WO2020041921A1

WO2020041921A1 - Process for preparing hexamethoxymethyl melamine resin rubber adhesive

Info

Publication number: WO2020041921A1
Application number: PCT/CN2018/102420
Authority: WO
Inventors: 胡立新; 宗红兴; 郎旭东; 谈建新
Original assignee: 江苏国立化工科技有限公司
Priority date: 2018-08-27
Filing date: 2018-08-27
Publication date: 2020-03-05

Abstract

Disclosed is a process for preparing a hexamethoxymethyl melamine resin rubber adhesive, comprising S1: feeding methanol into an etherification kettle, and stirring same; and then adding a hexahydroxy resin and continuously stirring same; S2: adding sulfuric acid into the etherification kettle and subjecting same to an etherification reaction, and continuously reacting same after the material has become clear; S3: adding a sodium hydroxide solution into the solution obtained in S2 and subjecting same to a neutralization reaction, and measuring the pH of the solution after the reaction; S4: recovering the methanol from the mixed solution; S5: subjecting a distillation kettle to a heating treatment and then recovering same under reduced pressure until there is no distillate in an inspection cylinder; and S6: subjecting same to suction filtering under vacuum, and obtaining a clear liquid as the finished product. The prepared rubber adhesive has a high adhesive strength and stable properties, and can be widely applied.

Description

[Name of invention formulated by ISA according to Rule 37.2] Preparation process of hexamethoxymethyl melamine resin rubber adhesive

Technical field

The invention relates to the technical field of engineering materials, in particular to a process for preparing a hexamethoxymethylmelamine resin rubber adhesive.

Background technique

In the rubber industry, adhesion refers to the combination of the contact between rubber and the surface of homogeneous or heterogeneous materials by the physical action of van der Waals force or the chemical action of bonding force. Generally, a substance capable of joining adjacent surfaces of a material is called an adhesive. Rubber adhesive is a mixture composed of highly active organic amine compounds and inorganic substances containing a large number of active groups. It can be added to rubber products with fiber cords as the skeleton material. It acts as a bridge between rubber and cord, producing a strong chemical bond, improving the bonding strength, and improving the rubber coverage of the cord. At present, rubber adhesives have been widely used in self-adhesion and mutual adhesion between materials such as conveyor belts, rubber, leather, metals, and ceramics.

However, the rubber adhesive used in the prior art is usually a single combination of rubber and solvent. Therefore, in bonding rubber products, especially in the process of bonding different rubber products, it often leads to weak bonding and easy Looseness and other phenomena make the bonding effect poor and the product quality is greatly affected. Therefore, providing a rubber adhesive preparation process with good bonding performance and strong practicability is a problem to be urgently solved by the present invention.

Summary of the Invention

Aiming at the above-mentioned prior art, the object of the present invention is to overcome the problems of inadequate adhesion of existing rubber adhesives, easy loosening, and poor quality of the rubber products produced, and to provide a hexamethoxymethylmelamine resin rubber adhesive. Agent preparation process.

The technical solution of the present invention is: a process for preparing a hexamethoxymethyl melamine resin rubber adhesive, which is characterized in that it mainly includes the following steps:

S1: Feeding

Put the methanol into the etherification kettle with a beater and stir. Then add hexahydroxy to the etherification kettle and continue stirring. Among them, methanol and hexahydroxy are added twice. First, add a portion of methanol to the etherification kettle, and then Add a portion of hexahydroxy to the etherification kettle, stir for the first time, then put the remaining methanol and hexahydroxy into the mixture, and stir for the second time; during the first stirring process, add catalyst to the etherification kettle; The dosage is 8000-10000Kg, and the amount of hexahydroxy is 4000-5000Kg. First, add 4000-5000Kg of methanol to the etherification kettle, and then add 2000-2500Kg of hexahydroxy to the etherification kettle, and perform the first stirring. , The first stirring speed is 500RPM, the first stirring temperature is 25 ° C, and the first stirring time is 20min; then the remaining methanol and hexahydroxyl are separately added to the etherification kettle, and the second stirring is performed, the second stirring The stirring speed is 300RPM, the second stirring temperature is 20 ° C, and the second stirring time is 10min;

S2: etherification

After the feeding, the etherification kettle was heated to 48 ° C-58 ° C and subjected to heat preservation treatment. Sulfuric acid was added to the etherification kettle to adjust the pH. The pH was measured every 5 minutes after the addition of sulfuric acid, and the last measurement was pH = 2- 3; Then add a catalyst to the solution and stir, and carry out the reaction at a temperature of 48 ° C-58 ° C. After the material becomes clear, continue the reaction for 60-120 minutes;

S3: Neutralize

After the etherification reaction is completed, when the temperature is 48 ° C-58 ° C, a sodium hydroxide solution is added to the solution obtained in S2 to neutralize the reaction. After the addition, the pH value is measured once every 5 minutes, three times, and the last time pH = 8-9; standby

