WO2013079378A2

WO2013079378A2 - Method for producing filler-containing paper using biodegradable polyester fibers and/or polyalkylene carbonate fibers

Info

Publication number: WO2013079378A2
Application number: PCT/EP2012/073218
Authority: WO
Inventors: Gabriel Skupin; Rainer Blum
Original assignee: Basf Se
Priority date: 2011-12-01
Filing date: 2012-11-21
Publication date: 2013-06-06
Also published as: EP2785913A2; WO2013079378A3; CN103958772A

Abstract

The present invention relates to a method for the production of filler-containing paper, cardboard and paperboard, comprising the dewatering of a paper pulp with sheet formation and drying by adding biodegradable polyester fibers and/or polyalkylene carbonate fibers to the paper pulp.

Description

Process for the production of filler-containing paper using biodegradable polyester fibers and / or polyalkylene carbonate fibers

description

The present invention relates to a process for the production of filler-containing paper, cardboard and paperboard by adding biodegradable polyester fibers and / or polyalkylene carbonate fibers to a paper stock and dewatering the paper stock to form sheets and dry them.

In recent years, there have been many developments in increasing the filler content of papers. Filler-containing papers allow a reduction of the pulp content and thus lead to a reduction in manufacturing costs. Furthermore, they have the advantage of easier drying, which makes the papermaking process more economical.

However, the increase in the filler content in the paper on the other hand leads to altered paper properties such as reduced strengths. This problem has been addressed in the past by fillers modified with polymer solutions or dispersions.

The earlier WO application PCT / EP2012 / 060847 teaches biodegradable polyester polymer and / or polyalkylene carbonate polymer coated inorganic pigments which are used as fillers in the papermaking process.

Further, PCT / EP 2010/066079 teaches a method of sizing paper using biodegradable polymers as the polymeric sizing agent. These are useful both as a bulk and as a surface sizing agent. WO 2006/120700 teaches a method of producing high strength paper by applying a polymeric film to the wet paper sheet. The polymer also biodegradable polyesters such as Ecoflex ^® are called.

WO 201 1/073265 and WO 2008/140384 teach a process for producing filter media in which polylactic acid fiber and polyester fibers are mixed and processed into filters in a carding process. Filter papers contain no fillers.

DE 19931402 teaches filter materials of cellulose acetate fibers which have been modified with biodegradable, softening substances such as polyesteramides. The cellulose acetate fibers are for this purpose mixed with the softening substance. The filter papers are produced by applying to a layer of natural fibers the fibers thus blended are applied. The modified cellulose acetate fibers described herein are not biodegradable according to EN 13432 standard.

The present invention was based on a process for the production of filler-containing paper, cardboard and paperboard as an object that allows a weight reduction of the paper, cardboard or cardboard with the same properties, in particular the same strength. Furthermore, it should lead to good strength at the same or improved efficiency of the paper machine with high filler content of the paper products.

Accordingly, there has been found a process for producing filler-containing paper, board and paperboard comprising dewatering a stock under sheet formation and drying by adding biodegradable polyester fibers and / or polyalkylene carbonate fibers to the stock.

The present invention does not include filter papers. Under filter paper, the expert understands filler-free papers. These have sufficiently large pores that allow separation of the suspended particles from the liquid.

It has been found that the use of biodegradable fibers in the papermaking process leads both to good paper properties and additionally to an advantage in paper sheet formation. Thus, it is believed that the cross-linking of the fibers used in sheet formation with the cellulosic fibers results in partial or complete fusing in the subsequent drying and calendering process, thus providing additional strength.

Polyester fibers and / or polyalkylene carbonate fibers are to be understood below as structures whose length (longest extent) is many times greater than their diameter. The ratio of length to diameter is according to the definition of fiber> 5, preferably> 100 in particular ^ 2000 The diameter of the fibers is usually 3 to 100 μηη. Due to the small diameter, it is common to define fibers also by the fiber weight. Preference is given to using fibers having a fiber weight of from 0.1 to 100 dtex, in particular from 1 to 20 dtex (10 μηη to 45 μηη). This is understood to mean the weight of the fiber in grams at 10 km fiber length. The fibers are preferably used in lengths of 0.5 to 20 mm, preferably 1 to 10 mm. Shorter fibers are possible in principle, since they also lead to a strengthening effect. Likewise, longer fibers have no disadvantage on the resulting papers, but may optionally be worse dosed to the pulp. Fiber having a length in the preferred range of 0.5 to 20 mm has the added advantage that it is particularly well suited for sheet formation. If biodegradable polyester fibers and / or polyalkylene carbonate fibers are mentioned below, biodegradable polyester fibers and / or biodegradable polyalkylene carbonate fibers are to be understood by them. Under pulp, hereinafter a mixture of water and pulp is understood, which contains depending on the stage in manufacturing process of the paper, the cardboard or the cardboard in addition filler and optionally paper auxiliaries.

The dry content of the paper is understood as meaning the solids content of paper, board and pulp with the heat-barrier method as determined in accordance with DIN EN ISO 638 DE.

In the context of this application, the term pigment is used synonymously with the term filler, since in the production of paper the pigments are used as fillers. Under filler is, as usual in papermaking, inorganic pigment to understand.

The term "biodegradable" in the context of the present invention is then fulfilled for a substance or a substance mixture if this substance or the substance mixture according to DIN EN 13432, Chapter A.2 a percentage degree of biodegradation of at least 90% of a suitable Reference substance (eg, microcrystalline cellulose) has.

