Preparation method and use of a suspension-type structural flame-retardant polyether polyol

Abstract

The present invention provides a method for preparing a suspension-type structured flame-retardant polyether polyol and its use, belonging to the field of polymer synthesis. The method includes: at 0-10 °C, introducing a mixture of phosphite, carbon tetrachloride and anhydrous tetrahydrofuran, dropping a mixture of N-allylmethylamine, triethylamine and anhydrous tetrahydrofuran, raising the temperature to 15-30 °C, and reacting for 6-12 h to obtain allylmethylaminophosphate; at 110-130 °C, a small molecule alcohol compound, propylene oxide and allyl glycidyl ether react to obtain a polyether polyol with double bonds in the side chain; mixing allylmethylaminophosphate, an initiator, a chain transfer agent and isopropanol, and introducing them into the polyether polyol with double bonds in the side chain for reaction to obtain the flame-retardant polyether polyol. This suspension-type structured flame-retardant polyether polyol has the characteristics of a relatively high content of flame-retardant elements, high tensile strength, high tear strength and low Shore hardness, and can be widely used in the preparation of flame-retardant polyurethane products.

Description

Technical Field

[0001] The invention belongs to the field of polymer synthesis, and in particular relates to a preparation method and application of a suspended structure flame-retardant polyether polyol. Background Art

[0002] Polyurethane materials are widely used in clothing, shoes, hats, building exterior walls, pipelines, aerospace, furniture, automobiles, medical and other fields. However, ordinary polyurethane materials have poor flame retardant properties, such as low oxygen index, easy combustion, and high smoke density. With the continuous expansion of its application fields, the requirements for its flame retardant properties are also getting higher and higher.

[0003] At present, the main way to improve the flame retardant properties of polyurethane materials is to add flame retardants containing phosphorus, chlorine, bromine and other flame retardant elements. According to different methods of use, flame retardants can be divided into two categories: additive and reactive. Additive flame retardants are flame retardants that can be directly added to the material and do not react physically or chemically with the reactants. They have the advantages of high flame retardancy and low price, and are widely used in industrial production. However, this type of flame retardant has the disadvantages of not lasting flame retardant effect, poor compatibility and easy reduction of polyurethane material performance. Reactive flame retardant refers to polyols or isocyanates containing flame retardant elements. This type of material does not have the compatibility problems faced by additive flame retardants, and the amount used is also small. It has little effect on the mechanical properties of polyurethane materials. It can also introduce corresponding functional groups or side chains as needed to meet special performance requirements. It is the most popular type of flame retardant, also known as structural flame retardant. However, the development of reactive flame retardant products is difficult. In the prior art, there is a lack of flame-retardant polyurethane elastomer coatings suitable for the production of soft furniture. Summary of the invention

[0004] The object of the present invention is to provide a method for preparing a suspended structure flame-retardant polyether polyol. The obtained suspended structure flame-retardant polyether polyol has the characteristics of high content of flame-retardant elements, high tensile strength and tear strength, and low Shore hardness. It can be widely used in the preparation of flame-retardant polyurethane products, and is particularly suitable for producing flame-retardant polyurethane elastomer coatings for soft furniture.

[0005] The purpose of the present invention is achieved by the following technical solutions:

[0006] A method for preparing a suspended structure flame-retardant polyether polyol comprises the following steps:

[0007] (1) In a nitrogen atmosphere, a mixture of phosphite, carbon tetrachloride and anhydrous tetrahydrofuran is added to a reaction kettle at 0-10° C., and after stirring, a mixture of N-allylmethylamine, triethylamine and anhydrous tetrahydrofuran is added dropwise. After the addition is complete, the temperature is raised to 15-30° C. and reacted for 6-12 hours under stirring to obtain allylmethylphosphamidate;

[0008] (2) at 110-130° C., a small molecule alcohol compound, propylene oxide and allyl glycidyl ether undergo a polymerization reaction under the action of a catalyst, potassium hydroxide, to obtain a polyether polyol having a double bond in the side chain;

[0009] (3) Allyl methylamino phosphate, an initiator, a chain transfer agent, and isopropanol are mixed to prepare a formulation; the polyether polyol having a double bond in the side chain is put into a reaction kettle as a base material; the formulation is introduced into the base material to perform a free radical polymerization reaction at 110-130° C. to obtain the suspended structure flame retardant polyether polyol.

[0010] In the present invention, the phosphite in step (1) is one or more of dimethyl phosphite, diethyl phosphite and diphenyl phosphite.

[0011] In the present invention, the molar ratio of the phosphite to N-allylmethylamine in step (1) is 1:1-1.5; the molar ratio of the phosphite, carbon tetrachloride and triethylamine is 1:1-1.5:1-1.5.

