Optimize Rheology in Construction Materials with Elementis BENAQUA® 5000

TAGS:  Epoxy Adhesives     Acrylic Adhesives    

This is a sponsored article by Elementis.

Do you know why flow control is critical in adhesive systems? Rheology modifiers provide stability, prevent settling, and extend the products' shelf life. They not only improve performance but also application behavior in adhesive systems.

Elementis rheological additives ensure better performance through sag control and ease of workability. Their exclusive product range falls under the following brand names:

• BENTONE®
• BENAQUA®

Moreover, these additives activate efficiently at lower temperatures, reducing production time.

The company contributes to sustainability by offering innovative rheology modifiers for water-based adhesives. They also use renewable materials in solvent-based adhesives.

Let's explore Elementis construction additives that can enhance the performance of your products.

Rheology Additives Prevent Tile Slippage and Sagging

A professional installer knows applying an overly stiff and sticky tile adhesive will cause discomfort and fatigue. Similarly, a homeowner tackling the application of tiles on a vertical bathroom wall may find it necessary to adjust the positioning of some tiles to maintain a straight line with appropriate spacing. In both cases, the need is to ease the application and to avoid the premature drying of the adhesive, a particularly significant issue in hot and dry climates.

After placing the tile in position, the aim is to prevent any slippage or sagging, so the tile remains precisely where it was carefully positioned. Likewise, skilled applicators want the same application ease and sag prevention for stucco or skim-coat products, once applied. These performance properties underscore the necessity for a high-quality rheology additive.


Rheology Additives Help in the Careful Positioning of Tiles to Avoid Slippage and Sagging
(Source: Elementis)
While constituting only a small fraction of an adhesive formulation, rheology additives play a crucial role in supporting the vast construction market and its potential. Within this market, two primary types of adhesive products exist:

• the epoxy (or urethane or acrylic) thermosetting-based resin systems
• the cementitious curing formulations

According to a recent MarketsandMarkets survey,* epoxy adhesives represent fully 70% of the industry's worldwide sales dollars for the finished product (*see graphs below). However, due to the high cost per unit compared to the lower cost of cementitious curing, epoxy formulations are less than 20% of product volume (See below Graph 3**).


*Graph 1: Market Size Breakdown in US Million Dollars and Expected Growth Rate
(Source: MarketsandMarkets)

*Graph 2: Market Size Breakdown in Kilotons and Expected Volume Growth Rate
(Source: MarketsandMarkets)
Elementis offers a range of additives catering to both thermosets/epoxy and cementitious types. This article focuses on the significantly larger volume requirements within the cementitious market segment. It's important to note that the anticipated growth rate for cementitious systems is expected to be considerably higher than thermosets.

Practical Applications — Tile and Stone Cement-based Adhesives

Tile and stone cement-based adhesives consist of binder, aggregate, additives, and water. These adhesives play a crucial role in affixing tiles to various substrates such as stone, concrete, brick, wood, and insulation panels. The diverse nature of substrates necessitates specific properties for application and effective adhesion.

Factors such as the type of application (wall, floor), location (interior, exterior), and substrate type influence adhesive performance. Achieving optimal adhesive qualities often involves a formulation emphasis on certain attributes, which may come at the expense of others.

The adhesive requirements differ based on three primary categories:

• residential,
• commercial, and
• institutional

**Graph 3: Market Size Breakdown by Type of Applicator
(Source: MarketsandMarkets)
Each category may demand a unique set of adhesive attributes, reflecting the specific needs and performance expectations associated with the respective environments.

Growth According to Market Trends

Tile and stone adhesives play a pivotal role in securely attaching ceramic tiles, natural stones, porcelain tiles, and mosaic glass to both floors and walls, among various other applications. Globally, floor tiles account for approximately 50% of tile adhesive consumption, with walls and other applications following suit.

Within the overall flooring market, ceramic tiles make up half of the share, encompassing vitrified, glazed, and porcelain varieties. The demand for ceramic tiles has experienced substantial growth due to their exceptional qualities, including high durability, resistance to thermal shock, and cost-effective maintenance.

