CZ36796A3 - Increase of flour derivative retention in papers and cardboards by making use of polyethylene oxide - Google Patents

Abstract

The present invention relates to increasing the retention of various species powdered flour and starch and derivatives thereof in paper sheet for paper and board production. Flour, starch or derivatives thereof are treated phenolic resin solution before or in the time of their addition to the pulp. To the pulp polyethylene oxide solution is added. Flour or starch binds with phenolic resin and the resulting complex reacts with polyethylene oxide. The resulting chemical individual promote fiber flocculation, accelerate drainage pulp and increase fiber and fine retention shares in a paper sheet. The procedure represents a new mechanism for capturing and anchoring flour, starch or derivatives thereof in the resulting paper sheet. Drying through the passage part of the paper machine, the starch is turned into a liquid sebum, which creates bonds between the fibers. This process can be used to increase mechanical properties of paper and board in particular, the lag length, the burst strength a buckling strength.

Description

Increasing retention of flour derivatives in paper and board with polyethylene oxide

Technical field

BACKGROUND OF THE INVENTION The present invention relates to dewatering pulp and to increasing the retention of flour, fiber and fines in the paper sheet to the paper machine network in the manufacture of paper and board.

BACKGROUND OF THE INVENTION

Paper or board is produced by felting fibers on a paper or board machine. An aqueous suspension of different types of pulp flows to the screen of a paper or board machine where it is felted. Prior to this, these pulps are milled, optionally filled with various types of fillers, and various chemicals are added to give the final product the desired mechanical, optical, aesthetic and processing qualities. Various chemicals may also be added to the pulp to facilitate the manufacture of paper and / or cardboard and reduce production costs. One such group of chemicals are retention and drainage agents (ROPs). ROPs are used in these productions to facilitate dewatering of the pulp onto paper machine nets, while also favoring the retention of fine fiber, filler and colloidal materials in the paper sheet. These ROPs can be one-component (the resulting effect is produced by the addition of one chemical eg Al ₂ (SO ₄ ) ₃ , cationic starch, polyacrylamide, polyethyleneimine, polyamide etc. or two-component where the resulting effect is produced by reaction of two different chemicals. reacts with fibers and fines in two ways: the first is based on the interaction of chemical charges and fibers, the latter uses the high molecular weight of the chemical and the length of the molecule, and the resulting effect is called flocculation. is the increased rate of dewatering of the pulp onto the paper machine nets and also the increased retention of fines and colloids in the paper sheet Which type of reaction will predominate depends on the type of ROP Two-component ROPs are ROPs where the retention effect is produced by The reaction results in a new product having fiber flocculation properties and thus faster dewatering of the pulp and increased retention of fines in the paper sheet. An example of such a retention system would be a process utilizing a chemical reaction of polyethylene oxide with a phenol-formaldehyde resin or a process utilizing a reaction between polyacrylamide and bentonite. In modern production, a system is currently used where two or more types of ROP (usually a combination of fixation and flocculants) are combined with chemicals on the pulp to obtain the optimum result for each production. Examples of such combinations would be, for example, the use of polyethyleneimine and polyacrylamide, polyamide, and a process utilizing the reaction of phenol-formaldehyde resin and polyethylene oxide similarly.

A variety of methods and chemicals are currently used to enhance the mechanical properties of paper. Known are dry strength enhancers, which are mostly products based on polyacrylamide resins. Another widely used agent is cationic

- starch and / or natural powdered starch. The starch may be added either in the form of cooked starch to the pulp (eg cationic starch) or may be applied in a size press (eg boiled natural starch). When starch is added in the form of powdered starch, it is either sprayed onto the paper sheet at the time of its formation (single-screen paper machines) or added to the paper stock prior to inflow. The latter application, however, has an unpleasant economic and environmental impact. Unlike any of the foregoing methods, where starch has almost 100% retention in paper, the retention of powdered starch or flour may in some cases reach only 50%. Uncaptured starch cannot contribute to increasing the mechanical properties of the paper, but will in turn reduce the drainability of the stock. This reduces its attractiveness from a production and economic point of view. In addition, this non-retained starch or flour circulates in the sieve water of the paper machine and later becomes part of the wastewater and causes a significant increase in BOD ₅ values. This, of course, entails increased wastewater treatment costs and possibly a negative environmental impact.

