HU192688B - Method for producing metal coated basic material of circuit plates - Google Patents

Abstract

A metal-laminated substrate material for printed circuit boards is manufactured in a double band press 1 in that laminate webs, which are impregnated with an accelerated resin system and pre-hardened, are preheated in a preheating zone 3 before entry into the pressure-active zone 2 of the double band press 1, and together with the metal foils are fed to the heating area 4 of the pressure- active zone 2, where the individual layers are compressed to form the substrate material. The substrate material is, in particular, cooled under pressure in the cooling area 5 of the pressure-active zone 2, following which it may be tempered, edge-trimmed and cut into lengths. Uniform substrate boards of totally satisfactory quality are obtained by means of the method and the apparatus.

Description

FIELD OF THE INVENTION The present invention relates to a method for producing a metal coated substrate for a circuit board by compressing laminated tapes and metal foil with a thermosetting resin in a press.

The metal-coated substrate of circuit boards is generally batchwise produced by pressing custom-sized thermosetting resin coated laminates and metal foils in an etch press. Such a process is expensive and results in varying quality of raw material within each circuit board. Therefore, there has long been a demand for continuous proceedings.

Progress towards continuity is the result of No. 2,108,427. GB patent application, which describes a process in which a press with two heating plates is intermittently pressed such that the web and copper foil introduced into the press are at rest during the pressing process and the pressed product is then released in stages. The end product of this process is thus sheets of individual sections, the size of which is limited by the size of the heating plate, and which are interconnected by uncompressed, thus unusable sections. Here, too, the quality changes within a single page, which, if the user wants homogeneous quality, leads to a large amount of scrap.

It is an object of the present invention to provide a continuous process for making a circuit board raw material.

In order to solve this problem, we have developed a process which involves pre-heating the accelerated resin impregnated and pre-hardened laminates prior to entering the double belt press printing zone by reducing the viscosity of the resin system and then pre-fabricating and crimping at an elevated temperature with metal foil.

Surprisingly, the non-pressurized preheating of the laminated tape with the thermosetting resin system allows for the use of a suitable double belt press and thus allows for the production of quality metal coated substrate strips, especially when considering the hardened, i. and that the hardening reaction of the accelerated pre-hardened resin system is further enhanced by preheating the laminates. The surprising effect of the invention on the professional world is particularly striking in light of the content of the English application cited above, which proposes that the resin should be cooled after application and prior to compression, i.e., the total reactivity of the resin to avoid unwanted prior reactions. during the pressing process, it is reserved for creating inter-layer joints.

Keeping in mind that this process relates to a resin which is normally hardening, that is to say, not accelerated and not pre-cured, the process of the present invention, i.e., preheating a resin that has already lost some of its reactivity during preheating and whose reaction capacity disappears quickly when warmed up - it seems just nonsense. Exactly the opposite of the state of the art, the pre-heating process step allows the continuous production of the metal-coated board material.

It is obvious that the pre-reaction induced by the preheating of the accelerated and pre-hardened resin activates the resin for the subsequent pressure reaction, thus undergoing a vigorous chemical process in the press itself.

The process of the present invention eliminates the discrepancies observed between the edges and center regions of the individual sheets in the batch or in the scheduled method described above, so that the resulting stock can be cut into sheets of uniform high quality and homogeneous quality.

The mode of operation of a double belt press, for example, in the production of laminated laminates is already known. In any case, the process according to the invention has created greater demands on the double belt press in terms of pressure and temperature. The same applies to the dimensional stability and surface finish of the products leaving the press.

Each of the laminates coated with the thermosetting resin system is bonded in front of the pre-heating zone of the double belt press. Here, the resin system is pre-hardened, usually to the B state. Here, we strive to achieve an advanced B-state, that is, a lower flow rate of resin than with the etch press. The multilayer laminate is uniformly heated in the preheating zone arranged in front of the pressure zone. Due to the decrease in viscosity, the resin will be soft and plastic, and even surface irregularities will be compensated. The preheating temperature depends on the resin system used, and is preferably from about 10 ° C to about 10 ° C. 80-100 ° C. From the preheating zone, the multilayer (layered) material is approx. It enters the pressure zone at 100 ° C. Preferably, the laminate is bonded with one or two separately preheated metal foils prior to entering the pressurized zone and, e.g. It is compressed at a temperature of from 150 ° C to 210 ° C under a pressure of 25 to 80 bar. The multi-layer feedstock is then cooled, preferably further pressurized, preferably maintained at the pressing pressure, preferably up to the glass transition point of the resin, optionally further tempered and cut to size. Cooling under pressure, i.e. in the press, is provided by the continuous process

-2192688

C is used to stabilize good quality, especially to prevent deformation of the material.

