JP2003183348A - Curable compound and curable resin composition containing it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curable compound of high utility, of which a cured product is excellent in physical properties and can be decomposed safely (without generating a toxic gas in thermal decomposition) and easily, and a curable resin composition containing the compound. <P>SOLUTION: The curable compound has a Dields-Alder reaction addition part formed through Dields-Alder reaction from a conjugated diene structure and a dienophile structure, and a functional group selected from the group consisting of isocyanato groups, blocked isocyanate groups, alkoxysilyl groups and epoxy groups, that it can be cured by the functional group, and that the cured material can be decomposed (broken up) through dissociation of the Dields-Alder reaction addition part by heating the cured material formed through crosslinking of the functional group. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a curable compound and a curable resin composition containing the same. More specifically, it relates to a curable compound that is safe (does not generate a toxic gas upon thermal decomposition) and can be easily decomposed (disassembled), has excellent cured physical properties, and is highly practical, and a curable resin composition containing the same.

[0002]

2. Description of the Related Art In recent years, recyclability is required in various fields from the viewpoint of being environmentally friendly and reducing costs. Curable resins widely used in adhesives, sealants, waterproof materials, paints, foams, etc. (eg urethane resin, epoxy resin, silicone resin, etc.) can also be liquefied and cured while maintaining the original properties of those resins. If the above can be repeated, not only the resin can be recycled, but also the members once adhered to each other can be disassembled and the reinforcing material can be easily removed.

Urethane resins widely used for adhesives, sealants, etc. are useful because they are excellent in storage stability and can be moisture-cured with one liquid, but conventional curable urethane resins are polyether polyol type, It is produced by reacting a polyester polyol-based polymer polyol, a polymer polyol-based polyol, or the like with a polyisocyanate. These urethane bonds are relatively stable, and when heated above 200 ° C., toxic gases such as hydrocyanic acid are generated. While it is known to decompose. Therefore, conventionally, from the viewpoint of safety of dismantling work, workability, etc., disassembling of members that have been once adhered with the resin has been rarely performed.

Epoxy resins and silicone resins, which are widely used as adhesives and waterproof materials, are useful in that they are excellent in storage stability and weather resistance, but they are formed by the cleavage (curing) reaction of epoxy groups. It is known that a bond (for example, a 1-alkylamino-2-hydroxyethyl group or the like), a siloxane bond, or the like does not decompose unless the temperature is higher than 200 ° C. For this reason, conventionally, from the viewpoints of safety of disassembly work, workability, equipment investment, etc., disassembling of members once adhered with the resin has been rarely performed.

On the other hand, a saturated condensation resin having a furan skeleton in its side chain (eg polyester, polyurethane, polyamide, etc.) is crosslinked (Diels-Alder reaction) at 100 ° C. in the presence of bismaleimide, and decrosslinked at 140 ° C. (retro Diels-Alder reaction) (US Pat. No. 3,435,003). In this technique, a functional group of a saturated condensation resin and a compound having a furan structure are completely reacted (100 mol%) to introduce the compound having the furan structure into a basic skeleton, and the compound having the furan structure and a maleimide. The present invention relates to a thermoreversible polymer that adjusts the reaction rate with a compound having a structure. In particular, the isocyanate group of the urethane prepolymer and a compound having a furan structure are completely (100 mol%) reacted and introduced, and 10 to 100% of the compound having a furan structure is reacted with a compound having a maleimide structure. The curing reaction of the prepolymer is all based on the Diels-Alder reaction, and the crosslinking by the reaction is 10%.
As described above, the cross-linking strength of the whole resin is weak and the dissociation temperature is extremely low, which is not practical.

[0006]

The present invention introduces a Diels-Alder reaction addition portion formed by the Diels-Alder reaction, so that decomposition (disassembly) after curing by the functional group such as an isocyanate group is safe (heating). A first object of the present invention is to provide a curable compound and a curable resin composition containing the curable compound, which does not generate a toxic gas upon decomposition and can be easily produced. Further, by introducing the Diels-Alder reaction addition portion in a specific ratio, a curable compound having a high cross-linking strength of the cured product and a low decomposition temperature (excellent in cured physical properties), and a highly practical curable compound and curing containing the same A second object is to provide a water-soluble resin composition. Further, it is a third object to provide a curable compound having physical properties (performance) according to applications and the like and a curable resin composition containing the same by adjusting the introduction ratio of the Diels-Alder reaction addition part. To do.

[0007]

Means for Solving the Problems As a result of extensive studies on a curable compound capable of safely and easily decomposing (disassembling) after curing, the present inventor found that a Diels-Alder reaction addition portion formed by a Diels-Alder reaction was formed. Introducing a curable compound that can be safely and easily decomposed (disassembled) by the above-mentioned functional groups such as isocyanate groups after curing by introduction, has high practicability, and can obtain physical properties (performance) according to applications etc. The invention was completed.

That is, 1) the present invention is selected from the group consisting of a Diels-Alder reaction addition portion formed by a Diels-Alder reaction from a conjugated diene structure and a dienophile structure, and an isocyanate group, a blocked isocyanate group, an alkoxysilyl group and an epoxy group. And a functional group capable of being cured by the functional group, and heating the cured product in which the functional group undergoes a crosslinking reaction,
There is provided a curable compound characterized in that the Diels-Alder reaction addition part is dissociated and the cured product can be decomposed (disassembled). Thereby, the first and second objects of the present invention can be achieved.

Here, the "curable compound" may be a low molecular compound or a high molecular compound (prepolymer etc.), and the "Diels-Alder reaction addition part" is introduced into any of the skeletons of these compounds (hereinafter , Low molecular weight compounds and high molecular weight compounds into which the Diels-Alder reaction addition part is introduced are referred to as "basic compounds." For example, when the base compound is a prepolymer, it can be introduced into its main chain or side chain. The "Diels-Alder reaction addition part" is a site having a ring structure formed by a Diels-Alder reaction of a conjugated diene structure and a dienophile structure, and is unsolved at a temperature at which a crosslink is formed by the functional group such as an isocyanate group. Not separated, or even if it dissociates, the Diels-Alder reaction addition structure does not participate in the curing reaction and is formed again after the temperature decreases, and the temperature is higher than the temperature at which cross-linking is formed by the functional group and the binding site formed by the functional group, Alternatively, it refers to a portion in which the basic skeleton of the basic compound into which the Diels-Alder reaction addition portion is introduced is thermally dissociated at a temperature lower than the decomposition or dissociation temperature. Further, in the present invention, the “thermally dissociable site” refers to a site having at least one Diels-Alder reaction addition part (ring structure) (see FIGS. 1 and 2). The reversible thermal dissociation of the present invention is generally caused by the Diels-Alder addition reaction, which is a thermoreversible equilibrium reaction, at a low temperature and the reverse Diels-Alder reaction at a high temperature. It does not mean thermal dissociation by the functional group such as the isocyanate group. In the present invention, by utilizing such Diels-Alder reaction and retro Diels-Alder reaction, cross-linking by the Diels-Alder reaction addition part (construction of ring structure) and de-crosslinking by Diels-Alder reaction addition part (dissociation of ring structure) ) Is reversibly repeated to achieve hardening and softening or fluidization of the curable compound.

The following three modes are mentioned as preferred modes of the present invention. The Diels-Alder reaction addition part is the basic compound (low molecular compound, high molecular compound (prepolymer, etc.))
And a dienophile structure of a polydienophile compound.
Here, if at least one conjugated diene structure and at least two dienophile structures are present, different curable compounds can mutually undergo a three-dimensional crosslinking reaction by the Diels-Alder reaction addition section. The Diels-Alder reaction addition part is a curable compound comprising a dienophile structure introduced into the basic compound; and a conjugated diene structure of a polyconjugated diene compound.
Here, if at least two conjugated diene structures and at least one dienophile structure are present, different curable compounds can mutually undergo a three-dimensional crosslinking reaction by the Diels-Alder reaction addition section. The Diels-Alder reaction addition part is a curable compound comprising a conjugated diene structure introduced into the basic compound; and a dienophile structure introduced into the basic compound. Here, if at least one conjugated diene structure and at least one dienophile structure are present, different curable compounds can mutually undergo a three-dimensional crosslinking reaction by the Diels-Alder reaction addition section.

Further, it is preferable that the conjugated diene structure is a furan skeleton or the dienophile structure is a maleimide skeleton, and a curable compound in which the conjugated diene structure is a furan skeleton and the dienophile structure is a maleimide skeleton is particularly preferable. Is one of.

Further, the present invention is preferably a curable compound obtained by reacting a part of the functional group with the Diels-Alder reaction addition part. Thereby, the first to third objects of the present invention can be achieved.

Further, 2) the present invention provides a curable resin composition containing the curable compound described in 1). Thereby, the first to third objects of the present invention can be achieved.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below. The present invention has a Diels-Alder reaction addition part formed by a Diels-Alder reaction from a conjugated diene structure and a dienophile structure, and a functional group selected from the group consisting of an isocyanate group, a blocked isocyanate group, an alkoxysilyl group and an epoxy group. Curing, wherein the functional group can be cured, and the Diels-Alder reaction addition part is dissociated to decompose (disassemble) the cured product by heating the cured product in which the functional group is cross-linked. It is a sex compound.

