Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
1998-04-21
2002-05-28
Seidleck, James J. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S310000, C524S312000, C524S318000, C524S320000, C524S322000
Reexamination Certificate
active
06395812
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a polymer composition comprising a polymer and an anti-static composition. In particular, the present invention relates to a polymer composition comprising a polymer and an anti-static composition, wherein the anti-static composition comprises at least two components having different properties relative to each other. The polymer composition may be used in packaging applications.
BACKGROUND OF THE INVENTION
Polymers have an extremely wide field of applications. In the food industry the use of polymers for the manufacture of food containers is important. In particular, polymers may be used to manufacture small food containers in which food products may be stored.
After the manufacture of food containers and the like, it is known that static charge may build up on the polymer surface. This static charge attracts dust and other fine particles. If such particles settle on a polymeric food container or similar packaging the container will appear dirty and will be less appealing to purchasers of the food. There is also the possibility of food contamination.
To overcome the problems of static build up on polymers in the food and other industries, anti-static (antistat) compositions have been provided. A good antistat composition dissipates or reduces static charge on a polymer over a long period. In the field of packaging, it is desirable that the antistat properties remain for the life time of the packaged product.
Antistat protection is typically obtained by incorporating an anti-static composition or compound into a polymer. The anti-static composition or compound may be incorporated into the polymer during the processing or production of the polymer, for example during the injection moulding of the polymer.
Conventional anti-static compositions of the prior art are distilled monoglycerides or mono-diglycerides derived from vegetable oils e.g. soya bean and rape seed, and animal fats. These anti-static compositions have been particularly recommended for incorporation into polypropylene and, in addition, have been particularly recommended for incorporation into injection moulded polymers.
Because of the derivation of the above conventional anti-static compositions they most commonly have a fatty acid profile that is a blend of palmitic (C
16
) acid and stearic (C
18
) acid.
A typical prior art teaching is provided by JP-A-01263135 which discloses polyolefins containing anti-static agents composed of ≧2 A
1
OCH
2
CH(OA
2
)—CH
2
OA
3
, wherein A
1-3
=H,COR; R═C
9-21
alkyl or alkenyl, ≧1 of A
1-3
is COR.
JP-A-08134289, JP-A-63213538, JP-A-63056545 and JP-A-07331230 disclose mixtures of glycerides and amine based compounds. These documents teach that these compositions have anti-static properties. To achieve their anti-static properties these compositions require the presence of the amine based compound. Legislation and consumer pressure provides that such amine based compounds should be present at low levels in food applications, or, if possible, completely excluded. However, the above prior art documents require the presence of amine based compounds to exhibit an anti-static effect.
The prior art anti-static compositions may provide acceptable results in some applications. However, in demanding applications, for example in the use of block copolymer polypropylene, the prior art anti-static compositions do not provide reliable results.
Furthermore, prior art antistats may also be disadvantageous because they may be incompatible with the polymer into which they are incorporated or with which they may be contacted. For example, the electronics industry commonly uses polycarbonates as a substrate and/or carrier for electronic components. However, nitrogen based or ionic anti-static compounds, which are commonly used, may corrode polycarbonate materials.
OBJECTS AND SUMMARY OF THE INVENTION
The present invention addresses the problems of the prior art anti-static compounds and compositions, namely their poor performance in use with some polymers and/or in some applications.
The present invention aims to overcome the problems of the prior art.
According to a first aspect of the present invention there is provided use of an anti-static composition for the manufacture of a polymer composition, e.g., the present invention can provide an anti-static composition, as well as a polymer composition including the anti-static composition; wherein the anti-static composition comprises at least a first component (“composition I”) and a second component (“composition II”); wherein the first or second component inhibits the crystallisation of the other respective component; wherein at least the other respective component is an anti-static component; and wherein the anti-static composition is contacted with a polymer to form the polymer composition; with the proviso that if the anti-static composition consists solely of composition I and composition II, the anti-static composition is prepared by any one of: (i) integrated blending; or (ii) dry blending. Thus, the present invention also provides a method for preparing an anti-static composition comprising integrated or dry blending of compositions I and II, as well as a method for preparing the polymer composition comprising contacting the anti-static composition with the polymer to form the polymer composition.
Therefore, according to a second aspect of the present invention there is provided a method of preparing a polymer composition comprising the steps of a) providing an anti- static composition comprising at least a first component and a second component; wherein the first or second component inhibits the crystallisation of the other respective component; and wherein at least the other respective component is an anti-static component; and b) contacting the anti-static composition with a polymer to form the polymer composition; with the proviso that if the anti-static composition consists solely of composition I and composition II, the anti-static composition is prepared by any one of: (i) integrated blending; (ii) dry blending.
According to a third aspect of the present invention there is provided a polymer composition comprising: a polymer; and an anti-static composition; wherein the anti-static composition comprises at least a first component and a second component; wherein the first or second component inhibits the crystallisation of the other respective component; and wherein at least the other respective component is an anti-static component; with the proviso that if the anti-static composition consists solely of composition I and composition II the anti-static composition is prepared by any one of: (i) integrated blending; (ii) dry blending.
According to a fourth aspect of the present invention there is provided an integrated pellet comprising a polymer and an inventive anti-static composition; or, comprising an inventive polymer composition.
According to a fifth aspect of the invention, there is provided a container comprising an inventive polymer composition or comprising a polymer composition prepared in accordance with the methods or uses described herein.
These and other objectives and embodiments are disclosed or are obvious from and encompassed by the following Detailed Description.
DETAILED DESCRIPTION
As discussed above, the present invention entails, for instance, according to a first aspect, use of an anti-static composition for the manufacture of a polymer composition, e.g., the present invention can provide an anti-static composition, as well as a polymer composition including the anti-static composition; wherein the anti-static composition comprises at least a first component (“composition I”) and a second component (“composition II”); wherein the first or second component inhibits the crystallisation of the other respective component; wherein at least the other respective component is an anti-static component; and wherein the anti-static composition is contacted with a polymer to form the polymer composition; with the proviso that if the anti-static com
Danisco A/S
Frommer Lawrence and Haug LLP
Kowalski Thomas J.
Megerditchian Samuel H.
Rajguru U. K.
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