Halogen-free supramolecular flame retardant for polyurethane foam and preparation method of halogen-free supramolecular flame retardant

Abstract

The invention provides a halogen-free supramolecular flame retardant for polyurethane foam. The flame retardant is a compound with a primary amino terminal group, wherein the compound is prepared from polyamine and dichlorophosphonyl substances through a solvent condensation reaction. According to the invention, due to the hydrogen-bond interaction formed by the cross-linked supramolecular phosphorus-nitrogen polymer and polyurethane, tight combination is realized, and flame-retardant elements are introduced into the condensed phase of polyurethane molecules through blending, so that the dual effects of condensed phase flame retardance and gas phase flame retardance are achieved. Therefore, in the use process, the reduction of the flame-retardant function caused by migration and precipitation of the flame retardant is reduced, and the flame-retardant effect is lasting. Therefore, the polyurethane foam prepared by using the flame retardant has excellent flame retardant property, and keeps the compression modulus and thermal insulation property of the polyurethane foam at the same time. Therefore, the polyurethane foam prepared from the flame retardant can be applied to the technical fields with flame retardant requirements, such as building insulation or support filling.

Description

Technical Field

[0001] The invention relates to the technical field of flame retardants, and in particular to a halogen-free supramolecular flame retardant for polyurethane foam and a preparation method thereof. Background Art

[0002] As of 2020, polyurethane foam accounts for 50% of the total polyurethane material used. Because of its huge surface area, 90% of its volume is composed of air or carbon dioxide, so it is easy to burn under heat sources with molten droplets, toxic smoke release and large amounts of heat release. Compared with other materials, polyurethane rigid foam has excellent thermal insulation properties and is widely used in thermal insulation materials. Polyurethane soft foam has extremely high resilience and is widely used in home textiles, elastic materials for filling, etc.

[0003] However, the flame retardant properties of these two polyurethane foams are extremely poor, with a limiting oxygen index of only 17 to 19%, and there are often safety hazards when they are used. Therefore, the existing technology has limitations. Summary of the invention

[0004] The present invention is made to solve the above problems, and aims to provide a halogen-free supramolecular flame retardant for polyurethane foam and a preparation method thereof.

[0005] The present invention provides a halogen-free supramolecular flame retardant for polyurethane foam, which has the following characteristics: the flame retardant is a compound with a primary amino terminal group formed by a solvent condensation reaction of a polyamine and a dichlorophosphonyl substance, and the chemical structure of the flame retardant is as follows:

[0006]

[0007] Among them, R1 is one of ethyl, propyl, butyl, p-xylene diamine, diethyleneamine, or triethylenediamine, R2 is one of methyl, 1,2,3-propyl, phenyl, or 1,3,5-triazine, R3 is one of methyl, phenyl, or phenoxy, and the wavy line represents a repeating structure.

[0008] The halogen-free supramolecular flame retardant for polyurethane foam provided by the present invention can also have the following characteristics: the polyamine is a liquefied polyamine, which can be one or more of ethylenediamine, propylenediamine, butylenediamine, p-phenylenediamine, 1,2,3-propylenetriamine, diethylenetriamine, triethylenetetramine, and melamine.

[0009] The halogen-free supramolecular flame retardant for polyurethane foam provided by the present invention can also have the following characteristics: the dichlorophosphonyl substance is a liquid dichlorophosphonyl substance, which can be one or more of methylphosphonyl dichloride, phenylphosphonyl dichloride, and phenoxyphosphonyl.

[0010] The halogen-free supramolecular flame retardant for polyurethane foam provided by the present invention can also have the following characteristics: the solvent is N,N-dimethyl sulfoxide (DMSO), N,N-dimethylacetamide (DMAc), or N,N-dimethylformamide (DMF).

[0011] The present invention also provides a method for preparing a halogen-free supramolecular flame retardant for polyurethane foam, which has the following characteristics: the halogen-free supramolecular flame retardant for polyurethane foam applicable to any one of the above items comprises the following steps:

[0012] S1. dissolving polyamine and chlorophosphonyl substances in solvents respectively;

[0013] S2, adjusting the temperature of a solvent containing a dichlorophosphonyl substance to 150-180° C., adding another solvent containing a polyamine dropwise into the above solvent during the heating process, and then using a magnetic stirring solution to make the reaction proceed evenly;

[0014] S3, maintaining the condensation reaction for 8 to 12 hours, and forming a yellow, dark yellow or brownish yellow insoluble crude product after the condensation reaction;

[0015] S4. The crude insoluble matter is washed with a large amount of ethanol, acetone or ether, and then dried. After drying, the crude insoluble matter is crushed with a ball mill to a mesh size of 200 to 500 to obtain a pure flame retardant.