One additive will not maximize all qualities for all these adhesive formulations. Elementis has a wide selection of additives and the formulating expertise to assist in creating a finished formulation to give the best combination of properties. Here is a list of well-known Elementis additives to control rheology:

Product	Description	% Active Matter
BENTONE® OC	Unrefined hectorite clay	40 - 60
BENTONE® CT	Unrefined hectorite clay	50
BENTONE® EW	Refined hectorite clay	100
BENTONE® DE	Refined hectorite clay Hyperdispersible	100
BENTONE® MA	Refined hectorite clay	100
BENTONE® LT	Organically modified refined hectorite	100
BENAQUA® 4000	Hectorite/polymer composite	100
BENTONE® DH	Organically modified hectorite	100

Elementis additives can overcome real and practical performance issues. This article will demonstrate the newest rheological additive, BENAQUA® 5000 for its excellent balance of properties. Explained below is how Elementis additives deliver several performance enhancements useful for tile adhesives, stucco, EIFS, grout, and flooring.

What are Elementis BENTONE® Rheological Additives?

Elementis mines and purifies the highest quality Hectorite-type clay. Hectorite has the structure of stacked platelets consisting of layers of metal oxides sandwiched between silicon oxide. The metal oxide interior creates a slight negative surface charge (with some sodium counter ion at each platelet surface). This charge is what gives dispersibility in water-based systems, unlike talc or some other clays which have no charge effect.


The Charge in the Metal Oxide Interior of Hectorite-type Clay Gives it Dispersibility in Water-based Systems
(Source: Elementis)

Exploring the mechanism

When introduced into an adhesive formulation, such as dry mortar or ready mix, the gaps between stacked platelets absorb water and undergo expansion. The platelets readily disperse when subjected to shearing forces, evenly distributing themselves within the mixture as individual platelets. This results in only a marginal increase in formulation viscosity during processes like mixing, pumping, or extrusion, where high shear forces are present.

However, once shearing ceases, the platelets swiftly align end-to-end, forming a structure akin to a "house of cards". This formation, in the absence of shear, establishes greatly higher viscosity, fulfilling the requirements for anti-settling and anti-sag properties.


Mechanism of Formation of House of Cards Structure of Platelets
(Source: Elementis)
Another crucial characteristic is referred to as hysteresis. The chart below illustrates that after shearing, resulting in low viscosity, there is a slight time delay before high viscosity is reinstated once shearing forces cease. This temporal aspect is significant for flow and leveling properties.


The Process of Hysteresis
(Source: Elementis)
An often-under-appreciated property of the BENTONE® products is that the house structure creates a yield point that is superior to using other rheology additives like fumed silica or cellulosic. The yield point is the amount of shear force at which a solid-like formulation begins to flow liquid-like. It is a critical factor for sag and settling control. The Elementis technical team can address this complicated effect on an application-by-application basis.

When developing a cementitious-based adhesive, the industry has established standards and tests to estimate real-world performance. For example, the TNCA Handbook for Ceramic, Glass, and Stone tile has an extensive appendix to outline the many test procedures and installation methods. ISO-Standard 13007-2 is for ceramic tile adhesives; Method 13007-4 is for grouts.

Which test/qualities are most important depends on the particular type and area of application. Elementis has now developed BENAQUA® 5000 which as part of an additive package can give excellent overall qualities and at a reduced cost relative to the top-performing product, BENAQUA® 4000.

Demonstration of some examples

A 1,000 g commercial-type powder tile adhesive containing a) 0.51% of a cellulose ether additive was compared to the same formula, but with b) 0.4% added cellulose ether + 0.27% BENAQUA® 5000. Both received 390 g water added, and Hobart mixed for 2 minutes.

The following table shows adequate flow table values, improved sag resistance with BENAQUA® 5000, much-improved yield point, and considerably better workability.

S. No.	Item Added by Weight %	Flow Table (cm)	Sag (mm)	Yield Point (Pascal)	Open Time for 50% Left on Tile (mins)	Cured Within (hrs)	Workability (Relative)
a)	0.51% cellulose ether	13.0	1	277	18	<24	sticky
b)	0.40% cellulose ether, + 0.27% BENAQUA® 5000	11.9	0	390	18	<24	Easy to apply, not sticky

Improved Sag Resistance, Much-improved Yield Point, and Considerably Better Workability with BENAQUA® 5000 for Commercial Powder Tile Adhesive

A 1,000 g commercial rapid set tile adhesive containing c) 0.51% cellulose ether additive was compared to d) 0.51% cellulose ether + 0.51% BENAQUA® 5000, e) 0.40% cellulose ether + 0.80% BENAQUA® 5000. All received 400 g of added water, Hobart mixed for 2 minutes.

The following table shows greatly improved sag resistance and better workability.

