WO2013078675A1

WO2013078675A1 - Rubber powder modified tile grout

Info

Publication number: WO2013078675A1
Application number: PCT/CN2011/083369
Authority: WO
Inventors: Zhiliang Zhang
Original assignee: Dow Global Technologies Llc
Priority date: 2011-12-02
Filing date: 2011-12-02
Publication date: 2013-06-06

Abstract

A tile grout containing 15%-35% by weight of cement, 40%-65% by weight of coarse aggregates, 2%-20% by weight of rubber powder, 1%-6% by weight of polymer particles selected from a group consisting of redispersible polymer powders and/or dispersed polymer particles in a polymer emulsion, and 5%-25% by weight of fine fillers, with percentages based on total dry weight of said tile grout.

Description

RUBBER POWDER MODIFIED TILE GROUT

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a mortar composition used in construction industry.

Particularly, the present invention relates to a tile grout applicable for EIFS construction withstanding deformation of EIFS.

Introduction

In construction field, tiles can bring better decorative effect and at the same time have better weather resistance and durability than coatings, and therefore they are widely used as a decorative layer on an exterior wall.

Exterior Insulation Finish System (EIFS) is an exterior wall cladding system, and is also known as External Thermal Insulation Systems (ETICS) in Europe. It can be used on both residential and commercial buildings for the purpose of saving energy, improving room comfort and protecting walls against moisture and other external elements.

EIFS normally comprises a thermal insulation layer, polymer mortar layers, and a finish layer. The finish layer is the decorative layer and is the outmost layer of the system.

The thermal insulation layer consists of polymer boards, such as EPS (expanded polystyrene) or XPS (extruded polystyrene) boards. The polymer boards may experience more deformation upon outer impact and temperature changes than other thermal insulation layers, such as those made of hollow microspheres and mortar. Therefore higher flexibility is required for the whole EIFS system including the finish layer when using polymer boards.

A tile grout is used to seal the gaps between tiles. A traditional tile grout, such as those disclosed in CNl 145391 A and CN101643346A, normally consists of cement, sand, polymer, some additives and water. These traditional tile grouts do not have enough flexibility to withstand the deformation that can occur in an EIFS and therefore are not suitable for use in the finish layer of EIFS.

CN101323514A teaches a mortar comprising rubber powders as aggregates and the mortar can be used as a basecoat mortar in EIFS. But the mortar cannot meet the

requirement of flexural strength regarding a tile grout under Chinese Industrial Code

JC/T1004-2006. It is desirable to develop an EIFS -applicable tile grout which keeps acceptable flexibility even after freeze-thawing cycles.

BRIEF SUMMARY OF THE INVENTION

Surprisingly, inventors have found a tile grout that maintains workable flexibility as required for EIFS applications after a weathering test including freeze-thawing circulation. Thus, such tile grout can be used in construction to prepare the decorative layer on an exterior wall, such as the finish layer of EIFS, under Chinese Industrial Code JC/T 1004-2006.

Discovery of the present invention is partly a result of recognizing that current tile grouts comprise only rigid inorganic particles, such as silica sand. Such particles form a stiff phase and can bear little deformation against stress resulting from outer impact and temperature changes. Surprisingly, the inventors of the present invention discovered that by addition of rubber powder as flexible aggregates, the inventive tile grout can absorb some stress and therefore lower the stiffness and reduce the risk of crack.

The present invention provides a tile grout comprising 15 percent (%)-30% by weight of cement, 40%-65% by weight of coarse aggregates, 2%-20% by weight of rubber powder, l%-6% by weight of polymer particles selected from a group consisting of redispersible polymer powders and dispersed polymer particles in a polymer emulsion, and 5%-25% by weight of fine fillers, with percentages based on total dry weight of said tile grout.

Preferably, the inventive tile grout comprises 20%-26% by weight of Portland cement, 45%-55% by weight of silica sand, 3%-8% by weight of rubber powder, 3%-5% by weight of redispersible polymer powder of ethylene vinyl acetate, 8%-18% by weight of calcium carbonate, 0.2%-0.5% by weight of calcium formate, 0.02%- 0.1% by weight of methyl hydro xyethyl cellulose, and 0.1%-0.5 by weight of silane based hydrophobic agent, with percentages based on total dry weight of said tile grout.

