Halogen-free thermosetting resin composition, prepreg, laminate and printed circuit board comprising the same

Abstract

The present invention provides a halogen-free thermosetting resin composition, a prepreg, a laminate and a printed circuit board comprising the same. The halogen-free thermosetting resin composition comprises, based on 100 parts by weight of organic solids, (A) from 30 to 60 parts by weight of a halogen-free thermosetting resin, (B) from 10 to 35 parts by weight of a phenolic curing agent, and (C) a phosphorus-containing flame retardant. The prepregs, laminates and printed circuit boards prepared from the halogen-free thermosetting resin composition of the present invention have excellent dimensional stability and dielectric properties, high adhesive force, high heat resistance, low water absorption and better processability, and can achieve halogen-free flame retardancy and reach UL94 V-0.

Claims

1. A halogen-free thermosetting resin composition, based on 100 parts by weight of organic solids, comprising the following components: (A) from 30 to 60 parts by weight of a halogen-free epoxy resin; (B) from 10 to 35 parts by weight of a phenolic curing agent; and (C) a phosphorus-containing flame retardant, wherein the halogen-free epoxy resin comprises the epoxy resin having the structure of Formula (a): ##STR00007## wherein T.sub.1 and T.sub.2 are each independently selected from the group consisting of a hydrogen atom or a structure according to Formula (I), wherein n1 and n3 represent the numbers of repeating units and are each independently an integer greater than or equal to 1, wherein n2 represents the number of a repeating unit and is an integer greater than or equal to 0, ##STR00008## wherein n4 represents the number of a repeating unit, and is an integer greater than or equal to 1, wherein the epoxy resin having the structure of Formula (a) has a molecular weight of 1000-20000, and wherein the epoxy resin having the structure of Formula (a) is in an amount of 50 wt. % or more of the halogen-free epoxy resin.

2. The halogen-free thermosetting resin composition of claim 1, wherein besides the epoxy resin having the structure of Formula (a), the component (A) halogen-free epoxy resin further comprises other halogen-free epoxy resins selected from the group consisting of bisphenol A epoxy resin, bisphenol F epoxy resin, phenol novolac epoxy resin, bisphenol A novolac epoxy resin, o-cresol novolac epoxy resin, dicyclopentadiene epoxy resin, isocyanate epoxy resin, phosphorus-containing epoxy resin, Xylok-type epoxy resin, biphenyl epoxy resin, or a mixture of at least two selected therefrom.

3. The halogen-free thermosetting resin composition of claim 1, wherein the phenolic curing agent of component (B) is one or more phenolic resins selected from the group consisting of phenolic resins having the following structure, or a mixture of at least two selected therefrom: ##STR00009## wherein X.sub.1 is ##STR00010## where one of the floating bonds is a hydroxyl group attached to X.sub.1 as shown above, wherein X.sub.2 and X.sub.3 are each ##STR00011## where one of the floating bonds is a hydroxyl group attached to X.sub.2 and X.sub.3 as shown above, wherein R.sub.1 is selected from the group consisting of a hydrogen atom, a substituted C.sub.1-C.sub.5 linear alkyl, an unsubstituted C.sub.1-C.sub.5 linear alkyl, a substituted C.sub.1-C.sub.5 branched alkyl, or an unsubstituted C.sub.1-C.sub.5 branched alkyl, wherein Y.sub.1 and Y.sub.2 are each independently selected from the group consisting of a single bond a CH.sub.2 ##STR00012## wherein R.sub.2 is selected from the group consisting of a hydrogen atom, a substituted C.sub.1-C.sub.5 linear alkyl, an unsubstituted C.sub.1-C.sub.5 linear alkyl, a substituted C.sub.1-C.sub.5 branched alkyl, or an unsubstituted C.sub.1-C.sub.5 branched alkyl, and wherein m is an integer selected from 1-10.

4. The halogen-free thermosetting resin composition of claim 1, wherein based on 100 parts by weight of organic solids the component (C) phosphorus-containing flame retardant is added in an amount of from 5 to 30 parts by weight.

5. The halogen-free thermosetting resin composition of claim 1, wherein based on 100 parts by weight of organic solids the halogen-free thermosetting resin composition further comprises from 0 to 5 parts by weight of an amine curing agent.

