SE413753B - PROCEDURE FOR MANUFACTURING A SUBSTRATE MATERIAL FOR PRINTED COUPLES - Google Patents

Description

É 7309928-s Å is 2 10 15 20 25 30 35 H0 when it comes to getting perfect. smooth and evenly thick surface layers, on which subsequent treatment steps can be performed with predictable results. Varnishing is also not suitable when you want to get resin-rich surface layers of the thickness required for the production of printed couplings.

It is also known to apply a resinous surface layer to paper or other materials by laminating or gluing a suitable plastic film to the surface of the material. A significant inconvenience with. this method is that the foil can be delaminated during use or under the influence of heat.

Additive processes for making printed couplings require a uniform resinous surface layer of at least 20 microns to provide strong and even adhesion of electrolessly formed metal coatings and to provide smooth surfaces for copying. To date, sheet size laminates, which have been cut into slabs (eg 100 X 200 mm), have been coated separately by several methods, including rolling, dipping and spraying. These methods give poor regulation of the thickness and cause production technical difficulties, since you have to handle a large number of plates.

These and other disadvantages of known methods are overcome by the present invention.

Fig. 1 shows an apparatus for coating a transfer material with a layer of curable resin. 7 Pig. 2, 3 and H show transversely of a resin substrate coated with a cured resin layer and a transfer material, of the substrate with the transfer material removed and of the substrate with the exposed cured resin-rich surface activated for receiving metal.

The invention relates to a process for producing a substrate material for printed couplings, which has a resin-rich surface layer of controlled thickness and predetermined mechanical, chemical, electrical and optical properties. The process consists in coating a film of a transfer material with a layer of a viscous liquid polymeric composition which is cured by polymerization or crosslinking, the overcoat material not adhering to the coating layer in the cured state, or partially curing the composition to such an extent that do not adhere to each other, to subsequently bring the partially cured coated surface of the film into intimate contact with a permanent substrate, which adheres to the coating layer in its cured state, to complete the curing of the coating layer by polymerization or crosslinking and then peeling off the film, as further specified in claim 1.

The coating composition is preferably applied without or substantially without solvent and is unpolymerized. It is important to then partially cure it, i.e. to the "B-stage", to get a non-sticky and not completely hardened surface. This makes it possible to wrap the coated transfer mineral foil into a roll without the risk of it forming a rigid block which cannot be rolled up. In addition, the risk of the resin penetrating the surface layer is avoided, and the production of permanent substrates having different surface layers of resin compositions, such as epoxy resins, binders, etc., is simplified by pre-mixing. The transfer film may be, for example, plastic or metal-coated paper, such as silicone-coated paper, polyethylene-coated paper or aluminized paper, plastic films, such as polyethylene, polyvinyl chloride, polyvinyl fluoride and polyesters, e.g. polyalkylene terephthalate, and metal foil, such as aluminum, tin or copper.

In some cases it may be advisable to use a release agent, e.g. a wax or a silicone, to facilitate the peeling off of the transfer foil after the coating has hardened. In preferred embodiments, the surface of the permanent substrate (after peeling off the transfer foil) is suitable for receiving adhesive metal deposits. It is a binder.

In other embodiments, the resin-rich surface layer, which may be an adhesive layer, can be post-treated in a known manner to make it permanently polarized and microporous.

This provides an activated substrate for metallization with_improved joint strength. Polarization and wettability are induced, for example, by treating the cured resin surface first with a pre-activating agent, e.g. dimethylformamide, dimethylsulfoxide or a mixture of toluene and water, depending on the nature of the cured resin, then with an activator such as a mixture of chromic acid and sulfuric acid, and then with a reducing agent such as sodium sulfite. The result of this treatment is a permanently polarized wettable surface. Such methods, including methods for electroless metallization, are described in more detail in Swedish patent application 7302091 ~ 9.

The curable composition may also be partially degradable or contain degradable particles, such as resin particles with reactive sites, and be rendered microporous and thus activated to receive adhesive metal coatings by treatment with suitable means. such as chromic acid or permanganate. Such compositions and methods, including electroless metallization, are further described in U.S. Pat. No. 3,625,758. The group of suitable coating materials is not limited to the foregoing. The material may be a monomer combination, a catalyzed monomer, a catalyzed mixture of monomer and polymer or a two component material. Preferred resins are phenolic resins, polyepoxides, melamine resins, polyacrylates, polyesters, nitrile rubbers, curable styrene resins and mixtures thereof.

In a preferred embodiment of the invention, the permanent substrate material itself is curable by polymerization or crosslinking and the coating layer and the substrate material are cured simultaneously before peeling off the transfer foil.

