CN117624830A - Michael addition curable composition and use thereof, and method for preparing modified epoxy resin suitable for the composition - Google Patents

Michael addition curable composition and use thereof, and method for preparing modified epoxy resin suitable for the composition Download PDF

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Publication number
CN117624830A
CN117624830A CN202211030044.XA CN202211030044A CN117624830A CN 117624830 A CN117624830 A CN 117624830A CN 202211030044 A CN202211030044 A CN 202211030044A CN 117624830 A CN117624830 A CN 117624830A
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epoxy resin
michael addition
curable composition
addition curable
epoxy
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牛松
陈渭川
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Guangdong Huarun Paints Co Ltd
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Guangdong Huarun Paints Co Ltd
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Priority to CN202211030044.XA priority Critical patent/CN117624830A/en
Priority to PCT/CN2023/114532 priority patent/WO2024041581A1/en
Publication of CN117624830A publication Critical patent/CN117624830A/en
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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
    • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
    • C08G59/14—Polycondensates modified by chemical after-treatment
    • C08G59/1433—Polycondensates modified by chemical after-treatment with organic low-molecular-weight compounds
    • C08G59/1438—Polycondensates modified by chemical after-treatment with organic low-molecular-weight compounds containing oxygen
    • 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
    • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
    • C08G59/14—Polycondensates modified by chemical after-treatment
    • C08G59/1494—Polycondensates modified by chemical after-treatment followed by a further chemical treatment thereof
    • 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
    • C09D163/00—Coating compositions based on epoxy resins; Coating compositions based on derivatives of epoxy resins
    • 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
    • C09D4/00—Coating compositions, e.g. paints, varnishes or lacquers, based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; Coating compositions, based on monomers of macromolecular compounds of groups C09D183/00 - C09D183/16
    • C09D4/06—Organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond in combination with a macromolecular compound other than an unsaturated polymer of groups C09D159/00 - C09D187/00

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Materials Engineering (AREA)
  • Wood Science & Technology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Emergency Medicine (AREA)
  • Epoxy Resins (AREA)

Abstract

The present application relates to Michael addition curable compositions and their use, and to methods of preparing modified epoxy resins suitable for use in such compositions. Specifically, the Michael addition curable composition comprises: at least one reactive donor capable of providing two or more nucleophilic carbanions; at least one reactive acceptor comprising two or more carbon-carbon double bond groups; and at least one catalyst for catalyzing a Michael addition crosslinking reaction of the at least one reactive donor and the at least one reactive acceptor, wherein the at least one reactive donor comprises at least one epoxy resin-based reactive donor derived from at least one epoxy resin, and wherein the at least one epoxy resin-based reactive donorComprising at least one first-C (O) -CH 2 -C (O) -fragment and at least one second-C (O) -CH 2 -C (O) -fragments, wherein the at least one first-C (O) -CH 2 -C (O) -fragments are covalently bonded into the backbone of at least one epoxy resin, and said at least one second-C (O) -CH 2 -a C (O) -fragment is covalently bonded to a lateral end of the at least one epoxy backbone.

Description

Michael addition curable composition and use thereof, and method for preparing modified epoxy resin suitable for the composition
Technical Field
The present invention relates to a curable composition, and more particularly, to a Michael addition curable composition and its use, a coating composition comprising the composition, and a coated article made therefrom. The invention also relates to a method for preparing the epoxy resin-based reactive donor used for the composition.
Background
Due to increasingly stringent environmental regulations, the control standards for free diisocyanates (e.g., toluene diisocyanate TDI) and Volatile Organic Compounds (VOCs) in industrial applications are becoming increasingly stringent. In particular, TDI is extremely harmful to humans, and thus non-isocyanate (NICN) curing techniques without any free TDI are of great interest in both academic and industrial fields.
To date, there are several possible NICN curing methods in industrial applications, such as Polycarbodiimide (PCDI) curing, michael addition curing, etc. PCDI curing is difficult to commercialize at this stage due to the short pot life. At present, michael addition curing has been popularized and applied in the industrial field, and the Michael addition curing system has a plurality of advantages which are particularly attractive, including (1) that the Michael addition curing system can be constructed at room temperature or even lower temperature; (2) very low solvent content (e.g., less than 250 g/L); (3) The activation period is very long (e.g. greater than 8 hours at 23 ℃); (4) Excellent appearance properties (e.g., gloss greater than 90 at 60 °, doi greater than 90); (5) enabling thick layer coating (> 150 μm); (6) very good chemical resistance; (7) excellent flexibility; (8) good outdoor durability; and (9) is free of isocyanate, formaldehyde and organotin. Thus, the need in the marketplace for such Michael addition cure systems is vigorous.
From a compositional standpoint, a Michael addition curing system is typically composed of a reactive donor, a reactive acceptor, and a catalyst for catalyzing the Michael addition crosslinking reaction of the reactive donor and the reactive acceptor, as well as other additional components. Currently, the research on such curing systems has focused mainly on catalysts and on additional components of the system, with very limited research on reactive donors and reactive acceptors. In the disclosed Michael addition curing systems, the reactive functional groups of the reactive donor and the reactive acceptor are mostly of a single type, and thus the properties of the Michael addition reaction curing systems formulated therefrom are often also single, and cannot meet the increasing demands of the market on the properties of the coating compositions, in particular the curing properties, the coating properties.
Thus, there is a need in the industry for further improved Michael addition cure systems.
Disclosure of Invention
In one aspect, the invention discloses a Michael addition curable composition comprising:
at least one reactive donor capable of providing two or more nucleophilic carbanions;
at least one reactive acceptor comprising two or more carbon-carbon double bond groups; and
At least one catalyst for catalyzing the Michael addition crosslinking reaction of said at least one reactive donor and said at least one reactive acceptor,
wherein the at least one reactive donor comprises at least one epoxy resin based reactive donor derived from at least one epoxy resin, and
wherein the at least one epoxy-based reactive donor comprises at least one first-C (O) -CH 2 -C (O) -fragment and at least one second-C (O) -CH 2 -C (O) -fragments, wherein the at least one first-C (O) -CH 2 -C (O) -fragments are covalently bonded into at least one epoxy resin backbone, and the at least one second-C (O) -CH 2 -a C (O) -fragment is covalently bonded to a lateral end of the at least one epoxy backbone. Preferably, -C (O) -CH covalently bonded into the epoxy resin backbone 2 -C (O) -fragment and said-C (O) -CH covalently bonded to the lateral end of said epoxy resin backbone 2 -molar ratio of C (O) -fragments less than 1:1, but greater than 1:4, preferably at 1:1.5-2.5, preferably in the range of 1: 1.8-2.2.
In one embodiment of the invention, the at least one epoxy resin based reactive donor is obtained by a process comprising the steps of:
(i) Subjecting the epoxy resin to a ring opening reaction with malonic acid in the presence of at least one catalyst at a temperature below 130 ℃, preferably at a temperature of 90-120 ℃ until the acid value approaches 0mgKOH/g, thereby introducing secondary hydroxyl groups in the epoxy resin to form a reaction product; and is also provided with
(ii) Transesterification of the reaction product obtained in step i) with alkyl acetoacetates.
In certain embodiments of the present invention, the Michael addition curable composition may be used to prepare coatings, adhesives, sealants, foams, elastomers, films, molded articles, or inks.
In another aspect the invention provides a coating composition comprising a Michael addition curable composition according to the invention. In certain embodiments, the coating composition is applied at a wet coating thickness of 200 microns and dried for 1 day, the resulting cured coating having a chemical resistance of grade 4 or greater, preferably a chemical resistance of grade 5, as determined according to ASTM F2250-test method B.
