WO1991018968A1

WO1991018968A1 - Synthetic foams

Info

Publication number: WO1991018968A1
Application number: PCT/GB1991/000927
Authority: WO
Inventors: Peter Jeffrey; John Francis Toft
Original assignee: NUCLEUS ENTERPRISE Ltd
Current assignee: NUCLEUS ENTERPRISE Ltd
Priority date: 1990-06-08
Filing date: 1991-06-10
Publication date: 1991-12-12
Anticipated expiration: 1992-12-08
Also published as: GB9012742D0; AU7977191A

Abstract

A synthetic foam is produced which has incorporated detergent. The detergent in substantially dry form is mixed with one of the foam forming reactants prior to the foam forming reaction. Typically for a polyisocyanate foam, the detergent is added to the polyol reactant.

Description

Title: Synthetic Foams

DESCRIPTION

This invention concerns synthetic foams.

Synthetic sponge-like foams, such as of the polyester-polyurethane type, are now being used for cleaning purposes with detergent already incorporated that is released upon wetting of the foam. The detergent is usually injected in liquid form into the foam prior to wrapping. This further step in the production of foams for cleaning purposes obviously occupies time and so increases production costs.

Liquid or solid detergent could be added to the foamable mixture prior to foaming but most detergents hinder the foaming process, to the extent that either the foam detergent often hinders the foaming process, to the extent that either the foam collapses before curing or a closed cell structure is formed, and other detergents can only be tolerated in very small amounts of the order of 5 parts per 100 parts of polyol reactant.

The object of the invention is to incorporate detergents into synthetic foams without substantially hindering the foaming process.

According to the invention there is provided a method of incorporating a detergent in a synthetic foam comprising the step of mixing the detergent in substantially dry form with one of the foam forming reactants prior to the foaming reaction. The invention further provides a foam product made according to the method of the invention.

The detergent may be in granulated, pulverulent, e.g. spray dried powder or flaked form, may be a liquid adsorbed on or absorbed in a solid carrier, may be detergent .manufactured in polyol or may be predispersed in polyol for ease of foam reaction.

One preferred detergent form is as flakes although detergents in other shapes, such as pellets, noodles or powders may be useful. The detergent may be of any suitable type, soap being preferred, although synthetic detergents such as methyl esters of fatty acids, e.g. methyltauride and o-leyl methyl tauride, and surfactants such as non-ionic, anionic, amphoteric and cationic surfactants may be used. Examples of suitable surfactants include alkyl sulphoacetates, for example, lauryl sulphoacetates, alkyl alcohol sulphates, alkyl ether sulphates, sulphosuccinate derivatives alkene sulphonates, alkyl sulphonates, alkyl naphthalene sulphonates . alkyl benzyl sulphonates, alkyl ester phosphates and combinations of any of these. Furthermore, detergents that appear to be substantially incompatible with synthetic foam production due to, for example, inherent stickiness or tendency to cake, such as alkyl ben2ene sulphonates, cocoamido betaine or other anionic, non-ionic or cationic detergents in solid form, may be rendered compatible with synthetic foam production by admixture with a carrier. It is bel^'ieved that a suitable carrier acts by coating the detergent particles to render them free running. The carriers may be organic and/or inorganic. Examples of carriers include calcium sulphate and calcium carbonate or a mixture thereof, such as Franklin fibre, polyphosphates, metasilicates, fumed silica, Neuberg chalk, diato aceous earth, talc polymeric powder, organic absorbants, free flowing dry surfactants and detergents compatible with synthetic foam production such as oleyl methyl tauride and lauryl sulphoacetate. The latter are particularly effective as they also tend to increase detergency reduce release rate of detergent from the foam and reduce toxicity of normally harsh detergents.

For a polyether polyurethane foam such as produced by reaction of a polyol with a polyisocyanate under foaming conditions, the detergent is preferably mixed with the polyol prior to the foaming reaction.

For polyester, polyurethane and polyether foams, it would also be preferable to mix the detergent with the polyol reaction component.

The amount of detergent incorporated in the foam may depend on the end use of the foam as well as the ease with which the detergent combines with the foam ingredients. Preferably at least one part, especially at least 5 parts, of detergent up to say 20 parts even up to 30 parts or possibly more parts of detergent may be included per 100 parts of polyol. For a powder detergent 10 parts per 100 parts of polyol may be acceptable but for a flake detergent higher amounts say 20 parts per 100 parts of polyol and higher may be possible.

It is important that the detergent be substantially evenly distributed throughout the rising foam, as uneven distribution may result in non- reproducible results which are not commercially viable.

