WO2003093578A1

WO2003093578A1 - A filter composition, a process of making the composition and the use of the same

Info

Publication number: WO2003093578A1
Application number: PCT/CN2003/000308
Authority: WO
Inventors: Kim Kiu Jacky Chim; Zhilun Yuan
Original assignee: Addata Development Limited
Priority date: 2002-04-30
Filing date: 2003-04-28
Publication date: 2003-11-13
Also published as: AU2003236169A1; CN1455044A; CN1268810C

Abstract

The present Invention discloses a filler composition, mainly comprised of 30-38 weight parts of Si02, 15-21 weight parts of CaO, 17-21 weight parts of MgO, 2-3 weight parts of A1203, 3.9-5.9 weight parts of S042- and 8.8-31 weight parts of crystal water. It may also contain Fe203, Na20 and K20 in amount of less than 1 % of the total weight parts of the composition. The composition is mainly made of (i) talc, (ii) natural calcium metasillicate, (iii) bentonite, (iv) magnesia or magnesium carbonate and (v) surfactant. The surfactant is mainly comprised of 10-12 weight parts of Si02, 7-11 weight parts of A1203, 36-39 weight parts of S042- and 27-38 weight parts of crystal water, It may also contain Fe203, CaO, Na20 and K20 in amount of less than 7.2 % of the total weight parts of the surfactant. Also, the present invention discloses a process of making the filler composition and the use of the same in the field of paper-making.

Description

Filler composition, preparation method and application thereof

Field of invention

The invention relates to a filler composition, a preparation method and application thereof, and in particular, to a filler composition for papermaking, a preparation method thereof and application in papermaking. technical background

The main raw material of papermaking is plant fibers. In the paper, the plant fibers are woven into a network structure, thereby giving the paper various properties. In the paper industry, in order to save the amount of plant fibers and improve certain properties of paper, various fillers are usually added to the paper, such as calcium carbonate, talc, and kaoline. International patent application WO 01/44573 discloses the preparation of paper products by adding at least one aluminum compound and at least one silicate to the pulp. US5300147 discloses a low brightness magnesium silicate SLR filler, a low brightness paper containing the filler, a preparation method of the filler and its application in papermaking.

On the other hand, the paper industry acknowledges that the filling of fillers is very limited. Excessive filling will cause serious deterioration of various technical indicators of the paper, especially mechanical strength (such as fracture length, tear strength, etc.). It will also affect the papermaking process index and printing performance index. Therefore, the actual filling amount is usually 20-35%, and some products (such as newsprint) are basically not filled. Summary of invention

An object of the present invention is to provide a filler composition, which can be added to paper with a relatively high loading amount and maintain a high actual retention rate of 75-85%, and at the same time, the indicators of the paper meet the relevant standards And optimize some indicators.

Another object of the present invention is to provide a method for preparing a filler composition.

Yet another object of the present invention is to provide the use of a filler composition.

The present invention provides a filler composition. The main chemical composition of the composition is as follows: 30-38 parts by weight of SiO ₂ , 15-21 parts by weight of CaO, 17-21 parts by weight of MgO, and 2-3 parts by weight of A1 ₂ Ο ₃ , 3.9-5.9 parts by weight of SO /-and 8.8-31 parts by weight of crystal water.

The filler composition of the present invention further contains Fe ₂ 0 ₃ , Na ₂ O, and K ₂ 0, and the total weight part thereof is less than 1% by weight of the entire composition.

The filler composition of the present invention is mainly composed of (i) talc, (ii) natural calcium metasilicate, (iii) bentonite, (iv) It is made from magnesium oxide or magnesium carbonate and (V) surfactant. The main chemical composition of the surfactant is as follows:

10-12 parts by weight of SiO ₂ , 7-11 parts by weight of A1 _{2 0} ₃ , 36-39 parts by weight of SO ₄ ^2- , and 27-38 parts by weight of crystal water. The chemical composition of the surfactant further includes Fe ₂ O ₃ , CaO, Na ₂ O, and K ₂ O, and the total weight part thereof is less than Ί1% of the weight part of the entire surfactant.

