DE3510529A1 - POLYIMIDE PRE-POLYMER COMPOSITION, PREPREG AND METHOD FOR PRODUCING A LAMINATE FROM THE PREPREG - Google Patents

Description

MATSUSHITA Electic Works, Ltd. 1048, Kadoma, Kadoma-Shi, Osaka 571, JAPAN

"Polyimide prepolymer composition, prepreg and method

for producing a laminate from the prepreg "

Priority from the Japanese patent application

The invention relates to a polyimide prepolymer composition according to the preamble of claim 1, prepregs according to the preamble of claim 4 and a method for producing a laminate according to the preamble

20 handle of claim 7.

These are polyimide prepolymers that are produced by an addition reaction using these prepared prepregs as well as a process To produce laminates using these prepregs, in particular to produce such compositions and Processes such as are suitable for the production of multilayer boards for printed circuits.

Various epoxy resins are widely used for the production of multilayer boards with printed circuits that has valuable properties including superior adhesive properties, considerable toughness to chemicals, high mechanical resistance and excellent dielectric properties

own. However, it has been found that epoxy resins are no longer suitable for the production of multilayer boards with printed circuits are suitable, the circuits with high p. Packing density and modules, as they are resistant to heat, applied to such printed circuit boards when attaching modules, is not sufficiently robust are; in addition, they often impair the reliable conductivity of conductive layers due to possible resin leakage or heat expansion in the direction of the panel thickness. To the above problems To circumvent, heat-resistant polyimide resins are currently used and have been found to be for the manufacture of printed circuits

Multi-layer panels are satisfactory. 15th

In particular, polyimide resins are of the addition reaction type obtained by reacting unsaturated bis-imides with diamines most suitable for the Manufacture of multilayer boards for printed circuits, as the use of this material is remarkable and brings advantageous features with it. Among these beneficial features obtained by using this Material are to be expected, there is the possibility of

forming fine conductive lines, as well as drilling 25

of small holes with high accuracy, which are indispensable for the arrangement of high-density circuits; the Thermal expansion in the direction of thickness is kept to a minimum in order to increase the reliability of the conduction in to ensure continuous holes coated with conductive material; the build-up of leaked resin to eliminate during drilling; to give conductor layers increased adhesive forces, as well as to the bases of the printed circuit boards at elevated temperatures

to give greater hardness to the behavior when attaching 35

To improve modules; and a continuous operation

Can withstand high temperatures of around 200 ° C.

U.S. Patent 3,562,223 issued to Michael Bargain et al

such polyimide prepolymers with valuable properties ο

described, there is the teaching that they can be prepared by reacting unsaturated bis-imides with diamines are.

Meanwhile, today's increasing miniaturization of large scale computers has made it possible to use multi-layered printed High density circuit boards requiring much finer circuit patterning and a much finer drilling of through holes. As a result

should use the printed scarf-15

boards have a higher dimensional stability with superior adhesive properties.

That is, there is a possible variance in the dimensions of

Plates heavily the interlayer or intermediate 20

level entry can influence. Accordingly, dimensional changes should be kept to a minimum; this is particularly important for the production of multilayer boards of larger dimensions. Accordingly, it is preferred the printed circuit boards with such a low-25

To form some pressure that the dimensional stability is not reduced. But there still remains the problem that molding at such a low pressure level sometimes does not result in a successful smooth flow of the

Resin passes through the curing plates or not every 30

Traces of solvent, which was used for impregnation purposes, are eliminated, reducing the presence unacceptable voids is caused in the molded printed circuit boards. With regard to the adhesive properties

is required for the production of circuits with a high 35

Packing density a correspondingly high adhesive force, not only

-ΟΤΙ

between the conductor layer and the connection layer, but also between the connection layer and the Base material or core of the plate; otherwise there would be slight delamination in the intermediate layer between Compound layer and the base material occur during the drilling of the small holes, such Detachments are unacceptable and should of course be avoided.

In view of the above, it is desirable that multi-layered printed circuit boards for use in large computers have much higher adhesive forces with much greater dimensional stability combine. In other words, prepolymers and the prepregs made from them should contain the

for the manufacture of the multilayer printed circuit boards are used, show much higher adhesive forces and also the shaping of the plates in such a way allow low pressure level to ensure dimensional stability without disadvantageous cavities in the resulting plat-

ten not to deteriorate.

Prior art prepolymers including in the aforementioned US patent, are known to have

excellent adhesive strength together with other bemer-25

have remarkable features, unfortunately they are for the manufacture of the multilayer printed circuit boards of the type with a larger number of layers, which has a higher level of dimensional stability and increased Adhesive properties needed, still unsatisfactory. That is, polyimide prepolymers after Prior art is likely to suffer from inadequate adhesive properties when such multilayered printed circuit boards are produced and also form disadvantageous voids when they are in at low pressure an attempt to ensure dimensional stability -

be formed.

