DEP0053512DA - Process for the production of nonwovens, in particular cardboard - Google Patents

Description

Dr. Michael Erlenbach

Dr. Adolf Sieglitz

by address:

FARBWERKE HOECHST Frankfurt am Main-Höchst

Appendix II

^ 10, Mei 1950 Dr, Bg / Ro

to the patent application Fw.

198

Process for the production of nonwovens, in particular Pcppen »

It is known to strengthen nonwovens plus cellulose fibers, wood pulp and similar cellulose-containing materials Fiber sterile a glue e from animal or vegetable source material to use “Also are fine Plastics of various kinds have been used for this purpose - the application knows before, during or after the actual formation of the fleece take place, whereby the plastic is processed together with the Fcsera or the finished fleece is subsequently incorporated. It is also known to apply heat to the finished nonwovens and low pressure (drying cylinder) or heat and higher pressure - rather only acting for a short time - (hot celander) to solidify "

In particular, in the production of paperboard and Pepier, it is already known that an IIaturleim or a synthetic resin in solid form or in the form of a solution or dispersion is added to the pulp in the Hollander and this substance is optionally added by adding an electrolyte, Z _c B ₀ alum, euf die Fibers are felled »The refinement of such peppers by brief heating while simultaneously applying pressure (e on the hot calendar), especially for smoothing

Fw _c 198

the surface “is also already known. For this purpose, the cardboard runs about 2-5 Mel between the hot Calendar rollers through.

We have found _s that the finishing of such with the addition of polymer emulsions in the Dutch produced nonwovens, especially Pappeii much _j continue to be driven when additionally calendered finished nonwovens according to the usual smoothing in the warmth and bezWc or pressed "With A smaller number of passes through the calender is sufficient for thinner nonwovens, a larger number is required for thicker fabrics in order to achieve the optimum effect. Too large a number of passages is uneconomical and can damage the fibers «

As a rule, at least about 10 runs are required. Particularly favorable results are achieved with about 20 - 30 passes achieved, while it is generally not necessary or even not expedient, the number of 35 passes to be exceeded “Instead of calendering, thorough pressing at a higher temperature can also be used step “The number of ISLander passes or the time of pressing can be reduced by the fact that one the fleece is warmed up for some time beforehand.

The effect achieved is that, by the simultaneous action of heat and pressure are pressed together the fibers and the plastic pieces located on them are melted, whereby they fill the spaces between the individual fiber particles and the fibers with each other welding _u This welding also holds for the ArbeitsgEJig the Fibers together "The result is a much denser, stiffer and stronger material that is more resistant to the penetration of water than normal cardboard, even if an inherently hydrophobic plastic has not been used." one almost of a new kind of work

Fw. 198

Speaking of substance »For example, by adding 5 ° polyvinyl acetate in dispersion form in the Hollander to a raw material for ordinary gray cardboard and mandreling the cardboard made from it 20 times, a material is obtained which in various respects is made from a specially selected raw material - but without the treatment according to the invention - manufactured cardboard still exceeds =

If hard cardboard is produced in an analogous manner from specially selected cellulose material, its properties are far better than those of conventional hard cardboard. The boards thus produced can be used as Hertplatten for luggage manufacturing as cardboard folder, for the production of Radiο rear walls and of joints and caps for shoes and erwendet for other purposes \ ^T. The P & ppen have excellent stability and flexural strength and show a smooth, shiny surface in addition to significantly increased tear resistance, especially after immersion in watero In the attached table, the dry and wet strengths obtained according to the above process are compared to those obtained with the same cardboard according to normal Calendering have been obtained.

j dry J water resistance kg / cm

Cardboard type j treatment I strength! -—. "■

I kg / cm ^c I 10 see! 10 minf 2 h124h

Gray cardboard weight I normal I, I i

1, 6 mm I calendered 276 I \ J 231 30.9 '17.6 1% 3

5io polyvinyl | ■■ j - -f— - ■■ - ■ f - ■ ■; - ~~~ -

acetate im ) sus &zlich>] ¹ ] I

Dutch] 30 times ka-, 398 '326 i 56.5, 23.4

added landed » \ '· χ

Hard cardboard! Normal * | ^4th

1 , 6 ma Icalendered ■ <222 f 218 152 ''18, 2 15 /

5 <? O polyvinyl | _ _4__ | j .— ~ _r ——

acetate in addition; I ', \

Dutchman | 30 times ka- "332 I 316 \ 252 33.8 25.8

suspended ILanded ¹ f!

Gew ₀ gray cardboard | iorm.kafendr. ■> J>

5fo polyvinyl- f130 ° 5 min. 374 ■ 382 '306' - 65.7 ^! 42.8

acetate in the f 80 kg 'ι. ;

Dutch I:?

added fj *

Fw ₀ 198

From the table it can be seen that meliges 30-by susätzliches Ki-Icndriereri heightening an essential Pestigkeiteer both the G -raupappe;. Ls cloth of Iifirtpappe has been ersielt _c addition but you is to significantly improve their other properties remarkably zv ι After being calendered 30 times, both types of ptp have a much better appearance, especially a smooth, glossy, smudge-proof and abrasion-proof surface; they have a much greater hardness, density and pull-out strength ice before Kalcndrieren, you have a greatly increased standing and bending strength and give a good _t hard when struck sounded "

The effect found cannot be foreseen without further ado, because peppers, like most nonwovens _li poor heat conductors, are _jl the warming from the outside is only slow and difficult to take effect on the inside ο /

The refinement of cardboard treated with polyvinyl acetate dispersions is described in the examples "The procedure can, however, be used with any type of gluing, for example when using Dispersions of polyacrylic ester !! or melamine resins «

Eeispielli

An amount of prepared fiber material for Gre.upappe corresponding to about 150 kg dry substance is put into the Dutchman with the required amount of water and this is put into operation. Then the necessary amount of polyvinyl acetate dispersion of about 50 solid amounts is added afterwards, for example about 15 kg. Towards the end of Holländerns (about 20 1 10 ^ aqueous solution) of the plastic precipitated with A-Iuminiumsulfat to the fiber, after having Ammoniek euf the pH of about 7.0 has been set ₀ The thus-treated mass is in let the vat run, and then turned it into cardboard on the cardboard machine;

Fw «198

the latter are dried, calendered two to three times as usual and then either immediately or at a later date Time sent 20 - 30 times through the calender heated to approx. 100 ° = after cooling, the resulting Spice up immediately ready to use "

Example 2;

An amount of prepared Ptsermaterial for hard cardboard corresponding to approx. 150 kg dry fiber filled with the necessary amount of water in the Dutchman and put it into operation. This is done during the cooling the desired amount, for example 7.5 kg of a 50% polyvinyl acetate dispersion admitted. With about 10 liters of a 10% aluminum sulfate solution, the precipitate is deposited on the fiber brought about and then the mass, as stated above, processed into cardboard »These are after drying briefly calendered and then immediately or on occasion another 20-30 mel through the calender. the The particularly beautiful hard cardboard obtained in this way can then be further processed immediately,

Claims (2)

Patent claims s 1) Process for the production of nonwovens, in particular cardboard, from dispersions of cellulose fibers with the addition of plastic dispersions and precipitation of the plastics in the Dutch, characterized in, that the finished nonwovens, after the usual smoothing, are additionally calendered and heated or pressed will, 2) Method according to claim 1, characterized in that the nonwovens prior to calendering or pressing be heated.