DCPD-derived polyether and method of producing the same

Abstract

A low-k, non-flammable dicyclopentdiene (DCPD)-derived polyether and a method of producing the same are introduced. Incorporation of a phosphorus group and a DCPD derivative into a low-k, non-flammable dicyclopentdiene (DCPD)-derived polyether enable the DCPD-derived polyether to not only serve as an epoxy resin curing agent but also cure itself such that the cured product not only features satisfactory thermal properties and low-k characteristics but is also non-flammable.

Claims

1. A dicyclopentdiene (DCPD)-derived polyether expressed by structural formula (I) below, ##STR00020## where R is, ##STR00021## where n=10-100; wherein the dicyclopentdiene (DCPD)-derived polyether is made by the steps of: (1) allowing a compound expressed by structural formula (A) below ##STR00022## to react with 4,4-difluorobenzophenone by alkaline catalysis to obtain polymer (B) ##STR00023## (2) allowing polymer (B) to react with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and phenol by acid catalysis to obtain DCPD-derived polyether expressed by structural formula (I-a) below, ##STR00024## where n=10-100; and (3) allowing the polyether expressed by structural formula (I-a) to react with methacrylic anhydride by alkaline catalysis to obtain the dicyclopentdiene (DCPD)-derived polyether, wherein the DCPD-derived polyether has a glass transition temperature around 290 C.

2. A cured product produced by heating and curing constituents of the polyether of claim 1.

3. The method of claim 1, wherein an alkali in step (1) is K.sub.2CO.sub.3.

4. The method of claim 1, wherein the reaction in step (1) further requires p-benzoquinone which functions as a radical inhibitor.

5. The method of claim 1, wherein an acid in step (2) is H.sub.2SO.sub.4.

6. The method of claim 1, further comprising allowing the polyether expressed by structural formula (I-a) to react with methacrylic anhydride by alkaline catalysis to obtain the polyether expressed by structural formula (I-c) below, ##STR00025## where n=10-100.

7. The dicyclopentdiene (DCPD)-derived polyether of claim 1, wherein the dielectric constant of the dicyclopentdiene (DCPD)-derived polyether is 2.72.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a structural formula of a DCPD-derived polyether of the present invention;

(2) FIG. 2 is a schematic view of the process flow of a method of producing the DCPD-derived polyether of the present invention;

(3) FIG. 3A is a 600 MHz .sup.1H-NMR spectrum of the DCPD-2,6-diol in a CDCl.sub.3 solution;

(4) FIG. 3B is a .sup.1H-NMR spectrum of the DCPD-derived polyether according to embodiment 1 of the present invention;

(5) FIG. 4 is a .sup.1H-NMR spectrum of the DCPD-derived polyether according to embodiment 2 of the present invention;

(6) FIG. 5 is a .sup.1H-NMR spectrum of the DCPD-derived polyether according to embodiment 3 of the present invention;

(7) FIG. 6 is a .sup.1H-NMR spectrum of the DCPD-derived polyether according to embodiment 4 of the present invention;

(8) FIG. 7 is a .sup.1H-NMR spectrum of the DCPD-derived polyether according to embodiment 5 of the present invention;

(9) FIG. 8 shows the findings in dynamic mechanical analysis (DMA) of the DCPD-derived polyether according to an embodiment of the present invention;

(10) FIG. 9 shows the findings in thermomechanical analysis (TMA) of the DCPD-derived polyether according to an embodiment of the present invention; and

(11) FIG. 10 shows the findings in thermogravimetric analysis (TGA) of the DCPD-derived polyether according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(12) Implementation of the present invention is hereunder illustrated by a specific embodiment. Persons skilled in the art can easily understand other advantages and effects of the present invention by referring to the disclosure contained in the specification.

(13) Incorporation of a phosphorus group and a DCPD derivative into a low-k, non-flammable dicyclopentdiene (DCPD)-derived polyether of the present invention enables the DCPD-derived polyether of the present invention to not only serve as an epoxy resin curing agent but also cure itself such that the cured product not only features satisfactory thermal properties and low-k characteristics but is also non-flammable.

(14) Referring to FIG. 2, there is shown, there is shown a schematic view of the process flow of a method of producing the DCPD-derived polyether of the present invention. As shown in the diagram, the method of producing the DCPD-derived polyether of the present invention comprises steps of: (1) allowing a compound expressed by structural formula (A) below

(15) ##STR00009##

(16) to react with 4,4-difluorobenzophenone by alkaline catalysis to obtain polymer (B)

(17) ##STR00010##
and

(18) (2) allowing polymer (B) to react with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and phenol by acid catalysis to obtain DCPD-derived polyether expressed by structural formula (I-a) below,

(19) ##STR00011##
where n=10-100.

