Use of polyurethane powder as inner additive of redispersible polymer powder

Abstract

A powdered polyurethane, preferably a powdered recycled polyurethane rigid foam is co-dried with a water insoluble film-forming polymer to obtain a redispersible polymer powder composite for use in hydraulic binders or cementitious compositions to improve performance of cementitious compositions or mortar, in applications such as cement based the adhesives (CBTA), or external thermal insulating composite systems (ETICS).

Claims

1. A water-redispersible polymer powder composite comprising a co-dried admixture of a water insoluble film-forming polymer, a colloidal stabilizer, and a powdered polyurethane foam, the amount of the powdered polyurethane foam being from 1% by weight to 99% by weight, based upon the total weight of the water-redispersible polymer powder composite, wherein the powdered polyurethane foam is a ground recycled rigid polyurethane foam having an average particle size of from 5 microns to 500 microns and the water-redispersible polymer powder composite has an average particle size of from 20 to 150 microns.

2. The water-redispersible polymer powder composite as claimed in claim 1 wherein the water insoluble film-forming polymer comprises a polymer prepared from a styrene and butadiene, a copolymer of styrene, butadiene and another comonomer, a vinylacetate ethylene (VAE) copolymer, a VAE/VA-VeoVA copolymer mixture, a polyurethane, a polyolefin, cellulose, a cellulose ether or a modified cellulose.

3. The water-redispersible polymer powder composite as claimed in claim 1 wherein the water insoluble film-forming polymer comprises a polymer prepared from styrene and butadiene, or a copolymer of styrene, butadiene and another monomer, or a vinylacetate-ethylene copolymer.

4. The water-redispersible polymer powder composite claimed in claim 1 wherein the amount of the powdered polyurethane foam is from 20% by weight to 70% by weight, based upon the total weight of the water-redispersible polymer powder composite.

5. A method for producing a water redispersible polymer powder composite comprising drying an aqueous mixture of a water insoluble film-forming polymer, a colloidal stabilizer, and a powdered polyurethane foam to obtain a water redispersible polymer powder composite, the amount of the powdered polyurethane foam being from 1% by weight to 99% by weight, based upon the total weight of the water-redispersible polymer powder composite, the powdered polyurethane foam being a ground recycled rigid polyurethane foam having an average particle size of from 5 microns to 500 microns, and the water-redispersible polymer powder composite having an average particle size from 20 to 150 microns.

6. The method for producing a water redispersible polymer powder composite as claimed in claim 5 wherein the water insoluble film-forming polymer comprises a polymer prepared from a styrene and butadiene, a copolymer of styrene, butadiene and another comonomer, a vinylacetate ethylene (VAE) copolymer, a VAE/VA-VeoVA copolymer mixture, a polyurethane, a polyolefin, a cellulose, or a cellulose derivative, the amount of the powdered polyurethane foam is from 20% by weight to 70% by weight, based upon the total weight of the water-redispersible polymer powder composite, and the powdered polyurethane foam has an average particle size of from 20 microns to 150 microns.

7. A dry mix composition comprising cement ingredients and the water redispersible polymer powder composite as claimed in claim 1 in an amount of at least 0.1% by weight, based upon the weight of the dry mix composition.

Description

EXAMPLE 1

(1) In this Example, two redispersible polymer powder composites containing recycled polyurethane rigid foam powder (RPU) in combination with two different styrene-butadiene water insoluble film-forming polymers (base polymers or latex) are evaluated in external cement based tile adhesives (CBTA) for quick open time, adhesion, workability, impact resistance, and water uptake. For one of the redispersible polymer composites, the styrene-butadiene water insoluble film-forming polymer has a comonomer content of 62 parts styrene, 35 parts butadiene, and 3 parts itaconic acid (a carboxylation of 3% by weight of itaconic acid, based upon the total comonomer weight), and a T.sub.g of 8 C. For the other redispersible polymer composite, the styrene-butadiene water insoluble film-forming polymer has a comonomer content of 51.6 parts styrene, 45.4 parts butadiene, and 3 parts itaconic acid (a carboxylation of 3% by weight of itaconic add, based upon the total comonomer weight), and a T.sub.g of 15 C. An SB RDP formulation without the recycled polyurethane rigid foam powder as an internal additive is also evaluated for comparison using the styrene-butadiene water insoluble film-forming polymer which has a comonomer content of 62 parts styrene, 35 parts butadiene, and 3 parts itaconic acid (a carboxylation of 3% by weight of itaconic acid, based upon the total comonomer weight), and a T.sub.g of 8 C.

