DE2003982A1 - Copper-clad plastic sheet and method for producing the same - Google Patents

Description

The Cincinnati Milling Machine Co., Cincinnati »Ohio / USA

ferked ashes plastic

Manufacturing the same

The invention relates to copper-clad plastic panels, as used in the production of clay printed circuits, and in particular to panels of the type mentioned, in which the plastic plate is reinforced with a had made of an endless glass fiber strand and in which the copper foil has an improved surface smoothness .

In the manufacture of printed circuits, a copper- coated plastic plate is usually assumed, which essentially consists of a pressed, reinforced plastic plate on which a copper foil is attached on one or both sides.

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can be attached to the fabric by a layer of adhesive. the However, desired adhesion of the Polie to the plastic is preferably achieved in that the plate is placed directly on the Polie is formed "Such a process is described in US Pat. No. 3,149,021"

In order for them to be useful for printed circuits, must the copper-clad plates meet a wide variety of electrical and physical conditions. For example, during the manufacture of printed circuit boards, the boards are immersed in a molten solder bath. No damage may occur here, such as warping or other physical deformation or a Separation of the film from the plastic. The plates must also have the necessary physical strength so that they can be assembled into circuits and used under a wide variety of conditions “After all, they have to can also be bent to a certain extent, whereby neither the printed circuit conductors nor the substrate must break »It is also important that the film has a uniform thickness and a high surface quality, and especially when the printed circuit board has many tightly packed fine conductors.

The bending of the panels can occur under a wide variety of conditions. For example, during the manufacture ^ development of printed circuits and especially with «Bin * immerse in the solder bath an inclination so that the plates move throw. In such a case the plate can be bent in a certain way to compensate for the throw. At some stage in the manufacture of printed circuit boards, it is common to drill holes in the board. When pulling out the drills, they can get stuck and bend cause of the plate. Finally, a malfunctioning automatic component insertion machine can die

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Coil "Venn bending in a direction takes place, that the copper foil is located on the convex side of the plate, then the conductors can break the printed circuit or tear _o

It has been found that panels with improved flexural properties can be obtained when used as reinforcement a hat made from a continuous glass fiber strand used in the plastic. Such hats made from continuous Strands can be made by laying a series of endless strands in a zigzag on a moving belt Laying fiberglass strands, each of these strands is composed of a considerable number of extruded threads β. The strands are fed to the belt at a linear speed which is considerably greater than that Speed of movement of the belt. Furthermore, the fibers are given a transverse to the belt reciprocating motion when they are fed to the belt, so that on the Tape a layer of continuous fibers is deposited in an overlapping and intertwined manner «, Das Gewioht der It is determined by the speed at which the strands are formed, by the number and spacing of the strands and duroh the Movement speed of the band determines

If the mat has been made on dl · ·· Veiee, then is applied "in binding resin" to the mat, tm you a " Provide sufficient cohesion so that they are transported and be handled. Blndehars can hit the hat In powder form or in the form of a solution or suspension of the Resin can be sprayed onto the mat. Hach the anger of the binder resin, the mat is heated to melt and cure the resin and around the fibers of the mat together connect to. Fig. 1 of the accompanying drawings shows one of the continuous strands with ears had bound.

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Although panels reinforced with such panels made from continuous strands have considerably improved flexural strength, it has been found that when panels of the type heretofore proposed for this application are used, the panels obtained have the material part that during their Production of the resin-bonded mat and in particular the fibers lying in the vicinity of the foil slightly deform the copper foil Fig. 2 _{: of} the accompanying drawings shows a copper-clad plate, which consists of an upper foil 10, a lower foil 12 and a central reinforced plastic plate 14, to which the two foils are bound consists "The glass fibers of the hat are reproduced on the surface of the foil, as can be seen in FIG. 2". These irregularities in the surface of the film adversely affect the precision of printed circuit boards made from it and are particularly undesirable when the board is to be used in the production of printed circuit boards which contain fine conductors in close proximity «

The invention is accordingly based on the object of creating a copper-clad plate for printed circuits, in which the plastic plate is reinforced with a mat made of a continuous strand of aiaefiber and the exposed Surface of the film has an improved smoothness. Am· It is another task of the charge. a process for the production of a copper & sheer plate to be used with a mat made of a continuous glass fiber strand is reinforced and which has a button roll surface with improved smoothness.

