TAPPI T 262 sp-12

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T 262 sp-12

PROVISIONAL METHOD – 1981

OFFICIAL TEST METHOD – 1989

REVISED – 1991

STANDARD PRACTICE – 1996

REVISED – 2002

REVISED – 2006

REVISED – 2012

The information and data contained in this document were prepared

by a technical committee of the Association. The committee and the

Association assume no liability or responsibility in connection with

the use of such information or data, including but not limited to any

liability under patent, copyright, or trade secret laws. The user is

responsible for determining that this document is the most recent

edition published.

Approved by the Standard Specific Interest Group for this Test Method

TAPPI

CAUTION:

This Test Method may include safety precautions which are believed to be appropriate at the time of publication of the method. The intent of these

is to alert the user of the method to safety issues related to such use. The user is responsible for determining that the safety precautions are complete

and are appropriate to their use of the method, and for ensuring that suitable safety practices have not changed since publication of the method. This

method may require the use, disposal, or both, of chemicals which may present serious health hazards to humans. Procedures for the handling of

such substances are set forth on Material Safety Data Sheets which must be developed by all manufacturers and importers of potentially hazardous

chemicals and maintained by all distributors of potentially hazardous chemicals. Prior to the use of this method, the user must determine whether

any of the chemicals to be used or disposed of are potentially hazardous and, if so, must follow strictly the procedures specified by both the

manufacturer, as well as local, state, and federal authorities for safe use and disposal of these chemicals.

Preparation of mechanical pulps for testing

1. Scope

1.1 This practice describes a procedure for the preparation of mechanical pulps prior to physical testing.

1.2 It is for use with pressure groundwood, refiner mechanical, chemimechanical, thermomechanical, and

chemithermomechanical pulps. It may also be used on any pulp sample taken downstream of the refiners (i.e., screens,

cleaners, reject refiners, etc.). The purpose of this practice is to remove latency (curl) from pulp fibers.

1.3 Hot disintegration of pulps containing lignin may lead to significant loss of brightness. Since brightness

is not significantly changed by the presence of latency in the pulp, this procedure is not recommended for pulps that will

be formed into brightness measuring sheets.

2. Summary

This standard practice involves recirculating stock at about 2% consistency and at 90–95°C for two minutes using a

centrifugal pump connected to a container as a means of processing the fiber prior to physical testing to allow lessening

or removal of the pulp's latency.

3. Significance

3.1 In the production of mechanical pulps with refiners or on grinding stones under pressure, a phenomenon

referred to as “latency” is introduced into the pulp. The action of the refiner twists and rolls the fibers into balls or

nodules of a highly strained state that are not removed by means of conventional disintegration.

3.1.1 When disintegration is done in cold water in accordance with TAPPI T 205 “Forming Handsheets for

Physical Tests of Pulp,” subsequent testing will not show the full development of the strength properties of the pulp.

3.2 Disintegrating the pulp at elevated temperatures and low consistency relaxes the fibers, removing the

latency (fiber twists, rolls, and nodules) referred to in 3.1.

3.2.1 With hot disintegration, the pulp shows complete development of strength properties without further

treatment. The “latency” removal ensures full development of pulp strength properties.

T 262 sp-12 Preparation of mechanical pulps for testing / 2

4. Apparatus

4.1 Disintegrator1

(Domtar-Type) consisting of a pump and a container (see Appendix A).

4.2 Supply of hot water, 90 - 95°C, meeting the requirements of ASTM D 1193 - Type II or distilled or

demineralized water of a conductance of less than 4 μS/m (4 μΩ-1/cm).

4.3 Bucket, of sufficient size to collect stock after disintegration (9.4-L or larger bucket is suitable).

CAUTION: Avoid splashing of hot (90 - 95°C) water in recirculation container.

5. Definitions

Latency, a condition associated with pulp fibers that have internal twists and curvature resulting from the action of

(high consistency) refiners and pulp grinders.

6. Procedure

6.1 Obtain the consistency of the pulp to be hot disintegrated, according to TAPPI T 240 “Consistency

(Concentration) of Pulp Suspensions.”

6.1.1 If the pulp is under 10% consistency and the temperature after dilution can be maintained at 90 to 95°C

there is no need to thicken the pulp. If the pulp is under 10% consistency and the required temperature cannot be

maintained after dilution, then the pulp must be thickened above 10% before proceeding. The pulp is to be thickened

using general purpose ashless filter paper with medium speed and retention and a Buchner funnel (all of the fines must be

retained). Measure the consistency of the thickened pulp prior to the determination of the required amount.

NOTE 1: Thickening the pulp above 10% consistency insures hot disintegration by minimizing the reduction in temperature caused by the

dilution with a low consistency pulp.

6.2 Install the proper size container for the required sample size:

6.2.1 Small, 1.95 L capacity2 requiring 56 g oven-dry (o.d.) pulp, or

6.2.2 Large, 6.05 L capacity2 requiring 136 g oven-dry (o.d.) pulp.

6.3 Calculate the weight of wet pulp required to give either the 56 ± 1 g o.d. or 136 ± 2 g o.d. pulp samples.

6.4 Fill the container with water at 90 - 95°C, and close the lid.

CAUTION: Avoid splashing hot water.

6.5 Start the pump and allow the hot water to recirculate for two minutes. When time has elapsed, drain the

water.

