NL1030771C1 - Carbon dioxide absorbing material, comprises plastically deformable polymer matrix material containing carbon dioxide absorbing substance, preferably alkali metal hydroxide - Google Patents

Abstract

The material comprises a plastically deformable polymer material compounded with a carbon dioxide absorbing substance. A carbon dioxide absorbing material comprises a plastically deformable polymer material compounded with a carbon dioxide absorbing substance. Independent claims are also included for (a) a method for preparing a molded article from this material by injection-molding,(b) a molded article (10) prepared by this method, (c) the use of alkali metal hydroxides as carbon dioxide absorbing substances in plastically deformable polymer materials, (d) the use of calcium hydroxide as a carbon dioxide absorbing substance in plastically deformable polymer materials and (e) the use of polyamide 12 (PA12) as a matrix material for a carbon dioxide absorbing substance.

Description

% - »

Title: Method and device for capturing CO2

The invention relates to the capture of CO2 from the atmosphere.

It is well known that the atmosphere contains low concentrations of CO2. CO2 is a gas that is harmless to people at low concentrations, but at higher concentrations CO2 can be harmful to health, if only because an increase in CO2 concentration is usually accompanied by a reduction in oxygen levels. 10 concentration.

There is therefore, in general, a need for methods for capturing CO2.

This need arises, for example, in areas where people stay for long periods in small confined spaces, for example in submarines or in the field of diving. People consume oxygen and produce carbon dioxide, so that in such confined spaces the CO2 concentration increases as a function of time. It is therefore known to use a so-called CO2 trap in such enclosed spaces, that is to say a substance that, upon contact with the atmosphere, absorbs and binds CO2 from the atmosphere, so that the CO2 content in the atmosphere drops .

This need also arises, for example, in the field of anesthesia, in which narcotics are administered to a patient with breathing apparatus, and in which the exhaled gases contain both CO2 and residues of unused anesthetic gas. If the CO2 is removed, the unused anesthetic gas can be reused.

This need also arises, for example, in the field of storage of products that are sensitive to CO2. Products that are sensitive to CO2, for example some fruits, deteriorate in quality when exposed to the "normal" atmosphere when stored. It is therefore also known to use a CO2 trap in storage rooms for such products.

But there are also areas where CO2 is processed in pressure containers, for example as propellant gas for soft drinks or beer in taps. For connection to such a tapping installation, a beverage container is provided with such a pressure container, which is provided with a closable valve, which can be opened after filling the beverage container. The operation thereby based on the fact that there is a pressure difference with respect to a closed reference chamber. In the unlikely event of a leak, CO 2 could end up in that closed reference chamber, as a result of which the pressure in that chamber rises and the correct operation of the beverage container is no longer guaranteed. To avoid this situation, it is known to provide a CO2 trap in that closed reference room in order to keep that closed reference room CC-free.

The examples given above are not intended as a limiting list.

It is known to use a CO2-absorbing substance as a CO2 trap. A well-known and widely used substance in this connection is known as "sodalime", and contains a mixture of alkaline earth metal hydroxides, mainly calcium hydroxide, sodium hydroxide, potassium hydroxide, to which a binder has been added, and which is added in the in the form of a granulate.

When used in storage rooms for fruit and the like, it is in principle possible to place the granulate in large open bins. When used in equipment such as breathing apparatus or pressure containers (for example for tapping installations) it is not possible and / or not allowed to work with open containers. In such applications, an amount of the CO2-absorbing substance is placed in a container, which will hereinafter be referred to as the "capsule", the shape of which may depend on the intended application.

The use of a capsule entails a number of problems. The capsule must first be manufactured to be filled. The capsule consists of two parts, typically 3 a "container" and a "lid". The bin must be filled with a predetermined amount of CO2-absorbing substance, the lid must be placed, and the lid must be attached to the bin. All these operations require relatively complicated and expensive equipment.

Furthermore, the capsule must on the one hand be permeable to CO2, so that when the capsule is brought into contact with a gas atmosphere, CO2 from that atmosphere can reach the interior of the capsule, but on the other hand the capsule 10 must be impermeable to dust. particles, so that dust particles that will inevitably arise in the capsule as a result of friction or impact of grains against each other are prevented from leaving the capsule. It is difficult to meet these two requirements with a high degree of reliability.

It is an object of the present invention to provide an alternative solution to the aforementioned problems.

The present invention proposes to incorporate a CO2-absorbing substance in a plastic base material (carrier or matrix material) suitable for thermoplastic deformation. The resulting composite product, which will hereinafter be referred to as the "composition", then exhibits both properties, that is, of CO2-absorbing capacity and formability, so that it is possible to make moldings by means of an injection molding process which Have CO2 absorbing capacity. Such moldings need not be included in a capsule or the like, so that production and handling costs can be saved.

The moldings can have an external shape similar to that of a conventional capsule, so that such a mold can serve to directly replace the capsule without the need for adaptations to the rest of the construction of a device in question.