In another aspect, the invention provides a coated article comprising a substrate having at least one major surface; and a cured coating, at least a portion of which is formed from the coating composition of the present invention applied directly or indirectly to the major surface. Preferably, the substrate comprises wood, metal, plastic, ceramic, cement board, glass, or any combination thereof.
The present invention provides in yet another aspect a method for preparing a modified epoxy resin, the method comprising the steps of: (i) Subjecting at least one epoxy resin to a ring opening reaction with malonic acid in the presence of at least one catalyst at a temperature below 130 ℃ until the acid value approaches 0mgKOH/g, thereby introducing secondary hydroxyl groups in the epoxy resin to form a reaction product; and (ii) transesterifying the reaction product obtained in step i) with an alkyl acetoacetate to obtain the modified epoxy resin, wherein the modified epoxy resin comprises at least one first-C (O) -CH 2 -C (O) -fragment and at least one second-C (O) -CH 2 -C (O) -fragments, wherein the at least one first-C (O) -CH 2 -C (O) -fragments are covalently bonded to at least one epoxy resin backboneAnd said at least one second-C (O) -CH 2 -a C (O) -fragment is covalently bonded to a lateral end of the at least one epoxy backbone. In certain embodiments of the present invention, the catalyst is selected from quaternary ammonium salts, quaternary phosphonium salts, or combinations thereof, preferably comprising tetraalkylammonium bromide.
In the present invention, the applicant successfully synthesized a catalyst having two or more-C (O) -CH 2 -modified epoxy resins of the C (O) -fragment, wherein the two or more-C (O) -CH 2 One of the-C (O) -fragments is covalently bonded into the epoxy resin backbone, and the two or more-C (O) -CH 2 The other of the C (O) -fragments is covalently bonded to the lateral end of the epoxy backbone and is successfully applied to michael addition cure systems as a reactive donor. The modified epoxy resin has higher active hydrogen density and proper polydispersity, thus being suitable for being used as a reactive donor of a Michael addition curing system, and the Michael addition curing system formed by the modified epoxy resin is obviously better in chemical resistance after curing. The novel structure of the polymer enlarges the selection window of the reactive donor of the Michael addition curing composition and enhances the application prospect of the Michael addition curing system.
The details of one or more embodiments of the invention are set forth in the description below. Other features, objects, and advantages of the invention will be apparent from the description and claims.
Definition of the definition
As used herein, the numerical terms "at least one" and "one or more" are used interchangeably. Thus, for example, a component comprising an additive may be interpreted as indicating that the component comprises "one or more" additives.
Where a composition is described as comprising or including a particular component, it is contemplated that optional components not referred to by the present invention are not excluded from the composition, and that the composition may consist or consist of the recited components, or where a method is described as comprising or including a particular process step, it is contemplated that optional process steps not referred to by the present invention are not excluded from the method, and that the method may consist or consist of the recited process steps.
For simplicity, only a few numerical ranges are explicitly disclosed herein. However, any lower limit may be combined with any upper limit to form a range not explicitly recited; and any lower limit may be combined with any other lower limit to form a range not explicitly recited, and any upper limit may be combined with any other upper limit to form a range not explicitly recited. Furthermore, each point or individual value between the endpoints of the range is included within the range, although not explicitly recited. Thus, each point or individual value may be combined as a lower or upper limit on itself with any other point or individual value or with other lower or upper limit to form a range that is not explicitly recited.
As used herein, the term "michael addition" refers to the nucleophilic addition reaction of a nucleophilic carbanion provided by a reactive donor with an electrophilic conjugated system in a reactive acceptor, such as a carbon-carbon double bond. The michael addition reaction generally follows the following reaction mechanism:
In the above-described reactive scheme, the R and R' substituents on the reactive donor are electron withdrawing groups, which render the hydrogen on the methylene group of the reactive donor acidic, and under the action of catalyst B, carbanions are formed, and the reactive acceptors are typically compounds such as α, β -unsaturated ketones, aldehydes, carboxylic acids, esters, nitriles, nitro groups, and the like.
When used in reference to a "reactive donor," the term "nucleophilic carbanion" refers to an active intermediate of a carbon having two or three strong electronegative groups attached thereto, and having a lone pair of electrons, which can include, but is not limited to, -NO 2 、-C(＝O)-、-CO 2 R 1 、-SO 2 -, -CHO, -CN and-CONR 2 Etc., wherein R is 1 And R is 2 Each independently represents an alkyl group. In some embodiments of the invention, the nucleophilic carbanionThe proton is derived from an acidic proton C-H in an activated methylene or methine group.
As used in reference to a "reactive acceptor," the term "carbon-carbon double bond group" refers to a structure containing a carbon-carbon double bond in the molecule, but does not include a benzene ring. Examples of carbon-carbon double bond groups include but are not limited to, -c=c-, -c=c-c≡c-, -c=c-CHO, -c=c-CO-, -c=c-C (O) O-, -c=c-CN.
As used herein, the term "epoxy-based reactive donor" refers to a reactive donor derived from an epoxy resin that is capable of providing two or more nucleophilic carbanions.
When used in reference to an "epoxy resin based reactive donor," the term "aromatic epoxy backbone" refers to a backbone structure derived from an epoxy resin having a closed aromatic ring or ring system that is rigid, as opposed to a flexible alkane or cycloalkyl, such as cyclohexyl. Examples of such aromatic ring structures include, but are not limited to, phenylene, naphthylene, biphenylene, fluorenylene, and indenyl groups, and heteroarylene groups (e.g., closed aromatic or aromatic-based cyclic hydrocarbons or ring systems in which one or more of the atoms in the ring are elements other than carbon, such as nitrogen, oxygen, sulfur, and the like).
When used in reference to an "epoxy resin based reactive donor," the term "ether oxygen bond-O-" refers to a structure-CH-present in the backbone structure of an epoxy resin 2 -O-C 6 H 4 -a flexible ether linkage.
When used in reference to an "epoxy-based reactive donor," the term "epoxide equivalent weight" (EEW) refers to the mass of the reactive donor containing 1 mole of epoxide groups. In general, the lower the epoxy equivalent, the more epoxy groups contained in the reactive donor and the higher the reactivity.
When used in reference to an "epoxy-based reactive donor," the term "glass transition temperature (Tg)" refers to the glass transition temperature of the reactive donor itself, as determined, for example, by differential scanning calorimetry.
When used in reference to an "epoxy-based reactive donor", the expression "-C (O) -CH 2 by-C (O) -fragment equivalent "is meant that the fragment contains 1mol of-C (O) -CH 2 Mass of the resin of the C (O) -fragment. The higher the equivalent weight, the lower the content of active hydrogen functional groups; the lower the equivalent weight, the higher the content of active hydrogen functional groups. In an embodiment of the invention, "-C (O) -CH 2 -C (O) -fragment equivalent "is calculated by: subtracting the reaction-generated small molecule substances, including but not limited to "water" and "alcohols", from all the raw materials used in preparing the resin to obtain the total resin amount, and then adding-C (O) -CH according to the introduction 2 The molar amount of starting material containing 1mol of-C (O) -CH is calculated 2 The mass of the resin of the-C (O) -fragment, i.e., the-C (O) -CH of the resulting resin 2 -C (O) -fragment equivalents.
When used in reference to a "reactive acceptor," the term "glass transition temperature (Tg)" refers to the glass transition temperature of a homopolymer formed by homopolymerization of the reactive acceptor molecule, as determined, for example, by differential scanning calorimetry.
The term "substantially free" of a component when used in reference to a "coating composition" means that the coating composition of the present invention comprises no more than 0.1 wt%, preferably no more than 0.05 wt%, more preferably no more than 0.01 wt% of the component, relative to the total weight of the coating composition.