S. No	Item Added by Weight %	Flow Table (cm)	Sag (mm)	Open Time for 50% Left on the Tile (mins)	Cured Within (hours)	Workability
c)	0.51% cellulose ether	13.2	>50	24	4	Very sticky
d)	0.51% cellulose ether + 0.51% BENAQUA® 5000	11.0	2	18	4	Easy to apply, not sticky
e)	0.40% cellulose ether + 0.80% BENAQUA® 5000	11.2	3.5	18	4	Easy to apply, not sticky

Greatly Improved Sag Resistance and Better Workability with BENAQUA® 5000 for Commercial Rapid Set Tile Adhesive

A thin set mortar was prepared with f) 0.40% cellulose ether added, g) 0.25% cellulose ether + 0.17% BENAQUA® 5000 added, and h) 0.20% cellulose ether + 0.23% BENAQUA® 5000.

The following table shows improved yield points and far better sag resistance and workability.

S. No	Item Added by Weight %	Flow Table (cm)	Yield Point (Pascal)	Water Retention (%)	Open time for 50% Left on the Tile (mins)	Sag (mm)	Workability
f)	0.40% cellulose ether	12.3	344	99.3	21	38	Very sticky
g)	0.25% cellulose ether + 0.17% BENAQUA® 5000	12.4	391	99.2	18	0	Easy to apply, not sticky
h)	0.20% cellulose ether + 0.23% BENAQUA® 5000	12.6	415	99.3	18	0	Easy to apply, not sticky

Improved Yield Points and Far Better Sag Resistance and Workability with BENAQUA® 5000 for Thin Set Mortar

In all the instances retaining some cellulose is helpful for open time, but it is deficient for sag and the diagram below illustrates the workability advantage derived from BENAQUA® 5000.

The bentonite clay platelets contribute a slip/lubricating effect during the application of the adhesive, facilitating smoother troweling and reducing stickiness. However, once applied, the improved yield point prevents sag. The key takeaway is that by adjusting the ratio of the two additives, a formulator can optimize and enhance the desired set of application properties.


A quick recap of Elementis BENTONE® rheological additives is given below:

Product	Description	Form	Active Matter %	Typical Use Level %
Hectorite-based
BENTONE® OC	Unrefined natural hectorite clay, 40-60% active hectorite, calcium carbonate as gangue brownish color	Powder	40-60	0.05 - 4.0
BENTONE® CT	Unrefined natural hectorite clay, min. 50% active hectorite, calcium carbonate as gangue, white color	Powder	Min. 50	0.05 - 4.0
BENTONE® GS	Refined and beneficiated hectorite	Powder	100	0.05 - 3.0
BENTONE® LT	Organically modified refined hectorite	Powder	100	0.05 - 3.0
BENAQUA® 4000	Hectorite/polymer composite	Powder	100	0.05 - 3.0
BENAQUA® 5000	Hectorite/polymer composite	Powder	100	0.05 - 3.0

Rheological Additives for Construction Systems

Selection Chart Construction Systems	BENTONE® OC	BENTONE® CT	BENTONE® GS	BENTONE® LT	BENAQUA® 4000	BENAQUA® 5000	RHEOLATE® 1	RHEOLATE® 255
Renderings/Plasters/Stucco
Lime-cement	✓	x	x	-	✓	x	-	-
Gypsum	✓	x	x	-	✓	x	-	-
Emulsion (Synthetic)	-	✓	✓	-	x	✓	-	-
Flooring/Screeds/Underlayments
Gypsum Anhydrate-based	✓	x	x	-	-	-	-	-
Cement-based Grouts	✓	x	x	-	✓	-	-	-
Title Mortars/Adhesives
Emulsion-based (Pre-mix)	-	✓	✓	✓	✓	x	✓	-
Cement-based	✓	x	x	-	✓	x	-	-
Emulsion/Cement	x	-	-	-	✓	x	-	-
Emulsion-based EIFS Mortars/Adhesives	-	-	-	-	-	-	-	-
Pasty Systems (Pre-mix)	-	✓	✓	-	✓	✓	x	x
Powdered Systems	-	✓	✓	-	✓	-	-	-
Asphalt Systems
Sealers	✓	-	✓	-	-	✓	✓	-
Road Repair (Pourable/ Brushable)	-	-	-	-	-	-	✓	✓
✓: Best Choice; x: Alternative; -: Not applicable

Selection Chart Construction Systems for Rheology Additives

Summary

In today's market, customers increasingly seek efficient applications and enhanced sag resistance for the expanding cementitious tile mortar market. Rheological additives play a crucial role in tile adhesive formulations.

Elementis offers a variety of additives to cater to different needs. The composition and functioning of these additives are detailed and explained. Notably, the specific BENTONE® variant, BENAQUA® 5000, demonstrates performance optimization, as seen by the test data presented above.

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