Double-spiro phosphate and organic silicon synergistic flame-retardant UV (ultraviolet) curing polyurethane and preparation method thereof

Abstract

The preparation method comprises the following steps: adding a hydroxyl derivative of bis-spiro pentaerythritol diphosphate and hydroxyl-terminated polysiloxane into a three-neck flask which is provided with a mechanical stirrer and a thermometer together, uniformly stirring, adding an organic silicon catalyst, stirring, adding an organic silicon catalyst, stirring, adding an organic silicon catalyst, stirring, adding an organic silicon catalyst, stirring, adding an organic silicon catalyst, stirring, adding an organic silicon catalyst, and stirring to obtain the UV-cured polyurethane with the synergistic flame retardance of the bis-spiro phosphate and the organic silicon, thereby obtaining the UV-cured polyurethane with the synergistic flame retardance. Dibutyltin dilaurate and diisocyanate are dropwise added for a reaction, then hydroxypropyl methacrylate is added, the reaction continues to be conducted, and a polyurethane prepolymer containing bis-spiro phosphate and organic silicon is obtained; and then adding an ultraviolet light initiator, and carrying out UV curing to obtain the UV-cured polyurethane. The pencil hardness of the UV curing material is 2B-9H, the initial thermal decomposition temperature is 246.0-298.2 DEG C, the LOI is 26.0-33.2%, the flame retardant grade is V-1-V-0 grade, and the UV curing material can be used as an electronic flame retardant sealant, a flame retardant three-proofing paint, a flame retardant industrial paint, a flame retardant tent cloth coating and the like.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to UV-curable polyurethane with synergistic flame retardancy of bispirocyclic phosphate and organosilicon and a preparation method thereof. Background Art

[0002] Organic polymer materials have the advantages of good chemical stability, high mechanical strength and easy molding, and have been widely used in people's lives. However, they have the disadvantage of being easy to burn, which can easily cause fires and endanger people's lives and property. Therefore, it is urgent to modify organic polymer materials to be flame retardant and expand their application fields.

[0003] Spiro-type flame retardants have good compatibility with polymer materials and can maintain their excellent flame retardancy under high temperature or harsh environment. They are widely used in flame retardant modification of organic polymer materials. In addition, spiro-type flame retardants have a unique chemical structure, which enables them to quickly form a stable carbon layer when heated, thereby effectively isolating oxygen and heat, slowing down the burning speed of organic polymer materials, and preventing the further spread of flames, thereby improving the flame retardant properties of the materials. Spiro-type flame retardants usually contain multiple elements such as phosphorus and nitrogen, and multiple elements can synergistically enhance the flame retardant effect. Compared with traditional flame retardants, spiro-type flame retardants also have low toxicity.

[0004] Ultraviolet (UV) curing is a new energy-saving and environmentally friendly technology with the advantages of fast curing and environmental friendliness. It has been widely used in important fields such as coatings, inks and electronic packaging. Summary of the invention

[0005] The purpose of the present invention is to provide a UV-curable polyurethane with synergistic flame retardancy of bispirocyclic phosphate and organosilicon and a preparation method thereof in view of the shortcoming that the existing polyurethane material is easy to burn.

[0006] The purpose of the present invention can be achieved through the following technical solutions: A method for preparing UV-curable polyurethane with synergistic flame retardancy of bispirocyclic phosphate and organosilicon, comprising the following steps: The hydroxyl derivative of dispirocyclic pentaerythritol diphosphate and hydroxyl-terminated polysiloxane are added together into a three-necked flask equipped with a mechanical stirrer and a thermometer, and after being stirred evenly, dibutyltin dilaurate and diisocyanate are added dropwise, and the mixture is reacted at 40-80° C. for 4-6 hours, and then hydroxypropyl methacrylate is added, and the mixture is reacted at 40-80° C. for 4-8 hours to obtain a polyurethane prepolymer containing dispirocyclic phosphate and silicone; Then, 1-10 wt% of the prepolymer mass of ultraviolet light initiator is added, and UV curing is performed to obtain the UV-cured polyurethane with synergistic flame retardancy of the bispirocyclic phosphate and silicone.

