GB2091305A - Insulating materials and methods of making same - Google Patents

Abstract

An insulating material which recycles waste paper is produced by pulping the paper and adding to the thus formed pulp a composition including a liquid detergent, sodium carbonate as a fire retardent, and a foaming agent. The material is then allowed to drain whereupon it assumes a pasty consistency which can be used to form moulded blocks or can be applied directly to a surface to be insulated. Alternatively, a part- finished product can be produced by pulping paper, wood pulp or rag, adding to it a liquid detergent, and subsequently allowing the surplus moisture to drain or otherwise be expressed. A fire retardent, which again may be sodium carbonate, a foaming agent, and perhaps also a water soluble adhesive and/or a pigment is then added to the paste and the whole thoroughly mixed or kneaded and either packaged in the moist state or dehydrated and granulated or pulverised. Upon reconstitution by the addition of water the foaming agent expands to form a cellular structure and the amount of water employed for reconstitution can control the consistency of the material in dependence on its intended manner of application.

Description

SPECIFICATION Insulating materials and methods of making same The present invention relates generally to insulating materials and to a method of making insulating materials capable of providing thermal insulation for a wide range of purposes at an economical cost.

The present invention also relates to a composition for use in making insulating materials, and to a method of manufacturing such a composition and of producing an insulating material using such a composition as one of the starting materials.

Insulating materials currently employed for the provision of thermal insulation in buildings include mineral wool, glass fibre mat and vermiculite, which is an expanded granular micaceous asbestos-like material. Although such materials are effective in providing a good degree of insulation when properly used, they are expensive to produce, they use up natural resources and they can constitute a health hazard in that they are composed of very fine rather hard fibres. It is known that the cause of many respiratory troubles is the lodging, in lung tissue, of inhaled fibres of this nature. Indeed, there are considerable restrictions on the use of asbestos and products using asbestos because of this health hazard, and many of the materials conventionally used for thermal insulation purposes have very similar physical and mechanical properties.

The present invention seeks to provide a thermal insulating material suitable for buildings and particularly for domestic use, for example to provide insulation of the roof void in houses, or to provide lagging for water pipes, in which there is no health hazard, and which moreover has the added advantage of recycling what is frequently a waste material.

The present invention also seeks to provide a method for manufacturing such insulating material, a composition for use in the manufacture, a method of making this composition, and a method of employing the composition to provide thermal insulation for buildings.

According to one aspect of the present invention, there is provided a composition for use in forming an insulating material by addition to a saturated fibrous pulp, comprising a surfactant to which has been added a foaming agent. The present invention also comprehends an insulating material comprising a bulk fibrous pulp material expanded by the addition of a liquid composition including a foaming agent.

The bulk fibrous pulp material may be of any suitable nature but it has been found that a pulp made by soaking paper in hot water is particularly suitable. For this purpose any non-glazed paper or cardboard may be used which can be broken down into a pulp state by the addition of an aqueous solution or by water (which may be hot water or steam under pressure). Other pulp materials, such as wood pulp or rag pulp, broken down from their dry constituents by the use of suitable chemicals and/or working (such as beating or tearing) may be used with advantage.

Since the insulating material of the present invention may include constituents susceptible to fire, in particular cellulose fibres of wood pulp or paper, it is preferred to include a fire retardant in the finished product, either by introducing such in suspension or solution in the liquid composition added to the fibre pulp material, or subsequently during the production process, to provide the finished material with a degree of resistance against fire. The fire retardant may be sodium carbonate, which may range from 40% to 65% of the composition and is preferably 50%.

Alternatively the fire retardant may be one of a number of commercially available such materials, for example the products sold under the trade names "Amgard BQ" and "Amgard MPS" by Albright and Wilson Ltd., in which case the manufacturers recommended proportions are between 10% and 20% by weight of the finished (dry) product.

The proportion of foaming agent in the composition may range from 5% to 1 5% and is preferably 10%.