In the present invention, the cured product can be decomposed (disassembled) by decrosslinking (dissociation of the ring structure) using the Retro Diels Alder reaction. Also, having a functional group such as an isocyanate group in the molecule enables curing in the presence of moisture or a curing agent.

The curable compound of the present invention can be crosslinked by a Diels-Alder reaction between a conjugated diene structure and a dienophile structure to form a thermally dissociable site, in addition to crosslinking by a functional group such as an isocyanate group. That is, the following modes are mentioned as an example of the curable compound of the present invention. 1) A Diels-Alder reaction addition part is a curable compound consisting of a conjugated diene structure introduced into a basic compound; and a dienophile structure of a polydienophile compound. 2) A Diels-Alder reaction addition part is a curable compound comprising a dienophile structure introduced into a basic compound; and a conjugated diene structure of a polyconjugated diene compound. 3) A Diels-Alder reaction addition part is a curable compound consisting of a conjugated diene structure introduced into a basic compound; and a dienophile structure introduced into a basic compound. here,
The conjugated diene structure and the dienophile structure may be introduced into the same basic compound or different basic compounds.

First, the Diels-Alder reaction addition section will be described. The "Diels-Alder reaction addition part" of the present invention is a site having a ring structure formed by a Diels-Alder reaction of a conjugated diene structure and a dienophile structure, and is a temperature at which a cross-link is formed by a functional group such as an isocyanate group. Does not dissociate, or does not participate in the curing reaction even if dissociated, and after the temperature decreases, the Diels-Alder reaction adduct structure is formed again, and the temperature is higher than the temperature at which crosslink is formed by the functional group and the bond formed by the functional group. A site or a part in which the basic skeleton of the basic compound into which the Diels-Alder reaction addition part is introduced is thermally dissociated at a temperature lower than the decomposition or dissociation temperature.

The conjugated diene structure forming such a Diels-Alder reaction addition portion is not particularly limited, and a chain conjugated diene structure and a cyclic conjugated diene structure can be used, but since it has excellent stability against heat and the like, Cyclic conjugated diene structures are preferred. The conjugated diene structures used in the present invention are listed in Table 1.

[0019]

[Table 1]

(In Table 1, R ^{1 to} R ⁶ are independently of each other a group selected from the group consisting of a hydrogen atom, a hydrocarbon group and a lower alkoxyl group, and may be the same or different. Here, the hydrocarbon group is a lower (C1-6) alkyl group or an aromatic hydrocarbon group, and specifically, as the lower alkyl group, a methyl group, an ethyl group, a propyl group, or a butyl group is used. , A pentyl group and a hexyl group, and an aromatic hydrocarbon group includes a phenyl group which may be substituted with a lower alkyl group or a lower alkoxyl group. As the lower alkoxyl group, a methoxy group, an ethoxy group,
Examples include propoxy group, butoxy group, pentyloxy group and hexyloxy group. The lower alkyl group and the lower alkoxyl group having 3 or more carbon atoms include each isomer (eg, isopropyl group). Among the above-mentioned conjugated diene structures, those having a hetero atom, particularly those having a furan skeleton described later can be preferably used.

The dienophile structure forming the Diels-Alder reaction addition portion of the present invention is an unsaturated compound which reacts additionally with the conjugated diene structure to give a cyclic compound. The dienophile structure used in the present invention is not particularly limited. Second, the dienophile structure used in the present invention
List in the table.

[0022]

[Table 2]

The present invention is a curable compound in which a Diels-Alder reaction addition portion formed from the conjugated diene structure and the dienophile structure by a Diels-Alder reaction is introduced into a basic compound. The following three modes 1) to 3) are provided. Is mentioned. In the first aspect, the Diels-Alder reaction addition part comprises a conjugated diene structure introduced into a basic compound; and a dienophile structure of a polydienophile compound.
That is, by introducing the conjugated diene structure into the basic compound,
It is a curable compound obtained by reacting with a polydienophile compound having two or more dienophile structures. Here, if at least one conjugated diene structure and at least two dienophile structures are present, different curable compounds can mutually undergo a three-dimensional cross-linking reaction by the Diels-Alder reaction addition portion, and the cured isocyanate group can be cured. Objects can be disassembled (disassembled).

In the second embodiment, the Diels-Alder reaction addition part comprises a dienophile structure introduced into a basic compound; and a conjugated diene structure of a polyconjugated diene compound. That is, by introducing the above dienophile structure into the basic compound,
It is a curable compound obtained by reacting with the conjugated diene compound having the above conjugated diene structure. Here, if at least two conjugated diene structures and at least one dienophile structure are present, different curable compounds can mutually undergo a three-dimensional cross-linking reaction by the Diels-Alder reaction addition part, and the cured isocyanate groups can be cured. Objects can be disassembled (disassembled).

In the third aspect, the Diels-Alder reaction addition part comprises a conjugated diene structure introduced into the basic compound; and a dienophile structure introduced into the basic compound. Here, even if the conjugated diene structure and the dienophile structure are introduced into the same basic compound (curable compound having both structures), different basic compounds (curable compound having conjugated diene structure and curable compound having dienophile structure) (Mixture with). Also, at least one conjugated diene structure and at least one dienophile structure
If so, different curable compounds can mutually undergo a three-dimensional cross-linking reaction by the Diels-Alder reaction addition section, and a cured product in which an isocyanate group or the like has been cured can be decomposed (disassembled).

[0026] The Diels-Alder reaction addition portion may substantially have at least A in the molecule. If the Diels-Alder reaction-added portion has A units, the Diels-Alder reaction-added portion can be decrosslinked and dissociated by heating the cured product. Here, “substantially at least A in the molecule” means that m Diels-Alder reaction addition moieties contained in one thermolabile site shared by n curable compound molecules are shared between each molecule. Value evenly distributed (m /
It means that the sum of n) is A or more. Specifically, referring to FIG. 1 (first embodiment), the curable compound of the present invention forms a dimer (n = 2) by one heat dissociable site. Since the thermolabile site of the dimer contains two Diels-Alder reaction addition parts (m = 2), m / n is 1 when considering one molecule according to the above definition, and one Diels in one molecule. It will have an alder reaction addition part. Further, referring to FIG. 2 (third aspect described above), the curable compound of the present invention forms a dimer (n = 2) by one heat dissociable site. The 2
The thermal dissociation site of the monomer contains one Diels-Alder reaction addition part (m = 1). Therefore, considering one molecule, m / n becomes 1/2 and half in one molecule. Will have a Diels-Alder reaction addition part. In addition, in FIG. 2, B is a divalent organic group which may contain a hetero atom.

In the present invention, the value of A depends on the introduction amount of the Diels-Alder reaction addition portion (blocking rate described later, etc.), but it is necessary that it is substantially 1/3 or more in the molecule. Yes, preferably 1/2 or more, more preferably 1 or more. When it is 1/3 or more, different curable compounds can be three-dimensionally cross-linked with each other, and can be easily decomposed (disassembled) after curing with an isocyanate group or the like.

The Diels-Alder reaction addition section of the present invention utilizes the fact that the Diels-Alder reaction is a thermoreversible equilibrium reaction, and specifically, the Diels-Alder reaction and the retro Diels-Alder reaction are used to crosslink. The reaction (construction of the Diels-Alder reaction addition part (ring structure)) and the decrosslinking reaction (dissociation of the Diels-Alder reaction addition part (ring structure)) can be repeated. In addition, the Diels-Alder reaction addition part does not dissociate at the temperature at which crosslinking is formed by a functional group such as an isocyanate group, or does not participate in the curing reaction even if dissociated, and the Diels-Alder reaction addition structure is formed again after the temperature decreases. , Thermal dissociation at a temperature higher than the temperature at which crosslinks are formed by the functional group and the binding site formed by the functional groups, or the basic skeleton of the basic compound into which the Diels-Alder reaction addition part is introduced is lower than the decomposition or dissociation temperature. It has the property.

Therefore, the Diels-Alder reaction and the retro Diels are appropriately selected by appropriately selecting the conjugated diene structure (including a compound having a conjugated diene structure. The same applies hereinafter) and the dienophile structure (including a compound having a dienophile structure. The same applies hereinafter). By setting the energy amount of the Alder reaction within a specific range, it is possible to construct a safe curable compound that does not generate poisonous gas during thermal dissociation.

