JP2002520510A - Use of modified starch products as retainers in paper manufacturing - Google Patents

Abstract

  (57) [Summary] The present invention relates to the use of modified starch as a holding agent for pigments, inorganic fillers and fines in the manufacture of paper. The modified starch comprises at least one cationic polymer containing at least 20% by weight of a protonated or quaternized dialkylaminoalkyl (meth) acrylamide unit in a polymerized state, and at least one inorganic mineral It is obtained by decomposing starch, a starch derivative and / or a decomposition product thereof in an aqueous solution in the presence of a substance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD OF THE INVENTION

The present invention relates to starch or starch derivatives modified with a dialkylaminoalkyl (meth) acrylamide-based polyelectrolyte and pulped in the presence of an inorganic additive, in the production of paper, in the production of pigments, mineral fillers and fibrous It relates to the use as a retention agent for powders.

[0002]

[Prior art]

Pigments and fillers are added as essential paper components in the manufacture of the paper pulp dispersion and are combined in the paper formation with retention aids. Wochenblatt fur Papierfabr
According to ikation 5 (1991), pp. 149-154, for example, cationic coarse starch is widely used to improve the retention, drainage and strength of paper, especially Ullmann, 4th edn. The use of cationic starch ethers according to., 1979, Vol. 17, p. 581 improves the retention of pigments and fines.

[0003] Although the retention effect of starch ethers is limited, high molecular weight cationic polyelectrolytes with higher charge densities are also used as retention agents. For example, these high molecular weight polyelectrolytes include copolymers of acrylamide and an ester of (meth) acrylic acid with di (C ₁ -C ₂ ) alkylamino (C ₂ -C ₆ ) alkyl alcohol or acrylamide. Copolymers of (meth) acrylic acid with amides with di (C ₁ -C ₂ ) alkylamino (C ₂ -C ₆ ) alkylamines, each of which is present in a protonated or quaternized state Is mentioned. Such α, β-unsaturated N-substituted carboxylic acid amide-based holding agents are EP-A-0,
038,573.

According to WO 86/00100, in order to improve the retention, it is obtained on the basis of silicic acid whose surface has been modified with aluminum silicate and a cationic or amphoteric carbohydrate, preferably for example starch or amidopectin. Processes for producing paper are known in which a colloidal binder is added to the paper pulp.

[0005] EP-A-0,703,314 and WO 97/04168 use a special cationic amidopectin starch to improve retention, optionally but optionally with colloidal It has been suggested to use silicic acid, anionic polyacrylamide or bentonite.

[0006] Furthermore, Wochenblatt fur Papierfabrikation 20, 1994, pp. 785-790 discloses a particulate system as a retaining agent, in which paper pulp is first pretreated with cationic starch or cationic polyacrylamide. After flocking (aggregating), dispersing and then flocking again, the sheet is formed using a silica particulate system or by adding bentonite or aluminum salts. This multi-step processing mode improves the retention value.

Further, EP-B-0,227,465 describes a method for producing paper.
According to this, complex partial steps are used, in which the pulp and separately the mineral filler are first treated with a synthetic polyelectrolyte of the same charge, and then the filler thus treated is of the opposite charge. Is subjected to a treatment using a polymer polyelectrolyte.

[0008] Similarly, a multi-stage method for improving the retention is known from US Pat. No. 5,126,014, in which prior to any optional multi-stage shearing, Calcium carbonate as filler, cationic starch, cationic coagulant and anionic flocculant are added to the paper pulp, followed by at least one shearing step followed by bentonite or colloidal Add silicic acid.

[0009] Modification of starch products using cationic polyelectrolytes is also known in the prior art.

[0010] A process for the production of cationic starch is known from EP-A-0,803,512, according to which a dry starch together with a cationic polymer is heated for 10 minutes at a temperature of 60-200 ° C. Roast for 5 hours and use as paper strengthener.

[0011] Furthermore, modifying starch using ionic, especially cationic polyelectrolytes has been described in EP-B-0,282,761, WO 96/05373 and WO 96/1.
3525. For this purpose, according to EP-B-0,282,761, a cationic polymer of diallyldimethylammonium chloride, N-vinylamine or N-vinylimidazoline is heated together with raw potato starch or already pulped. . On the other hand, in WO 96/05373, a cationic polymer is preferably reacted with an anionic starch. And W
In O96 / 13525, a preferably hydrolyzed cationic polymer of N-vinylformamide, polyethyleneimine or polyalkylamine is reacted with starch, which may be of any type. These reaction products are only recommended as dry toughening agents for paper manufacture, as in starch modified with copolymers of (meth) acrylamide and dialkylaminoalkyl (meth) acrylamide.

