Preparation and application of dicyclopentadiene-phenol and 2,6-dimethyl phenol copolymer epoxy resin

Abstract

This invention provides a new dicyclopentadiene phenol and 2,6-dimethyl phenol copolymer epoxy resin with excellent heat resistance, low dielectric constant Dk, low dissipation factor Df having the formula 1. Preparation of dicyclopentadiene phenol and 2,6-dimethyl phenol copolymer epoxy resin in two steps: Step 1, reacting (a1) dicyclopentadiene phenol resin represented by formula 2 with (a2) 2,6-dimethyl phenol in the presence of acid catalyst by (a3) aldehyde compounds to synthesize dicyclopentadiene phenol-2,6-dimethyl phenol copolymer, and Step 2, reacting dicyclopentadiene phenol and 2,6-dimethyl phenol copolymer with excess epichlorhydrin under NaOH condition to prepare dicyclopentadiene phenol and 2,6-dimethyl phenol copolymer epoxy resin. When this dicyclopentadiene phenol and 2,6-dimethyl phenol copolymer epoxy resin according to the present invention is substituted into compositions for laminate, they have low dielectric constant, low dissipation factor, and no delamination after longer than 10 minutes 288 C. soldering test and 2 hours pressure cooking test.

Claims

1. A dicyclopentadiene phenol and 2,6-dimethyl phenol copolymer epoxy resin having the following Formula I: ##STR00004## wherein, X is equal to an integer from 1-5, Y is equal to an integer from 1-5, and R represents hydrogen, C.sub.1-C.sub.10 alkyl group, phenyl group, or phenyl hydroxyl group.

Description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(1) The detailed description is provided below to more clearly understand the present invention.

(2) The dicyclopentadiene phenol resin and 2,6-dimethyl phenol copolymer epoxy resin according to the present invention has the most obvious advantage that two resins with the excellent electrical property, such as the dicyclopentadiene phenol epoxy resin and the 2,6-dimethyl phenol formaldehyde epoxy resin, are bonded by grafting reaction, and therefore, the copolymer epoxy resin according to the present invention has better electrical property (low dielectric constant Dk and low dissipation factor Df), heat resistance and Tg property than the above two resins. The dicyclopentadiene phenol resin and the 2,6-dimethyl phenol formaldehyde resin are bonded with aldehyde compounds by the grafting reaction in the present of the acid catalyst, and then epoxidation reaction is performed with the epichlorohydrin to prepare the epoxy resin. Due to the bonding by the grafting reaction, the epoxy resin according to the present invention has more functional cardinal number of epoxy group, higher crosslink density after hardening, and so has better electrical property (low dielectric constant Dk and low dissipation factor Df), heat resistance and Tg property than the above two resins.

(3) Explicitly, the preparation method for the dicyclopentadiene phenol resin and 2,6-dimethyl phenol copolymer epoxy resin according to the present invention comprises two steps: Step 1 (synthesis of dicyclopentadiene phenol resin and 2,6-dimethyl phenol copolymer phenolic resin): add 1 mole phenolic hydroxyl group (phenolic group OH) of (a1) dicyclopentadiene phenol resin and (a2) 2,6-dimethyl phenol 12.5 mole into the solvent with intermediate boiling point and low water solubility (boiling point >110 C.), add the acid catalyst, heat to 95-115 C., dissolve 0.8-1.5 mole aldehyde compound in water to prepare 20-50% aqueous solution of aldehyde compound (if the aldehyde compound is liquid, do not prepare the aqueous solution), dropwise add the aqueous solution into the above reaction mixture, react with the aqueous solution of aldehyde compound at 95-115 C. for 1-6 h. The common acid catalyst comprises methanesulfonic acid (MSA), p-toluenesulfonic acid (PTSA), oxalic acid, hydrochloric acid and the like. The use level of the acid catalyst is 0.5-5% of the use level of the dicyclopentadiene phenol resin, and the aldehyde compound comprises formaldehyde, acetaldehyde, glyoxal, benzaldehyde and the like. In the reaction process, the removal of the water may result in the full reaction of the aldehyde compound, and addition of the solvent is to remove the water by co-boiling with the water and remove the aqueous phase by phase separation. The solvent is selected form methyl isobutyl ketone (MIBK), methylbenzene and other solvent with intermediate boiling point and low water solubility. The use level of the solvent is 5-20% of the use level of the dicyclopentadiene phenol resin. After dropwise addition and reaction, perform ripening reaction for 30 min-2 h. After the reaction, neutralize the acid catalyst with alkali. The alkali is not limited, including common industrial alkali, such as sodium hydroxide, potassium hydroxide, amine and the like. After neutralization to pH 6-7, heat to 175-185 C. to remove the solvent and 2,6-dimethyl phenol. After 175-185 C. is reached, slowly reduce vacuum degree to prevent suddenly boiling till vacuum degree <5 torr. Under the condition of vacuum degree <5 torr, maintain 175-185 C. for 1 h. continuously add the solvent such as the methyl isobutyl ketone (MIBK), the methylbenzene and so on, add water for desalination and washing, and obtain the dicyclopentadiene phenol resin and the 2,6-dimethyl phenol copolymer phenolic resin after filtration, removal of the solvent,

