This file has been designed to help you to find information about Laponite® products quickly and easily. Click on the links or questions in the tables below to allow you to move around the page. For any technical support requirement, or if you cannot find what you are looking for on this page, please e-mail our Technical team at: help@laponite.com

Select from the following categories

1. Do I need to use high shear to disperse Laponite®?
High shear mixing is not required to disperse Laponite®; however, high shear mixing will not damage Laponite®, as is the case for some polymeric thickeners. A high-speed mixer is often recommended, especially when making high solids concentration dispersions of Laponite® sol grades.

2. Does high shear damage Laponite®? No. High shear mixing will not damage Laponite®, as is the case for some polymeric thickeners

3. Do I need to neutralise Laponite® to make it gel? No. Laponite® will disperse into water with stirring. Gel formation occurs as a result of interactions between the Laponite® and the components in a formulation.

4. Has Laponite® ever been tested on animals? At the time of writing, in 2006, the last time that Laponite® products were tested on animals was over 23 years ago. Laponite® products were tested on animals several times during the period between 1969 and March 1983. It is Rockwood’s firm intention not to carry out animal testing on Laponite® in the future, but to use in vitro and human testing procedures.

5. What would happen if I ate some Laponite®? Our first and strong recommendation would be to seek professional medical advice immediately. Rinse the mouth thoroughly and drink plenty of water. Show your medical officer technical literature relating to Laponite® products. Safety Data Sheets can be downloaded from www.laponite.com. From the home page, click on the Technical Information button, select MSDS from the list that opens and then click on the Laponite® grade.

Laponite® products are classed as Low Acute Toxicity (LD50 oral rat > 8g/ kg body weight), but may cause gastric irritation.

6. What chemicals are used to convert a gel forming grade, e.g. Laponite® B to a sol forming grade, e.g. Laponite® JS? Tetra-sodium pyrophosphate- trade name, tetron and often referred to as TSPP, is the dispersant added to Laponite® in order to produce “temporary sol grades”. This salt is milled to approximately the same particle size as the Laponite® powder in order to improve physical stability of the blended powders on storage. The large negatively charged pyrophosphate anion that is produced when TSPP dissolves, acts to neutralise the positive charges on the edge of the Laponite® crystal. This mechanism prevents the Laponite® sol grade from forming a gel in water only.

The additive used in “permanent sol grades” Laponite® S482 and Laponite® SL25 is a proprietary substance. For an explanation of the differences between temporary and permanent sol grades, click…here… What’s a sol grade?

Effect of electrolyte concentration upon Gel Strength of Laponite® at 2% concentration in water

Following on from this, Laponite® can be used efficiently in formulated products that are based upon deionised water, as the other components of the formulation will automatically provide the electrolytes that trigger gel formation. In practical terms, a clear gel of Laponite® RD in water of low electrolyte content can be useful as a simple model for demonstrating the unique properties that can be imparted when using the product as rheological additive in water based formulated products.

The effects of electrolyte upon Laponite® are described in detail on pages 18 to 20 of the Laponite® Technical Brochure, “Laponite® performance additives”. This can be downloaded as a pdf file from the following web link: http://www.laponite.com/pdfs/laponite.pdf

It should be noted that some hard tap water sources may contain too much dissolved solids to allow gel formation to occur. This can be overcome by use of a sol grade, e.g. Laponite® RDS, or by using Laponite® RD in combination with a sequestering agent (a water-softener) as detailed in [Click here] I’ve got hard water and want to make clear gels of Laponite® in water. Is there an additive that I can use to treat my water source?

