A flame retardant polyurethane adhesive and its preparation method and application

Abstract

The invention discloses a flame retardant polyurethane adhesive, comprising the following components in parts by weight: 40-60 parts of polyether polyol, 10-20 parts of hydroxyl-terminated polydimethylsiloxane, 40-70 parts of isocyanate, 2-9 parts of 4-hydroxybutyl acrylate modified polyurethane, 5-25 parts of flame retardant, 0.5-7 parts of coupling agent, 1-5 parts of thixotropic agent and 0.1-1 parts of catalyst, wherein the flame retardant is RAYNOL FR-300 / zirconium phosphate / MMT. The flame retardant polyurethane adhesive of the invention has excellent bonding performance and stable and good flame retardant performance, and can be used for sealing and bonding of electrical components.

Description

Technical Field

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

[0002] With the rapid development of the electronics manufacturing industry, electronic adhesives are becoming increasingly important in the manufacturing process. Electronic adhesives are widely used in mobile devices, computers, communications equipment, home entertainment, automobiles, aerospace and other fields, among which the demand for consumer electronic products such as mobile phones and tablets is the most vigorous.

[0003] Polyurethane electronic adhesive is an adhesive used in the electronics industry. Because its molecular chain contains urethane and isocyanate groups, it has high reactivity and excellent adhesive properties. It can be cured at room temperature and is resistant after curing. It is suitable for bonding, sealing and coating processes of electronic components, circuit boards, displays, sensors, etc. Polyurethane adhesives also have some disadvantages, such as poor heat resistance, flammability, large flames, fast burning speed, thick smoke and toxic gases when burning. Therefore, it is necessary to improve the flame retardant properties of polyurethane electronic adhesives.

[0004] At present, the flame retardants in polyurethane are mainly additive flame retardants. The use of additive flame retardants has disadvantages such as easy migration and inability to maintain flame retardant effects for a long time, which often leads to a decrease in the mechanical properties and adhesion properties of the product. Therefore, polyurethane foams made with additive flame retardants can only be used in fields where flame retardancy requirements are not very high.

[0005] Therefore, it is necessary to further develop polyurethane adhesives with more durable and stable flame retardant effects. Summary of the invention

[0006] In view of the above problems, the purpose of the present invention is to provide a flame retardant polyurethane adhesive and its preparation method and application. The flame retardant polyurethane adhesive is obtained by reacting a reactive flame retardant with various components of polyurethane, and can obtain excellent bonding performance and stable and good flame retardant performance.

[0007] To this end, the present invention adopts the following technical solutions:

[0008] The invention provides a flame retardant polyurethane adhesive, comprising the following components in parts by weight: 40-60 parts of polyether polyol, 10-20 parts of terminal hydroxyl polydimethylsiloxane, 40-70 parts of isocyanate, 2-9 parts of 4-hydroxybutyl acrylate modified polyurethane, 5-25 parts of flame retardant, 0.5-7 parts of coupling agent, 1-5 parts of thixotropic agent and 0.1-1 parts of catalyst, wherein the flame retardant is RAYNOLFR-300 / zirconium phosphate / MMT.

[0009] Preferably, the polyether polyol is an epoxy-containing polyether polyol.

[0010] Preferably, the epoxy-containing polyether polyol is selected from at least one of polypropylene oxide ether polyol, polyethylene oxide ether polyol and polypropylene oxide-ethylene oxide ether copolymer polyol.

[0011] Preferably, the preparation method of the 4-hydroxybutyl acrylate modified polyurethane comprises the following steps: reacting polyester polyol, isophorone diisocyanate and 4-hydroxybutyl acrylate at 65-85° C. for 2-3 hours under the action of dibutyl dilaurate catalyst, adding a polymerization inhibitor after cooling to 50° C., and preparing the 4-hydroxybutyl acrylate modified polyurethane after stirring.

