JP2001048948A - Thermosetting resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition having high storage stability and curable at relatively low temperatures by including a specific isocyanate compound. SOLUTION: This composition is obtained by including (A) a blocked isocyanate compound with the blocked isocyanate group bound to a tertiary carbon atom and (B) a polyamine and/or a polyol in the equivalent ratio B/A, (OH and/or NH2/NCO) of pref. 0.2-3; wherein the component A is such that the isocyanate group in the isocyanate group-contg. compound such as tetramethylxylylene diisocyanate is blocked with a well-known blocking agent (e.g. ε-caprolactam), and the polyamine in the component B is pref. an aliphatic polyamine including diamine, while the polyol to be used is e.g. a polyether polyol, polyester polyol, the molecular weight thereof being pref. 100-10,000.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosetting urethane resin composition, and more particularly, to a thermosetting urethane resin composition capable of being cured at a low temperature while maintaining storage stability, and its curing. About the method.

[0002]

2. Description of the Related Art An isocyanate group-containing compound used as a thermosetting urethane composition has high reactivity even at a low temperature such as room temperature. Blocked isocyanate compounds having blocked groups have been used. The blocked isocyanate compound previously blocked by the blocking agent is cured by thermally dissociating the blocking agent by heating in the presence of a so-called active hydrogen compound to regenerate the isocyanate group.

However, if a highly reactive compound is selected as the above active hydrogen compound in order to enhance the curability of the urethane composition, the reactivity of the isocyanate group itself is high.
During storage of the urethane composition, there is a high possibility that both will react, and storage stability is lacking. On the other hand, when a compound having low reactivity or a compound having a high thermal dissociation temperature between an isocyanate group and a blocking agent is selected with emphasis on storage stability, curing at low temperatures becomes difficult, and storage stability and low-temperature curability are difficult. There is a problem that it is not possible to achieve both.

[0004] In order to solve the above problems, various thermosetting urethane resin compositions have been conventionally proposed. For example, JP-A-5-86164 discloses a thermosetting composition comprising a polyamine and a blocked polyisocyanate blocked with a specific blocking agent. In the same gazette, in order to avoid a reaction between a highly reactive polyamine and a blocked polyisocyanate, the blocked polyisocyanate is a blocked polyisocyanate blocked by a specific blocking agent, and the above-mentioned block polyisocyanate is used at room temperature or at an appropriately elevated temperature. A substance substantially insoluble in the polyamine is used to ensure storage stability.

On the other hand, JP-A-10-158353 discloses a one-pack type thermosetting urethane composition containing an isocyanate group block and an amine as main components.
In the same publication, the active amine groups on the surface have a center particle diameter of 2 μm or less as an amine which is a curing agent in order to avoid a reaction between a highly reactive amine and a blocked isocyanate group and to ensure the storage stability of the urethane composition. A fine powder-coated amine coated with a fine powder of

When such a one-part type thermosetting urethane composition is used in a place where heat resistance is required, a method of adding an epoxy resin to the composition may be considered to improve heat resistance. When the urethane composition is stored, the epoxy resin reacts with the curing agent in the composition,
There was a problem that storage stability was lacking.

[0007]

DISCLOSURE OF THE INVENTION The present invention achieves both low-temperature curability and storage stability of a urethane composition by using a specific isocyanate compound, and provides good storage stability.
It is a first object of the present invention to provide a thermosetting urethane resin composition which can be cured at a low temperature.

The present invention also provides a thermosetting urethane resin having excellent storage stability and excellent heat resistance while maintaining low-temperature curability by using a specific compound as a curing agent in the urethane composition. It is a second object to provide a composition.

It is a third object of the present invention to provide a method of curing a thermosetting urethane resin composition which has a high curing rate even at a low temperature and has excellent low-temperature curability.

