Precipitated Calcium Carbonate Filler Research Articles

Study of Preparation and the Influencing Factors of Chrysanthemum-Shaped Calcium Carbonate Applied to Paper Industry

This paper describes the precipitated calcium carbonate filler applied to paper industry, which was prepared by adding a specific crystal control agent. And a series of influencing factors in carbonation process was studied, such as carbonization temperature, concentration of milk of lime, carbon dioxide concentration and the crystal shape control dosage. Therefore the optimum conditions for preparation of chrysanthemum-shaped crystalline calcium carbonate were determined.

Starch-sodium stearate complex modified PCC filler and its application in papermaking

The use of fillers tends to reduce paper strength, which can limit their application. Therefore research on filler modification is of significant importance in order to overcome this limitation. In this paper, precipitated calcium carbonate (PCC) was modified by starch, sodium stearate, and the starch cross-linking agent sodium hexametaphosphate. The purpose of this research is to provide useful references to the industrial application of modified precipitated calcium carbonate (PCC). Modified precipitated calcium carbonate (PCC) was characterized by particle size analyzer and scanning electron microscope (SEM). The analysis showed that the particle size of the modified PCC was significantly increased versus the control. The morphology of modified PCC also greatly changed. The influence of modified and unmodified PCC filled paper on paper physical performance was studied. The experimental results showed that at the same ash content, modified PCC filled paper compared with unmodified PCC filled paper had higher brightness, lower opacity, and higher physical strength. The impact of modified and unmodified PCC on stock retention and the comparison between modified and unmodified PCC were investigated. The experimental results showed that the stock filled with modified PCC had better retention compared to those filled with unmodified PCC.

Effect of particle size of magnesium silicate filler on physical properties of paper

AbstractFillers are essential component of printing papers to increase the opacity, brightness, and to improve formation and printing properties. As a very little work has been reported so far on magnesium silicate (talc), the study was conducted with the filler of different particle size for papermaking. The sheets were made in the laboratory with refined mixed hardwood chemical pulp with five grades of talc, ground calcium carbonate (GCC) and precipitated calcium carbonate (PCC) fillers with 15–24% ash level. Apparent density along with tensile, burst, tear index, Z‐direction tensile strength (ZDTS) and bending stiffness index were evaluated for talc filled sheets, and compared with GCC and PCC. Physical strength properties of talc filled sheets were decreased at a faster rate on increasing filler loading in paper and decreasing the particle size of the filler. With same type of filler its particle size determines the physical properties of paper. The postulate was not found to be valid for all the three varieties of fillers viz., talc, PCC and GCC. Shape and geometry of the PCC and GCC fillers determine the individual property. © 2012 Canadian Society for Chemical Engineering

Performance of bamboo plastic composites with hybrid bamboo and precipitated calcium carbonate fillers

AbstractThe influences of hybrid bamboo and precipitated calcium carbonate (PCC) fillers in a recycled polypropylene/polyethylene matrix on the properties of bamboo plastic composites were studied. Thermogravimetric and Fourier transform infrared analyses of both thermo‐mechanically refined bamboo fiber (RBF) and ground bamboo particle (GBP) showed relatively higher holocellulose content in RBF, and more effective silane grafting on the RBF surface. The raw PCC particles contained over 95% calcium carbonate, and had an agglomerated form consisting of particles with a mean diameter of about 1.2 microns. Compounding the PCC particles with the plastic resin helped separate and disperse them in the matrix. Measured flexural strength and modulus of PCC‐only‐filled composites increased significantly from 15 to 30% PCC content levels, while the tensile and impact strength of composites decreased with the addition of PCC. For composites with hybrid bamboo and PCC fillers, tensile and flexural moduli were improved with the increase of PCC content. After silane treatment, RBF‐filled composites showed noticeably increased mechanical properties compared with those of GBP‐filled composites. For modulus values, PCC–bamboo–polymer composites were 3–4 times higher than those of PCC–polymer composites at high PCC levels. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers

Pre-flocculation of precipitated calcium carbonate filler by cationic starch for highly filled mechanical grade paper

