Polyurethane adhesive with fluorine-containing side chain and preparation method thereof

Abstract

The invention discloses a polyurethane adhesive with a fluorine-containing side chain and a preparation method thereof, and relates to a polyurethane adhesive and a preparation method thereof. The invention aims to solve the problem that energy loss is caused by reduction of AP high-energy components due to the fact that common fluorine-containing polymers such as PVDF and PTFE are usually added in the form of an oxidizing agent due to limitation of inherent characteristics of the fluorine-containing polymers. The preparation method comprises the following steps: step 1, purging a reaction container for 30 minutes by using high-purity nitrogen, adding an initiator and a solvent, adding a catalyst A, and mixing and reacting for 10-60 minutes; step 2, dropwise adding a fluorine-containing oxetane monomer into the reaction liquid; step 3, adding branched-chain fluorine-containing hydroxyl-terminated polyether PFOH, diisocyanate and triisocyanate into the container, stirring for 5-30 minutes, adding a catalyst B, uniformly stirring, pouring into a silica gel mold, and putting into a vacuum oven at room temperature to remove bubbles; and step 4, putting the mold into a heating oven. The invention belongs to the technical field of polyurethane synthesis.

Description

Technical Field

[0001] The invention relates to a polyurethane adhesive and a preparation method thereof, belonging to the technical field of polyurethane synthesis. Background Art

[0002] Polyurethane material is a commonly used adhesive in solid propellants. It is used to encapsulate components such as combustion agents, oxidants and plasticizers through curing and cross-linking of components such as oligomer polyols and polyisocyanates, providing overall mechanical properties and combustibles. However, due to its inert nature (almost only containing C and H elements), traditional HTPB-based polyurethane adhesives limit the energy output of the system. At the same time, aluminum powder has serious agglomeration and sintering phenomena under high Al content, resulting in two-phase flow loss and engine specific impulse reduction, and the gain effect of aluminum powder cannot be fully exerted.

[0003] Fluoropolymers have attracted great attention in the field of energetic materials due to their advantages such as high density, low friction coefficient, excellent environmental stability and good compatibility with polar fillers. At the same time, fluoropolymers have a special energy release effect when burning with aluminum powder. They can not only react with active aluminum to produce AlF3 that is easier to vaporize at high temperatures and a large amount of heat, but also react with the inert Al2O3 shell to generate AlF3 and release a large amount of heat to promote the main combustion reaction. They can effectively inhibit the agglomeration and sintering of aluminum powder during combustion and improve the energy release level of the propellant. However, due to the limitations of their inherent properties, common fluoropolymers such as PVDF and PTFE are usually added in the form of oxidants, resulting in a reduction in high-energy components of AP and energy loss. Therefore, the development of new fluorinated polyurethane adhesives to replace traditional inert HTPB-based polyurethane adhesives is expected to solve the above problems. Summary of the invention

[0004] The present invention aims to solve the problem that common fluorinated polymers such as PVDF and PTFE are usually added in the form of oxidants due to the limitations of their inherent properties, resulting in a reduction in high-energy components of AP and causing energy loss, and further proposes a polyurethane adhesive with fluorinated side chains and a preparation method thereof.

[0005] The technical solution adopted by the present invention to solve the above problems is: the structural formula of the polyurethane adhesive of the present invention is:

[0006]

[0007] R1, R2 are hydrocarbon groups, -OR f -O- is

[0008] Wherein, x is 0 or a positive integer, and y and n are positive integers.

[0009] The steps of the polyurethane adhesive preparation method of the present invention include:

[0010] Step 1: Use high-purity nitrogen to purge the reaction vessel for 30 minutes to remove the air inside the reaction device, add initiator and solvent, control the reaction temperature at 0-30°C, stir magnetically until it is evenly dissolved, add catalyst A and mix and react for 10-60 minutes;

[0011] Step 2, adding the fluorinated oxetane monomer dropwise to the reaction solution for 1 to 4 hours, and after the addition is complete, continuing to react at a constant temperature for 2 to 30 hours, washing and separating the organic phase, and rotary evaporating to obtain a branched fluorinated hydroxyl-terminated polyether PFOH;

[0012] Step 3, add branched fluorinated hydroxyl-terminated polyether PFOH, diisocyanate and triisocyanate into a container and stir for 5 to 30 minutes, then add catalyst B and stir evenly, pour into a silicone mold, and place in a vacuum oven at room temperature to remove bubbles;

[0013] Step 4: Place the mold in a heating oven, control the temperature to 30-90° C., heat for 8-72 hours for curing, and obtain a polyurethane adhesive with fluorine-containing side chains.

