GB2052544A - A Water-dispersable Material and Articles Made Therefrom - Google Patents

Abstract

The water-dispersable material is produced by mixing together cellulose powder, glass in powder or fibrous form and water to produce a dough or slurry and causing the dough or slurry to dry. Bleached cellulose powder is preferably employed, and water soluble binders or film formers such as for example cellulose ether may be added to the mixture. A filler can also be incorporated in the mixture. The material is particularly useful for forming disposable, moulded articles such as bed-pans, urine bottles and sputum cups.

Description

SPECIFICATION A Water Dispersable Material and Articles Made Therefrom The present invention is concerned with the manufacture of a new material, which is essentially of a water-dispersable nature, but which is capable of forming into relatively rigid bodies. The invention also comprises the material itself; the method of manufacturing articles from the new material; articles made from the material, and a method of rapid disposal of such articles.

A particularly useful application of the invention is in the manufacture of disposable bedpans, urine bottles, sputum cups and the like for use in hospitals, clinics and similar institutions.

For some years now, in the United Kingdom, these items have been made in papier mâché or reconstituted paper pulp, so that after use by a patient, the article can be placed in a waste disposal machine (with its contents still inside it) and the article reduced to pulp by a combined wetting and mechanical action, so that the article and its contents can be washed directly from the inside of the disposal machine into the drain.

This system has advantages for the nursing staff in that it elimates objectionable emptying and washing of the articles, and it helps to prevent crossinfection, because the articles are only used once. However, there are two notable disadvantages, which aret (i) It is almost impossible to produce a papier mach' or reconstituted paper pulp bed-pan which will support the weight of a heavy patient, and consequently it is necessary to use support frames or containers which themselves have to be cleaned, and which are a source of possible infection, (incidentally, it is not unknown for a support container to be placed in the waste disposal machine with consequent damage to both the container and the machine).It might be possible to produce a paper pulp article having the required regidity, but it would have to be so thick that it would present a severe disposal problem.

(ii) The paper pulp can block the drains. This problem arises particularly where there is an accumulation of pulp in a bend of a drain where it can dry, because the dried pulp produces a "moulded" mass in the drain which is difficult to dislodge.

By use of the invention it is possible to overcome or at least alleviate both these problems. It will be appreciated however that the invention is not restricted in its application to bedpans, urine bottles, sputum cups and the like.

According to this invention a water-dispersable material is produced by mixing together cellulose powder, glass in powder or fibrous form and water to produce a dough or slurry and causing the dough or slurry to dry. Preferably bleached cellulose powder is employed. The material produced by this method has a hardness similar to that of certain of the harder plastics materials, and is capable of forming rigid articles (for instance, if the material is moulded into the shape of a bed-pan having a wall thickness of about 3 millimetres, it is capable of supporting the weight of a patient). Another characteristic of the material is that it is dispersable in water: whilst if merely left in water, the material disperses over a period, the dispersal is considerably accelerated if the article is agitated whilst immersed in water.

The precise chemical action has not yet been identified, but it appears that the bleached cellulose reacts with the glass, causing the latter to change into a flocculated substance. When the material is caused to disperse in water, it breaks down and the only residue is a silica type powder which passes easily through drains and far from causing blockages actually has a cleansing effect.

This silica-like material is presumably produced by the glass, but there is no apparent residue of cellulose powder and indeed the cellulose powder is thought to be soluble to infinity.

Preferably the bleached cellulose powder is that sold under the Trade Marks CEPO S.20 and CEPO S.40. It is preferred to use "glass fibre wool" to provide the glass content of the mix.

Preferably the two basic ingredients are present in the range 25% to 65% (by weight) bleached cellulose powder and 35% and 75% glass fibre or powder.

The water required to form the mixture into a workable dough or slurry is preferably added in the range 1 to 2 parts by weight water to 1 part by weight solids.

Water soluble binders or film formers may also be added to the mix. For example, cellulose ether may be added to the mixture of bleached cellulose powder and glass fibre or powder. The cellulose ether may be present in up to 10% by weight of the solids. One mix which has been found to be suitable is approximately 1 part cellulose ether, 4 parts CEPO S.20 and 8 parts glass fibre wool (all by weight).

