GB2042551A - Epoxy resin coating or sealant compositions - Google Patents

Epoxy resin coating or sealant compositions Download PDF

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Publication number
GB2042551A
GB2042551A GB7906154A GB7906154A GB2042551A GB 2042551 A GB2042551 A GB 2042551A GB 7906154 A GB7906154 A GB 7906154A GB 7906154 A GB7906154 A GB 7906154A GB 2042551 A GB2042551 A GB 2042551A
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GB
United Kingdom
Prior art keywords
particles
fibres
epoxy resin
curing agent
composition
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB7906154A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Lingner and Fischer GmbH
Original Assignee
Lingner and Fischer GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Lingner and Fischer GmbH filed Critical Lingner and Fischer GmbH
Priority to GB7906154A priority Critical patent/GB2042551A/en
Publication of GB2042551A publication Critical patent/GB2042551A/en
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/22—After-treatment of expandable particles; Forming foamed products
    • C08J9/224—Surface treatment
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
    • C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J3/00—Processes of treating or compounding macromolecular substances
    • C08J3/24—Crosslinking, e.g. vulcanising, of macromolecules
    • C08J3/241—Preventing premature crosslinking by physical separation of components, e.g. encapsulation
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D163/00—Coating compositions based on epoxy resins; Coating compositions based on derivatives of epoxy resins
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J163/00—Adhesives based on epoxy resins; Adhesives based on derivatives of epoxy resins
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2325/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Derivatives of such polymers
    • C08J2325/02—Homopolymers or copolymers of hydrocarbons
    • C08J2325/04—Homopolymers or copolymers of styrene
    • C08J2325/06—Polystyrene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2363/00—Characterised by the use of epoxy resins; Derivatives of epoxy resins

Abstract

A coating or filling composition comprises a mass of particles or fibres, for example polystyrene beads, polyethylene particles, cellulose fibres or sawdust, some of which are coated with epoxy resin, and some with curing agent. Those carrying epoxy resin and/or those carrying curing agent are dusted with an inert powder such as talc, cement powder, starch or calcium hydroxide to form dust layers which prevent curing when the particles or fibers are in contact. The composition is mixed with water, for example, prior to use to disturb the powder layers and permit curing. The curing agent and/or epoxy resin may contain an emulsifier and the composition may contain small quantities of supplementary adhesive.

