A multifunctional phosphate polyol flame retardant, a low-viscosity multifunctional phosphate flame retardant, a preparation method thereof, and applications thereof

Abstract

The present invention provides a multifunctional phosphate polyol flame retardant, a low-viscosity multifunctional phosphate flame retardant, a preparation method thereof and an application thereof, which solve the technical problem that the existing flame retardants cannot meet the demand of the polyurethane foam industrial system for multifunctional flame retardant products; wherein the multifunctional phosphate polyol flame retardant has a structure shown in the following formula (I): #imgabs0# Formula (I); wherein R1~R 10 H or #imgabs1# alone, and R1~R 10 At least one of them is not an H structure; m=1; the low-viscosity multifunctional phosphate flame retardant has a structure shown in the following formula (II): #imgabs2# Formula (II); wherein R1~R 10 H or #imgabs3# alone, and R1~R 10 At least one is not an H structure; m=1; R is #imgabs4# or #imgabs5#, and n is a positive integer; at the same time, the application also provides a preparation method and application of the above-mentioned multifunctional phosphate polyol flame retardant and low-viscosity multifunctional phosphate flame retardant, which can be widely used in the field of polymer flame retardant material technology.

Description

Technical Field

[0001] The present application relates to the technical field of polymer flame retardant materials, and in particular to a multifunctional phosphate polyol flame retardant, a low-viscosity multifunctional phosphate flame retardant, a preparation method thereof, and applications thereof. Background Art

[0002] Rigid polyurethane foam is a foam with high polarity, high cross-linking degree, low density and closed-cell network structure. In recent years, due to the excellent performance of rigid polyurethane foam, its production growth rate is very alarming. However, due to the porous and flammable characteristics of polyurethane foam, polyurethane rigid foam currently used in the fields of construction, transportation, etc., needs to add flame retardants to improve the fire resistance of the products to meet the national requirements and standards for flame retardancy. There are two main forms of commonly used flame retardants: one is an additive flame retardant, which is added to polyurethane by physical blending. The solubility of this flame retardant and polymer polyol directly affects its flame retardant effect, and the flame retardant is usually added in large amounts, easy to migrate, and precipitate to the surface of polyurethane foam, affecting the physical properties of polyurethane foam; the other is a reactive flame retardant, which enters the polymer molecular chain as a unit chemical bond during the polyurethane synthesis process. This is a flame retardant polyether polyol with a stable structure.

[0003] Phenolic polyether polyols prepared by Mannich reaction are a very important type of polyol products in the polyurethane industry and are widely used in the field of rigid polyurethane foam. Compared with ordinary rigid foam polyether polyols, the introduction of benzene rings gives the product an aromatic ring structure, excellent heat resistance, flame retardancy and mechanical properties, good compatibility with polymerized MDI and its own self-catalytic activity, and less or even no catalyst can be used in the foaming formula. However, due to the particularity of the physical and chemical properties of this polyether polyol, its application in the field of non-spraying rigid polyurethane foam is very rare. In addition, this polyether polyol tends to become a solid powder or a high-viscosity liquid, and is not suitable for applications in the fields of pipelines, boxes, etc. Therefore, a new low-viscosity flame retardant with excellent physical properties is needed to meet the demand for multifunctional flame retardant products in the existing polyurethane foam industry system. Summary of the invention

[0004] The purpose of the present invention is to solve the deficiencies of the above-mentioned technologies and provide a multifunctional phosphate polyol flame retardant, a low-viscosity multifunctional phosphate flame retardant, a preparation method thereof and an application thereof, so as to meet the demand of the polyurethane foam industrial system for multifunctional flame retardant products.

[0005] To this end, the present invention provides a multifunctional phosphate polyol flame retardant having a structure shown in the following formula (I):

[0006]

[0007] Formula (I);

[0008] Among them, R1~R 10 H alone or , and R1~R 10 At least one is not an H structure; m=1.

[0009] The preparation method of the multifunctional phosphate polyol flame retardant comprises the following preparation steps:

[0010] The formaldehyde substance and diethanolamine are reacted to obtain a reaction intermediate with a hydroxyl structure; the reaction intermediate and resorcinol tetraphenyl diphosphate (RDP) are subjected to a Mannich reaction to obtain the multifunctional phosphate polyol flame retardant.

[0011] Preferably, the formaldehyde substance is reacted with diethanolamine at a temperature of 80-100°C. After the reaction, the temperature is maintained at 80-100°C, and unreacted formaldehyde substances are removed by reduced pressure distillation to obtain the reaction intermediate; the reaction intermediate and resorcinol tetraphenyl diphosphate are subjected to a Mannich reaction at a temperature of 80-100°C. After the reaction, a crude multifunctional phosphate polyol flame retardant is obtained, and after post-treatment, a refined multifunctional phosphate polyol flame retardant is obtained.

