CN112625204A - Curing agent for powder coating system and preparation method thereof - Google Patents
Curing agent for powder coating system and preparation method thereof Download PDFInfo
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- CN112625204A CN112625204A CN202011398498.3A CN202011398498A CN112625204A CN 112625204 A CN112625204 A CN 112625204A CN 202011398498 A CN202011398498 A CN 202011398498A CN 112625204 A CN112625204 A CN 112625204A
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- curing agent
- powder coating
- polybasic acid
- polyamine
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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
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/30—Low-molecular-weight compounds
- C08G18/34—Carboxylic acids; Esters thereof with monohydroxyl compounds
- C08G18/343—Polycarboxylic acids having at least three carboxylic acid groups
- C08G18/345—Polycarboxylic acids having at least three carboxylic acid groups having three carboxylic acid groups
-
- 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
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/30—Low-molecular-weight compounds
- C08G18/32—Polyhydroxy compounds; Polyamines; Hydroxyamines
- C08G18/3225—Polyamines
- C08G18/3228—Polyamines acyclic
-
- 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
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/30—Low-molecular-weight compounds
- C08G18/32—Polyhydroxy compounds; Polyamines; Hydroxyamines
- C08G18/3225—Polyamines
- C08G18/3237—Polyamines aromatic
- C08G18/324—Polyamines aromatic containing only one aromatic ring
-
- 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
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/30—Low-molecular-weight compounds
- C08G18/32—Polyhydroxy compounds; Polyamines; Hydroxyamines
- C08G18/3271—Hydroxyamines
- C08G18/3275—Hydroxyamines containing two hydroxy groups
-
- 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
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/30—Low-molecular-weight compounds
- C08G18/34—Carboxylic acids; Esters thereof with monohydroxyl compounds
- C08G18/341—Dicarboxylic acids, esters of polycarboxylic acids containing two carboxylic acid groups
-
- 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
- C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
- C09D5/03—Powdery paints
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Wood Science & Technology (AREA)
- Paints Or Removers (AREA)
- Polyurethanes Or Polyureas (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
A curing agent for a powder coating system and a preparation method thereof are disclosed, wherein the curing agent is obtained by jointly polymerizing polybasic acid and polyamine, and the polybasic acid comprises the following raw materials in parts by mole: 40-75 parts of diisocyanate, 10-25 parts of 1,3, 5-cyclohexane tricarboxylic acid and 5-10 parts of hexahydrophthalic acid; polyamine, calculated by mole, comprising: 5-30 parts of diethanolamine, 5-75 parts of diethylenetriamine and 10-55 parts of o-phenylenediamine; comprises the following steps: 1) adding polybasic acid into a reactor, adding a proper amount of ethanol as a solvent, and mixing and stirring; 2) adding polyamine into the polybasic acid, and carrying out reflux reaction; 3) distilling to remove the ethanol solvent, cooling the reaction mixture to room temperature, separating out crystals, carrying out vacuum filtration and drying to obtain the product. The curing speed of the invention is moderate, a coating film with excellent leveling property can be obtained, meanwhile, the slow curing speed is beneficial to the escape of small molecular compounds such as water molecules in the curing process, and pinholes are hardly generated when the invention is used for coating thick films with the thickness of more than 130 mu m.
Description
Technical Field
The invention relates to the technical field of curing agents, and particularly relates to a curing agent for a powder coating system and a preparation method thereof.
Background
The powder coating is 100% solid powder without organic solvent, which is different from oil-based coating and water-based coating, and the powder coating is a novel environment-friendly powder coating which does not use solvent or water as a dispersion medium but uses air as a dispersion medium, is uniformly coated on the surface of a workpiece and forms a coating film with special application after being heated. The method has the characteristics of no VOC, environmental protection, energy conservation, high construction efficiency, wide application range and the like.
Since the powder coating is suitable for various uses, it can be used in the fields of automobiles, home electric appliances, and the like, for example. Compared with conventional coatings, the powder coating composition is free of volatile solvents, thereby being more ecological, healthy and safe. Since no volatile solvents are released into the environment after thermal curing, powder coating compositions are increasingly used in the coating sector today where environmental standards are becoming more stringent.
