DE10043205A1 - Epoxy resin mixture for production of composites, e.g. prepregs and laminates for printed circuit boards, contains special phosphorus-modified epoxy resin, dicyandiamide or aromatic amine and hardening accelerator - Google Patents

Abstract

An epoxy resin mixture for composite production containing (a) phosphorus-modified epoxy resin, (b) dicyandiamide and/or aromatic amine derivative and (c) a hardening accelerator, in which component (a) is obtained by reacting polyepoxide compounds with phosphinic, phosphonic and/or pyrophosphonic acids. An epoxy resin mixture for the production of composites contains (a) a phosphorus-modified epoxy resin with an epoxide value of 0.02-1 mol/100 g, obtained by reacting (A) polyepoxide compounds with at least 2 epoxide groups with (B) phosphinic, phosphonic or pyrophosphonic acids, (b) dicyandiamide and/or an aromatic amine of formula (I) or (II) as hardener [Image] [Image] X : H; Y : 1-3C alkyl; m, n : 0-4; (m+n) : 4; R : OH or NR1>R2>; R1>, R2>H or 1-3C alkyl, or one of these groups is H or 1-3C alkyl and the other is NR3>R4>; R3>, R4>H or 1-3C alkyl and (c) a hardening accelerator. Independent claims are also included for the following: (i) prepregs or composites based on inorganic or organic reinforcing materials (as fibres, non-wovens, woven fabric or sheet materials) and made with the above epoxy resin mixture; and (ii) printed circuit board material produced from woven glass fibre fabric and the epoxy resin mixture.

Description

The invention relates to an epoxy resin mixture, in particular one that is suitable for making prepregs.

Composite materials based on epoxy resins and anorga niche or organic reinforcement materials have in many areas of technology and daily life gained great importance. The reasons for this are, on the one hand, the right relatively easy and safe processing of the epoxy resins and on the other hand the good mechanical and chemical properties level of hardened epoxy resin molding, which is a match solution for different purposes and an advantageous one Use of the properties of all plants involved in the association fabrics allowed.

The processing of epoxy resins into composite materials follows advantageously over prepregs. For this purpose, anor ganic or organic reinforcement materials or Einla components in the form of fibers, nonwovens and fabrics or impregnated with the resin in the form of sheet materials. In the in most cases this happens with a solution of the resin in an easily evaporable or volatile solvent. The Prepregs obtained in the process must not be used after this process more sticky, but also not yet hardened, rather the resin matrix should only pre-polymerize state.

In addition, the prepregs must be sufficiently stable in storage. So is used, for example, for the production of printed circuit boards Storage stability of at least three months is required. at processing to composite materials must Prepregs also melt and rise when the temperature rises with the reinforcement materials or storage components as well as with the materials provided for the composite under  Connect pressure as firmly and permanently as possible, d. H. the ver wetted epoxy resin matrix must have a high interfacial adhesion the reinforcement materials or storage components so how to the materials to be connected, such as metallic, ke ramischen, mineral and organic materials, ausbil the.

In the hardened state, the composites produce genes rell high mechanical and thermal strength as well as chemi cal resistance and heat resistance or aging resistance required. For electrotechnical and electronics applications, there is a demand for permanently high e dielectric insulation properties and for special A variety of additional requirements to. For use as circuit board material are examples wise high dimensional stability over a wide temperature area, good adhesion to glass and copper, high upper surface resistance, low dielectric loss factor, gu machining behavior (punchability, drillability), low water absorption and high corrosion resistance required Lich.

Another requirement is that it be flame retardant. In Many areas come up to this demand - because of the danger endowing people and property - first priority at for example with construction materials for aircraft and automotive engineering and for public transportation. at electrotechnical and especially electronic applications is the flame resistance of circuit board materials - because of the high value of the electronic mounted on it Components - indispensable. To assess the burning behavior tens must therefore be one of the toughest material testing standards stand, namely the V-0 classification according to UL 94 V. At this test is a test specimen vertically at the bottom flamed with a defined flame. The sum of the focal times of 10 tests must not exceed 50 s. This Demand is difficult to meet, especially when thin  Wall thicknesses exist, as is the case in electronics is. The worldwide in technical use for FR4 laminates sensitive epoxy resin only meets these requirements because it - based on the resin - approx. 30 to 40% core brominated aromati contains epoxy components, d. H. approx. 17 to 21% bromine. For other purposes, the concentration is comparatively high used on halogen compounds and often still with an Timon trioxide combined as a synergist. The problem with These connections are that on the one hand are excellent as flame retardants, on the other hand but also have very questionable properties. So it says Antimony trioxide on the list of carcinogenic chemicals lien, and aromatic bromine compounds split in the ther not only mix decomposition bromine radicals and hydrogen bromide from which lead to severe corrosion, but at the decomposition tion in the presence of oxygen can in particular highly brominated aromatics also the highly toxic polybromodibs Form zofurans and polybromodibenzodioxins. substantial The disposal of bromhalti also presents difficulties against old materials.

