FI80741C - PAPER MODIFICATION. - Google Patents

Description

1 80741

Modified paper

The invention relates to a paper in which some of the hydrogen groups of the hydroxyl groups of cellulose have been substituted by N-methylol compounds. The paper is particularly suitable for use in areas where good rot resistance is required.

Patent application from WO 84/04553, Lännen Tehtaat Oy, is known to improve the rot resistance of softwood cellulose in particular by substituting cellulose with an N-methylol compound, especially dimethylol dihydroxyethylene urea. The paper thus obtained also has good wet strength. However, its weakness is fragility.

It has now been found that brittleness can be alleviated by attaching a suitable polymer, for example hydroxy-15, between the fibers. A particularly suitable polymer is polyethylene glycol.

The polyethylene glycol molecule (PEG) may contain, for example, 2 to 200 monomer units, preferably 10 to 40 units.

N-methylol compounds are, above all, di-20-methyldihydroxyethylene urea (DMDHEU), but also, for example, tetramethylol acetylene diurea (TMADU).

The paper is suitably made of, for example, pine sulphate distillate.

The paper can be prepared by impregnating the paper with a solution containing the N-methyl-25 compound and the polymer and then drying at an elevated temperature, whereby the reaction between the N-methylol compound and the cellulose takes place. Suitable catalysts are used to promote the reaction.

In one embodiment, glyoxal, suitably 2 moles per mole of PEG or more, is used with polyethylene glycol. Glyoxal is able to react with PEG terminal groups. However, the reaction of the N-methylol compound, glyoxal and PEG with cellulose has not yet been elucidated.

35 The invention will now be described in more detail by way of examples.

The paper was impregnated with solutions containing N-methylol compound, PEG and catalyst and dried at elevated temperature. The properties of the obtained papers were tested before and after the so-called fungus Burial treatment.

The Fungus Burial treatment was as follows:

The necessary equipment and materials were sterilized in an autoclave at 5 bar and 120 ° C for 50 minutes. Purely cultured fungal mycelium (Aspergillus niger + Claodporium resinae) was transferred with flame platinum wire to distilled water in a beaker. Ia beads were added and mixed to cause the fungal mycelium to disperse as well as possible in water. The specimens were immersed in fungal water for 4 hours, after which they were transferred to sterilized basic fertilized growth peat in foil containers. The vessels were transferred to a temperature cabinet, protected by plastic wrap, at a temperature of 28 ° C and 100% relative humidity for the desired time.

Example 1

A DMDHEtJ stock solution containing DMDHEU solution was prepared at a concentration of 45% 40 g

MgCl2 * 6H2O 4 g 20 Water 1 1 and PEG stock solution with PEG (n = 2 ... 181) solution, content 45% 18 ... 1350 g

Glyoxal solution, content 50% 24 g A12 (SO4) 3 · I6H2O 2 g 25 Tartaric acid 1 g

Water 1 1

MgCl 2 catalyzes the reaction of DMDHEU and the reaction of Al 2 (SO 4) 3 glyoxal. The amount of PEG depended on its average monomer number of about 1. The tartaric acid was used to acidify the impregnation-30 solution. Em. the stock solutions were mixed in a volume ratio of 4: 1. Kraft paper (UG 70 g / m 2) was impregnated with the solutions thus obtained (pick-up 100%), and dried for 10 min at 160 ° C.

The papers were subjected to weight gain in impregnation, dry and wet tensile strength before fungus burial rot treatment as described above, and wet tensile strength after rot treatment. The test results are shown in the table below.

3 80741 I nPEG I Weight I_Tensile strength N / 60 mm_ (I I addition | before rotting | after rotting, wet I_ |% _ | dry | wet | 3 days | 5 days | 2 days | 14 days

5 | conceptual | | | I I I I I

| rot | - | 460 | 40 J 4 | - | - | “| | 2 j 1.95 I 420 j 268 j 180 j 172 j 145 j 31 | j 9 j 2.31 j 360 j 260 | 167 j 153 j 141 j 35 j

j 22 I 2.97 I 400 j 240 | 149 | 122 | 74 j 31 J

10 j 45 | 2.50 | 380 | 244 | 158 | 51 | 31 | 14 | I 181 f 2.71 j 348 | 248 j 157 j 102 j 54 j 8 | U_ | _l__I_I_I_I_I-1

It can be seen from the table that the rot resistance is reduced when higher molecular weight PEG is used.

Example 2

The solutions prepared according to Example 1, in which the monomer number n of PEG was 22, were mixed in different proportions. Impregnation and experiments were performed as in Example 1.

