阅读说明：本技术 潜伏型胺系固化剂 (Latent amine curing agent ) 是由 张传明 黄家来 于 2021-09-09 设计创作，主要内容包括：本发明涉及一种潜伏型胺系固化剂,所述胺系固化剂经由曼尼希反应将取代或未取代的羟基芳香族化合物、取代或未取代的烷基结构引入到聚酰胺结构中,并以酮亚胺反应进行封端。(The present invention relates to a latent amine-based curing agent in which a substituted or unsubstituted hydroxyaromatic compound and a substituted or unsubstituted alkyl structure are introduced into a polyamide structure by a mannich reaction and blocked by a ketimine reaction.)

1. An amine-based curing agent, comprising:

1) a structural unit represented by the following general formula (I) and/or general formula (II); and

2) capping group represented by T:

in the general formula (I), L represents a residue of the polyamide after removal of two terminal amine groups; p represents a residue derived from a substituted or unsubstituted hydroxyaromatic compound; r₁The alkyl group is the same or different at each occurrence, and independently represents H or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms;

in the general formula (II), P and R₁Is as defined for formula (I); m is the same or different at each occurrence and independently represents a residue derived from an amine-based compound having two primary amines; k represents a residue derived from a dicarboxylic acid compound; y represents an integer of 1 to 5;

and T represents a blocking group having a ketimine structure.

2. The amine-based curing agent according to claim 1, wherein the substituted or unsubstituted hydroxyaromatic compound is selected from substituted or unsubstituted hydroxybenzenes or hydroxynaphthalenes.

3. The amine-based curing agent according to claim 1 or 2, wherein the substituted or unsubstituted hydroxyaromatic compound has a structure of the following general formula (III-1) or (III-2):

wherein x represents an integer of 0to 3;

R₂the same or different at each occurrence, independently represents a halogen atom, a saturated or unsaturated alkyl group, an aryl-containing group, or a heteroatom-containing group, and these groups may optionally have a substituent.

4. The amine-based curing agent according to any one of claims 1 to 3, wherein the end-capping group represented by T has a structure represented by the following general formula (IV):

wherein R is₃And R₄Each occurrence, which is the same or different, independently represents an alkyl group or an aromatic group, optionally, R₃And R₄May be bonded to form a ring.

5. The amine-based curing agent according to any one of claims 1 to 4, further comprising a compound having the following general formula (V):

P’-CHR₁-NH-L-T formula (V)

Wherein the content of the first and second substances,

L、R₁and T is as defined for formula (I);

p' represents a residue derived from the substituted or unsubstituted hydroxyaromatic compound.

6. The amine-based curing agent according to claim 5, wherein the compound of the general formula (V) comprises a compound having the following general formula (V-1):

wherein the content of the first and second substances,

x represents an integer of 0to 3;

R₂the same or different at each occurrence, independently represents a halogen atom, a saturated or unsaturated alkyl group, an aryl-containing group, or a heteroatom-containing group, and these groups may optionally have a substituent;

R₃and R₄Each occurrence, which is the same or different, independently represents an alkyl group or an aromatic group, optionally, R₃And R₄May be bonded to form a ring.

7. The amine-based curing agent according to any one of claims 1 to 6, wherein the polyamide is derived from polycondensation of a carboxylic acid compound and an amine-based compound;

the amine compound includes an amine compound having two primary amines selected from aliphatic, alicyclic, aromatic amine compounds, or a combination thereof;

the carboxylic acid compound comprises a dicarboxylic acid compound selected from aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, aromatic dicarboxylic acids, polyacids with two carboxyl end groups, or combinations thereof.

8. The amine-based curing agent according to any one of claims 1 to 7, wherein the amine value of the amine-based curing agent is 100 to 400mgKOH/g, preferably 150 to 300 mgKOH/g; the viscosity at room temperature is 10000 to 100000 mPas, preferably 15000 to 50000 mPas.

9. A curing agent composition comprising one or more amine-based curing agents according to any one of claims 1 to 8.

10. A curable composition comprising an epoxy resin and the curing agent composition of claim 9.

11. A cured film obtained by curing the curable composition according to claim 10.

Technical Field

The invention relates to the field of chemical products, in particular to an amine curing agent commonly used for epoxy resin, and more particularly relates to a latent amine curing agent.

Background

The epoxy resin is a thermosetting polymer material, can form a three-dimensional net-shaped three-dimensional structure by matching with a curing agent, has excellent physical and mechanical properties, insulating property and bonding property, and is widely applied to the engineering fields of coatings, adhesives, composite materials and the like. In an epoxy resin system, a curing agent is indispensable, and at present, most of the curing agents at normal temperature are amine and modified amine products, such as aliphatic amine, alicyclic amine, aromatic amine, polyamide and the like. Small-molecular amine has strong irritation to human bodies due to high volatility, and is limited in use, so that the small-molecular amine is not used as a normal-temperature curing agent basically. The common normal-temperature curing agent at present is mainly a modified amine product, and typical products comprise polyamide, phenolic aldehyde amine and the like.

The polyamide curing agent is a light yellow or brown yellow viscous liquid which is usually prepared by reacting vegetable oleic acid and dimer or trimer thereof with aliphatic polyamine at high temperature (above 180 ℃), has the relative molecular mass of 500-6000, is matched with epoxy resin for use, and has the advantages of long operable time, low volatility, almost no toxicity and little irritation to skin. The polyamide curing agent can be cured with epoxy resin at normal temperature to form a film, and the film has good corrosion resistance, flexibility and overlong recoatability. But the drying time is long, the low-temperature curing performance is poor, and normal construction cannot be carried out at the temperature lower than 15 ℃ under general conditions. In addition, it has high viscosity, low hardness and poor heat resistance.

The phenolic amine curing agent is usually a mixture of a phenolic substance, formaldehyde, a basic small molecule amine, and the like, which are produced by a mannich reaction. The phenolic hydroxyl is introduced into the molecules of the curing agent, so that the reaction activity of the curing agent is improved, the curing agent can be cured at normal temperature, low temperature (even about 0 ℃) and humid environment, and the limit of the temperature to the phenolic aldehyde amine is small when the curing agent is applied; a phenolic aldehyde skeleton structure is introduced into the molecule, so that the thermal deformation temperature of the cured epoxy resin is improved; the defects of high volatility, strong irritation and strong toxicity of the lower aliphatic amine are overcome. Meanwhile, the phenolic aldehyde amine curing agent has a wider resin mixing ratio, good adhesion and a longer pot life. And the oil resistance and chemical resistance of the product are better, but the biggest defects of the product are that the coating film is brittle and has poor toughness, and although the use of the common cardanol modified amine improves the brittleness and the toughness to a certain extent, the cardanol modified amine still has a gap with a polyamide curing agent.

In addition, the curing agents are all obvious curing agents, and as the technology develops, latent curing agents are gradually widely used due to various advantages. The latent curing agent can not react immediately after being matched with epoxy resin at room temperature, the composition can be stably placed for a long time at room temperature, and the curing agent can initiate curing reaction under the action of heat, light, moisture or pressure and is crosslinked with the epoxy resin to form a cured product. By utilizing the characteristic of the latent curing agent, the epoxy resin composition can be prepared into a single component, so that on-site material preparation is not needed during use, and the time, material waste and environmental pollution caused by material preparation times are reduced; the adverse effects on performance caused by metering errors and uneven mixing during double-component proportioning are avoided. The latent curing agent may be classified into various types such as a cationic curing type, a dissolution curing type, a thermal decomposition curing type, a photo-curing type, a moisture curing type, and the like, according to the initiation conditions of the latent curing agent.