[0012] Preferably, the post-treatment method comprises: dissolving the crude multifunctional phosphate polyol flame retardant in an organic solvent, adding an appropriate amount of pure water, stirring at 30-50°C, washing multiple times, standing for stratification, removing the upper clear liquid, taking the lower liquid and removing the organic solvent by distillation to obtain the refined multifunctional phosphate polyol flame retardant. Preferably, the formaldehyde substance is one of formaldehyde, trioxymethylene and polyformaldehyde.

[0013] Preferably, the organic solvent is one of dichloromethane, dichloroethane, carbon tetrachloride and N,N-dimethylformamide.

[0014] A low-viscosity multifunctional phosphate flame retardant having a structure shown in the following formula (II):

[0015]

[0016] Formula (II);

[0017] Among them, R1~R 10 H alone or , and R1~R 10 At least one is not an H structure; m=1;

[0018] R is or , n is a positive integer.

[0019] Preferably, the viscosity of the low-viscosity multifunctional phosphate flame retardant at 25° C. is less than 6000 mPa•s.

[0020] The preparation method of the low-viscosity multifunctional phosphate flame retardant comprises the following preparation steps:

[0021] Under the action of a catalyst, tert-butyl acetoacetate (TBAA) is reacted with the multifunctional phosphate polyol flame retardant to obtain the low-viscosity multifunctional phosphate flame retardant.

[0022] Preferably, the catalyst is one of potassium hydroxide, sodium hydroxide, potassium carbonate and potassium bicarbonate.

[0023] Preferably, epichlorohydrin is reacted with the multifunctional phosphate polyol flame retardant under a nitrogen or inert gas environment to obtain the low-viscosity multifunctional phosphate flame retardant.

[0024] Preferably, when the reactant is tert-butyl acetoacetate, tert-butyl acetoacetate and the multifunctional phosphate polyol flame retardant are reacted at a temperature of 90-120° C. under the action of potassium hydroxide as a catalyst. After the reaction is completed, the generated tert-butyl alcohol is removed by distillation to obtain the low-viscosity multifunctional phosphate flame retardant.

[0025] When the reactant is epichlorohydrin, epichlorohydrin is reacted with the multifunctional phosphate polyol flame retardant at 90-120° C. in a nitrogen or inert gas environment. After the reaction is completed, unreacted epichlorohydrin is removed by reduced pressure distillation to obtain the low-viscosity multifunctional phosphate flame retardant.

[0026] The low-viscosity multifunctional phosphate flame retardant is applied to the flame-retardant polyurethane foaming composition.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The low-viscosity multifunctional phosphate flame retardant of the present invention has a phosphorus-oxygen double bond, a hydroxyl group, a β-dicarbonyl group and a halogen structure. As a reactive flame retardant, the active methylene group between the β-dicarbonyl structure can react with isocyanate groups, amine groups, unsaturated double bonds, aldehyde groups, etc., and can therefore be compounded with general polyether polyols for polyurethane foaming. The presence of phosphorus can effectively improve the flame retardant properties of polyurethane foam products; and the presence of a halogen structure can further improve the flame retardant properties of polyurethane foam; the hydroxyl structure can accelerate the polyurethane foaming process and reduce the surface drying and actual drying time of the foaming; more importantly, the low viscosity characteristic makes it easy to mix with other materials according to the formula. Therefore, the low-viscosity multifunctional phosphate flame retardant of the present invention can be used as an excellent and efficient flame retardant for polyurethane foaming.

[0029] (2) The preparation method of the present invention uses formaldehyde, diethanolamine and resorcinol tetraphenyl diphosphate (RDP) as raw materials to synthesize a multifunctional phosphate ester polyol flame retardant. The multifunctional phosphate ester polyol flame retardant is subjected to an esterification reaction with tert-butyl acetoacetate (TBAA) or an addition reaction between the multifunctional phosphate ester polyol flame retardant and epichlorohydrin (ECH) to synthesize a low-viscosity multifunctional phosphate ester flame retardant.

[0030] (3) The flame retardant product of the present invention can be used as a reactive flame retardant and can be compounded with common polyether polyols to prepare polyurethane foam products. The prepared polyurethane foam products will not have problems such as flame retardant migration and precipitation to the surface, thereby achieving the flame retardant goal while improving the physical properties of the polyurethane foam. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application.

