CA2143426A1

CA2143426A1 - Process for employing a synthetic resin system

Info

Publication number: CA2143426A1
Application number: CA002143426A
Authority: CA
Inventors: Hans Mehesch; Wolfgang Cornely; Martin Fischer
Original assignee: Individual
Current assignee: Bergwerksverband GmbH
Priority date: 1992-08-25
Filing date: 1993-08-24
Publication date: 1994-03-03
Also published as: PL307609A1; WO1994004588A1; DE4228178A1; AU4951993A; ZA936218B; DE59305796D1; EP0656917A1; SK24995A3; CZ45595A3; AU674162B2; EP0656917B1; CN1087661A; PL173938B1; CZ288167B6; ATE150042T1

Abstract

A process for using a polyurethane-based synthetic resin system in which the system consists of an isocyanate component a) and a polyol component b) and auxiliaries and additives c) can be added to the components a) and/or b) and the polyol component b) contains an insufficient proportion of primary or secondary di or polyamines. The system is used to insert and secure roof bolts in boreholes and to that end is preformulated as a two-part system with components a) and b), possibly including auxiliaries and ad-ditives c), the components a) and b), possibly including auxiliaries and additives c), the components a) and b) are mixed together shortly before introduction into the boreholes and the mixture spontaneously undergoes an increase in its viscosity to form a gel-like substance which secures the roof bolts in the boreholes and then slowly hardens.