In many types of formulas, Laponite® is actually used in combination with thickeners, such as gums or polymers. This can have significant benefits, such as a synergistic increase in viscosity build or an increase in tolerance to higher levels of surfactants or salts. It is also a useful technique for…”rheological engineering”…i.e. taking different aspects from the rheology of two or more thickeners to design a precise rheological profile for a certain application.

by e-mail: help@laponite.com

The proven additive for hard water as far as Laponite® and clear gels is concerned is tetra-sodium pyrophosphate, the additive that is used to convert Laponite® into sol forming grades. TSPP will produce insoluble Ca & Mg salts with colloidal particle-size…i.e. the insoluble particles are very small and do not cause haziness. The problem with TSPP is that it is also a dispersant for Laponite® RD and if added in excess it may cause sol formation or reduction in gel strength. Because of this, it is essential to just add the right amount of polyphosphate to get rid of most of the hardness, but avoid having too much so that gel strength is affected.

To deal with the problem…is it possible to get a typical water analysis? Your water supply company can sometimes give this. If we know the level of water hardness, then we can make a calculation to estimate the amount of softening salt to add in order to remove the Ca & Mg that is causing Laponite® to be hazy. With this information, we do a calculation to suggest the required softener addition level using the same chemical equation that we use to show how Laponite® sol grades can be activated…

Na₄P₂O₇ (aq) + 2CaCO₃= Ca₂P₂O7 (s) + 2Na₂CO₃ 

A complicating factor in this is that water hardness is often expressed in different ways in different regions; use the table below to estimate the TSPP addition level that will be required for your own water source.

12. Are there technical literature or information resources available on Laponite® in languages other than English? The Laponite® Technical Brochure, “Laponite- performance additives” is also available in French, German and Japanese. French and German versions of this brochure are reproduced on the Laponite® Technical CD-ROM. A further information resource is our worldwide network of distributors. The contact details of your local or regional distributor for Laponite® products can be found on the following web link… http://www.scprod.com/distributor_contact.asp

13. In which decade were Laponite® products first sold commercially? 1960’s

14. In what year were Laponite® products last tested on animals? 1983

15. What phrase best describes the rheology of a Laponite® gel? Highly shear thinning and thixotropic.

We consistently recommend that Laponite® products should always be premixed in water before use.

17. Is there an organo- version of Laponite®? It is possible to make organo-modified versions of Laponite® products; these are mainly used for research and development purposes. Commercial organo-Laponite® products are not manufactured at the present time.

18. What are the CAS/ Einecs numbers/ INCI names for Laponite® products?

A summary of the regulatory status of Laponite® products is given in the table below.

19. What is the German Water Hazard Classification for Laponite®? The German Water Hazard Classification is WGK 1- for all Laponite® grades.

20. What is the INCI name for Laponite® XL21? The INCI name for XL21 is sodium magnesium fluorosilicate.

21. Can I use Laponite® to make skincare formulas at natural skin pH? Yes, it is possible to make skin care formulas containing Laponite® in the pH range 5 to 6. Rockwood has developed Laponite® products and starting formulations that allow the preparation of a wide range of different types of leave-on and rinse-off skin care products, such as facial moisturisers, anti-ageing creams, hand and body lotions, sun care, baby care, skin and hair wash etc. For more information, send an e-mail to help@laponite.com and ask for Laponite® Technical Bulletin L465, “New developments with Laponite® in Personal care”. This bulletin can also be downloaded at the following web link: http://www.laponite.com/application_bulletins.asp

22. Why have I got gel seeds in my paint containing Laponite®? This problem could have been caused by one of several reasons. If the suggestions below do not resolve the problem, please contact us on help@laponite.com for assistance.

23. What’s the difference between RD/ XLG and RDS/XLS? Laponite® RD & RDS are designed for use in industrial applications. Laponite® XLG and XLS are designed for use in skin contact applications. In chemical terms, RD and XLG are the same as each other, as are RDS and XLS. The significant difference is that products that are designated “XL” are manufactured on a dedicated manufacturing stream, designed for making products suitable for supply to the personal care industry. This ensures that “XL” products have minimum bacteriological content, very low heavy metal content and are free from contamination with foreign material

24. Which CMC type gives best synergy with Laponite®? Using Laponite® in combination with CMC can produce large synergistic increases in viscosity development. A higher level of synergy is seen with medium and high viscosity CMC grades.

