CN1230459C - Process for preparing polyurea polyol - Google Patents

Abstract

The present invention relates to a method for preparing polyurea polybasic alcohol. First of all, polyether polybasic alcohol and polybasic amine are mixed with solvents, the mixture of isocyanate or isocyanate and polyatomic alcohol is added to the polybasic alcohol and the polybasic amine which are mixed with the solvents, and vacuum elimination is carried out after a reaction. The isocyanate is fatty or aromatic polyisocyanate, and the polyether polyatomic alcohol generally has the hydroxyl value of 20 to 60, the functional group of 2 to 4 and the molecular weight of 2000 to 8000; the polybasic amine is a fatty, alicyclic and aromatic compound with primary amine bases or secondary amine bases, and the solvents are polar and nonpolar solvents. The present invention adds a proper amount of solvents in a reaction system, reduces the integral viscidity of the reaction system in a reaction vessel, improves the dispersivity of generated polyurea particles and the shape of the particles, and reduces the influence of water on the viscidity of products. Polyurethane foam made by using the polyurea polyatomic alcohol prepared by the present invention as raw materials has high bearing capacity and favorable flame resisting performance which can reaches a self extinguishing level.

Description

A kind of preparation method of polyurea polyol

(1) Technical field

The invention relates to the field of polyurethane foam plastics, in particular to a preparation method of polyurea polyol.

(2) Background technology

Since the industrialization of polyurethane, due to its many advantages, it has developed extremely rapidly, and as an important component of polyurethane, polyol has also developed rapidly, and new varieties have emerged continuously, which are used in different fields. Polyurethane foams are prepared by reacting polyols and polyisocyanates in the presence of various additives. Polyols used for foams are usually made of active hydrogen-containing initiators and oxyalkylene compound monomers under the action of ion catalysts. The polyol molecular weight obtained is generally between 500 and 8000, and the functional group is between 2 and 5. In order to improve the load-carrying properties and flame retardancy of foams, polyols need to be modified, and filling modification is one of the main methods, which can generally be divided into two categories, namely partially reactive and non-reactive organic filling modification. Since there is no chemical reaction between the non-reactive organic filler particles and the polyether dispersion medium, there is an obvious interface. It has the same disadvantages as the inorganic filler, such as it is difficult to prepare and maintain the dispersion state, and it is easy to produce precipitation, which makes a certain part of the foam Some physical properties are lost, pumping is difficult and other disadvantages. There are two kinds of partially reactive filling modification in the industry. One is to prepare polymer polyols by grafting polyvinyl monomers (such as acrylonitrile, styrene, etc.) in polyols. The current market share The rate is relatively large, but the unreacted monomers such as acrylonitrile and styrene remaining in the product after the reaction are highly toxic and the product smell is also large; another modification method is to prepare polyurea polyol, which can be reacted with polyisocyanate Produce high-load and high-modulus polyurethane products, which can improve certain properties of PU products, such as enhancing the physical and mechanical properties of products, and have better synergy with flame retardants or groups with flame retardant effects , so as to improve the flame retardant performance of the product, expand the tolerance of the formula, and be used in automobiles, trains, aircraft manufacturing, furniture industries and other fields.

The polyaddition reaction of polyisocyanates and polyamines in polyols was first studied by Mueller of Bayer AG in 1963. Since the introduction of polyurea polyol products in the 1970s, its development has been relatively rapid. U.S. Patent 4,107,102 discloses the preparation of polyurethane foam by mixing hydrazine and polyisocyanate in polyols, but does not prepare polyurea polyols in advance; U.S. Patent 3,294,751 discloses The preparation of urea-based polyols by the reaction of alkanolamines and isocyanates is proposed, but no polyols are used as the medium; British Patent 2,098,229 discloses the preparation of polyurea polyols by the reaction of alkanolamines with isocyanates under the action of a catalyst, but the system contains some Hydroxyl reacts with isocyanate to form urethane, with low graft solid content and high viscosity of the resulting product; US Patent No. 4,293,470 discloses the use of an amine compound as a cooling curing agent to improve the storage stability of polyurea polyols.