[0014] Furthermore, the polyurethane adhesive having fluorine-containing side chains is obtained by stepwise polymerization of fluorine-containing terminal hydroxyl polyether PFOH and polyisocyanate.

[0015] Furthermore, the molar ratio of the initiator, the catalyst A, and the fluorinated oxetane is (1-4): (2-4): (4-20), and the solvent is added in an amount to prepare a fluorinated oxetane solution with a molar concentration of 1-10 mol / L.

[0016] Furthermore, the initiator is composed of one or more of 1,2-propylene glycol and 1,3-propylene glycol.

[0017] Furthermore, the solvent is composed of one or more of dichloromethane, dichloroethane, chloroform, ethyl acetate, dimethyl carbonate, methyl formate, and acetone.

[0018] Furthermore, the catalyst A is composed of one or more of boron trifluoride diethyl ether, boron trifluoride tetrahydrofuran complex, stannous octoate, triethylaluminum, and triisobutylaluminum.

[0019] Further, the fluorine-containing oxetane is composed of one or more of 3,3-bis(2,2,2-trifluoroethoxymethyl)oxetane, 3,3-bis(2,2,3,3,3-pentafluoropropoxymethyl)oxetane, 3,3-bis(2,2,3,3,4,4,4-heptafluorobutoxymethyl)oxetane, 3,3-bis(2,2,3,3,4,4,5,5,5-nonafluoropentyloxymethyl)oxetane and 3,3-bis(2,2,3,3,4,4,5,5,6,6,6-undecenofluorohexyloxymethyl)oxetane.

[0020] Furthermore, the molar ratio of the branched fluorinated hydroxyl-terminated polyether PFOH, diisocyanate and triisocyanate is 1:(0.4-0.8):(0.1-0.7), and the amount of catalyst B is 0.05% of the total mass of PFOH, diisocyanate and triisocyanate.

[0021] Further, the diisocyanate is composed of one or more of p-phenylene diisocyanate, m-phenylenediisocyanate, trimethylhexamethylene diisocyanate, 1,3-phenylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, toluene-2,4-diisocyanate, and toluene-2,5-diisocyanate;

[0022] The triisocyanate is composed of one or more of triphenylmethane triisocyanate, triphenyl isocyanate thiophosphate, 1,3,5-tris(6-isocyanatohexyl) biuret, and hexamethylene diisocyanate trimer;

[0023] Catalyst B is composed of one or more of dibutyltin dilaurate, stannous octoate, triphenylbismuth, lead isooctanoate, zinc isooctanoate and triethylenediamine.

[0024] The beneficial effects of the present invention are:

[0025] 1. The polyurethane adhesive with fluorine-containing side chains provided by the present invention is obtained by stepwise polymerization of fluorine-containing terminal hydroxyl polyether PFOH and isocyanate monomers. The synthesis process is simple and efficient and can be industrially prepared.

[0026] 2. The polyurethane adhesive with fluorine-containing side chains provided in the present application can effectively inhibit the agglomeration and sintering of aluminum powder during combustion and improve the energy output level of solid propellant. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is the FTIR graph of the polyurethane adhesive having fluorine-containing side chains prepared in Example 1;

[0028] Figure 2 is a schematic diagram of the DSC test results of the polyurethane adhesive having fluorine-containing side chains prepared in Example 1;

[0029] Figure 3 Schematic diagram of the tensile test results of the polyurethane adhesive with fluorine-containing side chains prepared in Examples 1 and 2. Example

[0030] Example 1

[0031] 1,2-propylene glycol, boron trifluoride diethyl ether, and 3,3-bis(2,2,2-trifluoroethoxymethyl)oxetane are taken in a molar ratio of 3:1:8 respectively, and corresponding dichloromethane is taken to prepare a 2 mol / L 3,3-bis(2,2,2-trifluoroethoxymethyl)oxetane solution.

