CN110054803A - A kind of phosphorus-nitrogen containing flame-proof polyol, preparation method and its preparing the application in resistance combustion polyurethane foam - Google Patents

Abstract

The invention discloses a phosphorus-nitrogen-containing flame-retardant polyol, a preparation method thereof and its application in the preparation of flame-retardant polyurethane foam, wherein the molecular structure of the phosphorus-nitrogen-containing flame-retardant polyol is repeatedly and alternately connected by unit I and unit II. Wherein, each unit I is independently selected from one of the following structures: Each unit II is independently selected from one of the following structures: The invention adopts the salt-forming reaction containing phosphoric acid and amine to introduce the ammonium phosphate structure into the polyol. Compared with adding ammonium phosphate, the flame retardant structure does not precipitate and has better flame retardant effect; the flame retardant polyol also contains phosphine oxide and Ammonium phosphate structure, together to exert their flame retardant effect, so it has better flame retardant effect in polyurethane foam.

Description

A phosphorus-nitrogen-containing flame-retardant polyol, its preparation method and its use in the preparation of flame-retardant polyurethane foam application

technical field

The invention relates to a phosphorus-nitrogen-containing flame-retardant polyol, a preparation method and application thereof in the preparation of flame-retardant polyurethane foam, and belongs to the technical field of flame-retardant polyurethane foam.

Background technique

Polyurethane foam is a flammable material, and the oxygen index of commonly used soft and rigid foam is about 18-20%. Generally, two methods are used for flame retardant treatment: one is to add flame retardants. The flame retardants commonly used in polyurethane foam are dimethyl methylphosphonate (DMMP), triethyl phosphate, tris(2-chloroisopropyl) Propyl) phosphate (TCPP), trichloroethyl phosphate (TCEP), melamine, aluminum hydroxide, expandable graphite, etc.; the other is the use of structural flame retardants, the flame retardant elements phosphorus, nitrogen, halogen, etc. Introduced into polyols or isocyanates through chemical bonds, it has permanent flame retardancy.

Tetrahydroxymethyl quaternary phosphonium salt is an inexpensive industrialized raw material, which is widely used in water treatment, and can be completely degraded into harmless substances after use, which is economical and environmentally friendly. Phosphoric acid, pyrophosphoric acid, polyphosphoric acid, phosphorous acid, hypophosphorous acid and other sources of phosphoric acid are widely available and inexpensive. Therefore, the synthetic route using them has great industrial application prospect.

Trimethylolphosphine can react directly with aliphatic amines efficiently at room temperature. NH and HO-CH ₂ -P remove a molecule of water to form N-CH ₂ -P, and both NH of the primary amine can react. Using this reaction, polyols containing phosphine oxide and amine structures can be synthesized. This polyol has high phosphorus and nitrogen content, good flame retardant effect, and only contains PC bonds and has good hydrolysis resistance. In view of the excellent flame retardant properties of ammonium phosphate in polyurethane foam (ammonium polyphosphate, ammonium dihydrogen phosphate, etc.), the salt-forming reaction containing phosphoric acid and amine is used to introduce the ammonium phosphate structure into the polyol, and then into the molecular chain of the foam, Compared with the additive type ammonium phosphate, it has better flame retardant effect, and the structure of phosphine oxide and ammonium phosphate work together, so that the flame retardant polyol has a better flame retardant effect in polyurethane foam.

SUMMARY OF THE INVENTION

The present invention aims to provide a phosphorus-nitrogen-containing flame-retardant polyol, a preparation method thereof and its application in the preparation of flame-retardant polyurethane foam. The invention adopts the salt-forming reaction containing phosphoric acid and amine to introduce the ammonium phosphate structure into the polyol. Compared with adding ammonium phosphate, the flame retardant structure does not precipitate and has better flame retardant effect; the flame retardant polyol also contains phosphine oxide and Ammonium phosphate structure, together to exert their flame retardant effect, so it has better flame retardant effect in polyurethane foam.