S4: Recovery of methanol

1) The hexamethoxymethyl melamine resin rubber binder mixed solution containing a methanol solution is pumped into a heat exchanger by a pump, and the hexamethoxymethyl discharged from the bottom of the distillation kettle is heated in the heat exchanger. Melamine resin rubber binder mixture for preliminary heat exchange;

2) The hexamethoxymethyl melamine resin rubber binder mixed solution containing the methanol solution after preliminary heat exchange enters the top of the distillation kettle, and the methanol mixture flashed after the reboiler is heated is sprayed on the top of the distillation kettle. The mixed solution containing the hexamethoxymethyl melamine resin rubber adhesive was subjected to reverse contact heat exchange, and the methanol content in the hexamethoxymethyl melamine resin rubber adhesive solution discharged from the top of the distillation kettle was zero;

3) The mixture of hexamethoxymethyl melamine resin rubber adhesive and methanol overflowing from the top of the distillation kettle is cooled by a cooling tower. After cooling, the methanol and hexamethoxymethyl melamine resin rubber adhesive are all condensed. Part of the reflux liquid enters the bottom of the distillation kettle;

4) The condensate overflowing from the bottom of the primary cooling tower and the secondary cooling tower enters the bottom of the distillation kettle under the action of pressure difference and pressure difference, and the gas phase hexamethoxymethylmelamine resin rubber adhesive enters the etherification at the same time. The top of the kettle is contacted to produce formaldehyde in the distillation kettle, the pressure of the distillation kettle is 90-110KPa, and the temperature of the bottom of the distillation kettle is 95 ° C;

S5: Distillation

The distillation kettle is heated up. When the temperature reaches 75-85 ° C, it is recovered under reduced pressure. When the vacuum is 0.08-0.1Mpa and the temperature is 125 ° -135 ° C, the steam is turned off, the heating is stopped, and the vacuum is continued for 60-120min. The temperature is 125 ° C-140 ° C, and the vacuum is released until there is no distillate in the tube.

S6: suction filtration

Use a suction pump to pump the solution obtained from S5 into a vacuum suction filtration device to start suction filtration. After the suction filtration is dried, rinse the residue on the filter membrane with 0.8% citric acid ethanol solution, and then wash and dry with deionized water. Liquid is the finished product.

Further, in step S1, the dosage of methanol is 8000-10000Kg and the dosage of hexahydroxy is 4000-5000Kg; firstly, 4000-5000Kg of methanol is added to the etherification kettle, and then 2000-5000 is added to the etherification kettle. 2500Kg of hexahydroxy, first stirring, the first stirring speed is 500RPM, the first stirring temperature is 25 ° C, and the first stirring time is 20min; then the remaining methanol and hexahydroxy are separately added to the etherification kettle , The second stirring, the second stirring speed is 300 RPM, the second stirring temperature is 20 ° C, the second stirring time is 10 minutes; control the stirring speed, temperature, time, so that methanol and hexahydroxy are fully mixed, so that the material The response was thorough.

Further, in step S1, the catalyst is a triethylamine, diisobutylaluminum hydride, chloropropane, isopropanol composite catalyst, and the ratio of triethylamine, diisobutylaluminum hydride, and chloropropane (mol / mol / mol / mol) is 1.2: 4.5: 0.2: 0.1; Triethylamine, diisobutylaluminum hydride, chloropropane, and isopropanol are sequentially added to the preparation kettle, and the temperature of the preparation kettle is controlled at 0-8 ° C, and stirred 40-55min, the product obtained is the finished product of the catalyst; the catalyst prepared by this method has good catalytic effect, and has a wide temperature range, and has no effect on the heat transfer efficiency and working efficiency of the etherification kettle To ensure the safety and stability of the system operation.

Further, in step S4, the reboiler uses medium-pressure steam to heat the alcohol-containing hexamethoxymethylmelamine resin rubber binder solution in the etherification kettle, and the top temperature of the distillation kettle is 85-120 ° C, and the bottom temperature is 136-140 ℃, the pressure is normal pressure, the temperature of the gas phase after the first cooling is 10-35 ℃, the temperature of the gas phase after the second cooling is 8-15 ℃, to ensure that the methanol can be completely condensed, the first cooling tower and the second cooling The column pressure is 0.2 MPa, and the reflux liquid obtained at the bottom of the primary cooling tower and the secondary cooling tower contains a small amount of a mixture of methanol and water.

Further, in step S4, the mixed gas of hexamethoxymethyl melamine resin rubber binder and methanol overflowing from the top of the still of the distillation kettle passes through the first-stage cooling tower and the second-stage cooling tower in this order. The methanol and hexamethoxymethyl melamine resin rubber adhesives condense. The uncooled methanol and hexamethoxymethyl melamine resin rubber adhesives enter the secondary cooling tower and continue to condense. After two stages of cooling, the methanol and The hexamethoxymethyl melamine resin rubber adhesive was completely condensed, and a part of the reflux liquid entered the bottom of the distillation kettle.

