GB2211519A

GB2211519A - Rot resistant paper

Info

Publication number: GB2211519A
Application number: GB8825307A
Authority: GB
Inventors: Jukka Erkkila; Matti Niskala
Original assignee: Lannen Tehtaat Oy
Current assignee: Lannen Tehtaat Oy
Priority date: 1987-10-29
Filing date: 1988-10-28
Publication date: 1989-07-05
Also published as: SE8803758L; SE8803758D0; FI80741B; DE3836658A1; FR2622608A1; FI80741C; FI874769A0; ES2009085A6; FI874769A; JP2739132B2; CA1339948C; DE3836658C2; JPH026692A; GB8825307D0

Description

Modified paper 2211519 The invention concerns a paper in whose cellulose

part of the hydrogen groups in the hydroxyl groups have been substituted with N-methylol compounds. The paper is suitable for use in particular in applications in which good resistance to rot is required.

From the published Patent Application WO 84/04553, LRnnen Tehtaat Oy, it is known to improve the rot resistance in particular of conifer cellulose by substituting the cellulose with certain N-methylol compounds, in particular with dimethyloldihydroxyethyleneurea, or with monomethyloldihydroxyethyleneurea. The papar obtained in this way also has good wet strength. one of its drawback is, however, brittleness.

is Now it has been found that the brittleness can be reduced by using certain N-methylol compounds and between the fibres attaching a suitable, for example hydroxyfunctional polymer. A particularly suitable polymer is polyethylene glycol (PEG).

A polyethylene glycol molecule used may contain, e.g., 2 200 monomer units, preferably 10-40 units.

The N-methylol compounds are selected from the group consisting of methyloldihydroxyethyleneureas and methylolacetylenediureas. Above all dimethyloldihydroxyethyleneurea (DMDHEU) can be concerned, but, for example, also tetramethylolacetylenediurea (TMADU) is suitable.

The paper is manufactured appropriately, for example, of pine sulphate cellulose.

The paper can be manufactured by impregnating paper with a solution that contains the N-methylol compound and the polymer and by thereinafter drying the paper at a raised temperature, whereby the reaction takes place between the N-methylol compound and the cellulose. For promoting the reaction, suitable catalysts are used.

According to an embodiment, glyoxal is used with poly- ethylene glycol, appropriately 2 moles per one mole of PEG, or more. Glyoxal can react with the end groups in PEG. The mode of reaction of N- methylol compound, glyoxal and PEG with cellulose has, however, not yet been established.

2 In the following, the invention will be described in more detail with the aid of examples.

Paper was impregnated with solutions that contained N-methylol compound, PEG and a catalyst, and the paper was dried at a raised temperature. The properties of the papers obtained were tested before and after a so-called fungus burial treatment.

The fungus burial treatment was as follows:

The necessary equipment and materials were sterilized in an autoclave at a pressure of 1 bar and at a temperature of 120 0 C for 50 minutes. A pure culture of mycelium. (Aspergillus niger + Cladosporium resinae) was inoculated by means of a flamed platium wire into distilled water placed in a decanter glass. Pearls of glass were added with subsequent agitation so as to disperse the mycelium into the water as well as possible. Sample pieces were submerged into the fungus water for 4 hours, whereupon they were transferred into sterilized culture peat provided with basic fertilizer and placed in foil vessels. Protected with a plastic foil, the vessels were transferred into an incubator cabin to be kept there at a temperature of 28 0 C and a relative humidity of 100 % over the desired period.of time.

Example 1

A MDHEU basic solution was prepared, which contained DMMEU solution, concentration 45 % 40 g MgCl 2 - 6H 2 0 4 g Water 1 1 as well as a PEG basic solution, which contained PEG (n = 2... 181) solution, concentration 45 % 18 1350 g Glyoxal solution, concentration 50 24 g Al 2 (SO 4)3 16H 2 0 2 g Tartaric acid 1 g Water 1 1 3 MgC12 catalyzes the reaction of MHEU, and Al 2 (SO 4)3 the reaction of glyoxal. The quantity of PEG depended on its average monomer number n. By means of tartaric acid, the impregnation solution was made acidic. 5 Said basic solutions were mixed at a volumetric ratio of 4:1. Kraft paper (UG 70 g/m2) was impregnated with the solutions obtained in this way (pick-up 100. %), and dried for 10 minutes at 160 0 C.

The determinations made from the papers were increase in weight on impregnation, dry and wet tensile strength before the fungus burial rot treatment described above, and wet tensile strength after the rot treatment.

Test results are given in the accompanying table.

n PEG Weight Tensile strength N/60 mm increase bef. rot treatm. after rot treatm., -,p-t 1 % dry wet 3 days 15 days J7 days 114 dayl un 3 1 treated 1 - 460 40 4 1 - 1 -1 - 1 1 2 1 1,95 420 268 180 172 145 31 9 2.31 360 260 167 153 141 35 22 2.97 400 240 149 122 74 31 2.50 380 244 158 51 '31 14 181 2.71 348 248 157 102 54 8 From the table it can be seen that the resistance to decay has become lower when PEG of a higher molecular weight has been used. Example 2 Solutions prepared in accordance with Example 1 wherein the monomer number n of PEG was 22, were mixed at different proportions. The impregnation and the tests were carried out as described in Example 1. Test results are given in the accompanying table.