[0010]

DISCLOSURE OF THE INVENTION The present inventors have found that a highly curable urethane resin composition has an isocyanate group-containing compound, which makes it difficult to achieve both storage stability and low-temperature curability of a thermosetting urethane resin composition. Focusing on the isocyanate group, by increasing the steric hindrance around the isocyanate group, to inhibit the reaction with the curing agent that may occur during storage of the composition, to improve the storage stability, isocyanate group as an isocyanate group-containing compound When a compound having tertiary carbon is used, storage stability is significantly improved as compared with a thermosetting resin composition using a block of an isocyanate compound having an isocyanate group of primary carbon or secondary carbon. In addition, the dissociation temperature between the isocyanate group and the blocking agent is higher than that of the general-purpose isocyanate compound. It decreased by about 30 ° C. to 50 ° C. Te,
It has been found that curing at low temperatures has become possible, and that the curing speed is unexpectedly high even at low temperatures. Further, by using a specific curing agent together with the above-mentioned isocyanate group-containing compound, the storage stability of the thermosetting resin composition is further improved, and even when an epoxy resin is added to the composition, the curing agent and the epoxy resin are used. The present inventors have found that a reaction with a resin at room temperature is prevented beforehand, thereby improving heat resistance while maintaining storage stability, and completed the present invention.

That is, the thermosetting resin composition according to the first aspect of the present invention comprises (A) a blocked isocyanate compound in which a blocked isocyanate group is bonded to a tertiary carbon, and (B) a polyamine and a polyol. And at least one member selected from the group consisting of Here, the above (A) is selected from the group consisting of tetramethylxylylene diisocyanate represented by the following formula (1) and isopropenyl-α, α-dimethylbenzoyl isocyanate represented by the following formula (2). It is preferable that at least one isocyanate compound has an isocyanate group blocked.

[0012]

Embedded image

The above (A) is a urethane prepolymer using an isocyanate compound containing an isocyanate group bonded to a tertiary carbon, and is preferably one in which the isocyanate group is blocked. When a polyol is used as the above (B),
30 mg depending on the type of compound used as (A)
It is preferred to use a polyol containing a hydroxyl value of less than KOH / g or greater than 150 mg KOH / g.

The thermosetting resin composition according to the second aspect of the present invention comprises: (A) a blocked isocyanate compound having a blocked isocyanate group bonded to a tertiary carbon;
(C) a polyamine carboxylate. Here, the thermosetting resin composition of the present invention may further contain an epoxy resin as the component (D).

The above-mentioned compound (A) comprises tetramethylxylylene diisocyanate represented by the following formula (1) and isopropenyl-α, α-
At least one isocyanate compound selected from the group consisting of dimethylbenzoyl isocyanate,
Preferably, the isocyanate group is blocked.

[0016]

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The above compound (A) is preferably a urethane prepolymer using an isocyanate compound containing an isocyanate group bonded to a tertiary carbon, wherein the isocyanate group is blocked. The compound (A) preferably has a dissociation temperature between the isocyanate group and the blocking agent of 70 ° C. or higher.

The method for curing a thermosetting resin composition according to the third aspect of the present invention comprises applying the above-mentioned thermosetting resin composition to an object to be coated, and then applying the resin composition to a temperature of 70 ° C. ~ 16
It is characterized by baking and hardening at a temperature of 0 ° C. for less than 15 minutes.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The thermosetting resin composition according to the first aspect of the present invention is selected from the group consisting of a component (A) which is a blocked isocyanate compound in which a blocked isocyanate group is bonded to a tertiary carbon, and a polyamine and a polyol. And at least one component (B).

<Component (A)> The blocked isocyanate compound used as the component (A) has a blocked isocyanate group bonded to a tertiary carbon. Here, the isocyanate compound having an isocyanate group bonded to a tertiary carbon refers to an isocyanate group-containing compound represented by the following formula (3).

[0021]

Embedded image

Here, R ¹ , R ² and R ³ are organic groups, preferably an alkyl group, an aryl group or an aralkyl group, and more preferably ^two of R ¹ , R ² and R ³ have 1 carbon atoms. -3 lower alkyl groups, and the other one is an aryl group or an aralkyl group. Here, examples of the alkyl group include methyl, ethyl, and propyl groups, examples of the aryl group include phenyl and tolyl, and examples of the aralkyl group include benzyl and the like.