However, it is also possible to manufacture other parts of an apparatus as a CO2-absorbing molding. By way of example, one or more walls of the reference chamber discussed above could be made as a CC> 2-absorbent molding.

Calcium hydroxide is preferably used as the CC> 2 -absorbent. The most important criteria for the active substance to be used are the CO2-absorbing capacity on the one hand, and the capacity to be incorporated in a plastic on the other. Alkali metal hydroxides such as, for example, sodium hydroxide and potassium hydroxide are also suitable, for example. Instead of a hydroxide, it is also possible to use the relevant oxide, which will also capture water vapor as an additional effect, which can be particularly favorable for certain applications.

Polyamide-12 is preferably used as the basic plastic material. The most important criteria for the plastic to be used are the formability, the capacity to absorb the CO2-absorbing substance, and the permeability to CO2. For example, other suitable plastics are: polyethylene, in particular low-density polyethylene; polycarbonate; polypropylene; Polyamide, in particular polyamide-11.

These and other aspects, features and advantages of the present invention will be further elucidated by the following description with reference to the drawings, in which like reference numerals indicate like or similar parts, and in which: Figures 1-3 show a molding according to the present invention to illustrate.

In one experiment, a CC> 2-absorbing thermoplastic polymer composition was prepared by mixing calcium hydroxide with polyamide-12 in a compounding extruder, in a weight ratio of 60% calcium hydroxide and 40% polyamide-12. The polyamide-12 was provided in granular form 35, and the calcium hydroxide was mixed through the granular polyamide-12 stock. The mixture was introduced into the extruder and softened by heating in an otherwise conventional manner. Alternatively, it is possible to plasticize the polyamide-12 in the extruder and add the calcium hydroxide to the soft plastic.

In the extruder, the mixture of plastic and calcium hydroxide was kneaded firmly into an almost homogeneous composition, which was extruded into long strands of the order of 3 mm thickness, which strands were cut into cylindrical granules with a length of the order of 5 mm. Of course, other dimensions are also possible. The product thus obtained is a granular intermediate product that can be used as a raw material in an injection molding process.

· ··········· ΐη a subsequent step, the granulate thus produced was used as raw material in an (otherwise known and therefore not further explained) injection molding process, in which a molding 10 was produced as illustrated in figures 1- 3. This molding 10 is generally in the form of a flat, circular ring with an outer diameter of approximately 20 mm, an inner diameter of approximately 9 mm, and a thickness of approximately 7 mm. Of course, other dimensions are also possible. Axial grooves are provided along the outer circumference to increase the active area. Similarly, such axial grooves are provided along the inner circumference, but extend from the axial end faces to less than half the axial length, so that a circular inner edge is retained in the waist.

In the embodiments shown, the axial end faces are flat, but they could also be ribbed.

The shape and dimensions of the molding were chosen to be the same as those of a capsule known per se for use in a CC> 2 container, as described above, so that the molding could be used to replace that capsule. Subsequently, it was checked whether the molded part functioned effectively to absorb CO2; this indeed proved to be the case, as was optically observed on the basis of a discoloration of the molded part.

It has thus been shown that it is possible to manufacture a CO2-absorbing plastic, which is suitable for being molded into 6 moldings by means of an injection molding process, which can fulfill a CO2-absorbing function in addition to a structural function.

It will be clear to a person skilled in the art that the invention is not limited to the exemplary embodiments discussed above, but that various variants and modifications are possible within the scope of the invention as defined in the appended claims.

1030771

Claims (15)

1. Plastically deformable polymer compound with CO2-absorbing capacity. 2. Plastically deformable compound, comprising a polymer support material and a CO2-absorbing substance. A compound according to claim 1 or 2, wherein the polymeric carrier material is selected from the group comprising polyethylene, in particular low-density polyethylene; Polycarbonate; polypropylene; polyamide-11; polyamide-12. A compound according to any of claims 1-3, wherein the polymeric carrier material consists at least substantially of polyamide-12. 15 A compound according to any of claims 1-4, wherein the CO2 absorbing substance comprises at least one alkali metal hydroxide. 6. A compound according to any of claims 1-4, wherein the CO2-absorbing substance consists at least substantially of calcium hydroxide. 7. A compound according to any of claims 1-6, consisting essentially of calcium hydroxide and polyamide-12. A compound according to any of the preceding claims in granular form. A compound according to claim 7, containing about 60% by weight of calcium hydroxide and about 40% by weight of polyamide-12. 9. Method for manufacturing a molding by means of an injection molding process, wherein a compound according to any one of the preceding claims is used as raw material. 1030771 Molded article made from a compound according to any of the preceding claims 1-8. A molding according to claim 10, in the form of a flat, circular ring (10). The molding of claim 11, wherein at least one of the surfaces of the ring is provided with grooves. 10 13. The use of an alkali metal hydroxide as a CO2-absorbing substance in a plastically deformable polymer compound. 14. The use of calcium hydroxide as a CO2-absorbing substance in a plastically deformable polymer compound. 15. The use of polyamide-12 as a matrix material for the inclusion of a CC> 2 -absorbent. 20 1030771