Degradable sulfur-containing hyperbranched epoxy resin and preparation method thereof

Abstract

Degradable sulfur-containing hyperbranched epoxy resin and a preparation method thereof. The preparation method comprises initiating a reaction of a mercaptocyclotriazine compound and a binary olefin by ultraviolet light to prepare a mercapto hyperbranched polymer; then reacting with glycidyl methacrylate to obtain a degradable sulfur-containing hyperbranched epoxy resin of which the molecular weight is about 3,000-35,400 g/mol. After the degradable sulfur-containing hyperbranched epoxy resin is cured, a cyclotriazine structure can be completely degraded within 1.5 h in a phosphoric acid solution at the temperature of 80 DEG C, thus realizing the recycle of the epoxy resin. The invention is simple in process, low in reaction temperature, rapid in reaction and high in yield, the sulfur-containing structure lowers curing temperature and realizes rapid curing, and cyclotriazine structure has a degradation function, and is expected to be used in the fields of strengthening and toughening of the epoxy resins, solvent-free coatings, electronic packaging.

Claims

1. A degradable sulfur-containing hyperbranched epoxy resin, having structural formula: ##STR00008## wherein R.sub.7 is ##STR00009## R.sub.8 is ##STR00010## R.sub.1 is C.sub.6H.sub.4(CH.sub.2).sub.r or CH.sub.2(CH.sub.2).sub.k, r=1, 2, 3 or 4, k=2, 3, 4 or 5, and a benzene ring in the C.sub.6H.sub.4(CH.sub.2).sub.r is para-, meta- or ortho-substituent and is an amino substituted benzene ring structure; R.sub.3 is H or CH.sub.3, and when R.sub.3 is H, R.sub.2=CH.sub.2O(CH.sub.2).sub.mOCH.sub.2 or COO(CH.sub.2).sub.mOOC, where m=2, 3, 4, 5 or 6; when R.sub.3 is CH.sub.3, R.sub.2=COO(CH.sub.2).sub.mOOC, where m=2, 3, 4, 5 or 6; R.sub.4 is H or CH.sub.3, and when R.sub.4 is H, R.sub.5=OCH.sub.2; when R.sub.4 is CH.sub.3, and R.sub.5=OCO; ##STR00011##

2. A preparation method of the degradable sulfur-containing hyperbranched epoxy resin according to claim 1, comprising steps of (a) uniformly mixing a trimercaptocyclotriazine compound B3, a diolefin compound A2, a photoinitiator and an organic solvent, reacting under 800-3,000 W ultraviolet light for 10-30 minutes at room temperature, vacuum-extracting the organic solvent to obtain a mercapto-terminated hyperbranched polymer, wherein the trimercaptocyclotriazine compound B3 is ##STR00012## R1 is C.sub.6H.sub.4(CH.sub.2).sub.r or CH.sub.2(CH.sub.2).sub.k, r=1, 2, 3 or 4, k=2, 3, 4 or 5, and a benzene ring in the C.sub.6H.sub.4(CH.sub.2)r- is para-, meta- or ortho-substituent and is an amino substituted benzene ring structure; the diolefin compound A2 is CH.sub.2C(R.sub.3)R.sub.2(R.sub.3)CCH.sub.2, R.sub.3 is H or CH.sub.3, and when R.sub.3 is H, R.sub.2=CH.sub.2O(CH.sub.2).sub.mOCH.sub.2 or COO(CH.sub.2).sub.mOOC, where m=2, 3, 4, 5 or 6; when R3 is CH.sub.3, R.sub.2=COO(CH.sub.2).sub.mOOC, where m=2, 3, 4, 5 or 6; and (b) uniformly mixing the mercapto-terminated hyperbranched polymer, an epoxy compound, a photoinitiator and an organic solvent, then carrying out a thiol-olefin click reaction under 800-3,000 W ultraviolet light for 10-30 minutes at room temperature, vacuum-extracting the organic solvent and the excess epoxy compound to obtain the degradable sulfur-containing hyperbranched epoxy resin.

3. The preparation method according to claim 2, wherein the epoxy compound in the step (b) is glycidyl methacrylate or allyl glycidyl ether.

4. The preparation method according to claim 3, wherein molar ratio of the trimercaptocyclotriazine compound B3 to the diolefin compound A2 in the step (a) is (1-1.5):1.

5. The preparation method according to claim 3, wherein molar ratio of the mercapto group in the mercapto-terminated hyperbranched polymer to the epoxy compound in the step (b) is 1:(1-2.5).

