Curable Composition

Abstract

The present application provides a curable composition having appropriate viscosities and thixotropy before and after curing even if an excessive amount of filler is included and without any sedimentation phenomenon of particles even in long-term storage, wherein the curable composition comprises a polyolefin binder having an acid anhydride unit, a filler and a dispersant, and the dispersant comprise a polymer compound containing a unit of Formula 1 below:

##STR00001## wherein L.sub.1, L.sub.2, p and q are described herein.

Claims

1. A curable composition comprising a polyolefin binder having an acid anhydride unit; a filler; and a dispersant; wherein the dispersant comprises a polymer compound containing a unit of Formula 1 below: ##STR00004## wherein, L.sub.1 is an alkylene group having 3 to 6 carbon atoms, L.sub.2 is a methylene group or an ethylene group, and p/q is a number within a range of 0.5 to 2.

2. The curable composition according to claim 1, wherein the acid anhydride unit is a maleic anhydride unit or a phthalic anhydride unit.

3. The curable composition according to claim 1, wherein the polyolefin binder has an acid value in a range of 50 to 120 mg KOH/g.

4. The curable composition according to claim 1, wherein the polyolefin binder contains one or more units selected from a styrenic unit, a butadiene unit or an isoprene unit.

5. The curable composition according to claim 1, wherein the polyolefin binder has a weight average molecular weight in a range of 3,000 to 30,000 g/mol.

6. The curable composition according to claim 1, wherein the polyolefin binder has a polydispersity index in a range of 2 to 5.

7. The curable composition according to claim 1, wherein the polymer compound containing a unit of Formula 1 has a weight average molecular weight in a range of 5,000 to 40,000 g/mol.

8. The curable composition according to claim 1, wherein the polymer compound containing a unit of Formula 1 has a polydispersity index in a range of 0.8 to 2.

9. The curable composition according to claim 1, wherein the dispersant is included in an amount of 1 to 10 parts by weight relative to 100 parts by weight of the polyolefin binder.

10. The curable composition according to claim 1, wherein the dispersant further comprises an ester compound.

11. The curable composition according to claim 10, wherein the ester compound is one or more selected from the group consisting of alkylene glycol monoalkyl ether acetates, alkylalkoxy propionates, alkylene glycol monoalkyl ether propionates, alkylene glycol diacetates, alkyl lactates and alkyl 2-hydroxyisoalkylates.

12. The curable composition according to claim 1, further comprising a thiol compound.

13. The curable composition according to claim 12, wherein the thiol compound is a thiol substituted with an alkyl group having 1 to 20 carbon atoms.

14. The curable composition according to claim 1, wherein the filler is included in an amount of 25,000 to 45,000 parts by weight relative to 100 parts by weight of the dispersant.

15. The curable composition according to claim 10, wherein the ester compound is included in an amount of 5 to 40 wt % relative to the total weight of the dispersant.

16. The curable composition according to claim 12, wherein the thiol compound is included in an amount within a range of 100 to 500 parts by weight relative to 100 parts by weight of the dispersant.

17. The curable composition according to claim 1, which has a pressing force of 60 gf or less.

18. A curable composition comprising a polyolefin binder having an acid anhydride unit; a filler; and a phosphoric acid-based polymer dispersant, wherein the curable composition has a pressing force of 60 gf or less.

19. A device comprising an exothermic element; and a cooling region, wherein a cured product of the curable composition of claim 1 is included between the exothermic element and the cooling region, and is in thermal contact with the both the exothermic element and the cooling region.

20. The curable composition according to claim 18, wherein the phosphoric acid-based polymer dispersant comprises a polymer compound containing the unit of Formula 1, ##STR00005## wherein, L.sub.1 is an alkylene group having 3 to 6 carbon atoms, L.sub.2 is a methylene group or an ethylene group, and p/q is a number within a range of 0.5 to 2.

Description

DESCRIPTION OF DRAWINGS

[0117] The FIGURE is a graph showing the measured force over time of the curable compositions according to Examples 1 and 2 and Comparative Examples 1 to 4 of the present application.

BEST MODE

[0118] Hereinafter, the present application will be described through Examples and Comparative Examples, but the scope of the present application is not limited by the contents presented below.

