ALKYL SILICONE RESIN AS ADDITIVE FOR HYROPHOBISING FIBRE CEMENT

Abstract

Alkylsilicone resins containing at least 20 mol percent of siloxy units bearing a >C.sub.s alkyl group and having from 5-20 weight percent of alkoxy groups may be prepared directly by hydrolysis of chlorosilanes, and are highly effective as bulk hydrophobing agents in the preparation of fibrocement.

Claims

1.-9. (canceled)

10. An alkyl silicone resin (A) containing at least 80% by weight of units of the formula I
R.sup.1.sub.a(R.sup.2O).sub.bR.sup.3.sub.cSiO.sub.(4−a−b−c)/2  (I), where R.sup.1 are identical or different and are each a monovalent, SiC-bonded, unsubstituted or substituted aliphatic hydrocarbon radical having not more than 4 carbon atoms, R.sup.2 are identical or different and are each a monovalent, unsubstituted or substituted hydrocarbon radical having not more than 4 carbon atoms, R.sup.3 are identical or different and are each a monovalent, SiC-bonded, unsubstituted or substituted hydrocarbon radical having at least 5 carbon atoms, a is 0, 1, 2 or 3, b is 0, 1, 2 or 3, and c is 0, 1 or 2, with the proviso that the sum of a+b+c is less than or equal to 3 and in at least 50% of the units of the formula (I) the sum a+b is 0 or 1 and in at least 20% of the units of the formula (I) c is 1, where the content of alkoxy groups R.sup.2O is 5-20% by weight.

11. The alkyl silicone resin (A) of claim 10, wherein the radicals R.sup.2 are selected from the group consisting of methyl radicals, and ethyl radicals, and mixtures thereof.

12. The alkyl silicone resin (A) of claim 10, wherein at least 90 mol % of all radicals R.sup.1 are methyl radicals.

13. The alkyl silicone resin (A) of claim 10, which comprises, based on the total number of units of the general formula (I), from 8 to 65% of units of the formula (I) in which b is 0.

14. The alkyl silicone resin (A) of claim 10, which comprises, based on the total number of units of the formula (I), from 30 to 70% of units of the formula (I) in which b is 1.

15. A process for producing an alkyl silicone resin (A) of claim 10, comprising: reacting chlorosilane of the formula (II)
R.sup.1.sub.aR.sup.3.sub.cSiCl.sub.(4−a−c)  (II), alcohol of the formula (III)
R.sup.2OH  (III) and water, the reaction taking place in a reaction column in a continuous process, with the alcohol and the water being introduced in the lower part of the column and vaporized there and the alkyl chlorosilane being fed in in the upper part of the column, where R.sup.1 are identical or different and are each a monovalent, SiC-bonded, unsubstituted or substituted aliphatic hydrocarbon radical having not more than 4 carbon atoms, R.sup.2 are identical or different and are each a monovalent, unsubstituted or substituted hydrocarbon radical having not more than 4 carbon atoms, R.sup.3 are identical or different and are each a monovalent, SiC-bonded, unsubstituted or substituted hydrocarbon radical having at least 5 carbon atoms, a is 0, 1, 2 or 3, and c is 0, 1 or 2, with the proviso that c is 1 in at least 20% of the units of the formula (I).

16. The process of claim 15, wherein the radicals R.sup.2 are selected from the group consisting of methyl radicals, and ethyl radicals, and mixtures thereof.

17. The process of claim 15, wherein at least 90 mol % of all radicals R′ are methyl radicals.

18. The process of claim 15, which comprises, based on the total number of units of the general formula (I), from 8 to 65% of units of the formula (I) in which b is 0.

19. The process of claim 15, which comprises, based on the total number of units of the formula (I), from 30 to 70% of units of the formula (I) in which b is 1.

20. A process for the bulk hydrophobicization of fibrocement, comprising preparing a mixture containing water, fibers, cement and alkyl silicone resin (A) of claim 10.

21. A process for the bulk hydrophobicization of fibrocement, comprising preparing a mixture containing water, fibers, cement and alkyl silicone resin (A) produced by the process of claim 15.

22. In a process for the bulk hydrophobicization of fibrocement wherein a hydrophobicizing agent is added to an aqueous mixture used to prepare a fibrocement product, the improvement comprising employing an alkyl silicone resin (A) of claim 10 as at least one hydrophobicizing agent.

