Embodiment
Fig. 1 is the cross-sectional structure figure of double-layer polyester resin molding aluminium foil, and it is the raw material that are used to make electronics enclosure.This resin molding aluminium foil 10 is to produce by flow process shown in Figure 2.As shown in Figure 1, comprise aluminium foil 2 and the double-layer polyester film of being made up of first polyester resin layer 4 and second polyester resin layer 6 in the resin molding aluminium foil 10, this double-layer polyester film is rolled in the one or both sides of aluminium foil 2.In example shown in Figure 1, the double-layer polyester resin molding only is attached to the wherein one side of aluminium foil 2.Wherein first polyester resin layer 4 is attached directly on the aluminium foil 2, and second polyester resin layer 6 is attached on first resin bed 4.In order to increase the adhesive force between first polyester resin layer 4 and the aluminium foil 2, can carry out special processing to the surface of aluminium foil, so that between the aluminium foil 2 and first polyester resin layer, form a layer 8.
First polyester resin layer 4 and second polyester resin layer 6 are made by copolyesters.Can add acid ingredient as its comonomer in copolyesters, the acid ingredient here comprises aromatics (dicarbonic) acid, for example isophathalic acid, phthalandione and naphthalene (dicarbonic) acid; Also comprise aliphat (dicarbonic) acid, for example aliphatic acid, azelaic acid and decanedioic acid and other alternative (dicarbonic) acid.Can also add pure constituents in copolyesters, the pure constituents here comprises (alithatic) glycol, for example dimethyl ethylene glycol, diethylene glycol (DEG), butanediol and hexylene glycol; Also comprise alternative glycol, for example cyclohexane (dimethanol).These comonomers can use separately, perhaps use in the mode of two or more combinations.Wherein must control the copolyreaction ratio of acid ingredient and alcohol component, just can make the fusing point of the film of making drop on the fusing point of first polyester resin layer 4 in the melting range of second polyester resin layer 6.
First polyester resin layer 4 wherein preferably is lower than 250 ℃ copolymerization ethylene glycol terephthalate by fusing point and makes.If the use fusing point is higher than 250 ℃ polyester resin film as first polyester resin layer 4, then the adhesive force between polyester resin film and the aluminium foil 2 can reduce, cause resin molding and aluminium foil to be difficult to mutual close adhesion, in drawing process, undesirable polyester resin film is peeled off layering from aluminium foil 2 situation also may take place.
Second polyester resin layer 6 preferably is higher than 250 ℃ and include PETG and make as the copolymerization of ethylene of its main repetitive by fusing point.If the use fusing point is lower than 250 ℃ polyester resin film as second polyester resin layer 6, then drawing processing or capacitor is being installed in the on-chip hot procedure, polyester resin film may produce part and peel off the situation of layering or damage and deterioration.
Aluminium foil 2 the most handy aluminium or with purity be higher than 95% and the well behaved almag steel of press-stretched make.
In the prior art, in order to improve the adhesive force between aluminium foil 2, the polyester resin layer 4 and 6, polyester resin layer 4 and 6 is being rolled before on the aluminium foil 2; Aluminium foil 2 is through chromate, phosphate or the chemical treatment of chromium phosphate solution, forms one on its surface and is used for the chromium coating 8 that contacts with resin bed.At present, also the available energy titanate or the zirconates that reduce environmental pollution to a certain extent comes aluminium foil 2 is carried out chemical treatment.This chemical treatment layer 8 and resin molding form a hydroxylation tack coat to improve the adhesive force between aluminium foil 2 and the polyester resin layer 4.In addition, in order to improve the adhesive force between the aluminium foil 2 and first polyester resin layer 4, can handle aluminium foil 2 with a kind of corrosive solution.After the surface of aluminium foil 2 carried out roughened with acid or aqueous slkali, first polyester resin layer 4 was attached on the aluminium foil 2 with desirable surface roughness the time, and adhesive force between the two can increase greatly.
But, adopt the method that draws after the heat treatment that the back will be talked about among the present invention, even if above-mentioned chemical treatment is not carried out on the surface of aluminium foil 2, the interface adhesive force between aluminium foil 2, the resin bed 4 and 6 also can significantly improve.Certainly, but the method use in conjunction to drawing after the surface treatment of aluminium foil 2 and the heat treatment of the present invention, so that outstanding interface binding power to be provided.
To introduce the production method of double-layer polyester resin molding aluminium foil hereinafter.
Fig. 2 is a process chart, wherein shows the serial flow process of the double-layer resin film aluminium foil shown in the shop drawings 1, and the flow process of producing shell with this resin molding aluminium foil.
In this production procedure, aluminium foil and double-layer polyester resin molding are rolled into the reel shape, consider productivity ratio, for the double-layer polyester resin molding volume 20 that comprises first and second polyester resin layers is attached on the aluminum foil coil 10a, use traditional hot attachment techniques here.
Aluminum foil coil 10a specially is placed on the unreel equipment (not drawing in the drawings) carries out unreel, and carries out preliminary treatment, as washing, surface treatment, drying or the like.To aluminum foil coil 10a wash with dried be in order to remove surface contaminants, then it to be heated.The melting temperature that the heating-up temperature of aluminum foil coil 10a preferably is higher than first polyester resin layer 4 that directly is attached to aluminum foil coil 10a.After the washing, also can carry out aforesaid surface treatment to aluminum foil coil 10a, purpose is in order to increase the interface binding power between the aluminum foil coil 10a and first polyester resin layer 4.
When aluminium foil was heated, double-layer polyester resin molding volume 20 was placed on another unreel equipment (not drawing in the drawings) and carries out unreel.
Aluminum foil coil 10b after the heat treatment and double-layer polyester resin molding volume 20 is put into together and is rolled bushing machine 30 and roll, when the aluminum foil coil 10b after the heat treatment and double-layer polyester resin molding volume 20 together when rolling bushing machine 30, first polyester resin layer 4 of double-layer polyester resin molding volume 20 is attached on the one side at least of aluminium foil 10b.Wherein first polyester resin layer 4 directly is attached to aluminum foil coil 10b, and second polyester resin layer 6 rolls on first polyester resin layer.In order to compensate aluminum foil coil 10b after the heat treatment delivering to the temperature that descends when rolling bushing machine 30, guarantee between aluminium foil and resin molding, to obtain stronger adhesive force, also can also be heated to suitable temperature with rolling bushing machine 30.
