CS229797B1 - Filling agent on the natural or synthetic carbonyl base - Google Patents

Abstract

The invention relates to natural-based fillers or synthetic carbonates. Perfectly a homogenized mixture of 50 to 99.9 parts by weight of carbonates and 0.1 to 0.1% by weight 50 parts by weight of silicates particles of 0.05 to 10 µg are impregnated silane or titanate linkers agents that hydrophobise the filler perfectly so composite materials they have higher strength than carbonate composites fillers and surface hydrophobized fatty acids.

Description

The invention relates to fillers and pigments for plastics, paints and extenders of rubber mixtures based on natural or artificial carbonates.

Carbonate raw materials, especially natural finely ground calcium carbonate, have found use as fillers, pigments or extenders, especially in the paint, rubber or plastics industry due to their properties and affordability.

From these areas of the most useful carbonate fillers, it is clear that the primary environment in which the inorganic fillers are found is organic, most often polymeric matrices, which presents two main problems: the need to suppress undesirable chemical interactions of the inorganic filler surface with the organic matrix

- the necessity of treating the inorganic surface in such a way as to make it organophilic and thus make it easier to disperse in the organic matrix, to be compatible with one another and thus to combine the two phases well.

The first group of problems is influenced by the physical nature of the filler surface and its chemical composition, ie the original and further induced crystal lattice, morphology and isomorphic substitution of the carrier carbonate cation, together with the manifestation of anisominerally present accompanying impurities, when these materials are exposed to elevated temperatures and mechamatic stress, they always have an adverse effect. The prerequisite for successful solution of these questions is selective extraction, knowledge of the chemical and mineralogical composition of the extracted material and finally optimization of grinding and sorting processes.

Questions of the second group associated with the surface treatment are decisive for the behavior of the fillers in the matrix and also affect the degree of desired properties of the final composite.

The basic property of fillers, generally applicable and required for all inorganic fillers, is the compatibility of the filler with the matrix.

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This will be the better the more inorganic surface the organophile is. This can be achieved by providing an inorganic surface with an organic deposit, preferably one that is chemically bonded to the filler surface and at the same time having the possibility of interacting with the surrounding organic environment. Substances that meet these requirements are called binding agents and their representatives are compounds having preferably two kinds of functional groups · One that provides a connection to the inorganic surface and the other to the surrounding organic, most often polymeric environment. Such typical binding agents are, for example, multifunctional compounds based on organosilanes or organotitanates.

However, in the case of carbonate fillers, the use of these binding means is considerably disadvantaged. This is due to the composition of the crystal lattice of carbonates, which lack structurally integrated and interactively satisfactory functional groups, such as -OH groups. Therefore, in the case of cabonates of the application of the multifunctional fasteners, the forces with which these agents are surface-bound are of a low dispersion strength. And if some of the coupling agent males, especially multifunctional ones, are bonded chemically, only to the water molecules, which in turn are only physically bound to the surface of the particles. Therefore, only monofunctional higher fatty acid binding agents are used in carbonate fillers.

As a result, the applicability of carbonate fillers is limited, especially where not only an increase but also a long-term preservation of the strength characteristics of the composites is required.

A continuous study of the properties of carbonate fillers has now shown that even disadvantaged fillers can be modified to be useful in areas of application that require surface treatment with multiple or monofunctional fasteners to form chemical bonds.

The present invention provides a filler based on natural or synthetic carbonates and silicates with a hydrophobized surface, consisting of 50 to 99.9 parts by weight of carbonates and 0.1 to 50 parts by weight of silicates having a particle size of 0.05 to 10 µm, perfectly homogenized and after homogenization impregnated with silane or titanate fasteners.

The most typical representative of carbonate fillers is natural calcium carbonate, whose mineralogical representative is kaloite.

