Tissue paper, as a daily consumer product, is directly related to user experience and human health. According to GB/T 20810-2018 “Toilet Tissue (including toilet tissue base paper)”, the quality testing of tissue paper covers three major categories: physical properties, safety performance, and hygienic performance. Among them, physical performance testing items include basis weight, thickness, brightness, color, transverse liquid absorption height, tensile index, softness, powder drop rate, ball burst strength, dirt count, and moisture.

Among these indicators, softness and tensile index are the two most critical factors affecting user experience—softness determines hand feel comfort, while tensile index relates to tear resistance during use. Reasonable selection of laboratory testing equipment and establishment of a sound quality inspection system are fundamental work for tissue paper manufacturers to ensure product quality and meet national standards.

Core test indicators and equipment selection

1. Tensile strength and wet tensile strength

Tensile strength is the core indicator for measuring the mechanical properties of tissue paper, reflecting the product’s ability to resist tensile fracture during use. According to GB/T 24328.3-2020, a constant-rate-of-extension tensile strength tester shall be used to determine the tensile strength, elongation at maximum force, and tensile energy absorption of tissue paper and its products. In addition, GB/T 24328.4-2020 further specifies the determination method for wet tensile strength, which is of great significance for evaluating the strength retention ability of tissue paper in a wet state.

Equipment selection recommendation: The Horizontal Tensile Tester is recommended, typical model YT-WL300. This equipment adopts a horizontal structure design, is equipped with a ball screw drive system and servo motor, and the tensile speed can be digitally adjusted within the range of 1–399 mm/min. The instrument is designed according to GB/T 12914 (constant rate of extension method) and can accurately measure parameters such as tensile force, tensile strength, elongation, breaking length, and tensile energy absorption. It is worth noting that the tensile force of tissue paper is usually small, so the resolution of the equipment in the 0–30 N measurement range needs to reach 0.01 N to ensure accurate measurement of small values.

For the Horizontal Tensile Tester, wet strength testing requires immersing the specimen under specific conditions and immediately performing the tensile test to obtain wet tensile strength data.

2. Softness

Softness is the core sensory indicator that distinguishes tissue paper from other paper grades and directly affects the consumer’s user experience. According to GB/T 8942, the softness test requires cutting the specimen into 100 mm × 100 mm, setting the instrument slit width to 5 mm, and measuring at least 6 specimens in both the machine and cross directions, then taking the average.

Equipment selection recommendation: The Softness Tester is recommended, model YT-RRY1000. This instrument is designed according to GB/T 8942 “Determination of paper softness”, with a measurement range of (10–1000) mN, a resolution of 0.1 mN, and an indication error not exceeding ±1%, meeting the testing needs of different standards and materials. The 7-inch IPS high-definition touch screen with a graphical operation interface makes parameter setting and test execution more intuitive and efficient. The instrument has a built-in thermal printer and supports USB and WIFI data export. Test data can be stored locally in 50 groups, facilitating data traceability and analysis.

3. Ball burst strength

Ball burst strength reflects the ability of tissue paper to resist mechanical penetration, and is especially important for evaluating the durability of tissue paper in actual use. The test is based on GB/T 24328.7-2020 and ISO 12625-9-2020, using a spherical test head to puncture the sample and analyze the burst strength of dry and wet samples.

Equipment selection recommendation: The Ball Burst Tester is recommended, typical model YT-BBT5. This equipment uses a high-precision force sensor, with a measurement range of 0–50 N, a resolution of 0.01 N, a spherical measuring head diameter of Φ16 mm, and an indication accuracy of ≤±0.5%.

4. Basis weight and thickness

Basis weight (grammage) is the basic indicator of mass per unit area, directly affecting product cost accounting and strength performance. According to GB/T 451.2, a standard-area specimen (such as 10×10 cm²) is cut and weighed to calculate the mass per unit area. Thickness determination follows GB/T 451.3, using a contact thickness gauge to measure at multiple points under 10 kPa pressure.

Equipment selection recommendation: For basis weight determination, a circular basis weight cutter can be used together with a high-precision electronic balance (accuracy 0.001 g). For thickness determination, the YT-H10E Tissue Paper Electronic Thickness Tester is recommended to ensure stable readings under standard pressure. For the bulk thickness and apparent bulk density testing of tissue paper, GB/T 24328.2 shall be followed.

5. Brightness and color

Brightness is an important indicator of the appearance quality of tissue paper, while color reflects the product’s color consistency and color difference control level. According to standard methods, the brightness and color parameters of the specimen need to be measured under D65 standard illuminant.

Equipment selection recommendation: The Brightness and Color Tester is recommended, preferably a spectrophotometer-type instrument conforming to ISO standards, which can simultaneously measure optical properties such as ISO brightness, color, color difference, fluorescence, and opacity. For tissue paper products, special attention should be paid to the fluorescent whitening agent detection function to ensure the product meets the safety requirements for migratable fluorescent substances.

6. Transverse liquid absorption height

Transverse liquid absorption height reflects the liquid absorption capacity of tissue paper and is an important indicator for evaluating product performance. The test method is to vertically immerse the specimen in liquid and measure the height to which the liquid rises along the specimen within a certain time.

Equipment selection recommendation: The Klemm Capillary Rise Tester is recommended. Ensure that the test environment temperature and liquid temperature remain constant to ensure repeatability of results. The equipment should have an automatic timing function to reduce manual operation errors.

7. Dirt count

Dirt count reflects the cleanliness of the paper surface. According to GB/T 1541-2013, both sides of a single-layer specimen need to be inspected, with a test area of not less than 0.5 m², and the number of dirt particles counted.

Equipment selection recommendation: The traditional method uses a dirt count inspection table together with standard dirt count charts for visual comparison. For modern solutions, an automatic dirt count measurement system based on machine vision is recommended. This type of system acquires sample images through a high-resolution scanner and uses image analysis algorithms to automatically identify, classify, and count dirt particles, greatly improving detection efficiency and consistency of results.

8. Moisture and powder drop rate

Moisture determination follows GB/T 462-2023, using the oven drying method to determine the moisture content in paper and paperboard. It is recommended to use an electric thermostatic blast drying oven together with an electronic balance, ensuring temperature control within the range specified by the standard.

Powder drop rate is a unique test item for tissue paper, reflecting the degree of fiber and filler shedding during use. The YT-DFL Tissue Powder Drop Rate Tester is designed according to the GB/T 20810 standard. Its working principle is to clamp the specimen on the specimen chuck, and the swing arm reciprocates to the specified time. The powder drop rate is calculated by weighing the mass difference of the specimen before and after swinging.