6. The preparation method according to claim 3, wherein the photoinitiator in the step (a) is one or more than two of benzophenone, p-aminopropiophenone, and 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone, and the photoinitiator is used in an amount of 0.5-3% by mass of the trimercaptocyclotriazine compound.

7. The preparation method according to claim 3, wherein the photoinitiator in the step (b) is one or more than two of benzophenone, p-aminopropiophenone, and 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone, and the photoinitiator is used in an amount of 0.5-3% by mass of the mercapto-terminated hyperbranched polymer.

8. The preparation method according to claim 3, wherein the organic solvent in the step (a) is one or more than two of methanol, ethanol, tetrahydrofuran, dioxane, ethyl acetate and butyl acetate, and the organic solvent is used in an amount of 0.5-3.0 times the mass of the trimercaptocyclotriazine compound.

9. The preparation method according to claim 3, wherein the organic solvent in the step (b) is one or two of methanol, ethanol, tetrahydrofuran, dioxane, ethyl acetate and butyl acetate, and the organic solvent is used in an amount of 0.5-3.0 times the mass of the mercapto-terminated hyperbranched polymer.

10. The preparation method according to claim 2, wherein the degradable sulfur-containing hyperbranched epoxy resin has a molecular weight of 3,000-35,400 g/mol.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) The invention is described in detail below with reference to specific embodiments, but these embodiments should not be construed as limiting the scope of the invention in any way.

(2) The molecular weights of the products are determined by using GPC from British PL Company. The epoxy value is determined by the national standard hydrochloric acid acetone method, and the viscosity is measured by using a Brookfield viscometer at 25 C.

(3) The cyclotriazine compounds B3 (i.e.,

(4) ##STR00007##
in the following embodiments are self-made by the inventors of the present application, and the specific preparation process is as follows:

(5) Preparation of Compound B3:

(6) The preparation of the mercapto cyclotriazine compound B3 is carried out based on the reaction principle of the reference (Science 2014, 344, (6185), 732-735), and its specific process steps are as follows: 0.1 mol of p-aminophenylmethyl mercaptan H.sub.2NC.sub.6H.sub.4CH.sub.2SH (R1=C.sub.6H.sub.4CH.sub.2), 0.20 mol of trioxymethylene, and 60 mL of distilled water are placed in a three-necked flask equipped with a condenser, a thermometer and a stirrer, and then stirred to react for 8 hours at a temperature of about 30 C., and the reaction is terminated. The water and unreacted formaldehyde are removed by rotary evaporation under the conditions of a vacuum degree of 2-3 mmHg and a temperature of about 60 C. to obtain a tris(4-mercaptomethyl-phenyl)cyclotriazine compound denoted as B3-01, with a yield of about 85%. The remaining B3 compounds can be obtained in a similar manner with yields between 70% and 90%. The corresponding compounds are denoted as B3-02 (R.sub.1=C.sub.6H.sub.4(CH.sub.2).sub.2), B3-03 (R.sub.1=C.sub.6H.sub.4(CH.sub.2).sub.4), B3-04 (R.sub.1=CH.sub.2(CH.sub.2).sub.2), B3-05 (R.sub.1=CH.sub.2(CH.sub.2).sub.3), and B3-06 (R.sub.1=CH.sub.2(CH.sub.2).sub.5).

Embodiment 1

(7) A degradable sulfur-containing hyperbranched epoxy resin prepared by the following method:

(8) (a) 0.4 mol (181.2 g) of a trimercapto cyclotriazine B3-01, 0.3 mol (42.6 g) of a diolefin compound CH.sub.2CHCH.sub.2O(CH.sub.2).sub.2OCH.sub.2CHCH.sub.2, 112.0 g of methanol and 1.12 g of a photoinitiator benzophenone are mixed uniformly and react under 800 W ultraviolet light for 30 minutes at room temperature, and the organic solvent methanol is then vacuum-extracted to obtain a mercapto-terminated hyperbranched polymer (THHBP-a6, containing 6 mol of mercapto group per mol of THHBP-a6), having a number average molecular weight of about 2,200 g/mol.

(9) (b) 0.1 mol (220 g) of the mercapto-terminated hyperbranched polymer THHBP-a6, 0.63 mol of GMA, 110.0 g of tetrahydrofuran and 2.0 g of the photoinitiator benzophenone are uniformly mixed at room temperature and subjected to a thiol-olefin click reaction under 1,500 W ultraviolet light for 20 minutes at room temperature, and the organic solvent and excess GMA are then vacuum-extracted to obtain a degradable sulfur-containing hyperbranched epoxy resin having a number average molecular weight of about 3,000 g/mol, a 25 C. viscosity of 1,300 cp, an epoxy value of 0.20 mol/100 g, and a yield of 99.2%.