It has further been found that detergent products that melt, soften or become sticky during the exothermic foaming reaction tend to inhibit foam formation. It is preferable, therefore, to avoid using such products.

As detergent, surfactants or soaps which are sparingly soluble in water are preferred since relatively soluble detergents that are suitable for the foaming process may dissolve too quickly in contact with water and hence be less effective in cleaning. Relatively soluble detergents may nevertheless be useful if a substance to inhibit detergent release is included. Suitable substances for inhibiting detergent release may include, for example, starch derivatives cellulose derivatives and absorbent polymers, such as Salsorb (sold by Allied. Colloids) and Sanwet (Hoechst) .

To use liquid detergents in the invention, it may be possible to adsorb them onto solid carriers such as activated silica or silica gel or absorb _..them into absorbent material such as absorbent polymeric material. Liquid detergents may also be used in low concentrations as additives to achieve suitable surfactant formulations.

In general, preferred detergents suitable for use in the present invention may be described in the following general terms. Detergents having an aliphatic content and possibly no aromatic content may be most suitable. Anionic detergents may be preferred. Suitable detergents will preferably have low solubility in water. Detergents that are skin-compatible will be preferred. The preferred detergents will be dispersable in the polyol component of the foam and preferably inert to the polyol. Particularly preferred detergents for use in. the invention are ύnsaturated C |_b fatty acid esters or Cι_b fatty acid sulphoalkyl acid esters.

The foam products of the invention will release the detergent upon wetting. Particularly but not exclusively, when using soap type detergents, however, it may be advantageous to further incorporate surfactant to prevent or at least limit formation of scum, defoaming and skin irritation and to enhance cleaning power. Any suitable type of surfactant may be used for example amphoteric surfactants and methyl esters of fatty acids, such as methyl tauride, or cationic products such as cetrimide, benzalkonium chloride or chlorhexidine derivatives, which may have the advantage or providing sterilising and/or disinfecting properties.

Preferred foams produced in the present invention are formed on a continuous process and preferably are of a light density of the order of 18 to 25 Kg/m³. The detergent containing foams of the invention may be put to a variety of uses. The foams may be used for household cleaning purposes for which the incorporation in the foam of one or more builder substances to enhance the detergent action may be desirable. It may be advantageous to provide the foam with an abrasive surface such as of abrasive powder coated or flaked onto the foam using adhesive to bind the powder to the foam. Silica and aluminium derivatives are suitable abrasive materials which may or may not be incorporated into an impregnation coated polyurethane prepolymer. Alternatively, a layer of non- woven fibrous mat such as of polypropylene may be adhered to one or more sides of a foam block.

The above-mentioned abrasive products may also be suitable for use by decorators such as for rubbing down paintwork and cleaning walls. The detergent present in the foam acts as a lubricant in these circumstances as well as providing high performance cleaning power.

Foam products of the invention may also be used for personal hygiene, especially for use wit babies. For such products, customary ingredients of personal hygiene products may be incorporated, such as super fatting agents and perfumes.

Another household use of the foam products of the invention may be as carriers for detergents for use in washing machines. Thus, a foam product of the invention preferably also containing customary ingredients for detergents for washing machines, such as builders, fluorescent agents etc. may be added directly to the washing machine with the clothing etc to be washed rather than using customary liquid or powder detergents currently flushed into the washing machine from a separate chamber. It is envisaged that such a product will enhance the washing process and by the addition of cationic sofening agents also condition fabrics. By the inclusion of a suitable sterilant and/or disinfectant (preferably cationic) then both a hospital/general antiseptic or a household/general disinfectant may be produced.

Yet another use for products of the invention will be for washing motor vehicles and mechanical equipment generally, for which a compatible wax may be incorporated in the foams of the invention.

Because the foam products of the invention can be provided in relatively small sizes, e.g. by compression thereof, such as in rolled up form, they are suitable for medical use, especially on a one-off basis, for example, for bed bathing incorporating a safe surfactant, sterilant cleansers, preferably by including a suitable sterilant substance such as cetramide or chlorhexidine, and other medical disposable uses, as well as for household, industrial and commercial uses. For these purposes, the foam products of the invention may be wrapped under sterile conditions, the wrapping to be removed immediately prior to use.

It has been surprisingly found that by choosing certain surfactants a hydrophilic foam can be produced according to the invention.

Industrial uses for products of the invention are also envisaged for example for both general and sterilant cleansing purposes. A further development of the invention may be to treat foam products of the invention with hot molten soap or surfactant either onto the foam surface or into the foam say by injection. Treatment of the foam surface may be by any suitable means, such as by coating or printing transfer roller, either uniformly or non- uniformly. After cooling the soap/surfactant hardens to give similar properties to the foam product as a soap or synthetic detergent bar.

