Method for solvent-free production of flexibilizer bisphenol A polyether for coating

Abstract

The invention discloses a method for solvent-free production of a flexibilizer bisphenol A polyether for coating, which comprises the following steps: (1) mixing bisphenol A and a catalyst in a reaction container, carrying out vacuum nitrogen displacement on the reaction container, adding a bulk polymerization monomer, heating and stirring for dissolving and mixing until the pressure in the reaction container is stable to obtain an initiator; (2) filling nitrogen into the reaction container, adding a bulk polymerization monomer to be mixed with an initiator, heating, stirring and carrying out polymerization reaction until the pressure in the reaction container is stable, and carrying out heat preservation and degassing to obtain a crude polyether product; (3) cooling, adding water into the reaction container, carrying out heat preservation emulsification, adding a neutralizer, and heating to carry out a neutralization reaction; (4) heating and dehydrating, continuously filling nitrogen into the reaction container, adding a refining agent for dehydrating, and filtering out solid residues to obtain the flexibilizer bisphenol A polyether, the bisphenol A polyether prepared by the method is uniform in molecular weight distribution and light in product color, and can completely meet the performance requirements in the aspect of coatings.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical coatings, and particularly relates to a method for producing bisphenol A polyether, a toughening agent for coatings, without solvent. Background Art

[0002] Electrophoretic coating technology is a coating process based on the requirements for corrosion and rust prevention of metal surfaces and high surface finish. The base bisphenol A epoxy resin commonly used in cathodic electrophoretic coatings used in the automotive industry is generally a hard and brittle polymer with high strength. This base has poor flexibility, so it is easy to produce cracks on the surface of the coating layer and defects such as poor finish. With the continuous development of the automotive industry, the requirements for material performance are constantly improving, and higher requirements are also placed on the performance of the coating film. A suitable toughening agent is needed to make up for the toughness defects of the coating film. Bisphenol A polyether toughening agent has both cost and performance advantages, is more conducive to large-scale production and wide application, and is one of the best choices for epoxy resin toughening agents.

[0003] The production of bisphenol A polyether generally adopts the process of ring-opening polymerization of ethylene oxide under anionic catalysis. However, due to the high melting point of bisphenol A, the temperature of the polymerization reaction is very high, which causes ethylene oxide to participate in the polymerization reaction under high reactivity. Therefore, the prepared product has a darker color. In addition, the side reaction products and ethylene oxide self-polymers caused by high temperature will also lead to uneven molecular weight distribution, further reducing the performance of the product, resulting in its inability to meet the requirements of existing coatings in some performance aspects. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a method for producing bisphenol A polyether, a toughening agent for coatings, without solvent. The bisphenol A polyether prepared by the method has a uniform molecular weight distribution and a light product color, which can fully meet the performance requirements of coatings.

[0005] The above technical objectives of the present invention are achieved through the following technical solutions:

[0006] A method for producing bisphenol A polyether, a toughening agent for coatings, without solvent, comprises the following steps: (1) mixing bisphenol A and a catalyst in a reaction container, replacing the reaction container with nitrogen in vacuum, adding a bulk polymerization monomer once, heating and stirring to dissolve and mix until the pressure in the reaction container is stable, and obtaining an initiator; (2) filling the reaction container with nitrogen and then adding a bulk polymerization monomer for a second time to mix with the initiator, heating and stirring to react with the polymerization until the pressure in the reaction container is stable, and heat-insulating and degassing to obtain a crude polyether product; (3) cooling and adding water to the reaction container, heat-insulating and emulsifying, adding a neutralizing agent, and then heating and conducting a neutralization reaction; (4) heating and conducting a primary dehydration, continuously filling the reaction container with nitrogen and adding a refining agent to conduct a secondary dehydration, filtering out solid residues, and obtaining the toughening agent bisphenol A polyether.

[0007] Preferably, in step (1), the catalyst is at least one of Na, K, Na2O, K2O, NaOH aqueous solution, KOH aqueous solution, sodium alcoholate, potassium alcoholate, alcoholamine and aromatic amine.

[0008] Further preferably, in step (1), the catalyst is an aqueous solution of NaOH or KOH with a mass concentration of 25%-85%.

[0009] Further preferably, in step (1), the catalyst is a NaOH or KOH aqueous solution with a mass concentration of 45%-55%.

[0010] Preferably, in step (1), the amount of the catalyst used is 0.05%-0.50% of the total mass of the theoretically produced polyether calculated as NaOH.