When used in reference to a "Michael addition curable composition," the term "open time" refers to the time it takes for the resulting mixture after mixing the components of the composition to be applied to a test substrate at a particular temperature at a particular wet coating thickness (e.g., 100 microns) to achieve tack-free, e.g., by touching. In some embodiments, the tack-free time may also be tested by other methods known in the art.
When used in reference to a "Michael addition curable composition," the term "gel time" refers to the time it takes for the resulting mixture to reach a non-flowable gel state after the components of the composition are mixed at a particular temperature. In embodiments of the present invention, gel time is an important parameter for measuring the workability of a Michael addition curable composition.
The term "major surface" as used in the context of a substrate is a surface formed by the dimensions of a length and width of the substrate for providing decoration.
The term "on" when used in the context of "coating a coating composition on a major surface of a substrate" includes coating the coating composition directly or indirectly on a major surface of a substrate. In some embodiments of the invention, a coating composition according to the invention is applied directly to a major surface of a substrate to form a coating. In some embodiments of the present invention, one or more barrier or adhesion promoting layers may be present between the coating composition according to the present invention and the substrate.
The terms "comprising" and "including" and variations thereof, when appearing in the specification and claims, are not intended to be limiting.
The terms "preferred" and "preferably" refer to embodiments of the invention that may provide certain benefits in certain circumstances. However, other embodiments may be preferred under the same or other circumstances. In addition, recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the invention.
Detailed Description
In one aspect, embodiments of the present invention disclose a Michael addition curable composition comprising:
at least one reactive donor capable of providing two or more nucleophilic carbanions;
at least one reactive acceptor comprising two or more carbon-carbon double bond groups; and
at least one catalyst for catalyzing the Michael addition crosslinking reaction of said reactive donor and said reactive acceptor,
wherein the at least one reactive donor comprises at least one epoxy-based reactive donor and the at least one epoxy-based reactive donor comprises at least one first-C (O) -CH 2 -C (O) -fragment and at least one second-C (O)-CH 2 -C (O) -fragments, wherein the at least one first-C (O) -CH 2 -C (O) -fragments are covalently bonded into at least one epoxy resin backbone, and the at least one second-C (O) -CH 2 -a C (O) -fragment is covalently bonded to a lateral end of the at least one epoxy backbone. Preferably, at least one first-C (O) -CH covalently bonded to the epoxy resin backbone 2 -C (O) -fragment and at least one second-C (O) -CH covalently bonded to a lateral end of the epoxy resin backbone 2 -molar ratio of C (O) -fragments less than 1:1, and greater than 1:4, preferably at 1:1.5-2.5, preferably in the range of 1: 1.8-2.2.
Reactive donors
According to an embodiment of the present invention, the Michael addition curable composition comprises at least one reactive donor capable of providing two or more nucleophilic carbanions. As described above, nucleophilic carbanions are reactive carbon reactive intermediates, which typically have two or three strong electronegative groups attached and carry a pair of lone pair electrons. As examples of strong electronegative groups, one or more of the following may be selected: -NO 2 、-C(＝O)-、-CO 2 R 1 、-SO 2 -, -CHO, -CN and-CONR 2 Etc., wherein R is 1 And R is 2 Each independently selected from alkyl groups.
In an embodiment of the invention, the reactive donor comprises at least one epoxy-based reactive donor. The reactive donor is derived from an epoxy resin and further comprises two or more-C (O) -CH 2 -C (O) -fragments to provide nucleophilic carbanions to act as reactive donors. The inventors of the present invention have surprisingly found that a michael addition cure system made with such reactive donors has an adjustable cure rate, e.g. its tack-free time can be controlled within a suitable period of time, e.g. 1.5 hours, and the resulting coating has significantly better chemical resistance.
According to an embodiment of the present invention, the epoxy resin based reactive donor refers to a reactive donor derived from an epoxy resin, such an epoxy resin based reactive donorThe stress donor comprises two or more of-C (O) -CH 2 -C (O) -fragment. As described above, in the currently available michael addition curable systems, the reactive functional groups of the reactive donor are mostly of a single type, and thus the properties of the michael addition reaction curable systems formulated therefrom are often also single, and cannot meet the increasing demands of the market on the properties of the coating compositions, in particular, the curing properties, coating properties. The inventors of the present application have surprisingly found that the incorporation of two or more-C (O) -CH in the epoxy resin based reactive donor according to the present invention 2 -C (O) -fragments, wherein the two or more-C (O) -CH 2 One of the-C (O) -fragments is covalently bonded into the epoxy resin backbone, and the two or more-C (O) -CH 2 The other of the C (O) -segments being covalently bonded to the lateral ends of the epoxy resin backbone may allow for a michael addition cure system formulated therefrom having significantly improved cure properties, such as significantly increased pot life.
In one embodiment according to the invention, the-C (O) -CH covalently bonded into the epoxy resin backbone 2 the-C (O) -fragment may be derived from malonic acid; and the-C (O) -CH covalently bonded to the side end of the epoxy resin backbone 2 the-C (O) -fragment may be derived from alkyl acetoacetates. Due to-C (O) -CH derived from malonic acid 2 Reactivity of the-C (O) -fragment with-C (O) -CH derived from alkyl acetoacetate 2 The reactivity of the-C (O) -fragments is different and thus contains both of the above-mentioned-C (O) -CH 2 The epoxy-based reactive donors of the-C (O) -segments have adjustable reactivity, which in turn results in a controllable cure rate of the michael addition cure system formulated therefrom, which is of great significance to the coating industry.
In some embodiments according to the invention, two or more-C (O) -CH's contained in the epoxy resin-based reactive donor 2 the-C (O) -fragment may have a specific molar ratio, wherein-C (O) -CH is covalently bonded into the epoxy resin backbone 2 -C (O) -fragments-C (O) at the lateral end covalently bonded to the epoxy backbone)-CH 2 -C (O) -fragments and-C (O) -CH covalently bonded into the epoxy resin backbone 2 The proportion of the combination of both-C (O) -fragments is relatively large. That is, -C (O) -CH covalently bonded into the epoxy resin backbone 2 The content of the-C (O) -fragment is-C (O) -CH at the side end thereof covalently bonded to the epoxy resin skeleton, although it is not the vast majority thereof 2 The ratio of the sum of the-C (O) -fragments is significant, i.e. at least 20%. Specifically, in at least one epoxy resin-based reactive donor according to an embodiment of the present invention, the-C (O) -CH covalently bonded into the epoxy resin backbone 2 -C (O) -fragment and said-C (O) -CH covalently bonded to the lateral end of said epoxy resin backbone 2 -molar ratio of C (O) -fragments less than 1:1, but greater than 1:4, preferably at 1:1.5-2.5, preferably in the range of 1: 1.8-2.2.
if-C (O) -CH covalently bonded to the lateral end of the epoxy resin backbone in the resulting epoxy resin based reactive donor 2 If the ratio of the C (O) -segment is too large, the curing speed of the Michael addition curable composition prepared from the C (O) -segment is too high, the pot life is too short, and the construction is difficult; if-C (O) -CH is covalently bonded to the epoxy resin backbone in the resulting epoxy resin based reactive donor 2 If the ratio of the C (O) -segments is too large, the Michael addition curable composition formulated therefrom will have too long a cure time and will be too economically disadvantageous.