Examples of accelerated thermosetting resin systems include epoxy resin, polyester resin, phenolic resin, triacin, and the like. applicable.

An epoxy hardening catalyst is preferably used and the following pyridine bonds are used as accelerators, for example:

2-benzoylpyridine

3-benzoylpyridine

4-benzoylpyridine

2-benzylpyridine

3-benzylpyridine

4-benzylpyridine

2-benzylamino-pyridine

4-dimethylaminopyridine

2-methoxypyridine

4 tert.butilpiridin

3-cyanopyridine

4-hydroxypyridine

6-amino-2-pyridine

2-aminopyridine

3-ethylpyridine

3-ethyl-4-methylpyridine

2-phenylpyridine 6-diaminopyridine

3-methylpyridine

2- (aminomethyl) pyridine

2-amino-4-methylpyridine

2.4- dimethylpyridine

Another preferred class of accelerators is the following known imidazole linkages, including imidazole:

N-methylimidazole

2-methylimidazole

2-phenylimidazole

4-phenylimidazole

4 metiliraidazol

2 metilbenzilimidazol

5,6-dimethyl-benzimidazole

1-Rethyl-2-phenylbenzenedazole 1,2-dimethylimidazole

4.5- Diphenylimidazole

2-ethyl-4-methylimidazole carbonyldiimidazole imidazole

2 undocilimidazol

1-Cyanoethyl-2-phenylimidazole

2-phenylbenzimidazole

Particularly good results are obtained with the combination of dicyandiamide and benzyldimethylamine with the above-mentioned pyridines and imidazoles. In general, the present invention seeks to accelerate faster than known resin systems, in particular to achieve economical throughput in the press.

Further important advantages of the process according to the invention are:

- optimum material utilization in the manufacture of custom-made sheets since the continuous strip can be cut at any point,

- material savings, since only bilateral edging is required,

- energy savings, as there is no cooling process used in the etch press and hence energy loss,

- improvement of the quality of the laminate, in particular dimensional stability

- reduction of scrap due to cleaner copper foil surfaces.

The so-called. In contrast to the batch process of etching presses, there are significant savings in the number of work processes, which do not require prepreg cutting, metal foil cutting, prepreg bundling, laminate bundling, laminate bundling, expensive press plate and disposable pad paper.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in more detail with reference to the drawings, in which: FIG

Figure 1 shows a preferred embodiment of an apparatus for carrying out the process of the invention.

The apparatus for carrying out the process according to the invention (Fig. 1) is formed by a double belt press 1 having a pressure zone 2 and a pressure-free preheating zone 3 arranged in front of the pressure zone 2. The pressure zone 2 is divided into a longer heating zone 4 connected to the preheating zone 3 and a shorter cooling space 5 following the heating zone 4. The cooling space 4 is formed with three independently controllable temperature ranges 41, 42, 43. The double belt press 1 is provided with a pair of heated retractor baffles 6, 6 'arranged in pairs in front of the pressure zone 2 and a suitably shaped retractor baffle 7,7' arranged in pairs after pressure zone 2, wherein the retractor baffles 6,6 'are spaced apart like the 7.7 'pull-out deflectors. The retracting drums 11, 11 'of the retracting drum 6,6' are connected to the pressing belts 8,8 'of the double belt press 1. In order to maintain a constant temperature, the preheating zone 3 is bordered by a heat shield 9,9 'from the pressure roller 8 heated by the feed roller 6. The latter is a refrigerated plate. Cooling is provided by copper gaskets, and the flow rate of the coolant flowing through them is controlled, allowing precise temperature control. Forced cooling bags may be used instead of cooling snakes. The heat shields 9,9 'are movable horizontally so that the temperature-controlled preheating zone 3 can be approached or moved away from the pressure zone 2 and thus its spatial position can be controlled.

