THERMOSETTING COMPOSITION

Abstract

The present invention relates to a thermosetting composition and a method for curing the same, and provides a thermosetting composition capable of realizing uniform curing physical properties of a cured product.

Claims

1. A thermosetting composition comprising: magnetic particles having two or more magnetic domains, wherein the magnetic domains are irregularly arranged when an external magnetic field is absent and are magnetized by an external alternating magnetic field; and a thermosetting resin.

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

3. The thermosetting composition according to claim 1, wherein the magnetic particles have a saturation magnetization value at 25 C. in a range of 20 to 150 emu/g.

4. The thermosetting composition according to claim 1, wherein the magnetic particles have an average particle diameter in a range of 20 to 300 nm.

5. The thermosetting composition according to claim 1, wherein the magnetic domains have an average size in a range of 10 to 50 nm.

6. The thermosetting composition according to claim 1, wherein the magnetic particles comprise a compound of Formula 1:
MX.sub.aO.sub.b[Formula 1] wherein M is a metal or a metal oxide, X comprises Fe, Mn, Co, Ni or Zn, and |ac|=|bd| is satisfied, where c is a cation charge of X, and d is an anion charge of oxygen.

7. The thermosetting composition according to claim 6, 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.

8. The thermosetting composition according to claim 6, wherein the magnetic particles comprise a mixture of compounds of Formula 1 or a compound comprising the compound of Formula 1 doped with an inorganic substance.

9. The thermosetting composition according to claim 1, wherein the thermosetting composition comprises the magnetic particles in an amount of 0.01 to 25 parts by weight relative to 100 parts by weight of the thermosetting resin.

10. The thermosetting composition according to claim 1, wherein the magnetic particles form magnetic clusters.

11. The thermosetting composition according to claim 1, wherein the magnetic particles are vibrated by magnetization reversal.

12. The thermosetting composition according to claim 1, wherein the thermosetting resin comprises at least one thermosetting functional group.

13. The thermosetting composition according to claim 12, wherein the thermosetting functional group comprises an epoxy group, a glycidyl group, an isocyanate group, a hydroxy group, a carboxyl group or an amide group.

14. The thermosetting composition according to claim 1, further comprising a thermosetting agent.

15. The thermosetting composition according to claim 1, further comprising a filler.

16. The thermosetting composition according to claim 1, further comprising a dispersant.

17. A method for curing the thermosetting composition of claim 1, the method comprising a step of applying a magnetic field to the thermosetting composition of claim 1.

18. The method for curing the thermosetting composition according to claim 17, wherein the step of applying the magnetic field comprises applying the magnetic field with a current of 50 A to 500 A for 20 seconds to 60 minutes at a frequency of 100 kHz to 1 GHz.

19. The method for curing the thermosetting composition according to claim 17, wherein the step of applying the magnetic field comprises performing a multi-profile method that comprises sequentially applying at least two magnetic fields.

20. The method for curing the thermosetting composition according to claim 19, wherein the multi-profile method comprises: a first step of applying a first magnetic field with a current of 10 A to 120 A for 20 seconds to 10 minutes; a second step of applying a second magnetic field with a current of 80 A to 150 A for 20 seconds to 10 minutes; and a third step of applying a third magnetic field with a current of 85 A to 500 A for 5 seconds to 5 minutes, wherein the first, second, and third magnetic fields are applied at a frequency of 100 kHz to 1 GHz.

21. The method for curing the thermosetting composition according to claim 17, wherein the thermosetting composition comprises a first portion and a second portion, and the step of applying the magnetic field comprises applying a first magnetic field to the first portion of the thermosetting composition, and wherein the method further comprises adding the second portion of the thermosetting composition onto the first portion of the thermosetting composition after applying the first magnetic field.

22. The method for curing the thermosetting composition according to claim 21, further comprising applying a second magnetic field after adding the second portion of the thermosetting composition, wherein the first magnetic field is applied with a first current value a1, the second magnetic field is applied with a second current value a2, and a ratio a1/a2 is in a range of 1.01 to 3.0.

23. The method for curing the thermosetting composition according to claim 17, wherein the step of applying the magnetic field comprises decreasing a current value or a magnetic field application time as a volume of the thermosetting composition increases.

24. A cured product comprising a cured form of the thermosetting composition of claim 1.

Description

BEST MODE

[0052] Hereinafter, the present invention will be described in more detail with reference to Example complying with the present invention and Comparative Examples not complying with the present invention, but the scope of the present invention is not limited by the following examples.

