Patent Application
20130273796
The present invention relates to a resin composition, in particular to a halogen-free high-Tg (glass transition temperature) resin composition, prepreg and laminated fabricated by using the same.
Polytriazine prepared from bi- or multi-functional aromatic cyanates has a high Tg, excellent dielectric properties and coefficient of thermal expansion, and is generally applied in HDI multi-layer PCB and packaging substrates. The popular BT copper-clad plate on the market is prepared from bismaleimide-triazine resin, generally and primarily bromine-containing flame retardant. With the acceleration development of environmental protection consciousness, phosphor-based flame retardants will replace the conventional bromine-based flame retardants. However, phosphor-based flame retardants are easy to absorbing water to results in measling of the sheet materials.
In addition, although only heating is required to solidify the raw materials above, a catalytically effective amount of transition metal compounds are generally needed, e.g. cobalt acetyl acetate, copper acetyl acetate or zinc octoate. Since these compounds are toxic and/or environmentally hazardous (especially eliminating the material fabricated by using the same) and may have an effect on the electromagnetic property, they are not the desirable raw materials.
In order to solve said problem, benzoxazine resin is introduced. Although JP2004182851 has disclosed blending cyanate, benzoxazine, epoxy resin to obtain a formulation composition, benzoxazine resin is easy to opening the loop when heated, to produce a large amount of hydroxyl groups, to cause the reaction of the by-products and to affect the cyclization of cyanates and finally affect the performances of the sheet materials. Thus the present invention uses as the resin benzoxazine resin having a greater steric hindrance and a slower reactivity, wherein hydroxyl groups produced by solidification may accelerate the cyclization of cyanates, so as to greatly reduce the consumption of the transition metals. In addition, benzoxazine has a certain flame retardant resistance, and can also achieve flame retarding resistance when used in combination with a suitable amount of phosphor-containing flame retardant, without any problems, such as the sheet materials and phosphor-containing flame retardant being easy to moisture absorption, measling and sharp reduction of physical properties, e.g. flexural modulus. Meanwhile, benzoxazine per se has a low water absorption, an excellent heat resistance and a better electric property.
The object of the present invention lies in providing a halogen-free high-Tg resin composition, into which a certain amount of benzoxazine resin is added and used together with styrene-maleic anhydride oligomers as a curing agent of the resin, so as to improve the water absorption, heat resistance and electrical property of the resin composition.
Another object of the present invention lies in providing a prepreg fabricated by using the halogen-free high-Tg resin composition, having a low dielectric constant, a low dielectric loss constant, a high glass transition temperature, a low water absorption and a high heat resistance.
Another object of the present invention lies in providing a laminate fabricated by using the halogen-free high-Tg resin composition, having a low dielectric constant, a low dielectric loss constant, a high glass transition temperature, a low water absorption and a high heat resistance.
In order to achieve the objects above, the present invention provides a halogen-free high-Tg resin composition, comprising, based on parts by weight of organic solids,
wherein R1 in formula (I) represents H, alkane, alkene or alkyne; X is selected from the group consisting of —CH2—, —CH(CH3)—, —C(CH3)2—, —C(CF3)2—, —O—, —S—, —C(═O)—, —C(O)—, —OC(═O)O—,
wherein n in formula (II) is any integer from 0-10, and R2 is H or methyl;
wherein n in formula (III) is any integer from 0-10.
The compound having a dihydrobenzoxazine ring is selected from the group consisting of the prepolymers formed from the compounds of formulae (IV), (V) and (VI) and one or more compounds above,
wherein R1 in formula (IV) represents H, alkane, alkene or 1 alkyne; X is selected from the group consisting of —CH2—, —CH(CH3)—, —C(CH3)2—, —C(CF3)2—, —O—, —S—, —C(═O)—, —OC(═O)—, —OC(═O)O—,
wherein R3 represents methyl or phenyl group;
wherein n in formula (V) is any integer from 0-10; R2 is H or methyl; R3 represents methyl or phenyl group;
wherein n in formula (VI) is any integer from 0-10; R3 represents methyl or phenyl group.
