Halogen-free epoxy resin composition having low dielectric loss

Abstract

The present invention discloses a halogen-free epoxy resin composition having low dielectric loss, comprises: (A) 100 parts by weight of an epoxy resin; (B) 10-30 parts by weight of a DOPO modified curing agent; (C) 1-10 parts by weight of benzoxazine resin; (D) 60-90 parts by weight of an active ester compound; (E) 20-50 parts by weight of a flame retardant; and (F) 0.5-10 parts by weight of a curing accelerator. The halogen-free epoxy resin composition uses active ester as a curing agent of the epoxy resin to ensure that the hardening product has characteristics such as low dielectric constant (Dk), low dielectric loss (Df), high heat resistance, low water absorption, flame retardant and halogen-free. The halogen-free epoxy resin composition of the present invention is used for manufacturing semi-cured prepregs or resin-coated films, and is applied toward manufacturing metal clad laminates and printed circuit boards.

Claims

1. A halogen-free epoxy resin composition having low dielectric loss, comprises: (A) 100 parts by weight of an epoxy resin; (B) 10-30 parts by weight of a DOPO curing agent; (C) 1-10 parts by weight of benzoxazine resin; (D) 60-90 parts by weight of an active ester; (E) 20-50 parts by weight of a flame retardant; and (F) 0.5-10 parts by weight of a curing accelerator, wherein the active ester contains at least two active ester groups; wherein the active ester has the following Formula A: ##STR00015## and wherein the functional groups ##STR00016## may be substituted by naphthol, biphenol, bisphenol A, bisphenol F or bisphenol S structures, X is benzene ring or naphthalene ring, 1, m, k=0 or 1, n=0.25-2.

2. The halogen-free epoxy resin composition having low dielectric loss of claim 1, wherein the epoxy resin is selected from one of the group consisting of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, phenol novolac epoxy resin, cresol novolac epoxy resin, bisphenol A novolac epoxy resin, bisphenol F novolac epoxy resin, diphenylenthylene epoxy resin, epoxy resin having triazine skeleton, epoxy resin having fluorene skeleton, triphenylmethane epoxy resin, biphenyl epoxy resin, xylylene epoxy resin, biphenyl aralkyl epoxy resin, naphthalene epoxy resin, dicyclopentadiene epoxy resin, alicyclic epoxy resin, diglycidyl ether having polyfunctional phenols and fused ring aromatics, trifunctional and tetrafunctional epoxy resin with three or four in the molecule, and phosphorus-containing epoxy resin.

3. The halogen-free epoxy resin composition having low dielectric loss of claim 1, wherein the DOPO curing agent is selected from one material of the group consisting of 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and its derivatives.

4. The halogen-free epoxy resin composition having low dielectric loss of claim 1, wherein the benzoxazine resin is selected from one resin of the group consisting of bisphenol F (BPF) benzoxazine, bisphenol S (BPS) benzoxazine, diaminodiphenylmethane (DDM) benzoxazine, oxydianiline (ODA) benzoxazine and polybenzoxazine with polyimide.

5. The halogen-free epoxy resin composition having low dielectric loss of claim 1, wherein the flame retardant is selected from one flame retardant having the following structure formulas of the group consisting of: ##STR00017## wherein R is selected from a group consisting of: ##STR00018## ##STR00019## wherein X is selected from a group consisting of: ##STR00020## Y is selected from a group consisting of: ##STR00021## and; n is an integer between 0-500; ##STR00022## wherein X is selected from a group consisting of: ##STR00023## A is selected from a group consisting of: ##STR00024## when n is 0, Y is: ##STR00025## when n is an integer between 1-500, Y selected from a group consisting of: ##STR00026## A is selected from a group consisting of: ##STR00027## and Z is selected from a group consisting of: ##STR00028##

6. The halogen-free epoxy resin composition having low dielectric loss of claim 1, further comprising an additional flame retardant compound selected from one of a group consisting of resorcinol dixylenylphosphate, melamine polyphosphate, (tri (2-carboxyethyl) phosphine (TCEP), trimethyl phosphate (TMP), tri (isopropyl chloride) phosphate, dimethyl methyl phosphonate (DMMP), bisphenol diphenyl phosphate, ammonium polyphosphate), hydroquinone bis-(diphenyl phosphate), and bisphenol A bis-(diphenylphosphate).

7. The halogen-free epoxy resin composition having low dielectric loss of claim 1, wherein the curing accelerator is selected from one of the group consisting of imidazoles, boron trifluoride amine complexes, 2-ethyl-4-methylimidazole, 2-methylimidazole, 2-phenyl-1H-imidazole, ethyltriphenyl phosphonium chloride, triphenylphosphine, and 4-dimethylaminopyridine.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) In cooperation with attached drawings, the technical contents and detailed description of the present invention are described thereinafter according to a preferable embodiment, being not used to limit its executing scope. Any equivalent variation and modification made according to appended claims is all covered by the claims claimed by the present invention.

(2) In order to make the above mentioned and other objects, features and advantages become apparent from, embodiments are detailed in the following: The resin compositions illustrated in embodiments 1 to 5 (E1 to E5) are respectively listed in Table One, and the resin compositions illustrated in comparative embodiments 1 to 4 (C1 to C4) are respectively listed in Table Three.

(3) The resin compositions illustrated in above mentioned embodiments 1 to 5 and the comparative embodiments 1 to 4 are uniformly mixed in stirring tank by batches then put in an impregnation tank. The glass fiber cloth is impregnated in the impregnation tank where the resin compositions are attached to the glass fiber fabric, and then the glass fiber fabric with resin compositions is heated and baked to a semi-cured state in order to obtain semi-cured films.