There was no lack of attempts, the brominated flame Protect with less problematic substances put. For example, fillers with extinguishing gas were such as alumina hydrates ("J. Fire and Flammability", Vol. 3 (1972), pages 51 ff., Basic aluminum carbonates ("Plastics Engineering", Vol. 32 (1976), pages 41 ff.) And Magnesium hydroxides (EP-OS 0 243 201), as well as glazing fillers fabrics such as Borate ("Modern Plastics", Vol. 47 (1970), No. 6, Pages 140 ff.) And phosphates (US Pat. Nos. 2,766,139 and 3,398,019), proposed. However, all of these fillers are liable Disadvantage that they the mechanical, chemical and elect The physical properties of the composite materials are sometimes increased worsen. They also require special, mostly more complex processing techniques because they are used for sedimentation incline and increase the viscosity of the filled resin system.  

It is also the flame retardant effectiveness of red Phosphorus has been described (GB-PS 1 112 139), if necessary in combination with finely divided silicon dioxide or aluminum peroxide hydrate (U.S. Patent 3,373,135). Thereby materials receive their use for electrotechnical and electronics cal purposes - because of the emergence in the presence of moisture phosphoric acid and the associated corrosion - is restricted. Organic phosphorus has also been added compounds such as phosphoric acid esters, phosphonic acid esters and Phosphines, proposed as flame retardant additives (see: W.C. Kuryla and A.J. Papa "Flame Retardancy of Polymeric Ma terials, vol. 1, pages 24 to 38 and 52 to 61, Marcel Dec Ker Inc., New York, 1973). Because these connections for their "softening" properties are known and therefore as Plasticizers for polymers used on a large scale worldwide are (GB-PS 10794), this alternative is also little promising.

For the flame retardant setting of epoxy resins can also organic phosphorus compounds, such as those containing epoxy groups Phosphorus compounds, which are used in the epoxy resin network can be climbed. So are from EP-OS 0 384 940 Epoxidharzmi known, the commercially available epoxy resin, the aromatic polyamine 1,3,5-tris (3-amino-4-alkylphenyl) - 2,4,6-trioxo-hexahydrotriazine and one containing epoxy groups Phosphorus compound based on glycidyl phosphate, Glyci contain dylphosphonate or glycidylphosphinate. With suchi epoxy resin mixtures can be - without halogen addition - flame-retardant laminates or UL 94 V-0 classifiable Manufacture composites that have a glass transition temperature have a temperature of <200 ° C. In addition, this epoxy Resin mixtures comparable to those in use Process FR4 materials.

US Pat. No. 5,587,243 discloses epoxy resin mixtures Manufacture of prepregs and composites known also the aromatic polyamine 1,3,5-tris (3-amino-4-  alkylphenyl) -2,4,6-trioxo-hexahydrotriazine (PAIC) as hardener and contain a phosphorus modified epoxy resin, which by Implementation of polyepoxide compounds with at least two Epo oxide groups per molecule and at least one compound the group of phosphinic and / or phosphonic anhydrides was asked. Because anhydrides are difficult to manufacture and EP 0 689 559 epoxy resin mixtures were half comparatively expensive for the production of prepregs and ver used materials that, in addition to this aromatic bottom lyamin contain a phosphorus-modified epoxy resin that by reacting polyepoxide compounds with at least two epoxy groups per molecule with at least one verb from the group of phosphinic acids, phosphonic acids, Py rophosphonic acids and phosphonic acid half-esters was produced de. Both patents use the known fact that the aromatic polyamine essential to the flame retardancy of the Laminates contributes so that a phosphorus content in the laminate of 2.5 to 3.0% is sufficient to achieve a UL 94 V-0 rating pass. However, laminates made in this way have the disadvantage that because of the polar structure and the ho hen share of the aromatic hardener PAIC relatively much water record so that after each manufacturing step, the one includes thermal stress <100 ° C, can be dried have to.

It has therefore been tried without the aminic hardener Get along and rely on the use of phosphine and Phosphonic anhydrides, which are more expensive than those in EP 0689 559 phosphonic and phosphinic acids used are to be restricted ken. In the patents EP 0 779 905 and EP 0 779 906 are epoxy resin mixtures for the production of prepregs and Composites described next to a commercial Epoxy resin containing a phosphorus-modified polyepoxide, that by reacting polyepoxide compounds with at least two epoxy groups per molecule and at least one verb from the group of phosphinic anhydrides, phosphonic acid reanhydride or phosphonic acid half-ester was produced and  Dicyandiamide and / or an aminobenzoic acid derivative as hardener (EP 0 779 905) or an aromatic group containing amino groups Sulfonic acid amide or hydrazide as hardener (EP 0 779 906) ent hold.

Laminates made from these epoxy resin mixtures are required approx. 3 to 3.5% phosphorus in the epoxy resin matrix approx. 1% more phosphorus than when using PAIC as hardener, to achieve flame retardancy according to UL 94 V-0, which is the thesis supports that PAIC contributes significantly to flame retardancy. These high phosphorus concentrations have proven to be excellent spoke problematic, since they the shelf life of the mo differentiated epoxy resins and those made from them Prepregs affect and the water absorption of the laminates increase significantly so that this before each thermal Belas must be subjected to drying. Except there is known to be comparative to phosphorus compounds are expensive and therefore increase the laminate price in a way hen that these are only partially suitable for technical use Question come.

