Patent Description:
Original equipment manufacturers (OEMs) especially in the automotive industry have rigorous odor specifications on all interior applications and heating and air conditioning units (HVAC).

The most common method to determine odor is VDA <NUM>, in which a sample of the material is heated in a small closed flask and then a qualified group of people perform an odor detection test. The ranking is made on a scale from <NUM> (no smell) to <NUM> (extremely high odor). Most OEMs have set the limits for odor at less than <NUM>, but it is almost impossible to reach this value with most commercial polypropylene compounds. Due to the high requirements for long term heat stability, UV resistance, scratch performance, surface quality, haptics and mechanical properties in automobiles many special additives and fillers are used which adversely contribute to smell.

Recently some special additives and methods have been developed to reduce the odor.

One type is referred to as "stripping" additives, which remove volatile organic substances during compounding, but these are not very efficient and have a very negative impact on long term heat stability, UV resistance and scratch performance, because also the content of additives needed for these properties are partially removed.

Another type of additive, known as "absorbers," reduce odor by absorbing molecules causing odor on big inner surfaces. However, these compounds are likewise inefficient and they negatively impact overall performance.

Odor reduction processes may involve the optimization of compounding and injection molding conditions by adjusting the manufacturing parameters. However, such processes have very limited efficacy and increase the cost for compounding and injection molding due to lower throughput and higher cycle times.

An additional consideration for OEMs relates to the prevention or reduction of fogging. The term "fogging" primarily refers to the evaporation of volatile components of polymers, textiles and leather, which are extensively used in the automotive industry.

High temperatures can cause the volatile components to evaporate and condense in fine droplets on the internal surfaces, including the windscreen, thereby impairing the driver's view and causing dangerous driving conditions.

At the same time the materials used become more brittle and harder as the volatile components evaporate resulting in material fatigue and premature aging.

Many methods for reducing fogging have been reported and are primarily aimed at lowering the surface tension of the substrate itself (see, e.g. JP Pat. <CIT> and <CIT>) or that of a water-absorptive compound, by treatment with a water-repellent compound, by nanostructuring the surface (see, e.g. <CIT>) or by warming the substrate itself.

All of these solutions require additional effort and cost such as the application of a coating on the finished article or additional steps in the production or installation of the article.

Thus there is a need to produce polyolefin compositions having improved odor and fogging properties that maintain suitable material properties and cost.

The present disclosure relates to a polyolefin composition according to claim <NUM> having reduced odor. Furthermore, the composition according to claim <NUM> has reduced fogging. It also provides a molded article according to claim <NUM>. Furthermore, the use of said composition in an injection molding process is claimed according to claim <NUM>.

The polyolefin composition of the present disclosure comprises: (A) at least one polyolefin;(B) from <NUM> to <NUM>% by weight of a filler selected from the group consisting of fibers, metallic flakes, glass flakes, milled glass, glass spheres, mineral fillers, barium sulfate, metal oxides and hydroxides, wood flour and mixtures thereof; and(C) from <NUM> to <NUM>% by weight of at least one cyclodextrin,the sum (A) + (B) + (C) being <NUM>. While multiple embodiments are disclosed, still other embodiments will become apparent to those skilled in the art from the following detailed description. As will be apparent, certain embodiments, as disclosed herein, are capable of modifications in various obvious aspects, all without departing from the spirit and scope of the claims as presented herein. Accordingly, the detailed description is to be incorporated as illustrative in nature and not restrictive.

Preferably, component (A) comprises at least one polypropylene. A polypropylene can be a propylene homopolymer, a heterophasic propylene copolymer, a random propylene copolymer or a mixture thereof, more preferably component (A) comprises at least one heterophasic propylene copolymer or at least one polypropylene homopolymer or a mixture thereof.

Heterophasic propylene copolymers comprise a matrix being either a propylene homopolymer or a random propylene copolymer in which an amorphous phase, which contains a propylene ethylene copolymer rubber (elastomer), is dispersed. Thus the polypropylene matrix contains dispersed inclusions not being part of the matrix and said inclusions contain the elastomer. The term inclusion indicates that the matrix and the inclusion form different phases within the heterophasic propylene. Further the heterophasic polypropylene may contain to some extent a crystalline polyethylene, which is a by-reaction product obtained by the preparation of the heterophasic propylene copolymer. Such crystalline polyethylene is present as inclusion of the amorphous phase due to thermodynamic reasons.

Cyclodextrins (CDs) are cyclic oligomers of glucose, which generally belong to the class of compounds known as oligosaccharides, formed by enzymes such as cyclodextrin glycosyltransferase (CGTase), which may contain <NUM>, <NUM>, or <NUM> glucose monomers joined by alpha-<NUM>,<NUM> linkages. These oligomers are commonly called α-cyclodextrin (α-CD), β-cyclodextrin (β-CD), and γ-cyclodextrin (γ-CD), respectively. Each glucose unit has three hydroxyl groups each at the <NUM>, <NUM>, and <NUM> positions. Hence, α-CD has <NUM> hydroxyls or <NUM> substitution sites available and may have a maximum degree of substitution (DS) of <NUM>. Similarly, β-CD and γ-CD have a maximum DS of <NUM> and <NUM>, respectively.