The principle of the double belt press according to the invention is based on the fact that the belt is continuously moved along the belt and continuously over the belt,

-3Ί constant pressure. This is done by transferring the pressure of the press pads (not shown) on the endless press belts 8 made of steel, which run synchronously with the press to be machined and serve as a finishing device. Preferred relatively large printing belts, approx. Use of 2 mm thick steel strips that provide good heat transfer.

For example, the length of the heating space 4 of the double belt press 1 may be 3 m, in which case the maximum construction length of the entire double belt press 1, i.e. the entire pressing zone 4 m. In this case, the length of the 3 preheating zones is 40-100 cm. In the preferred embodiment shown, the cooling space 5 is 1 m long.

In front of the double belt press 1, the spindle winder 12,13 is provided with two spindles 14,17 for the prepreg, i.e., a resin system coated fiberglass web, a glass wool or paper web, and an additional spindle winding 18 19, 21. with spool for metal foils. Between the spool winder 18 and the double belt press 1, guide rollers 22,22 'are arranged for the metal foils.

In the manufacturing process, after the double belt press 1, the edge cutter 23 and the cutting device 24 connected thereto are arranged.

During operation, four prepreg tapes, i.e., a resin-accelerated system and advanced B-stage laminated material are pulled from the spool winder 12.13 and are fed and fed into the preheating zone 3, wherein the four-layer material is ca. . Heat at 80-100 ° C without pressure. At the same time, metal foils are fed from the two spindles 19, 21 of the spool winder 18, which are separated from the prepreg between the respective heat shields 9 or 9 'and the press strips 8 and 8' and joined to the prepreg immediately before the press zone. While the temperature in the preheating zone 3 rises to 100 ° C, the temperature of the retracting drum 6,6 'is higher, so that the metal foil warms more intensively than the prepregs. In the three temperature ranges 41, 42, 43 of the heating zone 4 of the pressure zone 2, each of the bonded layers is pressed to its base material at a pressure above 25 bar and at a temperature of 150-190 ° C and bonded to the hardening of the still reactive resin. The temperature of the first temperature range 41 is lower than that of the second temperature range 42, which may be equal to the temperature of the third temperature range 43 and may be 190-200 ° C. In the next 5 chambers, the stock web is cooled under pressure.

At this delicate stage, applying pressure prevents quality loss, especially deformation of the product. The raw material tape is now approx. It cools to 100 ° C and leaves the 5 chillers. The subsequent edge cutter 23 removes the press edges from both sides of the web and the cutter 24 cuts it to the desired length.

A post-heating zone may be located between the cooling space 5 and the wind cutter 23 to provide for the initial stabilization of the feedstock.

Advantageous effect can be achieved by operating the furnace 4 in the depicted embodiment with a residence time which is approx. Corresponds to a feed rate of 3 m / min. The residence time and feed rate depend on the training temperature and reaction rate of the resin accelerator system used.

If only one-sided coated material is produced, a heat-resistant release foil may be wound into place of the metal foil and run into the double belt press 1. For example, the release liner is siliconized or polytetrafluoroethylene coated aluminum foil. Once the release liner has come out of the double belt press, it can be peeled off and reused from the finished web.

Although the process of the present invention is illustrated on a six-layer substrate, it is understood that other layers of material may be prepared.

The operating conditions described are primarily dependent on the resin system used and are suitably varied.

The process or apparatus of the invention may also be used for coating with copper or other metal foil. Particularly suitable for coating with composite foils, such as Cu / Al fine circuit boards (etchible / stripable boards).

The invention is further illustrated by the following examples:

EXAMPLE 1 A finished glass fabric weighing 200 g / m ² (practically used as a laminate of copper-coated fiberglass epoxy resin in circuit boards) was soaked in a resin solution containing 130 parts of polymeric partially brominated bisphenol A-glycidether. The latter consists of 1-15%, preferably 5-12% of epoxidized novolac, 3.2 parts of dicyandiamide, 028 parts of 3-methylpyridine and 80 parts of methyl glycol. The soaked impregnated prepreg had a resin content of 42% and a resin flow of 10%, dried at 165 ° C. Seven such prepregs, after preheating at 80 ° C, were pressed through a 35 mm thick copper foil to a 1.5 mm thick laminate on both sides with continuous flow at 150 ° C to 195 ° C and 45 bar pressure. Surprisingly, the dimensional stability results for the laminate test were above average and the other properties were equivalent to those of commercial laminates.