The ketimine curing agent is modified amine with excellent performance, belongs to a moisture curing latent curing agent, is cured under the high humidity condition by matching with epoxy resin, and can be used in the industries of coatings, cathode electrophoretic paints and the like. The ketimine curing agent is a compound prepared by condensing and dehydrating ketone substances such as methyl ethyl ketone, methyl isobutyl ketone and the like with primary amine under specific conditions, has good stability at room temperature, only absorbs moisture on the surface of a moist base material or in a moist environment to decompose the moisture into amine and ketone, and the decomposed amine is subjected to curing reaction with epoxy resin.

Patent document cited in reference 1 discloses a method for directly synthesizing a ketimine curing agent using a small-molecular aliphatic amine, alicyclic amine, or aromatic amine. Methyl ethyl ketone, methyl isobutyl ketone or other ketones are reacted with base amines such as ethylenediamine, diethylenetriamine, isophoronediamine and the like. When the ketimine absorbs water to release low molecular amine substances such as ethylenediamine, diethylenetriamine, isophorone diamine and the like when being cured with epoxy resin, and the basic amine reacts with the epoxy resin to be crosslinked and cured. However, in practical application, the steam pressure of the released low-molecular amine is high, the irritation is large, the skin allergy of construction workers is easily caused, and the overflowed low-molecular amine also has certain toxicity.

The patent document cited in reference 2 discloses a method for preparing ketiminized polyamide, which comprises reacting polymerized fatty acid, vegetable oleic acid and vinylamine to form polyamide, and then synthesizing ketiminized polyamide curing agent with ketone substance and terminator. However, this method uses a quinone terminator, which is highly toxic, and the depolymerization rate and the drying rate of the paint film are slow, and it is difficult to form a hard paint film especially under low temperature conditions.

Patent document cited in reference 3 discloses that ketimine curing agents obtained by directly reacting modified amines such as low-molecular polyamides, cardanol-modified amines, and phenolaldehydamine with ketone-based substances are suitable for curing in a humid environment.

The patent document cited in reference 4 discloses a high-performance phenol-aldehyde amine curing agent for epoxy resin and a preparation method thereof, and the product is an epoxy resin curing agent with low viscosity suitable for low-temperature wet construction. The phenolic aldehyde amine is obtained by reacting small molecular polyamines such as phenol, cardanol, formaldehyde, ethylene polyamine and the like, and the defect of brittleness of common phenolic aldehyde amine is overcome.

Thus, despite the extensive research that has been conducted, there is still room in the art for improvement or enhancement of the performance of curing agents, particularly epoxy curing agents.

Cited documents:

cited document 1: US6573357B1

Cited document 2: CN101613471B

Cited document 3: CN108409601A

Cited document 4: CN101508764A

Disclosure of Invention

Problems to be solved by the invention

As described above, the curing performance of modified amines as curing agents has been studied in the prior art. In reference 3, ketimine is formed using a low molecular weight cardanol-modified amine or the like, which not only has latency but also improves epoxy film strength and impact strength, and further, there is no problem of bleeding of a small molecular amine. However, the hardness and corrosion resistance of the cured film are not mentioned, and in consideration of the condition of the molecular segment thereof, improvement of the toughness of the cured product cannot be said to be sufficient. The cited document 4 uses a small molecule amine in the synthesis, and still has a risk of release of amine molecules, and in addition, its toughness improvement is limited, and it is not a latent curing agent, nor does it mention the properties of hardness and corrosion resistance of the cured film.

Therefore, in view of some of the disadvantages of the amine-based curing agents of the prior art, it is an object of the present invention to provide a latent amine-based curing agent which combines a hydroxyaromatic structure with a (poly) amide structure by a Mannich (Mannich) reaction and is further blocked by a ketimine reaction, and as a result, not only allows the amine-based curing agent to have good latent and low-temperature curability, but also allows the cured epoxy film layer to have improved hardness, toughness and corrosion resistance.

Means for solving the problems

After long-term research by the present inventors, it was found that the above-mentioned technical problems can be solved by implementing the following technical means.

[1] The present invention first provides an amine-based curing agent, wherein the amine-based curing agent contains:

1) a structural unit represented by the following general formula (I) and/or general formula (II); and

2) capping group represented by T:

in the general formula (I), L represents a residue of the polyamide after removal of two terminal amine groups; p represents a residue derived from a substituted or unsubstituted hydroxyaromatic compound; r₁The alkyl group is the same or different at each occurrence, and independently represents H or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms;

in the general formula (II), P and R₁Is as defined for formula (I);

m is the same or different at each occurrence and independently represents a residue derived from an amine-based compound having two primary amines; y represents an integer of 1 to 5; k represents a residue derived from a dicarboxylic acid compound;

and T represents a blocking group having a ketimine structure.

[2] the amine-based curing agent according to [1], wherein the substituted or unsubstituted hydroxyaromatic compound is selected from substituted or unsubstituted hydroxybenzenes or hydroxynaphthalenes.

[3] The amine-based curing agent according to [1] or [2], wherein the substituted or unsubstituted hydroxyaromatic compound has a structure of the following general formula (III-1) or (III-2):

wherein x represents an integer of 0to 3;

R₂the same or different at each occurrence, independently represents a halogen atom, a saturated or unsaturated alkyl group, an aryl-containing group, or a heteroatom-containing group, and these groups may optionally have a substituent.

[4] The amine-based curing agent according to any one of [1] to [3], wherein the end-capping group represented by T has a structure represented by the following general formula (IV):

wherein R is₃And R₄Each occurrence, which is the same or different, independently represents an alkyl group or an aromatic group, optionally, R₃And R₄Can be linked into a ring。

[5] The amine-based curing agent according to any one of [1] to [4], wherein the amine-based curing agent further comprises a compound having a structure represented by the following general formula (V):

P’-CHR₁-NH-L-T formula (V)

Wherein the content of the first and second substances,

L、R₁and T is as defined for formula (I);

p' represents a residue derived from the substituted or unsubstituted hydroxyaromatic compound.

[6] The amine-based curing agent according to [5], wherein the compound of the general formula (V) includes a compound having a structure of the following general formula (V-1):

wherein the content of the first and second substances,

x represents an integer of 0to 3;

R₂the same or different at each occurrence, independently represents a halogen atom, a saturated or unsaturated alkyl group, an aryl-containing group, or a heteroatom-containing group, and these groups may optionally have a substituent;

R₃and R₄Each occurrence, which is the same or different, independently represents an alkyl group or an aromatic group, optionally, R₃And R₄May be bonded to form a ring.

[7] The amine-based curing agent according to any one of [1] to [6], wherein the polyamide is derived from polycondensation of a carboxylic acid compound and an amine-based compound;

the amine compound includes an amine compound having two primary amines selected from aliphatic, alicyclic, aromatic amine compounds, or a combination thereof;

the carboxylic acid compound comprises a dicarboxylic acid compound selected from aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, aromatic dicarboxylic acids, polyacids with two carboxyl end groups, or combinations thereof.

[8] The amine-based curing agent according to any one of [1] to [7], wherein the amine value of the amine-based curing agent is 100 to 400mgKOH/g, preferably 150 to 300 mgKOH/g; the viscosity at room temperature is 10000 to 100000 mPas, preferably 15000 to 50000 mPas.

[9] Further, the present invention also provides a curing agent composition, wherein the composition comprises one or more amine-based curing agents according to any one of the above [1] to [8].

[10] Further, the present invention also provides a curable composition, wherein the curable composition comprises an epoxy resin and the curing agent composition according to [9].

[11] In addition, the present invention provides a cured film, wherein the cured film is obtained by curing the curable composition according to [10].