Among the above, the organic group represented by R ¹ or R ³ is preferably a methyl group. A is 2
More preferably, it is a polyfunctional isocyanate compound having two or more isocyanate groups having a tertiary carbon bonded in the molecule. The monoisocyanate compound in which a is 1 is usually used as a mixture with a polyisocyanate compound in which a is 2 or more. The polyisocyanate compounds can be used alone or in combination of two or more. In addition, diisocyanate (a
= 2) and triisocyanate (a = 3) are used in a mixed state.

The compound most preferably used as the above-mentioned isocyanate group-containing compound is tetramethylxylylene diisocyanate (TMXDI manufactured by Mitsui Cytec Co., Ltd.) represented by the following formula (1), particularly m- or p-TMX.
DI or isopropenyl-α, α-dimethylbenzoyl isocyanate (TMI manufactured by Mitsui Cytec), particularly m- or p-isopropenyl-α, α-
It is dimethylbenzoyl isocyanate.

[0025]

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Further, as the isocyanate group-containing compound, a urethane prepolymer using the above isocyanate group-containing compound can be used from the viewpoints of adjusting the viscosity of the resin composition according to the present invention, adjusting the curing reaction rate, and the like.

Examples of the polyol compound that forms the urethane prepolymer include polyether polyols, polyester polyols, other polyols, and mixed polyols thereof as in the case of ordinary polyurethane resin compositions.

Examples of polyether polyols include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, 4,4'-dihydroxyphenylpropane, and 4,4'-dihydroxy. Dihydric alcohols such as phenylmethane; glycerin, 1,1,1-
Polyhydric alcohols such as trimethylolpropane, 1,2,5-hexanetriol and pentaerythritol; diamines such as ethylenediamine and aromatic diamine; and one or more saccharides such as sorbitol, ethylene oxide, propylene oxide, Alkylene oxides such as butylene oxide and styrene oxide;
Polyols obtained by adding a kind or two or more kinds; polyoxytetramethylene oxide and the like.

As the polyester polyol, one or two or more of ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, cyclohexanedimethanol, glycerin, 1,1,1-trimethylolpropane, and other low molecular weight polyols are used. Condensation polymer of at least one species with one or more of glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, terephthalic acid, isophthalic acid, dimer acid, or other low molecular carboxylic acids or oligomeric acids Ring-opening polymers such as propionlactone and valerolactone.

Other polyols include those having a carbon-carbon bond in the main chain such as acrylic polyol, polybutadiene polyol, hydrogenated polybutadiene polyol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol and butane. Diol, pentanediol,
A low molecular polyol such as hexanediol can be preferably used. These polyols may be used alone or in combination of two or more.

When the urethane prepolymer is obtained from the above-mentioned polyol compound and isocyanate group-containing compound, the mixing ratio of the polyol compound and the isocyanate group-containing compound is usually equivalent to NCO / OH ratio of 1.2 to 2.0.
It is preferably 3.0, and more preferably 1.5 to 2.0. In addition, such a urethane prepolymer is obtained by mixing a polyol compound and an isocyanate group-containing compound in the above-described quantitative ratio, and in the presence or absence of a catalyst, at 30 ° C to 120 ° C, preferably at 50 ° C to 100 ° C. It is manufactured by heating and stirring.

The urethane prepolymer preferably used in the thermosetting resin composition according to the first embodiment of the present invention includes polypropylene glycol and the above-mentioned suitably used isocyanate group-containing compound, particularly preferably the following. Tetramethylxylylene diisocyanate represented by the formula (1) or isopropenyl-α represented by the formula (2)
α-dimethylbenzoyl isocyanate

Embedded image A urethane prepolymer having an average molecular weight of 500 to 50,000, more preferably 1,000.
And the mixing ratio of the polypropylene glycol and the isocyanate group-containing compound is NCO / OH
Equivalence ratio of 1.2 to 3.0, more preferably 1.5 to 2.0
Can be mentioned. The use of such a urethane prepolymer sufficiently satisfies the storage stability and low-temperature curability, which are the objects of the present invention, and also provides the cured product with excellent physical properties.

In the thermosetting resin composition according to the first aspect of the present invention, the blocked isocyanate compound used as the component (A) is the above-mentioned isocyanate group-containing compound, and the isocyanate group in the compound is known. Refers to those blocked by the blocking agent.