[0007] As a specific embodiment, the hydroxyl derivative of the dispirocyclic pentaerythritol diphosphate is a liquid tetrahydroxy SPDPC derivative, and its preparation steps are as follows: Step 1, pentaerythritol and phosphorus oxychloride are added to a three-necked flask in a molar ratio of 1:2, and the mixture is heated to 100°C with stirring for 12 hours. The tail gas is absorbed by a saturated NaOH solution. After the reaction is completed, the mixture is cooled to room temperature and filtered through a Buchner funnel to obtain a white solid, which is then washed with anhydrous dichloromethane and dried in a vacuum oven at 60°C to constant weight to obtain a white solid powder SPDPC. The specific reaction formula is as follows: ; Step 2, dissolve SPDPC in anhydrous acetonitrile of equal mass, and dropwise add 2 times molar amount of diethanolamine and 2 times molar amount of triethylamine in anhydrous acetonitrile solution, then react at 60°C for 2 h, then heat and reflux for 12 h, cool and filter, and remove acetonitrile from the filtrate under reduced pressure to obtain a liquid tetrahydroxy SPDPC derivative. The specific reaction formula is as follows: .

[0008] As a specific embodiment, the molecular structure of the hydroxyl-terminated polysiloxane is HOMe2SiO(Me2SiO) n SiMe2OH, wherein n is an integer from 10 to 500.

[0009] As a specific implementation method, in the process of preparing the bispirocyclic phosphate and silicone polyurethane prepolymer, the diisocyanate and the mixture of the hydroxyl derivative of the bispirocyclic pentaerythritol diphosphate and the hydroxyl-terminated polysiloxane are added according to the molar ratio of isocyanate group to hydroxyl group of 3:1 to 1.2:1; The molar ratio of the hydroxy derivative of dispirocyclopentaerythritol diphosphate to the hydroxyl-terminated polysiloxane is 0.05:1-1:1.

[0010] As a specific implementation manner, in the process of preparing the bispirocyclic phosphate and silicone polyurethane prepolymer, the addition amount of dibutyltin dilaurate is 0.4% of the total mass of the hydroxyl derivative of bispirocyclic pentaerythritol diphosphate and the hydroxyl-terminated polysiloxane.

[0011] As a specific implementation, the diisocyanate is one or more of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate isomer mixture, diphenylmethane diisocyanate, 1,6-hexamethylene diisocyanate, and isophorone diisocyanate.

[0012] The second object of the present invention is to provide a UV-curing polyurethane with synergistic flame retardancy of bis-spirocyclic phosphate and silicone prepared by the above-mentioned method for preparing UV-curing polyurethane with synergistic flame retardancy of bis-spirocyclic phosphate and silicone. The UV-curing polyurethane with synergistic flame retardancy of bis-spirocyclic phosphate and silicone has a pencil hardness of 2B~9H, an initial thermal decomposition temperature of 246.0~298.2°C, and a limiting oxygen index of 26.0~33.2%.

[0013] The third object of the present invention is to provide the application of the above-mentioned UV-cured polyurethane with synergistic flame retardancy of bispirocyclic phosphate and silicone in electronic flame retardant sealants, flame retardant three-proof paints for electronic components, flame retardant industrial paints, and flame retardant tent cloth coatings.

[0014] Beneficial effects of the present invention: 1) The UV curing material prepared by the technical solution of the present invention has a very good flame retardant effect, with an LOI of 26.5~33.2% and a flame retardant grade of V-1~V-0; 2) The UV curing material prepared by the technical solution of the present invention has a pencil hardness of 2B~9H and an initial thermal decomposition temperature of 246.0~298.2°C, and can be used as flame retardant three-proof paint for electronic components, flame retardant industrial paint, flame retardant tent cloth coating, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The tetrahydroxy SPDPC derivative obtained in the preparation process of the hydroxy derivative of dispirocyclic pentaerythritol diphosphate 1 H NMR spectrum; Figure 2 This is the FT-IR spectrum of the tetrahydroxy SPDPC derivative obtained in the preparation process of the hydroxy derivative of dispirocyclopentaerythritol diphosphate. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in 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.

[0017] The present invention provides a method for preparing a UV-curable polyurethane with synergistic flame retardancy of a bispirocyclic phosphate and silicone, comprising the following steps: The hydroxyl derivative of dispirocyclic pentaerythritol diphosphate and hydroxyl-terminated polysiloxane are added together into a three-necked flask equipped with a mechanical stirrer and a thermometer, and after being stirred evenly, dibutyltin dilaurate and diisocyanate are added dropwise, and the mixture is reacted at 40-80° C. for 4-6 hours, and then hydroxypropyl methacrylate is added, and the mixture is reacted at 40-80° C. for 4-8 hours to obtain a polyurethane prepolymer containing dispirocyclic phosphate and silicone; Then, 1-10 wt% of the prepolymer mass of ultraviolet light initiator is added, and UV curing is performed to obtain the UV-cured polyurethane with synergistic flame retardancy of the bispirocyclic phosphate and silicone.

