SYNTHESIS OF CYANURATE AND MULTIFUNCTIONAL ALCOHOL-BASED POLYETHER ACRYLATE FOR UV CURABLE MATERIALS

Abstract

Polyether (meth)acrylates based on cyanuric acid or substituted cyanuric acid and multifunctional alcohol, which optionally include triethanolamine units, have wide applications in UV curable adhesives, coatings, inks, sealants, paints or 3D printing. These polyether acrylates have rigid cyanurate structure endowing the material with extra strength and thermal stability. Furthermore, triethanolamine unit, when present, endows the material with anti-oxygen inhibition property in UV curing process. These polyether (meth)acrylates have low viscosity and high reactivity towards UV curing. The cured resins have high resilience and strength. The process of making the polyether (meth)acrylates includes the synthesis of trifunctional polyether polyols through controlled polymerization of propylene oxide using multifunctional alcohol (such as glycerol and sucrose), cyanuric acid or substituted cyanuric acid, and optionally triethanolamine, in the presence of a catalyst, followed by the synthesis of polyether (meth)acrylates through transesterification or through direct esterification of the trifunctional polyether polyols.

Claims

1. A multifunctional polyether polyol which is a polymerization product of: cyanuric acid or substituted cyanuric acid, multifunctional alcohol, and propylene oxide.

2. The polyether polyol according to claim 1, wherein the substituted cyanuric acid is 1,3,5-Tris(2-hydroxyethyl)cyanuric acid.

3. The polyether polyol according to claim 1, having the following general formula: ##STR00003## wherein each of x, y, and z is independently 1 to 20.

4. The polyether polyol according to claim 1, wherein the polymerization product further includes triethanolamine units.

5. The polyether polyol according to claim 1, having a molecular weight of 300-2000 g/mol.

6. A polymer which is an esterified product of (i) the polyether polyol according to a claim 1; and (ii) any one or a combination of acrylic acid, methacrylic acid, acrylate and methacrylate.

7. The polymer according to claim 6, wherein the acrylate is ethyl acrylate or methyl acrylate, and the methacrylate is methyl methacrylate or ethyl methacrylate.

8. A UV curable composition comprising the polymer of claim 6.

9. The composition according to claim 8, for use in any one of coatings, adhesives, paints, printing inks, and 3D printing.

10. A method of preparing a trifunctional polyether polyol, the method comprising: mixing monomers in a reactor in the presence of a catalyst to obtain a mixture of the monomers, wherein the monomers in the mixture comprise cyanuric acid or substituted cyanuric acid, multifunctional alcohol, and propylene oxide; and polymerizing the monomers in the reactor to produce the trifunctional polyether polyol.

11. The method according to claim 10, wherein the monomers further comprise triethanolamine.

12. The method according to claim 11, wherein the cyanuric acid or the substituted cyanuric acid is in the amount of 0-60 mol %, and the triethanolamine is in the amount of 0-20 mol %.

13. The method according to claim 10, wherein the multifunctional alcohol is glycerol or sucrose.

14. The method according to claim 10, wherein the catalyst is an alkaline catalyst.

15. The method according to claim 14, wherein the alkaline catalyst is potassium hydroxide or sodium hydroxide.

16. The method according to claim 10, wherein the catalyst is present in a concentration of about 0.1-5 mol % of hydroxyl groups.

17. The method according to claim 16, wherein the concentration of the catalyst is about 0.2-3 mol % of hydroxyl groups.

18. A method of preparing a polyether polyol (meth)acrylate comprising: adding the multifunctional polyether polyol according to claim 1 into a reactor; and reacting the trifunctional polyether polyol with an esterification agent in the presence of a catalyst, wherein the esterification agent is selected from the group consisting of acrylic acid, methacrylic acid, low alcohol acrylate, and low alcohol methacrylate.

19. The method according to claim 18, wherein the polyether polyol is glycerol isocyanurate poly(propylene oxide) polyether polyol, glycerol-triethanolamine-isocyanurate poly(propylene oxide) polyether polyols, sucrose-glycerol poly(propylene oxide) polyether polyols, sucrose-glycerol-triethanolamine poly(propylene oxide) polyether polyols.

