Try using a property group class where you can store all your properties.
import bpy
class MaterialSettings(bpy.types.PropertyGroup):
my_int = bpy.props.IntProperty()
my_float = bpy.props.FloatProperty()
my_string = bpy.props.StringProperty()
bpy.utils.register_class(MaterialSettings)'
Assigning these values to the Object like this:
bpy.types.Object.my_settings = bpy.props.PointerProperty(type=MaterialSettings)
Note: you can choose a custom name instead of 'my_settings'
And the name after the 'type=' is the classname of your property group .
You can access these properties like this: object.my_settings.my_float = 3.0 object.my_settings.my_string = "Foo"
This way, only the propertyclass will be visible in the properties tab and is only editable via script!