[0012] In the present invention, the small molecule alcohol compound in step (2) is one or more of isopropanol, n-butanol, propylene glycol, diethylene glycol, trimethylolpropane, glycerol, mannitol, sorbitol, pentaerythritol, sucrose and xylitol.

[0013] In the present invention, the mass ratio of the sum of the mass of propylene oxide and allyl glycidyl ether to the small molecule alcohol compound in step (2) is 720-780:200-250, and the mass ratio of propylene oxide to allyl glycidyl ether is 1:1.8-2.1.

[0014] In the present invention, the initiator in step (3) is an azo initiator, and the chain transfer agent is a sulfur-containing compound.

[0015] In the present invention, the mass ratio of the polyether polyol containing double bonds in the side chain to allyl methylaminophosphorate is 450:1600-2000.

[0016] The present invention also provides use of the suspended structure flame-retardant polyether polyol in preparing a flame-retardant polyurethane material.

[0017] The present invention also provides use of the suspended structure flame-retardant polyether polyol in preparing a flame-retardant polyurethane elastomer coating for soft furniture.

[0018] The preparation method of structural flame-retardant polyether polyol comprises the following steps: firstly, anhydrous tetrahydrofuran is used as an organic solvent, triethylamine is used as a catalyst, and carbon tetrachloride, phosphite, and N-allylmethylamine are reacted through an Atherton-Todd reaction to generate allylmethylaminophosphoester; then, small molecule alcohol compounds, propylene oxide, and allyl glycidyl ether are subjected to anionic polymerization reaction under the action of potassium hydroxide as a catalyst to obtain polyether polyol having a double bond in a molecular side chain; finally, the polyether polyol and allylmethylaminophosphoester are subjected to free radical polymerization reaction under the action of an initiator and a chain transfer agent to finally obtain a suspended structural flame-retardant polyether polyol.

[0019] Compared with the prior art, the present invention has the following effects: Structurally, the suspension-type flame-retardant polyether polyol of the present invention has the characteristics of a short polyether main chain and a long side chain. Since its side chain is longer than the main chain and contains a phosphoramide structure on the side chain, its overall structure presents a situation in which a string of phosphoramide structures are suspended on a short main chain. Therefore, this suspension-type flame-retardant polyether polyol has the characteristics of a high content of flame-retardant elements, which can maximize the flame retardancy of polyurethane materials. Since it is reactive, migration will not occur, and it has good compatibility, so it has little effect on the mechanical properties of polyurethane materials. The flame-retardant polyether polyol does not contain halogen, meets environmental protection requirements, and the synergistic effect of nitrogen and phosphorus in the phosphoramide structure provides excellent flame retardancy and heat resistance. In addition, the polyurethane elastomer prepared by the suspension-type flame-retardant polyether polyol has high tensile strength and tear strength, low Shore hardness, and can be widely used in the preparation of flame-retardant polyurethane products, especially suitable for the production of flame-retardant polyurethane elastomer coatings for soft furniture. DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with embodiments, but the protection scope of the present invention is not limited thereto, and any changes made to the technical solution of the present invention by professionals in the field should all fall within the protection scope of the present invention.

[0021] The methods are conventional methods unless otherwise specified, and the raw materials are available from public commercial channels unless otherwise specified.

[0022] Example 1

[0023] According to the following method, allylmethylphosphonamidate was prepared by Atherton-Todd reaction: a mixture of 11 mol of dimethyl phosphite, 12.1 mol of carbon tetrachloride and 66 mol of anhydrous tetrahydrofuran was added to a reactor under nitrogen atmosphere at 5°C, and after stirring, a mixture of 11.55 mol of N-allylmethylamine, 12.1 mol of triethylamine and 3 mol of anhydrous tetrahydrofuran was added dropwise, and the addition was completed over 2 hours; then the temperature was raised to 25°C, and the reaction was carried out under stirring at 25°C for 10 hours; finally, the material was discharged after filtration and vacuum (temperature 100°C, pressure -0.1MPa) to obtain allylmethylphosphonamidate, and the reaction formula is as follows:

[0024]

[0025] The polyether polyol containing double bonds on the molecular side chain was prepared by anionic polymerization reaction according to the following method: 212 g of diethylene glycol and 2.42 g of catalyst KOH were added to a reaction kettle, stirring was started, nitrogen was replaced 3 times, and then the vacuum was evacuated to a vacuum degree of -0.1 MPa, and the temperature was raised to 120°C while evacuating; the temperature was kept at 120°C for 1 hour under a vacuum degree of -0.1 MPa for dehydration; then, the vacuum valve was closed and the heating was stopped, and 30 g of a mixture of propylene oxide and allyl glycidyl ether (the mass ratio of allyl glycidyl ether to propylene oxide was 1.966:1) was introduced, and when the pressure dropped and the temperature rose, the remaining 727 g mixture of propylene oxide and allyl glycidyl ether (the mass ratio of allyl glycidyl ether to propylene oxide is 1.966:1), during the continuous introduction, the pressure is maintained at 0.3 MPa and the temperature is controlled at 120°C; after the feeding is completed, keep warm at 120°C for 1 hour, and then evacuate for 1 hour; add 48.45g water and 12.1g refined agent CP-2 (purchased from Dallas Special Adsorbent Co., Ltd.), continue stirring at 120°C for 1 hour, and then evacuate for 1 hour; finally, filter and cool to room temperature to obtain a polyether polyol with double bonds in the side chain. After testing, its hydroxyl value is 249.5mgKOH / g and the molecular weight is 449.7, and it is set aside.