When the foamed fibrous pulp material is allowed to dry it produces a resistant, firm and light material which can be fitted in a roof void in much the same manner as conventional loftinsulation materials, or can be used in a wide range of processes to produce insulation against loss of heat. One such process involves positioning the material in situ whilst it is still moist, so that it will adhere, for example to walls or to the underside of the slates of a roof, whilst it is drying out. For use directly on walls the material may be pigmented either by inclusion of a pigment in the composition added to the pulp, or by the addition of pigment during or after the addition of the composition to the pulp.

In order to improve the take-up by the fibrous pulp material of the foaming agent and the sodium carbonate, and to improve the adhesion of the material when used in the above described way, it is preferred that the liquid composition added to the fibrous pulp material comprises or includes, or further includes, a liquid detergent. It has been found that for this purpose a strong detergent such as those used for breaking up marine oil slicks is eminently suitable. The proportion of detergent in the composition may range from 25% to 50% and is preferably 40%.

The bulk fibrous material may be further reinforced by an additional binding agent to enable it to be used in situations where it will be subjected to a degree of abrasion so that it may need a substantial mechanical resistance and strength. The additional binding agent may be an epoxy resin or any one of a range of materials found to give the finished insulating material an adequate physical strength. Likewise, in use, a suitable waterproof coating may be added after application of the material or a suitable material may be incorporated in the composition to make the finished material impervious to water.

The present invention also comprehends a method of making an insulating material such as that defined above, comprising the steps of saturating a bulk fibrous material with water or with an aqueous solution, agitating the saturated bulk fibrous material to disperse the fibres evenly and form a homogeneous pulp, adding a liquid composition including a foaming agent to the pulp, further agitating the bulk fibrous pulp to disperse the liquid composition evenly therethrough, and allowing the material to expand under the action of the foaming agent whilst allowing excess liquid to drain away before shaping the material in a mould or in situ.

Preferably, as mentioned above, the liquid composition includes sodium carbonate as a dispersion or solution with the foaming agent to provide the finished material with a degree of fire resistance. Preferably, likewise, the surfactant in the said liquid composition is a detergent which improves the adhesion of the material when positioned in situ before dry. Other constituents may include a rodent deterrent, such as aluminium ammonium sulphate, and an algae or fungi inhibitor such as that sold under the trade name of vantoc CL by Durham Chemicals Ltd.

The drainage surface may be formed as a mould with at least one foraminous wall through which the excess liquid can escape whilst the material is drying and hardening. As an additional application, material made as described above may be used for making moulded hollow or solid articles, in particular flower pots or blocks for use in the propagation of seeds or seedlings comprising a block of the dehydrated material having a recess for receiving a seed or seedling.

The bulk fibrous material may be constituted by paper, particularly newsprint, and this may be formed into a pulp by saturating it with hot water or with steam under pressure, accompanied in either case by agitation. After the addition of the liquid composition and further agitation to disperse the foaming agent throughout the pulp, the material may be applied, either directly or after a certain delay to allow excess moisture to escape, to the final working position which may be around a waterpipe, on a wall or in a roof void. Application may be effected by trowel or other tool and the material then allowed to dry in situ.

The present invention further comprehends a composition for use in forming an insulating material by addition to a saturated fibrous pulp, comprising a surfactant to which has been added a foaming agent. Preferably, but not essentially, the addition of the foaming agent is made under conditions where it will form an emulsion with the surfactant. The composition preferably further includes sodium carbonate added to the surfactant prior to the addition of the foaming agent, and again under conditions of high speed agitation such as to form an emulsion with the surfactant.

A method of making the composition according to the invention defined above may comprise the steps of introducing the surfactant into an emulsifying machine, gradually adding the sodium carbonate at room temperature whilst operating the machine at high speed to effect emulsification, and subsequently adding the foaming agent whilst continuing to agitate the composition at high speed. It has been found that one advantageous side effect of the composition of the present invention is that, when added to saturated newsprint it encourages removal of the ink, leaving the pulp almost entirely ink-free after the saturating water has been removed. The composition of the present invention can thus advantageously be used in other processes involving the recycling of newsprint.

The method of manufacturing a thermal insulating material according to the invention may be adapted for industrial or semi-industrial use.