20. The method according to claim 18, wherein the esterification agent used in the reacting step is low alcohol acrylate or low alcohol methacrylate, selected from the group consisting of methyl acrylate, ethyl acrylate, methyl methacrylate and ethyl methacrylate.

21. The method according to claim 20, wherein the catalyst is titanium tetrachloride (TiCl.sub.4) or titanium tetraiosproppoxide (TiTIP).

22. The method according to claim 21, wherein TiCl.sub.4 is in a concentration of about 0.1-2 wt % and TiTIP is in a concentration of about 0.1-2 wt %.

23. The method according to claim 18, further including a step of recycling the catalyst for a next reaction without sacrifice their activity.

24. The method according to claim 20, wherein the ratio of the esterification agent and hydroxyl groups in the polyether polyol is about 1.0-5.0:1.

25. The method according to claim 24, wherein the ratio is about 1.2-2.5:1.

26. The method according to claim 20, further comprising adding a solvent wherein the solvent is any one or a combination of a hydrocarbon solvent and an ether solvent.

27. The method according to claim 26, wherein the hydrocarbon solvent is any one of hexanes, cyclohexane, heptane, octane and toluene, and the ether solvent is any one of dioxane, dimethyl ethylene glycol ether, diethyl ethylene glycol ether, and dimethyl propylene glycol ether.

28. The method according to claim 20, further comprising a step of removing by-product methanol or ethanol.

29. The method according to claim 28, wherein the removing step is carried out by molecular sieves or azeotropic distillation.

30. The method according to claim 20, further comprising a step of adding an inhibitor for polymerization of the esterification agents.

31. The method according to claim 30, wherein the inhibitor is any one or a combination of phenothiazine, methyl hydroquinone (MEDQ), diethylhydroxylamine and nitrosobenzene.

32. The method according to claim 18, wherein the esterification agent used in the reacting step is acrylic acid or methacrylic acid.

33. The method according to claim 32, wherein the catalyst is organosulfonic acid.

34. The method according to claim 33, wherein the organosulfonic acid is any one of toluenesulfonic acid, methanesulfonic acid, and sulfonic based ionic exchange resins.

35. The method according to claim 34, wherein the toluenesulfonic acid or the mathanesulfonic acid is added in a concentration of about 0.1-3 wt %.

36. The method according to claim 34, wherein the sulfonic based ionic exchange resins is added in a concentration of about 2-30 wt %.

37. The method according to claim 32 further comprising a step of adding a polymerization inhibitor and/or a water-azeotropic solvent.

38. The method according to claim 37, wherein the polymerization inhibitor is a phenolic antioxidant or phenothiazine.

39. The method according to claim 38, wherein the phenolic antioxidant is methyl hydroquinone (MEHQ) or butylate hydroxytoluene (BHT).

40. The method according to claim 38, wherein the phenolic antioxidant is added in a concentration of about 100-10,000 ppm and the phenothiazine is added in a concentration of about 100-5,000 ppm.

41. The method according to claim 37, wherein the polymerization inhibitor is added to a Dean Stark to prevent advent polymerization on a fractional column.

42. The method according to claim 37, wherein the solvent is any one or a combination of a hydrocarbon and chlorinate hydrocarbon.

43. The method according to claim 42, wherein the hydrocarbon is hexanes, cyclohexane or heptane, and the chlorinate hydrocarbon is 1,2-dichloroethane, 1,1-dichlorethane or chloroform.

44. The polyether polyol according to claim 10, wherein the substituted cyanuric acid is 1,3,5-Tris(2-hydroxyethyl)cyanuric acid.

45. The method according to claim 16, wherein the multifunctional polyether polyol is a trifunctional polyether polyol.

46. The polyether polyol according to claim 1, wherein the multifunctional alcohol is glycerol or sucrose.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Embodiments disclosed herein will be more fully understood from the following detailed description thereof taken in connection with the accompanying drawings, which form a part of this application, and in which:

[0049] FIG. 1A is an Fourier Transform Infrared (FTIR) spectrum of cyanuric polyether polyol;

[0050] FIG. 1B is an Fourier Transform Infrared (FTIR) spectrum of cyanuric polyether acrylate.

