TWI382055B - Thermosetting resin composition - Google Patents

Description

Thermosetting resin composition

The present invention relates to a thermosetting resin composition, and more particularly to a halogen-free flame retardant thermosetting resin composition.

As is known to those skilled in the art, the basic materials of flexible printed circuit boards include copper foil substrates, cover films (i.e., protective films), and other components. The copper foil substrate generally comprises a copper foil, a substrate, and an adhesive as a medium, and the cover film comprises two parts of an adhesive and a substrate. Herein, since the flexible printed circuit board is used more than in a high temperature environment, the adhesive for the copper foil substrate or the cover film needs to have a certain degree of fire retardantability and reliability.

An epoxy/butadiene rubber (Epoxy/NBR) system is typically employed in this application. Since the ignition point of the epoxy resin is not enough to load the high temperature of the circuit environment, in addition to the resin/rubber component, the flame retardant is added to the material to meet the V-0 requirement of the UL-94 fire test. Halogen-containing compounds such as tetrabromobisphenol A (TBBA) are common flame retardants for improving the flame retardancy of epoxy resins. However, such halogenated flame retardants such as tetrabromide diol can produce toxic substances such as dioxin or benzofuran when they are burnt at improper temperatures, which endanger human health and cause environmental pollution.

In addition, although the above epoxy resin/butadiene rubber system can meet the requirements of flame retardant properties, since the interface is a glossy copper surface, there is still a lack of subsequent properties, which cannot meet the requirements of tear resistance and weather resistance. Herein, a dicyandiamide hardener is generally added to promote adhesion to a glossy copper surface. The use of the dicyandiamide hardener improves the adhesion between the adhesive and the glossy copper surface, but the resulting material is highly hygroscopic because of its incomplete reactivity. In addition to the problem of exploding in the process of mounting, the high hygroscopicity is also prone to metal migration between the lines.

Due to the introduction of the Restriction of Hazardous Substances (RoHS), halogen-containing materials are gradually replaced by halogen-free materials, and in order to meet the requirements of flame retardancy, the addition of flame retardants in large amounts detracts from other material properties (such as adhesion). On the other hand, lead-free processes have been introduced into the component mounting of flexible printed circuit boards. Therefore, the higher the requirements for heat resistance, weather resistance, adhesion and harm to the human body and the environment, the material selection, ratio and process of the suitable adhesive are not easy to achieve.

As can be seen from the above description, the adhesives used in today's flexible printed circuit board materials often cause problems such as affecting human health and environmental burden due to the use of materials, and cannot meet the environmental protection requirements of today's society. That is, the industry really needs a halogen-free and lead-free adhesive composition which can improve and eliminate the disadvantages caused by the existing flexible printed circuit board materials, and can enhance the flame retardancy of the flexible printed circuit board and simplify the processing procedure. And reduce costs.

An object of the present invention is to provide a thermosetting resin composition which can be used as a binder for a flexible printed circuit board. The composition comprises an epoxy resin component, a flame retardant component, and a hardener component. Wherein, the epoxy resin component is selected from the group consisting of bisphenol A epoxy resin, novolac epoxy resin, and combinations thereof; the flame retardant component is selected from the group consisting of phosphorus-based flame retardants and The inorganic metal hydroxide and the combination thereof are treated in a compatible manner; the hardener component comprises a dicyandiamide compound and a low temperature catalyst. Further, the flame retardant component is contained in an amount of 50 to 200 parts by weight per 100 parts by weight of the epoxy resin component, and the hardener component is contained in an amount of 1 to 20 parts by weight per 100 parts by weight of the epoxy resin component.

Another object of the present invention is to provide a thermosetting resin composition which can be used as a protective film for a flexible printed circuit board. The composition comprises an epoxy resin component, a flame retardant component, and a hardener component. Wherein, the epoxy resin component is selected from the group consisting of bisphenol A epoxy resin, novolac epoxy resin, and combinations thereof; the flame retardant component is selected from the group consisting of phosphorus-based flame retardants and A combination of inorganic metal hydroxides and combinations thereof; the hardener component comprises a dicyandiamide compound and a low temperature catalyst of the imidazole type. Wherein, the content of the flame retardant component is 50 to 200 parts by weight per 100 parts by weight of the epoxy resin component, and the content of the hardener component is 1 to 20 parts by weight per 100 parts by weight of the epoxy resin component.