[0012] Furthermore, the preparation method of the flame retardant RAYNOL FR-300 / zirconium phosphate / MMT comprises the following steps:

[0013] S1, dissolving zirconium phosphate and montmorillonite MMT in water in a weight ratio of (1-2):(1-3), stirring for reaction for 3-8 hours, centrifuging, collecting solids, drying and grinding the solids to obtain a zirconium phosphate / MMT mixture;

[0014] S2, stirring the flame retardant RAYNOL FR-300 and the zirconium phosphate / MMT mixture at 75-90° C. for 2-5 hours, and cooling to room temperature to obtain the flame retardant RAYNOL FR-300 / zirconium phosphate / MMT.

[0015] Preferably, the weight ratio of the RAYNOL FR-300 to the zirconium phosphate / MMT mixture is 100:(1-15).

[0016] Preferably, the isocyanate is one or more of 4,4′-diphenylmethane diisocyanate, 4,4′-dicyclohexylmethane diisocyanate and isophorone diisocyanate.

[0017] Preferably, the coupling agent is a silane coupling agent, selected from one or more of γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane and γ-(2,3-epoxypropyl)propyltrimethoxysilane.

[0018] Preferably, the thixotropic agent is fumed silica.

[0019] Preferably, the catalyst is one or more of dibutyltin dilaurate, stannous octoate, diethylenetriamine, and triethylamine.

[0020] The present invention also provides a method for preparing a flame retardant polyurethane adhesive, comprising the following steps:

[0021] (1) adding polyether polyol, hydroxyl-terminated polydimethylsiloxane, isocyanate and catalyst into a reaction kettle, reacting at 70-90° C. for 1-3 h, adding flame retardant, and continuing stirring for 0.5-1 h to obtain a prepolymer;

[0022] (2) After the prepolymer is heated to room temperature, 4-hydroxybutyl acrylate modified polyurethane, a coupling agent and a thixotropic agent are added, and the mixture is stirred and mixed to obtain a flame retardant polyurethane adhesive.

[0023] The present invention further provides a use of a flame retardant polyurethane adhesive for sealing and bonding electrical components.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The polyurethane adhesive provided by the present invention is prepared by reacting epoxy-containing polyether polyol, terminal hydroxyl polydimethylsiloxane and isocyanate to obtain a prepolymer, which is reacted with reactive flame retardant RAYNOL FR-300 and zirconium phosphate / MMT, and then combined with 4-hydroxybutyl acrylate modified polyurethane to obtain excellent bonding performance and flame retardant performance.

[0026] The reactive flame retardant RAYNOL FR-300 and zirconium phosphate / MMT provided by the present invention overcome the disadvantages of uneven dispersion of inorganic flame retardants and poor heat resistance of organic flame retardants, can be combined with polyurethane molecular chains through reaction, are evenly dispersed, and have good stability. DETAILED DESCRIPTION

[0027] The specific implementation methods of the technical solution of this specification are further described below through specific examples. These examples are for the purpose of describing the technical solution in detail, rather than for limiting the technical solution. Based on the examples in this specification, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this specification.

[0028] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art, and the reagents and materials used in the following examples are commercially available:

[0029] Polypropylene oxide-ethylene oxide ether polyol, product brand: Wanol F3128, purchased from Wanhua Chemical Group Co., Ltd.;

[0030] Hydroxyl-terminated polydimethylsiloxane, CAS No.: 70131-67-8, purchased from Qiyuan (Guangdong) Pharmaceutical Chemical Co., Ltd.;

[0031] Isophorone diisocyanate (IPDI) was purchased from Qingdao Xinyutian Chemical Co., Ltd., China;

[0032] Flame retardant RAYNOL FR-300 was purchased from Qingdao Ruinuo Chemical Co., Ltd.;

[0033] Polyester polyols were purchased from Jiangsu Bosite Chemical Technology Co., Ltd.;

[0034] 4-Hydroxybutyl acrylate, CAS No.: 2478-10-6, was purchased from Wuhan Kemik Biopharmaceutical Technology Co., Ltd.;

[0035] Polyurethane inhibitor NCAT-YC01 was purchased from Guangzhou Yourun Synthetic Materials Co., Ltd.;

[0036] γ-(2,3-Epoxypropyl)propyltrimethoxysilane was purchased from Tianmen Hengchang Chemical Co., Ltd.;

[0037] Zirconium phosphate, CAS No.: 13772-29-7α, was purchased from Wuhan Kemik Biopharmaceutical Technology Co., Ltd.;

[0038] Ultrafine montmorillonite MMT was purchased from Guangzhou Xijia New Materials Co., Ltd.;

[0039] Fumed silica A200 was purchased from Wuhan Jinqu New Materials Co., Ltd.;

[0040] Dibutyltin dilaurate was purchased from Shandong Zhijia Chemical Technology Co., Ltd.