The filler composition of the present invention further comprises one or more raw materials selected from the group consisting of gypsum, zeolite, sodium aluminum sulfate, polyaluminum sulfate silicate, and magnesium silicate hydrate.

The filler composition of the present invention is a white powder with a whiteness of 85% and an average particle size of 5-10 microns, wherein the weight percentage of the fibrous particles is 36-60%, and the aspect ratio of the fibrous particles is 10 .

The invention also provides a method for preparing a filler composition, which method comprises the following steps: mixing raw material talc, natural calcium metasilicate, bentonite and magnesium oxide or magnesium carbonate, and pre-grinding into a fine particle powder;

Pre-grind the surfactant into a fine-grained powder, or mix the surfactant with optional one or more of gypsum, zeolite, sodium aluminum sulfate, polyaluminum sulfate silicate, and hydrated magnesium silicate. Pulverized into fine-grained powder;

The two kinds of fine-grained powders are mixed uniformly, and further ground to a particle size of 5-10 microns, the surfactant can be prepared as follows: sulfuric acid solution is added to aluminum hydroxide for acid hydrolysis, and sodium silicate and Optional calcium carbonate and / or sodium sulfate and / or potassium sulfate and / or cationic starch, stir well, cool to crystallize, and dry.

The invention also provides the application of the filler composition in papermaking.

The present invention also provides a paper product containing a filler composition, such as writing paper, offset book paper, and the like. The filler composition of the present invention can be added to the paper with a relatively high filling amount and maintain a high actual retention rate of 75-85%, while making the various indexes of the paper meet the relevant standards, and optimizing some indexes. The filler composition has a certain water purification effect, and still has higher water filtration performance under higher filling conditions; and helps to whiten and sizing; stable performance, suitable for long-term storage. The filler composition is suitable for various major paper grades (such as writing paper, printing paper, sole paper and specialty paper), and its application does not require major adjustments to existing papermaking equipment and processes. In addition, the filler composition of the present invention has low cost, can be reused, has no toxic and side effects, has a simple preparation method, and is easy to popularize and apply. BRIEF DESCRIPTION OF THE DRAWINGS

Figure la-le is a photomicrograph reflecting the structure of the filler composition of the present invention, Figure la shows the structure composed of talc, bentonite and calcium silicate; Figure lb shows the bentonite combines talc and calcium silicate into a network; lc shows that the newly-born sub-nanometer aluminum silicate and ettringite (also called wrought white, which has high whiteness and strong adsorption) are adsorbed on calcium silicate and talc flakes; Figure Id shows sub-nanometer aluminum silicate Adsorbed on talc and calcium silicate; Figure le shows the intercalation on talc, bentonite, and calcium silicate grades.

Figures 2a-2f are photomicrographs reflecting the composition and structure of the filler composition and paper fibers of the present invention, Figure 2a shows the interactive network structure formed by talc and natural calcium metasilicate and paper fibers, and Figure 2b shows natural metasilicic acid Calcium and talc are attached to the fiber; Figure 2c shows natural calcium metasilicate and talc (flaky) covered with fiber by bentonite; Figure 2d shows the new cationic starch silicic acid sol wrapped paper fibers, natural metasilicic acid Calcium and talc nets are suspended from paper fibers; Figure 2e shows that natural calcium metasilicate (acicular) and talc are networked by bentonite and filled between paper fibers; Figure 2f shows the transfer of paper fibers It is bonded by sub-nanometer bentonite and cationic starch silicic acid sol.

Fig. 3 is an X-ray diffraction pattern of the filler composition of the present invention.

Fig. 4 is an ash X-ray diffraction pattern of a paper containing a filler composition of the present invention. Detailed description of the invention

The main chemical composition of the filler composition of the present invention is expressed in the form of oxide as: 30-38 parts by weight of SiO ₂ , 15-21 parts by weight of CaO, 17-21 parts by weight of MgO, 2-3 parts by weight of A1 ₂ Ο ₃ , 3.9 -5.9 parts by weight of SO ₄ ² -and 8.8-31 parts by weight of crystal water; may further contain Fe ₂ O ₃ , Na ₂ O, and K ₂ O, the total weight of which is less than 1% by weight of the entire composition.

