laravel jsValidation error while using unique rule

I am having issue while using laravel unique rule in CreateRequest with JsValidation. Here is the Request code.

class CreateProductRequest extends Request
{

    public function rules()
    {
        return [

            'factory_id' => 'required',
            'category' => 'required',
            'product_code' => 'required|unique:product',
            'un_code' => 'required|unique:product',
            'hs_code' => 'required|unique:product',
            'section' => 'required',
            'status' => 'required',
            'product_type' => 'required',
            'classification' => 'required',
            'main_product_market' => 'required',
            'custodian_user_id' => 'required'

        ];
    }
}

When I remove the unique field its fine. But with unique rules I would get 500 server error as follows

In console it reports

It worth noting that if I don't use the JSValidation Laravel will produce no errors

Update :

In the Debug Bar I am getting this error

'PDOException' with message 'SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '' for key 'name'' in /.../demo/vendor/laravel/framework/src/Illuminate/Database/Connection.php:408:

The issue was later solved. My issue was that I was not typeHinting the CreateProductRequest and was instead using Request.

I should have been typeHinted the extended Request class that declares the rules.