Halogen-free Flame Retardant Resin Composition, Prepreg and Copper Clad Laminate Prepared Therefrom

Abstract

The present invention relates to a halogen-free flame retardant resin composition, a prepreg and a copper clad laminate prepared therefrom. The composition of the present invention comprises, based on the weight parts of solid components, (A) from 5 to 80 parts by weight of alkylphenol epoxy resin, (B) from 10 to 80 parts by weight of benzoxazine resin, (C) from 2 to 30 parts by weight of styrene maleic anhydride resin, (D) from 1 to 30 parts by weight of a flame retardant, and (E) from 0.5 to 100 parts by weight of an acidic filler having a pH of 2-6. The present invention further provides a prepreg and a copper clad laminate prepared from the halogen-free flame retardant resin composition. While ensuring a higher glass transition temperature and excellent moisture heat resistance, the halogen-free flame retardant resin composition of the present invention effectively improves the dielectric properties and the peel strength stability of the resin composition, and provides the prepregs and copper clad laminates with excellent comprehensive performances.

Claims

1. A halogen-free flame retardant resin composition, characterized in based on the weight parts of solid components, comprising the following components: (A) from 5 to 80 parts by weight of alkylphenol epoxy resin, (B) from 10 to 80 parts by weight of benzoxazine resin, (C) from 2 to 30 parts by weight of styrene maleic anhydride resin, (D) from 1 to 30 parts by weight of a flame retardant, and (E) from 0.5 to 100 parts by weight of an acidic filler having a pH of 2-6.

2. The halogen-free flame retardant resin composition claimed in claim 1, wherein said alkylphenol epoxy resin has the structure as follows ##STR00009## wherein R.sub.1 and R.sub.2 are each independently selected from substituted or unsubstituted linear alkyl or branched alkyl having a carbon atom number of 4-8, n is an integer of 2-20.

3. The halogen-free flame retardant resin composition claimed in claim 1, wherein said benzoxazine resin is anyone selected from the group consisting of bisphenol A type benzoxazine resin, dicyclopentadiene benzoxazine resin, bisphenol F type benzoxazine resin, phenolphthalein benzoxazine resin and MDA type benzoxazine resin, or a mixture of at least two selected therefrom.

4. The halogen-free flame retardant resin composition claimed in claim 1, wherein the styrene chain segment units and maleic anhydride chain segment units have a ratio of 8:1-1:1 in said styrene maleic anhydride resin.

5. The halogen-free flame retardant resin composition claimed in claim 1, wherein said acidic filler is anyone selected from the group consisting of silica powder, quartz powder, mica powder, clay, calcium oxalate and carbon black, or a mixture of at least two selected therefrom.

6. The halogen-free flame retardant resin composition claimed in claim 1, wherein the halogen-free flame retardant resin composition further comprises a non-acidic filler.

7. A process for preparing a halogen-free flame retardant resin composition, wherein comprising adding an acidic filler having a pH of 2-6 into a halogen-free flame retardant resin composition; said halogen-free flame retardant resin composition comprises alkylphenol epoxy resin, benzoxazine resin and styrene maleic anhydride resin.

8. A prepreg comprising the halogen-free flame retardant resin composition claimed in claim 1, or the resin composition prepared according to the process claimed in claim 7.

9. A laminate comprising at least one sheet of the prepreg claimed in claim 8.

10. A printed circuit board comprising at least one sheet of the prepreg claimed in claim 8.

11. The halogen-free flame retardant resin composition claimed in claim 1, wherein said alkylphenol epoxy resin is in an amount of 10-35 parts by weight in the halogen-free flame retardant resin composition

12. The halogen-free flame retardant resin composition claimed in claim 1, wherein said benzoxazine resin is in an amount of 30-65 parts by weight in the halogen-free flame retardant resin composition.

13. The halogen-free flame retardant resin composition claimed in claim 1, wherein said styrene maleic anhydride resin is in an amount of 5-20 parts by weight in the halogen-free flame retardant resin composition;

14. The halogen-free flame retardant resin composition claimed in claim 1, wherein said flame retardant is anyone selected from the group consisting of resorcinol-bis(diphenyl phosphate), bisphenol A-bis(diphenyl phosphate), resorcinol-bis(2,6-dimethylphenyl phosphate), dimethyl methyl phosphonate and phosphazene compounds, or a mixture of at least two selected therefrom.

15. The halogen-free flame retardant resin composition claimed in claim 1, wherein said flame retardant is in an amount of 3-20 parts by weight in the halogen-free flame retardant resin composition.