[0011] Further preferably, in step (1), the amount of the catalyst used is 0.10%-0.20% of the total mass of the theoretically produced polyether calculated as NaOH.

[0012] Preferably, in step (1), the dissolution temperature is 50-110° C., and the dissolution time is 0.5-2 h.

[0013] Further preferably, in step (1), the dissolution temperature is 65-75°C, and the dissolution time is 1-1.5h.

[0014] Preferably, the reaction vessel is a high-pressure polymerization reactor.

[0015] Preferably, in step (1), the bulk polymerization monomer is at least one of ethylene oxide and propylene oxide.

[0016] Preferably, in step (1), the amount of the bulk polymerization monomer added is 5%-10% of the mass of the bisphenol A.

[0017] Preferably, in steps (1) and (2), the molar ratio of the sum of the bulk polymerization monomer added once and the bulk polymerization monomer added twice to the bisphenol A is (2-60):1.

[0018] Further preferably, in steps (1) and (2), the molar ratio of the sum of the bulk polymerization monomer added once and the bulk polymerization monomer added twice to the bisphenol A is (4-8):1.

[0019] Preferably, in step (2), the secondary addition of bulk polymerization monomers takes place over a period of 2-5 hours.

[0020] Preferably, in step (2), the polymerization reaction temperature is 65-135° C., the polymerization reaction time is 1-6 h, and the polymerization reaction pressure is not higher than 0.60 MPa.

[0021] Further preferably, in step (2), the polymerization reaction temperature is 90-115° C., the polymerization reaction time is 3-4 h, and the polymerization reaction pressure is not higher than 0.45 MPa.

[0022] Preferably, in step (2), the time of heat preservation and degassing is 20-60 minutes.

[0023] Preferably, in step (3), the mass of water added is 5%-25% of the total amount of the reaction system.

[0024] Further preferably, in step (3), the mass of water added is 8%-15% of the total amount of the reaction system.

[0025] Preferably, in step (3), the temperature of the heat preservation emulsification is 75-110° C., and the time of the heat preservation emulsification is 0.5-2 h.

[0026] Preferably, in step (3), the neutralizing agent is at least one of phosphoric acid, sulfuric acid, hydrochloric acid, oxalic acid and adipic acid.

[0027] Preferably, in step (3), the mass of the neutralizing agent added is 0.1%-1.0% of the total mass of the theoretically produced polyether.

[0028] Preferably, in step (3), the temperature of the neutralization reaction is 75-110° C., and the time of the neutralization reaction is 0.5-2 h.

[0029] Further preferably, in step (3), the temperature of the neutralization reaction is 105-110° C., and the time of the neutralization reaction is 0.5-1 h.

[0030] Preferably, in step (4), the temperature of the primary dehydration is 100-130° C., the time of the primary dehydration is 1-2 h, and the method of the primary dehydration is vacuum pumping.

[0031] Preferably, in step (4), the refining agent is at least one of magnesium silicate or aluminum silicate.

[0032] Preferably, in step (4), the amount of the refining agent added is 0.1%-0.5% of the total mass of the theoretically produced polyether.

[0033] Preferably, in step (4), during the secondary dehydration, the temperature of the primary dehydration is maintained and bubbling dehydration is performed at the bottom of the container for 2-5 hours, and the refining is considered completed when the water content in the container is less than 0.05%.

[0034] Preferably, in step (4), the filtration may be performed using various types of filters, the purpose of which is to remove the salts in the polyether and the solid residue formed by the refining agent.

[0035] The beneficial effects of the present invention are:

[0036] The invention has the advantages that no impurities brought by solvents are generated in the preparation process of bisphenol A polyether, the occurrence of side reactions can be effectively reduced, and there is no step of removing solvents. At the same time, bulk polymerization monomers are firstly used to dissolve polymerized bisphenol A at low temperature to form an initiator containing a catalyst, and then a quantitative amount of ethylene oxide is introduced into the initiator under certain temperature and pressure conditions to carry out polymerization reaction. By controlling the activity of the polyether reaction, the produced bisphenol A polyether product has high purity, more uniform molecular weight distribution, and lighter product color, and can fully meet the performance requirements of coatings. DETAILED DESCRIPTION

[0037] The present invention will be further described below in conjunction with specific embodiments.