Next, the thermally dissociable site will be described. In the present invention, the “thermal dissociable site” refers to a site shared by a plurality of molecules having at least one Diels-Alder reaction addition part obtained by the reaction between the conjugated diene structure and the dienophile structure described above. As a result, a strong cross-linking structure derived from a functional group such as isocyanate (hereinafter sometimes referred to as "permanent cross-linking") and a thermally dissociative cross-linking structure different from this are formed, so that the cross-linking strength is strong and the decomposition is high. A curable compound having a low temperature (excellent cured properties) and high practicality can be obtained. The Diels-Alder reaction addition portion and the heat dissociable portion may be introduced at any position of the skeleton of the basic compound. For example, in the case of a high molecular compound (prepolymer etc.), it may be introduced in the main chain of the polymer. Or may be introduced into the side chain. From the viewpoint of ease of introduction, physical properties of a cured product, and thermal dissociation property, it is preferably at the terminal of the main chain.

The curable compound of the present invention has, in the molecule, a functional group selected from the group consisting of an isocyanate group, a blocked isocyanate group, an alkoxysilyl group and an epoxy group, as well as a thermally dissociable site containing a Diels-Alder reaction addition part. Have at least one. These groups are preferably at the ends of the molecule. At least one of these functional groups
By having one, a curing reaction (permanent crosslinking) becomes possible. When two or more of these groups are contained, they may be the same or different.

Here, the blocked isocyanate group means
Isocyanate group is blocked by a protective group, for example, a group that can be easily removed by heat or moisture to generate an isocyanate group, for example, blocking agents such as alcohols, phenols, oximes, triazoles, caprolactams, etc. An isocyanate group blocked with is preferably mentioned.

Preferred examples of alcohols include methanol, ethanol, propanol, hexanol, lauryl alcohol, t-butanol, cyclohexanol and the like. Preferred examples of phenols include xylenol, naphthol, 4-methyl-
2,6-di-t-butylphenol and the like can be mentioned. Preferred examples of oximes include 2,6-dimethyl-4-heptanone oxime, methyl ethyl ketoxime, 2-heptanone oxime and the like. In addition, 3,5-dimethylpyrazole, 1,2,4-triazole and the like can be preferably used. Of these, methanol and xylenol are preferable as the blocking agent.

The curable compound of the present invention is not particularly limited as long as it is a low molecular weight compound having these groups, a thermosetting resin or a moisture curable resin or a prepolymer of these, and the physical properties of the cured product (adhesive strength, etc.). ) And from the viewpoint of handleability, urethane prepolymers, epoxy resins, silane compounds and modified polymers thereof are preferable. Further, the number average molecular weight of the polymer compound is not particularly limited, but it is preferably liquid at room temperature from the viewpoint of handleability and the like. Furthermore, such low molecular weight compounds and resins are
It is also possible to use one kind or a mixture of two or more kinds.

As the urethane prepolymer, a commonly used prepolymer can be used, and examples of the polyol used for producing the prepolymer include polyether polyol, polyester polyol, other polyols and mixed polyols thereof. Examples of the polyether polyol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, 4,4′-dihydroxyphenylpropane, 4,
Dihydric alcohols such as 4'-dihydroxyphenylmethane; polyhydric alcohols such as glycerin, 1,1,1-trimethylolpropane, 1,2,5-hexanetriol and pentaerythritol; diamines such as ethylenediamine and aromatic diamines. A polyol obtained by adding one or more saccharides such as sorbitol and one or two or more alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, and styrene oxide. .

As the polyester polyol, one or two kinds of ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, cyclohexanedimethanol, glycerin, 1,1,1-trimethylolpropane and other low molecular weight polyols are used. Above, glutaric acid, adipic acid, pimelic acid,
Examples thereof include condensation polymers of suberic acid, sebacic acid, terephthalic acid, isophthalic acid and one or more low molecular carboxylic acids and oligomeric acids; ring-opening polymers such as propionlactone, valerolactone and caprolactone.

Other polyols include polymer polyols, polycarbonate polyols, polybutadiene polyols, hydrogenated polybutadiene polyols, acrylic polyols and ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butanediol, pentanediol,
Examples thereof include low molecular weight polyols such as hexanediol.

The polyisocyanate compound is not particularly limited as long as it is a compound having two or more isocyanate groups, and specifically, 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tridiene. Diisocyanate (2,6-TDI), 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI),
Aromatic polyisocyanates such as p-phenylene diisocyanate, polymethylene polyphenylene polyisocyanate, xylylene diisocyanate (XDI) and 1,5-naphthalene diisocyanate; aliphatic such as hexamethylene diisocyanate (HDI) and norbornane diisocyanatomethyl (NBDI) Polyisocyanate; isophorone diisocyanate (IPDI), H ₆ XDI
Alicyclic polyisocyanates such as (hydrogenated XDI) and H ₁₂ MDI (hydrogenated MDI); carbodiimide-modified polyisocyanates of the above polyisocyanates, or isocyanurate-modified polyisocyanates thereof. It is also possible to use an isocyanate compound having at least one isocyanate group having a large steric hindrance. Specifically, preferred examples include TMI (monoisocyanate compound), TMXDI (diisocyanate compound), and secene (triisocyanate compound) manufactured by Mitsui Cytec. These may be used alone or in combination of two or more.

Of these, urethane prepolymers obtained from polypropylene glycol and TDI and / or MDI are preferable because they are easily available and the properties (performance) of the cured product are well balanced.

In producing the urethane prepolymer, the raw material amount ratio is the equivalent ratio of the isocyanate group of the polyisocyanate compound to the hydroxyl group of the polyol (NCO).
/ OH ratio) is 1.4 to 3.0, and it is preferable to set the amount ratio to 1.7 to 2.5. Within this range, the physical properties of the cured product will be good without foaming due to the remaining polyisocyanate compound and without increasing the viscosity of the urethane prepolymer due to molecular chain extension.

The production conditions of the urethane prepolymer are not particularly limited, and the usual production conditions of the urethane prepolymer can be mentioned. That is, the reaction temperature is 50 to 10
The reaction can be carried out under atmospheric pressure at about 0 ° C. Further, a urethane-forming catalyst such as an organic tin compound or an organic bismuth compound can also be used.

As the prepolymer having a blocked isocyanate group, a urethane prepolymer in which the isocyanate group is protected by the above blocking agent or the like can be used. In the present invention, the blocking rate is not particularly limited, and all the isocyanate groups may be protected or a part of the isocyanate groups may be protected depending on the use, the physical properties of the cured product and the like. The reaction conditions for blocking are not particularly limited, and the conditions for synthesizing the urethane prepolymer can be used.

The epoxy resin is not particularly limited, and specifically, an epoxy resin can be used. For example, bisphenol A, bisphenol F, bisphenol S, hexahydrobisphenol A, tetramethylbisphenol A, pyrocatechol, resorcinol, cresol novolac, tetrabromobisphenol A, trihydroxybiphenyl, bisresorcinol, bisphenol hexafluoroacetone, tetramethylbisphenol G, glycidyl ether type obtained by reaction of polyphenols such as F and bixylenol with epichlorohydrin; aliphatic such as glycerin, neopentyl glycol, ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, polyethylene glycol, polypropylene glycol Polyglycidyl obtained by reaction of polyhydric alcohols with epichlorohydrin Ether type; p-oxybenzoate, beta-glycidyl ether ester type obtained by reacting hydroxycarboxylic acid with epichlorohydrin, such as oxy-naphthoic acid; phthalic acid, methyl phthalic acid, isophthalic acid,
Terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, endomethylenetetrahydrophthalic acid,
Endomethylene hexahydrophthalic acid, trimellitic acid, polyglycidyl ester type derived from polycarboxylic acid such as polymerized fatty acid; glycidyl aminoglycidyl ether type derived from aminophenol, aminoalkylphenol, etc .; derived from aminobenzoic acid Glycidylaminoglycidyl ester type; aniline, toluidine, tribromoaniline, xylylenediamine, diaminocyclohexane, bisaminomethylcyclohexane, 4,4'-diaminodiphenylmethane, 4,4'-
Glycidyl amine type derived from diaminodiphenyl sulfone; further epoxidized polyolefin, glycidyl hydantoin, glycidyl alkyl hydantoin,
Triglycidyl cyanurate and the like; butyl glycidyl ether, phenyl glycidyl ether, alkylphenyl glycidyl ether, benzoic acid glycidyl ester, monoepoxy compounds such as styrene oxide, and the like, and one or a mixture of two or more thereof may be used. it can. In this case, the mixing ratio can be any mixing ratio depending on the use, storage stability, low temperature storability and physical properties of the cured product.

Of these, an epoxy resin obtained by partially reacting bisphenol A glycidyl ether with furfurylamine, furfuryl alcohol, phenol maleimide or aniline maleimide is preferable. The production conditions of the prepolymer are not particularly limited, and the prepolymer can be produced under the conditions usually used. For example, it can be produced by stirring at a temperature of 120 ° C. or lower and normal pressure.

