DE2113216A1 - Lightweight paper of high stiffness - Google Patents

Description

Applicant: -! Feldmühle. Corporation,

4 Düsseldorf-Oberkassel, Eritz-Vomfelde-Platz 4

Annex to the entry from March 16, 1971
Pat / 12o95 / Ha / Hx.

Lightweight paper with high stiffness.

The invention "relates to a lightweight paper high stiffness for use in office and duplicating machines.

Office technology has undergone a revolutionary development in the last ten years, in particular regarding copying procedures and documentation and electronic data processing at ever increasing speeds has led. So is everyone from everyday life known the xerοgrafische procedure, which up to then usual conventional copying processes based on photographic Processes were based, completely replaced.

The ever higher working speeds of the devices used for this, such as copiers and document readers, place considerable demands on the properties of the papers used in these devices. It has been particularly disadvantageous to this day that the papers used for this purpose must have a relatively high weight. A perfect through-1 & ΙΙ.Ϊ c'JurcJ: the device is only guaranteed if these papers have sufficient rigidity. On the other hand, "/ isr-eri these breadings are easy to fold and also have a certain latitude and sufficient opacity. From these 'lr ^: ' n ^r tea v / ar so far an induction of the iflien weight. '• olc'tor' breading not possible and. the surface weight that

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the manufacturer also prescribes that the size

Order "at 9o g / m.

This has the considerable disadvantage that such Copies in their strength and weight, often-increasing * - lie above that of the original. With the flood of paper, which is increasing inexorably, and the problems associated with it the office space, the required storage space and the Postage costs there is an urgent need for a lightweight, high rigidity paper that defies satisfies all requirements and guarantees a smooth run through the devices available on the market. The usual ones at the disposal of the papermaker fail standing specialist treatment options, such as impregnating or painting the paper completely. An impregnation of the memo paper results in a 'continuous rigidity, * so that the required foldability and elasticity of the paper are not

more is given. Deletion procedures that fix this ITacli part could because sit. Represent surface refinements, therefore do not bring the desired effect, because a weight Savings in the Sohpapior through the G-ewiclit of the line is canceled again.

According to the present invention, this urgent problem is made available by a lightweight paper of high rigidity in office and multiplication units solved by that there are tough-elastic outer layers on both sides and a voluminous one Has inner layer.

Such a paper is given by the zälielastisehen. Layers of the absolutely necessary rigidity line iot because of its voluminous interior, nevertheless "ut foldable, still sufficiently elastic and of sufficient Op: .zit" .t. l>n;-c> this construction principle is possible-licl, dar- das Crsviclr '; of oak paper for office and duplicating devices aiii. · ¹ '". Range of 35 - 7 °;' J can be lowered. Since the surface weight best suited for ^{1 pm depends on the respective}

2 ° ^9841/0241 BADORH ₃₁ NAt

The intended use and depending on the device, but is in any JJ ¹ AIl considerably below the previous weight of customary for papers. The property of tough elasticity in the outer layers is necessary because, despite the required rigidity of the paper, the palz number usual for office papers must be guaranteed and the outer layers must not break open even with repeated folding.

The technical problem on which the invention is based is solved particularly advantageously by a lightweight paper, its viscoplastic outer layers of the reaction product made of high polymers containing hydroxyl and / or amino groups and on these interlinking and acting compounds are formed. Here are of the high polymers in particular those with a molecular weight of over 2,000 are suitable, preferably from 5,000 to 30,000. The cheapest molecular weight eich is somewhat dependent on the weight per unit area of the Base paper. The lower the basis weight, the higher should be the molecular weight of the high polymer to prevent too deep penetration or even impregnation. Therefore, in a preferred embodiment of the invention, the viscoplastic outer layer additionally contains Thickeners, such as bentonites, which are not included in the crosslinking reaction, but are make it possible to optimally control the viscosity and prevent penetration of the base paper. A thorough impregnation is advantageously additionally made more difficult by the fact that the base paper is glued and thereby the building board principle strict is preserved.

As high polymers containing hydroxyl and / or amino groups In particular, polyvinyl alcohols are recommended all of the highly hydrolyzed types, starches and starch derivatives ; fie loxylated starch and oxyalkyl esters of acrylic and lietr.acrylsüure and ani & e -these acids, whereby the

209841 / 02A1

8AD ORIGINAL

synthetic high polymers also copolymers with other olefinically unsaturated "compounds such as iithyleri, Know propylene vinyl acetate and vinyl chloride represent.

The high polymers expediently also contain an addition of Io up to 60 percent by weight of protein compounds such as casein and soy protein - based on the weight of the high polymers ... These components bring a further gain in stiffness. However, the proportion of protein compounds should be more than 60% by weight do not go, because otherwise the outer layers will become too brittle and there will be insufficient toughness and thus the number of folds more is guaranteed.

Substances with a crosslinking effect are those containing hydroxyl and / or amino ß; rupp en in their crosslinking effect Highly polymeric known aldehydes, aldehyde-releasing substances or precondensates built up with aldehydes such as Formaldehyde and acetaldehyde, glyoxal and hexamethylenetetramine melamine-formaldehyde, urea-formaldehyde Application.

