SE183178C1

SE183178C1 -

Info

Publication number: SE183178C1
Authority: SE
Publication date: 1963-01-01

Description

Uppfinnare: B T Hofreiter, G E Hamerstrand och C L Mehltretter Prioritet begard !ran den 10 december 1959 (USA) Foreliggande uppfinning avser framstallning av hOggradigt vat- och torrstarka papper och andra hopfiltade cellulosafibermaterial, t. ex. papp, formade foremal av pappersmassa och liknande, samt avser sarskilt ett forfarande for framstallning av papper, varvid en speciell komposition anvandes som tillsats i hollandaren eller fore arkbildningen vid pappersframstallning Papper med hog tillfallig vatstyrka kan framstallas genom att limma pappersark med dialdehydstarkelse, som dispergerats i vatten genom be-handling med borax eller bisulfit. Harvid ledes den bildade banan eller arket genom en vattenhaltig dispersion eller losning av den polymera dialdehyden, nedan kallad dialdehydstdrkelse, for impregnering ddr med i en mangd av minst 1,8 % for att bibringa det slutligen erhallna arket vitstyrka. En fordel med denna typ av pappersbehandling for att astadkomma vatstyrka dr, att den polymera dialdehydens molekylstorlek icke ãr kritisk. Dialdehydstarkelse, som dispergerats eller losts i vatten medelst borax eller utspatt alkali, vilket i hog grad nedbryter polymeren, och medelst sadana sura amnen som natriumbisulfit, som kan anvandas f Or att framkalla begransad nedbrytning av polymeren kunna likaledes anvandas for detta Andamd.l. En nackdel fir, att relativt stora mangder dialdehydstarkelse maste absorberas av arket for erhallande av god vatstyrka. Inventors: B T Hofreiter, G E Hamerstrand and C L Mehltretter Priority Declaration of December 10, 1959 (USA) The present invention relates to the production of highly waterproof and dry paper and other tangled cellulosic fibrous materials, e.g. cardboard, molded articles of pulp and the like, and in particular a process for the production of paper, wherein a special composition is used as an additive in the Dutch or for the formation of paper in papermaking. Paper with high temporary water strength can be produced by gluing dialdehyde starch paper sheets dispersed in water by treatment with borax or bisulfite. The resulting web or sheet is then passed through an aqueous dispersion or solution of the polymeric dialdehyde, hereinafter referred to as dialdehyde starch, for impregnation therein in an amount of at least 1.8% to impart white strength to the finally obtained sheet. An advantage of this type of paper treatment for achieving water strength is that the molecular size of the polymeric dialdehyde is not critical. Dialdehyde starch, which is dispersed or dissolved in water by means of borax or spattered alkali, which greatly degrades the polymer, and by means of such acidic substances as sodium bisulfite, which can be used to induce limited decomposition of the polymer can also be used for this purpose. A disadvantage is that relatively large amounts of dialdehyde starch must be absorbed by the sheet in order to obtain good water strength.

Nackdelarna med limningen (tub-sizing) aro i allmanhet tre stycken: (1) De fiesta pappersbruk ha ingen apparatur for limning genom doppning eller avpressning, (2) stora mangder vatten, som absorberats av arket, maste avdrivas under torksteget, vilket är dyrbart, (3) svaga vata banor eller ark, t. ex. handdukar kunna icke ledas genom ett limningsbad utan bristning. The disadvantages of gluing (tub-sizing) are generally threefold: (1) Most paper mills have no apparatus for gluing by dipping or squeezing, (2) large amounts of water absorbed by the sheet must be evaporated during the drying step, which is expensive , (3) weak wet webs or sheets, e.g. towels can not be passed through a gluing bath without rupture.

Meller har visat (Tappi 41, 684-686 (1958); fig. 1, sid. 681) att perjodatoxiderad starkelse eller dialdehydstarkelse framkallar vatstyrka hos papper, da den anvandes som tillsats i hollandaren till blekt sulfatmassa. De erhallna vatstyrkevardena aro emellertid for laga for praktiskt bruk vid anvandning av dialdehydstarkelse i relativt hoga halter av 5-10 % pa fibervikten, sasom kommer att framga av det foljande. Metier fann ingen bkning av torrstyrkan hos dialdehydstdrkelsebehandlat 'Dapper; torrstyrkan befanns ndmligen vara lagre an for icke-behandlat papper. Den perjodatoxiderade oxistarkelsens dispersionsgrad i kokande vatten angavs icke av Meller, men avsevard nedbrytning av den polymera dialdehyden skulle ha agt rum, om kokningen fatt fortsatta under flera timmar, vilket skulle ge en lag retention i fibern. A andra sidan skulle en kort be-handling med kokande vatten lamna kvar en stor mangd hoggradigt polymer dialdehyd, vilken icke skulle ha dispergerats tillrackligt och blivit daligt fordelad pa fibern. Meller has shown (Tappi 41, 684-686 (1958); Fig. 1, p. 681) that periodate oxidized starch or dialdehyde starch produces water strength in paper, as it was used as an additive in the Dutch to bleached sulphate pulp. However, the water strength values obtained are suitable for practical use in the use of dialdehyde starch at relatively high levels of 5-10% by weight of the fiber, as will be seen below. Metier found no increase in dry strength of dialdehyde starch treated 'Dapper; the dry strength was found to be lower than for untreated paper. The degree of dispersion of the periodate oxidized oxy starch in boiling water was not stated by Meller, but considerable degradation of the polymeric dialdehyde would have taken place if boiling had been continued for several hours, which would have given a low retention in the fiber. On the other hand, a short treatment with boiling water would leave a large amount of highly polymeric dialdehyde, which would not have been sufficiently dispersed and poorly distributed on the fiber.

