Boron in Other Applications

A MULTITUDE OF USES

Boron truly is an integral part of modern life. Aside from its numerous primary applications—as a component in borosilicate glass, textile fiberglass, agriculture, wood protection, industrial processes, detergents, metallurgy, insulation, energy production, adhesives, and ceramics—boron and borates are used to:

Gypsum board

Gypsum board is widely used for internal walls and ceilings. As part of its manufacture, Optibor® boric acid can:

  • Increase strength
  • Reduce weight by about 10%
  • Provide better adhesion of the paper backing
  • Reduce curing time
  • Prevent wrinkle formation on the surface
  • Create a hard gypsum edge that withstands nailing and handling
  • Enhance fire retardancy

Adding Optibor to the gypsum slurry promotes the formulation of large bulky crystals (as opposed to long needle-like ones). These crystals impart a more rigid character, strengthening the board and providing a harder outer edge. They also result in faster drying times.

When also used in the starch adhesive that is used to reinforce the bond between wallboard’s paper backing and gypsum core, Optibor provides increased viscosity, quicker tack, and better fluid properties—all essential for the dependable adhesion of the paper to the core. Optibor also reacts with sodium (found in many gypsum deposits), preventing the sodium from creating wrinkles in the paper backing as the wallboard dries.

Optibor’s fire-retardant properties help prevent the paper backing from burning while in the oven and helps to protect the final product by inhibiting combustion and suppressing afterglow and smolder. And Optibor helps minimize issues that can result from the injection of foam into the slurry (as part of density and weight reduction processes).

Borates in gypsum board

PRODUCTS

Industrial-strength powdered hand soaps

Powdered hand soaps enjoy a considerable share of the industrial hand-cleaning market. Typically, powdered cleaning preparations consist of a high-grade soap and an abrasive material (a scrubber). Refined versions also contain builders to improve detergency, fatty materials to impart softness, and perfumes and dyes for aesthetics. Of course, these products’ prime purpose is to remove soils—primarily medium-to-heavy soils, such as are encountered in industrial operations.

For this reason, the scrubber is perhaps the most important component in the formulation. An effective scrubber should:

  • Quickly and efficiently remove industrial soil
  • Contribute to detergency
  • Be pleasant (or at the very least, not unpleasant) to use
  • Resist degradation

Scrubbers should not abrade skin, be a skin sensitizer, or clog plumbing.

Available scrubbers can be broadly classified into two categories: soluble and insoluble. Soluble scrubbers are generally a granular material that scrubs and lessens the soil before dissolving. The most widely used and efficient soluble scrubber is 20 Mule Team® Borax borax decahydrate. Its advantages are many:

  • Is available in a range of particle sizes to enable soap formulators to tailor the abrasive quality to meet market demands
  • Improves detergency by offering pH control
  • Enhances the removal of pigment and oily soils
  • Aids water softening by binding with calcium ions to form soluble complexes
  • Provides quick cleaning and free rinsing Is gentle to the skin yet highly effective in removing imbedded dirt
  • Does not sensitize Is not susceptible to degradation, allowing longer shelf life
  • Does not clog drains Is not susceptible to insects or micro-organisms
For more information, download Borates in Powdered Hand Soap.

Borates in hand soap

 

FACT

Borax Decahydrate

The most widely used and efficient soluble scrubber is borax decahydrate.

Personal care

Borates and their derivatives have been used, recommended for use, and patented for a variety of personal care products. Many of these products have a regulatory requirement to use our pharmacopeia grades: borax decahydrate NF or borax decahydrate EP, Optibor NF or Optibor EP. In addition to their excellent cleaning functions, borates are used in in these products for the following reasons:

  • pH buffering
  • Viscosity or rheology control (crosslinking with starch or polymers)
  • Emulsification with oils or waxes
  • Enzyme stabilization or inhibition
  • Foam stabilization
  • Moisture retention
  • Active oxygen carrier (as in perborates)

Skin care: Borates—primarily borax decahydrate and Optibor are used in conjunction with beeswax, almond oil, spermaceti, oil, petrolatum, sodium carbonate, stearic acid, glycerin, and perfume in the production of numerous personal care products:

  • Cold creams (used to remove makeup)
  • Baby creams
  • Petroleum jelly
  • Moisturizing lotions and creams
  • Anti-aging creams
  • Shaving creams
  • Bath salts
  • Cleansers (as a buffer)
  • Sunscreen
  • Liquid hand soap and bar soaps

Oral hygiene: Borates are used in some specialty toothpaste and mouthwash products. Toothpaste can use a mixture of calcium peroxide and sodium perborate as oxidizing agents to remove stains and plaque from both teeth and composite filling material. But the largest use of borates for oral hygiene is in denture-cleaning products, where they are valued for their cleaning, bleaching, disinfecting, and effervescing properties.