It is still another object of the present invention to provide a thermosetting resin composition which can be used for a flexible printed circuit board as an adhesive film. The composition comprises an epoxy resin component, a flame retardant component, and a hardener component. Wherein, the epoxy resin component is selected from the group consisting of bisphenol A epoxy resin, novolac epoxy resin, and combinations thereof; the flame retardant component is selected from the group consisting of phosphorus-based flame retardants and A combination of inorganic metal hydroxides and combinations thereof; the hardener component comprises a dicyandiamide compound and a low temperature catalyst of Lewis acid. Wherein, the content of the flame retardant component is 50 to 200 parts by weight per 100 parts by weight of the epoxy resin component, and the content of the hardener component is 1 to 20 parts by weight per 100 parts by weight of the epoxy resin component.

The thermosetting resin composition of the present invention has good material adhesion properties, flame retardancy and weather resistance, and the material does not contain halogen, which meets the requirements of green materials in today's environment.

The basic spirit and other objects of the present invention, as well as the technical means and preferred embodiments of the present invention, will be readily apparent to those skilled in the art.

The thermosetting resin composition of the present invention can be used in a flexible printed circuit board to provide adhesive properties. The composition comprises an epoxy resin component, a flame retardant component, and a hardener component.

The epoxy resin component suitable for use in the composition of the present invention may be selected from the following groups (but not limited thereto): bisphenol A epoxy resin, phenol novolac epoxy resin, and the foregoing The combination. Among them, a suitable bisphenol A type epoxy resin is one having 150 to 1000 epoxy equivalents and a weight average molecular weight ranging from 300 to 2,000. Here, depending on the molecular structure, the bisphenol A type epoxy resin can be further distinguished as: long chain bisphenol A type (L-Bis type) epoxy resin, medium chain bisphenol A type (M-Bis type) epoxy Resin and short-chain bisphenol A type (S-Bis type) epoxy resin. Among them, the long-chain bisphenol A type epoxy resin has an average molecular weight of 1200 to 2000, the medium chain bisphenol A type epoxy resin has an average molecular weight of 600 to 1200, and the short-chain bisphenol A type epoxy resin has an average molecular weight of 300 to 600. A suitable phenolic resin is one having an epoxy equivalent of 150 to 500 and a semi-solid at normal temperature.

Any convenient combination of the foregoing epoxy resins can be used in the compositions of the present invention. Preferably, a combination of two or more epoxy resins is employed to provide the epoxy resin composition desired in the present invention. For example (but not limited thereto), an epoxy resin mixture comprising a long chain, a medium chain, and a short chain bisphenol A type epoxy resin may be used, or a bisphenol A type epoxy resin and a phenolic resin may be used. A resin mixture of resins as an epoxy resin component required for the composition of the present invention.

The flame retardant component suitable for use in the compositions of the present invention is selected from the group consisting of phosphorus based flame retardants, affinity treated inorganic metal hydroxides, and combinations thereof. The flame retardant component is used in an amount of 50 to 200 parts by weight per 100 parts by weight of the epoxy resin component, preferably 50 to 100 parts by weight per 100 parts by weight of the epoxy resin component. Here, when a combination of a phosphorus-based flame retardant and an affinity-treated inorganic metal hydroxide is a flame retardant component of the present invention, it is preferred to use a phosphorus-based flame retardant and affinity-treated inorganic metal hydrogen. The weight ratio of the oxide is a mixture of 2:1 to 1:2.

Any phosphorus-based flame retardant which is soluble in a ketone solvent can be used in the present invention. The phosphorus-based flame retardant used in the present invention may be included, but not limited to, before being affected by the processing characteristics of the material: PX200, PSB100, trimethyl phosphate, triethyl phosphate (triethyl phosphate, TEP), tributyl phosphate, triphenyl phosphate (TPP), dimethyl methyl phosphate (DMMP), triphenyl phosphite ( Triphenyl phosphate), tricresyl phosphate, trixylenyl phosphate, cresyl phenyl phosphate, cresyl bis-2,6-dimethylphenyl Phosyl di-2 (6-xylenyl phosphate), diphenyl-2-metacryloyloxyethyl phosphate and aromatic condensed phosphate.

