US2337887A - Paper and its production - Google Patents

Description

Patented Dec. 28, 1943 PAPER AND ITS PRODUCTION Otto Hansen, Mannheim, mann, Ludwigsha'fen-on heim, Germany, assi ments, to General Ani New York, N. Y.,

gnors,

line & Film Corporation, a corporation of Delaware and Hans Scheuer- -the Rhine Oggersby mesne assign- No Drawing. Application August 22, 1939, Serial No. 291,330. In Germany'August 25, 1938 I 6 Claims.

The present invention consists in a process for improving paper and paper obtainable according to this process. y

We have found that the compounds which are soluble or capable of swelling in water obtainable by the action of 'monohalogenacetic acid substances, i. e. monohalogenacetic acids or their salts, on wood pretreated with an alkali metal hydroxide are excellent assistants or improving agents for the preparation or finishing of paper. By treating the paper during its preparation or finishing with the said substances, paper with excellent properties is obtained. Such substances may be prepared for example according to the application Ser. No. 244,418, filed in the names of Michael Jahrstorfer and Julius Beck on December '7, 1938, now Patent No. 2,294,666, granted on September 1, 1942, preferably by means of monochloracetic acid or its alkali salts. The said substances are usually employed in the form of their water-soluble alkali salts.

These compounds, hereinafter referred to as wood ethers, may be used for example as addian aqueous solution of the alkali salts of the wood ethers and the web thus treated then being treated with a solution of a metal compound having a precipitant action, for example with an aluminium or titanium salt or an aluminium oxide sol solution, the insoluble salt of the wood ether thus being formed on the paper. Paper prepared in this way is distinguished by a high tensile strength, a better handle and a very good wet strength.

According to this invention it is possible to use in the improvement or finishing of paper products which cheap raw materials. Contrary to expectation the paper, cardboard, pasteboard and like products prepared with their aid are distinguished by a satisfactory fastness to light, which is the more surprising since ordinary wood is used as initial tions in the resin sizing of paper in pulp, The V amount of Wood ether added may be for example from 0.5 to 3 per cent or more with reference to the amount of air-dried fiber. By further working up there is obtained a paper which differs from papers prepared by the usual resin sizing methods in that it has a higher folding value, better tensile strength and generally higher mechanical strength,

The Wood ethers may also be used instead of the usual casein sizing (coating of the paper), for example by applying to the paper web after leaving the paper machine, for example in a brush coating machine, solutions of the alkali salts of wood ethers, if desired with an addition of the usual p gments.

In sizing in pulp or coating of the paper a precipitation or insolubilization of the wood ethers may be effected by an aftertreatment, as for example with aluminium or titanium salts. This may be effected with aluminium sulphate solutions or also with solutions of colloidal watersoluble aluminium oxide or also with titanium salt solutions. The treatment with the said metal compounds may also be carried out in the presence of protective colloids.

The aqueous solutions of the wood ethers are also suitable for the application of pigment suspensions to the paper web during its formation, as for example in the manner described in the German Patent 661,652. By aftertreating this infusion with aluminium or titanium compounds, the Wet strength of the paper maybe further in-' creased.

The wood ethers may also serve advantageously for the improvement of paper by the immersion process, the finished paper being introduced into material for the wood ethers.

The following examples will further illustrate how the said invention may be carried outin practice but the invention is not restrictedto these examples,

Example 1 To a paper pulp of per cent of bleached sulphite cellulose and 20 per cent of bleached straw cellulose in a hollander there is added 1 per cent of saponified resin size saponified to a degree of 80 per cent and employed in the form of a 50 per cent solution (with reference to the dry fiber substance). There is then added from about 0.6 to 1 per cent of the sodium salt of the wood ether prepared according to Example 1 j of the said application Ser. No. 244,418. The pulp is worked well in the hollander and after about 20 minutes 2 per cent of aluminium sulphate in solid or dissolved formare added. A valuable writing paper may be prepared from the pulp thus treated on the known paper machines.