Description

EXAMPLES

Production Example 1: Production of a Silicone Resin According to the Invention Having 1,4,4-Trimethylpentyl Groups

[0092] The continuous production process for the silicone resin of the invention is carried out using a double-column plant which consists of a first reaction column which has a length of 4.4 m and a diameter of 50 mm and is filled with ceramic packing elements (ceramic saddles) having a size of 0.5 inch, and an identical stripping second column. The liquid-phase volume of each of the columns is 2000 ml. The throughput of starting material in each experiment is 9-10 kg of 1,4,4-trimethylpentyltrichlorosilane. The residence time is from 60 to 70 minutes.

[0093] Over a period of 6 hours, 9.00 kg of 1,4,4-trimethylpentyl-trichlorosilane are supplied at a metering rate of 1500 g/h to the top of the first column. At the same time, 1.18 kg of ethanol at a metering rate of 197 g/h and 0.72 kg of water (demineralized) at a metering rate of 120 g/h are each introduced into the bottom of the first column. At the same time and likewise over a period of 6 hours, 0.24 kg of ethanol are introduced at a metering rate of 40 g/h into the bottom of the second column.

[0094] The overhead distillate from the first column is recirculated to the top of the first column. The overhead distillate from the second column is recirculated to the bottom of the first column. The temperature at the bottom of the column 1 is 85° C. (+/−4° C.). The temperature at the bottom of the second column 2 is 114° C. (+/−4° C.). The starting materials thus react according to the countercurrent principle to give the desired product which is obtained as a solution in ethanol.

[0095] The crude product produced in this way is neutralized with a solution of 30% of sodium methoxide in methanol, filtered and freed of low boilers, e.g. ethanol, by distillation.

[0096] The treated product (resin 1) contains less than 20 ppm of HCl. It is analyzed by means of .sup.1H/.sup.29Si NMR and by GPC. The determination of the viscosity is carried out as described above. The data obtained are shown in table 1.

Production Example 2: Production of a Silicone Resin Having 1,4,4-Trimethylpentyl Groups

[0097] The same plant as in production example 1 is used.

[0098] Over a period of 7 hours, 10 kg of 1,4,4-trimethylpentyl-trichlorosilane are supplied at a metering rate of 1500 g/h to the top of the first column. At the same time and likewise over a period of 6 hours, 1.38 kg of ethanol at a metering rate of 197 g/h and 1.38 kg of water (demineralized) at a metering rate of 197 g/h are each introduced into the bottom of the first column. At the same time and likewise over a period of 6 hours, 0.30 kg of ethanol are introduced at a metering rate of 43 g/h into the bottom of the second column.

[0099] The overhead distillate from the first column is recirculated to the top of the first column. The overhead distillate from the second column is recirculated into the bottom of the first column. The temperature at the bottom of the first column is 80° C. (+/−2° C.). The temperature at the bottom of the second column is 106° C. (+/−2° C.). The starting materials thus react according to the countercurrent principle to give the desired product which is obtained as a solution in ethanol.

[0100] The crude product produced in this way is neutralized with a solution of 30% of sodium methoxide in methanol, filtered and freed of low boilers, e.g. ethanol, by distillation.

[0101] The treated product (resin 2) contains less than 20 ppm of HCl. It is analyzed by means of .sup.1H/.sup.29Si NMR and by GPC. The determination of the viscosity is carried out as described above. The data obtained are shown in table 1.

TABLE-US-00001 TABLE 1 Analytical Parameter determined method used Resin 1 Resin 2 Ratio of water/EtOH used 1:0.77 1:0.48 [mol/mol] Content of alkoxy groups .sup.1H-NMR 10.4 10.6 [% by weight] Content of —Si(OEt).sub.3 .sup.29Si-NMR 0.4 0.0 [mol %] Content of —Si(OEt).sub.2O.sub.1/2 .sup.29Si-NMR 26.2 24.1 [mol %] Content of —Si(OEt)O.sub.2/2 .sup.29Si-NMR 61.1 60.4 [mol %] Content of —SiO.sub.3/2 [mol %] .sup.29Si-NMR 12.3 15.5 Viscosity [MPas] s.a. 153 198 Mn [g/mol] GPC 1000 1087 Mw [g/mol] GPC 1100 1195

Materials Used

[0102] Fiber slurries (5% cellulose fibers 95% water): 90% of the fiber strands have a length of 1-6 mm and a diameter of 10-40 μm (+−5 μm). The fibers are present both individually and as bundles. The individual fiber strands are partly frayed further in some places.

