CN112794999A - Epoxy modified polyester emulsion and preparation method and application thereof - Google Patents
Epoxy modified polyester emulsion and preparation method and application thereof Download PDFInfo
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- CN112794999A CN112794999A CN202011611767.XA CN202011611767A CN112794999A CN 112794999 A CN112794999 A CN 112794999A CN 202011611767 A CN202011611767 A CN 202011611767A CN 112794999 A CN112794999 A CN 112794999A
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/91—Polymers modified by chemical after-treatment
- C08G63/914—Polymers modified by chemical after-treatment derived from polycarboxylic acids and polyhydroxy compounds
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/91—Polymers modified by chemical after-treatment
- C08G63/914—Polymers modified by chemical after-treatment derived from polycarboxylic acids and polyhydroxy compounds
- C08G63/916—Dicarboxylic acids and dihydroxy compounds
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D167/00—Coating compositions based on polyesters obtained by reactions forming a carboxylic ester link in the main chain; Coating compositions based on derivatives of such polymers
- C09D167/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
Abstract
The invention provides an epoxy modified polyester emulsion and a preparation method and application thereof, wherein the raw materials of the epoxy modified polyester emulsion comprise the combination of polyol, polybasic acid, epoxy resin, a cross-linking agent, a catalyst and a neutralizing agent in parts by weight; the cross-linking agent can react with the epoxy modified polyester prepolymer in the presence of the catalyst to obtain the epoxy modified polyester emulsion; the obtained epoxy modified polyester emulsion has the toughness of polyester and the cohesiveness of epoxy resin, has excellent adhesive force, physical and mechanical properties and chemical stability, is non-toxic and harmless, and meets the requirements of environmental protection.
Description
Technical Field
The invention belongs to the technical field of coatings, and particularly relates to an epoxy modified polyester emulsion and a preparation method and application thereof.
Background
The polyester macromolecule is formed by the esterification polycondensation of polyhydric alcohol and polybasic acid. The polyester resin has the advantages of good luster, high hardness, strong impact resistance, excellent electrical insulation and the like, and is an engineering plastic with excellent performance and wide application.
In recent years, with the increasing awareness of environmental protection, a dispersion system containing no volatile organic compounds has become the development direction of a novel polyester polymer material. Among them, the water-based polyester has advantages of high mechanical properties and environmental protection, so the research and development of the water-based polyester are increasingly paid attention by researchers. CN105295641A discloses a preparation method of a solvent-free waterborne polyester modified epoxy coating and the prepared coating, and the preparation method mainly comprises the following steps: reacting castor oil, isophthalic acid, adipic acid, diethylene glycol and ethylene glycol to prepare low-viscosity transparent carboxyl-containing polyester resin liquid; reacting carboxyl polyester resin liquid with epoxy resin according to the weight ratio of 3 (4-6) to prepare polyester modified epoxy resin; adding pigment, filler and carbon black, dispersing at a high speed for 15-18 min, adding a leveling agent and an active diluent, adjusting the viscosity and the solid content of the coating to 96%, and obtaining a finished coating which is suitable for long-acting corrosion prevention of hydraulic engineering, ships and offshore platforms, reducing VOC (volatile organic compounds) in construction, obtaining a thick film with the thickness of more than 200 mu m by one-time construction, and is suitable for construction and manual coating of various heating or non-heating special coating equipment, and reducing construction cost and maintenance cost. CN109721717A discloses a waterborne epoxy modified saturated polyester resin and a preparation method and application thereof; the preparation method comprises the following steps: contacting polyol and polybasic acid for reaction, and stopping the reaction until the acid value in the reaction system is less than 10mgKOH/g to obtain the terminal hydroxyl saturated polyester resin; contacting the hydroxyl-terminated saturated polyester resin with epoxy resin for reaction, and stopping the reaction until the epoxy value in a reaction system is less than 20mmol/kg to obtain epoxy modified saturated polyester resin; and (3) contacting the epoxy modified saturated polyester resin with polybasic acid anhydride for reaction, and stopping the reaction until the acid value in the reaction system is 20-60 mgKOH/g, so as to obtain the waterborne epoxy modified saturated polyester resin. The amino baking varnish prepared by using the modified polyester resin has the advantages of high film fullness, high glossiness, good adhesion, good toughness, good acid resistance and good alkali resistance. CN106047097A discloses a waterborne epoxy modified polyester board primer and a preparation method thereof. The waterborne epoxy modified polyester board primer comprises the following components in parts by weight: 40-50 parts of water-based epoxy modified polyester, 10-20 parts of amino resin, 5-10 parts of fluorocarbon resin, 10-15 parts of pigment slurry, 0.3-0.6 part of defoaming agent, 0.5-3 parts of thickening agent, 0.5-1 part of flatting agent, 0.1-0.5 part of wetting agent, 0.2-0.8 part of film forming agent, 0.5-1 part of anti-settling agent, 0.5-1 part of preservative and the balance of deionized water. The primer coating has the advantages of bright color, strong adhesive force, excellent corrosion resistance, high mechanical property, good durability and good self-cleaning property, and can meet different user requirements.