Further, before performing step S5, add a defoamer to the distillation kettle, the defoamer is composed of the following components: 10-15 parts of hydrocarbonated oil, 8-13 parts of graphene oxide, and 6-8 of composite emulsifier Parts, thickener 0.1-0.3 parts, preservatives 0.1-0.2 parts, deionized water 120-150 parts, the preparation method is to stir and mix the hydrocarbonated oil and graphene oxide; then add composite emulsifier, thickener, Preservative, finally add deionized water slowly, stir and mix well. The amount of defoamer is 0.3% -0.8%; defoamer has a certain emulsification effect, which can reduce the adhesion of hexamethoxymethyl melamine resin rubber. Agent surface tension, inhibit the generation of air bubbles, improve the quality of hexamethoxymethyl melamine resin rubber adhesive, and the defoamer prepared by this method has strong defoaming performance, long-lasting foam suppression, low dosage and stable chemical properties , High temperature resistance, non-volatile and non-toxic characteristics.

Further, in step S6, the pore size of the filter membrane used in the vacuum filtration is 30-50 μm; the impurities in the hexamethoxymethylmelamine resin rubber filter are filtered to obtain a higher quality hexamethoxymethylmelamine Resin rubber adhesive.

Compared with the prior art, the present invention has the following beneficial effects: the preparation process of the present invention is simple, the preparation time is short, and the preparation efficiency of the hexamethoxymethylmelamine resin rubber bonding is effectively improved; and the Rocca prepared by the preparation process provided by the present invention Oxymethyl melamine resin rubber adhesive has high adhesive strength, can still maintain high adhesive strength in high temperature and high humidity environment, stable properties, and is suitable for wide application.

detailed description

Embodiment 1: A process for preparing a hexamethoxymethyl melamine resin rubber adhesive, which is characterized in that it mainly includes the following steps:

S1: Feeding

Put the methanol into the etherification kettle with a beater and stir. Then add hexahydroxy to the etherification kettle and continue stirring. Among them, methanol and hexahydroxy are added twice. First, add a portion of methanol to the etherification kettle, and then Add a portion of hexahydroxy to the etherification kettle, stir for the first time, then put the remaining methanol and hexahydroxy into the mixture, and stir for the second time; during the first stirring process, add catalyst to the etherification kettle; The added amount is 8000Kg, and the added amount of hexahydroxy is 4000Kg. First, add 4000Kg of methanol to the etherification kettle, and then add 2000Kg of hexahydroxy to the etherification kettle, and perform the first stirring at a speed of 500RPM for the first time. , The first stirring temperature is 25 ° C, the first stirring time is 20min; then the remaining methanol and hexahydroxy are added to the etherification kettle, and the second stirring is performed, the second stirring speed is 300RPM, and the second The stirring temperature is 20 ° C, and the second stirring time is 10 minutes. The catalyst is a triethylamine, diisobutylaluminum hydride, chloropropane, isopropanol composite catalyst, triethylamine, diisobutylaluminum hydride, and chloro. The ratio of propane (mol / mol / mol / mol) is 1.2 : 4.5: 0.2: 0.1; Triethylamine, diisobutylaluminum hydride, chloropropane, and isopropanol were added to the preparation kettle in that order. The temperature of the preparation kettle was controlled at 2 ° C, and the mixture was stirred for 40 minutes. Finished catalyst

S2: etherification

After the feeding, the etherification kettle was heated to 48 ° C and subjected to heat preservation treatment. Sulfuric acid was added to the etherification kettle to adjust the pH. After the sulfuric acid was added, the pH was measured every 5 minutes, and the last measurement was pH = 2; The catalyst was added to the mixture and stirred, and the reaction was performed at a temperature of 48 ° C. After the materials became clear, the reaction was continued for 60 minutes;

S3: Neutralize

After the etherification reaction is completed, when the temperature is 48 ° C, a sodium hydroxide solution is added to the solution obtained in S2 for neutralization reaction. After the addition, the pH value is measured once every 5 minutes, three times, and the last time pH = 8; use;