[0032] Figure 1 This is the infrared spectrum of the multifunctional phosphate polyol flame retardant prepared in Example 1;

[0033] Figure 2 This is the infrared spectrum of the low-viscosity multifunctional phosphate flame retardant prepared in Example 2;

[0034] Figure 3 This is the infrared spectrum of the low-viscosity multifunctional phosphate flame retardant prepared in Example 3. DETAILED DESCRIPTION

[0035] In order to explain the present invention more clearly, the present invention is further described below in conjunction with preferred embodiments. It should be understood by those skilled in the art that the following specific description is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

[0036] Unless otherwise specified, the methods used in the present invention are all conventional methods; the raw materials and devices used are all conventional commercially available products unless otherwise specified.

[0037] Resorcinol tetraphenyl diphosphate (RDP) was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.;

[0038] Diethanolamine was purchased from Tianjin Yongda Chemical Reagent Co., Ltd.;

[0039] Paraformaldehyde was purchased from Tianjin Yongda Chemical Reagent Co., Ltd.;

[0040] Tert-butyl acetoacetate (TBAA) was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.;

[0041] Epichlorohydrin (ECH) was purchased from Changzhou Dejin Chemical Co., Ltd.;

[0042] Dichloromethane was purchased from Shandong Jinling Chemical Co., Ltd.;

[0043] The viscometer model is NDJ-8S, 4# rotor, purchased from Shanghai Lichen Bangxi Instrument Technology Co., Ltd.

[0044] Example 1

[0045] This embodiment provides a method for synthesizing a multifunctional phosphate polyol flame retardant, comprising the following preparation steps:

[0046] Weigh 57.75 g of diethanolamine and add it to a four-necked flask. Install a reflux condenser and a thermometer, heat to 63 ° C, add 15 g of paraformaldehyde in batches, and stir until the paraformaldehyde is completely dissolved. Heat up and control the temperature at 80-100 ° C, react for 2.5 h, and then remove the unreacted paraformaldehyde by reduced pressure distillation to obtain a reaction intermediate. Then cool to room temperature, add 287 g of resorcinol tetraphenyl diphosphate (RDP), heat again, control the temperature at 80-100 ° C, react for 4 h, and obtain a crude multifunctional phosphate polyol flame retardant. The crude multifunctional phosphate polyol flame retardant is dissolved in dichloromethane, and pure water of the same mass is added. Stir and wash for 0.5 h at a temperature of 30-50 ° C, let stand for stratification, take the lower layer of liquid and continue to add pure water to repeat the washing for 3-5 times, and then remove the solvent dichloromethane by distillation to obtain a refined multifunctional phosphate polyol flame retardant.

[0047] The viscosity of the multifunctional phosphate polyol flame retardant was 14400 mPa•s (25°C) after viscometer testing. The experimental test found that its hydroxyl value was 173.6 mg KOH / g.

[0048] In order to further confirm the synthesis of the multifunctional phosphate polyol flame retardant, the multifunctional phosphate polyol flame retardant prepared in Example 1 was characterized by infrared spectroscopy. Figure 1 As shown. Figure 1 It can be found that at 3064cm -1 The peak at 1640 cm is the stretching vibration peak of aromatic hydrocarbon =CH; -1 、1591 cm -1 and 1487 cm -1 The absorption peaks at 1297 cm -1The peak at 1193 cm is the stretching vibration peak of the P=O bond in aryl phosphate (ArO) 3P=O; -1 、947 cm -1 and 915 cm -1 The peak at 3309 cm-1 corresponds to the stretching vibration peak of the POC bond in PO-Ar, proving the main structure of aromatic phosphate (RDP); -1 The broad band at 1089 cm is the stretching vibration peak of OH, proving the successful introduction of alcoholic hydroxyl groups; -1 The peak at is the stretching vibration peak of the CN bond in the following structural formula A. Combining the structural formula of diethanolamine, the combination of the OH structure and the following structural formula A can prove the existence of the following structural formula B, which further indicates that the multifunctional phosphate polyol flame retardant structure described in formula (I) of the present invention has been successfully synthesized.

[0049] Structural formula A is: ;

[0050] Structural formula B is: .

[0051] Example 2

[0052] This embodiment provides a method for preparing a low-viscosity multifunctional phosphate flame retardant, comprising the following preparation steps:

[0053] 55.2 g of the refined multifunctional phosphate polyol flame retardant prepared by the method described in Example 1 and 7.1 g of tert-butyl acetoacetate (TBAA) were weighed and added into a three-necked flask, and then 0.24 g of KOH was added as a catalyst. The mixture was heated and the temperature was controlled at 90-120° C. and reacted at normal pressure for 3 h. Thereafter, water and tert-butyl alcohol generated by the reaction were removed by distillation to obtain a low-viscosity multifunctional phosphate flame retardant.

