CN105622878B - A kind of preparation method of aqueous waterproofing paint - Google Patents

Abstract

The invention discloses a kind of preparation method of aqueous waterproofing paint.Isocyanate terminated base polyurethane prepolymer for use as is obtained by polyether Glycols and di-isocyanate reaction；Epoxy radicals silicone hydride is added dropwise into performed polymer, 0.5 1.5h of reaction is kept at 75 85 DEG C；60 70 DEG C of dropwise addition hydrophilic chain extenders are cooled to, react 0.5 1.5h；25 35 DEG C are cooled to, salt forming agent is added dropwise, reacts 20 30min；Distilled water and chain extender are added, reacts 30 50min under strong stirring；Carboxylic acid fluoride ammonium salt is added, strong stirring is uniformly mixed, and obtains epoxy radicals silicone hydride/carboxylic acid fluoride ammonium salt/polyurethane aqueous water-repellent paint.When as construction material and car surface coating when other purposes, compared to common water borne polyurethane, its water resistance has obtained very big improvement, will be enlarged by application of the aqueous polyurethane in high-performance coating field.

Description

A kind of preparation method of water-based waterproof coating

technical field

The invention belongs to the technical field of coatings, and in particular relates to a preparation method of a modified polyurethane water-based waterproof coating.

Background technique

The synthesis of waterborne polyurethane needs to introduce hydrophilic groups, resulting in excessive surface tension and poor waterproof and water resistance. Due to the limitations of the synthesis process, the relative molecular weight of water-based polyurethane dispersions is lower than that of solvent-based polyurethane materials. In addition, the self-emulsifying system introduces hydrophilic groups on its chain segments, such as amino (-NH ₂ ), hydroxyl (-COOH) or sulfonic acid groups (-SO ₃ H), etc. These hydrophilic groups make the coating The water resistance of the membrane is affected, and the water resistance is poor during use, and it is easy to whiten and bubble, which limits the application of water-based polyurethane coatings in the field of high-performance coatings.

At present, researchers have made many improvements to improve the water resistance of waterborne polyurethane. The modification methods are mainly divided into two categories, cross-linking modification and surface modification. The cross-linking modification links the linear polyurethane macromolecules together in the form of chemical bonds, and the modified polyurethane has good waterproof performance; the surface modification is to reduce its surface tension by introducing low surface energy materials into the water-based polyurethane emulsion, thereby To achieve the purpose of improving water resistance. However, most of the current systems use a single method or material to modify waterborne polyurethane, which has certain limitations and cannot most effectively improve its water resistance.

Contents of the invention

The purpose of the present invention is to provide an epoxy silane/ammonium fluorocarboxylate/polyurethane water-based waterproof coating with excellent water resistance.

A preparation method of water-based waterproof paint, comprising the following steps:

1) obtain the polyurethane prepolymer of terminal isocyanate by reaction of polyether glycol and diisocyanate;

2) Add epoxy silane dropwise to the prepolymer, and keep the reaction at 75-85°C for 0.5-1.5h;

3) Cool down to 60-70°C and add hydrophilic chain extender dropwise, react for 0.5-1.5h;

4) Cool down to 25-35°C, add salt-forming agent dropwise, and react for 20-30 minutes;

5) Add distilled water and chain extender, and react for 30-50 minutes under strong stirring;

6) Add ammonium fluorocarboxylate, stir and mix evenly to obtain epoxy silane/ammonium fluorocarboxylate/polyurethane water-based waterproof coating;

Wherein, the raw materials used are as follows in parts by weight:

15-25 parts of polyether diol

4-6.5 parts of diisocyanate

1-1.5 parts of epoxy silane

Hydrophilic chain extender 1-1.5 parts

Salt forming agent 0.8-1.1 parts

50-70 parts of distilled water

Chain extender 0.2-0.4 parts

0.2-0.4 part of ammonium fluorocarboxylate.

According to the above scheme, the ammonium fluorocarboxylate is prepared in the following way:

Using N-ethyl, N-hydroxyethyl perfluorooctane sulfonamide (DF-10) and succinic anhydride as raw materials, DMF as solvent, and 4-dimethylazinopyridine (DMAP) as catalyst to prepare fluorocarboxylic acid (FCA); take fluorocarboxylic acid and TEA as raw materials, synthesize the fluorocarboxylate solution soluble in water.

According to the above scheme, step 1) the molar ratio of isocyanate group and hydroxyl group is 3:1.

According to the above scheme, the diisocyanate is toluene diisocyanate, diphenylmethane diisocyanate or hexamethylene diisocyanate.