Investigations of the above unsatisfactory results using prior art polyimide prepolymers the technique habai shown that macromolecular components with a molecular weight of more than 15,000, which are present in a larger amount, for the above unsatisfactory Adhesion properties and the appearance of voids when molding with low pressure may be responsible. In fact, the components with a molecular weight of over 15,000 have a high viscosity, which requires a larger amount of solvent for the impregnation and therefore a greater chance for the

, _ Inclusion of residual solvent in the printed 15

Circuit board offers when molding at low pressure, eliminating the disadvantageous voids in the boards be left behind. It is also characteristic of the above macromolecular components that they interact with one another Substrates with which they are in contact for bonding therebetween have low sensitivity or have activity, such decreased sensitivity or activity being the cause for failure of an integral bond with the

Will be substrate, whereby lower adhesive forces between 25

them result. As can be deduced from the above consideration, it is used by polyimide prepolymers for the present purpose expects these to be less macromolecular components with molecular weights in excess of 15,000 than previous ones Possess prepolymers. Conversely, it is expected that prepolymers with a greater proportion of components with a Molecular weights of less than 15,000 will be preferred. With this default, the inventors have the adaptability of polyimide prepolymers to the fabrication of multilayer printed circuit boards and others Laminate products further investigated and found that

Polyimide prepolymers, the specific component proportions contained in a specific molecular weight range, based on other components in the Prepolymer composition, for the creation of satisfactory properties for the production of multilayer printed circuits are responsible.

It is the object of the invention to provide new and usable polyimide prepolymer compositions to create which ones are used for the production of laminate products or multi-layer panels for printed circuits have advantageous properties, such as excellent dimensional stability and high mechanical resistance.

According to the invention, new prepregs are also to be created which use these prepolymer compositions are producible and are particularly suitable for the production of the above-mentioned multilayer printed circuit boards suitable. Furthermore, a method for the successful production of laminates for printed circuits is to be created.

The object is achieved according to the invention by means of a polyimide prepolymer composition dissolved, which is characterized in that the composition was about 30-4056 unreacted Reactants, 53-65 / 6 components with a molecular weight of between 400 and 15,000 and 3.5-6.8% components with has a molecular weight greater than 15,000.

A prepreg according to the invention is characterized in that the resin is approximately 18-28% unreacted after curing Reactants, 55-70% components with a molecular weight between 400 and 15,000 and 7-10% components with has a molecular weight in excess of 15,000.

The method according to the invention for producing a laminate is characterized by a predetermined superposition Number of prepregs according to one of claims 4 to 6; Application of metal foil (s) to one or both of the exposed ones Surfaces of the prepreg stack and making a laminate by applying elevated temperature and pressure to to cause the prepregs to cure and the metal foil (s) to adhere.

The symbols A and B can have the same or different meanings have and can have linear or branched alkyl groups with less than 13 carbon atoms, Cycloalkylene groups with 5 or 6 carbon atoms in the ring, heterocyclic groups with at least one of the atoms O, N and S or a phenylene or a polycyclic aromatic group. These different groups can Carry substituents which themselves do not enter into any undesired side reactions under operating conditions. the Symbols A and B can also mean several of phenylene or alicyclic groups, directly or via a divalent atom or group, such as oxygen or sulfur, an alcylene group of 1 3 Carbon atoms or one of the groups are attached:

25 -NR ₄ -, -P (O) R ₃ -, -N = N-, -N = N-, -CO-O-, -SO ₂ -,

-SiR ₃ R ₄ -, -CONH-, -NY-CO-X-CO-NY-, -O-CO-X-CO-O-,

-CH-30

35 ^and

where R3, R4 and Y are each an alkyl group of 1-4
Carbon atoms or a cycloalkyl group with 5 or 6 carbon atoms in the ring, or a phenyl or a polycyclic aromatic group, and X is a straight-chain or branched alkylene group with fewer than 13 carbon atoms, a cycloalkylene group with 5 or 6 carbon atoms in the ring or a mono- or polycyk-

Lische arylene group is.

Group D is derived from an ethylenically unsaturated anhydride of the general formula:

CO

for example maleic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, itaconic anhydride and Products of the Diels-Adler reaction between a cyiodiene and one of these anhydrides can be.

Among the Ν, Ν-bis-imides (I) which can preferably be used, one can

name the following:

N, N'-ethylene-bis-maleinimide,

N, N'-hexamethylene-bis-maleinimide,

N, N'm-phenylene-bis-maleimide,

N, N'-p-phenylene-bis-maleimide,

N, N '-A ₁ 4'-Diphenylmethan-bis-maleinimid, N, N'-4,4'-Diphenyläther-bis-maleinimid, N, N ^l -4,4'-Diphenylsulfon-bis-maleinimid,

N, N'-4,4'-diclyclohexylmethane-bis-maleimide N, N ¹ -, -4,4'-dimethylene cyclohexane-bis-

maleinimid,

N, N'-m-xylylene-bis-maleimide and N, N ¹ -4,4'-diphenylcyclohexane-bis-maleimide.

The following can be named as examples of diamines that can be used:

4,4'-diamino-dicyclohexylmethane,

1, 4-diamino-cyclohexane,

2,6-diamino-pyridine,

m-phenylenediamine,

p-phenylenediamine,

4,4'-diamino-diphenylmethane,

2,2-bis (4-aminophenyl) propane,

Benzidine,

4,4'-diaminophenyloxide,

4,4'-diaminodiphenyl sulfide,

4,4'-diaminodiphenyl sulfone, 25th

Bis- (4-aminophenyl) -diphenylsilane, bis- (4-aminophenyl) -methylphosphine oxide, Bis-O-aminophenyD-methylphosphine oxide, Bis (4-aminophenyl) phenylphosphine oxide,