Three commercial starches were evaluated in conjunction with colloidal silica and flocculant to retain precipitated calcium carbonate (PCC) filler. A unique feature of this study was the fact that the filler was pre-flocculated by a portion of starch (2kg starch/t PCC) and the rest of the starch was added after the flocculant but before the silica. The pulp used was peroxide bleached thermo-mechanical pulp (TMP). A statistical design methodology was employed and empirical process models were constructed based on the analysis of variance (ANOVA) results. The models were then employed to predict the retention and drainage. It was found that the high-charged cationic starch gave the highest retention and best drainage performance. The high-charged cationic starch S880 also resulted in stronger paper, probably because of the larger and stronger flocs produced and its higher affinity with the fiber and fines. Finally, pre-flocculation was found to provide stronger paper compared with a conventional starch/retention aid addition sequence.

Addition of precipitated calcium carbonate filler to thermoplastic polyurethane adhesives

Precipitated calcium carbonate filler (PCC) was added to a thermoplastic polyurethane adhesive (TPU). The addition of PCC produced a moderate increase in the rheological and viscoelastic properties of TPU due to the poor dispersion of filler (i.e. found to be clusters) and the weak interactions between the PCC nanoparticles and the polymer chains. The interactions were noticed by ATR-IR spectroscopy by displacement of the bands at 3326, 1729 and 1061 cm −1 to higher wave number of the polyurethane. Furthermore, the first glass transition temperature of the polyurethane was found to decrease by adding PCC filler. The crystallinity of the soft segments in the TPU was decreased by adding PCC because of the disruption of the degree of phase separation in the polymer. The initial adhesive strength in PVC/TPU adhesive/PVC joints increased noticeably by adding PCC filler, the greater the amount of filler in the TPU, the greater the initial adhesive strength found. Finally, the highest final adhesive strength (72 h after joint formation) was obtained in the joint produced with the TPU containing 10 wt% PCC.

Comparative Properties of Thermoplastic Polyurethane Adhesive Filled with Natural or Precipitated Calcium Carbonate

AbstractSummary: The rheological, mechanical and adhesion properties of thermoplastic polyurethane adhesive (TPU) containing natural ultramicronized or precipitated nanometric calcium carbonate filler were compared. Precipitated calcium carbonate addition did not noticeably improve the rheological properties of filled TPU with respect to the effect produced by adding natural calcium carbonate. The precipitated calcium carbonate nanoparticles migrated to the TPU surface due to incompatibility between the filler and the polyurethane. The wettability of the filled TPU was reduced by adding natural calcium carbonate, but it was increased slightly by adding precipitated calcium carbonate. Finally, the immediate adhesive strength in PVC/TPU adhesive/PVC joints increased noticeably when the adhesive contained filler; however, the final adhesive strength was similar irrespective of the filler particle size.

Optimization of chemical use for highly filled mechanical grade papers with precipitated calcium carbonate

Response surface methodology was used with four factors to screen for the best starch and optimize the use of chemicals in order to maximize precipitated calcium carbonate (PCC) filler retention in a peroxide-bleached TMP suspension. Three commercial starches were used in conjunction with colloidal silica and flocculant. The PCC loading level and the interactions between PCC level, starch, flocculant, and silica were investigated, and empirical models were constructed. The empirical process models were then employed to predict the retention and drainage. It was found that medium-charged cationic starch (S858) gave the highest total and filler retention, whereas high-charged cationic starch (S880) resulted in the best drainage. The ash content of the handsheet can be pushed up to 40% using the retention system with medium (S858) and high (S880) charged cationic starch. The high-charged cationic starch (S880) gave stronger paper, probably because of its higher affinity with the fiber and fines.

Carboxymethyl cellulose/alum modified precipitated calcium carbonate fillers: Preparation and their use in papermaking

Abstract Carboxymethyl cellulose and alum were used in the modification of precipitated calcium carbonate filler, and the use of modified fillers in papermaking was investigated. The alum dosage was found to be much critical to the effective precipitation and encapsulation of carboxymethyl cellulose on filler surfaces. When the dosages of carboxymethyl cellulose and alum were 4% and 12% (based on the dry weight of precipitated calcium carbonate), respectively, filler modification significantly improved filler retention by as much as 71.5%, and the brightness and opacity of the filled paper were strikingly enhanced; however, paper strength was practically unchanged, indicating improved affinity of filler particles to fibers in the aqueous papermaking wet end system. XPS analysis and SEM observations of the fillers confirmed the surface encapsulating effect of the modifiers on the filler. SEM images of the paper-sheets indicated that modified filler particles were more effectively adhered and bonded to the pulp fibers, in comparison to unmodified filler particles.