, be preferably in preset time and cool off to quench rapidly by rolling the resin molding aluminum foil coil 10c of bushing machine 30 just.Also can increase a heating process again, for example can further adopt post bake or cracking heating process in the quenching first being processed.By post bake process, the interface binding power between the aluminium foil 10b and first polyester resin layer 4, and the interface binding power between first polyester resin layer 4 and second polyester resin layer 6 all can further be strengthened.Process for cooling to resin molding aluminum foil coil 10c can adopt process for cooling or quenching technical at a slow speed, preferably adopts quenching technical.And water and air may be used in the process for cooling.
The temperature of aluminium foil 10b, roll the pressure and the surface temperature of volume machine 30, the post bake temperature and time that has adhered to the aluminium foil behind the resin molding, the temperature and time of cracking heating, and the temperature and time or the like of cooling, can decide by the speed of production line shown in the kind of corresponding resin molding and Fig. 2.
After the cooling, again the resin molding aluminium foil is carried out dried, if by quality testing, then be wound into and be two-sided polyester resin film aluminum foil coil 10d.By the double-layer polyester resin molding aluminum foil coil 10d that the above-mentioned course of processing is produced, can make the shell of electronic component by drawing and Technology for Heating Processing.
Wherein, can be attached to the wherein one side of aluminium foil 2, and produce above-mentioned resin molding aluminium foil with the mode that the improvement polyolefin resin film is attached to the another side of aluminium foil 2 by double-layer polyester resin bed 4 and 6.When making shell, draw in the mode of improvement polyolefin resin film as inner surface of outer cover with this resin molding aluminium foil.Described improvement polyolefin resin film has good insulation property and anticorrosive power to electrolyte, therefore can make between shell and the capacitor equipment to have good insulation performance.
Fig. 3 shows the double-layer polyester resin molding aluminium foil of making among Fig. 2 by drawing, to produce the flow process of capacitor case.At first, double-layer polyester resin molding aluminium foil is cut into a plurality of round paper tinsels 100.This circle paper tinsel 100 is loaded into multistage drawing device, and this multistage drawing device has a mould 200 and a stamping machine 210, draws in the mode of second polyester resin layer 6 as outer surface of outer cover then.
Except using circle paper tinsel 100, the multistage drawing device of also banded paper tinsel 110 can being packed into is drawn into shell.Then the shell that draws cutting and separating from the banded paper tinsel 110 is opened.
Among the present invention, the shape about the raw material paper tinsel of making shell does not have special importance.The shape of raw material paper tinsel does not have special significance, because circle, rectangle or other shapes all are identical for the drawing program.Therefore, for simplicity, following introduction is an example to justify paper tinsel 100.Shell for production has the big degree of depth generally uses multistage drawing device to draw.Multistage drawing device is a kind of equipment that a processing grade can be divided into several grades and the drawing degree of depth is deepened gradually, and if necessary, its diameter also can reduce gradually.Use this multistage drawing device to draw and add man-hour, circle paper tinsel 100 at first is drawn into the half cup shape shell 100a shown in Fig. 3 B gradually, presses and continues shown in Fig. 3 C and the 3D to draw, and can draw out the shell 100b and the 100c that deepen gradually and narrow down.Use cutter (not drawing in the drawings) that the top of shell 100c is cut away then, make the full cup-shaped shell 100d shown in Fig. 3 E at last.
Fig. 4 is with pack into the part sectioned view of a made chip capacitor after the full cup-shaped shell 100d that draws out by flow process shown in Fig. 3 A to 3E of capacitor equipment 300.As can be seen from Figure 4, pack into capacitor 300 among the full cup-shaped shell 100d after, also to suppress recessed edge and crimping processing, to form a recessed edge part 120 and bead portion 130 to the top of shell 100d.Then lid 310 is contained on the above-mentioned shaped structures, 320 of the electrode connecting lines of capacitor pass lid 310 and reach the outside.By such installation step, just made a chip capacitor.
But, this double-layer polyester resin molding heat that comprises first and second polyester resin layers of different fusing points is attached on the one side at least of aluminium foil, perhaps this double-layer polyester resin molding is attached to the one side of aluminium foil and improves the another side that polyolefin resin film is attached to aluminium foil, after making the resin molding aluminium foil, if draw, should be noted that following different problems may take place with said method.In the cup-shaped shell 100d that drawing is produced, the adhesive force between interface adhesive force between aluminium foil 2 and the polyester resin layer 4 and the polyester resin layer 4,6 may reduce, and resin molding is peeled off layering from aluminium foil situation may take place even.
The reason that produces these problems is as follows.After the plane paper tinsel drawn as circle paper tinsel or rectangle paper tinsel, its core was recessed, thereby becomes cup-like structure.In pulling process, the sidewall 122 of cup-shaped shell 100d is compared with the bottom 120 of cup-shaped shell 100d, and suffered drawing power is stronger.Especially come when enough big compared with bottom size when the height of side wall of outer shell, the drawing degree of aluminium foil can become higher.Aluminium foil 2 has different mechanical stresses and tensile property with polyester resin layer 4,6.If tree adipose membrane aluminium foil is drawn by the degree of depth, and then resin bed 4 and 6 may peel off from aluminium foil, and is particularly even more serious at sidewall 122 places, makes that finally the interface adhesive force between aluminium foil and the resin bed significantly weakens.If the degree of peeling off is serious, polyester resin layer 4,6 then can take place peel off the serious problems of layering from aluminium foil 2.
Fig. 5 shows the enlarged drawing of a sample under the partial cut from the sidewall 122 of the shell that is drawn into by above-mentioned double-layer polyester resin molding aluminium foil.In this shell, the surface of double-layer polyester resin molding aluminium foil has been printed on meticulous colored point, and these colored some regular distribution are in the surface of double-layer polyester resin molding.In this enlarged drawing, black color dots is the colored point of being printed, and vertical axis is represented the height of side wall of outer shell 122, and trunnion axis is represented the periphery of sidewall 122.Drawing first being processed, printing point is by printing in the mode of the adjacent arrangement of uniform interval in level and vertical direction.But because the drawing degree difference between each position, can find can become irregular arrangement because of drawing changes at the interval of vertical and horizontal direction between each point.As shown in Figure 5, before drawing, A point, B point and C point are positioned on the same horizontal line, and after the drawing, the B point is positioned at than A point and the much higher position of C point.Draw more part 400a, 400b ... and less part 410a, the 410b of drawing degree ..., can alternately repeat around sidewall 122, h2 is greater than interval h1 at interval.The fact from behind can find, and is less near the drawing degree that the sidewall 122 of bottom 120 is suffered, but can increase gradually along sidewall drawing degree upward.Like this, can demonstrate the drawing degree at sidewall 122, this drawing degree can alter a great deal according to the difference in sidewall 122 positions, and along sidewall upward to increasing gradually.For this reason, can produce a problem, i.e. interface adhesive force between the aluminium foil 2 of sidewall 122 and first polyester resin layer 4, and the interface adhesive force between first and second polyester resin layer 4,6 all can reduce greatly.The phenomenon that this interface adhesive force reduces also can occur between the improvement polyolefin resin film and shell aluminium foil that is attached to inner surface of outer cover.