The affinity-treated inorganic metal hydroxide which is suitable for use as a flame retardant component in the present invention is an inorganic metal hydroxide particle having a surface covered with silane. Among them, unsubstituted or substituted decane can be used for this application. By way of example (but not limited thereto), a decyl halide such as triethylchlorosilane or dimethyldichlorsilane may be used to provide a coating treatment on the surface of the inorganic metal hydroxide particles. The flame retardant component. The application examples of the inorganic metal hydroxide may be, but not limited to, aluminum hydroxide, magnesium hydroxide, aluminum hydroxide magnesium carbonate hydrate, nickel hydroxide, titanium hydroxide, Barium hydroxide or the like may also be a combination of the foregoing hydroxides.

The hardener component contained in the composition of the present invention comprises a dicyandiamide compound and a low temperature type catalyst in an amount of 1 to 20 parts by weight per 100 parts by weight of the epoxy resin component, preferably 100 parts by weight of the epoxy resin. The ingredients are 4 to 10 parts by weight. Further, the content ratio of the dicyandiamide compound to the low-temperature catalyst in the hardener component is from 1:1 to 10:1, preferably from 4:1 to 6:1.

The "dicyandiamide compound" includes dicyandiamide and dicyandiamide adductS. By "low temperature catalyst" is meant an epoxy which can be accelerated at a lower temperature (i.e., below the ordinary epoxy hardening initiation temperature (about 150 ° C), such as a hardening temperature between 130 and 150 ° C). A catalyst for the hardening reaction of a resin. Different low temperature catalysts may be selected for use in the compositions of the present invention as desired. For example, optional low temperature catalysts include, but are not limited to, imidazole low temperature catalysts and Lewis acid low temperature catalysts.

Specifically, if an imidazole-based low-temperature catalyst is used in the composition of the present invention, in addition to providing the subsequent performance, the formed material layer can be directly used as a cover film for protecting the printed circuit board. Here, the substituent on the imidazole is also not subject to any limitation. For example, imidazoles may be used, but not limited to, 2-methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole (2-ethyl-4-methylimidazole), 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole , 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole (2-phenyl) -4,5-dihydroxymethylimidazole), and 2-phenyl-4-methyl-5-hydroxymethylimidazole.

Further, if a Lewis acid is used as the low-temperature type catalyst in the composition of the present invention, the material layer provided has particularly good adhesive properties. Any suitable Lewis acid type low temperature catalyst can be employed in the compositions of the present invention. Preferably, a borofluoride is used in the composition of the present invention, by way of example (but not limited thereto): boron trifluoride monoethylamine complex (BF _{3 .} MEA) and Boron trifluoride triethylamine (BF _{3 .} Et ₃ N).

Optionally, an aromatic amine compound may be further included in the hardener component. By way of example and not limitation, the following aromatic amines may be employed: diaminodiphenyl methane (DDM), such as 3,3-diaminodiphenyl hydrazine (3,3'- Diaminodiphenyl sulfone, 3,3'-DDS) and 4,4-diaminodiphenyl sulfone (4,4'-DDS) diaminodiphenyl sulfone (DDS) Such as 4,4'-diaminobenzophenone (4,4'-DBP) diaminobenzophenone (DBP), 3, 3', 5, 5'-tetramethyl-4,4'-diaminodiphenyl sulfone (TMDS), and combinations thereof. The aromatic amine compound may be included in the hardener component in an amount of from 0 to 70% by weight.

