Halogen free resin composition and prepreg and laminated board prepared therefrom

Abstract

The present invention relates to a halogen-free resin composition and a prepreg and a laminated board prepared therefrom. The halogen-free resin composition contains the following components in parts by weight: 50-100 parts of an epoxy resin; 20-70 parts of benzoxazine; 5-40 parts of a polyphenyl ether; 5-40 parts of allyl benzene-maleic anhydride; 10-60 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 laminated board prepared from the halogen-free resin composition have comprehensive performances such as a low dielectric constant, a low dielectric loss, an excellent flame retardance, heat resistance, cohesiveness and moisture resistance, etc., and are suitable for use in a halogen-free high multilayer circuit board.

Claims

1. A halogen-free resin composition, comprising in parts by weight: from 50 to 100 parts of an epoxy resin, from 20 to 70 parts of benzoxazine, from 5 to 40 parts of a polyphenyl ether, from 5 to 40 parts of allylbenzene-maleic anhydride, from 10 to 60 parts of a halogen-free flame retardant, from 0.2 to 5 parts of a curing accelerator, and from 20 to 100 parts of a filler; wherein the allylbenzene-maleic anhydride has the following chemical structural formula ##STR00006## wherein x is any one selected from the group consisting of 1-4, 6 and 8; n is any one selected from the group consisting of 1-12; both x and n are integers.

2. The halogen-free resin composition according to claim 1, wherein the epoxy resin is any one selected from the group consisting of bisphenol-A epoxy resin, bisphenol-F epoxy resin, biphenyl epoxy resin, alkyl novolac epoxy resin, dicyclopentadiene epoxy resin, bisphenol-A novolac epoxy resin, o-cresol novolac epoxy resin, phenol novolac epoxy resin, trifunctional epoxy resin, tetrafunctional epoxy resin, isocyanate-modified epoxy resin, naphthalene epoxy resin and phosphorus-containing epoxy resin, or a mixture of at least two selected therefrom.

3. The halogen-free resin composition according to claim 1, wherein the benzoxazine is any one selected from the group consisting of fluorinated benzoxazine resin, aliphatic benzoxazine resin and dicyclopentadiene benzoxazine resin, or a mixture of at least two selected therefrom.

4. The halogen-free resin composition according to claim 3, wherein the fluorinated benzoxazine resin is any one selected from the group consisting of the following chemical structural formulae, or a mixture of at least two selected therefrom ##STR00007##

5. The halogen-free resin composition according to claim 3, wherein the aliphatic benzoxazine resin has the following chemical structural formula: ##STR00008## wherein n is 2 or 3.

6. The halogen-free resin composition according to claim 3, wherein the dicyclopentadiene benzoxazine resin has the following chemical structural formula: ##STR00009##

7. The halogen-free resin composition according to claim 1, wherein the polyphenyl ether has a number average molecular weight of 1000-4000.

8. The halogen-free resin composition according to claim 1, wherein the halogen-free flame retardant is any one selected form the group consisting of phosphazene, ammonium polyphosphate, tris(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, or a mixture of at least two selected therefrom.

9. The halogen-free resin composition according to claim 1, wherein the curing accelerator is imidazole accelerator.

10. The halogen-free resin composition according to claim 9, wherein the curing accelerator is any one selected from the group consisting of 2-methylimidazole, undecylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole and 1-cyanoethyl-substituted imidazole, or a mixture of at least two selected therefrom.

11. The halogen-free resin composition according to claim 1, wherein the filler is an organic or inorganic filler.

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

13. The halogen-free resin composition according to claim 11, wherein the filler is an organic filler selected from the group consisting of polytetrafluoroethylene powder, polyphenylene sulfide and polyether sulfone powder, or a mixture of at least two selected therefrom.

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

15. A prepreg prepared from the halogen-free resin composition according to claim 1, wherein the prepreg comprises a matrix material, and the halogen-free resin composition attached thereon after impregnation and drying.

