AU753786B2 - Glycerol-based fluidifying substance - Google Patents

Description

1/1 1 GLYCEROL-BASED FLUIDIFYING SUBSTANCE 2 3 Inert substances are commonly employed to fluidify the 4 pre-set component of a load-bearing polymerisable composition, and can be used as liquid carriers for 6 polymerisation initiators therein. However, after 7 polymerisation the composition contains entrapped 8 molecules of the inert liquid substance, which 9 adversely affect mechanical properties of the set 10 composition, by for example lowering its strength and 11 creep resistance, thereby reducing the capacity of the 12 composition to withstand sustained loading.

13 14 Water may be used as the inert liquid substance and has a relatively small effect on mechanical properties of 16 the set composition, for a similar level of 17 incorporation to other inert liquid substances.

18 However, the volatility of water at ambient 19 temperatures and humidities can lead to undesirable 20 drying out or increased viscosity of the pre-set 21 components of the composition in which it is 22 incorporated.

23 24 Other than water, inert liquid substances, which have been used to fluidify the pre-set component of a 2 1 polymerisable composition, have been typically certain 2 esters of carboxylic acids such as di-alkyl phthalates, 3 long-chain alkyl benzoates, chlorinated hydrocarbons 4 such as the CERECLOR (TM) range (Imperial Chemical Industries), glycols such as propylene glycol, 6 polyglycols such as polyethylene glycol or 7 polypropylene glycol or silicone oils and blends 8 thereof.

9 In addition to their unfavourable effect on the 11 mechanical properties of the set composition, these 12 substances compared with water are almost invariably 13 more toxic to health and the environment. They also 14 confer an inferior thermal stability to certain preferred free radical initiator(s) dispersed within 16 them. Furthermore, some of the inert substances are 17 immiscible with water so water cannot then serve as a 18 convenient flushing fluid in the preparation or use of 19 the composition.

S.21 Glycerol is known in the pharmaceutical field to be 22 used in certain pharmaceutical compositions as a 23 carrier for di-benzoyl peroxide, a known polymerisation 24 initiator. Glycerol is a fluid of low toxicity and is also a medium in which di-benzoyl peroxide has 26 stability against self-decomposition at elevated 27 ambient temperatures. With regard to these attributes 28 glycerol is a suitable inert liquid substance S. 29 conventionally employed in the pharmaceutical field.

31 Surprisingly it has now been found that glycerol may be 32 used as a very effective fluidifying element of a 33 substance to fluidify the pre-set component of a load- 34 bearing, and indeed any general non-pharmaceutical polymerisable composition such as a grout or adhesive.

36 Hence, it is an object of the present invention to 11 12 13 14 16 17 18 19 20 21 22 23 *24 26 27 28 29 :30 31 32 o. .33 34 36 provide an improved substance to fluidify the pre-set component of a non-pharmaceutical polymerisable composition such as a grout or adhesive.

According to one aspect of the present invention there is provided a fluidifying substance for a nonpharmaceutical polymerisable composition wherein the substance is or includes glycerol.

In one embodiment the substance wholly or substantially comprises glycerol. The substance may comprise glycerol along with 0-10, possibly 0-9.5, parts by weight of water.

Where the composition includes a polymerisation initiator the glycerol and water mixture is preferably employed wholly or substantially as a liquid carrier for the initiator.

Preferably the polymerisation initiator is a diacyl peroxide such as di-benzoyl peroxide.

Optionally, to accelerate the initiating action of the initiator, an accelerator is incorporated into one of the components that does not contain the initiator in a multi-component polymerisable composition.

Preferably the accelerator for di-benzoyl peroxide initiator is a tertiary amine, eg N,N-diethyl aniline or N,N-dimethyl para-toluidine.

Optionally the glycerol and water mixture includes one or more reagents to alter the reactivity of the polymerisation initiator.

Preferably the further reagent is di-butyl phthalate 4 1 (preferably a 5% solution), which quickens the onset of 2 gelation of the polymerisable liquid after this has 3 been inter-mixed with the di-benzoyl peroxide based 4 component.

6 other inert liquid substances which optionally may 7 constitute a minor part of the glycerol-based substance 8 may for example be any of those materials which 9 conventionally have been employed as a liquid carrier for such an initiator.

11 12 Preferably the other liquid materials should constitute 13 no more than 20% by weight of the total quantity of 14 inert liquid fluidifying substance.

16 when water is part of the composition, some or all of 17 it may be admixed with the glycerol part.

18 19 Optionally when water is present in the glycerol-based e**20 substance, water compatible ingredients may be 21 incorporated into the glycerol mixture so as to modify 22 its properties. For example, incorporation of clay or **23 water-soluble polymer such as C2ARBOPOL (TM) (B F 24 Goodrich) can modify its rheology.

