DE1260964B - Process for the production of paper that is dimensionally stable when exposed to moisture - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

Number:
File number:
Registration date:
Display day:

D 21h

German class: 55f-16

1260 964
E 18522 VI b / 55 f November 18, 1959 February 8, 1968

The invention relates to a method for the production of dimensionally stable under the action of moisture and strong, water-vapor-permeable paper, which is used in particular as a support for light-sensitive layers suitable is.

As is known, paper is made from cellulose fibers, in particular wood pulps, by a Slurry of fibers is applied to the wire of a paper machine, from where the wet formed Paper web fed with felt-covered rollers and then on steam-heated drums is dried. If the paper is to have a particularly smooth surface, then it will still rolled smooth in the calender. To improve the properties of the papers, these or the Fibers are treated or mixed with sizing agents before they are processed into paper. the end Partially acylated, in particular acetylated, cellulose fibers produced paper has the disadvantage that it is often opposes the known gluing process.

Papers intended for special purposes can then be treated with a wide variety of impregnating agents be treated afterwards.

From US Pat. No. 2,069,771 it is known to write papers which are made from a continuous cellulose derivative phase and fibers embedded therein, entangled with one another, with an alcoholic Solution of a mixture of a cellulose ester of at least one lower fatty acid and of one To treat plasticizers for this cellulose ester, then to evaporate the alcohol and that Heat treatment of paper. In this process, the waterproofing agent is only used applied to the surface of the paper. The paper produced in this way is impermeable to water vapor and water repellent. The paper is practically a plastic film filled with felted fibers represent.

The object of the invention is to provide a particularly dimensionally stable and moisture-insensitive material which is suitable for photographic purposes Specify paper based on partially acylated cellulose fibers, its wet strength and folding values with the corresponding values of commonly used as photographic supports papers used are comparable or even cheaper.

It has surprisingly been found that a paper of the desired properties can be obtained by treating of partially acylated cellulose fibers having an acetyl content from 15 to _30/0 ° paper produced with an alcoholic solution of a Celluloseesters and a plasticizer.

Process for the production of paper that is dimensionally stable when exposed to moisture

Applicant:

Eastman. Kodak Company,

Rochester, N. Y. (V. St. A.)

Representative:

Dr.-Ing. W. Wolff and H. Bartels, patent attorneys,

7000 Stuttgart N, Lange Str. 51

Named as inventor:
Carl Johan Malm,
Lloyd Emerson Herdle,
Gerald Clifford Gandy,
Rochester, NY (V. St. A.)

Claimed priority:

V. St. v. America January 12, 1959 (786 043)

The invention therefore relates to a process for the production of under the action of moisture Dimensionally stable and strong, water-vapor-permeable paper, which is used in particular as a carrier for light-sensitive Layers is suitable, using a paper with an alcoholic solution of a mixture a cellulose ester of at least one lower fatty acid and a plasticizer for this Cellulose ester treated and then the alcohol is evaporated away, characterized by that with the alcoholic, about 10 to 25% igen (based on the ester and plasticizer content) Cellulose ester solution consists essentially of partially acylated, especially acetylated cellulose fibers Paper with an acyl content of about 15 to 30% is so impregnated that less than 1 part Solution per 1 part of paper is added.

809 507/584

3 4

Heat that which can be made by the method of the invention to remove the moisture. Example paper has good wet strength, in a favorable manner the paper can have properties and good burst strength before the treatment and is ^{exposed to a temperature of at least about 49 °} C. for water vapor to be easily permeable. The upper temperature limit depends to an essential part on the temperature, which can be produced by the process of the invention, at which paper is particularly suitable as a carrier for photographic properties of the paper, graphic halogen silver emulsion layers. Any desired cellulose ester can be used as a plasticizer, the paper being plasticized beforehand in a known manner. The percentage covered with a layer of barite. The paper plasticizer can also make up about 20 to 75%, based on the bleached cellulose ester-plasticizer mixture which is then expedient in this case. Pulp produced. The paper which can be produced according to the process of the particularly advantageous plasticizers are example invention, however, is also suitable as dibutyl phthalate, dibutyl sebacate, dioctyl phthalate for packaging purposes, for electrical insulation and dibutyl adipate.

purposes and can also be used in all cases. The Erin to which the moisture absorption and the perception of paper made from partially acetylated cellulose fibers Resistance to sources as well as those treated with an acetyl content of 15 to 25%, durability under the action of moisture from If the used according to the invention partially meaning are. esterified fibers contain acyl groups other than acetyl groups, such as propionyl or butyryl groups, which can be prepared by the process of the invention, then Paper can be obtained on the basis of such papers, they should have an apparent acetyl content of 15 to 20 which are partially acylated in a known manner from 25%.