Bis (4-aminophenyl) phenylamine, 30

1,5-diaminonaphthalene,

m-xylylenediamine,
p-xylylenediamine,

1,1-bis (p-aminophenyl) phthalan and hexamethylenediamine

1
The ratios of the individual components and unreacted reactants depend on the ratio of the peak areas determined with reference to known calibration curves, which the

j- ratio between molecular weight and that in one Chromatography procedures show certain retention times, the details of which are explained below. The relationship of unreacted reactants or unsaturated bisimides and diamines, which are found in the prepolymer

- composition can be an indication of the reaction process and indicates when it is below 30% finds that the reaction has proceeded too far and has more undesirable components with a molecular weight of more than 15,000 to an unacceptable level

has produced, whereby the adhesive force is reduced, and 15th

then, if it is above 40%, indicates that the Reaction has not progressed sufficiently to form a sufficient amount of prepolymerized components, which are necessary for the production of a prepreg with the correct resin content. I.e. that without a A sufficient amount of prepolymerized components is produced, the overall composition too little is viscous when in a polar diluent or solvent, such as N-methylpyrrolidone or dimethylacetamide

is dissolved to create a substrate for the manufacture of the 25th

To impregnate prepregs with it and leads to the fact that a prepreg with the correct resin content cannot be produced can. Under these circumstances it is also hardly possible to increase the resin content of the prepolymer solution in order to avoid the lack of

To compensate viscosity, since it does not react in the 30th

Prepolymer composition remaining bisimides in one such solvents have low solubility. There is a preferred proportion of unreacted reactants between 35 and 39%.

The components with a molecular weight of between 400

1
and 15,000 exhibit satisfactory properties for the manufacture of laminate products or the desired multilayer printed circuit boards, that is, when dissolved in the solvent, they form considerable adhesiveness as well as a solution of suitable viscosity, thus thus impregnating the substrate with the solution It can be said that molding at low pressure is possible without occurrence of defective voids. In

- This connection is assumed that components with a molecular weight of between 400 and 15,000 they should preferably be used in the highest possible amount in the prepolymer compositions, although if an excess of such components is produced,

this means that the reaction process according to Ib

continues to progress and accordingly in a growing amount of these undesirable macremolecular components ends with a molecular weight greater than 15,000, with these components being kept to a minimum

should in order to reduce the adhesive properties 20

impede. From this point of view, it is preferred that the proportion contain components having a molecular weight of between 400 and 15,000 does not exceed 65%. The lower limit for the amount of the above components is for 5356,

__ has been determined if it is below 5 3% 25th

more unreacted reactants remain, so that the prepolymer composition falls below the above Inadequacies such as a lack of viscosity when dissolved in the solvent would suffer.

The components with a molecular weight of more than 15,000, when manufactured in larger quantities, will accelerate curing in the subsequent operation and shorten the curing time. The above components are however, undesirable objections in the prepolymer composition according to the present invention because they are for the

3510579

Occurrence of defective voids in the molded end products as well as a loss of adhesive forces such as already explained above, are responsible. The prepolymerization process cannot do without the manufacture of such macromolecular components are carried out, i.e. such components are carried out immediately after the start of the Prepared prepolymerization reaction. As a result, macromolecular components are unavoidable .Q Production of prepolymers occur, preferably on a kept a minimal but not negligible value. In practice, it is preferable to use the amount of these Limit components to between 3.5 and 6.8%. Below 3.5% the prepolymerization process would not

._ advance sufficiently so that the resulting prepoly-Io

mere composition when dissolved in the solvent suffers from a lack of viscosity, whereby the production of Prepregs with a suitable resin content is not possible. In contrast, prepolymers are used above 6.8%

Composition more undesirable macromolecular compo-20

contain components, so that the solution of the prepolymer has too high a viscosity, which from the above Reasons is not desired.

In connection with the above, the inventors have the 25th

Separated components having a molecular weight in excess of 50,000 believed to be are representative of the properties of the above macremolicular components and analyzed them. The severed ones Components were dissolved in D-DMF (deuterated dimethylformamide) and analyzed by means of an NMR spectrometer. the Analysis shows that the above components hardly contain any diamine and essentially consist of polymerized product, only of Bisimides, of which it is known of these products

that they have less elasticity and less adhesive properties 35

exhibit. This confirms that the amount is macromolecular

Components should be kept at a minimum.

In the present invention, the determination of the molecular weight distribution of the prepolymers and prepegs depends on gel permeation chromatography (GPC) analysis by means of a chromatography device HLC-803 (manufactured by Toya Soda Manufacturing Co., Ltd.) equipped with a pair of chromatographic columns Ad -80 3 / S (manufactured by Showa- ₀ Denko KK, Japan) 8.0 mm in diameter 250 mm in length, packed with divinylbenzene sterol copolymers filled with micron-sized particle sizes. Dimethyl (-DMF) formamide was used as a diluting solvent. Each column has about 6000 theoretical plates,

so that the above column system has an effectiveness of 12,000 Ib

theoretical soils. A 100 microliter sample of a solution with a polymer content of 0.5 + _ 2 percent by weight (resin content / DMF + solvent contained in the prepolymer or prepreg) was injected into the column at an elution rate of 1.0 +. 0.01

20 "" "

Milliliters per minute was maintained. A differential refractometer (128 χ 10 "^ RI units) was made
used together with a recording device which had a paper speed of 5 mm per minute, and a

Paper log on paper with uniform surface density 25

delivered, with a wave-shaped recording indicating the eluate concentration. The refractometer was on a Output range set between 0 to 1 V, corresponding to the selected input range from 0 to 10 mA

of the recording device. For the determination of the molecular 30

Comparative samples used were 5 kinds of monodisperse polyethylene glycols having molecular weights of 20,000, 10,000, 6,000, 4,000 and 400 plus an ethylene glycol monomer having a molecular weight of 62.

