JP2010077245A - Low-temperature curable composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-temperature curable composition that can be cured at a relatively low temperature of about 200°C or lower. <P>SOLUTION: The low-temperature curable composition contains a triaza cyclic compound expressed by formula (1), a phenolic compound and a solid epoxy resin having a softening temperature of 60°C or higher measured in accordance with JISK7234. In formula (1), R represents a ≤10C organic group. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a low-temperature curable composition. Specifically, the present invention relates to a low temperature curable composition containing a triaza ring compound.

  Conventionally, benzoxazine has been known as a compound that undergoes ring-opening polymerization and thermosets, and as a technique relating to benzoxazine and a benzoxazine polymer and a specific production method, the benzoxazine is a phenol component, an amino component, and It is disclosed that it is synthesized from formaldehyde (see, for example, Patent Document 1).

  As another method for producing benzoxazine, a compound having a triaza ring (1,3,5-triphenylhexahydro-1,3,5-triazine, hereinafter referred to as hexahydro- A compound having a 1,3,5-triazine ring is abbreviated as “triaza ring compound”), and then this triaza ring compound is reacted with bisphenol A to give a benzoxazine representative benzoxazine monomer ( 6,6 ′-(1-methylethyliden) bis (3,4-dihydro-3-phenyl-2H-1,3-benzoxazine) (hereinafter abbreviated as Ba) has been disclosed. For example, refer nonpatent literature 1.).

  The benzoxazine such as Ba has an advantage that a polymer and a molded body using the same have high heat resistance.

JP 49-47378 A Zdenka Brunovska, Macromol. Chem. Phys. Vol. 200, p.1745-1752 (1999)

  However, for example, when a composition containing a general-purpose thermosetting resin such as an epoxy resin and benzoxazine is thermally cured, the curing temperature of the benzoxazine is as high as 200 ° C. or higher, so that the epoxy resin deteriorates in the curing process. There is a problem of disassembling and disassembling.

  Therefore, in view of the above-described conventional circumstances, the present invention provides a so-called low-temperature curable composition that can be cured under a relatively low temperature condition of 200 ° C. or lower.

As a result of intensive studies on the above-mentioned problems of the prior art, the present inventors have found that a composition comprising a triaza ring compound, a phenol compound, and an epoxy resin can be cured at a low temperature of 200 ° C. or lower. The headline and the present invention were completed.
In invention of Claim 1, the low temperature curable composition containing the triaza ring compound shown in following formula (1), a phenol compound, and an epoxy resin solid at normal temperature is provided.
The normal temperature is 20 ° C. ± 15 ° C., and the solid state is defined as a softening temperature measured by JISK7234 of 60 ° C. or higher.

  In the formula (1), R is an organic group having 10 or less carbon atoms.

  In invention of Claim 2, R in said Formula (1) provides the low temperature curable composition of Claim 1 which is a phenyl group.

  The invention according to claim 3 provides the low-temperature curable composition according to claim 1, wherein the phenol compound is resorcinol.

  In the invention of claim 4, R in the above formula (1) is any organic group selected from the group consisting of methyl, propyl, butyl, furfuryl, allyl, and phenyl, a cyano group, an isocyanate group, 2. The low-temperature curable composition according to claim 1, which is an organic group that may contain at least one functional group having no active hydrogen selected from the group consisting of vinyl groups.

According to the present invention, there is provided a low-temperature curable composition that can be dramatically cured under a low-temperature condition as compared with a composition composed of benzoxazine (Ba) described above in the prior art.
Moreover, the high intensity | strength molded object is obtained by thermosetting the low-temperature-curable composition of this invention.

  Hereinafter, the best mode for carrying out the present invention (hereinafter, this embodiment) will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.

The low-temperature curable composition in this embodiment contains a triaza ring compound represented by the following formula (1), a phenol compound, and an epoxy resin that is solid at room temperature.
The present embodiment is characterized in that an epoxy resin that is solid at room temperature is used.
Here, normal temperature means 20 ° C. ± 15 ° C.
Further, the solid state means that there is no fluidity, and specifically, a softening temperature measured by JISK7234 is 60 degrees or more.