However, the molecular chain of the water-based polyester resin has unreacted carboxyl and hydroxyl, and the hydrophilic groups cause the defects of slow water volatilization, poor water resistance after a high molecular network structure is formed and the like in the using process of the resin, thereby limiting the practical application of the resin.
Therefore, the development of the epoxy modified polyester emulsion with low hydroxyl content and excellent water resistance and the preparation method thereof have important research significance and practical value.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide an epoxy modified polyester emulsion and a preparation method and application thereof, wherein the preparation raw materials of the epoxy modified polyester emulsion comprise a combination of polyol, polybasic acid, epoxy resin, a cross-linking agent, a catalyst and a neutralizing agent; by adding a cross-linking agent which has good compatibility with the polyester emulsion and can generate cross-linking reaction and adding a catalyst, the hydroxyl content in the polyester emulsion is reduced, and further the epoxy modified polyester emulsion with excellent water resistance is obtained.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the invention provides an epoxy modified polyester emulsion, which comprises the following raw materials in parts by weight: 10-25 parts of polyol, 15-35 parts of polybasic acid, 5-16 parts of epoxy resin, 0.05-5 parts of cross-linking agent, 0.0005-0.022 parts of catalyst and 0.05-5 parts of neutralizing agent.
The polyol can be 12, 14, 16, 18, 20, 22, or 24 parts by weight, and the like.
The polybasic acid may be 17 parts by weight, 19 parts by weight, 21 parts by weight, 25 parts by weight, 27 parts by weight, 29 parts by weight, 31 parts by weight, 33 parts by weight, or the like.
The epoxy resin may be 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, or the like.
The crosslinking agent may be 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, or 4.5 parts by weight, or the like.
The catalyst may be 0.0007, 0.0009, 0.0011, 0.0013, 0.0015, 0.0017 or 0.0021, 0.005, 0.009, 0.01, 0.015 or 0.02 parts by weight, etc.
The neutralizing agent may be 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, or 4.5 parts by weight, or the like.
The raw materials of the epoxy modified polyester emulsion provided by the invention comprise a combination of polyol, polybasic acid, epoxy resin, a cross-linking agent, a catalyst and a neutralizing agent; the cross-linking agent can perform cross-linking reaction with hydroxyl in the polyester emulsion in the presence of the catalyst, so that the content of the hydroxyl in the polyester emulsion can be reduced, and the water resistance of the polyester emulsion is improved.
Preferably, the epoxy-modified polyester emulsion has a solids content of 25 to 45%, such as 27%, 29%, 31%, 33%, 35%, 38%, 41% or 44%, and the specific values therebetween are limited by space and for the sake of brevity and are not exhaustive of the specific values included in the ranges.
Preferably, the acid value of the epoxy modified polyester emulsion is 15 to 30mgKOH/g, such as 17mgKOH/g, 19mgKOH/g, 21mgKOH/g, 23mgKOH/g, 25mgKOH/g, 27mgKOH/g or 29mgKOH/g, and the specific values therebetween are not exhaustive, and for brevity and clarity, the invention is not intended to be limited to the specific values included in the scope.
Preferably, the polyol comprises any one of neopentyl glycol, diethylene glycol, glycerol, trihydroxymethyl ethane or pentaerythritol or a combination of at least two thereof.
Preferably, the polybasic acid comprises any one or a combination of at least two of phthalic acid, isophthalic acid, terephthalic acid, trimesic acid or phthalic anhydride.
