Posts tagged ‘glass bubbles’

We are spoiled for choice when it comes to choosing a thermometer, from the trusty old mercury thermometer to modern-day digital sensors. Centuries ago, though, measuring the ambient temperature was performed by devices such as the Galileo thermometer.

A Galileo thermometer is a meteorological instrument consisting of a sealed glass tube filled with a clear liquid containing small glass bulbs of varying densities. Ambient temperature changes also alter the liquid’s density, causing different bulbs to rise or fall, which indicates the temperature.

Although this specific thermometer as we know it today wasn’t designed by Galileo himself, all the principles that the thermometer is based upon were discovered and implemented by Galileo Galilei and his thermoscope.

What Is A Galileo Thermometer?
A Galileo thermometer is a meteorological instrument consisting of a sealed glass tube filled with a clear liquid containing small glass bulbs of varying densities. Ambient temperature changes also alter the liquid’s density, causing different bulbs to rise or fall, which indicates the temperature.

Each bubble is partially filled with a different colored liquid. Small metal tags of different weights are also hanged below each bulb to adjust their “density,” while each tag also contains a number.

Any changes in air temperature change the density of the liquid as well. This causes the bubbles inside the liquid to rise and fall in response to changes in the fluid’s density.

By observing the different heights at which the glass bubbles are floating, the temperature can be determined. This is done by identifying the number of the tag below the bubble floating at the “right height.”

If this sounds confusing to you, you are not alone. If I only described to you what a Galileo thermometer looks like and how it responds to temperature changes, it would be difficult to understand what is really happening and why.

One needs to understand the principles and forces at work that make all the parts in this thermometer behave the way they do and how they all work together to help determine the atmospheric temperature.

ARTICLE SOURCE: ownyourweather

RTP Company announces the availability of specialty compounds containing hollow glass microspheres which reduce part weight, enhance properties and lower part costs in demanding applications.

High loadings of these microspheres, which are manufactured by 3M and known as ScotchliteTM Glass Bubbles, can be added to thermoplastics to reduce overall part weight, and thus per part material costs. Additionally, they can modify polymer characteristics, achieving lower viscosity, improved flow, and reduced shrinkage and warpage.

For example, some compounds containing ScotchliteTM Glass Bubbles can have their specific gravity reduced by as much as 30 percent. The use of glass bubbles also provides more uniform control and reproducibility than other methods typically used for weight reduction, such as foaming agents.

ScotchliteTM Glass Bubbles reduce thermal conductivity and lower dielectric constants of most thermoplastics. Non-combustible and non-porous, the glass bubbles do not absorb moisture. Compounds containing ScotchliteTM Glass Bubbles are available in most engineering resins and easily adapt to common processing methods, including injection molding and extrusion. Applications that can benefit from this weight saving technology exist in the aerospace, automotive, marine, electronic, and medical industries.

FROM:RTP Company

Technology created by researchers at the Okinawa Institute of Science and Technology Graduate University (OIST) is literally shedding light on some of the smallest particles to detect their presence – and it’s made from tiny glass bubbles.

The technology has its roots in a peculiar physical phenomenon known as the “whispering gallery,” described by physicist Lord Rayleigh (John William Strutt) in 1878 and named after an acoustic effect inside the dome of St Paul’s Cathedral in London. Whispers made at one side of the circular gallery could be heard clearly at the opposite side. It happens because sound waves travel along the walls of the dome to the other side, and this effect can be replicated by light in a tiny glass sphere just a hair’s breadth wide called a Whispering Gallery Resonator (WGR).



A magnified photograph of a glass Whispering Gallery Resonator. The bubble is extremely small, less than the width of a human hair.




When light is shined into the sphere, it bounces around and around the inner surface, creating an optical carousel. Photons bouncing along the interior of the tiny sphere can end up travelling for long distances, sometimes as far as 100 meters. But each time a photon bounces off the sphere’s surface, a small amount of light escapes. This leaking light creates a sort of aura around the sphere, known as an evanescent light field. When nanoparticles come within range of this field, they distort its wavelength, effectively changing its color. Monitoring these color changes allows scientists to use the WGRs as a sensor; previous research groups have used them to detect individual virus particles in solution, for example. But at OIST’s Light-Matter Interactions Unit, scientists saw they could improve on previous work and create even more sensitive designs. The study is published in Optica.