The bismaleimide resin is selected from the group consisting of the prepolymers formed from the compounds of formula (VII) and one or more compounds above,
Wherein R1 represents H, alkane, alkene or alkyne,
The polyepoxy compound comprises at least one compound selected from the group consisting of
The phosphorus-containing flame retardant is at least one compound selected from the group consisting of phosphate and compounds thereof, phenoxylphosphonitrile compounds, phosphaphenanthrenes and derivatives thereof.
The phosphor content in the halogen-free high-Tg resin composition is controlled within 1-5 wt. %; the nitrogen content thereof is controlled within 1-5 wt. %.
The halogen content in the halogen-free high-Tg resin composition is controlled below 0.09 wt. %.
The present invention further provides a prepreg fabricated by using the halogen-free high-Tg resin composition, comprising a base material and the halogen-free high-Tg resin composition adhered to the base material after impregnation drying, wherein the base material is a nonwoven fabric or other fabrics.
The present invention further provides a laminate fabricated by using the halogen-free high-Tg resin composition, comprising several laminated prepregs, each of which comprises a base material and the halogen-free high-Tg resin composition adhered to the base material after impregnation drying.
The present invention has the following beneficial effects. (1) The halogen-free high-Tg resin composition of the present invention involves resin reacting cyante resin with benzoxazine and epoxy resin to form a triazine structure and has a low CTE, a high Tg and an excellent dielectric property. (2) The halogen-free high-Tg resin composition of the present invention uses as the resin benzoxazine resin having a greater steric hindrance and a slower reactivity, wherein hydroxyl groups produced by solidification may accelerate the cyclization of cyanates, so as to greatly reduce the consumption of the transition metals. In addition, benzoxazine has a certain flame retardant resistance, and can also achieve flame retarding resistance when used in combination with a suitable amount of phosphor-containing flame retardant, without any problems, such as the sheet materials and phosphor-containing flame retardant being easy to moisture absorption, measling and sharp reduction of physical properties, e.g. flexural modulus. Meanwhile, benzoxazine per se has a low water absorption, an excellent heat resistance and a better electric property. (3) the addition of epoxy resin into the halogen-free high-Tg resin composition of the present invention may greatly improve the processability. Meanwhile, imidazole is used as the curing accelerator to control the reaction speed of said resin composition by the amount change. (4) The prepreg and laminate fabricated from the halogen-free high-Tg resin composition of the present invention have a low dielectric constant, a low dielectric loss constant, a high heat resistance and a low water absorption, so as to overcome the defects of the current halogen-free high-Tg copper-clad plate, such as low heat resistance, worse humidity resistance, worse processability, difficult to adapt to the welding process of the current lead-free solder, and thus being applicable to a multi-layer circuit board.
The present invention provides a halogen-free high-Tg resin composition, comprising, based on parts by weight of organic solids,
The ingredients are detailedly explained as follows.
The ingredient (A) in the present invention is the cyanate and prepolymer of cyanate, which may further improve the thermal and electrical characteristics of the polymers and articles. The cyanate and prepolymer of cyanate is selected from the group consisting of the prepolymers formed from the compounds of formulae (I), (II) and (II) and one or more compounds above,
wherein R1 in formula (I) represents H, alkane, alkene or alkyne; X is selected from the group consisting of —CH2—, —CH(CH3)—, —C(CH3)2—, —C(CF3)2—, —S—, —C(═O)—, —OC(═O)—, —OC(═O)O—,
wherein n in formula (II) is any integer from 0-10, and R2 is H or methyl; and
wherein n in formula (II) is any integer from 0-10,
The ingredient (A) may be the mixture of these compounds, prepolymers of these compounds, prepolymers of the mixture of these compounds, and the mixture of the prepolymers of these compounds. A prepolymer may be understood an oligomer obtained by partial tripolymerization. These oligomers comprise not only triazinyl groups, but also unreacted cyanate ester groups. Cyanate ester is a known compound, and most of them are commercially available. These prepolymers are also known, and partially and commercially available or readily prepared from cyanate ester. Cyanate ester is used in an amount of 10-50 parts by weight. Too little cyanate ester cannot satisfy the required performances, such as high Tg, low CTE, low dielectric constant Dk and the like; too much cyanate ester may affect other performances of the sheet materials, such as reduced heat resistance, water absorption and the like. The optimum amount thereof is between 10-30 parts by weight.