In order to compensate and strengthen the interface adhesive force of aforementioned minimizing, the present invention also heat-treats the shell 100d that is drawn into.Heat treatment process is preferably in capacitor equipment 300 and packs into and carry out before the shell.
When heat treatment shell 100d, its heating-up temperature can be different according to the kind of first and second resin beds.Experiment is found, when one because of being drawn the shell that causes its interface adhesive force to reduce (just described later adhere to the shell that test is cited as " poor "), under 100~110 ℃ the temperature by 30 seconds of heat treatment or the longer time after, layering between its aluminium foil 2 and the double-layer polyester resin bed 4,6 breaks away from the surface and can restart to adhere to, and finally makes this shell be cited as " good ".And, find that also the improvement polyolefin resin film also can adhere to again, thereby guaranteed good attachment state between improvement polyolefin resin film and the aluminium foil.
Minimum temperature in the heat treatment process is preferably to select for use initially adheres to temperature, under this temperature, can return to the state of strong interface binding power between first polyester resin layer of peeling off from aluminium foil 24 and the aluminium foil 2.Be to be that the mode of unit is heat-treated shell with the part in the above-mentioned experiment.Different with this mode is, if put into a large amount of shells in the container and heat-treat simultaneously, all needs then minimum heating-up temperature and minimum heating time to promote and prolong.In addition,, then can show better adhesion property, adhere in the test in the description of back and will be cited as " very good " through heat treated shell if heat treated temperature is higher a little than described minimum temperature.
In heat treatment, the upper limit of heating-up temperature need be decided by required tack, thermal effectiveness and productivity ratio or the like factor.When a large amount of shells were heat-treated, heat treatment temperature was preferably lower than the initial fusion temperature of second polyester resin layer 6.This initial fusion temperature has shown the temperature when resin molding begins to melt.If heat treatment temperature is higher than the initial fusion temperature of second polyester resin layer 6, then second polyester resin layer 6 also can be melted.Like this, when a large amount of shells is put in the same container and heat-treats simultaneously, if shell is heated to above the initial fusion temperature of second polyester resin layer 6, then adjacent shell can because of outer surface be melted sticky together, thereby produce the product of inferior quality.In addition, even if the heating-up temperature of shell is not higher than the initial fusion temperature of second polyester resin layer 6, also can obtain desirable interface adhesive force fully.
Initially adhere to temperature and the initial fusion temperature of polyester resin film can be different because of factors such as the kind of mylar, molecular weight, and can with chart it be showed by experiment.For example, be respectively first and second polyester resin layers 4,6 of 207 ℃ and 255 ℃ for fusing point, its initial fusion temperature approximately is respectively 177 ℃ and 226 ℃, and in this case, the temperature of initially adhering to of first polyester resin layer 4 is approximately 100 ℃.In another example, be respectively first and second polyester resin layers 4,6 of 224 ℃ and 255 ℃ for fusing point, its initial fusion temperature is approximately 187 ℃ and 226 ℃ respectively, and in this case, the temperature of initially adhering to of first polyester resin layer 4 is approximately 110 ℃.Test factually as can be known, initially adhere to temperature approximately than low 70-80 ℃ of initial fusion temperature.For the improvement polyolefin resin film of selecting to be attached to inner surface of outer cover, its melting temperature is about 220 ℃ or lower, and with the kind of improvement polyolefin resin film some variation is arranged.Like this, because the fusing point of improvement polyolefin resin film is lower than the fusing point of second polyester resin layer, under above-mentioned heat-treat condition, the improvement polyolefin resin film can be adhered to once more effectively.
As mentioned above, when the shell that draws first mylar 4 initially adhere to temperature when heat-treating in the temperature range between the temperature to initially adhering to of second mylar 6, first polyester resin layer 4 once more close attachment to aluminium foil.In this case, because second polyester resin layer 6 heats initially adhering to below the temperature, so it can not melt.Finally can produce the effect that adhesive force increases by first polyester resin layer 4.
When the shell that draws was heat-treated in the said temperature scope, the adhesive force between aluminium foil 2, resin molding 4 and the resin molding 6 can be greatly improved.This result especially can effectively solve through regular meeting after some processing, after the processing of the recessed edge of extrusion that when capacitor equipment 300 is encased in shell, need carry out and crimping, taken place such as resin bed 4 and 6 problems that may peel off from aluminium foil 2.
In addition, this heat treatment can be boosted productivity greatly.Temperature when heat-treating is the initial fusion temperature that forms outermost second polyester resin layer 6, so outermost layer can not be melted.The phenomenon of mutual adhesion or damage even if contiguous shell contacts with each other during heat treatment, also can not take place in this expression.Like this, a large amount of shell 10c can be loaded in the heater and heat-treats simultaneously, and needn't leave the gap mutually, and promptly whether they contact with each other and can not exert an influence.So just significantly improved the specific productivity of heat treatment process.For example, heat treatment can be finished by following technology: a large amount of shells are put into a container, for example put into a netted pipe made from the thermal conductive resin material, heat in thermal chamber then; Or finish by another technology: a large amount of shells are placed on the conveyer line, and this conveyer line can heat shell when conveyer line passes through heater continuously or off and on then through as heaters such as electric furnaces.Certainly, even shell is to heat-treat with mutual separated state on a certain production line, the solution of the present invention is still effective aspect heat treatment cost, time and productivity ratio.
And, also have an important effect according to of the present invention in after-baking, promptly can increase the interface adhesive force after drawing between resin molding and the aluminium foil.Thereby improve being contained in the resistance of the electrolyte in the capacitor.When assembling a traditional electrolytic condenser, earlier the equipment that comprises anode strip and cathode sheets is soaked into fully at electrolyte, then put into shell again.Or earlier equipment is put in the shell, then use other device that electrolyte is poured into into.In this case, normally ethylene glycol or gamma-butyrolactone (C of electrolyte
4H
6O
2) and ethylene glycol mixtures.In above-mentioned assembling process, the phenomenon that solution leakage comes out can take place, or is bonded at the phenomenon on the assembly equipment (Japanese is commonly referred to " Koma ") that contacts with the external resin layer, when this state, shell can produce gross distortion.At this moment, if the resin bed that coats does not have resistance to electrolyte, then the outward appearance change can take place or break away from lamination in resin bed.