[0012] Increasing amounts of waste paper and wood pulp dispersions are being used in the manufacture of paper, and the amount of cellulose short fibers and mineral fillers in the paper pulp dispersion is increasing. Further, in general, the amount of inorganic fillers and pigments must be further increased to obtain a paper having a commercially acceptable appearance. However, it is well known that the strength of paper is adversely affected with increasing amounts of fines, especially mineral fillers and pigments. That is, for example, K. Ritter and H. Forkel, "Papiefaserstofftec
hnik "Symposium 1997, 21, p.4, paper tear resistance, a measure of paper strength, is considered to be a measure of the content of mineral fillers and pigments in paper. It is clear that it decreases with increasing ash content.

[0013]

[Problems to be solved by the invention]

It is therefore an object of the present invention to reduce the mechanical strength of paper in known paper making, preferably in such paper making using waste paper, without additional processing steps, i.e. without the partial steps mentioned above. It was to improve the retention of pigments, fillers and powders without having to compromise.

[0014]

[Means for Solving the Problems]

According to the invention, this object is achieved by using the modified starch as a holding agent for pigments, inorganic fillers and fines in paper production. At this time,
This modified starch comprises starch, a starch derivative and / or a decomposition product thereof,
The presence of at least one cationic polymer in the aqueous solution comprising at least 20% by weight of polymerized dialkylaminoalkyl (meth) acrylamide moieties in the protonated, preferably quaternized state; This is achieved by the use described above, which is obtained by pulping underneath, and further adding at least one inorganic mineral-based particulate additive before, during or after pulping.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

The following are used as starch components. Raw starch, such as potato starch, wheat starch, cereal flour, corn starch, tapioca starch, sago starch, as well as starch with increased hydrolysis, rice starch,
Peanut starch and / or mixtures thereof; starch degradation products, especially dextrins, or starch derivatives such as oxidized starch, for example dialdehyde starch, chemically modified starch, especially anionic starches, for example carboxy Degraded with starch and persulfuric acid (degraded
) Starch, anionic starch ethers such as starch phosphate mono- or diesters, starch acetate and starch citrate, anionic starch ethers such as carboxymethyl starch, carboxymethyl-2-hydroxyethyl starch or carboxymethyl-3-hydroxypropyl starch Or cationic starch derivatives such as N-containing starch ethers, especially primary or secondary amino or imino groups, tertiary amino groups positively charged by protonation with acids, and quaternary ammonium groups. It is a starch which has.

Preference is given to raw starches such as potato starch, wheat starch, corn starch, rice starch, peanut starch and / or mixtures thereof, and anionic and / or cationic N-containing starch ethers.

As the cationic polymer, (meth) acrylic acid and / or acrylic acid,
Preferably, the amide moieties in the polymerized state with di (C ₁ -C ₂ ) alkylamino (C ₂ -C ₆ ) alkylamine, each of which is present in a protonated or quaternized state, are at least 20. A homopolymer or copolymer of dialkylaminoalkyl (meth) acrylic amide, which is contained by weight, is preferably used. These processes are for example reported in EP-A-0,013,416 or EP-A-0,113,038, the corresponding disclosures of which documents are hereby incorporated by reference.

These polymerized moieties may be protonated or quaternized N-dialkyl-substituted (meth) acrylamides, such as dimethyl, which has been reacted with a well-known quaternizing agent. Aminoethylacrylamide or -methacrylamide, dimethylaminopropylacrylamide or -methacrylamide, diethylaminopropylacrylamide or -methacrylamide, diethylaminoethylacrylamide or -methacrylamide, diethylaminomethylacrylamide or -methacrylamide, and N ', N'-dimethylamino It is preferably derived from -2,2-dimethylpropylacrylamide or -methacrylamide or a mixture thereof. For example, dimethyl sulfate, diethyl sulfate, methyl chloride, ethyl chloride,
Preferably dimethyl sulfate or methyl chloride is possible as quaternizing agent.