(4) Take four semi-cured prepregs from the same batch prepared at the same time and two 18 m copper foils, and laminate in an order of one copper foil, four semi-cured prepregs and one copper foil to obtain a metal clad laminate, and then pressed for two hours at 220 C. under vacuum. The four semi-cured prepregs are used as an insulating layer between two copper foils.

(5) Respectively, properties of substrate containing copper foil and substrate without copper foil after etching were measured. The properties measured include glass transition temperature (Tg), copper foil substrate heat resistance (T288), pressure cooker test (PCT) for copper-free substrates after Dip test and moisture absorption, peeling between copper foil and substrates (peel strength, half ounce copper foil, P/S), dielectric constant (Dk, preferably Dk is lower), dielectric loss (Df, preferably Df is lower), flame retardant property (flaming test, UL94, wherein the ranking is V-0>V-1>V-2).

(6) The property measurement results of the substrate made with the resin compositions in the embodiments 1 to 5 are listed in Table Two, and the property measurement results of the substrate made with the resin compositions in the comparative embodiments 1 to 4 are listed in Table Four. Compare the results of the embodiments 1 to 5 in Table Two and the comparative embodiments 1 to 4 in Table Four, the properties of the substrates with composition containing resin compositions and ratios disclosed in the present invention are superior than those made with the comparative embodiments 1 to 4. The embodiments 1 to 5 (E1 to E5) contains active ester, DOPO modified curing agent and benzoxazine resin. The result shows the dielectric loss (Df) decreases as the quantity of the active ester reduces. As shown in E1, substrates containing active ester and benzoxazine resins but without DOPO modified curing agents have high Tg; as shown in E5, substrates with active ester and DOPO modified curing agents but without benzoxazine resins have higher peel strength (P/S) and lower dielectric constant (Dk).

(7) The comparative embodiments 1 to 4 (C1 to C4) uses styrene maleic anhydride (EF60) and benzoxazine resins. The result shows that the heat resistance decreases (Tg, T2288) as quantity styrene maleic anhydride (EF60) increases. According to the results indicated in the embodiments 1 to 5 and the comparative embodiments 1 to 4, the active ester used in the embodiments 1 to 5 according to the present invention effectively improves the overall heat resistance of the resin composition and provide superior low dielectric loss factor (Df).

(8) TABLE-US-00001 TABLE ONE Composition E1 E2 E3 E4 E5 Epoxy resin HP-7200 40 40 40 30 30 NC-3000 60 60 60 70 70 DOPO modified DOPO-BPAN 7 15 23 30 curing agent Benzoxazine resin LZ8280 10 8 5 2 Active ester compound Formula 1 90 85 80 75 70 active ester Flame retardant Formula 1 40 30 5 flame retardant Formula 2 40 5 5 flame retardant Formula 3 40 5 30 flame retardant Flame retardant PX-200 10 10 10 10 10 compound Inorganic filler Flaky silicon 33 40 dioxide Granular silicon 33 40 40 dioxide Curing accelerator BTPB 8 8 8 5 5 2E4MI 2 2 2 5 5 Solvent MEK 45 45 45 50 50 PMA 20 20 20 30 30

(9) TABLE-US-00002 TABLE TWO Properties test Test method E1 E2 E3 E4 E5 Tg DSC 181 178 177 174 172 T288 TMA >60 >60 >60 >60 >60 PCT (dip 1 hr/120 C. >60 >60 >60 >60 >60 minute) P/S (lb/min) Hoz Cu foil 7.8 7.7 7.9 7.8 8.1 Dk 1 GHz 4.15 4.17 4.14 4.1 4.09 Df 1 GHz 0.0068 0.0065 0.0064 0.0061 0.0059 Flammability UL94 V-0 V-0 V-0 V-0 V-0 Others PP appearance Good Good Good Good Good

(10) TABLE-US-00003 TABLE THREE Composition C1 C2 C3 C4 Epoxy resin HP-7200 40 40 40 40 NC-3000 60 60 60 60 Maleic anhydride Styrene maleic 30 25 20 10 curing agent anhydride (SMA), EF60 Benzoxazine resin LZ8280 45 50 50 55 Flame retardant Formula 1 35 10 flame retardant Formula 2 35 10 flame retardant Formula 3 35 10 flame retardant Flame retardant PX-200 10 5 compound TCEP 10 5 TMP 10 5 Inorganic filler Spherical silicon 40 40 40 40 dioxide Curing accelerator 2E4MI 1 1 1 1 Solvent MEK 50 40 30 20 PMA 20 30 40 50

(11) TABLE-US-00004 TABLE FOUR Properties test Test method C1 C2 C3 C4 Tg DSC 158 163 163 166 T288 TMA >30 >30 >50 >60 PCT (dip 1 hr/120 C. >60 >60 >60 >60 minute) P/S (lb/min) Hoz Cu foil 6.1 6.8 6.5 7.1 Dk 1 GHz 4.04 4 3.99 3.93 Df 1 GHz 0.0086 0.008 0.0081 0.0077 Flammability UL94 V-0 V-0 V-0 V-0 Others PP Good Good Good Good appearance

(12) The halogen-free resin composition of the present invention provides low dielectric constant, low dielectric loss, high heat resistance, and high flame retardant property by having particular composition and specific ratio; and is used for manufacturing semi-cured prepreg or resin coated film applied in copper clad substrates and printed circuit boards. In terms of industrial applicability, products developed using the resin composition of the present invention can effectively satisfy the demands in the current market.

(13) The above-mentioned descriptions represent merely the preferred embodiment of the present invention, without any intention to limit the scope of the present invention thereto. Various equivalent changes, alternations, or modifications based on the claims of present invention are all consequently viewed as being embraced by the scope of the present invention.