Curable composition

Abstract

The present application relates to a curable composition. The present application provides a curable composition comprising an internal heat source for generating heat by application of an alternate-current magnetic field from the outside, together with a phthalonitrile compound and a curing agent therefor. The curable composition can precisely control the heat generated from the internal heat source according to the strength of the alternate-current magnetic field to precisely control curing conditions of the curable composition.

Claims

1. A curable composition comprising a phthalonitrile compound, a curing agent of the phthalonitrile compound, and magnetic particles having a particle diameter in a range of 20 nm to 300 nm, wherein the phthalonitrile compound is a compound of Formula 1 or a prepolymer comprising the compound of Formula 1: ##STR00007## wherein, R.sub.11 to R.sub.16 are each independently a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryl group, or a substituent of Formula 2 or 3, and at least one of R.sub.11 to R.sub.16 is a substituent of Formula 3: ##STR00008## wherein, L.sub.1 is a single bond, an oxygen atom, a sulfur atom, —S(═O).sub.2—, a carbonyl group, an alkylene group, an alkenylene group, an alkynylene group, —C(═O)—X.sub.3— or —X.sub.3— C(═O)—, wherein X.sub.3 is an oxygen atom, a sulfur atom, —S(═O).sub.2—, an alkylene group, an alkenylene group or an alkynylene group, and R.sub.17 to R.sub.21 are each independently hydrogen, an alkyl group, an alkoxy group, an aryl group or a cyano group, and two or more of R.sub.17 to R.sub.21 are each a cyano group: ##STR00009## wherein, L.sub.2 is a single bond, an oxygen atom, a sulfur atom, —S(═O).sub.2—, a carbonyl group, an alkylene group, an alkenylene group, an alkynylene group, —C(═O)—X.sub.4— or —X.sub.4— C(═O)—, wherein X.sub.4 is an oxygen atom, a sulfur atom, —S(═O).sub.2—, an alkylene group, an alkenylene group or an alkynylene group, and R.sub.22 to R.sub.26 are each independently hydrogen, an alkyl group, an alkoxy group, an aryl group or a substituent of Formula 2, and at least one of R.sub.22 to R.sub.26 is a substituent of Formula 2.

2. The curable composition according to claim 1, wherein the magnetic particles are multi-domain type magnetic particles.

3. The curable composition according to claim 2, wherein the magnetic particles comprise magnetic domains, and wherein the magnetic domains in the magnetic particles have an average size in a range of 10 to 50 nm.

4. The curable composition according to claim 1, wherein the magnetic particles have the particle diameter equal to or greater than Ds satisfying Equation 1: $\begin{array}{cc}{D}_s=2\sqrt{\frac{9A}{{\mu }_0{M}_S^2}\left[\ln \left(\frac{D_s}{a}\right)-1\right]}& \left[\mathrm{Equation}1\right]\end{array}$ wherein, μ.sub.0 is a magnetic permittivity constant in vacuum, M.sub.s is saturation magnetization of the magnetic particles, A is exchange stiffness of the magnetic particles, and a is a lattice constant of the magnetic particles.

5. The curable composition according to claim 1, wherein the magnetic particles have a coercive force in a range of 1 to 200 kOe.

6. The curable composition according to claim 1, wherein the magnetic particles have a saturation magnetization value in a range of 20 to 150 emu/g.

7. The curable composition according to claim 1, wherein the magnetic particles are Formula 6 below:
MX.sub.aO.sub.b  [Formula 6] wherein, M is a metal or a metal oxide, X is Fe, Mn, Co, Ni or Zn, and |a×c|=|b×d| is satisfied, wherein c is a cation charge of X, and d is an anion charge of oxygen.

8. The curable composition according to claim 7, wherein M is Fe, Mn, Mg, Ca, Zn, Cu, Co, Sr, Si, Ni, Ba, Cs, K, Ra, Rb, Be, Li, Y, B or an oxide thereof.

9. The curable composition according to claim 1, further comprising conductive particles having a conductivity at 20° C. of 8 MS/m or more.

10. The curable composition according to claim 9, wherein the conductive particles are nickel, iron, cobalt, silver, copper, gold, aluminum, calcium, tungsten, zinc, lithium, iron, platinum, tin, lead, titanium, manganese, magnesium or chromium particles.

11. The curable composition according to claim 9, wherein the conductive particles have a relative magnetic permeability of 90 or more.

12. The curable composition according to claim 1, wherein a mole ratio of the phthalonitrile compound to the curing agent is about 1:0.02 to 1:1.5.

13. The curable composition according to claim 1, wherein the curing agent of the phthalonitrile compound comprises 1,3-bis(3-aminophenoxy)benzene.

14. The curable composition according to claim 1, further comprising a filler.

15. A method for producing a phthalonitrile resin comprising a step of applying an alternate-current magnetic field to the curable composition of claim 1 to induce a curing reaction between the phthalonitrile compound and the curing agent by heat generated by induction heating of the magnetic particles.

16. The method for producing the phthalonitrile resin according to claim 15, comprising: a first step of applying a first alternate-current magnetic field having a first frequency to the curable composition for a first duration of time; and a second step of applying a second alternate-current magnetic field having a second frequency to the curable composition for a second duration of time, wherein the first frequency is different from the second frequency, and/or the first duration of time is different from the second duration of time.