Example 2 Eaiample 3 0.5 per cent of colophony in the form of its sodium soap is added to a paper pulp in a hollander. 3 percent of the sodium salt of the wood ether described in the foregoing examples are then added and, after thorough working, 4 per cent of aluminium sulphate. The paper pulp is worked up into paper in the usual manner, a product with excellent strength properties thus being obtained.

are very readily accessible from very E'zaniple4.-

1000 parts ofa titanium white-pigment con-' sisting of 90 per cent of titanium dioxide and 10 per cent of barium sulphate are kneaded with 4000 parts of blanc fixe and 2501pa1'tsfof talc' with the elder water. Into the resulting paste there are stirred 'lo .parts of a mixture consisting of montanic'acid and its sodium salt' and from 250 to 400 parts of the sodiumsalt of a.

wood ether previously dissolved in water. I

The mass thus obtained is adjusted to the viscosity necessary for application by the addition of water and applied in the usual way in a, brush coating machine to a paper web. The paper web thus coated is treated before or after drying with an aqueous aluminium sulphate solution containing about 10 grams of aluminium sulphate per liter for example by leading the paper web ac-. cording to the immersion process through the aluminium sulphate solution or spraying the latter onto the coated paper web through nozzles.

Example 5 2.5 kilograms of titahiumwhite pigment, consisting of about 9'0 per-cent of titanium dioxide and 10 per cent of varium sulphate, are made into a paste with 12 liters of water in a Ienart mixer. The aqueous suspension is th env introduced with rapid mixing into 140 liters of an aqueous starch solution containing 800 grams of potato-meal made into a paste. While stirring there are added to the mixture an aqueous solution of 120 grams of the sodium salt of a wood ether in 45 liters of water.

The suspension of titanium white thus prepared and stirred'is applied to the paperweb on the long sieve between the first and second suction portions. The water is thus sucked through the paperand passes belowthe paper web into the suction .devices while the pigment with the. greater part of the sodium salt of the wood etherand starch is retained by the swollen paper texture. The pigment is thus firmly cemented with the paper.-

A paper preparedin this way is eminently suitable-for printing and may serve as a substitute for coated paper.

If, under the above mentioned conditions, instead of 1.6 kilograms of titanium white pigment, there be used 2.2 kilograms of lithopone with a content of 60 per cent of zinc sulphide and 9.

- corresponding amount of blanc fixe, equally good coatings on paper are obtained.

- On the surface of the paper thus treated theremay be sprayed if desired before drying an about.

1 per cent solution of an aluminium oxide sol with the aid of a spraying device, the wood ether thus being converted into the insoluble aluminium salt. The paper thus prepared has good wet strength and is eminently suitable for printing.

Example 6 A finished paper web, after leaving the paper machine, is led through a 2 per cent aqueous that the wood ether is converted into its aluminiumsalt. The, paper thus obtained has a specially high tensile strength, a great folding value and avery good weti strength. Itgis therefore be" carried out in a single bath process withthe suitable for example for the preparation of waterproof bags.

The conversion into the aluminium salt may aid' of-protective colloids, as for example animal glue or-gum arabic.

What we claim is:

1. Paper of improved fastness to light, high folding value and w'et'strength which contains in the sizing aproduct obtainable by the action of a member selected from the group'consisting of a monohalogen acetic acid and a water soluble salt thereof on wood pre-treated withan alkali hydroxide and from which substantially no constituents have been removed by this pre-treatment.

2. A paper article as defined in claim 1 in which the said product is in the form of an alkali metal salt.

3. In the process for producing'paper products of improved fastness to light, high folding .value and wet strength, the step which comprises adding to the sizing of the paper material in the pulp a product obtainable by the action of a member selected from the group consisting'of a monohalogen acetic acid and a water soluble salt thereof on wood pre-treated with an alkali hydroxide and from which substantially no constituents have been removed by this pro-treatment.

4. Paper of-improved fastness to 'light, high folding value and wet strength which contains the reaction product, of an aluminumioxide sol on the product obtainable by the action of a member selected from the group consisting of a monohalogen acetic acid and a water soluble salt thereof on wood pretreated with an alkali hydroxide and from which substantially no constituents have been removed by'this pre-treat ment.

5. In'the process for producing paper products of 'improved fastness tolight, high folding value and wet strength, the step which comprises adding to the sizing of the paper material in the pulp, a product obtainable by the action of a monochloroacetic acid alkali metal salt on wood pre-treated with an alkali hydroxide and from which substantially no constituentshave been removed by this pr'e-treatment.

6. A process for producing paper of high wet and tensile strength,-folding value and fast'ness to light which comprises impregnating the paper with a product, in the form of its alkali'metal salt, obtainable by the action of a member selected from the group consisting f a monohalogen' acetic acid' and a water soluble salt thereof on wood pre-treated 'with an alkali hy-;

droxide'and from which substantially no constituents have been removed by this pre-treat-