Example 1

[0053] Soft magnetic (soft type) FeOFe.sub.2O.sub.3 particles (multi-magnetic domains, average particle diameter about 50 nm: measured by Field Emission Scanning Electron Microscope (using DLS)) as magnetic particles, KSR-177 from Kukdo Chemical as an epoxy resin, and SI-B2 A curing agent from Samshin Hwasung as a curing agent were each mixed at a weight ratio of 5:94:1 (FeOFe.sub.2O.sub.3: KSR-177: SI-B2 A) to prepare a resin composition.

[0054] Immediately after laminating it on a support through a nozzle in a feeding device, a magnetic field was applied thereto with a current value of 100 A for 1 minute in an external alternate-current magnetic field generator. The magnetic field was applied by introducing the composition into a sample vial in a solenoid coil (3 turns, OD 50 mm, ID 35 mm) and adjusting the current value and time of the magnetic field generator (Easyheat from Ambrell). The resin composition was thermally cured with vibrational heat generated through application of the magnetic field to form a cured product.

Example 2

[0055] A resin composition was prepared and a cured product was formed, in the same manner as in Example 1, except that the particle diameter of the magnetic particles was 100 nm.

Example 3

[0056] A resin composition was prepared and a cured product was formed, in the same manner as in Example 1, except that the contents of the magnetic particles, the resin and the curing agent were each included at a weight ratio of 10:90:5.

Example 4

[0057] A resin composition was prepared and a cured product was formed, in the same manner as in Example 1, except that the particle diameter of the magnetic particles was 200 nm.

Example 5

[0058] A resin composition was prepared and a cured product was formed, in the same manner as in Example 2, except that MnOFe.sub.2O.sub.3 particles (multi-magnetic domains, average particle diameter about 100 nm: measured by Field Emission Scanning Electron Microscope (using DLS)) were used as the magnetic particles.

Example 6

[0059] A resin composition was prepared and a cured product was formed, in the same manner as in Example 2, except that a magnetic field was applied for 3 minutes with a current value of 200 A using a pancake type (3 turns, diameter 50 mm) upon applying the magnetic field.

Example 7

[0060] A resin composition was prepared and a cured product was formed, in the same manner as in Example 2, except that a magnetic field was applied for 3 minutes with a current value of 200 A using Helmholtz coils (3 turns, diameter 20 mm) upon applying the magnetic field.

Example 8

[0061] A resin composition was prepared and a cured product was formed, in the same manner as in Example 2, except that a magnetic field having a current value of 100 A was applied for 45 seconds, a magnetic field having a current value of 120 A was applied for 10 seconds and a magnetic field having a current value of 150 A was applied for 5 seconds through a multi-profile method.

Example 9

[0062] A resin composition was prepared as in Example 2, and a cured product was formed in the following manner. Specifically, the resin composition is primarily applied on a support and cured by applying a magnetic field having a current value of 100 A for 45 seconds, a magnetic field having a current value of 120 A for 10 seconds and a magnetic field having a current value of 150 A for 5 seconds through the multi-profile method of the magnetic fields. Thereafter, in order to further laminate the resin composition thereon, a laminate was formed by applying a magnetic field having a current value of 84 A for 45 seconds, a magnetic field having a current value of 100 A for 10 seconds and a magnetic field having a current value of 125 A for 5 seconds after the secondary application.

Example 10

[0063] A resin composition was prepared as in Example 2, and a cured product was formed in the following method. Specifically, the resin composition is primarily applied on a support and cured through a multi-profile method of a magnetic field in which a magnetic field having a current value of 100 A is applied for 45 seconds, a magnetic field having a current value of 120 A is applied for 10 seconds and a magnetic field having a current value of 150 A is applied for 5 seconds. Thereafter, in order to further laminate the resin composition thereon, a multi-layered laminate was formed by applying a magnetic field having a current value of 84 A for 45 seconds, a magnetic field having a current value of 100 A for 10 seconds and a magnetic field having a current value of 125 A for 5 seconds after the secondary application, applying a magnetic field having a current value of 70 A for 40 seconds, a magnetic field having a current value of 90 A for 10 seconds and a magnetic field having a current value of 100 A for 5 seconds after the tertiary application, and applying a magnetic field having a current of 70 A for 30 seconds, a magnetic field having a current value of 85 A for 10 seconds and a magnetic field having a current value of 90 A for 5 seconds after the quaternary application.

Example 11

[0064] The primary application and curing were performed in the same manner as in Example 9. Thereafter, a laminate was formed by applying a magnetic field having a current value of 100 A for 45 seconds, a magnetic field having a current value of 120 A for 10 seconds and a magnetic field having a current value of 150 A for 5 seconds after the secondary application laminated thereon.

Example 12

[0065] The primary application and curing were performed in the same manner as in Example 10. Thereafter, for the secondary to quaternary applications and the magnetic field applications, a method of applying a magnetic field having a current value of 100 A for 45 seconds, a magnetic field having a current value of 120 A for 10 seconds and a magnetic field having a current value of 150 A for 5 seconds through the multi-profile method of the magnetic fields was performed, so that the same method was repeated four times to form a multi-layered laminate.

