Classifications

• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M13/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment
  • D06M13/322—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment with compounds containing nitrogen
  • D06M13/368—Hydroxyalkylamines; Derivatives thereof, e.g. Kritchevsky bases
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M13/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment
  • D06M13/10—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment with compounds containing oxygen
  • D06M13/144—Alcohols; Metal alcoholates
  • D06M13/148—Polyalcohols, e.g. glycerol or glucose
• • 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

Definitions

• This invention relates to cellulosic materials having improved thermal stability, and more particularly to cellulosic materials to be used as insulation in electrical apparatus.
• Cellulose fiber materials tend to deteriorate when subjected to elevated temperatures for extended periods of time resulting in a progressive reduction in their strength until eventually they fracture.
• elevated temperatures may cause the liquid dielectrics to break down into their chemical constituents and the resultant deterioration products may in turn attack the cellulose fiber material.
• the present invention is directed to a cellulose fiber material impregnated with diglycolamine or a combination of diglycolamine and pentaerythritol. Impregnating the cellulose fiber material with either of these additives increases the thermal stability of the cellulose fiber and enables the fibers to Withstand deterioration by the action of heat over extended periods of time. The fibers are not only protected against thermal deterioration, but are also stabilized against attack from decomposition products of transformer oils or other liquid dielectrics. For this reason the cellulose material treated in accordance with the invention is particularly useful in oil-filled transformers or other similar electrical apparatus.
• the cellulose fiber material to be treated can be rayon, paper, cotton, linen or other common cellulosic materials.
• the cellulose material When used as an insulation material in an electrical apparatus, the cellulose material will generally be composed of rag, kraft or manilla paper.
• the active ingredients are preferably applied to the cellulose fibers in the form of an aqueous solution although in some cases the pure active ingredients can be used.
• the fibers can be impregnated in any suitable manner such as by immersing the fibers in a treating solution for a time sufficient to fully impregnate the fibers, or by spraying, brushing, dipping, size pressing or the like. It is important that all of the individual fibers of filaments of the cellulose material be impregnated with the treating solution so that each individual cellulose fiber is able to react with the active ingredients. Impregnation differs from surface coating processes in which only the outer surface of the fibrous material is coated with the active ingredient and the individual fibers on the interior of the material are generally uncoated.
• the impregnation of the cellulose fiber material can be carried out at room temperature or at elevated temperatures up to the boiling point of the solution employed.
• the time of contact between the cellulose fibers and the solution should be sufficient to permit penetration or impregnation of the fibers. Generally a contact time of 15 seconds to 10 minutes is adequate for impregnation, although more rapid impregnation, such as obtained in a size press on a paper machine, or longer periods of impregnation may be employed without adverse effects.
• aqueous treating solution is the most practical, other types of evaporable solvents or carriers can be substituted for Water.
• the cellulose material may be treated with the pure active ingredients, without solution, but for most purposes a treating solution is used.
• the concentration of the active ingredients used in the solution may vary considerably depending on the end use of the cellulose material and the method of application. Although it is somewhat more difficult to achieve the desired impregnation from very dilute solutions as compared to more concentrated solutions, solutions containing as little as 0.5% active ingredients have been used. Generally, solutions containing from 2 to 10% active ingredients are employed with about 7.5% being preferred.
• the weight relationship between the diglycolamine and pentaerythritol is not particularly critical. It has been found that the diglycolamine can be used in the weight ratio of 1:1 to 5:1 with respect to the pentaerythritol.
• the excess solution is removed or drained from the cellulose and the cellulose is either dried at room temperature or at a suitable elevated temperature to evaporate the water or other carrier, if such is used.
• diglycolamine alone it has been found that substantial improvement in thermal stability is obtained when the diglycolamine is present in an amount as small as 1% by weight of the cellulose dry fiber base.
• improvement in the thermal stability has been achieved by using as little as 0.25% by weight of the pentaerythritol in combination with the diglycolamine. This concentration of active ingredients in the dried product corresponds generally to 0.1 to 3.0% by weight of nitrogen.
• the cellulose fibers treated with diglycolamine or with the combination of diglycolamine and pentaerythritol have greatly improved stability enabling the cellulose fiber material to withstand the deteriorating action of heat over extended periods of time.