6. The halogen-free thermosetting resin composition of claim 1, wherein based on 100 parts by weight of organic solids the halogen-free thermosetting resin composition further comprises from 0 to 200 parts by weight of a filler, not including 0.

7. The halogen-free thermosetting resin composition of claim 1, wherein the halogen-free thermosetting resin composition further comprises a curing accelerator.

8. The halogen-free thermosetting resin composition of claim 2, wherein the other halogen-free epoxy resin is a phosphorus-containing epoxy resin.

9. The halogen-free thermosetting resin composition of claim 1, wherein component (C) phosphorus-containing flame retardant is selected from the group consisting of tri(2,6-dimethylphenyl)phosphine, 10-(2,5-dihydroxylphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 2,6-di(2,6-dimethylphenyl)phosphinophenyl, 10-phenyl-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, phenoxyphosphazene compound, phosphate, polyphosphate, phosphonate, polyphosphonate, or a mixture of at least two selected therefrom.

10. The halogen-free thermosetting resin composition of claim 5, wherein the amine curing agent is selected from the group consisting of dicyandiamide, diaminodiphenylsulfone, diaminodiphenyl ether, and diaminodi-phenylmethane, or a mixture of at least two selected therefrom.

11. The halogen-free thermosetting resin composition claimed of claim 6, wherein the filler is selected from the group consisting of organic fillers and inorganic fillers.

12. The halogen-free thermosetting resin composition of claim 6, wherein the filler is surface-treated inorganic fillers, wherein the surface-treating agent for surface treatment is selected from the group consisting of a silane coupling agent, an organic silicone oligomer, a titanate coupling agent, or a mixture of at least two selected therefrom, and wherein the surface-treating agent is used in an amount of 0.1-5.0 mass %, based on 100 mass % of the inorganic filler.

13. The halogen-free thermosetting resin composition of claim 11, wherein the inorganic filler is selected from the group consisting of non-metallic oxides, metal nitrides, non-metallic nitrides, inorganic hydrates, inorganic salts, metal hydrates, inorganic phosphorus, or a mixture of at least two selected therefrom, and wherein the organic filler is selected from the group consisting of a polytetrafluoroethylene powder, a polyphenylene sulfide, a polyethersulfone powder, or a mixture of at least two selected therefrom.

14. The halogen-free thermosetting resin composition of claim 6, wherein the filler is silica and the filler has a median particle size of 1-15 m, and wherein the filler in the halogen-free thermosetting resin composition is added in an amount of 0-100 parts by weight, not including 0, based on 100 parts by weight of organic solids.

15. The halogen-free thermosetting resin composition of claim 7, wherein the curing accelerator is added in an amount of 0.01-0.5 parts by weight based on 100 parts by weight of the total amounts of components (A), (B) and (C).

16. The halogen-free thermosetting resin composition of claim 7, wherein the curing accelerator is selected from the group consisting of imidazole compounds, derivatives of imidazole compounds, piperidine compounds, Lewis acid, triphenyl phosphine, or a mixture of at least two selected therefrom.

17. The halogen-free thermosetting resin composition of claim 16, wherein the imidazole compounds are selected from the group consisting of 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecyl-imidazole, or a mixture of at least two selected therefrom, and wherein the piperidine compounds are selected from the group consisting of 2,3-diaminopiperidine, 2,5-diaminopiperidine, 2,6-diaminopiperidine, 2-amino-3-methylpiperidine, 2-amino-4-methylpiperidine, 2-amino-3-nitropiperidine, 2-amino-5-nitropiperidine, 2-amino-4,4-dimethylpiperidine, or a mixture of at least two selected therefrom.

18. A prepreg comprising a reinforcing material and the halogen-free thermosetting resin composition of claim 1 attached thereon after impregnation and drying.

19. A laminate comprising at least one of the prepreg claimed of claim 18.

20. A printed circuit board comprising at least one of the prepreg claimed of claim 18.

Description

EMBODIMENTS

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

(2) The glass transition temperature, dimensional stability, dielectric constant, dielectric loss factor, peeling strength, heat resistance, water absorption, and flame retardancy were measured for the printed circuit laminate (1 prepreg), and the following examples are used for describing in detail.

(3) Please refer to Preparation Example 1, Examples 1-7 and Comparison Examples 1-6.