Part of all of the cellulose ether may be substituted by a colloid such for example as those sold under the Trade Marks Glascol HH and Glascol HN or by other soluble polymers.

It is to be understood that the proportions of the solid ingredients can be varied within quite wide limits, although such variations will affect the resulting properties of the material. Generally, the strength of the material is derived from the glass present in it, but it may be economical to use large percentages of the glass-though on the other hand, inferior glass which might not be suitable for other products wherein the special properties of glass are required, might be used, and glass fibre and/or glass powder may be produced from otherwise waste glass.Also, a relatively high percentage of bleached cellulose has the effect of decreasing the water immersion time required to disperse the material, but additives with a relatively high viscosity such as cellulose ether prolong the immersion time required for dispersal. (For example, a material comprising 1 part cellulose ether; 4 parts CEPO S.20 and 3 parts glass fibres-all by weight would give a product requiring a relatively long dispersal time.

Dryers and/or plasticisers such as calcium chloride or Glycerol may also be used in the formulation, say in the proportion of up to 10% of solids by dry weight. Other additives required to give characteristics such as colour and smell may also be used if required.

it may also be desirable to add special fillers such as highly bleached timber (especially spruce or eucalyptus), which can be reduced to a more flocculated form by the addition of titanium dioxide (TiO2) for example. Talc, reconstituted paper pulp, papier mach', textile fibres, clay, peat or carbon powder such as charcoal, could be used in order to modify the characteristics of the material, or for economy. Clearly some of these will not be soluble in water (though charcoal for example, has good dispersal characteristics) and may detract from the water-dispersal characteristics, but on the other hand, these fillers may be otherwise useful.

According to a preferred feature of the invention, the mixing action comprises a severe mechanical action. It may, for example, be carried out in a mechanical mixing machine of the type used for high speed dough mixing in the bread making industry, this type of mixer being adapted to produce considerable shearing of the dough or slurry during the mixing process.

As mentioned above, paper pulp may be used as a filler, and if so, the mixing process is preferably so severe and of such duration, there there is substantially complete separation of the paper fibres from each other (i.e. they are no longer in mesh with each other). Thus one ontains a very even distribution of the paper fibres in the colloidal silica cellulose dough.

If waste paper is used to provide the paper pulp, then the paper is first macerated wet in a comminuting chamber, and then allowed to dry to remove ink and other contaminants.

According to a preferred feature of the invention an article is manufactured by moulding, extruding or otherwise forming the material to produce the required article shape. As has been previously mentioned, it is possible to mould the material into bed-pans, urine bottoles, sputum cups and like hospital disposable items in this manner.

Whilst reference has been made to "moulding" it is to be understood that it is intended to mean pouring or forcing the material into a shaped mould, and not to the mere disposition of the material on a felt or web as in a paper-making process. Hence there is no effluent produced by the method of manufacture.

If part of the article made from the new material is likely to be exposed to liquids in use (as in the case of the hospital disposables for example) it may be necessary to provide a moisture-resistant coat on the exposed surface(s) and/or to produce the article from composite layers of material, the layer which is exposed to moisture having a longer disperal period than the remainder of the article.

Various examples in accordance with the invention will now be specifically described.

Example I A material is produced having the following formulation, in parts by weight.

1 part cellulose ether sold under the Trade Mark Celacol HPM 5000.

4 parts bleached cellulose powder sold under the Trade Mark CEPO S.20.

8 parts glass fibre wool.

28 parts water.

The dry products (bleached cellulose powder and glass fibre) are mixed together in a conventional mixing machine, and the cellulose ether is added. Then the water is added and mixing continued until a slurry is produced. During the mixing process, the chemical reaction and the physical agitation cause the glass fibres to break down and the resulting slurry is not fibrous, though some short fibres may be present in it.

The slurry is then poured into a mould designed to produce a self-supporting bed-pan, and the material is allowed to partially set in the mould before it is withdrawn from the mould.

After removal from the mould, the article is allowed to dry so that it becomes a rigid bed-pan having an appearance and "handle" similar to that of an article made in hard grade of plastics.