S4: Recovery of methanol

2) The hexamethoxymethyl melamine resin rubber binder mixed solution containing the methanol solution after preliminary heat exchange enters the top of the distillation kettle, and the methanol mixture flashed after the reboiler is heated is sprayed on the top of the distillation kettle. The mixed solution containing the hexamethoxymethyl melamine resin rubber adhesive was subjected to reverse contact heat exchange, and the methanol content in the hexamethoxymethyl melamine resin rubber adhesive solution discharged from the top of the distillation kettle was zero; The boiler uses medium-pressure steam to heat the alcohol-containing hexamethoxymethyl melamine resin rubber binder solution in the etherification kettle. The top temperature of the distillation kettle is 85 ° C, the temperature at the bottom of the tower is 136 ° C, and the pressure is normal pressure. The temperature of the gas phase after cooling is 10 ℃, and the temperature of the gas phase after secondary cooling is 8 ℃, to ensure that methanol can be completely condensed. The pressure of the primary cooling tower and the secondary cooling tower is 0.2MPa, and the primary cooling tower and the secondary cooling tower are both The reflux liquid obtained at the bottom of the column contained a small amount of a mixture of methanol and water;

3) The mixed gas of hexamethoxymethyl melamine resin adhesive and methanol overflowing from the top of the distillation kettle passes through the primary cooling tower and the secondary cooling tower in this order. In the primary cooling tower, part of the methanol and hexamethoxy Methyl melamine resin rubber adhesive condenses, uncooled methanol and hexamethoxymethyl melamine resin rubber adhesive enters the secondary cooling tower to continue condensation. After two stages of cooling, methanol and hexamethoxymethyl The melamine resin rubber adhesive is completely condensed, and a part of the reflux liquid enters the bottom of the distillation kettle;

4) The condensate overflowing from the bottom of the primary cooling tower and the secondary cooling tower enters the bottom of the distillation kettle under the action of pressure difference and pressure difference, and the gas phase hexamethoxymethylmelamine resin rubber adhesive enters the etherification at the same time. The top of the kettle is contacted in a distillation kettle to produce formaldehyde. The pressure of the distillation kettle is 90KPa and the temperature of the bottom of the distillation kettle is 95 ° C.

S5: Distillation

Add defoamer to the distillation kettle. The defoamer is composed of the following components: 11 parts of hydrocarbonized oil, 10 parts of graphite oxide, 7 parts of composite emulsifier, 0.2 parts of thickener, 0.1 part of preservative, and deionized water. 130 parts. The preparation method is to stir and mix the hydrocarbonated oil and graphene oxide; then add the compound emulsifier, thickener, preservative, and finally slowly add deionized water, stir and mix well. The amount of defoamer is 0.3%; heat up the distillation kettle. When the temperature reaches 80 ° C, it will be recovered under reduced pressure. When the vacuum is 0.08Mpa and the temperature is 125 ° C, turn off the steam, stop heating, continue the vacuum for 60min, and the final temperature is 125 ° C. The vacuum was released until there was no distillate in the cylinder.

S6: suction filtration

Use a suction pump to pump the solution obtained from S5 into a vacuum suction filtration device to start suction filtration. After the suction filtration is dried, rinse the residue on the filter membrane with 0.8% citric acid ethanol solution, and then wash and dry with deionized water. The liquid is the finished product. The pore size of the filter membrane used for vacuum filtration is 30 μm.

After inspection, in the obtained methoxymethyl melamine resin rubber adhesive, the free formaldehyde content was 6.0%, the combined formaldehyde content was 38%, and the density of the methoxymethyl melamine resin rubber adhesive was 1.021 g / cm ³ ; the product is unqualified.

Embodiment 2: A process for preparing a hexamethoxymethyl melamine resin rubber adhesive, which is characterized in that it mainly includes the following steps:

S1: Feeding

Put the methanol into the etherification kettle with a beater and stir. Then add hexahydroxy to the etherification kettle and continue stirring. Among them, methanol and hexahydroxy are added twice. First, add a portion of methanol to the etherification kettle, and then Add a portion of hexahydroxy to the etherification kettle, stir for the first time, then put the remaining methanol and hexahydroxy into the mixture, and stir for the second time; during the first stirring process, add catalyst to the etherification kettle; The added amount is 9000Kg, and the added amount of hexahydroxide is 4500Kg. First, 5000Kg of methanol is added to the etherification kettle, and then 2000Kg of hexahydroxy is added to the etherification kettle, and the first stirring speed is 500RPM. , The first stirring temperature is 25 ° C, the first stirring time is 20min; then the remaining methanol and hexahydroxy are added to the etherification kettle, and the second stirring is performed, the second stirring speed is 300RPM, and the second The stirring temperature is 20 ° C, and the second stirring time is 10 minutes. The catalyst is a triethylamine, diisobutylaluminum hydride, chloropropane, isopropanol composite catalyst, triethylamine, diisobutylaluminum hydride, and chloro. The ratio of propane (mol / mol / mol / mol) is 1.2 : 4.5: 0.2: 0.1; Triethylamine, diisobutylaluminum hydride, chloropropane, and isopropanol were added to the preparation kettle in that order. The temperature of the preparation kettle was controlled at 6 ° C, and the mixture was stirred for 48 minutes. Finished catalyst

