How to insert two different values together into database whereas checkbox value and another input value such as quantity

I'm trying to insert two different value one is from a checkbox and one from different value such as quantity of the checkbox value beside it. I'm using foreach below as I am retrieving the books name saved into the database into the checkbox.

        @foreach($data as $data)
        <form action="" method="post">
        @csrf
        <div class="row col-12">
                      <div>
                        <p class='mybox text-dark'><input type="checkbox" name="prod_name[]" value=""/>
                    <input type="number" name="prod_qty[]" min="1" value="1"class="form-control">
                      </div>
          @endforeach
        </div>
</form>

When I use the code below it successfully inserts the data into my database, however it only saves the prod_name since that is the only thing I implode and inserted to my database.

public function bookreservation(Request $request)
{
            $data = new bookreservation;
            $data->name=$request->name;
            $data->email=$request->email;
            $data->phone=$request->phone;
            $data->address=$request->address;
            $data->date=$request->date;
            $data->time=$request->time;

            $prod_qty = $request->prod_qty;
            $selected_products = $request->prod_name;
            $products = implode(" ",$selected_products);
            $data->products=$products;

            $data->save();
            return  redirect()->back();

}

When I try to implode it together it gives me an error that "implode() expects at most 2 arguments, 3 given"

        $prod_qty = $request->prod_qty;
        $selected_products = $request->prod_name;
        $products = implode($prod_qty," ",$selected_products);
        $data->products=$products;

and if I remove " " inside the implode a different error is given "implode(): Argument #1 ($separator) must be of type string, array given" because I want to save both as one value and be inserted into the database as one as well and not separately.

What should I do to save two different values into one. Where prod_qty is beside or before the selected_products like 32 JasminBooks and if they insert/select another different value like 5 KnowHowBooks the result will be "32 JasminBooks, 5 KnowHowBooks," in the database and both are not separated.