[0018] Here, the hydroxy derivative of dispirocyclic pentaerythritol diphosphate is a liquid tetrahydroxy SPDPC derivative, and its preparation process is as follows: Step 1, pentaerythritol and phosphorus oxychloride are added to a three-necked flask in a molar ratio of 1:2, and the temperature is raised to 100°C for reaction for 12 hours under stirring. The tail gas is absorbed by a saturated NaOH solution. After the reaction is completed, it is cooled to room temperature and filtered with a Buchner funnel to obtain a white solid, which is then washed with anhydrous dichloromethane and dried in a vacuum oven at 60°C to constant weight to obtain a white solid powder SPDPC. The specific reaction formula is as follows: ; Step 2, dissolve SPDPC in anhydrous acetonitrile of equal mass, and dropwise add 2 times molar amount of diethanolamine and 2 times molar amount of triethylamine in anhydrous acetonitrile solution, then react at 60°C for 2 h, then heat and reflux for 12 h, cool and filter, and remove acetonitrile from the filtrate under reduced pressure to obtain a liquid tetrahydroxy SPDPC derivative. The specific reaction formula is as follows: .

[0019] The molecular formula of hydroxyl-terminated polysiloxane is HOMe2SiO(Me2SiO) n SiMe2OH, wherein n is an integer from 10 to 500.

[0020] The obtained liquid tetrahydroxy SPDPC derivative 1 H NMR spectra and FT-IR spectra are shown in Figure 1 , 2 shown. Example 1

[0021] This example provides a UV-curable polyurethane with synergistic flame retardancy of a bis-spirocyclic phosphate and silicone, and the preparation method thereof is as follows: 1) Add 136.146g of pentaerythritol and 306.66g of phosphorus oxychloride to a three-necked flask, heat to 100℃ and react for 12 h under stirring, and absorb the tail gas with saturated NaOH solution. After the reaction, cool to room temperature, filter with a Buchner funnel to obtain a white solid, wash with anhydrous dichloromethane and dry in a vacuum oven at 60℃ to constant weight to obtain 136.62g of white solid powder SPDPC. Dissolve SPDPC in 136.62g of anhydrous acetonitrile, and add 96.725g of diethanolamine and 400ml of anhydrous acetonitrile solution containing 93.095g of triethylamine dropwise, then react at 60℃ for 2 h, heat and reflux for 12 h, cool and filter, remove acetonitrile from the filtrate under reduced pressure, and obtain 369.13g of liquid tetrahydroxy SPDPC derivative; 2) First, 21.7g of liquid tetrahydroxy SPDPC derivative, 370.9g of HO(Me2SiO) 100 H were added into a 500mL three-necked flask equipped with a mechanical stirrer and a thermometer. After stirring evenly, 1.57g of dibutyltin dilaurate and 55.50g of IPDI were added dropwise. After reacting at 40°C for 6h, 28.834g of hydroxypropyl methacrylate was added. The reaction was continued at 40°C for 8h to obtain 476.934g of a bispirocyclic phosphate and silicone polyurethane prepolymer.

[0022] 3) The prepared bispirocyclic phosphate and silicone polyurethane prepolymer was added with UV initiator 1173 to prepare a UV curing material, as shown in Table 1.

[0023] Table 1 Effect of UV initiator 1173 dosage and curing time

[0024] The above usage percentage of initiator 1173 is based on the bispirocyclic phosphate and silicone polyurethane prepolymer.

[0025] Pencil hardness: Determine according to GB / T 6739-2006 “Paints and varnishes - Determination of film hardness by pencil method”.

[0026] LOI (Limiting Oxygen Index) Determination: According to ASTM-D2863 standard, use HC-3 oxygen index meter to measure the UV curing material (size 80×10×4mm 3 )'s limiting oxygen index.

[0027] The flame retardant rating is measured according to the UL94 vertical burning test method.

[0028] As can be seen from Table 1, from numbers 1 to 5, under the same other conditions, when the dosage of UV initiator 1173 is between 1-10%, the pencil hardness gradually increases with the increase of the initiator dosage. When the initiator dosage reaches 5%, the pencil hardness remains at 9H, and the initial thermal decomposition temperature gradually increases. It is the highest when the initiator dosage is 5%, and then decreases with the increase of the initiator dosage. LOI increases with the increase of the initiator dosage. When the initiator dosage reaches 5%, LOI is the highest, and then gradually decreases.

