Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2000-01-26
2002-11-19
Cain, Edward J. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S012000, C524S015000, C524S044000
Reexamination Certificate
active
06482875
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a thermoplastic composite material containing an organic fibrous material or a mixture of two or more organic fibrous materials and a thermoplastic binder. The invention also relates to a process for producing the thermoplastic composite material and to the use of the composite material for coating surfaces of objects and to the objects thus coated. The invention also relates to an adhesive for bonding the composite material to the object to be coated.
2. Discussion of the Related Art
Composite materials are materials which are formed by incorporating a base material, for example in the form of fibers, in a second material (the matrix). Certain properties (for example mechanical properties, surface properties or certain behavior towards external influences) of the incorporated material are utilized for the composite material. The base material may vary widely in its quantity ratio to the matrix surrounding it. Thus, the percentage matrix content of wood-based materials, which include for example the known presspahn boards, is generally only 10 to 15%. By contrast, the percentage matrix content of fiber-reinforced plastics, for example glass fiber-reinforced plastics, can be significantly higher, for example more than 70% or even more than 80%.
In many cases, it is possible by suitably selecting the base material and the matrix to impart to the composite material certain properties of the base material which are paired with certain properties of the matrix. For example, the use of glass or natural fibers in thermosets can cause the tensile strength of the fibers to be transferred to the plastic matrix which, in turn, contributes further advantages to the composite material in regard to shaping, dimensional stability and processability.
In many cases, the object of making composite materials is to produce from by- products accumulating in the processing of a certain base material a material which possesses characteristic properties of that base material. The corresponding composite material may then generally be used at least as a substitute for the base material and thus provides for the “substance-related” utilization of the base material waste or by-products. This is the case, for example, with the utilization of wood waste in presspahn boards. Another example of the substance-related utilization of waste products is the processing of cutting and stamping waste from the manufacture of leather and shoes to leather fiber materials.
Leather waste can be reduced to fibers and can then be processed to leather fiber materials (LEFAs). LEFAs are generally single-layer materials of leather fibers and binders. Even at the end of the thirties, LEFA boards were being used in the shoe industry, for example for the production of counters, insoles and inner soles, slipper soles, heels and welts. LEFA materials were also used to a small extent for industrial leather seals.
Besides such properties as flexibility and durability which qualify leather for use in the shoe industry and in the leather goods industry, leather is being increasingly used in other areas where the decorative features of leather are predominant. However, it has hitherto been difficult or even impossible to use leather as a surface material for furniture fronts, wall and ceiling panels or other consumer goods. In particular, it was particularly difficult to use leather as a surface material for objects with a three-dimensional relief structure.
Since leather does not have any thermoplastic properties, it can only be used to a limited extent as a surface coating material. In particular, it is difficult to provide varying three-dimensional relief structures with a smooth leather surface by an economical process.
Such economical processes for coating relief-like surfaces of moldings are known, for example, from the film coating industry. In this case, a molding (object) is generally coated with a thermoplastic film by heating the molding and the film to a temperature above the flow transition limit of the plastic film and suitably drawing the film (for example by applying a vacuum between the molding and the plastic film) onto the molding (thermoforming). In general, an adhesive establishes a permanent bond between the plastic film and the molding.
However, a process such as this, which can be efficiently carried out with machine assistance, requires a thermoplastic film as the coating material. Hitherto, however, it has not been possible to finish leather-like substitute materials, for example LEFAs, in such a way that, on the one hand, they show the thermoplastic properties which are required for use in thermoforming processes but, on the hand, still have leather-like surface properties.
Accordingly, the problem addressed by the present invention was to provide a composite material which would largely exhibit the properties of the natural fibers used as the base material, but which on the other hand would be suitable for use in modern thermoforming processes by virtue of its thermoplastic properties. Another problem addressed by the present invention was to provide an adhesive with which the thermoplastic composite material could be firmly and durably bonded to a number of surfaces in the course of machine processing.
DESCRIPTION OF THE INVENTION
It has now been found that a thermoplastic composite material containing an organic fibrous material or a mixture of two or more organic fibrous materials and a thermoplastic binder as the matrix material can be obtained providing polyacrylates of at least one aqueous anionic polyacrylate dispersion and at least one aqueous cationic polyacrylate dispersion are used as the matrix material. The thermoplastic composite material obtainable in this way has a flow transition limit of about 70 to about 130° C. and is thus suitable for economical processing in surface coating.
Accordingly, the present invention relates to a thermoplastic composite material containing
a) at least 15% by weight of an organic fibrous material or of a mixture of two or more organic fibrous materials as component A and
b) at least 15% by weight of a thermoplastic binder as component B,
the binder containing at least two different polyacrylates and the thermoplastic composite material having a flow transition limit of 70° C. to 130° C.
Component A of the thermoplastic composite material may be any organic fibrous material which provides the thermoplastic composite material with the properties required by the user, for example a certain appearance or a certain feel. Organic fibrous materials in the context of the present invention are understood to be both naturally obtained or naturally obtainable fibers and synthetic fibers providing they have an “organic base”. Accordingly, organic fibrous materials do not include, for example, such fibers as asbestos, glass fibers or carbon fibers.
In addition, no distinction is made in the present specification between materials which occur naturally in fibrous form and materials which have to be given a fibrous structure by a certain treatment step. In addition, among the natural materials, both vegetable and animal organic fibrous materials are suitable for the purposes of the invention.
Synthetic fibers, vegetable fibers or animal fibers are normally used for the purposes of the invention.
Suitable natural fibers include, for example, animal fibers, such as wool, hair or silk. Other suitable natural fibers are vegetable fibers, for example cotton, kapok, flax, hemp, jute, kenaf, ramie, broom, abaca, coconut or sisal. Suitable synthetic fibers of natural polymers are cupro fibers, viscose fibers, modal fibers, acetate fibers, triacetate fibers and protein fibers or alginate fibers or mixtures of two or more of the fibers mentioned.
Suitable fibers of synthetic polymers are, for example, polyacrylic, modacrylic, polyvinyl chloride, fluorine-containing polymer fibers, poly-ethylene, polypropylene, vinyl acetate, polyacrylonitrile, polyamide, poly-ester and polyurethane fibers.
However, it is p
Lorenz Juergen
Wilka Ewald
Cain Edward J.
Dorus Klebetechnik GmbH & Co. KG
Harper Stephen D.
Ortiz Daniel S.
Wyrozebski Katarzyna
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