The calculation of the molecular weights was carried out with a 35

quadratic regression curve or calibration curve performed,

determined for each of the above reference samples to give a ratio between known retention time and associated molecular weight, so that the molecular weights of the sample by applying a corresponding retention time and one of the existing regression curves can be determined. The determination of the Molecular weight distribution or that in percentages of components with different molecular weights The total resin content of the sample was expressed as a percentage ratio by a so-called separation-weighing method carried out, the protocol paper of uniform density, which with the GPC signals or the The chromatogram of the sample was described, cut into pieces, each of which was used to determine the proportion Represented components with a specific molecular weight range, and each fraction for Determination of their ratio to the total amount of the fraction weighed was weighed. Before determining the above Ratios, the index molecular weights were set at 15,000 and those for unreacted reactants, that remain in the sample prepolymers or prepreg, for each molecular weight for which a corresponding Retention time was obtained from the above calibration curves. The GPC paper protocol was then transferred to the corresponding number of fraction areas below the recorded GPC curve between those for the above Molecular weights cut representative of specific retention times. Each of the factions became accurate weighed to determine their ratio to the whole, the ratio indicating the ratio of peak areas and the weight proportion of special components to the total resin content of the prepolymer or prepreg approximately supplies.

Alternatively, use an integrator for easy calculation

of the above fractions are used by partial quadrature, with each fraction of the chromatogram in at least 200 Step sections for a reliable calculation

_c would have to be subdivided, b

The unreacted reactants remaining in the above prepolymer composition are preferred at a molar ratio from bisimide to diamine from between 1.7 to 3.0 held. Namely, when the ratio is higher than 3.0, the resulting prepolymer composition shows if it forms a solution or prepreg with suitable resin content, disadvantageously precipitating excess Bisimides during its storage and, if the ratio is less than 1.7, the one used for curing the

resulting prepolymer in the subsequent process step of prepreg production and / or end product production reduced significantly to such an extent that control of the curing would be difficult.

In fact, the inventors' study showed that the above molecular ratio of the prepolymers according to the prior art Technique ranged between 3.5 and 4.1 and that prior art prepolymers at room temperature were hardly dissolved in the polar solvent and 25

only when heated to solution to make the solution an appropriate concentration of about 50 to 60 Were enabled.% Were, and also that the solution or the paint so prepared when heated with the precipitation of the

Bisimids suffered during storage. In contrast to the above 30

has been used for prepolymers according to the present invention in which the unreacted reactants are in molecular ratio held from bisimine to diamide of between 1.7 and 3.0 are found to have essentially no failure, not just during normal storage conditions 35

Room temperature, but also when stored in a cold place

1 temperature of -5 ⁰ C, show.

The above molecular ratio of unreacted reactants was calculated from the number of moles determined by the following method. That is, the prepolymer was dissolved in acetonitrile to dissolve selectively unreacted reactants in this and were then analyzed the dissolved constituents in acetonitrile to qantitativ to determine the Reek _n tanden, and their number of moles by liquid chromatography using a reversed-phase partition chromatography column 120T (manufactured by Toyo Soda Manufacturing Co Ltd.) using acetonitrile-water as a diluent. before

, _ The above procedure was a calibration curve for each of the 15th

Reactants determined to give the relationship between the number of moles and peak area, and the calculations of the number of moles of the Appropriate reactants were carried out by adding the measured peak value to the appropriate calibration curve

was applied. 20th

Prior to the above determination, the acetronitrile was insoluble and therefore still remaining in the prepolymer in DMF for the purpose of analyzing the same by gel

permation chromatography, this being no peak 25th

which indicated the presence of unreacted reactants and consequently confirmed that unreacted Reactants had been completely dissolved in acetonitrile and extracted with this.

The prepolymer composition according to the present invention having the above specific component ratio shows superior adhesion to the substrate as well as exceptional heat resistance, in contrast to that

Prior art prepolymer compositions with 35

the specific component ratio not available

1
was. Indeed, examination of the commercially available prepolymers showed that they contain fewer components with a molecular weight between 400 and 15,000 and many more components with a molecular weight in excess of 15,000 compared to the prepolymer composition according to the present invention.

The prepolymer composition of the present invention can be prepared by reacting unsaturated bisimides with diamines in a common diluent at a relatively low temperature of below 95 ° C, preferably at a temperature of between 60 and 90 ° C. On the other hand increasing method according to the prior _lt - technique for producing Polyimidpräpolymeren at elevated temperatures of between 120 ° and 20 0 ° C either in the melt or in solution normally Präpolymerisationsreaktionsgeschwindigkeit, as has been found, so that an excess of macromolecular compo- _ nents having a molecular weight in excess of 15,000, although the amount of unreacted reactants was effectively decreased. In an attempt to control the prepolymerization process so that the macromolecular components having a molecular weight of., _ Over 15,000 are maintained at an optimal ratio of between 3.5 and 6.8%, it has been found that the prepolymerization reaction at the elevated temperature from 120 to 200 ⁰ C leads to an inadequate reaction process and consequently to an unnecessarily higher amount of unreacted

Reactants used in the resulting prepolymer-30

composition remain. This tendency not to let reactants react in larger amounts is paramount, when the prepolymerization reaction is carried out in melts at a higher temperature. Furthermore, this leads

Prepolymerization reaction in melts an excess amount 35

macromolecular components with a molecular weight of

more than 15,000 in addition to the fact that unreacted reactants were in excess, thereby creating an extreme deficiency of Components with a molecular weight of between 400 and 15,000 arises, these being the effective components for the manufacture of prepregs and manufacture of the laminate end products are, as already mentioned.