In general, biodegradability results in the polymers and polymer mixtures (hereinafter also abbreviated to polymer (mixtures)) decomposing in a reasonable and detectable time. Degradation can be effected enzymatically, hydrolytically, oxidatively and / or by the action of electromagnetic radiation, for example UV radiation, and mostly for the most part be effected by the action of microorganisms such as bacteria, yeasts, fungi and algae. The biodegradability can be quantified, for example, by mixing polymer (mixtures) with compost and storing them for a specific time. For example, in accordance with DIN EN 13432 (ISO 14855), C02-free air is allowed to flow through matured compost during composting and this treated compost is subjected to a defined temperature program. Here, the aerobic biodegradability is determined by the ratio of the net CO 2 release of the sample (after deduction of CO 2 release by the compost without sample) to the maximum CO 2 release of the sample (calculated from the carbon content of the sample) as a percentage of biological Definition defined. Biodegradable polymers (mixtures) usually show signs of degradation after just a few days of composting, such as fungal growth, cracking and hole formation. Other methods of determining biodegradability are described, for example, in ASTM D 5338 and ASTM D 6400-4.

Biodegradable polymers are already known to the person skilled in the art and are described, inter alia, in U-IImann ^'s Encyclopedia of Industrial Chemistry (online version 2009), Polymers, Biodegradable, Wiley-VCH Verlag GmbH & Co. KG, Weinheim, 2009, pages 131 disclosed. In particular, the term biodegradable polyester polymer in the context of the present invention includes biodegradable, aliphatic-aromatic polyesters as described in WO 2010/034712.

Biodegradable polyester fibers are preferably aliphatic polyesters or aliphatic-aromatic (partially aromatic) polyesters based on aliphatic and aromatic dicarboxylic acids and aliphatic dihydroxy compounds.

The fiber materials used according to the invention are preferably polyalkylene carbonates and aliphatic or aliphatic-aromatic (partly aromatic) polyesters based on aliphatic and aromatic dicarboxylic acids and aliphatic dihydroxy compounds. These polymers can be present individually or in their mixtures.

Preferably, the biodegradable polyester polymer and / or polyalkylene carbonate polymer is water-insoluble. In principle, all polyesters based on aliphatic and aromatic dicarboxylic acids and aliphatic dihydroxy compound, so-called partially aromatic polyesters or aliphatic polyesters of aliphatic dicarboxylic acids and aliphatic diols or of aliphatic hydroxycarboxylic acids are suitable for the preparation of the biodegradable polyester mixtures. Common to these polyesters is that they are biodegradable according to DIN EN 13432. Of course, mixtures of several such polyesters are suitable.

According to a preferred embodiment, at least one aliphatic-aromatic polyester polymer is used.

Aliphatic-aromatic polyesters are polyesters based on aliphatic and aromatic dicarboxylic acids and aliphatic dihydroxy compound, known as partially aromatic polyesters. According to the invention, polyester derivatives are to be understood here as well, such as polyether esters, polyester amides or polyetheresteramides and polyesterurethanes (see EP Note No. 10171237.0). Suitable partially aromatic polyesters include linear non-chain extended polyesters (WO 92/09654). Preferred are chain-extended and / or branched partially aromatic polyesters. The latter are known from WO 96/15173 to 15176, 21689 to 21692, 25446, 25448 or WO 98/12242, to which reference is expressly made. Mixtures of different partially aromatic polyesters are also possible. Interesting recent developments are based on renewable raw materials (see WO-A 2006/097353, WO-A 2006/097354 and WO 2010/034710). In particular, under partly aromatic polyesters products such as Ecoflex ^® (BASF SE) and Eastar ^® Bio to understand Origo- Bi ^® (Novamont).

Particularly preferred partially aromatic polyesters include polyesters as essential components

A) an acid component of a1) 30 to 99 mol% of at least one aliphatic dicarboxylic acid or its ester-forming derivatives or mixtures thereof a2) 1 to 70 mol% of at least one aromatic dicarboxylic acid or its ester-forming derivative or mixtures thereof and B) at least one diol component under C2 to C12 alkanediols and

C) at least one component selected from c1) a compound having at least three groups capable of ester formation, c2) a di- or polyisocyanate, c3) a di- or polyepoxide.

Suitable aliphatic dicarboxylic acids and their ester-forming derivatives (a1) are generally those having 2 to 18 carbon atoms, preferably 4 to 10 carbon atoms, into consideration. They can be both linear and branched. In principle, however, it is also possible to use dicarboxylic acids having a larger number of carbon atoms, for example having up to 30 carbon atoms.

Examples include: oxalic acid, malonic acid, succinic acid, 2-methylsuccinic acid, glutaric acid, 2-methylglutaric acid, 3-methylglutaric acid, o

Ketoglutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, brassylic acid, fumaric acid, 2,2-dimethylglutaric acid, suberic acid (suberic acid), diglycolic acid, Oxaloacetic acid, glutamic acid, aspartic acid, itaconic acid and maleic acid. The dicarboxylic acids or their ester-forming derivatives may be used singly or as a mixture of two or more thereof. Succinic acid, adipic acid, azelaic acid, sebacic acid, brassylic acid or their respective ester-forming derivatives or mixtures thereof are preferably used. Succinic acid, adipic acid or sebacic acid or their respective ester-forming derivatives or mixtures thereof are particularly preferably used. Succinic acid, azelaic acid, sebacic acid and brassylic acid also have the advantage that they are accessible from renewable raw materials.

Preferred are the following aliphatic-aromatic polyesters: polybutylene azealate-co-butylene terephthalate (PBAzeT), polybutylene-brassylate-co-butylene terephthalate

(PBBrasT) and particularly preferred: polybutylene adipate terephthalate (PBAT), polybutylene sebacate terephthalate (PBSeT) or polybutylene succinate terephthalate (PBST).