(4) Step 2 (synthesis of icyclopentadiene phenol and 2,6-dimethyl phenol copolymer epoxy resin): reacting the dicyclopentadiene-phenol and 2, 6 dimethyl phenol copolymer prepared in Step 1 with excess epichlorohydrin in the present of sodium hydroxide (NaOH) to prepare dicyclopentadiene phenol and 2, 6 dimethyl phenol copolymer epoxy resin, as shown in Steps (1)-(5). (1) pre-reaction: add the dicyclopentadiene phenol resin and 2,6-dimethyl phenol copolymer phenolic resin and the epichlorohydrin (ECH), the equivalence ratio of which is 1:1-8, into a cosolvent, the use level of which is 10-40% of the dicyclopentadiene phenol resin and the 2,6-dimethyl phenol copolymer phenolic resin. The cosolvent comprises propylene glycol monomethyl ether (PM) or alcohol. Add 49.5% NaOH. The equivalence ratio of the dicyclopentadiene phenol resin and 2,6-dimethyl phenol copolymer phenolic resin to NaOH is 1:0.1-0.2; pre-reaction temperature is 50-100 C. and pre-reaction time is 2-4 h. (2) Main reaction: dropwise add the 49.5% NaOH into the reaction mixture at 0.77-0.97:1 equivalence ratio of NaOH to the dicyclopentadiene phenol resin and 2,6-dimethyl phenol copolymer phenolic resin; reaction temperature is 60-65 C., vacuum degree is 160-190 torr and dropwise addition time is 2-5 h, and during the main reaction, remove the water from the reaction system by co-boiling of water and ECH, and return the ECH on the low layer to the system by phase separation in the phase separating barrel, and discharge the water layer. (3) Removal of epichlorohydrin: remove the excess epichlorohydrin ECH at 160 C. temperature and vacuum degree <5 torr. (4) Refining reaction: add the solvent to prepare 30-50% solid content of resin solution, add 20% NaOH for refining reaction; the use level of NaOH=measured value of hydrolyzable chlorine35.540refining coefficient 1.5weight of resin0.2; refining reaction temperature is 70-90 C., and refining reaction time is 1-3 h. (5) After the reaction, add the water for desalination and liquid separation, and filter the resin solvent after neutralizing and washing the separated liquid, and obtain the dicyclopentadiene phenol and 2,6-dimethyl phenol copolymer epoxy resin according to the present invention after removal of the solvent.