According to an embodiment of the invention, the epoxy resin based reactive donor is a reactive donor derived from an epoxy resin, as described above. In particular, the epoxy resin-based reactive donor may be derived from an aromatic epoxy resin, which may comprise at least one aromatic epoxy backbone. Preferably, the aromatic epoxy backbone is derived from bisphenol a epoxy resin, bisphenol F epoxy resin, phenolic epoxy resin, and mixtures or combinations thereof. Suitable aromatic epoxy resins that can be functionalized to act as reactive donors include, but are not limited to, bisphenol a epoxy resins, bisphenol F epoxy resins, and novolac epoxy resins. As described above, the aromatic structure in the epoxy backbone of the reactive donor has a rigid structure. The inventors of the present invention have surprisingly found that the incorporation of aromatic rings or aromatic ring systems having a rigid structure in the epoxy backbone of a reactive donor can provide cured coatings with improved hardness compared to michael addition cured coatings having flexible alkyl or cycloalkyl groups (e.g., from Allnex act cured coatings).
According to embodiments of the present invention, the epoxy-based reactive donor may also contain at least one ether oxygen linkage (-O-). As described above, the ether oxygen bond in the epoxy-based reactive donor has flexibility. The inventors of the present invention have surprisingly found that the incorporation of flexible ether oxygen linkages in the epoxy backbone of the reactive donor can provide cured coatings with improved toughness.
It is well known in the art of synthesis that methods of functionalizing resins to form reactive donors suitable for use in Michael addition cure systems generally involve transesterifying resins having hydroxyl groups with alkyl acetoacetates or dialkyl malonates. However, it is impossible to form a film containing two or more of-C (O) -CH by the above-mentioned method 2 Modified resins of the-C (O) -fragments, which are more incapable of controlling different species-C (O) -CH 2 -molar ratio of C (O) -fragments. The inventors of the present application have provided a novel method for synthesizing a reactive donor such that two or more-C (O) -CH contained in an epoxy resin-based reactive donor obtained therefrom 2 The C (O) -fragment has a specific molar ratio and can thus be used industrially.
In one embodiment of the invention, the at least one epoxy resin based reactive donor is obtained by a process comprising the steps of: (i) Subjecting the epoxy resin to a ring opening reaction with malonic acid in the presence of at least one catalyst at a temperature below 130 ℃, preferably at a temperature of 90-120 ℃ until the acid value approaches 0mgKOH/g, thereby introducing secondary hydroxyl groups in the epoxy resin; and (ii) transesterifying the product obtained in step i) with an alkyl acetoacetate. Preferably, the at least one alkyl acetoacetate comprises at least one C acetoacetate 1 -C 8 Alkyl esters.
The inventors of the present invention have surprisingly found that by the above method, -C (O) -CH2-C (O) -fragments can be distributed not only in the middle of the backbone structure of the epoxy resin, but also at the lateral ends of the backbone of the epoxy resin. Epoxy resins of this structure were first successfully synthesized by the applicant of the present application and successfully applied in michael addition cure systems. No prior art prior to this application discloses and teaches this novel epoxy resin and its use in a michael addition cure system. Thus, the novel epoxy resin according to embodiments of the present invention expands the window of choice for the reactive donors of the Michael addition curable composition, widening the range of applications of Michael addition curable compositions. Furthermore, the inventors of the present invention have surprisingly found that the density of-C (O) -CH2-C (O) -fragments in epoxy resin based reactive donors is significantly increased by the above method. At the same time, the above process is more controllable than the process of transesterifying the hydroxyl groups of the epoxy resin with alkyl acetoacetates and/or dialkyl malonates, and the modified epoxy resins obtained therefrom have suitably also narrower polydispersity. Thus, the modified epoxy resins obtained by the above-described process can significantly increase the crosslink density of the resulting coating when used as a reactive donor for a Michael addition cure system, thus increasing the chemical resistance of the coating.
In an embodiment according to the invention, the at least one epoxy resin based reactive donor has a polydispersity, as determined by GPC, in the range of 1.0 to 3.5, preferably in the range of 1.0 to 3.2, more preferably in the range of 1.1 to 3.0. Moreover, in an embodiment according to the invention, the weight average molecular weight of the at least one epoxy resin based reactive donor is in the range of 500g/mol to 15000g/mol, preferably in the range of 500g/mol to 10000g/mol, more preferably in the range of 500g/mol to 8000g/mol, still more preferably in the range of 500g/mol to 5000g/mol, as determined by GPC.
According to embodiments of the present invention, the epoxy-based reactive donor may have a specific epoxy equivalent. The inventors of the present invention have surprisingly found that the epoxy equivalent of the epoxy resin based reactive donor is directly related to the VOC of the coating composition, which was not appreciated prior to the present application. Without being bound by any theory, the inventors speculate that this may be due to the fact that the epoxy equivalent is related to the viscosity of the epoxy resin, with higher epoxy equivalent corresponding to higher resin viscosity. Thus, an epoxy resin with a lower epoxy equivalent can film better with the aid of a smaller solvent, and thus, emit less VOC content. According to an embodiment of the present invention, the epoxy equivalent of the epoxy resin based reactive donor may be in the range of 400-1100g/mol, preferably in the range of 470-1000g/mol, more preferably in the range of 470-900g/mol, still more preferably in the range of 560-885 g/mol.
According to embodiments of the present invention, the epoxy-based reactive donor may have a relatively high glass transition temperature. The inventors of the present invention have found that increasing the glass transition temperature of an epoxy-based reactive donor is advantageous for increasing the hardness of the cured coating. In one embodiment of the invention, the epoxy-based reactive donor has a glass transition temperature of 25 ℃ or higher. However, in view of practical application, the glass transition temperature of the epoxy-based reactive donor should not be too high, which would otherwise affect the curing of the coating and would bring about unnecessary VOC emissions. Thus, the epoxy-based reactive donor according to the invention preferably has a glass transition temperature in the range of 25 ℃ to 40 ℃.
The amount of epoxy resin-based reactive donor as reactive donor in the Michael addition curable composition according to the present invention may vary within wide limits as desired. In some embodiments of the present invention, the michael addition curable composition comprises, relative to the total weight of the main agent (composed of the remaining components excluding the catalyst and diluent) of the michael addition curable composition, from 48 to 80% by weight of the epoxy-based reactive donor as a reactive donor, preferably from 49 to 70% by weight of the epoxy-based reactive donor as a reactive donor.
Reactive receptors
According to an embodiment of the present invention, a Michael addition curable composition comprises a reactive acceptor containing two or more carbon-carbon double bond groups.
According to an embodiment of the invention, the reactive acceptor has a relatively low molecular weight, typically in a non-polymeric form. Preferably, the reactive acceptor has a molar mass of 1000g/mol or less, preferably 500g/mol or less, more preferably 350g/mol or less.
According to an embodiment of the invention, the reactive acceptor comprises a carbon-carbon double bond group having a structure represented by formula I:
c=c-CX (formula I)
Wherein CX represents any one of alkenyl, alkynyl, aldehyde group (-CHO), ketone group (-CO-), ester group (-C (O) O-) and cyano group (-CN). Preferably, the carbon-carbon double bond group is derived from one or more of an α, β -unsaturated aldehyde, α, β -unsaturated ketone, α, β -unsaturated carboxylic acid ester and α, β -unsaturated nitrile, preferably from an α, β -unsaturated carboxylic acid ester.
In one embodiment of the present invention, the reactive acceptor may be selected from one or more of α, β -unsaturated carboxylic acid esters represented by the following formula:
in a preferred embodiment of the present invention, the reactive acceptor may be selected from one or more of α, β -unsaturated carboxylic acid esters represented by formulas a and C.
The amount of reactive acceptors in the Michael addition curable composition according to the present invention can be varied as desired over a wide range. In some embodiments of the present invention, the Michael addition curable composition contains, relative to the total weight of the main agent (composed of the remaining components excluding the catalyst and diluent) of the Michael addition curable composition, 20 to 48% by weight of the reactive acceptor, preferably 30 to 45% by weight of the reactive acceptor.
