Summary of the invention
The objective of the invention is to high-performance water-based epoxy cold coating that proposes a kind of non-environmental-pollution and preparation method thereof.
The aqueous epoxide resin paint that the present invention proposes is a high-performance dual-component coating, is made up of epoxy resin latex and two components of aqueous epoxy resin curing agent.
Wherein, epoxy resin latex is prepared through reactive emulsifier emulsification by Resins, epoxy, and the consumption of reactive emulsifier is the 10-18% of weight epoxy, the 12-15% of proper consumption.This reactive emulsifier by Resins, epoxy with have surface-active polyether Glycols and in the presence of lewis acid catalyst, react the polymer-type emulsifying agent that generation, end group are respectively epoxy group(ing) and hydroxyl, solid content is 40-50%; Resins, epoxy wherein can be bisphenol A-type lower molecular weight or high molecular expoxy resin, and polyether Glycols comprises polyoxyethylene glycol, polypropylene glycol, polytetramethylene glycol or its multipolymer etc.Aqueous epoxy resin curing agent is through end-blocking, addition, salify process modification and the water soluble solid agent that obtains by polyethylene polyamine.
Among the present invention, above-mentioned epoxy resin latex (first component) and aqueous epoxy resin curing agent (component B), the mol ratio preparation by epoxy group(ing) and amine hydrogen 1.2:1-1:1.2 gets aqueous epoxide resin paint varnish.Wherein can add proper quantity of defoaming agent in the first component, the bubble that generates when mixing to eliminate.The defoamer that adds can be SPA-202 (China), EGITAN760 (German Munzing company) etc.
The preparation method of the aqueous epoxide resin paint that the present invention proposes is as follows:
1, preparation reactive emulsifier
Because Resins, epoxy is height butyrous system (HLB=3), therefore its emulsification is relatively more difficult, emulsifying agent with single active center commonly used often can not obtain stable epoxy resin latex, and this emulsifying agent that adds remains in the filming after the curing water-fastly to what film, and the chemical-resistant influence is bigger.
The reactive emulsifier that the present invention uses, be by Resins, epoxy with have a surfactivity, can react in the presence of lewis acid catalyst with the polyether Glycols of epoxy reaction and generate again, the mol ratio of Resins, epoxy and polyether Glycols is 1.2:1-1:1.2, be 1:1 preferably, temperature of reaction is controlled at 90-100 ℃, and the reaction times is 4-6 hour.Formed reactive emulsifier is the water white solid, and is soluble in water.For ease of using, reaction is dissolved in water after finishing, and solid content is 40-50%, and products obtained therefrom is a clear solution, viscosity 1,000-1,500mPa.s.
Above-mentioned polyether Glycols comprises polyoxyethylene glycol, polypropylene glycol, polytetramethylene glycol or its multipolymer etc.The reactive emulsifier that generates with Resins, epoxy reaction back is the emulsifying agent of polymer-type, and molecular weight is very high, contains surface-active polyether segment in the molecular chain, and polyether segment and the alternately arrangement of Resins, epoxy segment, and promptly hydrophilic hydrophobic segment is alternately arranged.Have many surface-active hydrophilic polyether segments that have on the molecular chain of such reactive emulsifier, they are surfactivity centers.Different with the emulsifying agent at traditional single surfactivity center, it belongs to the Polymerizable Emulsifier in multilist face active centre.They become horizontal rather than vertical absorption on disperse phase epoxy particles surface when emulsion epoxy resin, can form very firm absorption protective layer and prevent particle aggregation, thereby can form highly stable epoxy resin latex.
The not end of the reactive emulsifier molecule that the reaction of Resins, epoxy and polyether Glycols generates has epoxy group(ing), so it can participate in the curing reaction of epoxy curing agent, becomes a part of solidifying the back corsslinking molecular.So claim that it is a reactive emulsifier, the type emulsifying agent is different with adding, it is less to the influence of film performance.
2 preparation epoxy resin latexes
No matter be low-molecular-weight epoxy resin, as E-51, E-48, or high molecular expoxy resin can use reactive emulsifier emulsification as E-20.