In general, polyester resin film commonly used all has good resistance to different chemical substances, especially electrolyte is had good resistance.This is because the degree of crystallinity that mylar is touched itself obtains increasing because of the mechanical stretching in the production process and thermal crystalline.Because the increase of its degree of crystallinity, this resin molding has good resistance to external action.
In order to make the interface degree of adhesion between aluminium foil and the double-layer polyester resin molding be enough to keep out common processed, be preferably in after the resin bed heating and being attached on the aluminium foil, under the condition of initially adhering to temperature or melting temperature of second resin bed that is higher than resin molding, shell carried out post bake.During post bake, second resin bed becomes unsetting state.The intrinsic characteristic of unsetting state mylar can significantly weaken, especially to gamma-butyrolactone (C
4H
6O
2) chemoresistance can significantly reduce.At this moment, the if tree adipose membrane is exposed to electrolyte in the capacitor assembling process, may cause the outward appearance of resin molding to change, and perhaps causes the resin molding layering that comes off.
But, for the shell that comprises the first and second different polyester resin layers of fusing point, if in the temperature range the initial fusion temperature of second polyester resin layer it is heat-treated in the temperature of initially adhering to from first polyester resin layer according to the solution of the present invention, atypic second polyester resin layer meeting quilt crystallization once more then becomes in the post bake process that resin molding is attached on the aluminium foil.Like this, second resin bed will have higher resistance to different chemical substances, especially electrolyte is had very outstanding resistance.
In order to check degree of crystallinity and crystallized temperature, the inventor is to first polyester resin layer, second polyester resin layer and include the double-side membrane that rolls first and second polyester resin layers together, has carried out differential scanning calorimetry (DSC) respectively and has analyzed (the model of the DSC equipment of use: PERKIN-ELMERDSC7).Fig. 7 is 207 ℃ and includes dimethyl terephthalate and the chart as a result of the dsc analysis gained that DMIP carries out as first polyester resin layer of its main repetitive fusing point.Fig. 8 is to be the chart as a result that 255 ℃ second polyester resin layer carries out the dsc analysis gained to fusing point.Wherein, thickness is 0.27 millimeter aluminium foil, and its surface is heated to 207~250 ℃ by electric induction heater.Then, with the aluminium foil of heating and the double-layer polyester resin molding of 15 micron thickness with first resin bed towards the mode of aluminium foil by rolling bushing machine, in the described double-layer polyester resin molding, comprise fusing point and be 207 ℃ and, and fusing point is 255 ℃ the second conjugated polyester resin layer with dimethyl terephthalate and DMIP the first conjugated polyester resin layer as its main repetitive.Like this, resin molding is attached on the aluminium foil.Then, in 225~270 ℃ double-layer polyester resin molding aluminium foil is heated again, and then quench.Fig. 9 carries out the chart as a result of dsc analysis gained to being attached to double-layer polyester resin molding on the aluminium foil.
As shown in Figure 9, be attached to crystallization temperature that the double-layer polyester resin molding of aluminium foil demonstrates between 128 ℃ (FCTA temprature) are to 197 ℃, the crystallization peak temperature is 158 ℃.This crystallization temperature is consistent with the effect that the interface adhesive force between aluminium foil and the resin molding significantly increases, and the effect that its median surface adhesive force significantly increases is by shell being heat-treated the back in the temperature range the initial fusion temperature of second resin bed and produce in the temperature of initially adhering to from first resin bed.What it is contemplated that is, first resin bed of adjacent aluminium foil can since the heat treatment in the said temperature scope by crystallization, thereby cause the interface adhesive force between first resin bed and the aluminium foil to weaken.But, as shown in Figure 7,, it is difficult to by the DMIP of crystallization because containing, and first polyester resin layer will be difficult to by thermal crystalline.In addition, because first polyester resin layer is to be higher than under its condition of initially adhering to temperature by heat treated, so the situation that causes interface adhesive force to descend by the crystallization of first polyester resin layer just can not take place.
For the present invention and prior art are compared, fusing point is higher than 240 ℃ polyester resin film and is attached on the aluminium foil of the melting temperature that is heated to above this resin molding by heat, resin molding aluminium foil to gained draws then, make the resin molding that adheres to outer surface as structure, then, the structure that is drawn into reduce to its weight of heating back from the initial fusion temperature of resin molding 10% or temperature still less the time temperature range in heat-treat, make the shell of electronic component at last.Measure the chemoresistance of this shell then, and measurement result is compared with the result of gained of the present invention aforementioned electrolyte.Comparative result is that different with the present invention is that according to the shell that prior art is produced, in the course of processing of shell that the capacitor that is marked with electrolyte is packed into, quite most of resin molding has produced the layering that comes off.This may be because the shell that draws be in the condition of initially adhering to temperature that is higher than resin molding by heat treated, and the major part of resin molding has become unsetting state under this temperature.By above-mentioned contrast as can be known, the present invention is the settling mode of an efficient and cost-effective, can increase considerably the interface adhesive force between aluminium foil and the resin molding attached to it, and improves the needed chemoresistance characteristic of capacitor case.
To describe in further detail the present invention by example and comparison example below.But what should keep firmly in mind is that the present invention is not limited to these real examples.
Example 1
Thickness is 0.27 millimeter aluminium foil, and its surface is heated to 195~250 ℃ with electric induction heater.Then, through the aluminium foil of heating and the double-layer polyester resin molding of 15 micron thickness with first resin bed towards the mode of aluminium foil by rolling bushing machine, thereby resin molding attached on the aluminium foil, is comprised fusing point and is 195 ℃ and be first conjugated polyester resin layer of main repetitive and the second conjugated polyester resin layer that fusing point is 255 ℃ with dimethyl terephthalate and DMIP in the double-layer polyester resin molding wherein.Then under 225~260 ℃ of conditions, made double-layer polyester resin molding aluminium foil is heated, quench again afterwards.Then, the resin molding aluminium foil is cut into round paper tinsel, and in the mode of resin molding as outer surface of outer cover, the circle paper tinsel is drawn processing, making the shell of electrolytic condenser, the diameter of each shell is 4 millimeters, highly is 5.3 millimeters.100 electrolytic condenser shells are put into an aluminium vessel with holes, and in electric furnace with 120 ℃ of heat treatments 1 minute.After the heat treatment, do not have inter-adhesive between the outer surface of adjacent shells (second polyester resin layer).Then heat treated electrolytic condenser shell is carried out visual examination, and projects such as its adhesive force, machinability, solvent resistance, insulating properties, thermal resistance are detected.