Description

--" 21g3426 ,., ,-'`_,~

-PROCESS FOR EMPLOYING A S~NTHETIC RESIN SYSTEM

The invention relates to a process for employing a polyurethane-based synthetic resin system, wherein the system comprises an isocyanate component a) and a polyol component b), and auxiliary and additive agents c) can be added to components a) and/or b), and the polyol component b) contains a deficient proportion of primary or secondary di- or polyamines. Synthetic resin systems of this kind are known, for instance from Published, Non-Examined German Patent Application DE-OS 36 10 729. They are used to prepare coating and sealing means that harden under the influence of moisture in the air.
To secure anchor bars in rock climbing, it is already known to use so-called bonded anchors, in which the bonding is done with two-component synthetic resin systems. One possible way is to introduce the resin components into the drilled hole in separate cartridges, into which the anchor bar is then thrust, destroying the cartridges, and the hardenable mixture is produced by rotation and after hardening firmly holds the anchor by bonding it to the rock.
The hardenable mixture may, however, also be forced into the drilled hole, using a pump, before or after the introduction of the anchor bar.
Particularly with drilled holds made overhead, the problem exists that some of the resin mixture sometimes flows back into the drilled hole, so that the anchor is bonded only inadequately in place.
The object of the invention is to overcome this disadvantage in the mounting of bonded anchors.
According to the invention, this object is obtained by . _ . . ' ~ _ _ . , ~ _, _ ~., . __. _ _ . _ =_ . __` ___ _ __ _ , _ _ _ ~ _= _ , _ ~ ~ _ -- -- _ _==, _ . ~ = ~ . _ . . _' .~,_ . _ _ ~ . . . _ . ~ _ _ _ , _ _ _ f _ _ _ ~ . ~_------~---- -- . ---- -- _ ~ _ _ _ ~ _ ~_ _ . . , ' . : _, ~ - ;' _ _ ~ - _ _; _ ~ _ ~_~ ' _ ~ ~ ', . _ _ ~' - . . _ I -. . ' ' ., _ _ _ .--_ _ _ _ _ _ = _ _ ~ _ _ _ _ _ _ , _, _ _ =
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the characteristics of the body of claim 1. It has surprisingly been demonstrated in experiments that the two-component synthetic resin mixture according to the invention, with gel-like consistency, is readily pumped and can also be introduced easily into drilled holes oriented upward, so that once it has arrived at the innermost point of the drilled hole, it will not flow back out again by gravity before hardening. It is also extremely surprising that the two-component mixture has an adequate load-bearing force to firmly hold the bonded anchor in the drilled hole until hardening.
Further features are recited in the dependent claims.
The polyisocyanate component a) to be used in the process of the invention preferably involves polyphenylene-polymethylene-polyisocyanates, as prepared by aniline/formaldehyde condensation and ensuing phosgenation (~polymeric MDI " ), or derivatives, which are liquid at room temperature and have carbodiimide, biurethane, urethane and/or allophanate groups, of these polyisocyanates and their prepolymers, that is, conversions products of polyisocyanates with polyols in deficiency. Compounds generally known from polyurethane chemistry, preferably long-chain polyols with hydroxyl numbers below 150 mg KOH/g of substance, can be considered as polyols for preparing prepolymers. The polyisocyanate mixtures ("polymeric MDI") that are liquid at room temperature and are obtained by phosgenation of aniline/formaldehyde condensates, as well as their liquid conversion products, having NCO groups, of the polyisocyanate mixtures with deficient quantities (molar ratio of NCO/OH =
1:0.005 to 1:0.3) of multivalent alcohols with a molecular ~14~4~6 weight range from 62 to 3000, in particular polyols having ether groups and having a molecular weight range from 106 to 3000, are preferred. mixtures, which are liquid at room temperature, of 2,4'- and 4,4'-diisocyanatediphenylmethane are likewise suitable as polyisocyanate components a). In principle, however, according to the invention other polyisocyanates are also possible, such as those known from German published, non-~m1ned patent application DE-OS 28 32 253, pages 10 and 11. Highly preferably, polyisocyanate mixtures of the diphenylmethane series having a viscosity at 25C of from 50 to 5000 mPa s with an NCO content of approximately 30 to 32 weight % are used.
The polyol component b) involves mixtures of organic polyhydroxyl compounds with hydroxyl numbers between 30 and 2000, where the hydroxyl number of the mixture is between 200 and 500 mg KOH/g of substance.
The polyhydroxyl compounds preferably involve the polyether polyols, known per se from polyurethan chemistry, or mixtures of various polyetherpolyols of this type.
Examples of readily usable polyether polyols are propoxylation products of bivalent to octovalent starter molecules, such as water, 1,2-dihydroxypropane, trimethylolpropane, pentaerithritol, glycerine, sorbitol, ethylene diamine and optionally cane sugar. In general, component ti) has a mean hydroxyl functionality of 2.0 to 5.0, preferably 2.0 to 3. Suitable mixtures of this kind may for instance be obtained in that corresponding mixtures o~ starter molecules of the type given here as examples are sub~ected to a propoxylation reaction. However, it is also possible for separately prepared polyhydroxylpolyethers to be 21434~6 mixed together after their preparation as the component (i) to be used according to the invention.
As amines according to the invention, primary or secondary di- or polyamines and mixtures thereof are used.
Examples of suitable aromatic amines are: 4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dichloro-4,4'-diaminodiphenylmethane, 1,3,5-triisopropyl-2,4-diaminobenzene, 1-methyl-3,5-diethyl-2,4-diaminobenzene, 1-methyl-3,5-diethyl-2,6-b, 1,3,5-triethyl-2,4-diaminobenzene and technical mixtures with the last three compounds named, 3,5-di(methylthio)-2,4-toluenediamine, 3,5-di(methylthio)-2,6-toluenediamine and technical mixtures of them, 1,2-ethylene di-(4-amino)thiophenol ether, 1,3-propanediol di(p-amino)benzoate, 3,5-diamino-4-chlorobenzoic acid isobutyl ester, 1,3-propylene di-(4-amino)benzoate.
Examples of suitable cycloaliphatic amines are:
isophorondiamine, 4,4,-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminocyclohexylmethane, N-cyclohexyl-1,3-diaminopropane, N-($-aminoethyl)piperazine.
Examples of suitable aliphatic amines are:
diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diisopropyltriamine.
The following substances can be used as auxiliary and additive agents c) conventional in polyurethane chemistry:
- Catalysts for accelerating the various isocyanate addition reactions, in particular such as bismuth- or tin-organic compounds, such as dibutyl tin dilaurate, organic alkali salts such as potassium acetate, or tertiary amines, such as triethylenediamine, dimethylethanolamine, or N-., . . . :.

21~426 :'.
.

ethylenemorphylene. These catalysts are generally jointlyused in a quantity of up to 2 weight ~, preferably in a quantity of from 0.1 to 1 weight ~, referred to the total mixture.
- Water traps for preparing non-foaming or low-foam products, such as zeolite paste, which are used in a quantity between 0.2 and 10 weight ~, preferably between 1 and 5 weight ~.
- Foam regulators, that is, foam stabilizers or destabilizers, preferably on a polysiloxane base. They are used in a quantity of up to 2~, preferably between 1 ppm and 1000 ppm, referred to the total mixture.
- Optionally water as a propellant, which can be used in quantities of up to 5 weight ~, preferably 0.5 to 2 weight .
- Optionally, physical propellants, such as partially halogenated hydrocarbons or other volatile compounds, such as dichlorofluoromethane or pentane, of which up to 20~ can be added.
- optionally, organic or inorganic flame retardants, such as phosphoric esters or aluminum-hydroxide derivatives, in quantities of up to 20 weight ~ for liquid agents and 50 weight ~ for solid agents.
- Optionally, fillers, such as urea, ground quartz or talcum, in quantities of up to 50~.
In the reaction mixtures to be used in the process according to the invention, the various components are present in a quantity that corresponds to an isocyanate coefficient of from 90 to 150, preferably 120 to 140. The term "isocyanate coefficient" is understood here to mean the 214342~

