Use either method (a) or (b) below:
$path = '\\apache\\htdocs\\prodacc\\downloads\\\\\\';
$a = $path . $name . '.zip';
$b = "$path{$name}.zip";
Regarding the \ at the end of $path, the first escapes the second so the second doesn't escape the last single quote. The use of {braces} is optional in $b.