[0054] After viscometer testing, the viscosity of the prepared low-viscosity multifunctional phosphate flame retardant was 2350 mPa•s (25°C), which is below 6000 mPa•s.

[0055] In order to further confirm the synthesis of the low-viscosity multifunctional phosphate flame retardant, the low-viscosity multifunctional phosphate flame retardant prepared in Example 2 was characterized by infrared spectroscopy. Figure 2 As shown. Figure 2 It can be found that at 1596cm -1 and 1476 cm -1 The absorption peaks at 1302 cm -1 The peak at 1182 cm is the stretching vibration peak of the P=O bond in aryl phosphate (ArO) 3P=O; -1 、942 cm -1and 910 cm -1 The peak at 1089 cm corresponds to the stretching vibration peak of the POC bond in PO-Ar; -1 The peak at 2966 cm is the stretching vibration peak of the CN bond in the following structural formula A; compared with the infrared spectrum of the multifunctional phosphate polyol flame retardant prepared in Example 1, -1 A new infrared absorption peak appears at 1744 cm -1 、1716 cm -1 and 1662 cm -1 The infrared absorption peaks at are the stretching vibration absorption peaks of ester-OC=O and ketocarbonyl-C=O. Combining the structural formula of tert-butyl acetoacetate (TBAA), the -C-CH2-C- structure, the ester-OC=O structure and the ketocarbonyl-C=O structure can prove the existence of the β-ketoester structure, i.e., the following structural formula C. The combination of the following structural formula A and the following structural formula C can prove that the low-viscosity multifunctional phosphate flame retardant structure described in formula (II) of the present invention has been successfully synthesized.

[0056] Structural formula A is: ;

[0057] Structural formula C is: .

[0058] Example 3

[0059] This embodiment provides a method for preparing a low-viscosity multifunctional phosphate flame retardant, comprising the following preparation steps:

[0060] 69 g of the refined multifunctional phosphate polyol flame retardant prepared by the method described in Example 1 and 55.5 g of epichlorohydrin (ECH) were weighed and added into a four-necked flask, and N2 was introduced. The temperature was raised and controlled at 90-120°C. The reaction was carried out at normal pressure for 3 h under N2 atmosphere, and then the unreacted epichlorohydrin was removed by reduced pressure distillation to obtain a low-viscosity multifunctional phosphate flame retardant.

[0061] After viscometer testing, the viscosity of the prepared low-viscosity multifunctional phosphate flame retardant was 5300 mPa•s (25°C), which is below 6000 mPa•s.

[0062] In order to further confirm the synthesis of the low-viscosity multifunctional phosphate flame retardant, the low-viscosity multifunctional phosphate flame retardant prepared in Example 3 was characterized by infrared spectroscopy. Figure 3 As shown. Figure 3 It can be found that at 3314cm -1 The broad band at 1593 cm is the stretching vibration peak of OH, proving the existence of C-OH structure;-1 and 1486 cm -1 The absorption peaks at 1292 cm -1 The peak at 1185 cm is the stretching vibration peak of the P=O bond in aryl phosphate (ArO) 3P=O; -1 、954 cm -1 The peak at 1082 cm corresponds to the stretching vibration peak of the POC bond in PO-Ar; -1 The peak at 1228 cm is the stretching vibration peak of the CN bond in the following structural formula A; compared with the infrared spectrum of the multifunctional phosphate polyol flame retardant prepared in Example 1, -1 A new infrared absorption peak appears at 835 cm, which is the asymmetric stretching vibration peak of the CO bond in the ether bond COC structure, proving the existence of the -CH2-O-CH2- structure; -1 The infrared absorption peak at is the stretching vibration absorption peak of C-Cl, proving the existence of -CH2-Cl structure; combined with the structural formula of epichlorohydrin (ECH), the infrared absorption peaks of -CH2-O-CH2- structure, -CH2-Cl and C-OH structure can prove the existence of the following structural formula D, the following structural formula A and the following structural formula D, which can prove that the low-viscosity multifunctional phosphate flame retardant structure described in formula (II) of the present invention has been successfully synthesized.

[0063] Structural formula A is: ;

[0064] The structural formula D is: .

[0065] Example 4

[0066] This embodiment provides a method for preparing a low-viscosity multifunctional phosphate flame retardant, comprising the following preparation steps:

[0067] Repeat Examples 1-3, using other formaldehyde substances such as formaldehyde and trioxymethylene instead of polyformaldehyde, other organic solvents such as dichloroethane, carbon tetrachloride, N,N-dimethylformamide instead of dichloromethane, other catalysts such as sodium hydroxide, potassium carbonate, potassium bicarbonate instead of potassium hydroxide, and other steps are the same. The obtained low-viscosity multifunctional phosphate flame retardant exhibits similar effects to Examples 1-3, which are not repeated here.