quotient of the number of isocyanate groups present in the reaction mixture, divided by the number of groups present in the reaction mixture that are reactable with isocyanate groups, multiplied by 100; the water enters into the calculation as a difunctional compound.
Before the process according to the invention is carried out, generally the auxiliary and additive agents c) optionally to be jointly used are combined with the polyol component b), whereupon the processing by the two-component system ensues. This means that to produce the reaction mixtures, the polyisocyanate component a) is intensively mixed with the polyol component b), or with the mixture of the polyol component b) and the auxiliary and additive agents c). For this purpose, the mixing systems known per se in the prior art may be employed.

Description o~ the Process From anchor technology it is known that higher-viscosity two-component synthetic resin compositions are processed by means of metering pumps with a integrated pressure tank. Because of the viscosity of the two-component synthetic resin compositions, these pumps are not self-aspirating, and a higher injection pressure is required for the pressing operation. Because of the use of two-component synthetic resin compositions, the metering pumps in PUR rock fastening, which have already been introduced, can be employed. The low-viscosity single components of the two-component synthetic resin composition are aspirated by the metering pump and after mixing, for instance using a static ` 2~3426 mixture, react to make a higher-viscosity product, which can then be pumped only by using pressure. This mixed two-component synthetic resin composition, after hardening, bonds the commercially available injection anchor in the drilled hole, or bar anchors can be bonded in the drilled hole using the mortar process.
The exemplary embodiments below in accordance with tables 1-4 serve the purpose of further explanation of the process. All the percentages given are referred to composition percents.

EXAMPLES

In the examples of table 3 and 4, the starting components listed in tables 1 and 2 are used for the system components b) and c):

2~43426 Table 1 SyRtem Starting Hydroxyl number Viscosity components b) components ~mg ~OH/g] at 25 C
(mPa 8) Basic polyol I glycerine and380 450 propylene oxide Basic polyol II saccharose, 1,2-380 580 propanediol, propylene oxide Basic polyol III trimethylol propane 380 600 propylene oxide Flexibilizing 1l2-propanediol56 324 polyol I propylene oxide Flexibilizing ditto 260 73 polyol II
Flexibilizing butanediol 176 277 polyol III tetrahydrofuran Flexibilizing triethanolamine27 870 polyol IV propylene oxide Ethylene glycol - 1808 16 Diethylene glycol - - 1057 26 Glycerine - 1827 750 Castor oil 160 680 Diamine I (N-(~-aminoethyl)piperazine) Diamine II (N-cyclohexyl-1,2-diaminepropene) Diamine III (3,3'-dimethyl-4,4'-diaminocyclohexylmethane) Diamine IV technical mixture of 1,3,5-triethyl-2,4-diaminobenzene ~ 2~43~2~

.

TablQ 2 Sy8 tem components c) Starting cn~ron~nts Catalyst I dimethylethanolamine Catalyst II triethylenediamine, 33~ in ethylene glycol Catalyst III dibutyl tin dilaurate Catalyst IV potassium acetate Catalyst v 2,4,6-tris(dimethylaminomethyl)phenol Zeolite paste zeolite type .... 50~ in Castor oil 2~43426 :. .

From Tables 1-4 it is clear that for the two-component polyurethane system according to the invention, a wide range of starting components [verb missing], particularly for system component b) (Table 1), and also for system component c) (Table 2).
It is understood that besides the starting components listed others may also be suitable, because the components listed in Tables 1 and 2 involve merely those that are listed in changing compositions or formulations in Tables 3 and 4, to the extent that in experiment series in combination with the system components a) named in Tables 3 and 4 they have lead to suitable two-component polyurethane mixtures, which gel to a gel-like consistency in a fraction of a minute and are capable, in this quasi-thixotropic state, of reliably firmly holding an anchor in an upward-drilled hole until such time as a fastening action by bonding, which makes the anchor capable of holding a load, is attained within a setting time on the order of some minutes.