Preferably, the epoxy resin comprises any one of E-20 epoxy resin, E-44 epoxy resin or E-12 epoxy resin or a combination of at least two of the same.
Preferably, the raw material of the epoxy modified polyester emulsion further comprises monocarboxylic acid.
Preferably, the content of the monocarboxylic acid in the raw material of the epoxy-modified polyester emulsion is 2 to 15 parts by weight, such as 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, 10 parts by weight, 12 parts by weight or 14 parts by weight, and specific points therebetween are not exhaustive, and the invention is not limited to the specific points included in the range for brevity.
Preferably, the monocarboxylic acid comprises dihydroxymethylpropionic acid.
Preferably, the cross-linking agent is an aldehyde compound, preferably glutaraldehyde.
Preferably, the catalyst is sulfonated polysulfone.
Preferably, the sulfonated polysulfone has an acid content of 2.2 to 3.1mmol/g, such as 2.3mmol/g, 2.4mmol/g, 2.5mmol/g, 2.6mmol/g, 2.7mmol/g, 2.8mmol/g, 2.9mmol/g or 3mmol/g, and the specific values therebetween are limited in space and for the sake of brevity and the invention is not exhaustive.
Preferably, the neutralizing agent is an amine compound, and further preferably triethylamine and/or ethanolamine.
In a second aspect, the present invention provides a method for preparing the epoxy modified polyester emulsion according to the first aspect, wherein the method comprises the following steps:
(1) reacting polyalcohol with polybasic acid to obtain a polyester prepolymer;
(2) adding epoxy resin into the polyester prepolymer obtained in the step (1) for reaction to obtain an epoxy modified polyester prepolymer;
(3) reacting the epoxy modified polyester prepolymer obtained in the step (2), a cross-linking agent and a catalyst to obtain epoxy modified polyester stock solution;
(4) and (4) reacting the epoxy modified polyester stock solution obtained in the step (3) with a neutralizing agent to obtain the epoxy modified polyester emulsion.
The preparation method of the epoxy modified polyester emulsion comprises four steps, firstly, carrying out esterification reaction on polyhydric alcohol and polybasic acid to obtain a polyester prepolymer after the reaction is finished; then adding epoxy resin into the polyester prepolymer for modification reaction to obtain an epoxy modified polyester prepolymer; reacting the obtained epoxy modified polyester prepolymer with a cross-linking agent in the presence of a catalyst, wherein hydroxyl in the epoxy modified prepolymer can be changed into aldehyde group; and finally adding a neutralizing agent into the system for reaction to obtain the epoxy modified polyester emulsion.
Preferably, the reaction of step (1) is carried out under heated conditions.
Preferably, the heating method comprises the following steps: heating the system from room temperature to 70-80 deg.C (such as 71 deg.C, 72 deg.C, 73 deg.C, 74 deg.C, 75 deg.C, 76 deg.C, 77 deg.C, 78 deg.C or 79 deg.C), maintaining for 5-10 min (such as 5.5min, 6min, 6.5min, 7min, 7.5min, 8min, 8.5min, 9min or 9.5 min), heating to 110-120 deg.C (such as 111 deg.C, 112 deg.C, 113 deg.C, 114 deg.C, 115 deg.C, 116 deg.C, 117 deg.C, 118 deg.C or 119 deg.C), maintaining for 20-30 min (such as 21min, 22min, 23min, 24min, 25min, 26min, 27min, 28min or 29 min), heating to 210-220 deg.C (such as 211 deg.C, 212 deg.C, 213 deg.C, 215 deg.C, 216 deg.C, 217 deg.C, 218 deg.C or 219 deg.C), and maintaining for 2-3 h (such as 2.1h, 2.2.2.2.2.
As a preferred technical scheme of the present invention, the heating manner of the reaction in step (1) of the present invention is stepwise temperature rise, which has the advantage that the melting points of the raw materials are different, so that the reaction activities are different, and the stepwise temperature rise can allow the raw materials with low melting points and high reaction activities to perform limited reaction, and then dehydrate, gradually raise the temperature, gradually dehydrate, and is beneficial to the stability of dehydration; and the low melting point limited reaction can avoid the loss caused by volatilization of the low melting point raw material due to too high temperature of the bulb.