Cellulose fibers are produced. The Partial Suitable Alcohols for the Preparation of the Imprä-Acylation of cellulose fibers, for example, gnierungslösung are in particular those with up to described in Canadian Patent 649,270, 4 carbon atoms, such as n-butyl alcohol, isobutylder British patent 367 312 and in the time 25 alcohol, n-propyl alcohol, isopropyl alcohol, ethyl script "Industrial and Engineering Chemistry", Vol. 35 alcohol and methyl alcohol. These alcohols take over like that (1943), pp. 1206 to 1210. After the partial acetyl there was almost no swelling effect on the partially acetylated Keren are the cellulose fibers after any fiber, which has the particular advantage that the customary papermaking processes for sheets use only minimal amounts of alcoholic fibers is working. According to the invention, such a solution will now be picked up. While z. B. when using Paper after drying with an alcoholic certain other solvent up to -4 parts of the Solution of a cellulose ester and a soft solution are retained by the paper, which holds macher impregnated. After exposure to pressure, less than 1 part of said alcoholic fiber for example by means of press rollers, and evaporating the solution per part of the paper back. Preferably The paper is heated under pressure with alcohol, butyl alcohol is used for it.

to give a smooth finish. In order to prevent that the paper loses its opacity, the process of the invention can be carried out in such a way that the paper contains a pigment, e.g. B. titanium dioxide, a solution of the cellulose ester and the plasticizer are incorporated, as it is immersed, for example, in the USA. This means that the patent specification 3,057,755 is described. 40 can lead through an appropriate bath. The many processes which can be carried out continuously for the partial acylation of wood pulp are known to lead to a reduction in the fiber strength when a paper roll is continuously unwound. The result of this being heated and in a bath of the alcoholic solution is that the paper produced from the acylated fibers and continuously placed therefrom by pressure rollers is less firm than the paper made from non-drawn, freed from alcohol by evaporation and acylated fibers . Is passed indifferently over hot calender rolls, whereby it is now, whether through the partial acylation the strength to achieve a smooth surface, which has been reduced against wetting of the fibers or not, is stable with water and renewed drying, carrying out the method of the invention a is exposed to a heat treatment under pressure, partial effect on the properties of the 50. Since the paper is not swollen, the amount of paper is reached. of the solution remaining in the paper is less than The method of the invention results in an equal to 1 part per part of the paper. After the evaporation of the moderate distribution of the cellulose ester and the soft alcohol, the amount of the usual paper maker is in the paper. The cellulose esters easily adhere to the thickness and absorption power of the remaining cellulose of the fibers, since they generally have less affinity than fibers to the partially acylated cellulose esters and plasticizers. The alcohol ^{is preferably 1} part per part of the paper and is preferably in solution as a cellulose ester, at least partially of the order of magnitude of ¹ J ₁₀ parts per part of paper, substituted with propionyl and / or butyryl radicals. If ethyl alcohol is used as the solvent, cellulose is used . A certain acetyl content is so that more alcoholic solution can be carried through the paper, but the cellulose ester must have a propionyl or butyryl content that is sufficient than when using higher alcohols, for example 3 or 4 carbon atoms, so that it is easily soluble in hot alcohol is. If the following examples are intended to illustrate the process in which the alcoholic solution is only liquid at elevated temperature, it is advisable to first heat the paper before subjecting it to treatment with the solution 65 Example 1. In the case of alcohols that are not well tolerated by water, such as butyl alcohol, it is just the same. First, a paper weighing, if recommended, the paper at least initially about 97.6 grams per square meter of bleached, up to

an acetyl content of about 20% acetylated kraft pulp. This paper was made from a solution of 75% n-butanol, 12.5% cellulose acetobutyrate (butyryl content 35 to 59%, acetyl content 12 to 15% -817-56) and 12.5% dibutyl phthalate. The paper was then passed through squeeze rollers to squeeze the liquid, leaving about V ₂ parts of solution per part by weight of paper pulp. The alcohol was then driven from the paper by means of a stream of warm dry air. Finally, the paper sheet was calendered at 60 ° C. in four passes between pairs of rollers. One roller was made of a steel roller and the other was made of a softer material.

The same process was repeated with a paper prepared as indicated, in its bulk however, before processing on the wire of the paper machine, 1% melamine-formaldehyde resin was incorporated became.

The following table shows the differences in physical properties between

ίο the paper made by the method of the invention has been treated with an alcoholic solution of cellulose ester and plasticizer, and the paper, that has not been treated that way. The paper containing the melamine-formaldehyde resin was made referred to as wet strength paper.

Table I.

Characteristic values to be compared Wet strength paper

before the
treatment

after
treatment

Glue-free paper

before treatment

after treatment

Tear strength L (in g)

Tear strength Q (in g)

Burst strength *) (kg / cm ² ) ...