[0032] The branched fluorinated hydroxyl-terminated polyether PFOH, m-xylene diisocyanate and triphenylmethane triisocyanate are taken in a molar ratio of 1:0.5:0.4 respectively, and the amount of dibutyltin dilaurate is 0.05% of the total mass of PFOH, m-xylene diisocyanate and triphenylmethane triisocyanate.

[0033] The method for producing a polyurethane adhesive having a fluorine-containing side chain comprises the following steps:

[0034] (1) Use high-purity nitrogen to purge the reaction container for 30 minutes to remove the air inside the reaction device, add 1,2-propylene glycol and dichloromethane, control the reaction temperature at 0°C, stir magnetically until the solution is uniform, add boron trifluoride diethyl ether and mix and react for 20 minutes;

[0035] (2) adding 3,3-bis(2,2,2-trifluoroethoxymethyl)oxetane monomer dropwise to the reaction solution for 1.5 hours. After the addition is complete, the temperature is kept constant for 6 hours. The organic phase is washed and separated, and the branched fluorinated hydroxyl-terminated polyether PFOH is obtained by rotary evaporation.

[0036] (3) Add branched fluorinated hydroxyl-terminated polyether PFOH, m-xylene diisocyanate, and triphenylmethane triisocyanate into a container and stir for 10 minutes, then add dibutyltin dilaurate and stir evenly, then pour into a silicone mold and place in a vacuum oven at room temperature to remove bubbles;

[0037] (4) The mold is placed in a heating oven, the temperature is controlled at 60° C., and the mold is heated for 12 hours for curing to obtain a polyurethane adhesive having fluorine-containing side chains.

[0038] Example 2

[0039] 1,2-propylene glycol, boron trifluoride diethyl ether, and 3,3-bis(2,2,2-trifluoroethoxymethyl)oxetane were taken in a molar ratio of 3:1:5, and the corresponding dichloroethane was taken to prepare a 3 mol / L 3,3-bis(2,2,2-trifluoroethoxymethyl)oxetane solution.

[0040] The branched fluorinated hydroxyl-terminated polyether PFOH, trimethyl hexamethylene diisocyanate and triphenylmethane triisocyanate are taken in a molar ratio of 1:0.5:0.4 respectively, and the amount of dibutyltin dilaurate is 0.05% of the total mass of PFOH, trimethyl hexamethylene diisocyanate and triphenylmethane triisocyanate.

[0041] The method for producing a polyurethane adhesive having a fluorine-containing side chain comprises the following steps:

[0042] (1) Use high-purity nitrogen to purge the reaction container for 30 minutes to remove the air inside the reaction device, add 1,2-propylene glycol and dichloroethane, control the reaction temperature at 0°C, stir magnetically until the solution is uniform, add boron trifluoride diethyl ether and mix and react for 20 minutes;

[0043] (2) adding 3,3-bis(2,2,2-trifluoroethoxymethyl)oxetane monomer dropwise to the reaction solution for 1 hour. After the addition is complete, the temperature is kept constant for 6 hours. The organic phase is washed and separated, and the branched fluorinated hydroxyl-terminated polyether PFOH is obtained by rotary evaporation.

[0044] (3) Add branched fluorinated hydroxyl-terminated polyether PFOH, trimethylhexane diisocyanate, and triphenylmethane triisocyanate into a container and stir for 15 minutes, then add dibutyltin dilaurate and stir evenly, then pour into a silicone mold and place in a vacuum oven at room temperature to remove bubbles;

[0045] (4) The mold was placed in a heating oven, the temperature was controlled at 65° C., and the mold was heated for 16 hours for curing to obtain a polyurethane adhesive having fluorine-containing side chains.

[0046] Example 3

[0047] 1,2-propylene glycol, boron trifluoride tetrahydrofuran complex, and 3,3-bis(2,2,3,3,3-pentafluoropropoxymethyl)oxetane are taken in a molar ratio of 4:1:10, and corresponding dichloroethane is taken to prepare a 3 mol / L 3,3-bis(2,2,3,3,3-pentafluoropropoxymethyl)oxetane solution.

[0048] The branched fluorine-terminated hydroxyl polyether PFOH, p-phenylene diisocyanate and triphenylmethane triisocyanate are respectively taken in a molar ratio of 1:0.6:0.3, and the amount of triphenylbismuth is 0.05% of the total mass of PFOH, p-phenylene diisocyanate and triphenylmethane triisocyanate.