The raw materials of the filler composition of the present invention are mainly (i) talc, (ii) natural calcium metasilicate, (iii) bentonite, (iv) magnesium oxide or magnesium carbonate, and (V) a surfactant. Talc can be obtained, for example, from Wenchuan, Sichuan, and can also be purchased from the market, such as, but not limited to, Yingkou, Liaoning and Liuzhou, Guangxi. Natural calcium metasilicate can be obtained, for example, from Tengchong, Yunnan, Dadingshan, Jilin, Datuo, Jiangxi, etc., or can be purchased from the market. For example, Jilin Lishu Wollastonite Mining Company's product name is Dadingshan. , But not limited to this. Bentonite can be obtained, for example, from Sichuan Shuangliu, or can be purchased from the market, such as Sichuan Shuangliu Bentonite Plant and Guangdong Foshan Bentonite Plant, but it is not limited thereto. Magnesium oxide in the present invention refers to active magnesium oxide, which is light-burned magnesium oxide fired from magnesite (magnesium carbonate) at a low temperature of 600-700 ° C, and is generally mainly used for coatings, rubber, plastics, and papermaking fillers ( pigment). The magnesium oxide and magnesium carbonate can be produced, for example, in Dashiqiao, Liaoning Province, for example, products sold by Dashiqiao Non-metallic Company in Liaoning.

The main chemical composition of the surfactant is 10-12 parts by weight of SiO ₂ , 7-11 parts by weight of A1 _{2 0} ₃ , 36-39 parts by weight of SQ ₄ ² _, and 27-38 parts by weight of crystal water. The chemical composition of the surfactant also contains Fe ₂ O ₃ , CaO, Na ₂ O, and K ₂ O, and the total weight part thereof is less than 7.2% by weight of the entire surfactant. The filler composition of the present invention may also optionally include one or more raw materials selected from the group consisting of gypsum, zeolite, sodium aluminum sulfate, polyaluminum sulfate silicate, and hydrazone silicate.

In the filler composition of the present invention, talc is a flake crystal produced naturally, and because of its high whiteness and low hardness, it can be used to improve the smoothness and printability of paper products.

In the filler composition of the present invention, natural calcium metasilicate is a naturally-occurring fibrous aggregate. After ultrafine pulverization, the particle size is 5-10 microns, and the aspect ratio is 10. It has excellent slender fiber characteristics and can be partially Instead of short paper fiber. Traditional fillers are low-hardness materials (for example, talc, kaolin, etc. have a hardness of 1), but fillers with a hardness greater than 3 are rarely used. The hardness of the fibrous calcium metasilicate used in the present invention is 4.5-5. These calcium metasilicate particles are surface-activated under the action of a surfactant, so that the needle-shaped particles overlap each other. A large amount of colloidal particles (such as hydrated magnesium silicate, cationic starch, etc.) that are positively charged during hydrolysis are added to the filler composition, and the needle-like calcium metasilicate particles are wrapped layer by layer (as shown in Fig. 1). These particles are easy to align in parallel with the layer of paper due to the action of laminar water during papermaking, and form a smooth paper surface with the paper fibers. Therefore, the hardness of calcium metasilicate is a kind of functional filler.

In the filler composition of the present invention, bentonite is used as a surface coating material of talc, natural calcium metasilicate or magnesium carbonate, so that it forms a strong chemical bond with negatively charged wood fibers, and improves its retention and adhesion. It improves the wet strength and the uniformity of the composition dispersion when it is formed into paper, and forms a binder with a certain elasticity when it is dried and solidified, which firmly bonds the filler and the paper fibers to improve the strength of the paper product. In addition, bentonite can also be used as a good flocculant and decolorant.

