Poly-rotaxane compound, photocurable coating composition, and coating film

Abstract

The present invention relates to a novel polyrotaxane compound having a specific chemical structure, a photocurable coating composition that may provide a coating material having excellent mechanical properties such as scratch resistance, chemical resistance, abrasion resistance, and the like, and excellent self-healing capability, and a coating film obtained from the photocurable coating composition.

Claims

1. A polyrotaxane compound comprising: a macrocycle to which a lactone-based compound is bonded; a linear molecule penetrating the macrocycle; and blocking groups arranged at both ends of the linear molecule and preventing the macrocycle from escaping, wherein a final substitution rate at the end of the lactone-based compound bonded to the macrocycle of the polyrotaxane compound is 40 mol % to 70 mol %.

2. The polyrotaxane compound according to claim 1, wherein the final substitution rate at the end of the lactone-based compound bonded to the macrocycle of the polyrotaxane compound is 45 mol % to 65 mol %.

3. The polyrotaxane compound according to claim 1, wherein the macrocycle includes at least one selected from the group consisting of -cyclodextrin, -cyclodextrin, and -cyclodextrin.

4. The polyrotaxane compound according to claim 1, wherein the lactone-based compound is bonded to the macrocycle by a direct bond or a C1-10 linear or branched oxyalkylene group.

5. The polyrotaxane compound according to claim 1, wherein a residue of the lactone-based compound includes a functional group of the following Chemical Formula 1: ##STR00003## wherein, in Chemical Formula 1, m is an integer of from 2 to 11, and n is an integer of from 1 to 20.

6. The polyrotaxane compound according to claim 1, wherein a (meth)acrylate-based compound is substituted to the end of the lactone-based compound through a direct bond, a urethane bond, an ether bond, a thioester bond, or an ester bond.

7. The polyrotaxane compound according to claim 6, wherein the (meth)acrylate-based compound includes a functional group of the following Chemical Formula 2: ##STR00004## wherein, in Chemical Formula 2, R.sub.1 is hydrogen or a methyl, and R.sub.2 is a C1-12 linear or branched alkylene group, a C4-20 cycloalkylene group, or a C6-20 arylene group.

8. The polyrotaxane compound according to claim 1, wherein the linear molecule is a polyoxyalkylene-based compound or a polylactone-based compound.

9. The polyrotaxane compound according to claim 1, wherein the linear molecule has a weight average molecular weight of 1000 to 50,000.

10. The polyrotaxane compound according to claim 1, wherein the blocking group includes at least one functional group selected from the group consisting of dinitrophenyl, cyclodextrin, adamantane, trityl, fluorescein, and pyrene groups.

11. The polyrotaxane compound according to claim 1, wherein the polyrotaxane compound has a weight average molecular weight of 100,000 to 800,000.

12. A photocurable coating composition comprising: the polyrotaxane compound of claim 1; a polymer resin or a precursor thereof; and a photoinitiator.

13. The photocurable coating composition according to claim 12, wherein the final substitution rate at the end of the lactone-based compound bonded to the macrocycle of the polyrotaxane compound is 45 mol % to 65 mol %.

14. The photocurable coating composition according to claim 12, wherein the polymer resin is selected from the group consisting of a polysiloxane-based resin, a (meth)acrylate-based resin, and a urethane(meth)acrylate-based resin, a mixture thereof, and a copolymer thereof.

15. The photocurable coating composition according to claim 12, wherein the precursor of the polymer resin includes monomers or oligomers including at least one functional group selected from the group consisting of (meth)acrylate, vinyl, siloxane, epoxy, and urethane groups.

16. The photocurable coating composition according to claim 12, wherein the photoinitiator includes at least one compound selected from the group consisting of an acetophenone-based compound, a biimidazole-based compound, a triazine-based compound, and an oxime-based compound.

17. The photocurable coating composition according to claim 12, comprising: 1 to 95 wt % of the polyrotaxane compound; 1 to 95 wt % of the polymer resin or a precursor thereof; and 0.01 to 10 wt % of the photoinitiator.

18. The photocurable coating composition according to claim 12, further comprising an organic solvent.

19. A coating film comprising a photocured product of the photocurable coating composition of claim 12.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows 1H NMR data of a polyrotaxane polymer [A1000] that is used as a reactant in Example 1.

(2) FIG. 2 shows a gCOSY NMR spectrum confirming the structure of caprolactone included in the polyrotaxane polymer [A1000] that is used as a reactant in Example 1.

(3) FIG. 3 shows one example of 1H NMR data of polyrotaxane including a macrocycle to which a lactone-based compound including a (meth)acrylate-based compound introduced at the end is bonded.

DETAILS FOR PRACTICING THE INVENTION

(4) Hereinafter, the present invention will be explained in detail with reference to the following examples. However, these examples are only to illustrate the invention, and the scope of the invention is not limited thereto.