The polyelectrolyte can include, as additional moieties, a moiety of an unsaturated monomer, for example, diallyldimethylammonium chloride. These monomers incorporated by polymerization may be water-soluble, non-ionic monomers such as acrylamide, methacrylamide, N- (C ₁ -C ₂ ) alkylation (
(Meth) acrylamide, N-vinylamide, vinylformamide, N-vinylacetamide, N-vinyl-N-methylacetamide, N-vinylpyrrolidone and the like. Furthermore, suitable water-soluble monomers, partially or completely esterified with C ₁ -C ₄ monohydric alcohol, N- methylolacrylamide, N- methylolmethacrylamide, and with N- methylol (meth) acrylamide is there.

The copolymer may also comprise a limited amount, preferably up to 10% by weight, of a poorly water-soluble and / or water-insoluble monoethylenically unsaturated monomer, as long as the solubility of the copolymer in water is maintained. For example, it may contain an alkyl (meth) acrylate or vinyl acetate.

The polymer product used according to the invention has a molecular weight of m. w. (G / mol) is 1.
0 × 10 ⁵ to 40 × 10 ⁶ , more preferably 2.0 × 10 ⁶ to 15 × 10 ⁶ , particularly preferably 5.0 × 10 ⁶ to 15 × 10 ⁶ .

The viscosity was measured using a 1% polymer solution dissolved in a 10% NaCl solution, using a Brookfield RVT viscometer to measure the spindle 1-3 / 10 r. p. m. At 2
It was measured at 0 ° C. and showed> 10 mPa · s for the polymer used.

As the inorganic mineral-based finely divided additives, clay, preferably swellable,
Silicic acid, preferably silicic acid sol, and / or aluminum-modified polysilicate, polyorthosilicic acid, aluminum-modified polyorthosilicic acid, bentonite, titanium dioxide, or talc can be used. That is, the inorganic mineral substance may be composed only of these. These substances are preferably present as microparticles or microgels. In particular, bentonite,
It is preferred to use talc, titanium dioxide or silicate sol.

The reaction of the starch component with a cationic homopolymer or copolymer of a preferably protonated or quaternized dialkylaminoalkyl (meth) acrylamide is carried out in an aqueous dispersion in a reaction vessel. In a batch mode or in a continuous flow mode, for example in a jet boiler, at 70-130 ° C., preferably 90-10 ° C.
By subjecting to heat at a temperature of 0 ° C., the abovementioned inorganic additives can be added, optionally under pressure, thus pulping the starch component. The reaction conditions and appropriate equipment-related conditions are described in Wochenblatt fur Papier 4, 1991, pp. 127-13.
Follow what is described in 0. The description of the document is incorporated herein by reference.

Before the pulping of the starch or during the pulping of the starch, preferably prior to the modification reaction and the pulping with a cationic homopolymer or copolymer, from 0.1 to 0.1% based on the pulped starch component. 15% by weight, preferably 3 to 15% by weight,
The addition of inorganic mineral based additives, more preferably in an amount of from 5 to 13% by weight, results in a retention agent with improved effectiveness with respect to its ability to retain fillers and powders.

The aqueous dispersion of the starch component, which has been used for the above-mentioned modification and has not been pulped, preferably contains 0.5 to 20% by weight of the starch component, more preferably 0.5 to 10% by weight. %, More preferably 2.0 to 10% by weight. The aqueous solution of a polyelectrolyte used for this modification has a cationic homopolymer or copolymer content of 0.1 to 2.0% by weight, preferably 0.1 to 0% by weight.
. The content is 5% by weight, more preferably 0.1 to 0.3% by weight. In this modification, the weight ratio of starch component to cationic polyelectrolyte ranges from 4: 1 to 25: 1, preferably from 10: 1 to 25: 1, more preferably from 14: 1 to 20: 1. Range.

The modified starch products described above, together with inorganic additives, preferably in the form of aqueous solutions, can be used as holding agents in the production of all grades of paper and paperboard.
They are preferably suitable for the production of bleached or unbleached sulphite or sulphate cellulose papers. Such fibrous materials may be made of up to 100% by weight of wood pulp and / or waste paper and have high levels of inorganic fillers, pigments and fibrous powders for this reason only.

According to the invention, the retentive agent of the invention is used in the aqueous paper pulp dispersion in a solids content of 0.1 to 10% by weight, preferably 0.5 to 5% by weight, based on dry matter, ie paper pulp. weight%,
More preferably, it is added in an amount of 1.0 to 3% by weight of solids upstream of the stock inlet of the paper machine, preferably as an aqueous solution, with stirring. This addition includes calcium carbonate, kaolin, aluminum silicate and aluminum oxide hydrate,
It is performed on or with aqueous dispersions which may contain satin white, talc, gypsum, barite, calcium silicate, lithopone and diatomaceous earth as fillers and also synthetic organic fillers from recycled materials. They may be added together.