The tile grout composition of the present invention is useful for preparing a ceramic finish layer in EIFS. A ceramic finish layer prepared from the inventive tile grout meets the EIFS requirements including the bending strength requirement under Chinese Industrial Code JC/T 1004-2006, "Grouts for Ceramic Wall and Floor Tiles", and transverse deformation under Shanghai Local Code DB31-T-366-2006 and Beijing Local Code DB11/T584-2008. DETAILED DESCRIPTION OF THE INVENTION As used herein:

Unless otherwise stated, all percentages (%) are by weight based on the total dry weight of the tile grout. The descriptions of the various ingredients set forth below are non- limiting.

The units/abbreviations used in the description are illustrated as follows.

Unit Full name

m meter

m² square meter

mm millimeter

MPa Mega Pascal

s second

min minute

mPa-s(i.e. centipoise, cp) milli-Pascal- second

Rubber powder are rubber particles obtained by processing, such as by cutting and/or grinding rubbers blocks or strips into fine particles. Preferably, the rubber particles have a size of less than 0.5mm. There is no limitation on the shape of the particles and for example, they can be amorphous. The rubber can be selected from any natural rubbers and synthesized rubbers. Most often, the rubber powder can be obtained from recycled waste tires by cutting and grinding processes. A typical process for preparing rubber powders can be found at http://en.518ad.com/Selling/SellDetails.aspx?ID=200902251138419191, which is provided by Jiangsu Shijitianyuan Import & Export Co., Ltd. The process is described below. Inner steel rings of waste tires are cut off by a cutter. Tires are then crushed into rubber blocks of 500mm or so by the cutter. Crushed blocks are sent back to the crushing room through a filter system for re-crushing. Rubber blocks are filtered through round wire mesh. Filtrated rubber blocks are smashed into rubber granules with size from 5 to 10 mesh (1.7mm-4mm). Steel wire is separated, such as by a magnetic selector, from the rubber grains under normal temperature. The 5 to 10 mesh rubber granules are ground into rubber powder particles having an average size of 40-120 mesh (0.12mm-0.4mm) .

The waste tires can be any kind of rubber including natural rubbers and synthesized rubbers. Preferably, the rubber powders have a size of less than 0.5mm and are obtained from styrene-butadiene rubber and/or ethylene-propylene-diene monomer rubber, such as the Junwei rubber powder available from Shanghai Junwei Rubber And Plastics Products Co., Ltd.

The inventive tile grout typically comprises 2% or more, and can comprise 2.5% or more, even 3% or more, even 3.5% or more, and at the same time typically comprises 20% or less, and can comprise 10% or less, even 8% or less, even 6% or less by weight of rubber powder based on the total dry weight of the tile grout.

Redispersible polymer powder (RDP) is mainly a powdery polymer and is typically made by spray drying emulsion into polymer particles in the presence of various additives such as a protective colloid and anti-caking agent. When mixed with water, these polymer powders can be re-dispersed to form an emulsion and such polymer can be called emulsion polymer. Upon mixing with cement mortar, the RDP can be dehydrated to form continuous films within cement mortar later. RDP can bring modified properties to the mortar.

The RDP can comprise any one or combination of more than one of the following monomers polymerized into the RDP: vinyl esters, methacrylic or acrylic esters, vinyl aromatics, vinyl halides and olefins or dienes. Preferred vinyl esters comprise vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, vinyl laurate, 1-methylvinyl acetate, vinyl pivalate, and vinyl esters of alpha-branched monocarboxylic acids having from 5 to 11 carbon atoms. Some preferred examples include VEOVA™ 5 RTM, VEOVA™ 9 RTM, VEOVA™ 10 RTM, VEOVA™ 11 RTM (VEOVA is a trademark of Resolution

Performance Products, LLC). Preferred methacrylic esters and acrylic esters include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, n-butyl acrylate, n-butyl methacrylate, and 2-ethylhexyl acrylate. Preferred vinyl-aromatics include styrene, methylstyrene, and vinyltoluene. A preferred vinyl halide is vinyl chloride. The preferred olefins are ethylene and propylene, and the preferred dienes are 1,3-butadiene and isoprene.

More preferably, the RDP comprises one or more polymer selected from a group consisting of vinyl ester-ethylene copolymer including ethylene vinyl acetate (EVA), such as Elotex FX2350 available from AkzoNobel, vinylacetate/vinyl-versatate copolymer and styrene/acrylic esters copolymer.