In the filler composition of the present invention, magnesium oxide or magnesium carbonate is used as a dispersant and a retention aid for the filler. Organic polymer retention aids are commonly used in the prior art. Magnesium oxide or magnesium carbonate can help the filler composition to be uniformly dispersed in the paddle when the filler composition is used in papermaking, so that the filler composition is combined with the paper fibers and it is difficult to fall off the fibers. Even after secondary beating and re-papermaking, high retention and high uniformity can be maintained.

In the filler composition of the present invention, the surface active agent is used to modify and surface modify the raw materials used, and during the hydration process of the filler composition, it promotes the formation of various new silicate compounds. Surfactants can be prepared as follows: Add sulfuric acid solution to aluminum hydroxide, stir at 70-80 ° C for 1-2 hours for acid hydrolysis, and then add sodium silicate and optional calcium carbonate and / or sulfuric acid Sodium and / or potassium sulfate, stirred at 70-80 ° C for 30-60 minutes, cooled to crystallize and dried. When the surfactant is prepared, cationic starch can also be added to form nano- or sub-nano-scale cationic starch silicic acid sol, which can be used for papermaking to improve the tensile strength of paper products. The cationic starch content is 8-9.8% by weight of the surfactant.

The filler composition of the present invention is prepared by a mechanical mixing method. The original of the filler composition of the present invention The material can be divided into two parts. The first part is talc, natural calcium metasilicate, bentonite, and magnesium oxide or magnesium carbonate. The second part is surfactant, optional gypsum, zeolite, sodium aluminum sulfate, and polymeric sulfate silicic acid. Aluminum and hydrated magnesium silicate, the preparation method of the filler composition is to mix and grind the raw materials of the first part and the second part respectively, and then mix the two powders evenly and further grind to a particle size

5-10 microns.

The obtained filler composition is a white powder with a whiteness of 85% and an average particle size of 5-10 microns, wherein the weight percentage of the fibrous particles is 36-60%, and the aspect ratio of the fibrous particles (L / D ) 10.

Compared with the fillers of the prior art, the filler composition of the present invention has a different structure mechanism. The filler particles in the prior art are mostly flaky and granular, and it is difficult to form a reasonable pile. The filling form is mainly mechanical filling between paper fibers, and the structure is loose. Therefore, as the filling amount increases, the mechanical strength index of the obtained paper will decrease sharply. The main raw materials of the filler composition of the present invention are fibrous, needle-shaped, flake-shaped, and granular, and when they are hydrolyzed, the various raw materials constituting the product are firstly flake-shaped and granular particles that are interconnected with needle-shaped fibers as a skeleton. Form a reasonable structure (see Figure 1). After chemical bonding with the paper fibers, the network structure of the paper fibers and the filler composition network structure are embedded together to form a reasonable structure of the paper (see Figure 2). The filler composition of the present invention has the function of a structural material, and therefore, in the case of a relatively high filling, the mechanical strength is not greatly reduced.

The bonding mechanism of the filler composition of the present invention and paper fibers is also different from the fillers of the prior art. The combination of the prior art filler and paper fiber is a kind of physical adsorption, that is, natural filling and sizing and consolidation in the papermaking process, and its bonding strength is limited. The combination of the filler composition of the present invention with paper fibers is mainly a chemisorption, and its bonding strength is strong. The specific surface energy of the ultrafine powder of the present invention is very high, and the powder particles have a strong positive charge under the strong action of a surfactant during hydrolysis, and form a strong chemical bond with paper fibers with a strong negative charge Figures 1 and 2). Active molecules such as polymerized aluminum sulfate silicate, hydrated magnesium silicate, highly suspended sodium magnesium aluminosilicate sol, zeolite, and cationic starch silicate sol, which are formed after the filler composition is hydrolyzed, strongly adhere to powder and paper fibers. During the drying process of papermaking, it dehydrates and solidifies and produces sub-nanometer new minerals, so that the powder and the paper fiber are firmly bonded. The above-mentioned physical-chemical process enables the filler composition of the present invention to maintain a high "retention rate" and "wet strength" on the paper, and still maintain a high mechanical strength after the paper is formed.