The basic crystal cell of calcite consists of a gem in which corners and in the center of the surfaces are located Ca ²⁺ cations and planar CO ² anions then in the middle of the edges. This essentially determines the ion density

229 797 at individual crystal sites, thus the unsaturation of binding forces and hence the intensity of force fields, which besides these factors are modified by natural anomalies and crystal lattice defects, by the representation of calcium cation by isomorphic calcite cations, ie magnesium, manganese, iron, zinc, cadmium, cobalt, strontium or lead, as well as anisomineral admixtures present both in isolation and in paddles and, finally, morphological disturbances caused by crushing and grinding, including inhomogeneities due to graded density uneven material ·

Thus, both the physical and chemical nature of the surface so formed is the result of all of the above-mentioned factors, which are already inevitable when applying fasteners.

If a binding agent is required to produce relatively strong, preferably chemical bonds, between its molecules and the filler surface, the surface of the carbonate fillers alone provides only a negligible possibility for such interaction, since for example, the limestone crystal lattice contains virtually none of the desired functional groups suitable for such interaction. And if there are any functional groups on the surface, for example -OH groups, only as an ionized part of the physically or very sporadically chemisorbed-bound water molecules.

Therefore, for carbonate fillers, the use of coupling agents requiring, for example, a reactive, structural -OH group for discussion is questionable and practically inconclusive, and the use of modifiers in practice and documented in practice is limited mainly to monofunctional agents such as higher fatty acids and derivatives or lubricants based polyethylene or polypropylene oxides, all of which are only organophillicity enhancers, the bonding of these modifiers to the filler surfaces being effected only by weak dispersion forces.

However, carbonate fillers, pigments, or extenders can be successfully modified to be able to form a solid and solid filler-matrix bond, admixtures of secondary fillers that are with carbo-. They are miscible by the fillers and contain structurally bound and surface-localized reactive groups which, when interacting with the binding agents, form a chemical bond. The appropriate type, amount and size distribution of the secondary filler particles, the choice and concentration of the binder together with the choice of the environment and the conditions of formation and fixation of the binder, will be formed on the particle surface.

229 797 of a mixed filler, a continuous network of fasteners, both chemical and rtsparative forces anchored on both the secondary or filler particles and on the carbonate particles, allowing the desired interaction with the organic matrix.

One of the prerequisites for the successful usability of the secondary filler is its miscibility and compatibility with the carbonate filler, which θ

depends on the structural and ohmic composition of both fillers ·

On the surface of carbonate fillers, crystal corners, ie cation positions that exhibit maximum unsaturated binding forces, are the most important sites for the secondary filler interactions. Therefore, the choice of secondary fillers will preferably be focused on those that not only contain structurally bound and surface localized reactive -OH groups, but also centers that are capable of both cation exchange and catalysis of interaction processes ·

All aluminosilicates and other structurally compliant compounds, such as the silicates themselves, such as activated silicas or alumina with a minimum SiO ₂ content, clearly meet these requirements.

Typical representatives of such materials are natural or synthetic silicates or their weathered forms - aqueous silicates, clays and their constituents, calcareous clays or claystones.

The most suitable are those that are industrially processed and therefore available in the desired range and properties · These are, for example, kaolins, bentonites, mica, talc, silica and the like, characterized in addition to structurally suitable properties and suitable hardness, comparable to hardness carbonates ·

If a portion of the carbonate filler in an amount of 0.1 to 50% by weight is replaced by a silicate filler which contains structurally bound and surface localized reactive functional groups, preferably hydroxyl, capable of interacting with the coupling agents, the structurally bound reactive centers preferably Brondsted type capable not only exchanges with cationic lattices of carbonate fillers, pigments and extenders, as well as catalysis of the respective interaction reactions and their polydispersity, chemical composition, density and hardness, make a mixture compatible with the primary carbonate filler, pigment or extender, thus allowing mixed filler particles , pigment or extenders, so as to form a solidly embedded polymer network-like build-up of fasteners, especially multifunctional agents, on their surface, capable of further, subsequent interactions polymeric or polymeric matrices. ⁷⁹⁷

As a result, the carbonate fillers, pigments and extenders obtain such a significant improvement in their surface properties that they can advantageously be used even in areas not previously used.

