DD292626A5 - METHOD FOR CONTINUOUS MANUFACTURE OF COPPER-BASED BASE MATERIAL - Google Patents

Abstract

The invention relates to a method for the continuous production of copper-clad base material for the printed circuit board industry. The features of the invention consist in that a condensation product of a phenol component, a formaldehyde component and an amine or a heterocyclic nitrogen compound is used as acceleration component for the resin-Haerter combination and that this component in one of the pressure-effective zone of the double belt press upstream activation zone so excited is that spontaneous pressure and temperature in the subsequent pressure-effective zone can take place until the curing of the laminate. {Base material; Printed circuit boards; Double belt press; continuous pressing; epoxy resin; Resin-hardener combination}

Description

Field of application of the invention

The invention relates to a method for the continuous production of copper-clad base materials for the circuit board industry.

Characteristic of the known state of the art

It is known, for the production of copper-clad base materials with thermosetting binders impregnated, pre-cured support materials (prepregs) one or more layers superimposed on top of each other to occupy with metal foil and discontinuously or continuously on double belt presses.

In DD-PS 235151, the continuous production of base material was published in a double belt press, which has been shown that process-related with the accelerated resin system impregnated and pre-cured laminates must be preheated before Einlaufet in the double belt press with viscosity reduction of the resin system.

The acceleration systems used are pyridine compounds, substituted imidazole compounds and imidazole itself in combination with dicyandiamide or benzyldimethylamine.

The same can be found in DD-PS 250090, in addition to a vacuum transfer operation is described.

It is also known that in DE-PS 3545159 is used with a Dopelbandpresse which has a defined temperature at the guide roller of 80-120 ° C, a pressure-free melting and evaporation zone of 1-2 m, with a gelling and Laminiorzone of 0.8-1.5 m is equipped, has a curing zone of preferably 2-4 m and completely waived a Kühlurig under pressure and operates in the pressure range of preferably 10bar.

When using the aforementioned binder systems, the relatively high solvent absorption of the laminates is disadvantageous because it leads to the deterioration of the mechanical and thermomechanical properties of the base material.

Object of the invention

The solution according to the invention should enable energy to be saved in the continuous production of copper-clad base material and a more uniform laminate quality to be ensured.

Explanation of the essence of the invention

The invention has for its object to provide a method for continuous production of copper-clad base material, which allows to achieve shorter curing times through the use of a matched epoxy resin hardener accelerator combination in order to positively influence the entire process flow.

The features of the invention are that the accelerator combination containing in the resin-hardener accelerator system used for the coating of the carrier webs in one of the pressure-effective zone of the double belt press upstream activation zone is excited so that a spontaneous pressure and temperature in the subsequent durkwirksamen Zone of the double belt press can be made to connect the coated carrier webs with the metal foil and to cure the laminate.

Preferably, a liquid condensation product of a phenol component, a formaldehyde component and an amine and / or a heterocyclic nitrogen compound is used as the accelerating component for the resin-hardener combination. It is important that for the preparation of the condensation product as the amine component preferably aliphatic and cycloaliphatic polyamines and as heterocyclic nitrogen compounds preferably imidazole or imidazole used werdon.

Further, it is important that, for the condensation product, the mole ratio of the phenol component to the formaldehyde component to amine and / or heterocyclic nitrogen compound 1 is from (0.6 to 1.2) to (0.5 to 6.0) and the molar ratio when used the combination of amine to heterocyclic nitrogen compound is 1 to 1 to 1 to 12. In addition, it is important that the accelerator is a condensation product of phenol, formaldehyde and a combination of dipropylene triamine and imidazole

 It is preferable that the accelerator used is a condensation product of phenol, formaldehyde and a combination and imidazole. It is further preferred that 0.05 to 1.5 parts by weight of the accelerator, calculated on anhydrous substance and based on the epoxy resin in the binder system are added.

It is also preferred that carrier material with a different degree of crosslinking is used.