The most stable three-dimensional molecular configuration for these oligosaccharides is referred to as a "toroid," a doughnut or coil-like (torus) shape with the smaller and larger openings of the toroid presenting primary and secondary hydroxyl groups. The specific coupling of the glucose monomers gives the CD molecule a rigid, truncated conical molecular structure with a hollow interior of a specific volume.

This internal cavity, which is lipophilic, i.e. attractive to hydrocarbon materials when compared to the exterior surface, is a key structural feature of cyclodextrin, providing the ability to complex molecules (e.g., aromatics, alcohols, halides, hydrogen halides, carboxylic acids, esters, etc.). The complexed molecule must generally satisfy the size criterion of at least partially fitting into the cyclodextrin internal cavity for forming an inclusion complex.

Within the present disclosure, among cylodextrins, β-cyclodextrin, methylated β-cyclodextrin and a mixture between β-cyclodextrin and methylated β-cyclodextrin are preferred.

A filler (B) can also be comprised in the composition. The filler can be organic or inorganic.

Preferred are fibers, both organic and inorganic, and the other inorganic fillers (different from fibers), such as metallic flakes, glass flakes, milled glass, glass spheres and mineral fillers, like talc, calcium carbonate, mica, wollastonite or silicates in general, kaolin, barium sulfate, metal oxides and hydroxides such as magnesium hydroxide, or a mixture of these.

Fibers for the present compositions include fibers made of glass, metal, ceramic, graphite, and organic polymers such as polyesters and nylons, e.g., aramids, in filamentary form, all of which are commercially available.

Another suited filler is wood flour, alone or in mixture with the other types of fillers.

Preferred fillers are talc and glass fibers.

Glass fibers may be either milled or chopped short glass fibers or long glass fibers, or may be in the form of continuous filament fibers, although preference is given to using chopped glass fibers, also known as short glass fibers or chopped strands.

The composition can comprise a compatibilizer.

A compatibilizer is a component capable of improving the interfacial properties between fillers and polymers by reducing the interfacial tension between the two, while simultaneously reducing the agglomeration tendency of filler particles, thus improving their dispersion within the polymer matrix.

One type which can be used as compatibilizer are low molecular weight compounds having reactive polar groups which increases the polarity of polyolefin and are intended to react with the functionalized coating or sizing of the fillers, if present, to enhance the compatibility with the polyolefin itself. Suitable functionalizing groups for the fillers are, for example, silanes such as aminosilanes, epoxysilanes, amidosilanes and acrylosilanes, more preferably an aminosilane.

However, the compatibilizers preferably comprise a polymer modified (functionalized) with polar moieties and, optionally, a low molecular weight compound having reactive polar groups. Modified olefin polymers, in particular propylene homopolymers and copolymers, like copolymers of ethylene and propylene with optionally other alpha olefins, are most preferred. Modified polyethylene or polybutene can be used as well.

In terms of structure, the modified polymers are preferably selected from graft or block copolymers. In this context, preference is given to modified polymers containing groups deriving from polar compounds, in particular selected from acid anhydrides, carboxylic acids, carboxylic acid derivatives, primary and secondary amines, hydroxyl compounds, oxazoline and epoxides, and also ionic compounds.

Specific examples of the said polar compounds are unsaturated cyclic anhydrides and their aliphatic diesters, and the diacid derivatives. In particular, one can use maleic anhydride and compounds selected from C<NUM>-C<NUM> linear and branched dialkyl maleates, C<NUM>-C<NUM> linear and branched dialkyl fumarates, itaconic anhydride, C<NUM>-C<NUM> linear and branched itaconic acid dialkyl esters, maleic acid, fumaric acid, itaconic acid and mixtures thereof.

The compatibilizer can be used in an amount ranging from <NUM> up to <NUM> wt% with respect to the sum (A) + (B).

Preferably, the amount of groups deriving from polar compounds in the modified polymers ranges from <NUM> to <NUM>% by weight, more preferably from <NUM> to <NUM> wt%.

Preference is given to the use of a propylene polymer grafted with maleic anhydride as compatibilizer.

Preferably, if the filler is a glass fiber, the composition further comprises a compatibilizer, said compatibilizer being a propylene polymer grafted with maleic anhydride.

The composition of the present disclosure can be used for the production of injection molded articles, including but not limited to automotive articles, pipes and fibers for textile applications.

The following examples are given to illustrate the present disclosure without any limiting purpose.

The characterization data for the compositions of the disclosure were obtained according to the following methods:.

Determined according to ISO <NUM> (<NUM>, <NUM>), unless otherwise specified.

Determined according to ISO <NUM> (<NUM>, <NUM>).

Determined according to ISO <NUM>/<NUM>, <NUM> hour at <NUM>.

Determined according to ISO method <NUM> on rectangular specimens (<NUM> x <NUM> x <NUM>) from T-bars (ISO <NUM>-<NUM>, Type 1A).