[0049] The method for producing a polyurethane adhesive having a fluorine-containing side chain comprises the following steps:

[0050] (1) using high-purity nitrogen to purge the reaction vessel for 30 minutes to remove the air inside the reaction device, adding 1,2-propylene glycol and ethylene dichloride, controlling the reaction temperature at 0°C, performing magnetic stirring until the solution is uniform, adding boron trifluoride tetrahydrofuran complex and mixing for 30 minutes;

[0051] (2) adding 3,3-bis(2,2,3,3,3-pentafluoropropoxymethyl)oxetane monomer dropwise to the reaction solution for 2 hours. After the addition is complete, the temperature is kept constant for 12 hours. The organic phase is washed and separated, and the branched fluorinated hydroxyl-terminated polyether PFOH is obtained by rotary evaporation.

[0052] (3) adding branched fluorinated hydroxyl-terminated polyether PFOH, p-phenylene diisocyanate, and triphenylmethane triisocyanate to a container and stirring for 20 minutes, then adding triphenyl bismuth and stirring evenly, pouring into a silicone mold, and placing in a vacuum oven at room temperature to remove bubbles;

[0053] (4) The mold is placed in a heating oven, the temperature is controlled at 70° C., and the mold is heated for 24 hours for curing to obtain a polyurethane adhesive having fluorine-containing side chains.

[0054] Example 4

[0055] 1,3-Propanediol, boron trifluoride tetrahydrofuran complex, 3,3-bis(2,2,3,3,4,4,4-heptafluorobutoxymethyl)oxetane were taken in a molar ratio of 4:1:15, and the corresponding ethyl acetate was taken to prepare 5 mol / L 3,3-bis(2,2,3,3,4,4,4

[0056] -heptafluorobutoxymethyl)oxetane solution.

[0057] The branched fluorinated hydroxyl-terminated polyether PFOH, 1,3-phenylene diisocyanate and triphenyl isocyanate of thiophosphate are respectively taken in a molar ratio of 1:0.4:0.6, and the amount of triphenyl bismuth is 0.05% of the total mass of PFOH, 1,3-phenylene diisocyanate and triphenyl isocyanate of thiophosphate.

[0058] The method for producing a polyurethane adhesive having a fluorine-containing side chain comprises the following steps:

[0059] (1) using high-purity nitrogen to purge the reaction vessel for 30 minutes to remove the air inside the reaction device, adding 1,3-propylene glycol and ethyl acetate, controlling the reaction temperature at 10° C., performing magnetic stirring until the solution is uniform, adding boron trifluoride tetrahydrofuran complex and mixing for 30 minutes;

[0060] (2) adding 3,3-bis(2,2,3,3,4,4,4-heptafluorobutoxymethyl)oxetane monomer dropwise to the reaction solution for 2 hours. After the addition is complete, the temperature is kept constant for 16 hours. The organic phase is washed and separated, and the branched fluorinated hydroxyl-terminated polyether PFOH is obtained by rotary evaporation.

[0061] (3) adding branched fluorinated hydroxyl-terminated polyether PFOH, 1,3-phenylene diisocyanate, and triphenyl isocyanate of thiophosphate to a container and stirring for 30 minutes, then adding triphenyl bismuth and stirring evenly, pouring into a silica gel mold, and placing in a vacuum oven at room temperature to remove bubbles;

[0062] (4) The mold was placed in a heating oven, the temperature was controlled at 70° C., and the mold was heated for 36 hours for curing to obtain a polyurethane adhesive having fluorine-containing side chains.

[0063] Example 5

[0064] 1,3-Propanediol, stannous octoate and 3,3-bis(2,2,3,3,4,4,5,5,5-nonafluoropentyloxymethyl)oxetane are taken in a molar ratio of 2:2:10 respectively, and the corresponding ethyl acetate is taken to prepare a 5 mol / L 3,3-bis(2,2,3,3,4,4,5,5,5-nonafluoropentyloxymethyl)oxetane solution.