It is important that outer materials coated carrier materials are used with respect to the inner layers increased degree of crosslinking.

Furthermore, it is important that the contacting of the outer layers of the coated carrier materials with the metal foil takes place already in the activation zone.

embodiment

The invention will be explained in more detail by exemplary embodiments. For the production process of copper-clad base material on double belt presses is used as an accelerator for the epoxy resin binder system, a liquid condensation product of a phenol component, a formaldehyde component and an amine and / or a heterocyclic nitrogen compound.

For the preparation of this condensation product, an aliphatic or cycloaliphatic amine is preferably used as the amine.

Examples of such an aliphatic olyamine are ethylenediamine, diethylenetriamine, propylenediamine, dipropylenetriamine-triethylenetetramine, tetraethylenepentamine, mixtures of polyethylenepolyamines, diethyleneaminopropylamine, N-hexylpropylenediamine, N-decylpropylenediamine, hexamethylenediamine and trimethylhexamethyldiamine.

As cycloaliphatic polyamines can be used diaminocyclohexane, Isophoiondiamin, Cyclohexylaminopropylamin, 4,4'-diaminodicyclohexylmethane, N-aminoethylpiperazine or N- (3-aminopropyl) piperazine.

The heterocyclic nitrogen compound of the condensate nsprodukte invention is preferably imidazole. However, it is also possible to use substituted imidazoles such as 2-methylimidazole, 4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 2-ethyl-4-methylimidazole, 2-ethylphenylimidazole and benzimidazole and derivatives thereof.

The phenol component of the condensation product used as accelerator is preferably phenol. However, it is also possible to use cresols, p-tertiary-butylphenol, resorcinol or dian.

The formaldehyde component used is a 35% to 40% strength aqueous formaldehyde solution or paraformaldehyde in solid form.

Condensation products of phenol, formaldehyde and amines are referred to as Mannich condensates. For the preparation of the Mannich condensate according to the invention, instead of the amino components, a combination of aliphatic *! or cycloaliphatic-amine with a heterocyclic nitrogen compound, preferably imidazole, or

Imidazole used alone. It is from a Einsatzmolverhältnis phenol to formaldehyde to amine and / or

heterocyclic nitrogen compound from 1 to (0.1 to 1.2) to (0.5 to 6.0).

If one uses a combination of amine and heterocyclic nitrogen compound, preferably imidazole, the Einsatzmolvehältnis of these compounds is 12 to 1 to 1 to 12.

The preparation of the Mannichbasenkondensates done in such a way that you first the phenol component, the

Formaldehyde component and the heterocyclic nitrogen compound, the mixture at 40 to 150 ° C over a

Reactive period of 30 minutes to 10 hours and adding the amine for further reaction in a period of 2 to 10 hours. The reaction temperature is 40 to 150 ° C, preferably 70 to 110 ⁰ C. It is advantageous to meter the amine so that the liberated heat of reaction is used to heat the reaction mixture and to control the temperature. The reaction water released in the condensation to the Mannich condensate and the water which is contained in the reaction mixture when working with aqueous formalin solution can, after the reaction by distillation in

Vacuum or normal pressure can be removed.

However, it is also possible to use a water-containing condensation product as accelerator, wherein the proportion of the accelerator to be added to the impregnating resin solution must be based on the proportion of the condensation product in the aqueous solution. The condensation products of phenol-formaldehyde, amine and / or imidazole are in any case clear, non-prone to crystallization liquids.

