HALOGEN-FREE RESIN COMPOSITION AND PREPREG AND LAMINATE PREPARED THEREFROM

Abstract

A halogen-free resin composition and a prepreg and a laminate prepared therefrom. The halogen-free resin composition comprises the following ingredients in parts by weight: 50-100 parts of an epoxy resin, 20-70 parts of benzoxazine, 5-40 parts of polyphenyl ether, 5-30 parts of styrene-maleic anhydride, 5-40 parts of a halogen-free flame retardant, 0.2-5 parts of a curing accelerator, and 20-100 parts of a filler. The prepreg and the laminate, which are manufactured from the halogen-free resin composition, have the comprehensive properties of low dielectric constant, low dielectric loss, excellent heat resistance, adhesive property and wet resistance and the like, and are suitable for being applied to halogen-free high-frequency multilayer circuit boards.

Claims

1-10. (canceled)

11. A halogen-free resin composition, comprising the following components in parts by weight: 50-100 parts of an epoxy resin, at least comprising an epoxy resin having the dicyclopentadiene alkyl structure as shown in the following chemical formula: ##STR00007## 20-70 parts of benzoxazine; 5-40 parts of a polyphenyl ether; 5-30 parts of styrene-maleic anhydride; 5-40 parts of a halogen-free flame retardant; 0.2-5 parts of a curing accelerator; and 20-100 parts of a filler.

12. The halogen-free resin composition of claim 11, wherein the epoxy resin is selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl epoxy resin, alkyl novolac epoxy resin, dicyclopentadiene epoxy resin, bisphenol A type novolac epoxy resin, o-cresol type novolac epoxy resin, phenol type novolac epoxy resin, trifunctional epoxy resin, tetrafunctional epoxy resin, isocyanate modified epoxy resin, naphthalene type epoxy resin and phosphorus-containing epoxy resin, and a mixture of at least two of the foregoing.

13. The halogen-free resin composition of claim 11, wherein the benzoxazine is selected from the group consisting of fluorinated benzoxazine resin, aliphatic benzoxazine resin and dicyclopentadiene benzoxazine resin, and a mixture of at least two of the foregoing.

14. The halogen-free resin composition of claim 11, wherein the benzoxazine is selected from the group consisting of fluorinated benzoxazine resin and aliphatic benzoxazine resin, and a mixture of at least two of the foregoing.

15. The halogen-free resin composition claimed in claim 13, wherein the fluorinated benzoxazine resin is selected from the group of the following chemical formulae, or a mixture of at least two selected therefrom: ##STR00008##

16. The halogen-free resin composition of claim 13, wherein the aliphatic benzoxazine resin has the chemical structural formula of: ##STR00009## wherein n is 2 or 3.

17. The halogen-free resin composition of claim 13, wherein the dicyclopentadiene benzoxazine resin has the chemical structural formula of: ##STR00010##

18. The halogen-free resin composition of claim 11, wherein the polyphenyl ether has a number-average molecular weight of 1000-4000.

19. The halogen-free resin composition of claim 11, wherein the styrene-maleic anhydride has the chemical structural formula of: ##STR00011## wherein x is 1-4, 6 and 8; n is 1-12; x and n both are integers.

20. The halogen-free resin composition of claim 11, wherein the halogen-free flame retardant is selected from the group consisting of phosphazene, ammonium polyphosphate, tri-(2-carboxyethyl)-phosphine, tri-(isopropylchloro)phosphate, trimethyl phosphate, dimethyl-methyl phosphate, resorcinol bis-xylyl phosphate, phosphorus-nitrogen compounds, melamine polyphosphate, melamine cyanurate, tri-hydroxyethyl isocyanurate, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and DOPO-containing novolac resin, and a mixture of at least two of the foregoing.

21. The halogen-free resin composition of claim 11, wherein the curing accelerator is an imidazole accelerator.

22. The halogen-free resin composition of claim 11, wherein the curing accelerator is selected from the group consisting of 2-methylimidazole, undecyl imidazole, 2-ethyl-4-methylimidazole, 2-phenyl-imidazole, and 1-cyanoethyl substituted imidazole, and a mixture of at least two of the foregoing.