The ingredient (B) in the present invention, i.e. the compound having a dihydrobenzoxazine ring, is advantageous to increasing the flame retardant property, hygroscopicity, heat resistance, mechanical performance and electrical property of the cured resin and sheet materials fabricated by using the same. The selected benzoxazine resin, i.e. the compound having a dihydrobenzoxazine ring, is selected from the group consisting of the prepolymers formed from the compounds of formulae (IV), (V) and (VI) and one or more compounds above,
wherein R1 in formula (IV) represents H, alkane, alkene or alkyne; X is selected from the group consisting of —CH2—, —CH(CH3)—, —C(CH3)2—, —C(CF3)2—, —O—, —S—, —C(═O)—, —OC(═O)—, —OC(═O)O—,
wherein R3 represents methyl or phenyl group;
wherein n in formula (V) is any integer from 0-10; R2 is H or methyl; R3 represents methyl or phenyl group;
wherein n in formula (VI) is any integer from 0-10; R3 represents methyl or phenyl group.
The benzoxazine resin with side chain, alkane, olefinic bond, alkyne, arene is characterized by a greater steric hindrance and a slow reactivity. Thus said three resins are preferably used in the present invention. The benzoxazine resin may be used alone or in combination in an amount of preferably from 10-50 parts by weight, most preferably from 10 to 40 parts by weight.
The ingredient (C) in the present invention, i.e. the bismaleimide resin, has a high heat resistance, a dimensional stability and excellent electrical property required for encapsulating sheet materials. The bismaleimide resin is selected from the group consisting of the prepolymers formed from the compounds of formula (VII) and one or more compounds above,
Wherein R1 represents H, alkane, alkene or alkyne. The bismaleimide resin may be used alone or in combination in an amount of preferably from 10-50 parts by weight, most preferably from 20 to 45 parts by weight.
The ingredient (D) in the present invention, i.e. the polyepoxy compound, enables the cured resin and the base plate fabricated by using the same to achieve the required basic mechanical and thermal performances. Diglycidyl ether epoxy resin is the better choice. The polyepoxy compound comprises (1) bifunctional epoxy resin, comprising biphenol A-type epoxy resin, biphenol F-type epoxy resin and the like; (2) novolac epoxy resin, comprising phenol-type novolac epoxy resin, orthocresol novolac epoxy resin, biphenol A-type novolac epoxy resin, dicyclopentadiene phenol-type epoxy resin; (3) phosphorus-containing epoxy resin, comprising 9,10-dihydro-9-ova-O-phosphaphenanthrene-10-oxide modified epoxy resin, 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-ova-10-phosphaphenanthrene-10-oxide modified epoxy resin, 10-(2,9-dihydroxynaphthyl)-9,10-dihydro-9-ova-10-phosphaphenanthrene-10-oxide. Said epoxy resins may be used alone or in combination according to the use thereof. For example, the condensate has a better toughness when biphenol F-type epoxy resin is used; the condensate has a higher glass transition temperature when phenol-type novolac epoxy resin or orthocresol novolac epoxy resin is used; the phosphor ingredient required for flame retardanting is provided by using phosphorus-containing epoxy resin. The epoxy resin is used in an amount of preferably from 10-50 parts by weight, most preferably from 20 to 45 parts by weight.