The phosphorus-nitrogen-containing flame retardant polyol of the present invention contains a phosphine oxide structure in its molecule and an amine (and ammonium phosphate) structure, and its molecular structure is formed by repeating and alternately connecting units I and II (units I and II alternate with each other) connected but not connected to itself);

Wherein, each unit I is independently selected from one of the following structures:

Said each unit II is independently selected from one of the following structures:

Wherein, R ₁ , R ₂ , R ₃ , R ₄ are independently selected from non-group (here, non-group refers to only chemical bonds, that is, unpaired electrons, which can be connected with the chemical bonds of unit I, the same below), hydrogen , methyl, ethyl, propyl, butyl, hydroxyethyl, hydroxypropyl, hydroxybutyl, etc.; R ₅ , R ₆ , R ₇ , R ₉ , R ₁₀ , R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ , R ₁₅ , R ₁₆ , R ₁₇ , R ₁₈ , R ₁₉ , R ₂₀ , R ₂₁ , R ₂₂ are each independently selected from no group, hydrogen, methyl, ethyl, hydroxyethyl, hydroxypropyl etc.; R ₈ is selected from ethylene, propylene, butylene, etc.; n is selected from 0, 1 or 2, m is selected from 0, 1, 2 or 3; q and k are independently selected from 0, 1, 2, 3 or 4. If ammonium ion is contained in the polyol, there is also an anion part, which may be an anion formed by one or more of phosphoric acid, phosphorous acid, hypophosphorous acid, pyrophosphoric acid, polyphosphoric acid, and the like.

One of the preparation methods of phosphorus-nitrogen-containing flame-retardant polyol of the present invention comprises the following steps:

Inert gas (deoxygenation) is introduced into the aqueous solution of tetrahydroxymethyl phosphonium sulfate, then the alkali containing barium ion or calcium ion is added to react at 20-80 ° C for 4-10 hours, the precipitate is removed by centrifugation, and the supernatant is collected; Under the protection of inert gas, the supernatant is mixed with an oxygen-free amine aqueous solution, and then reacted at 20-100 ° C for 2-10 hours, the inert gas is removed, and after being oxidized by an oxidant, phosphoric acid-containing aqueous solution is selectively added dropwise. aqueous solution, and finally evaporated to dryness to obtain a phosphorus-nitrogen-containing flame retardant polyol.

The inert gas is selected from nitrogen, argon and the like.

The alkali containing barium ion or calcium ion is selected from one or more of barium hydroxide, barium oxide, calcium hydroxide, calcium oxide and the like.

The molar ratio of the tetrahydroxymethyl phosphonium sulfate to the alkali (calculated as hydroxide ion) containing barium ion or calcium ion is 1:2.

The amine is selected from

One or more of (can contain multiple amines with the same structure but different groups), R ₂₃ and R ₂₄ are independently selected from hydrogen, methyl, ethyl, propyl, butyl, hydroxyethyl, Hydroxypropyl, hydroxybutyl, etc., R ₂₅ , R ₂₆ , R ₂₇ , R ₂₉ , R ₃₀ , R ₃₁ , R ₃₂ , R ₃₃ , R ₃₄ , R ₃₅ , R ₃₆ , R ₃₇ , R ₃₈ , R ₃₉ , R ₄₀ , R ₄₁ , R ₄₂ are independently selected from hydrogen, methyl, ethyl, hydroxyethyl, hydroxypropyl, etc., R ₂₈ is selected from ethylene, propylene, butylene, etc.; the amine The molar ratio to phosphorus atoms is 0.01-5:1.

The mixing may be dropwise addition of the supernatant to the oxygen-free amine aqueous solution, or dropwise addition of the oxygen-free amine aqueous solution to the supernatant.

The oxidant is selected from aqueous hydrogen peroxide, oxygen or air. The oxidation process can be dropwise addition of an aqueous hydrogen peroxide solution with a molar ratio of phosphorus atoms of 1:1, followed by a reaction at room temperature for 1-2 hours, or a reaction with air or oxygen at 20-100° C. for 3-24 hours.

The selective dropwise addition of the phosphoric acid-containing aqueous solution means that the phosphoric acid-containing aqueous solution may or may not be added dropwise. The amount of the phosphoric acid-containing aqueous solution added is sufficient to make the pH value of the system 5-11.