23. The halogen-free resin composition of claim 11, wherein the filler is an inorganic or organic filler.

24. The halogen-free resin composition of claim 11, wherein the filler is an inorganic filler selected from the group consisting of aluminum hydroxide, alumina, magnesium hydroxide, magnesium oxide, aluminum oxide, silicon dioxide, calcium carbonate, aluminum nitride, boron nitride, silicon carbide, titanium dioxide, zinc oxide, zirconium oxide, mica, boehmite, calcined talc, talc powder, silicon nitride and calcined kaolin, and a mixture of at least two of the foregoing.

25. The halogen-free resin composition of claim 11, wherein the filler is an organic filler selected from the group consisting of polytetrafluoroethylene powder, polyphenylene sulfide and polyethersulfone powder, and a mixture of at least two of the foregoing.

26. The halogen-free resin composition of claim 11, wherein the filler has a particle size of 0.01-50 m.

27. A prepreg prepared from the halogen-free resin composition of claim 11, wherein the prepreg comprises a matrix material and the halogen-free resin composition attached thereon after impregnation and drying.

28. The prepreg of claim 27, wherein the matrix material is a non-woven or woven glass fiber cloth.

29. A laminate comprising the prepreg of claim 27.

30. A printed circuit board comprising the laminate of claim 29.

Description

EMBODIMENTS

[0044] The technical solution of the present invention will be further described below by the specific embodiments.

[0045] Those skilled in the art shall know that the examples are merely illustrative of the present invention and should not be construed as specifically limiting the present invention.

Preparation Example: Synthesis of Dicyclopentadiene Alkyl Phenol Epoxy Resin

[0046] 270.0 g of p-(1,1,3,3-tetramethyl)butylphenol was added into a four-necked flask (500 mL) equipped with a polytetrafluoroethylene stirrer, a thermometer and a reflux condenser, heated and dissolved in water bath. 1.83 g of boron trifluoride.diethyl ether was added into the 500 mL four-necked flask, and 50.1 g of dicyclopentadiene was added to a dropping funnel to control the dropping speed so that all the dicyclopentadiene was added dropwise within 2 h. The mixture was heated to 100 C., held for 4 h, cooled to room temperature, and then heated to a certain temperature to distill excess dicyclopentadiene and p-(1,1,3,3-tetramethyl)butylphenol. The product is dicyclopentadiene alkyl phenol resin.

[0047] The dicyclopentadiene alkyl phenol resin obtained in the previous step was placed in a four-necked flask. 100.0 g of epichlorohydrin was weighed, added slowly, dissolved and heated. 1 mol of KOH solution having a mass fraction of 33% was added to a dropping funnel, added dropwise within 1 h by controlling the speed. The reaction temperature was controlled at 100 C. After adding dropwise, the temperature was held for 4 h. After cooling, water-washing, heating to 120 C., excessive epichlorohydrin was distilled to obtain the epoxy resin having dicyclopentadiene alkyl phenol structure as shown in the following chemical formula:

##STR00006##

Examples: Process for Preparing Copper Clad Laminates

[0048] An epoxy resin, benzoxazine, a polyphenyl ether, styrene-maleic anhydride, a halogen-free flame retardant, a curing accelerator, a filler and a solvent were put into a container and stirred to make the mixture uniformly into a glue. The solid content of the solution was adjusted to 60%-70% with the solvent to obtain a glue solution, i.e. a glue solution of the halogen-free resin composition of the present invention. A 2116 electronic grade glass cloth was impregnated with the glue, baked into a prepreg by an oven. 6 pieces of 2116 prepregs were covered with electrolytic copper foils having a thickness of 35 m on both sides, vacuum-laminated in a hot press, cured at 190 C. for 120 min to obtain copper clad laminates.

[0049] The components and contents thereof (based on parts by weight) in Examples 1-9 and Comparison Examples 1-5 are shown in Table 1. The component codes and the corresponding component names are shown as follows.