[0051] FIG. 2A is an NMR spectra of polyether; and

[0052] FIG. 2B is an NMR spectra of polyether acrylate.

DETAILED DESCRIPTION

[0053] Various embodiments and aspects of the disclosure will be described herein with reference to details discussed below. The following description and drawings are illustrative of the disclosure and are not to be construed as limiting the disclosure. The drawings are not to scale. Numerous specific details are described to provide a thorough understanding of various embodiments of the present disclosure. However, in certain instances, well-known or conventional details are not described in order to provide a concise discussion of embodiments of the present disclosure.

[0054] As used herein, the terms comprises and comprising are to be construed as being inclusive and open ended, and not exclusive. Specifically, when used in the specification and claims, the terms comprises and comprising and variations thereof mean the specified features, steps or components are included. These terms are not to be interpreted to exclude the presence of other features, steps or components.

[0055] As used herein, the terms about and approximately are meant to cover variations that may exist in the upper and lower limits of the ranges of values, such as variations in properties, parameters, and dimensions.

[0056] Disclosed herein is a method for the synthesis of cyanurate-multifunctional alcohol based, especially cyanurate-glycerol polyether (meth)acrylate and isocyanurate-glycerol-triethanolamine polyether (meth)acrylates for UV curable materials. The inventors have synthesized a special type of polyether (meth)acrylates which is not available in the present market, that is, isocyanurate-glycerol based polyether (meth)acrylates. Compared with present polyethers in the market which are mostly aliphatic polyol based, isocyanurate-glycerol based polyethers have rigid isocyanurate structure, endowing the material extra strength and thermal stability. The triethanolamine unit in isocyanurate-glycerol-triethanolamine polyether (meth)acrylates endows the material with anti-oxygen inhibition property in UV curing process. The isocyanurate-glycerol based polyether (meth)acrylates have low viscosity and high reactivity towards UV cure. The cured resins have high resilience and strength. Thus, isocyanurate-glycerol based polyether (meth)acrylates will have wide applications in UV curable adhesives, coatings, inks, sealants, paints, 3D printing. The applications are literally unlimited.

[0057] The present disclosure mainly includes three key discoveries: 1) the unique method for the synthesis of trifunctional cyanurate-glycerol-poly(propylene oxide) polyether polyols (CGPE, Examples 4, 5, 6 below), 2) synthesis of polyether (meth)acrylates including cyanurate-glycerol-poly(propylene oxide) polyether (meth)acrylates through transesterification (Examples 7, 8, 9 below), synthesis of polyether (meth)acrylates including cyanurate-glycerol-poly(propylene oxide) polyether acrylates through direct esterification (Examples 10, 11, 12 below).

[0058] The process may be described by Scheme 1 shown below.

##STR00002##

Scheme 1 shows the synthesis of cyanuric-glycerol polyether and three functional acrylate UV curable resin.

[0059] The following non-limiting examples give some detailed description of the disclosure, but the scope of the disclosure cannot be limited in the examples.

Example 1

Preparation of 2% KOH-Glycerol (Based on OH Group on Glycerol) Initiation Mixture

[0060] 8.60 g 85% potassium hydroxide was dissolved in 15.00 g distilled water, and then mixed with 200.0 g glycerol in a flask. The mixture is evaporated to remove water through rotary evaporator. The obtained mixture was used for the synthesis of poly (propylene oxide) with different KOH contents.

Example 2

[0061] The Production of Glycerol Poly(Propylene Oxide) Ether Polyol-500 (GPE500) 500 g/mol).

[0062] 6.500 g of the above prepared glycerol-KOH solution and 6.500 g glycerol are added into a parr pressure reactor. The reactor was evacuated and purged with nitrogen several times. Then the reactor heated to around 100 C. 57.75 g propylene oxide is added into the reactor using a pump with the flow rate of 2 ml/min. After that, the reaction temperature is kept at 125 C. for 15 min before cooling down to room temperature. Unreacted propylene oxide was removed by high vacuum evacuation at 35 C. for 2 hours, under 0.10 g loss was found, showing complete conversion of propylene oxide.