  In the formula (1), R is an organic group having 10 or less carbon atoms.

The low temperature curable composition in this embodiment contains the solid epoxy resin whose softening temperature measured by JISK7234 is 60 degreeC or more as mentioned above. A solid epoxy resin having a softening temperature of 60 ° C. or higher is solid at ordinary temperature (20 ° C. ± 15 ° C.) and has a property of becoming a low-viscosity liquid when heated to a temperature higher than the softening point temperature. Therefore, when the low-temperature curable composition is heated to a temperature higher than the softening temperature of a solid epoxy resin having a softening temperature of 60 ° C. or higher, it becomes a low-viscosity liquid of 1000 Pa · s or more and can be easily subjected to injection molding or the like. It becomes like this.
That is, the low-temperature curable composition can be melt-mixed without using a solvent, which is environmentally desirable, and volume shrinkage due to volatilization of the solvent does not occur, so that dimensional accuracy can be increased.
Moreover, since the low temperature curable composition in this embodiment cures at 200 ° C. or lower and cures reliably at about 200 ° C., it is possible to prevent deterioration and decomposition of the compounds constituting the composition.
Hereinafter, the compound which comprises the low temperature curable composition in this Embodiment is demonstrated in detail.

[Triaza ring compound]
The triaza ring compound is represented by the following formula (1).

In formula (1), R is an organic group having 10 or less carbon atoms.
As R, for example, a saturated or unsaturated linear or branched hydrocarbon group such as an alkyl group having 1 to 10 carbon atoms, an alkenyl group, and an alkynyl group; saturated such as a cycloalkyl group having 3 to 10 carbon atoms Or an unsaturated cyclic hydrocarbon group; a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms; a substituted or unsubstituted heteroaromatic group containing a heteroatom such as nitrogen, oxygen or sulfur having 6 to 10 carbon atoms A cyclic group etc. are mentioned.
Specifically, R can be any organic group selected from the group consisting of a methyl group, a propyl group, a butyl group, a furfuryl group, an allyl group, and a phenyl group. These may contain a functional group having no active hydrogen selected from the group consisting of a cyano group, an isocyanate group, and a vinyl group.

The triaza ring compound represented by the formula (1) is obtained by a reaction between a monoamine and formaldehyde.
The monoamine is not particularly limited as long as it is an amine having an organic group having 10 or less carbon atoms. Examples include methylamine, ethylamine, propylamine, allylamine, furfurylamine, aniline, methylaniline, aminophenylacetylene, and aminobenzonitrile. Of these, aniline is preferred from the viewpoint of excellent heat resistance and low cost.

  The method for synthesizing the triaza ring compound represented by the formula (1) is not particularly limited and can be a conventionally known method. For example, while heating in a solvent such as THF (tetrahydrofuran) and toluene, The method of making it react with formaldehyde is mentioned.

[Phenol compound]
A phenol compound means the compound which contains a phenol group in a molecule | numerator.
Examples of the phenol compound include monophenol compounds such as phenol, cresol, and xylenol; bisphenol compounds such as hydroquinone, bisphenol A, bisphenol F, bisphenol AF, and bisphenol S; various novolak resins; phenol aralkyl resins, and the like.
In addition to the above, resorcinol, catechol, hydroquinone, pyrogallol having two or more phenolic hydroxyl groups in one benzene ring, and dihydroxynaphthalene having two or more phenolic hydroxyl groups in a naphthalene ring may be mentioned.
Of these, resorcinol is particularly preferable from the viewpoint that a composition curable at a low temperature can be obtained.

