custom post pagination

I have the following code when however the next posts and the previuos posts links doesn’t show on the page.

<?php
		$paged = ( get_query_var( 'paged' ) ) ? get_query_var( 'paged' ) : 1;
		$product_posts = new WP_Query(
			array (
				'post_status' => 'publish',
				'post_type' => 'product',
				'post_per_page' => 2,
				'paged' => $paged
			)
		);

		if( $product_posts->have_posts() ) : while( $product_posts->have_posts() ) : $product_posts->the_post(); ?>
			<div id="products">
				<div class="center">
					<div class="product-title">
						<?php the_title(); ?>
					</div> <!-- product-title -->
					<div class="product-image">
					<?php
						if( has_post_thumbnail() ) {
							set_post_thumbnail_size( 200 );
							the_post_thumbnail();
						}
					?>
					</div><!-- product-image -->
					<div class="price">
						<b>Price: </b><?php echo get_post_meta( get_the_ID(), 'price_text', true ); ?>
					</div><!-- price -->
					<div class="float-right">
						<?php
							$stock_meta = get_post_meta( get_the_ID(), 'stock_text', true );
							if( $stock_meta > 0 ) {
								echo '<span class="in-stock">In stock</span>';
							}
							if( $stock_meta <= 0 ) {
								echo '<span class="out-of-stock">Out of stock</span>';
							}
						?>
					</div><!-- float-right -->
				</div><!-- center -->
			</div> <!-- products -->
		<?php endwhile; endif; ?>
		<div class="clear-both"></div><!-- clear-both -->
  <div class="alignleft"><?php previous_posts_link('&laquo; Previous') ?></div>
  <div class="alignright"><?php next_posts_link('More &raquo;') ?></div>