Epoxy resin hardener solutions, which are suitable as binders for the continuous compression of the resulting prepregs with copper foil to the desired base material for printed circuit boards, contain the accelerator according to the invention in a proportion of 0.05 to 1.0 wt .-%, based on the epoxy resin contained ,

As the epoxy resin for the binder system medium-molecular epoxy resins having an epoxide equivalent of 350 to 600, which may optionally be halogenated used. The hardener is dicyandiamide. The mass ratio of epoxy resin and dicyandiamide is 100 to 9 to 100 to 5. As solvents are known for the production of coating solutions

Used solvents such as xylene, toluene, methyl ethyl ketone, ethyl glycol, methyl glycol, acetone or Kombinat.onen their. example 1

In a reaction vessel with stirrer, thermometer and reflux condenser, 340 parts of phenol, 300 parts of paraformaldehyde and 340 parts of imidazole are added and heated to 50 ° C with stirring and introduction of argon as an inert gas. After a reaction time of 1 hour 685 parts of dipropylenetriamine are added over a period of 3 hours so that the

Reaction mixture is maintained at a temperature of 70 to 80 ° C without further heat supply. Subsequently, will

stirred again at 80 ° C for 3 hours.

There is obtained a clear yellow liquid having a viscosity, measured at 25 ⁰ C, of 497OmPa s and an amine value of 470mg KOhVg.

Example 2 In a reaction vessel with heater, stirrer, thermometer and reflux condenser are 800 TeMe phenol, 255 parts

Paraformaldehyde and 1156 parts of imidazole and heated to 9O ⁰ C under argon. The mixture is stirred for 6 hours at this temperature at reflux.

The product obtained is a light yellow liquid with a viscosity at 25 ^° C. of 74 mPas and an amine value of 404 mg KOH / g.

Example 3

The same molar ratio as in Example 2 is used, instead of paraformaldehyde, a 37% aqueous formalin solution is used. For this purpose, 658 parts of phenol, 567 parts of formalin solution and 952 parts of imidazole at 90 ° C over a period of 7 hours at reflux and under argon. A clear pale yellow liquid is obtained which has a viscosity of 13 mPa s at 25 ° C. and an amine value of 358 mg KOH / g.

The products of Examples 1 to 3 were stored at -15 ° C for a period of 30 days to determine crystallization tendency. All products are stable non-crystallizing liquids. Application examples of the accelerators according to the invention are given in Examples 4 and 5.

Example 4

From a commercially available epoxy resin, z. B. Araldit 8017 or DOW XZ 86792.02, dicyandiamide, 10% dissolved in methyl glycol, and the accelerator of Example 1, the following coating is prepared: 120 parts by weight DOW XZ 86792.02 30 parts by weight of dicyandiamide, 10% dissolved in methyl glycol 0.6 parts by weight accelerator according to Example 1

The B-time of this solution is 2.65 minutes after 2 hours of maturation. From this Lackierlösung and a glass fiber with a basis weight of 50-230g / m ² , a prepreg is produced with an outflow of 4.8%. The prepregs are pressed with 17,5, pm copper foil to 0.2 to 0.6 mm thick laminates in 190 seconds at 200 ° C. The measured properties of the laminate are summarized in Table 1.

Example 5

The preparation of the paint film and the processing over the stage of the prepregs were carried out analogously to Example 4, only 0.2 mass point of the condensation product prepared according to Example 2 were used as an accelerator.

B time after 2 hours Ripening time: 2.55 minutes Outflow of prepreg: 4.5%

The laminate characteristics are summarized in Table 1. '

Comparative Example 1

The preparation of the coating batch and the processing took place via the stage of the prepregs in analogy to Example 4, except that 0.2 part by mass of 2-methylimidazole was used as the accelerator.

B time after 2 hours Maturation time: 2.7 minutes. Outflow of the prepreg: 5.2% laminate properties, see Table 1.

Comparative Example 2

It is carried out according to Example 4, as an accelerator 0.3 parts by weight of benzimidazole are used.