1 The above prepolymerization reaction, which takes place in solution at a lowered temperature of between 60 and 95 ° C for the preparation of the polyimide prepolymer according to the following invention normally takes 2-10 hours, although the exact reaction time depends on the selection of specific reactants, the polar diluent, the concentration of the solution and the Reaction temperature and can therefore deviate from the above range under certain conditions.

10

The molar ratio of unsaturated bis-imide to diamine des present prepolymers is preferably adjusted to between 1.7 and 2.5, in view of the fact that, if it is below 1.7, macromolecular weight components are produced in larger quantities and at the same time the curing time is reduced considerably to such an extent that the handling or control of the Reaction process is made more difficult. If it is above 2.5, reactants remain, especially unsaturated ones Bis-imide, unreacted and are contained in a larger amount in the resulting prepolymer composition, whereby the unsaturated bis-imide tends to precipitate during storage of the prepolymer solution. The above molecular Ratio was determined for the final solution of the prepolymer composition, hence both or either the reactants at intervals during the prepolymerization process may be added or part thereof after completing the procedure, if necessary to be admitted.

30th

The new prepreg also created in accordance with the present invention was made by impregnating a suitable substrate with the solution of the polyimide prepolymer produced by an addition reaction, which is used in the above Way was made, produced, followed by

partial or semi-curing of the prepolymer as well as by evaporation of the solvent in such a way that the resin content of the same between 18 and 28% of the unreacted reactants (., with 55 70% of the components having a molecular weight of between 400 and 15,000 and 7-15% of the components have a molecular weight of more than 15,000 own. The prepreg with this specific component ratio can only be made from the above polymide prepolymer composition can be made according to the invention and alone can determine the successful shaping Ensure laminate products at a low pressure level without leaving voids in final Laminate products remain. When the ratio of the

unreacted reactants reduced to less than 18% 15th

and that of components with a molecular weight of between 400 and 15,000 exceeds 70% and that of Components with a molecular weight of more than 15,000 exceeds 15%, the latter become macromolecular components predominantly so that it increases the viscosity of the resin 20

unnecessarily increase what is sure to result in voids in the laminates when manufactured using a low pressure molding process leads. With the above conditions, the subsequent curing for the production of the laminates in one would be too

short period of time than to complete a successful 25th

To enable the production of laminates of larger dimensions.

When the percentage of unreacted reactants is above 28%, that of components having a molecular weight of between 400 and 15,000 is less than 55% and that of components with a molecular weight of more than 30

than 15,000 is less than 7%, a larger amount of resin will leak out of the substrate in the subsequent molding process, which leads to severe thickness variance in the resulting laminates, in addition to being larger Amount of solvent remains in the substrate, which leads to the formation of bubbles in the resulting laminates. The compo-

Components with a molecular weight in excess of 15,000 are preferred is kept to a minimum for the same reasons discussed for the prepolymer composition.

As already mentioned, the prepolymers contain according to the prior art large quantities components having a molecular weight of about 15,000 as the inventive prepolymer composition, and can not consequently, the - supply _n prepreg with the above components ratios, regardless of which Aushärtbedingung is selected.

The substrate which can be used for the preparation of the prepregs includes glass cloth, inorganic cloth such as made of quartz fiber

, _ manufactured, and other heat-resistant fabrics such as Keblar,

a fabric of the Dupont.

The above semi-curing process for making the prepreg can preferably be carried out at a temperature between 130 and 155 ° C, since at a temperature of Above 155 ° C the process is accelerated so that there are larger amounts of undesirable macromolecular components produced and at a temperature below 130 ° C that Prepreg cannot be produced efficiently.

The laminate products can be made by doing so on top of any number of prepreg layers so made according to the invention conductive layers of metal foil, such as copper or nickel, are laid, followed through complete hardening through the action of heat and pressure. Due to the superior properties of the aforementioned prepregs by allowing the manufacture of laminate products measuring 50 cm by 50 cm and even larger Dimensions in the plane with only a low pressure of

less than 15 kg / cm ^ allows without any
35

If cavities occur in the end product, this stands out

1
compared to the commercially available prepregs, which require a higher pressure level of more than 40 kg / cm ^ to prevent voids, the laminate products produced according to the invention having a high dimensional stability in addition to the fact that they enjoy superior adhesive properties, as they do with the above prepolymer composition according to the invention. Accordingly, laminate products of the invention may be useful in the manufacture of multilayer boards for printed circuit boards which require a very compact circuit and module arrangement.

The following examples serve to illustrate the present Invention.