Such a method preferably comprises the steps of saturating a bulk fibrous material with water or with an aqueous solution, agitating the saturated bulk fibrous material to disperse the fibres evenly and adding a liquid surfactant to the dispersion whilst there remains an excess of liquid, subsequently pressing out the surplus liquid or allowing it to drain to form a moist pulp, adding a fire retardant (preferably sodium carbonate) and a foaming agent to the material whilst in a plastic state and thoroughly mixing the constituents in a kneading type mixing apparatus and passing the dough thus formed for further processing. The further processing of the dough formed by this method may include forming the dough into blocks or bricks and packaging in an airtight water impermeable container in which it can remain in its moist state until being reconstituted for further use.It is envisaged that packs of such material could be sold on a DIY basis through retail outlets.

Alternatively, the further processing of the material may include pressing and rolling to express the whole of surplus moisture therein, followed by completel dehydration and breaking down on the material into a powder, flakes or granules. Again, such partly finished product can then be sold as a material for reconstitution either as a trade material or on a DIY basis as before.

One advantage of this lies in the accuracy with which industrial processes can be used to control the proportions of the constituents so that a given weight of material can be added to a selected volume of water to provide, with a degree of certainty, a workable consistency for use in any desired manner. For example, if it were intended to apply the material directly to walls or other surfaces, the amount of water to which the partly finished product would be added should be greater than if a doughy or pasty consistency were required for example for loft insulation. It is also envisaged that at some stage in the process a component will be added to the material which will make the finished insulating material water impermeable without requiring a coating.

One example of a method of producing a thermal insulating material according to the invention will be described below with reference to its production in a domestic situation on an individual batch basis.

A material made in this way is required to have good physical properties of mechanical strength, bending resistance, resistance to crushing as well as being light and stiff to facilitate handling. A material which has these properties can be made by the method described in the following example: One newspaper (preferably a broadsheet size newspaper, although two tabloid size newspapers may alternatively be used) is separated into sheets each of which is lightly crushed into a ball and placed in a ten litre bucket. Five litres of boiling water is then poured into the bucket and the paper allowed to soak for ten minutes to disintegrate. It has been found that it is essential to use hot water for this purpose since it breaks up the newspaper into pulp far more satisfactorily than cold water. It is not entirely clear why this is so, but it is.

thought that hot water dissolves the binders which hold the fibres of the paper normally together. After having soaked for ten minutes the paper is agitated, either with a stirring implement or by hand (the water should have cooled by this time to a temperature low enough to allow contact with the skin). Agitation continues until the paper is completely broken up into a homogeneous pulp, following which a measured quantity of a liquid composition comprising a detergent emulsified with sodium carbonate and a foaming agent is introduced. With five litres of hot water it has been found that fifty millilitres of the composition having the preferred proportion set out above is sufficient. Further agitation of the pulp to disperse the liquid composition through the bulk material is required, and then the pulp can be turned out onto a draining surface to allow the excess liquid to drain away.At this stage the pulp assumes the consistency of a gel and can be formed to any shape required. For example it can be placed into a rectangular mould to make blocks of a given size for subsequent use, or can be applied directly to the required location such as by plastering with a trowel or float, or laying up by hand. The material has a good adhesion to most surfaces, and can even be made to adhere to the undersurface of slates or tiles of a roof void; the addition of an adhesive in the composition or to the saturated pulp further enhances the adhesion.

Form this stage it takes the gel from forty eight hours to seventy two hours to dry out following which, if it has been moulded in a block form, it is ready for use.

Added mechanical resistance can be provided by introducing an epoxy resin to the pulp prior to draining the excess liquid from it, and with this addition the material may be spread out to form thinner elements than would be the case if only the insulating properties were required.

In the example given above the material may be utilised in a thickness of, for example, three to four inches, although any greater thickness may be utilised if adequate raw materials are available.

With the addition of an epoxy resin to make a resistant surface, the material may be made up into elements in the region of one to two inches thick, and such elements may be used as wall tiles, ceiling tiles, or even as flooring tiles since their mechanical strength is quite considerable.

