<?php
 
$texto = "Nome do produto teste cadastrado no banco";
 
function divStr($string){
   $texto1 = $texto2 = "";
   $array = explode(" ", trim($string));
   $array_len = sizeof($array);
   $limite = $array_len%2 == 0 ? $array_len/2 : floor($array_len/2);
 
   $texto1 = implode(" ", array_slice($array, 0, $limite+1));
   $texto2 = implode(" ", array_slice($array, $limite+1));
 
   return [$texto1, $texto2];
}
 
var_dump(divStr($texto));

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