Hair care products: Borates are used in a variety of powdered and liquid shampoos and conditioners. In shampoos, 20 Mule Team Borax borax is used in conjunction with soda ash, Fuller’s earth, talc, perfume, castor oil, petrolatum, wax, and preservative. In conditioners, borax is used in conjunction with methylparaben, mineral oil, lantrol, lanogel, lanolin, petrolatum, and beeswax. Shampoos consisting of borax decahydrate, colorant, and perfume can provide conditioning and make hair manageable and attractive. Borates are also a vital ingredient in rinse-free shampoos, which have a high water content and an absorbent gel that entraps the dirt without leaving residue. Optibor has been used in hair dye, neutralizing rinses, and both chemical relaxers and permanent wave solutions.

Eye care products: Eyedrops (artificial tears) are used to moisturize irritated eyes, remove redness, or relieve the itching associated with allergies and colds. Both borax decahydrate NF and Optibor NF are frequently added in small quantities to these products, to help control pH and retain moisture. Sterile saline solutions for contact lenses are often buffered with small quantities of these 20 Mule Team Borax products, which are also included in lens rewetting drops that can make the lenses more comfortable to wear. For more information, download Borates in Personal Care Products.

Borates in personal care

 

Borax Decahydrate

The inclusion of peroxy compounds (e.g., sodium perborate) in the preparation of selenium sulfide-containing shampoo compositions provides anti-dandruff efficacy and color stability without requiring the use of a buffer system.

Wire drawing

To make wire, metal rods are drawn through dies of successively decreasing diameter. Lubricant is necessary to reduce the friction between the rod and the dies. Because the lubricant—a drawing soap or grease—does not adhere well to the rod, a lubricant carrier is necessary. The carrier must form a tenacious coating on the rod, to which the lubricant will readily adhere. Either Neobor® or borax decahydrate can be used as an effective lubricant carrier—and can also be used to neutralize residual acid (from the removal of oxides prior to adding the lubricant) and prevent corrosion during storage. Throughout the cleaning, coating, baking, and drawing processes, these borates provide:

  • Ease of solubility in hot water
  • Dust-free operation
  • Long borate bath life and decreased need for agitation
  • Compatibility with electric resistance heat units
  • Easy air drying
  • Compatibility with calcium and sodium soaps
  • Longer life than can be achieved with lime
  • Superior performance on high carbon steel (e.g., spring steel)
  • Enhanced phosphate coatings
  • Ease of removal from the rod or wire. if desired
For more information about the use of borates in wire drawing, download Borates in Wire Drawing and see Boron in Industrial Fluids and Lubricants, Boron in Insulation and Polymers, and Borates in Metals and Gold.

Automotive

Borates are used in the manufacture or composition of numerous automotive parts, from frames to windshields to oil and lubricants.

For more information about the use of borates in individual automotive components and processes, see Boron in Glass and Textile Fiberglass, Borax in Industrial Fluids and Lubricants, and Borates in Metals and Gold.

Borates in automotive industry

Fire retardancy for cellulose materials

Cellulose—the basis of wood, cotton, and most other plant-derived raw materials—is in widespread industrial use. But in many forms, cellulose is inherently flammable. The use of borates in cellulose materials imparts flame retardancy, enabling them to meet stringent safety standards and helping to protect consumers.

The three major uses of borate flame retardants for cellulosic materials are in cellulose insulation, wood products and composites, and cotton batting (used as a filler in mattresses and futons). Because most borates are water-soluble, they are not suitable for clothing or materials that are laundered regularly. The decision to use borates depends on several factors:

  • The type of product
  • The application methods
  • The compatibility with other additives
  • Compliance with fire test standards

Combustion of cellulosic materials can occur both in a primary mode, where visible flames are present, and in a secondary mode, where flames are absent. The latter case is referred to as glowing or smoldering, depending on whether light is emitted.