(20) In an embodiment of the present invention, the method further comprises allowing the polyether expressed by structural formula (I-a) to react with acetic anhydride by alkaline catalysis to obtain the polyether expressed by structural formula (I-b),

(21) ##STR00012##
where n=10-100.

(22) In an embodiment of the present invention, the method further comprises allowing the polyether expressed by structural formula (I-a) to react with methacrylic anhydride by alkaline catalysis to obtain the polyether expressed by structural formula (I-c) below,

(23) ##STR00013##
where n=10-100.

(24) In an embodiment of the present invention, the method further comprises allowing the polyether expressed by structural formula (I-a) to react with 4-vinylbenzyl chloride by alkaline catalysis to obtain the polyether expressed by structural formula (I-d) below,

(25) ##STR00014##
where n=10-100.

Embodiment

(26) Embodiment 1: 87.3 g (0.714 mol) of 2,6-dimethyl phenol and 2.0 g (0.015 mol) of AlCl.sub.3 were added to a 250 mL three-neck reactor, stirred in a nitrogen atmosphere, and heated to 120 C. Then, 12.32 g (0.100 mol) of dicyclopentadiene (DCPD) was pipetted into the 250 mL three-neck reactor to undergo a reaction for 6 hours. Upon completion of the reaction, 0.060 mol of 5 wt % NaOH (aq) was added to the 250 mL three-neck reactor and stirred for one hour. Afterward, the resultant solution underwent suction filtration, and the resultant filtrate was rinsed thrice with deionized water. The organic layer of the rinsed filtrate was concentrated under reduced pressure to remove a surplus portion of 2,6-dimethyl phenol. Afterward, the product thus preliminarily concentrated under reduced pressure was dissolved in toluene and then extracted several times with deionized water such that the organic layer was concentrated under reduced pressure to remove the toluene and water, thereby obtaining dark brown DCPD-2,6-diol solid expressed by structural formula (A). Referring to FIG. 3B, there is shown a .sup.1H-NMR spectrum of the DCPD-derived polyether according to embodiment 1 of the present invention. As shown in the FIG. 3A, there is shown a 600 MHz .sup.1H-NMR spectrum of the DCPD-2,6-diol in a CDCl.sub.3 solution, which shows a characteristic peak of an alkyl group of DCPD and a characteristic peak of a methyl group of dimethyl phenol at 1.0 ppm2.8 ppm, a characteristic peak of a benzene ring at 6.6 ppm7.0 ppm, and a characteristic peak of OH of the benzene ring at 4.43 ppm4.76 ppm. Considering the aforesaid findings, it was confirmed that monomer DCPD-2,6-diol were successfully synthesized. Afterward, DCPD-2,6-diol undergoes nucleophilic substituted polymerization with 4,4-difluorobenzophenone by alkaline catalysis by following steps as follows: 10 g (0.0245 mole) of DCPD-2,6-diol, 5.795 g (0.0245 mole) of 4,4-difluorobenzophenone, 6.28 g of (0.02452 mol) of K.sub.2CO.sub.3, 0.1 g of p-benzoquinone, 10 mL of xylene, and 47.39 g of N-methyl-2-pyrrolidinone (NMP) were added to a 100 mL three-neck reactor, and then the resultant solution was heat therein in a nitrogen atmosphere to 150 C. to react for 24 hours with xylene as an azeotropic agent; upon completion of the reaction, methanol was added to the 100 mL three-neck reactor to precipitate a black solid; the resultant solution was rinsed with methanol and water and then subjected to suction filtration; the resultant filter cake was dried in vacuum at 70 C. to obtain a black solid product, that is, polymer (B). Referring to FIG. 3B, there is shown a .sup.1H-NMR spectrum of the DCPD-derived polyether according to embodiment 1 of the present invention. As shown in the diagram, a 400 MHz .sup.1H-NMR spectrum of polymer (B) in DMSO-d.sub.6 deuterated solution shows the disappearance of a characteristic peak of ArOH of DCPD bisphenol monomer derivative at 7.9 ppm and the appearance of a characteristic peak of ArH of DCPD bisphenol monomer derivative at 6.67.8 ppm. Considering the findings, it was confirmed that polymer (B) was successfully synthesized.

(27) Comparison 1: 10 g (0.0245 mole) of DCPD-2,6-diol, 5.795 g (0.0245 mole) of 4,4-difluorobenzophenone, 6.28 g (0.02452 mol) of K.sub.2CO.sub.3, 10 mL of xylene and 47.39 g of NMP were added to a 100 mL three-neck reactor and heated therein in a nitrogen atmosphere to 180 C. to react for 6 hours with xylene as an azeotropic agent. However, the reaction ended up with gelation and yielded no polymer of structural formula (B).