Printed circuit boards are the basis for the production of electro African PCBs. They serve the most varied electronic and microelectronic components to connect to electronic circuits. In doing so the components - using complex, highly automated loading packaging processes - by gluing or soldering with the Lei terplatte connected. Also with the assembly of printed circuit boards there is a trend towards ever more rational manufacturing methods. Therefore, IR reflow soldering is increasingly used in SMD technology applied that the other soldering processes in the future going to replace. But only laminates with low water absorption and very good interlaminar adhesion survive IR Soldering processes without destruction by delamination. To the mind Elaborate conditioning processes were used to avoid this danger proposed (see: "Galvanotechnik", Vol. 84 (1993), Pages 3865 to 3870).  

The so-called so-called are particularly critical in this regard Multilayer circuit boards (ML), which are a large part of today's days of printed circuit boards. This circuit board ten contain a large number of conductor levels, which are defined by Epo xid resin composites are spaced apart and isolated. The trend in ML technology is now increasing number of conductor levels; so multilayer Printed circuit boards with more than 20 conductor levels. There one too high total thickness of these circuit boards from technical Reasons must be avoided, the distance between the Ladder levels are getting lower and therefore the interlaminar haf problem with ML laminates. With IR soldering are also particularly ho on this type of circuit boards he requirements regarding the resistance of the solder bath provides. Excessive water absorption affects soldering Resistance to the bath, as the absorbed water at temperature <100 ° C evaporates and creates an internal pressure that can lead to delamination.

The object of the invention is a technically simple and there to be specified with inexpensive epoxy resin mixture, which are comparable to those in technical use Processable epoxy resins and for the production of prepregs and laminates is suitable, which - without halogen addition - flame-retardant, d. H. Moldable materials classified according to UL 94 V-0 result, which are due to a low water absorption without Process intermediate drying to build up multilayers and have sufficient interlaminar adhesion.

The technical problem is solved according to the invention in that the epoxy resin mixture comprises the following components

• - A phosphorus-modified epoxy resin with an epoxy value of 0.02 to 1 mol / 100 g, obtainable by reacting
  • A) with polyepoxide compounds with at least two epoxy groups per molecule
  • B) at least one compound from the group of phosphinic acids, phosphonic acids and pyrophosphonic acids,
• - Dicyandiamide and / or an aromatic amine of structure I and / or structure II as a hardener
  the following applies:
  X is an H atom and Y is an alkyl group with 1 to 3 C atoms and m or n is an integer from 0 to 4 with the proviso m + n = 4,
  R ⁴ is an OH or an NR ¹ R ² group and the radicals R ¹ and R ² - independently of one another - have an H atom, an alkyl group with 1 to 3 C atoms or one of the radicals R ¹ and R ² this meaning and the other radical is an NR ³ R ⁴ group with R ³ or R ⁴ = H or alkyl with 1 to 3 C atoms,
• - a hardening accelerator.

The phosphorus-modified epoxy resins are produced by reacting commercially available polyepoxy resins (polyglycidyl resins) with the following phosphorus compounds:

• - Phosphonic acids: Phosphonic acids with alkyl residues, preferred wise with 1 to 6 carbon atoms, or with aryl radicals,  especially benzene phosphonic acid;
• - Phosphinic acids: dialkylphosphinic acids, preferably with 1 up to 6 carbon atoms in the alkyl radical, alkylarylphosphine acids or diarylphosphinic acids;
• Pyrophosphonic acids: Compounds are preferably used gene to which the above-mentioned phosphonic acids green de lie; Pyrophosphonic acids are caused by dehydration sation of phosphonic acids by known methods (see on this: Houben-Weyl, Methods of Organic Chemistry, 4. Edition, Vol. XII / 1 (1963), page 606).

In general, both aliphatic and aromatic glycidyl compounds and mixtures thereof can be used to prepare the phosphorus-modified epoxy resins. Before are added bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, polyglycidyl ether of phenol / formaldehyde and cresol / formaldehyde novolaks, diglycidyl ester of phthalic, tetrahydrophthalic, isophthalic and terephthalic acid such as mixtures of these epoxy resins. Other polyepoxides that can be used are, for example, hydrogenated bisphenol A and bisphenol F diglycidyl ether, hydantoin epoxy resins, triglycidyl isocyanurate, triglycidyl p-aminophenol, tetragly cidyl diaminodiphenyl methane, tetraglycidyl diaminodethenidoxyphenyl (4) ethylenediaminophenyl (4) ethylenediaminophenylphenyl (4-olefin), tetraglycidyl diaminodethenidoxyphenyl (4) Epoxy resins and epoxies described in the "Handbook of Epoxy Resins" by Henry Lee and Kris Neville, McGraw-Hill Book Company 1967, and in the monograph by Henry Lee "Epoxy Resins", American Chemical Society 1970. The average molecular weight M _{n of} the polyepoxide compounds is generally 150 to 4000, preferably 300 to 1800. The phosphorus-modified epoxy resin is present in the epoxy resin mixture in a total content of approximately 30 to 98% by mass.