Today, Dr. Jonathan Ward is using WGRs to detect minute particles more efficiently than ever before. The WGRs they have made are hollow glass bubbles rather than balls, explains Dr. Ward. “We heated a small glass tube with a laser and had air blown down it – it’s a lot like traditional glass blowing”. Blowing the air down the heated glass tube creates a spherical chamber that can support the sensitive light field. The most noticeable difference between a blown glass ornament and these precision instruments is the scale: the glass bubbles can be as small as 100 microns– a fraction of a millimeter in width. Their size makes them fragile to handle, but also malleable.

Working from theoretical models, Dr. Ward showed that they could increase the size of the light field by using a thin spherical shell (a bubble, in other words) instead of a solid sphere. A bigger field would increase the range in which particles can be detected, increasing the efficacy of the sensor. “We knew we had the techniques and the materials to fabricate the resonator”, said Dr. Ward. “Next we had to demonstrate that it could outperform the current types used for particle detection”.


A diagram showing the new WGR experiments. Test particles (shown here in green) are passed through a light field, which distorts the light wavelength, which can be used to detect the particles.


To prove their concept, the team came up with a relatively simple test. The new bubble design was filled with a liquid solution containing tiny particles of polystyrene, and light was shined along a glass filament to generate a light field in its liquid interior. As particles passed within range of the light field, they produced noticeable shifts in the wavelength that were much more pronounced than those seen with a standard spherical WGR.

With a more effective tool now at their disposal, the next challenge for the team is to find applications for it. Learning what changes different materials make to the light field would allow Dr Ward to identify and target them, and even control their activity.

Despite their fragility, these new versions of WGRs are easy to manufacture and can be safely transported in custom made cases. That means these sensors could be used in a wide verity of fields, such as testing for toxic molecules in water to detect pollution, or detecting blood borne viruses in extremely rural areas where healthcare may be limited.

For Dr. Ward however, there’s always room from improvement: “We’re always pushing to get even more sensitivity and find the smallest particle this sensor can detect. We want to push our detection to the physical limits.”
By Andrew Scott

As the search continues for lower material costs, without sacrificing performance or processability, glass bubbles are getting more attention. Reducing density with additives is not new, but bubbles are showing advantages.

As the search continues for lower material costs, without sacrificing performance or processability, glass bubbles are getting more attention. Reducing density with additives is not new, but bubbles are showing advantages.

Resin compounder Noble Polymers (Grand Rapids, MI), a subsidiary of manufacturer Cascade Engineering, has developed a low-density resin formulation that reduces the weight of parts molded of TPO (thermoplastic polyolefin) by up to 20%. It’s a masterbatch bulk resin additive that incorporates hollow glass bubbles to displace resin and reduce part density in molded, thermoformed, and extruded products.

“Mandated standards for Corporate Average Fuel Economy (CAFE), along with the drive to reduce industrial emissions and achieve more sustainable production methods, have led to a growing demand for enhanced TPO production methods,” says Tim Patterson, Noble Polymers business unit manager. “Glass bubble additives in our masterbatch material displace hydrocarbon-based resin content and lighten parts to help cut transport fuel consumption.

“Use of density-reducing agents for filled TPO raw material is not a new concept,” Patterson continues. “While various filler materials have been used to reduce TPO part density, glass bubbles have significant process and resin displacement advantages over alternate fillers. We’ve found that the addition of glass bubbles yields secondary benefits to TPO components as well, including improved part stiffness, greater dimensional stability, and reduced shrinkage.”

Patterson says traditional resin-displacement mineral fillers such as cenospheres, asbestos particulate, chopped glass fiber, and calcium carbonate (CaCO3) have considerably less volume per unit weight than glass bubbles. For example, 1 kg of typical glass bubble material has a volume of 1666.7 cm3, while the equivalent weight of CaCO3 displaces only 370.4 cm3. Thus its resin displacement potential per unit of weight is only a fraction of that of glass bubbles.

Glass bubble selection
Wang says the class of bubbles selected for a masterbatch depends on the end use of the TPO component. For example, the pressures involved in TPO molding require glass bubbles with elevated crush strength. Glass bubble strength is generally proportional to density, and thus lower-strength bubbles are less dense, and offer greater potential for TPO weight reduction than thicker-walled, higher-strength bubbles.

According to Wang, bubble size impacts TPO surface finish as well as stress transmission through the composite, with smaller bubbles contributing to more favorable impact and tensile properties. “In general, higher-strength bubbles are required for injected molded interior and exterior automotive components, and other industrial components,” says Wang.