Catalyst
In addition to the above components, the Michael addition curable composition according to the present invention further comprises a catalyst for catalyzing the Michael addition crosslinking reaction of the reactive acceptor and the reactive donor.
In certain embodiments of the invention, the catalyst comprises a latent base catalyst.
In one embodiment of the present invention, the latent base catalyst described herein is a substituted carbonate having the structure of formula (II):
in formula (II):
X + is a non-acidic cation. As examples of the non-acidic cation, alkali metal ions, alkaline earth metal ions, ammonium ions, phosphonium ions, and the like can be used, but are not limited thereto. Preferably X + Lithium ion, sodium ion, potassium ion, or the like. More preferably X + Is a quaternary ammonium ion or a phosphonium ion;
r is H, optionally substituted C1-10 alkyl, C6-12 aryl, C7-C14 aralkyl, C7-C14 alkaryl, or a combination thereof. Preferably, R is an unsubstituted alkyl group having 1 to 4 carbon atoms. If the R group is substituted, the substituents are selected so as not to substantially interfere with the crosslinking reaction. To avoid interfering with the action of the base catalyst, acidic substituents (e.g., carboxylic acid substituents) are present only in an unreactive amount or are not present at all.
In one embodiment, the latent base catalyst described herein is a compound having the general structure shown in formula (II) wherein the cation X + The latent base catalyst is linked in a single molecule to a carbonate group of formula (II), i.e. has the general structure of formula (II-1):
wherein X is + And R is as defined above.
In another embodiment, the latent base catalyst described herein is a compound of the general structure shown in formula (II) wherein the group R is a polymer, and/or the cation X + Is a quaternary ammonium ion or a phosphonium ion.
In a preferred embodiment, the latent base catalyst described herein is preferably a quaternary alkyl ammonium carbonate. Suitable examples include, but are not limited to, tetrahexylammonium methyl carbonate, tetradecyl-trihexylammonium methyl carbonate, tetra decylammonium methyl carbonate, tetrabutylammonium ethyl carbonate, benzyltrimethylammonium methyl carbonate, trihexylmethylammonium methyl carbonate, or trioctylmethylammonium methyl carbonate, and mixtures or combinations thereof.
Preferably, the latent base catalysts described herein comprise tetrabutylammonium alkyl carbonate. Latent catalysts of this type are known in the art. For example, the commercially available form of the latent catalyst described herein is referred to as A-CURE 500 (Allnex, frankflirt, germany).
Without being limited by theory, the latent base catalyst of formula (II) acts by releasing carbon dioxide upon decomposition of the carbonate. This gives rise to a strong base, i.e. a hydroxide, an alkoxy base or an aralkoxy base. In the storage tank, the reaction proceeds slowly, thereby extending the pot life. As the surface area increases after the coating composition is applied, the alkali regenerates rapidly as carbon dioxide escapes from the surface, allowing the coating to cure more quickly (i.e., dry and develop hardness). Thus, the use of a latent base catalyst of formula (II) allows for optimal pot life, open time and curing properties of the coating compositions described herein.
In other embodiments of the present invention, the catalyst may also comprise conventional catalysts (i.e., non-latent catalysts) other than the latent base catalysts described above, known to those skilled in the art, which may be used alone or in combination with the latent base catalysts described herein to accelerate the Michael addition reaction.
Examples of suitable non-latent catalysts include, but are not limited to, tetrabutylammonium hydroxide (TBAH), ammonium hydroxide, DBU (8-diazabicyclo [5.4.0] undec-7-ene), DBN (1, 5-diazabicyclo [4.3.0] non-5-ene), and TMG (1, 3-tetramethylguanidine).
Other examples of suitable non-latent catalysts include, but are not limited to, salts of cation and anion pairing, including non-acidic cations, such as K + 、Na + 、Li + The method comprises the steps of carrying out a first treatment on the surface of the Or a weakly acidic cation, such as a protonated species of a strong organic base (DBU, DBN, TMG or TBAH), the anion being a basic anion X-from a compound containing an acidic XH group, wherein X comprises N, P, O, S, C or Cl. As an illustrative example of such a non-latent catalyst may be tetrabutylammonium fluoride.
In one embodiment, the amount of catalyst used herein may vary depending on the nature of the composition. Preferably, the catalyst is present in an amount of 1.0 parts by weight or more, preferably 1.4 parts by weight or more and not more than 10 parts by weight, preferably not more than 8 parts by weight, still more preferably not more than 5 parts by weight, based on the solid amount of the catalyst, relative to 100 parts by weight of the main agent (composed of the rest of the components excluding the catalyst and the diluent) in the michael addition curable composition.
Other components
The Michael addition curable compositions according to embodiments of the present invention may further comprise at least one solvent (including a diluent) to adjust the viscosity of the composition to achieve desired processability.
In certain embodiments of the invention, the solvent comprises one or more of an alcoholic solvent (e.g., methanol, isopropanol, isobutanol, n-propanol, n-butanol, 2-butanol, pentanol, t-amyl alcohol, neopentyl alcohol, n-hexanol, ethylene glycol, etc.), an ester solvent (e.g., ethyl acetate, butyl acetate, propyl methoxyacetate, isobutyl acetate, propylene glycol methyl ether acetate, etc.), a ketone solvent (e.g., methyl ethyl ketone, methyl n-amyl ketone, etc.), an ether solvent (e.g., ethylene glycol butyl ether, etc.), an aliphatic hydrocarbon solvent (e.g., solvent oil, etc.), and an aromatic and/or alkylated aromatic hydrocarbon solvent (e.g., toluene, xylene, etc.).
In a specific embodiment of the present invention, the solvent comprises one or more of isopropanol, propylene glycol methyl ether acetate, ethyl acetate, and butyl acetate.
In embodiments according to the present application, the amount of solvent may vary within wide limits. The solvent is preferably varied in the range of 0.1 to 35 parts by weight, more preferably 10 to 30 parts by weight, still more preferably 15 to 30 parts by weight, even more preferably 25 to 30 parts by weight, relative to 100 parts by weight of the main agent in the michael addition curable composition.
In embodiments of the present invention, the compositions of the present invention may optionally further comprise other additional additives commonly used in compositions that do not adversely affect the composition or the cured product resulting therefrom. Suitable additives include, for example, those agents that improve the processability or manufacturability of the composition, enhance the aesthetics of the composition, or improve specific functional properties or characteristics (such as adhesion to a substrate) of the composition or a cured product derived therefrom. Additives may be included, for example, selected from one or more of adhesion promoters, cure promoters, open time modifiers, pigments and fillers, surfactants, lubricants, defoamers, dispersants, leveling agents, UV absorbers, colorants, coalescing agents, thixotropic agents, antioxidants, stabilizers, preservatives and bactericides to provide the desired properties as desired. The amount of each optional ingredient is preferably sufficient to achieve its intended purpose without adversely affecting the composition or the cured product derived therefrom.
Michael addition curable composition
According to the examples of the present invention, after mixing the components of the composition of the present invention, the resulting mixture has a considerably long pot life, showing particularly excellent workability. In one embodiment of the invention, after mixing the components of the composition, the resulting mixture has a pot life of 6 hours or more, preferably 7 hours or more, more preferably 8 hours or more, even more preferably 10 hours or more at 25 ℃.
The Michael addition curable composition of the present invention may be used to select an appropriate curing temperature depending on the requirements, such as the material of the coated substrate. In certain embodiments, the curing is performed at room temperature, specifically, in a temperature range of 20-40 ℃, preferably 25-35 ℃. In other embodiments, the curing may be under high temperature bake conditions, such as conditions above 100 ℃.