[0050] (A) Epoxy Resin [0051] (A-1) Dicyclopentadiene alkyl phenol epoxy resin synthesized in the preparation example [0052] (A-2) Biphenyl epoxy resin: NC-3000-H (Product name from Nippon Kayaku); [0053] (A-3) Dicyclopentadiene epoxy resin: HP-7200H (Product name from Dainippon Ink and Chemicals)

[0054] (B) Benzoxazine [0055] (B-1) Aliphatic benzoxazine resin: KAH-F5404 (Product name from Kolon) [0056] (B-2) Fluorinated benzoxazine: KAH-F5301 (Product name from Kolon) [0057] (B-3) Bisphenol F benzoxazine: LZ8280 (from Huntsman Advanced Materials) [0058] (B-4) Dicyclopentadiene benzoxazine: LZ8260 (from Huntsman Advanced Materials) [0059] (C-1) Polyphenyl ether having a low molecular weight: MX90 (Product name from SABIC Innovative Plastics) having a number-average molecular weight of 1000-4000; [0060] (C-2) Polyphenyl ether having a high molecular weight: Sabic640-111 (Product name from SABIC Innovative Plastics) having a number-average molecular weight of 15000-20000; [0061] (D) Styrene-maleic anhydride oligomer: SMA-EF40 (Product name from Sartomer) [0062] (E) Phosphorus-containing novolac resin: XZ92741 (Product name from DOW); (F) Curing accelerator: 2E4MZ (Product name from Shikoku Chemicals); [0063] (H) Filler: molten silica.

[0064] The processes for preparing CCLs in Examples 1-9 and Comparison Examples 1-5 are the same as those in the examples.

[0065] The glass transition temperature (Tg), peeling strength (PS), dielectric constant (Dk) and dielectric loss angle tangent (Tg), flame retardancy, dip soldering resistance and water absorption after PCT 2 h of the copper clad laminates prepared in Examples 1-9 and Comparison Examples 1-5 were tested by the following test methods, and the test results are shown in Table 2.

[0066] The performance parameters are tested by the following methods. [0067] A Glass transition temperature (Tg): tested according to the DSC method as stipulated under IPC-TM-650 2.4.25 in accordance with DSC; [0068] B Peeling strength (PS): testing the peeling strength of the metal cover layer under the testing conditions of after thermal stress in the method of IPC-TM-650 2.4.8; [0069] C Dielectric constant (Dk) and dielectric loss angle tangent (DO: testing dielectric constant (Dk) and dielectric loss angle tangent (DO under 1 GHz by the resonance method using a stripe line according to IPC-TM-650 2.5.5.5; [0070] D Flame retardancy: tested according to the UL-94 standard; [0071] E Dip soldering resistance and water absorption after PCT 2 h:

[0072] The copper clad laminate was immersed in a copper etching solution to remove the surface copper foils, and to evaluate the substrate. The substrate was placed in a pressure cooker and treated at 121 C. and 2 atm for 2 hours. After the water absorption was measured, the substrate was immersed in a tin furnace having a temperature of 288 C. The corresponding time was recorded when the substrate is bubbled or split. The evaluation was finished when the substrate had no foaming or stratification in the tin furnace for more than 5 min.

TABLE-US-00001 TABLE 1 Com. Com. Com. Com. Com. Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- ple ple ple ple ple ple ple ple ple ple ple ple ple ple 1 2 3 4 5 6 7 8 9 1 2 3 4 5 A-1 50 65 85 100 85 50 100 100 50 85 100 50 A-2 50 50 A-3 65 B-1 45 45 45 45 45 45 45 45 45 B-2 45 20 B-3 45 B-4 45 70 C-1 25 25 25 25 25 25 25 5 40 25 25 25 C-2 25 D 10 14 20 24 20 10 24 30 5 10 14 20 24 10 E 22 22 22 22 22 22 22 40 5 22 22 22 22 22 F q.s q.s q.s q.s q.s q.s q.s q.s q.s q.s q.s q.s q.s q.s G 50 50 50 50 50 50 50 20 100 50 50 50 50 50

TABLE-US-00002 TABLE 2 Example Example Example Example Example Example Example Example Test items 1 2 3 4 5 6 7 8 Tg(DSC) 178 176 176 177 180 177 175 182 ( C.) Peeling 1.35 1.34 1.33 1.32 1.38 1.34 1.32 1.35 strength (N/mm) Dielectric 3.7 3.7 3.6 3.6 3.6 3.7 3.7 3.6 constant (1 GHz) Dielectric 0.0056 0.0052 0.0050 0.0048 0.0057 0.0053 0.0054 0.0053 loss (1 GHz) Combustibility V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0 PCT >5 >5 >5 >5 >5 >5 >5 >5 (min) PCT water 0.30 0.28 0.28 0.27 0.29 0.28 0.27 0.29 absorption Processability Better Better Better Better Better Better Better Better Com. Com. Com. Com. Com. Example Example Example Example Example Example Test items 9 1 2 3 4 5 Tg(DSC) 178 178 178 174 180 176 ( C.) Peeling 1.34 1.40 1.35 1.32 1.34 1.34 strength (N/mm) Dielectric 3.7 3.9 3.9 4.0 4.1 3.7 constant (1 GHz) Dielectric 0.0054 0.0068 0.0069 0.0085 0.010 0.0058 loss (1 GHz) Combustibility V-0 V-0 V-0 V-1 V-0 V-0 PCT >5 >5 >5 >5 >5 >5 (min) PCT water 0.28 0.36 0.34 0.36 0.34 0.34 absorption Processability Better Better Better Better Better Worse

