DE102009014957A1 - Hydrophobic modified cellulose fibers for cementitious self-leveling compounds and screeds - Google Patents

Abstract

Stabilizing and viscosifying agents based on hydrophobic, fluid-containing cellulose-containing fiber improve the processing and the product properties of self-leveling cementitious compounds and self-leveling compounds. For this purpose, it is necessary that the cellulosic fiber contains superplasticizers such as melamine or polycarboxylate polymers, as well as water repellents such as alkyl ketene dimer or alkyl succinic anhydride. By adjusting the fiber length, fiber diameter, degree of loading and by the type and amount of the hydrophobizing agent and the flow agent segregation of the cement paste and the formation of microcracks are prevented. In the case of screed and quick-setting cement, the newly developed fiber compounds generally do not need to increase the water-cement factor. Cement hardening is more uniform, sedimentation, sanding and bowls are largely prevented. The preparation, properties and characterization of the cellulosic stabilizers and viscosifiers as well as applications are described.

Description

Technical status

Self-leveling compounds and self-leveling screeds are required in addition to superplasticizers (Superplasticizers) other additives for a perfect workmanship. Typical for cementitious screed masses are two or three filler fractions (usually more spherical Quartz sand and the like), which have a high degree of filling, high density and a ensure sufficient slump. For flowing screed the cement weight is preferably 200 to 450 kg, in individual cases up to 550 kg the water-cement ratio is preferably low - mostly below 0.70, occasionally below 0.45.

Are common in the industry additions like dispersion powder for the remuneration of the cement, wetting agent, defoamer and more recently also stabilizers and viscosifiers. The commercial products offered for stabilization are mostly pre-reacted prepolymers, such as longer-chain melamine sulfonates or copolymers. These products are aimed at modifying the flow agent especially as they are compatible with this and soluble in this should be. Also the electrostatic mechanisms for flow regulation are often the same as the superplasticizer. Another approach goes in the direction of viscosity reduction existing thickener such. Carrageenan from algae - these Products have not yet been on the flow screed market enforced. A modification of the self-leveling masses by means of a cellulosic fiber structure is not yet known.

• 1. Segregation und Sedimentation des Füllstoffs
• 2. Bluten des Zementleimes (Abtrennung von Anmachwasser)
• 3. Mikrorisse
• 4. Volumenschwund und Schusseln
• 5. Absanden
• 6. Rauhe Oberflächen und Versprödung

The cellulose-containing fiber compound according to the invention is surprisingly able to significantly improve the processability of a large number of self-leveling construction products (screed, quick-setting cement, cement base, self-leveling compounds). The cellulose fiber can - depending on the fiber length - contribute to the stability and to the regulation of the water balance. For self-leveling building products, however, a hydrophobic cellulose is required, which does not change the water-cement factor. The flow agents for adjusting the cement slump are generally used in an amount of 0.5 to 3.0 wt .-%. These superplasticizers often cause additional problems in dosage, processing and also in the final product, for example

• 1. Segregation and sedimentation of the filler
• 2. Bleeding of the cement paste (separation of mixing water)
• 3. micro cracks
• 4. Volume shrinkage and bowls
• 5. Absands
• 6. Rough surfaces and embrittlement

• a) Hydrophobie. Zur Einstellung der wasserabweisenden Eigenschaften wird bevorzugt Alkylketendimer AKD, ein Alkyl- oder Alkylen-Bernsteinsäurederivate ASA oder Polymer Sizing Agent PSA verwendet, weiterhin Alaune und Fettsäurederivate.
• b) Superplastifizierung. Zur Einstellung der superplastifizierenden Eigenschaften bei FE wird die Faser mit einem Fließmitteln gecoatet, co-processed, gemischt oder beaufschlagt. Der Superplastifizierer kann z. B. Melamin oder Polycarboxylat sein.

The cellulose-containing stabilizing and viscosifying agent according to the invention was prepared on the basis of various cellulose-containing raw materials, characterized and tested in typical applications, such as liquid screed and thin-layer rapid cement. For this purpose, it is necessary to modify the cellulose fiber so that the component can be further processed for the production of a stabilizer and viscosifier:

• a) hydrophobicity. To adjust the water-repellent properties it is preferred to use alkyl ketene dimer AKD, an alkyl- or alkylene-succinic acid derivative ASA or polymer sizing agent PSA, furthermore alum and fatty acid derivatives.
• b) Superplastication. To adjust the superplasticizing properties of FE, the fiber is coated, co-processed, blended, or loaded with a flow agent. The Superplastifizierer can z. As melamine or polycarboxylate.

