A kind of ultra-thin PI cover layers and preparation method thereofTechnical field
The present invention relates to covering technical field of membrane, in particular it relates to a kind of ultra-thin PI cover layers and preparation method thereof.
Background technology
In recent years, developing rapidly with smart mobile phone, user's pursuit mobile electronic product is lightening, and display surface is big, work(Can be more.This promotes manufacturer to require that the functional integration of product is higher, and wiring board material is thinner, thinner and more layers, so thatRealize the design requirement of final products.However, material more and more thinner increases production difficulty, particularly flex circuit application base materialThinning so that base material is more easily rupturable, production process yields declines, production efficiency reduction.Therefore, holding base material thickness is had only notJust, the thickness of cover layer is reduced.
Covering film thickness is determined by PI film thicknesses and bondline thickness.Bondline thickness covers type by the thickness and cover layer of Copper FoilProperty is together decided on., can be because glue filling not enough produces bubble when wiring board covers epiphragma producing if reducing bondline thickness.CauseThis bondline thickness is arbitrarily to reduce.If reducing PI thickness, it can not only make cover layer thickness thinning, and can carryHigh cover layer covers type, so as to reduce the thickness of glue-line.
The production method of traditional cover layer, is one layer of glue of painting on PI films, then compound as cover layer with release liners.WhenPI thickness is more than 12 μm, when PI films have certain very levelling, thereon gluing and with release liners it is compound wait to operate more holdEasily；But work as PI film thicknesses and be less than 12 μm, or even when being reduced to 7 μm or 5 μm, PI films are very soft, it is easy to fold, PI films are almostIt is difficult to keep smooth, gluing is easily deformed thereon, the bad situation of contraposition, operation also easily occurs with release liners compound tenseDifficulty is big, low production efficiency.
Therefore, the operational problem when PI thickness of cover layer is reduced to 7 μm or 5 μm is manufacturer's skill urgently to be resolved hurrilyArt problem.
The content of the invention
In order to solve the above-mentioned technical problem, the invention provides a kind of ultra-thin PI cover layers and preparation method thereof, solvePI film thicknesses are less than 12 μm, or even operational problem when being reduced to 7 μm or 5 μm.
Technical scheme is as follows：A kind of ultra-thin PI cover layers, including PI films and the release liners located at its side, withAnd viscose glue oxidant layer therebetween, it is characterised in that the PI film thicknesses are 3-10 μm；The opposite side of the PI films is additionally provided with lowViscose glue pet vector film, the low viscose glue pet vector film includes the PET film that thickness is 10-50 μm and bonds the PI films and describedThe low adhesive of PET film；The off-type force of the low adhesive and the PET film be more than the low adhesive and the PI films fromType power.
The low adhesive thickness is 2-20 μm, and the low adhesive is 2-30 grams/25mm with the off-type force of the PI films.
It is preferred that the low adhesive thickness is 5-15 μm, the low adhesive is 10-25 with the off-type force of the PI filmsGram/25mm.
The low adhesive is made up of following each component by weight：
End carboxyl nitrile rubber 25-35 parts by weight；90-105 parts of 1001 epoxy resin of bisphenol-A, wherein solids content 60%；15-20 parts of dicyandiamide, is dissolved in DMF solution, wherein DICY dicyandiamides concentration is 10%；2- ethylmethylimidazoliums 0.03-0.06Part；50-120 parts of butanone.
The low adhesive is 2-30 grams/25mm with the off-type force of the PI films, and glue overflow amount is less than 0.12mm.
The low viscose glue pet vector film is Taiwan get Wan Li companies commodity TWL-33.
The low adhesive contains acrylic resin or polyurethane resin, and the cohesive force of the low adhesive and the PI films is2-30 grams/25mm, glue overflow amount is less than 0.12mm.
The preparation method of the ultra-thin PI cover layers, comprises the following steps：
(1) preparation of low viscose glue pet vector film：Low adhesive is prepared, takes 10-50 μm of PET film to carry out sided corona treatment, thenLow adhesive is coated on the PET film by sided corona treatment, by drying, solidification；Should during control the low adhesive withThe off-type force of the PET film is more than the off-type force of the low adhesive and the PI films, obtained low viscose glue pet vector film；
(2) preparation of carrier PI composite membranes：The ultra-thin PI of above-mentioned low viscose glue pet vector film and 5-15 μm is combined,Combined temp is less than the softening point of low viscose glue, and carrier PI composite membranes are made；
(3) carrier PI composite membranes and release liners are compound：Coating modified epoxy or acrylic acid on face are combined in carrier PIGlue, drying, then it is compound with release liners, obtain ultra-thin PI cover layers.
When the solution of low adhesive is coated on the PET film Jing Guo sided corona treatment, the dry glue thickness for controlling low viscose is2-20 microns；By drying, after solidification, it is 2-30 grams/25mm with the cohesive force of PI films to control low viscose glue.
When preparing wiring board with ultra-thin PI cover layers of the present invention, the ultra-thin PI cover layers are attached to etching through aligning vacationIn copper-clad plate, after fast pressure, the low viscose glue pet vector film is removed, is only increased " removing the low viscose glue pet vector film "This procedure, it is other to be carried out by normal procedure.
