How to set field permission with time limit
You can hide at all links to separately edit/delete field collections values, go to Structure » Content types » YOUR_CONTENT_TYPE » Manage display, click to field collection settings cogwheel and clear fields.


Also you have to forbid an access to edit/delete by direct link, place in your custom module:  

/**
 * Implements hook_menu_alter().
 */
function yourmodule_menu_alter(&amp;$items) {
  $path = 'field-collection/' . strtr('your_field_name', array('_' =&gt; '-'));
  $items[$path . '/%/edit']['access callback'] = FALSE;
  $items[$path . '/%/delete']['access callback'] = FALSE;
  $items[$path . '/add/*/*']['access callback'] = FALSE;
}


Don't forget to clear cache.