[0041] Example 1

[0042] A flame retardant polyurethane adhesive comprises the following components in parts by weight: 50 parts of polypropylene oxide-ethylene oxide ether polyol, 15 parts of terminal hydroxyl polydimethylsiloxane, 40 parts of isophorone diisocyanate, 4 parts of 4-hydroxybutyl acrylate modified polyurethane, 15 parts of flame retardant, 1 part of γ-(2,3-epoxypropyl)propyltrimethoxysilane, 1 part of fumed silica and 0.3 part of dibutyltin dilaurate, wherein the flame retardant is RAYNOL FR-300 / zirconium phosphate / MMT.

[0043] The preparation method of 4-hydroxybutyl acrylate modified polyurethane comprises the following steps: reacting polyester polyol, isophorone diisocyanate and 4-hydroxybutyl acrylate under the action of dibutyl dilaurate catalyst at 80° C. for 2.5 hours, adding polymerization inhibitor NCAT-YC01 after cooling to 50° C., and preparing 4-hydroxybutyl acrylate modified polyurethane after stirring.

[0044] The preparation method of the flame retardant RAYNOL FR-300 / zirconium phosphate / MMT comprises the following steps:

[0045] S1, dissolving zirconium phosphate and montmorillonite MMT in water at a weight ratio of 1:2, stirring and reacting for 5 hours, centrifuging, collecting solids, drying and grinding the solids to obtain a zirconium phosphate / MMT mixture;

[0046] S2, flame retardant RAYNOL FR-300 and the above zirconium phosphate / MMT mixture, the addition amount of the zirconium phosphate / MMT mixture is 5%, stirring and reacting at 85° C. for 5 hours, cooling to room temperature, to obtain flame retardant RAYNOL FR-300 / zirconium phosphate / MMT.

[0047] A method for preparing a flame retardant polyurethane adhesive comprises the following steps:

[0048] (1) adding polypropylene oxide-ethylene oxide ether polyol, terminal hydroxyl polydimethylsiloxane, isophorone diisocyanate and dibutyltin dilaurate into a reaction kettle, reacting at 75° C. for 1.5 h, adding flame retardant RAYNOL FR-300 / zirconium phosphate / MMT, and continuing stirring for 1 h to obtain a prepolymer;

[0049] (2) After the prepolymer is cooled to room temperature, 4-hydroxybutyl acrylate modified polyurethane, γ-(2,3-epoxypropyl)propyltrimethoxysilane and fumed silica are added, and the mixture is stirred and mixed to obtain a flame retardant polyurethane adhesive.

[0050] Example 2

[0051] A flame retardant polyurethane adhesive comprises the following components in parts by weight: 50 parts of polypropylene oxide-ethylene oxide ether polyol, 10 parts of terminal hydroxyl polydimethylsiloxane, 45 parts of isophorone diisocyanate, 3 parts of 4-hydroxybutyl acrylate modified polyurethane, 10 parts of flame retardant, 1 part of γ-(2,3-epoxypropyl)propyltrimethoxysilane, 1 part of fumed silica and 0.7 part of dibutyltin dilaurate, wherein the flame retardant is RAYNOL FR-300 / zirconium phosphate / MMT.

[0052] The preparation method of 4-hydroxybutyl acrylate modified polyurethane comprises the following steps: reacting polyester polyol, isophorone diisocyanate and 4-hydroxybutyl acrylate under the action of dibutyl dilaurate catalyst at 80° C. for 2.5 hours, adding polymerization inhibitor NCAT-YC01 after cooling to 50° C., and preparing 4-hydroxybutyl acrylate modified polyurethane after stirring.