The silane compound is not particularly limited, and specifically, for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, β -(3,4 epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane and other epoxy group-containing silane compounds; γ-isocyanatopropyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, γ-isocyanate Propylmethyldiethoxysilane, γ-isocyanate propylmethyldimethoxysilane, γ-isocyanateethyltrimethoxysilane, γ-isocyanateethyltriethoxysilane, γ-isocyanateethylmethyldiethoxysilane, γ-a Isocyanate group-containing silane compounds such as cyanate ethylmethyldimethoxysilane; γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-ureidopropyl Trimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, N Amino group-containing silane compounds such as -phenyl-γ-aminopropyltrimethoxysilane; γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-me Mercapto group-containing silane compounds such as captopropylmethyldiethoxysilane; β-carboxyethyltriethoxysilane, β-carboxyethylphenylbis (2-methoxyethoxy) silane, N-β- (carboxymethyl) aminoethyl-γ-amino Carboxysilane compounds such as propyltrimethoxysilane; vinyl group-containing silane compounds such as vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (βmethoxyethoxy) silane; γ-methacryloxypropylmethyldimethoxysilane, γ- Methacryloxy group-containing silane compounds such as methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane; γ-chloropropyl Reaction products and prepolymers of one or more kinds of halogen-containing silane compounds such as trimethoxysilane and one or more kinds of furfuryl alcohol, furfuryl amine and the like; The production can be carried out under the reaction conditions and methods usually used.

The modified polymer is not particularly limited, and examples thereof include alkoxysilyl group-modified (block) urethane prepolymer, epoxy-modified (block) urethane prepolymer, isocyanate-modified epoxy prepolymer, alkoxysilyl group-modified epoxy prepolymer, and isocyanate-modified. Examples thereof include silane compounds and alkoxysilyl group-modified silane compounds.

The alkoxysilyl group-modified (block) urethane prepolymer and the epoxy-modified (block) urethane prepolymer can be prepared by using, for example, an alkoxysilyl group-containing polyol, an epoxy group-containing polyol or the like as a raw material for the urethane prepolymer. It can be manufactured under the conditions
It can also be produced by grafting a urethane prepolymer with a compound having these groups. Further, an isocyanate-modified epoxy prepolymer, an alkoxysilyl group-modified epoxy prepolymer, an isocyanate-modified silane compound and an alkoxysilyl group-modified silane compound can be similarly produced.

The curable compound of the present invention contains, in the molecule, a functional group selected from the group consisting of an isocyanate group, a blocked isocyanate group, an alkoxysilyl group and an epoxy group, in addition to the thermally dissociable site containing the Diels-Alder reaction addition part. Which has at least one group selected from the group consisting of an acid anhydride group, an amino group, a latent amino group, a mercapto group and a carboxyl group in the molecule in addition to these functional groups. You can also If it further has a group capable of reacting with an isocyanate group or the like to crosslink, the crosslink density is improved and the physical properties of the cured product are excellent.

Here, the latent amino group means a group in which the amino group is blocked by a protective group and can be easily removed by, for example, moisture or heat to generate an amino group. For example, an aliphatic polyamine and a ketone are used. Reaction product ketimine; n
-Hexylamine, monoethylamine, benzylamine, diethylamine, piperidine, triethylamine,
Boron trifluoride-amine complex, which is a compound of an amine such as aniline and boron trifluoride; dicyandiamide or o-tolyl biguanide, α-2,5-dimethyl biguanide, α, ω-diphenyl biguanide, 5-hydroxynaphthyl- Derivatives of dicyandiamide such as 1-biguanide; succinic acid hydrazide, adipic acid hydrazide, isophthalic acid hydrazide, p-oxybenzoic acid hydrazide,
Acid hydrazides such as salicylic acid hydrazide and phenylaminopropionic acid hydrazide; diaminomaleonitrile or derivatives thereof; melamine derivatives such as diallyl melamine; amine imides synthesized by carboxylic acid ester, dimethylhydrazine and epoxy compound; ethylenediamine, hexamethylenediamine, Salts of diamines such as piperidine with dicarboxylic acids such as benzoic acid, phthalic acid, adipic acid, sebacic acid, 2,4,4-trimethyl-2,
Polyamines such as 4,7-trihydroxyflavan and N,
Salts of polyhydroxyphenols such as N′-dimethyl 1,3-propanediamine, phenylphosphonates of polyamines, phenylphosphates of polyamines; ester compounds of sulfonic acid and primary alcohol, monoesters of phosphoric acid or Examples thereof include a diester or a mixture thereof, and an ester compound obtained by an addition reaction between a sulfonic acid and an epoxy compound. Further, an ultraviolet curing agent such as an aromatic diazonium salt or an aromatic sulfonium salt may also be used.

In the curable compound of the present invention, a functional group selected from the group consisting of an isocyanate group, a blocked isocyanate group, an alkoxysilyl group and an epoxy group and a Diels-Alder reaction addition part are introduced into a basic compound separately and independently. However, it is preferable to introduce a part of the functional group such as an isocyanate group by reacting with the Diels-Alder reaction addition section. In this case, a functional group such as an isocyanate group is first introduced, and 20 to 80 mol% thereof (having an acid anhydride group, a hydroxyl group, an amino group, a latent amino group, a mercapto group, a carboxyl group and the like in the molecule) In the case of based on the amount of functional groups including the content of these groups),
Diels Alder reaction addition part (including compounds having conjugated diene structure and compounds having dienophile structure)
It is preferably obtained by reacting with a substituent capable of reacting with a functional group and blocking.

The blocking rate can be adjusted to an arbitrary ratio in order to satisfy the physical properties (performance) depending on the application etc., but is preferably 30 to
It is 70 mol%, particularly preferably 40 to 60 mol%.
Here, the blocking rate is 20 to 80 mol% of the functional group means that the total amount of the functional groups contained in the molecule (the acid anhydride group, the hydroxyl group, the amino group, the latent amino group, the mercapto group and the carboxyl group described above in the molecule). In the case of having a group and the like), the Diels-Alder reaction addition part is introduced by reacting 20 to 80 mol with the substituent when the content of these groups is 100 mol. Within this range, the Diels-Alder reaction addition section forms crosslinks (permanent crosslinks) due to functional groups that are not blocked, so the crosslink strength of the cured product is strong, and the heat-dissociable site easily dissociates. It is a highly practical curable compound having a low decomposition temperature and having both cross-linking strength and low temperature decomposability.

At least one blockage is contained in the functional group and the Diels-Alder reaction addition part (including a compound having a conjugated diene structure and a compound having a dienophile structure).
It can be carried out by reaction with a group having two active hydrogens. For example, the isocyanate group can be blocked by an addition reaction, the alkoxysilyl group by a dealcoholization reaction, the epoxy group by an epoxy cleavage reaction (addition reaction), etc. The blocking conditions in these cases can be carried out under commonly used conditions. .

Crosslinking and decrosslinking (thermal dissociation) reactions of the curable compound of the present invention will be described with reference to FIGS.
Fig. 1 is a urethane prepolymer having one heat-dissociable site in the molecule (substantially one Diels-Alder reaction addition site in the molecule) and three isocyanate groups. Fig. 2 shows the heat-dissociable site in the molecule. 1 (the Diels-Alder reaction addition part is substantially 1/2 in the molecule) and 3 isocyanate groups
It is the figure which showed the urethane prepolymer which has one piece. Figure 3
FIG. 2 is a diagram showing a cured state and a dissociated state of the prepolymer having substantially one Diels-Alder reaction addition portion in the molecule shown in FIG. 1. The prepolymer shown in FIG. 1, which has substantially one Diels-Alder reaction addition portion in its molecule, is moisture-cured (permanently cross-linked) by three isocyanate groups to become a urethane polymer in a cured state shown in FIG. . The conjugated diene structure is shown with a furan skeleton and the dienophile structure is shown with a maleimide skeleton.

The urethane polymer in the cured state is from 120 to
When heated to 200 ° C., the two Diels-Alder reaction addition sites of the heat-dissociable site undergo a retro-Diels-Alder reaction and dissociate into a compound having a conjugated diene structure (furan skeleton) and a dienophile structure (maleimide skeleton) (see FIG. 3). Dissociated state). That is, the sites crosslinked by urethane bonds (permanent crosslinks, bonds shown by “●” in FIG. 3) are not dissociated, but the thermally dissociable sites that were independently crosslinked are decrosslinked by heating and easily Can be disassembled (disassembled). The permanent crosslinking can be cured under ordinary conditions in the presence of moisture or a curing agent.

The applicant has an elastomer having a Diels-Alder reaction addition portion, capable of reversibly causing the formation and collapse of a crosslinked structure by a temperature change, having excellent heat resistance, low cold flow property, and easy recycling. The technology related to this is reported (Japanese Patent Laid-Open No. 2000-1529). However, while the technique is a technique capable of reversibly solidifying and fluidizing by introducing a Diels-Alder reaction addition part into a high-molecular weight elastomer, the present invention uses an addition part by the Diels-Alder reaction and an isocyanate group or the like. This is a technique in which a compound or oligomer having a cross-linking portion is provided, cross-linking is performed at the cross-linking portion, and thermal dissociation is performed at the Diels-Alder reaction addition portion. That is, the present invention is one in which the curable compound itself of the present invention is cured and thermally dissociated by curing with a functional group other than the Diels-Alder reaction addition portion and thermally dissociating in the Diels-Alder reaction addition portion.