Suitable polymer emulsions include two-phase systems having finely dispersed polymer particles in solvent such as water. Such polymer particles can comprise the emulsion polymers contained in RDP as defined above. The dispersed polymer particles normally comprise emulsion polymer particles, such as vinyl polymer or polyacrylic ester copolymer particles, and a surfactant containing hydrophobic and hydrophilic moieties. The preferred aqueous emulsion polymer, when applied as a coating on a substrate and cured at ambient or elevated temperature, has been found to have excellent solvent, chemical and water resistance; exterior durability; impact resistance; abrasion resistance; excellent adhesion to a variety of substrates.

The inventive tile grout typically comprises 1% or more, and can comprise 2% or more, even 3% or more, even 3.5% or more, and at the same time typically comprises 6% or less, and can comprise 5% or less, even 4.5% or less by weight of polymer particles selected from a group consisting of redispersible polymer powders and dispersed polymer particles in a polymer emulsion based on the total dry weight of the tile grout.

Fillers are inorganic material without binding function in mortar and they can be adhered to each other with a binder, such as cement. They include coarse aggregates and fine fillers. The particle size of coarse aggregates is larger than 0.075mm and with a maximum size up to 8mm. One example of coarse aggregates is silica sand (quartz sand).

Quartz sand generally refers to all sorts of sand including natural sand and manufactured sand with a quartz content of at least 90% by weight. Natural sand is widely used in construction industry, such as sea sand, fluvial sand and lake sand. Preferably the shea sand used in the inventive tile grout are the natural sand and manufactured sand having a size of

0.075mm-4.75mm under Chinese National Code GB/T 14684-2001, "Sand for Building".

The particle size of fine fillers is less than 0.075mm. Examples of fine fillers include calcium carbonate (CaCOs) powder, silica fume, slag powder and fly ash having a grade II and F type under Chinese National Code GB 1596-2005. Preferably the fine fillers are calcium carbonate having a size of less than 0.075mm. The particle size can be measured by air jet sieve, referring to Appendix A of Chinese National Code GB/T1596-2005, "Fly Ash

Used for Cement and Concrete".

The inventive tile grout typically comprises 40% or more, and can comprise 45% or more, even 50% or more, and at the same time typically comprises 65% or less, and can comprise 60% or less, even 55% or less by weight of coarse aggregates based on the total dry weight of the tile grout. The inventive tile grout typically comprises 5% or more, and can comprise 6% or more, even 8% or more, and at the same time typically comprises 25% or less, and can comprise 20% or less, even 18% or less by weight of fine fillers based on the total dry weight of the tile grout.

Cement is a hydraulic binder widely used in construction industry. The cement used in the inventive tile grout can be selected from Portland cement, aluminate cement, and sulfate aluminate cement. Preferably, the cement is Portland cement. More preferably, the cement is Portland cement having a strength grade of 42.5,42.5R, 52.5, or 52.5R according to China National Code GB 175-2007, "Common Portland Cement".

The inventive tile grout typically comprises 15% or more, and can comprise 18% or more, even 20% or more, and at the same time typically comprises 35% or less, and can comprise 30% or less, even 26% or less by weight of cement based on the total dry weight of the tile grout.

Early strength agent, also named "accelerator", means a chemical substance mixed with cement slurry to reduce the time required for setting and hardening cement to develop sufficient compressive strength to enable demolding or drilling operations to continue. The early strength agent can be selected from nitrate salts (such as sodium nitrate and potassium nitrate); formate salts (such as sodium formate and calcium formate); chloride salts (such as sodium chloride, calcium chloride, and magnesium chloride); thiocyanate salts (such as sodium thiocyanate); nitrite salts (such as sodium nitrite); mono-, di- and triethanolamine; and highly alkaline agents including alkali hydroxide (such as sodium hydroxide, calcium hydroxide, and potassium hydroxide), alkali carbonate (such as sodium carbonate and potassium carbonate), alkali silicate (such as sodium silicate), and alkali aluminate (such as sodium aluminate).

Preferably, the early strength agent used in the inventive tile grout is lithium carbonate or calcium formate.

The inventive tile grout typically comprises 0.1% or more, and can comprise 0.2% or more, even 0.3% or more, and at the same time typically comprises 0.6% or less, and can comprise 0.5% or less, even 0.4% or less by weight of early strength agent based on the total dry weight of the tile grout.