The aromatic dicarboxylic acids or their ester-forming derivatives (a2) may be used singly or as a mixture of two or more thereof. Terephthalic acid or its ester-forming derivatives, such as dimethyl terephthalate, is particularly preferably used.

In general, the diols (B) are selected from branched or linear alkanediols of 2 to 12 carbon atoms, preferably 4 to 6 carbon atoms, or cycloalkanediols of 5 to 10 carbon atoms.

Examples of suitable alkanediols are ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 2-butanediol, 1, 4-butanediol, 1, 5-pentanediol, 2,4-dimethyl-2-ethylhexane-1, 3 diol, 2,2-dimethyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 2,2,4-trimethyl- 1, 6-hexanediol, in particular ethylene glycol, 1, 3-propanediol, 1, 4-butanediol and 2,2-dimethyl-1, 3-propanediol (neopentyl glycol); Cyclopentanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol or 2,2,4,4-tetramethyl-1,3-cyclobutanediol. Particular preference is given to 1,4-butanediol, in particular in combination with adipic acid as component a1) and 1,3-propanediol, in particular in combination with sebacic acid as component a1). 1, 3 propandiol also has the advantage that it is available as a renewable resource. It is also possible to use mixtures of different alkanediols.

The preferred partially aromatic polyesters are characterized by a molecular weight (Mn) in the range from 1000 to 100,000, in particular in the range from 9,000 to 75,000 g / mol, preferably in the range from 10,000 to 50,000 g / mol and a melting point in the range from 60 to 170, preferably in the range of 80 to 150 ° C. Polyesters of aliphatic dicarboxylic acids and aliphatic diols include polyesters of aliphatic diols and aliphatic dicarboxylic acids such as polybutylene succinate (PBS), polybutylene adipate (PBA), polyethylene adipate (PEA), polybutylene sucocyanate adipate (PBSA), polybutylene succinate sebacate (PBSSe), polybutylene sebacate (PBSe) Polybutylene succinate adipate (PBSA), polybutylene succinate sebacate (PBSSe) and polybutylene sebacate (PBSe) are preferred aliphatic polyesters marketed by Mitsubishi under the name GSPIa. Recent developments are described in WO2010 / 034711.

The biodegradable polyesters may contain, in addition to or in place of the aforementioned aliphatic and aliphatic / aromatic polyesters, other polyesters such as polylactic acid, polybutylene succinates, polybutylene succinate-co-adipates, polyhydroxyalkanoates, polyesteramides, polyalkylene carbonate, polycaprolactone. Polyesters based on aliphatic hydroxycarboxylic acids, in particular polylactic acid and polycaprolactone and polyhydroxyalkanoates are mentioned. Preferred components in the polymer mixtures or as pure components are polylactic acid (PLA), polybutylene succinates, polybutylene succinate-co-adipates and polyhydroxyalkanoates, and in particular polyhydroxybutyrate (PHB) and polyhydroxybutyrate co-hydroxyvalerate (PHBV) and polyhydroxybutyrate-co-hydroxyhexanoate (PHBH In a preferred embodiment, an aliphatic polyester is used in admixture with polylactic acid. Preference is given to a mixture consisting of:

From 5 to 50% by weight of polybutylene adipate terephthalate (PBAT), polybutylene sebacate terephthalate (PBSeT) polybutylene succinate (PBS), polybutylene succinate dibasite (PBSA) and / or polybutylene succinate sebacate (PBSSe) and

50 to 95 wt .-% polylactic acid used. According to a particularly preferred embodiment, polybutylene adipate terephthalate is used in admixture with polylactic acid.

Particularly preferred is a mixture consisting of

5 to 50% by weight of polybutylene adipate terephthalate (PBAT)

50 to 95 wt .-% polylactic acid and

0 to 5% by weight of polybutylene succinate (PBS) and / or polybutylene succinate adipate

(PBSA)

used. Polylactic acid with the following property profile is preferably used:

a melt volume rate (MVR at 190 ° C and 2.16 kg according to ISO 1 133 of 0.5 - preferably 2 - 30 especially 20 ml / 10 minutes

a melting point below 240 ° C;

a glass transition point (Tg) greater than 55 ° C

a water content of less than 1000 ppm

a residual monomer content (lactide) of less than 0.3%.

a molecular weight greater than 80,000 daltons.

Preferred polylactic acids are, for example, NatureWorks® 6201 D, 6202 D, 6251 D, 3051 D and in particular 3251 D, 4032 D, 4043 D or 4044 D (polylactic acid from NatureWorks). Biodegradable polyhydroxyalkanoates are understood as meaning primarily poly-4-hydroxybutyrates and poly-3-hydroxybutyrates, and also include copolyesters of the abovementioned hydroxybutyrates with 3-hydroxyvalerates (P (3HB) -co-P (3HV)) or 3-hydroxyhexanoate. Poly-3-hydroxybutyrate-co-4-hydroxybutyrate (P (3HB) -co-P (4HB)) are known in particular from Metabolix. They are sold under the trade name Mirel®. Poly-3-hydroxybutyrate-co-3-hydroxyhexanoates (P (3HB) -co-P (3HH)) are known from the company P & G or Kaneka. Poly-3-hydroxybutyrates are sold, for example, by PHB Industrial under the brand name Biocycle® and by Tianan under the name Enmat®. The polyhydroxyalkanoates generally have a molecular weight M _{w of} from 100,000 to 1,000,000, and preferably from 300,000 to 600,000.

Polycaprolactone is marketed for example by the company. Daicel under the product names PLAC cel ^®.

Preferred polyester mixtures of partially aromatic polyesters and polylactic acid or polyhydroxyalkanoates are described in EP 1656 423, EP 1838784, WO 2005/063886, WO 2006/057353, WO 2006/057354, WO 2010/034710 and WO 2010/034712.