At present, TGIC (triglycidyl isocyanurate) and HAA (beta-hydroxyalkylamide) are mainly used as curing agents for outdoor pure polyester powder coatings, but in recent years, TGIC is found to cause mutation on human germ cells and has heredity, most countries of European Union forbid the use of TGIC, and therefore, low-toxicity and environment-friendly HAA curing agents are widely used in practical application of the powder coating industry. However, the hydroxyl value of the beta-Hydroxyalkylamide (HAA) curing agent for the pure polyester resin powder coating system is high, generally 650-700mgKOH/g, the curing activity is high, the curing speed is high, the leveling property of the surface of a coating film is insufficient, the coating film with high leveling property is difficult to obtain, and pinholes are easy to appear when the coating film is used for thick film coating of more than 120 mu m, so the coating film cannot be used for thick film coating.
Disclosure of Invention
The invention aims to solve the technical problem of overcoming the defects in the prior art and provides a curing agent for a powder coating system, which has moderate curing speed and can obtain a coating film with excellent leveling property, and a preparation method thereof.
The technical scheme adopted by the invention for solving the technical problems is as follows: a curing agent for a powder coating system is obtained by jointly polymerizing polybasic acid and polyamine, wherein the polybasic acid comprises the following raw materials in parts by mole: 40-75 parts of diisocyanate, 10-25 parts of 1,3, 5-cyclohexane tricarboxylic acid and 5-10 parts of hexahydrophthalic acid.
Further, the polyamine comprises: diethanolamine, diethylenetriamine and o-phenylenediamine.
Further, the polyamine comprises the following components in parts by mole: 5-30 parts of diethanol amine, 5-75 parts of diethylenetriamine and 10-55 parts of o-phenylenediamine.
A process for preparing a curing agent for a powder coating system comprising the steps of: 1) Adding polybasic acid into a reactor, adding a proper amount of ethanol as a solvent, and mixing and stirring; 2) Adding polyamine into the polybasic acid, and carrying out reflux reaction; 3) Distilling to remove the ethanol solvent, cooling the reaction mixture to room temperature, separating out crystals, carrying out vacuum filtration and drying to obtain the product.
Further, in the step 3), adding a catalyst with a formula amount, and gradually raising the temperature under the protection of inert gas to react until no obvious distillate is evaporated out and the acid value of a reactant is less than 80 mgKOH/g; the reaction temperature does not exceed 225 ℃.
Further, the inert gas is nitrogen or argon.
Further, in the step 3), the reaction product is distilled off until the acid value of the reaction product is less than 80 mgKOH/g.
The invention has the advantages that the curing speed is moderate, a coating film with excellent leveling property can be obtained, meanwhile, the slow curing speed is beneficial to the escape of small molecular compounds such as water molecules in the curing process, and pinholes are hardly generated when the coating is used for coating thick films with the thickness of more than 130 mu m.
Detailed Description
The following examples are given to further illustrate the embodiments of the present invention:
example 1: a powder coating system used curing agent and its preparation method, it is polymerized together by polybasic acid and polyamine to get, the polybasic acid makes up the raw materials according to the molar part: 40 parts of diisocyanate, 25 parts of 1,3, 5-cyclohexane tricarboxylic acid and 10 parts of hexahydrophthalic acid; polyamine, calculated by mole, comprising: 10 parts of diethanol amine, 15 parts of diethylenetriamine and 25 parts of o-phenylenediamine.
A process for preparing a curing agent for a powder coating system comprising the steps of: 1) Adding polybasic acid into a reactor, adding a proper amount of ethanol as a solvent, and mixing and stirring; 2) Adding polyamine into the polybasic acid, and carrying out reflux reaction; 3) Adding a catalyst with the formula amount, gradually heating under the protection of inert gas nitrogen for reaction until no obvious distillate is evaporated out and the acid value of a reactant is less than 80 mgKOH/g; the reaction temperature is not more than 225 ℃, the ethanol solvent is removed by distillation, the reaction mixture is cooled to room temperature, crystals are separated out, and the product is obtained by vacuum filtration and drying.
Example 2: a powder coating system used curing agent and its preparation method, it is polymerized together by polybasic acid and polyamine to get, the polybasic acid makes up the raw materials according to the molar part: 65 parts of diisocyanate, 20 parts of 1,3, 5-cyclohexane tricarboxylic acid and 10 parts of hexahydrophthalic acid; polyamine, calculated by mole, comprising: 30 parts of diethanol amine, 35 parts of diethylenetriamine and 45 parts of o-phenylenediamine.
