<?php
/**
 * Prevent products being purchased from archive
 * @return Boolean
 */
function pewc_filter_is_purchasable( $is_purchasable, $product ) {
	if( is_archive() ) {
		return false;
	}
	return $is_purchasable;
}
add_filter( 'woocommerce_is_purchasable', 'pewc_filter_is_purchasable', 10, 2 );