(5) More detailed description of the preparation method for dicyclopentadiene phenol and 2,6-dimethyl phenol copolymer epoxy resin according to the present invention, for example, comprising the above Steps 1 and 2. Step 1: add 1 mole phenolic hydroxyl group (phenolic group OH) of (a1) dicyclopentadiene phenol resin and (a2) 2,6-dimethyl phenol 1-2.5 mole into the solvent with intermediate boiling point and low water solubility (boiling point >110 C.), add the acid catalyst, heat to 95-115 C., dissolve 0.8-1.5 mole aldehyde compound in water to prepare 20-50% aqueous solution of aldehyde compound (if the aldehyde compound is liquid, do not prepare the aqueous solution), dropwise add the aqueous solution into the above reaction mixture. To achieve the high percent conversion and high reaction rate in the reaction process, remove water by separating the water using the solvent with intermediate boiling point and low water solubility and phase in the phase separating barrel and discharging the water layer, and return the ECH on the low layer to the system. Dropwise add the aqueous solution of aldehyde compound to achieve better reaction efficiency and more complete reaction. The reaction in this step may cause two results: first, the dicyclopentadiene phenol resin is bonded through reacting the aldehyde with its dicyclopentadiene-phenol or the aldehyde with the 2,6-dimethyl phenol with; second, the 2,6-dimethyl phenol is bonded through reacting the aldehyde with its 2,6-dimethyl phenol. The weight average molecular weight of the prepared product has positive correlation with the use level of the aldehyde compound. The use level of the aldehyde compound is the total equivalent weight of the dicyclopentadiene phenol resin and the 2, 6 dimethyl phenol, and the equivalent weight of the added aldehyde compound is preferably 0.8-1.2.

(6) Step 2: synthesis of the dicyclopentadiene-phenol and 2,6-dimethyl phenol copolymer phenolic resin obtained in Step 1 into the dicyclopentadiene phenol and 2,6-dimethyl phenol copolymer epoxy resin under common epoxidation condition, i.e. epoxidation reaction with the excess epichlorohydrin in the present of sodium hydroxide to prepare the dicyclopentadiene-phenol and 2,6-dimethyl phenol copolymer phenolic resin.

(7) The preferred embodiment of the present invention is detailed by the following embodiments.

(8) Embodiment A: (Synthesis of dicyclopentadiene phenol and 2,6-dimethyl phenol copolymer epoxy Resin A)

(9) Mix and heat dicyclopentadiene phenol resin (Nan Ya Plastics Corporation, NPEH-772L, softening point 85 C.) 170 g (1 mole phenolic hydroxyl group), 2,6-dimethyl phenol 170 g, solvent methyl isobutyl ketone (MIBK) 30 g, catalyst methanesulfonic acid MSA 1.7 g to 107 C., react for 3.5 h after dropwise adding 23% formaldehyde solution 130 g at 107 C., and perform the ripening reaction for 1 h at 107 C. After the reaction, add 0.8 g 49.5% aqueous solution NaOH to neutralize till pH=6-7, heat to 140 C. for dehydration, and continuously heat to 185 C. and slowly reduce the vacuum degree to 5 torr. After the temperature and the vacuum degree reaches set value 185 C. and 5 torr, maintain the temperature and the vacuum degree for 1 h. Add the solvent methyl isobutyl ketone 550 g after cooling and vacuum breakage, stir for 60 min at 80 C., add water 50 g, stand for layering at 80 C., remove the saline layer at lower layer; add water 50 g for washing, stand for layering at 80 C., remove the water layer at lower layer, and repeatedly wash for 1 time. After filtration of the solution, dehydrate at 120 C., heat to 180 C., reduce the vacuum degree to less than 5 torr, and remove the solvent methyl isobutyl ketone (MIBK) to obtain dicyclopentadiene-phenol and 2,6-dimethyl phenol copolymer phenolic resin A with 99.5% yield and quality situation: average molecular weight Mw2500, softening point 126 C., equivalent weight of phenolic hydroxyl group 150 g/eq.

(10) Mix and heat dicyclopentadiene-phenol and 2,6-dimethyl phenol copolymer resin phenolic resin A 150 g, epichlorohydrin 555 g, and propylene glycol monomethyl ether PM 166 g to 60 C., add 49.5% NaOH 12.1 g for 3 h pre-reaction; dropwise add 49.5% NaOH 66 g into the mixed solution for main reaction at temperature 62 C. and vacuum degree 180 torr for 4 h, end the main reaction at 150 C. and 10 torr, dehydrate and remove the ECH after maintaining the above condition for 1 h, add and dissolve the solvent methyl isobutyl ketone 207 g at 80 C. for 30 min, add purified water 196 g, stand 15 min for layering after stirring at 80 C., and remove the water layer at lower layer. According to analysis the hydrolyzable chlorine of the resin is 2500 ppm. Perform refining reaction at 80 C., add 49.5% sodium hydroxide 1.75 g and purified water 2 g to react for 2 h. Continuously add the solvent MIBK 276 g and purified water 50 g, stand for 15 min for phase separation after stirring at 80 C., remove the water layer at lower layer; add purified water 30 g and 10% NaH.sub.2PO.sub.4 20 g, stand for 15 min for phase separation, remove the water layer at lower layer when the pH is 6-7; add purified water 40 g stand for 15 min for phase separation, remove the water layer at lower layer; heat to 117 C. for circulation dehydration for 1 h, heat to 150 C. after filtration of the solution, gradually reduce the vacuum degree to 5 torr, and maintain 150 C. and 5 torr for 1 h to obtain the dicyclopentadiene phenol and 2,6-dimethyl phenol copolymer epoxy resin A according to the present invention.