According to the invention, it was found that the deformation of the Copper foil can be reduced considerably during the manufacturing process discussed above by using a resin-bonded mat consisting of endless fiberglass strands, toel

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That the binder resin is soluble in the liquid polymerizable composition used to make the plastic substrate of the panel. If a soluble binder is used on the glass mat, then the binder will either be dissolved in the monomers of the polymerizable composition or softened to a sufficient extent that a movement of the fibers of the mat relative to one another is made possible and thus largely or practically completely the deformation of the copper foil by the fibers during the manufacture of the plastic sheet can be avoided. In any case, whatever the mechanism, it has been found that when a binder resin β soluble in the polymerizable composition is used in the manufacture of a plastic sheet, a considerable improvement in the surface smoothness of the copper foil is achieved Measuring instruments for determining the surface shape are shown. The method of the present invention can produce panels with a surface smoothness of 0.05 mm or less as measured by a standard surface shape measuring device.

The kind of the soluble binder used for binding the strands of the GKLasmatte may be different and depends on the door of the Ha used polyaerisierbaren liarssuaammeneetnaig afc. Sin · kind of polymeric composition that is widely used in the manufacture of plastic sheet !! used for printed circuits ▼ consists of a mixture of an unsaturated polyester and methyl methacrylate, either with or without added Bpozyd. If such a polymerizable composition is used, then the preferred soluble binder for the Olas mat consists of an unsaturated polyester "which is solid at room temperature and which can be the" polyester which is also present in the polymerizable composition ". Such polyesters can

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be prepared by mixing glycols, such as Z ₀ B. ethylene glycol and the various isomers of propylene, butylene, pentylene and hexylene glycol, with unsaturated acids, such as, for example, maleic, fumaric and itaconic acid and also in a manner known per se the anhydrides thereof, condensed. Acid and glycol mixtures can be used in a manner known per se for the production of such polyesters. Other useful polyesters are shown in U.S. Patents 2,634,251 and 2,662,070.

Other types of soluble binders, which can be used in the present process, Z is ₀ for example, the phenolic and epoxy resins. In general, any polymer or resin which can temporarily bind the glass fibers of the mat and which is soluble in the polymerizable composition used in making the panel can be used. It is advantageous if the soluble binder is chemically similar to one or more of the polymerizable components of the molding compound and is therefore copolymerizable in order to ensure that the dissolved binder does not adversely affect the desired properties of the finished board. The use of an unsaturated polyester binder on the glass mat and a polymerizable composition containing a substantial amount of unsaturated polyester is particularly advantageous from this point of view.

Had, which contains soluble binder *, know la la weeentliohen the same way as had, dl · Contain a hardened insoluble binder that heals the bars in powder form or in the form of a LOmBf or atoe can be applied, the solvent or dispersant of the solution being evaporated in the latter two cases. Bs is only heated to the extent that the fiber is melted and the fibers of the mats are connected. Since a soluble binder is desired, curing is not required, ioh. In the trade, fiberglass mats are old

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most binding resins, both soluble and insoluble, are available. A quick test to determine whether a given commercial mat is suitable for use in the method of the invention is that the mat is immersed in acetone. If the mat to be used according to the invention dissolves rapidly in this treatment, then the mat is suitable · Also can the commercial mat can be immersed in a certain amount of the polymerizable composition which is used in the Manufacture of the plate should be used, thereby determining the solubility or insolubility of the binder of the mat will ο

The invention is illustrated in more detail by means of the following examples.

example 1 Herste? Lu n /; the mat:

A polyester is made by having equimolecular Amounts of maleic anhydride and isophthalic acid with diethylene glycol, to which 1-10 moles of neopentylene glycol have been added

ind, to be mixed «The glycol is preferably used in one about 5 in excess of that required to react with the acid and anhydride. The reaction mixture is heated in the absence of air »in order to effect esterification and · elimination of the water ·», to «in · acid number voa. 50 or less has been obtained or until the reaction product sioh on cooling Solidified at room temperature.

The resulting polyester is then applied in powder form as BIaA resin to a mat made up of continuous oil fiber strands produced as described above. The powder is applied in an amount of about 5-7 ow.-Jt based on the mat, and the mat is sdt de · Resin heated to 120-150 ° 0 to soak the Hars. The GE-

Molten resin preferably collects at the contact points. Glass fibers and connects them at Cooling down, creating a self-sustaining structure that can be easily handled. After rolling, the Was ready for use in the method according to the invention o

Herst RECOVERY the Formmasset

EiA resin flask At a stirrer with stainless Stahlechaufeln, a thermometer, a gas inlet tube, a condenser and a means Destillationekopf with sum collecting equipped 1st developed ¹ fluids, is charged with 1067.8 parts of fumaric acid. To this end, 435 parts of 1,4-butanediol and 5 ", 5 parts of diethylene glycol are added. The molar ratio between anhydride and the glyools is 1x1.05. The reaction mixture is heated with a thermostatically controlled oil bath. Nitrogen is chemical throughout the esterification The reaction mixture is ^{heated to 190 °} C. and kept at this temperature for 2.5 hours. After this time, most of the water is distilled off ⁰ C is reduced and 0.01 parts of hydroquinone are added as a stabilizer.