17. The method for producing the phthalonitrile resin according to claim 15, wherein the phthalonitrile compound in the curable composition is in a prepolymer form.

18. The method for producing the phthalonitrile resin according to claim 15, wherein the alternate-current magnetic field has an intensity in a range of 1 to 500 mTesla during induction heating.

19. The method for producing the phthalonitrile resin according to claim 15, wherein the alternate-current magnetic field has a frequency in a range of 10 kHz to 1,000 kHz during induction heating.

Description

EXAMPLE 1

(1) A compound represented by Formula A was melted on a hot plate at 240° C. for 10 minutes using an aluminum dish. A curing agent (1,3-bis(3-aminophenoxy)benzene) was added to the completely molten compound in a ratio of about 0.15 mol per mol of the above compound, further uniformly mixed on a hot plate at 240° C. for 10 minutes and cooled to prepare a polymerizable composition in the form of a prepolymer.

(2) The prepared prepolymer was pulverized and prepared in the form of a fine powder, followed by mixing a nano-magnetic body at a ratio of about 10 wt %.

(3) As the nano-magnetic body, Mn-ferrite having a saturation magnetization value of about 76 emu/g and a coercive force of about 89 kOe was used, and the particle diameter of the magnetic body was about 100 nm.

(4) The polymerizable composition, in which the nano-magnetic body was mixed, was cured by applying a magnetic field thereto. The curing was performed in two steps, where the magnetic field application conditions and time at each step were summarized in Table 1 below. Also, the application of the magnetic field was performed using an easyheat 830 from Ambrell as a power supply, and a 5-turns pan-cake type coil having a diameter of about 50 mm was used as the working coil.

(5) While the intensity of the alternate-current magnetic field was confirmed by monitoring the temperature inside the coil with a thermal imaging camera, the curing conditions were controlled by the intensity of the applied current and the application time.

(6) ##STR00006##

EXAMPLE 2

(7) The curing was performed in the same manner as in Example 1, except that the curing conditions were adjusted as shown in Table 1 below.

EXAMPLE 3

(8) The curing was performed in the same manner as in Example 1, except that the curing conditions were adjusted as shown in Table 1 below.

EXAMPLE 4

(9) The curing was performed in the same manner as in Example 1, except that the curing conditions were adjusted to three steps as shown in Table 1 below.

EXAMPLE 5

(10) The curing was performed in the same manner as in Example 1, except that Mn—Mg-St-ferrite having a saturation magnetization value of about 55 emu/g, a coercive force of about 73 kOe and a particle diameter of about 100 nm was used as the nano-magnetic body, and the curing conditions were adjusted as shown in Table 1 below.

Comparative Example 1

(11) The compound of Formula A used in Example 1 was melted on a hot plate at 240° C. for 10 minutes using an aluminum dish. A curing agent (1,3-bis(3-aminophenoxy)benzene) was added to the molten compound in a ratio of about 0.15 mol per mol of the above compound. The composition, to which the curing agent was added, was further uniformly mixed on a hot plate at 240° C. for 10 minutes and then cooled to prepare a polymerizable composition in the form of a prepolymer. The composition was cured by holding it in a hot press at 250° C. for 5 minutes and holding it again at 260° C. for 15 minutes.

Comparative Example 2

(12) The polymerizable composition prepared in the same manner as in Comparative Example 1 was cured by holding it in a hot press at 250° C. for 5 minutes and holding it again at 300° C. for 15 minutes.

(13) The measurement results of Examples and Comparative Examples above are shown in Table 1 below.

(14) TABLE-US-00001 TABLE 1 Comparative Example Example 1 2 3 4 5 1 2 Curing Step 1 Intensity  25  25  25  25  25 250° C. 250° C. Conditions Time 5 min 5 min  5 min 5 min  5 min 5 min 5 min Frequency 312 312 312 312 312 — — Step 2 Intensity   37.5   37.5   37.5   37.5   37.5 260° C. 300° C. Time 5 min 10 min 15 min 10 min 15 min 15 min 15 min Frequency 309 309 309 309 309 — — Step 3 Intensity — — — 40 — — — Time — — — 3 min — — — Frequency — — — 308 — — — Total curing time 10 min  15 min  20 min 18 min  20 min 20 min 20 min Cure degree (%) 58% >95% >95% >95% >95% 68% 68% 5% Decomposition temperature (° C.) 484 485 485 485 484 483 485 10% Decomposition temperature (° C.) 526 525 532 527 525 524 527 Intensity: intensity of the applied magnetic field in the case of Examples (unit: mTesla), and application temperature in the case of Comparative Examples Frequency unit: kHz

(15) As confirmed from Table 1, according to the method of the present application, it can be confirmed that a phthalonitrile resin having excellent cure degree and heat resistance characteristics is obtained. Particularly, as can be seen from the comparison of Example 1 with the other Examples and Comparative Examples 1 and 2, according to the conventional method, there is a limit in increasing the cure degree achieved even when the temperature of the curing heat source is increased, while according to the method of the present application, the cure degree can be greatly increased by controlling the curing conditions, whereby it can be confirmed that the freedom degree for controlling the cure degree can be greatly improved.