〔Epoxy resin〕
As the epoxy resin, a solid epoxy resin at room temperature is applied.
Generally, examples of the epoxy resin include glycidyl ether type epoxy resins (bisphenol A type, bisphenol F type), glycidyl ester type epoxy resins, polyfunctional epoxy resins, polymer type epoxy resins, biphenyl type epoxy resins, and the like. The low-temperature curable resin composition in this embodiment contains a solid epoxy resin at room temperature.
The normal temperature is (20 ° C. ± 15 ° C.).
The solid state means that there is no fluidity. Specifically, it means that the softening temperature measured by JISK7234 is 60 degrees or more.
When an epoxy resin that is liquid at room temperature is used, the other components (triaza ring compound, phenol compound) are gradually dissolved in the epoxy resin and the reaction proceeds. When the epoxy resin is solid, the three components are not mixed with each other, and the pot life of the target low-temperature curable composition is maintained. That is, the progress of the reaction can be suppressed, and the stability as the composition is increased.
Epoxy that is solid at room temperature includes polyfunctional epoxy resin and polymer epoxy resin. Specifically, EPICLON EXA7200 is a tricyclodecane type polymer epoxy resin.
(Dainippon Ink Co., Ltd., trade name), naphthalene ring type polyfunctional epoxy resin, EPICLON EXA9900 (Dainippon Ink Co., Ltd., trade name), novolac type polymer epoxy resin, NC-3000FH (Nippon Kayaku Co., Ltd., brand name) etc. are mentioned.

In the low-temperature curable composition of this embodiment, an example of the expected three-component curing mechanism described above will be described with reference to the following scheme 1.
The epoxy resin is assumed to be solid.
(Scheme 1)

  The low temperature curable composition in the above (Scheme 1) contains a triaza ring compound represented by the above formula (1), a phenol compound represented by the following formula (2), and an epoxy resin represented by the following formula (3).

In the formula (2), R ₂ is a group selected from the following group A.
(Group A)

  The same reaction proceeds even when a compound such as resorcinol having a phenolic hydroxyl group attached to the same benzene ring is used in place of the bisphenol represented by the above formula (2).

In the formula (3), R ₃ can be arbitrarily selected, but the epoxy resin needs to be solid.

The triaza ring compound represented by the above formula (1) is considered to be added to the benzene ring of the phenol compound represented by the above formula (2) after the ring opening. Moreover, it is thought that the activated amino group produced | generated in that case and the epoxy group of the epoxy resin shown in said Formula (3) react.
That is, it is considered that the polymer as shown in the above (Scheme 1) can be obtained by thermosetting the low-temperature curable composition in the present embodiment.

In the low-temperature curable composition of the present embodiment, the equivalent of the phenol functional group is preferably 1 to 5 molar equivalents in terms of equivalents of the phenol functional group with respect to 1 molar equivalent of the triaza ring compound represented by the formula (1). Therefore, it is preferable to mix the phenol compound so as to satisfy the range.
When the phenol functional group is less than 1 molar equivalent, the triaza ring represented by the formula (1) does not open, and the low temperature curable composition may not be cured.
On the other hand, when there are more phenol functional groups than 5 molar equivalent, there exists a possibility that heat resistance physical properties, such as a glass transition point and heat-resistant decomposition property, may fall because a crosslinking density falls.

In the low temperature curable composition of this embodiment, it is preferable that the equivalent of an epoxy functional group is 1-5 molar equivalent in conversion of the equivalent of an epoxy functional group with respect to 1 molar equivalent of the triaza ring compound shown to Formula (1). Therefore, it is preferable to mix the epoxy resin so as to satisfy the range.
When the epoxy functional group is less than 1 molar equivalent, the epoxy group that reacts with the amino group generated by the opening of the triaza ring shown in formula (1) is insufficient, and the crosslinking density decreases, so that the glass transition point is reduced. And heat resistant physical properties such as heat decomposability may be reduced.
On the other hand, when there are more epoxy functional groups than 5 molar equivalent, the epoxy group which does not contribute to reaction remains, and there exists a possibility that heat resistance physical property may fall.

〔Production method〕
The low temperature curable composition in the present embodiment can be produced by mechanically mixing the above three components for several minutes. The production process may be performed by mixing the three components in a solvent as necessary.
The solvent is not particularly limited, and a conventionally known solvent can be used, and examples thereof include toluene and methyl ethyl ketone.
The mixing process of the three components may be performed using various kneaders. Examples of the kneading machine include a stone mill type raking machine, a ball mill, a roll mill, a kneader, and a screw type kneading machine.
From the viewpoint of suppressing the volatilization of the solvent, it is preferable to mix the three components without adding the solvent component.

