Laravel WhereIn method in Eloquent not working

I want to use the WhereIn method in Eloquent but it now works like the below function.

<?php 
  $product = DB::table('product')
                   ->join('supplier','supp_code','=','prod_supplier_code')
                   ->select('product.*','supplier.supp_margin')
                   ->where('prod_seo_title','=',$id)
                   ->first();

  $decArr = explode(',',$product->prod_decoration_type);

        for($i=0; $i<count($decArr); $i++)
        {
            if($i==0)
            $inString = "'".$decArr[$i]."','";
            elseif ($i<(count($decArr))-1)
            $inString .= $decArr[$i]."','";
            else
            $inString .= $decArr[$i]."'";
        }

        $proDeco = DB::table('decoration')->whereIn('deco_print_type', [$inString])->get();
?>

But In the query, it's displaying like this.

select * from `decoration` where `deco_print_type` in ('\'100109C9\',\'100110B9\',\'100144C9\',\'100186C9\'');

I can't understand why these slashes are coming. Please help me to fix this issue.

via Chebli Mohamed