The following examples further illustrate the present invention. Preparation of surfactant

Surfactant 1

42.9 g of a 60% by weight sulfuric acid solution was added to 13.9 g of aluminum hydroxide, and the mixture was stirred at about 80 ° C for 1.5 hours for acid hydrolysis, and then 15.4 g of sodium silicate was added, and stirred at about 80 ° C for 45 minutes. The crystals were cooled, dried at about 120 ° C, and then pulverized to obtain Surfactant 1.

The chemical composition of Surfactant 1 measured by the internationally used chemical total analysis method is: 10.1 parts by weight of SiO ₂ , 7.2 parts by weight of A1 ₂ Ο ₃ , 35.8 parts by weight of SO ₄ ^2- , 27.1 parts by weight of crystal water, and 0.30 parts by weight Fe ₂ O ₃ . Among them, Fe ₂ 0 ₃ is caused by impurities contained in the raw materials used. Surfactant 2

46.0 g of a 60% by weight sulfuric acid solution was added to 15.0 g of aluminum hydroxide, and the mixture was stirred at about 70 ° C for 1 hour for acid hydrolysis, and then 16.7 g of sodium silicate was added, and stirred at about 70 ° C for 60 minutes. The crystals were cooled, dried at about 100 ° C, and then pulverized to obtain Surfactant 2.

The chemical composition of Surfactant 2 measured by the internationally used chemical total analysis method is: 12.3 parts by weight of SiO ₂ , 10.9 parts by weight of A1 ₂ Ο ₃ , 39.1 parts by weight of SO ₄ ^2- , 38.2 parts by weight of crystal water, and 0.37 parts by weight Fe ₂ O ₃ . Among them, Fe ₂ 0 ₃ is caused by impurities contained in the raw materials used. Surfactant 3

39.9 g of a 60% by weight sulfuric acid solution was added to 12.9 g of aluminum hydroxide, and the mixture was stirred at about 75 ° C for 2 hours for acid hydrolysis, and then 14.0 g of sodium silicate, 1.5 g of calcium carbonate, and 13.8 g of sodium sulfate were added. And 4.4 g of potassium sulfate, 9.9 g of cationic starch and 1000 ml of water, stirred at about 75 F for 30 minutes, cooled and crystallized, dried at about 150 F, and then pulverized to obtain 111.0 g of a surfactant 3.

The chemical composition of Surfactant 3 measured by the internationally used chemical total analysis method is: 11.2 parts by weight of SiO ₂ , 8.6 parts by weight of A1 ₂ Ο ₃ , 37.4 parts by weight of SO ₄ ² , 33.4 parts by weight of crystal water, and 1.2 parts by weight of CaO , 3.7 parts by weight of Na ₂ O, 1.5 parts by weight of K ₂ O, and 0.35 parts by weight of Fe ₂ O ₃ . Preparation of filler composition

Example 1

Use a plastic mixer to mix raw materials 37 g of talc (purchased from Liaoning Yingkou Non-metallic Mine Company), 40 g of natural calcium metasilicate (purchased from Jilin Lishu Wollastonite Company, trade name Dadingshan), 11 g of bentonite (Purchased from Sichuan Shuangliu Bentonite Powder Factory), 6 g of magnesium oxide (purchased from Liaoning Dashiqiao Non-metal Company), pre-ground Into fine-grained powder; pre-mill 7 g of surfactant 2 into fine-grained powder with a CX 132 ultra-fine grinder; mix the two fine-grained powders uniformly with a plastic mixer, and further grind to an average particle size of 7 Microns.