(2) The redispersible polymer powder composites of the present invention may be produced by admixing: a) a water insoluble film forming carboxy laud styrene butadiene (SB) latex, and b) 20% by weight of a powdered recycled polyurethane rigid foam (MPU 300-2/300 having an X-50 particle size of 100 m and being treated with 3% by weight of silica), based upon the weight of the latex polymer. The mixture is prepared by admixing the powdered recycled polyurethane rigid foam with the latex dispersion, and stirring to obtain a homogeneous mixture.

(3) This mixture may be pumped to a two-fluid nozzle atomizer equipped on a NIRO mobile spray dryer. The air pressure to the nozzle may be 80 kg/hr of airflow, and the water evaporation may be 1 kg/hr. The spray drying may be conducted in an air environment with an inlet temperature fixed at 130 C., and the outlet temperature may be targeted to 50 C.1 C. by tuning the feed rate of the mixture. Concurrently, kaolin powder (KaMin HG 90) may be added into the chamber for spray drying as an anti-caking agent, with the amount being controlled to be 12% by weight of the dry powders.

(4) The comparative SB RDP formulation may be produced by pumping the water insoluble film forming carboxylated styrene butadiene (SB) latex to a two-fluid nozzle atomizer equipped on a NIRO mobile spray dryer. The air pressure to the nozzle may be 80 kg/hr of airflow, and the water evaporation may be 1 kg/hr. The spray drying may be conducted in an air environment with an inlet temperature fixed at 130 C., and the outlet temperature may be targeted to 50 C.1 C. by tuning the feed rate of the mixture. Concurrently, kaolin powder (KaMin HG 90) may be added into the chamber for spray drying as an anti-caking agent, with the amount being controlled to be 12% by weight of the dry powders. The formulations and the results of the evaluations are shown in Tables 1, 2, and 3, below:

(5) TABLE-US-00001 TABLE 1 Composition of Tested Samples A (RDP B C Sample Comparative) Composite Composite Base Polymer Styrene- Styrene- Styrene- butadiene with butadiene with butadiene with itaconic acid itaconic acid itaconic acid (62/35/3) (62/35/3) (51.6/45.4/3) Tg of Base Polymer 8 C. 8 C. 15 C. Powdered Recycled None 20% 20% Polyurethane Rigid Foam.sup.1, wt. % Anti-caking agent 12% 12% 12% (kaolin), weight % .sup.1X-50 particle size of 100 m treated with 3% by weight of silica (MPU 300-2/300).

(6) TABLE-US-00002 TABLE 2 Cement-based Dry Mortar Formulation RAW INGREDIENT Wt % Portland Cement Type 1 42.5 35.00 Quartz Sand F32 (Quarzwerke Frecheen) 31.60 Quartz Sand F36 (Quarzwerke Frecheen) 30.00 RPU -SB Composite or SB RDP of Samples A to C of Table 1 3.00 WALOCEL MKX40000 PF 01 hydroxyethyl methyl cellulose 0.40 (HEMC) Dow Wolff Cellulosics, Viscosity (2%) = 49390 mPA .Math. s Total Dry Mix 100.00

(7) TABLE-US-00003 TABLE 3 Results for Evaluation of Recycled PU Foam Powder in CBTA SAMPLE Property or Test A B C Base Polymer SB SB SB Tg +8 C. Tg +8 C. Tg 15 C. Powdered Recycled Polyurethane -none- 20% 20% Rigid Foam, (MPU 300-2/300), weight % Water demand 0.24 0.25 0.25 Tensile adhesion strength EN 1348 [N/mm.sup.2] 28 days nc (23/50) 0.83 1.07 0.94 Water storage 0.63 0.78 0.80 Warm storage 70 C. 0.77 0.79 0.67 Freeze-thaw exchange 0.64 0.89 0.91 Open time EN 1346 [N/mm.sup.2] 20 min. 0.54 0.85 0.70 30 min. 0.39 0.62 0.53 Quick Open Time CE 48.1 [%] 5 min. 100 100 100 10 min. 95 100 100 15 min. 90 95 95 20 min. 50 80 25 min. 35 50 50 30 min. 10 10 10 Workability 1-2 1 1 Setting with Vicat CE 94.1 minutes start 998 985 941 end 1223 1190 1128 duration 225 205 187

(8) The test methods employed in the evaluations are:

(9) Test Specification CE-48.1Determination of the Open Time of Tile Adhesives (Manual Stirring TestWetting Test)

(10) The purpose of this test is to determine the time span within which the back of a the can still be sufficiently wetted when laying the into a combed bed of tile adhesive. The principle is that tiles are laid into a combed bed of tile adhesive at 5 min. intervals and later removed. Subsequently the wetting of the rear of the is assessed.