The retaining agent of the present invention is advantageously added to the pulp dispersion in the machine chest upstream of the vertical separator and upstream or downstream of the stock flow pump prior to sheet formation.

The use of the retention agent of the present invention based on modified starch and inorganic additives achieves an excellent filler retention and surprisingly increases the filler and consequently the ash content of the paper. Nevertheless, deterioration of numerical values indicating strength can be avoided. This is especially the case when using paper pulp dispersions which contain a certain amount of wood material or waste paper, such as wood pulp and thermomechanical pulp (TMP) or waste paper.

It has also been found that the use of the retaining agent of the present invention does not interfere with the effect of the optical brightener added to improve the whiteness of the paper pulp.

The present invention will be described in more detail with reference to the following examples.

【Example】

Examples 1-4 A In a heatable container, raw potato starch (product name C ^* Gel30002, Co. C
250 g of a 4.0% by weight aqueous dispersion of erestar Holding BV) were mixed with 250 g of a 0.25% by weight solution of a water-soluble cationic polymer with stirring, and then various amounts of bentonite were added each with talc. And then heated at a temperature of 95-100 ° C. In Comparative Example 1, no mineral substance was added. The mixture was maintained in the above temperature range for 15 to 20 minutes, then cooled and used as a holding agent. A copolymer of trimethylammonium propylacrylamide chloride and acrylamide containing 70% by weight of a quaternized monomer was used as a water-soluble cationic polymer.

B. A 4.0% by weight pulp dispersion consisting of 100% by weight of waste paper was diluted with water to a concentration of 1% by weight, and the holding agent prepared in A was added thereto with stirring. The retention agent was added in an amount of 2.125% by weight based on the dry matter of the pulp dispersion.

Using the pulp dispersion obtained in CB, about 100 g in the laboratory
A test sheet having a gram weight of / cm ² was prepared. This creation is DIN5
Rapid-Kot on Haage sheet former model 20-12MC according to 4358
Made using the hen method. These sheets were dried and stored overnight under standard conditions of 23 ° C. and 50% relative humidity.

After weighing the paper, the gram weight, ash content and the bursting pressure according to DIN 54373 and DIN 63141 were determined.

The overall retention indicates the ratio of the amount of dry material used in paper manufacture to the amount of material remaining in the final paper. This can be measured by weighing the respective amount of the material.

The ash retention indicates the ratio of ash contained in the amount of (dry) material used to make the paper to the ash of the final paper. This is determined by measuring the respective ash content.

The fines retention was used in the paper production relative to the fines content of the final paper (
(Dry) means the ratio of fines content to the amount of material.

The respective amount of fines is measured using a brit dynamic drain jar as follows.

An aqueous suspension of paper pulp containing 0.5 g of dry paper material (paper is made from this suspension (StWG)) is diluted to about 1% by weight using tap water. 750r of this suspension
After stirring for several seconds at pm, drain with stirring. Another 500m of water in the residue
Add, stir and drain. This process is repeated until the filtrate is completely clear.
That is, repeat 4-5 times until the fine fibers are no longer washed out. The residue on the screen is placed on a weighed filter and weighed (dry at 110 ° C.).
Measure.

Calculation of fines content: Fines content = 100−amount of coarse material (%)

The amount of coarse material corresponds to the amount of fiber present on the filter.

[0043]

(Equation 1)

The corresponding values obtained from Comparative Example 1 and Examples 1-4 are shown in Table 1.

[0045]

[Table 1]

Comparative Example 2 The methods A, B and C of Examples 1 to 4 were the same, but the cationic polymer specified in A of Examples 1 to 4 was used as it was as a retention aid in sheet formation. The corresponding values are shown in Table 2.

[0047]

[Table 2] * Without starch component

[Procedural Amendment] Submission of translation of Article 34 Amendment of the Patent Cooperation Treaty

[Submission date] October 23, 2000 (2000.10.23)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

──────────────────────────────────────────────────続 き Continuation of front page (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE ), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN , CU, CZ, DK, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, S SI, SK, SL, TJ, TM, TR, TT, UA, UG, US, UZ, VN, YU, ZA, ZW (72) Inventor Fischer, Ulrich Germany Strasse 44 (72) Inventors Hartan, Hans-Georg Germany Kevera-Day 47625, Langstraat 1F-term (reference) 4L055 AA11 AC09 AG18 AG19 AG26 AG27 AG47 AG48 AG73 AH01 AH18 AH50 BD11 EA20 EA30 EA32 FA10 FA13