Embodiment 2

(10) A degradable sulfur-containing hyperbranched epoxy resin prepared by the following method:

(11) (a) 0.23 mol (113.9 g) of a cyclotriazine B3-02, 0.225 mol (38.25 g) of a diolefin compound CH.sub.2CHCH.sub.2O(CH.sub.2).sub.4OCH.sub.2CHCH.sub.2, 152.0 g of ethanol and 4.5 g of a photoinitiator 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone are mixed uniformly and react under 3000 W ultraviolet light for 10 minutes at room temperature, and the organic solvent ethanol is then vacuum-extracted to obtain a mercapto-terminated hyperbranched polymer (THHBP-48, containing 48 mol of mercapto group per mol of THHBP-48), having a number average molecular weight of about 30,000 g/mol.

(12) (b) 0.01 mol (300 g) of the mercapto-terminated hyperbranched polymer THHBP-48, 1.05 mol (119.7 g) of AGE, 300 g of ethyl acetate and 3.0 g of a photoinitiator p-aminopropiophenone are uniformly mixed at room temperature and subjected to a thiol-olefin click reaction under 3,000 W ultraviolet light for 10 minutes at room temperature, and the organic solvent and excess AGE are then vacuum-extracted to obtain a degradable sulfur-containing hyperbranched epoxy resin having a number average molecular weight of about 35,400 g/mol, a 25 C. viscosity of 3,200 cp, an epoxy value of 0.13 mol/100 g, and a yield of 99.5%.

Embodiment 3

(13) A degradable sulfur-containing hyperbranched epoxy resin prepared by the following method:

(14) (a) 0.05 mol (28.95 g) of a cyclotriazine B3-03, 0.045 mol (7.65 g) of a diolefin compound CH.sub.2CHCOO(CH.sub.2).sub.2OOCCHCH.sub.2, 109.8 g of butyl acetate and 1.1 g of a photoinitiator p-aminopropiophenone are mixed uniformly and react under 2,000 W ultraviolet light for 15 minutes at room temperature, and the organic solvent butyl acetate is then vacuum-extracted to obtain a mercapto-terminated hyperbranched polymer (THHBP-a12, containing 12 mol of mercapto group per mol of THHBP-a12), having a number average molecular weight of about 7,300 g/mol.

(15) (b) 0.01 mol (73 g) of the mercapto-terminated hyperbranched polymer THHBP-a12, 0.24 mol (27.4 g) of AGE, 219 g of ethyl acetate and 2.19 g of the photoinitiator p-aminopropiophenone are uniformly mixed at room temperature and subjected to a thiol-olefin click reaction under 2,000 W ultraviolet light for 15 minutes at room temperature, and the organic solvent and excess AGE are then vacuum-extracted to obtain a degradable sulfur-containing hyperbranched epoxy resin having a number average molecular weight of about 8,600 g/mol, a 25 C. viscosity of 1,900 cp, an epoxy value of 0.14 mol/100 g, and a yield of 99.3%.

Embodiment 4

(16) A degradable sulfur-containing hyperbranched epoxy resin prepared by the following method:

(17) (a) 0.11 mol (34.0 g) of a cyclotriazine B3-04, 0.105 mol (23.73 g) of a diolefin compound CH.sub.2CHCOO(CH.sub.2).sub.6OOCCHCH.sub.2, 34.0 g of methanol and 0.68 g of a photoinitiator 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone are mixed uniformly and react under 1,000 W ultraviolet light for 20 minutes at room temperature, and the organic solvent methanol is then vacuum-extracted to obtain a mercapto-terminated hyperbranched polymer (THHBP-24, containing 24 mol of mercapto group per mol of THHBP-24), having a number average molecular weight of about 11,500 g/mol.

(18) (b) 0.01 mol (115 g) of the mercapto-terminated hyperbranched polymer THHBP-24, 0.36 mol (41.04 g) of AGE, 200 g of dioxane and 2.0 g of a photoinitiator p-aminopropiophenone are uniformly mixed at room temperature and subjected to a thiol-olefin click reaction under 2,000 W ultraviolet light for 12 minutes at room temperature, and the organic solvent and excess AGE are then vacuum-extracted to obtain a degradable sulfur-containing hyperbranched epoxy resin having a number average molecular weight of about 14,200 g/mol, a 25 C. viscosity of 2,100 cp, an epoxy value of 0.16 mol/100 g, and a yield of 99.6%.

