Research On Preparation And Application Of Metallization On The Surface Of Flexible Epoxy Resin Substrates

As technology of electronics has considerably developed,electronic devices facilitate and have become an integral part of daily life.Meanwhile,electromagnetic radiation generated by electronic devices not only brings great harm to precision instrument,military equipment and aerospace engineering,but also adversely affect human health.Therefore,electromagnetic radiation has been regarded as a serious public pollution issue,and it is obvious that the demand for practical materials with high efficiency toward electromagnetic radiation suppression has become a mainstream research topic.At present,the most commonly used method of electromagnetic shielding in practical applications is the coating of metal films on the surface of organic polymeric substrates.Flexible epoxy resin is one of the most ideal substrates to be used in the electromagnetic shielding material because of its low cost,flexible,chemical stability and good process ability.Flexible epoxy resin has many challenges that hinder their application in electromagnetic shielding material,such as difficulty in surface metalizing and poor adhesion between metal layer and substrate.This paper will provide a feasible solution for preparation of metallization on the surface of flexible epoxy resin substrates.Research is as follow.?1?This paper has conducted pretreatment on flexible epoxy resin substrates to appropriate improve the surface roughness and hydrophilicity,can provide mechanical bonding points for metal to bond with substrates.Then,this paper has conducted modified grafting on flexible epoxy resin substrates using modified grafting solution with Na₂S₂O₃.Functional groups(S₂O₃^2-)which can complexation with metal ions has been successfully modified on the surface of substrates by the ring-opening reaction of with the epoxy group.The adhesion between the deposited metal layer and the surface of the flexible epoxy resin substrate is further improved.?2?This paper has obtained a catalytic planted layer of silver on modified flexible epoxy resin substrates through immersed in a silver-based solution type catalytic ink.After a series of comparative experiments,it turns out that the catalytic planted layer has good adhesion with modified flexible epoxy resin substrates,and it could provide the catalytic active center for the subsequent electroless deposition.?3?To fabricate deposited copper layer on modified flexible epoxy resin substrates,electroless deposition has been introduced.After a series of different analysis and characterization,it proves that the deposited copper layer fabricated by this paper has a good metallic luster,a dense surface morphology,high purity,excellent crystallinity and excellent electrical conductivity?resistivity is only 1.33 times of bulk copper?,and the deposited copper layer gets a highest score according to adopted standard and has a good adhesion to the modified substrate.?4?The deposited copper layer on flexible epoxy resin substrate through our process has an excellent electromagnetic interference shielding effectiveness of greater than 60 dB in the frequency range from 4 GHz to 18 GHz,and can shield greater than99.9999%of electromagnetic waves at high frequencies.These results above imply that the process is simply and highly reliable by this paper can fabricate deposited copper layer with high quality,strong adhesion,excellent electromagnetic shielding effectiveness in a low-cost and highly efficient way,which makes it very promising to be applied to electromagnetic shielding materials.