The cure time of the Michael addition curable composition of the present invention is related to the cure temperature. In some embodiments according to the present invention, the Michael addition curable composition of the present invention can achieve tack-free in 2 hours or less, preferably in 1.8 hours or less, more preferably in 1.5 hours or less, under room temperature curing conditions. In other embodiments according to the present invention, the Michael addition curable composition of the present invention has a gel time of 25 minutes or more, preferably 30 minutes or more, more preferably 35 minutes or more, at room temperature.
The Michael addition curable compositions of the embodiments herein are useful in a variety of applications, and may be used to prepare coatings, adhesives, sealants, foams, elastomers, films, molded articles, or inks.
According to certain embodiments of the present invention, the Michael addition curable composition, prior to use: the components thereof, such as the reactive donor, the reactive acceptor and the catalyst, should be stored separately, or some of the components may be pre-mixed, for example, the reactive donor and the reactive acceptor may be pre-mixed, the catalyst may be stored separately, and for example, the catalyst may be pre-mixed with the reactive donor or the reactive acceptor, and the other reactive donor or the reactive acceptor, which is not pre-mixed with the catalyst, may be stored separately. When in use: the reactive donor, reactive acceptor and other components are simply mixed in a mixing device in a predetermined weight ratio. The mixed curable composition may be formed using various methods familiar to those skilled in the art, such as by molding, coating, extrusion, and the like. The composition thus obtained can be cured to form a desired cured product. Thus, the present invention also relates to a cured product obtainable by the Michael addition curable composition of the present invention and/or a cured product obtainable by the Michael addition curable composition of the present invention.
Coating composition
The Michael addition curable composition according to the invention is particularly suitable for application in the coating industry as a coating composition. Accordingly, another aspect of an embodiment of the present invention relates to a coating composition comprising the Michael addition curable composition according to the present invention as a film-forming resin.
In certain embodiments, the coating compositions of the present invention comprise:
the main agent comprises the following components: at least one reactive donor capable of providing two or more nucleophilic carbanions, at least one reactive acceptor comprising two or more carbon-carbon double bond groups, and optionally additional additives, such as thickeners, wetting agents, leveling agents, defoamers, dispersants, pH modifiers, mildewcides, preservatives, or any combination thereof;
catalyst: at least one catalyst for catalyzing the Michael addition crosslinking reaction of said reactive donor and said reactive acceptor; and
solvents including isopropanol, propylene glycol methyl ether acetate, ethyl acetate, butyl acetate, or combinations thereof.
In certain embodiments according to the present invention, after mixing the components of the coating composition of the present invention, the resulting mixture has a suitable pot life, exhibiting particularly excellent workability. In one embodiment of the invention, after mixing the components of the coating composition, the resulting mixture has a pot life of 4-24 hours at 25 ℃, preferably 6-18 hours, more preferably 8-18 hours.
In certain embodiments according to the present invention, after coating the coating composition according to the present invention at a wet coating thickness of 200 microns and drying for 1 day, the resulting cured coating has a chemical resistance of grade 4 or higher, preferably a chemical resistance of grade 5, as determined according to ASTM F2250-test method B.
In certain embodiments according to the present invention, after coating the coating composition according to the present invention at a wet coating thickness of 200 microns and drying for 1 day, the resulting cured coating has a hardness of 2B or more, preferably a hardness of B or more, more preferably a hardness of HB or more, still more preferably a hardness of H or more, the hardness being pencil hardness.
In certain embodiments according to the present invention, after coating the coating composition according to the present invention at a wet coating thickness of 200 micrometers and drying for 1 day, the resulting cured coating has a toughness of 10mm or less, preferably a toughness of 5mm, as determined according to GB/T1731-2020.
In embodiments of the Michael addition curable compositions according to the present invention as coating compositions, the compositions may be applied by a variety of methods familiar to those skilled in the art, including spraying (e.g., air-assisted, airless, or electrostatic spraying), brushing, rolling, flood coating, and dipping. In one embodiment of the invention, the mixed cured coating composition is applied by spraying. The cured coating composition can be applied to a variety of wet film thicknesses. In embodiments of the present invention, the wet film thickness is preferably in the range of about 100 to about 400 μm, preferably in the range of 100-200 μm. The applied coating may be cured by allowing it to air dry (room temperature) or by accelerating the curing using various drying means (e.g. ovens) familiar to those skilled in the art.
Coated article
In another aspect of the invention, there is provided a coated article comprising: a substrate having at least one major surface; and a cured coating formed from a coating composition according to the invention applied directly or indirectly on the major surface.
According to the invention, the substrate has at least one, preferably two, main surfaces which are opposite to each other. As used herein, a "major surface" is a surface for decoration formed by the length and width dimensions of a substrate. Preferably, the main surface of the substrate may have polar groups such as hydroxyl groups, amino groups, mercapto groups, and the like, to promote adhesion of the coating. The hydroxyl groups on the surface of the substrate may be derived from the substrate itself (cellulose in a wood substrate in the case of a wood substrate) or may be obtained by a surface treatment method such as oxidation by corona treatment, thereby introducing hydroxyl groups on the surface of the substrate.
According to the invention, the coated article may be based on a substrate of various application structures. Examples of suitable application structures include, but are not limited to, natural and engineered building and construction materials, freight containers, flooring materials, furniture, walls, other construction materials, motor vehicles, motor vehicle components, aircraft components, trucks, rail cars, bridges, water towers, cell phone base stations, windmills, lighting devices, billboards, fences, tunnels, pipes, marine components, machine components, laminates, packaging materials, and the like. Suitable substrate materials include, but are not limited to, wood, metal, plastic, ceramic, cement board, or any combination thereof.
Preparation method of modified epoxy resin
As described above, the applicant of the present application succeeded in synthesizing a modified epoxy resin in which a-C (O) -CH2-C (O) -fragment is distributed not only in the middle of the skeleton structure of the epoxy resin but also at the side ends of the skeleton of the epoxy resin for the first time using a novel method. Accordingly, in another aspect of the present invention, there is provided a novel process for preparing a modified epoxy resin, the process comprising the steps of:
(i) Subjecting at least one epoxy resin to a ring opening reaction with malonic acid in the presence of at least one catalyst at a temperature below 130 ℃ until the acid value approaches 0mgKOH/g, thereby introducing secondary hydroxyl groups in the epoxy resin to form a reaction product; and is also provided with
(ii) Transesterification of the reaction product obtained in step i) with alkyl acetoacetate to form said modified epoxy resin,
wherein the modified epoxy resin comprises at least one first-C (O) -CH 2 -C (O) -fragment and at least one second-C (O) -CH 2 -C (O) -fragments, wherein the at least one first-C (O) -CH 2 -C (O) -fragments are covalently bonded into the backbone of at least one epoxy resin, and said at least one second-C (O) -CH 2 -a C (O) -fragment is covalently bonded to a lateral end of the at least one epoxy backbone.
In a preferred embodiment of the above process, the ring-opening reaction of the epoxy resin with malonic acid is carried out at a temperature of 90-120 ℃.
In a preferred embodiment of the above process, the catalyst is selected from quaternary ammonium salts, quaternary phosphonium salts or combinations thereof, preferably comprising tetraalkylammonium bromide.
The present disclosure is more particularly described in the following examples that are intended as illustrations only, since various modifications and changes within the scope of the present disclosure will be apparent to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported in the examples below are by weight, and all reagents used in the examples are commercially available and can be used directly without further processing.
Examples
Test method
Gel time: samples of the Michael addition curable composition or coating composition were placed in glass bottles at 25.5℃open and the time elapsed until the viscosity reached 2 times the initial viscosity was measured using rock No. 2 Tian Bei.
Surface drying time: the Michael addition curable composition or coating composition is applied to the surface to be coated at 25.5℃to form a 200 μm wet film, and dried to the point of not sticking to the hands, which can be measured according to GB 1728-2020.