16. The halogen-free flame retardant resin composition claimed in claim 1, wherein said acidic filler has a particle size of 50 nm-50 m;

17. The halogen-free flame retardant resin composition claimed in claim 1, wherein said acidic filler has a pH of 4-6.

18. The halogen-free flame retardant resin composition claimed in claim 1, wherein said acidic filler is in an amount of 5-60 parts by weight in the halogen-free flame retardant resin composition.

19. The halogen-free flame retardant resin composition claimed in claim 1, wherein said non-acidic filler is anyone selected from the group consisting of calcium carbonate, calcium sulfate, alumina, barium sulfate, ceramic powder, talc powder and hydrotalcite, or a mixture of at least two selected therefrom.

20. The halogen-free flame retardant resin composition claimed in claim 1, wherein preferably, said non-acidic filler is added in an amount of 0-100 parts by weight;

21. The halogen-free flame retardant resin composition claimed in claim 1, wherein the halogen-free flame retardant resin composition further comprises from 0.1 to 1 part by weight of (F) a curing accelerator.

22. The halogen-free flame retardant resin composition claimed in claim 1, wherein said curing accelerator is anyone selected from the group consisting of imidazole accelerators and their derivatives, pyridine accelerators and Lewis acid accelerators, or a mixture of at least two selected therefrom.

Description

EMBODIMENTS

[0068] The technical solutions of the present invention are further explained by the following embodiments.

[0069] The following refers to the specific embodiments of the present invention. It should be pointed out that, without departing from the principles of the examples of the present invention, a number of amendments and improvements can also be made for those ordinarily skilled in the art. Moreover, such amendments and improvements are also deemed as the protection scopes of the examples of the present invention.

[0070] The examples of the present invention are further stated below. The examples of the present invention are not limited to the following specific examples, and could be properly amended and carried out without changing the scopes of the claims.

[0071] Unless otherwise stated hereinafter, said parts refers to weight parts, and said % refers to weight %.

[0072] The materials and brands involved in the examples and comparison examples are provided as follows. [0073] (A) Epoxy resin [0074] A1: alkylphenol epoxy resin, a product having the product model of KES-7595 and provided by KOLON; [0075] A2: DCPD epoxy, having the model of 7200H and purchased from DIC; [0076] (B) Benzoxazine resin [0077] B1: a product having the model of LZ8290H62 and purchased from Huntsman; [0078] B2: a product having the model of D125 and purchased from EM Technology; [0079] (C) Styrene Maleic Anhydride Resin [0080] C1: a product having the model of EF40 and purchased from Sartomer; [0081] C2: a product having the model of EF60 and purchased from Sartomer; [0082] (D) Flame retardant [0083] D1: a product having the model of PX-200 and purchased from Daihachi Chemical; [0084] D2: a product having the model of SPB-100 and purchased from Otsuka Chemical; [0085] (E) Filler [0086] E1: silica DQ-1030 having a pH=4.0 and purchased from Novoray; [0087] E2: mica powder GD-2 having a pH=5.0 and purchased from Gerui; [0088] E3: carbon black having a pH=3.0 and purchased from Tianjin Xinglongtai Chemical Products Technology Co., Ltd; [0089] E4: boehmite BG-615 having a pH=6.8 and purchased from Bengbu Xinyuan; [0090] E5: Silica MEGASIL525 having a pH=6.5 and purchased from Sibelco; [0091] E6: spherical silica power SC2500-SEJ having a pH pH=8.0 and purchased from Admatechs; and [0092] (F) Curing accelerator [0093] F1: 2-phenylimidazole purchased from Shikoku Chemicals.

[0094] The resin compositions provided in the examples and comparison examples were used to prepare laminates for printed circuit according to the following method, and the performance test was carried out for the prepared laminates.

[0095] The laminates for printed circuit are prepared by [0096] {circle around (1)} binding one or more prepregs together by heating and pressing to prepare a laminate; [0097] {circle around (2)} binding metal foils to one or both sides of the laminate prepared in step 0; [0098] {circle around (3)} laminating in a laminator;
overlapping 8 sheets of prepregs and 2 sheets of metal foils in an amount of one ounce (having a thickness of 35 m) during the step {circle around (2)};
during the step {circle around (3)}, laminating at 80-140 C. which is the material temperature, a temperature rising rate of 1.5-2.5 C./min, applying a full pressure of about 350 psi when the outer material temperature is 80-100 C.; controlling the material temperature at 195 C. and maintaining the temperature for at least 60 min.