Preferably, the rate of temperature rise is 5-15 ℃/h, such as 6 ℃/h, 7 ℃/h, 8 ℃/h, 9 ℃/h, 10 ℃/h, 11 ℃/h, 12 ℃/h, 13 ℃/h or 14 ℃/h, independently, and the specific values therebetween, limited to space and for the sake of brevity, the invention is not exhaustive list of the specific values included in the ranges.
Preferably, the reaction in step (1) is carried out under the protection of inert gas, more preferably under the protection of nitrogen.
Preferably, the reaction of step (1) is finished and then the reaction further comprises a step of removing water.
Preferably, a water separating agent is further added in the reaction in the step (1), and the water removing also comprises a water separating agent.
Preferably, the water removal in step (1) is performed by a vacuum method.
Preferably, the acid value of the polyester emulsion in step (1) is 40-70 mgKOH/g, such as 43mgKOH/g, 46mgKOH/g, 49mgKOH/g, 51mgKOH/g, 54mgKOH/g, 57mgKOH/g, 60mgKOH/g, 63mgKOH/g, 66mgKOH/g or 69mgKOH/g, and the specific values therebetween are not exhaustive, and the invention is not limited to the specific values included in the range for brevity and conciseness.
Preferably, the reaction temperature in step (2) is 70-90 ℃, such as 72 ℃, 74 ℃, 76 ℃, 78 ℃, 80 ℃, 82 ℃, 84 ℃, 86 ℃ or 88 ℃, and the specific values therebetween are limited by space and for the sake of brevity, and the invention is not exhaustive of the specific values included in the range.
Preferably, the epoxy resin is added in step (2) in a dropwise manner.
Preferably, the dropping time is 3-5 h, such as 3.2h, 3.4h, 3.6h, 3.8h, 4h, 4.2h, 4.4h, 4.6h or 4.8h, and the specific values therebetween are limited by space and for the sake of brevity, and the invention is not exhaustive.
Preferably, the method further comprises a step of keeping the temperature after the reaction in the step (2) is finished.
Preferably, the incubation time is 4-6 h, such as 4.2h, 4.4h, 4.6h, 4.8h, 5h, 5.2h, 5.4h, 5.6h or 5.8h, and the specific values therebetween are not exhaustive, and for the sake of brevity.
Preferably, the reaction temperature in step (3) is 50-70 ℃, such as 52 ℃, 54 ℃, 56 ℃, 58 ℃, 60 ℃, 62 ℃, 64 ℃, 66 ℃ or 68 ℃, and the specific values therebetween are limited by space and for the sake of brevity, and the invention is not exhaustive of the specific values included in the range.
Preferably, the reaction time in step (3) is 4-6 h, such as 4.2h, 4.4h, 4.6h, 4.8h, 5h, 5.2h, 5.4h, 5.6h or 5.8h, and the specific values therebetween are not exhaustive, and for brevity and clarity, the invention is not intended to be limited to the specific values included in the range.
Preferably, the reaction temperature in step (4) is 30-50 ℃, for example, 32 ℃, 34 ℃, 36 ℃, 38 ℃, 40 ℃, 42 ℃, 44 ℃, 46 ℃ or 48 ℃, and the specific values therebetween are limited by space and for the sake of brevity, and the invention is not exhaustive of the specific values included in the range.
Preferably, the reaction in the step (4) is carried out under the condition of stirring, and further preferably under the condition of stirring at the rotating speed of 700-900 r/min (720r/min, 740r/min, 760r/min, 780r/min, 800r/min, 820r/min, 840r/min, 860r/min or 880r/min, and the like).
Preferably, the reaction time in step (4) is 0.5-2 h, such as 0.6h, 0.7h, 0.8h, 0.9h, 1h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h or 1.9h, and the specific values therebetween are limited by space and for brevity, and the invention is not exhaustive of the specific values included in the range.
Preferably, deionized water is also added to the reaction in step (4).