ADVANTAGEOUS EFFECTS OF INVENTION

Based on the implementation of the technical scheme, the invention can obtain the following technical effects:

(1) the molecular chain based on polyamide is introduced, so that the molecular weight of the curing agent can be obviously improved, and meanwhile, the molecular weight of the curing agent can be further improved based on the chain extension effect provided by the Mannich reaction, so that the adhesion, flexibility and mechanical property of a cured product can be improved;

(2) through the Mannich reaction, phenolic hydroxyl groups and phenolic aldehyde skeleton structures can be introduced into a polyamide structure in a flexible mode in some specific embodiments, so that the reactivity of the curing agent is improved, and the rigidity of an epoxy cured film is improved; in addition, the modification of the Mannich reaction endows the curing agent with excellent low-temperature curing performance, and the curing agent can be directly used and constructed at low temperature;

(3) the polyamide is blocked through the ketimine reaction, so that the latency of the curing agent is further endowed, the field configuration process of a coating is avoided, and the use convenience is improved;

(4) the amine curing agent is non-toxic and non-irritant, and does not volatilize and overflow micromolecule amine in the product curing process, so that the phenomena of skin irritation and the like of operators can be avoided;

(5) through the integral molecular design, the curing agent disclosed by the invention has excellent flexibility, hardness and impact resistance and improved anti-corrosion performance after being mixed with epoxy resin for curing and film forming.

Drawings

FIG. 1: application example 2 film morphology comparison for impact testing

FIG. 2: application example 2 film coating 14-day continuous salt spray test form comparison

FIG. 3: dry film thickness test schematic

Detailed Description

The present invention will be described in detail below. The technical features described below are explained based on typical embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that:

in the present specification, the numerical range represented by "numerical value a to numerical value B" means a range including the end point numerical value A, B.

In the present specification, the numerical ranges indicated by "above" or "below" mean the numerical ranges including the numbers.

In the present specification, the meaning of "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

In the present specification, the term "more" means a numerical value of 2 or more.

As used herein, the term "optional" or "optional" is used to indicate that certain substances, components, performance steps, application conditions, and the like are used or not used.

In the present specification, "alkyl" and "saturated alkyl" have the same physical meaning; "unsaturated alkyl" means that one or more structures such as double or triple bonds are present in the molecular structure.

As used herein, "room temperature" means an indoor ambient temperature of "25 ℃.

In the present specification, the unit names used are all international standard unit names, and the "%" used means weight or mass% content, if not specifically stated.

As used herein, "structural unit" means one or more such structural fragments in a compound.

In the present specification, reference to "some particular/preferred embodiments," "other particular/preferred embodiments," "embodiments," and the like, means that a particular element (e.g., feature, structure, property, and/or characteristic) described in connection with the embodiment is included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various embodiments.

< first aspect >

A first aspect of the present invention provides an amine-based curing agent obtained by introducing a hydroxyaromatic and (substituted or unsubstituted) alkyl structure into a polyamide structure in a flexible manner by a mannich reaction, and further by a blocking reaction by ketiminization in the presence of a ketone compound.

Specifically, the amine curing agent is a compound containing the following structure or a mixture thereof:

1) a structural unit represented by the following general formula (I) and/or general formula (II); and

2) a blocking group represented by T, which is a blocking group formed by a ketimine structure, wherein the T group is obtained by subjecting-NH-H to a ketimine reaction when the-NH-in the structure of the following general formula (I) or general formula (II) is terminated with the-NH-H:

in the general formula (I), L represents a residue of the polyamide after removal of two terminal amine groups; p represents a residue derived from a substituted or unsubstituted hydroxyaromatic compound; r₁Each time phase of occurrenceIndependently represent H or substituted or unsubstituted alkyl with 1-6 carbon atoms;

in the general formula (II), P and R₁Is as defined for formula (I); m is the same or different at each occurrence and independently represents a residue derived from an amine-based compound having two primary amines; y represents an integer of 1 to 5, preferably an integer of 1 to 3, more preferably 1 or 2, and most preferably 1; k represents a residue derived from a dicarboxylic acid compound.

Preferably, the compound having a structural unit of the formula (I) or the formula (II) has a linear main chain structure, and one end or both ends have a blocking group T.

A compound having the structure of the general formula (I)

As for the compound having the structure of the above general formula (I), it can be considered as a result of the chain extension reaction of the polyamide polymer by the mannich reaction.

In some embodiments of the present invention, the amine-terminated polyamide can be obtained by performing a mannich reaction using a polyamide having two primary amine terminal groups, a substituted or unsubstituted hydroxyaromatic compound, and an aldehyde compound, and then performing a ketimine reaction on the primary amine groups (as terminal groups) in the reaction product with a ketone compound.

(Polyamide)

The polyamide of the present invention can be obtained by polycondensation of a carboxylic acid compound and an amine compound through amidation reaction.

The carboxylic acid compound is not particularly limited, and one or more of the polybasic acids commonly used in the synthesis of polyamides in the art may be used. For example, the polyacid may be one or more of an aliphatic, alicyclic, or aromatic polyacid having 4 to 60 carbon atoms. Preferably, the polybasic acid of the present invention is a dicarboxylic acid compound.

In some specific embodiments of the present invention, the polybasic acids include fatty acids having 4 to 15 carbon atoms such as adipic acid, azelaic acid, succinic acid, dodecanedioic acid, glutaric acid, suberic acid, maleic acid, pimelic acid, sebacic acid, undecanedioic acid, and the like; or aromatic dicarboxylic acids such as terephthalic acid, phthalic acid, and isophthalic acid.

In other embodiments of the invention, polymerized fatty acids are also suitable. Polymerized fatty acids, also referred to herein as "polyacids," are used herein. Typically, such "polyacids" may be present or used in the form of "dimer acids" or "trimer acids".

In the present invention, the fatty acid forming these "polyacids" may be unsaturated fatty acids having 10 or more carbon atoms, and preferably, may be unsaturated fatty acids having 12 to 30 carbon atoms. Typically, the polyacid-forming fatty acids suitable for use in the present invention are selected from a variety of oleic acids (linoleic acid, linolenic acid, rapeseed acid, soybean acid, palmitoleic acid, tall oil acid, etc.), linoleic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid, docosapentaenoic acid, or docosahexaenoic acid, among others.

Furthermore, in some embodiments of the invention, mixtures of polymerized fatty acids may also be used. Mixtures of polymerized fatty acids may be, for example, those obtained commercially from the polymerization of tall oil fatty acids. These polymerized fatty acids preferably have the following typical composition: based on the total weight of the polyacid, the polyacid comprises about 0-10 wt% of C18 monoacid (monomer), 60-95 wt%, sometimes up to about 98 wt% of C36 diacid (dimer), and about 1-35 wt% of C54 and higher polyacids (trimer). The relative proportions of monomers, dimers, and trimers in the polymerized fatty acid depend on the nature of the starting materials, the conditions of polymerization, and the degree of purification. The purer grades of polymerized fatty acids may be obtained by distillation and comprise at least 70 wt.%, preferably 80 wt.% and usually up to 95 wt.% or even 98 wt.% of dimerised fatty acid. Furthermore, these polymerized fatty acids or mixtures thereof may also be unhydrogenated or hydrogenated.

In some embodiments of the present invention, the fatty acids that form "polyacids" are derived from animal or vegetable fats and oils, preferably vegetable fats and oils.

Further, the amine compound used in the present invention is not particularly limited, and one or more of polyamine monomers commonly used in the synthesis of polyamides in the art may be used.

The polyamines of the present invention may be selected from diamines, triamines, or higher amines, where the number of amine units refers to the sum of primary, secondary, and tertiary amine groups. Also, these polyamines have two primary amine groups.

In some embodiments of the invention, one or more aliphatic, cycloaliphatic, or aromatic diamines may be used as the diamine.