No. In fact, in some cases, it can be difficult to incorporate Laponite® into a formula after if has become a gel. For example, if a Laponite® pre-gel is combined with a low viscosity liquid, such as an emulsion resin, it can be difficult to get a homogenous mixture without very efficient or high shear mixing. Observing “gel-seeds” in the formulation will often be a manifestation of this problem. For suggestions on how to avoid this problem, click on: Why have I got gel seeds in my paint containing Laponite®?

27. Can I thicken acidic products using Laponite®? Yes, with care. Laponite® is a mildly alkaline material and is easiest to formulate at neutral pH and the basic side of the pH range. However, when handled correctly, it can be used to produce thixotropic rheology in, for example, skin creams at pH 5.5, surface coatings at pH 3 and mineral acid based toilet cleaners at pH<1. Guideline starting formulations are available on our web site www.laponite.com or request them directly from Rockwood by e-mail to help@laponite.com

28. What is the highest level of conductivity/resistivity that you can expect to obtain when making an antistatic coating on paper using Laponite®? At a coat weight of 3 g/m-2, of Laponite® JS, with, e.g. an acrylic or SBR binder (100 parts Laponite® to 10-20 parts dry mass of binder), it is possible to obtain a surface conductivity/ resistivity of 10⁶ohms.cm^-2

29. What is the usual delivery form of Laponite® products? The usual delivery forms for Laponite® are:

        25kg polyethylene lined cardboard cartons, shrink-wrapped 40 cartons to a pallet
        500kg and 1000kg woven polypropylene IBC (big bag), shrink-wrapped to a pallet
        Other weights can be supplied to order in IBC’s

Laponite® SL25 is supplied as a liquid dispersion…”Liquid Laponite”… 1000kg packed in an IBC.

30. What is the best pH range for Laponite®? Laponite® is a mildly alkaline material and is easiest to formulate at neutral pH and the basic side of the pH range. However, when handled correctly, it can be used to produce thixotropic rheology in, for example, skin creams at pH 5.5, surface coatings at pH 3, mineral acid based toilet cleaners at pH<1. Guideline starting formulations are available on www.laponite.com or request them directly from Rockwood by e-mail to help@laponite.com

31. What is the effect of temperature on Laponite® viscosity? Laponite® creates viscosity using a mechanism based upon electrostatic attraction of particles; the strength of these attractions is not affected by changes in temperature. As a result, the viscosity of the Laponite® structure does not change with temperature. However, in a formulated product, the viscosity of other components may change; usually viscosity is lowered as temperature increases. The viscosity of gums and polymers does change significantly as temperature changes. These materials thicken using forms of covalent bonding; such bonds reduce in strength as temperature increases. As a result, the viscosity of systems based upon gums and polymers will reduce as temperature increases.

32. What are the typical dimensions of a single crystal of Laponite®? When it is fully dispersed in water, Laponite® particles are in the form of disc-shaped nano-sized crystals. Type 1 products, e.g. Laponite® B, JS, XL21 are typically ~40nm diameter and ~1nm thick. Type 2 products, e.g. Laponite® RD, RDS, S482, SL25, XLG, XLS, are slightly smaller at ~25nm diameter and ~1nm thick.

33. When the word, “synergy” is used in relation to an interaction between Laponite® and another raw material, what does this word mean? Firstly, a wider definition of synergy…the potential ability for two or more materials when used together to develop an increase in one or more properties that is greater than might be predicted from observing the behaviour of the materials when used on their own.