Det huvudsakliga andamalet med uppfinningen ãr att framstalla en dialdehydstarkelse, vars molekylstruktur Si sadan, att produkten i egenskap av tillsatsamne till vattensuspensioner av hydratiserad eller icke hydratiserad pappersmassa i hollandaren, ramaterialbehallaren (stock chest), nivakdrlet eller vid nogot annat ldmpligt stdlle fore pappersbildningssteget, bibringas fOrmãga att astadkomma vatstyrka eller Oka torrstyrkan hos det fardiga papperet. The main object of the invention is to produce a dialdehyde starch, the molecular structure of which is such that the product, as an additive to aqueous suspensions of hydrated or non-hydrated pulp in the Dutch, stock chest, level box or other exemplary paper, Ability to achieve water strength or Increase the dry strength of the finished paper.

Det har befunnits, att detta andamal kan uppfyllas genom att cellulosafibrerna behandlas med polymera dialdehyder, framstallda genom 70100 % oxidation av starkelse med perjodat och vilkas molekylstorlek minskats genom reglerad hydrolys eller nedbrytning. Ovan angivna dialdehydstarkelser aro kanda for att, innan de hydrolyseras eller nedbrytas, existera i hoggradigt polymer form med molekylvikter av storleksordningen 40 miljoner och kunna icke anvandas vid uppfinningens utovning. Under reglerad hydrolys eller nedbrytning av dialdehydstarkelse erhallas 2— — polymera dialdehyder, av vilka over 80 % liar en molekylvikt mellan granserna 300 000 och 5 000 000 och som kunna anvandas vid foreligliggande uppfinning, sasom kommer att framga av nedanstaende. It has been found that this andamal can be fulfilled by treating the cellulose fibers with polymeric dialdehydes, produced by 70100% oxidation of starch with periodate and whose molecular size is reduced by controlled hydrolysis or degradation. The above-mentioned dialdehyde starches are known to exist, before being hydrolyzed or degraded, in highly polymeric form with molecular weights of the order of 40 million and cannot be used in the practice of the invention. During controlled hydrolysis or degradation of dialdehyde starch, 2 - - polymeric dialdehydes are obtained, of which over 80% have a molecular weight between the limits of 300,000 and 5,000,000 and which can be used in the present invention, as will be apparent from the following.

Monomera dialdehyder, t. ex. glyoxal och glutaraldehyd samt alkalinedbruten dialdehydstarkelse och dialdehydstarkelse, som kraftigt nedbrutits genom andra metoder, for bildning av en storre mangd lagmolekylara polymera produkter, duga joke vid framstallning av vatstarkt papper enligt uppfinningen. Monomera dialdehydes, e.g. glyoxal and glutaraldehyde as well as alkali-degraded dialdehyde starch and dialdehyde starch, which have been greatly degraded by other methods to form a larger variety of low molecular weight polymeric products, are sufficient jokes in the production of waterproof paper according to the invention.

