Process for formation of a hardened, insoluble or crosslinked stencil or resist image on a substrate, e.g., having a metal surface such as copper, and modifying the substrate or image surface comprising: A. forming an image on the substrate by applying a solvent-soluble thermoplastic copolymer of ethylene and .alpha.,.beta.-ethylenically unsaturated acid having an acid number of at least about 30, the copolymer reacting thermochemically with the substrate; B. fusing at a temperature and for a duration to induce the thermochemical reaction at a rate sufficient to partially insolubilize, harden or crosslink the polymeric image and adhere the polymeric image to the substrate surface to facilitate subsequent removal therefrom; C. modifying the uncovered substrate surface or the polymeric image surface, e.g., etching, plating, depositing, soldering; and D. removing the polymeric image. The image can be formed on the substrate by printing, electrostatic means, etc. The image may comprise particulate material having a plurality of fibers. The process is useful in making conductive printed circuits, chemical milling, etc.

A printed circuit board comprising an insulating board deposited with a catalyst having reactivity against electroless plating deposition, a resist for electroless plating provided on the insulating board excepting the part where a circuit is to be formed and a circuit formed by electroless plating, wherein the resist for electroless plating contains a coupling agent having a function of preventing the catalyst from ionizing. A process for producing the printed circuit board in which the insulating board surface excepting the part where a circuit is to be formed is covered with a resist for electroless plating containing a coupling agent having a function of preventing the catalyst from ionizing. Use of said resist for electroless plating can prevent drop of insulation resistance of the insulating board after moisture absorption.

Printed circuit boards containing thru-holes requiring metallization are manufactured by first applying to the board material an alkaline strippable resist in a predetermined desired pattern, thereafter applying material catalytic to subsequent metallization, thereafter treating the board with an aqueous alkaline solution to remove catalytic material from resist surfaces without adversely affecting the catalyst at non-resist areas, and then metallizing the non-resist areas. The ability to preliminarily apply the resist pattern before catalyst application, metallization, etc., yet prevent metallization of the resist, enables the manufacturing process to proceed straight through the activation, metallization, etc. steps without need for interruption for resist application.

An automobile grille which is selectively chromium plated so as to promote the flexural properties of the grille. By optimizing the flexural properties of the grille, the grille is more readily capable of withstanding a frontal impact without sustaining permanent damage. Preferably, the chromium plating is selectively deposited on exposed surfaces of the grille so as to minimize the detrimental effect which a hard and brittle chromium plating has on the flexural modulus of the grille. As a result, the grille is more readily able to flex under the load of an impact directed into the grille from the front of the automobile. In addition, chromium plating is deposited on surfaces of the grille which predominantly see compressive loading, so as to reduce the likelihood that the chromium plating will crack in tension. The grille is particularly suitable for mounting flush with an impact-absorbing bumper, such that the grille is capable of resiliently deflecting with the stroke of the bumper.

An automobile grille which is selectively chromium plated so as to promote the flexural properties of the grille. By optimizing the flexural properties of the grille, the grille is more readily capable of withstanding a frontal impact without sustaining permanent damage. Preferably, the chromium plating is selectively deposited on exposed surfaces of the grille so as to minimize the detrimental effect which a hard and brittle chromium plating has on the flexural modulus of the grille. As a result, the grille is more readily able to flex under the load of an impact directed into the grille from the front of the automobile. In addition, chromium plating is deposited on surfaces of the grille which predominantly see compressive loading, so as to reduce the likelihood that the chromium plating will crack in tension. The grille is particularly suitable for mounting flush with an impact-absorbing bumper, such that the grille is capable of resiliently deflecting with the stroke of the bumper.