The aliphatic diamine having two primary amine groups which can be used in the present invention may be a diamine having a linear structure or a branched structure. More preferably, those diamines having an even number of carbon atoms with primary amine groups at both ends may be used. In the present invention, the aliphatic diamine may contain 2 to 30 carbon atoms, preferably 2 to 26 carbon atoms, and further preferably 4 to 20 carbon atoms.

In addition, as the alicyclic diamine which can be used in the present invention, it may be a diamine having one or more aliphatic rings in the structure, and these aliphatic rings may have a common atom.

For the aromatic diamine that can be used in the present invention, it may be a diamine having one or more aromatic rings, preferably one or more benzene rings, in the structure.

More specifically, the diamine which may be exemplified in the present invention may be selected from ethylenediamine, 1, 3-diaminopropane, 1, 4-diaminobutane, 1, 3-diaminopentane, methylpentamethylenediamine, 1, 6-hexamethylenediamine, 1, 4-cyclohexanediamine, isophorone diamine, 4' -diamino-dicyclohexylmethane, norbornanediamine, trimethylhexamethylenediamine, 2-methylpentamethylenediamine, 1, 8-diaminooctane, neopentyldiamine, 1, 12-diaminododecane, diaminodipropylmethylamine, p-dodecylamine, and m-phenyldialkylamine.

In addition, the diamine of the present invention may comprise a polyoxyalkylene diamine (polyetherdiamine), such as polyoxyethylene diamine, polyoxypropylene diamine or bis- (diaminopropyl) -polytetrahydrofuran. Polyoxyalkylene diamines are commercially available under the trade name "Jeffamines" (Huntsman Co.).

In addition, triamines or higher amines, which may be selected from one or more aliphatic, alicyclic, or aromatic polyamines, may be used with the present invention. In some preferred embodiments, the polyamines may be selected from a variety of polyalkylene polyamines for these polyamines, more preferably such polyalkylene polyamines have two primary amine groups and one or more secondary amine groups. Typically, the polyalkylene polyamine may be selected from one or more of diethylenetriamine, dipropylenetriamine, triethylenetetramine, tetraethylenepentamine, and the like.

Further, the synthesis method of the polyamide of the present invention is not particularly limited, and the polyamide may be obtained by heating under polycondensation conditions common in the art and dehydrating and polycondensing the polyamide, and the polyamide may have a primary amine group at least at both ends. In addition, the molecular weight of the polyamide obtained may be 500 to 10000, preferably 1000 to 8000, and more preferably 1500 to 6000 in some specific embodiments of the present invention from the viewpoint of the cured coating film performance.

(substituted or unsubstituted hydroxyaromatic compound)

With respect to the substituted or unsubstituted hydroxyaromatic compound described in formula (I), in some particular embodiments of the present invention, it may be selected from substituted or unsubstituted hydroxybenzenes, substituted or unsubstituted hydroxynaphthalenes, or combinations thereof.

In some preferred embodiments of the present invention, the substituted or unsubstituted hydroxyaromatic compound has the following general formula (III-1) or (III-2):

wherein x represents an integer of 0to 3, preferably 0, 1 or 2, and more preferably 1 or 2.

For R₂And may be the same or different at each occurrence. In some specific embodiments, R₂May be selected from halogen atoms, preferably, may be chlorine or fluorine atoms; in other specific embodiments, R₂May be selected from saturated or unsaturated alkyl groups, aryl-containing groups or heteroatom-containing groups, and these groups may optionally have substituents. The saturated or unsaturated alkyl group may be selected from saturated or unsaturated alkyl groups having 1 to 50 carbon atoms, preferably 5 to 45 carbon atoms, and more preferably 10 to 35 carbon atoms. Further, as for the unsaturated alkyl group, it may be one having one or more unsaturated bonds in its alkyl structure, especially a double bond or triple bond structure. With respect to the above-mentioned saturated or unsaturated alkyl groups, in some specific embodiments, there may be further provided a substituent, for example, wherein one or more hydrogen atoms may be substituted with a halogen atom, particularly a fluorine atom. The aryl-containing group may be a phenyl group or a substituted phenyl group, and in some embodiments, such a substituent may be one or more halogen atoms, or a saturated or unsaturated alkyl group having 1 to 50 carbon atoms which is substituted or unsubstituted with a halogen atom. The hetero atom-containing group may be a group having O, S or N element in the above-mentioned saturated or unsaturated alkyl group or aryl group-containing group, and specifically, may be a group having an ether group, a thioether group, a sulfone group, a tertiary amine group or the like.

In addition, in the structure of the above general formula (III-1) or (III-2), R is preferably₂Is not adjacent to the hydroxyl group of the hydroxyaromatic compound.

(aldehyde compound)

For the aldehyde compound, one or more compounds having R may be used₁Aldehydes of the structure-CHO, in which R is₁The alkyl group may be the same or different at each occurrence, and may represent H or an alkyl group having 1 to 6 carbon atoms, such as methyl, ethyl, isopropyl, butyl, or the like. In some preferred embodiments of the invention, R₁Can be H,Methyl or ethyl, further preferably, R₁Is H or methyl, more preferably, R₁Is H.

(end capping group T)

T in the structure of the general formula (I) represents a blocking group having a ketimine structure. The ketimine structure is a primary amino and ketone compound (R)₃-(C＝O)-R₄) Structure obtained by ketimine reaction.

In some specific embodiments of the invention, T has the structure of formula (IV):

wherein, for R₃And R₄Derived from ketone compounds (R)₃-(C＝O)-R₄) Each occurrence of which is the same or different and independently represents an alkyl group or an aromatic group. The alkyl group may be a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms in some preferred embodiments, and more preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group or the like. The aromatic group is a group having 6 to 30 carbon atoms and containing a phenyl group, a naphthyl group, or a biphenyl group, and optionally, these groups may have a substituent on the aromatic ring.

In addition, in some specific embodiments, R₃And R₄It may also be bonded to form a ring.

A compound having the structure of the general formula (II)

The compound having the structure of the general formula (II) can be considered to be a result of a chain extension reaction of a polyamine monomer by a mannich reaction to form a polyamide polymer.

In some embodiments of the present invention, the compound can be obtained by performing a mannich reaction using an amine compound having two primary amino groups, a substituted or unsubstituted hydroxyaromatic compound, and an aldehyde compound to obtain a product having one or two terminal primary amino groups, and then continuing the reaction of the product with a dicarboxylic acid compound.

The substituted or unsubstituted hydroxyaromatic compound, the aldehyde compound and the blocking group T may be selected from the same compounds as in the general formula (I).

The amine compound having two primary amines may be selected from aliphatic, alicyclic, aromatic amine compounds or a combination thereof, and may be selected from one or more of diamine, triamine or higher amine compounds having two primary amine groups as mentioned in the above general formula (I). Therefore, M in the structure of the general formula (II) above represents a residue derived from these amine-based compounds having two primary amines.

As the dicarboxylic acid compound, it may be selected from aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, aromatic dicarboxylic acids, polyacids having two carboxyl end groups, or combinations thereof, and for example, it may be selected from one or more of the dicarboxylic acids mentioned in the general formula (I). Therefore, K in the structure of the above general formula (II) represents a residue derived from these dicarboxylic acid compounds.

A compound having a structure of formula (V)

In some other preferred embodiments of the present invention, the amine-based curing agent of the present invention comprises a compound having the following general formula (V) in addition to the compound having the above general formula (I) and/or general formula (II) and the structure of the end capping group T:

P’-CHR₁-NH-L-T formula (V)

Wherein, L, R₁And T is as defined for formula (I).

P' represents a residue derived from the substituted or unsubstituted hydroxyaromatic compound, which may serve as a terminal group.