Depending on the choice of the initial molar ratio phosphorus compound Phosphorus-modified epoxy resins can be used to form epoxy resins with different epoxy content and therefore different manufacture phosphorus content. For the production of lamina Phosphorus-modified epoxy resins are preferred with an average of two epoxy groups used per molecule. space the initial molar ratio is generally chosen so that the order Settlement products contain 5 to 10% by mass of phosphorus.

The epoxy resin mixture can also be a phosphorus-free one contain aromatic and / or heterocyclic epoxy resin; This epoxy resin can also be a cycloaliphatic epoxy resin be mixed in. In general, up to 80% by mass of the phosphorus-modified epoxy resin by phosphorus-free epo xid resin to be replaced, this corresponds approximately to a maximum 70% by mass of phosphorus-free epoxy resin in the ge whole epoxy resin mixture.

The addition of phosphorus-free epoxy resin is used for education development of certain properties of those according to the invention Laminates produced by epoxy resin mixtures. The mix ratio of the two components is determined by the Demand for flame retardancy according to UL 94 V-0 at 1.6 mm Thickness. This means that the phosphorus-free compo nente may only be admixed to an extent that the Ge velvet mixture still contains so much phosphorus that the said Requirement is met. For epoxy resins with high phosphorus content can therefore more phosphorus-free epoxy resin than with low phosphorus epoxy resins. The Total phosphorus content of the epoxy resin mixture should be 2 to 5% by mass, preferably 2.5 to 3.5%.

Both as an additional phosphorus-free polyepoxy resin and also for the production of phosphorus-modified epoxy resins The following polyglycidyl compounds are particularly suitable: aromatic polyglycidyl ethers, such as bisphenol A diglycidyl ether, bisphenol F diglycidyl ether and bisphenol S diglycidyl ether, polyglycidyl ether of phenol / formaldehyde  and cresol / formaldehyde resins, resorcinol diglycidyl ether, Tetrakis (p-glycidylphenyl) ethane, di- or polyglycidyl ester of phthalic, isophthalic and terephthalic acid and of trimel lithic acid, N-glycidyl compounds of aromatic amines and heterocyclic nitrogen bases, such as N, N-diglycidylaniline, N, N, O-triglycidyl-p-aminophenol, triglycidyl isocyanurate and N, N, N ', N'-tetraglycidyl-bis (p-aminophenyl) methane, hydane toin epoxy resins and uracil epoxy resins as well as di- and buttocks lyglycidyl compounds of polyhydric aliphatic alcohol len, such as 1,4-butanediol, trimethylolpropane and polyalkylene glycol kolen. Furthermore, oxazolidinone modified Epo xid resins suitable. Such connections are already be known (see: "Angew. Makromol. Chem.", Vol. 44 (1975), pages 151 to 163, and U.S. Patent 3,334,110); be an example of this the reaction product of bisphenol A diglycidyl ether with Diphenylmethane diisocyanate (in the presence of a suitable Be accelerator) called. The polyepoxy resins can be used in the Production of the phosphorus-modified epoxy resin individually or in a mixture. Preferred is the polyepoxy resin an epoxidized novolak was used.

The following compounds in particular are used as the phosphorus component for the preparation of the phosphorus-modified epoxy resins:

• - phosphonic acids: methanephosphonic acid, ethanephosphonic acid, Propanephosphonic acid, hexanephosphonic acid and ben zolphosphonsäure;
• - Phosphinic acids: dimethylphosphinic acid, methyl ethylphosphinic acid, diethylphosphinic acid, dipro pylphosphinic acid, ethylphenylphosphinic acid and diphe nylphosphinsäure;
• - Pyrophosphonic acids: methane pyrophosphonic acid, propane py rophosphonic acid and butane pyrophosphonic acid.

The phosphorus-modified epoxy resins are prepared in such a way that the polyepoxide compounds are reacted with the acids containing phosphorus, preferably in an inert solvent or diluent or, if the reaction is adapted, also in bulk. The phosphorus-modified epoxy resins have an average molecular weight M _n up to 10,000; preferably M _{N is} 200 to 5000 and in particular 400 to 2000.

If solvents or diluents are used, they are aprotic and preferably have a polar character. Examples include N-methylpyrrolidone; Dimethylformamide; Ethers, such as diethyl ether, tetrahydrofuran, dioxane, ethylene glycol monoether and diether, propylene glycol monoether and diether and butylene glycol monoether and die, the alcohol component of the mono- or diether of monoalcohols having an optionally branched alkyl radical of 1 to 6 hydrocarbon atoms derived; Ketones such as acetone, methyl ethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone and cyclohexanone; Esters such as ethyl acetate, butyl acetate, ethyl glycol acetate and methoxypropyl acetate; halogenated hydrocarbons; (cyclo) aliphatic and / or aromatic hydrocarbons, such as hexane, heptane, cyclohexane, toluene and the various xylenes; aromatic solvents in the boiling range of approx. 150 to 180 ° C (higher-boiling mineral oil fractions, such as Solvesso ^R ). The solvents can be used individually or in a mixture. The implementation tongues run at -20 to 130 ° C, preferably at 20 to 90 ° C.