(28) Comparison 2: comparison 2 is substantially the same as comparison 1 but different from comparison 1 in that comparison 2 requires the reaction to take place at 150 C. for 8 hours. However, the reaction ended up with gelation and yielded no intended product.

(29) Comparison 3: comparison 3 is substantially the same as comparison 1 but different from comparison 1 in that comparison 3 requires the reaction to

(30) ##STR00015##
take place at 120 C. for 10 hours. However, the reaction ended up with gelation and yielded no intended product.

(31) Comparison 4: 10 g (0.0245 mole) of DCPD-2,6-diol, 5.795 g (0.0245 mole) of 4,4-difluorobenzophenone, 7.44 g (0.02452 mol) of CsF, 10 mL of xylene and 47.39 g of NMP were added to a 100 mL three-neck reactor and heated therein in a nitrogen atmosphere to 150 C. to react for 24 hours with xylene as an azeotropic agent. Upon completion of the reaction, the resultant solution was introduced into methanol to precipitate a black solid. Afterward, the black solid was rinsed with methanol and water and then underwent suction filtration. Finally, the resultant filter cake was dried in vacuum at 70 C. to obtain a black solid product. However, the findings in a NMR spectrum show that the reaction did not yield polymer (B).

(32) Gelation occurs in the course of producing polymer (B) and remains unabated despite lowering the reaction temperature and extending the reaction duration (as in comparisons 1, 2, 3). The reaction does not even occur when the catalyst is changed (as in comparison 4), because in the course of the reaction, the methyl group and CO may undergo radical coupling and produce a cross-linking product, leading to gelation. In view of this, the present invention is advantageous in that in the course of producing polymer (B) radical inhibitor p-benzoquinone (as in embodiment 1) was introduced to prevent production of radicals such that the reaction took place for 24 hours without causing gelation. Afterward, gel permeation chromatography (GPC) was performed, showing a marked increase in molecular weight.

(33) Embodiment 2: polymer (I-a) was produced from polymer (B), organic cyclic phosphorus-containing compound, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), and excessive phenol by acid catalysis by following the steps as follows: 10 g (0.01796 mol) of polymer (B), 42.7 g (0.01796 mmol) of DOPO, 33.8 g (0.0179620 mol) of phenol and 0.17 g (4 wt % based on DOPO) of H.sub.2SO.sub.4 were added to a 100 mL three-neck reactor and heated therein in a nitrogen atmosphere to 150 C. to react for 24 hours. Upon completion of the reaction, the resultant solution was introduced into methanol to precipitate a black solid. Afterward, the black solid was rinsed with methanol and water and then underwent suction filtration. Finally, the resultant filter cake was dried in vacuum at 60 C. to obtain a black powder product as expressed by structural formula (I-a). Referring to FIG. 4, there is shown a .sup.1H-NMR spectrum of the DCPD-derived polyether according to embodiment 2 of the present invention. As shown in the diagram, a 400 MHz .sup.1H-NMR spectrum of polymer (I-a) in DMSO-d.sub.6 deuterated solution shows a characteristic peak of ArOH at 9.4 ppm, proving that polymer (I-a) was successfully synthesized.

(34) ##STR00016##

(35) Embodiment 3: 1.00 g (0.00112 mol) of polymer (I-a), 0.8 g (0.001127 mole) of acetic anhydride, 0.01 g of sodium acetate and 10 mL of N, N-dimethyl acetamide (DMAc) were added to a 100 mL three-neck reactor and heated therein in a nitrogen atmosphere to 130 C. to react for 12 hours. Upon completion of the reaction, the resultant solution was introduced into water to precipitate a black solid. Afterward, the black solid was rinsed with methanol and water and then underwent suction filtration. Finally, the resultant filter cake was dried in vacuum at 70 C. to obtain a black solid product expressed by structural formula (I-b). Referring to FIG. 5, there is shown a .sup.1H-NMR spectrum of the DCPD-derived polyether according to embodiment 3 of the present invention. As shown in the diagram, a 400 MHz .sup.1H-NMR spectrum of polymer (I-b) in DMSO-d.sub.6 deuterated solution shows the disappearance of a characteristic peak of ArOH at 9.4 ppm and the appearance of a characteristic peak of CH.sub.3 at 2.2 ppm. Considering the findings, it was confirmed that polymer (I-b) was successfully synthesized.