The resulting polyester is made with methyl methaorylate monomer mixed in proportions such that a mixture bit of polyester / methacrylate ratio of 75:25 is obtained. To 125 g of this mixture, 52 g of calcined calcium elicate, 41 g of calcined aluminum silicate, 22.6 g of chlorinated hydrocarbon (Deohloran from Hooker Chemical Co.) are added. and 9.4 g of antimony oxide were added. The mixture is stirred vigorously to produce a smooth homogeneous mixture and is catalyzed by the addition of 1.25 g of benzoyl peroxide.

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Deformation process;

Bin piece of electrolytic copper foil -from 0.035 mm thickness and having the size of 91 _f 4 x 121.9 cm is placed on the horizontal surface of a aluminum bar. The molding compound produced according to the above procedure is poured onto the copper foil in an amount of 3 kg / m 2. This amount of standard mass results in a laminate with a thickness of 1.59 mm.

A piece of resin-bonded glass mat, made as above, is cut a little larger than the copper foil, i.e. 96.5 x 127.0 cm, and placed over the viscous molding compound _o A piece of release paper is placed on top of the mat, and then a suitable aluminum plate, which has a ridge around the entire circumference, is placed over the mat and the molding compound. The circumferential web on the aluminum plate is used to control the thickness of the plate to be produced. The resulting assembly is placed in a press and cured at a pressure of 8.75 kg / cm and a pressure of 118 ^° C. for 6 minutes, then removed and cooled.

The copper-clad board made according to the invention was placed in a Profioorder * surface fore meter manufactured by Micrometrical Co. is tested to determine the smoothness of the exposed surface of the film. It was found that the surface of the Film had a smoothness of 0.05 mm. In contrast, a plate made by the above procedure showed with the difference that a mat with an insoluble binder replaces the mat with the soluble binder was used, a · surface smoothness of 0.07 ■ ».

Example 2

The plate was produced by the method of ExampleΊ, with the difference that the molding compound of Example 1

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was replaced by a Foromaee, which is produced in the following way:

(a) A polyester is produced by mixing 1.1 mol of maleic anhydride and 1.0 mol of ethylene glycol and heating the resulting mixture to 193 °° _? "until #in» acid number of 153 has been obtained »

(b) A solution of methyl methacrylate polymer ia de «Moaoi ^ r is made by dissolving 54 g of methyl methacrylate, sold under the trademark Lucite 40, in 96 g of methyl methacrylate, which contains 0.006% hydroquinone as an inhibitor. Dissolving the polymer in the monomer is effected by the Gemisoh is heated with stirring to 65 ⁰ C "After the polymer has dissolved in the monomer, 100 g of calcium sulfate having a XeilehengrHS 'of 0.075 mm and below, and eye give 1 g Benssoylperoxyd and mixed with the solution. 1 g of the polyester described in paragraph (a) is then incorporated into the mixture. The deformation process used is the same as in Example 1 "

A kasoblertfe plate made according to this example was tested and it was found "that it" had a surface smoothness of 0.079 mm. A plate made by the same process, but using a mat made with an insoluble binder showed a surface smoothness of 0.193.

Bine Platt was produced according to the method of Example 1, with the difference that the porenaesis of the Example by a forrama made as follows:

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A ^r ölye3tfti wiiu fliiitareh manufactured that 116.1 Sell «fuourväu: ** - -mV- 3?» ^ Parts 1 _# 4 ~ Butr'.nlLol, 12.5 parts 1,6 hexanediol, 16, ί -. - ΙτΙ '' - ·. '\ ./ 2 ^Λ ·? and 2β Tr-il «& F ^ r glycol are mixed. 28 Teixe of the resulting polyester are heated to 94-65 ⁰ C, and 12 parts of methyl methacrylate monomer are added. To this mixture are added 6.0 parts of chlorinated hydrocarbons (Dechlorane, sold by Hooker Chemical Co.), 5 "5 parts of antimony oxide, 19" 5 parts of carbonated aluminum silicate (Satintone Io. 1) and 18.0 parts of calcium metasilicate ( Cabolite Pl) sugesets. The resulting composition is carefully mixed and allowed to cool to room temperature, after which 0.5 part of benzoyl peroxide is carefully mixed in.