(11) Quality situation: epoxide equivalent 228 g/eq, hydrolyzable chlorine 240 ppm, weight average molecular weight Mw3500.

(12) Embodiment B: (Synthesis of dicyclopentadiene phenol and 2,6-dimethyl phenol copolymer epoxy Resin B)

(13) Mix and heat dicyclopentadiene phenol resin (Nan Ya Plastics Corporation, NPEH-772L, softening point 110 C.) 180 g (1 mole phenolic hydroxyl group), 2,6-dimethyl phenol 170 g, solvent methyl isobutyl ketone (MIBK) 30 g, catalyst methanesulfonic acid MSA 1.7 g to 107 C., react for 3.5 h after dropwise adding 23% formaldehyde solution 130 g at 107 C., and perform the ripening reaction for 1 h at 107 C. After the reaction, add 0.8 g 49.5% aqueous solution NaOH to neutralize till pH=6-7, heat to 140 C. for dehydration, and continuously heat to 185 C. and slowly reduce the vacuum degree to 5 torr. After the temperature and the vacuum degree reaches set value 185 C. and 5 torr, maintain the temperature and the vacuum degree for 1 h. Add the solvent methyl isobutyl ketone 550 g after cooling and vacuum breakage, stir for 60 min at 80 C., add water 50 g, stand for layering at 80 C., remove the saline layer at lower layer, add water 50 g for washing, stand for layering at 80 C., remove the water layer at lower layer, and repeatedly wash for 1 time. After filtration of the solution, dehydrate at 120 C., heat to 180 C., reduce the vacuum degree to less than 5 torr, and remove the solvent methyl isobutyl ketone (MIBK) to obtain dicyclopentadiene-phenol and 2,6-dimethyl phenol copolymer phenolic resin B with 99.5% yield and quality situation: average molecular weight Mw2800, softening point 129 C., equivalent weight of phenolic hydroxyl group 154 g/eq.

(14) Mix and heat dicyclopentadiene-phenol and 2,6-dimethyl phenol copolymer resin phenolic resin B 154 g, epichlorohydrin 555 g, and propylene glycol monomethyl ether PM 166 g to 60 C., add 49.5% NaOH 12.1 g for 3 h pre-reaction for; dropwise add 49.5% NaOH 66 g into the mixed solution for main reaction at temperature 62 C. and vacuum degree 180 torr for 4 h, and end the main reaction at 150 C. and 10 torr, dehydrate and remove the ECH after maintaining the above condition for 1 h, add and dissolve the solvent methyl isobutyl ketone 207 g at 80 C. for 30 min, add purified water 196 g, stand 15 min for layering after stirring at 80 C., and remove the water layer at lower layer. According to analysis the hydrolyzable chlorine of the resin is 2200 ppm. Perform the refining reaction at 80 C., add 49.5% sodium hydroxide 1.70 g and purified water 2 g to react for 2 h. Continuously add the solvent MIBK 276 g and purified water 50 g, stand for 15 min for phase separation after stirring at 80 C., remove the water layer at lower layer; add purified water 30 g and 10% NaH.sub.2PO.sub.4 20 g, stand for 15 min for phase separation, remove the water layer at lower layer when the pH is 6-7; add purified water 40 g stand for 15 min for phase separation, remove the water layer at lower layer; heat to 117 C. for circulation dehydration for 1 h, heat to 150 C. after filtration of the solution, gradually reduce the vacuum degree to 5 torr, and maintain 150 C. and 5 torr for 1 h to obtain the dicyclopentadiene phenol and 2,6-dimethyl phenol copolymer epoxy resin B according to the present invention.