As a preferred technical scheme, the preparation method comprises the following steps:
(1) heating polyol and polybasic acid under the conditions of inert gas protection and water separating agent addition, and vacuumizing to remove water and water separating agent to obtain a polyester prepolymer with an acid value of 40-70 mgKOH/g; the heating method comprises the following steps: heating the system from normal temperature to 70-80 ℃ according to a heating rate of 5-15 ℃/h, preserving heat for 5-10 min, heating to 110-120 ℃ according to a heating rate of 5-15 ℃/h, preserving heat for 20-30 min, finally heating to 210-220 ℃ according to a heating rate of 5-15 ℃/h, and preserving heat for 2-3 h;
(2) dripping epoxy resin into the polyester prepolymer obtained in the step (1), reacting for 4-6 h at 70-90 ℃, and preserving heat for 4-6 h to obtain an epoxy modified polyester prepolymer; the dripping time is 3-5 h;
(3) reacting the epoxy modified polyester prepolymer obtained in the step (2), a cross-linking agent and a catalyst at 50-70 ℃ for 4-6 h to obtain an epoxy modified polyester stock solution;
(4) and (3) reacting the epoxy modified polyester stock solution obtained in the step (3), a neutralizing agent and deionized water for 0.5-1.5 h under the stirring conditions of 30-50 ℃ and 700-900 r/min of rotation speed, thus obtaining the epoxy modified polyester emulsion.
In a third aspect, the present invention provides a use of the epoxy modified polyester emulsion of the first aspect in a coating.
Preferably, the coating is a baking varnish.
Compared with the prior art, the invention has the following beneficial effects:
(1) the epoxy modified polyester emulsion provided by the invention is prepared by reacting polyalcohol and polybasic acid to generate polyester, then modifying the polyester by using epoxy resin to obtain an epoxy modified polyester prepolymer, and finally reacting the epoxy modified polyester prepolymer with a cross-linking agent in the presence of a catalyst to obtain the epoxy modified polyester emulsion; the epoxy modified polyester emulsion has the toughness of polyester and the cohesiveness of epoxy resin, has excellent adhesive force, physical and mechanical properties and chemical stability, is non-toxic and harmless, and meets the requirements of environmental protection; compared with the epoxy modified polyester emulsion provided by the prior art, the epoxy modified polyester emulsion has higher water resistance, chemical stability and weather resistance.
(2) The epoxy modified polyester emulsion provided by the invention is milky in emulsion state, the pencil hardness can reach 2H, the drying time of 1000g is only 12 days, the impact resistance is 47-53 cm, the salt water resistance can reach 5-10 days without foaming, and the storage stability is more than 3-6 months.
Detailed Description
The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.
Example 1
An epoxy modified polyester emulsion, the acid value is 20mgKOH/g, the solid content is 31%;
the preparation method comprises the following steps:
(1) heating 100g of neopentyl glycol, diethylene glycol, glycerol and trihydroxymethyl ethane in a mass ratio of 20:30:40:10 with 150g of phthalic acid, isophthalic acid, terephthalic acid, trimesic acid and dihydroxymethyl propionic acid in a mass ratio of 20:20:20:30:10 under the protection of nitrogen gas and under the condition of adding 80mL of toluene, heating the system from normal temperature to 70 ℃ at a heating rate of 10 ℃/h, preserving heat for 10min, heating to 120 ℃ at a heating rate of 10 ℃/h, preserving heat for 30min, finally heating to 220 ℃ at a heating rate of 10 ℃/h, preserving heat for 3h, and then vacuumizing to remove water and toluene to obtain a polyester prepolymer with an acid value of 50 mgKOH/g;
(2) dripping 50g E-20 epoxy resin into the polyester prepolymer obtained in the step (1) at the temperature of 80 ℃, keeping the temperature for 5 hours to obtain an epoxy modified polyester prepolymer;
(3) reacting the epoxy modified polyester prepolymer obtained in the step (2), 5g of glutaraldehyde and 1g of sulfonated polysulfone at 60 ℃ for 5 hours to obtain epoxy modified polyester stock solution;
(4) and (3) reacting the epoxy modified polyester stock solution obtained in the step (3) with 15mL of 10% triethylamine aqueous solution by mass at 40 ℃ under the stirring condition of the rotating speed of 800r/min for 2h to obtain the epoxy modified polyester emulsion.
Example 2
An epoxy-modified polyester emulsion which is different from example 1 only in that the E-20 epoxy resin in step (2) is replaced by the E-12 epoxy resin, and the other components, the amounts and the steps are the same as those in example 1.
Example 3
An epoxy-modified polyester emulsion which differs from example 1 only in that glutaraldehyde is used in step (3) in an amount of 2.5g and sulfonated polysulfone is used in an amount of 0.5 g; e-12 epoxy resin was used in place of E-20 epoxy resin in step (2), and the other components, amounts and steps were the same as in example 1.