Those lightweight papers in which the crosslinking reaction to the Hocl'polpolymer in there is an interaction of these aldehyde compounds with gyanamide. The hit use of cyanamide brings the very considerable advantage that cyanamide takes on an additional function and a bridge bond between the base paper and the outer layer. This additional solidification of the outer layer and simultaneous Anchoring with the BasisOapier has iiisbesonde.re for duplicating papers a very significant meaning, which will be discussed further below.

The crosslinking action is expedient by adding from. Accelerated catalysts, such as NaO], ΐνίϊΐλ01 UOl or Lewi acids.

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Vie; It has already been stated that in the production of the original light, weight 13; en paper, it is important that components for the elastic outer layers do not chirchimpregnate us. To prevent this, the use of high-molecular-weight polymers has already been mentioned , the additional use of thickeners and the use of a sized base paper. On the other hand, it is of course necessary that. For this reason, the components for the viscoplastic outer layers, ie in particular the hydroxyl-containing high polymers and the crosslinking substances, are expediently combined during manufacture immediately before application to the paper This prevents the crosslinking reaction from starting and the rheological properties of the mixture from changing unfavorably. Another advantageous variant of the method consists in placing the components one after the other on the Papda? to apply, ie first the high polymers and then the crosslinking substances. This has the advantage that the two components only come together on paper and so there is no risk of c: .3 due to machine downtime, carelessness, etc. occasionally boioo components interact for a long time before the application and solidify through networking, the corresponding • 'ief.'Vilc and application aggregates clog and each time laborious. ■ .arider must be cleaned.

You is iürfindung in previous versions of the beneficial ''i.'ift'iu -oeir.oiel of outer layers of preferred hydro- vy \ --uoDorüialtigen high polymers. ^1! And then crosslinking ./i."':ori- Icn .V'ib.'rüonscn has been described. This preferred aur-i ' ^: ' hruii ^r - £ -: -. Vo-i.'i; i kon-.it therefore so important because

-G-

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especially for papers for duplication processes, especially xerographic processes in addition to the requirement the light weight, stiffness and still good durability such a paper still has a whole lot should have further properties as guaranteed by the preferred embodiment.

So it is required of these papers that their writability and printability is maintained and they are sufficiently opaque,

that they have the highest possible surface conductivity

^ so that there is no electrostatic charge when passing through through the devices such as copiers and document readers occurs, which causes the leaves to stick together, that the tough-elastic outer layers are not film-forming are, but 'their air permeability is maintained, so that they are held in the devices with suction air can that they are heat-resistant and do not yellow when exposed to heat, that the. Outer layers not abrasive and are therefore not at risk of dust and dirt it is given that the stiffness and compressive strength are not is lost in the warmth, with which for all; the application purposes, where the action of heat takes place, thermoplastic outer layers are unusable,

P that the outer layers as possible from the aqueous phase can be made out.

Outer layers made of hydroxyl- and / or amino group-containing high polymers and thereon crosslinking substances are particularly good. The invention but is not limited to this particularly preferred embodiment, but rather has the superordinate inventive concept to the object that consists in the fact that through the ver. proportionately voluminous inner layer in connection with tough elastic outer layers the required rigidity and compressive strength with low flatness: -: ev; Ib achieved-

■ 20 984 1/02 41 _{BAD 0R1G1NAL}

is and uas paper is easy to fold and sufficient Opacity "possesses.

The foldability and the other mechanical properties, to whom "increased importance for lightweight papers-" Ίοϊπΐηΐ, are therefore further improved in that a base paper for the production of the paper according to the invention It is used that, in an alkaline medium, it is expediently produced in a pH range from 7 »2 to 9 * 7. Such a base paper has a better paser to fiber bond, the for the purposes of this lightweight Papers is of particular importance.

the following is the production of a lightweight High rigidity paper described using an example:

Example 1:

Go ^c / o sulphate needle pulp and 40% sulphate leaf pulp are brought to a freeness of 38 ° SR in the usual way and mixed with 6 ^c / o calcium carbonate as filler. At a pH of 7-8 to 8, a paper sheet is then formed on the paper machine, which in the manner customary in paper manufacture by metering in a ketone dimer (product 4q.uapel from Hercules Powder Comp) and fixing with a cationic Polyamide resin (product Cyrnono ' ^: yjl from Hercules Powder Comp.) Is glued. Kit of a zlakclotreicheinrichtung the paper is propariort on both sides with a spread τοπ 1.5 to 1.7 g / ^{m <} ~ (anhydrous) per side. The preparation solution to be used for this spread is prepared in the following way:

To an aqueous solution of 12o ;; / Ltr. Höchstpolyneri- ^ j.orten medium and high / viscous vinyl alcohol with a V - :: r;.: eifT; n ^; ; r;: ". ac". from 99 _? 9 / ο becomes the same amount of a w'Assricen Losun-; von 12o , J'LtT, i.olariinformaldehyde - Pre

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condensate added. Mixing the "two mentioned." Solutions may only be made and taken shortly before use For this reason, the two solutions are transferred to the coating pan and overflow via a small mixing vessel with a feed pump constant and evenly dosed into this mixing vessel.