The equivalent ratio can be used for the production of prepregs nis between used epoxy function and used Amine hydrogen function in the epoxy resin according to the invention mixtures be 1: 0.2 to 1: 1.1.

The epoxy resin mixtures according to the invention can also be accelerators known to be used in the hardening of  Epoxy resins play an important role. Usually who the tertiary amines or imidazoles used. Suitable as amines For example, tetramethylethylenediamine, dimethyloctyla min, dimethylaminoethanol, dimethylbenzylamine, 2,4,6- Tris (dimethylaminomethyl) phenol, N, N'- Tetramethyldiaminodiphenylmethane, N, N'-dimethylpiperazine, N- Methylmorpholine, N-methylpiperidine, N-ethylpyrrolidine, 1,4- Diazabicyclo (2,2,2) octane and quinolines. Suitable imidazoles are, for example, 1-methylimidazole, 2-methylimidazole, 1,2- Dimethylimidazole, 1,2,4,5-tetramethylimidazole, 2-ethyl-4- methylimidazole, 1-cyanoethyl-2-phenylimidazole and 1- (4,6- Diamino-s-triazinyl-2-ethyl) -2-phenylimidazole. The acceleration niger are in a concentration of 0.01 to 2 mass%, preferably 0.05 to 1%, each based on the epoxy resin mixture.

The individual components are used for prepreg production separates or together in inexpensive solvents, such as Acetone, methyl ethyl ketone, ethyl acetate, methoxyethanol, di methylformamide and toluene, or in mixtures of such Lö Solvent dissolved, optionally combined into a solution and processed on common impregnation systems, d. H. to the Soaking fibers made of inorganic or organic matter alien, such as glass, metal, minerals, carbon, aramid, po lyphenylene sulfide and cellulose, as well as manufactured therefrom fabrics or fleeces or for coating surfaces substances, such as foils made of metals or plastics puts. If necessary, the impregnation solutions can also be white Other flame-retardant halogen-free additives contain, some of which are homogeneously dissolved or dispersed can. Such additives can, for example, Melamincyanu rate, melamine phosphates, powdered polyetherimide, polye thersulfone and polyimide.

Glass fabric is predominantly used to manufacture prepregs for printed circuit board technology. For multilayer printed circuit boards, prepregs made of glass fabric types with a basis weight of 25 to 200 g / m ² are used in particular. With impregnation solutions of the type mentioned above, prepregs with low basis weights can also be produced as required. The impregnated or coated reinforcing materials or intercalation components are dried at elevated temperature, the solvent being removed on the one hand and the impregnating resin being prepolymerized on the other hand. Overall, this results in an extremely favorable ratio of effort to achievable properties.

The coatings and prepregs obtained are non-adhesive and at room temperature for three months and more stable in storage, d. H. they have an adequate storage capacity bility. They can be used at temperatures up to 220 ° C Pressing composite materials that are characterized by high glass transition temperatures of ≧ 180 ° C and inherent heavy flammability. Are used as storage material for example glass fabric with a mass fraction of 60 to 62 %, based on the laminate, is used, the burning test UL 94V - without the addition of halogen compounds or other flame retardant additives, even with test specimens pern with a wall thickness of 1.6 mm or even 0.8 mm - with a safe V-0 rating. It proves it is particularly advantageous that no corrosive or be particularly toxic fission products are formed and the Smoke development compared to other polymer materials, especially to bromine-containing epoxy resin molding materials, strong is reduced.

The cured composites also stand out through a constant over a wide temperature range small coefficient of thermal expansion and high Chemical resistance, corrosion resistance, low Water absorption and very good electrical property values out. Liability for the reinforcing and connecting measures materials is excellent. When using reinforcement materials  of the type mentioned are prepregs for mechanical receive heavy-duty construction materials. This Construction materials are suitable for applications, for example in mechanical engineering, vehicle construction, and flight technology and in electrical engineering, for example in the form of Prepregs for the manufacture of printed circuit boards, in particular also for the production of multilayer circuits.

Of particular advantage for the use as printed circuit boards material is the high adhesive strength of conductor tracks Copper, the high delamination resistance and an excellent Machinability, for example when drilling Via holes in it show that perfect Boh with little drill wear. In order to can materials that using the invention ß epoxy resin mixtures are produced, in particular multilayer printed circuit boards in which thin cores with <100 µm, Thickness are used, more secure or less expensive be manufactured.

The invention is based on the surprising finding that according to Addition of phosphinic and phosphonic acids to polyepoxide converters bonds by treatment with alkali carbonates such as sodium carbonate or potassium carbonate, stable, acid-free phosphormo Distinguished epoxy resins are obtained with the comparative low concentrations (e.g. with 2.5-3.0% Phos phor, based on the entire resin mixture) with dicyandiamide or the other hardeners that can be used according to the invention without Use of PAIC flame retardant laminates result in a Achieve UL 94 V-0 rating.