(36) ##STR00017##

(37) Embodiment 4: 1.00 g (1.12 mmol) of polymer (I-a), 0.345 g (1.12*2 mmole) of methacrylic anhydride, 0.01 g of sodium acetate and 10 mL of DMAc were added to a 100 mL three-neck reactor and heated therein in a nitrogen atmosphere to 80 C. to react for 12 hours. Upon completion of the reaction, the resultant solution was introduced into water to precipitate a black solid. Afterward, the black solid was rinsed with methanol and water and then underwent suction filtration. Finally, the resultant filter cake was dried in vacuum at 70 C. to obtain a black solid product expressed by structural formula (I-c). Referring to FIG. 6, there is shown, a .sup.1H-NMR spectrum of the DCPD-derived polyether according to embodiment 4 of the present invention. As shown in the diagram, a 400 MHz .sup.1H-NMR spectrum of polymer (I-c) in DMSO-d.sub.6 deuterated solution shows a characteristic peak of a benzene ring at 6.0 ppm through 8.2 ppm, a characteristic peak of aliphatic at 1.0 ppm through 2.0 ppm, and a characteristic peak of Ha and Hb at 5.8 and 6.2 ppm, but absence of a characteristic peak of residual OH, proving that the end product has a correct structure.

(38) ##STR00018##

(39) Embodiment 5: 1.00 g (1.12 mmol) of polymer (I-a), 0.204 g (1.12/0.92*1.1 mmole) of 4-vinylbenzyl chloride, 0.17 g (1.12*1.1 mmol) of K.sub.2CO.sub.3 and 10 mL of DMAc were added to a 100 mL three-neck reactor and heated therein in a nitrogen atmosphere to 80 C. to react for 12 hours. Upon completion of the reaction, the resultant solution was introduced into water to precipitate a black solid. Afterward, the black solid was rinsed with methanol and water and then underwent suction filtration. Finally, the resultant filter cake was dried in vacuum at 70 C. to obtain a black solid product expressed by structural formula (I-d). Referring to FIG. 7, there is shown a .sup.1H-NMR spectrum of the DCPD-derived polyether according to embodiment 5 of the present invention. As shown in the diagram, a .sup.1H-NMR spectrum of polymer (I-d) in DMSO-d.sub.6 deuterated solution shows a characteristic peak of a benzene ring at 6.0 ppm through 8.2 ppm and a characteristic peak of aliphatic at 1.0 ppm through 2.0 ppm, a characteristic peak of Ha at 4.9 ppm, and a characteristic peak of Hb and Hc at 5.2 ppm and 5.8 ppm, but absence of a characteristic peak of residual OH, proving that the end product has a correct structure.

(40) ##STR00019##

(41) Embodiment 6: allowing polymer (I-b) to cure commercially-available epoxy resin HP7200. Dimethyl acetamide (DMAc) is used as a solvent for setting the epoxy resin to polymer (I-b) equivalent ratio to 1:1 such that the resultant solution has solids content of 30 wt %. Afterward, 4-dimethylaminopyridine (DMAP), which makes up 0.5 percent of the epoxy resin by weight, was added into an aluminum tray of a diameter of 5 cm. Afterward, the aluminum tray was put in a circulation oven heated stepwise to 100 C. for 12 hours, then 150 C., 180 C., 200 C., and 220 C. each for two hours to undergo stepwise temperature-rising curing. Finally, the epoxy resin was soaked in water to facilitate mold release and thus obtain a brown cured product.

(42) Embodiment 7: embodiment 7 is substantially the same as embodiment 6 but different from embodiment 6 in that embodiment 7 requires replacing polymer (I-b) with polymer (I-c) to obtain a brown cured product by temperature-rising curing.

(43) Embodiment 8: allowing polymer (I-d) to cure itself. Dimethyl acetamide (DMAc) is used as a solvent whereby the resultant polymer (I-d)-containing solution has solids content of 30 wt %. Afterward, tert-butyl cumyl peroxide (TBCP) was added to the aforesaid solution which was then added into an aluminum tray of a diameter of 5 cm. Afterward, the aluminum tray was put in a circulation oven heated stepwise to 100 C. for 12 hours, then 150 C., 180 C., 200 C., and 220 C. each for two hours to undergo stepwise temperature-rising curing. Finally, the epoxy resin was soaked in water to facilitate mold release and thus obtain a brown cured product.