[0016] Furthermore, in step S1, the volume ratio of the solvent to the polyamine and the chlorophosphonic acid substance is 10:1 to 20:1.

[0017] Furthermore, in step S3, the total molar ratio of chlorine atoms to amino groups in the crude insoluble matter is 1:1.1 to 1:1.3.

[0018] When the flame retardant of the present invention is used to prepare polyurethane foam, the flame retardant of the present invention is added to the isocyanate precursor before preparing the foam, and then the polyether precursor of the same mass or volume as the isocyanate precursor is added and mixed for foaming to obtain a polyurethane foam with good flame retardancy. The amount of the flame retardant added in the present invention is 10% to 30% of the mass fraction of the isocyanate precursor.

[0019] Functions and Effects of the Invention

[0020] According to the halogen-free supramolecular flame retardant for polyurethane foam involved in the present invention, due to the hydrogen bonding effect formed by the cross-linked supramolecular phosphorus-nitrogen polymer and the polyurethane, there is a close combination, and the flame retardant element is introduced into the polyurethane molecular condensed phase through blending, achieving the dual effects of condensed phase flame retardancy and gas phase flame retardancy. During use, the decline in flame retardant function caused by the migration and precipitation of flame retardants is reduced, and the flame retardant effect is long-lasting. Among them, phosphorus element has excellent flame retardant properties, and does not release hydrogen halide gas during combustion, and belongs to a class of environmentally friendly flame retardant elements. Therefore, the polyurethane foam prepared using the flame retardant of the present invention has excellent flame retardant properties, while maintaining the compression modulus and thermal insulation properties of the polyurethane foam. Therefore, the polyurethane foam prepared using the flame retardant of the present invention can be applied to technical fields with flame retardant requirements such as building insulation, support filling, vehicle insulation board, sound insulation material, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is the infrared spectrum of the halogen-free supramolecular flame retardant in the present invention. DETAILED DESCRIPTION

[0022] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is specifically described in the following embodiments in conjunction with the accompanying drawings.

[0023] Example 1

[0024] This embodiment 1 provides a halogen-free supramolecular flame retardant for polyurethane foam, which is a compound with a primary amino end group formed by a solvent condensation reaction of a polyamine and a dichlorophosphonyl substance. The chemical structure of the flame retardant is as follows:

[0025]

[0026] Among them, R1 is one of ethyl, propyl, butyl, p-xylene diamine, diethyleneamine, or triethylenediamine, R2 is one of methyl, 1,2,3-propyl, phenyl, or 1,3,5-triazine, R3 is one of methyl, phenyl, or phenoxy, and the wavy line represents a repeating structure.

[0027] In this embodiment 1, the polyamine is a liquefied polyamine, which can be one or more of ethylenediamine, propylenediamine, butylenediamine, p-phenylenediamine, 1,2,3-propylenetriamine, diethylenetriamine, triethylenetetramine, and melamine.

[0028] In this embodiment 1, the dichlorophosphonyl substance is a liquid dichlorophosphonyl substance, which can be one or more of methylphosphonyl dichloride, phenylphosphonyl dichloride, and phenoxyphosphonyl.

[0029] In this embodiment 1, the solvent is N,N-dimethyl sulfoxide (DMSO), N,N-dimethylacetamide (DMAc), or N,N-dimethylformamide (DMF).

