Cooperative Patent Classification

CPC Definition - Subclass B29K

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Last Updated Version: 2018.01
Definition statement

This place covers:

This subclass constitutes an indexing scheme associated with subclasses B29B, B29C or B29D, which provides information concerning moulding materials (composition, condition, form or state) or compositions for reinforcements, fillers and preformed parts, e.g. as inserts.

Moulding materials include the materials being applied in the processes as provided in the subclass B29B, e.g. the making of granules, the recovery of plastics.

This subclass provides further an indexing scheme B29K 2995/00 concerning the properties of moulding materials, reinforcements, fillers, preformed parts and moulds.

The following polymeric substances as moulding material, reinforcement, filler and/or preformed parts:

  • cellulose, cellulose derivatives and rubbers;
  • polyalkenes, vinyl-polymers, polymers of unsaturated acids, polymers of unsaturated cyclic compounds having no unsaturated aliphatic groups;
  • polyacetals, condensation polymers of aldehydes or ketones, epoxy resins, polyesters, polycarbonates, polyethers, polyureas or polyurethanes, polyamides;
  • other polymers having oxygen, nitrogen, sulfur, silicon or others in the main chain;
  • specific polymers obtained by polymerisation involving carbon-to-carbon unsaturated bonds, polycondensation or polyaddition;
  • waxes (except as reinforcement), bituminous materials, resin-bonded materials; and
  • other specified or unspecified macromolecular materials.

The following substances as reinforcement, filler and/or preformed parts:

  • metals, their alloys or their compounds, elements other than metals, other inorganic materials, other natural products or their composites.

Condition, form or state of moulded plastics or substances in a plastic state.

Relationships with other classification places

The Indexing Codes B29K follow the same structure as C08L, e.g. C08L 71/00 refers to the composition of polyethers as such. B29K 2071/00 refers to the use of polyethers as moulding material, B29K 2271/00 refers to the use of polyethers as reinforcement, B29K 2471/00 refers to the use of polyethers as filler, B29K 2671/00 refers to the use of polyethers as preformed parts, e.g. inserts and B29K 2871/00 refers to the use of polyethers as mould material

In the same way, for compositions of polyureas and polyurethanes as defined in C08L 75/00, corresponding Indexing Codes B29K 2075/00, B29K 2275/00, B29K 2475/00, B29K 2675/00 and B29K 2875/00 are provided.

Special rules of classification

The indexing codes provided in this subclass can only be applied in association with classification symbols of the subclasses B29B, B29C or B29D.

The classifier should therefore identify additional information that is neither implicit from the allocated B29B, B29C or B29D classification symbols, nor implicit from the applied technology as such. The mere identification of materials or their properties by extensive lists does not necessarily imply that this information is useful for search purposes. The selection of non-obvious materials or the application of materials or the selection of material properties, which have some relation with the alleged invention are considered to be useful for search and should be identified by the allocation of the corresponding Indexing Code or codes provided in B29K, as long as they are not implicit from the allocated B29B, B29C or B29D classification symbols or from the applied technology as such.

Example : the manufacture by resin transfer moulding of a wind turbine blade is described using fibres of carbon, glass or aramid and a thermoplastic matrix, such as PE, PVC, PP, PS or PEEK. In this case, the Indexing Code for fibres will give no information of use for searching, the applied technology, namely shaping composites, implies already the use of a reinforcement. Glass, carbon and aramid fibres are further the main used fibres in composite material. The mere mention of these three types of fibres as alternative in an application is, therefore, not considered as additional information useful for search purposes, and the Indexing Codes are not required. The list of matrix material also consists of common polymers which have no particular claimed effects and/or characteristics in regards to the manufactured product. The allocation of the general Indexing Code for thermoplastic materials B29K 2101/12 is sufficient.

Reference is further made to the special rule of classification in the field of B29B 17/00.

Glossary of terms

In this place, the following terms or expressions are used with the meaning indicated:


a) natural or conjugated diene-based rubber (b) rubber in general (for a specific rubber, other than a natural rubber or a conjugated diene-based rubber)


Part of a polymer composed by a same monomeric unity


Structure in the form of fibres, wires, rods, bars, sections, plates or blocks, which improves the strength of an article


Relatively inert substance in the form of particles, powder, beads, flakes or spheres, which improves the physical properties or increases the bulk or weight of an article

Preformed part

Any material, being completely shaped to have a determined form and which is not used as a reinforcement, e.g. wires or nets forced only into the surface of an article


Preformed part incorporated in an article during moulding; the insert can be incorporated completely or partially, e.g. only its edge or its surface