Embodiment 5

(19) A degradable sulfur-containing hyperbranched epoxy resin prepared by the following method:

(20) (a) 0.10 mol (35.1 g) of a cyclotriazine B3-05, 0.09 mol (17.82 g) of a diolefin compound CH.sub.2C(CH.sub.3)COO(CH.sub.2).sub.2OOC(CH.sub.3)CCH.sub.2, 17.5 g of dioxane and 0.3 g of a photoinitiator benzophenone are mixed uniformly and react under 2,000 W ultraviolet light for 10 minutes at room temperature, and the organic solvent is then vacuum-extracted to obtain a mercapto-terminated hyperbranched polymer (THHBP-b12, containing 12 mol of mercapto group per mol of THHBP-b12), having a number average molecular weight of about 5,200 g/mol.

(21) (b) 0.01 mol (52 g) of the mercapto-terminated hyperbranched polymer THHBP-b12, 0.24 mol (34.08 g) of GMA, 100 g of dioxane and 1.0 g of a photoinitiator p-aminopropiophenone are uniformly mixed at room temperature and subjected to a thiol-olefin click reaction under 1,500 W ultraviolet light for 20 minutes at room temperature, and the organic solvent and excess GMA are then vacuum-extracted to obtain a degradable sulfur-containing hyperbranched epoxy resin having a number average molecular weight of about 6,900 g/mol, a 25 C. viscosity of 1,700 cp, an epoxy value of 0.17 mol/100 g, and a yield of 99.5%.

Embodiment 6

(22) A degradable sulfur-containing hyperbranched epoxy resin prepared by the following method:

(23) (a) 0.2 mol (87.0 g) of a cyclotriazine B3-06, 0.15 mol (33.9 g) of a diolefin compound CH.sub.2C(CH.sub.3)COO(CH.sub.2).sub.4OOC(CH.sub.3)CCH.sub.2, 100.0 g of methanol and 0.44 g of a photoinitiator 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone are mixed uniformly and react under 1,000 W ultraviolet light for 20 minutes at room temperature, and the organic solvent methanol is then vacuum-extracted to obtain a mercapto-terminated hyperbranched polymer (THHBP-b6, containing 6 mol of mercapto group per mol of THHBP-b6), having a number average molecular weight of about 2,400 g/mol.

(24) (b) 0.01 mol (24 g) of the mercapto-terminated hyperbranched polymer THHBP-b6, 0.132 mol (15.05 g) of AGE, 60 g of dioxane and 0.6 g of a photoinitiator p-aminopropiophenone are uniformly mixed at room temperature and subjected to a thiol-olefin click reaction under 2,000 W ultraviolet light for 15 minutes at room temperature, and the organic solvent and excess AGE are then vacuum-extracted to obtain a degradable sulfur-containing hyperbranched epoxy resin having a number average molecular weight of about 3,000 g/mol, a 25 C. viscosity of 1,100 cp, an epoxy value of 0.20 mol/100 g, and a yield of 99.8%.

(25) A curing agent 4,4-diaminodiphenylmethane is respectively uniformly mixed with each of the degradable sulfur-containing hyperbranched epoxy resins obtained in Embodiments 1-6 and a bisphenol A epoxy resin (E51, having a epoxy value of 0.51 mol/100 g) in the same way under the condition of an equimolar ratio of the hydrogen equivalent of the curing agent to the epoxy value of the hyperbranched epoxy resin, and then the mixture is cured into a film, and specifically, the mixture is first cured for 6 hours at 80-90 C., and then heated to 150-160 C. and cured for 4 hours. The pencil hardness and wear resistance of the film are tested according to the national standards GB/T6739-1996 and GB/T1768-2006, and the properties are shown in Table 1. 0.5 g of the above cured film is ground into a powder, and then degraded by 12 mL of a 0.5 mol/L aqueous phosphoric acid solution. After being stirred at 80 C. for 1.5 hours, the solution is filtered, and the filter cake is dried for 2 hours at 120 C. The degradation rate of the cured powder is then analyzed and the data is shown in Table 1.
Degradation rate (%)=(1mass of the dried filter cake/mass of cured powder)*100%;

(26) TABLE-US-00001 TABLE 1 Properties of Degradable Hyperbranched Epoxy Resin Products Prepared in Embodiments 1-6 Pencil Wear resistance Resin type hardness (mg/1000 rpm) Degradation rate (%) Epoxy resin E51 4H 17.36 9.2 Embodiment 1 4H 13.20 99.6 Embodiment 2 4H 10.52 99.7 Embodiment 3 4H 12.36 99.5 Embodiment 4 4H 10.87 99.7 Embodiment 5 4H 11.34 99.6 Embodiment 6 3H 14.05 99.6