The production of the curable compound of the present invention is carried out according to the first method described above.
Although it depends on the aspects to the third aspect, first, the known method described above, etc., using a compound having at least one functional group selected from the group consisting of an isocyanate group, a blocked isocyanate group, an alkoxysilyl group and an epoxy group in the molecule. Manufactured by. Next, a conjugated diene structure and / or a dienophile structure is introduced into the base compound. As the method, 1) the conditions in which a compound having a conjugated diene structure and a compound having a dienophile structure are used in a usual Diels-Alder reaction (for example, under normal pressure, room temperature to 12).
A method of reacting the thermally dissociable site that has been subjected to an addition reaction at 0 ° C.) with the basic compound, 2) reacting the basic compound with a compound having a conjugated diene structure, and then a compound having a dienophile structure is usually used. Of the Diels-Alder reaction of 3), 3) reacting the basic compound with a compound having a dienophile structure, and then reacting a compound having a conjugated diene structure under the conditions used in a usual Diels-Alder reaction. Methods and the like. It is also possible to introduce a conjugated diene structure and a dienophile structure in the same molecule by these methods.

Specifically, the curable compound of the first aspect is
A basic compound having a functional group such as an isocyanate group is produced by the above method, then a conjugated diene structure is introduced into the basic compound, and a compound having a dienophile structure is reacted with the conjugated diene-modified basic compound by a Diels-Alder reaction. can get. The curable compound of the second aspect is produced by preparing a basic compound having a functional group such as an isocyanate group by the above method, then introducing a dienophile structure into the basic compound, and modifying the compound having a conjugated diene structure with the dienophile. Obtained by Diels-Alder reaction with the basic compound. The curable compound of the third aspect produces a basic compound having a functional group such as an isocyanate group by the above method,
Then, a conjugated diene structure is introduced into one of the basic compounds, a dienophile structure is introduced into the other of the basic compounds, and both basic compounds are subjected to a Diels-Alder reaction. Alternatively, a basic compound having a functional group may be produced, and then a conjugated diene structure and a dienophile structure may be introduced into the same basic compound to cause Diels-Alder reaction between different basic compounds. The above-mentioned reaction conditions may be those usually used.

The curable compound of the present invention is safely decomposed (disassembled) after curing by a functional group such as an isocyanate group by introducing a thermally dissociable site formed by the Diels-Alder reaction into its basic skeleton. It is a highly practical curable compound that does not generate a toxic gas during thermal decomposition) and can be easily produced, and has a high cross-linking strength and a low decomposition temperature.

In the present invention, a curable compound having a Diels-Alder reaction addition portion is used, but if necessary, for example, a composition of a basic compound having a conjugated diene structure and a polydienophile compound in the first embodiment. May be Similarly, it can be used as a composition in the second and third aspects.

The curable compound containing the Diels-Alder reaction addition portion formed from the conjugated diene structure and the dienophile structure by the Diels-Alder reaction has been described. Is one of the particularly preferred embodiments. These skeletons are relatively easy to obtain, have a chemically stable structure, and are particularly excellent in reversible repetition (crosslinking and dissociation) of Diels-Alder reaction.

The furan skeleton is not particularly limited, and for example,
The skeleton represented by the following general formula (1) may be mentioned.

[Chemical 1] (R ^{7 to} R ¹⁰ independently of each other represent a group selected from the group consisting of a hydrogen atom, a hydrocarbon group and a lower alkoxyl group, and they may be the same or different;
It is bonded to the skeleton of the basic compound or another furan skeleton at any one of ^{7 to} R ¹⁰ . ) As the hydrocarbon group and the lower alkoxyl group, R ¹ to
The same as described for R ⁶ .

The substituents R ^{7 to} R ¹⁰ are Diels Alder with a compound having an electron donating substituent such as a lower alkyl group and a lower alkoxyl group, an aromatic conjugated substituent such as a phenyl group, or a hydrogen atom having a maleimide described below. A hydrogen atom is preferable from the viewpoint of easy progress of the reaction, and a hydrogen atom is particularly preferable from the viewpoint of the reactivity, availability, dissociation temperature of the Diels-Alder reaction addition part, and the like.

In the first and third aspects of the present invention,
If a functional group such as an isocyanate group and a Diels-Alder reaction addition portion are present in the molecule, the functional group and the Diels-Alder reaction addition portion may be independently introduced into the basic skeleton of the basic compound. As described above, the Diels-Alder reaction addition part may have a substituent capable of reacting with the functional group, and the substituent may be reacted with the functional group to introduce it into the basic compound. From the viewpoint of ease of introduction of the Diels-Alder reaction addition portion, adjustment of the introduction ratio, etc., the Diels-Alder reaction addition portion has a substituent capable of reacting with the functional group, and the substituent and It is preferably introduced into the polymer by reacting with a functional group.

As the compound having a furan skeleton in this case, in the general formula (1), at least one of R ^{7 to} R ¹⁰ is a lower alkyl having a substituent capable of reacting with a functional group such as an isocyanate group described later. It is preferably a group, a phenyl group or a substitution product thereof. These substituents are any one of R ^{7 to} R ^{10 in} the general formula (1).
The substitution position in the furan skeleton of the general formula (1) is not particularly limited and may be the 2-position (R ⁷ or R ¹⁰ ) or the 3-position (R ⁸ or R ⁹ ). The 2-position (R ⁷ or R ¹⁰ ) is preferable from the viewpoints of reduced reactivity due to steric hindrance of Diels-Alder reaction and availability.

As the substituent capable of reacting with the isocyanate group, blocked isocyanate group, alkoxysilyl group and epoxy group, those having at least one active hydrogen are generally preferred. Examples thereof include a hydroxyl group, an amino group (including a monosubstituted nitrogen atom), a mercapto group and a carboxyl group. In addition, as those that do not have active hydrogen,
Examples thereof include acid anhydride groups and latent amino groups.
Specifically, it is a hydroxymethylene group, an aminomethylene group, a methylaminomethylene group, a hydroxyethyl group, an aminoethyl group, a methylaminoethyl group or the like. Examples of the latent amino group include those mentioned above. Such a compound having a furan skeleton having a substituent capable of reacting with a functional group is specifically furfural, furfurylamine,
Examples include furfurylamine blocks, and furfural and furfurylamine are preferable.

The second aspect of the present invention requires polyfuran having two or more furan skeletons. The furan skeleton contained in the polyfuran is a lower alkyl group having a substituent Y bonded to another conjugated diene (furan skeleton) in at least one of R ^{7 to} R ¹⁰ in the general formula (1), a phenyl group, or these. And the like are preferable. These substituents are each represented by R ⁷ to R ^{7 in the} general formula (1).
The substitution position in the furan skeleton of the general formula (1) is not particularly limited as long as it is present in any one of R ^{10 s} , and it may be in the 2-position (R ⁷ or R ¹⁰ ) or the 3-position (R ⁸ or R ^9). ) Is okay. From the viewpoints of reduced reactivity due to steric hindrance of Diels-Alder reaction and availability, etc. 2
Position (R ⁷ or R ¹⁰ ) is preferred. The furan skeletons having two or more may be the same or different.

The substituent Y is not particularly limited. Polyfuran includes, for example, ethylenebisfuran, diphenylbisfuran, diphenylmethanebisfuran, isobutyltrifuran, neopentyltetrafuran, and these are bisfuran and trifuran from the viewpoint of reactivity and availability. Is preferred.

The maleimide skeleton is not particularly limited, and examples thereof include the skeleton represented by the following general formula (2).

[Chemical 2] (In the formula, R ¹¹ and R ¹² are independently of each other a hydrogen atom,
It represents a group selected from the group consisting of a hydrocarbon group and a halogen atom, which may be the same or different and R ¹³ is a hydrocarbon group which may contain a hetero atom. ) The hydrocarbon group for R ¹¹ and R ¹² is the same as described for R ^{1 to} R ⁶ . Examples of the halogen atom include F, Cl, Br and I. Examples of the hydrocarbon group for R ¹³ include the above-mentioned lower alkyl group, an aralkyl group which may contain a hetero atom, and an aryl group which may contain a hetero atom. Specifically, the aralkyl group which may contain a hetero atom is
Examples thereof include a benzyl group, a benzyl ether group, a benzyl thioether group, a benzylamino group, a methylbenzyl group and an ethylbenzyl group. The aryl group which may contain a hetero atom is a phenyl group, a phenyl ether group, an anilino group, a phenyl thioether group. , A methylphenyl group, an ethylphenyl group and the like.

The substituents R ¹¹ and R ¹² are preferable from the viewpoint of facilitating the Diels-Alder reaction with the hydrocarbon group, the hydrogen atom and the halogen atom and the compound having the above-mentioned furan skeleton, and the reactivity and the availability. And a hydrogen atom is particularly preferable from the viewpoint of the dissociation temperature of the Diels-Alder reaction addition part and the like.