Retention of PCC and GCC fillers on chemical pulp fines surfaces

We studied the retention of precipitated and ground calcium carbonate fillers (PCC and GCC, respectively) on chemical pulp fines surfaces by measuring the amounts of adsorbed fillers on the surfaces of the primary and secondary fines and long fiber fractions of eucalyptus pulp in the presence of a polymeric flocculant (CPAM). The mechanism of filler particle retention and adsorption on fines surfaces was clarified in more detail by measuring the kinetics of PCC adsorption in the absence of flocculant. The results showed that the primary and secondary fines fractions adsorb more PCC and GCC fillers on their surfaces (per gram of pulp) than the long fiber frac-tion in both the absence and presence of flocculants. In the absence of flocculants the adsorption of PCC both on fines and on the fiber fractions follows Langmuir kinetics, implying that the adsorption is in dynamic equilibrium with filler detachment and the maximum possible amount of filler that can be adsorbed corresponds to the monolayer coverage of particles. At low flocculant doses, i.e., doses that are relevant to papermaking, the fines fractions adsorb significantly more filler than the fiber fractions. In this case, their high surface charge density promotes CPAM adsorption onto fines, which in turn increases the adsorption of fillers to the fines surfaces through polymer bridges.

Modification of precipitated calcium carbonate filler using sodium silicate/zinc chloride based modifiers to improve acid-resistance and use of the modified filler in papermaking

In order to improve the acid-resistant property of papermaking grade precipitated calcium carbonate filler and to obtain modified filler in powder form, sodium silicate/zinc chloride based modifiers were used in filler modification, and the use of modified filler in papermaking of deinked pulp derived from recycled newspaper was also preliminarily investigated. Under the preliminarily optimized experimental conditions, when sodium silicate, zinc chloride, sodium hexametaphosphate, and phosphoric acid with dosages of 10 wt%, 3 wt%, 1 wt% and 0.2 wt%, respectively, were used as modifiers, and when the temperature, aging time, and PCC concentration during the filler modification process was 70 oC, 7 h and 9.1 wt%, respectively, the acid-resistant property of filler was significantly improved after modification, as evaluated using alum consumption and pH methods. The use of modified precipitated calcium carbonate filler prepared under the optimized conditions provided considerably more brightness and light scattering improvement in comparison to unmodified filler, and filler modification was found to have only negligible influence on tensile and burst strength of the paper, air permeability of the paper, and retention performance of the filler. Surface analysis of the modified filler using XPS and SEM confirmed the occurring of surface encapsulation and modification of precipitated calcium carbonate filler when the relevant modifiers were used in filler modification. The encapsulating effect of modifiers on filler was thought to be favorable to improvement in acid-resistant property, and optical properties of the filled paper.

A preliminary investigation into the use of acid-tolerant precipitated calcium carbonate fillers in papermaking of deinked pulp derived from recycled newspaper

The use of acid-tolerant precipitated calcium carbonate fillers, including phosphoric acid/sodium hexametaphosphate modified precipitated CaCO3 filler, and sodium silicate/phosphoric acid/sodium hexametaphos-phate modified precipitated CaCO3 filler in papermaking of deinked pulp derived from recycled newspaper was explored. These two acid-tolerant fillers provided considerably more brightness improvement in papers in comparison the unmodified filler, presumably indicating alleviated pulp darkening achieved as a result of better acid-resistant properties. The addition of acid-tolerant fillers into the furnish slurries gave lower system pH as compared with unmodified filler. Among the three fillers used in this work, the effect on retention of modification of the filler with sodium silicate/phosphoric acid/sodium hexametaphosphate was probably the best, as evaluated from ash content measurements. For air permeability of the paper, the use of acid-tolerant fillers provided slightly more improvement in comparison to the unmodified filler. For tensile and burst strength of the paper, the use of sodium silicate/phosphoric acid/sodium hexameta-phosphate modified precipitated calcium carbonate filler gave better results as compared with the other two fillers. Additionally, the improving effect of acid-tolerant fillers on furnish static drainage was found to be slightly weaker than that of unmodified filler.

