TW201305256A - Composite material - Google Patents

Abstract

The invention relates to a composite material comprising single, short reinforcing fibres with a length of 0.1 - 50 mm and a matrix made of matrix material surrounding said fibres, the matrix material containing a thermoplastic and the reinforcing fibres polyphenylene sulphide.

Description

Composite material

The present invention relates to a fiber reinforced plastic structure (composite), articles made from the fiber reinforced plastic structure embodying the present invention, and the use of such articles.

Such a plastic structure is a material composed of reinforcing fibers embedded in a plastic matrix. These structures are used in a variety of applications in the form of short fiber reinforced elements, long fiber reinforced elements or endless fiber reinforced elements.

The sub-group "glass-fibre-reinforced plastics" comprises a composite material made of plastic (such as polyester resin, epoxy resin or polyamide) and glass fiber. Glass fiber reinforced plastic is a standard industrial material. Such pipes/pipes are standardized by DIN and are commercially available.

In the field of alkaline fluids, glass fiber reinforced plastics are primarily used to contain or transport alkaline liquids. Glass fiber reinforced plastics typically have a thermoplastic material such as polypropylene as a protective chemical coating. This protective chemical coating is placed on all surfaces in contact with the alkaline solution to protect the fiberglass reinforced plastic. Especially when the temperature of the alkaline solution is higher than 40 ° C, this additional protective coating is required, which strengthens the corrosive action of the alkaline solution, thereby causing the surface to be eroded and destroyed.

At temperatures below 40 ° C and low caustic soda concentrations, the thermoplastic protective chemical coating can be omitted and replaced by the plastic matrix itself.

A disadvantage of the glass fiber reinforced plastic known in the prior art is that Damage to the protective chemical coating exposes the glass fibers and is directly exposed to chemical attack by alkaline fluids.

Glass is a highly chemically resistant material, but it is not resistant to alkaline fluids and is severely attacked and destroyed by alkaline fluids. Since the mechanical stability of the composite is achieved by the reinforcing fibers, the destruction of the reinforcing fibers affects the entire composite. The loss of mechanical stability results in material failure because the material is no longer resistant to pressure loads and thermal loads that are prevalent during operation of, for example, industrial equipment.

Prior art glass fiber reinforced plastic pipes/pipes are known, for example, from DE 10 2008 033 577 A1. This specification particularly demonstrates plastic tubing that exhibits improved properties in terms of leak tightness, stiffness, shape stability, and abrasion as compared to prior art. At the same time, the pipe wall is formed by at least one centrifugal layer produced by centrifugation or centrifugal casting and at least one wound layer produced by a winding method. Although these pipes exhibit improved properties, they are extremely expensive to manufacture.

It is known that due to the significant thermal expansion and softening of thermoplastic plastics at elevated temperatures, it is difficult to use pure thermoplastic plastics, such as polypropylene, as materials for, for example, containers/sumps or pipes/pipes suitable for transporting alkaline fluids.

When it comes to alkaline fluids, it is possible to reduce the thermal expansion and ensure mechanical stability by embedding glass fibers in thermoplastics at temperatures up to 95 ° C, which can cause the above problems, ie corrosion and therefore Destroy the material.

For example, in DE 2008 037 417 A1, filaments are produced from different fibers to form a textile composite, one of which may be polyphenylene sulfide fiber. This filament is used to reinforce the elastomeric matrix material such that the product of the manufacturing process is an elastic workpiece, such as a flexible conduit. The disadvantage of this teaching is the flexibility of the product. Therefore, this composite material is not suitable as a material such as a rigid pipe/pipe or container/storage which must exhibit high rigidity and hardness.

In EP 0 967 240 A2, fiber mats which may contain polyphenylene sulfide are used to strengthen the thermoplastic matrix material. A workpiece manufactured using this invention must be manufactured by compression molding. In this process, the fiber mat is placed in the mold prior to introduction of the thermoplastic, and the thermoplastic is introduced in the second step. This procedure has the disadvantage that it is not possible to mix the thermoplastic plastic with the fiber mat before extrusion; and in addition, the mat must first be produced before the material can be produced, which is time consuming.

Accordingly, it is an object of the present invention to provide an alternative composite wherein the matrix material and the fibrous material are resistant to alkaline fluids at temperatures above 60 ° C to 100 ° C, thereby reducing the likelihood of failure in the manner described above. . The present invention also focuses on the object of providing the use of related articles and composite materials.