Noble’s development work shows that mold shrinkage in a TPO part is inversely proportional to the volume percentage of glass bubbles in the mix. The modulus (stiffness) of a part also increases in proportion to the ratio of glass bubbles to resin. The positive attributes of increased stiffness and heat distortion temperature (HDT) as well as decreasing coefficient of linear thermal expansion (CLTE), shrink, warp, and sink marks continue to improve as the percentage of glass bubbles in the resin mix rises. Tensile strength, elongation, and impact strength tend to decrease as well. Complementary additives in the masterbatch can modify these values to some degree.

“In general, plastics are flexible and experience ductile failure under stress, while glass adds stiffness but is more prone to brittle breakage,” said Wang. “It is possible to improve TPO impact strength by adding an impact modifier to the masterbatch that reduces potential for brittle failure while maintaining the stiffness advantage.”

According to Wang, the concentration of glass bubbles in a masterbatch additive mix varies, but can be as much as 50% by weight, depending on customer requirements. Finished parts made using this masterbatch glass bubble concentration will be 20% or more lighter than resin-only parts.

“Process tests show that a Noble masterbatch formulation with glass bubbles can cut TPO injection molding production time as much as 20%,” says Wang. “This benefit is apparently related to changes in thermal properties that result from displacing resin with hollow glass (reduced mass), and the resulting time savings are concentrated primarily during the cooling period.”

In addition to automotive, exploring markets such as building materials, composite materials, sporting goods, and construction applications, where benefits seen include weight reduction, processing improvements, and product design enhancements, according to William Donahue, business manager, Resin System Additives.

And the cost compared with straight TPO? “There is a premium that can be offset by manufacturing improvements, weight reduction, and/or product enhancements,” says Donahue. “The potential cost savings depends upon the density and the cost of the polymer.”

Noble Polymers works with individual customers to determine precise TPO part specifications, and multiple interests are weighted in a staged/gate process to achieve optimum density reduction while meeting necessary physical specifications. The resulting formulas are confidential and proprietary to customers. Patterson estimates that nearly half of the company’s TPO masterbatch customer applications call for some degree of formula customization, while the balance can be met using the company’s standard masterbatch material.


We will take a closer look at how the unique morphology of Glass Bubbles translates to benefits in modern composite systems. We will also explore the latest in Glass Bubbles technology for composites systems.

What are Glass Bubbles?
Glass Bubbles are tiny, hollow glass microspheres. They appear as a white free-flowing powder and are made from a water-resistant and chemically stabile soda-lime-borosilicate glass. Originally developed by 3M in the 1960s, they can nowadays be found almost everywhere: from the deep seas to the stratosphere, from specialist industrial applications to consumer goods. Cars, airplanes, bowling balls, fishing line, snowboards, deck chairs, and so on, all make use of the unique properties of Glass Bubbles.

The composites sector recognised early on that Glass Bubbles have an exceptional ability to reduce the weight of composite parts. Compared to conventional fillers such as talc or calcium carbonate, the density of Glass Bubbles can be 20 times lower (depending on the grade). Glass Bubbles have since become ubiquitous in resin systems including polyesters, polyurethanes, and epoxies.

Glass Bubbles are hollow glass microspheres that behave like free-flowing powders. The automotive industry has embraced these materials for their unique ability to lightweight parts as well as add other benefits.
The automotive industry in particular embraced Glass Bubble technology as lighter parts translate to improved fuel economy. In cars and trucks, Glass Bubbles can be found in composite parts such as exterior body panels, roofs, headlight reflectors, wind deflectors, fenders, floorboards, access doors, and internal panels such as engine housings and spare tire wells.

While Glass Bubbles are best known for their ability to reduce the weight of parts, this is far from their only feature. Modern applications in composites rely on the ability of Glass Bubbles to improve processing and to enhance the properties of the final composite parts. Processing improvements generally refer to the ability to produce parts at increased production speed and with greater ease. Property enhancements refer to complementary functionalities brought on by the Glass Bubbles. These can be extremely diverse, ranging from mechanical properties (stiffening) to fire-retardant properties, acoustics & dampening, and thermal insulative properties.