[0026] According to the following method, a flame-retardant polyether polyol with a hanging structure is prepared by free radical polymerization: 450g of the above-mentioned polyether polyol with double bonds in the side chain is added to a reactor as a base material under a nitrogen atmosphere; 1790g of allylmethylaminophosphoric acid dimethyl ester, 450g of isopropanol, 5.6g of initiator dimethyl azobisisobutyrate, and 3.36g of chain transfer agent n-dodecyl mercaptan are mixed evenly to prepare ingredients; the stirring device of the reactor is turned on, and the ingredients are passed into the base material for free radical polymerization reaction, and the reaction temperature is controlled at 120°C. After the feeding is completed, stirring is continued at 120°C for 1h, and then vacuum is drawn at 125°C for 1h, and the material is discharged to obtain a flame-retardant polyether polyol with a hanging structure, and its phosphorus content (mass percentage concentration) is 13.84%, and the nitrogen content (mass percentage concentration) is 6.25%. The reaction formula is as follows:

[0027]

[0028] Comparative Example 1

[0029] According to the same method as in Example 1, allyl methylphosphonamidate was prepared.

[0030] According to the following method, 1-methylaminophosphoric acid dimethyl ester-2,3-epoxypropane is prepared by in-situ epoxidation reaction: at 40° C., 1.8 mol of allyl methylaminophosphoric acid dimethyl ester is added to a reaction kettle, 1.6 mol of formic acid is added, the temperature is raised to 50° C., 1.8 mol of hydrogen peroxide (added in the form of a 30% by mass aqueous solution of hydrogen peroxide) is added dropwise at 50° C., after the addition is completed for 1 hour, the reaction is continued at 50° C. under stirring for 6 hours; finally, the material is washed with water and discharged after reduced pressure distillation to obtain 1-methylaminophosphoric acid dimethyl ester-2,3-epoxypropane, and the reaction formula is as follows:

[0031]

[0032] A flame retardant polyether polyol control was prepared by coordination polymerization as follows: 100 g of polyether polyol N-204 (propylene glycol polyoxypropylene ether, molecular weight 400, purchased from Jiangsu Zhongshan New Materials Co., Ltd.) and 150 ppm of a double metal cyanide complex catalyst (DMC catalyst, purchased from Huayin Zhongshi Fine Chemical Co., Ltd.) were added to a reactor, stirring was started, nitrogen was replaced 3 times, and the mixture was evacuated to a vacuum degree of -0.1 MPa, and the temperature was raised to 150°C while evacuating the mixture; the mixture was kept at 150°C for 1 h at a vacuum degree of -0.1 MPa, and then the vacuum valve was closed and heating was stopped, and 30 g of propylene oxide and 1-methylaminophosphoric acid dimethyl ester were introduced. -2,3-propylene oxide mixture (propylene oxide and 1-methylaminophosphoric acid dimethyl ester-2,3-propylene oxide mass ratio of 4:11), when the pressure drops and the temperature rises, continue to pass 420g propylene oxide and 1-methylaminophosphoric acid dimethyl ester-2,3-propylene oxide mixture (propylene oxide and 1-methylaminophosphoric acid dimethyl ester-2,3-propylene oxide mass ratio of 4:11), in the process of continuous passing, control pressure of 0.1MPa, temperature of 145℃; after the feeding is completed, keep warm at 145℃ for 1h, then vacuum for 1h; finally cool to room temperature, and obtain a control flame retardant polyether polyol, the phosphorus content of which is 9.54%, the nitrogen content of which is 4.31%. It is particularly pointed out that the amount of DMC catalyst used in each kilogram of reactants (polyether polyol N-204, propylene oxide and 1-methylaminophosphoric acid dimethyl ester-2,3-propylene oxide) is 150mg.