A process for preparing a curing agent for a powder coating system comprising the steps of: 1) Adding polybasic acid into a reactor, adding a proper amount of ethanol as a solvent, and mixing and stirring; 2) Adding polyamine into the polybasic acid, and carrying out reflux reaction; 3) Adding a catalyst with the formula amount, gradually raising the temperature under the protection of inert gas argon for reaction until no obvious distillate is evaporated out and the acid value of a reactant is less than 80 mgKOH/g; the reaction temperature is not more than 225 ℃, the ethanol solvent is removed by distillation, the reaction mixture is cooled to room temperature, crystals are separated out, and the product is obtained by vacuum filtration and drying.
Example 3: a powder coating system used curing agent and its preparation method, it is polymerized together by polybasic acid and polyamine to get, the polybasic acid makes up the raw materials according to the molar part: 60 parts of diisocyanate, 15 parts of 1,3, 5-cyclohexane tricarboxylic acid and 8 parts of hexahydrophthalic acid; polyamine, calculated by mole, comprising: 25 parts of diethanol amine, 65 parts of diethylenetriamine and 25 parts of o-phenylenediamine.
A process for preparing a curing agent for a powder coating system comprising the steps of: 1) Adding polybasic acid into a reactor, adding a proper amount of ethanol as a solvent, and mixing and stirring; 2) Adding polyamine into the polybasic acid, and carrying out reflux reaction; 3) Adding a catalyst with the formula amount, gradually raising the temperature under the protection of inert gas argon for reaction until no obvious distillate is evaporated out and the acid value of a reactant is less than 80 mgKOH/g; the reaction temperature is not more than 225 ℃, the ethanol solvent is removed by distillation, the reaction mixture is cooled to room temperature, crystals are separated out, and the product is obtained by vacuum filtration and drying.
Those not described in detail in the specification are well within the skill of the art.
The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and decorations can be made without departing from the technical principle of the present invention, and these modifications and decorations should also be regarded as being within the protection scope of the present invention.
Claims (8)
1. The curing agent for the powder coating system is characterized by being obtained by jointly polymerizing polybasic acid and polyamine, wherein the polybasic acid comprises the following raw materials in parts by mole: 40-75 parts of diisocyanate, 10-25 parts of 1,3, 5-cyclohexane tricarboxylic acid and 5-10 parts of hexahydrophthalic acid.
2. A curing agent for powder coating systems according to claim 1, wherein said polyamine comprises: diethanolamine, diethylenetriamine and o-phenylenediamine.
3. A curing agent for powder coating systems according to claim 2, wherein said polyamine comprises, in mole parts: 5-30 parts of diethanol amine, 5-75 parts of diethylenetriamine and 10-55 parts of o-phenylenediamine.
4. A process for preparing a curing agent for powder coating systems according to any of claims 1 to 3, comprising the steps of: 1) Adding polybasic acid into a reactor, adding a proper amount of ethanol as a solvent, and mixing and stirring; 2) Adding polyamine into the polybasic acid, and carrying out reflux reaction; 3) Distilling to remove the ethanol solvent, cooling the reaction mixture to room temperature, separating out crystals, carrying out vacuum filtration and drying to obtain the product.
5. The method of claim 4, wherein step 3) is carried out by adding catalyst in the formula amount, and gradually heating under inert gas atmosphere until no distillate is distilled out.
6. A process for preparing a curing agent for powder coating systems as claimed in claim 5, wherein the reaction temperature is not more than 225 ℃.
7. A process for preparing a curing agent for powder coating systems as claimed in claim 6, wherein the inert gas is selected from the group consisting of nitrogen and argon.
8. The method of claim 7, wherein in step 3), the reaction product is distilled off until the acid value of the reaction product is less than 80 mgKOH/g.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011398498.3A CN112625204A (en) | 2020-12-04 | 2020-12-04 | Curing agent for powder coating system and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011398498.3A CN112625204A (en) | 2020-12-04 | 2020-12-04 | Curing agent for powder coating system and preparation method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112625204A true CN112625204A (en) | 2021-04-09 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011398498.3A Withdrawn CN112625204A (en) | 2020-12-04 | 2020-12-04 | Curing agent for powder coating system and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112625204A (en) |
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2020
- 2020-12-04 CN CN202011398498.3A patent/CN112625204A/en not_active Withdrawn
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| PB01 | Publication | ||
| PB01 | Publication | ||
| WW01 | Invention patent application withdrawn after publication |
Application publication date: 20210409 |
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| WW01 | Invention patent application withdrawn after publication |