On June 16, 2011, the US Patent & Trademark Office published a patent application from Apple that reveals a newly advanced halogen-free flame retardant material that is likely to be integrated into the manufacturing of Apple products like keyboards, mice, iPods, the iPad, cabling and more. Apple's invention provides for a halogen free resin composition that includes at least one thermoplastic polymer, an inorganic filler and a flame retardant additive that is described as being "self-fire extinguishable."
The Problem to Solve
It has been estimated that about 10% of fires are caused by electrical faults of wiring and electrical equipment, and that these fires account for 19% of fire-related injuries. Some plastics are inherently resistant to fire, such as polyvinylchloride (PVC). However, PVC is not suitable for many electronics applications. Only about 12% of plastics used today contain flame retardants. An increased use of flame retardants would improve the safety of electrical wiring and electronic devices, and therefore reduce the number of fires caused by electronic devices.
Halogenated flame retardants have been found to be effective in many plastics. However, environmental and health concerns have caused halogenated flame retardants to be less desirable for electronic devices, and they are being increasingly regulated.
A wide variety of flame retardant resin compositions have been developed to ensuring safety against fire, including halogen free flame retardant resin compositions. Generally, halogen free flame resisting resin compositions contain inorganic fillers, such as aluminum hydroxide or magnesium hydroxide. The amount of the inorganic filler required to obtain sufficiently high flame resisting effect is generally 30 to 70% by weight based of the composition. However, a synthetic resin composition containing such high contents of inorganic filler generally do not exhibit suitable physical characteristics, such as well-balanced strength, resulting in brittle products with poor processability. Accordingly, there is a need for new halogen-free flame retardants, as well as new halogen-free plastics and resin materials.
Apple's Solution
Apple's proposed invention provides halogen-free flame retardants, resins that include halogen free flame retardants, and plastic components made from such materials. In some embodiments, the invention relates to a composite resin molded article having excellent flame retardancy, electric insulation properties, and crack resistance, and produces only negligible amounts of toxic substances during incineration, if any at all.
Accordingly, the invention provides a halogen free resin composition that includes at least one thermoplastic polymer; an inorganic filler; and a flame retardant additive, wherein the flame retardant additive comprises an alkali metal nitrite; an alkaline earth metal nitrite; an alkali metal nitride; an alkaline earth metal nitride; an alkali metal borate; an alkaline earth metal borate; an alkali metal silicide; an alkaline earth metal silicide; an alkali metal silicate; an alkaline earth metal silicate; or a combination thereof.
The invention further provides a computing system, input device, or computer component comprising any of the compositions described above or herein. For example, a computing system could include at least one component selected from the group consisting essentially of, a housing, an input device, and a cable, wherein the component includes a halogen free resin, that includes at least one thermoplastic polymer; an inorganic filler; and a flame retardant additive, wherein the flame retardant additive comprises an alkali metal nitrite; an alkaline earth metal nitrite; an alkali metal nitride; an alkaline earth metal nitride; an alkali metal borate; an alkaline earth metal borate; an alkali metal silicide; an alkaline earth metal silicide; an alkali metal silicate; an alkaline earth metal silicate; or a combination thereof.
In some embodiments, a flame retardant resin is provided that does not include carbon black. The resins are therefore widely applicable to the fields where colored products are desirable, such as products where appearance has commercial significance. Examples of such products include personal electronic devices, such as personal computers, laptop computers, cell phones, personal digital assistants, tablets, electronic games, and the like.
The invention also relates to a self-fire extinguishable, halogen-free and flame resisting synthetic resin composition.
Today's published patent application from Apple was originally filed in Q4 2009 by the sole inventor Jean Lee. See patent application 20110144244 for more details.