This object is achieved by a composite material comprising a single reinforcing fiber having a length of from 0.1 mm to 50 mm and a matrix made of a matrix material surrounding the fibers, the matrix material comprising a thermoplastic plastic and a reinforced fiber polyphenylene sulfide.

Surprisingly, it has been found that materials containing short, single polyethylene sulphide fibers randomly distributed in the matrix material exhibit properties similar to those described in EP 0 967 240 A2, EP 0 967 240 The material described in A2 contains fiber mats made in a complex process and provides a distribution of fibers along the mat. Therefore, since it is not necessary to produce a mat, it is easier to manufacture the material.

In the manufacturing process, the matrix and fibers of the composite are formed into their corresponding forms by extrusion or injection molding, wherein the reinforcing fibers are first mixed with the matrix material, followed by further processing. The thermoplastic matrix material has a processing temperature of about 210 ° C and the reinforcing fibers have a softening point of about 260 ° C. Since the treatment temperature is significantly lower than the latter value, it is ensured that the properties of the reinforcing fibers remain unchanged.

The composite preferably comprises reinforcing fibers having a length of from 10 mm to 25 mm.

In an advantageous embodiment of the invention, the composite additionally comprises an additive which affects the properties of the composite. Such additives are selected from the group of "stabilizers, binders and slip agents" and are known to those skilled in the art.

The composite preferably comprises from 0.05% to 5% by weight of an additive. These additives may be included in the matrix material and/or contained in the fiber material. According to the invention, the matrix material comprises from 95% to 100% by weight of thermoplastic plastic and from 0% to 5% by weight of additives. The fibrous material preferably comprises from 95% to 100% by weight of polyphenylene sulfide and from 0% to 5% by weight of additives.

According to the present invention, the matrix material is selected from the group consisting of polyvinyl chloride, polyphenylene sulfide, polyfluorene, polyethylene, polyamine, polyoxymethylene, and polymethylpentene, wherein the polyphenylene sulfide reinforcing fiber The thermoplastic plastic polyvinyl chloride, polyphenylene sulfide and polyfluorene are particularly suitable for use at temperatures up to 95 ° C, even in the presence of alkaline fluids. In contrast, thermoplastic polyethylene, polyamide, polyoxymethylene and polymethylpentene with polyphenylene sulfide reinforced fibers are suitable. Use at temperatures up to 60 ° C.

Advantageously, the composite of the present invention is resistant to alkaline fluids having a concentration greater than 20%, especially if the alkaline fluid is greater than 20% NaOH. Of course, composites also show resistance to other chemicals.

The composite of the present invention is resistant to alkaline fluids (such as NaOH) and other corrosive fluids at temperatures above 60 ° C to 100 ° C, depending on the thermoplastic matrix material used.

The invention also encompasses articles containing and/or transporting an alkaline liquid, the articles comprising the composite of the invention. Advantageously, such items are pipes/pipes or containers/storage tanks.

These pipes/pipes and containers are fabricated from composite materials using processes known to those skilled in the art. The known process details are as follows: Extrusion process: First, the plastic or extrudate is melted and homogenized by means of heating and internal friction in an extruder (also known as a screw press). The pressure required to pass through the mold is also accumulated in the extruder. In most cases, the plastic leaving the mold solidifies in a water-cooled calibration unit. When a vacuum is applied, the profile is pressed against the wall of the calibrator, thereby completing the forming process. This process step is often followed by a cooling step in the form of a cooling water bath. The cross section of the resulting geometry corresponds to the mold or sizing used.

Injection Molding Process: The thermoplastic injection molding process is the basis for all other injection molding processes and is also the most common plastic processing method.