Example 3

Production of 25% (Mol) Sucrose-Glycerol Poly(Propylene Oxide) Ether Polyol-600 (SGPE600)

[0063] 11.12 g sucrose, 8.70 g glycerol-KOH solution and 0.500 g glycerol are added into a batch reactor. Nitrogen is used to remove the air in the reactor for three times. Then 20.00 g propylene oxide is added into reactor though a pump and the reaction temperature is increased to around 90 C. for 30 mins. After that, the reaction temperature is increased to around 120 to 130 C. with the addition of 42.60 g propylene oxide at a flow rate of 2 ml/min. The reaction temperature is kept at 130 C. for 30 mins before cooling down to room temperature. Complete conversion of propylene oxide was achieved.

Example 4

Production of 3/7 (Mol) Cyanuric-Glycerol Poly(Propylene Oxide) Ether Polyol-500 (CGPE-500).

[0064] 6.58 g cyanuric acid, 4.10 g of the above prepared glycerol-KOH solution and 7.20 glycerol are added into a batch reactor. Nitrogen was used to remove the air in the reactor for three times and then the reaction temperature was increased to around 120 to 130 C. Next, the 67.27 g propylene oxide was added into the reactor using a pump with the flow rate of 2 ml/min. The reaction temperature was kept at 130 C. for 60 mins before cooling down to room temperature. Complete conversion of propylene oxide was achieved.

Example 5

Production of 3/7 (Mol) Cyanuric-Glycerol Poly(Propylene Oxide) Ether Polyol-500 (CGPE-500) Using 1,3,5-Tris(2-Hydroxyethyl)Cyanuric Acid and Glycerol as Starter.

[0065] 11.75 g 1,3,5-Tris(2-hydroxyethyl)cyanuric acid, 3.60 g of the above prepared glycerol-KOH solution and 6.20 glycerol are added into a batch reactor. Nitrogen was used to remove the air in the reactor for three times and then the reaction temperature was increased to around 120 to 130 C. Next, the 53.50 g propylene oxide was added into the reactor using a pump with the flow rate of 2 ml/min. The reaction temperature was kept at 130 C. for 60 mins before cooling down to room temperature. Complete conversion of propylene oxide was achieved.

Example 6

[0066] Production of (1/3/6 Mol) Triethanolamine-Cyanuric Acid-Glycerol Poly(Propylene Oxide) Ether Polyol TEACGPE 800 g/Mol

[0067] 1.60 g triethanolamine, 4.14 g cyanuric acid, 2.60 g glycerol-KOH solution and 3.50 glycerol were added into a batch reactor. Nitrogen was used to remove the air in the reactor for three times and then the reaction temperature was increased to around 120 to 130 C. Then, 73.83 g propylene oxide was added into the reactor using a pump with at the flow rate of 2 ml/min. After that, the reaction temperature was kept at 130 C. for 60 mins before cooling down to room temperature. Complete conversion of propylene oxide was achieved.

Example 7

[0068] Synthesis of Trifunctional CGPE Acrylate Through Transesterification with Ethyl Acrylate (EA)

[0069] In a 300 mL three-neck flask, one neck was equipped with a pressure balanced addition funnel with a condenser and bubbler on the top. The funnel was filled with 4A molecular sieves. The other two necks were connected with a nitrogen inlet and a thermometer. 60.00 g of the above polyether polyol (molecular weight 500 g/mol) was added, followed by 10.00 g dioxane, 0.35 g titanium tetrachloride, the mixture was stirred for 15 min under nitrogen flow. Then 0.2 g phenothiazine (PTZ) was added, followed by 72.00 g of EA. The mixture was purged with nitrogen for 15 min, then was refluxed at in a 115 C. oil bath with magnetic stirring for 8 hours. After cooling to room temperature, the reaction mixture was diluted with dichloromethane, centrifuged. The solvent and unreacted EA in liquid mixture was removed in a rotary evaporator under vacuum, left the product polyether acrylate in the distillation flask. EA and dioxane as a mixture which can be reused as feedstock for the next reaction was recovered by removing dichlormethane by fractional distillation. The FTIR spectra shown in FIGS. 1A and 1B and the NMR spectra shown in FIGS. 2A and 2B show almost complete conversion of the hydroxyl groups to acrylate groups. More particularly, in the FTIR spectrum shown in FIG. 1A, the broad peak at 3400 cm.sup.1 is the hydroxyl group in cyanuric polyether polyol. In the FTIR spectrum of the acrylation product shown in FIG. 1B, the hydroxyl group is completely converted to acrylate group which shows a strong peak at 1720 cm.sup.1 which is the carbonyl group of acrylate overlapped with the carbonyl group of isocyanuric ring. In the proton NMR shown in FIG. 2A, the peak at 3.8 ppm disappeared after acrylation, and the new three strong peaks between 5.5 and 6.5 ppm in FIG. 2B prove the presence of three protons attached to CC double bond of the acrylate.