[0065] The branched fluorinated hydroxyl-terminated polyether PFOH, hexamethylene diisocyanate and triphenyl isocyanate of thiophosphate are respectively taken in a molar ratio of 1:0.6:0.4, and the amount of triphenyl bismuth is 0.05% of the total mass of PFOH, hexamethylene diisocyanate and triphenyl isocyanate of thiophosphate.

[0066] The method for producing a polyurethane adhesive having a fluorine-containing side chain comprises the following steps:

[0067] (1) using high-purity nitrogen to purge the reaction vessel for 30 minutes to remove the air inside the reaction device, adding 1,3-propylene glycol and ethyl acetate, controlling the reaction temperature at 15° C., performing magnetic stirring until the solution is uniform, adding stannous octoate and mixing for 40 minutes;

[0068] (2) adding 3,3-bis(2,2,3,3,4,4,5,5,5-nonafluoropentyloxymethyl)oxetane monomer dropwise to the reaction solution for 2 hours. After the addition is complete, the temperature is kept constant for 20 hours. The organic phase is washed and separated, and the branched fluorinated hydroxyl-terminated polyether PFOH is obtained by rotary evaporation.

[0069] (3) adding branched fluorinated hydroxyl-terminated polyether PFOH, hexamethylene diisocyanate, and triphenyl isocyanate of thiophosphate to a container and stirring for 30 minutes, then adding triphenyl bismuth and stirring evenly, pouring into a silicone mold, and placing in a vacuum oven at room temperature to remove bubbles;

[0070] (4) The mold is placed in a heating oven, the temperature is controlled at 75° C., and the mold is heated for 48 hours for curing to obtain a polyurethane adhesive having fluorine-containing side chains.

[0071] Example 6

[0072] 1,3-propylene glycol, triethylaluminum, 3,3-bis(2,2,3,3,4,4,5,5,6,6,6-undecenefluorohexyloxymethyl)oxetane and corresponding dimethyl carbonate are taken in a molar ratio of 1:2:12 to prepare a 4 mol / L 3,3-bis(2,2,3,3,4,4,5,5,6,6,6-undecenefluorohexyloxymethyl)oxetane solution.

[0073] The branched fluorinated hydroxyl-terminated polyether PFOH, toluene-2,4-diisocyanate and hexamethylene diisocyanate trimer are respectively taken in a molar ratio of 1:0.8:0.6, and the amount of stannous octoate used is 0.05% of the total mass of PFOH, toluene-2,4-diisocyanate and hexamethylene diisocyanate trimer.

[0074] The method for producing a polyurethane adhesive having a fluorine-containing side chain comprises the following steps:

[0075] (1) using high-purity nitrogen to purge the reaction vessel for 30 minutes to remove the air inside the reaction device, adding 1,3-propylene glycol and dimethyl carbonate, controlling the reaction temperature at 20° C., performing magnetic stirring until the solution is uniform, adding triethylaluminum and mixing for 50 minutes;

[0076] (2) adding 3,3-bis(2,2,3,3,4,4,5,5,6,6,6-undecylfluorohexyloxymethyl)oxetane monomer dropwise to the reaction solution for 4 hours. After the addition is complete, the temperature is kept constant for 24 hours. The organic phase is washed and separated, and the branched fluorinated hydroxyl-terminated polyether PFOH is obtained by rotary evaporation.

[0077] (3) Add branched fluorinated hydroxyl-terminated polyether PFOH, toluene-2,4-diisocyanate, and hexamethylene diisocyanate trimer into a container and stir for 30 minutes, then add stannous octoate and stir evenly, then pour into a silicone mold and place in a vacuum oven at room temperature to remove bubbles;

[0078] (4) The mold was placed in a heating oven, the temperature was controlled at 75° C., and the mold was heated for 72 hours for curing to obtain a polyurethane adhesive having fluorine-containing side chains.

[0079] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent replacement and improvement made to the above embodiments without departing from the content of the technical solution of the present invention, based on the technical essence of the present invention, within the spirit and principles of the present invention, still fall within the protection scope of the technical solution of the present invention.

Claims

1. A polyurethane adhesive having a fluorine-containing side chain, characterized in that: The structural formula is: R1, R2 are hydrocarbon groups, -OR f -O- is Wherein, x is 0 or a positive integer, and y and n are positive integers.