Today's conventional screw plunger injection molding machines mainly feed the plastic in the form of pellets into the screw passage from the feed funnel, and shear the plastic in the screw passage. The frictional heat generated is combined with the heat supplied by the heating cylinder to ensure a relative average A melt of matter. This melt collects at the tip of the tip of the shrink screw. In the so-called injection phase, the rear part of the screw is subjected to liquid or mechanical pressure, thereby forcing the melt to pass through the nozzle against the injection mold, hot runner system at high pressure (mainly between 500 and 2000 bar) (if present ) (usually used in modern standard molds) and the main runner is pressed into the molding cavity of the temperature-controlled injection mold. The reduced pressure acts as a holding pressure on the melt until the gate freezes (solidifies). This compensates for any material shrinkage during cooling and is used to achieve dimensional accuracy and to achieve the desired surface quality. Thereafter, the screw starts to rotate. When a shot mass is prepared in this manner for subsequent molding, the shaped body in the mold can be further cooled until the liquid core solidifies. The mold is opened and the finished molded body is shot.

The composite of the present invention is primarily used as a material for pipes, pipes and/or vessels/storage tanks wherein the pipes, pipes and/or vessels/storage tanks are in contact with alkaline fluids. These lines, pipes and vessels/storage tanks are also used for alkaline fluids at elevated temperatures above 60 °C.

In a preferred application, the composite material is used in an apparatus for electrolytic processes for producing and/or adding alkaline fluids. Possible uses are mainly the inlet and outlet of the electrolysis unit and the reaction chamber.

Other possibilities for the use of the composite of the present invention are listed below. Such uses include, for example, equipment for the refining metallurgical process for the addition and/or use of alkaline fluids, which process is preferably to refine aluminum from bauxite. Moreover, quite generally, the present invention relates to apparatus for processes for adding and/or using alkaline fluids as is known in the art. Possible uses are mainly the inlet and outlet of the electrolysis unit and the reaction chamber.

Advantages produced by the present invention:

- composite material with good alkali resistance

- A composite that is resistant to high temperatures even in the presence of alkaline fluids.

Claims (18)

A composite material comprising a single short reinforcing fiber having a length of from 0.1 mm to 50 mm and a matrix made of a matrix material surrounding the fibers, the matrix material comprising a thermoplastic plastic and the reinforcing fibers polyphenylene sulfide. The patentable scope of application of the composite material according to item 1, wherein the lengths of these reinforcing fibers to 10 mm for 25 mm. The scope of patented composite item 1 or 2, the system characterized in comprising the composite material selected for the "stabilizers, adhesives and glidants" as the additive group modifier. The patentable scope of application of the composite material of any one of items 1 to item 3, characterized by comprising 0.05 wt% to 5 wt% of the additive composite. The composite of any of the preceding patent application in any range, which is characterized in comprising the matrix material is 95 wt% to 100 wt% of the thermoplastic plastic and 0% to 5% by weight of additives. The composite of any of the preceding patent application in any range, characterized in comprising% to 5% by weight to 95% by weight to 100% by weight of a polyphenylene sulfide and 0 is the weight of the additive fibrous material. The aforementioned patent application in any range of a composite material, wherein the matrix material is selected from the group of: polyvinyl chloride, polyphenylene sulfide, polysulfone, polyethylene, polyamide, polyoxymethylene and poly A Pentene. The composite of any of the preceding patent application in any range, characterized in concentration greater than 20% of an alkaline fluid having a resistance to the composite material. The patentable scope of application of the composite material according to item 8, characterized in having a resistance to more than 20% of NaOH as the composite material. The composite of any of the preceding patent application in any range, wherein the composite material having alkali resistance at higher temperature 60 ℃ deg.] C to 100 of. An article for containing and/or transporting an alkaline liquid, the article comprising a composite material as in claim 1 of the patent application. The scope of the patent as item 11 and receiving / conveying articles or alkaline liquids, wherein the article is a conduit (pipe) or pipe (tube). The scope of the patent as item 11 and receiving / or delivery of items alkaline liquid, wherein the article is a container / tank. A use of a composite material as claimed in claim 1 as a material for pipes, pipes and/or vessels/storage tanks wherein the pipes, pipes and/or vessels/storage tanks are in contact with an alkaline fluid. A use of a composite material as claimed in claim 1 for use as a material for pipes, pipes and/or vessels/storage which is in contact with an alkaline fluid having a temperature above 60 °C. A use of a composite material as claimed in claim 1 for use in a process for the addition and/or use of an alkaline fluid. The use of a composite material as claimed in claim 16 wherein the equipment is an apparatus for the production and/or addition of an alkaline fluid electrolytic process. The use of a composite material as claimed in claim 16 wherein the equipment is a refining metallurgical process for the addition and/or use of an alkaline fluid.