(11) Setting TimeVicat (Dettki AVM-14-PNS)CE 94.1

(12) The mortar is mixed in accordance to EN-1348 after an appropriate maturing time. After mixing, the mortar is filled into the cup while being prodded lightly to prevent the presence of air voids. The sample is placed into the appropriate holder inside the penetrometer, the desired measuring program is selected and the test is started as described in the operating instructions. The penetrometer determines when setting begins (penetration depth: 36 mm) and when setting ends (penetration depth: 2 mm). The difference between the two times is the setting duration. If any measuring faults which might lead to false results are detectable on the graph, the time when setting begins and when it ends are to be corrected by interpolation,

(13) Determination of Open TimeEN 1346

(14) This European Standard specifies the test method for the determination of the open time of ceramic tile adhesives. The standard is applicable to all ceramic the adhesives for internal and external the installations on walls and floors. After a 28 days storage under standard conditions determination of the tensile adhesion strength of the adhesive is done by applying a force which increases at a constant rate of (25050) N/s. The open time in minutes, is the maximum time interval at which the adhesive meets the tensile adhesion strength requirement of 0.5 N/mm.sup.2 (EN 12004) (Table 5),

(15) Determination of Tensile Adhesives Strength for Cementitious AdhesivesEN 1348

(16) This European Standard specifies the test method for the determination of the tensile adhesion strength of cementitious ceramic tile adhesives. The standard is applicable to all ceramic the adhesives for internal and external tile installations on walls and floors. After a storage under different conditions determine the tensile adhesion strength of the adhesive by applying a force increasing at a constant rate of (25050) N/s. Storage conditions according EN 1348 are: a) standard storage: 28 d 23 C./50% relative humidity, b) water immersion: 7 d standard Climate storage/20 d water immersion/1 d standard climate storage, c) heat ageing: 14 d standard climate storage/14 d storage at 70 C./1 d standard climate storage was not analyzed, and d) freeze thaw cycles: 7 d standard storage/21 d water immersion/25 freeze-thaw cycles (cooling down to 15 C. within 2 h, storage at 15 C. for 2 h, water immersion for 2 h, repeat 25 times).

EXAMPLE 2

(17) In this Example, redispersible polymer powder composites containing two different recycled polyurethane flexible foam powders (MPU 200R and MPU 200R 3%) in combination with the two different styrene-butadiene water insoluble film-forming polymers (base polymers or latex) of Example 1 are evaluated in external cement based the adhesives (CBTA) for open time and adhesion as in Example 1. An SB RDP formulation without the recycled polyurethane rigid foam powder as an internal additive is also evaluated for comparison using the Example 1 styrene-butadiene water insoluble film-forming polymer which has a comonomer content of 62 parts styrene, 35 parts butadiene, and 3 parts itaconic acid (a carboxylation of 3% by weight of itaconic acid, based upon the total comonomer weight), and a Tg of 8 C. The recycled polyurethane flexible foam MPU 200R has an X-50 particle size of 80 to 120 m and is treated with 10% by weight of silica. The recycled polyurethane flexible foam MPU 200R 3% has an X-50 particle size of 100 m and is treated with 3% by weight of silica.

(18) The redispersible polymer powder composites of the present invention and the comparative SB RDP formulation may be produced as in Example 1. The cement based dry mortar formulation employed is the same as in Example 1, Table 2 except the 3% by weight of the RPU-SB Composite or SB RDP of the Samples A to C of Table 1 are replaced by 3% by weight of the RPU-SB Composite or SB RDP of the Samples 1-7 shown in Table 4. The formulations and the results of the evaluations are all shown in Table 4:

(19) TABLE-US-00004 TABLE 4 Results for Evaluation of Recycled PU Flexible Foam Powder in CBTA SAMPLE Formulation and Property or Test 1 2 3 4 5 6 7 (Comp.) Base Polymer Styrene-butadiene with itaconic acid 68 68 78 58 60 88 (62/35/3) Tg +8 C., weight % Base Polymer Styrene-butadiene with itaconic acid 68 (51.6/45.4/3) Tg 15 C., weight % Powdered Recycled Polyurethane Flexible Foam with 10% silica 20 10 30 20 20 none (MPU 200R), weight % Powdered Recycled Polyurethane Flexible Foam with 3% silica 20 none (MPU 200R 3%), weight % Anti-caking Agent Kaolin, weight % 12 12 12 12 12 12 Anti-caking agent MPU 200R (replaces Kaolin), weight % 20 Water demand 0.25 0.25 0.25 0.25 0.25 0.25 0.25 Tensile adhesion strength EN 1348 1500 g dry mortar, resting time 10 minutes [N/mm.sup.2] 6 days nc (23/50) 1.15 1.24 1.22 1.18 1.19 1.10 1.19 Open time EN 1346 [N/mm.sup.2] 20 6 days 20 min. 0.61 0.71 0.68 0.68 0.72 0.63 0.80 30 6 days 30 min. 0.47 0.60 0.60 0.54 0.66 0.49 0.58