[0029] It can be seen from No. 6-11 that, under the same other conditions, the pencil hardness gradually increases as the curing time increases from 20s to 120s, and remains unchanged after the curing time reaches 90s; the initial thermal decomposition temperature also gradually increases with the extension of the curing time, reaches the highest point when the curing time reaches 90s, and then decreases; LOI also increases with the extension of the curing time, reaches the highest point when the curing time reaches 90s, and then gradually decreases. Example 2

[0030] This example provides a UV-curable polyurethane with synergistic flame retardancy of a bis-spirocyclic phosphate and silicone, and the preparation method thereof is as follows: 1) According to the feed ratio shown in Table 2, first take the liquid tetrahydroxy SPDPC derivative prepared in step 1) of Example 1, 370.9 g HO(Me2SiO) 100 H are added into a 500mL three-necked flask equipped with a mechanical stirrer and a thermometer. After stirring evenly, 0.4% of the total mass of the raw materials, dibutyltin dilaurate, and IPDI are added dropwise. After reacting at 40°C for 6h, hydroxypropyl methacrylate is added, and the reaction is continued at 40°C for 8h to obtain a bispirocyclic phosphate and silicone polyurethane prepolymer.

[0031] 2) The prepared bispirocyclic phosphate and silicone polyurethane prepolymer was added with UV initiator 1173, the dosage of UV initiator 1173 was 5%, the curing time was 60s, and a UV curing material was prepared, as shown in Table 2.

[0032] Table 2 Effect of tetrahydroxy SPDPC derivatives and quality and IPDI feed ratio

[0033] It can be seen from No. 1-3 in Table 2 that the pencil hardness decreases and the limiting oxygen index (LOI) increases as the molar ratio of the isocyanate group in IPDI to the hydroxyl group in the mixture of the hydroxyl derivative of dispirocyclopentaerythritol diphosphate and the hydroxyl-terminated polysiloxane decreases. Example 3

[0034] This example provides a UV-curable polyurethane with synergistic flame retardancy of a bis-spirocyclic phosphate and silicone, and the preparation method thereof is as follows: 1) First, 21.7 g of the liquid tetrahydroxy SPDPC derivative prepared in step 1) of Example 1 and terminal hydroxyl polysiloxanes of different molecular weights were added into a three-necked flask equipped with a mechanical stirrer and a thermometer. After stirring evenly, 0.4% of the total weight of the raw materials, dibutyltin dilaurate, and IPDI were added dropwise. After reacting at 40° C. for 6 h, hydroxypropyl methacrylate was added, and the reaction was continued at 40° C. for 8 h to obtain a bispirocyclic phosphate and silicone polyurethane prepolymer.

[0035] 2) The prepared bispirocyclic phosphate and silicone polyurethane prepolymer was added with UV initiator 1173, the dosage of UV initiator 1173 was 5%, the curing time was 60s, and a UV curing material was prepared, as shown in Table 3.

[0036] Table 3 Effect of different molecular weight hydroxyl-terminated polysiloxanes and their dosage

[0037] From the numbers 1-5 in Table 3, it can be seen that although the ratio between the molar amount of isocyanate groups in IPDI and the molar amount of hydroxyl groups in the mixture of the hydroxyl derivative of dispirocyclopentaerythritol diphosphate and the hydroxyl-terminated polysiloxane has not changed, the increase in the amount of hydroxyl-terminated polysiloxane has increased the content of SiO-, decreased the pencil hardness, gradually decreased the initial thermal decomposition temperature, and decreased the limiting oxygen index (LOI). n When n=100 in SiMe2OH, various properties are relatively good. It can be seen from No. 6-8 in Table 3 that as the molar ratio of the isocyanate group in IPDI to the hydroxyl molar ratio of the mixture of the hydroxyl derivative of dispirocyclopentaerythritol diphosphate and the hydroxyl-terminated polysiloxane exceeds 3:1 and gradually increases, the pencil hardness, initial thermal decomposition temperature and limiting oxygen index (LOI) all decrease significantly, and the flame retardant grade also changes from V-0 to V-1.