[0073] It can be seen according to the data in Tables 1 and 2 that, [0074] (1) By comparing Example 1 to Comparison Example 1, it can be found that the dielectric constant, dielectric loss and water absorption of Example 1 were lower than those of Comparison Example 1, indicating that the use of synthesized dicyclopentadiene alkyl phenol epoxy resin in Example 1 can obtain a lower dielectric constant, dielectric loss and PCT water absorption than biphenyl epoxy resin used in Comparison Example 1. [0075] (2) By comparing Example 2 to Comparison Example 2, it can be found that the glass transition temperature in Example 2 was slightly lower than that in Comparison Example 2, and the dielectric constant, dielectric loss and PCT water absorption of Example 2 were lower than those of Comparison Example 2, indicating that the use of synthesized dicyclopentadiene alkyl phenol epoxy resin in Example 2 can obtain a lower dielectric constant, dielectric loss and PCT water absorption than dicyclopentadiene epoxy resin used in Comparison Example 2. [0076] (3) By comparing Examples 3 and 5 to Comparison Example 3, it can be found that the glass transition temperatures in Examples 3 and 5 were higher than that in Comparison Example 3, and the dielectric constant, dielectric loss, and PCT water absorption were all lower than those in Comparison Example 3; the flame retardancy thereof may achieve the V-0 level, indicating that the use of aliphatic benzoxazine and fluorinated benzoxazine in Examples 3 and 5 respectively can obtain higher glass transition temperature, lower dielectric constant, dielectric loss and PCT water absorption and higher flame retardancy than bisphenol F benzoxazine used in Comparison Example 3. According to Examples 4 and 7, it can be seen that the use of dicyclopentadiene benzoxazine and aliphatic benzoxazines can both achieve higher glass transition temperature and lower dielectric constant, wherein using aliphatic benzoxazine can achieve higher glass transition temperature and lower dielectric constant. [0077] (4) By comparing Example 4 to Comparison Example 4, it can be seen that Example 4 can achieve a lower dielectric constant, dielectric loss, and PCT water absorption than Comparison Example 4, indicating that Example 4 can obtain a lower dielectric constant, dielectric loss, and PCT water absorption by adding a polyphenyl ether having a low molecular weight as compared to adding no such component in Comparison Example 4. By comparing Example 1 to Comparison Example 5, it can be seen that, although they had equivalent overall performances, the use of a polyphenyl ether having a high molecular weight resulted in a worse processability. [0078] (5) By comparing Examples 1-4, it can be found that the dielectric loss and PCT water absorption of Example 1 were the highest; the dielectric loss and the PCT water absorption of Example 4 were the lowest, indicating that the dielectric constant, dielectric loss, and PCT water absorption were all reduced along with the increase of the addition amount of dicyclopentadiene alkyl phenol epoxy resin synthesized in the preparation example.

[0079] According to Examples 1 to 9, it was found that the use of dicyclopentadiene alkyl phenol epoxy resin in halogen-free resin compositions can significantly increase the dielectric properties of the substrates as compared to epoxy resins commonly used in the art. The use of styrene-maleic anhydride and benzoxazine for co-curing epoxy compositions, and the addition of a small amount of phosphorus-containing flame retardant and polyphenylene ether having a low molecular weight can improve the flame retardancy, adhesion and moisture resistance of the substrate, resulting in better overall performances, being suitable for the use in halogen-free multi-layer circuit boards, so as to have an important application value.

[0080] Certainly, the above-described examples are merely illustrative examples of the present invention and are not intended to limit the implement scope of the present invention. Therefore any equivalent changes or modifications according to the principles within the patent scope of the present invention are all included in the scope of the present patent.