Low-viscosity hydroxyl-terminated resin with diisocyanate as a core, and preparation method therefor and use thereof

Patent metadata

Field	Value
Publication number	US-11319400-B2
Application number	US-201716475393-A
Country	US
Kind code	B2
Filing date	Nov 14, 2017
Priority date	Jan 3, 2017
Publication date	May 3, 2022
Grant date	May 3, 2022

Abstract

The invention discloses a low-viscosity hydroxyl-terminated resin with diisocyanate as a core, and a preparation method therefor and the use thereof. During preparation, 1 mole of a micromolecular polyol is first modified with 1-3 moles of a monoepoxide so as to obtain a modified polyol; and then 2 moles of the modified polyol is reacted with 1-3 moles of a diisocyanate so as to obtain the hydroxyl-terminated resin. The prepared hydroxyl-terminated resin has the advantages of simple synthesis process, high solid content and low viscosity; the hydroxyl value thereof (at 80% solid mass content) is 140-300 mg KOH/g and the viscosity thereof at 25° C. (at 80% solid mass content) is 300-3000 cp. The hydroxyl-terminated resin is capable of crosslinking with a polyurethane curing agent containing isocyanate groups, and the prepared high solid content dual-component polyurethane coating has a VOC content of less than 380 g/L at the applicable viscosity thereof, and the performance of the coating meets the national standards for solvent based dual-component polyurethane woodenware coatings.

First claim

The invention claimed is:

1. A method for preparing a hydroxyl-terminated resin, characterized by comprising the steps of:
(1) preparation of a modified polyol: adding 1 part by mole of a micromolecular polyol and 0-5 parts by mole of an organic solvent to a reactor, adding a Lewis acid catalyst, dropwise adding 1-3 parts by mole of a monoepoxide at 40-70° C. over 1-5 h, and after completing the dropwise addition, continuing the reaction at 40-70° C. for 4-8 h; when the epoxy value of the reaction system is decreased to less than 1% of the initial mass content of the epoxy value, terminating the reaction, adding distilled water to quench the Lewis acid catalyst, then adding a basic anion exchange resin and continuously stirring for 30-60 min to neutralize the acid catalyst, removing the basic anion exchange resin by filtration, and removing the distilled water and the organic solvent by distilling under reduced pressure at vacuum condition to obtain a polyol modified by the monoepoxide,
wherein the monoepoxide is one or more of butyl glycidyl ether, n-octyl glycidyl ether, isooctyl glycidyl ether, C8-10 alkyl glycidyl ether, decyl glycidyl ether, C10-12 alkyl glycidyl ether, phenyl glycidyl ether, o-tolyl glycidyl ether, p-tert-butylphenyl glycidyl ether, benzyl glycidyl ether, furfuryl glycidyl ether, epichlorohydrin, and glycidyl tertcarbonate; and
(2) preparation of a hydroxyl-terminated resin: adding 2 parts by mole of the modified polyol prepared from step (1) to a reactor, adding an organic solvent in an amount of 15% to 30% by mass percent of the total mass of the reactants, adding 1-1.5 parts by mole of a diisocyanate to the modified polyol at 50-90° C. over 1-3 h, then continuing the reaction at 50-90° C. for 2-6 h, and after the isocyanate group in the reaction system is completely reacted, terminating the reaction and decreasing the temperature to obtain a hydroxyl-terminated resin having a solid mass content of 75% to 90%.

2. The method for preparing a hydroxyl-terminated resin according to claim 1 , characterized in that the micromolecular polyol is ethylene glycol, 1,4-butanediol, 1,6-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, neopentyl glycol, diethylene glycol, 2,4-diethyl-1,5-pentanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, trimethylolpropane, glycerol, diglycerol, ditrimethylolpropane, pentaerythritol, dipentaerythritol, xylitol, erythritol, mannitol, sorbitol, maltitol or lactitol.

3. The method for preparing a hydroxyl-terminated resin according to claim 1 , characterized in that the micromolecular polyol is a polyether polyol, polyester polyol, polycaprolactone polyol or polytetrahydrofuran polyol having an average molecular weight of 200-1000.

4. The method for preparing a hydroxyl-terminated resin according to claim 3 , characterized in that the polyether polyol is one or more of difunctional polyethylene glycol, trifunctional polyether polyol, and tetrafunctional polyether polyol;
the polyester polyol is difunctional polyester polyol;
the polycaprolactone polyol is one or more of difunctional polycaprolactone polyol, trifunctional polycaprolactone polyol, and tetrafunctional polycaprolactone polyol;
the polytetrahydrofuran polyol is difunctional polytetrahydrofuran polyol.