[0038] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for preparing a UV-curable polyurethane with synergistic flame retardancy of a bispirocyclic phosphate and silicone, characterized in that: The following steps are involved: The hydroxyl derivative of dispirocyclic pentaerythritol diphosphate and hydroxyl-terminated polysiloxane are added together into a three-necked flask equipped with a mechanical stirrer and a thermometer, and after being stirred evenly, dibutyltin dilaurate and diisocyanate are added dropwise, and the mixture is reacted at 40-80° C. for 4-6 hours, and then hydroxypropyl methacrylate is added, and the mixture is reacted at 40-80° C. for 4-8 hours to obtain a polyurethane prepolymer containing dispirocyclic phosphate and silicone; Then, 1-10 wt% of the prepolymer mass of ultraviolet light initiator is added, and UV curing is performed to obtain the UV-cured polyurethane with synergistic flame retardancy of the bispirocyclic phosphate and silicone.

2. The method for preparing a UV-curable polyurethane with synergistic flame retardancy of a bispirocyclic phosphate and silicone according to claim 1, characterized in that: The hydroxy derivative of the dispirocyclic pentaerythritol diphosphate is a liquid tetrahydroxy SPDPC derivative, and its preparation steps are as follows: Step 1, pentaerythritol and phosphorus oxychloride are added to a three-necked flask in a molar ratio of 1:2, and the mixture is heated to 100°C with stirring for 12 hours. The tail gas is absorbed by a saturated NaOH solution. After the reaction is completed, the mixture is cooled to room temperature and filtered through a Buchner funnel to obtain a white solid, which is then washed with anhydrous dichloromethane and dried in a vacuum oven at 60°C to constant weight to obtain a white solid powder SPDPC. The specific reaction formula is as follows: ； Step 2, dissolve SPDPC in anhydrous acetonitrile of equal mass, and dropwise add 2 times molar amount of diethanolamine and 2 times molar amount of triethylamine in anhydrous acetonitrile solution, then react at 60°C for 2 h, then heat and reflux for 12 h, cool and filter, and remove acetonitrile from the filtrate under reduced pressure to obtain a liquid tetrahydroxy SPDPC derivative. The specific reaction formula is as follows: 。 3. The method for preparing a UV-curable polyurethane with synergistic flame retardancy of a bis-spirocyclic phosphate and silicone according to claim 1, characterized in that: The molecular structure of the hydroxyl-terminated polysiloxane is HOMe2SiO(Me2SiO) n SiMe2OH, wherein n is an integer from 10 to 500.

4. The method for preparing a UV-curable polyurethane with synergistic flame retardancy of a bis-spirocyclic phosphate and silicone according to claim 1, characterized in that: In the process of preparing the bispirocyclic phosphate and silicone polyurethane prepolymer, diisocyanate and a mixture of a hydroxyl derivative of bispirocyclic pentaerythritol diphosphate and a hydroxyl-terminated polysiloxane are added at a molar ratio of isocyanate group to hydroxyl group of 3:1 to 1.2:1; The molar ratio of the hydroxy derivative of dispirocyclopentaerythritol diphosphate to the hydroxyl-terminated polysiloxane is 0.05:1-1:

1.

5. The method for preparing a UV-curable polyurethane with synergistic flame retardancy of a bis-spirocyclic phosphate and silicone according to claim 1, characterized in that: In the process of preparing the polyurethane prepolymer containing bispirocyclic phosphate and silicone, the addition amount of dibutyltin dilaurate is 0.4% of the total mass of the hydroxyl derivative of bispirocyclic pentaerythritol diphosphate and the hydroxyl-terminated polysiloxane.

6. The method for preparing a UV-curable polyurethane with synergistic flame retardancy of a bis-spirocyclic phosphate and silicone according to claim 1, characterized in that: The diisocyanate is one or more of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate isomer mixture, diphenylmethane diisocyanate, 1,6-hexamethylene diisocyanate, and isophorone diisocyanate.

7. A UV-curable polyurethane with synergistic flame retardancy of bis-spirocyclic phosphate and organosilicon prepared by the method for preparing UV-curable polyurethane with synergistic flame retardancy of bis-spirocyclic phosphate and organosilicon according to any one of claims 1 to 6.

8. The UV-curable polyurethane with synergistic flame retardancy of bispirocyclic phosphate and silicone according to claim 7, characterized in that: The pencil hardness of the UV-curable polyurethane with synergistic flame retardancy of the bispirocyclic phosphate and silicone is 2B-9H, the initial thermal decomposition temperature is 246.0-298.2°C, and the limiting oxygen index is 26.0-33.2%.

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