The ingredient (E) of the present invention, i.e. the phosphorus-containing flame retardant, is used to increase the combustion performance of the cured resin and the base plate fabricated by using the same. The phosphorus-containing flame retardant used therein is at least one compound selected from the group consisting of phosphate and compounds thereof, phenoxylphosphonitrile compounds, phosphaphenanthrenes and derivatives thereof. The phosphorus-containing flame retardant not reducing the dielectric constant is the better one, and the preferred phosphorus-containing flame retardant comprises phenoxylphosphonitrile compounds, phosphate compounds and the like. The phosphorus-containing flame retardant may be used alone or in combination according to the synergistic flame retarding effect. The phosphorus-containing flame retardant is used in the present invention in an amount of 5-30 parts by weight. If the amount thereof is less than 5 parts by weight, the flame retarding effect cannot be achieved; if the amount thereof is higher than 30 parts by weight, other performances of the sheet materials will be affected, such as reduced processability, water absorption, bending strength and the like. The phosphor content in the halogen-free high-Tg resin composition is controlled within 1-5 wt. %; the nitrogen content thereof is controlled within 1-5 wt. %.
The halogen-free high-Tg resin composition of the invention further comprises a catalyst and a curing accelerator. The catalyst includes the compounds selected from the group consisting of metal carboxylates, phenols, alcohols, urea derivatives, imidazoles, metal chelates and mixtures thereof, preferably metal carboxylates, e.g. acetyl acetone acid metal salts, or imidazol, wherein the elemental metal is selected from the group consisting of zinc, cobalt, copper, manganese, iron, nickel, aluminium and mixtures thereof. The curing accelerator may be any known accelerator capable of speeding up the solidification of thermosetting resins. The suitable accelerator is selected form the group consisting of various imidazols, tertiary amines, quaternary amines and the like, e.g. 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-hendecylimidazole, benzyl dimethylamine, 2,4,6-tri(dimethylinmethyl)-phenol (DMP-30) and the like.
In the present invention, the well known additives, such as thermoplastic resins, inorganic bulking agents, coloring pigments, antifoaming agents, surface conditioning agents, flame retardants, UV absorbents, antioxidants, flowing adjustment agents and the like, may be added as required. Inorganic bulking agents are primarily used to adjust some physical property effect of the composition, e.g. reducing CTE, increasing thermal conductivity and the like. The fillers may be silica (including crystalline-, to melting-, and spheroidal silica), kaolin, boron nitride, aluminium nitride, alumina, glass fibers, silicon carbide, polytetrafluoroethylene and the like, and one or more of said fillers may be suitably chosen as required. The optimal filler is silica; the moderate value of the particle size of the fillers ranges from 1-15 μm, preferably from 1-10 μm, wherein the fillers having a particle size falling within such range have a better dispersibility. The amount of the fillers is preferably 10-200% of the total weight of the organic solids in the halogen-free high-Tg resin composition.
The prepreg fabricated by using the halogen-free high-Tg resin composition in the invention comprises a base material and the halogen-free high-Tg resin composition adhered to the base material after impregnation drying, wherein the base material is a nonwoven fabric or other fabrics, e.g. natural fibers, organic synthetic fibers and inorganic fibers. The halogen-free high-Tg resin composition of the invention is conventionally prepared by firstly adding solids, then adding a liquid solvent, stirring to complete dissolution, then adding a liquid resin and an accelerator, continuing to stir to a well balance, finally and suitably adjusting with PM (propylene glycol methyl ether) solvent the solid content of the solution to 60-70% to form a liquid cement, impregnating fabrics or organic fabrics such as glass cloth with such liquid cement, heating and drying the impregnated glass cloth in an oven having a temperature of 160° C. for 3-6 minutes, to prepare a prepreg.