The anomalous effect of high intensity ultrasound on paper fibre‐filler combinations

PurposeThe purpose of this paper is to explore the previously unreported phenomenon in which changes occur to the particle size distributions of calcium carbonate fillers, used in papermaking, when exposed to high intensity ultrasound.Design/methodology/approachCommercial paper pulps sonicated at a frequency of 20 kHz are found to produce aggregates of their mineral filler constituents. The effects of sonication on isolated long and short fibre, and ground and precipitated calcium carbonate filler systems are also investigated both with and without the presence of dispersants. The findings are supported by particle size analysis and scanning electron microscopy of the sonicated systems.FindingsIt is clearly shown that exposure to high intensity ultrasound induces filler aggregation. However, the effect only occurs when paper fibres and fillers coexist and is not apparent for suspensions of filler only or fibre only slurries. Furthermore, the treatment overrides the effect of dispersants used to keep filler in suspension during the manufacturing process. An accompanying fall in pH with increasing sonication times is also noted and is linked to these changes. It is proposed that radical species produced in the slurries during sonication may explain the observed phenomenon.Research limitations/implicationsThe role of pH is not clearly understood and needs further study.Practical implicationsThe findings may be of interest in paper manufacture where uniform dispersal of fillers throughout the pulp is of significant importance.Originality/valueThe phenomenon described in this paper has not previously been reported or explored. Further studies may add to knowledge of filler dispersions and their behaviour in papermaking.

Flocculation kinetics of precipitated calcium carbonate

When the percentage of filler in paper is increased, the optical properties are improved and the production cost lowered. However, fillers weaken paper strength by decreasing the fibre–fibre bonded area. Little is known about the optimum filler floc size or filler floc properties to allow developing optimum paper characteristics. Consequently, the kinetics of aggregation of scalenohedral precipitated calcium carbonate (PCC) filler was studied using various polymers (flocculants, coagulants and dry strength agents). The sodium salt of partially hydrolysed polyvinyl formamide copolymerized with acrylic acid (PVFA/NaAA) or C-starch lead to floc sizes, less sensitive to dosage within a certain range. Results from stability ratios correlate with PCC particle size. The change in particle size measured by photometric dispersion analysis (PDA) correlates well with the change in PCC particle size measured by light scattering/diffraction. Kinetic calculations show the orthokinetic aggregation times to be consistent with the experimental PDA results. The main uncertainty in the orthokinetic times is estimating the effective shear rate. It is proposed that the bridging surface area of PCC particles, the area which can form bonds between PCC particles or aggregates, should be used to study the kinetics of PCC aggregation, and not the total or projected surface area. In polymer induced aggregation, the PCC particle size increases to a plateau value with increasing polymer dosage. Two regions are most pronounced for C-PAM, PVFA/NaAA and A-starch. Region I corresponds to bridging flocculation. Region II is where the particle size reaches a plateau, and not the expected maximum predicted by classical polymer bridging theory or charge neutralisation theory, likely because of a competition between particle aggregation and polymer adsorption.

Synthesis of Needle-Like Aragonite Crystals in the Presence of Magnesium Chloride and Their Application in Papermaking

PCC (precipitated calcium carbonate) and ground calcium carbonate have been widely used in alkaline papermaking. Unfortunately, although increasing filler level in papers can improve the paper properties such as brightness, opacity, stiffness gloss, smoothness, porosity, and printability, as well as decrease cost, some strength of the paper is negatively affected. In this research, needle-like aragonite was synthesized using Ca(OH)2 and CO2 as reactants in the presence of MgCl2 and characterized with scanning electronic microscopy (SEM) and X-ray diffraction (XRD). The physical and optical properties of the paper handsheets containing these needle-like aragonite fillers were evaluated. Results indicated that tensile strength, Z-direction tensile strength and folding endurance of the paper were improved by the needle-like aragonite crystals compared to the paper using commercial PCC (precipitated calcium carbonate) as filler. The stiffness of the paper handsheet on the machine direction was increased, but no evident difference in the cross direction was found. The improvement of paper strength mainly resulted from the twining effect between the aragonite whiskers and paper fibers. The optical properties of the paper were slightly decreased with the use of the needle-like aragonites compared to commercial PCC. These results suggest that paper cost can be decreased by increasing the content of needle-like aragonite filler while paper strength will not be decreased compared to PCC filler.