The phosphoric acid-containing aqueous solution is selected from one or more of phosphoric acid solution, phosphorous acid solution, hypophosphorous acid solution, pyrophosphoric acid solution, polyphosphoric acid solution and the like.

In the reaction process, a base containing barium ions or calcium ions is used to directly precipitate sulfate ions, thereby reducing post-treatment steps.

The second preparation method of phosphorus-nitrogen-containing flame retardant polyol of the present invention comprises the following steps:

Inert gas is introduced into the aqueous solution of tetramethylol quaternary phosphonium salt, then alkali is added, and the reaction is carried out at 20-80 ° C for 4-10 hours; under the protection of inert gas, the reaction solution is mixed with an oxygen-free amine aqueous solution, and then React at 20-100°C for 2-10 hours; remove the inert gas, after oxidation by oxidant, selectively add phosphoric acid-containing aqueous solution dropwise, then evaporate the water to dryness, dissolve the product in an alcohol solvent, filter out the precipitate, and evaporate to dryness solvent to obtain a phosphorus-nitrogen-containing flame retardant polyol.

The inert gas is selected from nitrogen, argon and the like.

The tetrahydroxymethyl quaternary phosphonium salt is selected from one or more of tetrahydroxymethyl phosphonium chloride, tetrahydroxymethyl phosphonium bromide, tetrahydroxymethyl phosphonium sulfate, and the like.

The base is selected from one or more of sodium hydroxide, potassium hydroxide, calcium oxide, calcium hydroxide, sodium carbonate, potassium carbonate and the like.

The molar ratio of the tetrahydroxymethyl quaternary phosphonium ion to the alkali (calculated as hydroxide ion) is 1:1.

The amine is selected from

One or more of (can contain multiple amines with the same structure but different groups), R ₂₃ and R ₂₄ are independently selected from hydrogen, methyl, ethyl, propyl, butyl, hydroxyethyl, Hydroxypropyl, hydroxybutyl, etc., R ₂₅ , R ₂₆ , R ₂₇ , R ₂₉ , R ₃₀ , R ₃₁ , R ₃₂ , R ₃₃ , R ₃₄ , R ₃₅ , R ₃₆ , R ₃₇ , R ₃₈ , R ₃₉ , R ₄₀ , R ₄₁ , R ₄₂ are independently selected from hydrogen, methyl, ethyl, hydroxyethyl, hydroxypropyl, etc., R ₂₈ is selected from ethylene, propylene, butylene, etc.; the amine The molar ratio to phosphorus atoms is 0.01-5:1.

The mixing may be dropwise addition of the reaction to an aqueous solution of anoxic amine, or dropwise addition of an aqueous solution of anoxic amine to the reaction solution.

The oxidant is selected from aqueous hydrogen peroxide, oxygen or air. The oxidation process can be dropwise addition of an aqueous hydrogen peroxide solution with a molar ratio of phosphorus atoms of 1:1, followed by a reaction at room temperature for 1-2 hours, or a reaction with air or oxygen at 20-100° C. for 3-24 hours.

The selective dropwise addition of the phosphoric acid-containing aqueous solution means that the phosphoric acid-containing aqueous solution may or may not be added dropwise. The amount of the phosphoric acid-containing aqueous solution added is sufficient to make the pH value of the system 5-11.

The phosphoric acid-containing aqueous solution is selected from one or more of phosphoric acid solution, phosphorous acid solution, hypophosphorous acid solution, pyrophosphoric acid solution, polyphosphoric acid solution and the like.

The alcoholic solvent is selected from one or more of methanol, ethanol, propanol, butanol and the like.

The reaction process does not use toxic heavy metal barium ions, and the tetrahydroxymethyl quaternary phosphonium salt is not limited to tetrahydroxymethyl phosphonium sulfate.

The reaction process of the present invention is illustrated as follows:

The first step: tetrahydroxymethyl quaternary phosphonium ion and hydroxide ion react to generate trimethylol phosphine. In the first preparation method, sulfate ions and barium ions or calcium ions form precipitates.

The second step: trimethylol phosphine reacts with amine, and hydroxymethyl and N-H remove a molecule of water to generate amine methyl group. Every N-H on the amine can react.

Step 3: The trialkylphosphine is oxidized to trialkylphosphine oxide by hydrogen peroxide or oxygen.