The resulting composition was a white powder with a whiteness of 90%. The weight percentage content of the fibrous particles was measured by the internationally-used chemical total analysis method, and the aspect ratio of the fiber particles was 11 when measured by a Hitachi S-530 electron microscope. The chemical composition of the powder of the composition was measured by a general international chemical analysis method. As a result, it was 30.2 parts by weight of SiO ₂ , 15.2 parts by weight of CaO, 17.1 parts by weight of M _g O, 1.9 parts by weight of A1 _{2 0} ₃ , and 3.9 parts by weight of SO. ₄ ^2- , 8.9 parts by weight of crystal water and 0.5 parts by weight of Fe ₂ 0 ₃ . Example 2

Use a plastic mixer to mix 39 g of talc (purchased from Liaoning Yingkou Non-metallic Mine Company), 45 g of natural calcium metasilicate (purchased from Jilin Lishu Wollastonite Company, trade name is Dadingshan), 13 g of bentonite (Purchased from Sichuan Shuangliu Bentonite Powder Factory), 8 grams of magnesium oxide (purchased from Liaoning Dashiqiao Non-metals Co., Ltd.), pre-milled into fine-grained powder; 9 grams of surfactant 1 with a CX 132 superfine grinder 1 Pre-grind into fine-grained powder; mix the two kinds of fine-grained powder with a plastic mixer, and grind it to an average particle size of 5 microns.

The resulting composition was a white powder with a whiteness of 88%>. The weight percentage content of the fibrous particles was 52% measured by the international general chemical analysis method. The length-to-diameter ratio of the fiber particles was 11 measured by a Hitachi S-530 electron microscope. The chemical composition of the powder of the composition was measured by a universal chemical analysis method, and the results were 38.1 parts by weight of SiO ₂ , 21.0 parts by weight of CaO, 21.1 parts by weight of MgO, 3.1 parts by weight of A1 _{2 0} ₃ , and 5.9 parts by weight of SO ₄ ² -, 31.0 parts by weight of crystal water and 0.7 parts by weight of Fe ₂ O ₃ . Example 3

35 grams of talc (purchased from Liaoning Yingkou Non-metal Mine Company), 35 grams of natural calcium metasilicate (purchased from Jilin Lishu Wollastonite Company, trade name Dadingshan), 9 grams with a plastic mixer Bentonite (purchased from Sichuan Shuangliu Bentonite Powder Factory), 4 g of magnesium carbonate (purchased from Dashiqiao Non-metallic Company, Liaoning), pre-ground into fine-grained powder; 5 grams of surfactant 3 were mixed with a CX 132 ultra-fine grinder 3 It is pre-milled with 4.2 g of gypsum, 3.8 g of zeolite, 9.9 g of sodium aluminum sulfate, 4.8 g of polymeric aluminum sulfate silicate, 13.2 g of magnesium silicate hydrate, and a fine-grained powder; use a plastic mixer to mix the above two kinds of fine-grained powder Uniform and further ground to a particle size of 10 microns.

The resulting composition was a white powder with a whiteness of 85%. Use of internationally accepted chemical analysis methods It was measured that the weight percentage of the fibrous particles was 36%, and the aspect ratio of the fibrous particles was 10 when measured with a Hitachi S-530 type electron microscope. The chemical composition of the powder of the composition was measured by a general international chemical analysis method. As a result, it was 35.2 parts by weight of SiO ₂ , 18.2 parts by weight of CaO, 20.1 parts by weight of M _g O, 2.7 parts by weight of A1 _{2 0} ₃ , and 4.8 parts by weight of SO. ₄ ^2- , 25.1 parts by weight of crystal water, 0.4 parts by weight of Fe ₂ O ₃ , 0.56 parts by weight of Na ₂ O, and 0.07 parts by weight of K ₂ O. Papermaking and testing

The obtained filler composition was used for papermaking, and the obtained paper was tested.

The filler composition is first pulped when used in papermaking, that is, 4 times of clean water that meets the requirements of papermaking is added to the filler composition, heated to 50-60 ° F and stirred for 40 minutes, maintaining a ρΗ value of 6.5-7.5.