The first aspect of the present invention requires a polymaleimide having two or more maleimide skeletons as described above. The maleimide skeleton contained in the polymaleimide has a substituent X which is bonded to another maleimide skeleton in the general formula (2). If there are two or more maleimide skeletons, three-dimensional cross-linking can be performed by the Diels-Alder reaction with the furan skeleton of the first embodiment. The polymaleimide having two or more such maleimide skeletons is not particularly limited, and examples thereof include bismaleimide and trimaleimide. From the viewpoint of easy availability, bismaleimide is preferable, and for example, those represented by the following general formula (3) can be preferably used. The maleimide skeletons having two or more may be the same or different.

[0071]

[Chemical 3] (In the formula, R ^{14 to} R ¹⁷ each independently represent a group selected from the group consisting of a hydrogen atom, a hydrocarbon group and a halogen atom, and may be the same or different. , Represents a group selected from the group listed in Table 3,
In Table 3, p and q represent an integer of 1 or more. ) The hydrocarbon group and the halogen atom are the same as the above R ¹¹ and R
Similar to ¹² . When the substituents R ^{14 to} R ¹⁷ are these groups, it is preferable from the viewpoint that a Diels-Alder reaction with a compound having a furan skeleton easily proceeds, and an electron-withdrawing substituent of a hydrogen atom or a halogen atom is more preferable. A hydrogen atom is particularly preferable from the viewpoints of properties and availability.

[0072]

[Table 3]

[0073]

[Table 4]

[0074]

[Table 5]

[0075]

[Table 6]

Among them, phenylene bismaleimide and 4,4'-bismaleimide diphenylmethane are particularly preferably used from the viewpoints of handleability and dissociation temperature of the Diels-Alder reaction addition part.

In the second and third aspects of the present invention,
If a functional group such as an isocyanate group and a Diels-Alder reaction addition portion are present in the molecule, the functional group and the Diels-Alder reaction addition portion may be independently introduced into the basic skeleton of the basic compound. As described above, the Diels-Alder reaction addition part may have a substituent capable of reacting with the functional group, and the substituent may be reacted with the functional group to introduce it into the basic compound. From the viewpoint of ease of introduction of the Diels-Alder reaction addition portion, adjustment of the introduction ratio, etc., the Diels-Alder reaction addition portion has a substituent capable of reacting with the functional group, and the substituent and It is preferably introduced into the basic compound by reacting with a functional group.

As the compound having a maleimide skeleton in this case, one of R ^{11 to} R ¹³ in the general formula (2) is used.
One is preferably a lower alkyl group having a substituent capable of reacting with a functional group such as an isocyanate group, a phenyl group, or a substitution product thereof. These substituents may be present in any one of R ^{11 to} R ¹³ of the general formula (2), and the substitution position in the maleimide skeleton of the general formula (2) is not particularly limited, and the 1-position It may be (R ¹³ ) or at the 3rd position (R ¹¹ or R ¹² ). The 1-position (R ¹³ ) is preferable from the viewpoints of reduced reactivity due to steric hindrance of Diels-Alder reaction and availability.

Substituents capable of reacting with the isocyanate group, blocked isocyanate group, alkoxysilyl group and epoxy group are the same as the above-mentioned substituents. Such a compound having a maleimide skeleton having a substituent capable of reacting with a functional group is specifically hydroxymaleimide,
Hydroxymethylmaleimide, hydroxyethylmaleimide, hydroxyphenylmaleimide; aminomaleimide, aminomethylmaleimide, aminoethylmaleimide, aminophenylmaleimide; mercaptomaleimide, mercaptomethylmaleimide, mercaptoethylmaleimide, mercaptophenylmaleimide and the like, hydroxymaleimide, hydroxy Phenylmaleimide, aminomaleimide and aminophenylmaleimide are preferred.

In the present invention, the compound (low molecular weight compound, high molecular compound) containing the heat dissociable site has been described, but it can also be used as a curing agent containing the heat dissociable site. That is, by introducing a Diels-Alder reaction addition part into a curing agent used for a prepolymer containing an isocyanate group, an epoxy group, an alkoxysilyl group, etc., decomposition (disassembly) after curing by a functional group such as an isocyanate group is possible. (EN) Provided are a curing agent and a curable resin composition containing the same, which are safe (no toxic gas is generated during thermal decomposition) and can be easily performed. In this case, it forms a cross-link with the resin component and acts as a curing agent. That is, a hydroxyl group capable of reacting with a functional group such as an isocyanate group,
By introducing a heat-dissociable site into a compound having an amino group, a latent amino group, a carboxyl group, etc., even after a curing reaction of a functional group such as an isocyanate group, the heat-dissociable site of the curing agent is thermally decomposed. By doing so, the cured product can be easily decomposed (disassembled).

As such a curing agent, a commonly used group that reacts with an isocyanate group, a blocked isocyanate group, an alkoxysilyl group and an epoxy group, for example, a hydroxyl group, an amino group, a latent amino group, a carboxyl group, etc. There is no particular limitation as long as it is a compound having

Specific examples thereof include a hardening agent having a conjugated diene structure containing a hydroxyl group, an amino group, a carboxyl group and the like and a dienophile structure containing these groups, and the like.
More specifically, a Diels-Alder reaction product of furfuryl alcohol, furfuryl amine, furancarboxylic acid, and phenol maleimide or aniline maleimide can be mentioned. The resin component at this time is not particularly limited as long as it is a curable resin. The method for producing these reactants is not particularly limited, and a commercially available compound may be used under the above-mentioned general Diels-Alder reaction conditions.

The curable resin composition according to claim 4 contains the curable compound. The curable compound of the present invention may be a resin component or a curing agent component. The following are mentioned as a suitable example of the composition of this invention.

(1) Urethane type composition When a urethane compound (low molecular weight compound or high molecular weight compound) having a Diels-Alder reaction addition part in its skeleton is used as the curable compound of the present invention, it can be cured only by moisture. The (one-pack type curable resin composition) may have a hydroxyl group, an amino group, a latent amino group, a mercapto group and a carboxyl group capable of forming a crosslink with the isocyanate group in the skeleton, and a curing agent component. As the compound, a compound having a hydroxyl group capable of forming a cross-link with the isocyanate group, an amino group, a latent amino group, a mercapto group and a carboxyl group, which is commonly used in urethane-based compositions, can be contained. The curing agent component may be used alone or in combination of two or more. Further, the above-mentioned curing agent having a heat dissociable site can be used as the curing agent component, and further, one or more thermosetting resins and their prepolymers or the like are contained in accordance with adjustment of cured physical properties and the like. You can also In addition,
The same applies to a curable compound in which a Diels-Alder reaction addition part is introduced into the skeleton of a block-type urethane compound, in which some or all of the isocyanate groups of the urethane compound are blocked with the above blocking agent. The urethane compound introduced with the Diels-Alder reaction addition portion is preferably the urethane prepolymer described above from the viewpoint of physical properties of a cured product and easiness of handling.

(2) Silicone-based composition When a silane compound (low molecular weight compound or high molecular weight compound) having a Diels-Alder reaction addition portion introduced into its skeleton is used as the curable compound of the present invention, it can be cured only by moisture. The (one-pack type curable resin composition) may introduce a hydroxyl group, an amino group, a latent amino group, a mercapto group and a carboxyl group capable of forming a crosslink with the alkoxysilyl group in the skeleton, and a curing agent As a component, having a hydroxyl group capable of forming a crosslink with the alkoxysilyl group, an amino group, a latent amino group, a mercapto group and a carboxyl group,
It may also contain compounds commonly used in silicone-based compositions. The curing agent component may be used alone or in combination of two or more. Further, the above-mentioned curing agent having a heat dissociable site can be used as the curing agent component, and further, one or more thermosetting resins and their prepolymers or the like are contained in accordance with adjustment of cured physical properties and the like. You can also
The silane compound into which the Diels-Alder reaction addition portion is introduced is preferably the above-mentioned low molecular weight compound and prepolymer from the viewpoint of easy production and easy handling.

(3) Epoxy-based composition When an epoxy compound (low molecular weight compound or high molecular weight compound) in which a Diels-Alder reaction addition part is introduced into the skeleton is used as the curable compound of the present invention, the epoxy group is added to the skeleton. A hydroxyl group capable of forming a crosslink with, an amino group, a latent amino group, a mercapto group, a carboxyl group and an acid anhydride group may be introduced, and a hydroxyl group capable of forming a crosslink with the epoxy group as a curing agent component. A compound having an amino group, a latent amino group, a mercapto group, a carboxyl group and an acid anhydride group, which is commonly used in epoxy compositions, can be contained. The curing agent component may be used alone or in combination of two or more. Further, the above-mentioned curing agent having a heat dissociable site can be used as the curing agent component, and further, one or more thermosetting resins and their prepolymers or the like are contained in accordance with adjustment of cured physical properties and the like. You can also When used as a one-pack type curable resin composition, a latent group or curing agent component generally used is used. The epoxy compound in which the Diels-Alder reaction addition portion is introduced into the skeleton is preferably the above-mentioned epoxy resin and epoxy prepolymer (including an oligomer) from the viewpoint of physical properties of a cured product and easy handling.