The resulting laminate has a thickness tolerance of ± 3/100 mm. for comparison, the tolerance of rigid laminates is ± 13/100, which is completely exhausted by the products obtained from the etch press.

Example 2

The glass tissue described in Example 1 was impregnated with a resin solution containing 100 parts of polymeric brominated bisphenol A-glycidether. Composition: 1-15%, preferably 5-12% novolak, 3.4 parts dicyandiamide, 0.33 parts 4-dimethylaminopyridine and 80 parts methyl glycol. The soaked impregnated prepreg had a resin content of 44% and a resin flow of 8%. After preheating at a temperature of 85 ° C, a plurality of such prepregs were continuously pressed into a laminate of 1.5 mm thickness with a 35 µm copper foil double-sided at a rising temperature of 155-200 ° C at a pressure of 50 bar. When testing the laminate, dimensional stability was found to be above the standard, the other properties being comparable to those of commercial laminates.

Example 3

A glass fabric weighing 100 g / m ² (for the application see example 1) was impregnated with a resin mixture containing 100 parts of polymeric partially brominated bisphenol A glycidyl ether. The latter consists of 1 to 15%, preferably 5 to 12%, of epoxidized novolac having a weight of 350 to 520 epoxy equivalents, 3.0 parts of dicyandiamide, 0.4 parts of 2-amino-4-methylpyridine and 80 parts of methyl glycol. The glass tissue was dried at 165 ° C. The resin content was 44% and the resin flow was 10%. After preheating two such prepregs at 80 ° C on one side, using a 35 µm thick copper foil, using a release film at a temperature of 150 ° C to 190 ° C, at a pressure of 50 bar, the apparatus of the present invention is We pressed it into laminate. The ₂ θ test showed the same good results as in Example 2.

Example 4-13> g Example 4-13. The formulas and operating conditions of Example 1 are summarized in the following table.

Example 4 δ 6 7 8 9 10 11 12 ' 13 resin ratio epoxy equivalents 100 100 100 100 100 100 100 100 100 100 lens weight 350/520 350/520 400/500 400/500 360/410 360/410 360/410 360/500 36C / 500 360/500 the proportion of epoxidized novolak in the base resin 5 5 5 5 10 10 10 5 10 15 dicyandiamide 3.3 3.3 3.3 3.0 3.0 3.4 3.1 3.2 3.2 3.0 methyl glycol benzildime- 80 80 80 80 80 80 80 80 80 80 tilamin 0:10 0:15 0:10 0:20 0:14 0:18 karbonildi- imidazole 4-methylimidazole 2-methylimidazole 2 metilbenz- 0:17 0:27 0:28 0:21 0:15 0:24 imidazole 0:22 / 0:18 2 feniliroidazol 2-ethyl-4-methyl- 0:30 0:21 imidazole 2-amino-4-methyl- pyridine 4-dimethylamino pyridine 4 tert.butil- 0.2 0:19 0:21 0:28 0:22 0:30 0:29 pyridine 3-benzylpyridine 0:16 0:25 0:17 0:15 glass fiber g / m ² lacquer thermometer 200 200 200 200 200 100 100 48 100 48 preparation of prepreg 160 160 170 165 165 170 160 165 165 160 resin content 43 43 44 44 43 49 48 50 50 60 resin flow pressing snow gauge 8 9 8 10 9 11 10 8 9 8 stool pressure (max.) 195 190 190 195 190 190 195 195 190 190 (bar) laminate iron 40 45 50 50 50 45 50 45 45 40 membership (mm) 1.6 1.5 1.6 1.2 1.0 0:17 0:54 0:05 0:25 0:15

pm copper plating

(E. = Sided k. = duplex) e k e k k k k k k k separating film X X - - - - - - -

-5il

Claims (18)

