Process for the manufacture of nano-scale, primary, coated hydrotalcite and hydrotalcite

Abstract

The invention presented concerns a process for the manufacture of coated, nano-scale, hydrotalcites, where the individual, primary, nano-scale hydrotalcite particles are coated. In order to obtain the corresponding hydrotalcite particles in coated, nano-scale form, the additive precipitation reaction is employed invention-related. Every primary particle indicates its own coating in this case. In a further aspect, the registration is directed toward coated primary, nano-scale, hydrotalcite particles, in particular obtainable in accordance with the invention-related process. A further aspect of the invention is directed toward composites containing nano-scale hydrotalcites, in particular hydrotalcites manufactured in accordance with the invention presented. Finally the registration presented is directed towards compositions containing mixtures of magnesium hydroxide and hydrotalcite.

Claims

1. Coated, primary, nano-scale, hydrotalcite particles obtained by a process, comprising: contacting i) a magnesium saline solution with ii) an aluminum saline solution, to obtain a first reaction mixture, adding sodium carbonate and sodium hydroxide to the first reaction mixture, to obtain a second reaction mixture, and precipitating a coated, primary, nano-scale, hydrotalcite particles from the second reaction mixture, wherein one of the solutions i) or ii) comprises at least one additive selected from the group consisting of A and B, optionally in combination with an additive C, or the contacting of i) and ii) further comprises contacting at least one additive selected from the group consisting of A and B, optionally in combination with an additive C, with the first reaction mixture, wherein the additive A is a growth inhibitor, the additive B is a dispersing agent and the additive C is a diluted fatty acid solution, and wherein the primary hydrotalcite particles are each individually coated.

2. The coated, primary, nano-scale hydrotalcite particles of claim 1, wherein the particles have a BET surface area of 50 m.sup.2/g.

3. A composite, comprising: the coated, primary, nano-scale hydrotalcite particles of claim 1, as a filling material.

4. A composition, comprising: 1 to 60 mass % MgOH.sub.2, and 1 to 20 mass % coated, primary, nano-scale hydrotalcite particles according to claim 1.

5. The coated, primary, nano-scale hydrotalcite particles of claim 1, wherein said additive C is present and is a stearate solution.

6. The coated, primary, nano-scale hydrotalcite particles of claim 1, wherein hydrotalcite of the particles has a formula Mg.sub.6Al.sub.2(OH).sub.16CO.sub.3.4H.sub.2O.

7. The composite of claim 3, further comprising a plastic.

8. A process for manufacturing the composite of claim 3, comprising: an extrusion process in which a plastic is mixed with said coated, primary, nano-scale hydrotalcite particles.

9. A composite, comprising: a plastic, coated, primary, nano-scale hydrotalcite particles, as a filling material in the plastic, in a content of from 1 to 20 mass % with respect to the composite, and MgOH.sub.2 in a content of from 1 to 60 mass % with respect to the composite, wherein the coated, primary, nano-scale hydrotalcite particles are obtained by a process, comprising: contacting i) a magnesium saline solution with ii) an aluminum saline solution, to obtain a first reaction mixture, adding sodium carbonate and sodium hydroxide to the first reaction mixture, to obtain a second reaction mixture, and precipitating a coated, primary, nano-scale, hydrotalcite particles from the second reaction mixture, wherein one of the solutions i) or ii) comprises at least one additive selected from the group consisting of A and B, optionally in combination with an additive C, or wherein the contacting of i) and ii) further comprises contacting at least one additive selected from the group consisting of A and B, optionally in combination with an additive C, with the first reaction mixture, wherein the additive A is a growth inhibitor, the additive B is a dispersing agent, and the additive C is a diluted fatty acid solution, wherein the primary hydrotalcite particles are each individually coated, and wherein the composite has a UL94 V0 fire resistance.

10. The composite of claim 9, wherein hydrotalcite of the coated, primary, nano-scale hydrotalcite particles has a formula Mg.sub.6Al.sub.2(OH).sub.16CO.sub.3.4H.sub.2O.

11. A process for manufacturing the coated, primary, nano-scale, hydrotalcite particles of claim 1, the process comprising: contacting i) a magnesium saline solution with ii) an aluminum saline solution, to obtain a first reaction mixture, adding sodium carbonate and sodium hydroxide to the first reaction mixture, to obtain a second reaction mixture, and precipitating coated, primary, nano-scale, hydrotalcite particles from the second reaction mixture, wherein one of the solutions i) or ii) comprises at least one additive selected from the group consisting of A and B, optionally in combination with an additive C, or the contacting of i) and ii) further comprises contacting at least one additive selected from the group consisting of A and B, optionally in combination with an additive C, with the first reaction mixture, wherein the additive A is a growth inhibitor, the additive B is a dispersing agent and the additive C is a diluted fatty acid solution.