(4) Mixed system composition A "mixed system" is a curable composition having two or more different functional groups selected from the group consisting of isocyanate groups, blocked isocyanate groups, alkoxysilyl groups and epoxy groups in the molecule. Refers to a compound. As the curable compound of the present invention,
When using a mixed compound (low molecular weight compound, high molecular weight compound) in which a Diels-Alder reaction addition part is introduced into the skeleton, even if it can be cured only by moisture, the skeleton is cross-linked with any of the above functional groups in the same manner as the above composition. A hydroxyl group capable of forming an amino group, a latent amino group, a mercapto group, a carboxyl group and an acid anhydride group may be introduced, and as a curing agent component, a hydroxyl group capable of forming a crosslink with any of the above functional groups. It may also contain a compound having an amino group, a latent amino group, a mercapto group, a carboxyl group and an acid anhydride group, which is commonly used in the composition. Hardener component is 1
The seeds may be used alone or in combination of two or more. Further, the above-mentioned curing agent having a heat dissociable site can be used as the curing agent component, and further, one or more thermosetting resins and their prepolymers or the like are contained in accordance with adjustment of cured physical properties and the like. You can also When used as a one-pack type curable resin composition, a latent group or curing agent component generally used is used. The term "mixed composition" means
In addition to the composition containing a curable compound containing two or more types of functional groups described above, it refers to a composition containing two or more types of the above-mentioned curable compounds. For example, a composition containing two or more urethane type curable compounds and a composition containing a urethane type curable compound and an epoxy type curable compound may be mentioned. Preferably, the modified prepolymer described above and the like can be mentioned.

In the curable resin composition of the present invention, the curing agent contained in the composition is 1 to 100 parts by mass, preferably 10 to 50 parts by mass, relative to 100 parts by mass of the curable compound.
Parts by mass, particularly preferably 20 to 40 parts by mass. 1
When it is more than 00 parts by mass, the amount of the curing agent is too large and the crosslink density becomes high, and the cured product may be hard and brittle. In some cases, the amount of the curing agent is too small to crosslink and the resin does not cure. When a curing agent having a heat dissociable site is used, its content is 1 to 200 parts by mass, preferably 10 to 100 parts by mass of the curable compound.
100 parts by weight, particularly preferably 20 to 60 parts by weight. If it exceeds 200 parts by mass, the amount of the curing agent is too large and the crosslink density becomes high, and the cured product may be hard and brittle. The cured product may not be decomposed.

The curable resin composition of the present invention may contain one or two or more polymers other than the compound of the present invention within a range not impairing the object of the present invention. Plasticizer, filler, catalyst, solvent, UV absorber, dye, pigment, flame retardant, reinforcing agent, antioxidant, antioxidant, thixotropic agent, surfactant (including leveling agent), dispersant, A compounding agent such as a dehydrating agent, an anticorrosive agent, an adhesion-imparting agent, an antistatic agent or the like may be contained. As these compounding agents and the like, those usually used can be used.

The method for producing the curable resin composition of the present invention comprises:
There is no particular limitation, and a resin component, a curing agent component, and if necessary the above-mentioned compounding ingredients are added to a kneading machine filled with nitrogen gas, and the respective components are sufficiently kneaded under normal pressure to uniformly disperse and produce them. . The curable resin composition thus obtained can be used in a liquid state as it is, or can be stored in a container after cooling and sealing after injection.

The curable resin composition of the present invention thus obtained is capable of dissociating the Diels-Alder reaction addition portion at a relatively low temperature after being cured by a crosslinking reaction resulting from a curing reaction of an isocyanate group or the like. Moreover, since the cured product is stable below the temperature, it can be suitably used for adhesives, sealing agents, sealants and the like in the field of automobiles or civil engineering and construction, and members bonded together using the composition of the present invention are , Can be easily dismantled. Further, the curable resin composition of the present invention is highly practical because it can be applied as a liquid to an adherend or the like.

In the curable resin composition of the present invention, by introducing a Diels-Alder reaction addition portion formed by the Diels-Alder reaction, decomposition (disassembly) after curing by a functional group such as an isocyanate group is safe (heat decomposition). Sometimes it does not generate toxic gas) and can be done easily. Further, by introducing the Diels-Alder reaction addition portion in a specific ratio, the cured product has a high cross-linking strength and a low decomposition temperature (excellent cured property), and is highly practical. Furthermore, by adjusting the introduction ratio of the Diels-Alder reaction addition section, it has physical properties (performance) according to the application and the like.

[0093]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. As the curable compound of the present invention, various prepolymers and compounds were synthesized by the following method and various tests were conducted.

Furfuryl alcohol was a reagent manufactured by Kanto Chemical Co., Inc., and diphenylmethane bismaleimide was a reagent manufactured by Tokyo Kasei Co., Ltd. The bisphenol A type epoxy resin is manufactured by Asahi Denka Kogyo Kaisha (EP-4100E, epoxy equivalent 190), m-xylylenediamine is a reagent manufactured by Kanto Chemical Co., Ltd., and γ-isocyanatopropyltrimethoxysilane is manufactured by Nippon Unicar Co., Ltd. ( Y-5187),
As the dibutylamine used for titration of the isocyanate group, a reagent manufactured by Tokyo Kasei Co., Ltd. was used.

As the urethane prepolymer, 100 g of polypropylene triol (molecular weight 5000), 100 g of polypropylene diol (molecular weight 3000) and 56.3 g of diisononyl adipate (DINA) as a plasticizer were placed in a reaction vessel and dehydrated under reduced pressure at 110 ° C. for 12 hours. , 50
NCO% 1. After cooling to 80 ° C., 25.3 g of MDI was added thereto with stirring and reacted at 80 ° C. for 36 hours.
2258 urethane prepolymer was used.

<Introduction of Diels Alder Reaction Addition Portion> 1) 32.88 g of the above urethane prepolymer (content of isocyanate group: 9.595 mmol), 0.2569 g of furfuryl alcohol (2.618 mmol; 2729 equivalents) was added and the mixture was stirred at room temperature for 12 hours to obtain a furan-modified urethane prepolymer. Here, the isocyanate group of the furan-modified urethane prepolymer was quantified with dibutylamine by the back titration method according to the standard method. As a result, the content of isocyanate groups was 0.653% by mass based on the urethane prepolymer,
46 mol% of the isocyanate groups reacted (including isocyanate groups reacted with water. The same applies hereinafter). To this furan-modified urethane prepolymer, 0.4695 g (1.310 mmol, 0.5 equivalent to furfuryl alcohol) of diphenylmethane bismaleimide was added, and 160
Heat and stir at ℃ for 2 hours to react Diels-Alder,
DA urethane prepolymer 1 (in Table 4, "DAU
-1 ").

2) The above-mentioned urethane prepolymer 39.2.
0.5743 g of furfuryl alcohol (5.840 mm) in 1 g (isocyanate group content 11.38 mmol)
Ol and 0.5131 equivalent to the isocyanate group) were added and stirred at room temperature for 12 hours to obtain a furan-modified urethane prepolymer. Here, the isocyanate group of the furan-modified urethane prepolymer was quantified with dibutylamine by the back titration method according to the standard method. As a result, the content of isocyanate groups was 0.391% by mass based on the urethane prepolymer, and 67 mol% of the isocyanate groups had reacted. To this furan-modified urethane prepolymer, 1.0473 g of diphenylmethane bismaleimide (2.922 m
mol, 0.5 equivalent to furfuryl alcohol), and heated and stirred at 160 ° C. for 2 hours to cause Diels-Alder reaction to obtain DA urethane prepolymer 2 (referred to as “DAU-2” in Table 4). It was

3) The above-mentioned urethane prepolymer 35.3
0.7638 g (7.780 mm) of furfuryl alcohol in 2 g (isocyanate group content 10.30 mmol)
Ol and 0.7553 equivalents based on the isocyanate group) were added and stirred at room temperature for 12 hours to obtain a furan-modified urethane prepolymer. Here, the isocyanate group of the furan-modified urethane prepolymer was quantified with dibutylamine by the back titration method according to the standard method. As a result, the content of the isocyanate group was 0.080% by mass based on the urethane prepolymer, and 93 mol% of the isocyanate group was reacted. To this furan-modified urethane prepolymer, 1.401 g (3.913 mm) of diphenylmethane bismaleimide
ol, 0.5 equivalent to furfuryl alcohol), and heated and stirred at 190 ° C. for 2 hours to cause Diels-Alder reaction to obtain DA urethane prepolymer 3 (referred to as “DAU-3” in Table 4). It was

4) Furfuryl alcohol 7.57 g (7
7.2 mmol, 2 equivalents to maleimide skeleton) and 6.92 g (19.3 m) of diphenylmethane bismaleimide.
(mol) was added to 100 ml of THF and stirred at room temperature for 24 hours to cause Diels-Alder reaction. THF and unreacted furfuryl alcohol were distilled off to obtain an adduct.
Next, 1.50 g of this adduct (0.5 equivalent to the isocyanate group) was added to 35.32 g of urethane prepolymer.
(Isocyanate group content 10.85 mmol) and reacted at 190 ° C. for 2 hours to obtain DA urethane prepolymer 4 (referred to as “DAU-4” in Table 4). Here, the isocyanate group of DA urethane prepolymer 4 was quantified with dibutylamine by the back titration method according to the standard method. As a result, the content of isocyanate groups was 0.755% with respect to the urethane prepolymer, and 61 mol% of the isocyanate groups had reacted.