Because the viscosity of Resins, epoxy is very high, generally need to add the small amounts of co-solvents dissolving, reduce viscosity, be convenient to emulsification.Cosolvent can adopt the ethers solution to Air quality harmless (NHAP), as propylene glycol monomethyl ether, and propylene glycol butyl ether, 1-Methoxy-2-propyl acetate etc.To low-molecular-weight epoxy resin, can add the cosolvent dissolving of its 25-35% weight; To high molecular expoxy resin, can add the cosolvent dissolving of its 50-60% weight.But the content of cosolvent 5-7% only mainly is decomposition media with water in finished product.
The add-on of reactive emulsifier also has very big influence to stability of emulsion, and more suitable add-on is the 12-15% of weight epoxy.
The preparation of emulsion can be adopted homogenizer, carries out with phase inversion technique.Promptly earlier reactive emulsifier is joined and go in the dissolved epoxy resin solution, under high-speed stirring, slowly add quantitative water.It when system begins the water-in-oil system.Along with the adding of water, viscosity rises, and when the water yield is added to system generation phase reversion when a certain amount of, system viscosity descends, and is the oil-in-water system from the water-in-oil system transition promptly, becomes stable oil-in-water-type epoxy resin latex, and solid content is 40-50%.
Another kind method is to adopt the high pressure homogenizer, promptly atomizes through a nozzle at high pressure (reaching as high as 50MPa) following dissolved epoxy solution, water emulsifier and water, forms stable epoxy resin latex, and solid content is 40-50%.
3. preparation aqueous epoxy resin curing agent
Double-component aqueous epoxypaint requires at room temperature to solidify.Polyethylene polyamine and adduct thereof are the self-vulcanizing epoxy curing agents of using always, it is applicable to the solvent-borne type system and is not suitable for the water-base epoxy system, because it can not be dispersed in and form stable dispersion in the epoxy resin latex, cause the destruction of emulsion on the contrary, two are separated, coating curing is bad, even can not solidify.
The solidifying agent that uses in the water-base epoxy system must satisfy following condition:
1. compatible with epoxy resin latex, can be evenly dispersed in the emulsion that form uniformly can be in treasured temperature film forming solidified dispersion.
2. with Resins, epoxy consistency is preferably arranged behind the moisture evaporation in emulsion, can form the homogeneous wet film, thereby can fully and fully solidify, obtain filming of excellent property.
3. the speed of response with Resins, epoxy is moderate, to guarantee enough working lives (2-4 hour).
Satisfy above requirement, need polyethylene polyamine is carried out modification, the modified technique step is:
(1) end-blocking
Polyethylene polyamine can adopt diethylenetriamine, triethylene tetramine, different Fu Er ketone diamines etc.Their end group contains primary amine hydrogen, and the reactive behavior of they and epoxy group(ing) is higher than secondary amine hydrogen, therefore will prolong working life, primary amine hydrogen is sealed with mono-epoxy compounds.
Mono-epoxy compounds can adopt the aliphatic group glycidyl ethers, as the butyl glycidyl ethers; The aryl glycidyl ethers, as the phenyl glycidyl ethers, tolyl glycidyl ethers etc.
The mol ratio of polyethylene polyamine and mono-epoxy compounds is 1:1.2-1.2:1 during reaction, and temperature of reaction is controlled at 55-65 ℃, reaction times 100-150 minute.Because reaction should add mono-epoxy compounds for thermopositive reaction in polyethylene polyamine in batches, prevent to run material.
(2) addition
Polyethylene polyamine and epoxy resin compatibility are bad, by with it and diepoxides addition, introduce the Resins, epoxy segment in molecule, can improve the consistency with Resins, epoxy.
Diepoxides can adopt bisphenol A type epoxy resin, as E-51, and E-20 etc.The proportioning of raw material is that the mol ratio of end-blocking product and epoxy compounds is 1.8:1-2.2:1, and temperature of reaction is controlled at 90-100 ℃, time 1-2 hour.Reactor has reflux.Do not contained primary amine hydrogen in the solidifying agent that makes thus, but still had reactive hydrogen to exist, be secondary amine hydrogen, thereby its reactive behavior is reduced, helped prolonging working life.Simultaneously owing in molecule, introduced the Resins, epoxy segment, the consistency of it and Resins, epoxy is improved.