The advantages of this finding are that

• - the water absorption of the laminates is significantly reduced, the high pressure cooker test is passed and an intermediate not drying the material during processing is required,  
• - The interlaminar adhesion and the adhesion to the copper indicate is improved,
• - An extremely inexpensive solution is made possible.

The epoxy resin system according to the invention also results in Verwen dicyandiamide, e.g. B. in an amount of 1 to 10 mas se%, as hardener good results in the high-pressure cooker test. This could be due to the moderate results with those with Phosphonic and phosphinic anhydrides modified epoxy resins in the patents EP 0 779 905 and EP 0 779 906 have not been expected.

Based on exemplary embodiments, the invention is intended to forth be explained.

Production of the phosphorus-modified epoxy resins example 1 Production of the phosphinic acid-modified Epo oxide resin MEPS / EP resin

400 parts by mass (MT) of an epoxidized novolak (epoxy value: 0.56 mol / 100 g, average functionality: 2.6), dissolved in 170 MT Methyl ethyl ketone, be with 100 MT ethylmethyl added phosphinic acid. The solution is an oil for 60 min bath temperature of 100 ° C stirred under reflux. After the Ab cool the solution, add 40 MT sodium carbonate, Stir for another 12 hours and then filter the fes components. The implementation product has an epo xid value of 40 mol / 100 g, which after a short storage period stabilized to a value of 0.22 mol / 100 g. The phosphor content of the reaction product 5.9%.

Example 2 Production of the phosphonic acid-modified Epo oxide resin EPS / EP resin

400 parts by weight (MT) of a bisphenol-F-diglycidyl ether (Epo xid value: 0.61 mol / 100 g), dissolved in 250 MT methyl ethyl ketone, are mixed with 92 MT ethanephosphonic acid. The solution will be 60 minutes at an oil bath temperature of 100 ° C under reflux touched. After the solution has cooled, 40 parts by mass are added Add sodium carbonate, stir for a further 12 hours and filter then remove the solid components. The implementation pro product has an epoxy value of 0.38 mol / 100 g, which is after a short storage time to a value of 0.20 mol / 100 g sta stabilizes. The phosphorus content of the reaction product be carries 5.4%.

Example 3 Preparation of a phosphinic acid modified Epo xidharzes without subsequent addition of sodium carbonate, ana log Example 1 of EP 0 689 559 B1

400 parts by mass (MT) of an epoxidized novolak (epoxy value: 0.56 mol / 100 g, average functionality: 3.6), dissolved in 170 MT Methyl ethyl ketone, be with 50 MT ethylmethyl added phosphinic acid. The solution is an oil for 60 min bath temperature of 100 ° C stirred under reflux. After short Storage time, the reaction product has an epoxy value of 0.40 mol / 100 g. The phosphorus content of the reaction product tes is 3.2%.

The phosphorus-modified epoxy resins prepared in Examples 1-3 are examined for their stability at room temperature. Fig. 1 shows the result. While the epoxy value of the epoxy resins produced in Examples 1 and 2 remains stable or only decreases slightly, the epoxy value of the epoxy resin produced in Example 3 is reduced by almost 50% within 12 weeks.

Fig. 1

Stability of the epoxy resins prepared in Examples 1-3 at room temperature

Manufacture of prepregs Examples 4 and 5

A solution of A parts by mass (MT) dicyandiamide (Dicy) - in J MT dimethylformamide (DMF) - is mixed with a solution of D (1) MT of the phosphorus-modified epoxy resin (MEPS / EP resin) described in Example 1 (epoxy value: 0 , 22 mol / 100 g; phosphorus content: 5.9%), obtained from an epoxidized novolak (epoxy value: 0.56 mol / 100 g; average functionality: 3.6) and methylethylphosphinic acid, in G MT methyl ethyl ketone (MEK ) and I MT ethyl acetate (EA) added; E MT 2-methylimidazole (MeIM) is then added to the resin solution, and F (1) MT of an epoxidized novolake (epoxy value: 0.56 mol / 100 g; average functionality: 3.6; EP resin 1) or F (2) MT of a bisphenol A diglycidyl ether (EP resin 2) was added to obtain a phosphorus content in the resin matrix of 2.5%. With the resulting impregnation resin solution, which is then mixed with H MT DMF to set the correct viscosity, glass fabrics (glass fabric type 7628; basis weight: 197 g / m ² ) are continuously impregnated using a laboratory impregnation system and in a vertical drying system at temperatures from 50 to Dried 160 ° C. Prepregs produced in this way are tack-free. The composition of the impregnation resin solution and the properties of the prepregs can be found in Table 1.

Example 6

A solution of A parts by mass (MT) of dicyandiamide (Dicy) - in J MT of dimethylformamide (DMF) - is mixed with a solution of D (2) MT of the epoxidized novolak in Example 2 (epoxy value: 0.56 mol / 100 g ; Medium functionality: 3.6) and E thanphosphonic acid produced phosphorus-modified epoxy resin (EPS / EP resin) (epoxy value: 0.24 mol / 100 g; phosphorus content: 5.4%) in G MT methyl ethyl ketone (MEK) and I. MT ethyl acetate (EA) added; F (3) MT bisphenol-F-diglycidyl ether is then added to the resin solution in order to obtain a phosphorus content of 2.5% in the resin matrix. With the impregnating resin solution obtained, which is mixed with H MT DMF to set the correct viscosity, glass fabrics (glass fabric type 7628; basis weight: 197 g / m ² ) are continuously impregnated in a laboratory impregnation system and in a vertical drying system at temperatures from 50 to Dried 160 ° C. Prepregs produced in this way are tack-free. The composition of the impregnation resin solution and the properties of the prepregs can be found in Table 1.