Even without the epoxy resin the physical properties of the material are substantially better than those of conventional thermal insulating materials, both as regards resistance to knocks and dents (for the purpose of wall insulation) and as regards resistance to crushing. This latter feature is a considerable advantage since, when used as a loft insulating material, it will not preclude the conventional use of a loft space to store items of unwanted furniture and the like, and will also readily withstand the imposed load, which frequently occurs, due to dust and flaking material within the roof void. Conventional loft insulating material, particularly mineral wall and fibreglass insulation, is very easily crushed by a superimposed load such as by dust or material flaking from the interior of the loft space, and the insulating effect is seriously deteriorated by such crushing.

In addition, the resistance to moisture of conventional insulating materials leaves much to be desired. Such materials are, in fact, non absorbent but they tend to compact if they become wet, and thereby lose their insulating properties to a large extent. The material of the present invention is absorbent to a certain degree, and can thus accommodate the degree of moisture without loss of physical or insulating properties. Thus, for example, in the event of the loss of a section of slates from a slate roof in a storm, the material of the present invention can absorb a large quantity of water which may enter the roof void as rain without allowing this water to pass through to damage the ceilings providing the roof is recovered before the limit of absorbency of the material is reached.Subsequently, evaporation of the water from the insulating material takes place leaving it in a good condition to continue its function. With conventional materials, however, the above mentioned compaction takes place and replacement is necessary.

The present invention thus provides insulating material which has advantageous properties when compared with conventional insulating materials, which can be made very inexpensively, and which can re-cycle materials which might otherwise go to waste, making a useful product from them and at the same time further economising on subsequent fuel costs. In addition, health hazards involved in the use of conventional short staple hard fibre materials are not present with the material of this invention.

Finally, the material of the present invention can be made up from raw materials such as waste newsprint, as required without incurring any substantial further expense so that extension to the insulation of a loft space can be made from time to time as required, and a layer of substantial thickness can be built up over a period of time if this should be required. Because of the low cost of the insulating material of the present invention substantial thicknesses can be utilised to maximise the insulating effect without suffering from the diminishing returns which conventional materials involve due to their high cost.

Furthermore, because in the normal course of events a householder will continually be acquiring newspapers, these can be periodically used to increase the thickness of the insulating layer thereby improving thermal insulation with the passage of time.

Claims (43)

1. A composition for use in forming an insulating material by addition to a saturated fibrous pulp, comprising a surfactant to which has been added a foaming agents.

2. A composition as claimed in Claim 1 further including sodium carbonate added to the surfactant prior to the addition of the foaming agent.

3. A composition as claimed in Claim 1 or Claim 2 in which the proportion of the surfactant in the composition lies in the range from 25% to 50%.

4. A composition as claimed in any of Claims 1 to 3, in which the surfactant is a detergent.

5. A composition as claimed in any preceding claim, in which the proportion of sodium carbonate in the composition lies in the range from 40% to 65%.

6. A composition as claimed in any preceding Claim, in which the foaming agent in the composition lies in the range from 5% to 15%.

7. A composition as claimed in any of Claims 4, 5 or 6, in which the detergent is lissapol nx.

8. A composition as claimed in any preceding Claim, in which the foaming agent is present in a proportion of 10% by weight.

9. A composition as claimed in any preceding Claim, further including a pigment.

10. A composition as claimed in any preceding Claim, further including a water soluble adhesive.

11. A composition as claimed in any preceding Claim, further including an additional binding agent or one-part of a reactive two-part curing binding agent.

12. A composition as claimed in any preceding Claim further including a component for making the finished insulating material unpalatable to rodents.

13. A composition as claimed in Claim 12, in which the said component is aluminium ammonium phosphate.

14. An insulating material comprising a bulk fibrous pulp material expanded by the addition of a liquid composition including a foaming agent.

1 5. An insulating material as claimed in Claim 14, in which the liquid composition includes sodium carbonate in suspension or solution.

1 6. An insulating material as claimed in Claim 14 or Claim 15, in which the liquid composition comprises or includes, or further includes, a surfactant such as a detergent.

17. An insulating material as claimed in any of Claims 14 to 1 6, in which the bulk fibrous material is further reinforced by an additional binding agent.

18. An insulating material as claimed in Claim 17, in which the additional binding agent is an epoxy resin.

1 9. An insulating material as claimed in any of Claims 14 to 18, in which the fibrous pulp material is paper.