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Tables 3 and 4 list 10 examples, which contain the corresponding formulation instructions for assuring the aforementioned reaction results.
Example 11 lists a comparison example, in which system component b) was prepared without a diamine, with the composition otherwise similar to examples 1-10. When such a mixture was employed, the special effect of a rapidly ensuing gelation to a gel-like consistency or a quasi-thixotropic state, which enables an anchor to be firmly held in an upwardly inclined drilled hole, was not attained.
It can be seen from Fig. 1 that a rapid rise in viscosity within fractions of a minute is attained only with mixtures in which a diamine cross-linking agent, as illustrated in the mixture of example 4, is used, and that by comparison without diamine cross-linking agents, as demonstrated in example 11, only a gradual increase in viscosity occurs, so that this mixture is not capable of firmly holding an anchor in an upwardly inclined drilled hole.
In injection resins based on two-component polyurethane resins that do not form a gel-like consistency after the components are mixed together, seepage from the effect of gravity occurs when they are employed in markedly fissured rock. In the polyurethane system according to the invention, based on a two-component polyurethane, the system, after the low-viscosity individual components are mixed in a volumetric ratio of 1:1, after from 2 to 12 seconds becomes a lubricating greaselike product, which hardens after 4 to 5 minutes.

2~L~13~26 The system should be processed by the known injection technique for two-component polyurethane mixtures, so that no special metering pumps are needed.

Usaqe exam~le 12 (injection test) An injection anchor was inserted into a drilled hole in a moist synthetic rock (anhydride). The resin mixture with a gel-like consistency, with the upwardly oriented drill hole to be filled, emerged from the injection anchor at the innermost part of the drilled hole and had to be forced back again uniformly from the innermost point to the mouth of the hole, because on account of its gel-like (quasi-thixotropic) consistency it did not automatically flow downward under the influence of gravity. Fig. 2 shows the strain diagram of the anchor test. It shows the increase in force of the injection anchor. At a bonded-in length of 50 cm, the anchor was put under strain after a hardening time of 1 h. It was not possible to pull the anchor out of the drilled hole;
instead, it was broken off with a force of 250 kN.

Usaqe example 13 Strength tests were carried out on low-foam sample bodies. The following values were ascertained:

- compressive strength 20.4 N/mm2 - bending strain strength 5.2 N/mm2 - modulus of elasticity 1.1 kN/mm2 - density 695 kg/m3 .. . .

~1~3~26 Since in an annular gap, because of the greater flow pressure, the two-component polyurethane system does no~ foam up so markedly, it can be assumed that the strengths are even higher than the values given above.

Usaqe comparison example 14 with cable anchor In anchor work in in tight spaces, flexible cable or rope anchors are often used. The adhesive bond between these anchors in the rock is attained in that anchor mortar based on cement paste is injected into the drilled hole in the prior art, and the anchor is then thrust in by hand.
In the comparison example, a cable anchor 4 m in length was used, which has a squeeze binding that can hold an anchor plate, in order to anchor the rock face end on an edge of the rock face. ~ cement-based anchor mortar was used, which was stirred with water in a simple mixing and pumping device and introduced into the drilled hole via a feed hose. The consistency of the mortar was so viscous that it did not flow out of the steeply upwardly inclined holes. The cable anchors could be inserted by hand into the drilled hole filled with mortar.
The disadvantage of this anchor mortar is the comparatively complicated preparation of a suitable mortar consistency, the careful cleaning of the line paths of mortar residues that is needed thereafter by flushing with water, and the relatively late load-bearing action of the cement mortar, compared with the faster-binding resin-based bonding mixtures.

~ 214342~

Usaqe exam~le 15 with cable anchor The anchor setting test was done with the two-component polyurethane system in a 4 m long transparent plexiglas tube closed on both end. The tube was set up vertically and secured to a block of stone. In the test, a 4 m long cable anchor was thrust into the tube to its innermost point. A
plastic hose with an inside diameter of 6 mm was secured to the cable anchor. During the injection, a pressure loss of 35 bar occurred in the injection hose. After 30 seconds, the annular space between the anchor and the tube wall was entirely filled with polyurethane resin mixture. The resin mixture was so pasty that only a very slight portion of the gel-like (quasi-thixotropic) resin mixture flowed out of the tube opening, as can be seen from Fig. 3. This test entirely confirmed the excellent firm-holding property of the newly developed two-component polyurethane system during the initial gel-like (quasi-thixotropic) consistency state. In contrast to a cement mortar, the hardening process was ended incomparably faster, however, so that the load-bearing action of the anchor bonded with synthetic resin becomes effective very much earlier.