[0099] The formulations and performance test results of the resin compositions provided in the examples and comparison examples are stated in Tables 1-3.

TABLE-US-00001 TABLE 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 A1 20 20 50 50 80 80 A2 B1 80 80 50 50 20 20 B2 C1 10 10 15 0 30 30 C2 20 D1 10 10 20 20 30 30 D2 E1 40 50 50 20 10 50 E2 E3 E4 E5 E6 F 0.2 0.2 0.2 0.2 0.2 0.2 Number of 1 1 1 1 1 1 DSC peaks Glass transition 183 191 168 173 158 165 temperature (Tg, C.) Flame V-0 V-0 V-0 V-0 V-0 V-0 retardancy (1.60 mm) Water 0.08 0.07 0.09 0.12 0.14 0.1 absorption(%) Peeling 1.35-1.55 1.45-1.60 1.25-1.45 1.15-1.30 1.10-1.25 1.20-1.40 strength range (N/mm) CTE (%) 2.3 2.2 2.4 2.7 2.8 2.6 Dielectric 4.30 4.35 4.25 4.19 4.05 4.17 constant (1 GHz) Dielectric loss 0.0085 0.0078 0.0065 0.0065 0.0060 0.0055 factor (1 GHZ)

TABLE-US-00002 TABLE 2 Example Example Example 7 Example 8 Example 9 10 11 A1 80 80 60 50 50 A2 B1 20 20 50 50 B2 10 C1 30 30 15 15 C2 5 D1 10 10 20 20 D2 10 E1 2 65 30 E2 50 20 E3 30 E4 E5 20 E6 F 0.2 0.2 0.2 0.2 0.2 Number of DSC peaks 2 1 1 1 1 Glass transition temperature 158 174 162 169 167 (Tg, C.) Flame retardancy (1.60 mm) V-1 V-0 V-0 V-0 V-0 Water absorption (%) 0.23 0.11 0.12 0.09 0.09 Peeling strength range (N/mm) 0.60-0.85 1.05-1.25 1.20-1.35 1.25-1.45 1.25-1.45 CTE (%) 3.0 2.4 2.3 2.4 2.4 Dielectric constant (1 GHz) 3.90 4.25 4.20 4.25 4.25 Dielectric loss factor 0.0100 0.0058 0.0095 0.0065 0.0065 (1 GHZ)

TABLE-US-00003 TABLE 3 Comp. Comp. Comp. Comp. Comp. Comp. Comp. Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 A1 50 50 50 50 50 90 A2 50 B1 50 50 50 50 50 50 B2 10 C1 15 15 15 15 15 C2 5 D1 20 20 20 20 20 20 D2 10 E1 50 50 E2 50 E3 E4 50 E5 50 E6 50 F 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Number of 1 1 2 2 2 2 1 DSC peaks Glass transition 162 175 156 168 156 157 159 temperature (Tg, C.) Flame V-0 V-0 V-0 V-0 V-0 V-0 V-1 retardancy (1.60 mm) Water 0.09 0.08 0.25 0.09 0.09 0.09 0.13 absorption (%) Peeling 1.25-1.45 1.30-1.45 0.95-1.15 0.80-0.90 0.80-0.90 0.80-0.90 0.95-1.05 strength range (N/mm) CTE (%) 2.4 2.3 2.8 2.4 2.4 2.4 2.4 Dielectric 4.25 4.05 3.9 4.25 4.25 4.25 4.2 constant (1 GHz) Dielectric loss 0.0090 0.0070 0.0085 0.0065 0.0065 0.0065 0.0100 factor (1 GHZ)

[0100] The items and specific methods of the performance test are as follows. [0101] (a) Glass transition temperature (Tg): tested according to the DSC method as stipulated under IPC-TM-650 2.4.25 in accordance with Differential Scanning calorimetry; [0102] (b) Flame retardancy: tested according to the UL-94 standard; [0103] (c) water absorption: tested according to the method as stipulated under IPC-TM-650 2.6.2.1; [0104] (d) Number of DSC peaks: instrument manufacturer: TA, US; having a temperature rising rate of 10 C./min under N2 environment; the number of peaks at a temperature between 100 C.250 C. on the DSC curve; [0105] (e) Peeling strength: tested according to the method as stipulated under IPC-TM-650 2.4.8 [0106] (f) Coefficient of thermal expansion: tested according to the method IPC-TM-650 2.4.24; [0107] (g) Dielectric constant and dielectric loss factor: testing dielectric constant and dielectric loss factor under 1 GHz by the method stipulated under IPC-TM-650 2.5.5.5.