S2: etherification

After the feeding, the etherification kettle was heated to 53 ° C and subjected to heat preservation treatment. Sulfuric acid was added to the etherification kettle to adjust the pH. After the sulfuric acid was added, the pH was measured every 5 minutes, and the last measurement was pH = 2; The catalyst was added to the mixture and stirred, and the reaction was performed at a temperature of 53 ° C. After the materials became clear, the reaction was continued for 90 minutes;

S3: Neutralize

After the etherification reaction is completed, when the temperature is 53 ° C, a sodium hydroxide solution is added to the solution obtained in S2 to neutralize the reaction. After the addition, the pH value is measured once every 5 minutes, three times, and the last time pH = 8.1; use;

S4: Recovery of methanol

2) The hexamethoxymethyl melamine resin rubber binder mixed solution containing the methanol solution after preliminary heat exchange enters the top of the distillation kettle, and the methanol mixture flashed after the reboiler is heated is sprayed on the top of the distillation kettle. The mixed solution containing the hexamethoxymethyl melamine resin rubber adhesive was subjected to reverse contact heat exchange, and the methanol content in the hexamethoxymethyl melamine resin rubber adhesive solution discharged from the top of the distillation kettle was zero; The boiler uses medium-pressure steam to heat the alcohol-containing hexamethoxymethyl melamine resin rubber binder solution in the etherification kettle. The top temperature of the distillation kettle is 100 ° C, the temperature at the bottom of the tower is 138 ° C, and the pressure is normal pressure. The temperature of the gas phase after cooling is 25 ° C, and the temperature of the gas phase after cooling is 12 ° C, which ensures that the methanol can be completely condensed. The pressure of the primary cooling tower and the secondary cooling tower is 0.2MPa, and the primary cooling tower and the secondary cooling tower are both The reflux liquid obtained at the bottom of the column contained a small amount of a mixture of methanol and water;

4) The condensate overflowing from the bottom of the primary cooling tower and the secondary cooling tower enters the bottom of the distillation kettle under the action of pressure difference and pressure difference, and the gas phase hexamethoxymethylmelamine resin rubber adhesive enters the etherification at the same time. The top of the kettle is contacted in a distillation kettle to produce formaldehyde. The pressure of the distillation kettle is 100KPa and the temperature of the bottom of the distillation kettle is 95 ° C.

S5: Distillation

Add defoaming agent to the distillation kettle. The defoaming agent is composed of the following components: 10 parts of hydrocarbon oil, 8 parts of graphene oxide, 6 parts of composite emulsifier, 0.1 part of thickener, 0.1 part of preservative, and deionization. 120 parts of water. The preparation method is to stir and mix the hydrocarbonated oil and graphene oxide; then add the compound emulsifier, thickener, preservative, and finally slowly add deionized water, stir and mix well. The temperature is 0.3%; the distillation kettle is heated up. When the temperature reaches 80 ° C, it is recovered under reduced pressure. When the vacuum is 0.09Mpa and the temperature is 130 ° C, the steam is turned off. The heating is stopped and the vacuum is continued for 90min. The final temperature is 130 ° C. The vacuum was released until there was no distillate in the cylinder.

S6: suction filtration

Use a suction pump to pump the solution obtained from S5 into a vacuum suction filtration device to start suction filtration. After the suction filtration is dried, rinse the residue on the filter membrane with 0.8% citric acid ethanol solution, and then wash and dry with deionized water. The liquid is the finished product, and the pore size of the filter membrane used for vacuum filtration is 40 μm.

After inspection, the obtained methoxymethyl melamine resin rubber adhesive has a free formaldehyde content of 5% and a combined formaldehyde content of 40%. The density of the methoxymethyl melamine resin rubber adhesive is 1.001 g / cm ³ ; the product is unqualified.

Embodiment 3: A process for preparing a hexamethoxymethyl melamine resin rubber adhesive, which is characterized in that it mainly includes the following steps:

S1: Feeding

Put the methanol into the etherification kettle with a beater and stir. Then add hexahydroxy to the etherification kettle and continue stirring. Among them, methanol and hexahydroxy are added twice. First, add a portion of methanol to the etherification kettle, and then Add a portion of hexahydroxy to the etherification kettle, stir for the first time, then put the remaining methanol and hexahydroxy into the mixture, and stir for the second time; during the first stirring process, add catalyst to the etherification kettle; The added amount is 10000Kg, and the amount of hexahydroxy is 5000Kg. First, add 6000Kg of methanol to the etherification kettle, and then add 2800Kg of hexahydroxy to the etherification kettle, and perform the first agitation. The first agitation speed is 500RPM. , The first stirring temperature is 25 ° C, the first stirring time is 20min; then the remaining methanol and hexahydroxy are added to the etherification kettle, and the second stirring is performed, the second stirring speed is 300RPM, and the second The stirring temperature is 20 ° C, and the second stirring time is 10 minutes. The catalyst is a triethylamine, diisobutylaluminum hydride, chloropropane, isopropanol composite catalyst, triethylamine, diisobutylaluminum hydride, and chloro. The ratio of propane (mol / mol / mol / mol) is 1 .2: 4.5: 0.2: 0.1; add triethylamine, diisobutylaluminum hydride, chloropropane, isopropanol to the preparation kettle in order, control the temperature of the preparation kettle at 8 ° C, and stir for 50min. The obtained product is The finished catalyst;