[0103] Synthetic PP fibers: Diameter 18 μm (+−3 μm), length 6 mm (+−1 mm).

[0104] Lime: Nekafill® 15, Kalkfabrik Netstal AG; composition: 91.9% of CaCO.sub.3, 5.4% of MgCO.sub.3, sieve analysis residue (sieve 0.500 mm 0.0%, sieve 0.125 mm 1.9%, sieve 0.063 mm 18.7%).

[0105] Quartz flour: Amberger Kaolinwerke, Eduard Kick GmbH & Co. KG, type 16.900, dry sieve residue (DIN EN 933-10) 2% by weight >40 μm mesh opening.

[0106] Cement: Portland cement OPC type II-F (ASTM C150 (Standard Specification for Portland Cement)).

[0107] Filter paper: Whatman® Quantitative Filter Paper (Article No., 28414113 (US reference)), ashless, Grade 589/2 white ribbon, circles, diameter 90 mm, thickness 180 μm, pore size 4-12 μm, weight 85 g/m2.

Apparatus Used

[0108] Blade stirrer: IKA RW20

[0109] Pressing mold:

[0110] Ring (VA Steel): [0111] Internal diameter: 80 mm [0112] External diameter: 100 mm [0113] Height: 40 mm

[0114] Cylinder (Aluminum): [0115] Diameter: 79-80 mm [0116] Height: 60 mm [0117] Ring markings between height of 18 mm to 24 mm for visual assessment of the immersion depth.

[0118] Bottom Plate (VA Steel): [0119] Total diameter: 100 mm [0120] Total height: 30 mm [0121] Groove 10 mm×10 mm milled in from above. Groove accommodates ring.

[0122] Press: hydraulic cylinder press up to 180 bar max.

[0123] Air conditioned room: The room for conditioning of the test specimens has a temperature of 23° C. at 50% rel. atmospheric humidity.

[0124] Drying oven: UF 110 from Memmert.

Example C1 (not According to the Invention): Production of an Unautoclaved Fibrocement Sheet to which an Additive has not been Added

[0125] Water (2500 g), synthetic PP fibers (0.75 g), lime (7.5 g) and cement (39.25 g) are added in succession to a 5% strength fiber slurry (50 g) while stirring (1500 rpm, 15 minutes). The resulting mixture is subsequently stirred at 1500 rpm for 2 hours. The resulting mixture is filtered through a filter paper in a porcelain suction filtration funnel (diameter 10 cm) under a water pump vacuum.

[0126] The still moist residue is subsequently distributed in a metal pressing mold and pressed at 100 bar. The resulting fibrocement sheet is detached from the mold and subsequently stored for 2 weeks in an air conditioned chamber. The fibrocement sheet obtained has a density of 1.50 g/ml.

Example C2 (not According to the Invention): Production of an Unautoclaved Fibrocement Sheet to which Monomeric 1,4,4-Trimethylpentyltriethoxysilane has been Added as Additive

[0127] Water (2500 g), synthetic PP fibers (0.75 g), lime (7.5 g), cement (39.25 g) and 1,4,4-trimethylpentyltriethoxysilane (0.1 g) are added in succession to a 5% strength fiber slurry (50 g) while stirring (1500 rpm, 15 minutes). The resulting mixture is subsequently stirred at 1500 rpm for 2 hours. Further processing is carried out as described in Example 1. The fibrocement sheet obtained has a density of 1.51 g/ml.

Example C3 (not According to the Invention): Production of an Unautoclaved Fibrocement Sheet to which Monomeric n-Octyl-Triethoxysilane has been Added as Additive

[0128] The procedure of Example 2 is repeated, but the 0.1 g of 1,4,4-trimethylpentyltriethoxysilane is replaced by the same amount of n-octyltriethoxysilane. The fibrocement sheet obtained has a density of 1.45 g/ml.

Example 4 (According to the Invention): Production of an Unautoclaved Fibrocement Sheet to which Resin 1 has been Added as Additive

[0129] The procedure of Example 2 is repeated, but the 0.1 g of 1,4,4-trimethylpentyltriethoxysilane is replaced by the same amount of resin 1 from production example 1. The fibrocement sheet obtained has a density of 1.45 g/ml.