The process for preparing such a mixed filler may be as follows: The mixture of limestone fillers ground and sized to a medium grain size of loyum and a fine kaolin fraction of medium particle size 1-2 / tm is agitated in a fluidized-bed mixer for 30 minutes. solution or preferably according to AO 188553, i.e. also in a rapid mixer, impregnated with a multifunctional silane or titanate coupling agent.

The same effect is obtained by a process whereby the coarsely ground limestone raw material is ground in the presence of an alumosilicate, for example in a pneumatic mill, for 30 minutes and then screened to the desired fraction, treated with a binder according to the above procedure.

The following examples illustrate the invention in more detail, in which parts or percentages are by weight unless otherwise noted.

Example 1

Limestone from the Devil's Stairs site, containing an analysis of 2.9% insoluble matter (15% HCl), in the soluble phase of 98 ppm Pe, ppm Mn and 12 ppm Cu, was ground and graded to the following grain size:

2% below 2µm, 4.8% below 10µm, 77% below 15µm and 91% below 20µm mean particle size at 50% was 10µm.

100 g of this filler was impregnated with silane A 1100 (gammaaminopropyltriethoxysilane) in an amount of 0.5% per filler as follows: in a 400 ml beaker was mixed ^ 100 g of limestone in 100 ml of ethanol / water 9: 1. 50 ml of ethanol / water 9: 1 containing 0.5 g of silane A 1100 and stirred at room temperature for 2 hours. The slurry was then poured into a flat crystallization dish and dried in a laboratory hot air oven at 130 ° C for 8 hours. After drying, the product was pulverized by grinding in a laboratory ball porcelain mill with agate balls for 1 hour, at room temperature and at 2 rpm.

After storage for one week, in a polyethylene bag under laboratory conditions, the treated sample was subjected to amino silane deposition analysis as described in AO 195896 of June 15, 1982, where, in addition to the total amount of silane deposition, it was determined.

229 797 and its chemisorbed, i.e. chemically bound fraction of the filler.

In this case, it was found that only 12% -2.5% of the silanes originally used were chemisorbed.

Example 2 g of limestone from the Devil's Stairs site as described in Examples 1 and 20 of kaolin oz. DS-ex, Chlumčany, sorted to a mixture with a maximum particle size of 5 µm and a main fraction of 1-3 µm, was mixed and shaken on a laboratory shaker at room temperature for 3 h. The mixture was then impregnated with 0.5% aminosilane A 1100 as per Example 1. The silane deposit analysis was performed in the same manner and found to contain 71% -3% chemisorbed. Example 3

Limestone from the Bohdaneč site, containing an analysis of 14.3% insoluble matter (15% HCl) in the soluble phase of 1050 ppm Pe, 480 ppm Mn and 28 ppm Cu, was ground and screened for the following grain: 7% below 2%, 46% below 10 µm, 70% below 15 µm and 86% below 20 µm mean size at 50% was 11.5 µm.

200 g of this filler was mixed in 100 ml of distilled water and 100 ml of a 2% ethanolic solution of silanes A 1160 (urea-modified aminosilane) were added with stirring to the resulting suspension. The resulting suspension was stirred, dried and ground as in Example 1 and in the same manner as Analyzed 12.8 - 3% of the silanes were chemisorbed from the original amount of silanes used.

Example 4 g of limestone from Example 3 and 15 g of talc with a particle distribution of up to 10 µm were mixed and 2 hfcA shaken. 100 g of the thus obtained mixture were impregnated with aminosilane A 1100 as in Example 1 and analyzed in the same way for the tightly bound silanes.

63-5% of chemisorbed silanes were found.

Example 5 g of the limestone of Example 1 and 1 g of precipitated silica with a particle distribution of up to 0.2 µm and a surface area of 158 m / g were impregnated with aminosilane A 1100 after mixing and 2 shaking at 110-115 ° C and analyzed as in Example 1. The mixture thus prepared showed a 73.0 ± 5% chemisorbed fraction.