[0030] This embodiment 1 also provides a method for preparing a halogen-free supramolecular flame retardant for polyurethane foam, which is applicable to the above-mentioned halogen-free supramolecular flame retardant for polyurethane foam, and comprises the following steps:

[0031] S1. dissolving polyamine and chlorophosphonyl substances in solvents respectively;

[0032] S2, adjusting the temperature of a solvent containing a dichlorophosphonyl substance to 150-180° C., adding another solvent containing a polyamine dropwise into the above solvent during the heating process, and then using a magnetic stirring solution to make the reaction proceed evenly;

[0033] S3, maintaining the condensation reaction for 8 to 12 hours, and forming a yellow, dark yellow or brownish yellow insoluble crude product after the condensation reaction;

[0034] S4. The crude insoluble matter is washed with a large amount of ethanol, acetone or ether, and then dried. After drying, the crude insoluble matter is crushed with a ball mill to a mesh size of 200 to 500 to obtain a pure flame retardant.

[0035] Furthermore, in step S1, the volume ratio of the solvent to the polyamine and the chlorophosphonic acid substance is 10:1 to 20:1.

[0036] Furthermore, in step S3, the total molar ratio of chlorine atoms to amino groups in the crude insoluble matter is 1:1.1 to 1:1.3.

[0037] In this embodiment 1, the specific preparation process of the cross-linked supramolecular phosphorus-nitrogen polymer added flame retardant of the present invention is as follows:

[0038] First, 3-3.1 molar ratio of triethylenetetramine was weighed and poured into a flask connected to a reflux device and stirred, and 2 molar ratio of phenylphosphoryl dichloride was slowly added dropwise to produce a red solid powder.

[0039] Next, the liquid is heated to 200-230°C to change the solid powder from red to a dark red solution, and then reacted for 3-6 hours to ensure that the reaction is complete. After cooling, the solid prepared by the reaction is taken out to obtain a cross-linked supramolecular phosphorus-nitrogen polymer added flame retardant.

[0040] Finally, the cross-linked supramolecular phosphorus-nitrogen polymer added flame retardant obtained above is crushed by a crusher and the flame retardant with a mesh size below 200 is screened out for preparing polyurethane foam.

[0041] The preparation process of flame retardant polyurethane foam using the flame retardant prepared in Example 1 is as follows:

[0042] Take 0.5-1.5 parts by weight of cross-linked supramolecular phosphorus-nitrogen polymer added flame retardant into 10 parts by weight of isocyanate precursor, then mix the isocyanate precursor with 10 parts by weight of polyether precursor, stir and react to foam, and then keep warm at 50-90°C for 10-60 minutes to obtain flame-retardant polyurethane foam.

[0043] Example 2

[0044] The difference between Example 2 and Example 1 is that a specific preparation process for preparing the flame retardant of the present invention is further provided, which is applicable to the above-mentioned halogen-free supramolecular flame retardant for polyurethane foam. The preparation process is as follows:

[0045] First, 1-1.1 molar ratio of diaminobutane is weighed and poured into a flask connected to a reflux device and stirred, and 1 molar ratio of phenylphosphoryl dichloride is slowly added dropwise to produce a red solid powder.

[0046] Next, the liquid is heated to 220-240°C to change the solid powder from red to a dark red solution, and then reacted for 3-6 hours to ensure that the reaction is complete. After cooling, the solid prepared by the reaction is taken out to obtain a linear macromolecular phosphorus-nitrogen polymer added flame retardant.

[0047] Finally, the linear macromolecular phosphorus-nitrogen polymer added flame retardant obtained in the above process is crushed by a crusher and the flame retardant with a mesh size below 200 is screened out for preparing polyurethane foam.

[0048] The preparation process of flame retardant polyurethane foam prepared by using the flame retardant prepared in Example 2 is as follows:

[0049] Take 0.5-1.5 parts by weight of linear macromolecular phosphorus-nitrogen polymer added flame retardant into 10 parts by weight of isocyanate precursor, then mix the isocyanate precursor with 10 parts by weight of polyether precursor, stir and react to foam, and then keep warm at 50-90°C for 10-60 minutes to obtain flame-retardant polyurethane foam.

[0050] Apart from this, the other contents of Example 2 are the same as those of Example 1.

[0051] Example 3

[0052] The difference between Example 3 and Example 1 is that a specific preparation process for preparing the flame retardant of the present invention is further provided, which is applicable to the above-mentioned halogen-free supramolecular flame retardant for polyurethane foam. The preparation process is as follows:

[0053] First, 1-1.1 molar ratio of ethylenediamine is weighed and poured into a flask connected to a reflux device and stirred, and 1 molar ratio of phenylphosphoryl dichloride is slowly added dropwise to produce a red solid powder.