Examples 1 and 2 and Comparative Example 1: Synthesis of Polyrotaxane

Example 1

(5) 50 g of a caprolactone-grafted polyrotaxane polymer [A1000, Advanced Soft Material Inc.] was introduced into a reactor, and then 4.53 g of Karenz-AOI [2-acryloylethyl isocyanate, Showadenko K.K.], 20 mg of dibutyltin dilaurate [DBTDL, Merck & Co, Inc.], 110 mg of hydroquinone monomethylene ether, and 315 g of methylethylketone were added thereto and reacted at 70 C. for 5 hours, to obtain a polyrotaxane polymer liquid including cyclodextrin to which a polylactone-based compound having an acrylate-based compound introduced at the end is bonded as a macrocycle (solid content: 15%).

(6) The polyrotaxane polymer liquid was dripped into an n-hexane solvent to precipitate a polymer, which was filtered to obtain a white solid polymer (weight average molecular weight: 500,000).

(7) 1H NMR data of the polyrotaxane polymer [A1000] that was used as a reactant is shown in FIG. 1, and the structure of the caprolactone bonded to the macrocycle of polyrotaxane was confirmed through the gCOSY NMR spectrum of FIG. 2.

(8) Further, 1H NMR of polyrotaxane included in the finally obtained polyrotaxane polymer liquid has a shape as shown in FIG. 3 [peak intensity and the like may be different].

(9) The number of caprolactone repeating units in the macrocycle of polyrotaxane (m+n in FIG. 1) was confirmed to be 8.05 through NMR data of FIG. 2, and it can be seen that if the number of repeating units is 8, the 7.sup.th peak of FIG. 3 has intensity of 16.00 (2H*8).

(10) If the end of the caprolactone repeat unit is 100% substituted by OH, the 1.sup.st peak of FIG. 3 relating to acrylate functional groups should be 4.00 (2H*2). Thus, the end substitution rate of a lactone-based compound bonded to the macrocycle of polyrotaxane may be calculated by comparing with practically measured 1H NMR values.

(11) The substitution rate of the finally obtained polyrotaxane polymer liquid (solid content: 15%) was 46.8%.

Example 2

(12) 50 g of a caprolactone-grafted polyrotaxane polymer [A1000, Advanced Soft Material Inc.] was introduced into a reactor, and then 9.06 g of Karenz-AOI [2-acryloylethyl isocyanate, Showadenko K.K.], 20 mg of dibutyltin dilaurate [DBTDL, Merck & Co, Inc.], 110 mg of hydroquinone monomethylene ether, and 315 g of methylethylketone were added thereto and reacted at 70 C. for 5 hours, to obtain a polyrotaxane polymer liquid including cyclodextrin to which a polylactone-based compound having an acrylate-based compound introduced at the end is bonded as a macrocycle (solid content: 15%).

(13) The polyrotaxane polymer liquid was dripped into an n-hexane solvent to precipitate a polymer, which was filtered to obtain a white solid polymer (weight average molecular weight: 500,000).

(14) 1H NMR data of the polyrotaxane polymer [A1000] that was used as a reactant is as shown in FIG. 1, and the structure of the caprolactone bonded to the macrocycle of polyrotaxane was confirmed through the gCOSY NMR spectrum of FIG. 2.

(15) Further, the 1H NMR of polyrotaxane included in the finally obtained polyrotaxane polymer liquid has a shape as shown in FIG. 3 [peak intensity and the like may be different].

(16) The number of caprolactone repeating units in the macrocycle of polyrotaxane (m+n in FIG. 1) was confirmed to be 8.05 through NMR data of FIG. 2, and it can be seen that if the number of repeating units is 8, the 7.sup.th peak of FIG. 3 has intensity of 16.00 (2H*8).

(17) If the end of the caprolactone repeating units is 100% substituted by OH, the 1.sup.st peak of FIG. 3 relating to acrylate functional groups should be 4.00 (2H*2). Thus, the end substitution rate of a lactone-based compound bonded to the macrocycle of polyrotaxane may be calculated by comparing with practically measured 1H NMR values.

(18) The substitution rate of the finally obtained polyrotaxane polymer liquid (solid content: 15%) was 60.0%.

Comparative Example 1

(19) 50 g of caprolactone-grafted polyrotaxane polymer [A1000, Advanced Soft Material Inc.] was introduced into a reactor, and then 13.58 g of Karenz-AOI [2-acryloylethyl isocyanate, Showadenko K.K.], 20 mg of dibutyltin dilaurate [DBTDL, Merck & Co, Inc.], 110 mg of hydroquinone monomethylene ether, and 315 g of methylethylketone were added thereto and reacted at 70 C. for 5 hours, to obtain a polyrotaxane polymer liquid including cyclodextrin to which a polylactone-based compound having an acrylate-based compound introduced at the end is bonded as a macrocycle (solid content: 15%).

(20) It was confirmed by the same method as Examples 1 and 2 that 1H NMR of the polyrotaxane included in the finally obtained polyrotaxane polymer liquid has a shape as shown in FIG. 3 [peak intensity and the like may be different].