Hardness: the pencil hardness of the coating was measured after 7 days of drying after knife coating of a 200 μm wet film at 25.5 ℃.
Toughness: after doctor-coating a 200 μm wet film at 25.5℃and drying for 7 days, the toughness is measured according to the method of GB/T1731-2020 using a mandrel bend, wherein the toughness is measured in terms of the diameter of the mandrel. Generally, the smaller the diameter of the shaft rod, the better the toughness of the coating.
Chemical resistance: after knife coating of 200 μm wet film at 25.5℃it was dried for 7 days. The resulting coating was subjected to acetic acid for 1 hour, soda ash (50 g/L) for 2 hours, alcohol (70%) for 1 hour, cold water for 24 hours, boiling water for 30 minutes and/or 5 cycle cold check according to ASTM F2250-test method B to evaluate the chemical resistance of the coating. Finally, the integrity of the coating is determined. Chemical resistance is generally classified into a scale of 0 to 5, where 5=coating is intact, no stain, no delamination (best), 4=coating stains are hardly noticeable, 3=coating stains can be clearly confirmed, 2=coating discoloration and foaming, softening, etc., 0=coating large bubbles, delamination tendency, etc. (worst).
Reactive donors
Modified epoxy resin A1：
702.50g of epoxy resin (CCP BE188EL, liquid epoxy resin at room temperature) and 6.93g of catalyst (tetrabutylammonium bromide) were charged into a four-necked flask equipped with a thermometer, overhead stirrer, air-inlet and reflux apparatus at room temperature. N2 protection is provided by providing N2 gas through the gas inlet. The mixture was then slowly heated to 80 ℃, 183.85g malonic acid was slowly added, controlling the exotherm in the range of 80-100 ℃. After the addition of malonic acid was completed, the temperature was kept at 100℃until the solid acid value was close to 0mgKOH/g.
When the above acid number was close to 0, 498.16g of t-butyl acetoacetate (t-BAA) was added to the mixture. The reaction mixture was then slowly heated to about 110 ℃, the distillate (t-butanol) was collected and maintained at this temperature until the distillation temperature did not exceed 78 ℃. Under such conditions (distillation temperature<=78℃), the temperature of the mixture was raised to 180 ℃. When the temperature of the mixture reached 180 ℃, the temperature was maintained until the distillation temperature was below 60 ℃. The mixture was then cooled to below 120℃and then admixed with 428.56g of n-butyl acetate (n-BA). About 72% solids, 500 to 5000 molecular weight, polydispersity of 1.1 to 3, -C (O) -CH derived from malonic acid 2 -C (O) -fragment and-C (O) -CH derived from t-BAA 2 The molar ratio of the-C (O) -fragment was 0.56. Based on liquid resins, final active hydrogen (-C (O) -CH 2 The equivalent of the-C (O) -fragment is about 165.82g/mol.
Modified epoxy resin A2: 789.80g of epoxy resin (Nanya NEPS901, solid epoxy resin at room temperature), 83.19g of n-butyl acetate (n-BA) and 6.90g of catalyst (tetrabutylammonium bromide) were charged into a four-necked flask equipped with a thermometer, overhead stirrer, gas inlet and reflux apparatus at room temperature. N2 protection is provided by providing N2 gas through the gas inlet. The mixture was then slowly heated to 100℃and 72.71g malonic acid was slowly added, controlling the exotherm in the range of 100-110 ℃. After the addition of malonic acid was completed, the temperature was kept at 100℃until the solid acid value was 0mgKOH/g.
When the above acid value was 0, 500.90g of t-butyl acetoacetate (t-BAA) was added to the mixture. The reaction mixture was then slowly heated to about 110 ℃, the distillate (t-butanol) was collected and maintained at this temperature until the distillation temperature did not exceed 78 ℃. Under such conditions (distillation temperature<=78℃), the temperature of the mixture was raised to 180 ℃. When the temperature of the mixture reached 180 ℃, the temperature was maintained until the distillation temperature was below 60 ℃. The mixture was then cooled to below 120℃and then mixed with 339.61g of n-butyl acetate (n-BA). About 72% solids, 500 to 5000 molecular weight, polydispersity of 1.1 to 3, -C (O) -CH derived from malonic acid 2 -C (O) -fragment and-C (O) -CH derived from t-BAA 2 The molar ratio of the-C (O) -fragment was 0.22. Based on liquid resins, final active hydrogen (-C (O) -CH 2 The equivalent of the-C (O) -fragment is about 202.49g/mol.
Modified epoxy resin A3：
875.13g of epoxy resin (Nanya NEPS902, solid epoxy resin at room temperature), 69.80g of n-butyl acetate (n-BA) and 7.49g of catalyst (tetrabutylammonium bromide) were charged at room temperature into a four-necked flask equipped with a thermometer, overhead stirrer, gas inlet and reflux apparatus. N2 protection is provided by providing N2 gas through the gas inlet. The mixture was then slowly heated to 100 ℃, 61.00g malonic acid was slowly added to control the exotherm in the range of 100-110 ℃. After the addition of malonic acid was completed, the temperature was kept at 100℃until the solid acid value was 0mgKOH/g.
When the above acid value was 0, 420.28g of t-butyl acetoacetate (t-BAA) was added to the mixture. The reaction mixture was then slowly heated to about 110 ℃, the distillate (t-butanol) was collected and maintained at this temperature until the distillation temperature did not exceed 78 ℃. Under such conditions (distillation temperature<=78℃), the temperature of the mixture was raised to 180 ℃. When the temperature of the mixture reached 180 ℃, the temperature was maintained until the distillation temperature was below 60 ℃. The mixture was then cooled to below 120℃and then mixed with 358.80g of n-butyl acetate (n-BA). About 72% solids, 500 to 5000 molecular weight, polydispersity of 1.1 to 3, -C (O) -CH derived from malonic acid 2 -C (O) -fragment and-C (O) -CH derived from t-BAA 2 The molar ratio of the-C (O) -fragment was 0.22. Based on liquid resins, final active hydrogen (-C (O) -CH 2 The equivalent of the-C (O) -fragment is about 247.16g/mol.
Reactive receptors
Table 1: various reactive receptors
Catalyst
Catalyst C1: acure 500 commercially available from Allnex.
Catalyst C2: tetrabutylammonium fluoride 30% aqueous solution.
Coating composition
EXAMPLE 1 Michael addition curable composition
The components constituting component a were mixed in the amounts shown in table 2 below to form component a, and then component a, component B and component C were mixed in the amounts shown in table 2 below to form coating compositions 1-1 to 1-12 suitable for forming michael addition cured coatings.
The compositions formulated in the examples shown in table 1 below were each applied to a test substrate at a wet coating thickness of 200 microns and cured at room temperature, recording the length of time required for curing. The term "cure" is used herein to mean that the coating has reached tack free, also known as "tack free time", to the touch. And the hardness, toughness and chemical resistance of the coating were tested according to the specifications of the test section.
Table 2: compositions 1-1 to 1-6 have the composition and properties of the resulting coating
Table 2 (continuation): compositions 1-7 to 1-12 and the properties of the resulting coatings
From the results of Table 2 above, it can be seen that the modified epoxy resins according to the present invention can be combined with various reactive acceptors, and different catalysts to form a Michael addition curable system, and the resulting Michael addition curable composition can be cured at room temperature. Furthermore, the applicant of the present invention successfully synthesized for the first time a modified epoxy resin having both active hydrogen derived from malonic acid and active hydrogen derived from alkyl acetoacetate using a ring-opening reaction is equally suitable for formulating a Michael addition curable composition with certain catalysts, such as Acure 500, and the resulting cured composition also exhibits an appropriate cure speed and the resulting coating also exhibits appropriate toughness, hardness and chemical resistance.
