Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
  • D21H21/02—Agents for preventing deposition on the paper mill equipment, e.g. pitch or slime control
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/03—Non-macromolecular organic compounds
  • D21H17/05—Non-macromolecular organic compounds containing elements other than carbon and hydrogen only
  • D21H17/07—Nitrogen-containing compounds
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S162/00—Paper making and fiber liberation
  • Y10S162/04—Pitch control
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S210/00—Liquid purification or separation
  • Y10S210/928—Paper mill waste, e.g. white water, black liquor treated
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S516/00—Colloid systems and wetting agents; subcombinations thereof; processes of
  • Y10S516/01—Wetting, emulsifying, dispersing, or stabilizing agents
  • Y10S516/07—Organic amine, amide, or n-base containing

Definitions

• pitch normally are sticky, tacky aggregations of the small globules of the natural resins freed from the wood cells in the pulping processes.
• Other components of the paper furnish in addition to fibers such as fillers, pigments, sizing materials, defoamers, wet strength resins, retention aids, fiber bonding agents, etc., may be entrained or otherwise become part of the socalled pitch deposits which accumulate on the surfaces of screens, chests, pipes, the wire of the paper machines on which the sheet of the paper is formed, in the wet felts, on the presses, and in the dryers and calender stacks. Aggregations of pitch and other materials in the paper furnish also may be carried along with the furnish and grow in size as they move along in the papermaking process.
• Surfactants and dispersing agents of various types also have been used as well as emulsifiers, protective colloids and adsorbents, such as very finely divided talc and china clay.
• emulsifiers such as very finely divided talc and china clay.
• protective colloids such as very finely divided talc and china clay.
• adsorbents such as very finely divided talc and china clay.
• troubles caused by the presence of pitch are inhibited by adding to the aqueous fluids of the pulp and papermaking systems a composition comprising N,N- di-methylamides of straight-chain unsaturated carboxylic acids.
• Suitable N,N-dirnethylamides of straight-chain carboxylic acids are those prepared from carboxylic acids containing 18 carbon atoms. The acids are further characterized by having at least one carbon to carbon double bond. Specific acids classified within this category inul ude: oleic, linoleic, linolenic, ricinoleic, and mixtures thereof. Also suitable are the mixed acids found in tall, castor, corn, cottonseed, linseed, olive, peanut, rapeseed, safflower, sesame, and soybean oils. A mixture of carboxylic acids particularly suitable for use in our invention is that available commercially as tall oil fatty acids under the trademark Unitol ACD. A typical analysis of this product is as follows:
• the amount of the pitch control composition of our invention to be added to the pulp and paper systems is dependent upon the amount of pitch present in the pulp or paper furnish flowing through the systems, to some extent where the inhibitor is added to the system and the amount of white water containing inhibitor that is lost between the point of addition and the end of the system throughout which pitch control is desired. In general, it has been found adequate to maintain a concentration of the pitch control composition of about 0.2 to 20 parts of the inhibitor per million parts of pulp and water or paper furnish and water based on the point of maximum dilution in the system with the preferred range of use from 0.5 to parts per million of the composition. It is understood, of course, that larger quantities of the composition may be used, but such is not generally desirable because costs may be increased thereby without commensurate additional beneficial results.
• the pitch particles are maintained in a dispersed state and do not grow in size or adhere to the surfaces of equipment in such a way and to such an extent as to cause the problems encountered when the composition is not added to the pulp or paper systems.
• Example 1 In a paper machine system making 27.5 pound glassine from bleached semichemical, bleached kraft and unbleached sulfite pulps and repulped broke, in which the pH of the aqueous fluids ranged from about 4.3 to 6.2 and the temperature from 77 to 124 F., considerable pitch trouble was encountered after a short period of operation with no pitch control composition in the system. This was evidenced particularly by sticking on the second press.
• Example 2 In a paper machine system making 20.0 pound soap wrap from bleached semichemical and bleached kraft pulps, in which the pH of the aqueous fluids ranged from 4.6 to 6.5 and the temperature from 77 to 142 B, there was no evidence of characteristic pitch problems during the entire run while the N,N-dimethylamides of tall oil fatty acids were added to the paper machine system at the suction side of the fan pump at a rate of 0.63 pound per ton of paper produced. This rate is equivalent to a concentration of about 1.5 parts of the pitch control composition per million parts of the furnish at the wire of the paper machine.
• Example 3 In the production of 35.0 pound greaseproof from bleached sulfite and bleached kraft pulps in a paper machine system in which the pH of the aqueous fluids ranged from 3.8 to 5.2 and the temperature from 60 to 138 F., a large amount of pitch deposited upon the wire of the paper machine within a period of several hours when no pitch control composition was added to the systern. The amount of pitch on the wire required stopping the machine to clean the wire with steam.
• the N,N-dimethylamides of tall oil fatty acids were added to the system at the suction side of the fan pump delivering paper furnish to the headbox of the paper machine at a rate varying from 0.47 to 0.51 pound per ton of paper produced, which was equivalent to a concentration of about 1.2 parts of the pitch control composition per million parts of the furnish at the wire of the paper machine. No pitch troubles were encountered during the second run while the pitch inhibitor was being added even after 24 hours of operation.
• Example 4 In a paper machine system making diflFerent grades of unbleached kraft board, in which the pH of the aqueous fluids ranged from 4.5 to 6.0 with an average temperature of about F., deposits accumulated in the secondary headbox and these seemed to act as binder for fiber. The total accumulation on the slice of the headbox then would break loose periodically and cause the sheet to break. This had been so severe that the machine had been stopped and the secondary headbox washed as often as once per day in addition to the lost time from breaks. Analysis of the deposit showed that it contained pitch. The subsequent addition of about 1.0 part of N,N-dimethylamides of tall oil fatty acids per million parts of the furnish to the suction side of the fan pump serving the secondary headbox was sufficient to overcome the problem.
• a pitch control process which comprises adding to the aqueous fluids of a pulp or papermaking system a composition consisting essentially of an N,N-dimethylamide of a straight'chain carboxylic acid, characterized in that said acid contains 18 carbon atoms and at least one carbon to carbon double bond, at a rate which provides a concentration of said amide of at least 0.2 ppm. in said aqueous fluids.
• straight-chain carboxylic acid is a mixture of straight-chain carboxylic acids containing 18 carbon atoms and at least one carbon to carbon double bond.
• N,N-dimethyl- N,N-dirnethyl- N,N-dimethylamide is N,N-dimethylricinoleamicle.

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Citations (2)

• 0
  • NL NL302971D patent/NL302971A/xx unknown
• 1963
  • 1963-04-29 US US276199A patent/US3274050A/en not_active Expired - Lifetime
  • 1963-06-19 DK DK291463AA patent/DK104721C/da active
  • 1963-07-16 FI FI1403/63A patent/FI40966B/fi active
  • 1963-07-19 CH CH906963A patent/CH429423A/de unknown
  • 1963-07-24 AT AT592063A patent/AT244738B/de active
  • 1963-07-25 DE DEB72854A patent/DE1233710B/de active Pending
  • 1963-08-16 ES ES290881A patent/ES290881A1/es not_active Expired
  • 1963-08-21 GB GB33163/63A patent/GB973556A/en not_active Expired
  • 1963-12-03 BE BE640747A patent/BE640747A/xx unknown

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