diff --git a/src/ifcopenshell-python/ifcopenshell/api/pset/add_pset.py b/src/ifcopenshell-python/ifcopenshell/api/pset/add_pset.py
index 0a032b2a4e..e9cd52ddf6 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/pset/add_pset.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/pset/add_pset.py
@@ -43,8 +43,8 @@ class Usecase:
             self.settings["product"].HasPropertySets = has_property_sets
             return pset
         elif self.settings["product"].is_a("IfcMaterialDefinition"):
-            for definition in self.settings["product"].HasPropertySets or []:
-                if definition.Name == self.settings["name"]:
+            for definition in self.settings["product"].HasProperties or []:
+                if definition.Name == self.settings["Name"]:
                     return definition
 
             return self.file.create_entity(
diff --git a/src/ifcopenshell-python/ifcopenshell/api/pset/data.py b/src/ifcopenshell-python/ifcopenshell/api/pset/data.py
index e68f9394ef..0ea2bc6f21 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/pset/data.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/pset/data.py
@@ -59,8 +59,9 @@ class Data:
     @classmethod
     def add_pset(cls, pset, product_id):
         data = pset.get_info()
-        del data["OwnerHistory"]
-        del data["HasProperties"]
+        if not pset.is_a("IfcMaterialProperties"):
+            del data["OwnerHistory"]
+            del data["HasProperties"]
         if hasattr(pset, "HasProperties"):
             props = pset.HasProperties or []
         elif hasattr(pset, "Properties"):