts by weight of boron nitride modified with 3-glycidyloxypropyltriethoxysilane, and 2.5 parts by weight of 2,6-di-tert-butyl-p-cresol were mixed, the mixture was heated to 80° C. and stirred to obtain component A, which was then sealed and stored;

[0064] S2, 20 parts by weight of polyurethane (prepared from diphenylmethane isocyanate and polyol in a mass ratio of 1.3:1), 35 parts by weight of nano-silica modified with 3-glycidyloxypropyltriethoxysilane, and 3 parts by weight of antioxidant 1010 were mixed, the mixture was heated to 60° C. and stirred to obtain component B, which was then sealed and stored;

[0065] S3. Component A obtained in step S1 and component B obtained in step S2 are heated to 80° C. and then mixed in a ratio of 1:1 to obtain a high-adhesive polyol polyurethane adhesive.

[0066] Comparative Example 1

[0067] The difference from Example 1 is that boron nitride and nano silicon dioxide are not contained.

[0068] Comparative Example 2

[0069] The difference from Example 2 is that boron nitride with a particle size of 15 to 40 μm and silicon dioxide with a particle size of 0.1 to 20 μm are selected.

[0070] Comparative Example 3

[0071] The difference from Example 3 is that nano silicon dioxide is added to component A, and boron nitride is added to component B.

[0072] The above-mentioned Examples 1 to 3 and Comparative Examples 1 to 3 were subjected to the following performance tests, including:

[0073] (1) Thermal conductivity: The thermal conductivity of each formulation was measured using the hot wire method or the laser flash method.

[0074] (2) Mechanical strength: The tensile strength and elongation at break were tested using a tensile testing machine.

[0075] (3) Dispersion uniformity: Use a microscope to observe the distribution of fillers in the matrix and evaluate its dispersion effect.

[0076] (4) Adhesion: Adhesion test was performed on metal plates according to standard methods (such as ASTM D1002).

[0077] (5) Weather resistance: After the samples are exposed to ultraviolet light for a certain period of time, their color change, gloss loss, and changes in mechanical properties are evaluated.

[0078] The above performance test results are recorded in Table 1 below.

[0079] Table 1 Performance test results

[0080]

[0081]

[0082] It can be seen from Table 1 that after using fillers modified by silane coupling agents in Examples 2 and 3, a tighter and more uniform bond is formed with the polyurethane matrix, thereby effectively improving the overall performance of the composite material. Specifically, the use of silane coupling agents such as γ-aminopropyltriethoxysilane and 3-glycidyloxypropyltriethoxysilane not only improves the dispersibility of boron nitride and nano-silicon dioxide, reduces the agglomeration phenomenon between particles, but also enhances the interfacial interaction between the filler and the polymer matrix, making the stress distribution more uniform and improving the mechanical strength and toughness of the material. In contrast, although Example 1 also shows good performance, its performance improvement is limited due to the lack of surface modification of the filler; and Comparative Example 1 has the worst overall performance due to the lack of filler reinforcement. It can be predicted that the selection and use of fillers play a key role in improving the performance of adhesives. The presence of large-particle fillers in Comparative Example 2 leads to discontinuous and unevenly dispersed heat conduction paths, which seriously affects the thermal conductivity and mechanical strength of the adhesive; while the performance of Comparative Example 3 decreases. The reason for this may be that boron nitride usually needs to be evenly dispersed to form a continuous heat conduction path. If the filler cannot be well dispersed in the matrix, local hot spots will be formed, which will hinder the effective conduction of heat. Especially in high-viscosity polyurethane systems, the presence of large particles or agglomerates will seriously affect the continuity of the heat conduction path. When it is added to component B, which is mainly composed of polyurethane, it may not be fully combined with other ingredients (such as polyols) as in component A, resulting in discontinuous heat conduction paths and affecting the overall thermal conductivity. Similarly, nano-silicon dioxide works together with polyurethane and other ingredients in the original formula to help build a stable heat conduction network. In Comparative Example 3, placing it in component A may limit its optimal performance, because the chemical environment and physical conditions in component A are different from those in component B, which is not conducive to nano-silicon dioxide to exert its optimal dispersion and thermal conductivity enhancement effect.

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-adhesive polyol polyurethane adhesive, characterized in that: Comprising component A and component B; The component A comprises, by weight: 20 to 30 parts of polyol, 30 to 45 parts of boron nitride, 2 to 3 parts of auxiliary agent and 5 to 8 parts of catalyst; The component B comprises, by weight, 10 to 35 parts of polyurethane, 25 to 50 parts of nano silicon dioxide and 1 to 5 parts of auxiliary agent.

2. The high-adhesive polyol polyurethane adhesive according to claim 1, characterized in that: The polyol is selected from polyester polyol and / or polycarbonate polyol.

3. The high-adhesive polyol polyurethane adhesive according to claim 1, characterized in that: The particle size of the boron nitride particles does not exceed 2 μm.

4. The high-adhesive polyol polyurethane adhesive according to claim 1, characterized in that: The catalyst is selected from one or more of an organic tin catalyst and / or an organic amine catalyst.

5. The high-adhesive polyol polyurethane adhesive according to claim 1, characterized in that: The auxiliary agent is selected from one or more of antioxidants, flame retardants or color pastes.

6. The high-adhesive polyol polyurethane adhesive according to claim 1, characterized in that: The particle size of the nano silicon dioxide is 10 to 30 nm.

7. A method for preparing the highly adhesive polyol polyurethane adhesive according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Mix the polyol, boron nitride, additives and catalyst according to the mass fractions, heat and stir to obtain component A; S2. Mix the polyurethane, nano-silicon dioxide and additives according to the weight ratio to obtain component B; S3, mixing component A of step S1 with component B of step S2 to obtain a highly adhesive polyol polyurethane adhesive.

8. The method for preparing the high-adhesive polyol polyurethane adhesive according to claim 7, characterized in that: In step S2, the preparation of the polyurethane includes: mixing diphenylmethane isocyanate and polyol in a mass ratio of (1.1-1.3):1 to prepare the polyurethane.

9. Use of the high-adhesive polyol polyurethane adhesive according to any one of claims 1 to 6 in batteries.

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