(In some instances the article may be dried in the mould). However, the bed-pan produced by this method is very rapidly dispersable in water, because of its constitution, and hence would not be suitable for use by a patient. The inside exposed surface of the bed-pan is therefore given a non-toxic water-repellant coating which will enable it to withstand the water content of urine during use.

When the bed-pan has been used, it is placed in the comminuting chamber of a hospital type waste disposal machine, and when the machine is operated, the bed-pan is subjected to spraying and immersion in water and to a rapid mechanical agitation. As a result, the bed-pan breaks down and is rapidly dispersed in the water in the form of very fine silica particles, which pass easily out through the drain to which the machine is connected. It is known that most if not all the material forming the bed pan is dissolved by the water penetrating the structure of the article.

In the above method, reference has been made to gravity moulding, but it is to be understood that other moulding techniques could be employed, for example, vacuum moulding or spreading on a former (in the same way that glass reinforced plastics material is sometimes spread on a former). Further, the drying of the article may be ordinary atmospheric drying, or it may be carried out in an elevated temperature, in order to accelerate the drying, or the article may be dried in a vacuum chamber, in which the moisture content of the article is caused to evolve as steam, due to the reduction in pressure. The vacuum cooling technique is particularly advantageous, in that it can be carried out very rapidly, so long as it is not so rapid that the article suffers physical disintegration.

Example II A material is produced having the following formulation, in parts by weight: 32 parts glass fibre.

4 parts CEPO S.20 powder.

1 part Celacol M 450.

20 parts water.

The manufacturing technique is identical with that described in Example I, but because of the difference in the constitution, a very tough bedpan is produced, which would take approximately half an hour to disperse if left in water. Even when subjected to mechanical agitation in a hospital waste disposal machine, a bed-pan constructed in accordance with this example would take a considerable time to break down. On the other hand, the great strength of the bed-pan made by this formulation could be of value in certain circumstances.

Example III A material is produced having the following formulation, in parts by weight: 1 part Celacol M 450.

8 parts CEPO S.20 powder.

4 parts talc.

3 parts glass fibre.

1 6 parts water.

Again, the manufacturing technique is exactly the same as that described in Example I above, and this is a medium formulation, which will give quite a strong bed-pan, and at the same time one which can be dispersed in a hospital waste disposal machine in a relatively short time.

Example IV A material is produced having the following formulation, in parts by weight: 1 part paper pulp.

1 part glass fibre.

T part titanium dioxide.

1 + parts talc.

- part M 450 (cellulose ether).

+ part CEPO S.20 (bieached cellulose).

7 parts water.

The above ingredients are first mixed together dry in a high speed mixer similar to the mixers used for dough mixing in the bread making process, in order to obtain a finely flocculated mass, the glass fibres having been reduced in bulk by the chemical reaction of the bleached cellulose and titanium dioxide, and after a few seconds of the severe dry mixing, the whole is ready for receive the water. Then the water is added and approximately one minute of further high speed mixing produces a dough ready for use, although it is preferable to leave the dough approximately twenty minutes before moulding it to give the added precaution of ensuring complete wetting out of the cellulose ether content. The dough is then moulded and dried producing a very tough, shaped bed-pan, which apart from being stronger than a bed-pan made from reconstituted paper pulp, is completely dispersable in water.It should be mentioned that an alternative method of mixing the ingredients is to add the given water content to the paper pulp first and then add this to the other dry, previously mixed, components.

Example A material is produced having the following formulation, in parts by weight 3 2 parts glass fibre.

4 parts CEPO S.20.

1 part talc.

1 part titanium dioxide.

1 part M 450 (cellulose ether).

3 parts paper pulp.

40 parts water.

The above ingredients are mixed in similar manner to that described in Example IV, and a good bed-pan is produced, which, although not as strong as the one made from the ingredients mentioned in Example IV, is nevertheless rapid in dispersal in water, and the strength is adequate for some purposes.

Example VI A material is produced having the following formulation, in parts by weight: 3 2 parts glass fibre.

4 parts CEPO S.20.

1 parttalc.