Example: Tables 1 and 2 comprise Examples 1-6 which are representative of the compositions according to the invention are, as well as Comparative Examples 7-11, which are listed for comparative purposes. In the comparative examples Examples 7-10 correspond to prepolymer compositions of the aforesaid US Pat. No. 3,562,223 and Example 11 shows a polyamide bismaleimide prepolymer one commercially available available type, which is available under the trademark Kelimid 601

distributed by Rhone Poulenc, France. 25th

Table 1 follows:

Table 1

Ratio agents (g) & conditions

Example No. ι Comparative Example No. 12 34 * 5 611 2 34 56 7 8 9 10 11

N, N'- 'methylene bis (N-phenyl maleimide ) *1

4 _f 4'-diamino diphenylmethane

N-methyl pyrrolidone "

N, N-dimethylacetoamide '■

940 911 972 906 987 982 940 940 987 831 860 972 78.32 78.32 78.32 78.32 260 229 269 294 273 217 260 260 273 230 340 168 21.68 21.68 21.68 21.68

1040

800 860 760

740 800

800 - 940 800 - 67.0 67.0 67.0 67.0 960

- - 860

Temperature ( ^{( 1} oil 80 90 70 65 80 95 80 80 110 160 70 105 130 100 100 100 Time (min) 240 210 330 160 180 170 180 370 130 8th 120 150 15th 3 40 90

♦ 1 »-CO. .CO-

L> o - <»> - o- < _co .

NH ₂ - / \ -CH ₂ - / \ -NH ₂

In Examples 1, 3 - 6 and Comparative Examples 1, 3, 5 - 10, each set of raw materials was expressed in weight (grams) in Table 1 is placed in a 3 liter four-necked flask to be mixed therein.

After inserting the stirrer, thermometer and cooling device In the flask, nitrogen was introduced into the flasks through a side neck to replace the atmosphere in the flask. The mixture was then heated to a temperature shown in Table 1 in an oil bath while was stirred until dissolution began. After stirring for a period of time listed in Table 1, the resulting The solution was cooled in a water bath to room temperature in 15 minutes and yielded a blackish-red prepolymer solution.

In Example 2, a total of 911 g of bis-imide was used in added twice in partial amounts to an interval. First, 828 g of bis-imide were used to create an appropriate mixture to prepare for the reaction in the same manner as above, after which 83 g of the remaining bis-imide to be mixed at a Temperature of 90 ° C was added to be completely dissolved in the same. The resulting product was then cooled to give a prepolymer solution.

In Comparative Example 4, N, N ¹ -methylene-bis (N-phenylmaleimide) and 4,4 ^1- diamino-diphenylmethane in the prescribed amounts were introduced evenly in portions within 1 minute into a heated stainless steel reaction vessel, which by means of an electric heater device had been sufficiently heated. Then, after the mixture had melted, it was stirred and kept at a temperature of 160 ° C. for 8 minutes. Subsequently, the resulting product was spread in a thin layer on a steel plate which had been sufficiently cooled and delivered

1
yellowish solid product. The product was made using a

Grind the mortar and then heat it to 40 ° C

N-methylpyrrolidone dissolves, after which the solution dissolves

Was cooled to room temperature and gave a dark red prepolymer solution.

In Comparative Example 11, the listed amount of nuclei 601, a polyamide bismaleimide prepolymer, in the specified amount of N-methylpyrrolidone dissolved at the temperature of 50 ° C or less, and gave a dark red pre polymer solution.

The prepolymer solutions prepared according to Examples 1-6 above and Comparative Examples 1-11 show analy-Io

table certain values that their component ratios, as well as other specific properties, as in Table 2 specified.

From the results given in Tables 1 and 2, it can be seen that Comparative Examples 1-11 are the prepolymer solution with advantageous component ratios, as they are specific for the present invention, not capable of producing, assuming that the reason

for in the incorrect combination of reaction temperature 25

and time lies.

Table 2 follows:

Table 2

6 \ l Certain proportions (%) in the resin content. *1

8 9 10 Il

Unreacted respondents links

• 30.0 40.0 35.1 36.2 34.0 39.5 48.0 20.5 42.0 44.1 37.0 40.0 46.0 80.2 44.0 39.5 35.2 56.5 53.3 61.2 57.2 62.4 55.5 49.0 66.0 51.0 45.9 53.5 53.1 47.6 17.9 49.8 53.3 53.0

links

with a Molecular weight from 40 1 to 15,000

5.5 6.7 3.7 6.6 3.6 5.0 3.0 13.5 7.0 10.0 9.5 6.9 6.4 1.9 6.2 7.2 11.8

with a

Molecular weight above 15,000 Molar ratio of bis-imide to diamine of unreacted reactants} «2

I 2.1 2.4 2.1 1.8 2.2 2.7 2.1 2.1 2.8 3.2 1.5 3.9 2.2 2.0 2.1 2.2 4.0

Gel formation time (min) at 160 ° C

I 14.0 14.5 15.3 12.9 14.0 15.7 17.2 6.5 10.0 9.0 7.5 15.2 16.7 21.3 16.5 13.5 12.0

,1:

viscosity

(ep), at 30 * 4: 1200 1420 1130 1520 900 1300 620 4900 1820 2100 2500 1450 660 «4 950 1300 1800

stability 0 0 Π 0 0 0 X 0 X X 0 X X X X 0 A. at 20 "C 0 0 0 0 0 0 X 0 X X 0 X X X X 0 A. at -5 * C

• 1: Ratio of peak areas, obtained from the GPC Chromaloyreimm, as already explained, * 2:! Determination by liquid chromatography, as already explained.

