The company continued to benefit from higher net sales in both the Performance Materials and Thermal/Acoustical segments. Operating income for the second quarter of 2011 was $5.0 million, or 5% of net sales, compared to operating income of $2.6 million, or 3.4% in the second quarter of 2010. This improved performance was primarily driven by the operating results of the Thermal/Acoustical segment, which reported operating income of $2.6 million compared to breakeven operating results in the second quarter of 2010.
Excluding the impact of foreign currency translation, net sales for the current quarter increased by $17.4 million, or 22.6%, compared to the second quarter of 2010. The increase was primarily attributable to higher sales volumes in the second quarter of 2011 from the Thermal/Acoustical segment of $14.6 million, or 34.7%, compared to the same quarter a year ago. In addition, the Performance Materials segment net sales increased in the second quarter of 2011 by $3.2 million, or 10.2%, compared to the same quarter a year ago. Net sales of OPS in the second quarter of 2011 decreased by $0.4 million, or 11.1%, compared to the same quarter a year ago.
During the second quarter of 2010, the company recorded a gross gain on sales of $2.6 million, or a net gain on sales of $1.7 million, after a write-off of $0.9 million of goodwill that was allocated to the electrical papers product line, related to the delivered elements during the quarter ended June 30, 2010, and deferred $3.2 million. The deferred amount is being recognized as income as services under the license agreement are delivered in periods subsequent to the sale, including $0.4 million and $0.8 million recognized during the quarter and six months ended June 30, 2011, respectively.