16. A laminate, comprising the prepreg according to claim 15.

17. A printed circuit board, comprising the laminate according to claim 16.

18. The prepreg according to claim 15, wherein the matrix material is a non-woven or woven glass fiber cloth.

19. The halogen-free resin composition according to claim 1, wherein the benzoxazine is any one selected from the group consisting of fluorinated benzoxazine resin and aliphatic benzoxazine resin, or a mixture of at least two selected therefrom.

Description

EMBODIMENTS

(1) The technical solution of the present invention is further stated by the following specific embodiments.

(2) Those skilled in the art shall know that said examples are used to better understand the present invention, rather than any specific restriction to the present invention.

PREPARATION EXAMPLESYNTHESIS OF BENZENE PROPYLENE-MALEIC ANHYDRIDE

(3) Under nitrogen protection and stirring conditions, maleic anhydride monomer and an initiator were added in a medium and dissolved. When being heated to 60-80 C., benzene propylene and a molecular weight modifier were dripped. The stirring continued for 1-8 h after dripping, to obtain a dispersion system of benzene propylene/maleic anhydride polymer particles having a low molecular weight. The dispersion system was centrifuged and dried to obtain a benzene propylene/maleic anhydride alternating copolymer having a low molecular weight. The initiator therein was organic peroxides or azo compounds; the medium was a mixed solution of organic acid alkyl ester and alkane; the molecular weight modifier was vinyl acetate; maleic anhydride and benzene propylene were in a molar ratio of 1:0.90-0.96; the mass concentration sum of maleic anhydride monomer and benzene propylene monomer in the reaction system were 2.0-7.5%; the initiator had a mass concentration of 0.05-0.35%; the molecular weight modifier had a mass concentration of 0.10-0.45%; the organic acid alkyl ester in the mixed solution of organic acid alkyl ester and alkane had a volume percent of 20-80%.

(4) Benzene propylene-maleic anhydride having the following structural formula is obtained:

(5) ##STR00005##
wherein x is any one selected from the group consisting of 1-4, 6 and 8; n is any one selected from the group consisting of 1-12; both x and n are integers.

EXAMPLES

(6) Preparation Method for Copper Clad Laminates

(7) Epoxy resin, benzoxazine, a polyphenyl ether, benzene propylene-maleic anhydride, a halogen-free flame retardant, a curing accelerator, a filler and a solvent were placed in a vessel, stirred and homogeneously mixed to obtain a glue. The solvent was used to adjust the solid content of the solution to 60-70% to obtain a varnish, i.e. the halogen-free composition varnish of the present invention. A 2116 electronic level glass fiber cloth was impregnated with the varnish, oven-dried to obtain a prepreg. Six sheets of 2116 prepregs were covered with electrolytic copper foils having a thickness of 35 m on both sides thereof, vacuum-laminated in a hot press, cured at 190 C. for 120 minutes to obtain copper clad laminates.

(8) The components and contents thereof (in parts by weight) in Examples 1-8 and Comparison Examples 1-5 are shown in Table 1, and the component codes and corresponding component names are shown as follows.

(9) AEpoxy resin

(10) A-1biphenyl epoxy resin: NC-3000-H (Product name from Nippon Kayaku)

(11) A-2dicyclopentadiene epoxy resin: HP-7200H (Product name from Dainippon Ink)

(12) Bbenzoxazine

(13) B-1aliphatic benzoxazine: KAH-F5404 (Product name from Kolon)

(14) B-2fluorinated benzoxazine: KAH-F5301 (Product name from Kolon)

(15) B-3bispheno-F benzoxazine: LZ8280 (Huntsman Advanced Materials)

(16) B-4dicyclopentadiene benzoxazine: LZ8260 (Huntsman Advanced Materials)