Vid framstallning av polymera dialdehyder, lampliga att anva.nda som tillsats i holldndaren, framstdlles forst dialdehydstarkelse pa kant satt genom att 0,7-1 mol perjodat bringas att reagera med 1 mol starkelser, vilket uttryck innefattar alla cereala starkelse, t. ex majsstarkelse och vetestarkelse samt aven rotfruktsstarkelser, innefattande potatisstarkelse. Den vattenolosliga dialdehydstarkelsen isoleras genom filtrering eller centrifugering och tvattas vasentligen fri fran forbrukat oxidationsmedel. Den kan torkas eller anvandas i vat tillstand for nedbrytning till det molekylvilitomrade, som passar for uppfinningens andamal. Vid hydrolysen eller nedbrytningen uppslammas 3 delar dialdehydstarkelse, pa. torrbasis, i 96,55 delar vatten, innehallande 0,45 delar natriumbisulfit, och varmes 40 minuter vid 92° C, tills en likformig dispersion ernas, vilken vid kylning far en viskositet av ca 470 op vid 25° C. (60 vary/min. spindelhastighet) Brookfield viskosimeter. In the preparation of polymeric dialdehydes, suitable for use as an additive in the holder, first dialdehyde starch is prepared by setting by reacting 0.7-1 moles of periodate with 1 mole of starches, which expression includes all cereal starches, e.g. corn starch. and wheat starch as well as root vegetable starches, including potato starch. The water-insoluble dialdehyde starch is isolated by filtration or centrifugation and washed substantially free of spent oxidizing agent. It can be dried or used in a wet state for degradation to the molecular weight range suitable for the purposes of the invention. During hydrolysis or decomposition, 3 parts of dialdehyde starch are suspended, pa. dry base, in 96.55 parts of water, containing 0.45 parts of sodium bisulfite, and heated for 40 minutes at 92 ° C, until a uniform dispersion is obtained, which on cooling has a viscosity of about 470 op at 25 ° C. min spindle speed) Brookfield viscometer.

Da dialdehydstdrkelse varmes 30, 40,70 och 90 minuter under ovan angivna betingelser, bli de farglosa dispersionernas viskositeter 1620, 470, 9,8 resp. 4,0 op vid 25° C. Papper med hog vatstyrka erhalles vid anvandande av dispersioner inom detta viskositetsomrade. Ultracentrifuge-rings- och ljusspridningsmatningar tyda pa att sadana dispersioner ha molekylvikter mom granserna 300 000-5 000 000. When dialdehyde starch is heated for 30, 40, 70 and 90 minutes under the above conditions, the colorless dispersions of the colorless dispersions become 1620, 470, 9.8 and 4.0 op at 25 ° C. High water strength paper is obtained using dispersions within this viscosity range. Ultracentrifugation and light scattering feeds indicate that such dispersions have molecular weights between the limits of 300,000-5,000,000.

Forfarandet beskrives i forsta hand for att askadliggora uppfinningen, och det dr ovasentligt, hur dialdehydstdrkelsen nedbrytes for bildning av den. polymera dialdehyden med molekylviktsomradet enligt uppfinningen. De polymera dialdehyderna kunna Avon isoleras fran hydrolysaten genom fallning med lampliga losningsmedel eller ocksa kunna de vattenhaltiga dispersionerna indunstas till torrhet fore anvandningen enligt uppfinningen. The process is described primarily to illustrate the invention, and it is immaterial how the dialdehyde starch is degraded to form it. polymeric dialdehyde with the molecular weight range according to the invention. The polymeric dialdehydes can Avon be isolated from the hydrolysates by precipitation with suitable solvents or the aqueous dispersions can be evaporated to dryness before use according to the invention.

- Kvavehaltiga hartser, t. ex. modifierade urinamneformaldehyd- och melamin-formaldehyd-- kondensationsprodukter, anvdndas for narvarande i stor utstrackning for att Ora papper vatstarkt. Del ror sig hdrvid cm katjoniska kolloidala aggregat, vilka kvarhallas av den negativt laddade tellulosafibern genom elektrostatiska krafter. Deras anvandbarhet som medel fOr alt astadkomma permanent vatstyrka beror emellertid pa deras ytterligare polymerisation eller hardning i papperet under varmtorkningssteget och under de fardiga pappersrullarnas lagring. Nitrogen-containing resins, e.g. modified urinary formaldehyde and melamine-formaldehyde condensation products, are currently widely used to make paper water resistant. Part moves along with cationic colloidal aggregates, which are retained by the negatively charged tellulose fiber by electrostatic forces. However, their usefulness as a means of achieving permanent water strength depends on their further polymerization or curing in the paper during the heat drying step and during the storage of the finished paper rolls.