Ultra-thin PI cover layers of the present invention and preparation method thereof are in the case where base material thickness is constant, in PI film thicknesses dropAt as little as less than 12 μm, increase the very levelling of PI films by setting low viscose glue pet vector film, it is indeformable in gluing thereon, easilyContraposition efficiency between operation, lifting cover layer and wiring board, is easy to implement automatic aligning, improves base material wet production mistakeThe product yield and production efficiency of journey.
Brief description of the drawings
Fig. 1 is the structural representation of ultra-thin PI cover layers of the present invention.
Embodiment
Below by embodiment to further illustrating the present invention, to help to be better understood from present disclosure,But these embodiments are not in any way limit the scope of the present invention.
Reference picture 1, a kind of ultra-thin PI cover layers, including PI films 10 and the release liners 11 located at its side, and the two itBetween viscose glue oxidant layer 12.The opposite side of the PI films 10 is additionally provided with low viscose glue pet vector film 20.The low viscose glue pet vector film 20It is 10-50 μm of PET film 21 and the low adhesive 22 of the bonding PI films 10 and the PET film 21 including thickness.It is described low viscousJelly 22 is more than the off-type force of the low adhesive 22 and the PI films 10 with the off-type force of the PET film 21.
The thickness of PI films 10 is 3-10 μm.
The thickness of low adhesive 22 is 2-20 μm, and the low adhesive 22 is 2-30 with the off-type force of the PI films 10Gram/25mm.
It is preferred that the thickness of low adhesive 22 is 5-15 μm, the off-type force of the low adhesive 22 and the PI films 10For 10-25 grams/25mm.
Embodiment 1：
A kind of preparation method of ultra-thin PI cover layers, comprises the following steps：
(1) preparation of low viscose glue pet vector film：
Low adhesive is prepared, the low adhesive includes following each component by weight：End carboxyl nitrile rubber 30Parts by weight；1,001 100 parts of bisphenol A epoxide resin, wherein solids content 60%；18 parts of dicyandiamide, is dissolved in DMF solution, whereinDICY dicyandiamides concentration is 10%；0.05 part of 2- ethylmethylimidazoliums；120 parts of butanone.End carboxyl nitrile rubber is dissolved in fourthIn ketone, bisphenol A epoxide resin 1001 is added, the ethylmethylimidazolium of dicyandiamide 1,2 is mixed, and obtains low adhesive；
Take 25 μm of PET films to carry out sided corona treatment, then low adhesive is coated on the PET film by sided corona treatment, controlThe low dried thickness of adhesive is 5 μm, solidifies 1-2 hours by 150 DEG C of drying 5min, then by 160-170 DEG C, obtainsLow viscose glue pet vector film, the low viscose glue pet vector film is 10 grams/25mm with PI films cohesive force；
(2) preparation of carrier PI composite membranes：Above-mentioned low viscose glue pet vector film and 5 μm of the used north machine of ultra-thin PI films are answeredClose, 80-120 DEG C of combined temp, carrier PI composite membranes are made；
(3) carrier PI composite membranes and release liners are compound：It is combined in carrier PI on face and coats modified epoxy glue, is appliedLayer dry thickness control is at 10 μm, drying, then compound with release liners, obtains ultra-thin PI cover layers.
Above-mentioned ultra-thin PI cover layers are cured 10 hours by 50 DEG C again, glue overflow amount is controlled in below 0.12mm；Take base materialTPI thickness is 20 μm of double side flexible copper coated board, is etched into special flex circuit application, the two-sided ultra-thin PI cover layers covered after curingProtection circuit, after fast pressure, removes the low viscose glue pet vector film, solidifies, wiring board is prepared through traditional handicraft.The lineRoad board finished product base material thickness is 15*2+20=50 μm.
Embodiment 2：
A kind of preparation method of ultra-thin PI cover layers, comprises the following steps：
(1) preparation of low viscose glue pet vector film：Low viscose glue is applied from get Wan Li science and technology purchases PR-SS50N-01-1CM101PET film, off-type force is 5 grams/25mm, removes diaphragm, obtains low viscose glue pet vector film；
(2) preparation of carrier PI composite membranes：Above-mentioned low viscose glue pet vector film and 5 μm of the used north machine of ultra-thin PI films are answeredClose, 80-120 DEG C of combined temp, carrier PI composite membranes are made；
(3) carrier PI composite membranes and release liners are compound：It is combined in carrier PI on face and coats modified epoxy glue, is appliedLayer dry thickness control is at 15 μm, drying, then compound with release liners, obtains ultra-thin PI cover layers.
Above-mentioned ultra-thin PI cover layers are cured 13 hours by 50 DEG C again, glue overflow amount is controlled in below 0.12mm；Take base materialTPI thickness is 20 μm of double side flexible copper coated board, is etched into special flex circuit application, the two-sided ultra-thin PI cover layers covered after curingProtection circuit, after fast pressure, removes the low viscose glue pet vector film, solidifies, wiring board is prepared through traditional handicraft.The lineRoad board finished product base material thickness is 10*2+20=60 μm.