The compound having the structure of the general formula (V) can be obtained by subjecting a substituted or unsubstituted hydroxyaromatic compound to a mannich reaction with an aldehyde compound and a polyamide (in this case, one end of the polyamide is capped with the structure P' by the mannich reaction), and further subjecting the other end of the polyamide to a ketimine reaction with a ketone compound.

Alternatively, a substituted or unsubstituted hydroxyaromatic compound, an aldehyde compound, and an amine compound having two primary amino groups may be subjected to a mannich reaction to obtain an amine compound mixture having a portion of one end portion capped with the structure P ', and then these mixtures may be subjected to a condensation reaction with a dicarboxylic acid compound to obtain a polyamide having one end capped with the structure P' and the other end portion having a primary amino group, and the polyamide may be subjected to a ketimine reaction with a ketone compound to finally obtain the compound of the general formula (V).

The substituted or unsubstituted hydroxyaromatic compound, the aldehyde compound, the polyamide, the amine compound having two primary amino groups, and the ketone compound may be the same as those of the general formula (I).

In some preferred embodiments of the present invention, the compound of formula (V) comprises the structure of formula (V-1) below, wherein R₁、R₂、R₃、R₄X and L are as defined above:

further, the above general formula (V-1) is preferably selected from the following structures:

further, the above-mentioned general formula (V-1-1) is preferably selected from the following structures:

in addition, in some embodiments of the present invention, the amine-based curing agent of the present invention comprises at least the compound of the above general formula (V-1-1 a).

The amine curing agent mainly comprises the compound of the structural unit shown in the general formula (I) or the general formula (II) and the compound with the structure shown in the general formula (V) which is optionally included, and the main chain of the compound with the structure has a linear (non-crosslinking) structure. In some specific embodiments of the present invention, the content of the component having a linear structure in the amine-based curing agent is 80% by mass or more, preferably 85% by mass or more, more preferably 90% by mass or more, and still more preferably 95% by mass or more, based on the total weight of the amine-based curing agent.

< second aspect >

In a second aspect of the present invention, there is provided a method for producing the amine-based curing agent of the first aspect. The amine-based curing agent of the first aspect of the present invention is not limited to a specific production method, but can be produced by the following first method and second method of the present invention, preferably, from the viewpoints of ease of synthesis, yield, and the like.

In some specific embodiments, the method for preparing the amine-based curing agent (first method) of the present invention comprises:

i) a polyamide synthesis step;

ii) a modification step of the polyamide via a mannich reaction;

iii) a step of ketiminization.

(Synthesis step of Polyamide)

The synthesis step of the polyamide of the present invention is not particularly limited, and may be carried out by an amidation condensation reaction which is conventional in the art.

In some specific embodiments, the acid groups and amine groups of the starting materials are present in approximately stoichiometric amounts, and, to obtain a terminal primary amine group structure, the polyamine is typically in stoichiometric excess. That is, it is preferable that residual amine groups are present after polycondensation. To achieve this, a polyamine compound having an excess of not more than 10 equivalent% of the corresponding functional group in the raw materials is used. In order to control the viscosity of the polyamide composition, it may be controlled by adding a small amount of monofunctional amine compound or fatty acid. The reaction temperature is not particularly limited, and the condensation reaction may be carried out at 150 to 270 ℃.

(Mannich reaction modification step)

In the present invention, the polyamide obtained by the above synthesis is subjected to a mannich reaction in combination with the above-mentioned substituted or unsubstituted hydroxyaromatic compound and the above-mentioned aldehyde compound to react with the primary amine at both terminal groups of the polyamide or to terminate one terminal group of the polyamide.

The substituted or unsubstituted hydroxyaromatic compound may be selected from the group consisting of phenols, naphthols, and preferably, these hydroxyl-containing aromatic compounds have one or more of R as described above₂A substituent group. In some embodiments, it is preferred to use phenols or naphthols substituted with long chain (straight chain alkyl groups having 10 to 35 carbon atoms, which may be saturated or unsaturated alkyl groups).

The aldehyde compound is not particularly limited, and one or more kinds of aldehyde substances which can be subjected to phenol condensation in the art may be selected, and specifically, formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde and the like may be listed. Preferably, the aldehyde compound of the present invention may be formaldehyde or acetaldehyde, more preferably formaldehyde. These aldehydes may be used in the form of monomers or in the form of polyaldehydes.

In some specific Mannich reaction embodiments of the present invention, the polyamide and the substituted or unsubstituted hydroxyaromatic compound may be combined first, typically with heating and optionally in the presence of an inert solvent. Further, an aldehyde compound is added to the mixture obtained in the above step. In some preferred embodiments, the aldehyde compound may be added dropwise.

And performing Mannich reaction in the process of adding formaldehyde and releasing heat, wherein the temperature of the mixed system is increased, and after the addition of the aldehyde substances is finished, the temperature of the system is kept at 70-150 ℃, preferably 75-140 ℃, and the heat preservation reaction is continuously performed for 2-6 hours. Too high a reaction temperature or too long a reaction time may result in the generation of undesirable nonlinear structures.

Other auxiliary means for the Mannich reaction are not particularly limited, and examples thereof include stirring, dehydration under reduced pressure, and dehydration with water in a solvent.

As a result of the mannich reaction, a structure of the formula (I) described in the first aspect, which may be present in the form of a repeating unit and at least one terminal portion of which is a primary amine group, may be obtained.

(step of ketiminization)

And cooling the Mannich reaction product obtained in the previous step to perform ketone imidization after adding a ketone compound.

In some specific embodiments, the temperature of the system after the Mannich reaction is reduced to 50-70 ℃, and then the ketone compound is added. As the ketone compound, there may be mentioned a ketone compound formed of an alkyl group or an aromatic group, and a ketone compound formed of an alkyl group is preferable.

The alkyl group may be a linear, branched or cyclic alkyl group having 1 to 30 carbon atoms in some preferred embodiments, and more preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group or the like. The aromatic group is a group having 6 to 30 carbon atoms and containing a phenyl group, a naphthyl group, or a biphenyl group, and optionally, these groups may have a substituent on the aromatic ring.

Specific examples of the ketone compound of the present invention include acetone, methyl ethyl ketone, methyl propyl ketone, methyl isopropyl ketone, methyl butyl ketone, and methyl isobutyl ketone.

In the present invention, one kind of ketone compound to be subjected to ketiminization reaction may be used, or two or more kinds of mixed ketones may be used.

In addition, as for the amount of the ketone compound to be used, generally, the ketone compound is used in excess, that is, the carbonyl group in the reaction system: the primary amino group is more than 1:1 and less than 1:3, and the excessive ketone compound can be used as a solvent, and can be beneficial to removing the generated water in the system by means of distillation, water separation and the like.

The system is heated to above 100 deg.C (depending on the ketone species) in the presence of the ketone species, and generally below 140 deg.C, preferably below 130 deg.C. The reaction time of the ketimine reaction is not particularly limited, and may be 1 to 4 hours. In some specific embodiments, the reaction is terminated until the water separator no longer produces water. Further, the final product is obtained by removing the residual ketone compound in the reaction system through continuous distillation.

In addition to the synthetic methods described above, the following synthetic methods (second method) may also be employed in some specific embodiments of the present invention:

i') mixing an aromatic compound containing hydroxyl, an aldehyde compound and a small molecular polyamine to carry out Mannich reaction;

ii') adding a dibasic acid to the Mannich-reacted system to carry out amidation (polymerization);

iii') a step of ketiminization.

In the reaction of step i', since a mannich reaction can be performed at a low temperature (e.g., 70 to 150 ℃), a part of the small-molecule polyamine undergoes a mannich reaction with the aldehyde compound and the substituted or unsubstituted hydroxyaromatic compound. The reaction results in the production of chain-extended polyamines, i.e.structural polyamines of the general formula (II-1):

wherein y is an integer of 1 to 5, preferably an integer of 1 to 3, more preferably 1 or 2, and still more preferably 1.