The compositions of the invention can be used in a conventional manner. For example, an inorganic filler such as aluminum hydroxide or magnesium hydroxide may be first dispersed in a benzene solvent and treated as a dispersion under ball milling. An elastomer such as butadiene (BN) rubber and a flame retardant component are added to the dispersion, and the mixture is mixed to a certain extent by stirring at a high speed or shaking. Thereafter, an epoxy resin component solution such as a ketone (e.g., methy ethyl ketone) is added as a solvent, and stirring is continued in the same manner to obtain a solution. In addition, the hardener component and the low-temperature catalyst are dissolved in a protic solvent such as dimethyl formamide or methyl ethyl cellulose, stirred and dissolved, and filtered to obtain another Solution. The above two solutions are mixed in a certain ratio as needed, and the viscosity is adjusted as needed to obtain a binder solution having a solid content of 35 to 45 weight percent.

Thereafter, the above adhesive solution may be applied to the carrier film by a thick film coating method using a doctor blade or a roller, and then baked at a temperature of 100 ° C to 140 ° C for 3 to 5 minutes using an electric heating circulating oven until a semi-hardened state is exhibited (B -stage). Thereafter, it is bonded to the release paper by a roller type laminating machine, and then laminated to a hot plate having a temperature of 50 to 80 ° C, which is then preheated for 0 to 5 seconds, and formed for 60 to 120 seconds. The pressure is 160 to 190 ° C, the pressure is 75 to 120 kg/cm ² , the hardening temperature is in the range of 150 to 190 ° C, and the hardening time is 1 to 3 hours to shape the material. Here, if the carrier film is a non-release type polyamide (PI) film, the laminated product is a protective layer which can be used as a cover film, and if the surface is a release-treated polyethylene terephthalate The ester (PET) film can be bonded to an adhesive layer.

The invention is further illustrated by the following specific embodiments. Among them, the evaluation methods of each composition were as follows: (1) Peel Strength test: According to the IPC TM 650 2.4.9 method, a test piece of 1 cm width was cut out, and the subsequent strength was tested by a tensile machine.

(2) Solder-ability test: According to the IPC TM 650 2.4.13 method, the test piece is placed in a high temperature environment (such as a soldering furnace) for a period of time, and the change is observed.

(3) Anti-Chemicals test: Test pieces were prepared and tested according to the IPC TM 650 2.3.2 method.

(4) Effluent or Resin Flow test: A test piece was prepared and tested according to the IPC TM 650 2.3.17.1 method.

(5) Flammability test: A test piece was prepared according to UL-94 certified V-0, and a flame retardance tester was used for the flame-retardant test.

(6) Surface Resistance test: A test piece was prepared according to the IPC TM 650 2.5.17 method, and a surface impedance test was performed using a high-impedance machine.

(7) Reliability test: The test piece was placed in an environment of a constant temperature of 85 ° C and a constant humidity of 85% RH to measure characteristics such as adhesion strength and heat resistance of the test piece.

Several embodiments of the present invention are shown in the following list, and Examples 1 to 4 (P1-P4) are illustrative of the use of the compositions of the present invention in a protective layer, and Examples 5 and 6 (P5-P6) are directed to the compositions of the present invention. For the application of adhesives.

In P1, the solution prepared according to the above preparation is mixed in an appropriate ratio, and then coated on a 12.5 micron polyimide film (or polyethylene terephthalate film release treatment), and after drying, the film thickness is At 20 microns, the release paper is a protective layer or an adhesive layer after heat bonding. P2, P3 and P4 change the type of epoxy resin in the epoxy resin component, and change the dicyandiamide compound (for the dicyandiamide adduct D1 of AH154, such as AJINOMOTO), or dicyandiamide Amount of amine D2) and aromatic amine compound added.

P5 and P6 are available with different hardeners. Among them, P5 uses dicyandiamide (D2) and dicyandiamide adduct (D1) as hardeners; P6 hardener is another embodiment that changes the D1 and D2 contents and uses different catalysts.

Note: 1.L: long chain bisphenol A epoxy resin. 2. M: medium chain bisphenol A type epoxy resin. 3.S: Short-chain bisphenol A epoxy resin. 4. IPA: isopropanol. 5. PET-E: The product is PET-200 film of J. Lin Enterprise Co., Ltd. 6. PET-L: The product is PET-38AL-5 film of Lintec Corporation. 7. DMF: dimethyl formamide.

It can be seen from the above examples that the composition of the present invention contains no halogen, and the provided material layer has good flame retardancy and weather resistance in addition to the proper adhesion, and can eliminate the materials used in the conventional flexible printed circuit board. Causes problems.