[0053] The preparation method of the flame retardant RAYNOL FR-300 / zirconium phosphate / MMT comprises the following steps:

[0054] S1, dissolving zirconium phosphate and montmorillonite MMT in water at a weight ratio of 1:3, stirring and reacting for 5 hours, centrifuging, collecting solids, drying and grinding the solids to obtain a zirconium phosphate / MMT mixture;

[0055] S2, flame retardant RAYNOL FR-300 and the above zirconium phosphate / MMT mixture are added in an amount of 3%, the zirconium phosphate / MMT mixture is added in an amount of 3%, stirred and reacted at 85° C. for 5 h, and then cooled to room temperature to obtain flame retardant RAYNOL FR-300 / zirconium phosphate / MMT.

[0056] A method for preparing a flame retardant polyurethane adhesive comprises the following steps:

[0057] (1) adding polypropylene oxide-ethylene oxide ether polyol, terminal hydroxyl polydimethylsiloxane, isophorone diisocyanate and dibutyltin dilaurate into a reaction kettle, reacting at 75° C. for 1.5 h, adding flame retardant RAYNOL FR-300 / zirconium phosphate / MMT, and continuing stirring for 1 h to obtain a prepolymer;

[0058] (2) After the prepolymer is cooled to room temperature, 4-hydroxybutyl acrylate modified polyurethane, γ-(2,3-epoxypropyl)propyltrimethoxysilane and fumed silica are added, and the mixture is stirred and mixed to obtain a flame retardant polyurethane adhesive.

[0059] Example 3

[0060] A flame retardant polyurethane adhesive comprises the following components in parts by weight: 60 parts of polypropylene oxide-ethylene oxide ether polyol, 20 parts of terminal hydroxyl polydimethylsiloxane, 62 parts of isophorone diisocyanate, 9 parts of 4-hydroxybutyl acrylate modified polyurethane, 25 parts of flame retardant, 1 part of γ-(2,3-epoxypropyl)propyltrimethoxysilane, 1.2 parts of fumed silica and 0.7 parts of dibutyltin dilaurate, wherein the flame retardant is RAYNOL FR-300 / zirconium phosphate / MMT.

[0061] The preparation method of 4-hydroxybutyl acrylate modified polyurethane comprises the following steps: reacting polyester polyol, isophorone diisocyanate and 4-hydroxybutyl acrylate under the action of dibutyl dilaurate catalyst at 80° C. for 2.5 hours, adding polymerization inhibitor NCAT-YC01 after cooling to 50° C., and preparing 4-hydroxybutyl acrylate modified polyurethane after stirring.

[0062] The preparation method of the flame retardant RAYNOL FR-300 / zirconium phosphate / MMT comprises the following steps:

[0063] S1, dissolving zirconium phosphate and montmorillonite MMT in water at a weight ratio of 1:1, stirring for 5 hours, centrifuging, collecting solids, drying and grinding the solids to obtain a zirconium phosphate / MMT mixture;

[0064] S2, flame retardant RAYNOL FR-300 and the above zirconium phosphate / MMT mixture, the addition amount of the zirconium phosphate / MMT mixture is 5%, stirring and reacting at 85° C. for 5 hours, cooling to room temperature, to obtain flame retardant RAYNOL FR-300 / zirconium phosphate / MMT.

[0065] A method for preparing a flame retardant polyurethane adhesive comprises the following steps:

[0066] (1) adding polypropylene oxide-ethylene oxide ether polyol, terminal hydroxyl polydimethylsiloxane, isophorone diisocyanate and dibutyltin dilaurate into a reaction kettle, reacting at 75° C. for 1.5 h, adding flame retardant RAYNOL FR-300 / zirconium phosphate / MMT, and continuing stirring for 1 h to obtain a prepolymer;

[0067] (2) After the prepolymer is cooled to room temperature, 4-hydroxybutyl acrylate modified polyurethane, γ-(2,3-epoxypropyl)propyltrimethoxysilane and fumed silica are added, and the mixture is stirred and mixed to obtain a flame retardant polyurethane adhesive.

[0068] Comparative Example 1

[0069] Compared with Example 1, the difference is that the flame retardant RAYNOL FR-300 / zirconium phosphate / MMT is not added, and the other parts are the same.