[Molded body]
The low-temperature curable composition in the present embodiment can be molded by a conventionally known method.
For example, a low-temperature curable composition is heated and melted at 120 to 200 ° C. for 30 minutes to 2 hours, and then subjected to a predetermined molding process to obtain a molded body. You may process into a desired shape using a metal mold | die etc.
As shown in the heat curing mechanism (Scheme 1) of the low-temperature curable composition, the molded body using the low-temperature curable composition in the present embodiment is composed of the triaza ring compound of the above formula (1) and the phenol compound. By reacting first, the resulting amino group and then the epoxy group of the epoxy resin react to form a chemical bond between the three components, and curing is considered to proceed, making it very strong.

[Use of molded body]
Since the molded body using the low-temperature curable composition in the present embodiment is excellent in heat resistance and mechanical strength, electrical / electronic parts, automobile parts, copper-clad laminated boards, printed boards, fire-resistant coatings, composite matrix resins, etc. Available as

  Hereinafter, the present invention will be described in more detail with reference to specific examples and comparative examples. However, the present invention is not limited to the examples described below.

Measurement methods and measurement conditions applied in Examples and Comparative Examples described later are shown.
〔Measuring method〕
(1) Proton nuclear magnetic resonance spectrum ( ¹ H-NMR spectrum)
Using a measuring apparatus (manufactured by JEOL Ltd., model number JNM-ECX), ¹ H-NMR (400 MHz) and deuterium chloroform were used, and the measurement was performed under the conditions of 256 integration and relaxation time of 10 seconds.

(2) Differential scanning thermal analysis (DSC)
Using a thermal analyzer (manufactured by Shimadzu Corporation, model number DSC-60), the temperature increase rate was 10 ° C./min, and the measurement was performed in nitrogen.

(3) Thermogravimetric analysis (heat-resistant decomposition)
Using a thermogravimetric analyzer (manufactured by Shimadzu Corporation, model number DTG-60), the temperature rising rate was set to 10 ° C./min.
The temperature at which the 5% weight loss was 300 ° C. or higher was judged to be practically good.

(4) Tensile Strength Using Instron Universal Test Equipment (Tell me the maker name: Model 5565), sheets of Example 1 and Comparative Examples 1 to 3 described later are sample pieces (Type V ASTM D6-38-03). And the tensile speed was 1 mm / min.
If the tensile strength was 70 MPa or more, it was judged to be practically good.

[Example 1]
(Production of triaza ring compound represented by formula (1))
To a 300 mL round bottom flask equipped with a reflux condenser, 74.4 g of aniline (Wako Pure Chemical), 64.8 g of 37% by weight formaldehyde (Wako Pure Chemical) and 180.0 g of tetrahydrofuran (Wako Pure Chemical) were added and stirred. However, the temperature of the oil bath was raised to 90 ° C., and the reaction was continued for 30 minutes while refluxing the solvent. Thereafter, the reaction mixture was cooled to room temperature. As a result, deposition of the synthesized triaza ring compound was confirmed. The obtained triaza ring compound was 83 g, and the yield was 80%.
This solution (liquid containing the deposit) was put into 2 L of methanol that was vigorously stirred, and the precipitated solid was filtered, and then further washed with methanol to obtain a powder.
The obtained powder was vacuum-dried for 24 hours in a vacuum oven heated to 40 ° C. to obtain a triaza ring compound.
When the ¹ H-NMR spectrum of this triaza ring compound was measured by the method (1) described above, the result shown in FIG. 1 was obtained.
A sharp resonance absorption of the methylene group of the triaza ring was observed in the region of about 4.9 ppm, and it was confirmed that the triaza ring compound was produced.