Due to the generation of a large number of urea bonds during the synthesis of polyurea polyols, it is easy to aggregate to form large particles, and it is easy to form hydrogen bond compounds with small molecules of water, which affects the viscosity and stability of the system and inhibits its development. In the reported patent And in the literature, the equipment investment of laboratory dripping method is less, but the polyurea polyol solid content of preparation is generally 10%, and viscosity is above 10000mPa s/25 ℃ (German patent 1,260,142), and viscosity is too high; The solid content is generally 20%. US Patent No. 4,089,835 discloses the continuous production of polyurea polyol with a solid content of 10%. The viscosity is about 2500mPa·s/25°C, but the equipment investment of the continuous process is large.

(3) Contents of the invention

The object of the present invention is to provide a preparation method of polyurea polyol in order to solve the above-mentioned deficiencies in the prior art. The method adds a solvent to the reaction system to dilute and lubricate, improve the particle size distribution and particle shape of polyurea particles, inhibit the hydrogen bonding of water in the system, and form a low-boiling azeotrope with water, and It is more conducive to the vacuum removal of water in the later stage of the reaction, so as to reduce the viscosity of the product and improve the storage stability of the product.

The preparation method of a polyurea polyol according to the present invention is characterized in that it includes the following operating steps and process conditions: firstly mix polyether polyol, polyamine and solvent, add isocyanate or isocyanate and polyether under stirring The mixture of polyols can be vacuum removed after the reaction.

In order to realize the present invention better, described isocyanate is aliphatic and aromatic polyisocyanate, comprises m-phenylene diisocyanate, p-phenylene diisocyanate, polymethyl polyphenyl polyisocyanate, 2,4-toluene diisocyanate, 2 , 6-toluene diisocyanate, naphthalene diisocyanate, diphenylmethane 4,4'-diisocyanate, diphenylmethane 2,4-diisocyanate, diphenylmethane 2,2'-diisocyanate, hexamethylene Diisocyanates and mixtures of two or more of the above. Commonly used is a mixture of 2,4- and 2,6-toluene diisocyanate TDI (mass ratio of 80/20). The hydroxyl value of the polyether polyol is generally between 20 and 60, the functional group is between 2 and 4, the molecular weight is between 2000 and 8000, and it is advisable to have more primary hydroxyl groups; Highly active polyether polyol with a hydroxyl content of about 80% and a molecular weight of 5,000. The polyamines are aliphatic, alicyclic and aromatic compounds with primary or secondary amino groups and their hydrates, including ethylenediamine, hexamethylenediamine, 1,2-propylenediamine, 1,3 -Propylenediamine, tetramethylenediamine, piperazine hydrate, hydrazine hydrate, N, N'-substituted hydrazine, hydrazine, and mixtures of two or more of the above, the molecular weight of these compounds is generally between 32 and 1000 , commonly used in industry is hydrazine hydrate. The solvents are polar and non-polar solvents, including benzene, toluene, xylene, gasoline, and mixtures of two or more of the above, and toluene is commonly used.

