EXHIBIT 21

SUBSIDIARIES OF WESTLAKE CORPORATION *

Name of Subsidiary	State or Other Jurisdiction of Incorporation or Organization	Names Doing Business
Axiall Canada, Inc.	Canada	Axiall Canada, Inc.
Axiall, LLC	Delaware	Axiall, LLC
DaVinci Roofscapes, L.L.C.	Kansas	DaVinci Roofscapes, L.L.C.
Westlake Dimex LLC	Delaware	Dimex LLC
Eagle Natrium LLC	Delaware	Eagle Natrium LLC
Eagle Spinco Inc.	Delaware	Eagle Spinco Inc.
Eagle US 2 LLC	Delaware	Eagle US 2 LLC
LASCO Fittings, LLC	Delaware	LASCO Fittings, LLC
North American Pipe Corporation	Delaware	North American Pipe Corporation    and NAPCO
North American Specialty Products LLC	Delaware	North American Specialty Products LLC
Plastic Trends, Inc.	Michigan	Plastic Trends, Inc.
Rome Delaware Corp.	Delaware	Rome Delaware Corp.
Royal Building Products (USA) Inc.	Delaware	Royal Building Products (USA) Inc.
Royal Group, Inc./Groupe Royal, Inc.	Canada	Royal Group, Inc., Groupe Royal, Inc.    Produits de Bâtiment Royal, Royal    Building Products, Royal Building    Solutions, Roytec Vinyl and NAPCO    Royal Pipe & Fittings
Taiwan Chlorine Industries Ltd.	Taiwan	Taiwan Chlorine Industries Ltd.
Vinnolit Benelux-France B.V.B.A.	Dendermonde, Belgium	Vinnolit Benelux-France B.V.B.A.
Vinnolit GmbH & Co. KG	Ismaning, Germany	Vinnolit GmbH & Co. KG
Vinnolit Holdings GmbH	Ismaning, Germany	Vinnolit Holdings GmbH
Vinnolit Italia S.r.L.	Milan, Italy	Vinnolit Italia S.r.L.
Vinnolit Limited	United Kingdom	Vinnolit Limited
Vinnolit Monomer Geschäftsführungs GmbH	Ismaning, Germany	Vinnolit Monomer Geschäftsführungs GmbH
Vinnolit Treuhand GmbH	Ismaning, Germany	Vinnolit Treuhand GmbH
Westlake Chemical OpCo LP	Delaware	Westlake Chemical OpCo LP
Westlake Chemical Partners GP LLC	Delaware	Westlake Chemical Partners GP LLC
Westlake Chemical Partners LP	Delaware	Westlake Chemical Partners LP
Westlake Compounds LLC	Delaware	Westlake Compounds LLC
Westlake Germany GmbH & Co. KG	Germany	Westlake Germany GmbH & Co. KG
Westlake International I B.V.	The Netherlands	Westlake International I B.V.
Westlake Longview Corporation	Delaware	Westlake Longview Corporation
Westlake Management Services, Inc.	Delaware	Westlake Management Services, Inc.
Westlake Petrochemicals LLC	Delaware	Westlake Petrochemicals LLC

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Westlake Polymers LLC	Delaware	Westlake Polymers LLC
Westlake Royal Building Products Inc.	Delaware	Westlake Royal Building Products Inc. and Boral Building Products Inc
Westlake Royal Roofing LLC	Delaware	Westlake Royal Roofing LLC and Boral Roofing LLC
Westlake Royal Stone LLC	Delaware	Westlake Royal Stone LLC and Boral Stone Products LLC
Westlake Royal Windows LLC	Delaware	Westlake Royal Windows LLC and Boral Windows LLC
Westlake Styrene LLC	Delaware	Westlake Styrene LLC
Westlake Switzerland GmbH	Switzerland	Westlake Switzerland GmbH
Westlake Vinyls Company LP	Delaware	Westlake Vinyls Company LP
WPT LLC	Delaware	WPT LLC

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*    Westlake has elected to omit the names of certain subsidiaries. None of the omitted subsidiaries, considered either alone or together with the other omitted subsidiaries of its immediate parent, constitutes a “Significant Subsidiary” as set forth in Section 601(b)(21) of Regulation S-K.

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