Laponite® can demonstrate synergistic interactions with a wide range of co-thickeners. A common occurrence of this is viscosity synergy, which occurs in combinations of Laponite® with CMC (sodium carboxymethyl cellulose) to produce cost savings as a result of higher levels of viscosity build in formulations such as toothpaste. Another form is electrolyte tolerance synergy that occurs in combinations of Laponite® with xanthan gum. With this combination, it is possible to formulate products across the entire pH range, hydrochloric acid based toilet cleaners at pH 0.1, rust conversion coatings at pH 3, facial moisturisers at pH 5.5, emulsion paints at pH 8, household detergents at pH 9-10, depilatories at pH 12 and caustic oven cleaners at pH 14. Starting formulations for all of the above are available from Rockwood. Contact us on help@laponite.com with your requirements.

The group of gel forming grades, e.g. Laponite® XL21, RD and XLG are based on 100% synthetic layered silicate in composition. Sol grades are synthetic layered silicate modified with addition of dispersants. These are chemicals that have the effect of preventing formation of a gel structure in water; such a low viscosity (liquid) dispersion of a colloidal material is defined as a sol. Dispersions of sol grades can be activated by addition of the aqueous dispersion into a formulated product such as paint or toothpaste. More information is given on this on pages 20 & 21 of the Laponite® Technical Brochure. This is available at the following web link: http://www.laponite.com/pdfs/laponite.pdf

There are two types of Laponite® sol forming grades- “temporary” and “permanent”.

Temporary sol forming grades
The dispersant used in e.g. Laponite® RDS, XLS or JS is tetrasodium pyrophosphate (Na₄P₂O₇). Under manufacturing conditions, dispersions of these grades should be regarded as a temporary intermediate. The length of time for which a sol can be stored is known as its sol stability. The pyrophosphate ions which stabilise the Laponite® sol dispersion are themselves unstable in solution and slowly hydrolyse to produce simple phosphate:-

The charge density on the phosphate ion is much higher than on the pyrophosphate ion and does not produce a sol stabilising effect. As the edges of the crystals are once more free then particle-particle interactions can occur between positively charged edges and negatively charged faces. This reduces the mobility of the particles within the dispersion resulting in an increase in viscosity - when the process is complete a highly thixotropic gel is formed. The length of time for which a sol remains stable, at low viscosity, depends upon a number of factors:

Concentration• as concentration increases then Laponite® crystals are forced into closer contact with each other and viscosity increase will occur

Storage temperature• at elevated temperatures the rate of hydrolysis of pyrophosphate ion is accelerated and sol stability can be significantly reduced

Electrolyte level/water hardness• concentrated sols show maximum sol stability when deionised or soft water is used- in harder water, sol stability may be reduced

If water soluble compounds (such as surfactants, polyols, simple electrolytes) or latexes are added, then in some cases sol stability may be reduced. The addition of larger quantities of electrolyte such as would be caused by addition of the sol to a toothpaste or paint formulation will cause almost instantaneous viscosity increase.

Typical stability of temporary sol forming grades

Permanent sol forming grades

Laponite® grades, Laponite® S482 (supplied as a power) and Laponite® SL25 (supplied as a ready-to-use liquid dispersion at 25% solids content), are modified with patented dispersant additives. Under normal conditions, sol dispersions of up to 25% in water, of these grades will remain stable for over 1 year and can be regarded as “permanent” sols. The patented additives used in these grades form stable complexes at the edges of the Laponite® crystal, ensuring that aqueous dispersions remain at low viscosity for very long periods of time. On addition to a wide range of formulated products, they behave in the same way as temporary sol forming grades- a rapid increase in viscosity will occur.

For Type 2 products Laponite® RD, XLG, RDS, S482, XLS, CEC is typically 50 to 60 meq/100g.

37. Is Laponite® compatible with cationic surfactants? Laponite® products are anionic materials and will normally co-flocculate with cationic surfactants.