The fluidifying substance of the present invention can be used to fluidify a one-component polymerisable 28 composition. It can also be used to fluidify one or :.29 more components of a multi-component polymerisable composition.

31 ::32 A one-component form of such a composition may be formulated, setting being effected by, for example, the 34 application to the composition of heat or radiation such as ultra-violet rays, gamma rays or electron beam, 36 optionally aided by the incorporation of a latent S U( 4 1 initiator substance(s) in the composition.

2 3 According to a second aspect of the present invention, 4 there is provided a non-pharmaceutical polymerisable composition having at least one pre-set component, 6 wherein the component is fluidified by a substance 7 which is or includes glycerol.

8 9 In a preferred embodiment of the invention there is provided a composition, comprising a polymerisable 11 ethylenically unsaturated liquid substance, within 12 which prior to the onset of this polymerisation is 13 incorporated a mixture of glycerol and water within the 14 range of 0.1 to 50% by weight of the substance, wherein the mixture includes 0-10 parts by weight of water in 16 ratio to I part of glycerol.

17 18 The glycerol-based fluidifying substance mixture 19 constitutes the sole or major part by weight of inert 20 liquid substance incorporated in the composition. The 21 composition after polymerisation is capable of enduring t 22 at ambient temperatures an unconfined compressive 23 stress of at least 40 Newtons per square millimetre 24 without fracture.

26 Preferably the ethylenically unsaturated liquid 27 substance is either a liquid monomer, a mixture of 28 liquid monomers or a liquid polymer/oligomer ester of 29 acrylic acid or methacrylic acid, or a blend of these, optionally incorporating a dissolved ethylenically 31 unsaturated polymer/oligomer.

32 33 Examples of monomer are, non-exclusively, styrene, 34 substituted styrene such as tertiary-butyl styrene or para-bromo styrene or vinyl toluene or para-methyl 36 styrene or divinyl benzene or alpha-methyl styrene, -6alkyl and hydroxyalkyl esters or acrylic acid or methacrylic acid or crotonic acid or maleic acid or fumaric acid or vinyl sulphonic acid, allyl esters of carboxylic acids such as diallyl phthalate, etc or any blend of these. Examples of liquid or solid polymer/oligomer are, non-exclusively, fumarate/maleate based polyester, epoxy acrylate, epoxy methacrylate, urethane acrylate, urethane methacrylate, novolac epoxy acrylate, novolac epoxy methacrylate etc or any blend or hybrid of these.

Preferably any polymerisation initiator used in the composition is di-benzoyl peroxide.

According to a third aspect of the present invention, there is provided a method of fluidifying one or more components of a non-pharmaceutical polymerisable composition wherein the one or more components are admixed with a substance which is or includes glycerol.

In formulating the preferred embodiment of the invention any of the materials which are typically employed in commercial compositions based on polymerisable ethylenically unsaturated substances may be employed.

Such materials may be chemically reactive, for example accelerators, inhibitors or chain transfer agents may be incorporated into a component of the composition that does not comprise the initiator, except in the case of one component systems. Inhibitors retard the rate of polymerisation and can also prolong the storage life of the resin based component of the composition, an example being hydroquinone. Chain transfer agents limit the length of the polymer chains formed during setting of the composition, an example being dodecyl mercaptan.

Such materials may also be chemically inert, for example particulate solid fillers, rheology modifying agents, shrinkage or expansion additives, air release agents, fibres or pigments.

In a further embodiment of the invention there is provided a composition as herein described for use as a grout/adhesive for embedding, bonding or fixing a reinforcement element, for example a high strength tendon or plate, onto or into a construction material, for example concrete or masonry or ground strata.

In a yet further embodiment of the invention there is provided a composition as herein described for use as an adhesive/patching mortar, an in situ flooring material, a vehicle body repair compound, protective coating or as a cast or moulded article.

The present invention is generally useful in loadbearing compositions. The present invention is certainly suited to uses where the set product is required to withstand high/sustained stress in service.

In the use of a composition for "permanent" grouting of a fixing or reinforcement tendon in the substrate, a low tendency to creep is a particularly important requirement. If the set composition is not resistant to creep, the grouted fixing/tendon may undergo an undesirable relaxation in stress from its initial value and/or undergo an undesirable irrevocable strain during its service lifetime. Further, if the composition continually experiences stress at values for which it cannot resist creep, the composition will eventually fracture.

'1

S..

S.