Among biodegradable polyalkylene carbonates are primarily polyethylene encarbonate (see EP-A 1264860), obtainable by copolymerization of ethylene oxide and carbon dioxide and in particular polypropylene carbonate (see, for example, WO

2007/125039), obtainable by copolymerization of propylene oxide and carbon dioxide.

The polyalkylene carbonate chain may contain both ether and carbonate groups. The proportion of carbonate groups in the polymer depends on the reaction conditions. conditions, in particular the catalyst used. In the preferred polyalkylene carbonates, more than 85 and preferably more than 90% of all linkages are cabonate groups. Suitable zinc and cobalt catalysts are described in US 4789727 and US 7304172. Polypropylene carbonate can also be prepared analogously to Soga et al., Polymer Journal, 1981, 13, 407-10. The polymer is also commercially available and is marketed, for example, by Empower Materials Inc. or Aldrich.

When working up the polyalkylene carbonates, it is particularly important to remove the catalyst as quantitatively as possible. For this purpose, the reaction mixture is usually diluted with a polar aprotic solvent such as a carboxylic acid ester (especially ethyl acetate), a ketone (especially acetone), an ether (especially tetrahydrofuran) to 2 to 10 times the volume. Subsequently, it is mixed with an acid such as acetic acid and / or an acid anhydride such as acetic anhydride and stirred for several hours at a slightly elevated temperature. The organic phase is washed and separated. The solvent is preferably distilled off in vacuo and the residue is dried.

The molecular weight Mn of the polypyrene carbonates produced by the abovementioned processes is generally from 70,000 to 90,000 Da. The molecular weight Mw is usually 250,000 to 400,000 Da. The ratio of ether to carbonate groups in the polymer is 5: 100 to 90: 100. To improve the application properties, it may be advantageous to treat the polyalkylene carbonates with MSA (maleic anhydride), acetic anhydride, di- or polyisocyanates, di- or polyoxazoline line or oxazines or di- or polyepoxides. Polypropylene carbonates having a molecular weight Mn of from 30,000 to 5,000,000, preferably from 35,000 to 250,000 and more preferably from 40,000 to 150,000 Da can be prepared in this way. Polypropylene carbonates with a Mn of less than 25,000 Da have a low glass transition temperature of less than 25 ° C. They are therefore only of limited suitability for surface applications (eg coating) with the pigments mentioned. The polydispersity (ratio of weight average (Mw) to number average (Mn)) is generally between 1 and 80, and preferably between 2 and 10. The polypropylene carbonates used may contain up to 1% carbamate and urea groups. Particularly suitable chain extenders for the polyalkylene carbonates are MSA (maleic anhydride), acetic anhydride, di- or polyisocyanates, di- or polyoxazolines or -oxazines or di- or polyepoxides. Examples of isocyanates are tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, naphthylene-1,5-diisocyanate or xylylene diisocyanate and in particular 1,6-hexamethylene diisocyanate, isophorone diisocyanate or methylene bis (4-isocyanatocyclohexane). Particularly preferred aliphatic diisocyanates are isophorone diisocyanate and in particular in particular 1,6-hexamethylene diisocyanate. As bisoxazolines are 2,2'-bis (2-oxazoline), bis (2-oxazolinyl) methane, 1, 2-bis (2-oxazolinyl) ethane, 1, 3-bis (2-oxazolinyl) propane or 1, 4 Bis (2-oxazolinyl) butane, especially 1, 4-bis (2-oxazolinyl) benzene, 1, 2-bis (2-oxazolinyl) benzene or 1, 3-bis (2-oxazolinyl) benzene. The chain extenders are preferably used in amounts of 0.01 to 5, preferably 0.05 to 2, particularly preferably 0.08 to 1 wt .-%, based on the amount of polymer.

Further, it is possible to add additives to the biodegradable polyester and / or polyalkylene carbonate. Additives are the typical in plastics technology; Nucleating agents such as e.g. Polybutylene terephthalate (PBT) in copolyesters of PBT (e.g., PBAT, PBSeT, PBST), polybutylene succinate in polylactic acid; Lubricants and release agents such as stearates (especially zinc, tin, and calcium stearate); Plasticizers such as citric acid esters (especially tributyl citrate and acetyl tributyl citrate), glyceric acid esters such as triacetylglycerol or ethylene glycol derivatives; Surfactants such as polysorbates, palmitates or laurates; Waxes such as carauba wax, candelilla wax, beeswax or beeswax ester, jojoba oil, Japan wax, spermaceti, wool wax; UV absorbers (for example hydroquinones); UV stabilizers; Anti-fog agents (e.g., polysorbates) or dyes. The additives are used in concentrations of 0 to 5 wt .-%, in particular 0.1 to 2 wt .-% based on the biodegradable polyester, and / or the polyalkylene carbonate. Plasticizers may be contained in 0.1 to 30% by weight (preferably 0.1 to 10% by weight) based on the biodegradable polyester, and / or polyalkylene carbonate.

Production of the fiber

The fibers used in the invention can be, for example, by a

Melt-spinning process (Franz Fourne, "Synthetic fibers" Carl Hanser Verlag, 1995, p 271 ff) .The polymer (the respective polyester or polyalkylene carbonate or the compound (the polymer mixtures mentioned above) is melted in a single-screw extruder with a smooth, grooved or grooved bush and The melt is cleaned after the discharge zone (metering zone) with a melt filter.The polymer melt is forced through one or more nozzles, cooled in a blow-hole and then wound on the winder after the preparation application.When using only one nozzle of mostly larger diameter The result is a so-called monofilament, in the case of several nozzles a multifilament, typical are multifilaments from 12 to 200 even up to> 200 monofilaments - hereafter called "thread." The nozzles have a diameter of typically 200 to 500 μm The monofilaments and multifilaments (threads) become treated with a preparation which t typically contains mineral oils or vegetable oils as lubricants dispersed in water. The preparation serves to avoid surface damage due to friction on the thread guides, which at the high running speeds of

1000 to 6000 m / min can occur. It is applied to the thread as a rod or pin preparation: over a defined slot or hole in a keratin. The preparation is continuously conveyed by a gear pump and wets the fiber surfaces.