Example 5: Determination of the Water Absorption of Fibrocement Sheets

[0130] The fibrocement sheets obtained in Examples 1 to 4 are dried to constant mass at 40° C. for 24 hours in a drying oven. The water absorption is subsequently determined by means of storage in water under pressure in accordance with DIN EN 520. The results of these measurements are shown in Table 2.

TABLE-US-00002 TABLE 2 Example Example Example Example C1* C2* C3* 4 Water absorption 26.0 19.5 19.3* 1.9 after 2 h [% by weight] Reduction in the 25.0 25.8 92.9 water absorption after 2 h [%] Water absorption 27.8 23.1 23.0 4.3 after 24 h [% by weight] Reduction in the 16.9 17.3 84.5 water absorption after 24 h [%] *not according to the invention

Example C6 (not According to the Invention): Production of an Autoclaved Fibrocement Sheet to which an Additive has not been Added

[0131] Water (2500 g), cement (26 g) and quartz flour (20 g) are added in succession to a 5% strength fiber slurry (80 g) while stirring (1500 rpm, 15 minutes). The resulting mixture is subsequently stirred at 1500 rpm for 2 hours. The resulting mixture is filtered through filter paper in a porcelain suction filtration funnel (diameter 10 cm) under a water pump vacuum.

[0132] The still moist residue is subsequently distributed in a metal pressing mold and pressed at 170 bar. The resulting fibrocement sheet is detached from the mold and subsequently stored for 2 weeks in an air conditioned chamber. The fibrocement sheet is subsequently autoclaved (12 bar steam, 180° C., 6 h) and again stored for 2 weeks in an air conditioned chamber. The fibrocement sheet obtained has a density of 1.34 g/ml.

Example C7 (not According to the Invention): Production of an Autoclaved Fibrocement Sheet to which Monomeric 1,4,4-Trimethylpentyltriethoxysilane has been Added as Additive

[0133] Water (2500 g), cement (26 g), quartz flour (20 g) and 1,4,4-trimethylpentyltriethoxysilane (0.1 g) are added in succession to a 5% strength fiber slurry (80 g) while stirring (1500 rpm, 15 minutes). The resulting mixture is subsequently stirred at 1500 rpm for 2 hours. Further processing is carried out as described in Example 6. The fibrocement sheet obtained has a density of 1.38 g/ml.

Example C8 (not According to the Invention): Production of an Autoclaved Fibrocement Sheet to which Monomeric n-Octyl-Triethoxysilane has been Added as Additive

[0134] The procedure of Example 7 is repeated, but the 0.1 g of 1,4,4-trimethylpentyltriethoxysilane is replaced by the same amount of n-octyltriethoxysilane. The fibrocement sheet obtained has a density of 1.31 g/ml.

Example 9 (According to the Invention): Production of an Autoclaved Fibrocement Sheet to which Resin 1 has been Added as Additive

[0135] The procedure of Example 7 is repeated, but the 0.1 g of 1,4,4-trimethylpentyltriethoxysilane is replaced by the same amount of resin 1 from production example 1. The fibrocement sheet obtained has a density of 1.30 g/ml.

Example 10 (According to the Invention): Production of an Autoclaved Fibrocement Sheet to which Resin 2 has been Added as Additive

[0136] The procedure of Example 7 is repeated, but the 0.1 g of 1,4,4-trimethylpentyltriethoxysilane is replaced by the same amount of resin 2 from production example 2. The fibrocement sheet obtained has a density of 1.32 g/ml.

Example 5: Determination of the Water Absorption of Fibrocement Sheets

[0137] The fibrocement sheets obtained in Examples 6 to 10 are dried to constant mass at 40° C. for 24 hours in a drying oven. The water absorption is subsequently determined by means of storage in water under pressure in accordance with DIN EN 520. The results of these measurements are shown in Table 3.

TABLE-US-00003 TABLE 3 Exam- Exam- Exam- Exam- Exam- ple ple ple ple ple C6* C7* C8* 9 10 Water absorption 30.8 21.3 21.3 2.3 2.5 after 2 h [% by weight] Reduction in the 30.8 30.8 92.5 91.9 water absorption after 2 h [%] Water absorption 34.6 25.7 25.1 5.0 5.5 after 24 h [% by weight] Reduction in the 25.7 27.5 85.5 84.1 water absorption after 24 h [%] *not according to the invention