For reducing the viscosity of reactant, in the addition reaction system, also can add small amounts of co-solvents, ether solvent as described above.
(3) salify
The necessary salify of product after end-blocking and addition improves its wetting ability, just can become water miscible solidifying agent, can be evenly dispersed in the epoxy resin latex.
Salify adopts organic acid, and as acetic acid, the equivalence ratio of remaining amine hydrogen is 1:3.5-1:4.5 after it and end-blocking and the addition, be that the salify rate is about 25%, can reach hydrophilic-lipophilic balance preferably like this, can be dispersed in the emulsion, not only with epoxy resin latex in resin but also consistency preferably.Salt-forming reaction was carried out 50-70 minute at 85-95 ℃.Salt-forming reaction adds entry after finishing, and gets solidifying agent, and solid content can be 30-50%, is light yellow viscous liquid.
Preparation aqueous epoxide resin paint varnish
The first component: epoxy resin latex adds proper quantity of defoaming agent, and as home-made defoamer SPA-202, the EGITAN 760 of the German Munzing company of import fully disperses the back as the first component.
Second is formed: aqueous epoxy resin curing agent
The preparation of varnish: the mol ratio of epoxy group(ing) and amine hydrogen is 1.2:1-1:1.2 in first component and the component B.
The performance of gained coating:
1, the stability of epoxy resin latex
1) centrifugal stability: 2000 rev/mins, 30 minutes not stratified
2) stability in storage: not breakdown of emulsion layering of emulsion in 6 months
3) median size:<1 μ m.
2, working life: 2-4 hour (glossiness drops to 60%)
3, wear resistance 750 grams 1000 change weightlessness<0.05g
4, hardness of film (fork method):〉0.6 (GB/T 1730-93)
5, glossiness〉80% (GB/T 1743-79)
6, water tolerance: 25 ℃, 24 hours: non-foaming, do not peel off (GB/T 1733)
Embodiment
The invention is further illustrated by the following examples.
Embodiment 1
(1) preparation of reactive emulsifier (I)
On four neck flasks, be equipped with whipping appts, thermometer and towards nitrogen conduit, flask heats in water-bath, with 200 gram polyoxyethylene glycol (0.05mol, molecular weight 4000) and 50g E-20 Resins, epoxy add flask, feed the nitrogen excluding air, be heated to 70~80 ℃ then, add an amount of lewis acid catalyst again, temperature of reaction system rises.Control reaction temperature is 90~100 ℃, sustained reaction 6 hours.Add 250g water again, be stirred to product and dissolve fully, obtain the water white settled solution.
Solid content 50%, viscosity are about 1000mPas.
(2) preparation of epoxy resin latex
In the 800ml beaker, add 200g E-51 Resins, epoxy, start dispersion machine and stir at a slow speed, add 60g two 2-ethoxyethanols.After Resins, epoxy dissolves fully, add 60g reactive emulsifier (I) again, stir fully and disperse.
Under high-speed stirring, progressively add 200g water, stirred 10~15 minutes, obtain the stable epoxy resin latex of oyster white.
Solid content: 50%
Viscosity: about 400mPas
Epoxy equivalent (weight): 494.
The stability of epoxy resin latex: centrifugal stability: 2000 rev/mins, 30 minutes not stratified.
(3) aqueous epoxy resin curing agent is synthetic
A. end-blocking
On three-necked bottle, equip whipping appts, thermometer and reflux.Add 145g triethylene tetramine (TETA, 1 mole) earlier, add 130 gram butyl glycidyl ethers more in batches, control reaction temperature is 60 ℃, reacts 2 hours, and product is light yellow viscous liquid.
B. addition
Three necks and in adding E-20 Resins, epoxy 42g.Add the 14g dihydroxypropane single-ether again, be heated to 80 ℃, resin is dissolved fully.
Resin solution is cooled to about 40 ℃, adds the above-mentioned end-blocking product of 30g again, slowly heat up, control and maintenance temperature of reaction are about 90 ℃, react 2 hours.