The thread is drawn off with a driven delivery roller and then stabilized by several godets that regulate the thread tension via speed differences. Via speed differences and Galettentemperierung also takes a drawing of the thread in the ratio 1: 1, 1 to 1: 2. Subsequently, the thread is wound with a high-performance winder on bobbins.

A stable melt spinning process requires a corresponding flow behavior of the melted polymer / compound. The polymers used are generally predominantly of a linear structure and may only be present in a certain molecular weight range, which in polymer production is usually represented by the MVR (melt volume rate) according to IS01 133. There are polymers with an MVR of 5 to 50 ml / 10 min, preferably 12 to 35 ml / 10 min. more preferably 15 to 30 ml / 10 min. processed at the respective melt temperature. As a rule, a residual moisture <800 ppm, preferably <500 ppm, particularly preferably <200 ppm, is to be observed in order to minimize hydrolysis during processing.

By winding after exiting the die, the fiber is stretched, with the polymer chains being partially oriented in the fiber direction. When the polymer solidifies on cooling, amorphous and crystalline subregions are formed in the fiber. The ratio of amorphous and crystalline regions and the crystal structures formed depend strongly on the polymer and the withdrawal speed. As the take-off speed increases (typically in the range of 1000-6000 m / min), the orientation of the polymer chains improves. Without reforwarding one reaches LOY (low oriented yarn) and with appropriate godet guidance also POY (partially oriented yarn). HOY (high oriented yarn) is achieved only by post-stretching (Franz Fourne, "Synthetic fibers" Carl Hanser Verlag, 1995, p 417-459). It is also possible both a single polymer as several polymers in a filament in a defined geometry simultaneously Spiders to mix, usually with a so-called bicomponent melt spinning process.

The fibers are either combined into cables according to (Franz Fourne, "Synthetic fibers" Carl Hanser Verlag, 1995, S 460 to 489) and cut with fiber-cutting machines such as Gru-Gru or Lummus Cuttern or the Neumag fiber cutting edge The heat dissipation during the cutting process determines the usability of the systems without welding the polymers.

In this connection, particular mention must be made of additives which bring about nucleation of the fiber polymers which inhibit the known orientation-induced crystallization. reinforced by polymers. 0.05 to 10%, preferably 0.05 to 0.2% inorganic fillers such as calcium carbonate (PCC), talc, kaolin, mica. In addition, in PLA, for example, zinc phenylphosphonate, ethylene-bis-stearylamide, PBS, nucleating.

In PLLA with an L-lactic acid content of more than 99%, pure PDLA also nucleates in small amounts (1 to 10%).

Further additives may be added to the polymers and compounds for fiber production: dyes, such as titanium dioxide, iron oxides, and organic dyes, preferably in amounts of from 0.1 to 10% by weight, based on the polymer / compound,

Lubricants, such as fatty acid esters and fatty acid amides, preferably in amounts of from 0.01 to 5% by weight, based on the polymer / compound,

Plasticizers and dispersants such as triacetin, alkyl acetates, trialkyl citrates, alkanols and alkyl lactates, preferably in amounts of from 0.5 to 20% by weight, based on the polymer / compound, and flavorings such as linalol, geraniol and citral, preferably in amounts of 0.1 to 5 wt .-% based on the polymer / compound.

The polyester fiber and / or Polyakylencarbonatfasern can be used according to the invention for the production of all paper grades, e.g. Newspaper printing, SC paper (supercalendered paper), wood-free or wood-containing writing and printing papers and coated paper grades. For the production of such papers, for example, the main raw material components are groundwood, thermomechanical (TMP), chemo-thermomechanical (CTMP), pressure ground (PGW),

Bleached chemo-thermo-mechanical substance (BCTMP) as well as sulphite and sulphate pulp and waste paper.

The biodegradable polyester fibers and / or polyalkylene carbonate fibers used according to the invention can be used both as a solid and as a suspension in the papermaking process. The aqueous suspensions of the polyester fibers and / or polyalkylene carbonate fibers are diluted to such an extent that they are readily flowable. Sufficient fluidity is usually achieved at 0.05 to 20% by weight aqueous suspension of the biodegradable polyester fibers and / or polyalkylene carbonate fibers. The amount of biodegradable polyester fibers and / or polyalkylene carbonate fibers, based on the total material (dry), which is fed to the headbox of the paper machine, is from 0.3 to 40% by weight, in particular from 0.5 to 20% by weight. The addition according to the invention of the biodegradable polyester fibers and / or polyalkylene carbonate fibers is effected by metering to the pulp at a pulp concentration in the range from 5 to 100 g / l. In a pulp concentration of 20 to 100 g / l (corresponds to a pulp concentration of 2 to 10 wt .-% based on the aqueous pulp) is usually understood in the papermaking the thick stock. This is distinguished from the thin material, which is to be understood below as a fiber concentration in the range of 3 to 15 g / l. Subsequently, the total paper stock is diluted with water to a pulp concentration in the range of 5 to 15 g / l. A partial or complete dosage of the biodegradable polyester fibers and / or polyalkylene carbonate fibers only in the thin material is possible. However, the dosage in the thick matter is preferred.