S2: etherification

After the feeding, the etherification kettle was heated to 58 ° C and subjected to heat preservation treatment. Sulfuric acid was added to the etherification kettle to adjust the pH. After the sulfuric acid was added, the pH value was measured every 5 minutes, and the last pH = 3 was measured. The catalyst was added to the mixture and stirred, and the reaction was performed at a temperature of 58 ° C. After the material became clear, the reaction was continued for 120 minutes;

S3: Neutralize

After the etherification reaction is completed, when the temperature is 58 ° C, a sodium hydroxide solution is added to the solution obtained in S2 to neutralize the reaction. After the addition, the pH value is measured once every 5 minutes, three times, and the last time pH = 9; use;

S4: Recovery of methanol

2) The hexamethoxymethyl melamine resin rubber binder mixed solution containing the methanol solution after preliminary heat exchange enters the top of the distillation kettle, and the methanol mixture flashed after the reboiler is heated is sprayed on the top of the distillation kettle. The mixed solution containing the hexamethoxymethyl melamine resin rubber adhesive was subjected to reverse contact heat exchange, and the methanol content in the hexamethoxymethyl melamine resin rubber adhesive solution discharged from the top of the distillation kettle was zero; The boiler uses medium-pressure steam to heat the alcohol-containing hexamethoxymethyl melamine resin rubber binder solution in the etherification kettle. The top temperature of the distillation kettle is 120 ° C, the temperature at the bottom of the tower is 140 ° C, and the pressure is normal pressure. The temperature of the gas phase after cooling is 15 ° C, and the temperature of the gas phase after secondary cooling is 10 ° C. The pressure of the primary cooling tower and the secondary cooling tower are both 0.2 MPa. The reflux liquid obtained at the bottom of the primary cooling tower and the secondary cooling tower contains A small amount of a mixture of methanol and water;

4) The condensate overflowing from the bottom of the primary cooling tower and the secondary cooling tower enters the bottom of the distillation kettle under the action of pressure difference and pressure difference, and the gas phase hexamethoxymethylmelamine resin rubber adhesive enters the etherification at the same time. The top of the kettle is contacted in a distillation kettle to produce formaldehyde. The pressure of the distillation kettle is 110KPa and the temperature of the bottom of the distillation kettle is 95 ° C.

S5: Distillation

Add defoaming agent to the distillation kettle. The defoaming agent is composed of the following components: 15 parts of hydrocarbonated oil, 13 parts of graphite oxide, 8 parts of composite emulsifier, 0.3 parts of thickener, 0.2 parts of preservative, and deionized water. 145 parts. The preparation method is to stir and mix the hydrocarbonated oil and graphene oxide; then add the compound emulsifier, thickener, and preservative, and finally slowly add deionized water, stir and mix well. The amount of defoamer is 0.8%; The distillation kettle is heated up. When the temperature reaches 80 ° C, it is recovered under reduced pressure. When the vacuum is 0.1Mpa and the temperature is 135 ° C, the steam is turned off. The heating is stopped and the vacuum is continued for 120min. The final temperature is 140 ° C. The vacuum was released until there was no distillate in the cylinder.

S6: suction filtration

Use a suction pump to pump the solution obtained from S5 into a vacuum suction filtration device to start suction filtration. After the suction filtration is dried, rinse the residue on the filter membrane with 0.8% citric acid ethanol solution, and then wash and dry with deionized water. The liquid is the finished product, and the pore size of the filter membrane used for vacuum filtration is 50 μm.

After inspection, the obtained methoxymethyl melamine resin rubber adhesive has a free formaldehyde content of 4.5% and a combined formaldehyde content of 44%. The density of the methoxymethyl melamine resin rubber adhesive is 1.200 g / cm ³ ; the product is qualified.