[0038] Embodiment 1:

[0039] A method for producing bisphenol A polyether, a toughening agent for coatings, without solvent, comprises the following steps:

[0040] (1) In a 10L autoclave, 20g of a 45% NaOH aqueous solution and 2317g of bisphenol A were added in sequence, and after vacuum nitrogen replacement, 215g of ethylene oxide was added, and stirring was started at 65°C to mix and dissolve for 1 hour until the pressure stabilized to obtain an initiator;

[0041] (2) nitrogen was added until the pressure in the autoclave was slightly higher than normal pressure, 2468 g of ethylene oxide was slowly added to the initiator, the feeding time was controlled to be 4 hours, the reaction temperature was controlled to be 90° C., at which time the pressure in the autoclave was not higher than 0.45 MPa, the reaction temperature was maintained for 1 hour until the pressure in the autoclave no longer decreased, and the temperature was maintained for degassing for 30 minutes;

[0042] (3) Cooling to 75°C, adding 500 g of water, maintaining the temperature for emulsification for 30 minutes, adding 30 g of 85% phosphoric acid, and heating to 105°C for neutralization for 1 hour;

[0043] (4) heating to 110° C. for dehydration for 2 hours, turning off the vacuum, breaking the vacuum in the reactor with nitrogen, adding 15 g of magnesium silicate, bubbling with nitrogen and continuing to dehydrate for 2 hours until the water content in the autoclave is less than 0.05%;

[0044] (5) The solid residue in the system is filtered to obtain about 5000 g of a light yellow transparent bisphenol A polyether product.

[0045] Embodiment 2:

[0046] A method for producing bisphenol A polyether, a toughening agent for coatings, without solvent, comprises the following steps:

[0047] (1) In a 10L autoclave, 20g of a 55% NaOH aqueous solution and 2317g of bisphenol A were added in sequence, and after vacuum nitrogen replacement, 215g of ethylene oxide was added, and stirring was started to mix and dissolve at 75°C for 1 hour until the pressure stabilized to obtain an initiator;

[0048] (2) nitrogen was added until the pressure in the autoclave was slightly higher than normal pressure, 2468 g of ethylene oxide was slowly added to the initiator, the feeding time was controlled to 3 hours, the reaction temperature was controlled to 115° C., at which time the pressure in the autoclave was not higher than 0.45 MPa, the reaction temperature was maintained for 1 hour until the pressure in the autoclave no longer decreased, and the temperature was maintained for degassing for 40 minutes;

[0049] (3) Cooling to 100°C, adding 500 g of water, maintaining the temperature for emulsification for 60 minutes, adding 30 g of 85% phosphoric acid, and heating to 110°C for neutralization for 0.5 hour;

[0050] (4) heating to 130° C. for dehydration for 1 hour, turning off the vacuum, breaking the vacuum in the reactor with nitrogen, adding 15 g of magnesium silicate, bubbling with nitrogen and continuing dehydration for 3 hours until the water content in the autoclave is less than 0.05%;

[0051] (5) The solid residue in the system is filtered to obtain about 5000 g of a light yellow transparent bisphenol A polyether product.

[0052] Embodiment 3:

[0053] A method for producing bisphenol A polyether, a toughening agent for coatings, without solvent, comprises the following steps:

[0054] (1) In a 10L autoclave, 20g of a 50% NaOH aqueous solution and 2317g of bisphenol A were added in sequence, and after vacuum nitrogen replacement, 215g of ethylene oxide was added, and stirring was started to mix and dissolve at 70°C for 1 hour until the pressure stabilized to obtain an initiator;

[0055] (2) nitrogen was added until the pressure in the autoclave was slightly higher than normal pressure, 2468 g of ethylene oxide was slowly added to the initiator, the feeding time was controlled to be 4 hours, the reaction temperature was controlled to be 110° C., at this time, the pressure in the autoclave was not higher than 0.45 MPa, the reaction temperature was maintained for 1 hour until the pressure in the autoclave no longer decreased, and the temperature was maintained for degassing for 30 minutes;

[0056] (3) Cooling to 90°C, adding 500 g of water, maintaining the temperature for emulsification for 60 minutes, adding 30 g of 85% phosphoric acid, and heating to 105°C for neutralization for 0.5 hour;

[0057] (4) heating to 115° C. for dehydration for 1 hour, turning off the vacuum, breaking the vacuum in the reactor with nitrogen, adding 15 g of magnesium silicate, bubbling with nitrogen and continuing to dehydrate for 2 hours until the water content in the autoclave is less than 0.05%;

[0058] (5) The solid residue in the system is filtered to obtain about 5000 g of a light yellow transparent bisphenol A polyether product.

[0059] Test example:

[0060] The bisphenol A polyether products prepared in Examples 1-3 were tested for performance according to relevant standards and indicators of coatings. The results are shown in Table 1.