The fibers or, preferably, their aqueous suspensions are admixed with the cellulose pulp or a mixture of cellulose pulp and filler in the papermaking operation so as to form the total pulp. In addition to the fillers and fibers, the overall fabric may contain other conventional paper additives. Conventional paper additives are, for example, sizing agents, wet strength agents, cationic or anionic retention aids based on synthetic polymers as well as dual systems, dehydrating agents, other dry strength agents, inorganic pigments (fillers), optical brighteners, defoamers, biocides and paper dyes. These conventional paper additives can be used in the usual amounts.

Suitable inorganic pigments (fillers) are all pigments customarily used in the paper industry on the basis of metal oxides, silicates and / or carbonates, in particular of pigments from the group consisting of calcium carbonate, in the form of ground (GCC) lime, chalk, marble or Precipitated calcium carbonate (PCC) can be used, talc, kaolin, bentonite, satin white, calcium sulfate, barium sulfate and titanium dioxide. It is also possible to use mixtures of two or more pigments. Usually, inorganic pigments having an average particle size (Z-average) .gtoreq.10 μm, preferably from 0.1 to 5 μm, in particular from 0.1 to 4 μm, are used. The determination of the average particle size (Z-average) of the inorganic pigments and of the particles of the powder composition is carried out in the context of this document generally by the method of quasi-elastic light scattering (DIN-ISO 13320-1), for example, with a Mastersizer 2000 from Malvern Instruments Ltd. ,

The sizing agents are alkylketene dimers (AKD), alkenylsuccinic anhydrides (A-SA) and rosin size.

Examples of retention agents are anionic microparticles (colloidal silicic acid, bentonite), anionic polyacrylamides, cationic polyacrylamides, cationic polyacrylamides and cationic polyacrylamides. starch, cationic polyethylenimine or cationic polyvinylamine in question. In addition, any combination thereof is conceivable, for example, dual systems consisting of a cationic polymer with an anionic microparticle or an anionic polymer with a cationic microparticle. In order to achieve a high filler retention, it is recommended to add retention aids of this kind, which can be added to the thick material, for example, but also to the thin material.

Dry strength agents are to be understood as meaning synthetic dry strength agents such as polyvinylamine or natural dry strength agents such as starch.

Following the formation of the sheet, the paper sheet passes through the press section. Here the leaf is further drained. The dry content of the moist paper web is increased with the pressure exerted in the press nip. The printing can be varied over a relatively wide range in many paper machines. After the press section, the dryer section follows. Here the drying takes place, in which a connection between paper fiber and polymer develops. Preference is given to a method in which the paper sheet is treated in the press section at temperatures in the range of 45 to 120 ° C (cylinder temperature).

The inventive method is used to produce filler-containing paper, filler-containing cardboard and filled cardboard. The respective filler content of paper, cardboard and paperboard can be from 3 to 50% by weight, based on the paper, cardboard or paperboard.

According to the process of the invention, filler-containing papers such as graphic papers, packaging papers and sanitary papers containing recycled fibers can be produced. In a preferred embodiment, a method of making graphic paper is preferred. The graphic papers include papers such as wood-free papers, wood-free writing and printing papers, wood-containing writing and printing papers, and wood-free and wood-containing base papers. Their filler content is usually 10 to 40 wt .-% based on the paper.

According to a further preferred embodiment, a process for the production of paper is preferred whose filler content is 10 to 20 wt .-%. Such papers are used primarily as packaging papers. According to a further preferred embodiment, a process for the production of paper is preferred whose filler content is 5 to 25 wt .-%. Such papers are used primarily for newspaper printing. According to another preferred embodiment, preference is given to a process for producing paper whose filler content is from 25 to 50% by weight, for example SC papers.

The process according to the invention makes it possible to produce filler-containing paper products having a reduced basis weight and the same strength. The biodegradable polyester fibers and / or polyalkylene carbonate fibers used in a process for producing paper and paper products according to the invention make it possible to produce paper with a higher filler content. As a rule, the loss of strength due to the higher filler content is significantly lower in comparison to known processes of the prior art. The papers obtained according to the invention have improved strengths and an increased breaking strength. As a result, a good printability (improved linting and dusting) is possible with the same or improved efficiency of the paper machine.

Furthermore, the method has energy savings in the drying process.

The invention will be explained in more detail by means of the following non-limiting examples.

Examples

1.) Analysis method

The molecular weights M _n and M _{w of} the partially aromatic polyesters were determined as follows:

15 mg of the partially aromatic polyesters were dissolved in 10 ml of hexafluoroisopropanol (HFIP). Each 125 μΙ of this solution was analyzed by gel permeation chromatography (GPC). The measurements were carried out at room temperature. For elution, HFIP + 0.05 wt% trifluoroacetic acid Ka salt was used. The elution rate was 0.5 ml / min. Shodex HFIP ^® 800P (diameter 8 mm length, 5 cm), Shodex ^® HFIP-803 (diameter 8 mm,: The following combination of columns (Showa Denko Ltd., Japan all columns manufactured by Fa.) Was used

Length 30 cm), Shodex ^® HFIP-803 (diameter 8 mm, length 30 cm). The partly aromatic polyesters were detected by means of an RI detector (differential refractometry). The calibration was carried out with narrowly distributed polymethyl methacrylate standards with molecular weights of M _n = 505 to M _n = 2,740,000. Elution areas outside this interval were determined by extrapolation. The determination of the viscosity numbers was carried out according to DIN 53728 Part 3, January 3, 1985, capillary viscometry. A micro Ubbelohde type M-II was used. The solvent used was the mixture: phenol / dichlorobenzene in a weight ratio of 50/50.