SUMMARY OF THE INVENTION

The present invention relates to a method of application in which the flour and its derivatives, preferably starch and its derivatives (hereinafter starch), is mixed with a phenolic resin solution, preferably a phenol-formaldehyde resin solution, before or at the time of addition. starch into the pulp. A polyethylene oxide solution is added to the treated paper stock before it is discharged onto a paper or board machine screen. The starch binds with the phenolic resin and the resulting hybrid subsequently binds with polyethylene oxide. The high molecular weight compound formed by this reaction promotes flocculation of the fibers and hence dewatering of the pulp. By incorporating starch into the reaction between the phenolic resin and the polyethylene oxide, increased retention of starch in the paper sheet is achieved.

DETAILED DESCRIPTION OF THE INVENTION

Example 1:

The pulp was prepared by pulping 3-ply cardboard and its consistency was adjusted to 0.5%. Polyethylene oxide was prepared as a 0.1% solution. In the first phase, maize starch powder was added to 1 liter of 0.5% pulp so that the resulting starch dose was successively 0, 25, 50, 100, 150, 200 kg / t a.s of fibers. The fiber was mixed. The treated stock sample was filtered using a vessel having a 100 Mesch screen instead of the bottom. The stock was stirred vigorously during filtration. The first 250 ml of collected filtrate was brought to boiling and boiled for 10 minutes to convert the non-retained starch to a soluble form. The hot solution was filtered through coarse filter paper. A sample of the solution was analyzed for COD using the Hach colorimetric method.

Corn starch powder was mixed with a slightly diluted phenol-formaldehyde resin solution and added to 1 liter of 0.5% pulp to give a final batch of

The 3 phenol-formaldehyde resins were 200 g / t and the resulting starch dose was gradually 0, 25, 50, 100, 150, 200 kg / t a.s. fibers. To the treated sample was added 80 g / t per a.s. polyethylene oxide fibers in the form of a 0.1% solution. The fiber was mixed, processed and analyzed in the same manner as in the previous case.

Corn starch powder was added to 1 liter of 0.5% pulp so that the resulting starch dose was gradually 0, 25, 50, 100, 150, 200 kg / t a.s. fibers. The fiber was mixed. Subsequently, 200 g / t per a.s. of the diluted phenol-formaldehyde resin solution and the sample was mixed again. In the last step, 80 g / t was added per a.s. fibers of a 0.1% polyethylene oxide solution and the stock was mixed again. The paper suspension was processed and analyzed in the same manner as in the previous two cases.

A higher COD number means lower starch retention in the paper sheet. The results are shown in Table 1 and Figure 1.

Example 2:

The pulp was prepared by pulping 3-ply cardboard and its consistency was adjusted to 0.5%. Polyethylene oxide was prepared as a 0.1% solution.

In the first stage, maize starch powder was added to 1 liter of 0.5% pulp so that the resulting starch dose was successively 0, 25, 50, 100, 150 and 200 kg / t a.s. fibers. The fiber was mixed. The treated pulp samples were tested for dewatering time using a Schopper-Reigler apparatus according to the modified CSN 50 0290 standard. Dewatering time was measured as the time required to discharge 700 ml of water from 1 liter of paper suspension with a fiber concentration of 0.005.

In a second phase, the maize starch powder was mixed with a solution of a slightly diluted phenol-formaldehyde resin and the resulting suspension was added to 1 liter of 0.5% pulp so that the resulting dose of phenol-formaldehyde resin was 200 g / t a.s. fibers and the starch dose was successively 0, 25, 50, 100, 150 and 200 kg / t a.s. fibers. To the treated sample was added 80 g / t a.s. fibers of polyethylene oxide in the form of a 0.1% solution. The treated pulp samples were tested for dewatering time using a Schopper-Reigler apparatus according to the modified CSN 50 0290 standard. Dewatering time was measured as the time required to discharge 700 ml of water from 1 liter of paper suspension with a fiber concentration of 0.005.

