woocommerce retriving category name as div class?

ok I am trying to retrive the category name of a woocommerce product displayed in a wordpress loop and use it as the class for a li also inside the loop i’ve tried this:

<div id="isocontent" class="products">

<ul><?php while (have_posts()) : the_post(); ?>

                            <li class="<?php echo $product->get_categories(); ?> box">
                                <a>"><?php echo the_post_thumbnail(); ?></a>
                                <p><a>"><?php the_title(); ?></a></p>
                                <a>"><span href="<?php the_permalink(); ?> " class="amount price" data-original="<?php echo get_woocommerce_currency(); ?><?php echo $product->get_price(); ?>" data-price="<?php echo $product->get_price(); ?>" title="Original price: <?php echo $product->get_price(); ?>"><?php echo get_woocommerce_currency(); ?><?php echo $product->get_price(); ?></span></a>
                                <a>?add-to-cart=<?php echo $post->ID ?>" class="pbutton">Add to Cart</a>

                        <?php endwhile; ?>
                    </ul>
                </div>

this being the part i’m trying to retrive the class with:

<li class="<?php echo $product->get_categories(); ?> box">

but it just outputs this:

<li class="<a href=" http:="" localhost.no="" fanny="" kategori="" interior-sv="" "="" rel="tag">

which does retrieve the category but also screws with the markup breaking the loop.
I’ve also tried this:

<li <?php post_class(‘box’); ?>

but because woocommerce uses taxonmys it retrives the tags but not the product category.
any help is much appriciated
Kind regards
Chris