Claims

1. A process for employing a polyurethane-based synthetic resin system, wherein the system comprises an isocyanate component a) and a polyol component b), and auxiliary and additive agents c) can be added to components a) and/or b), and the polyol component b) contains a deficient proportion of primary or secondary di- or polyamines, characterized in that the system is used for inserting and securing roof bolts in drilled holes and to that end is preformulated as a two-component system having components a) and b), optionally including auxiliary and additive agents c); the components a) and b) are thoroughly mixed shortly before being introduced into the bore holes, and the mixture spontaneously undergoes an increase in its viscosity to a gel-like consistency which firmly holds the roof bolts in the bore holes, and then slowly hardens.

2. The process of claim 1, characterized in that polyphenylene-polymethylene-polyisocyanates, as prpared by aniline/formaldehyde condensation and ensuing phosgenation ("polymeric MDI"), are used as the polyisocyanate component a).

3. The process of claim 1, characterized in that derivatives, which are liquid at room temperature and have carbodiimide, biurethane, urethane and/or allophanate groups, of the polyisocyanates and their prepolymers, that is, conversions products of polyisocyanates with polyols in deficiency, are used as the polyisocyanate component a).

4. The process of claim 3, characterized in that compounds generally known from polyurethane chemistry can be considered as polyols for preparing prepolymers.

5. The process of claim 4, characterized in that long-chain polyols with hydroxyl numbers below 150 mg KOH/g of substance are used.

6. The process of claim 5, characterized in that polyisocyanate mixtures ("polymeric MDI") that are liquid at room temperature and are obtained by phosgenation of aniline/formaldehyde condensates are used.

7. The process of claim 6, characterized in that the liquid conversion products, having NCO groups, of the polyisocyanate mixtures with deficient quantities (molar ratio of NCO/OH = 1:0.005 to 1:0.3) of multivalent alcohols with a molecular weight range from 62 to 3000 are used.

8. The process of claim 7, characterized in that polyols having ether groups and having a molecular weight range from 106 to 3000 are used.

9. The process of claim 1, characterized in that polyisocyanate mixtures of the diphenylmethane series having a viscosity at 25°C of from 50 to 500 mPa . s with an NCO content of approximately 30 to 32 weight % are used.

10. The process of claim 1, characterized in that mixtures of organic polyhydroxyl compounds with hydroxyl numbers between 30 and 2000, where the hydroxyl number of the mixture is between 200 and 500 mg KOH/g of substance, are used as the polyol component b).

11. The process of claim 10, characterized in that mixtures of various polyether polyols are used as the polyhydroxyl compounds.

12. The process of claim 11, characterized in that propoxylation products of bivalent to octovalent starter molecules, such as water, 1,2-dihydroxypropane, trimethylolpropane, pentaerithritol, glycerine, sorbitol, ethylene diamine and optionally cane sugar are used as the polyether polyols.

13. The process of claim 11 or 12, characterized in that the polyhydroxyl compound has a mean hydroxyl functionality of 2.0 to 5Ø

14. The process of claim 13, characterized in that mixtures of starter molecules are subjected to a propoxylation reaction.

15. The process of claim 14, characterized in that separately prepared polyhydroxylpolyethers are mixed together after their preparation.

16. The process of claim 1, characterized in that primary or secondary di- or polyamines and mixtures thereof are used as the amines.

17. The process of claim 16, characterized in that 4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dichloro-4,4'-diaminodiphenylmethane, 1,3,5-triisopropyl-2,4-diaminobenzene, 1-methyl-3,5-diethyl-2,4-diaminobenzene, 1-methyl-3,5-diethyl-2,6 diaminobenzene, 1,3,5-triethyl-2,4-diaminobenzene and technical mixtures with the last three compounds named, 3,5-di(methylthio)-2,4-toluenediamine, 3,5-di(methylthio)-2,6-toluenediamine and technical mixtures of them, 1-2-ethylene di-(4-amino)thiophenol ether, 1,3-propanediol di(p-amino)benzoate, 3,5-diamino-4-chlorobenzoic acid isobutyl ester, 1,3-propylene di-(4-amino)benzoate are used as aromatic amines.

18. The process of claim 16, characterized in that isophorondiamine, 4,4,-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminocyclohexylmethane, N-cyclohexyl-1,3-diaminopropane, N-(.beta.-aminoethyl)piperazine are used as cycloaliphatic amines.

19. The process of claim 16, characterized in that diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diisopropyltriamine are used as aliphatic amines.

20. The process of claim 1, characterized in that the auxiliary and additive agents c) optionally to be jointly used are combined with the polyol component b), whereupon the processing by the two-component system ensues.