The determination of the melt volume flow rate (MVR) was carried out according to EN ISO 1 133. The test conditions were 190 ° C, 2.16 kg. The melting time was 4 minutes. The MVR indicates the rate of extrusion of a molten plastic molded article through an extrusion tool of fixed length and fixed diameter under the conditions described above: temperature, load and position of the piston. The volume extruded in a specified time in the cylinder of an extrusion plastometer is determined.

Used biodegradable polymers:

2.) Preparation of biodegradable polymer fibers

The experiments were carried out with the sale of products Ecovio ^® FS Paper A1500 (BASF SE) and Bionolle® 1020th

Ecovio FS Paper A1500 has an MVR (190 ° C, 2.16 kg) of 23 ml / 10 min. and a residual moisture of 190 ppm determined with a Brabender Aquatrac Plus. Ecovio FS Paper A1500 contains the aliphatic polyester polylactic acid with a melting point of 168 ° C and the aliphatic-aromatic polyester Ecoflex ^® with a melting point of 1 10 ° C. The residual moisture of Ecovio FS Paper A1500 is 600 ppm and the MVR (190 ° C, 2.16 kg) is 23 ml / 10 min.

Bionolle 1020 has an MVR (190 ° C, 2.16 kg) of 20 ml / 10 min. and a residual moisture of 380 ppm. The material is a polybutylene succinate from Showa Highpolymer, Japan. Construction of the pilot plant:

The pilot plant consisted of an extruder with 30 mm screw diameter. The screw length was 30 D. The extruder was tempered only in the feed zone at 190 ° C. The remaining 3 heating zones of the extruder and the other heating zones of screen changer with 2 sieves with 40 μηη mesh size to the spinning pump were set to the desired melt temperature. Since the extruder was operated in the lower power range, heating of the melt due to dissipation was not detected. The spinning pump with a specific delivery volume of 4.0

cm ³ / turn was operated at a rate of about 22 g / min. The nozzle package with a diameter of 1 15 mm consisted of 26 nozzles with a diameter of 300 μηη. It was heated to the desired melt temperature. The injection shaft had a length of about 1 m. The air freshener was used in the middle rich regulated with approx. 1 m / s. The preparation was conveyed by a gear pump and applied via a hole in a yarn guide on the 26 filaments. The multifilament was drawn off via an unheated delivery roller and then stabilized over 3 godet pairs. The godet pairs were unheated and had a speed difference of 10 m / min, which was controlled by microprocessor system. The multifilament was fed via a Karamikfadenführer without preparation addition to the automatic winder (Barmag), with a winding speed of 2500 m / min. was operated. The multifilaments were pinned to skeins with a twine, wetted with cold water and fed wet to a guillotine knife. By moistening the strands overheating of the fall blade was avoided when cutting. The short fiber samples were made in a length of 5 mm and then dried at 40 ° C for 8 h.

Example F1: Fiber production with Ecovio FS Paper C1500

The fibers of Ecovio FS Paper C1500 were produced at a melt temperature of 210 ° C at 22.5 g / min. and a spinning pressure of 40 bar. The result was a multifilament with a diameter of the individual filaments of 18.5 μηη at a titer of 3.35 dtex. The fiber strengths are determined using a tensile tester Zwick Z005 Zwisck / Roell GmbH according to ISO 2062 tensile test. With a modulus of elasticity of 3650 MPa, an elongation at break of 43% and a strength of 16.8 cN / tex were measured.

Example F2: Fiber production with Bionolle 1020

The fibers of Bionolle 1020 were produced at a melt temperature of 200 ° C at 22.5 g / min. and a spinning pressure of 33 bar. The result was a multifilament with a diameter of the individual filaments of 19.4 μηη at a titer of 3.71 dtex. The fiber strengths are determined using a tensile tester Zwick Z005 Zwisck / Roell GmbH according to ISO 2062 tensile test. At a modulus of elasticity of 940 MPa, an elongation at break of 193% and a strength of 16.3 cN / tex were measured.

The synthetic fibers were whipped at a concentration of 1 to 6% in water in the laboratory disintegrator for about 15 minutes so that individual fibers were present at the end.

Preparation of pulp suspension (pulp)

The respective fiber combination and drinking water were pitched free of specks at a solids concentration of 4% in the laboratory pulper. (In the case of pulp, the The mixture was additionally ground to a freeness of 30-35 SR.) The pH of the substances was in the range between 7 and 8. The ground substance was then diluted with drinking water to a solids concentration of 0.5% (5 g / l pulp concentration).

Examples 1 a, b, c

A pulp of bleached pulp (100% eucalyptus pulp) was added proportionally (without, 1 wt.%, 3 wt .-%) with the Ecovio FS paper fibers and calcium carbonate described in Example F1. From this, a sheet was formed which has a basis weight of 80 g / m ² and a filler content of 23% by weight.

The paper sheets were each produced on a Rapid-Köthen sheet former according to ISO 5269/2 with a sheet weight of 80 g / m ² . The drying was carried out at 90 ° C, while the leaves were dried between two filter papers for 7 min. Then it was calendered with a line pressure of 300 N / cm.

The pH of the paper stock suspension stock was in the range between 7 and 8. For the sheet formation, a cationic polyacrylamide (Percol ^® 540) was added to the dry paper pulp in an amount of 0.02 wt .-%. Example 2a, b, c

A paper stock from deinked wastepaper was proportionately added (without, 1 wt.%, 3 wt.%) To the Ecovio FS paper fibers and calcium carbonate described in Example F1. From this, a sheet was formed having a basis weight of 40 gsm and a filler content of 18 weight percent.