[0070] The preparation method is the same as Example 1.

[0071] Comparative Example 2

[0072] Compared with Example 1, the difference is that the flame retardant is replaced by RAYNOL FR-300 in the same weight proportion, and the other parts are the same.

[0073] The preparation method is the same as Example 1.

[0074] Comparative Example 3

[0075] Compared with Example 1, the difference is that the flame retardant is replaced by MMT in the same weight proportion, and the other parts are the same.

[0076] The preparation method is the same as Example 1.

[0077] Comparative Example 4

[0078] Compared with Example 1, the difference is that the flame retardant is replaced by RAYNOL FR-300, zirconium phosphate and MMT in the same weight proportions, and the other parts are the same.

[0079] The preparation method is the same as Example 1.

[0080] Comparative Example 5

[0081] Compared with Example 1, the difference is that the flame retardant is replaced by magnesium hydroxide in the same weight portion, and the other parts are the same.

[0082] The preparation method is the same as Example 1.

[0083] Comparative Example 6

[0084] Compared with Example 1, the difference is that no 4-hydroxybutyl acrylate modified polyurethane is added, and the other parts are the same.

[0085] The preparation method is the same as Example 1.

[0086] Comparative Example 7

[0087] Compared with Example 1, the difference is that the weight parts of some components are different: 10 parts of polyether polyol, 50 parts of terminal hydroxyl polydimethylsiloxane, 1 part of 4-hydroxybutyl acrylate modified polyurethane, and the others are the same.

[0088] The preparation method is the same as Example 1.

[0089] Performance Test:

[0090] (1) Room temperature tensile shear strength test: The test method refers to standard GB / T 7124-2008.

[0091] (2) Flame retardant performance test: The cured polyurethane adhesive was cut into test strips with a length, width and height of 125 mm × 12.5 mm × 2 mm. The test method was based on the standard GB / T 2408-2008.

[0092] (3) Limiting oxygen index (LOI): The cured polyurethane adhesive was cut into test strips of 140 mm × 6 mm × 3 mm. The test method was based on the standard GB / T 2406.2-2009.

[0093] The test results are shown in Table 1.

[0094] Table 1 Performance test results

[0095]

[0096]

[0097] It can be seen from Table 1 that the flame retardant polyurethane adhesives provided by Examples 1-3 of the present invention have good tensile shear strength and good flame retardant properties.

[0098] Compared with Example 1, in Comparative Example 1, no flame retardant RAYNOL FR-300 / zirconium phosphate / MMT was added, and the oxygen index and flame retardancy level were significantly reduced, indicating that the flame retardant RAYNOL FR-300 / zirconium phosphate / MMT provided by the present invention can significantly enhance the flame retardancy of the polyurethane adhesive.

[0099] Compared with Example 1, in Comparative Example 2, the flame retardant is replaced with RAYNOL FR-300 of the same weight, and the oxygen index and flame retardancy level are significantly reduced, indicating that the flame retardant RAYNOL FR-300 / zirconium phosphate / MMT provided by the present invention has a better effect of enhancing the flame retardant properties of the polyurethane adhesive than RAYNOL FR-300.

[0100] Compared with Example 1, in Comparative Example 3, the flame retardant is replaced with MMT of the same weight, and the oxygen index and flame retardancy level are significantly reduced, indicating that the flame retardant RAYNOL FR-300 / zirconium phosphate / MMT provided by the present invention has a better effect of enhancing the flame retardant properties of the polyurethane adhesive than using MMT alone, and the inorganic MMT is easily unevenly dispersed, affecting the flame retardant effect.

[0101] Compared with Example 1, in Comparative Example 4, the flame retardant is replaced with RAYNOL FR-300, zirconium phosphate, and MMT in the same weight proportions, and the oxygen index and flame retardancy level are reduced, indicating that the flame retardant RAYNOL FR-300 / zirconium phosphate / MMT provided by the present invention has a better effect of enhancing the flame retardant properties of the polyurethane adhesive than conventionally mixing the three components.