The laminate fabricated by using the halogen-free high-Tg resin composition in the present invention comprises several laminated prepregs, each of which comprises a base material and the halogen-free high-Tg resin composition adhered to the base material after impregnation drying. During the preparation of the laminate, two or more pieces of prepregs are adhered together by heating or compression, wherein said laminate may be adhered to metal foils at either or both sides, so as to fabricate metal foil clad laminate. In the examples of the present invention, 8 pieces of prepregs and 2 pieces of one ounce of metal foils are laminated together, laminated by hot press to compress a double-side metal foil clad laminate. Said laminate should necessarily satisfy the following requirements: (1) the temperature increasing rate of the lamination should be generally controlled at 1.5-2.5° C./min when the material temperature ranges from 80-140° C.; (2) the pressure setup of the lamination: a full pressure of about 350 psi is applied when the outside material temperature ranges from 80-100° C.; (3) the material temperature is controlled at 195° C. during the curing for 90 minutes. Said metal foils are copper foils, nickel foils, aluminium foils and SUS foils and the like, and the materials are not limited.
The dielectric constant, dielectric loss constant, heat resistance, water absorption, glass transition temperature, flame retarding resistance of the laminate fabricated above are measured, and further detailed stated and described in the following examples.
The examples of the present invention are detailedly stated as follows, but the present invention is not limited within the scope of the examples. Unless otherwise specified, the part represents the weight part, and the % represents “wt. %”.
Spherical silicon micropowder (having an average particle size of 1-10 μm and a purity of more than 99%)
The above characteristics are measured by the following methods,
In accordance with the differential scanning calorimetry, the DSC method stipulated under IPC-TM-650 2.4.25 is conducted for measurement.
According to the test conditions of “after thermal stress” in the method in accordance with IPC-TM-650 2.4.8, the peeling strength of the metal cover coat is tested.
In accordance with UL94
The samples (the basis material having a size of 100×100 mm) which remained in pressure cooking device (121° C., 105 Kpa) for 2 hours were impregnated in a solder bath heated to 260° C. for 20 seconds, to observe with eyes (h1) presence of delamination, (h2) presence of white plaque or wrinkling, O in the table represents no change; Δ represents white plaque; x represents delamination.
In accordance with IPC-TM-650 2.6.2.1
According to the resonance method of using strip lines, dielectric loss and dielectric loss factor at 1 GHz are measured in accordance with IPC-TM-650 2.5, 5.5
In accordance with IPC-TM-650 2.4.24, the Z-axle CTE of the printing plate and insulated base materials was measured.
In accordance with JPCA-ES-01-2003 halogen-free copper clad plate test method, halogen content of the copper clad foil laminate was measured by the oxygen flask combustion and ion chromatography.
According to the results above, it can be seen that the present invention can achieve the efficacy of a low dielectric constant, a low dielectric loss factor, a high glass transition temperature, a burning resistance, a Soldering resistance and a water absorption. Meanwhile, the processability, halogen content of the sheet materials fall within the halogen-free requirement scope under JPCA and can achieve the V-0 standard in fire resistance test UL94. The halogen-free high-Tg resin composition of the present invention sufficiently utilizes the synergistic properties of cyanate resins, benzoxazine resin, bismaleimide resins and epoxy resins, wherein the halogen content is less than 0.09%, so as to achieve the environmental protection efficacy. The printed circuit board fabricated from the halogen-free high-Tg resin composition of the present invention not only has the equivalent mechanical performance and heat resistance to the general FR-4 printed circuit board, but also has an excellent high-Tg dielectric performance and can meet the requirements of high Tg transmission system on the printed circuit board.
The aforesaid examples are only the optimal examples of the present invention. As for those ordinarily skilled in the art, various other corresponding changes and deformations can be made on the basis of the technical solutions and technical concepts of the present invention, wherein all these changes and deformations should fall within the protection scope of the claims of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201010602885.4 | Dec 2010 | CN | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/CN2011/079306 | 9/3/2011 | WO | 00 | 6/24/2013 |