Examples 7 and 8

The procedure is as in Examples 4 and 5. However, instead of dicyandiamide with B MT sulfanilamide (SAM) in J MT dimethylformamide (DMF), the impregnating resin solution is added. The resulting impregnation resin solution, which is then mixed with H MT DMF to adjust the correct viscosity, is used to continuously impregnate glass fabrics (glass fabric type 7628; basis weight: 197 g / m ² ) using a laboratory impregnation system and in a vertical drying system at temperatures from 50 to 160 ° C dried. Prepregs made in this way are tack-free. The composition of the impregnating resin solution and the properties of the prepregs can be found in Table 1.

Example 9

The procedure is as in Example 6. However, the impregnating resin solution is mixed with B MT sulfanilamide (SAM) in J MT dimethylformamide (DMF) instead of dicyandiamide. With the resulting impregnation resin solution, which is then mixed with H MT DMF to adjust the correct viscosity, glass fabrics (glass fabric type 7628; basis weight: 197 g / m ² ) are continuously impregnated by means of a laboratory impregnation system and in a vertical drying system at temperatures of 50 dried up to 160 ° C. Prepregs produced in this way are tack-free. The composition of the impregnating resin solution and the properties of the prepregs are shown in Table 1.

Example 10

The procedure is as in Examples 4 and 5. However, a mixture of A mass parts (MT) dicyandiamide with B MT sulfanilamide (SAM) in J MT dimethylformamide (DMF) is added to the impregnating resin solution. With the impregnation resin solution obtained, glass fabrics (glass fabric type 7628; basis weight: 197 g / m ² ) are continuously impregnated by means of a laboratory impregnation system and dried in a vertical drying system at temperatures from 50 to 160 ° C. The prepregs made by art are non-sticky. The composition of the impregnation resin solution and the properties of the prepregs are shown in Table 1.

Examples 11 (Comparative example 3 from EP 0 689 559)

A solution of 75 parts by weight (MT) of the reaction product prepared in Example 3 (epoxy value: 0.40 mol / 100 g) in 60 MT of methyl ethyl ketone is mixed with a solution of 25 MT of polyamino aryl isocyanurate (PAIC) in J MT of dimethylformamide (DMF), added. Further processing is carried out analogously to Examples 4 and 5. With the impregnating resin solution obtained in this way, glass fabrics (glass fabric type 7628; basis weight: 197 g / m ² ) are continuously impregnated by means of a laboratory impregnation system and in a vertical drying system at temperatures from 50 to 160 ° C dried. Prepregs produced in this way are tack-free. The composition of the impregnating resin solution and the properties of the prepregs are shown in Table 1.

Example 12 (Comparative example 1 from EP 0 779 905)

A solution of A parts by mass (MT) dicyandiamide (Dicy) - in J MT dimethylformamide (DMF) - is mixed with a solution of D (3) MT of a phosphorus-modified epoxy resin (EPS / EP resin) in the form of a reaction product (epoxy value: 0, 32 mol / 100 g; phosphorus content: 3.8%) from an epoxidized novolak (epoxy value: 0.56 mol / 100 g; average functionality: 3.6) and propanephosphonic anhydride in G MT methyl ethyl ketone (MEK) and I MT ethyl acetate ( EA) offset; E MT 2-methylimidazole is then added to the resin solution. Glass fabrics (glass fabric type 7628; basis weight: 197 g / m ² ) are continuously impregnated with the impregnating resin solution obtained by means of a laboratory impregnation system and dried in a vertical drying system at temperatures of 50 to 160 ° C. Prepregs produced in this way are tack-free. The composition of the impregnation resin solution and the properties of the prepregs are shown in Table 1.

Example 13 (Comparative example 7 from EP 0 779 905)

The procedure is as in Example 12, the impregnation resin solution is - instead of A MT dicyandiamide (Di cy) - with B (2) MT 4-aminobenzoic acid (ABS), dissolved in J MT Dimethylformamide (DMF) added. In addition, no hardening tion accelerator (E) added. The composition of the Im resin solution and the properties of the prepregs Table 1.

The prepregs produced in Examples 4, 7 and 11 are examined for their stability by storage at room temperature. Fig. 2 shows the result. While the remaining gel time of the prepregs produced in Examples 4 and 7 remains stable or only decreases slightly, the remaining gel time of the prepregs produced in the comparative example (Example 11 with PAIC hardener) is reduced by more than 50% within 12 weeks. The remaining gelling time remaining in this example is therefore completely inadequate. In example 12 (comparative example from EP 0 779 905) with 3.6%, a comparatively large amount of phosphorus is required in order to achieve the required flame retardancy. In example 13 (comparative example from EP 0 779 905) prepregs are obtained which do not achieve the prescribed shelf life of 3 months.