In cellulose insulation, wood composites, mattresses, fabrics, and paper, borates are used primarily to prevent flaming combustion and to suppress glowing and smoldering. Optibor has long been recognized as an effective flame retardant additive due to its ability to prevent smoldering and is often used to help protect cotton-batting infill material in mattresses and futons. The combination of Optibor and Neobor yields reliable fire and corrosion test performance. Flame-retardant lumber, plywood shingles and shakes, and wood composite board can be made by vacuum or pressure impregnation with Optibor or Polybor® sodium borate solutions. These solutions can also be applied by direct spraying or dipping to drapes or curtains, rugs, ironing-board covers, firefighter uniforms, fabric heat deflectors for stoves or fireplaces, and fire-smothering blankets. Solutions of Optibor, Polybor, or 20 Mule Team Borax ammonium pentaborate can be applied to paper, such as high-gloss file-storage boxes, although the products have a stiffening effect that must be offset.

For more information about the use of borates in fire retardancy, download Borates for Fire Retardancy in Cellulosic Materials and see Borax in Wood Protection and Biocides and Boron in Insulation and Polymers.

Borates in cellulose materials

 

FACT

Borax Decahydrate

Laboratory work has confirmed that boric acid is the most effective chemical additive in cotton mattresses.

Water treatment processes

Semi-permeable membranes used in wastewater treatment are cleaned with a solution of sodium perborate tetrahydrate and EDTA, which gives better results than acid washing. In heat-exchange devices, corrosion of metals or alloys can be combatted through the use of borates, which in the presence of oxygen promote the formation of a passivating layer (ferric oxide film) that prevents further oxidation.

For more information about the use of borates in water-treatment chemicals, see Borax in Industrial Fluids and Lubricants.

Borates in water treatment

Autocausticizing

Patented Partial Borate Autocausticizing (PBAC) technology is implemented in pulp mills to supplement conventional lime causticizing, with little or no capital investment. These mills typically use PBAC to:

  • Reduce fresh lime consumption and lime mud disposal
  • Reduce fresh lime or caustic purchases
  • Increase white liquor/pulp production
  • Off-load lime kiln (energy/maintenance savings)
  • De-bottleneck causticizing circuits

PBAC uses Neobor to react with sodium carbonate in the kraft pulping furnace to form intermediate borates. Once the reacted salts are dissolved in the green-liquor dissolving tank, sodium hydroxide is formed, and the intermediate borates are regenerated. 

Borates in autocausticizing

 

PRODUCTS

Refractories

Ammonium pentaborate can be used in gunning and patching compounds, to extend the life of basic refractories in steel furnaces. 20 Mule Team Borax boric oxide is used in the manufacture of chemically bonded firebricks—as a binder for magnesia-based bricks and as a stabilizer for dolomite bricks (commonly used in steel smelting furnaces)—and castables, which require resistance to high temperatures, abrasion, and corrosion. Boric oxide is also an excellent solvent for metallic oxides at high temperatures. Dehybor® anhydrous borax and Neobor are also used as stabilizers and bonding agents in firebricks and castables.

Leather manufacturing

Both borax decahydrate and Optibor have been used in the leather industry since the latter half of the nineteenth century. The mild alkalinity of borax decahydrate and weak acidity of Optibor make them suitable for soaking hides and skins, stripping vegetable tans, and neutralizing chrome tans and limed pelts.

For more information about the use of borates in leather manufacturing, download Borates in Leather Manufacturing.

Nylon carpet dyeing

Aqueous borax decahydrate and Neobor solutions are known to exhibit relatively stable pH values at various concentrations and temperatures. For this reason, borax decahydrate is an excellent buffer and is recommended for pH control in the dyeing of nylon carpeting. The product offers the following advantages:

  • Reduction of monitoring and periodic bath adjustments
  • Better shade matching
  • Prevention of staining by jute backing
For more information about the use of borates in carpet dyeing, download Borax for pH Control in Nylon Carpet Dyeing.

Rio Tinto Borates is a global leader in the supply and science of borates - naturally-occurring minerals containing boron and other elements. Refined borates are essential nutrients for crops. We are 1,000 people serving 500 customers with over 1,700 delivery locations globally. We supply 30% of the world's need for refined borates from our world-class mine in Boron, California, about 100 miles east of Los Angeles.  Learn more about Rio Tinto

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