[0068] Polyurethane foam formula calculation:

[0069] The molecular structure of rigid polyurethane foam consists of soft segments and hard segments. The soft segment structure comes from polyols, and the hard segment structure comes from polyisocyanates. The reaction of isocyanate groups (-NCO) and hydroxyl groups (-OH), amino groups (-NH2) and water generates carbamate bonds (-NHCOO-), urea bonds (-HNCONH-) and carbamic acid, respectively. Carbamic acid is very unstable and will immediately decompose into amino groups and carbon dioxide. This is also the reaction principle of chemical foaming agents.

[0070] During the polyurethane foaming process, the active functional groups in the reactive flame retardant react chemically with the polyurethane and are bonded to the polyurethane macromolecular chain in the form of chemical bonds, introducing flame retardant elements or groups or generating covalent bonds with higher bond energy, thereby improving the flame retardant properties of the polyurethane.

[0071] 1. Calculation of polyisocyanate and polyol dosage:

[0072] (1) Equivalent weight (E) = relative molecular mass (M) / functionality (f).

[0073] (2) Hydroxyl value of polyol or hydroxy compound: refers to the number of milligrams of potassium hydroxide equivalent to the hydroxyl content in 1g of polyol or hydroxy compound (mgKOH / g) = 56.1×1000 / polyol equivalent.

[0074] (3) Polyisocyanate equivalent

[0075] Polyisocyanate equivalent = 42.02 × 100% / mass fraction of polyisocyanate groups.

[0076] (4) Polyisocyanate requirement

[0077] Polyisocyanate required per hydroxyl substance = equivalent polyisocyanate / equivalent hydroxyl substance.

[0078] 2. Calculation of catalyst dosage: Catalyst dosage (g) = polyol dosage (kg) / mass ratio × 0.6.

[0079] 3. Calculation of foaming agent dosage: Foaming agent dosage (g) = polyol dosage (kg) / mass ratio × 5.

[0080] 4. Calculation of additive dosage: additive dosage (g) = polyol dosage (kg) / mass ratio × 3.

[0081] Here, “mass ratio” refers to the percentage of polyisocyanate in polyol.

[0082] 5. Notes on formula calculation

[0083] (1) It is best to actually measure the hydroxyl value, moisture content, acid value and other indicators of the polyol to ensure the accuracy of the calculation.

[0084] (2) The water content of other components should also be considered, especially when fillers are added.

[0085] (3) The active groups in additives, such as amine and hydroxyl groups, should also be taken into account in calculating the polyisocyanate they consume.

[0086] During use, the theoretical dosage is only a reference value. The best ratio needs to be determined by combining and examining the actual physical properties and flame retardant properties of the polyurethane after foaming.

[0087] Application Example 1

[0088] An application of the above multifunctional phosphate polyol flame retardant comprises the following preparation steps:

[0089] Turn on the balance and preheat for more than 5 minutes. Calibrate if necessary, and pad the film plastic bag in the wooden box. First, introduce the polyether polyol in the formula and the multifunctional phosphate polyol flame retardant prepared in Example 1 into a disposable plastic cup. Except for polyisocyanate (PAPI), other reagents are added into the plastic cup, stirred and mixed at a speed of 600r / min for 2 minutes, and used as white material for standby. Polyisocyanate itself is used as black material for standby. The specific amount of reagents added in the formula is shown in Table 1. Set the temperature of the thermostat to the required temperature (T=25℃), and the constant material temperature T1=T2=T (if it is a water bath thermostat, pay attention to the protection of the raw materials from water absorption) Place the disposable cup on the balance and reset it to zero; pour in the amount of white material designed in the formula and reset it to zero. Add the amount of black material designed in the formula according to the ratio coefficient. Stir the black and white material mixture slowly first (turn on the stopwatch at the same time) to avoid splashing and affecting the ratio; stir at full speed for 8-10 seconds after 2-3 seconds (try to shorten the operation time of the above two steps). Then quickly pour the stirred raw materials into a plastic cup or wooden box and allow them to foam freely. After the foaming stops, place them in a natural environment and continue to react for 24 hours.