(17) C-1polyphenyl ether having a low molecular weight: MX90 (Product name from SABIC Innovative Plastics) having a number average molecular weight of 1000-4000

(18) C-2polyphenyl ether having a high molecular weight: Sabic640-111 (Product name from SABIC Innovative Plastics) having a number average molecular weight of 15000-20000

(19) D-1Benzene propylene-maleic anhydride oligomer in the preparation example

(20) D-2Styrene-maleic anhydride oligomer: SMA-EF40 (Product name from Sartomer)

(21) EHalogen-free flame retardant: phosphorus-containing novolac resin: XZ92741 (Product name from DOW Chemical)

(22) FCuring accelerator: 2E4MZ (Product name from Shikoku Chemicals)

(23) GFiller: molten silica

(24) The processes for preparing copper clad laminates in Examples 1-8 and Comparison Examples 1-5 is the same as that in the examples.

(25) The following methods are used to test the glass transition temperature (Tg), peeling strength (PS), dielectric constant (Dk) and dielectric loss tangent (Df), flame retardancy, dip soldering resistance and water absorption after PCT for 2 hours, and the test results are shown in Table 2.

(26) The performance parameters are tested by the following methods.

(27) AGlass transition temperature (Tg): tested by the differential scanning calorimetry (DSC) according to the DSC method stipulated under IPC-TM-650 2.4.25;

(28) BPeeling strength (PS): testing the peeling strength of the metal cover layer according to the test conditions of after heat stress in the method of IPC-TM-650 2.4.8;

(29) CDielectric constant (Dk) and dielectric loss tangent (Df): testing the dielectric constant (Dk) and dielectric loss tangent (Df) at 1 GHz by the resonance method of strip lines according to IPC-TM-650 2.5.5.5;

(30) DFlame retardancy: tested according to UL-94 standard; and

(31) EDip soldering resistance and water absorption after PCT for 2 hours.

(32) Copper clad laminates were impregnated in the copper etching solution to remove the copper foils on the surface and to evaluate the substrates; the substrates were placed in a pressure pan at 121 C. and 2 atm for 2 hours, and impregnated in a tin stove having a temperature of 288 C. after testing the water absorption; when blistering or splitting takes place in the substrate, the corresponding time was recorded. When blistering or splitting does not take place more than 5 minutes after the substrates were placed in the tin stove, the evaluation was ended.

(33) TABLE-US-00001 TABLE 1 Exam- Exam- Exam- Exam- Exam- Comp. Comp. Comp. Comp. Comp. Example 1 Example 2 Example 3 ple 4 ple 5 ple 6 ple 7 ple 8 Example 1 Example 2 Example 3 Example 4 Example 5 A-1 60 60 60 50 50 60 60 60 A-2 60 60 50 50 50 60 60 B-1 42 42 42 42 70 42 42 B-2 42 20 42 42 B-3 42 B-4 70 C-1 25 25 25 25 25 5 40 40 25 25 25 C-2 25 D-1 5 15 25 40 25 10 40 40 25 25 25 D-2 15 25 E 20 20 20 20 20 10 60 60 20 20 20 20 20 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. G 50 50 50 50 50 20 100 100 50 50 50 50 50