[0033] The suspended structure flame retardant polyether polyol in Example 1 is compared with the control flame retardant polyether polyol in Comparative Example 1, and polyurethane elastomers are prepared according to the following formula, and their performance is tested. The polyurethane elastomer formula includes two components A and B. 100 parts by mass of the suspended structure flame retardant polyether polyol (Example 1) or the control flame retardant polyether polyol (Comparative Example 1) and 0.02 parts by mass of the catalyst stannous octoate T-9 (purchased from Evonik Industries) are mixed to obtain component A; component B is 15 parts by mass of modified isocyanate 8019 (purchased from Wanhua Chemical). Component A and component B prepared by the suspended structure flame retardant polyether polyol are mixed evenly, poured into a mold, and matured to obtain a polyurethane elastomer. Component A and component B prepared by the control flame retardant polyether polyol are mixed evenly, poured into a mold, and matured to obtain a polyurethane elastomer.

[0034] The performance of the prepared polyurethane elastomer was tested, and the test results are shown in Table 1.

[0035] Table 1 Properties of various polyurethane elastomers

[0036]

[0037] As can be seen from Table 1, the use of a hanging structure flame-retardant polyether polyol can greatly improve the flame retardancy of polyurethane elastomers. It has high tensile strength and tear strength, low Shore hardness, and can be widely used in the preparation of flame-retardant polyurethane products, especially suitable for the production of flame-retardant polyurethane elastomer coatings for soft furniture. Structurally, the hanging structure flame-retardant polyether polyol prepared by the present invention has the characteristics of a short polyether main chain and a long side chain. Since its side chain is longer than the main chain and contains a phosphoramide structure on the side chain, its overall structure presents a trend of a string of phosphoramide structures hanging on a short main chain. Therefore, this special hanging structure can make the polyether polyol have a high content of flame-retardant elements, which can greatly improve the flame retardancy of polyurethane. In addition, the flame-retardant polyether polyol does not contain halogen, and the nitrogen-phosphorus synergistic effect of the phosphoramide structure provides excellent flame retardancy and heat resistance. In the comparative example, the flame-retardant element content of the flame-retardant polyether polyol is lower than that of the hanging structure flame-retardant polyether polyol, and the flame retardant effect is relatively poor.

Claims

1. Preparation method of a suspension-type structured flame-retardant polyether polyol, characterized in that it comprises the following steps: (1) Under a nitrogen atmosphere and at 0 - 10 °C, a mixture of phosphite, carbon tetrachloride, and anhydrous tetrahydrofuran is added into a reaction kettle. After starting stirring, a mixture of N-allylmethylamine, triethylamine, and anhydrous tetrahydrofuran is added dropwise. After the dropwise addition is completed, the temperature is raised to 15 - 30 °C, and the reaction is carried out for 6 - 12 h under stirring to obtain allylmethylaminophosphate; (2) At 110 - 130 °C, a polymerization reaction occurs among small molecule alcohol compounds, propylene oxide, and allyl glycidyl ether under the action of the catalyst potassium hydroxide to obtain a polyether polyol with double bonds in the side chain; (3) Allylmethylaminophosphate, an initiator, a chain transfer agent, and isopropyl alcohol are mixed to form a formulation; the polyether polyol with double bonds in the side chain is put into the reaction kettle as the base material; the formulation is introduced into the base material, and a free radical polymerization reaction is carried out at 110 - 130 °C to obtain the suspension-type structured flame-retardant polyether polyol.

2. The preparation method of the flame-retardant polyether polyol according to claim 1, characterized in that: in step (1), the phosphite is one or more of dimethyl phosphite, diethyl phosphite, and diphenyl phosphite.

3. The preparation method according to claim 1 or 2, characterized in that in step (1), the molar ratio of the phosphite to N-allylmethylamine is 1:1 - 1.5; the molar ratio of the phosphite, carbon tetrachloride, and triethylamine is 1:1 - 1.5:1 - 1.

5.

4. The preparation method of the flame-retardant polyether polyol according to claim 3, characterized in that: in step (2), the small molecule alcohol compounds are one or more of isopropyl alcohol, n-butanol, propylene glycol, diethylene glycol, trimethylolpropane, glycerol, mannitol, sorbitol, pentaerythritol, sucrose, and xylitol.

5. The preparation method according to claim 4, characterized in that in step (2), the mass ratio of the sum of the masses of propylene oxide and allyl glycidyl ether to the mass of the small molecule alcohol compounds is 720 - 780:200 - 250, and the mass ratio of propylene oxide to allyl glycidyl ether is 1:1.8 - 2.

1.

6. The preparation method of the flame-retardant polyether polyol according to claim 5, characterized in that: in step (3), the initiator is an azo initiator, and the chain transfer agent is a sulfur-containing compound.

7. The preparation method of the flame-retardant polyether polyol according to claim 6, characterized in that the mass ratio of the polyether polyol with double bonds in the side chain to allylmethylaminophosphate is 450:1600 - 2000.

8. Use of the suspension-type structured flame-retardant polyether polyol according to claim 1 for preparing a flame-retardant polyurethane material.

9. Use of the suspension-type structured flame-retardant polyether polyol according to claim 1 for preparing a flame-retardant polyurethane elastomer coating for soft furniture.

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