Glass Bubbles are lightweight
The density of Glass Bubbles ranges from 0.15 g/cc to 0.60 g/cc. In contrast to other mineral fillers such as chopped glass fibre, calcium carbonate and talc, the volume per unit of weight is therefore much greater. Replacing inorganic fillers with Glass Bubbles therefore results in composite parts with reduced density. For example, 1 kg of typical Glass Bubble material (K20) has a volume of 5000 cm3, while the equivalent weight of CaCO3 displaces only 370.4 cm3. Due to the extremely low densities of Glass Bubbles, formulation, therefore, needs to be on a volume basis rather than a weight basis. If one were simply to substitute an equal weight of Glass Bubbles for the calcium carbonate in a formulation, the volume ratio of all other ingredients would be reduced substantially. Formulating by volume instead of weight allows the proper balance of resin, filler, and reinforcement, so components can be made lighter while still maintaining a good balance of physical properties.

An older but useful example of the use of Glass Bubbles to precisely control the weight of the final part can be found in the manufacturing of bowling balls. Here, the inner cores of bowling balls are prepared using a cast polyester resin. The more Glass Bubbles used in the resin, the lower the density of the bowling ball. Therefore, the final weight of the bowling ball can be adjusted precisely and easily by adjusting the volume concentration of Glass Bubbles in the resin. Importantly, the addition of Glass Bubbles does not affect the stability of the resin, and the resin mixture remains free-flowing. As this simple example highlights, Glass Bubbles have more to offer advanced composite materials besides the obvious density reduction. In the next section, we will explore the secondary benefits and how they relate to the unique physical characteristics of Glass Bubbles.

When incorporating Glass Bubbles into a composite, one is essentially replacing a fraction of resin and/or solid fillers with uniform and microscopic pockets of air. The replacement of resin by air results in some unique side effects.

For example, the reduction of mass in turn reduces the heat capacity of the resin, which in turn results in shorter cooling times allowing parts to be produced faster. Moreover, the composite’s coefficient of linear thermal expansion (CLTE) decreases. The low CLTE means that larger composite parts can be manufactured, and these are less prone to deformation during cooling, also known as warpage.

The low CLTE can also provide benefits in the finished parts. For example, solid parts engineered using Glass Bubbles (e.g. roofing trims) will be less prone to cracking when exposed to hot/cold cycles.

In a similar vein, the thermal conductivity is lowered by the presence of Glass Bubbles. The resulting thermally insulative parts find extensive use in energy-saving applications (e.g. bathtubs which keep water warm for longer) and also add value to various consumer goods (e.g. steering wheels or shower trays which are warm to the touch).

Replacing resin and solid fillers with hollow Glass Bubbles also lowers the calorific content of the composite part. A useful side effect of this property is that fire retardant performance is improved by the introduction of hollow Glass Bubbles – simply put there is less material to burn – resulting in better fire ratings. Recently researchers also discovered secondary mechanisms by which the hollow nature of Glass Bubbles leads to a fire hazard reduction, for example in rigid foams.
The hollow nature of the Glass Bubbles further impacts the composite’s interaction with light and sound waves. This property finds its use in specialised applications such as acoustic damping.

Glass Bubbles, as the name implies, are perfectly spherical. Glass Bubbles therefore have the lowest possible surface to volume ratio of any filler. As a result, Glass Bubbles require less resin to be wetted out compared to non-spherical fillers. In many cases this means that the resin content can be lowered, resulting in cost savings and reduction of VOC emissions.

Another side effect of the spherical nature of Glass Bubbles is that the effect on the viscosity of the resin is minimised. This property is often described as a ‘ball-bearing’ effect. A better flowing resin not only allows parts to be produced more quickly, but it also results in a more isotropic filling of the mould. This in turn leads to composite parts in which stresses are more uniformly distributed. In contrast, angular fillers such as talc or glass fibres tend to interlock at higher loadings resulting in stress concentrations and fracture points in the cured part.

A great example of a technology that has successfully exploited the low viscosity impact of Glass Bubbles is Reaction Injection Moulding (RIM). RIM is a manufacturing process in which liquid polyurethane or polyurea precursors are combined, injected into a mould, and subsequently polymerised to produce the part. Since the resin is introduced into the mould as a liquid, flowability of the resin is key to ensure the precise reproduction of components with thin walls and complex geometries. Glass Bubbles work in this application to maintain flowability and to reduce the density of the parts, typically alongside heavier reinforcing fillers such as acicular Wollastonites.

Glass Bubbles are closed spheres consisting of a chemically stable soda-lime-borosilicate ‘shell’, so they are intrinsically stable toward heat damage and chemical degradation. Glass Bubbles can therefore be added into most resin systems including polyester, epoxy, and polyurethane. Their size, shape, and chemistry will not be affected by processing conditions such as temperature, humidity, nor will their properties change over time, such as during storage. The dimensional and chemical stability of Glass Bubbles is a unique advantage over other lightweight fillers such as plastic microspheres.