Preparation Example 1 Preparation of Novel Halogen-Free Epoxy Resin Having the Structure of Formula (a)

(4) Feeding 100 parts of a linear novolac epoxy resin having an epoxy equivalent of about 177 g/eq into a four-necked flask (500 mL) equipped with a polytetrafluoroethylene stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube, heating to 180 C. to 195 C., adding 15-20 parts of diphenylmethane diisocyanate (MDI) having an isocyanate equivalent of 125 g/eq at about 190 C., feeding 2 parts of 2-ethyl-4-methylimidazole (an accelerator) and reacting at 180-195 C. for 12 h, continuously sampling until it was confirmed by FT-IR that the isocyanate peak disappeared completely, stopping stirring and heating, removing solvent to obtain a novel halogen-free epoxy resin having an epoxy equivalent of 230-260 g/eq and a softening point of 70-80 C.

(5) The examples of the present invention are described in detail below, but the present invention is not limited by the examples. Unless otherwise specified, the term parts represents parts by weight, and % represents wt. %.

(6) (A) halogen-free epoxy resin;

(7) (A-1) novel halogen-free epoxy resin (the preparation process being described above, the structure thereof being the structure of Formula (a), having an epoxy equivalent of 246 g/eq);

(8) (A-2) linear phenolic epoxy resin KEP-1138 (trade name from KOLON, Korea);

(9) (A-3) dicyclopentadiene-type epoxy resin HP-7200H (trade name from Dainippon Ink);

(10) (A-4) isocyanate-modified epoxy resin XZ-97103 (trade name from DOW, USA);

(11) (B) phenolic resin;

(12) (B-1) dicyclopentadiene-type phenolic resin PD9110 (trade name from Taiwan Changchun);

(13) (B-2) biphenyl-type phenolic resin MEH-7851H (trade name from Meiwa Plastic Industries, Ltd, Japan);

(14) (B-3) linear phenolic resin;

(15) (C) amine curing agent;

(16) (C-1) dicyandiamide DICY (trade name from Ningxia Daiei);

(17) (C-2) diaminodiphenyl sulfone (trade name from Taiwan Yin Health);

(18) (D) phosphorus-containing flame retardant

(19) XZ92741 (trade name from DOW, USA);

(20) (E) 2-phenylimidazole (trade name from Shikoku Chemicals Corporation, Japan);

(21) (F) filler

(22) spherical silica powder (having an average particle diameter of 1 to 10 m and a purity of 99% or more).

(23) TABLE-US-00001 TABLE 1 Formulations of each example and Comparison example and physical properties thereof Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 A-1 40 30 30 48 60 48 40 A-2 5 30 A-3 A-4 B-1 30 35 10 26 15 30 B-2 26 B-3 C-1 3 1 1 1 C-2 4 D 30 30 22 25 20 25 30 E q.s q.s q.s q.s q.s q.s F 40 40 60 80 40 40 Glass transition 160 164 178 165 175 160 161 temperature (DSC) C. Dimensional Radial 747 774 725 690 783 804 834 change Zonal 580 592 550 468 602 595 625 rate (ppm) Dielectric constant 3.57 3.58 3.61 3.63 3.59 3.52 3.43 (1 GHz) Dielectric loss 0.0082 0.0085 0.0078 0.0075 0.0077 0.0079 0.0091 (1 GHz) Peeling strength 1.20 1.21 1.24 1.20 1.24 1.25 1.32 (N/mm) Water absorption 0.07 0.07 0.07 0.07 0.08 0.08 0.09 (%) Dip soldering >120 >120 >120 >120 >120 >120 >120 resistance, 288 C., s Flammability V-0 V-0 V-0 V-0 V-0 V-0 V-0

(24) TABLE-US-00002 TABLE 2 Formulations of each example and Comparison example and physical properties there of Comparison Comparison Comparison Comparison Comparison Comparison Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 A-1 48 20 70 A-2 48 28 A-3 48 A-4 48 B-1 26 26 26 26 15 B-2 B-3 26 C-1 1 1 1 1 1 2 C-2 D 25 25 25 25 25 13 E q.s q.s q.s q.s q.s F 40 40 40 40 40 Glass transition 168 161 166 173 176 169 temperature (DSC) C. Dimensional Radial 1048 884 1021 855 977 995 change Zonal 817 679 789 613 764 758 rate (ppm) Dielectric constant 3.91 3.58 3.87 3.92 3.83 3.85 (1 GHz) Dielectric loss 0.0104 0.0080 0.0099 0.0112 0.0107 0.099 (1 GHz) Peeling strength 1.07 0.99 1.17 1.20 1.21 1.23 (N/mm) Water absorption 0.09 0.07 0.10 0.08 0.08 0.10 (%) Dip soldering >120 >120 >120 >120 >120 >120 resistance, 288 C., s Flammability V-0 V-1 V-0 V-0 V-0 V-1

(25) The test methods of the above characteristics are stated as follows.