Further, in the step ii', the temperature of the system is increased continuously, for example, to 170-260 ℃ for amidation reaction. That is, the chain extension reaction gives a polycondensation reaction of the polyamine and the dicarboxylic acid compound to form the (poly) amide. Thus, in this process, the small-molecule polyamine, the aldehyde compound, and the substituted or unsubstituted hydroxyaromatic compound participating in the mannich reaction are introduced into the (poly) amide structure together to form the compound having the structure of the general formula (II).

For step iii', it can be operated in the same way as step iii of the first method described previously.

The amine-based curing agent of the present invention is obtained by the first method or the second method. The amine curing agent of the present invention may have an amine value of 100 to 400mgKOH/g, preferably 150 to 300mgKOH/g, more preferably 170 to 270mgKOH/g, and still more preferably 180 to 250 mgKOH/g. Too low an amine number may affect the curing effect, and too high an amine number may adversely affect or risk the flexibility, hardness, etc. of the final coating or film. In the present invention, the "amine value" can be determined by a titration method which is generally used in the art.

The viscosity of the amine-based curing agent of the present invention may be 10000 to 100000 mPas, preferably 15000 to 50000 mPas, more preferably 18000 to 45000 mPas, and still more preferably 20000 to 40000 mPas. In the present invention, the viscosity can be measured by a Brookfield DV-S viscometer at 25 ℃.

In addition, the amine-based curing agent obtained by the above method is mainly a compound having a linear structure, since the reaction conditions in the mannich reaction are non-strongly basic conditions or a strongly basic catalyst is not present. And optionally, in order to make the linear structure content of the final product increased to facilitate on-site application, the component having a crosslinked structure may be removed by a dissolution-filtration method. The method of dissolution-filtration is not particularly limited, and the treatment may be carried out in accordance with an operation method generally used in the art.

< third aspect >

In a third aspect of the present invention, there is provided a curing agent composition comprising the amine-based curing agent of the present invention.

In addition to the above-mentioned amine-based curing agents of the present invention, other types of epoxy curing agents known in the art may be used in the curing agent composition for any purpose, including but not limited to: phenolic substances, phenolic resins, polyisocyanates, polyamides, alcohol compounds (including polymer alcohols such as small molecular alcohol compounds and polyether polyols), amine compounds (monoamines or polyamines) and carboxyl-containing compounds.

In some preferred embodiments of the present invention, the curing agent composition may be a mixture of the amine-based curing agent of the present invention and one or more of a phenolic resin, a polyamide.

In addition to the various curing agents disclosed above, the curing agent composition of the present invention may also include an accelerator for epoxy curing. The curing accelerator is selected from any one of imidazole compounds, tertiary amine compounds, dicyandiamide, quaternary ammonium salt, organophosphorus compounds, pyridine compounds and DBU; preferably, the imidazole compound is selected from any one or a combination of at least two of 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-phenylimidazole, 2-heptadecylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole and trimellitic acid 1-cyanoethyl-2-undecylimidazolium salt; preferably, the tertiary amine compound is selected from any one or a combination of at least two of triethanolamine, tetramethylguanidine, triethylenediamine, benzyldimethylamine or N, N-dimethylpiperazine; preferably, the organophosphorus compound is triphenylphosphine and derivatives thereof.

In some preferred embodiments of the present invention, the curing agent composition contains at least 50% by mass or more of the amine-based curing agent of the present invention, preferably 60% by mass or more, and more preferably 70% by mass or more or 80% by mass or more.

< fourth aspect >

In a fourth aspect of the present invention, there is provided a curable composition comprising the above-described curing agent composition.

In some specific embodiments, the curable composition of the present invention includes an epoxy component and the curing agent composition.

The epoxy component is not particularly limited and may be an epoxy resin commonly used in the art, and in particular, an epoxy resin that can be used to form a coating or film.

In general, such epoxy component may include glycidyl ether type epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, alicyclic type epoxy resin, silicone modified epoxy resin, and the like.

The glycidyl ether epoxy resin can be bisphenol A epoxy resin, hydrogenated bisphenol A epoxy resin, o-cresol formaldehyde epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, tetramethyl biphenyl epoxy resin, biphenyl phenol epoxy resin and dicyclopentadiene diphenol epoxy resin.

The glycidyl ester epoxy resin can be diglycidyl phthalate, diglycidyl hexahydrophthalate, diglycidyl terephthalate, diglycidyl isophthalate, diglycidyl tetrahydrophthalate, diglycidyl methyltetrahydrophthalate, diglycidyl endomethyltetrahydrophthalate and diglycidyl adipate.

The glycidyl amine epoxy resin can be triglycidyl isocyanurate, triglycidyl para-aminophenol, tetraglycidyl diaminodiphenylmethane, diisopropylidenylidene tetraglycidyl amine, tetramethylisopropylidenylidene tetraglycidyl amine, N, N, N ', N ' -tetracyclooxypropyl-4, 4-diaminodiphenylmethane and 4,4' -diaminodiphenyl ether tetraglycidyl amine.

The alicyclic epoxy resin may be 3, 4-epoxycyclohexylmethyl 3, 4-epoxycyclohexyl formate, bis ((3, 4-epoxycyclohexyl) methyl) adipate, 4, 5-epoxycyclohexane-1, 2-dicarboxylic acid diglycidyl ester, 4-vinyl-1-cyclohexene diepoxide, dicyclopentadiene diepoxide, 1, 4-cyclohexanedimethanol bis (3, 4-epoxycyclohexanecarboxylic acid) ester.

The organosilicon modified epoxy resin comprises a modified epoxy resin with an organosilicon structure introduced into an epoxy molecule to increase toughness.

In some preferred embodiments of the present invention, the epoxy resin is selected from one or more of bisphenol a type epoxy resin, o-cresol novolac type epoxy resin, tetramethyl biphenyl type epoxy resin, dicyclopentadiene diphenol type epoxy resin, and triglycidyl isocyanurate. More typically, e.g., E51 epoxy or the like may be used.

With respect to the other components in the above composition, there is no particular limitation, and optionally, any one or a combination of at least two of a diluent, flame retardancy, solid filler, antifoaming agent, antistatic agent, leveling agent, coupling agent, aging inhibitor, anti-settling agent, wetting dispersant, or toughening agent may be included.

For diluents, reactive or non-reactive diluents can be used to adjust the viscosity of the system, such diluents include, but are not limited to: c₁₂～C₁₄One or more of alkyl glycidyl ether, butyl glycidyl ether, benzyl glycidyl ether, 1, 4-butanediol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, 1, 2-cyclohexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, benzyl alcohol, phenethyl alcohol, nonylphenol, propylene carbonate, trimethylolpropane triacrylate, diisopropanol methyl ether, toluene, xylene, and the like.

As the flame retardant, for example, an aromatic group-containing phosphorus flame retardant, a fluorine flame retardant, and the like can be used.

For the solid filler, it may be selected from any one or a combination of at least two of white carbon black, titanium dioxide, aluminum hydroxide, carbon black, zinc stearate, talc, calcium carbonate, barium sulfate, montmorillonite, diatomaceous earth, kaolin, gypsum, mica, magnesium hydroxide, or conductive materials (carbon nanotubes, graphene, conductive metal particles).

Further, the curable composition of the present invention can be applied to adhesives, coating films. In some embodiments, the curable composition of the present invention can be adjusted to a liquid coatable state at a suitable temperature, and coated on a substrate by roll coating or other spreading method, and further cured by applying a certain temperature and humidity to obtain a cured coating or film layer.

Examples

Hereinafter, the technical solution of the present invention will be described by specific examples.