Wet strength (kg / cm ² )

Linear wet elongation (in%)

Folding strength **) L

Folding strength **) Q

56
60
3.29
2.31
0.80
163
232

68
1.05 0.158 2.05

11
9

56 56 2.73 1.12 0.75 264 203

*) Determined according to ASTM method D 774-63T. **) Determined according to ASTM method D 2176-63T.

In the table above, L means that it was calendered in longitudinal roller pairs. Using direction and Q in the transverse direction made 45 of a paper made of only Jordanized fibers Measurements on paper. the following results were obtained:

Example 2

First, a paper weighing about 97.6 grams per square meter was made from bleached kraft pulp which has been acetylated to an acetyl content of about 20%. The paper was then passed through a solution of the following composition:

84% isobutyl alcohol,
10% cellulose acetobutyrate,
6% dibutyl phthalate.

The cellulose ester had a butyryl content of 38%, an acetyl content of 12% and a viscosity of 20 seconds.

The excess solution was removed by nip rollers, leaving about 60% solution based on the weight of the slurry. The alcohol was evaporated from the paper sheet, whereupon it was passed ^{through at about 6O 0} C and four times

Table II

characteristic

Tear strength L (in g) ..
Tear strength Q (in g) ..
Burst strength (kg / cm ² )
Wet strength (kg / cm ² )

Linear wet elongation

(in%)

Folding strength L

Folding strength Q

Before treatment

48
1.05 0.438

1.30 16 10

After treatment

52

48 2.45 1.24

1.00 56

45

When using a paper made of fibers that have been both Jordanized and ground, were at

7 8

Using different treatment solutions will get the following results:

Table III

before
treatment 90 isopropyl
5.0 cellulose
acetobutyrate **)
5.0 dibutyl
phthalate Treatment
Alcob
90 isobutyl
Estonian
5.0 cellulose
acetobutyrate **)
Soft ms
5.0 dibutyl
phthalate solution
oil,%
80 isobutyl
10 ethyl
r,%
5.0 cellulose
acetopropionate *)
Ier,%
5.0 dibutyl
phthalate 80 isobutyl
10 ethyl
8.0 cellulose
acetobutyrate **)
2.0 dibutyl
phthalate characteristic 60 after treatment after treatment after treatment after treatment Tear strength L (in g) .. 64 60 58 62 64 Tear strength Q (in g) .. 1.33 65 63 63 70 Burst strength (kg / cm ² ) 0.77 2.31 2.17 2.03 2.45 Wet strength (kg / cm ² ) 1.20 1.30 1.28 1.24 2.38 Linear wet elongation
(in ° / ") 16 1.05 1.15 1.05 1.00 Folding strength L (kg / cm ² ) 10 60 60 60 52 Folding strength Q (kg / cm ² ) 34 64 37 63

*) Propionyl content 45%, acetyl content 3.0 ° / _0; Viscosity: 20 seconds. **) butyryl content 38%, acetyl content 12%; Viscosity: 20 seconds.

Claims (6)

Patent claims: 1. A process for producing dimensionally stable and solid, water-vapor-permeable paper which is particularly suitable as a support for light-sensitive layers, wherein a paper is treated with an alcoholic solution of a mixture of a cellulose ester of at least one lower fatty acid and a plasticizer for this cellulose ester and then the alcohol weggedampft and the paper to a heat treatment is subjected to pressure, characterized in that a substantially acylated with the alcoholic, about 10 to 25 _^0/0 by weight (based on the ester and plasticizer content) Celluloseesterlösung of partially, particularly acetylated cellulose fibers existing paper with an acyl content of about 15 to 30% is impregnated in such a way that less than 1 part of solution per 1 part of paper is absorbed. 2. The method according to claim 1, characterized in that in the alcohol solution as a cellulose ester a cellulose which is at least partially substituted by propionyl and / or butyryl radicals is used. S. 3. The method according to claim 1 or 2, characterized in that the solvent for the Cellulose ester and the plasticizer butyl alcohol is used. 4. The method according to any one of claims 1 to 3, characterized in that as a plasticizer Dibutyl phthalate is used. 5. The method according to any one of claims 1 to 4, characterized in that a paper is used made from partially acylated cellulose fibers and bleached kraft pulp. 6. The method according to any one of claims 1 to 5, characterized in that the paper treated before evaporation of the alcohol with the alcoholic solution of the cellulose ester and the plasticizer is then passed through press rollers, such that only about ¹ I ₂ parts of solution per part Paper remains in this. Considered publications:
German Patent Nos. 909 653, 939 127;
U.S. Patent No. 2,069,771;
OhI, Impregnation of Paper and Cardboard (1954), 104, 105, 108.