For this a manufacturing technology was created, which required the product quality (hydrophobic functionalized cellulose fiber) can; the processing can be continuous or discontinuous respectively. The preferred types of cement for self-leveling compounds are Portland cement (in particular CEM I 32 5 R), composite cement (CEM II), blast furnace slag cement (CEM III) or calcium aluminate cement (TSZ), always with a sufficient amount of suitable filler and the required superplasticizer.

embodiments

Production of a cellulose fiber AKD polycarboxylate compound. It was preferably a cellulose fiber with a fiber length of 5 microns 300 microns in the presence of 2.0-9.0 wt .-% Alkylketendimer AKD with chain length C 16-18 at 15-115 ° C coated. At the same time or subsequently, the product with 0.1-8.0 wt .-% liquid coated according to polycarboxylate. There is obtained a crude white hydrophobic cellulose fiber with a weight of 160-172 g / L and 93% dry matter, which has about 1-22% sieve residue to 100 microns (air jet screening). The fiber is suitable for the stabilization of self-leveling compounds and self-leveling screeds.

cement-based Self-leveling compounds and flow marks contain cement, spherical quartz filler (mostly two sieve fractions), Superplastifizier based on polycarboxylate or melamine, stabilizing agent such as hydrophobic, Superplasticizer-containing cellulose fiber and other additives like dispersion powder and defoamer.

• – hydrophob und verträglich mit allen marktüblichen Fließmitteln
• – Wasser-Zement-Faktor muss in der Regel nicht angepasst werden
• – verhindert Bluten, Segregation, Absanden sowie Mikrorisse
• – ermöglicht eine homogene Zementhärtung.

Richtrezeptur: Komponente Funktion Formulierung Gewichts-% Zement, bevorzugt CEM I 32,5 R Bindemittel 33,50 Hydrophobe Cellulose mit Superplastifizierer Stabilisierung 0,25 (0,10–0,50 ) Superplastifizierer wie Polycarboxylat oder Melamin Fließmittel 0,70 (0,50–1,50) Dispersionspulver Bindemittel 1,20 Quarzsand sphärisch 0.5–1.2 mm Estrich Füllstoff grob 41,10 Quarzsand sphärisch 0.1–0.3 mm Estrich Füllstoff fein 23,20 Silicon-Emulsion Entschäumer Zusatz bei Bedarf Stearatsalz Hydrophobierung Zusatz bei Bedarf Summe 99,6–101,0 Wasserbedarf ca. 600 ml/kg Mörtel* *abhängig vom eingesetzten Füllstoff, Fließmittel und DispersionspulverA hydrophobic cellulose does not fulfill the self-running properties in the cement. A cellulose fiber, which is only equipped with plasticizer, additionally requires mixing water, whereby the cement strength is deteriorated. By contrast, the combination product cellulose with hydrophobing and flow agent meets the requirements; The product is a new stabilizer and viscosifier for self-leveling soil leveling compounds, flow screeds, grouting mortars, repair mortars and thin-layer quick cements:

• - hydrophobic and compatible with all commercially available superplasticizers
• - Water-cement factor does not usually need to be adjusted
• - prevents bleeding, segregation, sanding and microcracks
• - enables homogeneous cement hardening.

Starting formulation: component function formulation % by weight Cement, preferably CEM I 32.5 R binder 33.50 Hydrophobic cellulose with superplasticizer stabilization 0.25 (0.10-0.50) Superplasticizers such as polycarboxylate or melamine superplasticizer 0.70 (0.50-1.50) dispersion powder binder 1.20 Quartz sand spherical 0.5-1.2 mm Coarse filler coarse 41.10 Quartz sand spherical 0.1-0.3 mm Screed filler fine 23.20 Silicone emulsion defoamers Addition on demand stearate waterproofing Addition on demand total 99.6 to 101.0 water requirements about 600 ml / kg mortar * * depending on the filler used, the flux and the dispersion powder

1) examination of the cellulose fiber AKD polycarboxylate compound in the cementitious screed, polycarboxylate modified.

It was 0.25% by weight of hydrophobic cellulose fiber compound according to the invention together with 33.25% by weight of cement CEM I 32 5 R, 41.40% by weight coarse Quartz sand 0.5-1 2 mm, 23.20 wt .-% fine quartz sand 0.1-0.3 mm, 0.70 wt .-% polycarboxylate "Woerment FM 787 (BASF) and 1.20% by weight of dispersion powder in liquid screed used, with a maximum of 5 cm layer thickness. The screed has water-cement factor w / z 0.479, a sufficient slump size 42 to 49 cm and becomes floating laid. To determine the exact w / z factor is the flow agent in half given the required mixing water, then more Anmach is water dosed until the processing viscosity is reached.

segregation of cement paste and the formation of microcracks is at 3-5 cm layer thickness largely prevented. The screed mass is processable for about 30 minutes, the open time is unchanged from the 0 pattern or slight extended. The Shore A hardness is after 8 hours at 20 ° C and 80% r. F. About 74 (walk-in) and after 24 hours about 88.

2) exam of the cellulose fiber AKD polycarboxylate compound in the cementitious screed, melamine-modified.