[0061] Table 1. Performance test results

[0062]

[0063]

[0064] It can be seen from Table 1 that the bisphenol A polyether prepared in the present invention meets the relevant standards for coatings.

[0065] The bisphenol A polyether products prepared in Examples 1-3 were respectively subjected to performance tests according to relevant standards and indicators of coating films prepared according to the same formula. The results are shown in Table 2.

[0066] Table 2. Paint film performance test results

[0067] Paint film properties Example 1 Example 2 Example 3 Appearance Flat and smooth Flat and smooth Flat and smooth Thickness / μm 25 24 24 luster 65 70 80 hardness 4H 3H 3H Impact resistance / cm 70 80 100 Flexibility / mm 1 1 1 Cross-cut / ≤mm 1 1 1 MEK resistance / times 130 125 125 Cupping / mm 8.0 8.2 8.4 Salt spray resistance / h 900 980 950

[0068] As can be seen from Table 2, the paint film prepared from the bisphenol A polyether prepared in the present invention has excellent paint film properties. The hardness of the prepared paint film can reach 3H, the impact resistance can reach 70cm, the flexibility can reach 1mm, the cross-cutting can reach 1mm, the MEK (methyl ethyl ketone) wiping resistance can reach 125 times, the cupping can reach 8.0mm, and the salt spray resistance can reach 900h.

[0069] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for producing bisphenol A polyether as a toughening agent for coatings without solvent, characterized in that: The following steps are involved: (1) mixing bisphenol A and a catalyst in a reaction container, replacing the reaction container with vacuum nitrogen, adding bulk polymerization monomers at once, heating and stirring to dissolve and mix until the pressure in the reaction container is stable, to obtain an initiator; (2) filling the reaction container with nitrogen, adding bulk polymerization monomers for a second time and mixing with the initiator, heating and stirring the polymerization reaction until the pressure in the reaction container is stable, and heat-insulating and degassing to obtain a crude polyether product; (3) After cooling, water is added to the reaction container, and after heat preservation and emulsification, a neutralizing agent is added and the temperature is raised to carry out a neutralization reaction; (4) heating and performing a primary dehydration, continuously filling nitrogen into the reaction container and adding a refining agent for secondary dehydration, filtering out solid residues, and obtaining the toughening agent bisphenol A polyether.

2. The method for producing bisphenol A polyether as a toughening agent for coatings without solvent according to claim 1, characterized in that: In step (1), the catalyst is at least one of Na, K, Na2O, K2O, NaOH aqueous solution, KOH aqueous solution, sodium alcoholate, potassium alcoholate, alcoholamine and aromatic amine.

3. The method for producing bisphenol A polyether as a toughening agent for coatings without solvent according to claim 1, characterized in that: In step (1), the dissolution temperature is 50-110° C., and the dissolution time is 0.5-2 h.

4. The method for producing bisphenol A polyether as a toughening agent for coatings without solvent according to claim 1, characterized in that: In step (1), the bulk polymerization monomer is at least one of ethylene oxide and propylene oxide.

5. The method for producing bisphenol A polyether as a toughening agent for coatings without solvent according to claim 1, characterized in that: In step (2), the feeding time of the secondary addition of bulk polymerization monomer is 2-5 hours.

6. The method for producing bisphenol A polyether as a toughening agent for coatings without solvent according to claim 1, characterized in that: In step (2), the polymerization reaction temperature is 65-135° C., the polymerization reaction time is 1-6 h, and the polymerization reaction pressure is not higher than 0.60 MPa.

7. The method for producing bisphenol A polyether as a toughening agent for coatings without solvent according to claim 1, characterized in that: In step (3), the temperature of the heat preservation emulsification is 75-110° C., and the time of the heat preservation emulsification is 0.5-2 h.

8. The method for producing bisphenol A polyether as a toughening agent for coatings without solvent according to claim 1, characterized in that: In step (3), the temperature of the neutralization reaction is 75-110° C., and the time of the neutralization reaction is 0.5-2 h.

9. The method for producing bisphenol A polyether as a toughening agent for coatings without solvent according to claim 1, characterized in that: In step (4), the temperature of the primary dehydration is 100-130° C., and the time of the primary dehydration is 1-2 h.

10. The method for producing bisphenol A polyether as a toughening agent for coatings without solvent according to claim 1, characterized in that: In step (4), the secondary dehydration is carried out by bubbling and dehydrating at the bottom of the container for 2-5 hours while maintaining the temperature of the primary dehydration. The refining is considered to be completed when the water content in the container is less than 0.05%.

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