Example 4
An epoxy modified polyester emulsion having an acid value of 30 mgKOH/g; the solid content is 37 percent;
the preparation method comprises the following steps:
(1) heating 250g of neopentyl glycol, diethylene glycol, glycerol and trihydroxymethyl ethane in a mass ratio of 20:30:40:10 and 350g of phthalic acid, isophthalic acid, terephthalic acid, trimesic acid and dihydroxymethyl propionic acid in a mass ratio of 20:20:20:30:10 under the protection of nitrogen gas and under the condition of adding 100mL of toluene, heating the system from normal temperature to 80 ℃ at a heating rate of 15 ℃/h, preserving heat for 5min, heating to 110 ℃ at a heating rate of 15 ℃/h, preserving heat for 20min, finally heating to 210 ℃ at a heating rate of 15 ℃/h, preserving heat for 2h, and then vacuumizing to remove water and toluene to obtain a polyester prepolymer with an acid value of 70 mgKOH/g;
(2) at 70 ℃, 160g E-20 epoxy resin is dripped into the polyester prepolymer obtained in the step (1), the dripping time is 3 hours, and the heat preservation is carried out for 4 hours, so as to obtain an epoxy modified polyester prepolymer;
(3) reacting the epoxy modified polyester prepolymer obtained in the step (2), 50g of glutaraldehyde and 0.22g of sulfonated polysulfone at 50 ℃ for 4 hours to obtain epoxy modified polyester stock solution;
(4) and (3) reacting the epoxy modified polyester stock solution obtained in the step (3) with 25mL of 10% triethylamine aqueous solution by mass at the temperature of 30 ℃ and the rotating speed of 700r/min under the stirring condition for 0.5h to obtain the epoxy modified polyester emulsion.
Example 5
An epoxy modified polyester emulsion having an acid value of 30 mgKOH/g; the solid content is 41%;
the preparation method comprises the following steps:
(1) heating 150g of neopentyl glycol, diethylene glycol, glycerol and trihydroxymethyl ethane in a mass ratio of 20:30:40:10 and 2000g of phthalic acid, isophthalic acid, terephthalic acid, trimesic acid and dihydroxymethyl propionic acid in a mass ratio of 20:20:20:30:10 under the protection of inert gas and under the condition of adding 90mL of toluene, heating the system from normal temperature to 75 ℃ at a heating rate of 12 ℃/h, keeping the temperature for 8min, heating to 115 ℃ at a heating rate of 12 ℃/h, keeping the temperature for 25min, heating to 215 ℃ at a heating rate of 12 ℃/h, keeping the temperature for 2.5h, and then vacuumizing to remove water and toluene to obtain a polyester prepolymer with an acid value of 60 mgKOH/g;
(2) at 90 ℃, dropwise adding 100g E-20 epoxy resin into the polyester prepolymer obtained in the step (1), wherein the dropwise adding time is 3 hours, and keeping the temperature for 4 hours to obtain an epoxy modified polyester prepolymer;
(3) reacting the epoxy modified polyester prepolymer obtained in the step (2), 25g of glutaraldehyde and 0.11g of sulfonated polysulfone at 70 ℃ for 6 hours to obtain epoxy modified polyester stock solution;
(4) and (3) reacting the epoxy modified polyester stock solution obtained in the step (3) with 20mL of ethanolamine aqueous solution with the mass percentage of 10% under the stirring condition of 35 ℃ and the rotating speed of 750r/min for 1h to obtain the epoxy modified polyester emulsion.
Example 6
An epoxy-modified polyester emulsion which is different from the emulsion in example 1 only in that the heating in step (1) is carried out by raising the temperature of the system from normal temperature to 220 ℃ at a rate of 10 ℃/h, and other components, amounts and steps are the same as those in example 1. Comparative example 1
An epoxy-modified polyester stock solution which differs from example 1 only in that the epoxy-modified polyester stock solution was obtained without carrying out the step (4), and the other components, amounts and steps were the same as in example 1.
