18. Commitments and Contingencies

Pending Litigation

In connection with our May 1, 2012 acquisition of the Mead C&OP business, we assumed all of the tax liabilities for the acquired foreign operations including Tilibra Produtos de Papelaria Ltda. ("Tilibra"). For further information see "Note 11. Income Taxes - Income Tax Assessment" for details on tax assessments issued by the FRD against Tilibra, which challenged the tax deduction of goodwill from Tilibra's taxable income for the years 2007 through 2010.

We are party to various lawsuits and regulatory proceedings, primarily related to alleged patent infringement and employee terminations as well as other claims incidental to our business. In addition, we may be unaware of third party claims of intellectual property infringement relating to our technology, brands or products and we may face other claims related to business operations. Any litigation regarding patents or other intellectual property could be costly and time-consuming and might require us to pay monetary damages or enter into costly license agreements. We also may be subject to injunctions against development and sale of certain of our products.

It is the opinion of management that (other than the Brazilian Tax Assessment) the ultimate resolution of currently outstanding matters will not have a material adverse effect on our financial condition, results of operations or cash flow. However, there is no assurance that we will ultimately be successful in our defense of any of these matters or that an adverse outcome in any matter will not affect our results of operations, financial condition or cash flow. Further, future claims, lawsuits and legal proceedings could materially and adversely affect our business, reputation, results of operations and financial condition.

Lease Commitments

Future minimum rental payments for all non-cancelable operating leases (reduced by minor amounts from subleases) as of December 31, 2017 were as follows:



(in millions of dollars)
2018	$	28.1
2019	25.0
2020	21.6
2021	16.2
2022	12.2
Thereafter	17.6
Total minimum rental payments	120.7
Less minimum rentals to be received under non-cancelable subleases	2.0
Future minimum payments for operating leases, net of sublease rental income	$	118.7

Total rental expense reported in our Consolidated Statements of Income for all non-cancelable operating leases (reduced by minor amounts for subleases) amounted to $30.9 million, $24.2 million and $21.2 million for the years ended December 31, 2017, 2016 and 2015, respectively.

Unconditional Purchase Commitments

Future minimum payments under unconditional purchase commitments, primarily for inventory purchase commitments as of December 31, 2017 were as follows:



(in millions of dollars)
2018	$	96.8
2019	0.2
2020	0.1
2021	—
2022	—
Thereafter	—
Total unconditional purchase commitments	$	97.1

Environmental

We are subject to national, state, provincial and/or local environmental laws and regulations concerning the discharge of materials into the environment and the handling, disposal and clean-up of waste materials and otherwise relating to the protection of the environment. This includes environmental laws and regulations that affect the design and composition of certain of our products. It is not possible to quantify with certainty the potential impact of actions regarding environmental matters, particularly remediation and other compliance efforts that we may undertake in the future. In the opinion of management, compliance with the present environmental protection laws, before taking into account estimated recoveries from third parties, will not have a material adverse effect upon our capital expenditures, financial condition and results of operations or competitive position.