The above-described embodiments are only intended to illustrate the embodiments of the present invention, and to explain the technical features of the present invention, and are not intended to limit the scope of the present invention. Any changes or equivalents that can be easily made by those skilled in the art are within the scope of the invention. The scope of the invention should be determined by the scope of the claims.

Claims (22)

A thermosetting resin composition comprising: an epoxy resin component selected from the group consisting of bisphenol A epoxy resin, novolac epoxy resin, and combinations thereof; and a flame retardant component selected from the group consisting of: a phosphorus-based flame retardant, an affinity-treated inorganic metal hydroxide, and a combination thereof; and a hardener component comprising a dicyandiamide compound and a low-temperature catalyst, wherein the flame retardant component The content is 50 to 200 parts by weight per 100 parts by weight of the epoxy resin component, and the content of the hardener component is 1 to 20 parts by weight per 100 parts by weight of the epoxy resin component. The thermosetting resin composition according to claim 1, wherein the hardener component is contained in an amount of 4 to 10 parts by weight per 100 parts by weight of the epoxy resin component. The thermosetting resin composition according to claim 1, wherein the flame retardant component is contained in an amount of from 50 to 100 parts by weight per 100 parts by weight of the epoxy resin component. The thermosetting resin composition according to claim 1, wherein the bisphenol A type epoxy resin has an epoxy equivalent in a range of from 150 to 1,000, and the phenolic resin has an epoxy equivalent of from 150 to 500. The thermosetting resin composition according to claim 4, wherein the bisphenol A type epoxy resin has a weight average molecular weight ranging from 300 to 2,000. The thermosetting resin composition according to claim 5, wherein the resin component is a bisphenol A type epoxy resin, and comprises a long-chain bisphenol A type epoxy resin, a medium chain bisphenol A type epoxy resin, and/or Short-chain bisphenol A epoxy resin. The thermosetting resin composition according to claim 1, wherein the weight ratio of the phosphorus-based flame retardant to the affinity-treated inorganic metal hydroxide is from 2:1 to 1:2. The thermosetting resin composition according to claim 1, wherein the phosphorus-based flame retardant is soluble in a ketone solvent. The thermosetting resin composition according to claim 1, wherein the phosphorus-based flame retardant comprises an organic phosphate. The thermosetting resin composition according to claim 1, wherein the affinity-treated inorganic metal hydroxide is an inorganic metal hydroxide particle having a surface covered with a decane. The thermosetting resin composition according to claim 10, wherein the metal hydroxide is aluminum hydroxide. The thermosetting resin composition according to claim 1, wherein the dicyandiamide compound is dicyandiamide. The thermosetting resin composition according to claim 1, wherein the dicyandiamide compound is an adduct of dicyandiamide. The thermosetting resin composition according to claim 1, wherein the low temperature type catalyst is an imidazole. The thermosetting resin composition according to claim 1, wherein the low temperature type catalyst is a Lewis acid. The thermosetting resin composition according to claim 1, wherein the weight ratio of the dicyandiamide compound to the low temperature type catalyst is from 1:1 to 10:1. The thermosetting resin composition according to claim 1, wherein the weight ratio of the dicyandiamide compound to the low temperature type catalyst is from 4:1 to 6:1. The composition of claim 1 wherein the hardener component further comprises an aromatic amine compound. The thermosetting resin composition according to claim 18, wherein the aromatic amine compound is selected from the group consisting of 3,3'-diaminodiphenyl sulfone (3,3'-). DDS), 4,4'-diaminodiphenyl sulfone (4,4'-DDS), 4,4'-diaminobenzophenone, 4,4'-diaminobenzophenone, 4,4'DBP),3,3'5,5'-Tetramethyl-4,4'-diaminodiphenyl sulfone (3,3'5,5'-tetramethyl-4,4'-diaminodiphenyl sulfone , TMDS), and combinations thereof. The thermosetting resin composition of claim 14, which is for providing a protective layer. The thermosetting resin composition of claim 15 which is for providing an adhesive layer. The thermosetting resin composition according to claim 1, which is used for a flexible printed circuit board.