Step 4: The amine reacts with phosphoric acid to form ammonium phosphate.

The application of the phosphorus-nitrogen-containing flame-retardant polyol of the present invention is to partially or completely replace the phosphorus-nitrogen-containing flame-retardant polyol with conventional polyether and/or polyester polyols, with isocyanate compounds, additives, flame retardants, etc. Carry out foaming to prepare flame retardant polyurethane foam (soft foam, rigid foam, etc.).

Compared with the prior art, the beneficial effects of the present invention are embodied in:

1. The raw materials used are cheap and easy to obtain, most of them are low-toxic or non-toxic, the reaction process conditions are mild and water (and alcohol) is used as the solvent, and the by-products only have formaldehyde and non-toxic salts, which can be collected and made into products, There is no pollutant emission, and it has a good industrial application prospect.

2. The flame-retardant polyol has a high phosphorus content and only contains phosphorus-carbon bonds. Compared with the phosphate ester, the flame-retardant polyol is more resistant to hydrolysis, making the polyurethane foam more stable and able to maintain high flame retardancy for a long time.

3. The ammonium phosphate structure is introduced into the polyol by the salt-forming reaction containing phosphoric acid and amine. Compared with the addition of ammonium phosphate, the flame retardant structure will not precipitate and the flame retardant effect is better; the flame retardant polyol also contains phosphine oxide and Ammonium phosphate structure, together to exert their flame retardant effect, so it has better flame retardant effect in polyurethane foam.

Detailed ways

Further description is given below with specific examples: the raw materials used in the present invention are all commercially available.

Example 1:

In a three-necked flask connected with a nitrogen inlet and outlet, add 40.0 g of 75% tetrahydroxymethyl phosphonium sulfate aqueous solution, pass nitrogen for 2 hours, add 23.3 g of barium hydroxide octahydrate, and react for 4 hours to remove the precipitate by centrifugation to obtain a supernatant. . Under nitrogen protection, 14.6 g of 30% methylamine aqueous solution was slowly added dropwise to the supernatant, and then 16.6 g of 40% dimethylamine aqueous solution was slowly added dropwise, and stirring was continued for 4 hours after the dropwise addition was completed. Then, nitrogen was removed, 16.7 g of 30% hydrogen peroxide aqueous solution was slowly added dropwise, the reaction was continued for 1 hour after the dropwise addition was completed, and finally the water was evaporated to dryness to obtain a polyol. The structural formula of the target product is:

Example 2:

First, 25 parts of the polyol in Example 1, 50 parts of polyether polyol 5623, 25 parts of polymer polyol 2045, 1.1 parts of silicone oil, 0.18 parts of stannous octoate, 0.28 parts of A33, 3.5 parts of dichloromethane and 3.2 parts of The water is mixed well. Then add 46 parts of TDI, pour it into a 40°C mold after high-speed stirring, put it into an 80°C oven for curing for 24 hours after foaming, and obtain a flame-retardant polyurethane flexible foam. After testing, the oxygen index of flame retardant polyurethane flexible foam is 23% (without adding flame retardant polyol, the oxygen index of flexible foam when adding 75 parts of polyether polyol is 18.5%).

Example 3:

In a three-necked flask connected with a nitrogen inlet and outlet, add 40.0 g of 75% tetrahydroxymethyl phosphonium sulfate aqueous solution, pass nitrogen for 2 hours, add 23.3 g of barium hydroxide octahydrate, and react for 4 hours to remove the precipitate by centrifugation to obtain a supernatant. . Under nitrogen protection, 13.8 g of 30% methylamine aqueous solution was slowly added dropwise to the supernatant, and the stirring was continued for 4 hours after the dropwise addition was completed. Then, nitrogen was removed, 16.7 g of 30% hydrogen peroxide aqueous solution was slowly added dropwise, the reaction was continued for 1 hour after the dropwise addition was completed, and finally the water was evaporated to dryness to obtain a polyol.