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Example 6

100 g of synthetic, precipitated CaCO 2 with a maximum particle size of 2 µa. was mixed with 0.5 g of silica of Example 5 and shaken at 110-115 ° C. The mixture was then impregnated with thick A 1160 and analyzed in the same manner as the sample in Example 3. The chemisorbed fraction found was 65.5 - 3% ·

Example 7

100 g of the limestone of Example 1 was suspended in 100 ml of ethanol / water 9: 1 with stirring, and after the addition of 100 ml of a 1% ethanol solution of vinyltriethoxysilane A 151, the suspension was stirred at room temperature for 2 hours. It was then dried by heating in a hot-air oven at 130 ° C for 16 hours and homogenized by milling in a laboratory porcelain ball mill with corundum balls.

parts of the thus obtained filler and 60 parts of linear polyethylene DGH 5220 were homogenized by kneading in a Brabender laboratory kneader, at 200 ° C for 25 min. Test specimens were pressed from the obtained composite at 220 ° C to give the following data when determining the notch toughness by the CHARPY method:

Sample of composite Polyethylene / Notch toughness ratio ____, filler ___ tost ^ CHARPY ^^ k

Polyethylene / limestone 1

DGH 5220 unassigned 60/40 14.6

Polyethylene / limestone 1 'DGH 5220 modified according to this example

60/40

15.9

Example 8 100g of dolomitic limestone, ground and sorted for distribution with a maximum particle content of up to 25 µm and a main fraction of 7-8 µm, was impregnated with aminosilane A 1100 at 0.5% in the same manner as in Example 1.

100 g of dolomitic limestone of the above-mentioned grain size was mixed with 20% finely ground, calcined and sorted mica (muscovite, iron content 0.08%, maximum fraction of mean particle size 5 / am) and after shaking for 1 hour the mixture was impregnated with , in the same way and in the same amount as dolomitic limestone. For polyethylene composite test specimens prepared with these fillers in the same manner as in Example 7, the following modulus values were found:

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Sample PE / filler ratio

Modulus of elasticity ________

Polyethylene DGH 5220 PE / dolomitic composite DGH 5220 limestone with treatment A 1100 60/40 Composite ΡΞ / dolomite mixture. DGH 5220 limestone + flyfly with modification A 1100 60/40 PE composite / 80% dolomite mixture. DGH 5220 limestone without silane preparation + 2 0% rausko vit u with modification A 1100 60/40

0.91

1.60

2.25

1.83

Example 9

100 g of precipitated CaCO 2, as specified in Example 6, was slurried in 100 ml of ethanol / water 9: 1 and 100 ml of ethanol containing 0.75 g of triisostearoyl isopropyl titanate were added under stirring. After stirring at room temperature for 2 h, the suspension was dried in a hot-air oven at 125 ° C for 16 hours. It was then milled as in Example 7.

100 g of the mixture obtained by mixing and 1 shaking 95 g of precipitated CaCO 3 from Example 6 and 5 g of silica from the same example were impregnated with titanate, dried and ground in the same manner as the limestone filler in this example. according to Example 7, test bodies of composites with polyethylene DGH 5220 were prepared, which provided the following impact tensile strengths:

Polyethylene composite DGH 5220 / filler 60/40 impact toughness ________________________ Á, .foC-1. Alone CaCO2 treated with titanate 95

CaCO 3 / silica mixture, titanate treated 162

Example 10 parts of limestone grit with an average particle size of 5 mm, characterized by the same chemical composition as in Example 1, and 2 parts of DS-ex kaolin of Example 2 were together in a MAJAC laboratory pneumatic grinder, HETZSCH system for 30 minutes.

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The mixture thus obtained was impregnated with aminosilane at 1100 in an amount of 0.5% per mixture as described in Example 1, and the silane deposit analysis was carried out in the same manner. The amount of chemisorbed fraction in this case was 73-2%.

Claims (1)

Fillers based on natural or synthetic carbonates and silicates with a hydrophobized surface, characterized in that it consists of 50 to 99.9 parts by weight of carbonates and 0.1 to 50 parts by weight of silicates with a particle size of 0.05 to 10 perfectly homogenized and impregnated with silanoate after homogenization or titanate binding agents.