FI61708C - FRAMEWORK FOR THE PURPOSE OF THE PAPER AND OF THE FOODSTUFFS - Google Patents

Description

nriwTl rBl mv ADVERTISEMENT s + nrsn jgfö [BJ (11) UTLÄGG N I NGSSKRI FT 6,708 ^ 45) Patent · ιy r, 11y 10 09 1902

Patent Med ^ T ^ (51) Kv.lk?/lirt.CI.3 C 09 C 1/28, 1/02, v; C 01 F 11/18 FINLAND —FINLAND (21) Pitenttlhekemut - PMenttiweknln * 3096/7 ^ (22) Hekemlipilvi - Ameknlnpdtg 23-10.

(23) Alkupilvt — GIMihaudu 23.10.7l (41) Gotten swept - Bllvlt offuntllg 25.01.75

Patent and registration holders / age,,,.,.

_. . (44) Date of beam and moon-braided. - -ji OS 82

Patent and registration authorities Antokin utlagd och utl.skrlften publkend (32) (33) (31) Request »1 · *» / privilege — Begird prlorltet 21.10 .73

France-France (FR) 7337970 (71) Lafarge Societe Anonyme, 28, rue Smile-Menier, B.P. 10, 757Ö2 Paris Cedex 16, France-France (FR) (72) Jacques Baudouin, Montelimar, Jean-Pierre Caspar, Le Teil, France-France (FR) (7l) Leitzinger Oy (5l) Method for the mineral mixture used in the paper and paint industry - Förfarande för framställning av en i pappers- och färg-Industrin använd mineralhlandning

The invention relates to a process for the preparation of a mineral mixture containing silicon or silicates used in the paper and paint industry, which process completely hydrates Portland cement with an amount of water to form a paste containing 5-70% by weight of solids which is treated with CCl 2.

Known products currently on the market as fillers are generally the following: Natural or synthetic calcium carbonate, dolomite, barium sulphate, talc, quartz, synthetic silicoaluminates, kaolin, pyrogenic kaolin, natural or synthetic vollastonite.

The starting material used in accordance with the present invention, hereinafter referred to as the "anhydrate material", is white cement, i. white portland cement. These products contain di- and tricalcium silicates mainly as anhydrates. Other products called white lime, which are rich in di- or tricalcium 2 617 0 8 silicates, may also be used. Finally, only these silicates, in particular tricalcium silicate, can also be used. These products can be used in clinker form, i.e. removal of the kiln as roasted granules, in which case they are comminuted before hydration.

In the process according to the invention, a commercial form of artificial Portland cement (C.P.A.), which is a whiter variant, or also any other mixture of C.P.A., to which white additives (gypsum, white pozzolan) have been added, can be used.

This process is characterized in that the carbonation is continued until the pH drops from 12.4 to less than 11, and the product obtained containing 30 to 85% by weight of calcium carbonate is recovered and the remainder consists mainly of tobermorite and / or hydrated silica, which oxide calculated as silica, constitutes not more than 15% by weight of the final product.

The hydration reaction gives a mixture of hydrates containing mainly hydrated calcium silicates, commonly referred to as tobermorite of the formula X * Ca0 * ySiO 2 * zH 2 O, wherein ^ is 0.40 to 3.00 and is 0.5 to 6, and hydrated lime Ca ( OH) 2 · In this case, it should be noted that a special case of tobermorite is afwilite, whose chemical compositions are 3 CaO, 2 SiO 2 and 2-4 H 2 O.

After hydration, which can be very easily monitored by crystallographic analyzes by X-ray diffraction, carbonation of the hydrated lime is started. Carbonation occurs by passing carbon dioxide into an aqueous and mixed hydrate paste or by mixing this paste together with sodium bicarbonate or other substances that release carbon dioxide. Of particular interest as carbon dioxide sources is the use of exhaust gases from incinerators used to heat the hydration vessel after purification by filtration or washing.

