Profile: Rainbow Bag Company UK Ltd. specializes in printing custom plastic bags, and custom paper bags. We use biodegradable materials in our plastic bags. We also offer a variety of other packaging products including bulk papers, and bubble wrap. Our plastic carriers fall into two main categories like high density polythene, and low density polythene. Our biodegradable bags break down into smaller fragments. These smaller pieces are then reduced to water, bio-mass and CO2.