[0054] Next, the liquid is heated to 260-300°C to change the solid powder from red to a dark red solution, and then reacted for 3-6 hours to ensure that the reaction is complete. After cooling, the solid prepared by the reaction is taken out to obtain a linear macromolecular phosphorus-nitrogen polymer added flame retardant.

[0055] Finally, the linear macromolecular phosphorus-nitrogen polymer added flame retardant obtained in the above process is crushed by a crusher and the particles with a size of less than 200 meshes are selected for preparing foam.

[0056] The preparation process of flame retardant polyurethane foam using the flame retardant prepared in Example 3 is as follows:

[0057] Take 0.5-1.5 parts by weight of linear macromolecular phosphorus-nitrogen polymer added flame retardant into 10 parts by weight of isocyanate precursor, then mix the isocyanate precursor with 10 parts by weight of polyether precursor, stir and react to foam, and then keep warm at 50-90°C for 10-60 minutes to obtain flame-retardant polyurethane foam.

[0058] Apart from this, the other contents of Example 3 are the same as those of Example 1.

[0059] Comparative experiment

[0060] The present invention compares the flame retardants obtained in Example 1, Example 2 and Example 3, and the polyurethane foam prepared by the flame retardants through three aspects: limiting oxygen index evaluation, thermal constant analysis, and compression performance test, as shown below.

[0061] Example 1

[0062] 6.6 g of phenylphosphoryl dichloride was poured into a three-necked flask equipped with a spherical condenser and 7.3 g of triethylenetetramine was placed in a constant pressure funnel and slowly added dropwise into the three-necked flask, and the temperature was raised to 230°C to react until a dark red solid was obtained to obtain a cross-linked supramolecular phosphorus-nitrogen polymer added flame retardant. Then, the cross-linked supramolecular phosphorus-nitrogen polymer added flame retardant was crushed using a pulverizer and 200 mesh particles were screened out and then an isocyanate precursor was added.

[0063] 1 g of cross-linked supramolecular phosphorus-nitrogen polymer added flame retardant was added to 10 g of isocyanate precursor and stirred for pre-reaction, and then the two precursors were mixed and foamed. After the foaming was sufficient, the mixture was kept at 60° C. for 10 minutes to obtain a foam sample.

[0064] Sample performance

[0065]

[0066]

[0067] Example 2

[0068] 6.6g of phenylphosphoryl dichloride was poured into a three-necked flask equipped with a spherical condenser and 3g of diaminodiamine was placed in a constant pressure funnel and slowly added dropwise into the three-necked flask, and the temperature was raised to 230°C to react until a dark red solid was obtained to obtain a linear macromolecular phosphorus nitrogen polymer added flame retardant. Then the linear macromolecular phosphorus nitrogen polymer added flame retardant was crushed using a pulverizer, and 200 mesh particles were screened out and then an isocyanate precursor was added.

[0069] Take 1g of linear macromolecular phosphorus-nitrogen polymer added flame retardant and add 10g of isocyanate precursor to stir for pre-reaction, then mix the two precursors for foaming, and keep warm at 60°C for 10 minutes after sufficient foaming to obtain a foam sample.

[0070] Sample performance

[0071]

[0072] Example 3

[0073] 6.6 g of phenylphosphoryl dichloride was poured into a three-necked flask equipped with a spherical condenser and 4.1 g of ethylenediamine was placed in a constant pressure funnel and slowly added dropwise into the three-necked flask, and the temperature was raised to 250°C to react until a dark red solid was obtained to obtain a linear macromolecular phosphorus nitrogen polymer added flame retardant. Then, the linear macromolecular phosphorus nitrogen polymer added flame retardant was crushed using a pulverizer, and 200 mesh particles were screened out and subsequently added to the isocyanate precursor.

[0074] Take 1g of linear macromolecular phosphorus-nitrogen polymer added flame retardant and add 10g of isocyanate precursor to stir for pre-reaction, then mix the two precursors for foaming, and keep warm at 60°C for 10 minutes after sufficient foaming to obtain a foam sample.