To 450 g of the filled Formharees which has been prepared in this manner, 50 g epozydiertes Soyabohnenul having a molecular weight of 950 and a τοη Oziransauer off st content of 7.1 / · · The added Zusammenaetssung is sur production uses a plate wöbe ⁴ the deformation process used in Example 1 is applied,

A copper-clad board made by the above method was tested and found to be a Had a surface smoothness of 0.051 mm. A panel made by the same procedure but using a mat containing an insoluble binder showed one Surface smoothness of 0.066 mm.

Example 4

An insoluble binder for a mat from a continuous strand of fibers is made by using a 50/50 uemleoh of fumaric acid and phthalic acid is esterified with propylene glycol up to an acid number of 150. Thereupon 35

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Methyl methacrylate based on the weight of the ester is added to and mixed with the ester. The resulting mixture is emulsified with water and applied to a mat of continuous glass fiber strands as a binder resin. The treated hat is ^{heated to 120-15O 0} C in order to melt the resin and to volatilize the methyl methacrylate and the water.

The bound hat made in this way is used for manufacture a copper-clad plate is used according to the procedure ▼ on Example 1 and results in a plate with a smooth Surface.

It will be understood that the above examples are illustrative only and that changes may be made in the ingredients, proportions and conditions mentioned in these examples. A wide variety of commercially available products can be used as soluble binders on the reinforcement mat. For example, the binder resin can be a polyester of fumaric acid and ethylene glycol sold by Marco Chemical Co. * under the designation PE-301. Various commercially available polyesters such as those disclosed in U.S. Patents 2,662,070 and 2,654,251 can also be used as the binder resin for the hat. In particular polyester can be used as soluble binders which form non-tacky at room temperature and solids are below 150 ⁰ C easily fusible. Finally, instead of those described in the examples, other molding compounds can also be used in the manufacture of the boards for printed circuits *

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Claims (1)

r t a η ο ώ:. ' Il ο 1. ftii ^ er> Rschi vrh ι Γτατ, ρϊ ^ otfpla **! * F-ii * printed ft So & itittmgen, Lch «au ?. e: Laar Ei ;, ₍ > .ftrfa "iG un ^f i apart from the ! ■;: ärktem Kunet ^ taifsubstrat be "t $ kt wherein diedes substrate from a IIA-t'se" beiteht the ccmsirc Crlasfaaer3trängö contains & lt characterized g β -ί ß η ae 1 ch net that the fibers άητ * iatte are connected to one another only by Ί ?? ι Kun & tetoff of the substrate. 2 ο Process for the production of an icupfarkasch3rten plastic plate for printed circuits, in which a liquid polymerisable Ztt3aftfH <mBetsrang on the copper foil at an elevated temperature and a higher. Polymerization takes place under pressure in contact with the film, with a reinforcing material made of resin-bound, endless glass fiber strands in the polymerizable composition, characterized in that the processing mat used is bound with a binding resin, as the polymerizable ZuaannnensetÄujig is soluble " 3 · Method according to claim 1, characterized net that the bindehars of the mat consist of a -doeeeaturated solid polyester and the polymerisable® portion of the polymerizable composition is a mixture of an unsaturated polyester and methyl methacrylate * 4 β method according to claim 3, characterized in that net that a solution of polymethyl methacrylate in methyl methacrylate monomer is used 009832/1713 bad ORr _G , _NAIL 2ÜÜ39P2 «14 - 5o method according to address ') _f thereby - <j β kta »^ β e *> net that the mixture tv.is ur ^ ee &' tti ^ v? Ia polyester and * methyl methacrylate contains an epoxy. 6 ο method according to one of claims 2 bia 5, characterized
characterized that 3 ie 1ιεχζρ * Μ ^ Α «ι? hy, - 'a made of continuous glass fiber ^ ßtrSjßfer' on -lie obeita Obex «surface of a copper foil placed tfird * the» i &, n £ B'Lny. Ιφ substantial horizontal porous surface is located, s? <; 1 3 mat with a viscous liquid polymerici ^ rliaren Kuira mensetzung impregnated therein and eiigepchlcssen ISSI _"f un * ι then the impregnated mat and the copper foil
Pressure brought to an elevated temperature *, κτ & β] ΐ ₉ to produce the plate. BAD ORfGJNAL 009832/1713