Difference Between Softwood & Hardwood Pulp

Do you know that wood proves over 93% of the fibers of pulp making? Yes, the main and primary source of fiber for pulp making and paper manufacturing has been Wood. The remaining fiber comes from non-wood materials like bamboo, jute, wheat straw, sugarcane, etc. 

Here, wood is categorized into two, softwood and hardwood, and both of them can be used in paper and pulp making. Therefore, the wood pulp is categorized into softwood and hardwood pulp based on pulp making. 

Let us know in the following section, what these are and how they differentiate. 

Difference Between Softwood & Hardwood Pulp

1. Softwood Pulp

• Softwood or needle wood is also called Gymnospermae wood. These are more homogeneous than angiosperms or hardwood. 
• Softwood pulp is made from softwood, which is soft, strong, and made of a higher amount of resin. 
• Its vertical structure is majorly formed of conical cells, while the horizontal system is made of narrow ray cells. 
• Examples of softwood include red pine, spruce, larch, pinus massoniana, spruce, etc.

2. Hardwood Pulp

• Hardwood is also called angiosperms.
• It usually features a large size and heavyweight. 
• Hardwood can be quickly wrapped, and cracked, however, difficult to process.
• The fibers of hardwood are generally short in length i.e. 1 mm. Plus the length-width ratio is less than 60 times. 
• The composition of hardwood consists:
  • Wood cellulose- 43-70%
  • Duct- 20-40%
  • Wood ray- 10-20%
  • Parenchymal cell- 2-13%
• Examples of hardwood are poplar, maple, birch, basswood, etc. 
• The paper made from hardwood pulp is low in strength and loose, however, high absorption ability and high opaqueness. Manufacturers can easily measure the porosity/absorbency of paper with Porosity test equipment. 

• The characteristics of hardwood make it ideal for manufacturing printing paper. 

3. Comparison Between Softwood And Hardwood Pulp

• Nature of Fibers

The fibers of softwood are lengthy, thin, and clean. They usually contain fewer impurities/pollutants. 

While hardwood fibers are short in size, thick, and contain higher impurities.

• Content of Lignin

Softwood contains 20-40% more lignin content than hardwood. This makes it easier for hardwood to make pulp and get bleached. It even consumes less amount of alkaline.

• Density

Wood density is highly responsible for the quality of paper pulp. Hardwood has a higher density than softwood. This is why it requires a slower beating rate and offers high tensile strength and higher bulk quality.  

• Price Of Pulp

The price of softwood pulp is much higher than that of hardwood pulp. 

• Use

Softwood pulp is used for making text paper, map paper, coated paper, and other technical and industrial papers. 

Hardwood pulp is mixed with softwood pulp due to its lower quality and is then used to manufacture coated paper, offset paper, printing, and writing papers too.

• Quality & Characteristics Of Paper

Paper made from softwood pulp has high flexibility, high folding strength and tensile strength, and printing ability. On the other hand, hardwood pulp paper is loose, highly absorbent, opaque, stiff, and thick. Know the printability of paper with Printability Tester by UECIN.

Conclusion

Before making paper, it is essential to know in-depth the source of paper pulp and its characteristics. Plus, testing the paper before use is another necessary step. UECIN understands these needs and offers a wide range of paper testing equipment to manufacturers and other industries. Get in touch to know more.