It is then expediently at a temperature of over 100 125 ° G or above, the crosslinking reaction is carried out in the dryer section of the paper machine.

Example 2:
fc 20% of a fine wood pulp with a grinding degree of:

expediently 75-82 ° SR, bleached, are ground with 4-0% long-fiber sulphate pulp, 25 % leaf pulp and 15% de-stippled waste paper are mixed to form a whole material with a freeness between 35 and 4-0 ° GR. The paper is fully sized in the usual way with resin glue and alum and pulled out at a pH value of 4-5 to 4-8. A mixture of 50 parts of bone gelatin, 5 parts of high-polymer, highly hydrolyzed polyvinyl alcohol, 25 parts of urea-formaldehyde precondensate and 0.5 parts of sodium bentonite is coated on a knife coater. As above, the aldehyde precondensate is only metered in immediately before application.

The solids content of the coating slip depends on the necessary viscosity under the squeegee and according to the desired

p th order. Here, too, an application of 1.5 to 5 t / m is sufficient " .the side.

Example 3

Made of 4-0 % long fiber sulphate pulp
5o% sulphate birch pulp and

Io ° / o wood-free paper is in the usual Ueioe with the addition of

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Io, j Ciiinr.-Glay aiii sheet of paper formed. The pH Verc; cheats 7j - '·· you will be gluing with ketendimer (Aquapel) and oin ^ m nitrogen-containing 2 retention agent, (Luresin K 2o the Badische Anilin- & Soda Fabriken). On a Size press will have a surface preparation measure as follows Composition applied:

δ yö ii highly hydrolyzed polwinyl alcohol (e.g. Mowiol
? '5/99 from Farbwerke Hoechst AG)

G Jj Melamine formaldehyde precondensate (e.g. Madurit OP) and 2 % monomeric oyanamide.

Here, the components are only mixed immediately before being applied to the paper web. In the drying process following the size press, the paper web becomes as high as
possibly heated and expediently wound hot while avoiding cooling.

Bcirroiel 4:

corresponds to example o. In this case, half of the Vi: n.ylalkoLols replaced by bone gelatine '"2.t.

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Claims (1)

Applicant: LFeldmühle Aktiengesellschaft, ^L \ - Düsseldorf-Oberkassel, iritz-Vocaf elde-Platz ^z l- Pat / I2o95 / Ea / Hx. Claims. Lightweight paper of high rigidity for use in office and reproduction machines Because of the tough elastic outer layers on both sides and one voluminous inner layer. ™ 2. Lightweight 1 aper according to claim 1, characterized reVonnzeichnet that the viscoplastic -Auß ens chi CHT h of de "u TJmsetzungsprodukt of: - ^{r ':;} ro: -.. ^:;; l- uni / or high polymers and aminogruopeiilialtigen ". on these cross-linking compounds is formed. 'j>. Lightweight paper according to one of the claims 1 and 2, characterized in that the Irrdroir, / -! Uni / or s.minogruppenlialtigen Hochpolyueren Io relative to 6o weight ca "protein compounds ent tiHit ^ F ¹ on the weight of the high polymers. h ^z l ·. Lightweight paper according to one of Claims 1 to> ·, characterized in that the hydrocyclic and / or amino group-containing hoclipolycaers have a molecular weight of more than 2,000, preferably 5,000,000. 5 ' easy-slip paper according to one of claims 1 to'! -, characterized in that the zühelcstisclie Ai.ü'.c: a.schicht a.us the Gemieclj. from hTclrosqyi- and / or aminorrupO-oriiialti; c - n Ilochpolymeren and crosslinking oubstnizen svc: · Control of viscosity and prevention · \ α · x'cnel ·. ·· "." !: ic.λ do not react · ""'e Vrrdic "un;: ciiiti;:; l --urweipt. 209841/0241 _BAD ■ ':,. Leiciitgewicliti -.- is tapir according to any one of claims 1 to ¹ , characterized in that the crosslinking substances are aldehydes, aldehyde-cleaving substances or aldehyde-based constituents. 7- lightweight paper according to claim - ^; 4-, characterized in that the crosslinking substances additionally contain 3o to 1fjo percent by weight of cyanamide. '".;. Method of making a lightweight paper according to one of claims 1 to 7? characterized, da3 the components for the zühelastinchen outer layers brought together on the paper immediately before the application. '). Process for the production of a lightweight paper according to one of claims 1 to 8, characterized in that the components for the viscoplastic outer layers are used be applied one after the other on aas paper. 10. Procedure for:? Production of a lightweight paper according to one of claims 1 to 9, characterized in that the crosslinking reaction is effected by adding catalysts is accelerated. 11. A method for producing a light weight paper according to any one of claims 1 to 10, characterized in that: ¹ as base paper, a paper produced in an alkaline kilieu with a value of 7 »2 to 9.7 is used as the base paper" Luc et. 12. Process for the production of a lightweight paper according to eiiiea of claims 1 to 11, characterized in that öa; 3 al α base paper a sized paper is used. 2 09 8 Λ 1/0241 BATH ORIGINAL