The conventional papermaking process is pulp pulping → pulping → dilution → papermaking, adding the filler composition slurry prepared above during pulping, and then manufacturing offset printing paper according to conventional papermaking technology, and measuring the main technical indicators of the obtained paper. Writing paper

The filler composition of Example 1 was used to make 55 g / m ² writing paper. The raw materials of the product were needle blades (15% by weight), broad blades (40% by weight), and filler composition (45% by weight). The resulting finished paper had an ash content of 29.1% and a retention rate of 76%. The test results of the obtained paper are shown in Table 1 below.

Test Item Unit Product Standard GB 12654-90

Class A

Basis weight g / m ² 50 ± 2.5 54.5 Whiteness% ^ 80 83.2 Opacity% ^ 75 87.4 Sizing degree mm ^ 0.75 0.75 Smoothness S ^ 25 53 Positive and negative surface difference% ^ 30 36.9 Folding resistance (transverse) times ^ 6 8 dust degree / m ² 80 28

0.3-1.5 wake up ²

Moisture% 6 ± 2.0 6.8 Ash content 29.1 Break length m-2400 Figures 3 and 4 show the X-ray diffraction patterns of the ash content of the filler composition of the present invention and the paper containing the composition, respectively. Agree. This indicates that the chemical composition and molecular structure of the filler composition of the present invention are well maintained during the papermaking process. Offset book paper

The filler composition of Example 2 was used to manufacture 70 g / m ² of offset book paper, and the raw materials of the products were imported Russian softwood pulp (25% by weight), Simao pine bleached pulp (35% by weight), and blue pressed pulp (10 Wt%) and filler composition (30 wt%). The test results of the obtained paper are shown in Table 2 below. Product inspection results

QB / T1211-1911 Class A

Basis weight g / m ² 70 ± 3.0 71 Split longitudinal m 4130 Broken transverse m 2560 Long average m ^ 3000 3345

Whiteness% 70-75 90 Tightness g / m ³ 0.85 0.80 Moisture% 4.0-8.0 5.96 Sizing degree mm 0.25 1.10 Folding resistance times ^ 5 13 Opacity% ^ 82 89 Dust degree / m ² 100 40

(0.3-2.0 mm ² )

Ash content 25.94 Tear index mn · m ² / g 5.90 Ash content of mixing tank ― 33.21 Water purification performance test

The filler composition of Example 3 was used to make 55 g / m ² writing paper, and the obtained paper was tested to obtain a test result similar to that of the filler composition of Example 1 described above. In addition, the water quality analysis of the papermaking water and the papermaking wastewater in the total discharge during the papermaking process showed that the papermaking process did not significantly affect the water quality, and most of the pollutant elements in the water (such as mercury, cadmium, arsenic, lead) , Nickel, phenol, cyanide, sulfide, formaldehyde, zinc, magnesium, etc.) did not increase, in addition, the total suspended matter, chromium, copper and calcium content decreased significantly.

In the process of filling the writing composition with the filler composition in Example 1 and filling the offset printing book with the filler composition in Example 2, the water quality analysis of the papermaking water and papermaking wastewater was also performed, and the results similar to the above table were obtained.

Therefore, the filler composition of the present invention exhibits good water purification function when used in papermaking. Traditional packing There is only a mechanical filtering effect on the papermaking water, so the water purification effect is weak. The filler composition of the present invention is an ultra-fine powder with colloidal characteristics. When the powder is hydrolyzed, under the strong action of a modifier (such as a surfactant), a new ultra-fine polymerized aluminum sulfate silicate and hydrated silicon are formed. Particles such as magnesium acid, highly active aluminum magnesium silicate sol, zeolite, and cationic starch silicate sol, strongly adsorb various heavy metal ions in water, such as copper, cadmium, mercury, arsenic, complex, lead and other harmful elements. Good purification, sterilization and antiseptic effect.

It was also found in the tests that the filler composition of the present invention has a better dewatering function. The traditional filler is relatively simple, so the geometric stacking is not reasonable. The filler is filled in the network structure of the paper fiber, which blocks the water filtering channel, and the water filtering effect is poor. The filler composition of the present invention is a composite filler composed of various raw materials. Needle-like, sheet-like, and granular materials form a reasonable pile when hydrolyzed (as shown in Figure 1), and combine with fibers to form a reasonable network structure of paper (see Figure 2). Therefore, even under higher filling conditions, there is still better water filtration and dehydration.