According to the above scheme, the polyether glycol is polyethylene glycol (PEG2000) or polypropylene glycol (PPG2000) with an average molecular weight of 2000.

According to the above scheme, the hydrophilic chain extender is 2-2 dimethylolpropionic acid (DMPA); it is dissolved in N-N dimethylformamide (DMF) and added to the reaction system.

According to the above scheme, the epoxy silane is γ-(2,3-glycidoxy)propyltrimethoxysilane (KH-560).

According to the above scheme, the salt-forming agent is triethylamine (TEA).

According to the above scheme, the chain extender is ethylenediamine (EDA).

Aiming at the problem of poor water resistance of water-based polyurethane; it is modified with organic silicon and organic fluorine at the same time. Epoxy silane has low surface tension, and epoxy group can react with isocyanate to form a network structure, preventing moisture from entering the interior of the coating; ammonium fluorocarboxylate contains the same functional groups as waterborne polyurethane chains, and its aqueous solution can Blended with water-based polyurethane emulsion to reduce the surface tension of the emulsion, ammonium fluorocarboxylate migrates to the surface of the coating during the film-forming process of the coating.

Compared with the prior art, the beneficial effects of the present invention are as follows:

The organic fluorine involved in the present invention is ammonium fluorocarboxylate, and the aqueous solution of ammonium fluorocarboxylate contains the same functional group as water-based polyurethane and has good compatibility. The introduced organic fluorine molecules are small, and it is easier to migrate to the surface of the coating film during the film formation process. Only a small amount of organic fluorine is added to achieve the surface hydrophobic effect.

The water-based polyurethane paint synthesized by the invention has excellent water resistance, greatly reduces surface tension, and the surface contact angle also meets the requirement of hydrophobicity.

When used as building wall materials and automotive surface coatings, its waterproof performance has been greatly improved compared with ordinary water-based polyurethanes, which will expand the application of water-based polyurethanes in the field of high-performance coatings.

Detailed ways

The following examples further illustrate the technical solutions of the present invention, but are not intended to limit the protection scope of the present invention.

The preparation process of ammonium fluorocarboxylate is as follows:

1) 55-65℃, N-ethyl, N-hydroxyethyl perfluorooctane sulfonamide and succinic anhydride are dissolved in N-N dimethylformamide respectively;

2) N-ethyl, N-hydroxyethyl perfluorooctane sulfonamide solution and succinic anhydride solution are blended, kept at 55-65°C for 25-35min;

3) Heat up to 85-95°C, add catalyst 4-dimethylazinopyridine, and react for 7.5-8.5h;

4) Quickly pour distilled water for extraction, filter and wash several times, and then dry to obtain fluorocarboxylic acid;

5) Add triethylamine aqueous solution to fluorocarboxylic acid, react at 20-30°C for 3-4h to obtain fluorocarboxylic acid ammonium salt (FAC) solution.

Example 1

Place PPG2000 in a three-necked flask, heat up and vacuumize, and perform dehydration treatment. Under the conditions of internal temperature of 110°C and vacuum degree of 133.3Pa, the treatment time is 2.0h; PPG2000 is added to the reactor, and TDI is added dropwise , react at 75°C for 0.5h under nitrogen atmosphere, add catalyst, react at 80°C for 1.0h to obtain a polyurethane prepolymer, and keep the rotation speed at 60r/min during the reaction.

Keep the system at 80°C, add KH-560 dropwise, the dropping rate is one drop every two seconds, stir for 1.0h, and the speed is 60r/min; cool down to 65°C, add DMPA dropwise, the dropping speed is one drop for two seconds, stir for 1.0h, and the speed is 60r/min. 60r/min; cool down to 30°C, add TEA dropwise at a rate of one drop every two seconds, react for 20min, and rotate at a speed of 120r/min; add distilled water and EDA, and react for 40min under strong stirring; Waterborne polyurethane emulsion.

Accurately weigh the FAC solution, add it to the epoxy silane-modified water-based polyurethane emulsion, and stir vigorously for 30 minutes at a speed of 180 r/min. After the reaction is completed, samples are collected to obtain epoxy silane/ammonium fluorocarboxylate/polyurethane water-based waterproof coating.

According to relevant test standards, the relevant performance of epoxy silane/ammonium fluorocarboxylate/polyurethane water-based waterproof coating was tested. The surface tension of the coating was 17.9mN/m; the water absorption rate of the coating film was 7.14% after soaking in water for 24 hours; the surface hydrophobicity is 114°.