[0090] Table 1 Flame retardant polyurethane foaming experimental formula

[0091]

[0092] Application Example 2

[0093] An application of the above-mentioned low-viscosity multifunctional phosphate flame retardant comprises the following preparation steps:

[0094] The polyether polyol in the formula and the low-viscosity multifunctional phosphate flame retardant prepared in Example 2 are introduced into a disposable plastic cup. Except for the polyisocyanate (PAPI), other reagents are introduced into the plastic cup, and stirred and mixed at a speed of 600r / min for 2 minutes, and used as white material for standby. The polyisocyanate itself is used as black material for standby. The addition amount of the flame retardant in Example 2 in the formula is the same as the addition amount of the flame retardant in Example 1, and the addition amount of the reagents and other contents are the same as those in Application Example 1, which will not be repeated here.

[0095] Application Example 3

[0096] An application of the above-mentioned low-viscosity multifunctional phosphate flame retardant comprises the following preparation steps:

[0097] The polyether polyol in the formula and the low-viscosity multifunctional phosphate flame retardant prepared in Example 3 are introduced into a disposable plastic cup. Except for the polyisocyanate (PAPI), other reagents are introduced into the plastic cup, and stirred and mixed at a speed of 600r / min for 2 minutes as a white material. The polyisocyanate itself is used as a black material. The addition amount of the flame retardant in Example 3 in the formula is the same as the addition amount of the flame retardant in Example 1, and the addition amount of the reagents and other contents are the same as those in Application Example 1, which will not be repeated here.

[0098] The standard specimens prepared for the above application examples 1-3 were used for LOI testing. .

[0099] According to the LOI foam material test standard, the standard size of the sample (length × width × thickness) should be 70-150mm × 10±0.5mm × 10±0.5mm. (Test standard: GB / T2406.3-2022 standard, determination of limiting oxygen index of foam plastics)

[0100] Test method: Use a sample clamp to clamp the standard sample vertically in a transparent combustion tube, in which there is an upward flow of oxygen and nitrogen mixed in a certain proportion. Light the upper end of the sample, observe the subsequent combustion phenomenon, and record the continuous combustion time or the distance burned. When the burning time of the sample exceeds 3 minutes or the flame front exceeds the 50 mm mark, reduce the oxygen concentration. When the burning time of the sample is less than 3 minutes or the flame front does not reach the mark, increase the oxygen concentration. Repeat this operation, gradually approaching the specified value from the upper and lower sides, until the concentration difference between the two is less than 0.5%.

[0101] The average value of all test data is the final test result. See Table 2 for the test results.

[0102] Table 2: LOI test results of application examples 1-3

[0103]

[0104] At present, the limiting oxygen index (LOI) of polyurethane foam without flame retardant treatment is generally only 14-16%. The test data in Table 2 above show that the limiting oxygen index (LOI) of the polyurethane foam test specimens (Application Examples 1-3) prepared by adding the multifunctional phosphate polyol flame retardant synthesized by the method of the present invention and the low-viscosity multifunctional phosphate flame retardant all reaches more than 24.5%, and the flame retardant performance of the polyurethane foam is greatly improved.

[0105] Application Example 4

[0106] An application of the above multifunctional phosphate polyol flame retardant comprises the following preparation steps:

[0107] Turn on the balance and preheat for more than 5 minutes. Calibrate if necessary, and place the film plastic bag in the wooden box. Introduce the polyether polyol in the formula and the flame retardant prepared in Example 1 into a disposable plastic cup. Except for polyisocyanate (PAPI), other reagents are added into the plastic cup, and stirred and mixed at a speed of 600r / min for 2 minutes as white material for standby. Polyisocyanate itself is used as black material for standby. The specific amount of reagents added in the formula is shown in Table 3. Set the temperature of the thermostat to the required temperature (T=25℃), and the constant material temperature T1=T2=T (if it is a water bath thermostat, pay attention to the protection of the raw materials from water absorption). Put the disposable cup on the balance and reset it; pour in the amount of white material designed in the formula and reset it. Add the amount of black material designed in the formula according to the ratio coefficient. Stir the black and white material mixture slowly first (turn on the stopwatch at the same time) to avoid splashing and affecting the ratio; stir at full speed for 8-10 seconds after 2-3 seconds (try to shorten the operation time of the above two steps). Then quickly pour the stirred raw materials into a plastic cup or wooden box and let them foam freely. After the foaming stops, place it in a natural environment and continue to react for 24 hours. In accordance with relevant test standards, a standard sample for UL-94 test is prepared.

[0108] Table 3 Flame retardant polyurethane foaming experimental formula

[0109]

[0110] The standard specimens prepared in the above-mentioned application example 4 are respectively used for the UL-94 horizontal combustion test .