Table 1

Composition of the impregnation resin solutions

Fig. 2

Stability of the prepregs produced in Examples 4, 7 and 11

Production and testing of laminates Examples 13 to 23

Eight of the prepregs produced according to Examples 1 to 7 (glass fabric type 7628; basis weight: 197 g / m ² ), laminated on both sides with a 35 μm Cu foil, are pressed in a press at 175 ° C. and 20 bar. The 1.5 to 1.6 mm thick laminates are removed from the press after 40 minutes and then post-annealed at 175 ° C. for 2 hours. The glass transition temperature Tg, the flammability according to UL 94 V, the adhesive strength of the copper foil, the measuring test, the high-pressure cooker test and the resistance to the solder bath are measured on the bodies obtained in this way - by means of dynamic mechanical analysis (DMTA) certainly. The values obtained are shown in Table 2.

The tests carried out on the laminates proceed as follows:

• - Heat resistance on the solder bath
  The test is carried out in accordance with DIN IEC 249 Part 1, Section 3.7, using a solder bath in accordance with Section 3.7.2.3. Test specimens of size 25 mm × 100 mm are to be used, which are placed with the copper side on the solder bath. There must be no delamination and no formation of measlings, stains or blisters under the lamination.
• - Adhesion of the copper cladding
  A 25 mm wide and 100 mm long strip of copper foil is detached from the glass hard tissue over a length of 20 mm and pulled off vertically by means of a suitable device at a speed of 50 mm / min. The force F (N) required for this is measured.
• - The water absorption was measured according to MIL-P-13848 G carried out.
• - Examination of interlaminar liability
  A 25 mm wide and 100 mm long strip of the uppermost glass hard fabric layer is detached over a 20 mm length from the next glass hard fabric layer underneath and peeled off vertically by means of a suitable device with a pull-off speed of 50 mm / min. The force F (N) required for this is measured.
• - Measing test
  The test is carried out on test specimens measuring 20 mm × 100 mm without copper cladding. The test specimens are immersed in a LT26 solution at a temperature of 65 ° C. (composition: 850 ml deionized H ₂ O, 50 ml HCl pa, 100 g SnCl ₂ .2H ₂ O, 50 g thiourea), rinsed with running water and then placed in boiling water for 20 min. After air drying the sample (2 to 3 min), it is immersed in a 260 ° C solder bath for 10 s. The laminate must not delaminate.

Properties of the laminates

Table 2

Example 22 (comparative example from EP 0 779 905) is used with the prepregs made from the impregnating resin solution 12 neither the required solder bath resistance nor the high Pressure cooker test passed.

Claims (10)

1. Epoxy resin mixture for producing a composite material, characterized in that it comprises the following components:

• - A phosphorus-modified epoxy resin with an epoxy value of 0.02 to 1 mol / 100 g, obtainable by reacting
  • A) with polyepoxide compounds with at least two epoxy groups per molecule
  • B) at least one compound from the group of phosphinic acids, phosphonic acids and pyrophosphonic acids,
• - Dicyandiamide and / or an aromatic amine of structure I and / or structure II as a hardener
  the following applies:
  X is an H atom and Y is an alkyl group with 1 to 3 C atoms and m or n is an integer from 0 to 4 with the proviso m + n = 4,
  R is an OH or an NR ¹ R ² group and the radicals R ¹ and R ² - independently of one another - have an H atom, an alkyl group with 1 to 3 C atoms or one of the radicals R ¹ and R ² has them Be meaning and the other radical is an NR ³ R ⁴ group with R ³ or R ⁴ = H or alkyl having 1 to 3 carbon atoms,
• - a hardening accelerator.

2. Epoxy resin mixture according to claim 1, characterized net that it comprises a phosphorus-free epoxy resin. 3. epoxy resin mixture according to claim 1 or 2, characterized records that the phosphorus-free epoxy resin aromatic, he comprises terocyclic and / or cycloaliphatic components. 4. epoxy resin mixture according to one of the preceding claims, characterized in that as a phosphorus-modified epoxy resin an aromatic and / or an aliphatic glycidylver binding is used. 5. epoxy resin mixture according to one of the preceding claims, characterized in that the proportion of phosphorus modifi decorated epoxy resin in the total mixture between 30-98 wt .-% lies. 6. epoxy resin mixture according to one of the preceding claims, characterized in that a proportion of phosphorus-free E epoxy resin of up to 70 wt .-% is included. 7. Epoxy resin according to one of the preceding claims, characterized characterized in that the total phosphorus content between 2 is up to 5% by weight. 8. Epoxy resin according to one of the preceding claims, characterized characterized in that the total phosphorus content between 2.5 and 3.5 wt .-% is. 9. Prepreg or composite material based on inorganic or organic reinforcement materials in the form of Fibers, nonwovens or fabrics or fabrics are produced from an epoxy resin mixture according to one or more of the An sayings 1 to 8.   10. PCB material made of prepregs made of glass fiber fabric and an epoxy resin mixture according to one or more reren of claims 1 to 8.