Preparation of mechanical pulps for testing (Revision of T 262 sp-02)

WI 060809.01 T 262 DRAFT NO. 2 TAPPI DATE June 14, 2006 WORKING GROUP CHAIRMAN JW Walkinshaw SUBJECT CATEGORY RELATED METHODS Pulp Properties See Additional Information 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 (Revision of T 262 sp-02) (Underlines indicate changes/revisions since last draft) 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. Approved by the Standard Specific Interest Group for this Test Method TAPPI

T 262 sp-02 Preparation of mechanical pulps for testing / 2 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 development of the pulp's latent properties. 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 strength properties of the development 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 is concerned withensures full development of pulp strength properties and not optical properties (1-3). Optical properties are not usually determined after latency removal.. 4. Apparatus 4.1 Disintegrator 1 (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). 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 the (high consistency) refiners and or pulp grinders. 1 Names of suppliers of testing equipment and materials for this method may be found on the Test Equipment Suppliers list in the set of TAPPI Test Methods, or may be available from the TAPPI Quality and Standards Department.

3 / Preparation of mechanical pulps for testing T 262 sp-02 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 capacity 2 requiring 56 g oven-dry (o.d.) pulp, or 6.2.2 Large, 6.05 L capacity 2 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. 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 (for a brief interval) the pump (for a brief interval) to drain all the pulp slurry from the system. 2 This is in addition to a pump loop capacity of 1.05 L.

T 262 sp-02 Preparation of mechanical pulps for testing / 4 NOTE 2: To avoid damage to the pump, never run the pump for more than 3 s without liquid in it. 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: to be assigned. 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. 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.

5 / Preparation of mechanical pulps for testing T 262 sp-02 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 Director of Quality and Standards. g

WI 060809.01 T 262 DRAFT NO. 1 TAPPI DATE March 28, 2006 WORKING GROUP CHAIRMAN to be assigned SUBJECT CATEGORY RELATED METHODS Pulp Properties See Additional Information 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 (Five-year review of T 262 sp-02) 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. Approved by the Standard Specific Interest Group for this Test Method TAPPI

T 262 sp-02 Preparation of mechanical pulps for testing / 2 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 development of the pulp's latent properties. 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 strength properties of the development 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 is concerned withensures full development of pulp strength properties and not optical properties (1-3). Optical properties are not usually determined after latency removal.. 4. Apparatus 4.1 Disintegrator 1 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). 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 the (high consistency) refiners and or pulp grinders. 1 Names of suppliers of testing equipment and materials for this method may be found on the Test Equipment Suppliers list in the set of TAPPI Test Methods, or may be available from the TAPPI Quality and Standards Department.

3 / Preparation of mechanical pulps for testing T 262 sp-02 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 Whatman No. 30 (or equivalent) filter paper 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 capacity 2 requiring 56 g oven-dry (o.d.) pulp, or 6.2.2 Large, 6.05 L capacity 2 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. 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 (for a brief interval) the pump (for a brief interval) to drain all the pulp slurry from the system. 2 This is in addition to a pump loop capacity of 1.05 L.

T 262 sp-02 Preparation of mechanical pulps for testing / 4 NOTE 2: To avoid damage to the pump, never run the pump for more than 3 s without liquid in it. 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. 8. Keywords Pulp, Mmechanical pulp, Ddisintegration, Llatency, Curl 9. Additional information 9.1 Effective date of issue: to be assigned. 9.2 Related method: CPPAPAPTAC 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. 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, recirculations rate 1/126 min. -1 ; large, 0.20 m diameter, 0.24 m height, capacity 6.05 L, recirculation rate 1/34 min. -1.