(15) Quality situation: epoxide equivalent 232 g/eq, hydrolyzable chlorine 210 ppm, weight average molecular weight Mw3800.

(16) See Table 1 for the physical properties of the copper-clad plate prepared in Embodiments 1-5

(17) In Embodiments 1-5, the dicyclopentadiene phenol and 2,6-dimethyl phenol copolymer epoxy resin according to the present invention is used as the component of the resin varnish with good heat resistance and low dielectric constant to prepare the glass fiber substrate. See Table 1 for the compositions of the resin varnish. For example, preparation of the glass fiber substrate by 65% resin varnish with solid content adjusted by the solvent, such as propylene glycol monomethyl ether (PM), or butanone, or acetone, in known method: dip 7628 glass fibre cloth in the above resin solution, dry for several minutes at 170 C. (including temperature dipping machine), adjust the melt viscosity of the dried dipping sheet by controlling the drying time, the minimum of which is 4000-10000 poise, finally overlap 8 dipping sheets between two 35-um copper clad layer by layer, and at 25 kg/cm.sup.2 pressure and temperature rise control order:

(18) 85 C..fwdarw.85 C..fwdarw.200 C..fwdarw.200 C..fwdarw.130 C.

(19) 20 min 30 min 120 min slowly cooling
To obtain 1.6 mm copper clad laminates after hot-pressing.

(20) TABLE-US-00001 TABLE 1 Composition of varnish used and physical property of glass fiber substrate prepared in embodiment Embodiment Embodiment Embodiment Embodiment Embodiment Item 1 2 3 4 5 Dicyclopentadiene phenol 100 80 85 75 and 2,6-dimethyl phenol copolymer epoxy resin Embodiment A Dicyclopentadiene phenol 100 and 2,6-dimethyl phenol copolymer epoxy resin Embodiment B Benzaldehyde-phenol 25 multifunctional group epoxy resin Nan Ya Plastics Corporation NPPN-433 EEW240 g/eq Phenolic resin Nan Ya 10 10 10 Plastics Corporation NPEH-710H OH 105 g/eq Melamine-phenol novolac 5 5 6.3 5 5 SD-1817 OH 80 g/eq Phosphorus hardening 21 21 21 21 21 agent Shina LC950 OH 340 g/eq Active ester hardening 30 30 50 30 agent DICHPC8000 OH 223 g/eq Additive-type phosphorus 16 16 20 18 16 fire retardant Dazhong SPB-100 Styrene-maleic anhydride 50 copolymer SMA Bisphenol F BX, 40 benzoxazine Nan Ya Plastics Corporation NPEX-235 Polyphenyl ether PPE 15 sabic MX-9000 Filler SiO2 98 98 106 104 98 Accelerant 2MI/DMF 0.03 0.03 0.02 0.025 0.03 Solvent PM or MEK 150 150 163 160 150 Tg C. 176 181 180 178 173 Dk (3G) 4.20 4.20 4.21 4.15 4.23 Df (3G) 0.006 0.0065 0.0068 0.0055 0.007 T-288 (copper-bearing) >60 >60 >60 >60 >60 heat resistance (minute) T288 solder heat >10 >10 >10 >10 >10 resistance (minute)

COMPARABLE EXAMPLES 1-3

(21) Without use of the dicyclopentadiene phenol and 2,6-dimethyl phenol copolymer epoxy resin according to the present invention, the other epoxy resin with low dielectric constant is used as the comparable examples, the composition of which is given in Table 2. The benzaldehyde-phenol epoxy resin (Nan Ya Plastics Corporation NPPN-433) is used in the comparable example 1, the 2,6-dimethyl phenol phenolic aldehyde epoxy resin (Nan Ya Plastics Corporation NPPN-260) is used in the comparable example 2, and the dicyclopentadiene-phenol epoxy resin (Nan Ya Plastics Corporation NPPN-272H) is used in the comparable example 3.