In other preferred embodiments, the coating or resin-rich surface, which has been cured simultaneously with the substrate, is consistently catalytic for deposition of metal from electroless metal deposition solutions. Such surfaces do not need to be treated with sensitization baths to become catalytic, which simplifies the manufacture and facilitates the production of printed couplings, since boreholes in such materials have catalytic walls, whereupon conductive metal layers can be deposited by immersion in electroless baths.

It is also conceivable to use materials which are consistently catalytic for electroless deposition of metal, as permanent substrates. For example, a curable catalytic pulp of the type disclosed in U.S. Pat. No. 3,226,256 and Canadian Pat. No. 895,590 may be used. Essentially, the pulp contains a dispersion in a resin binder of fine particles of an agent; which is susceptible to electroless metal deposition, e.g. a metal, 1, such as titanium, aluminum, copper, iron, cobalt, zinc or mixtures, of these or any other metal in group IB, IV or VIII, or a salt, a complex or an oxide thereof, such as a chloride, a bromide, a fluoride, an ethyl acetoacetate, a fluoroborate, an iodide, a nitrate, a sulphate, an acetate or an oxide of such a metal.

Particularly useful are palladium, gold, platinum, copper, palladium chloride, gold chloride, platinum chloride, copper oxide and stannous chloride. The content of catalytic compound in the cured coating or the resin-rich layer is usually between 0.001 and 25% by weight. Preferably, the content of catalytic compound is below 10% by weight. According to Figure 1, the process is carried out on a large scale by coating the transfer foil 2 with the resin-rich layer U between rollers 6 and 8 and wrapping the coated foil. to a roll 10 after the resin layer has been partially cured to the B stage by heating with lamps 16. Then pieces of the required size (eg 900 x 1200 mm) are cut off, which are combined with blanks of substrate material and joined to them by heat and pressure in a lamination press.

The article removed from the press looks as shown in cross section in Figure 2 and comprises the transfer foil 2, the permanent substrate 12 and the cured coating layer H. Figure 3 shows the coated substrate after the transfer foil has been peeled off.

Figure U shows a preferred embodiment where micropores 1H are accommodated in the surface layer. These are filled with metal during the later possible metallization and facilitate the adhesion of the metal to the resin-rich surface. The transfer foil can be used both as a means for applying the curable resin to the blank and as a release agent in the press.

In laminate manufacturing, the process offers the following advantages. The small thickness requirement of the resinous layer can be easily met by slight overdose of the wet film thickness, which avoids the problem of solution coating of individual plates.

Large-scale paving on a running track is much faster and is more economical than paving individual small pieces. The processing can easily be integrated into existing processes and devices for laminate production. You get a denser and smoother surface layer, which is more free of fine holes, withstands handling better, has better resolution in copying processes and gives higher peel strength of later applied metal layers than coatings obtained from solution. The transfer process enables the use of a different resin in the surface layer than within the laminate. Previous attempts to coat phenolic resin blanks with resin surface layers have resulted in penetration and mixing of the resin in the substance with the surface layer resin. Since the resin in the blank is not activated for adhesion in the manner prescribed for the applied surface layer, unpredictable and low values of the peel strength have often been obtained after metallization. Manufacturers of refractory laminates with resin-rich surfaces can advantageously apply the present method. The measures currently applied involve double or triple dipping of the glass fabric, which has poor uptake, use of fine mesh fabric, which has better uptake, addition of expanded silica to increase the resin uptake and 10 15 20 25 30 ace H0 'silica and sufficient with methyl ethyl ketone, cellosol acetate and precise control of the flow by difficult and expensive settings K = of drying conditions and catalysts. The transfer foil material can be intentionally selected so that it adheres to the applied resin surface layer to form spacers during stacking as well as provide protection during punching of plates, perforation and drilling. If it is not removable by hand, the transfer pad may be chemically removable, as is the case with aluminum foil. The following examples illustrate the invention.

Example 1 A transfer film in the form of polyethylene coated paper is coated with a layer of a curable rubber mass and dried. The treatment and drying takes place while peeling the paper from one roll and winding the dried paper on another roll.