This invention will now be further described with reference to the following Examples. EXAMPLE 1 (Comparative)

A polyurethane.foam was prepared in the following manner. 3.30 parts of water were dispersed in 100.00 parts of Polyol 3500. 0.27 Parts of blow catalyst, 0.80 parts of foam stabiliser and 0.25 parts of gel catalyst were then added to the water/polyol dispersion. Finally 45.5 parts of toluene diisocyanate were added with good agitation.

The resultant polyurethane foam was sponge-like.

EXAMPLE 2 Example 1 was repeated except that 10.00 parts of a detergent (ARKOPON T) were added to the Polyol 3500 prior to mixing with the toluene diisocyanate. The detergent was not visible in the resultant sponge-like foam but was released on wetting with water. EXAMPLE 3

Again Example l was repeated except that 5.00 parts of a detergent (Lathanol LAL) were added to the polyol 3500 prior to mixing with the toluene diisocyanate. The detergent was released when the foam was wetted with water.

Claims

1. A method of producing a synthetic foam incorporating a detergent comprising the step of mixing the detergent in substantially dry form with one of the foam forming reactants prior to the foaming reaction.

2. A method as claimed in claim 1, wherein the detergent is sparingly soluble in water.

3. A method as claimed in claim 1 or 2, wherein the detergent is granulated or pulverulent forms.^'

4. A method as claimed in claim 2 or 3, wherein in the detergent is a spray dried powder or in flaked form.

5. A method as claimed in anyone of claims 1 to 4, wherein the detergent is mixed with a solid carrier.

6. A method as claimed in claim l, wherein the detergent is in liquid form but on a solid carrier.

7. A method as claimed in any one of claims 1 to 6, wherein the detergent is a soap.

8. A method as claimed in any one of claims 1 to 6, wherein the detergent is selected from methyl esters of fatty acids.

9. A method as claimed in claim 8, wherein the detergent is selected from methyl tauride and^' oleyl methyl tauride.

10. A method as claimed in any one of claims 1 to 6, wherein the detergent is a surfactant selected from non-ionic, anionic, amphoteric and cationic surfactants.

11. A method as claimed in claim 10, wherein the detergent is selected from alkyl sulphoacetates, alkyl alcohol sulphates, alkyl ether sulphates, sulphosuccinate derivates, alkene sulphonates, alkyl sulphonates, alkyl naphthalene sulphonates, alkyl benzene sulphonates, alkyl ester phosphates and combinations of any of these.

12. A method as claimed in claim 11, wherein the detergent is lauryl sulphoacetate.

13. A method as claimed in claim 11, wherein the detergent is mixed with a carrier selected from calcium sulphate, calcium carbonate and mixtures thereof, polyphosphates, metasilicates, fumed silica, Neuberg chalk, diatomaceous earth, talc, polymeric powder, organic absorbants, free flowing dry surfactants and detergents compatible with synthetic foam production.

14. A method as claimed in claim 13, wherein the carrier is Franklin fibre.

15. A method as claimed in claim 13, wherein the carrier is selected from oleyl methyl tauride and lauryl sulphoacetate.

16. A method as claimed in any one of claims 1 to 15, wherein one of the foam forming reactants is a polyol and the detergent is mixed with the polyol.

17. A method as claimed in claim 16, wherein at least 5 parts by weight of detergent are incorporated per 100 parts by weight of polyol.

18. A method as claimed in claim 16 or 17, wherein upto 30 parts by weight of detergent are incorporated per 100 parts by weight of polyol.

19. A method as claimed in claim 16, 17 or 18, wherein upto 20 parts by weight of detergent are incorporated per 100 parts by weight of polyol.

20. A synthetic foam produced by a method.as claimed in any one of claims 1 to 19.

21. A foam product as claimed in claim 20 further comprising a surfactant to at least limit formation of scum, defoaming and skin irritation and to enhance cleaning power.

22. A foam product as claimed in claim 21, wherein the further surfactant is selected from amphoteric surfactants, methyl esters of fatty acids and cationic surfactants.

23. A foam product as claimed in claim 22, wherein the further surfactant is methyl tauride.

24. A foam product as claimed in claim 22, wherein the further surfactant is selected from cetrimide, ben2alkonium chloride and chlorhexidine derivatives.

25. A foam product as claimed in any one of claims 20 to 24 formed by a continuous process.

26. A foam product as claimed in any one of claims 20 to 25 having a density of the order of 18 to 25 kg/m³.

27. A method of making a synthetic foam substantially as hereinbefore described with reference to Example 2 or Example 3.

28. A foam product substantially as hereinbefore described with reference to Example 2 or Example 3.