38. Can I use Laponite® to make conductive/ antistatic paints? Laponite® particles are intrinsically conductive and the product is widely used to make conductive/ antistatic treatments on surfaces such as paper and polymer films. In order for Laponite® to be an effective conductivising agent it must be present as the main component in the coating formulation. A typical conductivising formulation would contain 100 parts Laponite® JS to 10 – 20 parts emulsion resin binder at a total solids content of ~20%. When such a coating is applied onto a surface and dried, it ensures maximum and intimate contact of Laponite® particles with each other. As a result of this, the film is conductive. However, when Laponite® is included as an additive in a paint formulation, at e.g. <1%, then the other particulate components in the formulation, such as resins, fillers & extenders, will act as insulators and prevent the Laponite® particles coming into close contact with each other. As a result of this, combined insulation & dilution effect, Laponite® does not cause the paint to be conductive.

Formulating with Laponite®: A trouble shooting checklist and how to achieve optimum performance

This will help you to determine if the problem is related to the use of Laponite® in the formula. If these suggestions do not resolve the problem, please contact us for a more detailed discussion by e-mail at: help@laponite.com

41. Does Laponite® slow down rate of drying of a coating? Unlike many organic polymers, Laponite® does not have a mechanism to form hydrogen bonds with water and so does not slow down rate of drying to the same degree as many other thickeners. Laponite® does increase rate of drying when it used as a “set-up” agent to control rheology in ceramic glazes. The very high degree of shear thinning that is developed in systems that contain Laponite® ensure the water in the glaze formulation is absorbed rapidly in a ceramic piece as viscosity of the glaze is reduced by the shear stress created by capillary action that is generated at the surface of the ceramic piece.

42. What level/type of surfactants can be used with Laponite®? When handled in an appropriate manner, it is possible to thicken some systems that contain >30% active surfactants using Laponite®. However, in other systems, just a few per cent of surfactant may cause loss of viscosity. The very large ranges of different types of surfactants that are available make this a difficult question to answer other than in very general terms.

Some guidelines are given below:

        Synergistic increases in surfactant tolerance/ compatibility can often be developed by using Laponite® in combination with selected co-thickeners, such as some grades of xanthan gum or polyacrylate additives. This can allow preparation of relatively high surfactant content products, which can hold suspended actives, or, which are sprayable.

        Laponite® is anionic in nature and will co-flocculate with cationic surfactants. It is recommended that Laponite® products are not used for rheology control in formulations that contain cationic components.

        Laponite® will behave differently with mixtures of surfactants and other formulation additives than it will in simple combinations of Laponite®, water and surfactants X or Y. In many cases, it can show better compatibility with surfactants in complete formulations than it does in experiments to test compatibility with a single surfactant at a range of concentrations.

For additional help with using Laponite® in your own formulation, you are requested to contact us, by e-mail at: help@laponite.com

  44. What is the shelf life of Laponite®? The shelf life of Laponite® products is a minimum of two years from date of delivery, if stored as directed and in original packaging.

45. Where is Laponite® made? Laponite® products are made at Rockwood Additives Limited, Moorfield Road, Widnes, Cheshire WA8 3AA, United Kingdom. Rockwood Additives Limited is part of Rockwood Specialties Group Inc., a world class speciality chemical company, headquartered in Princeton, New Jersey USA. For more information, go to http://www.rockwoodadditives.com/ and http://www.rockwoodspecialties.com/index.htm.

46. Can you give guidelines on the best way to disperse Laponite?
How to disperse Laponite®: As with most speciality additives it is critical that Laponite® is introduced into formulations in the correct way. This will ensure that optimum performance and efficiency is achieved. All Laponite® products both gel forming and sol forming, must be added to water and allowed to disperse and hydrate fully before any other components are added. The presence of components such as surfactants, dispersing agents etc., already in solution will interfere with the dispersion of Laponite® and in some cases may halt it completely.