(Production of low-temperature curable composition)
10.0 g of the triaza ring compound produced as described above, 5.0 g of resorcinol (Wako Pure Chemical Industries), and a polymer epoxy resin solid at 25 ° C. (epoxy group equivalent 281, EPICLON EXA7200HH Dainippon Ink 25.0 g of a solid product (softening point: about 90 ° C.) manufactured by Co., Ltd., was kneaded for 10 minutes using a stone mill type machine to prepare a low-temperature curable composition.
Thermal analysis of this low-temperature curable composition was performed by the method (2) described above, and the curing characteristics were evaluated. FIG. 2 shows a thermal analysis DSC curve.
In addition, the peak temperature of the heat generated by curing (the uppermost portion of the DSC curve was defined as the peak temperature of the heat generated by curing) is shown in Table 1 below.
Moreover, about the pot life (storage stable time) of this low-temperature curable composition, the fluidity | liquidity when heating to 100 degreeC after standing for a predetermined number of days at normal temperature was visually observed and evaluated. Table 1 shows the number of days left at room temperature when the fluidity when heated to 100 ° C is lost.

(Preparation of sheet with low-temperature curable composition)
Between a heating press (Toyo Seiki Co., Ltd. 30t heating / cooling press) controlled at 180 ° C., sandwiched between two polyimide films that have been subjected to a release treatment, and manufactured at a low temperature. And left to thicken for 5 minutes.
Next, a heat curing treatment was performed for 30 minutes while applying a pressure of 10 gf / cm ² by the heating press, followed by cooling. Thereby, a low-temperature curable composition sheet having a thickness of 0.1 mm was obtained.
The thermal decomposition resistance (5% weight loss temperature) of the low-temperature curable composition sheet was measured by the method (3), and the tensile strength was measured by the method (4). These results are shown in Table 1 below.

[Comparative Example 1]
Benzoxazine (Ba type benzoxazine monomer manufactured by Shikoku Kasei Co., Ltd.) was used as Comparative Example 1.
The thermal analysis of benzoxazine Ba was performed by the DSC method of (2) described above, and the curing characteristics were evaluated. Table 1 shows the peak temperature of the heat generated by curing.

(Production of sheet)
Benzoxazine Ba is sandwiched between two release-treated polyimide films and placed between 220 ° C controlled heating press (Toyo Seiki Co., Ltd. 30t heating / cooling press) and left for 5 minutes. To increase the viscosity.
Next, a heat curing treatment was performed for 30 minutes while applying a pressure of 10 gf / cm ² by the heating press, followed by cooling. Thereby, a sheet of benzoxazine Ba having a thickness of 0.1 mm was obtained.
The thermal decomposition resistance (5% weight loss temperature) of this benzoxazine Ba sheet was measured by the method (3) above, and the tensile strength was measured by the method (4) above. These results are shown in Table 1 below.

[Comparative Example 2]
(Manufacture of resin composition)
Benzoxazine Ba (Shikoku Kasei Co., Ltd.) 10.0 g and BisA type glycidyl ether type epoxy resin (epoxy group equivalent 186, EPON 828, Shell Chemical Co., Ltd.) 10.0 g A paste-like resin composition was prepared by kneading for 10 minutes using a machine.
Thermal analysis of this resin composition was performed by the method (2) described above, and the curing characteristics were evaluated. The exothermic peak temperature in DSC is shown in Table 1 below.

(Preparation of sheet by resin composition)
A resin composition prepared by mixing the above-described benzoxazine Ba (manufactured by Shikoku Kasei Co., Ltd.) and BisA type glycidyl ether type epoxy resin (epoxy group equivalent 186, EPON 828, manufactured by Shell Chemical Co., Ltd.) Then, it was placed in a heating press (Toyo Seiki Co., Ltd. 30t heating / cooling press) that was subjected to mold release treatment and controlled at 220 ° C., and was allowed to stand for 5 minutes to increase the viscosity.
Next, a heat curing treatment was performed for 30 minutes while applying a pressure of 10 gf / cm ² by the heating press, followed by cooling. Thereby, a resin composition sheet having a thickness of 0.1 mm was obtained.
The thermal decomposition resistance (5% weight loss temperature) of this resin composition sheet was measured by the method (3) above, and the tensile strength was measured by the method (4) above. These results are shown in Table 1 below.