Hydrophobic agent is water repellant material incorporated into hydratable cementitious materials such as cement pastes, masonry cements, mortars, and concrete to achieve a degree of moisture impermeability. Exemplary hydrophobic agents suitable for the inventive tile grout include an aliphatic carboxylic acid or salt or ester thereof, a fatty acid or salt or the ester thereof, a natural or synthetic wax, a natural or synthetic oil, a silicone compound, a silane compound, a siloxane compound, a naphthalene compound, a melamine compound, a dicarboxylic acid or the salt thereof, or a mixture of any of the foregoing.

Preferably hydrophobic agents are silane-based. Silane-based hydrophobic agents are silanes that are chemical compounds of silicon and hydrogen and consist of a chain of silicon atoms covalently bonded to each other and to hydrogen atoms. Alkyl groups could be linked to the silicon chain of a siliane-based hydrophobic agent. For example, butyltrimethoxysilane and other silanes are commercially available from Dow Corning and AkzoNobel and are suitable silane-based hydrophobic agents.

The inventive tile grout typically comprises 0.05% or more, and can comprise

0.075% or more, even 0.1% or more, and at the same time typically comprises 0.7% or less, and can comprise 0.5% or less, even 0.3% or less by weight of hydrophobic agent based on the total dry weight of the tile grout.

Cellulose ether is a commonly used additive in a mortar composition as a rheology modifier. It is found that the main benefits brought include improved workability and water retention. Suitable cellulose ethers used in the inventive tile grout include

hydro xyalkylcelluloses (e.g., hydro xyethylcellulose (HEC), hydro xypropylcellulose (HPC) and hydroxypropylhydroxyethylcellulose (HPHEC)), carboxy-alkylcelluloses (e.g., carboxymethylcellulose (CMC)), carboxyalkylhydroxyalkylcelluloses (e.g.,

carboxymethylhydroxyethylcellulo se (CMHEC) , carboxymethyl-hydroxypropylcellulo se (CMHPC)), sulphoalkylcelluloses (e.g., sulphoethylcellulose (SEC), sulphopropylcellulose (SPC)), carboxyalkylsulphoalkylcelluloses (e.g., carboxymethylsulphoethylcellulose

(CMSEC), carboxymethylsulphopropylcellulose (CMSPC)),

hydroxyalkylsulphoalkylcelluloses (e.g., hydroxyethylsulphoethylcellulose (HESEC), hydro xypropylsulphoethylcellulose (HPSEC) and hydro xyethylhyd

roxypropylsulphoethylcellulose (HEHPSEC)), alkylhydroxyalkylsulphoalkylcelluloses (e.g., methylhydroxyethylsulphoethylcellulo se (MHESEC) ,

methylhydroxypropylsulphoethylcellulose (MHPSEC) and

methylhydroxyethylhydroxypropylsulphoethylcellulose (MHEHPSEC)), alkylcelluloses (e.g., methylcellulose (MC), ethylcellulose (EC)), binary or ternary alkylhydroxyalkylcellulose (e.g., hydro xyethylmethylcellulose (HEMC), ethylhydroxyethylcellulose (EHEC), hydro xypropylmethylcellulose (HPMC), ethylhydroxypropylcellulose (EHPC),

ethylmethylhydroxyethylcellulose (EMHEC), and ethylmethylhydroxypropylcellulose (EMHPC)), alkenylcelluloses and ionic and nonionic alkenylcellulose mixed ethers (e.g., allylcellulose, allylmethylcellulose, allylethylcellulose and carboxy-methylallylcellulose)), dialkylaminoalkylcelluloses (e.g., N,N-dimethylaminoethylcellulose, N,N- diethylaminoethylcellulose), dialkylaminoalkylhydroxyalkylcelluloses (e.g., N,N- dimethylaminoethylhydroxyethylcellulose and N,N- dimethylaminoethylhydroxypropylcellulose), and aryl-, arylalkyl- and

arylhydroxyalkylcelluloses (e.g., benzylcellulose, methylbenzylcellulose and

benzylhydroxyethylcellulo se) .

Preferably, the cellulose ether used in the inventive tile grout is methyl hydro xyethyl cellulose, such as WALOCEL™ MKX6000 PF01 and MKX60000 PF01 available from The Dow Chemical Company (WALOCEL is a trademark of The Dow Chemical Company).