It may be of particular interest to use a cement kiln exhaust gas containing about 20% by volume of carbon dioxide as the carbon dioxide source.

3 61708

The carbonation takes place between 20 and 100 ° C. This is done so that all the lime is carbonized. The cessation of this carbonation is easily detected by measuring a pH of 12.4 as long as there is still lime in the reaction vessel, which drops rapidly to at least 11 when free lime is no longer present. Depending on the conditions of hydration and carbonation, tobermorite is obtained which contains different amounts of calcium, which is perfectly normal because the term "tobermorite" refers to the group formed by the products used. In the borderline case, when highly forced carbonation is carried out after hydration or when carbonation is carried out during hydration, hydrated silica is obtained instead of tobermorite and in addition to carbonate.

By means of the invention it is possible to obtain mixtures continuously which comply with the above-mentioned limit values.

The method directly yields a paste which is an aqueous suspension of a mixture of tobermorite and / or afwilite and calcium carbonate. This paste can be concentrated in the usual way, for example by filtration with a filter press. Drying by conventional methods, for example by spraying, can also be used to dry the minerals.

The preparation of the mixture according to the invention is described below.

Example 1

Commercial white Portland cement with the following composition:

SiO 2: 23.7 parts by weight

CaO: 69.3 Al 2 O 3: 2.7

Fe 2 O 3: 0,28 SO 3: 1,19 volatile matter: 1,80 parts by weight insoluble matter: 0,11 parts by weight and impurities up to 100 parts by weight are added to a corundum crusher filled with corundum balls and water as follows: - the balls fill one third of the volume - water and cement fill one third. Water is added in three ..Jcerta the weight of the cement. The remaining third is left free to allow crushing. The hydration takes place at 4 61 708 60 ° C. Classical analytical equipment in the cement industry (X-ray diffraction and determination of the percentage of bound water) showed that the hydration had been completed after 15 hours of crushing and that the product thus formed was a tobermorite with a mixture of afwilite and hydrated lime.

The crusher was then mixed with carbon dioxide by one of the above methods and crushing was continued for 2 hours. Thereafter, X-ray diffraction showed that a mixture of hydrate 3 CaO, 2 SiO 2, 3 H 2 O and calcium carbonate, i.e. the desired filler, had been obtained. Determination of the amounts of bound water and carbon dioxide gas released at different temperatures revealed that the mixture consisted half of each of said salts. The reaction yield indicates that 100 parts by weight of cement had bound 25 parts by weight of water and then 25 parts by weight of carbon dioxide to give 150 parts by weight of the desired filler.

Under these conditions, the resulting paste has a dry matter content of 35.3%.

The paste was then passed to a filter press and slurried at a pressure of 10 bar to concentrate the running paste to a thick paste, for example 50%. This paste can be used in many of the mentioned uses. The pasta can also be dried, for example by killing.

In this example, after drying, a white powder with the following properties is obtained: - Grain size, measured with a laser grain meter: 100% less than 8 μ - average particle diameter: 2 μ - degree of whiteness, measured in photovolt at λ = 574.5 mp: degree of whiteness 8 = 95 , 2% 2 - specific surface area (method BET) = 13.1 m / g - oil absorption (by the method Rub out Test; standard AFNOR T 30-022): 55 g / 100 g - solubility in water: 0.83 g / 100 g (Codex method) - abrasion resistance (Valey method): 15 milligrams - pH in saturated water: 10.7 - loss on ignition at 1000 ° C: 36.4% by weight - density: 2.15 - chemical analysis of the powder obtained after loss on ignition At 1000 ° C is as follows: 5 617 0 3

SiO 2> 22.25% by weight

CaO 70.81 A12C3 2.65 -

MgO 0.53 K 2 O, Na 2 O 0.1

When dispersed in a liquid, the filler formed from this powder sediments very slowly due to the high specific surface area and low density of the powder and can be used as an anti-settling agent. In a thicker paste form, for example with a dry matter content of 40% in water, the filler according to the invention has a dixotropic rheological property as a result of ion exchange of free water and hydrate crystal water, which is highly desirable in color and paper coating techniques.