The stability of Glass Bubbles is particularly useful in applications in which there is some delay between mixing and curing of the resin formulation, which includes epoxy or polyester marine putties, adhesives, sealants, and polyurethane structural foams.

Glass Bubbles can withstand high external pressures due to their spherical shape and chemical make-up. The strength of Glass Bubbles quantified as the isostatic crush strength, which is dependent on the grade and varies between 100 to 30 000 PSI. Since the crush strength of a specific grade depends greatly on the wall thickness, the crush strength and density of the grade are inversely related. As a result, the selection of a grade of Glass Bubble for a specific application is usually determined by the crush strength required to survive the processing during manufacturing of the part.
Sheet moulding compound (SMC), the most prominent mass manufacturing technique to produce large composites structures, is a great example of a process in which the high strength of Glass Bubbles is of benefit. SMC is produced in sheets that consist of a thermosetting resin combined with glass fibres and other fillers. The SMC is moulded by part manufacturers under high pressure and subsequently cured. As described in the introduction, the automotive industry relies on SMC to fabricate both external surfaces (body panels, roofs), as well as internal panels (engine housing, spare tire wells, floorboards). SMC is also widely used in structural applications ranging from trench covers to lightweight roofing panels.

Author: Koen Nickmans , Ph.D.

Glass bubbles are finely dissipated, free-streaming fine particles created by dissolving a unique glass equation which comprises of an inert blowing specialist which makes the liquefied glass particles swell into an empty air pocket. The subsequent glass bubbles are water-safe, and viable and synthetically stable with different materials that are utilized for aberrant food contact applications. In the coming years, material innovation has developed to make bubbles with high solidarity to thickness proportion, subsequently empowering its utilization in requesting polymer handling activities.

On the flipside, inflexible and underlying properties of glass bubble froth give an extra protection worth to dividers and lodgings. Moreover, glass bubbles convey weight decrease for thermosets, thermoplastics, and elastomeric polymer substrates. This aides lessening transporting cost and furthermore facilitates establishment issues. The expansion of glass bubbles to polymers changes its actual property. Adding glass to bubble polymers makes the composites stiffer when contrasted with its unique unfilled base gum. This is valuable in the assembling of solid yet light lodgings and parts.

Nevertheless, the quick extension of the auto business, particularly in the U.S., is expected to help the market during the gauge time frame. Besides, severe discharge control guidelines in the U.S. what’s more, different nations in the Europe is expected to fuel the interest for glass bubbles at a huge speed in the years to come.

hollow glass microsphere

Additives, particularly inorganic solid minute particles, have significantly contributed to the development of the polymer industry. Depending on their geometry and chemistry, additives provide polymers with better physical, thermal, electrical, mechanical, and dimensional properties. Glass bubbles are finely scattered, free-flowing fine particles with an average diameter of 15-65µm, and consists of thin-walled, sphere-shaped glass particles (0.5-1.5µm). They were first developed in the 1960s, as an extension after the production of solid glass beads. Glass bubbles are produced by melting a special glass formula which consists of a latent blowing agent which causes the melted glass particles to swell into a hollow bubble. The resulting glass bubbles are water-resistant, and compatible and chemically stable with various materials that are used for indirect food contact applications. In the recent years, material technology has evolved to manufacture bubbles with high strength to density ratio, thus enabling its usage in demanding polymer processing operations.

Glass bubbles provide design solutions for innovative users and new and elite materials. Moreover, they provide polymers with low-density that can be related directly to insulation properties and thermal conductivity. The three polymer types, viz., high impact polystyrene (HIPS), polyurethane (PU), and polypropylene are commonly used in applications such as housings, and walls or as foam for insulation, especially in the case of thermoset polyurethane (PU). PU foam for insulation are made with chemical blowing agents and are usually attained at very low density (0.20 – 0.40 g/cc). The PU composite density with glass bubbles is in the range of 0.76 – 0.95 g/cc; therefore, they are not compatible with urethane for attaining maximum insulation properties. However, rigid and structural properties of glass bubble foam gives an additional insulation value to walls and housings. Furthermore, glass bubbles deliver weight reduction for thermosets, thermoplastics, and elastomeric polymer substrates. This helps reducing shipping cost and also eases installation issues. The addition of glass bubbles to polymers changes its physical property. Adding glass to bubble polymers makes the composites stiffer as compared to its original unfilled base resin. This is useful in the manufacturing of strong yet light housings and parts.