En vdsentlig skillnad mellan fOreliggande uppfinning och teknikens standpunkt Ar, att de for cellulosafibrernas behandling anvanda polymera dialdehyderna joke innehalla kvave och joke aro hartsbildande. Efter upptagning i cellulosafibrerna reagera de med cellulosan under sura betingelser. Hur de polymera dialdehyderna enligt uppfinningen samverka med cellulosafibern i papperet Ar joke fullt klarlagt, med det antages, att det Ar fraga om en acetalbildning for astadkommande av tvdrbindningar i cellulosan, vilka gra papperet mera bestandigt gentemot sonderfall vid vdtning med vatten. Lufttorkning vid rumstemperatur ger omkring samma vatstyrka som torkning vid f Orhojda temperaturer i flera minuter, sa. att det ar into nodvandigt med flagon langre hardningsperiod, sasom fallet Ar med katjoniskt melaminformaldehydharts. En ytterligare fordel dr, att vattenhaltiga dispersioner, innehallande polymer dialdehyd, Arc farglosa i motsats till de fargade kvavehaltiga hartserna och dro mera lampliga att anvanda i vita pappersprodukter. A significant difference between the present invention and the state of the art is that the polymeric dialdehydes used for the treatment of cellulosic fibers joke contain nitrogen and joke aro resin-forming. After uptake into the cellulosic fibers, they react with the cellulose under acidic conditions. How the polymeric dialdehydes according to the invention interact with the cellulose fiber in the paper is fully explained, but it is assumed that it is an acetal formation for the formation of double bonds in the cellulose, which make the paper more resistant to special precipitation when wet with water. Air drying at room temperature gives about the same water strength as drying at elevated temperatures for several minutes, he said. that it is necessary to have a longer curing period, as in the case of cationic melamine formaldehyde resin. An additional advantage is that aqueous dispersions, containing polymeric dialdehyde, Arc are colorless in contrast to the colored nitrogen-containing resins and are more suitable for use in white paper products.

Den vatstyrka, som uppnas vid anvdndande av dialdehydstarkelser, anses vara av tillfallig natur, da. den minskas, dd. det behandlade papperet doppas i vatten under ldngre tidsperioder. Vatstyrkan dr emellertid mer An tillracklig fOr sadana tillampningar som pappershanddukar, servetter och liknande. En fordel med den tillfalliga vatstyrkan dr, att behandlat anvant papper och avfall fran pappersbruk latt kunna anvandas pa nytt genom enkel sonderdelning under kort lid med utspatt alkali, utspadd syra eller t. o. m. varmvatten for avldgsnande av de polymera dialdehyderna. The water strength obtained by using dialdehyde starches is considered to be of a random nature, da. it is reduced, dd. the treated paper is dipped in water for longer periods of time. However, the water strength is more than sufficient for such applications as paper towels, napkins and the like. An advantage of the temporary water strength is that treated used paper and waste from paper mills can be reused by simple probe division for a short time with diluted alkali, diluted acid or even hot water to remove the polymeric dialdehydes.

Forbattrad slitstyrka i torrt tillstand och sprangstyrka i torrt tillstand uppnas dven vid upp- finningen. Samtliga dessa fordelar,vilka erhallas genom att anbringa partiellt nedbruten dialdehydstdrkelse pa papper eller pappersfibrer enligt uppfinningen, utgora ett betydelsefullt tekniskt framsteg vid framstallning av vatstarkt och forbattrat torrstarkt papper. Improved abrasion resistance in the dry state and burst strength in the dry state are achieved at the invention. All these advantages, which are obtained by applying partially degraded dialdehyde starch to paper or paper fibers according to the invention, constitute a significant technical advance in the production of waterproof and improved dry strength paper.

Det Ar ldmpligast att anbringa de polymera dialdehyderna enligt uppfinningen pa cellulosafibrerna i hollandaren eller fore arkbildningen i narvaro av alun och sma mangder salter, t. ex. natrium-, kalcium- och magnesiumbikarbonater och liknande, vilka i allmanhet finnas narvarande i det tillfOrda vattnet. Den vattenhaltiga dispersionen av den nedbrutna dialdehydstarkelsen med ldmplig molekylviktsfordelning sattes foljaktligen till pappersutgangsmaterialet i vattenledningsvatten i hollandaren, ramaterialbehallaren, jordankvarnen, flaktpumpen, nivakarlet eller vid nagon punkt fore pappersviran, varefter aluminiumsulf at tillsattes, sa att pH far ett varde mellan 4 och 5, foretradesvis 4,5. Mineralsyror, t. ex. saltsyra, kunna aven tillsattas fOr att reglera det sura saltets surhetsgrad. De behandlade cellulosafibrerna ledas ddrefter Over silarna i en Fourdriniermaskin och overforas till papper pa brukligt satt. Genom att fibrerna fa absorbera 0,3 —1 % av de polymera dialdehyderna, raknat pa pappersarkets torrvikt, uppnas den avsedda vat- - -3 styrkan och forbattrade torrstyrkan hos papperet. It is most convenient to apply the polymeric dialdehydes of the invention to the cellulosic fibers in the Dutch or pre-sheet formation in the presence of alum and small amounts of salts, e.g. sodium, calcium and magnesium bicarbonates and the like, which are generally present in the supplied water. The aqueous dispersion of the degraded dialdehyde starch with an exemplary molecular weight distribution was consequently added to the paper feedstock in tap water in the Dutch, the raw material container, the soil mill, the flat pump, the level vessel or at some point in front of the paper wire, after which aluminum sulfide 4.5. Mineral acids, e.g. hydrochloric acid, may also be added to control the acidity of the acid salt. The treated cellulosic fibers are then passed over the sieves in a Fourdrinier machine and transferred to paper in the usual manner. By allowing the fibers to absorb 0.3-1% of the polymeric dialdehydes, based on the dry weight of the paper sheet, the intended water strength is achieved and the dry strength of the paper is improved.