And (3) performance testing:
the epoxy modified polyester emulsions obtained in examples 1 to 6 and the epoxy modified polyester stock solution obtained in comparative example 1 were tested for emulsion state, impact resistance, pencil hardness, salt water resistance, storage stability and drying time according to HG2239-91 "iron oxide red, zinc yellow and iron black epoxy ester primer", and the test results are shown in table 1:
TABLE 1
As can be seen from the test data in table 1,
the epoxy modified polyester emulsion provided by the invention has higher pencil hardness and shorter drying time, and can meet the requirements on impact resistance, salt water resistance and storage stability.
Specifically, the epoxy modified polyester emulsion obtained in examples 1 to 6 is milky white in emulsion state, has pencil hardness of 2H, has a drying time of 1000g of only 12 days, has impact resistance of 47 to 53cm, has salt water resistance of 5 to 10 days, and has storage stability of more than 3 to 6 months; the hardness of the epoxy modified polyester emulsion obtained in the prior art (comparative example 1) is only HB, and the drying time of 1000g needs 24 days, which shows that the epoxy modified polyester emulsion provided by the invention has higher water resistance.
The applicant states that the present invention is illustrated by the above examples to describe an epoxy modified polyester emulsion and its preparation method and application, but the present invention is not limited to the above examples, i.e. it does not mean that the present invention must rely on the above examples to be implemented. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.
Claims (10)
1. The epoxy modified polyester emulsion is characterized by comprising the following raw materials in parts by weight: 10-25 parts of polyol, 15-35 parts of polybasic acid, 5-16 parts of epoxy resin, 0.05-5 parts of cross-linking agent, 0.0005-0.022 parts of catalyst and 0.05-5 parts of neutralizing agent.
2. The epoxy modified polyester emulsion of claim 1, wherein the solid content of the epoxy modified polyester emulsion is 25-45%;
preferably, the acid value of the epoxy modified polyester emulsion is 15-30 mgKOH/g.
3. The epoxy modified polyester emulsion of claim 1 or 2, wherein the polyol comprises any one or a combination of at least two of neopentyl glycol, diethylene glycol, glycerol, trimethylolethane, or pentaerythritol;
preferably, the polybasic acid comprises any one or a combination of at least two of phthalic acid, isophthalic acid, terephthalic acid, trimesic acid or phthalic anhydride;
preferably, the epoxy resin comprises any one of E-20 epoxy resin, E-44 epoxy resin or E-12 epoxy resin or the combination of at least two of the epoxy resins;
preferably, the raw materials of the epoxy modified polyester emulsion further comprise monocarboxylic acid;
preferably, the content of monocarboxylic acid in the raw materials of the epoxy modified polyester emulsion is 2-15 parts by weight;
preferably, the monocarboxylic acid comprises dihydroxymethylpropionic acid.
4. The epoxy-modified polyester emulsion according to any one of claims 1 to 3, wherein the crosslinking agent is an aldehyde compound, preferably glutaraldehyde;
preferably, the catalyst is sulfonated polysulfone;
preferably, the acid content of the sulfonated polysulfone is 2.2-3.1 mmol/g;
preferably, the neutralizing agent is an amine compound, and further preferably triethylamine and/or ethanolamine.
5. A method for preparing the epoxy modified polyester emulsion according to any one of claims 1 to 4, wherein the method comprises the following steps:
(1) reacting polyalcohol with polybasic acid to obtain a polyester prepolymer;
(2) adding epoxy resin into the polyester prepolymer obtained in the step (1) for reaction to obtain an epoxy modified polyester prepolymer;
(3) reacting the epoxy modified polyester prepolymer obtained in the step (2), a cross-linking agent and a catalyst to obtain epoxy modified polyester stock solution;
(4) and (4) reacting the epoxy modified polyester stock solution obtained in the step (3) with a neutralizing agent to obtain the epoxy modified polyester emulsion.
6. The method according to claim 5, wherein the reaction of step (1) is carried out under heating;
preferably, the heating method comprises the following steps: heating the system from normal temperature to 70-80 ℃, preserving heat for 5-10 min, heating to 110-120 ℃, preserving heat for 20-30 min, finally heating to 210-220 ℃, and preserving heat for 2-3 h;
preferably, the heating rates are respectively and independently 5-15 ℃/h;
preferably, the reaction in step (1) is carried out under the protection of inert gas, more preferably under the protection of nitrogen;
preferably, the reaction of step (1) is finished and then a step of removing water is further included;
preferably, a water separating agent is further added in the reaction in the step (1), and the water removing also comprises a water removing agent;
preferably, the water removal of step (1) is performed by a vacuum method;
preferably, the acid value of the polyester prepolymer in the step (1) is 40-70 mgKOH/g.