The blocked isocyanate compound used as the component (A) may contain an unblocked isocyanate group as long as the storage stability and the early curing property, which are the objects of the present invention, can be ensured. it can.

Examples of the blocking agent include phenol, lactam, oxime, active methylene, alcohol, benzotriazole, mercaptan, acid amide, imide, amine, imidazole and urea. be able to. Phenol, cresol, xylenol,
Ethylphenol and the like, lactam blocking agents such as ε-caprolactam, δ-valerolactam, β-butyrolactam and β-propiolactam, and oxime blocking agents such as formamidoxime, acetamidooxime and acetoxime , Methyl ethyl ketoxime, diacetyl monooxime, benzophenone oxime, cyclohexanone oxime, etc., as the active methylene blocking agent, diethyl malonate, dimethyl malonate, ethyl acetoacetate, ethyl acetoacetate, methyl acetoacetate, acetylacetone, etc. as,
Examples include methanol, ethanol, propanol, isopropanol, butanol, 2-ethylhexanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether. Further, preferably phenol-based, lactam-based, oxime-based blocking agent can be mentioned, from the viewpoint of storage stability and low-temperature curability,
70 ° C. dissociation temperature between isocyanate group and blocking agent
Compounds having a temperature of from -160 ° C, especially from 70 ° C to 140 ° C, are preferred. Such blocking agents include, among others, ε-caprolactam and methyl ethyl ketoxime.

<Component (B)> As the component (B) according to the first aspect of the present invention, at least one selected from the group consisting of polyamines and polyols is used. Since polyamine has high reactivity, a resin composition containing polyamine as a curing agent is inferior in storage stability. However, in the present invention, a specific blocked isocyanate compound having high steric hindrance around isocyanate groups is used as component (A). ,
As the component (B), a highly reactive polyamine can be used, whereby the thermosetting resin composition of the present invention can be cured at a high curing rate even at a low temperature.

As the polyamine which can be used as the component (B), any of aromatic or aliphatic polyamines may be used. For example, 4,4'-diaminodiphenylmethane, 2,4'-diaminodiphenylmethane,
3,3′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 2,2′-diaminobiphenyl, 2,4′-diaminobiphenyl, 3,3′-diaminobiphenyl, 2,4-diaminophenol, 2,5 −
Diaminophenol, o-phenylenediamine, m-phenylenediamine, 2,3-tolylenediamine, 2,4
-Tolylenediamine, 2,5-tolylenediamine, 2,
Aromatics such as 6-tolylenediamine, 3,4-tolylenediamine; ethylenediamine, propylenediamine, butylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexamethylenediamine, trimethylhexamethylenediamine; N-aminoethylpiperazine,
1,2-diaminopropane, iminobispropylamine, methyliminobispropylamine, Jeffamine ED manufactured by Sun Techno Chemical Co., represented by the following formula (4)
Polyether skeleton diamine represented by R148, aliphatic polyamine such as MPMD manufactured by DuPont Japan; isophorone diamine, 1,3-bisaminomethylcyclohexane, 1-cyclohexylamino-3-aminopropane, 3-aminomethyl Alicyclic polyamines such as -3,3,5-trimethyl-cyclohexylamine, diamines having a norbornane skeleton represented by NBDA manufactured by Mitsui Chemicals, Inc .; meta-xylylenediamine; polyamide amine having an amino group at a molecular terminal of polyamide; 2,5-dimethyl-2,5-hexamethylenediamine, mensendiamine represented by the following formula (6), 1,4-bis (2-amino-2-methylpropyl) piperazine, represented by the following formula (5) Santechno Chemica having the skeleton of polypropylene glycol (PPG) represented Company made of Jeffamine D230,
Jeffamine series such as Jeffamine D400,
(However, n in the formula (5) is an integer of 0 to 100), 1,12-dodecanediamine, 1,10-decanediamine, 1,8-octanediamine, 1,14-tetradecanediamine, Examples thereof include aliphatic diamines such as 1,16-hexadecanediamine and the like, and one or a mixture of two or more thereof may be used. Preferred are aliphatic polyamines and alicyclic polyamines containing a diamine represented by the following formulas (4) to (6) (where n in the formula (5) is an integer of 0 to 100).