Uppfinningen skall i det foljande beskrivas under hanvisning till fOljande exempel. The invention will be described in the following with reference to the following examples.

Exempel 1. Polymera dialdehyder, framstallda ur till 95 % perjodatoxiderad starkelse under varierande nedbrylningsbetingelser, anbringades i vattenhaltig dispersion vid olika koncentrationer pa blekt och icke blekt pappersmassa i suspension i vattenledningsvatten under tillsats av aluminiumsulfat, varefter det behandlade ramaterialet overfordes till papper i en laboratoriemaskin for pappershanddukar och provades pa slitstyrka i torrt och vatt tillstand. Slitstyrkan finns angiven i kp/cm. Om joke annat sages, anges slitstyrkan i vatt tillstand efter 30 minuter doppning vid 23° C i destillerat vatten. Example 1. Polymeric dialdehydes, prepared from 95% periodate oxidized starch under varying degradation conditions, were applied in aqueous dispersion at various concentrations of bleached and unbleached pulp in suspension in aqueous water with the addition of aluminum sulfate, after which the treated raw material was transferred to paper in a laboratory. paper towels and tested for durability in dry and wet condition. The wear resistance is stated in kp / cm. If the joke is otherwise stated, the wear resistance in the water state is stated after 30 minutes of dipping at 23 ° C in distilled water.

Blekt sulfatmassa, som malts till en draneringsformaga (freeness) av 700 ml enligt SchopperRiegler, anvandes. 340 ml av en vattenuppslamning (300 delar per miljon total karbonathardhet) innehallande 1,2 g (torr basis) av massan install-des pa pH ---- ca 6 med saltsyra. Till uppslamningen sattes 11 procent alun (raknat pa torrmassa), och pH installdes pa ca 4,5 med saltsyra, om detta pH joke erhallits genom tillsats av den vattenhaltiga sura saltlosningen. Sedan uppslamningen omrorts flera minuter, infordes en alikvot mangd polymer aldehyd-dispersion ekvivalent med 2,5 % av massans torrvikt och blandades omsorgsfullt med massauppslamningen vid pH = ca 4,5. Ark bildades sedan pa viran under anvandande av spadningsvatten vid pH = 4,5 och torkades (enligt TAPPI:s standardmetod T 402 m-49). Bleached sulphate pulp, which was ground to a 700 ml freeness according to SchopperRiegler, was used. 340 ml of a water slurry (300 parts per million total carbonate hardness) containing 1.2 g (dry basis) of the pulp was installed at pH ---- about 6 with hydrochloric acid. To the slurry was added 11 percent alum (shaved on dry mass), and the pH was adjusted to about 4.5 with hydrochloric acid, if this pH joke was obtained by adding the aqueous acidic saline solution. After stirring the slurry for several minutes, an aliquot of polymeric aldehyde dispersion equivalent to 2.5% of the dry weight of the pulp was introduced and mixed thoroughly with the pulp slurry at pH = about 4.5. Sheets were then formed on the wire using dilution water at pH = 4.5 and dried (according to TAPPI's standard method T 402 m-49).

Detta exempel visar nodvandigheten av att de polymera dialdehyderna ligga Mom ett lampligt molekylviktsomrade i vattendispersioner eller losning for erhallande av goda vat- och torrstyrkor hos pappersarket. This example demonstrates the necessity for the polymeric dialdehydes to be located in a suitable molecular weight range in aqueous dispersions or solution to obtain good water and dry strengths of the paper sheet.

Tabell 1. Table 1.