(34) TABLE-US-00002 TABLE 2 Testing items Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Tg (DSC) 185 186 190 197 189 184 195 ( C.) Peeling 1.35 1.35 1.34 1.30 1.32 1.34 1.34 strength (N/mm) Dielectric 3.7 3.7 3.6 3.6 3.7 3.7 3.7 constant (1 GHz) Dielectric 0.0060 0.0059 0.0055 0.0053 0.0060 0.0060 0.0060 loss (1 GHz) Combustibility V-0 V-0 V-0 V-0 V-0 V-0 V-0 PCT (min) >5 >5 >5 >5 >5 >5 >5 PCT 0.34 0.34 0.35 0.36 0.35 0.34 0.33 water absorption Processability Good Good Good Good Good Good Good Testing Comp. Comp. Comp. Comp. Comp. items Example 8 Example 1 Example 2 Example 3 Example 4 Example 5 Tg (DSC) 198 175 185 186 192 187 ( C.) Peeling 1.35 1.35 1.33 1.32 1.45 1.30 strength (N/mm) Dielectric 3.6 3.8 3.7 4.0 4.1 3.8 constant (1 GHz) Dielectric 0.0054 0.0068 0.0065 0.0086 0.010 0.0061 loss (1 GHz) Combustibility V-0 V-0 V-0 V-1 V-0 V-0 PCT (min) >5 >5 >5 >5 >5 >5 PCT 0.34 0.36 0.38 0.40 0.39 0.35 water absorption Processability Good Good Good Good Good Worse

(35) According to Tables 1 and 2,

(36) (1) by comparing Examples 2-3 to Comparison Examples 1-2, it can be seen that the laminates in Examples 2-3 have a lower dielectric constant, dielectric loss and PCT water absorption than those in Comparison Examples 1-2, which shows that using benzene propylene-maleic anhydride in Examples 2-3 can achieve a lower dielectric constant, dielectric loss and PCT water absorption than using styrene-maleic anhydride in Comparison Example 1.
(2) By comparing Examples 3 and 5 to Comparison Example 3, it can be seen that the laminates in Examples 3 and 5 have a higher glass transition temperature, but a lower dielectric constant, dielectric loss and PCT water absorption than that in Comparison Example 3, and a flame retardancy of V-0 level, which shows that using aliphatic benzoxazine and fluorinated benzoxazine respectively in Examples 3 and 5 can achieve a higher glass transition temperature, but a lower dielectric constant, dielectric loss and PCT water absorption, and a higher flame retardancy than using bisphenol-F benzoxazine in Comparison Example 3. According to Examples 7 and 8, it can be seen that using dicyclopentadiene benzoxazine and aliphatic benzoxazine both can achieve a higher glass transition temperature, but a lower dielectric constant, wherein using aliphatic benzoxazine can achieve a higher glass transition temperature, but a lower dielectric constant.
(3) By comparing Example 5 to Comparison Example 4, it can be seen that the laminate in Example 5 has a lower dielectric constant, dielectric loss and PCT water absorption than that in Comparison Example 4, which shows that using polyphenyl ether resin having a low molecular weight in Example 5 can achieve a lower dielectric constant, dielectric loss and PCT water absorption than using no component above in Comparison Example 4. By comparing Example 5 to Comparison Example 5, it can be seen that using polyphenyl ether resin having a high molecular weight results in a worse processability, though their overall performances are quite equivalent to each other.
(4) By comparing Examples 1-4, it can be seen that Example 1 shows a lowest glass transition temperature, but a highest dielectric constant and dielectric loss, and Example 4 shows a highest glass transition temperature, but a lowest dielectric constant and dielectric loss, which shows that the increase of the benzene propylene-maleic anhydride content may increase the glass transition temperature and reduce the dielectric constant and dielectric loss.

(37) According to Examples 1-8, it can be seen that the laminates prepared by using the halogen-free resin composition of the present invention have a dielectric constant which may be controlled at 3.7 or less, a maximum dielectric loss value of just 0.0060, and a PCT water absorption of 0.34-0.36, and may achieve the V-0 standard in the flame retardancy test UL-94. Therefore, while ensuring being halogen-free and the flame retardancy, the laminates have overall performances, such as a low dielectric constant, a low dielectric loss, an excellent flame retardancy, heat resistance, cohesiveness, moisture resistance and the like, and are suitable for use in halogen-free high multilayer circuit boards.

(38) The aforesaid examples are only better examples of the present invention, rather than for limiting the protection scope of the present invention. Thus, equivalent changes or modifications made according to the principles as stated within the protection scope of the present invention application all fall within the protection scope of the present invention application.