In the third phase, the maize starch powder was admixed to 1 liter of 0.5% pulp so that the resulting starch dose was successively 0, 25, 50, 100, 150 and 200 kg / t a.s. fibers. The suspension was stirred. Subsequently, phenol formaldehyde resin was added to each sample in an amount of 200 g / t a.s. and the sample was mixed again. In the last step, a 0.1% polyethylene oxide solution was added to the treated samples so that the resulting polyethylene oxide dose was 80 g / t a.s. fibers. The sample was mixed. The treated pulp samples were tested for dewatering time using a Schopper-Reigler apparatus according to the modified standard ČSN 50 0290. Dewatering time was measured

-4 as the time required to discharge 700 ml of water from 1 liter of paper suspension with a fiber weight concentration of 0.005.

The lower the drainage time number, the higher the drainability of the stock. The results are summarized in Table 2 and Figure 2.

-5Table 1

Pulp -100% recycled box paper, fiber concentration 0.5%, temperature 20 ° C batch 200g phenol-formaldehyde resin and 80g polyethylene oxide per tonne a.s. fibers

Starch content in the sample % No ROP COD mg / l Škr + FFP + PEO COD mg / l <Škr + FFP> + PEO COD mg / l 0 211 198 198 2.5 273 254 211 5 331 329 259 10 442 505 276 15 Dec 575 681 315 20 May 701 986 358

Škr + FFP + PEO ** <Škr + FFP> + PEO

FFP

PEO

Sample where starch was added to the stock prior to the addition of FFP and PEO A sample that was processed by the method described in this patent, wherein the starch was mixed with FFP before being added to the stock.

Phenol-formaldehyde resin

Polyethylene oxide

Graph 1

Grafe. 1 FFP-PEO Box

Starch content%

No ROP

Conventional method

New method

Conventional Method A method wherein starch, FFP and PEO are added to the pulp independently.

New method A method of the invention.

-6Table 2

Pulp -100% recycled box paper, fiber concentration 0.5%, temperature 20 ° C batch of 200 g of phenol-formaldehyde resin and 80 g of polyethylene oxide per tonne a.s. fibers

Starch content in the sample % No ROP drainage time with / 700 ml Škr + FFP + PEO ** drainage time s / 700 ml <Škr + FFP> + PEO * drainage time s / 700 ml 0 32 18 18 2.5 35 18 18 5 37 19 Dec 20 May 10 42 22nd 23 15 Dec 49 25 28 20 May 58 26 30

Škr + FFP + PEO ** <Škr + FFP> + PEO

FFP

PEO

Sample where starch was added to the stock prior to addition of FFP and PEO A sample that was processed by the method described in this patent, wherein starch was mixed with FFP prior to addition to the stock.

Phenol-formaldehyde resin

Polyethylene oxide

Graph 2

Grafe. 2 FFP-PEO Box

-No ROP

- Conventional method

- A new method

Conventional Method A method wherein starch, FFP and PEO are added to the pulp independently.

New method A method of the invention.

-Ί Industrial applicability

The method of applying flour and its derivatives, in particular starches and their derivatives (hereinafter referred to as starches) according to the invention, will facilitate and extend the possibilities of their use and application in the production of paper and board. The increased retention of starches in the paper sheet made possible by the invention will positively affect the amount and quality of the bonds between the fibers of the resulting paper sheet and thereby have a positive effect on the mechanical properties of the paper or board produced. The high molecular weight compound formed by the reaction of starch-phenolic resin-polyethylene oxide can be used to facilitate dewatering of the pulp and to increase the retention of fibers and fines in the paper sheet to the webs of a paper or board machine.

Claims (2)

1. A method of applying powdered flour and its derivatives, in particular powdered starches and their derivatives, characterized in that the powdered flour or powdered starches and their derivatives are treated or mixed with a phenolic resin solution, preferably a phenol-formaldehyde resin solution, before and or at the time of adding these to the pulp and where a polyethylene oxide solution is added to the pulp and where paper and / or paperboard is produced from the pulp so treated on a paper or board machine. 2. A method of applying powdered flour or starch or derivatives thereof together with polyethylene oxide and phenol-formaldehyde resin to a paper suspension to increase fiber retention and fines and / or to increase the drainability of the paper web to a paper or board machine, characterized in that the flour or starch and their derivative is exposed to phenol-formaldehyde resin before or at the time of their addition to the pulp and where a polyethylene oxide solution is added to the pulp and where paper and / or paperboard is produced from the treated pulp on a paper or cardboard machine.