Disper- sionstidDial-Slitstyrka for dial-dehyd-kplem dehyd- Moleltylviagranser starkelse- starkelse-retention bisulfit% torr vat min 800 000-5 000 000 0,65 5,7 1, 500 000-4 000 000 0,63 6,6 1, 60 300 000-3 000 000 0,38 6,1 1,27 180 under 300 0000,19 5,55 0,71 kontroll4,9 0,14 Tabell 1 anger molekylviktsgranserna for Over 80 % av de polymera dialdehyderna i dispersioner erhallna genom hydrolysering av en 3-procentig suspension av dialdehydstarkelse i bisulfitlosning for olika tider vid 92° C, som ovan beskrivits. Mellon molekylsiktgranserna 300 000 till 000 000 erhallas exceptionella vatslitstyrkor. Papperets vatstyrka star i direkt samband med cellulosafibrernas dialdehydstarkelseretention, vilken i sin tur beror pa molkylviktsomradet for de polymera dialdehyderna i den anvanda vattenhaltiga dispersionen. Dispersion timeDial-Wear resistance of dial-dehyd-kplem dehyd- Moleltyl viagranser starch- strength retention bisulfite% dry vat min 800 000-5 000 000 0.65 5.7 1, 500 000-4 000 000 0.63 6.6 1.60 300 000-3 000 000 0.38 6.1 1.27 180 below 300 0000.19 5.55 0.71 control 4.9 0.14 Table 1 indicates the molecular weight limits for Over 80% of the polymeric dialdehydes in dispersions obtained by hydrolyzing a 3% suspension of dialdehyde starch in bisulfite solution for various times at 92 ° C, as described above. Between the molecular sieve limits of 300,000 to 000,000, exceptional water durability is obtained. The water strength of the paper is directly related to the dialdehyde starch retention of the cellulose fibers, which in turn depends on the molecular weight range of the polymeric dialdehydes in the aqueous dispersion used.

Tabell a Dialdehyd- slitstyrfa starkelse „ retention 4Pieln vat 000-000 0,02 0,29 60 > 20 000 0,02 0,14 90 > 20 000 0,02 0,14 Tabell 2 visor, att dialdehydstarkelse, som dispergerats i 1,8-procentig borax-losning (raknat pa dialdehydstarkelsens vikt) vid 92° C under olika, tidsperioder nedbrytes kraftigt till ett alltfor lagt molekylviktsomrade for de polymera dialdehyderna, for att god retention i cellulosafibrerna skall erhallas och for att de skola yam verksamma sasom vatstyrketillsatsmedel till cellulosafibern fore arkbildningen. Table a Dialdehyde wear strength reinforcement „retention 4Pieln vat 000-000 0.02 0.29 60> 20 000 0.02 0.14 90> 20 000 0.02 0.14 Table 2 shows that dialdehyde starch, which is dispersed in 1 8% borax solution (based on the weight of dialdehyde starch) at 92 ° C for various periods of time is greatly degraded to an excessively molecular weight range for the polymeric dialdehydes, in order to obtain good retention in the cellulosic fibers and to act as water strength additives. to the cellulose fiber before sheet formation.

Vid anvandning av dialdehyder, glyoxal och glutaraldehyd under samma anvandningsbetingelser som de nedbrutna dialdehydstarkelsedispersionerna erholls ingen vatstyrka lies popper. En vatstyrka av 0,14 kp/cm erholls med hada dessa amnen, vilket är detsamma som erholls vid det kontrollforsok, corn utfordes utan tillsatsamne. When using dialdehydes, glyoxal and glutaraldehyde under the same conditions of use as the degraded dialdehyde starch dispersions, no water strength lies popper. A water strength of 0.14 kp / cm was obtained with these substances, which is the same as obtained in the control experiment, corn is challenged without additive.

Exempel 2. En till 95 % perjodato3dderad starkelse behandlades i vatten for bildning av en dispersion, som till overvagande del inneholl polymera dialdehyder inom molekylviktsomradet 300 000-5 000 000. Delar av dispersionen sattes, som antytts i tabell 3, till 340 ml av en suspension av blekt kraftmassa i destillerat vatten, vilken malts till ca 700 ml draneringsformaga (SchopperRiegler), 300 delar per miljon natriumbikarbonat och darefter alun tillsattes i varierande mangder, och pH installdes pa 4,5 om sa befanns nOdvandigt, med saltsyra. Handdukar framstaildes i en laboratoriemaskin. Arken lades frau viran pa laskpapper och torkades enligt TAPPI:s standardmetod. De erhallna resultaten framga av tabell 3. Example 2. A 95% period-dated starch was treated in water to form a dispersion which predominantly contained polymeric dialdehydes in the molecular weight range of 300,000-5,000,000. Portions of the dispersion were added, as indicated in Table 3, to 340 ml of a suspension of bleached kraft pulp in distilled water, which was ground to about 700 ml of drainage form (SchopperRiegler), 300 parts per million sodium bicarbonate and then alum was added in varying amounts, and the pH was adjusted to 4.5 if necessary, with hydrochloric acid. Towels were made in a laboratory machine. The sheets were laid from the wire on tissue paper and dried according to TAPPI's standard method. The results obtained are shown in Table 3.

Tabell 3. Table 3.