(44) The glass transition temperatures of the cured products in embodiment 6, embodiment 7, and embodiment 8 were measured with a dynamic mechanical analyzer (DMA) and a dynamic mechanical analyzer (DMA). Furthermore, the cured products were each cut into samples each 20 mm long, 10 mm wide, and 2 mm thick, and then each sample was heated up at a speed of 5 C./min and a frequency of 1 Hz to measure the storage modulus E thereof and plot the Tan curve thereof. Referring to FIG. 8, there is shown the findings in dynamic mechanical analysis (DMA) of the DCPD-derived polyether according to an embodiment of the present invention. As shown in the diagram, the glass transition temperatures in embodiment 6, embodiment 7, and embodiment 8 are 254 C., 267 C., and 289 C., respectively. Embodiment 7 requires double-bond cross-linking and thus features a reticular structure more compact than embodiment 6 and a higher glass transition temperature than embodiment 6. Embodiment 8 features a higher glass transition temperature than embodiments 6, 7 after self-curing.

(45) The glass transition temperatures of the cured products in embodiment 6, embodiment 7, and embodiment 8 were measured with a thermomechanical analyzer (TMA). Each sample was heated up at a speed of 5 C./min. Referring to FIG. 9, there is shown the findings in thermomechanical analysis (TMA) of the DCPD-derived polyether according to an embodiment of the present invention. As shown in the diagram, the glass transition temperatures in embodiment 6, embodiment 7, and embodiment 8 are 212 C., 245 C., and 258 C., respectively, and the coefficients of thermal expansion (CTE) from 50 C. to 150 C. in embodiment 6, embodiment 7, and embodiment 8 are 49 ppm/ C., 47 ppm/ C., and 49 ppm/ C., respectively, showing that the trend of the glass transition temperatures conforms with DMA.

(46) The material thermal stability of the cured products in embodiment 6, embodiment 7, and embodiment 8 was analyzed with a thermogravimetric analyzer (TGA). Referring to FIG. 10, there is shown the findings in thermogravimetric analysis (TGA) of the DCPD-derived polyether according to an embodiment of the present invention. As shown in the diagram, the thermal decomposition 5% temperature (Td5%) in embodiment 6, embodiment 7, and embodiment 8 are 383 C., 405 C., and 426 C., respectively, and the char yield (CY) at 800 C. in the presence of nitrogen in embodiment 6, embodiment 7, and embodiment 8 are 32%, 26%, and 41%, respectively.

(47) Table 1 shows the findings of the thermal analysis of the cured products in embodiment 6, embodiment 7, and embodiment 8, indicating that, upon introduction of a phosphorus group, the cured products still have a satisfactory thermal stability. Finally, the cured products in embodiment 6, embodiment 7, and embodiment 8 underwent UL-94 flammability combustion test and thus were found to be of V-0 rating, showing that the cured product becomes more non-flammable because of introduction of phosphorus-containing DOPO.

(48) TABLE-US-00001 TABLE 1 Tg ( C.) Tg ( C.) CTE Td5% CY Embodiment (DMA) (TMA) (ppm/ C.) ( C.) (%) Embodiment 6 254 212 49 383 32 Embodiment 7 267 245 47 405 26 Embodiment 8 289 258 49 426 41

(49) Regarding analysis of electrical characteristics, dielectric constant (Dk) and dissipation factor (Df) of the cured products in embodiment 6, embodiment 7, and embodiment 8 were measured, and the findings are shown in Table 2. The cured product in embodiment 8 has the least dielectric constant (Dk=2.65) and dissipation factor (Df=0.0095), because it undergoes double-bond cross-linking and thus has a hydrophobic, low-polarity long carbon chain. Similarly, compared with the cured product in embodiment 6, the cured product in embodiment 7 has a hydrophobic, low-polarity long carbon chain and thus a smaller dielectric constant and dissipation factor than embodiment 6. The products each have a dielectric constant of less than 2.76 when cured, thereby meeting the present requirement of high-frequency substrates.

(50) TABLE-US-00002 TABLE 2 Embodiment Dk (1 GHz) Df (1 GHz) Embodiment 6 2.76 0.0112 Embodiment 7 2.72 0.0104 Embodiment 8 2.65 0.0095

(51) After undergoing curing with an epoxy resin, a DCPD-derived polyether of the present invention has low-k characteristics and satisfactory glass transition temperature and is non-flammable to not only serve as an epoxy resin curing agent but also cures itself. The DCPD-derived polyether of the present invention not only has low-k characteristics, high thermal properties, and non-flammability but is also applicable to substrates of printed circuit boards, thereby having wide applications.

(52) The above embodiments are illustrative of the features and effects of the present invention rather than restrictive of the scope of the substantial technical disclosure of the present invention. Persons skilled in the art may modify and alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, the scope of the protection of rights of the present invention should be defined by the appended claims.