UTC Agrees to Buy Kidde for \$2.8 Billion  LONDON/BOSTON (Reuters) - United Technologies Corp. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=UTX.N target=/stocks/quickinfo/fullquote"&gt;UTX.N&lt;/A&gt;  agreed on Thursday to acquire Britain's Kidde Plc &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=KID.L target=/stocks/quickinfo/fullquote"&gt;KID.L&lt;/A&gt; for  \$2.8 billion in cash in a deal aimed at expanding the U.S.  conglomerate's security system business.