(22) TABLE-US-00002 TABLE 2 Composition of varnish used and physical property of glass fiber substrate prepared in comparable example Comparable Comparable Comparable Item example 1 example 2 example 3 Dicyclopentadiene-phenol 100 epoxy resin Nan Ya Plastics Corporation NPPN-272H EEW270 g/eq 2,6-dimethyl phenol formalde- 100 hyde epoxy resin Nan Ya Plastics Corporation NPPN- 260 EEW198 g/eq Benzaldehyde-phenol func- 100 tional group epoxy resin Nan Ya Plastics Corporation NPPN-433 EEW240 g/eq Melamine-phenol 5.5 6 6.5 novolacSD-1817OH 80 g/eq Phenolic resin Nan Ya 10 10 10 Plastics Corporation NPEH- 710H OH 105 g/eq Phosphorus hardening agent 20 22 22 ShinaLC950 OH 340 g/eq Active ester hardening agent 30 30 30 DICHPC8000 OH 223 g/eq Additive-type phosphorus fire 16 18 20 retardant Dazhong SPB-100 filler SiO2 98 98 98 Accelerant 2MI/DMF 0.05 0.04 0.04 Solvent PM or MEK 150 150 150 Tg C. 170 153 162 Dk (3G) 4.48 4.29 4.30 Df (3G) 0.0083 0.0068 0.0072 T-288 (copper-bearing) >60 27 32 heat resistance (minute) T288 solder heat >10 >10 >10 resistance (minute)

(23) According to the above testing results, the glass fiber substrate prepared by substituting the dicyclopentadiene phenol and 2,6-dimethyl phenol copolymer epoxy resin according to the present invention into the formula has lower dielectric constant Dk and dissipation factor Df that those prepared from the benzaldehyde-phenol epoxy resin in the comparable example 1, the 2,6-dimethyl phenol in the comparable example 2 and the dicyclopentadiene-phenol epoxy resin in the comparable example 3, and after substituting the dicyclopentadiene phenol and 2, 6 dimethyl phenol copolymer epoxy resin according to the present invention into the formula, Tg is higher than that of those prepared in the comparable examples 1-3.

(24) 1. Water Absorption Test (PCT for 2 h)

(25) Testing method: cut the etched substrate into 5 cm.sup.2 square test sheets, after baking for 2 hr at 105 C. in a oven, place the test sheet in a pressure cooker at 2atm120 C. for 120 min, and record the weight difference of the test sheet before and after the PCT, which is divided by the initial weight of the test sheet to obtain the water absorption.

(26) 2. 288 Solider Heat Resistance ((PCT for 2 h)

(27) Testing method: dipping the test sheet passing PCT in 288 C. in a soldering furnace, and record the delamination time.

(28) 3. T-288 Heat Resistance (Copper-Bearing)

(29) Analyzed by a thermal mechanical analyzer. Testing method: cut copper clad laminates into 6.35 mm.sup.2 square test sheets and place the test sheet on the test deck of the thermal mechanical analyzer after baking in the oven at 105 C. for 2 h, heat at 10 C./min till 288 C. after zeroing, maintain 288 C., and record the delamination time of the copper clad laminates.

(30) 4. Dielectric Constant Test:

(31) Testing method: cut the substrate without the copper clad into 5cm5cm square test sheets, and after baking in the oven at 105 C. for 2 h, measure the thickness by a thickness gauge, and place the test sheet in the impedance analyzer (Agilent E4991A) to obtain the average dielectric constant Dk of 3 points

(32) 5. Dissipation Factor Test:

(33) Testing method: cut the substrate without the copper clad into 5cm5cm square test sheets, and after baking in the oven at 105 C. for 2 h, measure the thickness by a thickness gauge, and place the test sheet in the impedance analyzer (Agilent E4991A) to obtain the average dissipation factor Dk of 3 points

(34) 6. Glass-Transition Temperature Test:

(35) Analyzed by a differential scanning calorimeter (DSC), and temperature rise rate 20 C./min.

(36) 7. Molecular Weight Mw:

(37) Analyzed by gel chromatography GPC and corrected by the polystyrene with standard molecular weight

SYMBOL DESCRIPTION

(38) No