Determined according to ISO <NUM>/1eU and /1eA on rectangular specimens (<NUM> x <NUM> x <NUM>) from T-bars (ISO <NUM>-<NUM>, Type 1A).

Determined on granules according to VDA <NUM>.

VOC amounts (highly and medium volatile compounds) were determined according to VDA <NUM>.

FOG (low volatile compounds) were determined according to VDA <NUM>.

Determined at <NUM> according to IEC <NUM>/<NUM> (VW <NUM>).

Determined according to DIN <NUM> with the gravimetric method (DIN <NUM>/B).

Odor was established according to VDA <NUM> by two panels of people. The rating is based on a scale from <NUM> (no smell) to <NUM> (extremely high odor).

Determined according to ISO <NUM>-<NUM> (<NUM>).

All compositions described in the examples were produced with a Krupp Werner & Pfleiderer/<NUM>, ZSK <NUM> twin-screw extruder (screw diameter: <NUM> x <NUM>, 36D; screw rotation speed of <NUM> rpm; melt temperature of <NUM>).

The composition of Example <NUM> was built up with the same components and amounts as Example <NUM>, except that the concentration of commercial polypropylene homopolymer (MFR = <NUM>/<NUM>) was <NUM> wt%, and the CAVAMAX® W7 β-cyclodextrin concentration was <NUM> wt%.

The composition of Example <NUM> was built up with the same components and amounts as Example <NUM>, except that the cyclodextrin used was CAVASOL® W7 M methyl-β-cyclodextrin from Wacker Chemie.

The composition of Example <NUM> was built up with the same components and amounts as Example <NUM>, except that the concentration of commercial polypropylene homopolymer (MFR = <NUM>/<NUM>) was <NUM> wt%, and the CAVASOL® W7 M methyl-β-cyclodextrin concentration was <NUM> wt%.

The composition of Example <NUM> was built up with the same components and amounts as Example <NUM> except that the concentration of the commercial polypropylene homopolymer (MFR = <NUM>/<NUM>) was <NUM> wt% and, instead of <NUM> wt% of CAVASOL W7 M methyl-β-cyclodextrin, <NUM> wt% of CAVAMAX W7 β-cyclodextrin and <NUM> wt% of CAVASOL W7 M methyl-β-cyclodextrin were used.

The composition of Comparative Example <NUM> was built up with the same components and amounts as Example <NUM> except that the concentration of the commercial polypropylene homopolymer (MFR = <NUM>/<NUM>) was <NUM> wt%, and no cyclodextrins were present.

The compositions of Examples <NUM>-<NUM> and Comparative Example <NUM> are reported in Table <NUM>.

The properties of Examples <NUM>-<NUM> and Comparative Example <NUM> are reported in Table <NUM>.

The formulations comprising talc as a reinforcing filler and <NUM> wt% or <NUM> wt% of β-cyclodextrin (Example <NUM> and <NUM>), <NUM> wt% or <NUM> wt% of methyl- β-cyclodextrin (Example <NUM> and <NUM>) and the formulation with <NUM> wt% each of β-cyclodextrin and methylated β-cyclodextrin (Example <NUM>) showed a significant reduction of odor compared to the formulation without cyclodextrins (Comparative Example <NUM>).

The composition of Comparative Example <NUM> was built up with the same components and amounts as Example <NUM> except that the commercial polypropylene homopolymer (PP homo <NUM>) concentration was <NUM> wt%, and no cyclodextrins were present.

The compositions of Example <NUM> and Comparative Example <NUM> are reported in Table <NUM>.

Properties of Example <NUM> and Comparative Example <NUM> are reported in Table <NUM>.

The formulation comprising glass fibers as a reinforcing filler and <NUM>% by weight of β-cyclodextrin (Example <NUM>) showed a significant reduction of odor and fogging in comparison with the formulation without cyclodextrins (Comparative Example <NUM>).

Composition of Example <NUM> was built up with the same components and amounts of Example <NUM> except that that the cyclodextrin used was CAVASOL® W7 M methyl-β-cyclodextrin (Wacker Chemie).

The composition of Comparative Example <NUM> was built up with the same components and amounts as Example <NUM> except that the commercial polypropylene homopolymer (PP homo <NUM>) was <NUM> wt%, and no cyclodextrins were present.

Compositions of Examples <NUM> and <NUM> and Comparative Example <NUM> are reported in Table <NUM>.

Properties of Examples <NUM> and <NUM> and Comparative Example <NUM> are summoned up in Table <NUM>.

Claim 1:
Polyolefin composition comprising:
(A) at least one polyolefin;
(B) from <NUM> to <NUM>% by weight of a filler selected from the group consisting of fibers, metallic flakes, glass flakes, milled glass, glass spheres, mineral fillers, barium sulfate, metal oxides and hydroxides, wood flour and mixtures thereof; and
(C) from <NUM> to <NUM>% by weight of at least one cyclodextrin,
the sum (A) + (B) + (C) being <NUM>.