The paper sheets were each produced on a Rapid-Köthen sheet former according to ISO 5269/2 with a sheet weight of 40 g / m ² . The drying was carried out at 90 ° C, while the leaves were dried between two filter papers for 7 min. Then it was calendered with a line pressure of 300 N / cm.

The pH of the paper stock suspension was in the range between 7 and 8. For sheet formation, a cationic polyacrylamide (Percol 540) in amounts of 0.02 wt .-% based on the dry paper pulp was added.

Example 3a, b, c

A paper stock made from deinked waste paper and groundwood was mixed (without, 1% strength by weight, 3% strength by weight) with the Ecovio FS paper fibers and calcium carbonate described in Example F1. From this, a sheet was formed having a basis weight of 65 g / m ² and a filler content of 14 Gewichsprozent.

The paper sheets were each made on a Rapid-Köthen sheet former according to ISO 5269/2 with a sheet weight of 65g / m2. The drying took place at 90 ° C, while the leaves were dried between two filter papers for 7 minutes. Thereafter, calendering was performed with a line pressure of 300 N / cm.

Examination of the paper sheets of Example 1 a, b, c, 2a, b, c and 3a, b, c

After a storage time in a climate chamber at a constant 23 ° C and 50% humidity for 12 hours, the dry breaking length of the sheets were determined according to DIN 54540 and the internal strength (Scott Bond) according to DIN 54516. The measurements were calendered and not calendered. The calendering conditions were a line pressure of 300 N / cm and 80 ° C. The results are summarized in Table 1.

Sheetl

The results show that increasing the proportion of Ecovio FS Paper fibers increases the stability of the paper as both dry tear lengths and the Scott Bond value increase.

Example 4

In this example, fibers of Example F2 (Bionolle 1020) based on PBS (polybutylene succinate) were used and a packaging material model was used.

In this case, a paper stock made of 100% recovered paper was proportionally mixed with polyester fibers (Table 2).

From this, a sheet was formed analogously to Example 2, which has a basis weight of 75 g / m ² and a filler content of 13 percent by weight. The paper sheets were each produced on a Rapid-Köthen sheet former according to ISO 5269/2 with a sheet weight of 75 g / m ² . The drying was carried out at 90 ° C, while the leaves were dried between two filter papers for 7 min. In this example no further calendering took place.

The pH of the paper stock suspension was in the range between 7 and 8. For sheet formation, a cationic polyacrylamide (Percol 540) in an amount of 0.03% by weight, based on dry paper pulp, was added. Testing the paper sheets of Example 4

After a storage time in a climate chamber at a constant 23 ° C and 50% humidity for 12 hours, the dry breaking length of the sheets were tested according to DIN 54540, the bursting pressure according to DIN 2759 and the flat crushing resistance according to DIN 53143.

The results are summarized in Table 2.

Table 2: Application results of the cardboard of Example 4

The results show that with a higher content of polybutylene succinate fibers, carton stability increases as both flat crush resistance, bursting pressure and dry breaking length increase.

U.S. Provisonal Application No. No. 61 / 565,518, filed 1/1/201 1, is incorporated by reference in the present application.

Claims

claims

Process for the production of filler-containing paper, cardboard and paperboard comprising dewatering a paper stock with sheet formation and drying, characterized in that biodegradable polyester fibers and / or polyalkylene carbonate fibers are added to the paper stock.

A method according to claim 1, characterized in that as biodegradable polyester fibers and / or polyalkylene carbonate fibers having a weight of 0.1 to 100 dtex, are used.

A method according to claim 1 or 2, characterized in that one uses as biodegradable polyester fibers and / or Polyalkylencarbonatfasern fiber with lengths of 0.5 to 20 mm.

A method according to claim 1 or 3, characterized in that the biodegradable polyester fibers and / or polyalkylene carbonate consist of one or more water-insoluble biodegradable polyester and / or polyalkylene carbonate.

Method according to one of claims 1 to 4, characterized in that the biodegradable polyester fibers of one or more polyesters based on aliphatic and aromatic dicarboxylic acids with aliphatic dihydroxy compounds or aliphatic dicarboxylic acids with aliphatic dihydroxy or aliphatic hydroxycarboxylic acids.

Method according to one of claims 1 to 5, characterized in that one or more polyester fibers are added, which are an aliphatic or aliphatic-aromatic polyester.

Process according to any one of Claims 1 to 6, characterized in that one or more polyester fibers are added comprising an aliphatic polyester selected from polybutylene succinate (PBS), polybutylene sucocyanadipate (PBSA), polybutylene succinate sebacate (PBSSe) and polybutylene sebacate (PBSe ) are.

8. The method according to any one of claims 1 to 7, characterized in that biodegradable polyalkylene carbonate fibers are used, which consist of polypropylencarbonat.

9. The method according to any one of claims 1 to 8, characterized in that the biodegradable polyester fibers of a mixture consisting of

5 to 50% by weight of polybutylene adipate terephthalate (PBAT), polybutylene sebacate terephthalate (PBSeT) polybutylene succinate (PBS), polybutylene succinate adipate (PBSA) and / or polybutylene succinate sebacate (PBSSe) and

50 to 95% by weight of polylactic acid

are.

10. The method according to any one of claims 1 to 9, characterized in that one doses 0.3 to 40 wt .-%, biodegradable polyester fibers and / or polyalkylene lencarbonatfasern based on the dry paper.

1 1. Method according to one of claims 1 to 10, characterized in that one produces the paper, the cardboard or the cardboard with a filler content of 3 to 50 wt .-%.

12. The method according to any one of claims 1 to 1 1, characterized in that graphic papers are produced.

13. The method according to any one of claims 1 to 1 1, characterized in that packaging papers are produced.