[0038]

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As the polyol which can be used as the component (B), those having an average molecular weight of 100 to 10,000 can be used among the polyol compounds which form a urethane prepolymer. Further, in the thermosetting resin composition according to the first aspect of the present invention, when the component (A) is a block of an isocyanate monomer, the polyol has a hydroxyl value of 30 mgKOH / g is preferable, while when the component (A) is a urethane prepolymer block, the hydroxyl value is 150 mgK.
It is preferred that the polyol is greater than OH / g.

The thermosetting resin set according to the first embodiment of the present invention
The content of the component (B) contained in the composition is determined based on the resin composition
From the viewpoint of the curability and physical properties of the cured product, 1 equivalent of the component (A) is used.
0.2 equivalent to 3 equivalents of component (B) per (NCO equivalent)
Amount (OH equivalent and / or NH _TwoEquivalent), preferably 0.
5 to 2 equivalents.

The thermosetting resin composition according to the second aspect of the present invention comprises a component (A) which is a blocked isocyanate compound having a blocked isocyanate group bonded to a tertiary carbon, and a polyamine carboxylate. (C)
And components. Here, the component (A) contained in the thermosetting resin composition according to the second aspect of the present invention includes:
All the compounds exemplified as compounds that can be used in the thermosetting resin composition according to the first embodiment can be preferably used.

<Component (C)> The thermosetting resin composition according to the second embodiment of the present invention contains a polyamine carboxylate as the component (C). Here, as the polyamine,
All of the polyamines exemplified as compounds that can be used in the thermosetting resin composition according to the first embodiment can be preferably used, and particularly preferably, the above-mentioned formula (4)
Aliphatic polyamines containing a diamine represented by-(6),
Cycloaliphatic polyamines can be used.

Examples of carboxylic acids for converting polyamines into salts include formic acid, acetic acid, decanoic acid, dodecanoic acid, stearic acid, 2-ethylhexanoic acid, adipic acid, azelaic acid, glutaric acid, sebacic acid, succinic acid and the like. Alicyclic carboxylic acids such as aliphatic carboxylic acids, methyltetrahydrophthalic acid, hexahydrophthalic acid and methylhymic acid, and aromatic carboxylic acids such as benzoic acid, toluic acid and phthalic acid. Among these, stearic acid, benzoic acid, and phthalic acid are particularly preferable because they have an excellent balance between storage stability and curability.

The content of the component (C) contained in the thermosetting resin composition according to the second embodiment of the present invention is determined from the viewpoint of the curability of the resin composition, the physical properties of the cured product, and the like. The component (C) is used in an amount of 0.2 equivalent to 3 equivalents (NH ₂ equivalent), preferably 0.5 equivalent to 2 equivalents per equivalent of the component (NCO equivalent).

<Component (D)> The thermosetting resin composition according to the second aspect of the present invention contains, as the component (C), a polyamine blocked with a carboxylic acid.
(D) An epoxy resin can be contained as a component. The thermosetting resin composition according to the second aspect of the present invention,
Even if the epoxy resin is contained, the heat resistance can be increased without impairing the storage stability. Here, as the component (D), an epoxy resin such as a bisphenol A epoxy resin, a bisphenol F epoxy resin, and a phenol novolak epoxy resin can be used, and preferably, a bisphenol A epoxy resin is used. it can.

The content of the component (D) contained in the thermosetting resin composition according to the second embodiment of the present invention is determined from the viewpoint of heat resistance, elasticity and the like of the resin composition. : The component by weight of the component (D) is preferably from 9: 1 to 3: 7, and more preferably from 9: 1 to 5: 5.

<Optional Components> In addition to the above components, the thermosetting resin compositions according to the first and second aspects of the present invention may optionally contain other resin components, fillers and other additives. Can be blended. By blending another resin component as an optional component, it becomes possible to use the thermosetting resin composition of the present invention properly depending on the purpose. In this case, it is natural that the amount of the other resin component is within a range that does not impair the storage stability and the low-temperature curability, which are the objects of the present invention.