Example 8

[0070] Synthesis of Trifunctional CGPE Acrylate Through Transesterification with Methyl Acrylate (MA)

[0071] In a 300 mL three-neck flask, one neck was equipped with a pressure balanced addition funnel with a condenser and bubbler on the top. The funnel was filled with 4A molecular sieves. The other two necks were connected with a nitrogen inlet and a thermometer. 60.00 g of the above polyether polyol (molecular weight 500 g/mol) was added, followed by 15.00 g ethylene diethyl ether, 0.25 g titanium tetrachloride, the mixture was stirred for 15 min under nitrogen flow. Then 0.5 g diethylhydroxylamine, 0.1 g phenothiazine (PTZ) was added, followed by 62.00 g of MA. The mixture was purged with nitrogen for 15 min, then was refluxed in a 110 C. oil bath with magnetic stirring for 8 hours. After cooling to room temperature, the reaction mixture was diluted with dichloromethane, centrifuged. The solvent and unreacted MA in liquid mixture was removed in a rotary evaporator under vacuum, left the product polyether acrylate in the distillation flask. MA and ethylene diethyl ether as a mixture which can be reused as feedstock for the next reaction was recovered by removing dichlormethane by fractional distillation. FTIR spectrum shows almost complete conversion of the hydroxyl groups to acrylate groups.

Example 9

[0072] Synthesis of Trifunctional CGPE Acrylate Through Transesterification with Methyl Acrylate (MA)

[0073] In a 250 mL three-neck flask, one neck was equipped with a fractional column with Dean Stark, a condenser and bubbler sequentially on the top. The dean Stark was filled with a solution of 0.5% diethylhydroxylamine in hexanes. The fractional column is filled with glass spring. The other two necks were connected with a nitrogen inlet and a thermometer. 60.00 g of the above polyether polyol (molecular weight 500 g/mol) was added, followed by 5.00 g hexanes, 15.00 g ethylene diethyl ether, 0.25 g titanium tetrachloride, the mixture was stirred for 15 min under nitrogen flow. Then 0.1 g phenothiazine (PTZ) was added, followed by 62.00 g of MA. The mixture was purged with nitrogen for 15 min, then was refluxed in a 110 C. oil bath with magnetic stirring for 8 hours. After cooling to room temperature, the reaction mixture was diluted with dichloromethane, centrifuged. The solvent and unreacted MA in liquid mixture was removed in a rotary evaporator under vacuum, left the product polyether acrylate in the distillation flask. MA and ethylene diethyl ether as a mixture which can be reused as feedstock for the next reaction was recovered by removing dichlormethane by fractional distillation. FTIR spectrum shows almost complete conversion of the hydroxyl groups to acrylate groups.