5) An adduct was obtained in the same manner as in 4) above.
Next, 138.6 g (0.5 mmol) of this adduct was added to 190.0 g (1.0 mmol) of bisphenol A type epoxy resin.
00 mol) and reacted at 120 ° C. for 5 hours to give D
A epoxy polymer (designated as "DAE" in Table 4) was obtained. 50 mol% of the epoxy groups have reacted.

6) An adduct was obtained in the same manner as in 4) above.
Next, 138.6 g (0.5 mmol) of this adduct was added to γ-isocyanatopropyltrimethoxysilane 20.
In addition to 5.3 g (1.000 mol), the mixture was allowed to react at room temperature for 5 hours, and DA alkoxysilane (“D” in Table 4 was used.
AS)). 100 mol% of the isocyanate groups were completely reacted (the introduction rate of the Diels-Alder reaction addition part is 50%).

7) The above-mentioned urethane prepolymer 34.0
To 7 g (isocyanate group content 9.943 mmol), 1.05 g (10.20 mmo) of furfuryl alcohol
1, 1.0258 equivalents relative to the isocyanate group) were added and stirred at room temperature for 12 hours to obtain a furan-modified urethane prepolymer. Here, the isocyanate group of the furan-modified urethane prepolymer was quantified with dibutylamine by the back titration method according to the standard method. As a result, the content of the isocyanate group was 0% with respect to the urethane prepolymer, and 100 mol% of the isocyanate group was completely reacted. To this furan-modified urethane prepolymer was added diphenylmethane bismaleimide 1.401 (3.913 mmol, 0.38 equivalents based on furfuryl alcohol), and 19
The mixture is heated and stirred at 0 ° C. for 2 hours to cause a Diels-Alder reaction, and DA urethane prepolymer 5 (“D” in Table 4 is used).
AU-5 ") was obtained.

<Curing Method> I) Urethane composition (Examples 1 to 4 and Comparative Example 1,
2) Examples 1 to 4 and Comparative Example 1: Each DA urethane prepolymer was allowed to stand in the air at 23 ° C and a humidity of 70% for 24 hours to be moisture-cured. Comparative Example 2: The urethane prepolymer prepared above (fourth
In the table, referred to as “UP”) was left in the air at 23 ° C. and 70% humidity for 24 hours to be moisture-cured.

II) Epoxy composition (Example 5 and Comparative Example 3) Example 5: DA epoxy polymer (DAE) was used as a curing agent in 17 g (0.5 mol) of m-xylylenediamine.
And was cured at room temperature (23 ° C.) for 24 hours. Comparative Example 3: Bisphenol A type epoxy resin (referred to as "BPA" in Table 4) 190.0 g (1.0 mo)
34 g of m-xylylenediamine as a curing agent
(1.0 mol) was used and cured at room temperature (23 ° C.) for 24 hours.

III) Silicone Composition (Example 6 and Comparative Example 4) Example 6: DA alkoxysilane (DAS) is 23
It was moisture-cured for 24 hours at 70 ° C. and 70% humidity. Comparative Example 4: 100 g of γ-isocyanatopropyltrimethoxysilane (referred to as “IPS” in Table 4)
It was left in the air at 23 ° C. and a humidity of 70% for 24 hours to be moisture-cured.

In Table 4, the "introduction rate of the Diels-Alder reaction addition section" means that in the urethane compositions (Examples 1 to 4 and Comparative Examples 1 and 2), the Diels-Alder reaction addition section was It is the ratio (mol%) added to the isocyanate group of the urethane prepolymer, and does not include the ratio of the isocyanate group reacted with water. In the epoxy-based composition (Example 5 and Comparative Example 3), it is the ratio (mol%) in which the Diels-Alder reaction addition part is added to the epoxy group of the epoxy resin. In the silicone-based compositions (Example 6 and Comparative Example 4), the ratio (mol) of the amount (mol) of hydroxyl groups in the introduced Diels-Alder reaction addition part to the sum (mol) of the introduced Diels-Alder reaction addition part and the alkoxysilyl group. %).

<Surface Condition of Cured Product> The surface condition of each cured product was visually confirmed and evaluated. The results are shown in Table 4.
In Table 4, when surface tack could not be confirmed, it was "◎", when it could hardly be confirmed, it was "○", and when it was a little confirmed (when there was no problem at practical level at the level of stickiness) Is indicated by “Δ”, and when confirmed, is indicated by “x”.

<Softening Temperature and Thermal Dissociation Test> A cured product (sheet) obtained by sufficiently curing each composition under the above conditions.
Was heated at 20 ° C. intervals for 15 minutes at each temperature, and the softened or liquefied temperature was measured. The results are shown in Table 4.
In addition, the softened state at this temperature is good, "○" when disassembling the adhered member can be safely and easily, "○" when the member can be disassembled, and "○" when the member cannot be disassembled. X ".

<Gas Generation Test> In the above-mentioned softening temperature measurement, it was confirmed whether gas was generated during softening of each composition. The results are shown in Table 4.

<Adhesion Test> Each composition obtained was cooled and molded into a sheet having a thickness of 2 mm, the sheet was pressure-bonded to an adherend (glass), and cured by each of the above-mentioned methods to prepare a sample. . The adhesiveness to glass was evaluated by a peel test. As for the test method, in the test sample adhered by the above-mentioned method, a notch of about 30 to 50 mm was made along the adhesion interface. Fix this sample with a vise,
While strongly pulling the end of the cured product at an angle of 90 degrees or more so as not to break it with pliers or the like, a notch was quickly made at an angle of about 60 degrees with a knife. At this time, the cutting with the knife was made to reach the surface of the adherend (glass). This operation was repeated 10 times or more, with the intervals between the cuts being set to about 3 to 5 mm. Depending on the state of the notched cured product, the case of interfacial peeling is represented by AF, the case of thin layer cohesive failure is represented by TCF, and the case of cohesive failure is represented by CF. The results are shown in Table 4.

[0111]

[Table 7]

[0112]

According to the present invention, by introducing the Diels-Alder reaction addition portion formed by the Diels-Alder reaction, decomposition (disassembly) after curing is safe (no toxic gas is generated during thermal decomposition) and easy. It is possible to provide a curable compound and a curable resin composition containing the curable compound. Further, by introducing the Diels-Alder reaction addition portion in a specific ratio, a curable compound having a high cross-linking strength of the cured product and a low decomposition temperature (excellent in cured physical properties), and a highly practical curable compound and curing containing the same A resin composition can be provided. Further, by adjusting the introduction ratio of the Diels-Alder reaction addition portion, it is possible to provide a curable compound having physical properties (performance) according to the use and the like and a curable resin composition containing the same.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a curable compound (uncured state) of the present invention.

FIG. 2 is a view showing another example of the curable compound (uncured state) of the present invention.

FIG. 3 is a conceptual diagram showing the crosslinking and decrosslinking (thermal dissociation) reaction of the curable compound of the present invention.

Continued front page    F-term (reference) 4C050 AA03 BB04 CC16 DD07 EE01                       FF02 GG03 HH01                 4J034 CE01 HA01 HA02 HA06 HB06                       HC11 HC32 HC37 JA01 JA42                       QB19 RA07 RA08                 4J035 CA03M CA22M FB01 GA01                       GB01 HA01 LA05 LB01 LB02                       LB03 LB20                 4J036 AA01 CA28 CB22 JA01 JA06                       JA15

Claims (4)

[Claims] 1. A Diels-Alder reaction addition part formed by a Diels-Alder reaction from a conjugated diene structure and a dienophile structure, and a functional group selected from the group consisting of an isocyanate group, a blocked isocyanate group, an alkoxysilyl group and an epoxy group. It has a feature that it can be cured by the functional group, and that the Diels-Alder reaction addition part is dissociated and the cured product can be decomposed (disassembled) by heating the cured product in which the functional group undergoes a crosslinking reaction. Curable compound. 2. The conjugated diene structure is a furan skeleton,
The curable compound according to claim 1, wherein the dienophile structure is a maleimide skeleton. 3. The method according to claim 1, which is obtained by reacting a part of the functional group with the Diels-Alder reaction addition section.
The curable compound according to. 4. A curable resin composition containing the curable compound according to claim 1.