[0111] Sample size: (150±5)×(50±1)mm×thickness. Note: Both the maximum thickness and the minimum thickness must be provided. When the maximum thickness and the minimum thickness are inconsistent, the intermediate thickness must be provided. The interval should not exceed 6mm, and the sample width should not exceed 50mm.

[0112] Sample pretreatment:

[0113] 1. Before testing, the device should be placed in an environment with a temperature of 23±2℃ and a relative humidity of 50±5% for at least 48 hours;

[0114] 2. Before testing, the sample should be placed in an air circulation box at a temperature of 70±1℃ for at least 168 hours, and then cooled in a desiccator. At least place it at room temperature of 25±5℃ for 4 hours;

[0115] Test standards: GB / T 8332-2008, ASTMD4986-03 (foam plastics), ISO3852-88 (soft foam materials)

[0116] Test related introduction: Reference marks are made at 25mm, 60mm, and 125mm of the sample. The flame of the wing top nozzle is applied to a circle of foam plastic placed horizontally on the wire mesh. The fire source is applied for 60s, and the burning rate of the sample is measured.

[0117] Evaluation criteria:

[0118] UL94 HBF The burning rate of the material between the 25mm and 125mm marks does not exceed 40mm / min, or it self-extinguishes before the 125mm mark;

[0119] UL94 HF-1 At least 4 out of a group of 5 samples have a burning time of ≤2s, and any sample has a burning time of ≤10s. After the 60mm mark, the sample is not damaged. After the ignition source is removed or after the 60mm mark, the burning time of the sample does not exceed 30s, and there is no droplet;

[0120] UL94 HF-2 At least 4 out of a group of 5 samples have a burning time of ≤2s, and any sample has a burning time of ≤10s. After the 60mm mark, the sample is not damaged. After the ignition source is removed or after the 60mm mark, the burning time of the sample does not exceed 30s, and the molten droplets ignite the absorbent cotton;

[0121] The average value of all test data is the final test result. The test results are shown in Table 4 below.

[0122] Application Examples UL94 grade Application Example 4 UL94 HBF

[0123] Table 4: Application Example 4 UL-94 horizontal combustion test results

[0124] Currently, polyurethane foam that has not been flame-retardant treated fails the UL-94 horizontal combustion test. However, the test data in Table 4 above show that the polyurethane foam test specimen prepared by adding the multifunctional phosphate polyol flame retardant synthesized by the method of the present invention (Application Example 4) reaches the UL94 HBF level in the UL-94 horizontal combustion test, and the flame retardant performance of the polyurethane foam is significantly improved.

[0125] The present invention utilizes the Mannich reaction mechanism, the carbonyl group of formaldehyde substances is protonated, the amine on diethanolamine undergoes nucleophilic addition to the carbonyl group, and after deprotonation, electron transfer of nitrogen, and water leaving, an imine ion intermediate can be obtained, which, as an electrophilic reagent, attacks the active hydrogen at the ortho-para position on the benzene ring in resorcinol tetraphenyl diphosphate (RDP), thereby obtaining a multifunctional phosphate polyol flame retardant. On the one hand, the multifunctional phosphate polyol flame retardant, as a nucleophilic reagent, can attack the carbonyl group on tert-butyl acetoacetate (TBAA) to obtain a tetrahedral intermediate containing two hydroxyl groups, and then eliminates a molecule of water through proton transfer to generate tert-butyl alcohol and a low-viscosity multifunctional phosphate flame retardant containing a β-dicarbonyl structure; on the other hand, the multifunctional phosphate polyol flame retardant, as a nucleophilic reagent, can attack the carbon atom of the epoxy group on epichlorohydrin (ECH), causing the breakage of the CO bond, opening the epoxy group, and connecting with the hydroxyl group to prepare a low-viscosity multifunctional phosphate flame retardant containing a -Cl structure.

[0126] The low-viscosity multifunctional phosphate flame retardant provided by the present application has a phosphorus-oxygen double bond, a hydroxyl group, a β-dicarbonyl group and a halogen structure. As a reactive flame retardant, the active methylene between its β-dicarbonyl structure can react with isocyanate groups, amine groups, unsaturated double bonds, aldehyde groups, etc., so it can be compounded with general polyether polyols for polyurethane foaming. The presence of phosphorus can effectively improve the flame retardant properties of polyurethane foam products; the presence of halogen structures can further improve the flame retardant properties of polyurethane foams; hydroxyl structures can accelerate the polyurethane foaming process and reduce the surface drying and actual drying time of foaming; most importantly, the low-viscosity multifunctional phosphate flame retardant provided by the present application has the characteristics of low viscosity, is easy to operate, and is easy to mix with other materials according to the formula, and the prepared polyurethane foam products will not have problems such as flame retardant migration and precipitation to the surface, and the flame retardant goal is achieved while improving the physical properties of polyurethane foam.