The structural formula of the target product is:

Example 4:

First, mix 30 parts of flame retardant polyol in Example 3, 70 parts of polyether polyol 4110, 1 part of A33, 0.5 part of dibutyltin dilaurate, 2 parts of water, 2 parts of silicone oil and 3 parts of triethanolamine. Then add 150 parts of polymerized MDI (PM-200), stir at a high speed, pour it into a mold, put it into an oven at 80 ° C for curing for 24 hours after foaming, and obtain a flame-retardant rigid polyurethane foam. Burning polyol, when adding 100 parts of polyether polyol 4110, the oxygen index of hard foam is 20%).

Example 5:

40.0g of 75% tetrahydroxymethyl phosphonium sulfate aqueous solution was added to a three-necked flask connected with a nitrogen inlet and outlet. After nitrogen was introduced for 2 hours, 5.90g of sodium hydroxide was slowly added. The aqueous solution of diethanolamine was continuously stirred for 4 hours after the dropwise addition was completed. Then, nitrogen was removed, 16.7 g of 30% aqueous hydrogen peroxide solution was slowly added dropwise, the reaction was continued for 1 hour after the dropwise addition was completed, and then 85% aqueous phosphoric acid solution was slowly added dropwise until the solution became neutral. Then the water is evaporated to dryness, the product is dissolved in ethanol, the sodium sulfate precipitate is filtered off, and the ethanol is evaporated to dryness, repeating once to obtain a polyol. The structural formula of the target product is (the anion part contains monohydrogen phosphate and dihydrogen phosphate ions):

Example 6:

The experimental process is the same as in Example 5 except that the 85% phosphoric acid aqueous solution is not added dropwise. The structural formula of the target product is:

Example 7:

First, mix 50 parts of polyol in Example 5 or Example 6, 50 parts of polyether polyol 4110, 1 part of A33, 0.5 part of dibutyltin dilaurate, 2 parts of water, 2 parts of silicone oil and 3 parts of triethanolamine. . Then add 150 parts of polymerized MDI (PM-200), stir at a high speed, pour it into a mold, put it into an oven at 80° C. for curing for 24 hours after foaming, and obtain a flame-retardant rigid polyurethane foam. The oxygen index of the rigid foam prepared by adding the polyol in Example 6 is 23%, and the oxygen index of the rigid foam prepared by adding the polyol in Example 5 is 24.5%, indicating that the polyol containing both phosphine oxide and ammonium phosphate structures has better performance Flame retardant effect.

Claims (10)

1. a kind of phosphorus-nitrogen containing flame-proof polyol, it is characterised in that:

Its molecular structure is repeated alternately to be formed by connecting by unit I and unit II；

Wherein, each unit I is independently selected from such as one of flowering structure:

Each unit II is independently selected from such as one of flowering structure:

Wherein, R₁、R₂、R₃、R₄Separately selected from no group, hydrogen, methyl, ethyl, propyl, butyl, ethoxy, hydroxypropyl, Hydroxyl butyl etc.；R₅、R₆、R₇、R₉、R₁₀、R₁₁、R₁₂、R₁₃、R₁₄、R₁₅、R₁₆、R₁₇、R₁₈、R₁₉、R₂₀、R₂₁、R₂₂Separately it is selected from Without group, hydrogen, methyl, ethyl, ethoxy, hydroxypropyl etc.；R₈Selected from ethylidene, propylidene, butylidene etc.；N is selected from 0,1 or 2, M is selected from 0,1,2 or 3；Q and k is separately selected from 0,1,2,3 or 4.

2. a kind of preparation method of phosphorus-nitrogen containing flame-proof polyol described in claim 1, it is characterised in that include the following steps:

It is passed through inert gas in tetra methylol sulfuric acid phosphonium aqueous solution, the alkali containing barium ions or calcium ion is then added, in 20-80 It is reacted 4-10 hours at DEG C, is centrifuged off precipitating, leaves and takes supernatant；Under inert gas protection, by the supernatant and anaerobic Amine aqueous solution mixing, then react 2-10 hours at 20-100 DEG C, removes inert gas, after oxidizing, select The aqueous solution of phosphoric acid is added dropwise in selecting property, is finally evaporated water and obtains phosphorus-nitrogen containing flame-proof polyol.