20 The test results are shown in the table below.

| DMDHEU- | Weight _Tensile strength N / 60 mm_ | solution: Appendix I before rotting. lahokäs. after, wet | PEG solution)% | dry wet 3 days and 5 days 2 days | i4vrk) 25 | (NPEG = 22) | _ | | _ | _ | | _ | | | 5: 0 I 1.94 | 420 | 268 | 162 | 146 | 142 | 66 | I 4: 1 | 2.97 | 400 j 240 j 149 j 122 j 74 j 31 | I 3: 2 I 3.98 j 420 j 240 j 131 j 74 j 37 j - j I 2: 3 j 4.97 j 404 j 196 | 117 j 38 | 8 | - j 30 j 1: 4 I 5.95 j 368 j 140 j 46 j 11 j - j - | | 0: 4 | 6.90 I 328 j 112 j 45 j 10 j - j - |

I 1-1-1_I_I_I_I_I

It can be seen from the table that the rot resistance deteriorated when 35 parts of PEG in the solution was added. The proportion of PEG solution is preferably about 10 ... 30%.

4,80741

Example 3

Solutions were prepared as in Example 1, except that the DMDHEU solution was Zn (NO 3> 2 * 4H 2 O 4 g / l) as a catalyst. It was impregnated as in Example 1 but the drying conditions were varied.

Heating____Tensile strength N / 60 mm_ | time heat before rotten. lahokäs. after, wet | min | status | dry wet 3 days and 5 days I 2 days I 14 days

ίο I_L2s_ | _ | _ | _ | _I_I_I

I 2 | 150 420 | 244 | 122 | 53 | 44 | 31 | j 4 | 150 410 j 266 j> 200 j> 200 j> 200 j 132 j j 10 I 165 I 363 j 265 j> 200 j> 200 j> 200 j> 200 j I_I_I-1_I_I_I_I-1 15

Using a Zn catalyst, better rot resistance was achieved than using a Mg catalyst.

Example 4

Solutions were prepared and impregnated as in Example 20 3, except that TMADU was used instead of DMDHEU. The experiments are shown in the table below.

| nPEG | Weight _Tensile strength N / 60 mm_ | | | addition [before rotting lahokäs. after, wet 25 | __ | % _ | dry wet 3 days | 5 days | 2 days | 14vrkj | 2 and 150 464 j 189 | 39 j 32 | 30 j 26 | | 4 j 150 | 452 j 169 | 101 j 82 j 80 j 64 j j 10 | 165 j 404 j 260 j> 200 j> 200 | > 200 j> 200 j

I__J_l__I_I_I_I__ | _I

Thus, TMADU did not have as good rot resistance as DMDHEU.

Example 5

Impregnated according to Example 2 with different ratios of li-35 with a monomer number of PEG of 45. The refractive index of the papers was determined. The results are shown in the table below.

Il 5 80741 I DMDHEU-1 solution: | _Ta ittoluku_j I PEG solution_I machine direction [cross direction_j I untreated | 1105 | 675 | 5 I 5: 0 I 70 I 66 j I 4: 1 I 220 I 161 | I 3: 2 I 415 | 183 | I 2: 3 I 440 | 286 | I 1: 4 I 1185 | 462 | 10 I 0: 5 I 1350 | 530 |

I_I_I_I

It can be seen that the increase in the amount of PEG increased the double-fold strength.

15 Example 6

Impregnated according to Example 2 with solutions of different ratios with a monomer number of PEG of 22. The papers were determined to have dry and wet tear strength. The results are shown in the table below.

20 _ | DMDHEU solution: | Tear strength mN_j | PEG solution_ [dry_ | wet [”| unprocessed 255 | 140 | | 5: 0 | 150 230 | 25 | 4: 1 | 220 | 265 | | 3: 2 | 230 | 295 | | 2: 3 | 240 | 335 | | 1: 4 | 240 | 340 | | 0: 5 | 200 | 180 | 30 (_ | _ | _ |

It can be seen that the modification reduced the dry tear strength but increased the wet tear strength.

Claims (9)

A modified cellulose-containing paper in which part of the hydrogen groups of the cellulose is substituted by an N-methylol compound, characterized in that the N-methylol compound is dimethyloldihydroxyethylene urea or tetramethylolacetylene diurea and that the paper further contains an organic polymer. Paper according to Claim 1, characterized in that the polymer is hydroxy-functional. Paper according to Claim 2, characterized in that the polymer is polyethylene glycol. Paper according to one of the preceding claims, characterized in that the N-methylol compound is present in an amount of 0.5 to 10% by weight of the paper. Paper according to one of the preceding claims, characterized in that the organic polymer is present in an amount of 0.5 to 10% by weight of the paper. Paper according to one of the preceding claims, characterized in that it additionally contains glyoxal. 6 80741 Coniferous cellulose-containing paper according to one of the preceding claims. 8. A process for preparing a modified cellulose-containing paper, wherein a part of the hydrogen group of the cellulose is substituted by an N-methylol compound, characterized in that the N-methylol compound is dimethylol dihydroxyethylene urea or tetramethylol acetylene diurea and that an organic polymer is added to the paper. 9. A seedling cell made from modified cellulose-containing paper, some of the hydrogen groups of which are substituted by an N-methylol compound, characterized in that the N-methylol compound is dimethyldihydroxyethylene urea or tetramethylol acetylene diurea and that the paper further contains organic. li 7 80741