[0127] It should be noted that the purpose of "lowering to room temperature" in Example 1 of the present invention is to cool to a suitable temperature for adding RDP, and room temperature is preferred, which is 25±5°C.

[0128] Obviously, the above embodiments of the present invention are merely examples for clearly explaining the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is impossible to list all implementation methods here. Any obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A multifunctional phosphate polyol flame retardant, characterized in that: It has the structure shown in the following formula (I): Formula (I); Among them, R1~R 10 H alone or , and R1~R 10 At least one is not an H structure; m=1.

2. A method for preparing the multifunctional phosphate polyol flame retardant according to claim 1, characterized in that: The method comprises the following preparation steps: The formaldehyde substance and diethanolamine are reacted to obtain a reaction intermediate with a hydroxyl structure; the reaction intermediate and resorcinol tetraphenyl diphosphate are subjected to a Mannich reaction to obtain the multifunctional phosphate polyol flame retardant.

3. The method for preparing the multifunctional phosphate polyol flame retardant according to claim 2, characterized in that: The method comprises the following preparation steps: The formaldehyde substance is reacted with diethanolamine at a temperature of 80-100° C. After the reaction is completed, the temperature is maintained at 80-100° C., and unreacted formaldehyde substances are removed by reduced pressure distillation to obtain the reaction intermediate; the reaction intermediate and resorcinol tetraphenyl diphosphate are subjected to a Mannich reaction at a temperature of 80-100° C. After the reaction is completed, a crude multifunctional phosphate polyol flame retardant is obtained, and after post-treatment, a refined multifunctional phosphate polyol flame retardant is obtained.

4. The method for preparing the multifunctional phosphate polyol flame retardant according to claim 3, characterized in that: The post-treatment method comprises: dissolving the crude multifunctional phosphate polyol flame retardant in an organic solvent, adding an appropriate amount of pure water, stirring at 30-50°C, washing multiple times, standing for stratification, removing the upper clear liquid, taking the lower liquid and removing the organic solvent through distillation to obtain the refined multifunctional phosphate polyol flame retardant.

5. The method for preparing the multifunctional phosphate polyol flame retardant according to claim 4, characterized in that: The formaldehyde substance is one of formaldehyde, trioxymethylene and polyformaldehyde; the organic solvent is one of dichloromethane, dichloroethane, carbon tetrachloride and N,N-dimethylformamide.

6. A low-viscosity multifunctional phosphate flame retardant, characterized in that: It has the structure shown in the following formula (II): Formula (II); Among them, R1~R 10 H alone or , and R1~R 10 At least one is not an H structure; m=1; R is or , n is a positive integer.

7. A low-viscosity multifunctional phosphate flame retardant according to claim 6, characterized in that: Its viscosity at 25°C is less than 6000 mPa•s.

8. A method for preparing a low-viscosity multifunctional phosphate flame retardant as claimed in claim 6 or 7, characterized in that: The method comprises the following preparation steps: Under the action of a catalyst, tert-butyl acetoacetate is reacted with the multifunctional phosphate polyol flame retardant according to claim 1 to obtain the low-viscosity multifunctional phosphate flame retardant; Alternatively, epichlorohydrin is reacted with the multifunctional phosphate polyol flame retardant according to claim 1 under a nitrogen or inert gas environment to obtain the low-viscosity multifunctional phosphate flame retardant.

9. The method for preparing a low-viscosity multifunctional phosphate flame retardant according to claim 8, characterized in that: The method comprises the following preparation steps: When the reactant is tert-butyl acetoacetate, tert-butyl acetoacetate and the multifunctional phosphate polyol flame retardant according to claim 1 are reacted at a temperature of 90-120° C. under the action of a catalyst, and after the reaction is completed, the generated tert-butyl alcohol is removed by distillation to obtain the low-viscosity multifunctional phosphate flame retardant; The catalyst is one of potassium hydroxide, sodium hydroxide, potassium carbonate and potassium bicarbonate; When the reactant is epichlorohydrin, epichlorohydrin is reacted with the multifunctional phosphate polyol flame retardant according to claim 1 at a temperature of 90-120° C. in a nitrogen or inert gas environment. After the reaction is completed, unreacted epichlorohydrin is removed by reduced pressure distillation to obtain the low-viscosity multifunctional phosphate flame retardant.

10. The use of the low-viscosity multifunctional phosphate flame retardant according to claim 6 or 7, characterized in that: Used in flame retardant polyurethane foam compositions.

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