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
  • D21H21/14—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 characterised by function or properties in or on the paper
  • D21H21/30—Luminescent or fluorescent substances, e.g. for optical bleaching

Definitions

• ABSTRACT OF THE DISCLOSURE Paper is optically brightened by coating the surface (A) i n the so-called starch-size process inside the paof the paper with an amount to efiectively optically .per machine, e.g. inasizing press, or
• the phenyl radical is unsubstituted. of'degraded starch.
• wetting agents e.g.
• optical brightening of paper particularly by the surface
• the liquor usable for this purpose as well coating liquor is used which contains, per litre, e.g. 0.2- as, an industrial product, the paper having a content of I 5.0 g. of optical brightener of Formula I, 350-650 g.
• White pigment and, calculated on the amount of white
• white unpigment used 8-30% by weight of binder, (ll-0.6%v sized and, apticularly, sized paper needs optical brightenby Weight of metal binding agents and 0.0l0.03% by ing. This whitening can be performed by treatment of weight of wetting agents.
• the pulp with substantive optical brighteners; advarr- Examples of white pigments are aluminum-magnesitageously however, for the brightening of paper, the so- 40 um silicate (China Clay), CaSO .l0H O (Satinweiss),
• binders are dispersions of synthetic resins brighteners used for the surface coating process do not such as those based on butadiene-styrene, acrylic or methalways meet the increased whitening requirements beacrylic polymers or copolymers, together with degraded cause, generally, they are not sufiiciently active and, in starch, or dispersions of synthetic resins with casein, or high dosages, give the paper an undesirable greenish such dispersions together with degraded starch and tinge. casein.
• metal binding agents are water soluble bene-2,2'-disulph0nic acids of general Formula I, particu- 5 0 polyphosphates or polymetaphosphates, and examples of larly in the form of their soluble salts, are well suited for wetting agents are unsulphated or sulphated higher althe optical brightening of paper including cardboard, in kanol-polyglycol ethers such as those mentioned in the particular in the surface coating process. previous paragraph.
• Ar represents the unsubstituted phenyl
• prefradical or one containing non-colouring substituents e.g. an alkaline coating liquor is used for pigment
• non-colouring substituents are the sulphonic coating.
• the alkaline reaction is advantageously adacid or carboxylic acid group, halogens such as fluorine, ju-sted with ammonium hydroxide or with sodium or chlorine or bromine, low alkyl or alkoxy groups which 5 potassium hydroxides, carbonates, borates, perborates or contain, e.g. 1 to 5 carbon atoms.
• Ar is the mixtures thereof.
• Paper is advantageously coated with these liquors ac- In particular the alkali, alkaline earth or ammonium cording to (A) and (B) in a painting apparatus used for salts, e.g. those derived from ammonia or an alkanolthis purpose.
• salts e.g. those derived from ammonia or an alkanolthis purpose.
• the disodium salt is addition to an improved surface, have a more white and preferred. pleasant appearance.
• EXAMPLE 1 Bn'ghtening in the starch-size process
• the 2 g. of optical brighter of the formula as disodium salt are dissolved in 40 ml. of 90 hot, dis tilled water.
• a degraded starch e.g. Noredux l, Blattmann Co., Wiidenswil, ZH, Switzerland
• 80 g. of a degraded starch e.g. Noredux l, Blattmann Co., Wiidenswil, ZH, Switzerland
• 1000 ml. of 90 hot water are made into a colloid suspension over a period of minutes.
• the brightener solution is then incorporated into the starch solution.
• the solution obtained containing starch and brightener has a pH of 5.5 to 6.0.
• the surface of a sized paper for printing is coated with this liquor in a sizing press and the coated paper is dried at about 50120 in the drier section of the paper machine.
• sized paper instead of sized paper, sized cardboard can be used with the same result.
• the surface of sized paper or cardboard is coated with this liquor in the sizing press or another device.
• a paper coated extraordinarily white is obtained.
• EXAMPLE 3 Brightening of paper pulp 50 g. of an aqueous suspension of bleached sulphite cellulose containing 5 g. of absolutely dry cellulose are mixed with ml. of Water and the mixture is stirred well at room temperature. 0.71 ml. of a sizing solution 1:10 is added and the whole is again well mixed. 5 mg. of the optical brightener described in paragraph 1 of Example 1, dissolved in 10 ml. of water, are then mixed in, the mixture is again stirred Well whereupon the brightener completely draws onto the cellulose fibres. 1.5 ml. of aluminum sulphate solution 1:10 are then added to the pulp which is subsequently diluted with Water to 1000 ml.
• the diluted pulp is made into sheets, pressed and dried. In this way a clear, white sheet is obtained.
• An aqueous coating liquor for the optical brightening of the surface of paper comprising, per liter,
• Weight of Said Pigment (c) 830% by weight of a binder based upon the 3. coating liquor as claimed in claim 2 wherein weight f said Pigment; said binder IS a dispersion of a synthetic resm selected (d) 02 to 06% of a metal binding agent based upon from the group of butadiene-styrene, acrylic or methacrylic polymers and copolymers, and mixtures thereof welght of said plgmentiand (e) 0.01 to 0.3% of wetting agents based upon the with casein.
• a synthetic resm selected (d) 02 to 06% of a metal binding agent based upon from the group of butadiene-styrene, acrylic or methacrylic polymers and copolymers, and mixtures thereof welght of said plgmentiand (e) 0.01 to 0.3% of wetting agents based upon the with casein.
• a method for brightening the surface of paper com- Welght of sald p f prising coating the surface of the paper with an amount
• a method as clalmed 111 (21211111 6 wherein the comto effectively optically brighten said surface of said paper Pound is disodium with an aqueous coating liquor comprising, per liter, azine-2-y1)-amin0]-stilbene-2,2'-disulfonate.

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Citations (4)

• 0
  • NL NL136180D patent/NL136180C/xx active
• 1965
  • 1965-12-10 CH CH1709765A patent/CH455487A/de unknown
• 1966
  • 1966-12-02 US US598640A patent/US3475190A/en not_active Expired - Lifetime
  • 1966-12-09 NL NL6617360A patent/NL6617360A/xx unknown
  • 1966-12-09 BE BE690943D patent/BE690943A/xx unknown
  • 1966-12-09 SE SE16909/66A patent/SE319972B/xx unknown
  • 1966-12-09 ES ES334353A patent/ES334353A1/es not_active Expired
  • 1966-12-09 DE DE19661696203 patent/DE1696203A1/de active Pending
  • 1966-12-09 AT AT1134966A patent/AT268867B/de active
  • 1966-12-09 GB GB55269/66A patent/GB1109537A/en not_active Expired
  • 1966-12-09 FR FR86812A patent/FR1504243A/fr not_active Expired

Patent Citations (4)

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