( 4 DMDHEU Wbight Tensile strength N/60 mm solution: increase bef. rot treatm. lafter rot treatm.,.et PEG solution % (nPEG = 22) dry wet 3 days 15 clays 7 days 4 day 1 7IS 5:0 1,94 420 268 162 146 142 66 4:1 2,97 400 240 149 122 74 31 3:2 3.98 420 240 131 74 37 2:3 4.97 404 196 117 38 8 1:4 5.95 368 140 46 11 10 0:4 6.90 328 112 45 10 From the table it is seen that the resistance to decay became lower when the proportion of PEG in the solution was increased. The proportion of the PEG solution is optimally about 10... 30 Example 3

Solutions were prepared in the way described in Example 1, except that in the DMMEU solution the catalyst was Zn(NO 3)2 4H20 as a quantity of 4 g per litre. The impregnation was carried out as in Example 1, but the drying conditions were varied. Test results are given in the accompanying table.

-Heating Tensile strength N/60 mm tine te- bef. rot treatm. after rot treatm., %et min. ature OC dry wet 3 days 15 days 17 a Is_ 114 clayEl 1 2 1 150 420 j 244 122 53 44 31 4 150 410 266 > 200 > 200 > 200 - 132 165 363 265 > 200 > 200 > 200 >200 By using a Zn-catalyst, a better rot resistance was obtained than by using a Mg-catalyst.

Example 4

Solutions were prepared and impregnations were carried out as described in Example 3, except that in stead of MHEU, TMADU was used. Test results are given in the accompanying table.

n PEG Weight Tensile strength N/60 mm increage bef. rat treatm. 1 after rot treatm., p-t % dry t f-3'5;y_s 5.M 17_ clays 114 2 150 464 189 39 32 30 26 4 150. 452 169 101 82 80 64 16.5 404 260 > 200 > 200 > 200 >200 j is. Thus, with TMADU, an equally good resistance to rot was not obtained as with DMDHEU. Example 5 Impregnations were carried out in accordance with Example 2 with solutions of different proportions, wherein the monomer number of PEG was 45. The fold number of the papers was determined. Results are given in the accompanying table.

DMIM solution Fold number -PEG solution rachine direct. transverse directim untreated 1105 675 5: 0 70 66 4:1 220 161 3:2 415 183 2:3 440 286 1:4 1185 462 0:5 1350 530 It can be ascertained that an increased amount of PEG increased the number of double folds.

6 Example 6

Impregnation was carried out in accordance with Example 2 with solutions of different proportions, wherein the monomer number of PEG was 22. The dry and 5 wet tear resistances of the papers were determined. Results are given in the accompanying table.

DMDHEU solution Tear resistance reN PEG solution dry wet untreated 255 140 5:0 150 230 4:1 220 265 3:2 230 295 2:3 240 335 1:4 240 340 0:5 200 180 It can be ascertained that the modification reduced the dry tear resistance but increased the wet tear resistance.

7

Claims

WHAT IS CLAIMED IS:

1. Modified paper that contains cellulose, wherein part of the hydrogen groups in the cellulose have been substituted with a N-methylol compound, c h a r a c t e r i z e d in that the N-methylol compound is selected from the group consisting of methyloldihydroxyethyleneureas and methylolacetylenediureas, and that the paper additionally contains organic polymer.

2. Paper as claimed in claim 1, c h a r a c t e r - i z e d in that the polymer is hydroxyfunctional.

3. Paper as claimed in claim 2, c h a r a c t e r i z e d in that the polymer is polyethylene glycol.

4. Paper as claimed in any of the preceding claims, c h a r a c t e r i z e d in that the amount of the N- methylol compound is 0.5... 10 % of the weight of the paper.

5. Paper as claimed in any of the preceding claims, c h a r a c t e r i z e d in that the amount of the organic polymer is 0.5... 10 % of the weight of the paper.

6. Paper as claimed in any of the preceding claims, c h a r a c t e r i z e d in that the paper additionally contains glyoxal.

7. Paper as claimed in any of the preceding claims, c h a r a c t e r i z e d in that the N-methylol compound is dimethyloldihydroxyethyleneurea or tetramethylol- acetylenediurea.

8. Paper as claimed in any of the preceding claims and containing conifer cellulose. 1

9. Method for the preparation of modified paper that contains cellulose, in which said method part of the hydrogen groups in the cellulose are substituted with a N- methylol compound, c h a r a c t e r i z e d in that the N-methylol compound is selected from the group consisting of methyloldihydroxyethyleneureas and methylolacetylenedi ureas, and that organic polymer is added to the paper.

10. Plant-growing cell system which is made of modified paper that contains cellulose, part of the hydrogen groups in said cellulose being substituted with a N-methylol compound, c h a r a c t e r i z e d in that the N-methylol 8 compound is selected from the group consisting of methyloldihydroxyethyleneureas and methylolacetylenediureas, and that the paper additionally contains organic polymer.

11. Modified paper substantially as hereinbefore described with reference to the accompanying drawings.

12. Method for the preparation of modified paper substantially as hereinbefore described with reference to the accompanying drawings.

13. Plant growing cell system substantially as hereinbefore described with reference to the accompanying drawings.

Published 1989 atThe Patent OfEice, State House, 66.71 High Holborn, UndonWC1R 4TP. Further copies maybe obtained from The Patentoffice.

Wee Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary er&v. Kent. Con. 1187 Wee Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex techniQues ltd. St Marv crav. x,.nt. rn, 1 IR7