Example 2
Thickness is 0.27 millimeter aluminium foil, and its surface is heated to 205~250 ℃ with induction heater.Then, aluminium foil through heating, the double-layer polyester resin molding of 15 micron thickness, and fusing point is 190 ℃ an improvement polyolefin resin film, with first resin bed towards the wherein one side of aluminium foil and the improved resin face to the mode of the another side of aluminium foil, together by rolling bushing machine, thereby polyester resin film and improvement polyester resin film all are attached on the aluminium foil, comprise fusing point in the double-layer polyester resin molding wherein and be 205 ℃ and be the first conjugated polyester resin layer of main repetitive with dimethyl terephthalate and DMIP, and fusing point is 258 ℃ the second conjugated polyester resin layer.Then, under 225~260 ℃ of conditions, made double-layer polyester resin molding aluminium foil is heated, quench again afterwards.Then the resin molding aluminium foil is cut into round paper tinsel, and in the mode of resin molding as outer surface of outer cover, the circle paper tinsel is drawn processing, making the shell of electrolytic condenser, the diameter of each shell is 5 millimeters, highly is 5.3 millimeters.Then 100 electrolytic condenser shells are put into an aluminium vessel with holes, and in electric furnace with 150 ℃ of heat treatments 2 minutes.After the heat treatment, do not have inter-adhesive between the outer surface of adjacent shells (second polyester resin layer).Then heat treated electrolytic condenser shell is carried out visual examination, and projects such as its adhesive force, machinability, solvent resistance, insulating properties, thermal resistance are detected.
Example 3
Thickness is 0.3 millimeter aluminium foil, and its surface is heated to 225~250 ℃ with induction heater.Then, through the aluminium foil of heating and the double-layer polyester resin molding of 25 micron thickness with first resin bed towards the mode of aluminium foil by rolling bushing machine, thereby attached on the aluminium foil, double-layer polyester resin molding wherein comprises fusing point to be 225 ℃ and to be first conjugated polyester resin layer of main repetitive and the second conjugated polyester resin layer that fusing point is 260 ℃ with dimethyl terephthalate and DMIP with resin molding.Then under 225~270 ℃ of conditions, double-layer polyester resin molding aluminium foil is heated, quench again afterwards.Then the resin molding aluminium foil is cut into round paper tinsel, and in the mode of resin molding as outer surface of outer cover, the circle paper tinsel is drawn processing, making the shell of electrolytic condenser, the diameter of each shell is 8 millimeters, highly is 10 millimeters.Then 100 electrolytic condenser shells are put into an aluminium vessel with holes, and in electric furnace with 205 ℃ of heat treatments 30 minutes.After the heat treatment, between the outer surface of adjacent shells (second polyester resin layer) some insignificant adhesions are arranged, but the not change of its outward appearance, and do not find bad shell.Then heat treated electrolytic condenser shell is carried out visual examination, and projects such as its adhesive force, machinability, solvent resistance, insulating properties, thermal resistance are detected.
Example 4
Thickness is 0.27 millimeter aluminium foil, and its surface is heated to 185~250 ℃ with induction heater.Then, through the aluminium foil of heating and the double-layer polyester resin molding of 20 micron thickness with first resin bed towards the mode of aluminium foil by rolling bushing machine, thereby attached on the aluminium foil, double-layer polyester resin molding wherein comprises fusing point to be 185 ℃ and to be first conjugated polyester resin layer of main repetitive and the second conjugated polyester resin layer that fusing point is higher than 260 ℃ with dimethyl terephthalate and DMIP with resin molding.Then, under 225~260 ℃ of conditions, double-layer polyester resin molding aluminium foil is heated, quench again afterwards.Then, the resin molding aluminium foil is cut into round paper tinsel, and in the mode of resin molding as outer surface of outer cover, the circle paper tinsel is drawn processing, make the shell of electrolytic condenser, the diameter of each shell is 6 millimeters, highly is 5.9 millimeters.It is 350 millimeters that 50,000 electrolytic condenser shells are put into a diameter, highly is in 550 millimeters the rustless steel container with holes, in electric furnace with 15 ℃ of heat treatments 40 minutes.After the heat treatment, do not have inter-adhesive between the outer surface of adjacent shells (second polyester resin layer).Then heat treated electrolytic condenser shell is carried out visual examination, and projects such as its adhesive force, machinability, solvent resistance, insulating properties, thermal resistance are detected.
Example 5
Thickness is 0.3 millimeter aluminium foil, and its face surface is heated to 230~250 ℃ with induction heater.Then, through the aluminium foil of heating and the double-layer polyester resin molding of 15 micron thickness with first resin bed towards the mode of aluminium foil by rolling bushing machine, thereby attached on the aluminium foil, double-layer polyester resin molding wherein comprises fusing point to be 230 ℃ and to be first conjugated polyester resin layer of main repetitive and the second conjugated polyester resin layer that fusing point is higher than 260 ℃ with dimethyl terephthalate and DMIP with resin molding.Then, under 225~260 ℃ of conditions, double-layer polyester resin molding aluminium foil is heated, quench again afterwards.Then, the resin molding aluminium foil is cut into round paper tinsel, and in the mode of resin molding as outer surface of outer cover, the circle paper tinsel is drawn processing, make the shell of electrolytic condenser, the diameter of each shell is 8 millimeters, highly is 10 millimeters.It is that 350 millimeters height are 550 millimeters rustless steel container with holes that 50,000 electrolytic condenser shells are put into a diameter, in electric furnace with 215 ℃ of heat treatments 30 minutes.After the heat treatment, between the outer surface of adjacent shells (second polyester resin layer) some insignificant adhesions are arranged, but the not change of its outward appearance, and do not find bad shell.Then heat treated electrolytic condenser shell is carried out visual examination, and projects such as its adhesive force, machinability, solvent resistance, insulating properties, thermal resistance are detected.