Dialdehyd- starkelse tillsatt ' Ingen (kon- Alun Basis i ark tillsatt i arkvikt c°°/Xio/oo Slitstyrka hp/cm torrvat troll A) 11 47,4,81 0,16 Ingen (ken- troll B) - 0 -46,3 4,70 0,14 0,0,11 2,249,6 5,91,18 0,04 0 - - 4,60,16 1,0 0,11 2,250,2 6,36 1,57 2,0 0,67 11 2,850,6 6,1,83 2,0,61 11 2,247,8 6,57 1,92 0,59 5,2,348,8 6,37 1,12 0,2,2 1,847,3 6,17 0,77 0,34 0 - - 5,74 0, 5,0 0,83 11 1,949,6 6,63 1,89 0,84 5,1,248,3 6,72 1, 0,61 2,2 0,748,6 6,66 0,84 0,67 0 - - 5,77 0,77 Av tabell 3 framgar, att frail och med forsOket med 2,5 % tillsatt mangd okande mangder poly- Dialdehyd-starkelse-boraxdis-persion tid, min Moleltylvikt- granser - -- mera dialdehyder absorberas med okande mangder alun, och i allmanhet variera alltsa. vat- och torrstyrkorna hos papperet med mangden polymer dialdehyd i arket. Dialdehyde strength added 'None (kon- Alun Base in sheets added in sheet weight c °° / Xio / oo Wear resistance hp / cm dry water troll A) 11 47,4,81 0,16 None (control B) - 0 - 46.3 4.70 0.14 0.0.11 2,249.6 5.911.18 0.04 0 - - 4.60.16 1.0 0.11 2.250.2 6.36 1.57 2, 0 0.67 11 2,850.6 6,1,83 2,0,61 11 2,247,8 6,57 1,92 0,59 5,2,348,8 6,37 1,12 0,2,2 1,847.3 6.17 0.77 0.34 0 - - 5.74 0, 5.0 0.83 11 1.949.6 6.63 1.89 0.84 5.1,248.3 6.72 1, 0.61 2 0.7 2 48.6 6.66 0.84 0.67 0 - - 5.77 0.77 Table 3 shows that frail and with the experiment with 2.5% added amount of increasing amounts of poly- Dialdehyde-strength-borax-dis- persion time, my Moleltyl weight- limits - - more dialdehydes are absorbed with increasing amounts of alum, and generally vary thus. the water and dry strengths of the paper with the amount of polymeric dialdehyde in the sheet.

Vatstyrkan hos det papper, som bildats ur massa, som behandlats med endast 0,5 % dialdehydstarkelse i lamplig dispersion, var 790 % stone an for de icke behandlade proverna. Vid tillsatserna 2,5 och 5 % till massan och 11 % alun blev okningen ca 1300 °A. Det an hdr fragan om vatstyrkor (TAPPI) av 20 resp. 28 %, dar procenttalet vdtstyrka är fOrhallandet mellan slitstyrka i vatt tillstand och sadan i torrt tillstand for behandlat papper x 100. Ungefdr samma resultat erh011s med icke-blekt kraftmassa och med blekt sulfitmassa. The water strength of the pulp-formed paper treated with only 0.5% dialdehyde starch in suitable dispersion was 790% stone for the untreated samples. At the additions of 2.5 and 5% to the pulp and 11% alum, the increase was about 1300 ° A. The question of water strengths (TAPPI) of 20 resp. 28%, where the percentage of wettability is the ratio between abrasion resistance in the wet state and thus in the dry state for treated paper x 100. Approximately the same result is obtained with non-bleached kraft pulp and with bleached sulphite pulp.

Britt uppger i Paper Ind. 26, No. 1, sid. 37-41 (April, 1944) att papper, som visar en vatstyrka stone an 15 %, arises vara vatstarkt papper. Vid berdkning av den procentuella vatstyrkan hos papper, som enligt Meller behandlats med perjodatoxistarkelse, enligt TAPPI erholls de laga vdrdena av 9 % efter endast en minuts doppning och 6 % efter 60 minuters doppning, vilket betyder, att Mellers papper icke kan betecknas som vatstarkt papper. Britt states in Paper Ind. 26, no. 1, p. 37-41 (April, 1944) that paper, which shows a water strength stone of 15%, arises to be water-strong paper. When calculating the percentage water strength of paper, which according to Meller has been treated with periodate starch, according to TAPPI, the legal values of 9% are obtained after only one minute of dipping and 6% after 60 minutes of dipping, which means that Meller's paper cannot be described as water-resistant paper. .

Exempel 3. Forbdttrad sprangstyrka (burst strength) erhalles aven genom behandling av cellulosamassa med 95-procentig dialdehydstarkelse, som dispergerats enligt exempel 2, sasom visas i tabell 4. Example 3. Improved burst strength is also obtained by treating cellulose pulp with 95% dialdehyde starch, which is dispersed according to Example 2, as shown in Table 4.