The use of glycerol as an inert liquid substance is particularly beneficial with regard to limiting the effects on mechanical properties whenever a high proportion of inert liquid substance relative to polymerisable liquid substance is desired. For instance, a relatively high level of inert liquid substance may be.desired in order to facilitate the physical intermixing of two components of a capsule or cartridge bonding composition at the point of use, or to assist the flow or proportioning of the components of a pumpable or pourable form of the composition.

Several embodiments of fluidifying substances according to the present invention exhibit improved qualities over previous fluidifying agents. The use of a glycerol based fluidifying substance means that the fluidifying substance is non-toxic, has a small effect on the mechanical properties of the set composition within which it is used, and water can be used as a flushing medium for the prepared compositions. In addition not only does the glycerol based fluidifying substance provide both resistance to chemical attack and a stable medium for radical polymerisation initiators, but also, because of the low volatility of glycerol, the glycerol based fluidifying substance does not have the problems of a water based fluidifying agent, namely those of drying out and high viscosity of the pre-set composition.

Whilst any known method may be employed for initiating the setting of a polymerisation composition, a free radical mechanism is often employed. A free radical initiator is normally incorporated in the composition for this purpose, and in the pre-set state of the composition it is incorporated, except in one component compositions, in a separate component to that A I 9 1 comprising the polymerisable liquid substance.

2 Representative examples of free radical initiators are: 3 diacyl peroxides, such as dibenzoyl peroxide or bis 4 (2,4 dichlorobenzoyl) peroxide or di-lauroyl peroxide; tertiary butyl peroxy 2 ethyl hexoate; cumene 6 hydroperoxide; peresters, such as tertiary butyl 7 perbenzoate; azo compounds, such as 8 azodiisobutyronitrile; keto peroxides, such as methyl 9 ethyl ketone peroxide. In order to accelerate the generation of free radicals from such initiators,.an 11 accelerator is commonly employed in one of the other 12 components, representative examples being tertiary 13 amine, such as N,N-dimethyl aniline and N,N-dimethyl 14 para-toluidine, aldehyde-amine condensation product, organic sulphonyl chlorides, organic salts of a 16 transition metal, such as cobalt naphthenate and copper 17 octoate or mixtures thereof. The free radical 18 initiator is typically incorporated at about 0.5% to 19 about 3% by weight of the polymerisable substance.

21 The invention is illustrated by reference to the 22 following example.

23 24 Example 1 26 The composition of the invention may be based on two 27 components of the formulation described as an example 28 of a rock bolt capsule composition in Great Britain 29 Patent No. 2274894. The two components of the composition, in its pre-set state, are the Resin 31 component R, and the Catalyst component C. Both 32 components have the physical form of a liquid paste, so 33 enabling R and C to be pumped into the large and small 34 compartments respectively of an elongated twincomponent capsule. The ratio of R to C per unit length 36 of capsule may be varied within the range 10/1 to 35/1 t 4 by weight. The formulations of R arnd C are as follows-.

Ingredient Weight Weight Type Resin component R Ethylenically CRYSTIC 3601A (TM) unsatu rated liquid substance styrene monomer part 9 8.0-12.0 (essential reactant) polyester part 11 8.0-1 Ethylenically unsaturated

N

7 N-diethylaniline 0.2 0.05-0.40 polymer (tertiary amine) (essential reactant) Polymerisation CABOSIL M5 9TM) 0.3 0.1-0.4 accelerator (pyrogenic silica) (essential reactant) 50:50 Blend of TRTJCARB 298 (TM) 79.5 65-83 Rheologyand TRUCARB 52 (TM) control agent (powdered limestone mineral) (auxiliary) Particulate inert filler (auxiliary) Catalyst component, C. Polymerisation initiator LUCIDOL DAMPED (TM) (essential (di-benzoyl peroxide part) 10 5-20 reactant) LUCIDOL DAMPED (TM) 3.3 Inert liquid (water part) )liquid 15-30 substance Water )plasticizer 2.7 predominantly Glycerol )19 glycerol (water) (essential TRUCARB 170 )powdered 45 50-80 fluidifier for C) SNOWCAL 30 (TM) )mineral Particulate inert filler I The set composition, made by intermixing these 2 components in the ratio R/C within the range 10/1-35/1 3 by weight, has an unconfined compressive strength in 1 excess of 80 Newtons per square millimetre after 24 2 hours at 20 0 C, measured according to British Standard 3 test method 6319. This strength makes the composition 4 useful for the permanent fixing of a mechanically stressed rock bolt.