[0075] Sample performance

[0076]

[0077] Functions and Effects of the Embodiments

[0078] According to the halogen-free supramolecular flame retardant for polyurethane foam involved in the present invention, due to the hydrogen bonding effect formed by the cross-linked supramolecular phosphorus-nitrogen polymer and the polyurethane, there is a close combination, and the flame retardant element is introduced into the polyurethane molecular condensed phase through blending, achieving the dual effects of condensed phase flame retardancy and gas phase flame retardancy. During use, the decline in flame retardant function caused by the migration and precipitation of flame retardants is reduced, and the flame retardant effect is long-lasting. Among them, phosphorus element has excellent flame retardant properties, and does not release hydrogen halide gas during combustion, and belongs to a class of environmentally friendly flame retardant elements. Therefore, the polyurethane foam prepared using the flame retardant of the present invention has excellent flame retardant properties, while maintaining the compression modulus and thermal insulation properties of the polyurethane foam. Therefore, the polyurethane foam prepared using the flame retardant of the present invention can be applied to technical fields with flame retardant requirements such as building insulation, support filling, vehicle insulation board, sound insulation material, etc.

[0079] According to the halogen-free supramolecular flame retardant for polyurethane foam involved in the present invention, the polyurethane foam prepared by using the flame retardant of the present invention can increase the oxygen index of the foam to about 25%, and the supramolecular structure of the flame retardant of the present invention can prevent it from seeping into the environment, which can greatly increase the application scenarios of the polyurethane foam.

[0080] The above-mentioned embodiments are preferred examples of the present invention and are not intended to limit the protection scope of the present invention.

Claims

1. A halogen-free supramolecular flame retardant for polyurethane foam, characterized in that: The flame retardant is a compound with a primary amino terminal group formed by a solvent condensation reaction of a polyamine and a dichlorophosphonic acid substance. The chemical structure of the flame retardant is as follows: Among them, R1 is one of ethyl, propyl, butyl, p-phenylenediamine, diethyleneamino, or triethylenediamine, R2 is one of methyl, 1,2,3-propyl, phenyl, or 1,3,5-triazine, and R3 is one of methyl, phenyl, or phenoxy.

2. The halogen-free supramolecular flame retardant for polyurethane foam according to claim 1, characterized in that: in, The polyamine is a liquefied polyamine, which may be one or more of ethylenediamine, propylenediamine, butylenediamine, p-phenylenediamine, 1,2,3-propylenetriamine, diethylenetriamine, triethylenetetramine, and melamine.

3. The halogen-free supramolecular flame retardant for polyurethane foam according to claim 1, characterized in that: in, The dichlorophosphonyl substance is a liquid dichlorophosphonyl substance, which can be one or more of methylphosphonyl dichloride, phenylphosphonyl dichloride, and phenoxyphosphonyl.

4. The halogen-free supramolecular flame retardant for polyurethane foam according to claim 1, characterized in that: in, The solvent is N,N-dimethyl sulfoxide (DMSO), N,N-dimethylacetamide (DMAc), or N,N-dimethylformamide (DMF).

5. A method for preparing a halogen-free supramolecular flame retardant for polyurethane foam, characterized in that: The flame retardant according to any one of claims 1 to 4 comprises the following steps: S1, dissolving the polyamine and the chlorophosphonyl substance in the solvent respectively; S2, adjusting the temperature of a solvent containing the dichlorophosphonyl substance to 150-180° C., adding another solvent containing the polyamine dropwise into the above solvent during the heating process, and then stirring the solution with a magnetic force to make the reaction proceed evenly; S3, maintaining the condensation reaction for 8 to 12 hours, and forming a yellow, dark yellow or brownish yellow insoluble crude product after the condensation reaction; S4. The crude insoluble matter is washed with a large amount of ethanol, acetone or ether, dried after washing, and crushed with a ball mill to a mesh size of 200 to 500 to obtain a pure flame retardant.

6. The method for preparing the halogen-free supramolecular flame retardant for polyurethane foam according to claim 5, characterized in that: In step S1, the volume ratio of the solvent to the polyamine and the chlorophosphonate substance is 10:1 to 20:

1.

7. The method for preparing the halogen-free supramolecular flame retardant for polyurethane foam according to claim 5, characterized in that: In step S3, the total molar ratio of chlorine atoms to amino groups in the crude insoluble matter is 1:1.1 to 1:1.3.

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