[0119] <Method of Measuring Physical Properties>

[0120] (1) Evaluation Method of Long-Term Particle Sedimentation

[0121] A curable composition was placed in a glass vial and left at room temperature and atmospheric pressure for about 60 days. Thereafter, the curable composition in the glass vial was visually observed, and particle sedimentation was evaluated according to the following criteria.

[0122] PASS: In the vial, the curable composition maintains its liquid form without layer separation

[0123] NG: In the vial, layer separation of the curable composition occurs or the curable composition hardens due to curing

[0124] (2) Method of Measuring Pressing Force

[0125] The formed curable composition was placed up to a height of 30 mm from the bottom of a glass vial (about 3 cm in diameter and about 10 cm in height) and left at room temperature for about 60 days.

[0126] For measurement of the pressing force, a tip detachable to a physical property analyzer (Texture Analyzer, TA) was manufactured. Specifically, the tip is one that a cylinder (part T1) having a diameter of 1 mm and a height of 1 cm and a cylinder (part T3) having a diameter of 3 mm and a height of 3 cm are bonded, which has a total height of 4 cm. The end of the T3 part was connected to a physical property analyzer. Thereafter, the glass vial containing the left curable composition was placed in the measurement space of the physical property analyzer, and the end of the T1 part was placed to face the curable composition contained in the glass vial at a distance of 5 mm, thereby completing the pressing force measurement setup.

[0127] Thereafter, the force applied to the tip was measured by pressing the curable composition contained in the glass vial while lowering the tip at a constant speed of 2 mm/s. At this time, the force applied to the tip and the pressing force were measured over time from when the end of the T1 part began to contact the curable composition until it reached a depth of 20 mm.

Example 1

[0128] A polybutadiene (A, manufacturer: Evonik, product name: polyvest MA75) containing a maleic anhydride unit, a thermally conductive filler (B) and a dispersant (C) were mixed in a weight ratio of 100:1,600:4.8 (A:B:C) to form a curable composition.

[0129] As the polybutadiene (A) containing the maleic anhydride unit, one having an acid value of 70 to 90 mg KOH/g (identified by DIN EN ISO 2114) or so, a weight average molecular weight (M.sub.w) of about 10,200 g/mol or so, an average molecular weight (M.sub.n) of about 3,060 g/mol or so and a polydispersity index (PDI=M.sub.w/M.sub.n) of about 3.32 or so was used.

[0130] In addition, as the thermally conductive filler (B), a mixture of spherical aluminum oxide (B1) having an average particle diameter of about 70 μm, spherical aluminum oxide (B2) having an average particle diameter of about 20 μm and non-spherical aluminum hydroxide (B3) having an average particle diameter of about 1 μm in a weight ratio of 65:20:15 (B1:B2:B3) was used.

[0131] The average particle diameter of the filler mentioned in this specification is a D50 particle diameter, also called a so-called median particle diameter, and is a particle diameter (median diameter) at 50% cumulative of the volume-based cumulative curve of the particle size distribution. Such a particle diameter can be defined as the particle diameter at the point where the particle size distribution is obtained on the basis of the volume and the cumulative value becomes 50% on the cumulative curve with 100% of the total volume. The D50 particle diameter can be measured using Marven's MASTERSIZER 3000 equipment based on ISO-13320, where ethanol has been used as a solvent.

[0132] As the dispersant (C), BYK's DISPERBYK-118 was used. The dispersant had a weight average molecular weight (M.sub.w) of about 16,500 g/mol or so, and a polydispersity index (PDI=M.sub.w/M.sub.n) of about 1.23 or so. Also, in the dispersant, about 20 wt % based on the total weight is made of propyleneglycol monoethyl ether acetate (propyleneglycol monomethyl ether acetate), the remainder is made of a compound containing a unit of Formula 1 which is a copolymerization unit of polypropylene glycol (PPG), polyethylene glycol (PEG) and phosphoric acid (PA).

##STR00003##

[0133] In Formula 1 above, p/q is about 1.