6 7 One use of the composition of the invention is as a 8 grout for anchoring/bonding a fixing element into or 9 onto concrete or masonry or ground strata. Settable compositions based on a polymerisable ethylenically 11 unsaturated liquid substance have been extensively used 12 world-wide for this purpose for over 30 years. For 13 this use it is commnon practice to formulate the 14 composition in the form of two components: component comprises the polymerisable liquid substance, a 16 polymerisation accelerator, particulate inert filler 17 and a rheology modifying agent; component comprises a free radical polymerisation initiator, inert liquid .19 substance, particulate inert filler and a rheology 20 modifying agent. For convenience, the components are .21 commonly packaged in the separate components of a .22 capsule or cartridge, and the composition is caused to 23 set after a short delay simply by intermixing 24 components and immediately prior to placement of the composition. The components of a capsule can be intermixed by rotating the fixing element axially 27 through the capsule, whilst those of a cartridge can be :28 intermixed by co-extruding them through a static mixer in a nozzle attached to the cartridge.

w 31 use of a glycerol-based substance as the inert liquid substance of the above composition upgrades the 33 mechanical properties of the set product so that the 34 product is more able to bear mechanical stress without structural impairment during its expected service 36 lifetime.

Claims (7)

12- The Claims Defining the Invention are as Follows 1. A load-bearing settable two-part composition incorporating a radical polymerisable ethylenically unsaturated liquid substance in a first part, and glycerol in a second part, along with a polymerisation initiator substance(s) in said second part. 2. A composition as claimed in claim 1, which, when set, is capable of enduring, at a temperature of between -10 and +40 degrees Centrigrade, an unconfined compressive stress of at least 40 Newtons per square millimetre without fracture. 3. A composition as claimed in claim 1 or 2, wherein the radical polymerisable ethylenically unsaturated liquid substance is either a liquid monomer(s) or a liquid polymer/oligomer ester of acrylic or methacrylic acid, or a blend of these, and wherein the ethylenically unsaturated liquid substance may optionally incorporate a dissolved ethylenically unsaturated substance(s). 4. A composition as claimed in any one of claims 1 to 3, wherein the polymerisation initiator is a diacyl peroxide. 5. A polymerisation intiator as- claimed in claim 4, wherein the diacyl peroxide is di-benzoyl peroxide. 6. A composition as claimed in any one of claims 1-5 which incorporates an 20 accelerator substance in the first part. 7. A composition as claimed in claim 6, wherein the accelerator substance is a polymerisation accelerator substance and is incorporated into a componentn of the composition that does not contain the initiator. 8. A composition as claimed in claim 7, wherein the polymerisation accelerator substance is a tertiary amine. -13- 9. A composition as claimed in claim 8, wherein the polymerisation initiator is di- benzoyl peroxide, and the accelerator is N, N-diethyl aniline or N, N-dimethyl para-toluidine. A two part settable composition as claimed in any one of claims 1-9, wherein either one or both of the parts comprises water and wherein the total weight of water does not exceed 10 times the weight of glycerol. 11. A two-part settable composition as claimed in any one of claims 1-9, wherein either one or both parts comprises any other non-polymerisable liquid substance(s) apart from glycerol, and wherein the total weight of such substance(s) does no exceed the weight of glycerol. 12. A composition as claimed in claim 10, wherein glycerol comprises 2-98% of the total weight of the second part, 2% occurring when glycerol comprises about 1/10 of the total weight of glycerol plus water, and 98% occurring when glycerol is the only ingredient present in the second part apart from the initiator

13. A composition as claimed in claim 11, wherein glycerol comprises 10-98% of the total weight of the second part, 10% occurring when glycerol comprises °*°about 1/2 of the total weight of glycerol plus other non-polymerisable liquid substance(s), and 98% occurring when glycerol is the only ingredient present in the second part from the initiator

14. A composition as claimed in any one of claims 10 to 13, which comprises a non-polymerisable liquid substance which is an ester of a carboxylic acid and an alcohol or glycol or polyol. A composition as claimed in claim 10, wherein the only other non- 25 polymerisable liquid substance, apart from glycerol, is water. -14-

16. A composition as claimed in any one of claims 1-15, suitable for use as a grout/adhesive from embedding, bonding or fixing a reinforcement element onto or into a construction material or ground stata.

17. A composition as claimed in any of claims 1-15, suitable for use as an adhesive/patching mortar, an in-situ flooring material, a vehicle body repair compound, a protective coating or as a cast or moulded article.

18. A method of fluidifying one or more components of a non-pharmaceutical polymerisable composition wherein the one or more components are admixed with a substance which is or includes glycerol.

19. A method as claimed in claim 18, wherein the one or more components are admixed with a substance comprising glycerol and up to 10 parts water. Dated this THIRTEENTH day of JUNE 2002. **Exchem plc o*l Applicant Wray Associates Perth, Western Australia Patent Attorneys for the Applicant g o o **e