• the cellulose fiber material is to be used as an insulating material in electrical apparatus and immersed in transformer oil or other dielectrics, it has been found that the treated paper will not discolor or deteriorate the transformer oil.
• a Sample A was prepared by immersing a sheet of kraft paper 8" x 8" and 5 mils thick in an aqueous solution containing 5% diglycolamine and water until the sheet of paper had become thoroughly impregnated. This sheet was allowed to air dry at room temperature. The impregnated sheet of paper was then placed in a glass tube containing insulated copper wire 21" long (16 gauge Formvar) and copper foil (14" X 1" x .002). This paper-copper system was placed in an oven at for 16 hours. During this time a pressure of 0.1 mm. was maintained. The evacuated tube containing this paper was filled under vacuum with an inhibited transformer oil, leaving an air space in the tube of approximately 15% of the total volume.
• the air space was then filled to one atmosphere of pressure with dry air.
• the tube was then sealed 01f with an oxygen gas torch.
• the sealed glass tube was then placed in an oven at 17 C. for 5 days.
• the tube was opened and the physical properties of the paper were determined along with a chemical analysis for water and acid in the oil. These properties are compared with an untreated paper, Sample C, aged under the same conditions.
• a Sample B was prepared by immersing a sheet of kraft paper 8" x 8" andS mils thick in an aqueous solution containing 2.5% diglycolamine and 2.5% pentaerythritol until the sheet was thoroughly impregnated. It was then allowed to dry at room temperature. The impregnated sheet of paper was then placed in a glass tube containing an insulated copper wire 21" long (16 gauge Formvar coated) and copper foil (14" x 1" x 0.002"). This papercopper system was placed in an oven at 135 C. for 16 hours. During this time a pressure of 0.1 mm. was maintained. The evacuated tube containing this paper was filled under vacuum with an inhibited transformer oil leaving an air space in the tube of approximately 15% of the total volume.
• the air space was then filled to one atmosphere pressure with dry air.
• the tube was then sealed off with an oxygen gas torch.
• the sealed tube was then placed in an aging oven at 170 C. for 5 days.
• the paper was removed, its physical properties determined and the oil was analyzed for acid and water. Properties were compared with those of an untreated aged paper, Sample C.
• the tensile strength, toughness, tear strength and burst strength of the Samples A, B and C were compared with the similar properties of untreated and unaged kraft paper.
• the tensile strength of the untreated and aged paper, Sample C was only 70% of the original unaged kraft paper.
• a method of treating cellulose fiber material to increase its physical properties at elevated temperatures comprising the steps of impregnating the cellulose fibers with the combination of diglycolamine and pentaerythritol, said diglycolamine being present in a weight radio of 1:1 to 5:1 with respect to the pentaerythritol.
• a method of increasing the thermal stability of cellulose fiber material to be used in an electrical apparatus comprising the steps of reacting the cellulose fibers with the combination of diglycolamine and pentaerythritol to provide a dry fiber material having a nitrogen content in the range of 0.1 to 3% by weight.
• a method of increasing the thermal stability of cellulose fiber material comprising the steps of impregnating the fibers with an aqueous solution of diglycolamine and pentaerythritol, said diglycolamine being present in a weight ratio of 1:1 to 5 :1 with respect to the pentaerythritol, and thereafter evaporating the water to provide a dried product having from 0.1 to 3% by weight of nitrogen.
• aqueous solution contains from 2 to 10% by weight of said diglycolamine and pentaerythritol.
• a cellulose fiber product having improved physical properties at elevated temperatures comprising a cellulose fiber base impregnated with the combination of diglycolamine and pentaerythritol, said cellulose base containing from 0.1 to 3% by weight of nitrogen.
• a cellulose fiber product having improved physical properties at elevated temperatures comprising a cellulose fiber base impregnated with the combination of diglycolamine and pentaerythritol, said diglycolamine being present in a weight ratio of 1:1 to 5:1 with respect to pentaerythritol, said cellulose base containing from 0.1 to 3% by weight of nitrogen.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Health & Medical Sciences (AREA)
• Emergency Medicine (AREA)
• Paper (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)

Priority Applications (8)

Applications Claiming Priority (1)

Publications (1)

Family

ID=23728009

Family Applications (1)

Country Status (8)

Cited By (2)

Citations (2)

Family Cites Families (2)

• 1965
  • 1965-02-25 US US435342A patent/US3403968A/en not_active Expired - Lifetime
  • 1965-06-01 SE SE7160/65A patent/SE312843B/xx unknown
  • 1965-06-03 GB GB23710/65A patent/GB1060706A/en not_active Expired
  • 1965-06-04 NL NL6507141A patent/NL6507141A/xx unknown
  • 1965-06-05 DE DEM65494A patent/DE1300433B/de active Pending
  • 1965-06-10 FR FR20193A patent/FR1436472A/fr not_active Expired
  • 1965-06-16 LU LU48850A patent/LU48850A1/xx unknown
  • 1965-07-26 BE BE667396D patent/BE667396A/xx unknown

Patent Citations (2)

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