[0102] Compared with Example 1, in Comparative Example 5, the flame retardant is replaced with magnesium hydroxide in the same weight proportion, and the oxygen index and flame retardancy level are both reduced, indicating that the flame retardant RAYNOL FR-300 / zirconium phosphate / MMT provided by the present invention has a better effect of increasing the flame retardancy of the polyurethane adhesive than magnesium hydroxide.

[0103] Compared with Example 1, in Comparative Example 6, no 4-hydroxybutyl acrylate modified polyurethane was added, and the tensile shear strength was significantly reduced, indicating that the 4-hydroxybutyl acrylate modified polyurethane formula provided by the present invention has better bonding performance.

[0104] Compared with Example 1, the polyether polyol, terminal hydroxyl polydimethylsiloxane, and 4-hydroxybutyl acrylate modified polyurethane in the adhesive provided in Comparative Example 7 are not within the formula ratio range of the present invention, the tensile shear strength is significantly reduced, and the flame retardant performance is also slightly reduced, indicating that the adhesive prepared with a suitable ratio can have better and more stable bonding ability and flame retardant performance.

[0105] In summary, the flame retardant polyurethane adhesive provided by the present invention has excellent adhesion and flame retardancy.

[0106] Although the embodiments of the present description have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present description, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A flame retardant polyurethane adhesive, characterized in that: The invention comprises the following components in parts by weight: 40-60 parts of polyether polyol, 10-20 parts of terminal hydroxyl polydimethylsiloxane, 40-70 parts of isocyanate, 2-9 parts of 4-hydroxybutyl acrylate modified polyurethane, 5-25 parts of flame retardant, 0.5-7 parts of coupling agent, 1-5 parts of thixotropic agent and 0.1-1 parts of catalyst, wherein the flame retardant is RAYNOLFR-300 / zirconium phosphate / MMT; the preparation method of the 4-hydroxybutyl acrylate modified polyurethane comprises the following steps: reacting polyester polyol, isophorone diisocyanate and 4-hydroxybutyl acrylate at 65-85°C for 2-3h under the action of dibutyl dilaurate catalyst, cooling to 50°C, adding inhibitor, stirring and preparing 4-hydroxybutyl acrylate modified polyurethane; the flame retardant RAYNOL The preparation method of FR-300 / zirconium phosphate / MMT comprises the following steps: S1, dissolving zirconium phosphate and montmorillonite MMT in water in a weight ratio of (1-2):(1-3), stirring and reacting for 3-8 hours, centrifuging, collecting solids, drying and grinding the solids to obtain a zirconium phosphate / MMT mixture; S2, stirring and reacting the flame retardant RAYNOL FR-300 and the above zirconium phosphate / MMT mixture at a temperature of 75-90° C. for 2-5 hours, cooling to room temperature, and obtaining the flame retardant RAYNOL FR-300 / zirconium phosphate / MMT; the weight ratio of the RAYNOL FR-300 to the zirconium phosphate / MMT mixture is 100:(1-15).

2. The flame retardant polyurethane adhesive according to claim 1, characterized in that: The isocyanate is one or more of 4,4'-diphenylmethane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and isophorone diisocyanate; and / or the coupling agent is a silane coupling agent, selected from one or more of γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, and γ-(2,3-epoxypropyl)propyltrimethoxysilane.

3. The flame retardant polyurethane adhesive according to claim 1, characterized in that: The thixotropic agent is fumed silica; and / or the catalyst is one or more of dibutyltin dilaurate, stannous octoate, diethylenetriamine, and triethylamine.

4. The method for preparing the flame retardant polyurethane adhesive according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: (1) adding polyether polyol, terminal hydroxyl polydimethylsiloxane, isocyanate and catalyst into a reaction kettle, reacting at 70-90° C. for 1-3 hours, adding a flame retardant, and continuing stirring for 0.5-1 hour to obtain a prepolymer; (2) after cooling the prepolymer to room temperature, adding 4-hydroxybutyl acrylate modified polyurethane, a coupling agent and a thixotropic agent, stirring and mixing evenly, and obtaining a flame retardant polyurethane adhesive.

5. The use of the flame retardant polyurethane adhesive according to any one of claims 1 to 3, characterized in that: Used for sealing and bonding of electrical components.

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