Example 2

[0134] A curable composition was formed in the same manner as in Example 1 above, except that the polybutadiene (A, manufacturer: Evonik, product name: polyvest MA75) containing a maleic anhydride unit, the thermally conductive filler (B) and the dispersant (C) were mixed in a weight ratio of 100:1,600:4.8 (A:B:C) and a thiol compound (D) was further mixed. As the thiol compound (D), 1-dodecanthiol was used, and the content of the added thiol compound (D) was 300 parts by weight relative to 100 parts by weight of the dispersant (C).

Comparative Example 1

[0135] The same polybutadiene (A, manufacturer: Evonik, product name: polyvest MA75) containing a maleic anhydride unit and thermally conductive filler (B) as those of Example 1 above were used, but were mixed in a weight ratio of 100:1,600 (A:B) without using the dispersant (C) to form a curable composition.

Comparative Example 2

[0136] A curable composition was formed in the same manner as in Example 1 above, except that BYK's DISPERBYK-111, a phosphoric acid-based dispersant, was used as the dispersant (C). The DISPERBYK-111 had a weight average molecular weight (M.sub.w) of about 1,750 g/mol or so, and a polydispersity index (PDI=M.sub.w/M.sub.n) of about 1.7 or so.

Comparative Example 3

[0137] A curable composition was formed in the same manner as in Example 1, except that BYK's DISPERBYK-102, a phosphoric acid-based dispersant, was used as the dispersant (C). The DISPERBYK-102 had a lower polarity than DISPERBYK-111 used in Comparative Example 2, a weight average molecular weight (M.sub.w) of about 1,630 g/mol or so, and a polydispersity index (PDI=M.sub.w/M.sub.n) of about 1.46 or so.

Comparative Example 4

[0138] A curable composition was formed in the same manner as in Example 1 above, except that the polybutadiene (A, manufacturer: Evonik, product name: polyvest MA75) containing a maleic anhydride unit, the thermally conductive filler (B) and a thiol compound (D) were mixed in a weight ratio of 100:1,600:4.8 (A:B:D). As the thiol compound (D), 1-dodecanthiol was used.

[0139] The physical property measurement results of Examples and Comparative Examples above were shown in the following table.

TABLE-US-00001 TABLE 1 Long-term sedimentation Pressing Classification evaluation force (gf) Example 1 X 46.8 Example 2 X 27.7 Comparative Example 1 ◯ 67.0 Comparative Example 2 ◯ 219.7 Comparative Example 3 ◯ 184.8 Comparative Example 4 ◯ 65.9

[0140] As shown in Table 1, it can be seen that in the evaluation of long-term particle sedimentation, the curable compositions according to Examples 1 and 2 have not settled even after being left for a long time, and it can be seen therefrom that the storage stability for a long time is excellent.

[0141] On the other hand, in the evaluation of long-term particle sedimentation, the curable compositions according to Comparative Examples 1 to 4 caused layer separation by settling the particles down in the vial.

[0142] Here, as shown in Table 1, the pressing force of the curable composition according to Example 1 was 46.8 gf and the pressing force of the curable composition according to Example 2 was 27.7 gf, and it can be seen that both have not caused particle sedimentation even when left for a long time.

[0143] On the other hand, the pressing force of the curable compositions according to Comparative Examples 1 to 4 were 67.0 gf, 219.7 gf, 184.8 gf, and 65.9 gf, respectively, and it can be seen that all have caused particle sedimentation when left for a long time.

[0144] The FIG. 1s a graph showing the measured force over time of the curable compositions according to Examples 1 and 2 and Comparative Examples 1 to 4 of the present application. In the FIGURE, the portion where the pressing force rapidly increases over time means the time when the T3 part of the tip is in contact with the curable composition.

[0145] As shown in the FIGURE, it can be seen that the maximum forces for the curable compositions according to Examples 1 and 2 and Comparative Examples 1 to 4 are as shown in Table 1 above.

[0146] Here, the constitutions and features of the present application have been described based on Examples according to the present application, but the present application is not limited thereto, and it is apparent to those skilled in the technical field to which the present application belongs that various changes or modifications can be made within the ideas and scope of the present application, and thus it is pointed out that such changes or modifications fall within the scope of the appended claims.