Familiar may pulp sound, two terms softwood pulp and hardwood pulp are of ambiguity to a large number of people. Actually, they are two main types of pulp, each of which possesses typical characteristics needing to take into consideration. Hence, let’s figure out these interesting features in this article!
Facts about softwood and hardwood:
In general, wood plays a crucial role in pulp making, accounting for up to about 90%. However, there arises a question that how can we differentiate two types of pulp? In fact, they are distinguished by their reproduction and components rather than their appearance. Detailedly, hardwood ( scientifically called as gymnospermae ) comes from deciduous trees – ones that shed their leaves annually. This explains why hardwood pulp are commonly made of Oak, Poplar and Basswood as well.
Conversely, softwood generally comes from conifer and; therefore; includes Red pine, Inus massoniana or Larch. Undoubtedly, hardwood is found much harder than softwood and its proportion in wood fibers is estimated twice as much as softwood’s.
Accordingly, pulp is divided into softwood pulp and hardwood pulp. They are both indispensable in paper industry, but have typically different features. Okay let’s explore!
Typical features of hardwood and hardwood pulp:
It is versatile that people have to think of first when mentioning hardwood. The wonderfully condensed and complex feature gives this material not only prominent strength but also amazing toughness. In actual fact, the percentage of wood cellulose in hardwood pulp is surprisingly 40-70%, the rest sees duct with 20-40%, wood ray 10-20% and parenchymal cell at 2-13%. Due to the high ratio parenchymal cell, hardwood has low strength but strong absorptivity and high opaqueness. That is the reason why hardwood pulp is mainly used in printed paper manufacture.
On a detailed basis, it is necessary to discuss hardwood pulp in terms of fiber, paper character, application and price. Regarding fiber, hardwood pulp fiber is rather short and thick as they come from hardwood with large size and weight as well as hard characteristic. Also, the level of purity is not as high as that of softwood pulp. Relating to paper character, hardwood pulp gives paper high thickness and strong absorptivity.
Even though hardwood pulp is not perfectly flexible and ; therefore; not really perform well in paper making, hardwood pulp is usually mixed with softwood one in coated paper or offset paper making. Nevertheless, it solely apply for printing paper and writing paper. Taking price aspect into account, hardwood pulp is found rather economical.
Typical features of softwood and softwood pulp:
As its name implies, softwood pulp is soft and contains more resin. Softwood has flat cells in a radial structure. The cell lumen always contains tannin compounds along with resin and is full of air. The major proportion of softwood is cellulose, accounting for 55%, hemicellulose for 11% and lignin at nearly 26%.
It is commonly found in high altitude area, which explains the reason why Canada and Finland becomes one of the largest softwood pulp manufacturers in the world. In addition, these plants are found colorful flexible and waterproof. Ironically, some softwood is harder than some certain kinds of hardwood, meanwhile the hardest hardwood is far harder than any kinds of softwood.
On a detailed basis, we can have a closer look at softwood pulp relating to fiber, paper character, usage and price. In terms of fiber, softwood fiber is rather thin and long. Also, it possesses a high percentage of purity. Softwood pulp; on the other hand; has good flexibility and perfect strength. Besides, softwood pulp is actually an indispensable part of papermaking, playing a crucial part in coated paper, map paper and any other paper industries. For these perfect features serving paper making, softwood pulp price is much more expensive than the other.
Both hardwood and softwood have interesting distinguished features that is worth being taken into consideration. Accordingly, hardwood pulp and softwood pulp possess different characteristics, making them to be used in a different way. No matter how distinctive they are, these two materials are without doubt imperative in paper industry. Finally, we hope that this article will give you a deep understanding of these two materials.