B-time after 2 hours of ripening time: 2.75 minutes

Outflow of the prepreg: 5, C% s

Table 1: Characteristics measured from the laminate of Examples 4 and 5 and Comparative Examples 1 and

Laminate characteristics of the laminates

from example 3.5 5 3.3 Comparative example 6.0 2 8.0 4 3.0 3.5 1 8.0 10.0 Laminate thickness: 0.2 mm Thickness increase in 1.9 1.9 1.85 ¹ , 9 Methylene chloride (%) Water absorption (mg) VO VO VO VO Adhesion in the delivery condition (N / mm) Flammability according to UL94 0.9 0.8 2.0 2.4 (Step) 5.0 4.8 10.0 10.5 Laminate thickness: 0.6 mm Thickness increase in 2.0 1.95 1.9 1.8 Methylene chloride (%) Water absorption (mg) VO VO VO VO Adherence in the delivery condition (N / mm) Flammability according to UL94 0.9 0.7 3.2 4.0 (Step) 5.0 4.0 12.0 14.1 Characteristic values on the hardened 140 139 135 134.5 paint film Trichlorethylene uptake (%) Methyl ethyl ketone uptake (%) Glass transition temperature ( ⁰ C)

In order to achieve a high property constancy, it is advantageous to use those carrier webs which have a different degree of crosslinking in the processing of the solvent-free carrier webs. In order to improve the surface structure and the quality of the metal foil surface carrier webs are used for the outer layers, which have a higher degree of crosslinking than the inner layers.

As an important prerequisite for improved surface adhesion of the metal foil on the carrier webs, the contacting of the outer layers with the metal foil must already take place in the activation zone.

Claims (10)

1. A process for the continuous production of copper-clad base material for the printed circuit board industry, at the same time running from unwinding, coated with binders and pre-cured substrates, preferably glass fabric with one or both sides arranged metal foil, preferably electrolytic copper foil, divided into sections in variable heating and cooling zones Pressed double belt press with circulating steel strip, wherein as binder a resin-hardener-accelerator combination is used, characterized in that in the used for the coating of the carrier webs resin-hardener accelerator system containing accelerator combination in one of the pressure-effective zone of the double belt press upstream activation zone is so excited that a spontaneous pressure and temperature in the subsequent pressure-effective zone of the double belt press for connecting the coated carrier webs with the Metal foil and can be done to cure the laminate. 2. A method for the continuous production of copper-clad base material according to claim 1, characterized in that a! S acceleration component for the resin-hardener combination, a liquid condensation product of a phenol component, a formaldehyde component and an amine and / or a heterocyclic nitrogen compound is used. 3. A process for the continuous production of copper-clad base material according to claim 1 and 2, characterized in that are used for the preparation of the condensation product as the amine component aliphatic and cycloaliphatic polyamines and as heterocyclic nitrogen compounds imidazole or imidazole compounds. 4. A method for continuously producing copper-clad base material according to claim 1 and 2, characterized in that, for the condensation product, an insert molar ratio of the phenol component to the formaldehyde component to amine and / or heterocyclic nitrogen compound 1 is from (0.6-1.2) to (0.5-6.0) and the molar ratio at J - nwenciung the combination of amine to the heterocyclic nitrogen compound 1 to 1 to 1 to 12. 5. A method for continuously producing copper-clad base material according to claim 1 and 2, characterized in that the accelerator used is a condensation product of phenol, formaldehyde and a combination of dipropylenetriamine and imidazole. 6. A process for the continuous production of copper-clad base material according to claim 1 and 2, characterized in that a Kondencationsprodukt of phenol, formaldehyde and imidazole is used as an accelerator. 7. A method for continuously producing copper-clad base material according to claim 1 and 2, characterized in that 0.05 to 1.5 parts by mass of the accelerator, calculated on anhydrous substance and based on the epoxide in the binder system are added. 8. A process for the continuous production of copper-clad base material according to claim 1, characterized in that coated carrier materials are used with different degree of crosslinking. 9. A method for the continuous production of copper-clad base material according to claim 1 and 8, characterized in that coated as outer layers carrier materials are used with respect to the inner layers increased degree of crosslinking. 10. A process for the continuous production of copper-clad base material according to claim 1, characterized in that a contacting of the outer layers of the coated carrier materials with the metal foil takes place already in the activation zone.