Comparative Example 1

[0066] Ferromagnetic (hard type) FeOFe.sub.2O.sub.3 particles (single-magnetic domains, average particle diameter about 100 nm) as magnetic particles, a bisphenol-based epoxy resin and the curing agent were each mixed at a weight ratio of 5:95:5 to prepare a resin composition.

[0067] Immediately after laminating it on a support through a nozzle in a feeding device, a magnetic field was applied thereto with a current value of 100 A for 10 minutes in an external alternate-current magnetic field generator. The magnetic field was applied by introducing the composition into a sample vial in a solenoid coil (3 turns, OD 50 mm, ID 35 mm) and adjusting the current value and time of the magnetic field generator (Easyheat from Ambrell). The resin composition was thermally cured with vibrational heat generated through application of the magnetic field to form a cured product.

Comparative Example 2

[0068] A resin composition was prepared and a cured product was formed, in the same manner as in Comparative Example 1, except that ferromagnetic (hard type) Fe particles (single-magnetic domain, average particle diameter about 50 nm) were used as the magnetic particles and the contents of the magnetic particles, the resin and the curing agent were each included in a weight ratio of 5:90:5.

Comparative Example 3

[0069] A resin composition was prepared and a cured product was formed, in the same manner as in Comparative Example 1, except that ferromagnetic (hard type) StOFe.sub.2O.sub.3 particles (single-magnetic domain, average particle diameter about 100 nm) were used as the magnetic particles and the contents of the magnetic particles, the resin and the curing agent were each included in a weight ratio of 5:90:5.

Experimental Example 1Measurement of Coercive Force and Saturation Magnetization Value (Ms) of Magnetic Particles

[0070] Coercive force and saturation magnetization Ms were measured by placing the magnetic particles dried at room temperature in a vibrating sample magnetometer (SQUID, measured by Korea Basic Science Institute) and using an HS curve (VSM curve) at +1 Tesla as an external magnetic field.

Experimental Example 2Measurement of Temperature of Composition after Curing

[0071] In Examples and Comparative Examples, immediately after the magnetic field application, a temperature inside the three-dimensional shape is confirmed by sticking a thermocouple therein.

Experimental Example 3Measurement of Cure Degree

[0072] (1) Visual Touch Sense

[0073] After curing the composition and cooling the cured product, the curing was confirmed by checking whether or not the cured product flowed when it was turned over, and then checking the degree of pressing of the cured product with a metal spatula. Here, it was classified as O when there was no flowability and the cured product was not pressed at all, as when there was no flowability and the cured product was not pressed at all, but when the cured product was partially broken from the desired shape, and as X when there was flowability and the cured product was pressed.

[0074] (2) IR Data

[0075] The degree of curing is determined by using the ratio of the intensity (about 900 cm.sup.1) of the epoxy group and the intensity (about 1500 cm.sup.1) of the phenyl group before and after thermal curing of the composition and calculating it as a conversion ratio (%).

[0076] (3) DSC Data

[0077] The degree of curing is determined by measuring the amount of remaining heat (J/g) in the endothermic peak section, generated when the sample heat-cured after the magnetic field application is raised to a temperature of 300 C. at a temperature rise rate of 10 C./min by a cut DSC.

TABLE-US-00001 TABLE 1 Measurement of Cure Degree Coercive Temperature Visual Ms Force after Curing Touch (emu/g) (kOe) ( C.) Sense IR DSC Example 1 72 70 not O 49% 12.3 J/g Example 2 74 80 measurable O 53% 5.2 J/g Example 3 74 80 O 56% 3.0 J/g Example 4 82 92 O 47% 8.8 J/g Example 5 80 94 O 54% 4.3 J/g Example 6 74 80 O 51% 5.8 J/g Example 7 74 80 O 53% 5.7 J/g Example 8 74 80 O 57% 2.9 J/g Example 9 74 80 O Example 10 74 80 O Example 11 74 80 Example 12 74 80 Comparative Example 1 218 2000 32 X not measurable not measurable Comparative Example 2 154 294 26 X not measurable not measurable Comparative Example 3 48 1500 41 X not measurable not measurable

[0078] In the case of Examples 1 to 12, the cured products hardened hardly, so that the temperature measurement using the thermocouple was impossible. In the case of Comparative Examples 1 to 3, it can be confirmed that they generate heat by an eddy current as a technique by electromagnetic induction, which generate heat by hysteresis loss of the magnetic body particles. Accordingly, Comparative Examples 1 to 3 did not satisfy the desired curing physical properties of the cured product.