Embodiment 4: A process for preparing a hexamethoxymethyl melamine resin rubber adhesive, which is characterized in that it mainly includes the following steps:

S1: Feeding

Put the methanol into the etherification kettle with a beater and stir. Then add hexahydroxy to the etherification kettle and continue stirring. Among them, methanol and hexahydroxy are added twice. First, add a portion of methanol to the etherification kettle, and then Add a portion of hexahydroxy to the etherification kettle, stir for the first time, then put the remaining methanol and hexahydroxy into the mixture, and stir for the second time; during the first stirring process, add catalyst to the etherification kettle; The added amount is 10000Kg, and the amount of hexahydroxy is 5000Kg. First, add 6000Kg of methanol to the etherification kettle, and then add 2800Kg of hexahydroxy to the etherification kettle, and perform the first agitation. The first agitation speed is 500RPM. , The first stirring temperature is 25 ° C, the first stirring time is 20min; then the remaining methanol and hexahydroxy are added to the etherification kettle, and the second stirring is performed, the second stirring speed is 300RPM, and the second The stirring temperature is 20 ° C, and the second stirring time is 10 minutes. The catalyst is a triethylamine, diisobutylaluminum hydride, chloropropane, isopropanol composite catalyst, triethylamine, diisobutylaluminum hydride, and chloro. The ratio of propane (mol / mol / mol / mol) is 1. 2: 4.5: 0.2: 0.1; add triethylamine, diisobutylaluminum hydride, chloropropane, and isopropanol to the preparation kettle in turn, control the temperature of the preparation kettle at 8 ° C, and stir for 50min, and the obtained product will be Mentioned catalyst finished product;

S2: etherification

S3: Neutralize

S4: Recovery of methanol

4) The condensate overflowing from the bottom of the primary cooling tower and the secondary cooling tower enters the bottom of the distillation kettle under the action of pressure difference and pressure difference, and the gas phase hexamethoxymethylmelamine resin rubber adhesive enters the etherification The top of the kettle is contacted in a distillation kettle to produce formaldehyde. The pressure of the distillation kettle is 110KPa and the temperature of the bottom of the distillation kettle is 95 ° C.

S5: Distillation

The distillation kettle was heated up. When the temperature reached 80 ° C, it was recovered under reduced pressure. When the vacuum was 0.1Mpa and the temperature was 135 ° C, the steam was turned off. The heating was stopped and the vacuum was continued for 120min. The final temperature was 140 ° C. Until the distillate is removed, the vacuum is released.

S6: suction filtration

The difference between Example 4 and Example 3 is that no defoamer was added in Example 4.

After inspection, in the obtained methoxymethyl melamine resin rubber adhesive, the free formaldehyde content was 5.1%, the combined formaldehyde content was 44%, and the density of the methoxymethyl melamine resin rubber adhesive was 1.210 g / cm ³ ; the product is unqualified.

In the end, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, but not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that it can still Modifications to the technical solutions described in the foregoing embodiments, or equivalent replacements of some of the technical features thereof; and these modifications or replacements do not depart the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

A process for preparing a hexamethoxymethyl melamine resin rubber adhesive is characterized in that it mainly includes the following steps:

S1: Feeding

Put the methanol into the etherification kettle with a beater and stir. Then add hexahydroxy to the etherification kettle and continue stirring. Among them, methanol and hexahydroxy are added twice. First, add a portion of methanol to the etherification kettle, and then Add a part of the hexahydroxyl to the etherification kettle, stir for the first time, and then put the remaining methanol and hexahydroxyl into it for the second stirring; during the first stirring process, add the catalyst to the etherification kettle;

S2: etherification

After the feeding, the etherification kettle was heated to 48 ° C-58 ° C and subjected to heat preservation treatment. Sulfuric acid was added to the etherification kettle to adjust the pH. The pH was measured every 5 minutes after the addition of sulfuric acid, and the last measurement was pH = 2- 3; Then add a catalyst to the solution and stir, and carry out the reaction at a temperature of 48 ° C-58 ° C. After the material becomes clear, continue the reaction for 60-120 minutes;

S3: Neutralize

After the etherification reaction is completed, when the temperature is 48 ° C-58 ° C, a sodium hydroxide solution is added to the solution obtained in S2 to neutralize the reaction. After the addition, the pH value is measured once every 5 minutes, three times, and the last time pH = 8-9; standby

S4: Recovery of methanol

1) The hexamethoxymethyl melamine resin rubber binder mixed solution containing a methanol solution is pumped into a heat exchanger by a pump, and the hexamethoxymethyl discharged from the bottom of the distillation kettle is heated in the heat exchanger. Melamine resin rubber binder mixture for preliminary heat exchange;

2) The hexamethoxymethyl melamine resin rubber binder mixed solution containing the methanol solution after preliminary heat exchange enters the top of the distillation kettle, and the methanol mixture flashed after the reboiler is heated is sprayed on the top of the distillation kettle. The mixed solution containing the hexamethoxymethyl melamine resin rubber adhesive was subjected to reverse contact heat exchange, and the methanol content in the hexamethoxymethyl melamine resin rubber adhesive solution discharged from the top of the distillation kettle was zero;

