Chemistry-related aspects in the manufacture of artificial fibres, filaments and similar. It also covers - the chemical treatment of fibres and filaments during their production, e.g. before winding,

Apparatus specially adapted for the manufacture of carbon filaments is also covered.

Many documents in the field disclose features related to both the mechanical (D01D) and the chemical (D01F) aspect of fibre manufacture. Two cases can be envisaged:

a) When a document is concerned with mechanical aspects but mentions specific polymers, classification should always be given in D01D and classification may be added in D01F when the chemical aspects are relevant or non-usual polymers or additives are used. No D01F classification should be given when a long list of polymers is mentioned, even when in the claims.

b) When a document is concerned with chemical aspects but mentions specific techniques (e.g. melt-blowing, electrospinning) classification should always be given in D01F and classification may be added in D01D when the specific technique plays an important role. No D01D classification should be given when several unrelated techniques are mentioned, even when in the claims.

Attention should be paid when blends or additives are used. These cases are classified in different subgroups and sometimes there is an overlap. As a general rule, additives are characterised by their function (e.g. stabilizer, pigment), whilst polymer blends have different properties compared to the single substances.

In the case where classification is given under D01F 1/00 a corresponding group under D01F 6/00 should be given when a specific polymer is used. However, no classification should be given under D01F 6/00 when a long list of polymers is mentioned.

The table below is an example concerning polyethylene:

Addition of additives to the spinning solution or melt.

D01F 1/00 covers the chemical nature of the additive, whereas the method of adding the additive, that would be considered to be a mechanical feature, is classified in D01D 1/065.

In the case where classification is given under D01F 1/00 a corresponding group under D01F 6/00 should be given when a specific polymer is used. However, no classification should be given under D01F 6/00 when a long list of polymers is mentioned.

When an additive is used in the spinning solution or in the melt, and this additive has none of the specific properties mentioned in the subgroups of D01F 1/00, then two cases are envisaged:

when the additive has an effect on the fibre production process (e.g. lubricant, viscosity modifier), the group D01F 1/02 should be given;

when the additive has an effect on the final properties of the fibre (e.g. additives for improving the tensile strength), the group D01F 1/10 should be given.

Please note that the composition of the spinning solution of viscose is dealt with in D01F 2/08 and subgroups.

Under D01F 1/09, when an intrinsically electrically conductive additive (e.g. carbon nanotubes) is added for a different purpose (e.g. tensile strength), only the classification related to the desired function should be allocated.

Also covers addition of additives to make antistatic fibres/filaments.

Artificial monocomponent fibres or the like of cellulose or its derivatives .

D01F 2/00 only covers the production of cellulosic fibres. Fibres from other carbohydrates (e.g. starch, hemicellulose, chitosan, dextran, hyaluronan) are classified in D01F 9/00.

Fibres spun from amine oxide solutions (e.g. lyocell) are classified in D01F 2/00.

Fibres spun from solutions of ionic liquids.

Addition of substances to the spinning solution or bath, these substances having an effect on the solution, on the bath or on the final fibre.

Cellulose carbamate fibres.

Monocomponent fibres or the like of proteins.

When a polyaminoacid or a polypeptide is obtained synthetically, classification in D01F 6/68 should be given. Fibres from natural proteins are classified in D01F 4/00, even when the protein has been chemically modified.

Monocomponent fibres or the like of synthetic polymers.

This group is divided in two main sections based on the type of polymer used. The first part relates to polyaddition polymers and the second part to polycondensation polymers. In turn, for each type of polymers a distinction is made between homopolymers, copolymers and blended polymers. When a document covers both homo- and copolymers the homopolymer group is always allocated, and the copolymer group is only allocated when specific information is given about the copolymer (e.g. type and amount of comonomers).

D01F 6/38 vs. D01F 6/40

All fibres comprising 35-85% of acrylonitrile are classified in D01F 6/40 even if the fibres are not defined as modacrylic. If an overlap exists on the amount of acrylonitrile both classifications should be allocated.

D01F 6/70

Although the polyurethanes used to make fibres are normally copolymers, elastic polyurethane fibres are always classified in this subgroup

Polyolefins in general.

Polypropene.

Polyvinylpyrrolidone fibres.

Polydienes

Polyketone fibres.

Poly(lactic acid) fibres, including the polymers of racemic mixtures of D- and L-acid.

Polybenzazole/polybenzoxazole fibres.

Polyaniline fibres.

Multicomponent, i.e. conjugated, fibres or the like such as core-sheath, side-by-side, islands-in the sea, etc.

Documents concerning multicomponent fibres should be classified under D01F 8/00 if the chemical aspects are important (e.g. the materials used) and in D01D 5/30 - D01D 5/36 when the mechanical aspects are important (e.g. the spinneret or the method used).

The coating of fibres or filaments is classified in D01F 13/00 (if the coating happens during production, covering chemical aspects), D01D 11/06 (if the coating happens during production, covering mechanical aspects), D06M (if the coating happens after production, covering chemical aspects), or D02J (if the coating happens after production, covering mechanical aspects).

Man-made filaments or the like of other substances that are not comprised in any of the above groups.

Also covers apparatus for manufacturing carbon fibres.

Carbon nanofibers vs nanotubes:

Carbon nanotubes are classified in C01B 32/15. However, sometimes a document uses the term "nanofiber" as a broad term including nanotubes. In these cases, the description should be checked, and classification under D01F should not be given if the document appears to actually relate to nanotubes only. Yarns of carbon nanotubes/nanofibres are classified under D01F 9/00 when the chemical aspects are important, and under D02G 3/00 when the mechanical aspects are important. In case of doubt, classification under both groups should be given.

Apparatus for manufacturing vapor-grown carbon fibres.

Apparatus for manufacturing carbon fibres obtained by carbonization of organic filaments.

Chemical treatment of filaments and the like during their manufacture, i.e. during a continuous production process before the filaments have been collected.

Chemical treatment is not limited to reactive treatments, but is considered to encompass any treatment with a chemical substance, e.g. coating with a solution.

Recovery of starting material, waste material or solvents during the manufacture of artificial filaments or the like.