During the synthesis of polyurea polyols, there are competing reactions between polyols and isocyanates, and between polyamines and isocyanates. Controlling the degree of reaction between the two competing reactions is crucial to the quality of the finished product. The stability of the dispersion is obtained by the participation of those polyols as the dispersion medium in the reaction to form the polyurea polymer. If the reaction between polyamine and isocyanate is too large, the polyurea particles will become larger and easy to precipitate. The reaction between polyol and isocyanate is too large, and the formation of cross-linked carbamate increases the viscosity of the system, and even local agglomeration occurs. While high-solids PHD products are limited by high viscosity, the extent to which polyols participate in the reaction depends on the relative reactivity of isocyanates relative to polyols and polyamines. Therefore, when many documents and patents control the degree of participation of polyols in the reaction, most of them use water during the synthesis and then remove it in a vacuum. Water can affect the reaction in many ways, especially the effective stoichiometry of the reaction. The presence of some amines in water is more conducive to the reaction of polyol hydroxyl groups. But there is also such a problem at the same time, that is, water will form a hydrogen bond compound with urea bond to increase the viscosity of the system, and it is not conducive to vacuum removal. The present invention provides a more effective method, that is, adding a solvent to inhibit water in the system The hydrogen bond in the reaction forms a low-boiling azeotrope, which is more conducive to the vacuum removal after the reaction. When adopting the industrial continuous method to implement the present invention, part polyether polyol, polyamine and solvent mixture can be used as a reaction stream, another reaction stream is made up of the mixture of isocyanate and polyether polyol, two reaction streams pass through mechanical pump or The high-pressure device is transported to the reaction kettle, and it is mixed evenly by high-speed stirring. The reaction is carried out quickly and it flows out from the discharge port, and it can be stored in vacuum degassing.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

1. The present invention adds an appropriate amount of solvent to the reaction system. The benefits of using the solvent include: 1) reducing the overall viscosity of the reaction system in the reactor, which is conducive to the full reaction of polyamines and isocyanates; 2) improving the dispersion of polyurea particles generated Through the plasticizing mechanism, the particles tend to form a smooth spherical shape, and the particle aggregates are reduced, so as to achieve the purpose of reducing the viscosity of the product; 3) Because water is easy to form hydrogen bonds with urea bonds, it is dehydrated after post-treatment During the process, the solvent and water form a low-boiling azeotrope, which is conducive to the detachment of water, thereby reducing the impact of water on the viscosity of the product.

2. The polyurethane foam is prepared by reacting the polyurea polyol prepared in the present invention with a diisocyanate compound, and the polyurethane foam has high load-carrying capacity and good flame retardancy (up to self-extinguishing level).

3. The polyurea polyol prepared by the present invention is suitable for the field of polyurethane, especially for the field of polyurethane foam.

(4) Specific implementation methods

The present invention will be described in further detail below in conjunction with the embodiments.

Embodiment one

Add 360g polyether polyol (domestic 330N) and 11.1g hydrazine hydrate (80% hydrazine hydrate content) to a four-necked flask equipped with a thermometer, condensing reflux pipe, nitrogen conduit, dropping funnel and mechanical stirring, and replace with nitrogen Air in the bottle for 10 minutes, then close the system, and stir the premixed base material at high speed for 10 minutes. And under vigorous stirring, 34.3g TDI (80/20) was gradually added dropwise into the polyol/polyamine system. Control the temperature at about 40±2°C, continue to react for 0.5 to 1 hour after adding the isocyanate, and then vacuumize for 2.5 to 3 hours at a temperature lower than -0.095MPa and 120±5°C to remove water and residual monomers. body, the milky white polyurea polyol product with a solid content of 10%, a viscosity of 8300mPa·s/25°C and relatively coarse particles can be obtained.

Embodiment two

Add 360g polyether polyol (domestic 330N), 11.1g hydrazine hydrate (hydrazine hydrate content is 80%) and 10g toluene ( Analytical purity), replace the air in the bottle with nitrogen for 10 minutes, then close the system, and stir the premixed bottom material at high speed for 10 minutes. And under vigorous stirring, 34.3g TDI (80/20) was gradually added dropwise into the polyol/polyamine/solvent system. Control the temperature at around 40±2°C, continue to react for 0.5 to 1 hour after adding the isocyanate, and then vacuumize for 2.5 to 3 hours at a temperature lower than -0.095MPa and 120±5°C to remove solvent, water and Residual monomers can be obtained as a milky white polyurea polyol product with a solid content of 10%, a viscosity of 5850mPa·s/25°C, and uniform particle dispersion.