C. salify
5g acetic acid is joined in the reactant, and holding temperature was reacted 1 hour about 90 ℃ again,
E. dissolving
In the time of 90 ℃, add 175g water, be stirred to the formation yellow solution.
Solid content: about 28%
Viscosity: about 3,000mPas
Amine hydrogen equivalent: 800
(4) preparation of double-component aqueous Resins, epoxy floor varnish
The first component: add 0.2% EGITAN 760 defoamers in the epoxy resin latex, height stirs and is uniformly dispersed.
Second component: aqueous epoxy resin curing agent.
With the first component: the mixed of second component=5:8 (the about 1:1 of mol ratio), stir by hand, be coated on sheet glass and the tinplate sheet with brush.Form transparent wet film behind the moisture evaporation, about 90 minutes of surface drying time, film performance:
Hardness (fork method) 0.70
Wear resistance (750 grams 1000 change weightless) 0.014g
Glossiness (60 °) 80%
Water tolerance, 25 °, 24 hours: non-foaming, do not peel off.
Embodiment 2
(1) preparation of reactive emulsifier (I)
On four neck flasks, be equipped with whipping appts, thermometer and towards nitrogen conduit, flask heats in water-bath, with 50 gram polyoxyethylene glycol (0.05mol, molecular weight 1000) and 50g E-20 Resins, epoxy add flask, feed the nitrogen excluding air, be heated to 70~80 ℃ then, add an amount of lewis acid catalyst again, temperature of reaction system rises.Control reaction temperature is 90~100 ℃, sustained reaction 6 hours.Add 100g water again, be stirred to product and dissolve fully, obtain the water white settled solution.
Solid content 50%, viscosity are about 800mPas.
(2) preparation of epoxy resin latex
In the 800ml beaker, add 200g E-20 Resins, epoxy, start dispersion machine and stir at a slow speed, add 100g two 2-ethoxyethanols.After Resins, epoxy dissolves fully, add 60g reactive emulsifier (I) again, stir fully and disperse.
Under high-speed stirring, progressively add 160g water, stirred 10~15 minutes, obtain the stable epoxy resin latex of oyster white.
Solid content: 50%
Viscosity: about 800mPas
Epoxy equivalent (weight): 1300
The stability of epoxy resin latex: centrifugal stability: 1000 rev/mins, 30 minutes not stratified;
2000 rev/mins, layering in 15 minutes;
(3) aqueous epoxy resin curing agent is synthetic
A. end-blocking
On three-necked bottle, equip whipping appts, thermometer and reflux.Add 145g triethylene tetramine (TETA, 1 mole) earlier, add 158 gram phenyl glycidyl ethers more in batches, control reaction temperature is 60 ℃, reacts 2 hours, and product is a light yellow liquid.
B. addition
Three necks and in adding E-20 Resins, epoxy 42g.Add the 14g dihydroxypropane single-ether again, be heated to 80 ℃, resin is dissolved fully.
Resin solution is cooled to about 40 ℃, adds the above-mentioned end-blocking product of 33g again, slowly heat up, control and maintenance temperature of reaction are about 90 ℃, react 2 hours.
C. salify
5g acetic acid is joined in the reactant, and holding temperature was reacted 1 hour about 90 ℃ again,
E. dissolving
In the time of 90 ℃, add 175g water, be stirred to the formation yellow solution.
Solid content: 28%
Viscosity: about 5,000mPas
Amine hydrogen equivalent: 800.
(4) preparation of double-component aqueous Resins, epoxy floor varnish
The first component: add 0.2% EGITAN 760 defoamers in the epoxy resin latex, height stirs and is uniformly dispersed.
Second component: aqueous epoxy resin curing agent.
With the first component: the mixed of second component=13:8 (the about 1:1 of mol ratio), stir by hand, be coated on sheet glass and the tinplate sheet with brush.Form transparent wet film behind the moisture evaporation, about 30 minutes of surface drying time, film performance:
Hardness (fork method) 0.45
Wear resistance (750 grams 1000 change weightless) 0.024g
Glossiness (60 °) 80%
Water tolerance, 25 °, 24 hours: non-foaming, do not peel off.