(raw materials)

Dimer acid (dimer of soybean oleic acid), oleic acid were purchased from tomayu-kuan (thaxing) limited;

diethylenetriamine, triethylene tetramine, tetraethylenepentamine were purchased from Tosoh corporation;

mixed vinylamine was purchased from noreon chemicals (ningbo) ltd;

cardanol was purchased from Nanjing Jinhaiwei, Inc.;

phenol, formaldehyde solution, methyl isobutyl ketone and methyl ethyl ketone were purchased from shanghai Lingfeng Chemicals, ltd.

Example 1

Raw materials: 313g of dimer acid, 47g of soybean oleic acid, 203g of triethylene tetramine, 73g of phenol, 92g of formaldehyde solution (37%) and 273g of methyl ethyl ketone.

The implementation steps are as follows:

sequentially adding phenol and triethylene tetramine into a four-port reaction kettle, stirring and mixing uniformly, slowly dropwise adding a formaldehyde solution, and controlling the temperature to be not more than 80 ℃. After the addition, the temperature was raised to 80 ℃ and the temperature was maintained for 3 hours, and the pressure was reduced to 90Torr for dehydration.

Then, dimer acid and oleic acid are added at one time, the temperature is raised to 250 ℃, and the temperature is kept for 3 hours. To obtain the alkylphenol modified polyamide curing agent.

Cooling the curing agent to 60 ℃, adding methyl ethyl ketone, heating to 100 ℃ for reflux reaction, continuously separating water generated by the reaction through a water separator on the reactor and discharging the water until no water flows out, and discharging the ketone and the water in the reactor to obtain the final curing agent product.

According to the structure detection, the curing agent is a mixture of compounds with the following structural units:

wherein, in the above structural formula, the sites where these structures are keyed into the compound are represented; r₅Meaning that the two terminal carboxyl groups of the dimer acid are removedA residue moiety; r₆The residue portion of oleic acid minus the carboxyl group is shown.

Further, the amine value of the amine-based curing agent product was measured by titration method at 228mgKOH/g and the viscosity was measured by viscometer at 25100 mPas (25 ℃).

Example 2

Raw materials: 380g of dimer acid, 215g of triethylene tetramine, 202g of cardanol, 69g of formaldehyde solution (37%) and 134g of methyl isobutyl ketone.

The implementation steps are as follows:

sequentially adding dimer acid and triethylene tetramine into a four-port reaction kettle, uniformly stirring, filling nitrogen, heating to 250 ℃, and carrying out heat preservation reaction for 3 hours.

And after the reaction is finished, cooling to 60 ℃, adding cardanol, uniformly mixing, slowly dropwise adding a formaldehyde solution, heating to 100 ℃, keeping the temperature for 3 hours, and then decompressing to 90Torr for dehydration until no water flows out to obtain the alkylphenol modified phenolic aldehyde amine curing agent.

Cooling the curing agent to 60 ℃, adding methyl isobutyl ketone, heating to 100 ℃ for reflux reaction, continuously separating water generated by the reaction through a water separator on the reactor and discharging the water until no water flows out, and discharging the ketone and the water in the reactor to obtain the final curing agent product.

According to the structure detection, the curing agent is a mixture of compounds with the following structural units:

wherein, in the above structural formula, the sites where these structures are keyed into the compound are represented;means that the residue part of polyamide formed from the dimer acid and triethylene tetramine is removed from the amine groups at both ends; r₇Related to the cardanol starting material, R₇Each occurrence represents one of the following structural units:

further, the amine value of the amine-based curing agent product was measured by a titration method at 192mgKOH/g, and the viscosity was measured by a viscometer at 31510 mPas (25 ℃ C.).

Example 3

Raw materials: 524g of dimer acid, 141g of diethylenetriamine, 47g of tetraethylenepentamine, 49g of phenol, 19g of paraformaldehyde and 220g of cyclohexanone.

The implementation steps are as follows:

sequentially adding phenol, diethylenetriamine and tetraethylenepentamine into a four-port reaction kettle, stirring and mixing uniformly, slowly adding paraformaldehyde in batches, and controlling the temperature to be not more than 80 ℃. After the addition, the temperature was raised to 80 ℃ and the temperature was maintained for 3 hours, and the pressure was reduced to 90Torr for dehydration. And then adding dimer acid at one time, heating to 250 ℃, and preserving the temperature for hours to obtain the alkylphenol modified polyamide curing agent.

Cooling the curing agent to 60 ℃, adding cyclohexanone, heating to 100 ℃ for reflux reaction, continuously separating water generated by the reaction through a water separator on the reactor and discharging the water until no water flows out, and discharging ketone and water in the reactor to obtain a final curing agent product.

According to the structure detection, the curing agent is a mixture of compounds with the following structural units:

wherein, in the above structural formula, the sites where these structures are keyed into the compound are represented; r₅The residue part of the dimer acid with two terminal carboxyl groups removed is shown; m represents 0 or 1.

Further, the amine value of the amine-based curing agent product was measured by a titration method at 201mgKOH/g, and the viscosity was measured by a viscometer at 39480 mPas (25 ℃ C.).

Example 4

Raw materials: 41g of oleic acid, 499g of dimer acid, 201g of triethylene tetramine, 70g of mixed vinylamine, 45g of phenol, 34g of paraformaldehyde and 110g of acetone.

The implementation steps are as follows:

sequentially adding oleic acid, dimer acid and triethylene tetramine, mixing vinylamine in a four-port reaction kettle, uniformly stirring, filling nitrogen, heating to 250 ℃, and carrying out heat preservation reaction for 3 hours.

After the reaction is finished, cooling to 60 ℃, adding phenol, uniformly mixing, slowly adding paraformaldehyde in batches, heating to 100 ℃, keeping the temperature for 3 hours, then decompressing to 90Torr for dehydration until no water flows out, and obtaining the alkylphenol modified phenolic aldehyde amine curing agent.

Cooling the curing agent to 60 ℃, adding acetone, heating to 100 ℃ for reflux reaction, continuously separating water generated by the reaction through a water separator on the reactor and discharging the water until no water flows out, and discharging the ketone and the water in the reactor to obtain the final curing agent product.

According to the structure detection, the curing agent is a mixture of compounds with the following structural units:

wherein, in the above structural formula, the sites where these structures are keyed into the compound are represented;means that the residue part of polyamide formed by the dimer acid, triethylene tetramine and mixed vinylamine is removed two end amino groups; - - -represents the residue moiety derived from triethylenetetramine or mixed vinylamines, excluding the terminal amine groups.

Further, the amine value of the amine-based curing agent product was determined by titration to 247mgKOH/g, and the viscosity was determined by viscometer to 33600 mPas (25 ℃ C.).

Application example 1

100 parts of the amine curing agent prepared in example 1 and 60 parts of butyl glycidyl ether are fully mixed for 2 hours at 60 ℃, and 80 parts of epoxy resin E51 are added after the system temperature is reduced to room temperature and are fully and uniformly mixed.

The storage stability of the amine curing agent is evaluated mainly according to the change of the viscosity of a formula system, the storage stability is poor due to the obvious increase of the viscosity of the system, and the storage stability is good due to the unobvious increase of the viscosity of the system. And (3) placing the prepared sample in a vacuum drying oven with the vacuum degree of 0.1MPa for drying and defoaming for 30 min. Referring to GB/T7123.2-2002, the change in tack and its workability of the cured system when stored at room temperature (25. + -. 2 ℃) for different periods of time is recorded and the results are shown in Table 1. The viscosity of the system did not increase significantly over 100 days, indicating that the curable composition containing the curing agent of example 1 and the epoxy resin had better storage stability.

