In the shopping malls, supermarkets, at home, in restaurants and on all kinds of occasions, you can see paper bag everywhere. A paper bag, one of the daily necessities, it is a container for objects. It is a kind of environmental protection product made of paper. Common material of paper include: cardboard paper, white cardboard paper,coated paper, craft paper, and a small amount of specialty paper. The most common paper is white cardboard, because of its strong texture, generally 210 g/m2 cardboard bags which can bear 3~5 kg , if more heavy leather or other items, with 250 grams of white card bearing effect will be better, while printing effect is good, the price is moderate, a choice for high-end products. Coated paper is a kind of material which is not commonly used. Its quality is softer than that of white cardboard paper. The conventional thickness is 175 grams. The printing effect is the same as that of white cardboard paper. It also needs laminating. The price is almost the same as white cardboard. Cardboard and double white material price is more cost-effective, can be said to be a kind of material in the paper the cheapest. Cardboard paper, as the name suggests, refers to one side is white, one side is gray paper, the minimum thickness of cardboard is 250 g/m2, the hardness to be more soft, the effect of printing is almost the same as white cardboard paper.Because it also needs laminating. Double white as same as cardboard , only two side are white, the middle material is gray, and the price is a bit higher than some cardboard.