6.5.1 The preceding step warms the container, piping, and pump. If the drained water is less than 90°C repeat

step 6.5.

6.6 Immediately add hot water to the container to fill approximately half full. Add the required amount of wet

pulp to the container, breaking the pulp into small pieces to prevent plugging of the pump.

6.7 Fill the container to the baffle with more hot water.

6.8 Close the lid of the container and fasten securely.

6.9 Turn on-off switch to “on” position.

6.10 Set the pump timer switch to two minutes and allow to run until two minutes has elapsed.

6.11 Place a bucket or pail of appropriate size to collect all the stock and rinse water under the container. Then

open the drain valve, add about 4.0 L of hot water to the container, and run the pump (for a brief interval) to drain all the

pulp slurry from the system.

NOTE 2: To avoid damage to the pump, never run the pump for more than 3 s without liquid in it.

1Names of suppliers of testing equipment and materials for this method may be found on the Test Equipment Suppliers list, available

as part of the CD or printed set of Standards, or on the TAPPI website general Standards page.

2This is in addition to a pump loop capacity of 1.05 L.

3 / Preparation of mechanical pulps for testing T 262 sp-12

6.12 The pulp sample is now suitable for further testing by such methods as TAPPI T 205 and TAPPI T 227

“Freeness of Pulp.”

7. Precision

A statement of precision is not required for this Standard Practice.

8. Keywords

Pulp, Mechanical pulp, Disintegration, Latency, Curl

9. Additional information

9.1 Effective date of issue: November 1, 2012.

9.2 Related method: PAPTAC Standard C.8P; SCAN-M 10:77 method is based on the use of the TAPPI

Standard Disintegrator operated at 85 ± 3°C, at 2% consistency for 30,000 revolutions. Caution: The SCAN Method may

not give the same treatment to the pulp as this method; it is run at a lower temperature and under less severe conditions.

ISO 5263-3 “Pulps – Laboratory Wet Disintegration – Part 3: Disintegration of Mechanical Pulps at ≥ 85°C” is based on

both the TAPPI Standard Disintegrator and the Domtar-Type disintegrator specified in this procedure at a temperature of

greater than 85°C.

9.3 Standard ISO 5263-3 “Pulps – Laboratory wet disintegration – Part 3: Disintegration of pulps at ≥ 85°C”

utilizes the TAPPI Standard Disintegrator operated for 30,000 revolutions at a temperature of ≥85°C for latency removal

of 2500 mL of pulp suspension at 2% consistency.

9.4 The primary revision in the 2012 edition is to provide the information that this procedure is not

recommended for pulps that will be formed into brightness measuring sheets.

Appendix A. Disintegrator

A.1 Stock enters and leaves the container tangentially to avoid cavitation at the pump inlet. Two different

sized containers can be used, depending upon the sample size needed. The small container is 1.95 L capacity, and 56 g of

o.d. pulp is used. For the larger container with a 6.05 L capacity, 136 g o.d. pulp is needed.

A.2 All parts in contact with the pulp must be stainless steel to avoid contamination.

A.3 The cover of the container may be hinged on one end and secured to the other by a thumb tightening

screw or clamp. Steam may be released through a hole 8 mm in diameter in the center of the cover to avoid pressure

buildup. A concentric baffle, one-half the container diameter, avoids splashing the stock through the steam release hole.

A.4 Centrifugal pump: motor, 0.746 kW (1 hp); capacity, 240 L/min. at 3450 rpm; inlet, 38.1 mm (1.5 in.);

outlet, 25.4 mm (1.0 in.).

A.5 Containers: small, 0.10 m diameter, 0.24 m height, capacity 1.95 L, recirculation rate 1/126 min.-1; large,

0.20 m diameter, 0.24 m height, capacity 6.05 L, recirculation rate 1/34 min.-1.

Literature cited

1. Dawson, I. M., MacLellan, A. D. G., Shallhorn, P. M., and Karnis, A., “A Rapid Method for Developing Latent

Properties of Mechanical Pulps,” Pulp and Paper Canada 79 (Convention Issue): TAPPI T 124 (1978).

2. Beath, L. R., Neill, M. T., and Masse, F. A., “Latency in Mechanical Wood Pulps,” Pulp Paper Mag. Can 67

(10): TAPPI T 423 (1966).

3. Jones, H. W., “Occurrence and Removal of Kink and Curl from Mechanical Pulp Fibres as Related to Paper

Properties,” Pulp Paper Mag. Can 67 (6): TAPPI T 283 (1966).

Your comments and suggestions on this procedure are earnestly requested and should be sent to the TAPPI Standards

Department. g

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摘要：

TAPPI T 262 sp-12 是纸浆、纸张和纸板水提取物 pH 测定的标准测试方法，由美国纸浆与造纸工业技术协会（TAPPI）发布。该规范详细描述了通过冷水或热水提取样品后，使用 pH 计测量提取液酸碱度的实验步骤、仪器要求、试剂配制及结果计算方式，适用于质量控制、产品合规性验证及研发分析。它替代了旧版本，并强调在 23±1°C 条件下进行测量以确保数据一致性。掌握 TAPPI T 262 sp-12 有助于造纸行业从业者准确评估纸张的化学稳定性、印刷适性及老化倾向，是纸质材料酸性分析领域

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