Example 2

Place PPG2000 in a three-necked flask, heat up and vacuumize, and perform dehydration treatment. Under the conditions of internal temperature of 110°C and vacuum degree of 133.3Pa, the treatment time is 2.0h; PPG2000 is added to the reactor, and MDI is added dropwise , reacted at 75°C for 0.5h under a nitrogen atmosphere, added catalyst, reacted at 80°C for 1.0h, and kept the rotation speed at 60r/min during the reaction.

Keep the system at 82°C, add KH-560 dropwise, the dropping rate is every two seconds, stir for 0.7h, and the speed is 60r/min; cool down to 68°C, add DMPA dropwise, the dropping speed is every two seconds, stir for 0.7h, and the speed is 60r/min. 60r/min; cool down to 32°C, add TEA dropwise at a rate of one drop every two seconds, react for 22min, and rotate at a speed of 120r/min; add distilled water and EDA, and react for 45min under strong stirring; Waterborne polyurethane emulsion.

Accurately weigh the FAC solution, add it to the epoxy silane-modified water-based polyurethane emulsion, and stir vigorously for 30 minutes at a speed of 180 r/min. After the reaction is completed, samples are collected to obtain epoxy silane/ammonium fluorocarboxylate/polyurethane water-based waterproof coating.

According to relevant test standards, the relevant properties of epoxy silane/ammonium fluorocarboxylate/polyurethane water-based waterproof coating were tested. The surface tension of the coating was 18.0mN/m; the water absorption rate of the coating film was 7.26% after soaking in water for 24 hours; the surface hydrophobicity is 113°.

Example 3

PPG2000 is placed in a three-necked flask, heated up and vacuumed, and dehydrated. Under the conditions of internal temperature of 110°C and vacuum degree of 133.3Pa, the treatment time is 2.0h; PPG2000 is added to the reactor, and HDI is added dropwise , reacted at 75°C for 0.5h under a nitrogen atmosphere, added catalyst, reacted at 80°C for 1.0h, and kept the rotation speed at 60r/min during the reaction.

Keep the system at 80°C, add KH-560 dropwise, the drop rate is every two seconds, stir for 1.2 hours, and the speed is 60r/min; cool down to 65°C, add DMPA dropwise, the drop rate is every two seconds, stir for 1.2h, and the speed is 60r/min. 60r/min; cool down to 30°C, add TEA dropwise at a rate of one drop every two seconds, react for 30min, and rotate at a speed of 120r/min; add distilled water and EDA, and react for 40min under strong stirring; Waterborne polyurethane emulsion.

Accurately weigh the FAC solution, add it to the epoxy silane-modified water-based polyurethane emulsion, and stir vigorously for 30 minutes at a speed of 180 r/min. After the reaction is completed, samples are collected to obtain epoxy silane/ammonium fluorocarboxylate/polyurethane water-based waterproof coating.

According to relevant test standards, the relevant performance of epoxy silane/ammonium fluorocarboxylate/polyurethane water-based waterproof coating is tested. The surface tension of the coating is 18.1mN/m; the water absorption rate of the coating film is 7.35% after soaking in water for 24 hours; the surface hydrophobicity is 110°.

Example 4

Put PEG2000 in a three-necked flask, heat up and vacuumize, and perform dehydration treatment. Under the conditions of internal temperature of 110°C and vacuum degree of 133.3Pa, the treatment time is 2.0h; PPG2000 is added to the reactor, and TDI is added dropwise , reacted at 75°C for 0.5h under a nitrogen atmosphere, added catalyst, reacted at 80°C for 1.0h, and kept the rotation speed at 60r/min during the reaction.

Keep the system at 78°C, add KH-560 dropwise, the dropping rate is one drop per second, stir for 1.2 hours, and the speed is 60r/min; cool down to 70°C, add DMPA dropwise, the dropping speed is one drop for two seconds, stir for 1.0h, and the speed is 60r/min. 60r/min; lower the temperature to 28°C, add TEA dropwise at a rate of one drop every two seconds, react for 35min, and rotate at a speed of 120r/min; add distilled water and EDA, and react for 45min under strong stirring; Waterborne polyurethane emulsion.

Accurately weigh the FAC solution, add it to the epoxy silane-modified water-based polyurethane emulsion, and stir vigorously for 30 minutes at a speed of 180 r/min. After the reaction is completed, samples are collected to obtain epoxy silane/ammonium fluorocarboxylate/polyurethane water-based waterproof coating.

According to relevant test standards, the relevant performance of epoxy silane/ammonium fluorocarboxylate/polyurethane water-based waterproof coating is tested. The surface tension of the coating is 18.1mN/m; the water absorption rate of the coating film is 7.32% after soaking in water for 24 hours; the surface hydrophobicity is 112°.