The glass bubbles market can be segmented based on application and region. In terms of application, the market can be segmented into automotive and commercial vehicles, aircrafts, and recreational and marine vehicles. In terms of geography, the glass bubbles market can be segmented into North America, Europe, Asia Pacific, Middle East & Africa, and Latin America. North America dominated the global glass bubbles market in 2016, followed by Europe, and this trend is anticipated to continue during the forecast period. Moreover, rapid expansion of the automobile industry, especially in the U.S., is anticipated to boost the market during the forecast period. Furthermore, stringent emission control regulations in the U.S. and various other countries in the Europe is anticipated to fuel the demand for glass bubbles at a significant pace during the forecast period. The market in Asia Pacific is expected to expand at a considerable pace during the forecast period owing to the implementation of stringent government norms concerning volatile organic content (VOC) emissions from automobiles in countries such as China and India, while the market in Middle East & Africa and Latin America is likely to expand at a moderate pace during the forecast period.

Key players operating in the global glass bubbles market include 3M, Sinosteel Maanshan New Material Technology, and others.

FROM:Transparency Market Research

Syntactic foams are complex compounds produced by the incorporation of hollow spherical particles into a polymeric or ceramic matrix. The American Society for Testing and Materials (ASTM) states that synthetic foams have a resin matrix.

The properties of synthetic foam can be largely determined by changing some parameters during their production such as the material of the matrix and fillers, the size of the microspheres, the thickness of their wall and their number – meaning mostly the ratio of their volume with the total volume of foam. The easiness of production is another important advantage of synthetic foams.

Epoxy synthetic foams are preferred as a matrix material due to their good mechanical properties such as durability and stiffness, small creep and moisture resistance.
Structural polyamide foams have very good mechanical and electrical properties and their use is great in electronic devices. They are usually combined with silicon spheres.
Structural polyurethane foams have good compressive strength and high water resistance. They can be soaked in a humid environment for over 10 years and at a water temperature of up to 40oC without significantly degrading their properties.
Polyester synthetic foams in combination with hollow glass microspheres have found great application in the construction of marine vessels and underwater structures due to their buoyancy, non-adsorption of moisture and their low cost.
Polypropylene is used with hollow glass spheres to have low density, good mechanical and thermal insulation properties.

The main properties of synthetic foams that gave impetus to their production and growth include among others their reduced weight, increased rigidity, buoyancy and reduced cost. If we take into account their resistance to compression and hydrostatic loads, their relatively good response to impact and fatigue and their resistance to abrasion and chemicals, we understand why they have been widely applied in various types of constructions.


Single From a cost perspective, if the hollow glass bubbles per unit mass of the same price, you should use the lowest possible density of hollow glass microspheres, so low unit cost.If just from a performance standpoint, because the larger the lower the density of the hollow glass microspheres diameter, large diameter also reduces the conductivity between the zinc coating, which reduces the resistance to salt spray paint, and therefore should be chosen particle size as small as hollow glass microspheres.There are on the one hand I must mention that, due to the formulation of other fillers such as zinc and iron phosphate high density, when the coating solution is stirred crashed hollow glass microspheres, and in the spray when a low intensity hollow glass microspheres are easily broken failure. Therefore, the density of the microspheres can not be selected too large, the particle size can not be too large, and the strength is sufficient.

Proposal to add the following methods:
In order to take full advantage of the characteristics of the hollow microspheres, recommended adding a last resort, that is added to the beads into the final as low speed mixing equipment dispersed using low shear force, because the spherical beads mobility well, between the friction is not large, so it is easy to disperse. You can complete a short wet, slightly extended mixing time to achieve uniform dispersion.
Beads chemically inert, non-toxic. However, because of a very light, so they need special attention added.Recommended stepwise addition method, which is the amount for each remaining 1/2 beads gradually added, this can be good to avoid beads float into the air and dispersed more complete.

Sinosteel Maanshan New Material Technology Co., Ltd.

K25 glass bubbles have a density of 0.25 g/cc and an isostatic crush strength of 750 psi.

Lower viscosity, improved flow
Increased filler loading, reduced cost
VOC reduction
Chemical stability and inertness
Reduced dielectric constant
Thermal conductivity reduction
Temperature resistance

Paints and coatings
Insulation and buoyancy