7. The preparation method according to claim 5 or 6, wherein the temperature of the reaction in the step (2) is 70-90 ℃;
preferably, the epoxy resin in the step (2) is added dropwise;
preferably, the dripping time is 3-5 h;
preferably, the method also comprises a step of heat preservation after the reaction in the step (2) is finished;
preferably, the heat preservation time is 4-6 h.
8. The method according to any one of claims 5 to 7, wherein the temperature of the reaction in the step (3) is 50 to 70 ℃;
preferably, the reaction time in the step (3) is 4-6 h;
preferably, the temperature of the reaction in the step (4) is 30-50 ℃;
preferably, the reaction in the step (4) is carried out under the condition of stirring, and further preferably under the stirring condition with the rotating speed of 700-900 r/min;
preferably, the reaction time in the step (4) is 0.5-2 h;
preferably, deionized water is also added to the reaction in step (4).
9. The method according to any one of claims 5 to 8, characterized by comprising the steps of:
(1) heating polyol and polybasic acid under the conditions of inert gas protection and water separating agent addition, and vacuumizing to remove water and water separating agent to obtain a polyester prepolymer with an acid value of 40-70 mgKOH/g; the heating method comprises the following steps: heating the system from normal temperature to 70-80 ℃ according to a heating rate of 5-15 ℃/h, preserving heat for 5-10 min, heating to 110-120 ℃ according to a heating rate of 5-15 ℃/h, preserving heat for 20-30 min, finally heating to 210-220 ℃ according to a heating rate of 5-15 ℃/h, and preserving heat for 2-3 h;
(2) dripping epoxy resin into the polyester prepolymer obtained in the step (1), reacting for 4-6 h at 70-90 ℃, and preserving heat for 4-6 h to obtain an epoxy modified polyester prepolymer; the dripping time is 3-5 h;
(3) reacting the epoxy modified polyester prepolymer obtained in the step (2), a cross-linking agent and a catalyst at 50-70 ℃ for 4-6 h to obtain an epoxy modified polyester stock solution;
(4) and (3) reacting the epoxy modified polyester stock solution obtained in the step (3), a neutralizing agent and deionized water for 0.5-2 h under the stirring conditions of 30-50 ℃ and 700-900 r/min of rotation speed, thus obtaining the epoxy modified polyester emulsion.
10. Use of the epoxy-modified polyester emulsion according to any one of claims 1 to 4 in a coating;
preferably, the coating is a baking varnish.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040116599A1 (en) * | 2001-03-10 | 2004-06-17 | Fuchang Liu | Epoxy polyester, its emulsion and its preparation as well as water-base coatings containing the emusion |
| CN107099024A (en) * | 2017-06-21 | 2017-08-29 | 珠海市金团化学品有限公司 | A kind of waterborne polyester of water boiling resistance excellent performance and preparation method thereof |
| CN109721717A (en) * | 2017-10-31 | 2019-05-07 | 万华化学（广东）有限公司 | A kind of waterborne epoxy modified saturated polyester resin and its preparation method and application |
| CN109904500A (en) * | 2019-02-25 | 2019-06-18 | 四川大学 | A kind of side chain type sulfonated polysulfones/polyvinyl alcohol proton exchange membrane and preparation method thereof |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040116599A1 (en) * | 2001-03-10 | 2004-06-17 | Fuchang Liu | Epoxy polyester, its emulsion and its preparation as well as water-base coatings containing the emusion |
| CN107099024A (en) * | 2017-06-21 | 2017-08-29 | 珠海市金团化学品有限公司 | A kind of waterborne polyester of water boiling resistance excellent performance and preparation method thereof |
| CN109721717A (en) * | 2017-10-31 | 2019-05-07 | 万华化学（广东）有限公司 | A kind of waterborne epoxy modified saturated polyester resin and its preparation method and application |
| CN109904500A (en) * | 2019-02-25 | 2019-06-18 | 四川大学 | A kind of side chain type sulfonated polysulfones/polyvinyl alcohol proton exchange membrane and preparation method thereof |
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