12. The process of claim 11, wherein the hydrotalcite comprises Zn.sup.2+ as a further bivalent metal.

13. The process of claim 11, wherein the hydrotalcite comprises at least one anion selected from the group consisting of sulfate, chloride, and nitrate.

14. The process of claim 11, wherein the hydrotalcite has a formula Mg.sub.6Al.sub.2(OH).sub.16CO.sub.3.4H.sub.2O.

15. The process of claim 11, wherein the contacting is performed at a temperature of 0 to 90 C.

16. The process of claim 11, wherein the first reaction mixture comprises the additive B.

17. The process of claim 11, wherein the first reaction mixture comprises 0.1 to 30 mass % of the additive A, based on a solids content of hydrotalcite in the first reaction mixture, and optionally 0.1 to 10 mass % of the additive C, based on a solids content of hydrotalcite in the first reaction mixture.

18. The process of claim 11, which produces nano-scale hydrotalcite particles where at least 90% of the individual particles have a diameter 100 nm.

19. The process of claim 11, wherein said additive C is present and is a stearate solution.

Description

EXAMPLE 1

Manufacture of Hydrotalcite

(1) Experiments with the Use of Coating Additives

(2) Within the framework of this series of experiments, three additives were tested. Two additives from the company Byk-Chemie (DISPERBYK-102 & DISPERBYK-190) and one additive from the manufacturer Ciba (Dispex N40) were used. All three experiments were implemented with high volume flows and at room temperature. The concentration ratio corresponded to that of the Kyowa patent, DE15 92 126 C1, (see footnote Tab. 1). The quantity of additive which was employed in the experiments was approx. 5 Mas %, with reference to the yield of hydrotalcite (approx. 50 g) which was obtained in the experiments. The additive employed was placed into the reaction vessel with 200 ml distilled water. The individual weighed-in quantities and parameters are listed in Table 1.

(3) TABLE-US-00001 TABLE 1 Representation of the laboratory experiments 1 to 2 with coating additive Byk Experiment No. 1 2 Concentration 2* 2* Additive Byk-102 Byk-190 Solution 1 MgCl.sub.2 solution (33%) [g] 172.73 172.73 AlCl.sub.3 6 H.sub.2O [g] 48.16 48.16 Solution 2 NaOH [g] 40.00 40.00 Na.sub.2CO.sub.3 10 H.sub.2O [g] 94.44 94.44 Reaction temperature RT RT [ C. or RT] Volume flow [ml/min] 33.22 33.22 (Flow80) (Flow80) Agitator speed [rpm] 300 300 Post-agitation time [min] 15 15 Receiver (reactor) 200 ml dist. 200 ml dist. H.sub.2O + 2.45 g H.sub.2O + 2.45 g additive additive pH value (reaction end) 8.12 8.40 Yield [%] 81.48 80.16 Hydrotalcite phase* yes yes [Yes/No] Spec. surface [m.sup.2/g] 127.42 73.94 2*: Concentration dependent on the Kyowa patent, DE 15 92 126 C1 (MgCl.sub.2: 0.6 mol/l, AlCl.sub.3: 0.2 mol/l, NaOH: 0.1 mol/l, Na.sub.2C0.sub.3: 0.33 mol/l) RT: Room temperature Flow80: Adjustment on the ismatec hose pump Hydrotalcite phase*: Confirmation through X-ray diffractometry analysis

(4) In the following experiment (see Tab. 2), the above-mentioned Dispex N40 was employed as an additive.