[Comparative Example 3]
(Production of low-temperature curable composition)
10.0 g of triaza ring compound produced as described above, 5.0 g of resorcinol (Wako Pure Chemical Industries), and BisA type glycidyl ether type epoxy resin (liquid at room temperature: 1100 mPa · s at 25 ° C., epoxy group equivalent 186, 17.0 g of EPON 828 (manufactured by Shell Chemical Co., Ltd.) was kneaded for 10 minutes by using a stone mill type machine to prepare a grease-like low-temperature curable composition at 25 ° C.
Thermal analysis of this low-temperature curable composition was performed by the method (2) described above, and the curing characteristics were evaluated. FIG. 3 shows a thermal analysis DSC curve.
The peak temperature of the heat generated by curing was measured and is shown in Table 1 below.
Moreover, about the pot life (storage stable time) of this low-temperature curable composition, the fluidity | liquidity when heating to 100 degreeC after standing for a predetermined number of days at normal temperature was visually observed and evaluated. Table 1 shows the number of days left at room temperature when the fluidity when heated to 100 ° C is lost.

(Preparation of sheet with low-temperature curable composition)
The low-temperature curable composition produced as described above is placed between a heating press (Toyo Seiki Co., Ltd. 30t heating / cooling press) that has been subjected to a release treatment and controlled at 180 ° C., and is left for 5 minutes. To increase the viscosity.
Next, a heat curing treatment was performed for 30 minutes while applying a pressure of 10 gf / cm ² by the heating press, followed by cooling. Thereby, a low-temperature curable composition sheet having a thickness of 0.1 mm was obtained.
The thermal decomposition resistance (5% weight loss temperature) of the low-temperature curable composition sheet was measured by the method (3), and the tensile strength was measured by the method (4). These results are shown in Table 1 below.

As shown in Table 1, in Comparative Examples 1 and 2 which are resin compositions using a mixture of benzoxazine Ba typical of benzoxazine and an epoxy resin, which is representative in the prior art, both of the exothermic peak temperatures of curing Is 200 ° C. or higher.
On the other hand, the low-temperature curable composition of Example 1 has a curing exothermic peak temperature of 200 ° C. or lower, and is compared with the resin composition using benzoxazine Ba of Comparative Examples 1 and 2 as the prior art. Can be cured at low temperatures. In addition, the pot life is long, the composition is stable, and the handleability is very good.
Moreover, according to the DSC curve of Example 1 shown in FIG. 2, the melting temperature peak of solid epoxy is seen at around 60 ° C. Since the curing reaction starts at a temperature exceeding the melting temperature, the low-temperature curable composition of Example 1 is excellent in storage stability in a normal temperature environment.
In Comparative Example 3 using a liquid epoxy, the curing exothermic peak temperature is low and the low-temperature curability is good, but the pot life is short, and the stability as a composition is inferior to that of Example 1.

  Furthermore, as shown in Table 1, the molded body using the low-temperature curable composition of Example 1 is practically used in comparison with the molded body using the resin compositions according to the prior art (Comparative Examples 1 to 3). It has sufficient heat resistance and mechanical strength.

The proton nuclear magnetic resonance spectrum (< ¹ > H-NMR spectrum) of the triaza ring compound manufactured in Example 1 is shown. The thermal analysis DSC curve of the low temperature curable composition of Example 1 is shown. The thermal analysis DSC curve of the low-temperature curable composition of the comparative example 3 is shown.

  The low-temperature curable composition of the present invention is excellent in heat resistance and mechanical strength, and is industrially used as an electrical / electronic component, automobile component, copper-clad laminate, printed circuit board, fireproof coating, composite matrix resin, etc. There is a possibility of use.

Claims (4)

A low-temperature curable composition comprising a triaza ring compound represented by the following formula (1), a phenol compound, and a solid epoxy resin having a softening temperature of 60 ° C. or higher as measured by JISK7234.
In the formula (1), R is an organic group having 10 or less carbon atoms.   The low temperature curable composition according to claim 1, wherein R in the formula (1) is a phenyl group.   The low-temperature curable composition according to claim 1, wherein the phenol compound is resorcinol.   R in the above formula (1) is any organic group selected from the group consisting of methyl, propyl, butyl, furfuryl, allyl, and phenyl, and is selected from the group consisting of a cyano group, an isocyanate group, and a vinyl group. The low-temperature curable composition according to claim 1, which is an organic group which may contain a functional group having no active hydrogen.