[0108] The followings are the physical property analysises.

[0109] (1) By comparing Example 3 with Comparison Example 1, it can be seen that the addition of styrene maleic anhydride resin in Example 3 makes the prepared plates have a higher glass transition temperature, a lower dielectric loss factor and better dielectric properties than no addition of styrene maleic anhydride resin in Comparison Example 1. By comparing Example 3 with Comparison Example 2, it can be seen that the addition of alkylphenol epoxy resin in Example 3 makes the prepared plates have a lower dielectric loss factor and better dielectric properties than no addition of alkylphenol epoxy resin in Comparison Example 2. By comparing Example 3 with Comparison Example 3, it can be seen that the addition of an acidic filler having a pH of 2-6 in Example 3 makes less DSC peak number, and makes the prepared plates have a higher glass transition temperature, a lower water absorption, a higher peeling strength, and a lower dielectric loss factor than no addition of filler in Comparison Example 3.

[0110] According to the examples and comparison examples, it can be seen that the combination of alkylphenol epoxy resin and styrene maleic anhydride resin can achieve better dielectric properties. Moreover, the addition of the acidic filler could make up its defect of weak interlayer binding force, so as to reach synergistic effects of said three materials, effectively increase the dielectric properties and peeling strength stability of the resin composition and make the prepregs and printed circuit laminates have excellent comprehensive performances.

[0111] (2) By comparing Example 3 with Comparison Examples 4-6, it can be seen that the addition of an acidic filler having a pH of 2-6 in Example 3 makes less DSC peak number, and makes the prepared plates have a higher peeling strength than the addition of an acidic filler having a pH of higher than 6 in Comparison Examples 4-5;

the addition of an acidic filler having a pH of 2-6 in Example 3 makes less DSC peak number, and makes the prepared plates have a higher glass transition temperature and a higher peeling strength than the addition of an alkaline filler in Comparison Example 6.

[0112] By comparing Example 3 with Comparison Examples 4-6, it can be seen that the addition of an acidic filler having a pH of 2-6 in Example 3 greatly promotes the polymerization of benzoxazine and epoxy resin, decreases the curing temperature needed for the polymerization of benzoxazine and epoxy resin, and makes complete reaction of benzoxazine and epoxy resin. Meanwhile, it can also make the prepared laminates have a higher anti-stripping stability, a higher glass transition temperature, a low water absorption, a high heat resistance, a high bending strength and a better processability, and achieve a low coefficient of thermal expansion.

[0113] (3) By comparing Example 9 with Comparison Example 7, it can be seen that the lower content of alkylphenol epoxy resin in Example 9 can make the laminates have a higher glass transition temperature, the V-0 flame resistance level, a lower water absorption, a higher peeling strength, a lower coefficient of thermal expansion and a lower dielectric loss factor.

[0114] (4) By comparing Examples 5-6 with Comparison Examples 7-8, it can be seen that the addition of the acidic filler in an amount of 5-60 parts by weight in Examples 5-6 makes less DSC peak number, more excellent catalytic action, a higher glass transition temperature, the V-0 flame resistance level, a lower water absorption, a higher peeling strength and a lower coefficient of thermal expansion than the addition of the acidic filler in an amount of less than 5 parts by weight in Example 7; and the addition in Examples 5-6 makes a higher peeling strength and a better processability than the addition of the acidic filler in an amount of higher than 60 parts by weight in Example 8.

[0115] It could be concluded according to the aforesaid results that, while ensuring a higher glass transition temperature and excellent moisture and heat resistance, the halogen-free flame retardant resin composition of the present invention effectively improves the dielectric properties and the peeling strength stability of the resin composition, and provides the prepregs and copper clad laminates with excellent comprehensive performances.

[0116] It shall be noticed and understood that various amendments and improvements can be made to the present invention detailedly stated above, without departing from the spirit and scope of the present invention as set forth in the appended claims.

[0117] The applicant claims that the present invention describes the detailed process of the present invention, but the present invention is not limited to the detailed process of the present invention. That is to say, it does not means that the present invention shall be carried out with respect to the above-described detailed process of the present invention. Those skilled in the art shall know that any improvements to the present invention, equivalent replacements of the raw materials of the present invention, additions of auxiliary components, selections of any specific ways all fall within the protection scope and disclosure scope of the present invention.