Embodiment Three

Add 340g polyether polyol (domestic 330N), 16.8g hydrazine hydrate (hydrazine hydrate content is 80%) and 15g toluene ( Analytical purity), replace the air in the bottle with nitrogen for 10 minutes, then close the system, and stir the premixed bottom material at high speed for 10 minutes. And under vigorous stirring, 51.4g of TDI (80/20) was gradually added dropwise into the polyol/polyamine/solvent system. Control the temperature at around 40±2°C, continue to react for 0.5 to 1 hour after adding the isocyanate, and then vacuumize for 2.5 to 3 hours at a temperature lower than -0.095MPa and 120±5°C to remove solvent, water and Residual monomers can be obtained as a milky white polyurea polyol product with a solid content of 15%, a viscosity of 11500mPa·s/25°C, and uniform particle dispersion.

Embodiment four

Add 360g polyether polyol (domestic 330N) and 14g piperazine hexahydrate into a four-neck flask equipped with a thermometer, condensing reflux tube, nitrogen conduit, dropping funnel and mechanical stirring, replace the air in the bottle with nitrogen for 10 minutes, and then Close the system and stir the premixed base material at high speed for 10 minutes. And under vigorous stirring, 27.6g of TDI (80/20) was gradually added dropwise into the polyol/polyamine system, and the reaction temperature was controlled at 55±5°C. After adding the isocyanate, continue to react for 0.5 to 1 hour, and then vacuumize for 2.5 to 3 hours at a temperature lower than -0.095MPa and 120±5°C to remove water and residual monomers to obtain a solid content of 10 %, a milky white polyurea polyol product with a viscosity of 3800mPa·s/25°C and large particles.

Embodiment five

Add 360g of polyether polyol (domestic 330N), 14g of piperazine hexahydrate and 15g of toluene (analytical pure) into a four-necked flask equipped with a thermometer, condensing reflux tube, nitrogen conduit, dropping funnel and mechanical stirring, and replace with nitrogen Air in the bottle for 10 minutes, then close the system, stir the premixed base material at high speed for 10 minutes, and gradually add 27.6g TDI (80/20) dropwise to the polyol/polyamine/solvent system under vigorous stirring, and control the reaction temperature at 55±5°C. After adding the isocyanate, continue to react for 0.5 to 1 hour, and then vacuumize for 2.5 to 3 hours at a temperature lower than -0.095MPa and 120±5°C to remove solvent, water and residual monomers to obtain the solid content Milky white polyurea polyol product with a viscosity of 10% and a viscosity of 2900mPa·s/25°C with uniform particles.

Claims (5)

1. the preparation method of a polyurea polylol, it is characterized in that, it comprises following operation steps and processing condition: at first with polyether glycol, polyamine and solvent, under agitation add the mixture of isocyanic ester or isocyanic ester and polyvalent alcohol, the reaction final vacuum removes and gets final product.

2. the preparation method of a kind of polyurea polylol according to claim 1, it is characterized in that, described isocyanic ester is aliphatics and aromatic polyisocyanate, comprise m-benzene diisocyanate, PPDI, polymethine polyphenyl polyisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, naphthalene diisocyanate, ditan 4,4 '-vulcabond, ditan 2,4-vulcabond, ditan 2,2 '-vulcabond, hexamethylene-diisocyanate and above-mentioned two or more mixture.

3. the preparation method of a kind of polyurea polylol according to claim 1 is characterized in that, the hydroxyl value of described polyether glycol is between 20～60, and functional group is that molecular weight is between 2000～8000 between 2～4.

4. the preparation method of a kind of polyurea polylol according to claim 1, it is characterized in that, described polyamine is aliphatics, alicyclic and the compound of aromatic series band primary amine groups or secondary amine and their hydrate, comprise quadrol, hexanediamine, 1,2-Pn, 1,3-Pn, tetramethylene-diamine, Piperzine Hexahydrate, hydrazine hydrate, N, N '-replacement hydrazine, hydrazine acyl and above-mentioned two or more mixture.

5. the preparation method of a kind of polyurea polylol according to claim 1 is characterized in that, described solvent is polarity and non-polar solvent, comprises benzene,toluene,xylene, gasoline and above-mentioned two or more mixture.