The physical properties of the obtained composition of the present invention are further improved by including a filler as an optional component within a range that does not impair the storage stability and low-temperature curability, which are the objects of the present invention. Fillers include calcium carbonate, magnesium carbonate, talc, mica, carbon black,
Silica and the like can be mentioned.

The thermosetting resin compositions according to the first and second aspects of the present invention may contain other additives in addition to the above-mentioned components, as long as the object of the present invention is not impaired. .
Other additives include plasticizers such as dioctyl phthalate, antioxidants such as phenol derivatives, aromatic amine derivatives and piperidine derivatives, and ultraviolet absorption such as 2-hydroxybenzophenones, benzotriazoles and salicylates. And organic pigments such as phthalocyanine and inorganic pigments.

The thermosetting resin compositions according to the first and second aspects of the present invention are directed to one-part thermosetting urethane compositions. It is also possible to use the water-soluble resin composition as a two-part urethane composition.

<Curing Method> Next, a curing method will be described. The method for curing the thermosetting resin composition of the present invention includes applying the thermosetting resin composition according to the above-described first and second aspects to an object to be wrapped, and applying the resin composition after application at 70 ° C. 160
C., preferably baking and curing at a temperature of 110.degree. C. to 140.degree. C. for less than 15 minutes, preferably 10 minutes. By using the thermosetting resin composition according to the first and second aspects of the present invention, which has a low dissociation temperature between the isocyanate group and the blocking agent, it becomes possible to cure at a low temperature. For example, when the thermosetting resin composition of the present invention is used for bonding between glass and a steel plate, after being applied between adherends, the composition is heated at a temperature of 70 ° C to 160 ° C for 10 seconds to 10 minutes and cured. .

As described above, the thermosetting resin composition according to the first embodiment of the present invention uses a blocked isocyanate compound in which a blocked isocyanate group is bonded to a tertiary carbon as the component (A). Therefore, it has excellent storage stability and low-temperature curability. Further, the thermosetting resin composition according to the second aspect of the present invention,
By using a certain compound as a curing agent, storage stability can be further improved while maintaining low-temperature curability, and by including an epoxy resin, heat resistance can be maintained while maintaining storage stability. An excellent composition can be obtained. Further, by using the thermosetting resin composition of the present invention, it becomes possible to cure the resin composition by performing a low-temperature and short-time baking step.

[0053]

EXAMPLES Next, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples.

<Preparation of Thermosetting Resin Composition> The thermosetting resin compositions shown in Tables 1 and 2 were prepared using the following raw materials in the amounts shown in Tables 1 and 2, respectively. I got

<Synthesis of Block Prepolymer> (1) Synthesis of Block Prepolymer 1 Tetramethylxylylene diisocyanate (TMXDI) as an isocyanate compound and polypropylene glycol (PPG) (Exenol 503) as a polyol
0, manufactured by Asahi Glass Co., Ltd., average molecular weight 5000)
8 hours at 80 ° C. using H equivalent ratio = 2.0
The reaction was carried out with stirring to synthesize a urethane prepolymer. Next, ε-caprolactam equivalent to 1.5 times the equivalent of the NCO group was added, and the mixture was heated and stirred at 90 ° C. for 15 hours to obtain a block prepolymer 1 having an average molecular weight of 5,000. (2) Synthesis of block prepolymer A A block prepolymer A having an average molecular weight of 5000 was obtained in the same manner as in (1) except that hexamethylene diisocyanate (HDI) was used as the isocyanate compound. (3) Synthesis of block prepolymer B A block prepolymer B having an average molecular weight of 5,000 was obtained in the same manner as in (1) except that MDI was used as the isocyanate compound.

(4) Synthesis of Block Prepolymer 2 A block prepolymer 2 having an average molecular weight of 5000 was obtained in the same manner as in (1) except that methyl ethyl ketoxime was used as a blocking agent. (5) Synthesis of block prepolymer 3 A block prepolymer 3 having an average molecular weight of 7,000 was obtained in the same manner as in (1) except that the NCO / OH equivalent ratio was 1.7. (6) Synthesis of prepolymer C Prepolymer C having an average molecular weight of 5000 was obtained in the same manner as in (1) except that the isocyanate group was not blocked. (7) Synthesis of block prepolymer D A block prepolymer D having an average molecular weight of 5000 was obtained in the same manner as in (2) except that methyl ethyl ketoxime was used as a blocking agent.

