I am trying to insert loop data into database but it is giving an error

i am trying to insert loop data into database with laravel but it is giving the following error:

ErrorException in Grammar.php line 118: Argument 1 passed to Illuminate\Database\Grammar::parameterize() must be of the type array, string given, called in C:\xampp\htdocs\laravel\App\vendor\laravel\framework\src\Illuminate\Database\Query\Grammars\Grammar.php on line 678 and defined

View:

<input name="product_id[]" type="hidden" class="rid" value="13">
<input type="hidden" name="product_name[]" value="Popins"><input type="hidden" name="product_code[]" value="2323">
<input name="unit_price[]" type="hidden" value="170">
<input name="quantity[]" type="text" value="2" id="" >

Controller

for($i=0; $i<count($product_name);$i++){
$newSafety = new saleItems;
        $newSafety->product_id = $request->unit_price;
        $newSafety->sale_id   = $request->unit_price;
        $newSafety->product_code   = $request->product_code;
        $newSafety->product_name   = $request->product_name;
        $newSafety->quantity   = $request->quantity;
        $newSafety->unit_price   = $request->unit_price;
        $newSafety->gross_total= $request->unit_price;
        $newSafety->save();

        }

via Chebli Mohamed