It was 0.25% by weight of hydrophobic cellulose fiber compound according to the invention together with 33.25% by weight of cement CEM I 32 5 R, 41.40% by weight coarse Quartz sand 0.5-1.2 mm, 23.20% by weight of fine quartz sand 0.1-0.3 mm, 0.70% by weight of melamine "Melment F 217 G "(BASF) and 1.20 wt .-% of dispersion powder used in liquid screed, at maximum 5 cm layer thickness The screed has water cement factor w / z 0.485, a sufficient Slump 39 up to 47 cm and is laid floating. Segregation of the cement paste and the formation of microcracks is largely at 3-5 cm layer thickness prevented. The screed mass is processable for about 20 minutes, the open time is unchanged or slightly longer than the 0 pattern. The Shore A hardness is after 16 hours at 20 ° C and 80% RH about 73 (walkable) and after 32 hours about 86.

3) exam of the cellulose fiber AKD polycarboxylate compound in the thin layer Quick cement.

It was 0.25% by weight of hydrophobic cellulose fiber compound according to the invention together with 39.50 wt.% cement CEM I 32 5 R, 55.65 wt.% screed fine filler 0.08 to 1.4 mm, 1.10 wt .-% polycarboxylate Woerment FM 787 (BASF) and 3.50 % By weight of dispersion powder used in rapid cement, at maximum 0.9 cm layer thickness. The quick cement contains aluminate for acceleration and is after 4 hours at 20 ° C and 80% r. F. Dust-dry and crack-free cured.

Claims (16)

Multifunctional additive based on a cellulose-containing Fiber, hydrophobicizing and superplasticizing (liquefying) Contains additives, preferred for Construction products such as cement-based Self-leveling compounds, flow marks and quick cements. An additive according to claim 1, wherein for adjusting the superplasticizing Properties the fiber coated with a plasticizer, co-processed, For example, the superplasticizer may be mixed or charged Melamine resin, melamine sulfonate, polycarboxylate or a suitable one Copolymer, which is the electrostatic interaction of the particles in cement paste. An additive according to claim 1, wherein for adjusting the hydrophobic Features the fiber coated with a water repellent, co-processed, mixed or applied. Additive according to claim 3, wherein for adjusting the water-repellent Properties preferred alkyl ketene dimer AKD, an alkyl or alkylene succinic acid derivatives ASA or Polymer Sizing Agent PSA is used to continue alum and fatty acid derivatives. An additive according to claim 1, wherein fiber length, fiber diameter, degree of loading and the type and amount of the hydrophobizing agent and the flow agent an insert for Allow construction products. An additive according to claim 1, wherein the fiber length of the cellulose is at maximum 4000 μm is, but preferably at 5-500 microns, the degree of loading at 0-99 Wt .-% but preferably 1-50 Wt .-%. An additive according to claim 3, wherein instead of a hydrophobicized Cellulose is a silicone paper fiber, a release paper fiber, an oil paper fiber or the like is used. An additive according to claim 1, wherein instead of a hydrophobicized Cellulose pulp, (B) CTMP, ATMP, deinking paper, waste paper, Paper sludge, Annual plants or the like is used. An additive according to claim 1, wherein the fiber has viscosity, flow behavior, Plasticity, Rheopexy and yield point of dry mortar after addition of water and in ready-to-use cementitious systems controls. An additive according to claim 1, wherein soluble components such as cellulose ethers, starch, Guar hydrolysates, welan gum, gellan, curdlan, carrageenan, polycarboxylic acids or Polyvinyl alcohols are included as a mixture. An additive according to claim 1, wherein the dry blend comprises powdered polysaccharides such as rhamsan, dextran, pullulan, biopolymer S-657, curdlan and derivatives thereof, marine thickeners (such as alginates, agar, Car rageen or derivatives), phytochemicals (such as locust bean, gum arabic, karaya, tragacanth, ghatti), plant seeds (such as guar, okra, psyllium, mesquite or derivatives) and optionally also cellulose fiber, microcrystalline cellulose, polyurethanes, polyacrylates, polyethers or polyacrylamide are. An additive according to claim 1, wherein the additive is primarily by means of thermo-mechanical process is produced, wherein another Pre-treatment of raw materials by chemicals, radiation, ultrasound, enzymes, or the like is not excluded. An additive according to claim 1, wherein for controlling the rheology, stability and processing other components such as dispersants, biocides, Cement additives such as alkanolamine or polyethyleneamine, adjusting agents like bentonite or smectite, wetting agent, defoamer, antifreeze like Glycol, antioxidants, anti-rust additives such as polyphosphonates, Gluconates or the like are included. An additive according to claim 1 which is capable of uniform curing and improved early strength as well as improved mechanical values (compressive strength, flexural modulus) to ensure. An additive according to claim 1 which is capable of forming a thick layer Order in one operation to ensure smooth surfaces without flow problems to ensure, to extend the open time, the formation of microcracks during to prevent the drying phase and the Antiabsetzwirkung ready to use To control systems. An additive according to claim 1, which has the mechanical properties of cementitious end products like screed and thin coating (such as abrasion values, strength, notched impact strength and the like) constant stops or improves.