5. The method for preparing a hydroxyl-terminated resin according to claim 1 , characterized in that the Lewis acid catalyst is one or more of boron trifluoride diethyl etherate, boron trifluoride ethanol and boron trifluoride tetrahydrofuran; and the Lewis acid catalyst is added in an amount of 2% to 6% by mole of the micromolecular polyol.

6. The method for preparing a hydroxyl-terminated resin according to claim 1 , characterized in that the basic anion exchange resin is a macroporous basic styrene anion exchange resin.

7. The method for preparing a hydroxyl-terminated resin according to claim 1 , characterized in that the diisocyanate compound is one or more of toluene diisocyanate, diphenylmethane diisocyanate, benzene dimethylene diisocyanate, tetramethylbenzenedimethylene diisocyanate, methylcyclohexyl diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate.

8. The method for preparing a hydroxyl-terminated resin according to claim 1 , characterized in that both the organic solvents in step (1) and step (2) are one or more of ethyl acetate, butyl acetate, dioxane, propylene glycol methyl ether acetate, butanone, methyl isobutyl ketone, methyl isoamyl ketone, cyclohexanone, and isophorone.

9. A hydroxyl-terminated resin, characterized in that it is obtained by the preparation method according to claim 1 , wherein the hydroxyl-terminated resin has a hydroxyl value of 140-300 mg KOH/g at 80% solid mass content, and a viscosity of 300-3000 cp at 25° C. at 80% solid mass content.

10. A coating comprising the hydroxyl-terminated resin of claim 9 and a polyurethane curing agent containing isocyanate groups; the NCO group in the polyurethane curing agent containing isocyanate groups and the OH group in the hydroxyl-terminated resin have a molar ratio of 0.8-1.2:1; and
the polyurethane curing agent containing isocyanate groups is one or more of toluene diisocyanate trimer, toluene diisocyanate/trimethylolpropane adduct, hexamethylene diisocyanate trimer, diphenylmethane diisocyanate monomer and diphenylmethane diisocyanate polymer curing agents.

11. A hydroxyl-terminated resin, characterized in that it is obtained by the preparation method according to claim 2 , wherein the hydroxyl-terminated resin has a hydroxyl value of 140-300 mg KOH/g at 80% solid mass content, and a viscosity of 300-3000 cp at 25° C. at 80% solid mass content.

12. A hydroxyl-terminated resin, characterized in that it is obtained by the preparation method according to claim 3 , wherein the hydroxyl-terminated resin has a hydroxyl value of 140-300 mg KOH/g at 80% solid mass content, and a viscosity of 300-3000 cp at 25° C. at 80% solid mass content.

13. A hydroxyl-terminated resin, characterized in that it is obtained by the preparation method according to claim 4 , wherein the hydroxyl-terminated resin has a hydroxyl value of 140-300 mg KOH/g at 80% solid mass content, and a viscosity of 300-3000 cp at 25° C. at 80% solid mass content.

14. A hydroxyl-terminated resin, characterized in that it is obtained by the preparation method according to claim 5 , wherein the hydroxyl-terminated resin has a hydroxyl value of 140-300 mg KOH/g at 80% solid mass content, and a viscosity of 300-3000 cp at 25° C. at 80% solid mass content.

15. A hydroxyl-terminated resin, characterized in that it is obtained by the preparation method according to claim 6 , wherein the hydroxyl-terminated resin has a hydroxyl value of 140-300 mg KOH/g at 80% solid mass content, and a viscosity of 300-3000 cp at 25° C. at 80% solid mass content.

16. A hydroxyl-terminated resin, characterized in that it is obtained by the preparation method according to claim 7 , wherein the hydroxyl-terminated resin has a hydroxyl value of 140-300 mg KOH/g at 80% solid mass content, and a viscosity of 300-3000 cp at 25° C. at 80% solid mass content.

Assignees

• Univ South China Tech
• Carpoly Chemical Group Co Ltd

Inventors

• Qu Jinqing
• Huang Shan
• Zhu Yan'An
• Chen Ronghua

Classifications

• C08G18/3215 Primary

  containing aromatic groups or benzoquinone groups · CPC title

• C08G18/4829

  Polyethers containing at least three hydroxy groups (C08G18/4833 - C08G18/5096 take precedence) · CPC title

• C08G18/73

  acyclic · CPC title

• C09D175/08

  from polyethers · CPC title

• C08G18/758

  containing two or more cycloaliphatic rings · CPC title