Embodiment 3：
A kind of preparation method of ultra-thin PI cover layers, comprises the following steps：
(1) preparation of low viscose glue pet vector film：
Low adhesive is prepared, the low adhesive includes following each component by weight：End carboxyl nitrile rubber 30Parts by weight；1,001 100 parts of bisphenol A epoxide resin, wherein solids content 60%；18 parts of dicyandiamide, is dissolved in DMF solution, whereinDICY dicyandiamides concentration is 10%；0.05 part of 2- ethylmethylimidazoliums；120 parts of butanone.End carboxyl nitrile rubber is dissolved in fourthIn ketone, bisphenol A epoxide resin 1001 is added, the ethylmethylimidazolium of dicyandiamide 1,2 is mixed, and obtains low adhesive；
Take 18 μm of PET films to carry out sided corona treatment, then low adhesive is coated on the PET film by sided corona treatment, controlThe low dried thickness of adhesive is 5 μm, solidifies 1-2 hours by 150 DEG C of drying 5min, then by 160-170 DEG C, obtainsLow viscose glue pet vector film, the low viscose glue pet vector film is 10 grams/25mm with PI films cohesive force；
(2) preparation of carrier PI composite membranes：Above-mentioned low viscose glue pet vector film and 8 μm of the used north machine of ultra-thin PI films are answeredClose, 80-120 DEG C of combined temp, carrier PI composite membranes are made；
(3) carrier PI composite membranes and release liners are compound：It is combined in carrier PI on face and coats modified epoxy glue, is appliedLayer dry thickness control is at 12 μm, drying, then compound with release liners, obtains ultra-thin PI cover layers.
Above-mentioned ultra-thin PI cover layers are cured 10 hours by 50 DEG C again, glue overflow amount is controlled in below 0.12mm；Take base materialTPI thickness is 20 μm of double side flexible copper coated board, is etched into special flex circuit application, the two-sided ultra-thin PI cover layers covered after curingProtection circuit, after fast pressure, removes the low viscose glue pet vector film, solidifies, wiring board is prepared through traditional handicraft.The lineRoad board finished product base material thickness is 20*2+20=60 μm.
Comparative example 1
There is no PT carrier films to contrast for slim PI, by the slim PI of traditional mode of production mode, take the PI films that thickness is 5 μm,Cover layer modified epoxy glue is applied on PI faces, the dry thick control of coating after drying, is combined with release liners and covered at 10 μmEpiphragma.
Cover layer is cured 10 hours in 50 DEG C of 50 DEG C of processes, glue overflow amount is controlled in 0.10mm.
The double side flexible copper coated board for taking base material TPI thickness to be 20 μm, is etched into special flex circuit application, two-sided to cover after curingUltra-thin PI cover layers protection circuit, after fast pressure, solidification prepares wiring board through traditional handicraft.The circuit board finished product baseMaterial thickness is 15X2+20=50 μm.
Comparative example 2
The specifications of cover layer SF05C 0515 of Shengyi Science and Technology Co., Ltd, Guangdong that in the market buying is obtained are taken, itsPI film thicknesses are 12.5 μm, and glue thickness is 15, and glue overflow amount control is 0.12mm, as a comparison.
It is 12.5 μm of double side flexible copper coated board to take base material TPI thickness, is etched into special flex circuit application, two-sided coated with coveringEpiphragma protection circuit, after fast pressure, solidification prepares wiring board through traditional handicraft.The circuit board finished product base material thickness is27.5X2+12.5=67.5 μm.
The present inventor tests the performance of embodiment 1-3 and comparative example 1-2 double side flexible copper coated board, method of testing and itemMesh is as follows：
Cover layer operability is evaluated：Cover layer is bored into four positioning holes, it is mobile to contain carrier film or nothing after release liners are torn offCarrier film PI band glue-line align in the circuit board, contrast contraposition difficulty, easily contraposition for it is excellent, good, in, difference evaluated.
Cover layer covers type evaluation：After the release liners of cover layer are torn off, it is pressed on specific line pattern, by 180DEG C/precompressed in 60 seconds, then apply 100Mpa, after pressing in 180 DEG C/120 seconds, examine whether circuit is compacted bubble-free, if bubble-freeThen to be qualified.
PET releases and the no evaluation of cull：After the completion of the experiment that cover layer is covered to type evaluation, after PET is torn off, ifEasily tear off, whether there is cull to stay in above PI films after tearing.
Testing result record such as table 1.
The performance test results of the embodiment 1-3 of table 1 and comparative example 1-3 double side flexible copper coated board compare
Above content is to combine specific preferred embodiment further description made for the present invention, it is impossible to assertThe specific implementation of the present invention is confined to these explanations.For general technical staff of the technical field of the invention,On the premise of not departing from present inventive concept, its framework form can be flexible and changeable, can be with subseries product.Simply make someSimple deduction or replace, should all be considered as belonging to the scope of patent protection that the present invention is determined by the claims submitted.