(21) As the result of calculating the end substitution rate of the lactone-based compound bonded to the macrocycle of polyrotaxane by the same method as Examples 1 and 2, the substitution rate of the finally obtained polyrotaxane polymer liquid (solid content: 15%) was close to about 100%.

Examples 3 to 4 and Comparative Example 2: Preparation of Photocurable Coating Composition and Coating Film

Example 3

(22) (1) Preparation of Photocurable Coating Composition

(23) 100 parts by weight of the polyrotaxane obtained in Example 1, 15 parts by weight of UA-200PA (multifunctional urethane acrylate, Shin-Nakamura Chemical Co., Ltd.), 40 parts by weight of PU-3400 (multifunctional urethane acrylate, Miwon Chemicals Co., Ltd.), 10 parts by weight of Miramer SIU2400 (multifunctional urethane acrylate, Miwon Chemicals Co., Ltd.), 15 parts by weight of Estane-5778 (polyester-based polyurethane, Lubrizol Corporation), 1.5 parts by weight of photoinitiator Irgacure-184, 1.55 parts by weight of photoinitiator Irgacure-907, 12.5 parts by weight of isopropyl alcohol (IPA), and 12.5 parts by weight of ethylcellusolve were mixed to prepared a photocurable coating composition.

(24) (2) Preparation of Coating Film

(25) The photocurable coating composition was coated on a PET film (thickness 188 m) using a wire bar (No. 70). Further, the coated product was dried at 90 C. for 2 minutes, and UV was irradiated for 5 seconds at 200 mJ/cm.sup.2 to prepare a film with a thickness of 30 m.

Example 4: Preparation of Photocurable Coating Composition

(26) (1) Preparation of Photocurable Coating Composition

(27) A photocurable coating composition was prepared by the same method as Example 3, except using the polyrotaxane obtained in Example 2.

(28) (2) Preparation of Coating Film

(29) The photocurable coating composition was coated on a PET film (thickness 188 m) using a wire bar (No. 70). And, the coated product was dried at 90 C. for 2 minutes, and then, UV was irradiated for 5 seconds at 200 mJ/cm.sup.2 to prepare a film with a thickness of 30 m.

Comparative Example 2

(30) (1) Preparation of Photocurable Coating Composition

(31) A photocurable coating composition was prepared by the same method as Example 3, except using the polyrotaxane obtained in Comparative Example 1.

(32) (2) Preparation of Coating Film

(33) The photocurable coating composition was coated on a PET film (thickness 188 m) using a wire bar (No. 70). And, the coated product was dried at 90 C. for 2 minutes, and then, UV was irradiated for 5 seconds at 200 mJ/cm.sup.2 to prepare a film with a thickness of 30 m.

Experimental Example: Evaluation of Properties of Coating Film

(34) The properties of the coating films obtained in Examples 3 and 4 and Comparative Example 2 were evaluated as follows.

(35) 1. Optical properties: Light transmittance and haze were measured using a haze meter (Murakami Co. Ltd HR-10).

(36) 2. Self-healing capability: A time to recover from a scratch after rubbing the surface of a coating film with a copper brush at a load of 500 g was measured.

(37) 3. Measurement of Scratch Resistance

(38) A constant load was applied to steel wool to cause scratches, and then the surface of a coating film was observed with the naked eye.

(39) 4. Mandrel Test

(40) The coating films obtained in the examples and comparative examples were respectively wound 180 around cylindrical mandrels having different thicknesses and maintained for 1 second, and then crack generation was observed with the naked eye, and a time when cracks are not generated was confirmed while lowering a value of the cylindrical mandrels.

(41) 5. Hardness: Pencil hardness was measured at a load of 500 g.

(42) The measurement results are described in the following Table 1.

(43) TABLE-US-00001 TABLE 1 Comparative Example 3 Example 4 Example 2 Transmittance (%)/ 92.3/0.9 92.1/0.9 99.3/1.0 Haze (%) Self-healing Within 5 seconds Within 5 seconds 45 seconds (500 g load) Steel wool/ Good Good Good 200 g load (no damage) (no damage) (no damage) Steel wool/ Good Good Good 300 g load (no damage) (no damage) (no damage) Pencil hardness F H H Mandrel test () 4 6 24

(44) As shown in the Table 1, it was confirmed that the coating films prepared in Examples 3 and 4 exhibit low haze while having high transmittance compared to the coating film obtained in Comparative Example 2, thus having an excellent appearance property.

(45) Further, in the experimental example relating to self-healing capability for recovery of the surface within 1 minute after being rubbed with a copper brush, it was also confirmed that the coating films prepared in Examples 3 and 4 have excellent self-healing capability compared to the coating film obtained in Comparative Example 2.

(46) Further, it was confirmed that the coating films prepared in Examples 3 and 4 generate little scratching even under a load of 200 g or 300 g with steel wool, thus having excellent scratch resistance.

(47) It was also confirmed that the coating films prepared in Examples 3 and 4 do not generate cracks even with a cylindrical mandrel having lower value, thus having higher elasticity and durability compared to the comparative example.