Description

SPECIFICATION Coating or sealant compositions This invention relates to coating compositions comprising a mass of particles or fibres intended to be applied adhesively to a surface; to a method of applying a mass of particles or fibres adhesively to a surface; and to a method of preparing a mass of particles or fibres including an inactive but activatable adhesive.
There are occasions when it would be desirable to apply a mass of particles or fibres adhesively to a surface.
For example, it would be desirable if particles of heat insulating material, such as blown polystyrene beads, could be applied to a surface to build up an adherent layer of heat insulation on the surface.
Such a method could provide an alternative to the common technique of fixing preformed sheets of insulation to the surface, as in the insulation of walls and ceilings of buildings.
Another instance when the application of an adhesive mass of particles or fibres is desirable is in sealing fissures in surfaces, e.g. masonry.
Unfortunately, the choice of an adhesive binder for the mass of particles or fibres is not an easy matter.
Water soluble binders are unsuitable for work which will be exposed to the weather or requires washing; many adhesives are too slow in forming an adhesive bond; acid based adhesives have an adverse effect on the metal parts of the equipment used to apply the mass; and, of course, adhesives in general tend to make the mass sticky and difficult to apply.
The present invention is based on the realisation that the ideal binder for a mass of particles or fibres would be one which formed only a light bond as the particles were applied but developed a strong bond over a short period of time once the mass was in place on the surface. Such a binder would permit the mass to be worked easily during application but would provide strength and cohesiveness when in place.
A curing epoxy resin system would meet these requirements. However, with such systems the epoxy resin and the curing agent must be added to the mass in the correct proportions at the time of application. For large scale work such as building insulation, this creates problems in that relatively large quantities of resin and curing agent must be handled, in difficult outdoor conditions or in indoor conditions where poor ventilation can give rise to health hazards. In addition, the proportions of epoxy resin to curing agent cannot usually be accurately metered or mixed, either through lack of skill on the part of the workman or simply because of the quantities involved.
It is, therefore, an object of this invention to provide a mass of particles or fibres embodying a twopart epoxy resin curing system in which the epoxy resin and curing agent are prevented from reacting until the time when the mass is to be applied to a surface.
Accordingly, the present invention provides a composition comprising a mass of loose, waterinsoluble particles or fibres, some of which carry on their surfaces an uncured epoxy resin and some a curing agent for the epoxy resin, the particles or fibres carrying the epoxy resin and/or the particles or fibres carrying the curing agent being dusted with an inert powder such that a layer of powder covers the epoxy resin and/or curing agent.
The layers of powder covering the epoxy resin and/or curing agent effectively prevent curing taking place even when the particles are in contact. However, as soon as the layers of inert powder are disturbed or washed off the epoxy resin and curing agent come into direct contact and a great many "spot" bonds develop throughout the mass, giving cohesion to the mass as a whole. If water is used to wash the powder off, the residual water may tend to prevent or inhibit curing unless the epoxy resin and/or curing agent is mixed with an emulsifier. The emulsifier promotes dispersion of the resin and curing agent coated particles or fibres and promotes contact between curing agent and resin, with the result that the bonds develop more readily. Hence, it is preferred that an emulsifier be present in the resin and/or curing agent.
Epoxy resins and curing agents are, of course, well known articles of commerce. The epoxy resin may be a normal bisphenol A-epichlorohydrin resin and the curing agent a normal polyaminoamide hardener. Suitable resins include those available under the trade names DER 331 ex Dow Chemicals, Eurepox 710 ex Shering AG. and Epicote 828 ex Shell Chemicals. Suitable curing agents include Casamid 360 (Registered Trade Mark) ex Akzo Chemicals, XE 435 ex Scherling AG. and Beckopox VEH 661 ex Hoechst AG., all three of which contain emulsifier.
It will be appreciated that not all the particles or fibres in the mass need necessarily carry epoxy resin or curing agent. A small proportion of "bare" particles or fibres can be caught up in the mass as a whole without undue adverse effects on the strength of the mass after the curing process is complete. The proportion of such "bare" particles or fibres which can be tolerated will vary according to the use to which the mass is to be put. Load bearing or thick vertical layers will require greater strength and therefore a lower proportion of "bare" particles than non-load bearing or thin horizontal layers.
Usually more than 90%, and preferably more than 95% of the particles or fibres should carry epoxy resin or curing agent.
It will also be appreciated that the proportions of particles or fibres carrying epoxy resin and curing agent should be approximately equal. If a substantial excess of particles or fibres carried epoxy resin, for example, there would be domains in the mass where only epoxy resin-carrying particles or fibres were in contact, and in those domains, no curing could take place. The resultant mass would lack strength.
Again, the extent to which such domains can be tolerated will depend on the use to which the composition is to be put, but in general the proportion of epoxy resin-carrying particles or fibres: curing agent carrying particles or fibres should usually be in the range 3:2 to 2:3, preferably approximati?lyl il.
The inert powder used in the composition of the invention may be either water soluble or water insoluble. However, it should not be soluble to any appreciable extent in the epoxy resin or curing agent. The requirement is that it form a film or layer over the resin and/or curing agent. Suitable inert powders are calcium hydroxide, cement powder, talc, starch and the like. The powder should have a very small particle size so that it can dust the parti cles or fibres readily.
Although curing is prevented when only those par ticles or fibres carrying resin or curing agent are dusted with care and with sufficient powder, it is preferred that both kinds are dusted.
It is probably inevitable that the powder will pick up small quantities of resin or curing agent from the particles or fibres. When the powder film is disturbed on application of the mass, the powder parti cles themselves will mix and curing will take place between powder particles as between the larger particles or fibres. This contributes to the overall cohesiveness of the cured mass.
The particles or fibres present in the composition of the invention can be ofanywater-soluble material. For heat insulation purposes it is possible to use blown polystyrene beads, ofthewell-known commercially available variety. They are effectively tiny balloons consisting of a skin of polystyrene and varying in size for example from about 0.5mm up to about 4mm, and weight about 12 to 15 gm/litrn. For use as a fissure sealant, the particles or fibres might be sawdust, polyethylene particles, cellulose fibres and the like. The invention however is not limited to compositions containing particles or fibres of any particlar material or of any particular size range.
To prepare a composition according to the invention, a first quantity of water-insoluble particles or fibres is mixed with epoxy resin and a second quantity with curing agent for the epoxy resin, inert powder is then mixed with the first and/or second quantities of particles or fibres and the resultant first and second quantities of particles or fibres are then mixed together.
The amount of particles or fibres, epoxy resin and curing agent used in the process will depend on the strength required of the mass when applied to the surface, and the general guidance as to proportions given above applies. It is a matter of routine to test various quantities and proportions to ensure that the final coating is satisfactory.
The compositions of the invention can be sTored for many months in a stable, uncured condition, providing they are not washed with water or otherwise treated so as to disturb the powder layers. When the time comes for their application to a surface, a liquid is mixed with the dry mass in such a way as to wash the surfaces of the particles and disturb the powder layers. Most commonly, the dry mass may be placed in a receptical and water poured or sprayed onto the particles, possibly with agitation or stirring. Since the mass must be of a consistency to permit application to the work surface, it will generally be necessary to avoid using too much water since this would make the mass too liquid for easy application.Generally, enough water to give the mass an initial cohesion through surface tension forces will be enough if the mass Is to óe applied with a trowel or other spreading implementorfrom an injection nozzle. If the mass is to be sprayed, a little more water to ensure easy spraying can be used, but excess should be avoided to prevent the coating being washed from the surface as soon as it is applied.
Usually, the water added will make the dry mass "sticky" enough to adhere to the surface and provide an initial cohesion while the epoxy cure takes place.
However, where particularly thick coatings on vertical surfaces are required, the composition preferably includes a water activatable adhesive in addition to the epoxy resin and curing agent. This additional water activatable adhesive can be present in very small amounts, and therefore will not clog the application instrument. Its purpose is to increase the initial cohesion of the mass on application and not to provide other than a very minor contribution to the overall adhesion of the mass when dry.
After the coating has been applied to the surface it is left undisturbed so that the water may evaporate and the epoxy cure may develop.
The following Examples illustrate the invention: Example 1
Parts by weight Blown polystyrene beads ("Styropor" ex BASF or 2.8 "Styron" (Registered Trade Mark) ex Dow Chemicals) PARTA Epoxy resin (DER 331 ex Dow Chemicals) 9.5 Finely powdered calcium hydroxide 14.0 Blown polystyrene beads ("Styropor" or "Styron") 2.8 PART B Curing agent (Casamid 360 ex Akzo) 9.5 Finely powdered calcium hydroxide 23.6 Part A was prepared by stirring the polystyrene beads with the epoxy resin until the beads had been coated fairly uniformly with the resin.The powdered calcium hydroxide was then gradually incorporated portionwise with stirring until the beads were coated with the powder.
Part B was prepared in the same way using the ingredients shown.
Parts A and B were then mixed together with stirring to produce a homogeneous mass which could be stored for three months without curing.
On the addition of 37.8 parts by weight of water, poured onto the mass of beads and stirred, the resultant composition could be applied to a vertical wall, using a commercial spray gun, to produce a coating 3cm thick which cured to a cohesive adherent mass in twenty-four hours.
Example 2
Parts by weight Blown polystyrene beads ("Styropor" ex BASF or 2.1 "Styron" ex Dow Chemicals) PARTA Epoxy resin (Epicote 828 ex Shell) 11.5 Talcum powder 21.0 Blown polystyrene beads ("Styropor" or "Styron") 2.1 PART B Curing agent (VEH 661 ex Hoechst) 11.5 Talcum powder 28.0 Parts A and B were prepared and mixed as described in Example 1.Water(23.8 parts by weight) was added, again as in Example 1, and the resultant composition could be applied to a vertical wall to a depth of 4cm. It dried to a rigid adherent facing in one day.
Example 3 After incorporating 0.1-0.2 part by weight of polyacrylamide powder ("Reten" (Registered Trade Mark) ex Hercules) to part A or B orto the mixture of parts A and B in the compositions of Examples 1 and 2 the compositions were found to stick more positively to the vertical wall during application. There was no adverse effect on the dry storage properties of the composition.