Example 10

[0074] Synthesis of Trifunctional CGPE Acrylate Through Direct Esterification with Acrylic Acid (AA)

[0075] In a 300 mL three-neck flask, one neck was equipped with a fractional column with a Dean Stark, a condenser, and bubbler on the top. The Dean Stark was filled with butylated hydroxyl toluene dissolved in cyclohexane. The other two necks were connected with a gas inlet and a thermometer. 60.00 g of the polyether polyol (molecular weight 500 g/mol) was added, followed by 20.00 g cyclohexane, 1.0 g methyl hydroquinone, 3.0 g toluenesulfonic acid, and 52.0 g acrylic acid. The mixture was refluxed in a 110 C. oil bath with magnetic stirring for 6 hours at 2 ml/min air flow. After cooling to room temperature, the reaction mixture was diluted with dichloromethane, neutralized with potassium carbonate, and centrifuged. The solvent and unreacted AA in liquid mixture was removed in a rotary evaporator under vacuum, left the product polyether acrylate in the distillation flask. AA and cyclohexane as a mixture which can be reused as feedstock for the next reaction was recovered by removing dichlormethane by fractional distillation. FTIR spectrum shows almost complete conversion of the hydroxyl groups to acrylate groups.

Example 11

[0076] Synthesis of Trifunctional CGPE Acrylate Through Direct Esterification with Acrylic Acid (AA)

[0077] In a 300 mL three-neck flask, one neck was equipped with a fractional column with a Dean Stark, a condenser, and bubbler on the top. The Dean Stark was filled with phenothiazine dissolved in cyclohexane. The other two necks were connected with a gas inlet and a thermometer. 60.00 g of the polyether polyol (molecular weight 500 g/mol) was added, followed by 20.00 g cyclohexane, 0.1 g phenothiazine, 3.0 g toluenesulfonic acid, and 52.0 g acrylic acid. The mixture was refluxed in a 110 C. oil bath with magnetic stirring for 6 hours at 2 ml/min nitrogen flow. After cooling to room temperature, the reaction mixture was diluted with dichloromethane, neutralized with potassium carbonate, and centrifuged. The solvent and unreacted AA in liquid mixture was removed in a rotary evaporator under vacuum, left the product polyether acrylate in the distillation flask. AA and cyclohexane as a mixture which can be reused as feedstock for the next reaction was recovered by removing dichlormethane by fractional distillation. FTIR spectrum shows almost complete conversion of the hydroxyl groups to acrylate groups.

Example 12

[0078] Synthesis of Trifunctional CGPE Acrylate Through Direct Esterification with Acrylic Acid (AA)

[0079] In a 300 mL three-neck flask, one neck was equipped with a fractional column with a Dean Stark, a condenser, and bubbler on the top. The Dean Stark was filled with phenothiazine dissolved in cyclohexane. The other two necks were connected with a gas inlet and a thermometer. 60.00 g of the polyether polyol (molecular weight 500 g/mol) was added, followed by 20.00 g cyclohexane, 0.1 g phenothiazine, 10.00 g Amberlyst 15, and 52.0 g acrylic acid. The mixture was refluxed in a 110 C. oil bath with magnetic stirring for 6 hours at 2 ml/min nitrogen flow. After cooling to room temperature, the reaction mixture was diluted with dichloromethane, filtered. The Amberlyst can be reused. The solvent and unreacted AA in liquid mixture was removed in a rotary evaporator under vacuum, left the product polyether acrylate in the distillation flask. AA and cyclohexane as a mixture which can be reused as feedstock for the next reaction was recovered by removing dichlormethane by fractional distillation. FTIR spectrum shows almost complete conversion of the hydroxyl groups to acrylate groups. The synthesized poly(propylene oxide) polyether acrylates have a viscosity range of 100 cP to 200 cP, so they can be used directly as UV curing materials. Examples 6-11 for the synthesis of polyether acrylates can apply for all the polyether polyols synthesized in examples 1-5.

Example 13

UV Curing of Poly(Propylene Oxide) Polyether Acrylates

[0080] Various of poly(propylene oxide) polyether acrylates were mixed with 3% UV initiator 2-Hydroxy-2-methylpropiophenone (Daracure 1173, or 1173) and cured under 600 watt UN light. The results show that polyether acrylate products with isocyanurate unit having higher strength, and triethanolamine provides anti-oxygen inhibition effect. (no data).

[0081] The foregoing description of the preferred embodiments of the disclosure has been presented to illustrate the principles of the disclosure and not to limit the disclosure to the particular embodiment illustrated. It is intended that the scope of the disclosure be defined by all of the embodiments encompassed within the following claims and their equivalents.