(5) TABLE-US-00002 TABLE 2 Representation with coating additive Dispex Experiment No. 3 Concentration 2* Additive Dispex N40 Solution 1 MgCl.sub.2 solution (33%) [g] 172.73 AlCl.sub.3 6 H.sub.2O [g] 48.16 Solution 2 NaOH [g] 40.00 Na.sub.2CO.sub.3 10 H.sub.2O [g] 94.44 Reaction temperature RT [ C. or RT] Volume flow [ml/min] 33.22 (Flow80) Agitator speed [rpm] 300 Post-agitation time [min] 15 Receiver (reactor) 200 ml dist. H.sub.2O + 2.45 g additive pH value (reaction end) 8.27 Yield [%] 80.32 Hydrotalcite phase Yes [yes/no] Spec. surface [m.sup.2/g] 70.21 2*: Concentration dependent on the Kyowa patent, see footnote Table 1 RT: Room temperature Flow80: Adjustment on the ismatec hose pump Hydrotalcite phase*: Confirmation through X-ray diffractometry analysis

(6) Experiments in the Technical System

(7) The indicated quantities are with reference to a product theoretical yield of 1000 kg.

(8) The yields with the laboratory experiments were approx. 81%.

(9) Experiments 4-5 (Dependent on Kyowa Industrial Property Rights):

(10) TABLE-US-00003 Solution 1 Solution 2 MgCl.sub.2 sol. 33% AlCl.sub.3 6 H20 NaOH sol. 25% Na.sub.2C03 2858.4 kg 796.9 kg 2647.8 kg 579.2 kg

(11) Experiments 6-7:

(12) TABLE-US-00004 Solution 1 Solution 2 MgCl.sub.2 sol. AlCl.sub.3 NaOH sol. 33% 6 H.sub.2O H.sub.2O 25% Na.sub.2CO.sub.3 H.sub.2O 2860.9 kg 797.7 kg 3297.9 kg 2650.10 kg 579.7 kg. 1726.7 kg

(13) In the above experiments 6 and 7, BET values 63 to 67 m.sup.2/g were obtained. As a comparison; the BET values with the product Alcamizer from Kisuma amounted to approximately 8-10 m.sup.2/g (kisuma.com/alcamizer.html).

EXAMPLE 3

Manufacture of PVC Composite

(14) The products obtained from these experiments were employed with the usual processes generally used in the manufacture of the composite materials. The recipe employed is represented in Tab. 3.

(15) TABLE-US-00005 TABLE 3 Recipe for the manufacture of the composite materials KKS KKS CaZn Product 16 17 standard PVC SH 6830 100 100 100 Sorbic acid 911 0.8 Hydrotalcite in accordance with 0.8 the invention presented* Calcium stearate 0.8 0.8 Zinc stearate 0.8 0.8 Rhodiastab 55 0.2 0.2 Mark CZ 2000 2.5 Marklube 367 0.5 0.5 0.5 Paraloid K 125 1 1 1 Licowax PE 520 0.2 0.2 0.2 Loxiol G 60 0.8 0.8 0.8 Kronos 2220 4 4 4 Hydrocarb 95 T 5 5 5 All specifications in parts! KKS 16 = comparison product, sorbic acid 911, Sued-Chemie KKS 17 = composite, with Byk-102, see Vers. 1

(16) In case of the experiments, it was surprisingly indicated that the viscosity of the melted polymer masses was considerably lower than expected. As a result, the extruder temperature could be lowered from 200 C. (with competition product) to 180 C., where the same viscosity was retained as with the competition product. A lower extruder temperature reduces the energy input and lowers costs.

(17) Mechanical Investigation of PVC Composites

(18) TABLE-US-00006 TABLE Mechanical characteristic values of PVC U-profiles Tensile test Impact resistance Sample .sub.M .sub.M E.sub.t 3.sub.cU20 3.sub.cA+23 number [MPa] [%] [MPa] [kJ/m.sup.2] [kJ/m.sup.2] CaZn standard 47.1 2.9 2884 NB 14.6 KKS 16 45.8 3.2 2878 NB 16.7 KKS 17 47.3 3.2 2964 NB 17.2 NB: None Break

(19) Determination of the Acid Capacity

(20) ph measuring device process according to EN ISO 182-2: 1999

(21) Principle of the Method:

(22) 2 g of the substance to be tested is present in a gas flow (N.sub.2) and is heated up to 200 C. The hydrogen chloride gas formed is absorbed in a 0.1 mol/l sodium chloride solution, and in this way the pH value of the solution is lowered. At the beginning of the measurement, the solution has a pH value of 6, the stability time ts is reached with a pH value of 3.8.

(23) Results:

(24) TABLE-US-00007 Sample number ts (min) CaZn standard 71 KKS 16 77 KKS 17 71

(25) The acid capacity of the hydrotalcite manufactured invention-related is in accordance with the determined ts values with the CaZn standard, and comparable with the sorbic acid and provides sufficiently good results.