3. preparation method according to claim 2, it is characterised in that:

The alkali containing barium ions or calcium ion is selected from one of barium hydroxide, barium monoxide, calcium hydroxide, calcium oxide etc. or several Kind；The molar ratio of the tetra methylol sulfuric acid phosphonium and the alkali containing barium ions or calcium ion is 1:2.

4. preparation method according to claim 2, it is characterised in that:

The amine is selected from In It is one or more；

Wherein, R₂₃、R₂₄It is separately selected from hydrogen, methyl, ethyl, propyl, butyl, ethoxy, hydroxypropyl, hydroxyl butyl etc., R₂₅、R₂₆、R₂₇、R₂₉、R₃₀、R₃₁、R₃₂、R₃₃、R₃₄、R₃₅、R₃₆、R₃₇、R₃₈、R₃₉、R₄₀、R₄₁、R₄₂Separately it is selected from hydrogen, first Base, ethyl, ethoxy, hydroxypropyl etc., R₂₈Selected from ethylidene, propylidene, butylidene etc.；The molar ratio of the amine and phosphorus atoms is 0.01-5:1。

5. preparation method according to claim 2, it is characterised in that:

The oxidant is selected from aqueous hydrogen peroxide solution, oxygen or air；Oxidation process can be dropwise addition and phosphorus atoms molar ratio Reacted at room temperature 1-2 hours after the aqueous hydrogen peroxide solution of 1:1, or be passed through at 20-100 DEG C of air or oxygen react 3-24 it is small When.

6. a kind of preparation method of phosphorus-nitrogen containing flame-proof polyol described in claim 1, it is characterised in that include the following steps:

It is passed through inert gas in tetra methylol quaternary phosphine saline solution, alkali is then added, is reacted 4-10 hours at 20-80 DEG C； Under inert gas protection, reaction solution is mixed with the aqueous solution of the amine of anaerobic, is then reacted 2-10 hours at 20-100 DEG C； Inert gas is removed, after oxidizing, the aqueous solution of phosphoric acid is added dropwise in selectivity, is then evaporated water, product is dissolved in alcohol Precipitating, then solvent evaporated are filtered off after class solvent, obtain phosphorus-nitrogen containing flame-proof polyol.

7. preparation method according to claim 6, it is characterised in that:

The tetra methylol quaternary alkylphosphonium salt is in tetrakis hydroxymethyl phosphonium chloride, tetra methylol phosphonium bromide, tetra methylol sulfuric acid phosphonium etc. It is one or more；

The alkali is selected from one of sodium hydroxide, potassium hydroxide, calcium oxide, calcium hydroxide, sodium carbonate, potassium carbonate etc. or more Kind；

The molar ratio of the tetra methylol quaternary phosphine ion and alkali is 1:1.

8. preparation method according to claim 6, it is characterised in that:

The amine is selected from In It is one or more；

Wherein, R₂₃、R₂₄It is separately selected from hydrogen, methyl, ethyl, propyl, butyl, ethoxy, hydroxypropyl, hydroxyl butyl etc., R₂₅、R₂₆、R₂₇、R₂₉、R₃₀、R₃₁、R₃₂、R₃₃、R₃₄、R₃₅、R₃₆、R₃₇、R₃₈、R₃₉、R₄₀、R₄₁、R₄₂Separately it is selected from hydrogen, first Base, ethyl, ethoxy, hydroxypropyl etc., R₂₈Selected from ethylidene, propylidene, butylidene etc.；The molar ratio of the amine and phosphorus atoms is 0.01-5:1。

9. preparation method according to claim 6, it is characterised in that:

The oxidant is selected from aqueous hydrogen peroxide solution, oxygen or air；Oxidation process can be dropwise addition and phosphorus atoms molar ratio Reacted at room temperature 1-2 hours after the aqueous hydrogen peroxide solution of 1:1, or be passed through at 20-100 DEG C of air or oxygen react 3-24 it is small When.

10. a kind of application of phosphorus-nitrogen containing flame-proof polyol described in claim 1, it is characterised in that: be to hinder the phosphorus-nitrogen containing Polyol moiety or the completely conventional polyethers of substitution and/or polyester polyol are fired, with isocyanate compound, auxiliary agent, fire retardant Resistance combustion polyurethane foam is prepared etc. foaming is carried out.