Intangible Assets

12 Months Ended

Sep. 30, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible Assets

10.INTANGIBLE ASSETS

The table below provides details of acquired intangible assets:

	September 30, 2017							September 30, 2016
	Gross		Accumulated Amortization			Net		Gross		Accumulated Amortization			Net
(In millions)
Customer relationships	$	79.5	$	(22.7	)	$	56.8	$	80.4	$	(19.5	)	$	60.9
Patents and technology	50.3		(37.9		)	12.4		46.4		(34.2		)	12.2
Other	3.2		(1.6		)	1.6		3.2		(1.5		)	1.7
Total Intangible Assets	$	133.0	$	(62.2	)	$	70.8	$	130.0	$	(55.2	)	$	74.8

The intangible assets primarily pertain to the Materials segment and have a remaining useful life of approximately 17 years for customer relationships and 5 years for patents and technology.

Amortization expense for intangible assets was $7.6 million, $7.5 million, and $8.8 million in 2017, 2016, and 2015, respectively.

Projected annual amortization expense for intangible assets as of September 30, 2017 is as follows:

2018	$	7.2
2019	5.9
2020	5.8
2021	5.8
2022	4.9
Thereafter	41.2
Total	$	70.8

In 2017, Versum acquired the intellectual property and related assets of Dynaloy through a business combination. Refer to Note 23, "Acquisition," for further discussion of the related intangible assets and goodwill.