(26) (a) glass transition temperature (Tg)

(27) measured according to differential scanning calorimetry (DSC) by the DSC method specified in IPC-TM-650 2.4.25.

(28) (b) dimensional stability

(29) measured according to the method under IPC-TM-650 2.4.39, respectively measuring the dimension of Sample A and the dimension after treatment, calculating the dimensional change rate of radial and zonal directions; the sample being treated under the conditions of 2 h/150 C.

(30) (c) dielectric constant and dielectric loss factor

(31) measuring the dielectric constant and dielectric loss factor at 1 GHz by the resonance method using strip lines according to IPC-TM-650 2.5.5.5.

(32) (d) peeling strength

(33) testing the peeling strength of the metal cap layer under the test conditions of after thermal stress according to the method under IPC-TM-650 2.4.8.

(34) (e) water absorption

(35) measured according to the method under IPC-TM-650 2.6.2.1.

(36) (f) dip soldering resistance

(37) observing the stratifying and bubbling time according to IPC-TM-650 2.4.13.1.

(38) (g) Flammability

(39) measured according to the UL 94 vertical combustion method.

(40) From the physical property data in Tables 1 and 2, it could be found that the dielectric constant and dielectric loss are higher, and the peeling strength is lower when a specific phenolic curing agent and an amine curing agent are used to co-cure a linear phenolic epoxy in Comparison Example 1. Comparison Example 2 discloses a specific phenolic curing agent and an amine curing agent are used to co-cure dicyclopentadiene-type phenolic epoxy. The resultant copper-clad laminate has a poor dimensional stability, a lower peeling strength, and a flame retardancy of only UL V-1 Level. Comparison Example 3 discloses a specific phenolic curing agent and an amine curing agent are used to co-cure isocyanate-modified epoxy. The resultant copper-clad laminate has worse dielectric properties and dimensional stability. Comparison Example 4 discloses a common linear phenolic curing agent and an amine curing agent are used to co-cure a halogen-free epoxy resin. The resultant copper-clad laminate has worse dielectric properties, so that it could not meet the demands on thinness and shortness of consumer electronics. Comparison Example 5 discloses a dicyclopentadiene-type phenolic curing agent and an amine curing agent are used to co-cure an epoxy resin, wherein the novel halogen-free epoxy resin is in a ratio of less than 50% of the epoxy resin. The resultant copper-clad laminate has a worse dimensional stability and dielectric properties. Comparison Example 6 discloses a dicyclopentadiene-type phenolic curing agent and an amine curing agent are used to co-cure a large amount of the novel halogen-free epoxy resin in a ratio of higher than 70 parts by weight. The resultant copper-clad laminate has a general dimensional stability and dielectric properties, a higher water absorption, and insufficient flame retardancy, and could not reach the V-0 level.

(41) In Examples 1-7, a specific phenolic curing agent is used alone or in combination with an amine curing agent to cure the epoxy resin. The resultant copper-clad laminate has higher glass transition temperature, excellent dimensional stability and dielectric properties, high peeling strength and high heat resistance, and can achieve halogen-free flame retardancy and reach UL94 V-0.

(42) As stated above, the laminates for printed circuits of the present invention have more excellent dimensional stability and dielectric properties, high adhesive force, high heat resistance, low water absorption and better processability, and are suitable for high density interconnected fields. In addition, the laminates of the present invention can achieve the V-0 standard in the flammability test UL94 with a halogen content within the scope of JPCA halogen-free standard requirements and have environmental protection effect.

(43) The applicant declares that the present invention discloses the detailed process via the aforesaid examples. However, the present invention is not limited by the aforesaid detailed process. That is to say, it does not mean that the present invention cannot be carried out unless the aforesaid detailed process is used. Those skilled in the art shall know that any improvement, equivalent replacement of various raw materials of the present invention, addition of auxiliary ingredients, selection of specific modes and the like all fall within the protection scope and disclosure of the present invention.