Example 5

Place PEG2000 in a three-necked flask, heat up and vacuumize, and perform dehydration treatment. Under the conditions of internal temperature of 110°C and vacuum degree of 133.3Pa, the treatment time is 2.0h; PPG2000 is added to the reactor, and MDI is added dropwise , reacted at 75°C for 0.5h under a nitrogen atmosphere, added catalyst, reacted at 80°C for 1.0h, and kept the rotation speed at 60r/min during the reaction.

Keep the system at 85°C, add KH-560 dropwise, the dropping rate is one drop per second, stir for 0.7h, and the speed is 60r/min; cool down to 70°C, add DMPA dropwise, the dropping speed is one drop for two seconds, stir for 0.7h, and the speed is 60r/min. 60r/min; cool down to 25°C, add TEA dropwise at a rate of one drop every two seconds, react for 30min, and rotate at a speed of 120r/min; add distilled water and EDA, and react for 40min under strong stirring; Waterborne polyurethane emulsion.

Accurately weigh the FAC solution, add it to the epoxy silane-modified water-based polyurethane emulsion, and stir vigorously for 30 minutes at a speed of 180 r/min. After the reaction is completed, samples are collected to obtain epoxy silane/ammonium fluorocarboxylate/polyurethane water-based waterproof coating.

According to relevant test standards, the relevant performance of epoxy silane/ammonium fluorocarboxylate/polyurethane water-based waterproof coating was tested. The surface tension of the coating was 17.9mN/m; the water absorption rate of the coating film was 7.19% after soaking in water for 24 hours; the surface hydrophobicity is 114°.

Claims (8)

1. a kind of preparation method of aqueous waterproofing paint, it is characterised in that comprise the following steps：

1) isocyanate terminated base polyurethane prepolymer for use as is obtained by polyether Glycols and di-isocyanate reaction；

2) epoxy radicals silicone hydride is added dropwise into performed polymer, reaction 0.5-1.5h is kept at 75-85 DEG C；

3) 60-70 DEG C of dropwise addition hydrophilic chain extender is cooled to, reacts 0.5-1.5h；

4) 25-35 DEG C is cooled to, salt forming agent is added dropwise, reacts 20-30min；

5) distilled water and chain extender are added, reacts 30-50min under strong stirring；

6) carboxylic acid fluoride ammonium salt is added, strong stirring is uniformly mixed, and obtains epoxy radicals silicone hydride/carboxylic acid fluoride ammonium salt/polyurethane aqueous anti- Water paint；

Wherein, raw materials used meter in parts by weight is as follows：

15-25 parts of polyether Glycols

4-6.5 parts of diisocyanate

1-1.5 parts of epoxy radicals silicone hydride

1-1.5 parts of hydrophilic chain extender

0.8-1.1 parts of salt forming agent

50-70 parts of distilled water

0.2-0.4 parts of chain extender

0.2-0.4 parts of carboxylic acid fluoride ammonium salt；

The carboxylic acid fluoride ammonium salt is prepared as follows：With N- ethyls, N- ethoxys perfluorinated octyl sulfuryl amine (DF-10) and Succinic anhydride is raw material, and DMF is solvent, and 4- diformazan nitrogen yl pyridines (DMAP) go out carboxylic acid fluoride (FCA) for catalyst preparation；With fluorine Carboxylic acid and TEA are raw material, and synthesis is dissolved in the carboxylic acid fluoride salting liquid of water.

2. the preparation method of aqueous waterproofing paint as claimed in claim 1, it is characterised in that step 1) isocyanate group and hydroxyl Molar ratio be 3：1.

3. the preparation method of aqueous waterproofing paint as claimed in claim 1, it is characterised in that the diisocyanate is toluene two Isocyanates, methyl diphenylene diisocyanate or hexamethylene diisocyanate.

4. the preparation method of aqueous waterproofing paint as claimed in claim 1, it is characterised in that the polyether Glycols are average marks The polyethylene glycol or polypropylene glycol that son amount is 2000.

5. the preparation method of aqueous waterproofing paint as claimed in claim 1, it is characterised in that the hydrophilic chain extender is 2,2- Double hydroxymethyl propionic acids；N is dissolved in, reaction system is added after N- dimethylformamides.

6. the preparation method of aqueous waterproofing paint as claimed in claim 1, it is characterised in that the epoxy radicals silicone hydride be γ-(2, The third oxygen of 3- epoxies) propyl trimethoxy silicane.

7. the preparation method of aqueous waterproofing paint as claimed in claim 1, it is characterised in that the salt forming agent is triethylamine.

8. the preparation method of aqueous waterproofing paint as claimed in claim 1, it is characterised in that the chain extender is ethylenediamine.