<Preparation of Polyamine Salt> (8) Synthesis of Polyamine Salt 1 Using norbornanediamine as a polyamine and stearic acid as a carboxylic acid, the mixture was reacted in a MEK solvent at room temperature for 1 hour with stirring at a ratio of 1: 2. The precipitated powder was separated by filtration to obtain a polyamine salt 1 having a molecular weight of 723. (9) Synthesis of polyamine salt 2 Polyamine salt 2 having a molecular weight of 554.9 was obtained in the same manner as in (8) except that dodecanoic acid was used as the carboxylic acid. (10) Synthesis of polyamine salt 3 Polyamine salt 3 having a molecular weight of 498.9 was obtained in the same manner as in (8) except that benzoic acid was used as the carboxylic acid. (11) Synthesis of polyamine salt 4 Polyamine salt 4 having a molecular weight of 320 was obtained in the same manner as (8) except that phthalic acid was used as the carboxylic acid and the ratio was 1: 1.

[0058]

[Table 1]

However, polyamine 1 is represented by the following formula (4) (Jeffamine EDR148, manufactured by San Techno Chemical Co.), and polyamine 2 is represented by the following formula (5) (where n is about 5.6)
) (Jeffamine D400, manufactured by San Techno Chemical Co., Ltd.), wherein polyamine 3 is mensendiamine represented by the following formula (6), and polyamine 4 is norbornanediamine.

Embedded image Polyol 1 is polypropylene glycol (Exenol 430, manufactured by Asahi Glass Co., Ltd., hydroxyl value 386 mg KO
H / g).

[0060]

[Table 2] However, a bisphenol A type epoxy resin (EP4100E, manufactured by Asahi Denka Co., Ltd.) was used as the epoxy resin.

<Dissociation Temperature Test> Block prepolymers 1, A and B before blocking were blocked with a blocking agent shown in Table 1, and then the polymer was heated to dissociate the isocyanate groups with the blocking agent. The temperature was measured and the results are shown in Table 3.

[0062] It can be seen that the blocked isocyanate compound in which the blocked isocyanate group is bonded to the tertiary carbon has a lower dissociation temperature with the blocking agent than other blocked isocyanate compounds. This shows that the thermosetting resin composition of the present invention enables low-temperature curability as described above.

<Storage stability test> In order to examine the storage stability of the thermosetting resin composition thus prepared, the composition was allowed to stand in a sealed container at a temperature of 40 ° C to 60 ° C for 7 days. Table 4 shows the thickening ratio after 7 days when the viscosity of the composition immediately after preparation was set to 1.

[0064]

[Table 3]

<Low-temperature curing property test> Next, in order to examine the low-temperature curing property of the thermosetting resin composition, the thermosetting resin composition prepared as described above was applied on a stainless steel plate, and the baking temperature was determined. The time required for the composition to cure at 130 ° C and 140 ° C was examined. Table 5 shows the results.

[0066]

[Table 4]

If the thickening ratio after 7 days is not more than twice the viscosity immediately after the preparation of the composition, it is considered that the composition usually has storage stability, and the heat according to the first and second aspects of the present invention is considered. It can be seen that the curable resin composition exhibits excellent storage stability. A comparison between a composition using polyamine 4 which is norbornanediamine as a curing agent (Example 5) and a composition using polyamine salt 1 which is a stearic acid salt of norbornanediamine (Example 7) shows that Example The thickening factor of 7 is 0.2 lower than that of Example 5, and the storage stability of the thermosetting resin composition is extremely good by using a polyamine salt as a curing agent. It can be understood that The curing time required for baking the thermosetting composition according to the first and second aspects of the present invention is less than 15 minutes, and at 140 ° C., both are 8 minutes or less. It can be seen that the thermosetting resin composition according to the invention cures in a short time.