The inventive tile grout typically comprises 0.02% or more, and can comprise 0.03% or more, even 0.05% or more, and at the same time typically comprises 0.2% or less, and can comprise 0.1% or less, even 0.08% or less by weight of cellulose ether based on the total dry weight of the tile grout. Test Method

Flexural strength test including testing apparatus and equipment, sample preparation and curing, and freeze-thaw circulation are conducted under Chinese Construction Industry Code JC/T 1004-2006, "Grout for Ceramic Wall and Floor Tiles". Transverse deformation testing processes also follow JC/T 1004-2006. Since the requirement of transverse deformation is not identified in JC/ T 1004-2006, qualified transverse deformation value refers to Shanghai Local Code DB31/T 366-2006, "Technology Requirement of Special Mortars for External Thermal Insulation", and Beijing Local Code DB11/T584-2008, "Technical Specification for External Thermal Insulation on Outer-walls".

EXAMPLE A comparison test was designed and conducted for testing the flexural strength and transverse deformation of sample tile grouts made from an inventive formulation (Inventive sample) and a traditional formulation (Comparative sample).

Raw materials used in the comparison test are listed in Table 1 as below.

Table 1 : Raw materials used in comparison test

Conch is a trademark of Linking Composite Material (Suzhou) Co., Ltd.

Junwei is a trademark of Shanghai Junwei Rubber and Plastics Products Co., Ltd. WALOCEL is a trademarks of The Dow Chemical Company.

LANXESS is a trademark of LANXESS AG.

Elotex is is a trademark of AkzoNobel Specialty Chemicals Co. Ltd. The components of Inventive sample and Comparative sample and test results are listed in Table 2 as below.

Table 2: Formulations and test results of Comparative sample and Inventive sample (unless otherwise indicated, values are in units of wt. relative to total dry weight of a tile grout.)

Under JC/T 1004-2006, the flexural strength at 28 day and after freeze-thaw circulation should be at least 2.5MPa. Both Inventive sample and Comparative sample meet the requirement. But Inventive sample has lower flexural strength than Comparative sample, which means that the flexibility of Inventive example is higher than Comparative sample. Under Shanghai Local Code DB31/T 366-2006 and Beijing Local Code DB11/T584-2008, the transverse deformation should be at least 2.0mm. Inventive sample meets such requirement but Comparative sample does not meet.

It can be seen that the inventive tile grout meets the requirements of both flexural strength and transverse deformation and at the same time has a higher flexibility than a traditional tile grout.

Claims

1. A tile grout comprising

(a) 15%-35% by weight of cement,

(b) 40 -65 by weight of coarse aggregates,

(c) 2 -20 by weight of rubber powder,

(d) l -6 by weight of polymer particles selected from a group consisting of redispersible polymer powders and dispersed polymer particles in a polymer emulsion , and

(e) 5 -25 by weight of fine fillers,

with percentages based on total dry weight of said tile grout.

2. The tile grout of Claim 1, wherein said rubber powders comprise powders selected from a group consisting of styrene-butadiene rubber powders and ethylene-propylene-diene monomer rubber powders.

3. The tile grout of Claim 1, wherein said rubber powders have a size of less than

0.5mm.

4. The tile grout of Claim 1, wherein said fine fillers are calcium carbonate.

5. The tile grout of Claim 1, wherein said polymer particles of said redispersible polymer powder or said polymer emulsion comprise ethylene- vinyl acetate copolymer.

6. The tile grout of Claim 1, said tile grout further comprising early strength agent, hydrophobic agent and cellulose ether.

7. The tile grout of Claim 6, wherein said early strength agent is lithium carbonate and calcium formate.

8. The tile grout of Claim 6, wherein said hydrophobic agent is silane based powder.

9. The tile grout of Claim 6, wherein said cellulose ether is selected from methyl cellulose, carboxymethyl cellulose and methyl hydroxyethyl cellulose.

10. The tile grout of Claim 1, said tile grout comprising

(a) 20%-26% by weight of Portland cement,

(b) 45%-55% by weight of silica sand,

(c) 3%-8% by weight of rubber powder,

(d) 3%-5% by weight of redispersible polymer powder of ethylene vinyl acetate,

(e) 8%-18% by weight of calcium carbonate,

(f) 0.2%-0.5% by weight of calcium formate,

(g) 0.02%- 0.1% by weight of methyl hydro xyethyl cellulose, and

(h) 0.1%-0.5 by weight of silane based hydrophobic agent,

with percentages based on total dry weight of said tile grout.