Preparation and application of cationized pulp fiber as a papermaking wet-end additive

Cationized pulp fibers (CPF) were prepared by the adsorption of a novel biodegradable cationic ester quaternary ammonium salt (31441) on bleached softwood kraft pulp fibers. The optimized conditions for the CPF preparation were: 4% of 31441 (based on oven-dry pulp), 80°C and 30 min. The CPF was characterized by FT-IR, SEM and XPS. Experimental results showed that the CPF improved the retention of precipitated calcium carbonate (PCC) filler significantly. With 0.9% CPF (based on oven-dry pulp), the retention of PCC increased from 57.53% to 72.21%. The physical properties of paper were also slightly improved. The tensile strength and burst strength of the paper with CPF were higher than those with CPAM. CPF addition had no effect on the stock drainage.

Flocculation of PCC filler in papermaking: Influence of the particle characteristics

The influence of precipitated calcium carbonate (PCC) characteristics on the flocculation process and flocs structure was investigated in the presence of a linear, high molecular weight, cationic polyacrylamide of high charge density. For that, a commercial PCC sample was used, either as supplied (original PCC) or after a washing process (treated PCC). The PCC samples were characterised, and the flocculation process, for different flocculant concentrations, was monitored using the light diffraction scattering technique (LDS). Flocs structure was evaluated by determining the mass fractal dimension of the flocs. It was found that the particle size of the original PCC was larger than that of the PCC submitted to the cleaning process. As a consequence, the optimum flocculant dosage was lower for the original PCC than for the treated PCC. Despite the kinetics of flocculation being independent of the differences in the PCC samples, the flocs compactness at the end of flocculation was higher in the case of the original PCC, resulting in more resistant flocs to shearing. The results showed that the PCC characteristics affect mainly the optimum flocculant dosage, the flocs structure and, thus, the flocs resistance and their reflocculation capability.

Interactions between polymers and precipitated calcium carbonate filler

Interactions between polymers and precipitated calcium carbonate filler

The Performance of Precipitated Calcium Carbonate Fillers in Fine Quality Printing and Writing Papers

ABSTRACTThe trend toward alkaline papermaking has accelerated over the past four years due to the availability of inexpensive, high quality precipitated calcium carbonate. This movement has been largely brought about through on-site production of precipitated calcium carbonate (PCC). Over ten facilities exist in North America providing the host mills with custom-made PCC products to provide specific properties for the paper grades being manufactured.Laboratory studies were recently conducted to investigate the performance of paper-grade PCC fillers in fine quality printing papers. This investigation focused on the effect of changes in PCC particle size, size distribution, surface area, and morphology on paper properties. The PCC fillers were also compared to other filler materials such as ground limestone and kaolin.In general, the results show that sheet properties are greatly influenced by the size and shape of the PCC product used. The data reveal strong correlations between average particle size and/or surface area, and sheet properties such as opacity, porosity, tensile strength, bulk, and sizing within certain filler morphologies.

End Group Effects in Polymer Modification of Calcium Carbonate Fillers

Abstract Two types of polymer, e.g., polybutadiene and poly(oxy-2-butenyleneoxyfumaroyl), having four different end groups, were prepared and used to treat ground and precipitated calcium carbonate fillers. The coupling effects of the polymer modifiers were evaluated from the physical properties of the filler-loaded vulcanizates of sulfur-cured SBR and peroxide-cured EPDM. The phosphate-terminated polymer was found to be an excellent surface modifier of the ground calcium carbonate filler. For the precipitated calcium carbonate filler of superfine grade, higher coupling effects were attained by the phosphates having relatively small alkyl groups. The modification mechanism is also discussed by taking into account the results of infrared spectroscopy, x-ray analysis, gel permeation chromatography, scanning electron micrography, and BET analysis.