PATENT CLAIMS CLAIMS 1. A method of producing a metal coated substrate for a circuit board comprising compressing pressed laminated tapes with a thermosetting resin and a metal foil to be applied by pressurizing under pressure and heat, characterized in that the laminated strips impregnated and pre-pressed with accelerated resin system. Before entering the pressure zone of (1) (2), it is preheated to reduce the viscosity of the resin system, which is subsequently compressed with metal foil at elevated temperature, and then cut into the resulting web material 15. (Priority: April 10, 1984) 2. The method of claim 1, wherein said process comprises about 10 minutes. It is pressed at increasing temperatures from 180 to 210 ° C and pressures of 25 to 80 bar at 20. (Priority: 04.04.1984) 10.) Method according to claim 1 or 2, characterized in that the produced web material is cooled under pressure, preferably within the double ribbon press (1). (Priority: 1984. 4/10) 4. Process according to any one of claims 1 to 3, characterized in that the precursor material is post-tempered. (Priority: April 10, 1984) 5. A method according to any one of claims 1 to 4, characterized in that, in the manufacture of a material coated on one side of the metal, the film-free side 35 is guided together with the material and pressed together with a release film which is peeled off after the double belt press. (Priority: April 10, 1984) 40 6. A process according to any one of claims 1 to 3, characterized in that the laminated strips and the metal foil are preheated separately. (Priority: April 10, 1984) A process according to claim 6, characterized in that the metal film is preheated at a higher temperature than the laminated strips. (Priority: 04.04.1984) 10.) 8. A method according to any one of claims 1 to 5, characterized in that the laminated strips are joined to the metal foil immediately before the pressing zone (2) of the strip press (1). (Priority: 04/10/1984) 9. A process according to any one of claims 1 to 5, characterized in that fiberglass webs impregnated and pre-hardened with an accelerated epoxy catalyst system are used. (Priority: April 10, 1984) 10. A process according to any one of claims 1 to 6, characterized in that an accelerated epoxy resin hardening catalyst system comprising one or more bonds of the group consisting of 65 substituted pyridine bonds, imidazole, substituted imidazole, in particular in combination with dicyandiamide and benzyldimethylamine. (Priority: April 10, 1984) 11. The process of claim 10, wherein the accelerated epoxy resin hardening catalyst system comprises 0.2-0.8% by weight of the accelerator or accelerator mixture. (Priority: April 10, 1984) 12. Method according to any one of claims 1 to 3, characterized in that the laminated strips and the metal foil are compressed in a double belt press (1) provided with a pressurized heating space (4) and a pressure-free preheating zone (3) located in front of the heating space (4). (Priority: April 10, 1984) Method according to claim 12, characterized in that the laminated strips and the metal foil are preheated separately in a preheating zone (3) divided into different temperature ranges by means of a controllable cooled heat shield (9, 9 '). (Priority: April 10, 1984) Method according to claim 13, characterized in that the laminated strips and the metal film are passed through the preheating zone (3) and then through the pressure zone (2), wherein the preheating zone (3) and the pressure zone (2) distance is controlled by a heat shield (9, 9 ') movable in a horizontal direction. (Priority: February 2, 1985) 15. A 12-14. A method according to any one of claims 1 to 6, characterized in that the laminated webs and the metal foil are fed between a pair of retractable deflection drums (6, 6 ') in the pressure zone (2) of a double belt press (1) and after compression. ) from the double belt press (1), where the retracting baffles (6, 6 ') are spaced apart from the pulling baffles (7, 7'). (Priority: April 10, 1984) 16. Process according to any one of claims 1 to 3, characterized in that the raw material strips are cooled in a pressurized cooling space (5) connected to the heating space (4). (Priority: April 10, 1984) 17. A 12-16. Method according to any one of claims 1 to 3, characterized in that the laminated strips and the metal foil are pressed through three heating zones (4) having independently controlled temperature ranges (41, 42, 43). (Priority: February 2, 1985) 18. A 12-16. Method according to any one of claims 1 to 3, characterized in that the laminated strips and the metal foil are fed separately into the double strip press (1) by guiding devices arranged separately in the preheating zone (3). (Priority: April 10, 1984) 1 drawing The Director of Economic and Legal Publishing is responsible for the publication 88.557.66-4 Alföldi Nyomda Debrecen - Chief Executive Officer: István Benkő Chief Executive Officer 7