Example 6
Thickness is 0.27 millimeter aluminium foil, and its surface is heated to 205~250 ℃ with induction heater.Then, through the aluminium foil of heating and the double-layer polyester resin molding of 15 micron thickness with first resin bed towards the mode of aluminium foil by rolling bushing machine, thereby attached on the aluminium foil, double-layer polyester resin molding wherein comprises fusing point to be 250 ℃ and to be first conjugated polyester resin layer of main repetitive and the second conjugated polyester resin layer that fusing point is higher than 260 ℃ with dimethyl terephthalate and DMIP with resin molding.Then, under 225~260 ℃ of conditions, double-layer polyester resin molding aluminium foil is heated, quench again afterwards.Then, the resin molding aluminium foil is cut into round paper tinsel, and in the mode of resin molding as outer surface of outer cover, the circle paper tinsel is drawn processing, make the shell of electrolytic condenser, the diameter of each shell is 6 millimeters, highly is 5.9 millimeters.100,000 electrolytic condenser shells are put into 10 rustless steel containers with holes, by a continuous electric furnace shell is heat-treated with the transfer rate of 0.1 millimeter per minute.This length that is used for heat treated continuous electric furnace is 3 meters, and it is 180 ℃ that its inlet temperature is maintained 120 ℃, central temperature, and entrance and exit is open, and continuous transfer system is installed so that heat treatment operation can carry out continuously.After the heat treatment, between the outer surface of adjacent shells (second polyester resin layer) some insignificant adhesions are arranged, but the not change of its outward appearance, and do not find bad shell.Then heat treated electrolytic condenser shell is carried out visual examination, and projects such as its adhesive force, machinability, solvent resistance, insulating properties, thermal resistance are detected.
Comparison example 1
Thickness is 0.27 millimeter aluminium foil, and its surface is heated to 195~250 ℃ with induction heater.Then, through the aluminium foil of heating and the double-layer polyester resin molding of 15 micron thickness with first resin bed towards the mode of aluminium foil by rolling bushing machine, thereby with resin molding attached on the aluminium foil.Double-layer polyester resin molding wherein comprises fusing point to be 185 ℃ and to be first conjugated polyester resin layer of main repetitive and the second conjugated polyester resin layer that fusing point is 260 ℃ with dimethyl terephthalate and DMIP.Then, under 225~260 ℃ of conditions, double-layer polyester resin molding aluminium foil is heated, quench again afterwards.Then, with the mode of resin molding as outer surface of outer cover, the circle paper tinsel is drawn processing, make the shell of electrolytic condenser, the diameter of each shell is 4 millimeters, highly is 5.3 millimeters.Surface, adhesion, solvent resistance, machinability, insulating properties to the heat treated shell of electrolytic condenser detect and thermo-resistance measurement.
Comparison example 2
Thickness is 0.27 millimeter aluminium foil, and its surface is heated to 250~270 ℃ with induction heater.Then, through the aluminium foil of heating with 20 micron thickness and fusing point be 245 ℃ conjugated polyester resin film by rolling bushing machine, thereby with polyester resin film attached on the aluminium foil.Then, in the mode of resin molding as outer surface of outer cover, described single-layer resin film aluminium foil is drawn processing, make the shell of electrolytic condenser, the diameter of each shell is 4 millimeters, highly is 5.3 millimeters.100 shells that make are as stated above put into an aluminium vessel with holes, in electric furnace with 120 ℃ of heat treatments 1 minute.After the heat treatment, there is not adhesion between the outer surface of adjacent shells (second polyester resin layer).Then heat treated electrolytic condenser shell is carried out visual examination, and projects such as its adhesive force, machinability, solvent resistance, insulating properties, thermal resistance are detected.
Comparison example 3
Thickness is 0.3 millimeter aluminium foil, and its surface is heated to 250~270 ℃ with induction heater.Then, through the aluminium foil of heating with 20 micron thickness and fusing point be 245 ℃ conjugated polyester resin film by rolling bushing machine, thereby resin molding is attached on the aluminium foil.Then, in the mode of resin molding as outer surface of outer cover, single-layer resin film aluminium foil is drawn processing, make the shell of electrolytic condenser, the diameter of each shell is 8 millimeters, highly is 10 millimeters.100 shells that make are as stated above put into an aluminium vessel with holes, in electric furnace with 150 ℃ of heat treatments 2 minutes.After the heat treatment, there is not adhesion between the outer surface of adjacent shells.Then heat treated electrolytic condenser shell is carried out visual examination, and projects such as its adhesive force, machinability, solvent resistance, insulating properties, thermal resistance are detected.
Comparison example 4
Thickness is 0.27 millimeter aluminium foil, and its surface is heated to 260~280 ℃ with induction heater.Then, through the aluminium foil of heating with 20 micron thickness and fusing point be 250 ℃ conjugated polyester resin film by rolling bushing machine, thereby with resin molding attached on the aluminium foil.Then, in the mode of resin molding as outer surface of outer cover, single-layer resin film aluminium foil is drawn processing, make the shell of electrolytic condenser, the diameter of each shell is 5 millimeters, highly is 5.3 millimeters.100 shells that make are as stated above put into an aluminium vessel with holes, in electric furnace with 240 ℃ of heat treatments 1 minute.After the heat treatment, serious adhesion when inter-adhesive shell is separated, is observed the impaired situation of surface resin film between the outer surface of adjacent shells.Then heat treated electrolytic condenser shell is carried out visual examination, and projects such as its adhesive force, machinability, solvent resistance, insulating properties, thermal resistance are detected.
Comparison example 5
Thickness is 0.3 millimeter aluminium foil, and its surface is heated to 250~280 ℃ with induction heater.Then, through the aluminium foil of heating with 20 micron thickness and fusing point be 255 ℃ conjugated polyester resin film by rolling bushing machine, thereby resin molding is attached on the aluminium foil.Then, press the mode of resin molding as outer surface of outer cover, single-layer resin film aluminium foil is drawn processing, make the shell of electrolytic condenser, the diameter of each shell is 8 millimeters, highly is 10 millimeters.The shell of 50,000 electrolytic condensers that make is as stated above put into 350 millimeters of diameters, 550 millimeters rustless steel container with holes of height, in electric furnace with 240 ℃ of heat treatments 30 minutes.After the heat treatment, serious adhesion when inter-adhesive shell is separated, is observed the impaired situation of surface resin film between the outer surface of adjacent shells.Then heat treated electrolytic condenser shell is carried out visual examination, and projects such as its adhesive force, machinability, solvent resistance, insulating properties, thermal resistance are detected.