<Heat Resistance Test> Next, in order to examine the heat resistance of the thermosetting resin composition according to the second embodiment of the present invention, the thermosetting resin compositions of Examples 7 to 12 were placed on a stainless steel plate. After each application and curing at 140 ° C. for 10 minutes, 16
It was left in a thermostat at 0 ° C. for 1 hour, and the state of the cured product was observed. Due to prolonged exposure to high temperature, the cured product of the resin composition of Example 7 was softened.
The cured products of the resin compositions of Examples 8 to 12 did not show any deformation. This indicates that a thermosetting resin composition having excellent heat resistance can be obtained while maintaining storage stability and low-temperature curability by containing an epoxy resin.

[0069]

The thermosetting resin composition according to the first aspect of the present invention is capable of curing at a low temperature while having excellent storage stability. The thermosetting resin composition according to the second aspect of the present invention, by containing an epoxy resin, can exhibit excellent heat resistance while maintaining storage stability and low-temperature curability, for example, heat resistance The resin composition of the present invention can be optimally used as an adhesive or a sealant between parts of an automobile in an automobile assembly line that requires the following. Further, according to the method for curing a thermosetting resin composition according to the third aspect of the present invention, the baking temperature can be relatively low, and the thermosetting resin composition can be cured in a short time. Can be done.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J034 BA06 BA07 BA08 CA04 CA15 CB03 CC03 CC08 CC12 CC23 CC26 CC28 CC33 CC45 CC52 CC61 CD04 DB03 DC02 DC35 DC43 DC50 DF01 DF11 DF16 DG03 DG04 DG05 DG06 DG08 DG09 DK05 HC12 HA04 HC52 HC61 HC73 HD03 HD04 HD05 HD07 HD12 HD15 QC05 RA07

Claims (12)

[Claims] 1. A method comprising: (A) a blocked isocyanate compound in which a blocked isocyanate group is bonded to a tertiary carbon; and (B) at least one selected from the group consisting of polyamines and polyols. Thermosetting resin composition. 2. The compound (A) is selected from the group consisting of tetramethylxylylene diisocyanate represented by the following formula (1) and isopropenyl-α, α-dimethylbenzoyl isocyanate represented by the following formula (2). The thermosetting resin composition according to claim 1, wherein the at least one isocyanate compound selected has an isocyanate group blocked. Embedded image 3. The compound (A) is a urethane prepolymer using an isocyanate compound containing an isocyanate group bonded to the tertiary carbon, wherein the isocyanate group is blocked. The thermosetting resin composition according to claim 1. 4. The thermosetting resin composition according to claim 1, wherein (B) is a polyamine. 5. The thermosetting resin composition according to claim 1, wherein (B) is a polyol having a hydroxyl value of less than 30 mg KOH / g or more than 150 mg KOH / g. object. 6. The thermosetting resin composition according to claim 1, wherein said compound (A) has a dissociation temperature between an isocyanate group and a blocking agent of 70 ° C. or higher. . 7. A thermosetting resin composition comprising: (A) a blocked isocyanate compound in which a blocked isocyanate group is bonded to a tertiary carbon; and (C) a carboxylate of a polyamine. . 8. A method comprising: (A) a blocked isocyanate compound in which a blocked isocyanate group is bonded to a tertiary carbon; (C) a carboxylate of a polyamine; and (D) an epoxy resin. Thermosetting resin composition. 9. The compound (A) is selected from the group consisting of tetramethylxylylene diisocyanate represented by the following formula (1) and isopropenyl-α, α-dimethylbenzoyl isocyanate represented by the following formula (2). The thermosetting resin composition according to claim 7, wherein the at least one isocyanate compound selected is one in which an isocyanate group is blocked. Embedded image 10. The compound (A) is a urethane prepolymer using an isocyanate compound containing an isocyanate group bonded to the tertiary carbon, wherein the isocyanate group is blocked. The thermosetting resin composition according to claim 7. 11. The thermosetting resin composition according to claim 7, wherein the compound (A) has a dissociation temperature between an isocyanate group and a blocking agent of 70 ° C. or higher. . 12. A thermosetting resin composition according to any one of claims 1 to 11, which is applied to an object to be baked and baked at 70 to 160 ° C. for less than 15 minutes. And curing the thermosetting resin composition.