2. A method for preparing a polyurethane adhesive having a fluorine-containing side chain, characterized in that: The specific steps include: Step 1: Use high-purity nitrogen to purge the reaction vessel for 30 minutes to remove the air inside the reaction device, add initiator and solvent, control the reaction temperature at 0-30°C, stir magnetically until it is evenly dissolved, add catalyst A and mix and react for 10-60 minutes; Step 2, adding the fluorinated oxetane monomer dropwise to the reaction solution for 1 to 4 hours, and after the addition is complete, continuing to react at a constant temperature for 2 to 30 hours, washing and separating the organic phase, and rotary evaporating to obtain a branched fluorinated hydroxyl-terminated polyether PFOH; Step 3, add branched fluorinated hydroxyl-terminated polyether PFOH, diisocyanate and triisocyanate into a container and stir for 5 to 30 minutes, then add catalyst B and stir evenly, pour into a silicone mold, and place in a vacuum oven at room temperature to remove bubbles; Step 4: Place the mold in a heating oven, control the temperature to 30-90° C., heat for 8-72 hours for curing, and obtain a polyurethane adhesive with fluorine-containing side chains.

3. The method for preparing a polyurethane adhesive having a fluorine-containing side chain according to claim 2, characterized in that: The polyurethane adhesive with fluorine-containing side chains is obtained by stepwise polymerization of fluorine-containing terminal hydroxyl polyether PFOH and polyisocyanate.

4. The method for preparing a polyurethane adhesive having a fluorine-containing side chain according to claim 2, characterized in that: The molar ratio of the initiator, the catalyst A and the fluorinated oxetane is (1-4): (2-4): (4-20), and the solvent is added in an amount to prepare a fluorinated oxetane solution with a molar concentration of 1-10 mol / L.

5. The method for preparing a polyurethane adhesive having a fluorine-containing side chain according to claim 2, characterized in that: The initiator is composed of one or more of 1,2-propylene glycol and 1,3-propylene glycol.

6. The method for preparing a polyurethane adhesive having a fluorine-containing side chain according to claim 2, characterized in that: The solvent is composed of one or more of dichloromethane, dichloroethane, chloroform, ethyl acetate, dimethyl carbonate, methyl formate and acetone.

7. The method for preparing a polyurethane adhesive having a fluorine-containing side chain according to claim 2, characterized in that: Catalyst A is composed of one or more of boron trifluoride diethyl ether, boron trifluoride tetrahydrofuran complex, stannous octoate, triethylaluminum, and triisobutylaluminum.

8. The method for preparing a polyurethane adhesive having a fluorine-containing side chain according to claim 2, characterized in that: The fluorine-containing oxetane is composed of one or more of 3,3-bis(2,2,2-trifluoroethoxymethyl)oxetane, 3,3-bis(2,2,3,3,3-pentafluoropropoxymethyl)oxetane, 3,3-bis(2,2,3,3,4,4,4-heptafluorobutoxymethyl)oxetane, 3,3-bis(2,2,3,3,4,4,5,5,5-nonafluoropentyloxymethyl)oxetane and 3,3-bis(2,2,3,3,4,4,5,5,6,6,6-undecenofluorohexyloxymethyl)oxetane.

9. The method for preparing a polyurethane adhesive having fluorine-containing side chains according to claim 2, characterized in that: The molar ratio of the branched fluorine-containing terminal hydroxyl polyether PFOH, diisocyanate and triisocyanate is 1:(0.4-0.8):(0.1-0.7), and the amount of catalyst B is 0.05% of the total mass of PFOH, diisocyanate and triisocyanate.

10. The method for preparing a polyurethane adhesive having fluorine-containing side chains according to claim 2, characterized in that: The diisocyanate is composed of one or more of p-phenylene diisocyanate, m-phenylene diisocyanate, trimethyl hexamethylene diisocyanate, 1,3-phenylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, toluene-2,4-diisocyanate and toluene-2,5-diisocyanate; The triisocyanate is composed of one or more of triphenylmethane triisocyanate, triphenyl isocyanate thiophosphate, 1,3,5-tris(6-isocyanatohexyl) biuret, and hexamethylene diisocyanate trimer; Catalyst B is composed of one or more of dibutyltin dilaurate, stannous octoate, triphenylbismuth, lead isooctanoate, zinc isooctanoate and triethylenediamine.

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