Example 2 The starting material used is the substance of Example 1, which is hydrated and then carbonated as described in another publication of the Applicant. According to this publication, the reaction takes place substantially faster, takes only a few hours and a mixture according to the invention is obtained at a reasonable price, depending on the starting materials used in each case. In each case, the required temperatures, amounts of water, mixing times, amounts of carbon dioxide gas, etc. can be determined by preliminary experiments. The following description gives Examples of Use of the mixture according to the invention which can be used as a dry powder or aqueous dispersion. The best mode of operation can be determined in each case by preliminary tests.

1. Paper industry 1) A coating liquid with the following composition is prepared in the usual way:

The filler according to the invention is 100 parts by weight

Water 100

Dispersant (eg Polysel, BASF) 1 "

Acrylic emulsion (Acronal 290 D, BASF), dry matter content 50% 20 "Starch solution, dry matter content 25% 40"

Calcium stearate 1 "

Anti-cryptographic additive 0.2 "61708 This coating liquid had the following properties: - Dry matter content 46.2% - pH 11.1 - Viscosity - 10 rpm 580 cp - Viscosity, 100 rpm 500 cp - Grain size 100% less than 8 microns.

Coating of plain raw paper gave the following properties: - Weight of applied coating: 10.40 g / m / page - Opacity of coated paper (coated on one side only): 88.2% - Whiteness: 89% 2) Coating liquids were prepared with the following compositions A, B, C in order to compare a good quality, classic kaolin for coating with a filler according to the invention.

The general composition is the same as in Example (1), but the amounts of filler were replaced by the amounts given below, and the amounts of water were adjusted so that in all cases a constant amount of dry matter was obtained: Filler composition_A_B_c

Kaolin, quality Dinkie A 100 80 0

Filler according to the invention 0 20 100 (parts by weight)

The coating liquids obtained had the following properties:

Composition abc

Dry matter content (weight) 50% 50% 50% pH value (without correction) 6.3 11.1 12.0

Grain size 100% <8 μ: 100% <8 ju: 100% <8 m

Viscosity in centipoise measured with a Brookfield viscosity meter 10 rpm. 5800 6800 7100 100 rpm. 860 1200 1450 7 61708

The properties measured on plain raw paper under the same conditions and with the same adjustments were as follows:

Composition AB C

2 Coating weight, g / m / page 12.4 11.7 8.8

Opacity (coated on one side only 96.4 96.7 97.3 Adhesion of the coating to the corresponding Dennison-Wachses tear n ° 11 11 11

Degree of whiteness 80 84 87 These examples show that the filler according to the invention is very well suited for coating paper and has properties which are well received in the paper industry: - Fineness and satisfactory degree of whiteness - Opacity is better than what can be achieved with the best known kaolins - Alkaline pH, which gives the coating liquids a basic character without having to adjust the pH. This results in very good stability of coating liquids containing synthetic dispersions, as these are stable only in an alkaline environment.

- Lower coating weight (on the order of 7.5%) with an equal coating volume due to the low density of the filler according to the invention.

The results given above show particularly well the fact that the filler according to the invention allows lighter coatings. Thus, when the weight of the coating is considered as a set criterion, a thicker layer can be applied using the filler according to the invention, making it possible to use paper with a more uneven surface and thus of lower quality. By using the filler according to the invention, it is also possible to apply coatings of normal thickness and thus save on the weight of the paper, which is important when it is necessary to transport the coated paper.