Claims (17)

[Claims] 1. Use of a modified starch as a retention agent for pigments, inorganic fillers and fines in paper manufacture, the modified starch comprising starch, starch derivative and / or starch.
Or pulping the decomposition product thereof in an aqueous solution in the presence of at least one cationic polymer comprising at least 20% by weight of a polymerized dialkylaminoalkyl (meth) acrylamide moiety; The use according to the above, characterized by being obtained by adding at least one kind of a fine particulate additive based on a mineral substance. 2. The use according to claim 1, wherein the protonated or quaternized di (C ₁ -C ₂ ) alkylamino (C ₂ -C ₆ ) alkyl (meth) acrylamide moiety is a dialkyl. Use characterized by being present as an aminoalkyl (meth) acrylamide moiety. 3. Use according to claim 1 or 2, wherein dimethylaminoethylacrylamide or -methacrylamide, diethylaminopropylacrylamide or -methacrylamide, diethylaminoethylacrylamide or -methacrylamide, diethylaminomethylacrylamide or -methacrylamide. Quaternized and polymerized dimethylaminopropylacrylamide or -methacrylamide, dimethylaminomethylacrylamide or -methacrylamide, N, N-dimethylamino-2,2-dimethylpropylacrylamide or -methacrylamide, or a mixture thereof The part in the state is a quaternized di (C ₁ -C ₂ ) alkylamino (C ₂ -C ₆ ) alkyl (meth) acrylamide part Use characterized by being present as minutes. 4. Use according to claim 3, wherein said moiety has been reacted with a quaternized compound, dimethyl sulfate or methyl chloride. 5. Use according to one or more of the preceding claims, wherein the trimethylammonium propylacrylamide chloride moiety is present as a quaternized dialkylaminoalkylacrylamide moiety. Characterized by the use. 6. Use according to one or more of claims 1 to 5, wherein the cationic polymer is an ether, preferably partially or completely, of a water-soluble unsaturated monomer. Α, β-unsaturated amide, N-vinylamide, which may be
Use of an N-hydroxyalkylamide; N-vinylpyrrolidone; and / or a dialkyldimethylammonium chloride, further comprising a part in a polymerized state. 7. Use according to claim 6, wherein the amide moiety is derived from acrylamide or methacrylamide, preferably acrylamide. 8. Use according to one or more of claims 1 to 7, wherein the cationic polymer is a water-insoluble or water-insoluble α, β-unsaturated monomer, preferably The use of (meth) acrylic acid alkyl ester or vinyl acetate, characterized in that the content thereof is not more than 10% by weight. 9. Use according to one or more of claims 1 to 8, wherein the molecular weight of the cationic polymer is m.p. w. (G / mol) 0.1 to 20,000,000. 10. Use according to one or more of claims 1 to 9, wherein the starch is native starch, preferably potato starch, cereal f.
lour), wheat starch, corn starch, rice starch, peanut starch, and / or mixtures thereof, or an anionic starch or a cationic N-containing starch ether. 11. Use according to one or more of the preceding claims, wherein the starch component is at least one additive of inorganic mineral substance system, preferably clay, silicic acid (modified with aluminum). Or pulping in the presence of fine particles of polysilicate (which may be modified with aluminum) or polyorthosilicate, bentonite, titanium dioxide or talc. 12. Use according to one or more of the preceding claims, wherein the inorganic additive is used in an amount of 0.1 to 15% by weight, based on the modified starch component. Use characterized by being done. 13. Use according to one or more of claims 1 to 12, wherein the weight ratio of starch component to cationic homo or copolymer is 4: 4 in performing said modification. 1
２５25: 1, preferably 10: 1 to 25: 1, more preferably 14: 1 to 20:
Use characterized by the range of 1. 14. Use according to one or more of claims 1 to 13, wherein the starch component is pulped at a temperature of 70 to 150 ° C, preferably 90 to 100 ° C. Use characterized by that. 15. The use according to one or more of claims 1 to 14, characterized in that said retaining agent is added to the paper pulp suspension before the formation of the sheet. use. 16. Use according to one or more of claims 1 to 15, wherein the retaining agent is:
Use characterized in that it is added in a solids content of 0.1 to 10% by weight, preferably 0.5 to 5% by weight, based on the paper pulp. 17. Use according to one or more of the preceding claims, characterized in that used paper is used for the production of paper.