Claims (8)

1. A composition comprising a mass of loose, water-insoluble particles or fibres, some of which carry on their surface an uncured epoxy resin and some a curing agent for the epoxy resin, the particles or fibres carrying the epoxy resin and/orthe particles or fibres carrying the curing agent being dusted with an inert powder such that layer of powder covers the epoxy resin and/or curing agent.
2. A composition as claimed in claim 1 wherein the particles or fibres carrying epoxy resin and the particles or fibres carrying curing agent are dusted with an inert powder.
3. A composition as claimed in claim 1 or claim 2 wherein an emulsifier is present in the epoxy resin and/or curing agent.
4. A composition as claimed in claim 1 wherein the particles or fibres are blown polystyrene beads.
5. A composition as claimed in claim 4 wherein the beads have an average size in the range 0.5mm up to about 4mm.
6. A composition as claimed in any one of claims 1 to 3 wherein the particles or fibres are sawdust, polyethylene particles or cellulose fibres.
7. A process for the preparation of a composition as claimed in claim 1 wherein a first quantity of water-insoluble particles or fibres with epoxy resin and a second quantity with curing agent for the epoxy resin, inert powder is then mixed with the first and/or second quantities of particles or fibres and the resultant first and second quantities of particles or fibres are then mixed together.
8. A process for applying a heat insulating coating to a surface comprising mixing a composition as claimed in claim 4 or claim 5 with water, and spraying the resultant fluid mass onto the surface.
GB7906154A 1979-02-21 1979-02-21 Epoxy resin coating or sealant compositions Withdrawn GB2042551A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB7906154A GB2042551A (en) 1979-02-21 1979-02-21 Epoxy resin coating or sealant compositions

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB7906154A GB2042551A (en) 1979-02-21 1979-02-21 Epoxy resin coating or sealant compositions

Publications (1)

Publication Number Publication Date
GB2042551A true GB2042551A (en) 1980-09-24

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB7906154A Withdrawn GB2042551A (en) 1979-02-21 1979-02-21 Epoxy resin coating or sealant compositions

Country Status (1)

Country Link
GB (1) GB2042551A (en)

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