* 3: Stability, determined if the corresponding prepolymer solutions are included. the listed were left to stand, and determined by observing whether a puff phase was off the solution failed, the symbols in the table mean the following: 0 «. stable for 7 days and more; A "solid phase failed after 4 days" X ·. solid phase precipitated within 1 day (not for uniform impregnation of the substrate »suitable with the corresponding prepolymer solution)

* 4: occurrence of precipitation

to

10

> l>

Ca)

cn

cn

NJ CD

the following are now those using the above Prepregs available by reference explained on table 3.

5 surface-treated glass fabric with a specific gravity of 105g / m ^ was treated with each of the prepolymer solutions of Examples 1-5 above and Comparative Examples 2 and 11 are impregnated. The resulting resin-impregnated Glass fabric was then partially cured in a drying oven in such a way that a prepreg with a Resin content of 4 7-50% was obtained. The specific properties of each of the prepregs thus produced are in Table 3 listed, from which it can be seen that the prepreg according to the invention with the specific component ratio cannot be prepared using the prepolymers of the comparative examples.

20 25 30 35

Table ⁴

Example No. 7 8

10 11 Comparative Example No.
13 14 15 16

Conditions:
prepoly solution used (example no. in table 1) temperature ( ⁰ C)

150 140 155 140 130 2 '11

150 170 140 140

Certain proportions (%) in resin content * 1 Unreacted reactants

Compounds with a molecular weight of 400 to 15,000

Compounds with a molecular weight above 15,000

26.2 25.1 22.2 25.5 19.1 28.0 64.7 62.6 69.3 60.9 73.0 57.5

9.1 12.3 8.5 13.6 7.9 14.5 34.8 15.3 24.1 16.0 27.9

58.3 63.5 58.6 59.8 54.3

6.9 21.2 17.3 24.2 17.8

Gel time (sec .) at 170 °
350 C.
300 330 290 320 270 570 130 180 110 180 Melt viscosity
(poise) at 130 ° C * 2 970 1050 980 1000 960 1100 810 2050 1450 4500 1500 0.60 0.64 0.58 0.76 0.55 0.62 1.48 0.51 0.85 0.73 1.02 Volatile component ^
(180 ⁰ C, 20 min) |

* 1: Ratios of the peak areas obtained from the GPC chromatogram

as already explained.

* 2: Measured in a flow meter (flow tester) 2 ": Comparative Example 2 in Tables 1 and

U)

CO

cn

cn ho

CD

The explanation of laminate products obtainable from the above prepregs will now be given. Four square pieces measuring 12 by 12 cm ^ were placed at an angle of 45 ° to the
Longitudinal orientation of the glass fibers from each of the prepregs of Examples 10 and 11 and Comparative Examples 12, 14 and 15, listed in Table 3, cut out and then stacked between a pair of 1.6 mm thick sizing plates to continue between them at a temperature of 165 ° C at a pressure of 10 kg / cm ^ over 10 mi

Grooves to be further cured to produce a laminate. The resin flowability of each of the such produced laminates is listed in Table 4, where the resin flowability is the ratio of the weights (%) flowed out Resin of the prepreg during curing to weight of the

Shows 15 prepregs before curing.

Table 4

Example No. Comparative Example No.

J_3 1_4 J_5 Vl 18 12

Inset 7 10 11 12 ^ "14 *" 15 *
Prepreg (example no.)

Resin flow 19.2 16.4 22.3 35.6 9.1 3.7 ability (%)

Ti] TÄ] 15: Prepregs of the comparative examples in Table 3
25th

As can be seen from the table, the laminates of Examples 13, 14 and 15 are stated to be useful Resin content due to a suitable resin flowability of the The prepregs used also have a low dimensional variance based on their thickness compared to the Laminates of the comparative examples.

Table 5

at 16 game No 19th 20th relation 18th verc iieicn sDeis piei. wr. 24 7th 8th 18th 10 11th 12th 19th 20th 21 22nd 23 16 inserted 9 11th 13th 13th 14th 15th 16 Prepreg game no. in Table 3) 15th 15th 15th 15th 15th 35 Form printing 15th 35 15th 35 35 50 15th (kg / cm ² ) 0 0 0 0 0 0 Form character 0 0 X 0 0 0 X teristics * i 1.36 1.32 1.28 1.45 0.98 1.02 Cohesion 1.40 1.47 - 1.07 1.09 0.77 - force (kg / cm) 0.8 0.8 0.8 0.9 1.0 1.2 'Dimendonsva--
rianiu / rome) 0.9 1.3 - 1.3 1.3 1.6 -

* 1: Pas symbol 0 indicates that there are no voids or other surface defects
were observed; and

the symbol X indicates that this has been observed.

(It was made after removing the copper foils from both sides of the sample
observed)

Table 5 shows test results of laminates fabricated from the prepregs prepared as above.

Manufacture of double-sided printed circuits

Five sheets of 50 cm 50 cm square coupons were prepared from each of the prepregs of Examples 7 to 11 and Comparative Examples 12-16, and superposed to form a core. Each core was then placed with a pair of surface-treated copper foils on both sides between a pair of 1.6 mm thick sizing plates, heated to a temperature of 130 ° C. and immediately thereafter subjected to a pressure of 5 kg / cm 2 for 20 minutes
held on this condition.