TABLE 1 measurement of viscosity of the system

Time/day	0	15	30	45	60	75	90	100
									viscosity/mPas	12870	13590	13790	15990	16290	17090	17190	17490

Application example 2

The amine-based curing agent product obtained in example 1 was selected for testing the application effect of the epoxy resin-containing paint, and compared with commercially available ketimine curing agent (product manufacturer and brand: Sunmide 3155) under the same experimental conditions for paint performance, mainly for performance comparison as shown in Table 2 below.

TABLE 2 comparison of coating Properties

Test items	Commercial product	Products of the invention
			Dry film thickness	26um	24um
Hardness of pencil	3H	4H
			Flexibility	1mm	1mm
Impact strength	80cm	100cm
			Impact testing of film morphology	FIG. 1a	FIG. 1b
14 days continuous salt spray test	FIG. 2a	FIG. 2b

Preparation of test panels:

three test panels were prepared for each item to be tested. The former uses sand washing steel plate (SA 2)¹/₂) And dimensions of about 150mm x 75mm x 1.5 mm. According to the preset specification, the coating is ensured to be smooth and has no defects (such as pinholes and missing coating). The constructed panel was allowed to stand for two weeks at room temperature for drying/curing.

Dry film thickness test method:

after the coating film has completely dried, the dry film thickness can be determined according to the national standard GB1764-89 (79). Five points were taken on the test surface of the test panel to measure the dry film thickness of the coating using a dry film thickness meter (see FIG. 3). The film thickness data around the scribe line was recorded and averaged. In fig. 3, "x" indicates five scribe lines.

The pencil hardness test method comprises the following steps:

after the film has completely dried, the hardness of the dry film can be measured according to the standard ASTM D3363-2005 "Standard test methods for measuring film hardness by Pencil test method". The coated plate was placed on a firm horizontal surface with the pencil held firmly against the coating at a 45 ° angle (pointing opposite the operator) and pushed 6.5-mm (1/4-in.) away from the operator at a time. This step is performed by first using the hardest pencil and then gradually decreasing the hardness on the hardness scale until the pencil does not cut or gouge into the coating, i.e. the pencil hardness.

Flexibility test method:

paint films are prepared and dried on tin plates according to the regulations of the national standard GB 1727-92 general paint film preparation method, and then experiments are carried out according to the specified constant temperature and humidity conditions and time. The test is carried out according to the provisions of national standard GB 1731-93 paint film flexibility determination method, during the test, a test plate paint film is upwards pressed on a shaft rod with a specified diameter by using two hands, the test plate is bent around the shaft rod by using the force of two thumb fingers, the two thumb fingers are symmetrical to the central line of the shaft rod after the test plate is bent, and the bending action is completed within 2-3 s. After bending, the paint film is observed with a 4-fold magnifying glass. And (4) checking whether the paint film has the phenomena of reticulate cracks, peeling and other damage phenomena, and if the phenomena of cracks, peeling and the like exist, the paint film is unqualified.

Test method for impact strength:

the impact strength test is carried out according to the regulations of the national standard GB 1732-79 'coating impact resistance test method'. And placing the sample on a base of an impact instrument, enabling a weight to fall from a preset height, checking whether a coating film in a groove impacted by the sample is cracked or whether the coating film is separated from a bottom plate, changing the height, and obtaining the maximum height of the coating layer without cracking or separating. The edge distance of each impact point is not less than 15mm, the impact part is not less than 15mm from the edge of the sample, and two points are measured on each sample. The impact strength of the coating film is generally expressed in terms of the maximum height that does not cause the coating film to be damaged, and the height is expressed in centimeters. The higher the height, the greater the potential energy converted to kinetic energy, and the stronger the impact force generated, indicating the higher the impact strength of the sample.

The method for testing the corrosion resistance of the coating film comprises the following steps:

the invention adopts a 14-day continuous neutral salt spray test method to test the corrosion resistance of a coating, and the method comprises the following specific steps:

(1) the test panels (two panels for each) were placed in a salt spray cabinet and marked. The plate is placed in the salt spray box at a position which avoids the salt spray nozzle, the surface to be measured faces upwards and forms an angle of 15-25 degrees with the plumb line, and the scribing part is ensured to be close to the plate bracket. The test panels are spaced apart a suitable distance so that the salt spray can fall on the test surface uniformly and without obstruction. Care was taken to ensure that the saline solution on the test plate did not drip onto the other test plates.

(2) The salt spray tank is set and used with reference to standard ISO 7253: 35. + -.2 ℃ 50. + -.5 g/l aqueous sodium chloride solution, pH 6.5-7.2, spray solution collection rate: 1-2.5ml/h pr 80cm²(refer to standard ISO 7253 for more information such as operation, maintenance, calibration, interior cabin design, etc.). Note that: the collected salt solution cannot be recycled.

(3) The test panel is inspected periodically taking care not to damage the test surface of the test panel. The viewing process is rapid to prevent the test panels from drying out. The observed phenomena were recorded for example: tarnishing, blistering, etc. Reference is made in particular to section 2-6 of the criteria ISO 4628.

(4) After the test is finished, the test plate is taken out from the salt spray box and washed clean by warm water, and the degradation conditions of the paint film of the test surface, such as blistering, corrosion and corrosion spread at a scribing part, are checked after the test plate is dried, and the specific method refers to 2-6 parts of the standard ISO 4628.

Referring to FIGS. 1-3, FIG. 1 is a photograph showing the impact strength of a sample film after impact strength test, wherein (a) is a photograph showing the impact strength test of a commercially available ketimine curing agent (Sunmide 3155) after film formation; (b) the product obtained in example 1 of the present invention was in the form after film formation and impact strength test. FIG. 1 shows that the coating film of the commercially available product cracks and falls off at an impact height of 80 cm; the product of example 1, however, exhibited cracking and peeling of the coating film only when the impact height was 100 cm. Thus, the impact strength of the product of example 1 was higher.

Fig. 2 is a method for inspecting corrosion resistance of a coating film using a neutral salt spray test. In order to quickly test the corrosion resistance of the coating film, a part of the coating film is firstly damaged, and then the corrosion condition of the metal plate is observed. In FIG. 2, (a) shows a form of a commercially available ketimine curing agent (Sunmide 3155) after a 14-day continuous salt spray test after film formation; (b) the product obtained in example 1 was in the form after a 14-day continuous salt spray test after film formation.

It is known from the test results that the corrosion of (a) is more severe, the width of the corrosion at the cross "x" is significantly wider than that of (b), and the degree of propagation of corrosion by the scratch is also more severe than that of (b). Therefore, the corrosion resistance of (b) is better.

As can be seen from Table 2, under the same test conditions, the pencil hardness of the commercial product was 3H, and the pencil hardness of the product of the present invention was 4H; in the impact test, the paint film of the commercial product was damaged at impact heights above 80cm, whereas the paint film of the product according to the invention did not significantly break at an impact height of 100cm (measured to a maximum of 100cm), see FIG. 1; in the salt spray resistance test, after 14 days of standing, the steel plates coated with the commercial products showed significant corrosion, while the steel plates coated with the products of the present invention showed corrosion at a significantly better level than the commercial products, as shown in fig. 2. In a whole, the pencil hardness, the shock resistance and the corrosion resistance of the product are obviously superior to those of products sold in the market, and the flexibility is equivalent, namely the performance of the product synthesized by the invention is obviously superior to those of the same type of products obtained in the market.

It should be noted that, although the technical solutions of the present invention are described by specific examples, those skilled in the art can understand that the present disclosure should not be limited thereto.

Having described embodiments of the present disclosure, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen in order to best explain the principles of the embodiments, the practical application, or improvements made to the technology in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

Industrial applicability

The amine-based curing agent of the present invention can be industrially produced and used for curing epoxy resins.