While the invention has been described with reference to a number of embodiments and examples, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope and spirit of the invention as disclosed herein.

Claims (24)

1. A michael addition curable composition comprising:
at least one reactive donor capable of providing two or more nucleophilic carbanions;
at least one reactive acceptor comprising two or more carbon-carbon double bond groups; and
at least one catalyst for catalyzing the Michael addition crosslinking reaction of said at least one reactive donor and said at least one reactive acceptor,
wherein the at least one reactive donor comprises at least one epoxy resin based reactive donor derived from at least one epoxy resin, and
wherein the at least one epoxy-based reactive donor comprises at least one first-C (O) -CH 2 -C (O) -fragment and at least one second-C (O) -CH 2 -C (O) -fragments, wherein the at least one first-C (O) -CH 2 -C (O) -fragments are covalently bonded into at least one epoxy resin backbone, and the at least one second-C (O) -CH 2 -a C (O) -fragment is covalently bonded to a lateral end of the at least one epoxy backbone.
2. The michael addition curable composition of claim 1, wherein the at least one first-C (O) -CH covalently bonded into the at least one epoxy resin backbone 2 -C (O) -fragments and said at least one second-C (O) -CH covalently bonded to the lateral end of said at least one epoxy resin backbone 2 -molar ratio of C (O) -fragments less than 1:1, and greater than 1:4, preferably at 1:1.5-2.5, more preferably 1: 1.8-2.2.
3. The michael addition curable composition of any one of claims 1-2, wherein the at least one first-C (O) -CH covalently bonded into the at least one epoxy resin backbone 2 The C (O) -fragment is derived from malonic acid.
4. The michael addition curable composition of any one of claims 1-3, wherein the at least one second-C (O) -CH covalently bonded to a lateral end of the at least one epoxy backbone 2 the-C (O) -fragment is derived from alkyl acetoacetates.
5. The michael addition curable composition of any one of claims 1-4, wherein the at least one epoxy resin backbone comprises at least one aromatic epoxy backbone.
6. The michael addition curable composition of any one of claims 1-5, wherein the at least one epoxy resin backbone comprises at least one ether oxygen bond (-O-).
7. The michael addition curable composition of any one of claims 1-6, wherein the at least one epoxy resin comprises bisphenol a epoxy resin, bisphenol F epoxy resin, phenolic epoxy resin, or a combination thereof.
8. The michael addition curable composition of any one of claims 1-7, wherein the at least one epoxy-based reactive donor is obtained by a process comprising the steps of:
(i) Subjecting at least one epoxy resin to a ring opening reaction with malonic acid in the presence of at least one catalyst at a temperature below 130 ℃ until the acid value approaches 0mgKOH/g, thereby introducing secondary hydroxyl groups in the at least one epoxy resin to form a reaction product; and is also provided with
(ii) Transesterification of the reaction product obtained in step i) with at least one alkyl acetoacetate to form at least one epoxide resin based reactive donor.
9. The michael addition curable composition of claim 8, wherein the at least one alkyl acetoacetate comprises at least one acetoacetateAcid C 1 -C 8 Alkyl esters.
10. The michael addition curable composition of any one of claims 1-9, wherein the at least one epoxy-based reactive donor has a polydispersity, as determined by GPC, in the range of 1.0 to 3.5, preferably in the range of 1.0 to 3.2, more preferably in the range of 1.1 to 3.0.
11. The michael addition curable composition of any one of claims 1-10, wherein the at least one epoxy-based reactive donor has a weight average molecular weight, as determined by GPC, in the range of 500g/mol to 15000g/mol, preferably in the range of 500g/mol to 10000g/mol, more preferably in the range of 500g/mol to 8000g/mol, still more preferably in the range of 500g/mol to 5000 g/mol.
12. The michael addition curable composition of any one of claims 1-11, wherein the at least one epoxy-based reactive donor has a glass transition temperature of 25 ℃ or higher, more preferably a glass transition temperature in the range of 25 ℃ to 40 ℃.
13. The michael addition curable composition of any one of claims 1-12, wherein the at least one reactive acceptor homo-polymerized formed polymer has a Tg of at least 100 ℃.
14. The michael addition curable composition of any one of claims 1-13, wherein the two or more carbon-carbon double bond groups have a structure represented by formula I:
-c=c-CX (formula I)
Wherein CX represents any one of aldehyde group (-CHO), ketone group (-CO-), ester group (-C (O) O-) and cyano group (-CN).
15. The michael addition curable composition of any one of claims 1-14, further comprising at least one solvent selected from one or more of isopropyl alcohol, propylene glycol methyl ether acetate, ethyl acetate, and butyl acetate.
16. The michael addition curable composition of any one of claims 1 to 15, used in the preparation of a coating, adhesive, sealant, foam, elastomer, film, molded article or ink.
17. A coating composition comprising the michael addition curable composition of any one of claims 1 to 16 as a film-forming resin.
18. The coating composition of claim 17, wherein the coating composition is applied at a wet coating thickness of 200 microns and dried for 1 day, the resulting cured coating having a chemical resistance of grade 4 or greater, as determined according to ASTM F2250-test method B.
19. The coating composition of claim 18, wherein, after mixing the components of the coating composition, the resulting mixture has a pot life of 4-24 hours.
20. A coated article comprising
A substrate having at least one major surface; and
a cured coating formed from the coating composition of any one of claims 17 to 19 directly or indirectly coated on at least a portion of the major surface.
21. The article of claim 20, wherein the substrate comprises wood, metal, plastic, ceramic, cement board, or any combination thereof.
22. A process for preparing a modified epoxy resin, the process comprising the steps of:
(i) Subjecting at least one epoxy resin to a ring opening reaction with malonic acid in the presence of at least one catalyst at a temperature below 130 ℃ until the acid value approaches 0mgKOH/g, thereby introducing secondary hydroxyl groups in the at least epoxy resin to form a reaction product; and is also provided with
(ii) Transesterification of the reaction obtained in step i) with alkyl acetoacetate to form said modified epoxy resin,
wherein the modified epoxy resin comprises at least one first-C (O) -CH 2 -C (O) -fragment and at least one second-C (O) -CH 2 -C (O) -fragments, wherein the at least one first-C (O) -CH 2 -C (O) -fragments are covalently bonded into at least one epoxy resin backbone, and the at least one second-C (O) -CH 2 -a C (O) -fragment is covalently bonded to a lateral end of the at least one epoxy backbone.
23. The method of claim 22, wherein the ring-opening reaction of the at least one epoxy resin with malonic acid is performed at a temperature of 90-120 ℃.
24. The method of claim 22, wherein the at least one catalyst is selected from quaternary ammonium salts, quaternary phosphonium salts, or combinations thereof, preferably comprising tetraalkylammonium bromide.
CN202211030044.XA 2022-08-25 2022-08-25 Michael addition curable composition and use thereof, and method for preparing modified epoxy resin suitable for the composition Pending CN117624830A (en)

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CN202211030044.XA CN117624830A (en) 2022-08-25 2022-08-25 Michael addition curable composition and use thereof, and method for preparing modified epoxy resin suitable for the composition
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EP2984133B1 (en) * 2013-04-08 2018-03-28 Allnex Netherlands B.V. Composition crosslinkable by real michael addition (rma) reaction
CA3099108A1 (en) * 2018-05-07 2019-11-14 Swimc Llc Corrosion-resistant primer and topcoat composition
CN110105799B (en) * 2019-05-07 2021-10-01 广东华润涂料有限公司 Coating composition for woodware and woodware made of the same

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