The filler composition of the present invention has high reusability, which helps to fully utilize and save resources. The traditional filler has a weak binding force with paper fiber, and the filler and the fiber quickly disengage during recycling, which is consumed in the pulping process. However, the paper filled with the filler composition of the present invention has a strong binding force between the filler and the paper fiber during the recycling process, so the recycling rate of the filler composition without the retention aid is 73%. The mechanism is as follows: Under the agitation of the aqueous medium and the mechanism, the modified silicate, which functions as a bond, is once again reduced to positively charged particle groups. After the filler composition is separated from the paper fibers, it still relies on its surface charge difference to maintain binding.

Papers filled with the filler composition of the present invention have significantly improved indicators such as whiteness, opacity, folding resistance, and ink absorption. The filler composition of the present invention has a high natural whiteness (usually not less than 85%), and the powder of the filler composition adheres to the paper surface by a surface potential difference, and produces a physical "bleaching" effect.

In addition, the fibrous material with a higher hardness in the filler composition forms a network skeleton structure with other component materials during hydration. This structure and the network structure of the paper fiber are mutually embedded, which improves the stiffness of the paper product, Fold resistance, water permeability and air permeability.

Claims

Rights request

1. A filler composition, the main chemical composition of which is as follows: 30-38 parts by weight of SiO ₂ , 15-21 parts by weight of CaO, 17-21 parts by weight of MgO, 2-3 parts by weight of A1 ₂ Ο ₃ , 3.9 -5.9 parts by weight of SO ₄ ² -and 8.8-31 parts by weight of crystal water.

2. The composition according to claim 1, wherein the composition further comprises Fe ₂ O ₃ , Na ₂ O, and K ₂ O, and the total weight part thereof is less than 1% by weight of the entire composition.

3. The composition according to claim 1 or 2, characterized in that the composition is mainly composed of (i) talc, (ii) natural calcium metasilicate, (iii) bentonite, (iv) magnesium oxide or magnesium carbonate, and (V) A surfactant is prepared, and the main chemical composition of the surfactant is as follows: 10-12 parts by weight of SiO ₂ , 7-11 parts by weight of A1 ₂ Ο ₃ , 36-39 parts by weight of SO ₄ ^2- , and 27- 38 parts by weight of crystal water.

4. The composition according to claim 3, wherein the chemical composition of the surfactant further comprises Fe ₂ O ₃ , CaO, Na ₂ O, and K ₂ O, and the total weight of the surfactant is less than the entire surfactant. 7.2% by weight.

5. The composition according to claim 3, wherein the composition further comprises one or more raw materials selected from the group consisting of gypsum, zeolite, sodium aluminum sulfate, polyaluminum sulfate silicate, and hydrated magnesium silicate.

6. The composition according to claim 1 or 2, characterized in that the composition is a white powder with a whiteness of 85%.

7. The composition according to claim 1 or 2, characterized in that the average particle size of the composition is 5-10 microns, wherein the weight percentage content of the fibrous particles is 36-60%, L / D ratio 10.

8. A method for preparing a filler composition, the method comprising the following steps:

Mix raw materials talc, natural calcium metasilicate, bentonite and magnesium oxide or magnesium carbonate, and pre-ground into fine powder;

The two kinds of fine-grained powders are mixed uniformly, and further ground to a particle size of 5-10 microns, the surfactant can be prepared as follows: sulfuric acid solution is added to aluminum hydroxide for acid hydrolysis, and sodium silicate and Optional calcium carbonate and / or sodium sulfate and / or potassium sulfate and / or cationic starch, stir well, cool to crystallize, and dry. 03/093578

9. Use of the filler composition according to any one of claims 1-7 in papermaking.

10. A paper product comprising the filler composition according to any one of claims 1-7.