The rubber mass is made from 350 g of liquid nitrile rubber, 590 g of lump nitrile rubber, 350 g of curable oil-soluble phenolic resin, 100 g of epoxy resin (epichlorohydrin derivative), 300 g of fumed colloidal butyl carbitol in a weight ratio of 1: 5.7: H, H to give of about 12,000fcP. 900 X 1200 mm sheets are cut from the paper web and arranged in a stack down several blanks of phenolic resin impregnated paper or glass fiber reinforced epoxy resin, so that the resin layer abuts the blank. The stack is laminated under normal conditions (phenolic resin ~ 70 - 105 kp / cm 2 at 17,000 for 45 minutes, epoxy resin 1H - 19 kp / cm 2 at 170 ° C for 15-30 minutes). Plates cut out of the laminates with a resin-rich surface layer are processed into printed coupling plates in the following way. First, the required holes are taken up, after which the transfer foil is removed, e.g. peeled off. The surface is activated for 30 minutes at 23-27 ° C in a mixture of 37 g of potassium bichromate, 500 ml of sulfuric acid and 500 ml of water. The surface is sensitized by treatment with a solution of 100 g of tin chloride, 55 ml of concentrated hydrochloric acid and 1000 ml of water. and treated in a bath of 1 g of palladium dichloride, H0 ml of concentrated hydrochloric acid and 1000 ml of water.The plate is dried, and a conventional mask is applied.Copper is deposited from a conventional electroless working bath (e.g. according to U.S. Pat. No. 3,625). 758, Example 5) to the desired thickness, so that the desired line pattern is obtained.The mask is peeled off, and the finished coupling plate is post-cured for 30 minutes at 1BOOC.

Example 2 Instead of the rubber coating used in Example 1, a coating of epoxy resin (eg resin of epichlorohydrin and bisphenol A, catalyzed with diethylcrylamine) is applied by the transfer process. After curing, punching and stripping the transfer foil, the surface layer is made permanently polarized and wettable by dipping in dimethylformamide at 27 DEG C. for 2 to 5 minutes, rinsing with water, dipping in an aqueous solution of 100 g / l chromium trioxide and 250 ml / l concentrated sulfuric acid for about 1 minute, dipping in a 5% solution of sodium hydrogen sulphite for 2 minutes, rinsing in cold water and in warm (70 ° C) water and drying in air or drying cabinets. Then the activated substrate is sensitized, e.g. with a loose ice Peakf io fl spfodukf of palla: iumaiklør ia and theme in chloride (see Swedish patent application 1193/71) and masked. An electrolessly deposited copper conductor pattern is built up to the desired thickness, the mask is peeled off, and the printed coupling plate is post-cured in the manner indicated above. In Example 3 epoxy resin, 15 g butadiene-acrylonitrile rubber, 50 g diacetone alcohol, 50 g toluene, 11 g oil-soluble phenol formaldehyde resin and 60 g cuprous oxide (catalyst). The epoxy resin used is a reaction product of epichlorohydrin and bisphenol A with epoxy equivalents 173 - 179, average molecular weight 300 - 350 and viscosity 3600 - euoo CP at 2 ° C.

Instead of copper baths, you can use other electrolessly operating baths of metals in groups IB and VIII, tlex. the nickel baths, described in Brenner, Metal Finishing, nov. 1960, p. 68-76, or the gold baths described in U.S. Pat. No. 2,970,181. Similarly, baths of cobalt, silver or other metal numbers well known to those skilled in the art may be used.

Poon QuAuTv

Claims (4)

7309928-5 'The foil (2, H) is peeled off from the supply roll (10) and laid with a surface. 9. A process for producing a substrate material for printed couplings, which on a support layer has a surface layer of resin, plastic or a mixture n suitable therefor, of which with or without filler, characterized in that a foil (2) of transfer material is peeled off from a supply roll and coated on one side with a layer (4) of an unpolymerized material intended for the formation of the surface layer, the viscosity of which is set to a value suitable for coating, that the foil (2, H) thus coated is subjected to curing to the extent that the coated foil can be wound on another supply roll (10) and stored until further processing and that upon subsequent compression of the surface layer (4) with a carrier layer or a plastic or resin impregnated blank serving for its production, plastic or the resin impregnation through the surface layer is excluded, that in a later step the coated layer (H) against the carrier layer (12) or the plastic used for its production the resin-impregnated substance and is thus connected during curing, suitably by means of heat and pressure, and that the foil (2) is removed at a suitable time before or during the production of a printed coupling plate. A layer of transfer material is laid with the coated side inwards on a method according to claim 1, characterized in that the coated foil removed from the supply roll (10) is a stack of impregnated carrier layer blanks and is thus bonded while pressing the stack into laminate and simultaneous curing. 3. k e n n e - A method according to claim 1 or 2, the surface of the foil (2) to be coated is coated with a release medium before the surface layer (4) is applied. Method according to one of Claims 1 to 3, characterized in that the surface layer (H) is partially cured on the foil (2) by means of heat radiation or ultraviolet radiation. PROMISED PUBLICATIONS: Germany 1 779 691 (6290 9/09) _ u-s rs 539 424 (156-238), s aso sso (161-89)