Comparison example 6
Thickness is 0.27 millimeter aluminium foil, and its surface is heated to 220~260 ℃ with induction heater.Then, through the aluminium foil of heating with 20 micron thickness and fusing point be 245 ℃ conjugated polyester resin film by rolling bushing machine, be on the aluminium foil thereby resin molding is attached to.Then, press the mode of resin molding as outer surface of outer cover, single-layer resin film aluminium foil is drawn processing, make the shell of electrolytic condenser, the diameter of each shell is 6 millimeters, highly is 5.9 millimeters.The shell of 50,000 electrolytic condensers that make is as stated above put into 350 millimeters of diameters, 550 millimeters rustless steel container with holes of height, in electric furnace with 230 ℃ of heat treatments 30 minutes.After the heat treatment, serious adhesion when inter-adhesive shell is separated, is observed the impaired situation of surface resin film between the outer surface of adjacent shells.Then heat treated electrolytic condenser shell is carried out visual examination, and projects such as its adhesive force, machinability, solvent resistance, insulating properties, thermal resistance are detected.
The electrolytic condenser shell that makes in above-mentioned example and the comparison example is tested, and its result is as shown in table 1.
<visual examination 〉
Observe the situation in each shell cross section.And whether the resin molding of checking shell damages.
<adhere to test 〉
The sidewall surfaces of each shell is peeled off test with the 3M adhesive tape after forming 50 indentations by 1 millimeter interval.
<workability test 〉
After making the aluminium electrolyte capacitor with each shell, detect the processing conditions of bead portion and recessed edge part.
<solvent resistance test 〉
Respectively shell is immersed in methyl alcohol and the isopropyl alcohol, detect the cosmetic variation and the solubility of resin molding, and the resistance before and after relatively immersing.
<electrolyte soaks into test 1 〉
Contain gamma-butyrolactone (C with what each shell immersed room temperature condition
4H
6O
2) and the electrolyte of ethylene glycol in after 30 minutes, observe its cosmetic variation.After finishing crimping processing required when capacitor packed into shell, check whether resin molding breaks away from the situation of layering.
<electrolyte soaks into test 2 〉
Each shell immersion is contained gamma-butyrolactone (C
4H
6O
2) and 80 electrolyte of ethylene glycol in after 30 minutes, observe its cosmetic variation.After finishing crimping processing required when capacitor packed into shell, check whether resin molding breaks away from the situation of layering.
<insulating properties test 〉
Each shell is immersed the copper sulphate (CuSO that contains every liter of 5 gram
4-5H
2O) after 3 minutes, whether the outer surface of observing shell has the copper deposition and in the solution of hydrochloric acid of every liter of 5 gram.If copper deposition is arranged, can infer that then resin molding has and break, break away from layering or damage phenomenon.
<thermo-resistance measurement 1 〉
Each shell is placed in the heat dish that is heated to 250 ℃, and the top of shell contacts with the heat dish.And add 100 kilograms 30 seconds of heavy burden to shell, check that then the resin molding of shell upper breaks away from the layering situation.
<thermal resistance test 2 〉
Shell is put into 30 seconds in the electric furnace that is heated to 300 ℃.Whether the resin molding of checking outer surface of outer cover then has contraction, breaks away from situations such as layering, variable color.
Above-mentioned test result is provided by table 1.
<table 1〉test result
Project | Outward appearance | Adhere to | Machinability | Solvent resistance | Soak into electrolyte 1 | Soak into electrolyte 2 | Insulating properties | Resistive properties 1 | Resistive properties 2 |
Example 1 | ??A | ??A | ????A | ????A | ????A | ????A | ????A | ????A | ????A |
Example 2 | ??A | ??A | ????A | ????A | ????A | ????A | ????A | ????A | ????A |
Example 3 | ??A | ??A | ????A | ????A | ????A | ????A | ????A | ????A | ????A |
Example 4 | ??A | ??A | ????A | ????A | ????A | ????A | ????A | ????A | ????A |
Example 5 | ??A | ??A | ????A | ????A | ????A | ????A | ????A | ????A | ????A |
Example 6 | ??A | ??A | ????A | ????A | ????A | ????A | ????A | ????A | ????A |
Case of comparative examples 1 | ??A | ??B | ????B | ????A | ????X | ????X | ????B | ????A | ????A |
Case of comparative examples 2 |
??A |
??X |
????X |
????A |
????A |
????A |
????B |
????C |
????C |
Case of comparative examples 3 |
??A |
??C |
????X |
????A |
????A |
????A |
????B |
????C |
????C |
Case of comparative examples 4 |
??X |
??A |
????A |
????A |
????B |
????C |
????C |
????B |
????B |
Case of comparative examples 5 |
??X |
??A |
????A |
????A |
????B |
????C |
????C |
????B |
????B |
Case of comparative examples 6 |
??X |
??A |
????A |
????A |
????A |
????A |
????C |
????C |
????X |
Annotate: A=is excellent, and B=is good, and among the C=, X=is poor
From the test result of table 1 as can be seen, example of the present invention all demonstrates good characteristic in all evaluation items.
Whether the interface adhesive force between aluminium foil and the resin molding there is the effect of improvement for detecting heat treatment of the present invention,, interface adhesive force is carried out following test according to variation of temperature.
(1) formation of test sample book
Thickness is 0.3 millimeter aluminium foil 500, and its surface is heated to 195~250 ℃ with induction heater.Then, through the aluminium foil of heating and the double-layer polyester resin molding 510 of 15 micron thickness with first resin bed towards the mode of aluminium foil by rolling bushing machine, thereby resin molding is attached on the aluminium foil.Double-layer polyester resin molding wherein comprises fusing point to be 195 ℃ and to be first conjugated polyester resin layer of main repetitive and the second conjugated polyester resin layer that fusing point is 255 ℃ with dimethyl terephthalate and DMIP.Then under 225~255 ℃ of conditions, double-layer polyester resin molding aluminium foil is heated, quench again afterwards.
Is thickness that 0.285 millimeter resin molding aluminium foil cuts into piece, every is 100 millimeters * 150 millimeters sizes, with volume pressure mode the aluminium foil piece is made different pieces then, its thickness is respectively 0.25 millimeter (thickness reduces 18%), 0.22 millimeter (thickness reduces 23%), 0.20 millimeter (thickness reduces 30%), 0.16 millimeter (thickness reduces 44%), 0.12 millimeter (thickness reduces 58%), 0.10 millimeter (thickness reduces 65%).The size that can obtain test sample book from the single resin molding aluminium foil that rolls is 25 millimeters * 100 millimeters.