20. An insulating material as claimed in any of Claims 14 to 18, in which the fibrous pulp material is wood pulp.

21. An insulating material as claimed in any of Claims 14 to 20, further including a pigment.

22. An insulating material as claimed in any of Claims 14 to 21, further including a water soluble adhesive.

23. A method of making the composition of Claim 2 or Claim 3, comprising the steps of introducing the surfactant into an emulsifying machine, gradually introducing the sodium carbonate at room temperature whilst stirring at high speed with the emulsifying machine, and finally adding the foaming agent whilst continuing to stir at high speed with the emulsifying machine.

24. A method of making an insulating material, comprising the steps of saturating bulk fibrous material with water or with an aqueous solution, agitating the saturated bulk fibrous material to disperse the fibres evenly throughout the mass, adding a liquid composition including a foaming agent to the saturated pulp, further agitating the bulk fibrous material to disperse the liquid composition evenly therethrough, and allowing the material to expand under the action of the foaming agent whilst allowing excess liquid to drain from it before further processing the material.

25. A method as claimed in Claim 24 in which the said liquid composition is that claimed in any of Claims 1 to 10.

26. A method as claimed in Claim 24 or Claim 25, in which the material is supported for drainage by a drainage surface which is formed as a mould with at least one foraminous wall.

27. A method as claimed in Claim 26, in which the said mould is a cylinder with a plurality of holes in the wall thereof at least in the vicinity of one end.

28. A method as claimed in Claim 25, 26 or 27, including the step of applying a pressure to the material during its drying and expansion to limit the expansion thereof.

29. A method as claimed in any of Claims 24, 25 or 26, in which the bulk fibrous material is saturated and broken down by steam under pressure applied as a preliminary step or contemporaneously with saturation with water or an aqueous solution.

30. A method as claimed in any of Claims 24, 25 or 29, in which the material after drainage is applied to a surface to be insulated whilst still in its damp state, and allowed to dry in situ.

31. A method as claimed in any of Claims 24, 25, 27, 28 or 29, in which the said further processing includes mechanical agitation during further drying to form the dehydrated material into flakes, powder or granules ready for use in that form.

32. A method of making a product for use in insulating a wall or other surface, comprising the steps of: saturating a bulk fibrous material with water or with an aqueous solution, agitating the saturated bulk fibrous material to disperse the fibres evenly and adding a surfactant to the dispersion whilst there remains an excess of liquid, subsequently pressing out the surplus liquid or allowing it to drain to form a moist pulp, adding a fire retardant (preferably sodium carbonate) and a foaming agent to the material whilst in a plastic state and thoroughly mixing the constituents in a kneading type mixing apparatus and passing the dough thus formed for further processing.

33. A method as claimed in Claim 32, further including the step of introducing a water soluble adhesive such as wood glue or wallpaper adhesive to the drained pulp with the fire retardant and foaming agent.

34. A method as claimed in Claim 32 or Claim 33, in which the said further processing comprises the formation of the moist dough into moulded blocks or bricks, and packaging these in water and air impermeable packaging material whereby to resist or prevent dehydration.

35. A method as claimed in Claim 32 or Claim 33, in which the further processing comprises dehydrating the dough and subsequently breaking it down into a powder, granules, or flakes.

36. A method as claimed in Claim 29 including the step of pressing and/or rolling the moist dough prior to or as part of the dehydration thereof, whereby to express moisture therefrom and to extend the surface area to facilitate drying,

37. A method of producing an insulating material comprising the steps of forming a dried product by the method of any of Claims 26 to 30, and subsequently reconstituting the material by the addition of a predetermined quantity of water.

38. A product for use in the preparation of an insulating material, in the form of a powder, flakes or granules produced by a method as claimed in Claim 35.

39. A product for use in the preparation of an insulating material, in the form of a moist dough produced by a method as claimed in any of Claims 32, 33 or 34.

40. A chemical composition for use in the production of an insulating material, substantially as hereinbefore described, with reference to the examples.

41. An insulating material substantially as hereinbefore described with reference to the examples.

42. A method of manufacturing a composition for use in the production of an insulating material, substantially as hereinbefore described with reference to the examples.

43. A method of producing an insulating material substantially as hereinbefore described with reference to the examples.