Measurement of Cobb absorption value to evaluate the water absorptiveness of paper and board
COBB Tester
Measurement of Cobb absorption value to determine paper sizing efficiency
About Us
What is a COBB Tester?
A COBB Tester for paper is an essential laboratory instrument designed to measure the water absorbency of paper and board. Known as the Cobb sizing test, this method evaluates how much water a specific area of paper absorbs within a given time, expressed as the Cobb value of paper (g/m²).
Technical Parameters
| Sampling Diameter | Ø125mm |
| Sampling error | ±0.2mm |
| Sampling Thickness | (0.1 ~ 2.0) mm |
| Dimension | (250280450) mm LWH |
| COBB Sample Cutter Specification(optional) – Test Area | 100±0.2cm² |
| COBB Sample Cutter Specification(optional) – Water Consumption | 100±5ml |
| COBB Sample Cutter Specification(optional) – Metal Roller Width | 200±0.5mm |
| COBB Sample Cutter Specification(optional) – Metal Roller Weight | 10±0.5kg |
| COBB Sample Cutter Specification(optional) – Dimension | (396315300)mm LWH |
Determination of Cobb absorption value
Standards for Cobb Tester
:
The Cobb paper test is internationally standardized, ensuring repeatable and trusted results
- ISO 535 – Paper and board – Determination of water absorptiveness (Cobb method)
- TAPPI T441 – Water absorptiveness of sized paper and board (Cobb test)
By using a Cobb test apparatus that complies with these standards, manufacturers and laboratories guarantee test accuracy, meeting both customer expectations and regulatory requirements.
Industries That Rely on the Cobb Size Test
The Cobb sizing test is essential in industries where water resistance and surface absorbency directly affect product performance and quality.
01
Paper & Board Manufacturing
Used to evaluate the effectiveness of internal sizing and surface coatings, ensuring consistent water resistance.
01
Packaging & Corrugated Industry
Applied to cartons, labels, and boxes to measure water resistance and maintain structural integrity during storage and transport.
02
Printing & Publishing
Ensures controlled ink absorbency, which is critical for achieving sharp, high-quality prints.
03
Inspection & Certification Laboratories
Conducts standardized testing to verify compliance with ISO 535 and TAPPI T441 international standards.
Cobb tester for packaging materials
Why the COBB Testing Matters？
The water absorbency test for paper is a critical quality control measure that directly influences product performance and usability. If absorbency is not properly controlled,
Paper Weakening
Excessive water absorption can significantly reduce the strength of paper and board, making them prone to tearing, deformation, or structural failure.
Poor Printing Quality
Uncontrolled absorbency often leads to blurred, uneven, or smudged printing, which compromises readability and overall visual presentation.
Packaging Damage & Reduced Shelf Life
In packaging applications, high absorbency can result in cartons or boxes losing rigidity, leading to product damage, reduced shelf life, and costly returns.
By accurately determining the Cobb value of paper using standardized methods, manufacturers can:
- Ensure consistent sizing and coating quality.
- Deliver reliable, high-performance products.
- Minimize customer complaints and claims.
- Meet international standards such as ISO 535 and TAPPI T441.
Ultimately, the water absorbency test helps balance paper’s usability with durability, supporting both manufacturing efficiency and market competitiveness.
Our Advantages
Choosing our COBB Tester for paper means working with a trusted partner in the material testing industry.
01
- Expertise in Paper Testing – Years of experience in manufacturing and supplying Cobb test equipment for global customers.
- High Accuracy & Repeatability – Precision-engineered instruments ensure reliable measurement of the Cobb value of paper.
- Compliance with Standards – Every Cobb test apparatus meets ISO 535 and TAPPI T441 requirements.
- Cost-Effective Solutions – Competitive Cobb tester price without compromising quality.
- Customization Options – From standard Cobb sizing tester to strong Cobb tester, we provide solutions tailored to your industry needs.
With these advantages, we help paper, packaging, and inspection industries achieve accurate results, reduce risks, and maintain consistent product quality.
– CELL INSTRUMENTS
Frequently Asked Questions
1. What is a COBB Tester used for?
A COBB Tester for paper is used to measure the water absorbency of paper and board. The test determines the Cobb value of paper, which reflects how much water a material can absorb in a set time.
2. Which standards does the Cobb sizing test follow?
The Cobb paper test is standardized by ISO 535 and TAPPI T441, ensuring accurate and globally accepted test results.
3. Why is the Cobb value important in the packaging industry?
The Cobb sizing test helps packaging manufacturers evaluate the water resistance of cartons, corrugated boards, and labels, ensuring product durability and compliance with quality requirements.
4. What is the difference between a standard Cobb tester and a strong Cobb tester?
A standard Cobb sizing tester is suitable for general laboratory testing, while a strong Cobb tester is designed with more durable construction for heavy or continuous use in quality control labs.
5. How much does a Cobb tester cost?
The Cobb tester price depends on the model, size, and additional features. We offer competitive pricing along with professional technical support and after-sales service.
Get in touch
No. 5577 Gongyebei Rd, Licheng, Jinan, 250109, Shandong, P.R.C.
marketing@celtec.cn
+86 185 6001 3985
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