Subsequently, each laminate was heated to a temperature of 170 ° C. at a pressure shown in Table 5 for 90 minutes and then cooled to room temperature while maintaining the pressure at the same pressure level to create a printed circuit with copper foil adhered to both sides of the same. The resulting printed Circuit was given a 120-minute post-curing treatment subjected to a temperature of 200 ° C and then converted into a circuit by conductive Lines were formed in the copper layer by a known etching method, and then with respect to investigated their shape characteristics as well as their cohesive forces, whereby this is the force that is required for this will remove a layer of copper foil from the core by a perpendicular tensile force acting on the surface of the layer is exercised, the results are shown in Table 5.

Manufacture of a multilayer printed circuit 35

25cm by 25cm square test panels obtained from each of the prepregs were ^{coated on each side with a 0.030515g / cm 2} (1oz / ft ² ) copper foil of the same size and processed under the same conditions as above, a first laminate with copper foil layers on both sides to build.

Then index holes were drilled in every 1st laminate with a distance of about 200 mm in one direction and precise measurements of the distance between the index holes were recorded. The copper foils on both sides of the 1st laminate were then removed using a known etching process and 2 layers of prepregs of the same type and dimension were placed on each surface of the 1st laminate, one 0.0305 g / cm ² (1oz / ft ² ) Equal size copper foils were placed on each surface of the newly built prepreg. The resulting laminate was cured at a pressure of 40 kg / cm ² and a temperature of 170 ° C for 90 minutes, followed by post-curing treatment at a temperature of 200 ° C for 120 minutes to give a final laminate product having copper layers on both sides. The outer copper foil layer or the newly applied layer was then mechanically attached to sections

__ removed the index holes in the original 25th

Copper foil corresponded to in turn the exact distance between the index holes after the shapes of the To measure the laminate product. The measurement result of the end products was matched with the corresponding measurement results that were previously with the 1st laminate compared to the dimensional variance of the product before and after placement additional conductive layers, the result being listed in Table 5.

From Table 5 it can be seen that Examples 16-20, which use the prepreg according to the invention and with one

- 3 "-

low pressure, have a larger holding force than the comparative examples and also a smaller one Dimensional variance show what certainly meets the requirements

,. of multilayer printed circuits.

It is now noteworthy that, although the invention Polyimide prepolymer composition is particularly suitable for the manufacture of the laminate products, as is of course them can be used as a molding material in wide electrical applications, for example the prepolymer, with Provided suitable filler material, are used to seal semiconductors, carriers for electrical modules of high mechanical Resilience and superior elasticity too

form to glue chips on their mounting base, and 15

to make pastes for making circuits.

When using the prepolymer according to the invention, the products obtainable therefrom can with a remarkable Resilience and a high degree of cohesion

at the same time equipped with good elastic behavior 20

will.

Claims (7)

Claims 1. Polyimide prepolymer composition, available from Vor condensation of Ν, Ν-bis-imides of unsaturated dicarboxylic acids of the general formula CO CO D N-A-N ^N cc / where D is a divalent organic radical that has a C-C double bond contains and A is a divalent organic radical with at least two carbon atoms, with (one) Diamine (s) of the general formula: H ₂ NB-NH ₂
where B is a divalent organic radical with no more than 30 carbon atoms and the bisimide to diamine molar ratio is between 1.2 and 50, characterized in that the composition is about 30-4056 not. reacted reactants, 53-65% components with a molecular weight of between 400 and 15,000 and 3.5 to 6.8% components with a molecular weight above 15,000. 2. Polyimide prepolymer composition according to claim 1, characterized in that the molar ratio of unreacted bis-imide to unreacted diamine is between 1.7 and 3.0. 3. Polyimide prepolymer composition, thereby marked -15 draws that the condensation at a Temperature below 95.degree. C., preferably between 60.degree. And 90.degree. C., is carried out. 4. Prepreg, produced by dissolving a polyimide prepoly-20 mer composition available from Precondensation of N, N ¹ -bis-imides of unsaturated dicarboxylic acids of the general formula CO / ⁰⁰ V. Ot ^ NA-KT J ^ ^D where D is a divalent organic radical that has a C-C double bond contains and A is a divalent organic radical having at least two carbon atoms, with diamines the general formula: H ₂ NB-NH ₂ 35 δ Δ 1
where B is a divalent organic radical with no more than 30 carbon atoms, and the molar ratio of bisimide to diamine is between 1.2 and 50, in a solvent, Applying the solution to a substrate and partial curing of the resin-containing substrate, ._ characterized in that the resin after curing about 18 to 28% unreacted reactants , 55-10% components with a molecular weight between 400 and 15,000 and 7-10% components with a molecular weight above 15 000 has. 5. prepreg according to claim 4, characterized in that the molar ratio of unreacted bis-imides to not reacted diamine is between 1.7 and 3.0. 6. A prepreg as claimed in one of claims 4 and 5, dadurc h, that the partial curing of the prepreg at a temperature below 95 ° C, preferably between 60 and 90 ° C, is carried out. 7. A method for producing a laminate, characterized in 25 by superimposing a predetermined number of prepregs according to any one of claims 4 to 6; Hang up of (a) metal foil (s) on one or both exposed surfaces of the prepreg stack and forming a laminate applying elevated temperature and pressure to achieve the 30th The prepregs are cured and the metal foil (s) are glued on cause.