3) The mixture of hexamethoxymethyl melamine resin rubber adhesive and methanol overflowing from the top of the distillation kettle is cooled by a cooling tower. After cooling, the methanol and hexamethoxymethyl melamine resin rubber adhesive are all condensed. Part of the reflux liquid enters the bottom of the distillation kettle;

4) The condensate overflowing from the bottom of the primary cooling tower and the secondary cooling tower enters the bottom of the distillation kettle under the action of pressure difference and pressure difference, and the gas phase hexamethoxymethylmelamine resin rubber adhesive enters the etherification at the same time. The top of the kettle is contacted to produce formaldehyde in the distillation kettle, the pressure of the distillation kettle is 90-110KPa, and the temperature of the bottom of the distillation kettle is 95 ° C;

S5: Distillation

The distillation kettle is heated up. When the temperature reaches 75-85 ° C, it is recovered under reduced pressure. When the vacuum is 0.08-0.1Mpa and the temperature is 125 ° -135 ° C, the steam is turned off, the heating is stopped, and the vacuum is continued for 60-120min. Finally, The temperature is 125 ° C-140 ° C, and the vacuum is released until there is no distillate in the tube.

S6: suction filtration

Use a suction pump to pump the solution obtained from S5 into a vacuum suction filtration device to start suction filtration. After the suction filtration is dried, rinse the residue on the filter membrane with 0.8% citric acid ethanol solution, and then wash and dry with deionized water. Liquid is the finished product.
The process for preparing a hexamethoxymethyl melamine resin rubber adhesive according to claim 1, characterized in that in the step S1, the dosage of methanol is 8000-10000Kg, and the dosage of hexahydroxy is The amount is 4000-5000Kg; firstly add 4000-5000Kg of methanol to the etherification kettle, and then add 2000-2500Kg of hexahydroxy to the etherification kettle for the first stirring, the first stirring speed is 500RPM, the first time The stirring temperature is 25 ° C, and the first stirring time is 20min. Then, the remaining methanol and hexahydroxyl are separately added to the etherification kettle, and the second stirring is performed. The second stirring speed is 300RPM and the second stirring temperature is 20 ℃, the second stirring time was 10min.
The process for preparing a hexamethoxymethyl melamine resin rubber adhesive according to claim 1, wherein in the step S1, the catalyst is triethylamine, diisobutylaluminum hydride, Chloropropane, isopropanol composite catalyst, the ratio (mol / mol / mol / mol) of triethylamine, diisobutylaluminum hydride, and chloropropane is 1.2: 4.5: 0.2: 0.1; sequentially add to the preparation kettle Triethylamine, diisobutylaluminum hydride, chloropropane, and isopropanol. The temperature of the preparation kettle was controlled at 0-8 ° C. and stirred for 40-55 min. The obtained product was the finished catalyst product.
The process for preparing a hexamethoxymethyl melamine resin rubber adhesive according to claim 1, wherein in step S4, the reboiler uses medium-pressure steam to heat the alcohol-containing alcohol in the etherification kettle. Hexamethoxymethyl melamine resin rubber binder solution, the top temperature of the distillation kettle is 85-120 ° C, the temperature at the bottom of the tower is 136-140 ° C, the pressure is normal pressure, and the temperature of the gas phase after first-stage cooling is 10-35 ° C. After the secondary cooling, the temperature of the gas phase is 8-15 ° C, ensuring that methanol can be completely condensed. The pressure of the primary cooling tower and the secondary cooling tower are 0.2 MPa, and the bottom of the primary cooling tower and the secondary cooling tower are at the bottom. The resulting reflux liquid contained a small amount of a mixture of methanol and water.
The process for preparing a hexamethoxymethyl melamine resin rubber adhesive according to claim 1, characterized in that, in the step S4, the hexamethoxymethyl melamine resin rubber overflowing from the top of the distillation kettle The mixed gas of the binder and methanol passes through the primary cooling tower and the secondary cooling tower in this order. In the primary cooling tower, part of the methanol and hexamethoxymethylmelamine resin rubber binder are condensed. The uncooled methanol and The hexamethoxymethyl melamine resin rubber adhesive enters the secondary cooling tower and continues to condense. After two stages of cooling, the methanol and hexamethoxymethyl melamine resin rubber adhesive all condense, and a part of the reflux liquid enters the distillation kettle. bottom.
The process for preparing a hexamethoxymethyl melamine resin rubber adhesive according to claim 1, characterized in that before performing step S5, an antifoaming agent is added to the distillation kettle, said antifoaming agent It is composed of the following components: 10-15 parts of hydrocarbonated oil, 8-13 parts of graphene oxide, 6-8 parts of composite emulsifier, 0.1-0.3 parts of thickener, 0.1-0.2 parts of preservative, and 120 deionized water -150 parts, the preparation method is to stir and mix the hydrocarbonated oil and graphene oxide; then add the compound emulsifier, thickener, preservative, and finally slowly add deionized water, stir and mix well.