Stock material or miscellaneous articles – Hollow or container type article – Polymer or resin containing
Reexamination Certificate
1996-12-31
2001-04-17
Short, Patricia A. (Department: 1712)
Stock material or miscellaneous articles
Hollow or container type article
Polymer or resin containing
C428S036910, C428S423100, C428S423300, C428S423500, C428S423700, C428S424700, C428S474400, C428S474700, C428S475200, C428S476300, C428S480000, C428S522000, C525S064000, C525S066000, C525S09200D, C525S131000, C525S167000, C525S173000, C525S183000, C036S014000
Reexamination Certificate
active
06217961
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to composite articles including thermoplastic materials which are adherent by themselves to a particular class of thermoplastic elastomers which can be obtained by a process of dynamic vulcanization of rubbers dispersed in the form of fine particles in a thermoplastic matrix (called TPV in what follows); that is to say that the articles of the invention include a thermoplastic and a TPV, these TPVs being also called rubber/thermoplastic blends.
BACKGROUND OF THE INVENTION
The development of technical components fulfilling a number of functions increasingly requires the assembly of materials covering the widest possible spectrum of mechanical and physicochemical properties. The present invention relates to composites assembled without resort to adhesives, by using well-known fabricating processes such as overmoulding, two-material injection moulding and coextrusion.
European Application EP 550346 describes a process for obtaining, and articles consisting of, vulcanized rubbers and of polymers containing polyamide blocks which are used in combination without adhesives. It thus becomes possible to combine in the same object the specific properties of rubbers (small residual deformation on compression, low hardness, resistance to abrasion, to hot oils etc.) and the specific properties of polyetheresteramides (flexibility, good mechanical properties, fatigue resistance etc.).
However, the processes employed for producing these objects are partly those of the rubber industry, characterized by long cycle times (typically 10 minutes) and high processing costs.
The objective of the present invention is to obtain composite articles which have the same multiple functions by replacing the part consisting of vulcanized rubber with a thermoplastic rubber (TPV) and by resorting to thermoplastic fabrication processes. It is well known that TPVs are materials which have properties very closely related to vulcanized rubbers while retaining the easy processability of thermoplastics (see the review paper describing these materials by A. Coran et al. in “Thermoplastic Elastomers”, MacMillan Publishing 1987).
Patent EP 231674 describes blends consisting of copolymers containing polyamide blocks and nonfunctionalized nitrile rubbers.
Japanese Application JP 63-81158 describes compositions based on polyetheresteramides and on various rubbers which are at least partially crosslinked, the two components being in a ratio of 1:1.
However, in the present invention the advantage of the vulcanization of the rubber lies in the possibility of creating a thermoplastic matrix even if the predominant component is the rubber. The advantage is also that of having a TPV formed by a thermoplastic matrix in which the vulcanized rubber is dispersed. This is valid even if the thermoplastic is in a minority and the rubber in a majority.
In the examples provided by the Japanese Applicant there is only a partial vulcanization of the rubber, whereas an advanced vulcanization (from 50 to 90%) makes it possible to obtain improved properties such as tensile strength, abrasion resistance, better tenacity and residual deformation on compression.
SUMMARY OF THE INVENTION
The present invention provides a composite material that comprises a thermoplastic material and a thermoplastic rubber blend which is capable of adhering to said thermoplastic material, wherein said thermoplastic rubber blend comprises (i) at least one functionalized and vulcanizable elastomer and (ii) at least one block copolymer comprising polyether or amorphous polyester blocks.
This composite material is used to make a composition of matter comprising a block copolymer containing polyether or amorphous polyester blocks as a matrix and further comprising nodules of functionalized and vulcanized rubber distributed throughout said composition of matter within said matrix. The composition of matter may be prepared by a process which comprises mixing (i) a formulation comprising at least one functionalized and vulcanizable elastomer, a vulcanizing agent, and, optionally, fillers and plasticizers and (ii) at least one block copolymer comprising polyether or amorphous polyester blocks, the mixing intimately dispersing elastomer (i) in molten block copolymer (ii) and being carried out at a temperature sufficient both to melt said block copolymer and to vulcanize said elastomer, said mixing being carried out for a period of time substantially less than that which would result in reaction of all of the functional groups in said functionalized elastomer.
The present invention further provides a method for the manufacture of the composite material which comprises combining the thermoplastic rubber blend and the thermoplastic material by a process selected from the group consisting of coinjection, overmolding, and coextrusion.
The present invention includes a composite wherein
the thermoplastic material is selected from the group consisting of polyamides, thermoplastic elastomers containing polyamide blocks, thermoplastic elastomers containing polyester blocks, semicrystalline polyesters, polyurethanes, and poly(vinyl chlorides) and
the thermoplastic rubber blend comprises
(i) at least one polyetheresteramide elastomer functionalized with a member of the group consisting of carboxylic acid, carboxylic anhydride, carboxylate salt, carboxylate ester, epoxy, amino, and halo groups and
(ii) at least one block copolymer comprising a rigid portion formed of polyurethane blocks and a flexible part formed of polyether or amorphous polyester blocks.
The endproducts of the present invention are articles of manufacture comprising thermoplastic materials and thermoplastic rubber blends capable of adhering to the thermoplastic material, wherein the thermoplastic rubber blends comprise (i) at least one functionalized and vulcanizable elastomer and (ii) at least one block copolymer comprising polyether or amorphous polyester blocks. The articles of manufacture may be configured as footware soles, coextruded sections, coextruded pipe in which the thermoplastic material and thermoplastic rubber blend is overmolded around pipe that has an outer layer made of polyamide, conveyor belts, and transmission belts.
The TPVs employed for producing the composite articles of the invention include:
at least one functionalized and vulcanizable elastomer;
at least one block copolymer containing polyether or amorphous polyester blocks.
It has been found that these TPV compositions can be used in combination with various thermoplastics using processes such as coinjection, overmoulding or coextrusion, that is to say essentially without adhesive.
The cohesion at the interface between these two materials is generally higher than the tensile strength of each of the 2 materials. However, it would not constitute a departure from the scope of the invention to add an adhesive onto all or part of the surface of contact.
The quantity of vulcanisable elastomer may be from 20 to 90% by weight of the TPV, that is to say of the vulcanizable elastomer block copolymer combination.
With regard to the block copolymer forming the TPV, its polyether or amorphous polyester blocks form its flexible part and polyamide, polyester or polyurethane semicrystalline blocks can form its rigid part.
By way of example there may be mentioned polyetherurethanes formed by the reaction of amorphous polyesterdiols with polyisocyanates, and polyetherurethanes formed by the reaction of polyetherdiols with polyisocyanates.
The block copolymer may include polyether units and polyester units. These are, for example, polyether blocks and polyester blocks. These products are known under the name of elastomeric polyesters and are thermoplastic.
The polyethers are, for example, polyethylene glycol (PEG), polypropylene glycol (PPG) or polytetramethylene glycol (PTMG).
The molecular mass {overscore (M)}n of these polyethers may be between 250 and 6,000.
These polyethers condense with at least one dicarboxylic acid to form the flexible blocks of the elastomeric esters.
The polyester blocks result, for exam
Alex Patrick
Cerf Martine
Dousson Christian
Hert Marius
Altofina
Pennie & Edmonds LLP
Short Patricia A.
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