2 part titanium dioxide.

1 part M 450 (cellulose ether).

20 parts water.

A similar method is used as that described in Example IV, but the water is added to the already mixed dry ingredients, and in this example, it will be noted that waste paper pulp is not employed.

Example VIII A material is produced having the following formulation, in parts by weight 3+ parts glass fibre.

4 parts CEPO S.20.

1 part titanium dioxide.

1 part M 450 (cellulose ether).

26 parts water.

A similar method is used as that described in Example IV. This formulation is akin to that of Example VI, and is of fine dissolution. A strong moulded and dried object is obtained by this formulation, without the use of paper waste. In fact, it is considered that this formula produces an article of optimum dispersal and strength qualities.

Claims (22)

Claims

1. A method of producing a water-dispersable material comprising mixing together cellulose powder, glass in powder or fibrous form and water to produce a dough or slurry and causing the dough of slurry to dry.

2. A method of producing a water-dispersable material as claimed in Claim 1, in which bleached cellulose powder is employed.

3. A method of producing a water-dispersable material as claimed in Claim 2, in which the bleached cellulose powder is that sold under the Trade Marks CEPO S.20 and CEPO S.40.

4. A method of producing a water-dispersable material as claimed in any one of Claims 1 to 3, in which the glass is "glass fibre wool".

5. A method of producing a water-dispersable material as claimed in any one of Claims 1 to 4, in which bleached cellulose powder is present in the range 25% to 65% (by weight of the totai dry ingredients) and bleached cellulose powder is present in the range 35% to 75% (by weight of the total dry ingredients).

6. A method of producing a water-dispersable material as claimed in any one of Claims 1 to 5, in which the water is added in the range 1 to 2 parts by weight to 1 part by weight solids.

7. A method of producing a water-dispersable material as claimed in any one of Claims 1 to 6, in which a water soluble binder or film former is also added to the mix.

8. A method of producing a water-dispersable material as claimed in Claim 7, in which cellulose ether is added to the mixture of bleached cellulose powder and glass fibre or powder.

9. A method of producing a water-dispersable material as claimed in Claim 8, in which the cellulose ether is present in up to 10% by weight of the solids.

10. A method of producing a water-dispersable material as claimed in Claim 9, in which the mixture comprises approximately 1 part cellulose ether, 4 parts CEPO S.20 and 8 parts glass fibre wool (all by weight).

11. A method of producing a water-dispersable material as claimed in any one of Claims 8 to 10, in which part or all of the cellulose ether is substituted by a colloid such for example as those sold under the Trade Marks Glascol HH and Glascol HN or by other soluble polymers.

12. A method of producing a water-dispersable material as claimed in any one of Claims 1 to 11, in which a drier and/or a plasticiser is added to the mix.

1 3. A method of producing a water-dispersable material as claimed in Claim 12, in which the drier and/or plasticiser is present in up to 10% of the solids by weight.

14. A method of producing a water-dispersable material as claimed in any one of Claims 1 to 13, in which a filler is added to the mix.

1 5. A method of producing a water-dispersable material as claimed in Claim 14, in which the filler comprises one or more of: bleached timber, talc, reconstituted paper pulp, papier much8, textile fibres, clay, peat and carbon powder.

1 6. A method of producing a water-dispersable material as claimed in any one of Claims 1 to 1 5, in which the mixing action comprises a severe mechanical action.

1 7. A method of manufacturing a waterdispersable article from a material produced by the method of any one of Claims 1 to 16, in which the material is moulded (as herein defined), extruded or otherwise formed to a required shape.

18. A method of manufacturing a waterdispersable article as claimed in Claim 17, in which a moisture-resistant coat is formed on the article.

19. A method of breaking down glass into a flocculated mass which is of a dispersable nature in water by mixing together cellulose powder, glass in powder or fibrous form and water to produce a dough or slurry.

20. A method as claimed in Claim 19, in which the cellulose powder used in bleached cellulose powder

21. A method of producing a water-dispersable material substantially as herein described with reference to any one of Examples I to VII.

22. A method of manufacturing a water dispersable article substantially as herein described with reference to any one of Examples I to VII.