Tabell 4. Table 4.

DialdehydstarkelseBasisSprangstyrka tills att %vikt%/45 kg (100 lbs) Ingen (kontoll)46,323,7 0,49,626,8 2,50,628,7 5,048,629,8 Exempel 4. Tabell 5 visar forandringen i vatslitstyrka med doppningstiden for papper, som behandlats sasom i exempel 1 under anvandande av 2,5 % dialdehydstarkelse i ldmplig dispersion. Dialdehyde starchBascent Bounce strength up to% weight% / 45 kg (100 lbs) None (control) 46,323.7 0,49,626,8 2,50,628,7 5,048,629,8 Example 4. Table 5 shows the change in water abrasion resistance with the dipping time of paper treated as in Example 1 using 2.5% dialdehyde starch in exemplary dispersion.

Tabell 5. Table 5.

Slitstyrka, kg/em TorrVatningstid, min 0,1 60 90 34,9 1,61,62 1,491,48 1,31,19 1,16 27,3* 0,0 * Icke behandlat papper. Abrasion resistance, kg / em DryWetting time, min 0.1 60 90 34.9 1.61.62 1.491.48 1.31.19 1.16 27.3 * 0.0 * Untreated paper.

Vatstyrkan minskade fran 26,6 % av den behandlade torrstyrkan efter 1/2 minut till 18,5 % efter 90 minuters behandling. Vid 90 minuter anses det emellertid annu vara vatstarkt papper. The water strength decreased from 26.6% of the treated dry strength after 1/2 minute to 18.5% after 90 minutes of treatment. At 90 minutes, however, it is still considered waterproof paper.

Exempel 5. En betydelsefull fordel dr, att dialdhydstarkelsebehandlat papper icke behover varmas under korta eller forlangda tidsperioder, for att en forbattring av vatstyrkan skall uppnas, sasom erfordras med melamin- och karbamidhartsbehandlade papper. Handdukar tillverkades av blekt kraftpapper, sa.som i exempel 1. Vaslitstyrkan for papper, som torkats vid rumstemtemperatur, var 4,2 kg/2,54 cm. Ungefdr samma vatstyrka erh'cills, efter det att arken torkat 5 minuter vid 100° C och vid 150° C. Example 5. A significant advantage is that dialdhyde starch-treated paper does not need to be heated for short or long periods of time in order to achieve an improvement in water strength, as required with melamine and urea resin treated papers. Towels were made of bleached kraft paper, as in Example 1. The vaslite strength of paper dried at room temperature was 4.2 kg / 2.54 cm. Approximately the same water strength is obtained after the sheets have dried for 5 minutes at 100 ° C and at 150 ° C.

Exempel 6. Majsstarkelse, som oxiderats med perjodsyra till en dialdehydhalt av 73 %, behandlades for erhallande av en vattenhaltig dispersion inom molekylviktsomradet 300 0005 000 000. En alikvot mane av dispersionen ekvivalent med 2,5 % tillsats av dialdehydstarkelse anvandes med blekt kraftmassa sasom i exempel 1. Handdukar framstalldes och torn- och vatstyrkorna uppmdttes.Torrslitstyrkan befanns vara 15,7 kg/2,54 cm, och vatslitstyrkan befanns vara 2,53 kg/2,54 cm efter 30 minuters behandling. Den procentuella vatslitstyrkan blir dad& 16 %, och arket kan betraktas som vatstarkt papper. Example 6. Maize starch, oxidized with periodic acid to a dialdehyde content of 73%, was treated to obtain an aqueous dispersion in the molecular weight range 300,0005,000,000. An aliquot of the dispersion equivalent to 2.5% addition of dialdehyde starch was used with bleached pulp sasom Example 1. Towels were prepared and the tower and water strengths were measured. The dry wear resistance was found to be 15.7 kg / 2.54 cm, and the water wear resistance was found to be 2.53 kg / 2.54 cm after 30 minutes of treatment. The percentage of cotton abrasion resistance is dad & 16%, and the sheet can be considered as waterproof paper.

Claims

Patent claim:

A method of producing water with water strength and substantially improved dry strength, characterized in that 0.3-1% by weight of water-dispersible polymeric dialdehydes obtained by partial decomposition of 70-100% of periodic oxidized starch is applied to the fibers of the paper. 80 oh, carried a molecular weight mom in the range of 300,000-5,000,000.

2. A kit according to claim 1, characterized in that the polymeric dialdehydes are added to an aqueous suspension of cellulosic paper starting material and water, and that the treated material, after absorbing the polymeric dialdehydes, is transferred to an aqueous sheet and. torkas. Request publications: Stockholm 190

3. Kungl. Boktr, P. A. Norstedt Saner. 636089