(2) method of testing
As shown in Figure 6, protection is attached to the surface of the PET film 510 of each test sample book with 3M adhesive tape 520.Cut the another side of aluminium foil with cutter, and aluminium foil is bent, draw the test sample book of peeling off of one 180 degree.Maximum load when the resin molding that uses the tension force detector to detect above-mentioned sample peels off.And calculate its T type peel force.Test result such as following table 2 are listed.
(3) test result
<table 2〉corresponding to the variation of the interface adhesive force of heat treatment temperature (kilogram/25 millimeter)
| Non-heat treatment | ????90 | ????120 | ????150 | ????180 | ????210 | ????260 |
0.25 millimeter | ??2.56 | ????1.88 | ????I.M. | ????I.M. | ????I.M. | ????I.M. | ????I.M. |
(thickness reduces 18%) | | | | | | | |
0.22 millimeter (thickness reduces 23%) | ????2.44 | ????1.84 | ????I.M. | ????I.M. | ????I.M. | ????I.M. | ????I.M. |
0.20 millimeter (thickness reduces 30%) | ????2.18 | ????1.56 | ????I.M. | ????I.M. | ????I.M. | ????I.M. | ????I.M. |
0.16 millimeter (thickness reduces 44%) | ????2.02 | ????1.40 | ????2.96 | ????I.M. | ????I.M. | ????I.M. | ????I.M. |
0.12 millimeter (thickness reduces 58%) | ????1.20 | ????1.22 | ????2.70 | ????I.M. | ????I.M. | ????I.M. | ????I.M. |
0.10 millimeter (thickness reduces 65%) | ????0.65 | ????0.74 | ????2.50 | ????I.M. | ????I.M. | ????I.M. | ????I.M. |
Annotate: I.M.=can not measure
Peel off when test, sample must be just like peeling off part shown in the D part among Fig. 6.But the sample that is expressed as " can not measure " in the table 2 had all broken before sample is stripped from PET film 510.Unless this proof resin molding breaks, even if otherwise draw the course of processing through the degree of depth, resin molding can not strip down from aluminium foil yet.PET film 510 rupture strengths that record are 4.6-6.8 kgf/25 millimeter (maximum heavy burdens), and relevant with volume pressure ratio rate with heat treatment temperature.Can find that like this in the test sample book that is expressed as " can not measure ", its resin molding peels off intensity and is higher than 4.6 kgfs/25 millimeter.
(4) conclusion
Can find that from test result the peel force of resin molding descends rapidly corresponding to the rising meeting of volume pressure ratio rate.Show that the degree of depth draws the resin molding that processing adheres to and may be stripped from the process of the process neutralizing capacitor assembling of making capacitor case.In table with test results 1, comparison example 1 does not show good tack, in capacitor case manufacturing process, draw the bigger side wall of outer shell of the degree of depth and in this process, draw the less outer casing bottom of the degree of depth and compare, both thickness differences are about 30%, and the capacitor case of drawing is in the processing of carrying out also carrying out crimping in the capacitor fabrication process and extruding recessed edge subsequently.Consider that these facts can find, in order to show good interface adhesive force between shell and the aluminium foil in the production process of whole capacitor device, even through after the strict processing, interface adhesive force all must be at least 2.2 kgfs/25 millimeter.
From above-mentioned detailed description of the present invention as can be known, in the test sample book after heat-treating in the temperature range between the initial fusion temperature of initially adhering to the temperature and second resin bed of first resin bed, except some thickness has seriously reduced 44% or more and the test sample book of heat-treating under 120 ℃, can not produce and strip off phenomenon.This peel strength that shows resin molding is bigger than rupture strength, is not stripped off yet after splitting so that resin molding pulls open.Correspondingly, if the heat treatment process of introducing among enforcement the present invention, even drawn in producing the capacitor case process, and consider that the degree of depth that 30% capacitor case can be subjected to draws or distortion in making the process of capacitor, resin molding can not strip off yet.
According to the test result of stripping off intensity that test sample book of the present invention drew, and, do not have too big difference according between the test result that test sample book drew that in certain temperature range, melts fully.This certain temperature range is meant in the prior art of describing in front, from the initial fusing of resin molding and its weight of heating back reduce 10% or still less temperature between temperature range, or from the initial fusion temperature of resin molding to the temperature range the decomposition temperature of resin molding.
Simultaneously can find that the peel strength of heat treated test sample book can be lower than not heat treated test sample book slightly under 90 ℃ of conditions.The temperature of initially adhering to that shows first resin bed is higher than 90 ℃, be lower than initially the adhering under the temperature conditions after Overheating Treatment of first resin bed, because of the resin molding that draws and the volume pressure causes its adhesive force to reduce to some extent can further be caused the tack of resin molding to descend a little to some extent by slight crystallization.
According to foregoing description of the present invention as can be known, thereby the reduction that in the heat treatment process of prior art, takes place such as extra heat treatment cost, productivity ratio, corresponding to the needs of different shell sizes independently Equipment for Heating Processing need extra problems such as equipment cost, the present invention all can be solved.And, the present invention provides a kind of shell with good thermal resistance for electronic component, even especially after the degree of depth draws extraordinary interface adhesive force is arranged also between its aluminium foil and the resin molding attached to it, the present invention also can provide a kind of method of producing this shell.
Because wrapped the double-layer polyester resin molding on its aluminium foil, the electronics enclosure 100d that is produced by the present invention has the good insulation performance performance.And, has good thermal resistance as outer field second resin bed 6 of shell, when a capacitor that is contained in this shell is fixed on the substrate, even such as welding with do not have under the contour temperature of lead welding under the processing conditions, polyester resin layer 4 and 6 can variable color and damage yet, and can show good characteristic under normal serviceability temperature.And, can be strengthened greatly again owing to drawing the adhesive force that reduces between aluminium foil 2 and the resin film layer 4,6, so even in the capacitor assembling course of processing, shell also can show good assembling performance, can not produce such as resin bed and shear or layering defective such as come off.Again because the heat treatment temperature of shell is higher than initially adhering to temperature but being lower than the initial fusion temperature of second polyester resin layer 6 of first polyester resin layer 4, second polyester resin layer 6 can not melt in heat treatment process, can be not inter-adhesive between the outer surface of outer cover thereby make.Like this, just a large amount of shells can be heat-treated simultaneously, to boost productivity.In addition, shell is to heat-treat in the crystallization range of resin molding, polyester resin film can crystallization under this condition, thus increased its to the different chemical material especially to the resistance of electrolyte.
Though the present invention has described preferred embodiment for the purpose that illustrates, be understandable that those skilled in the art can carry out various modifications, increase or replacement under the prerequisite of the scope and spirit that do not break away from claims.