Patent Application
20070299218
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings:
The present invention pertains to the field of electronic materials. More particularly, the present invention provides a composition of a dimmer-acid modified thermosetting epoxy resin system and a novel thermosetting epoxy resin film prepared by using such composition. The dimmer-acid modified thermosetting epoxy resin film formed according to the recipe of the present invention exhibits superior flexibility, chemical resistance, and solder resistance, which is particularly suited for electronic applications such as packaging, substrate bonding, and so on.
The novel thermosetting epoxy resin film prepared by using the composition of the present invention is applicable to a variety of industry fields, but is particularly suited for flexible PCB industry. For example, the novel thermosetting epoxy resin film prepared by using the composition of the present invention can replace the conventional coverlay and be used to as solder mask for the protection of the surface of the flexible PCB.
Alternatively, the novel thermosetting epoxy resin film prepared by using the composition of the present invention can replace the conventional carboxylterminated butadiene acrylonitrile (CTBN)-modified epoxy resin system and be used as adhesive of a protection film. The novel thermosetting epoxy resin film prepared by using the composition of the present invention can be used as bonding agent for flexible PCB and is applied to interface between layers of the flexible PCB. The novel thermosetting epoxy resin film prepared by using the composition of the present invention can be used as adhesive on a reinforcement film.
The present invention provides a novel composition of a dimmer-acid modified epoxy resin system and dimmer-acid modified epoxy resin film thereof. The dimmer-acid modified epoxy resin film formed according to the recipe of the present invention exhibits superior flexibility, chemical resistance, and solder resistance, which is particularly suited for electronic applications such as packaging, substrate bonding.
After admixing with proper additives and after curing, the dimmer acid modified flexible epoxy resin system exhibits superior flexibility, chemical resistance, and solder resistance. The novel dimmer acid modified flexible epoxy resin is applicable to flexible PCB and used as a protection solder mask with improved flexibility and chemical resistance and reduced cost. The preparation of the novel dimmer acid modified flexible epoxy resin system and its use are also simplified.
The novel dimmer acid modified flexible epoxy resin system can be used as good bonding agent and can be used to bond dielectric layer or bonding layer of either hard board PCB or flexible PCB. The novel dimmer acid modified flexible epoxy resin system has improved adhesion to both copper and polyimide.
Dimer acid (or dimerized fatty acid), which can be dissolved in many kinds of organism, is a kind of duality acid polymer from fatty acid and it is over 2 carboxyl groups. Dimer acid has good heat stability and will not harden at low temperatures. Dimmer-acid is mainly used in polyamide resin synthesis and manufacture, and as fuel oil agent, lubricant agent, etc., and the dimmer-acid modified epoxy resin film exhibits superior flexibility, chemical resistance, and solder resistance.
Examples of commercially available dimmer-acid modified epoxy resin includes but not limited to NPER-172 (Dimer Acid modified DGEBA) available from Nanya Plastics Corp. (NPER-172 is a product name of Nanya Plastics Corp.), HyPox DA323 (Dimer Acid Adducted to an Epoxidized Bisphenol A Resin; CAS No. 67989-52-0) available from CVC Specialty Chemicals Inc., and ERYSYS GS-120 (Dimer Acid Glycidyl Ester; CAS No. 68475-94-5) available from CVC Specialty Chemicals Inc., YD-172 available from Tohto Kasei Co., Ltd., and YD-271 or YD-272 available from Eptec.
In order to adjust the reactivity and/or physical properties, the aforesaid dimmer-acid modified epoxy resins may be employed singly or combined with other types of additive resins. For example, the aforesaid other types of additive resins may be selected from the group consisting of Bisphenol-A epoxy resins, Brominated Bisphenol-A epoxy resins, Bisphenol-F epoxy resins, long-chain Bisphenol-A epoxy resins, long-chain Bisphenol-F epoxy resins, CTBN modified epoxy resins, carboxylated acrylonitrile-butadiene rubber, and carboxylated acrylic rubber.
To obtain adequate softness, the content of the dimer acid modified thermosetting epoxy resin preferably ranges between 40-100 phr (pars per hundred parts) of total weight of the resin mixture, while the aforesaid additive resin preferably ranges between 60-0 phr of total weight of the resin mixture.
The aforesaid resins may be mixed with proper amount of hardening agent and catalysts. For example, the hardening agent may include dicyandiamide, phenol-formaldehyde resins, melamine-formaldehyde resins, polyamides, polysulfides, amidoamines, and aromatic amines. Assuming that the total weight of the prepared starting resin mixture is 100 phr, the content of hardening agent preferably ranges between 1-30 phr. According to this invention, the aforesaid catalyst may be amines, imidazoles, or BF3-MEA ranging between 0.1-10.0 phr on a scale of total resin weight of 100 phr.
Furthermore, depending on the requirements and purposes of use, other additives such as rheological agents, thixotropic reagent, fumed silica, defoamers, leveling agents, organic solvents, pigments, fire retardants and inorganic fillers may be added.
In the three experiments (Exp. 1˜Exp. 3), the weight of LG LER-153F (brominated epoxy resin) increases while the weight of HyPox DA 323 decreases. When the dimer acid adducted bisphenol-A resin (HyPox DA 323) is employed singly and does not combine with other types of additive resins such as LG LER-153F as in the Exp. 1 case, it is softer. However, the surface of the resin film is prone to scratching due to reduced hardness. Properly adding other harder epoxy resins such as brominated epoxy resins, bisphenol-A or bisphenol-F series resins can obtain a balance in physical properties.
Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.