It can be seen from the above examples A, B and C that with the same machine controls and the same dry matter content of the coating liquid, i. with the same dry coating volumes, the weight of the coating can be reduced by 5.6% by using a mixture of fillers with 20% of the filler according to the invention and by 30% by weight of the coating using the filler according to the invention alone compared to a composition using only kaolin- 3) Both of the following the examples illustrate particularly well the other advantages which can be obtained with the filler according to the invention. The pigments and binders of the filler of Example 1 are replaced with the amounts mentioned below, the remainder of the composition corresponding to composition 1, and optionally an optical brightener is added. The mixture is prepared by kneading. Dispersion and viscosity control take place in the normal manner in the industry in question. The pH is not adjusted, but is given the following values:

Composition D

Kaolin 100 parts by weight Starch (dry) 8.5 "

Latex Dry) 8.5 "

Composition E

Filler according to the invention 100 parts by weight Starch (dry) 9.5 "

Latex (dry) 9.5 "This composition is made so that a dry matter content of 42.5% by weight is obtained during use. The use is carried out with 2 coatings of 12 g / m 2 per side. Under these conditions, the following results were obtained for coated paper.

Composition D Composition E

Filler kaolin Filler according to the invention Coating liquid pH 6.8 11

Dry matter content in use 42.5% 42.5% 2 2

Weight of applied coating 12 g / m / page 12 g / m / page Degree of whiteness of coated paper 81.9 89.5 Opacity of coated paper 87.8 88.7

Azurant optique 2.8% 4.5% 9 61 708 This example clearly shows the benefits in terms of whiteness, opacity and bleach utility resulting from the use of the filler of the invention.

II. Dyes Starting from the products according to the invention, paints and brushes can be prepared in aqueous dispersion or dry, in particular brushes for structures based on vinyl emulsion, acrylic emulsion, polyurethane emulsion, etc. Due to its basic nature, the filler also adapts very well to dyes and anti-corrosion impregnants, which can be realized with non-acidic binders. Due to its ideological properties, the filler can be used as a thickener and an anti-settling agent.

Example 1

Acrylic emulsion-based decorative mortar.

A construction paint and in particular a decorative mortar based on a synthetic binder is produced. Such a dye is highly desirable due to its decorative effect and relay property, which can very well cover structural defects.

Knead the serum substances by mixing the following substances in Part I until the filler is well dispersed: {Water (parts by weight) 9

25% solution of deflocculant 0.1

Filler according to the invention 24

Titanium dioxide, anatase 1

Acrylic dispersion, dry matter content 50% (Styroform, BASF) 27 5% methylcellulose solution 3

Butyl glycol 1 \ Dioctyl phthalate 0.5 \ Defoamer 0.05 followed by 10 61 708

Washed river sand, 0.8 - 2imu 5

Fine quartz sand 30

The sand is slowly dispersed in the rest of the mixture. Then add enough water to give a brush viscosity of 3500 cp (Brookfield viscometer, 10 rpm).

In this way, a thixotropic brush color having the following properties is obtained: pH = 10.7

Dry matter content = 73.8%

Pigment / binder ratio = 4.36 / 1 This can be applied to the brush with a spa coat, brush or rubber roller, etc. It can also be plastered to give a decorative effect. The main advantages due to the use of the filler according to the invention are: - Thixotropicity, which is formed by means of the filler and which allows the application of thicker layers without droplet formation.

- Alkalinity of the filler, resulting in a time-stable mortar and no need to adjust the pH during manufacture.

- High degree of whiteness and opacity, caused by high fineness, which makes it possible to reduce the amount of titanium dioxide added.

Example 2

White emulsion color.

The following color is produced: _Weight Percentage

Water 60 23.4

Tripolyphosphate, 5% 4 1.5

Filler according to the invention 60 23.4 50% vinyl emulsion "Afcolac 50 '80 31.2

Titanium dioxide, rutile 7.8

Colloidal "Matrosol" preservative, 5% solution 15 6

Dioctyl phthalate 2 1

Butyl glycol 4 2 Tall oil 1 0.5

Water for viscosity adjustment 10 4

A total of 256 loo.R

11 61708 This paint has a dry matter content of 47%. The pigment / binder ratio is 2. The viscosity is 300 cp with a Brookfield viscometer, 10 rpm. No pH adjustment is required during manufacture and the stability remains good for a long time. The color is dixotropic, can be applied easily and not drip after application.