For gel forming grades and temporary sol forming grades
Add the free flowing Laponite® powder to deionised or tap water at room temperature (15-25°C) with rapid agitation. Mixer speed should be sufficiently high to produce a vortex which will cause all the powder to fully wet out without the formation of clumps. Suitable laboratory mixing equipment could be a mechanical stirrer fitted with a propeller blade revolving at 200rpm or a saw tooth (Cowles) blade revolving at 500rpm. Mixing should be continued for at least 20 minutes. If required, dispersion time may be reduced by increasing the temperature of the mixture up to 40-50°C after the Laponite® powder is fully wetted out or by use of a high shear mixer such as a Silverson. The viscosity of the Laponite® dispersion at this time depends upon the concentration of the premix and the Laponite® grade in use. The typical use level of Laponite® in a formulation may range from 0.05% up to 1%, or higher in some cases.

What’s a sol grade?- Click here for more information

For gel forming grades RD, XLG, D, DF

For temporary sol forming grades RDS, XLS, DS, S, JS

For permanent sol forming grade S482 To produce a sol at 20% solids or higher, use similar mixing equipment to that described above for gel and temporary sol forming grades…a mechanical stirrer fitted with a propeller blade revolving at 200rpm or a saw tooth (Cowles) blade revolving at 500rpm. Add the free flowing Laponite® powder quickly to deionised or tap water with rapid agitation at room temperature. Mixer speed should be sufficiently high to produce a vortex which will cause all the powder to fully wet out without the formation of clumps.

At very high solids content with Laponite® S482, there will be a rapid increase in viscosity of the mixture to produce a thick, paste-like texture within a few minutes. At this time turn off the mixer and allow the dispersion to age for up to one hour to allow the peptising effect of the patented additive to develop. The viscosity will fall rapidly during this time. Turn the mixing equipment back on and continue mixing for a further 30 minutes. Sols of Laponite® prepared in this way may be stored for very long periods of time before use.

Laponite® Technical Bulletin L246, Laponite® Safety Data Sheets and Product Data Sheets can be downloaded from our web site: www.laponite.com. From the home page, click on the Technical Information button and then select MSDS or PRODUCT BULLETINS from the menu that opens.

48. Where can I find information on Optigel® products? Rockwood purchased the Optigel® range of products from Süd-Chemie AG in January 2006. The so-called “Optigel S” series of synthetic layered silicates is now offered under the Laponite® brand name. Optigel® SH has been replaced by Laponite® RD; Optigel® S482 is re-named Laponite® S482; a liquid dispersion of Laponite® S482 at 25% solids content is offered under the grade name, Laponite® SL25. Page 4 of the Laponite® Technical Brochure gives more information on the range of Laponite® grades. This is available at the following web link: http://www.laponite.com/pdfs/laponite.pdf

Other Optigel® grades, based upon natural layered silicates, such as Optigel® CK, Optigel® CG, Optigel® WX, Optigel® WA, etc. continue to be offered by Rockwood. Visit www.optigel.com for more information on the range.

• Purified bentonites for water based systems: Bentolite®, Gelwhite®, Mineral Colloid®, Optibent®, Optigel®

• Organoclays & castor derivatives for solvent based systems: Claytone®, Garamite®, Tixogel®, Rheocin®

• Associative thickeners, non-ionic alkali swellable polymers: Optiflo®, Pure Thix®

• Nano-structuring agents for use in polymers: Cloisite®

For more information visit www.scprod.com and click on OUR PRODUCTS.

50. What is “Liquid Laponite®”? Laponite® SL25 is a ready-for-use low viscosity aqueous dispersion of Laponite® at 25% solids content. Product development work is underway to make Laponite® grades that remain stable as low viscosity dispersions in water for longer periods of time and at higher solids content. Such materials have often been described as “Liquid Laponite®”

51. Where can I order Laponite® samples/ get formulation or handling recommendations? The e-mail address help@laponite.com will connect you with our team of experienced technical specialists. Rockwood can provide useful formulation advice and handling recommendations, which can often assist our customers in shortening development times for their own new products. You can also use this e-mail address to request samples, or to make any commercial enquiries. Alternatively, contact us by telephone or fax at one of the addresses below: