DE2212390A1 - Curing agents for epoxy resins - produced by condensation of polyamines with aldehydes or ketones,and sec phosphites - Google Patents

Abstract

Title cpds. are of formula: (in which R1 and R2 are each alkyl, aryl, alkaryl, alkoxyalkyl, hydroxyalkoxyalkyl, alicyclic gp. alian alkylene - or alkylenoxy alkylene ring; R3 is H or alkyl; R4 is an alicycclene-, arylene-, alkarylene- or aralkylene gp., or -CH2CH2-(NH-CH2CH2)x - NH2 gp.) or Advantages include reduced inflammability, improved light stability and increased metal-resin adhesion.

Description

INTERSTAB LIMITED, Stockpit Road, Kirkby Industrial Estate, Liverpool L)) 7TH, Great Britain Hardeners for epoxy resins Epoxy resins are defined as substances that contain more than one epoxy group and are capable of being converted into one -suitable thermosetting form converted by treatment with special hardening agents to become. The epoxy group can be either internal, terminal or cyclic Structure are located within the resin, which depends on the manufacturing process. One type of epoxy resin is made by condensing bisphenol A and epichlorohydrin obtain. These compounds have terminal epoxy groups derived from epichlorohydrin. The products thus obtained differ from liquids with lower and high viscosity to brittle solid substances. To turn this into a usable Form, these resins must be treated with suitable hardeners, which cross-link the individual molecules through the terminal epoxy groups and so on form a highly branched, thermosetting polymer, many types of compounds have already been described for these purposes. The main links fall into the following main categories: a) polyamides, b) aliphatic Amines, c) aromatic amines, d 'anhydrides.

These hardeners can either be used alone or in admixture with one another at various concentrations to produce a number of batches can be used, which can be used for numerous areas of application, such as a) surface coatings, b) adhesives, c) in the electrical field, d) floor coverings, e) road surfaces, f) castings, g) casings, h) foams.

The type of resin and hardener chosen varies widely Extent and depends on whether the Temisch for curing at room temperature is needed or whether a degree of post-curing or hardening is provided. Such factors bring many other considerations to a resin composition, what the service life of the mixture and the heat distortion temperature of the finished product Product are relevant. From the different and widely diverging requirements, which are placed on a starting resin, it is easy to see that a large Variety of hardening agents is needed and in fact already available is. An area that is, however, still limited by the present range of hardeners does not seem to be included is the provision of connections with a) lower flammability, b) better light stability, c) better metal-resin adhesion.

The object of the present invention is now to provide a number to create new connections that are called Hardeners for epoxy resins are suitable and offer particular advantages for the aforementioned purposes.

The compounds according to the invention are phosphonates; by Condensation of polyamines with aldehydes or ketones and with secondary phosphites can be obtained.

The polyamines that can be used include ethylene diamine, Diethylenetriamine, triethylenetetsramine, tetraethylene pentamine, pentaethylene hexamine, Isophoronediamine, p-phenylenediamine, m-xylylenediamine and 4; 4'-diaminodiphenylmethane.

Suitable aldehydes and ketones include formaldehyde, paraformaldehyde, Acetaldehyde, benzaldehyde and acetone.

Suitable secondary phosphites are dimethyl, diethyl, dibutyl, Diamyl, dihexyl, diisodecyl bis (2-ethoxyethyl), bis (2-butoxyethyl, bis-dipropylene glycyl) dicyclohexyl, Diphenyl and dibenzyl phosphites, cyclic phosphites, for example ethylene phosphite and ethyleneoxyethylene phosphite, and di-sec. Phosphites with alkyl, aryl, cycloaliphatic and alkoxyalkyl crosslinking groups, for example diethyl-1,6-hexamethylene-di-sec-phosphite, Diethyl-1,10-decamethylene-di-sec-phosphite, diethyl polyethylene glycol-200-di-sec. -phosphite, diethylpolypropyleneglycyl-400-di-sec-phosphite, diethyl 1,4-cyclohexenyl-di-sec-phosphite, Diphenylbisphenol-A-di-sec. -phosphite.

The invention includes compounds which are prepared from ethylene or polyethylene polyamines and which have the general formula: in which R1 and R2 = an alkyl, aryl, alkaryl, alicyclyl, alkoxyalkyl or hydroxyalkoxyalkyl radical or an alkylene or alkyleneoxyalkylene ring, R5 = H or alkyl radical, x = o or an integer.

The invention further comprises compounds of the general formula: in which R1, R2 and R3 have the aforementioned meaning and R4 is an alicyclic, arylene, alkarylene or aralkylene group.

The invention further comprises compounds of the general formula; in which R1, R2 and R5 have the abovementioned meaning and R5 is R4 or -CH2CH2- (NH-CH2CH2) X-.

The invention is illustrated by the following examples.

Examples: 1.) 103.2 g (1 mol) of diethylenetriamine were added in portions 30 g (1 mol) of paraformaldehyde were added with stirring at 30 to 400 ° C. The clear one Reaction mixture were added dropwise 110.0 g (1 mole) dimethyl phosphite added at the same temperature. The homogeneous mixture thus formed became under Vacuum heated to remove volatile components up to a final temperature of 80 ° C at 5 mm.

After clarification by filtering through a filter, it passed Clear yellow 1 obtained essentially from dimethyl diethylenetriaminomethane phosphonate with P: 13.5%, N: 18.8% (calculated P: 13.8%, N: 18.7%) and a refractive index at 20 ° C of 1.4971.

100 g diglycidyl ether of 2,2-bis (4-hydroxyphenyl) propane with a Epoxy value of 0.53 / 100 g resin was mixed with 51 g of the product. The mixture cured at room temperature and formed a solid resin, which subsequently cured at 500 C was post cured in 48 hours and found to be in a average time of 6 seconds to extinguish itself.

2.) A dispersion of) 0 g (1 mol) of paraformaldehyde in chloroform (400 ml) was added dropwise with stirring at 50-350 ° C. 105.2 g (1 mol) of diethylenetriamine added. To the solution, 158.1 g (1 mol) of diethyl phosphite was added dropwise at the added at the same temperature. The reaction mixture was refluxed and the water of reaction collected using a Dean and Stark reverser. The volatiles were removed by heating in vacuo to a final temperature removed from 800 C at 5 mm and the cloudy oil was clarified by filtration. That The pale orange oil obtained consisted essentially of diethyl diethylenetriaminomethane phosphonate with P: 12.7%, N: 17.2% (calculated P: 12,), N) 16.6%) and a refractive index at 200 C of 1.4910.

There were 55 g of the product with 100 g of the epoxy resin according to Example 1 mixed to produce a solid resin, which at an average time of 10 seconds to extinguish itself.

5.) The product according to Example 2 can also be obtained by removing the water of reaction and the solvent are prepared prior to the addition of the phosphite. Additionally to chloroform, benzene or petroleum ether can be used as an azeotropic solvent will. This technical measure can improve the compatibility of the Hardener and epoxy resin can be achieved.

103.2 g (1 mol) of diethylenetriamine in chloroform, benzene or petroleum ether (400 ml), 30 g (1 mol) of paraformaldehyde were added in portions at 40 to 450.degree. After the addition was complete, the reaction mixture was brought to reflux and this is maintained for 1 hour, whereupon the water of reaction is removed azeotropically became. The solvent was heated in vacuo to a final temperature of 800 C at 5 mm away. 138.1 g (1 mole) of diethyl phosphite were added dropwise added at 120 to 1300 C and the temperature was held for 1 hour. After this Filtration through a filter gave a clear, pale orange oil, that essentially consists of diethyl diethylenetriaminomethane phosphonate with P: 12.4%, N: 16.5 % (calculated P: 12.3%, N: 16.6%) and a refractive index at 200 C of 1.4885 duration.

50 g of the product were mixed with 100 g of epoxy resin according to Example 1 Formation of a solid resin mixed by itself in an average time of 5 seconds to extinguish.

4.) A mixture of 146.2 g (1 mol) of triethylenetetramine and 138.1 75 g (1. mol) of diethyl phosphite were added dropwise with stirring at 30 to 400 ° C (1 mol) 40% aqueous formaldehyde added. The reaction mixture was stirred the volatile constituents are removed by heating in vacuo and as in example 1 worked up to essentially diethyltriethylenetetraminomethane phosphonate as yellow Oil with P: 10.1%, N: 18.7% (calculated P: 10.5%, N: 18.9%) and a refractive index at 200 C of 1.5018.

50 g of the product were mixed with 100 g of the epoxy resin according to Example 1-mixed to form a solid resin that will settle in an average time of 9 seconds itself extinguished 5.) 146.2 g (1 mol) of triethylenetetramine in benzene (200 ml) were 44 g (1 mol) of acetaldehyde dissolved in 100 ml of benzene at 50 to 40 ° C added and the mixture heated under reflux. The water of reaction and the solvent was removed from the reaction mixture as in Example 3 There were 138.1 g (1 mol)) of diethyl phosphite dropwise at 100 to. 110 ° C added and the temperature was held for 2 hours. After clarifying by filtering a yellow oil was obtained, consisting essentially of diethyl triethylenetetraminethylidene phosphonate with P: 10.0%, N: 17.9% (calculated P: 10.0%, N: 18.1%) and a refractive index consisted of 1.4850 at 20 ° C.

41 g of the product were mixed with 1.00 g of the epoxy resin according to Example 1 to produce a solid resin that is mixed in an average time of 5 seconds to extinguish itself.

6.) 103.2 g (1 mole) of diethylenetriamine in benzene (300 ml) became 58 g (1 mol) of acetone were added under reflux and this was maintained for 1 hour. The water of reaction and the solvent were from 'the reaction mixture as in Example 5 removed. 138.1 g (1 mol) of diethyl phosphite were added dropwise 600 C added and the temperature maintained for 2 hours. After the clarification by filtration, the almost water-white oil consisted essentially of diethyl diethylenetriaminoisopropylidonophosphonate with P: 10.5%, N: 29.3 ffi (calculated P: 10.6%, N: 29)%) and one Refractive index at 200 C of 1.4705.

There were 48.5 g of the product with 100 g of the epoxy resin according to Example 1 to produce a solid resin mixed in an average time of 6 seconds to extinguish itself.

7.) 146> 2 g (1 mol) of triethylenetetramine in benzene (500 ml) were 106 g (1 mol) of benzaldehyde added under reflux and maintained for 1 hour. The water of reaction and the solvent were removed from the reaction mixture according to Example 5 removed. 138.1 g (1 mole) of diethyl phosphite were added dropwise at 80-900 C added and the temperature maintained for 3 hours. After clarifying through Filtration gave a viscous, orange-colored oil that was essentially from diethyltriethylenetetraminobenzylidene phosphonate with P: 8.2%, N: 15.3% (calculated P: 8.3%, N: 15.1%) and a refractive index at 200 C of 1.5580.

49 g of the product were mixed with 100 g of the epoxy resin according to Example. 1 mixed to produce a solid resin, which in an average time of 16 seconds made itself extinguish.

8.) With 189.5 g (1 mol) of tetraethylene pentamine instead of triethylene tetramine the procedure of Example 1 was repeated to essentially diethyltetraäthylenpen'taminomethanphosphonat as a pale orange oil with P: 9.0, N: 21.1% (calculated P: 9.2, N: 20.6%) and a Obtain refractive index at 200 C of 1.5040.

52 g of the product were mixed with 100 g of epoxy resin according to Example 1 Producing a solid resin mixed that takes an average of 8 seconds to extinguish itself.

9.) The procedure of Example 1 was repeated with 232 g (1 mol) Pentaethylene hexamine as the polyamine and 158.1 g (1 mol) of diethyl phosphite as the secondary Phosphite to diethylpentaäthylenhexaminomethanphosphonat as a red oil with P: 8.2 , N: 21.9% (calculated P: 8, l, N: 22.0%) and a refractive index at 200 C of 1.5069 to get.

48 g of the product were mixed with 100 g of epoxy resin according to Example 1 Making a solid resin mixed that takes an average of time of 9 seconds to extinguish itself.

10.) With 60.1 g (1 mol) of ethylenediamine instead of diethylenetriamine the procedure of Example 2 was repeated and it was essentially diethyl (2-aminoäthylenaminomethan) phosphonate as a pale yellow oil with P: 14.2%, N: 13.8 ß (calculated P: 14.7%, N: 15.5) and a Refractive index obtained at 200 C of 1.4780.

61.5 g of the product were mixed with 100 g of epoxy resin according to Example 1 Formation of a solid resin mixed which settles in an average time of 5.5 Seconds to extinguish itself.

11. through 26.) The reaction procedure used in Example 2 was followed with polyamines and phosphites according to Table 1 instead of diethylenetriamine and Diethyl phosphite repeated, the end conditions in Examples 15 to 26 80 to 10.00 C at 1 mm pressure. The penultimate column of the table relates refers to the number of parts by weight (GT) of the hardener (HM) per 100 parts by weight (100 GT) epoxy resin (EH) of Example 1.

Table 1 by- Refrak GT-HM cut. Weight Weight% P% N% P% N At- sec. Color of the tion- per self- in g polyamine in g game phosphite product index found calculated 100 GT deletion (1 mole) (1 mole) at 20 ° C EH time in sec. 11 Dibutyl 194.1 D.Ä.TA 103.2 yellow 1.4690 9.5 13.4 9.8 13.3 62 8 12 dibutyl 194.1 T.Ä.TA 146.2 yellow 1.4760 9.0 15.2 8.8 15.9 58 8 13 Dibutyl 194.1 T.Ä.PA 189.3 pale orange 1.4850 7.9 17.5 7.9 17.7 52 9 14 Dibutyl 194.1 P.Ä.HA 232.0 orange red 1.4892 7.2 17.8 7.1 19.0 48 9 15 Diamyl 222.2 D.Ä.TA 103.2 pale yellow 1.4740 9.2 12.3 9.2 12.4 64 5 16 Diamyl 222.2 T.Ä.TA 146.2 yellow 1.4844 8.4 15.0 8.2 14.7 60 8.5 17 Diamyl 222.2 T.Ä.PA 189.3 orange 1.4920 7.8 16.1 7.3 16.5 54 8 18 Diamyl 222.2 P.Ä.HA 232.0 orange-red 1.4956 6.1 17.0 6.7 18.0 51 5 19 Dihexyl 250.4 D.Ä.TA 103.2 pale yellow 1.4659 8.8 11.1 8.5 11.5 48 9 20 dihexyl 250.4 T.Ä.TA 146.2 yellow 1.4865 7.7 14.1 7.6 13.7 65 13 21 dihexyl 250.4 T.Ä.PA 189.3 orange 1.4891 6.4 15.1 6.9 15.5 64 14 22 dihexyl 250.4 P.Ä.HA 232.0 orange-red 1.4895 6.6 17.0 6.3 17.0 59 18 23 Diiso- 362.5 D.Ä.TA 103.2 pale yellow 1.4710 6.0 8.4 6.5 8.8 84 10 decyl 24 bis (2- 282.4 D.Ä.TA 103.2 yellow 1.4790 7.6 10.6 7.8 10.6 69 13 butoxy ethyl) 25 Dibenzyl 262.0 D.Ä.TA 103.2 red 1.5582 7.9 11.5 8.2 11.3 66 11 26 Ethylene 152.1 D.Ä.TA 103.2 orange red 1.5070 12.0 15.9 11.6 15.8 47 5 oxyäthy- len (DEG) 27. to 30.) For these examples, the reaction process according to Example 1 was used; the data are given in Table 2.

Table 2 by- Refrak GT-HM cut. Weight Weight% P% N% P% N At- sec. Color of the tion- per self- in g polyamine in g game Phosphite Product Index found calculated 100 GT deletion- (1 mole) (1 mole) at 20 ° C EH time in sec. 27 Bis (2- 226.2 D.Ä.TA 103.2 pale yellow 1.4872 9.5 12.5 9.1 12.3 45 8.5 ethoxy ethyl) 28 bis (2- 226.2 T.Ä.TA 146.2 orange-yellow 1.4949 8.5 14.8 8.1 14.6 50 7 ethoxy ethyl) 29 bis (2- 226.2 T.Ä.PA 189.3 orange 1.5015 7.6 16.8 7.2 16.4 50 8 ethoxy ethyl) 30 bis (2- 226.2 P.Ä.HA 232.0 orange-red 1.5020 6.4 17.3 6.6 17.9 40 8.5 ethoxy ethyl) 31. to 37.) The reaction process according to Example 6 was used, with acetone being used as the carbonyl compound and a reaction time of 2 to 4 hours for the phosphite for these examples. The data are shown in Table 3.

Table 3 by- Refrak GT-HM cut. Weight Weight% P% N% P% N At- sec. Color of the tion- per self- in g polyamine in g game phosphite product index found calculated 100 GT deletion (1 mole) (1 mole) at 20 ° C EH time in sec. 31 Diethyl 138.1 T.Ä.TA 146.2 pale yellow 1.4941 9.4 17.0 9.6 17.3 45 8 32 Diethyl 138.1 T.Ä.PA 189.3 yellow 1.5018 8.2 19.0 8.4 19.1 45 10 33 Diethyl 138.1 P.Ä.HA 232.0 Orange 1.4915 7.2 20.2 7.5 20.5 40 8.5 34 Bis (di- 314.3 T.Ä.TA 146.2 yellow 1.4868 6.4 11.0 6.2 11.2 66 4.5 propylene) glycyl 35 Dicyclo- 246.3 T.Ä.TA 146.2 orange 1.4974 7.1 12.7 7.2 12.9 57 14 hexyl 36 Diphenyl 234.0 T.Ä.TA 146.2 yellow 1.5611 7.5 13.5 7.4 13.3 60 15 37 ethylene 108.0 T.Ä.TA 146.2 red-brown 1.5150 11.8 19.4 11.6 19.1 39 6 38.) The procedure of Example 6 was followed to prepare the intermediate product from the reaction of 146.2 g (1 mol) of triethylenetetramine and 58 g (1 mol) of acetone. There were 337.4 g (0.5 mol) of diethyl-1,6-hexamethylene disec.

Phosphite added dropwise at 70 to 800 C and the temperature was held for 4 hours. After clarification by filtration, it became a yellow oil obtained, which consists essentially of 1,6-hexylene-di- (äthyltriethylenetetraminoisopropylidenphosphonat) with P: 9.0%, N: 16.9% (calculated P: 9w2% N: 16.6 «) and a refractive index of 1.4977 at 200 ° C.

44 g of the product were mixed with 100 g of the epoxy resin according to Example 1 mixed to produce a solid resin that is mixed in an average time of 8.5 seconds to extinguish itself.

39-43) The reaction procedure of Example 58 was followed and the experimental data therefor are given in Table 4, wherein triethylenetetramine (1 mole) is used as the polyamine and acetone as the carbonyl compound in each case became.

Table 4 by- Refrak GT-HM cut. Weight Weight% P% N% P% N At- sec. Color of the tion- per self- Di-sec. Phosphite in g game phosphite product index found calculated 100 GT deletion (0.5 moles) at 20 ° C time in sec. 39 Diethyldecamethylene 179.1 pale orange 1.4943 8.4 15.6 8.5 15.3 48 22 40 diethyl polyethylene 192 yellow 1.4926 8.2 14.5 8.2 14.9 50 3.5 glycyl 200 41 Diethyl polypropylene 292 orange yellow 1.4748 6.2 11.8 6.5 11.9 62 40.4 glycyl 400 42 Diethyl 1,4-cyclohexenyl 150 orange 1.4988 9.0 16.8 9.2 16.7 44 10.0 43 Diphenylbisphenol A 254 orange resinous 7.0 12.3 7.0 12.7 58 35.0 44.) 156 g (1 mol) of isophoronediamine in benzene (300 ml) were added 58 g (1 mol) of acetone under reflux and this was maintained for 1 hour. The water of reaction and the solvent were removed from the reaction mixture as in Example 5. 138.1 g (1 mol) of diethyl phosphite were added dropwise at 1000 ° C. and the temperature was maintained at 90 to 950 ° C. for 2 hours. After clarification by filtration, a clear, pale yellow oil was obtained, consisting essentially of diethyl isophoronediaminoisopropylidene phosphonate with P: 9.4 $, N: 8.2 β (calculated P: 9.3%, N: 8.4) and a refractive index consisted of 1.4756 at 200 C.

88 g of the product were mixed with 100 g of the epoxy resin according to Example 1 mixed to produce a solid resin that is mixed in an average time of 5 seconds to extinguish itself.

45.) 136 g (1 mol) of m-xylylenediamine in benzene (300 ml) became 58 g (1 MoL1 of acetone added under reflux and this is maintained for 1 hour Water of reaction and the solvent were removed from the reaction mixture as in Example 3 removed. 158.1 g (1 mol) of diethyl phosphite were added dropwise at 1000.degree and the temperature was held at 90 to 1000 C for 30 minutes. After the clarification filtration gave a clear yellow oil consisting essentially of diethyl m-xylylenediaminoisopropylidene phosphonate with P: 9.7%, N: 9.0% (calculated p: 9.9%, N: 8.9%) and a refractive index at 200 C of 1.5129.

83 g of the product were mixed with 100 g of the epoxy resin according to Example 1 mixed to make a solid resin that was non-flammable.

46.) 158.1 g (1 mol) 4,4'-diaminodiphenylmethane in benzene (300 ml) 58 g (1 mol) of acetone were added under reflux and this was maintained for 1 hour. The water of reaction and the solvent were removed from the reaction mixture removed as in example 3. 138.1 g (1 mole) of diethyl phosphite were added dropwise added at 100 to 1200 C and the temperature held at 100 to 1200 C for 2 hours.

After filtering, a viscous, dark brown oil was obtained, that consists essentially of diethyl 41-aminophenylenemethylene-4-phenyleniminoisopropylidene phosphonate with P: 8.0%, N: 7.6% (calculated P: 8.2%, N: 7.4%) and one. Refractive index at 20 ° C of 1.5870.

99 g of the product were mixed with 100 g of the epoxy resin according to Example 1 to produce a solid resin that is mixed by itself in an average time of 2 seconds to extinguish.

47.) 108.1 g of p-phenylenediamine in benzene (300 ml) were 58 g (1 mol) Acetone was added under reflux, which was maintained for 1 hour. The water of reaction and the solvent was removed from the reaction mixture as in Example 3. 138.1 g (1 mole) of diethyl phosphite were added dropwise at 100 to 110 ° C and the temperature was kept at 100 to 110 ° C for 5 hours. The dark brown reaction product was almost solid and consisted essentially of diethyl 4-aminophenyleneiminoisopropylidene phosphonate with P: 10s9%, N: 9.5% (calculated P: 10.8%> N: 9.8%).

75.5 g of the product was melted and mixed with 100 g of the epoxy resin mixed according to Example 1 to produce a solid mass, which in an average time of 6.4 seconds made itself extinguish.

48.) The superior metal adhesion of the epoxy resin used with the new Phosphorus-containing hardeners was hardened over those that were cured with conventional hardeners were processed by the "Latterschitt-Grid-Test according to the standard test method DIN 53151 demonstrated. It was due to ambient temperature hardened Films with a thickness of 50 µm are used, as a film carrier roughened, tinned steel foils with a thickness of 0.1 mm were used.

The products of Examples 31 and 33 were ethylenetriamine with pi compared (11 parts by weight of hardener per 100 parts by weight of epoxy resin were used), the from Shell under the trade name "Epikote 828" Epoxy resin was used in place of the epoxy resins.

The GT values were: Example 51 @ 1-2, Example 55 1-2, diethylenetriamine 2 - 5.

Claims (5)

P a t e n t a n s p r ü c h e 1.) Organic phosphonates, characterized by condensation products of polyamines with aldehydes or ketones and secondary phosphites. 2.) Compounds according to claim 1, characterized by the general formula: in which R1 and R2 represent an alkyl, aryl, alkaryl, alicyclyl, alkoxyalkyl or hydroxyalkoxyalkyl radical or an alkylene or alky-1-enoxyalkylene ring, hydrogen or an alkyl group and x represents 0 or an integer. 3.) Compounds according to claim 1, characterized by the general formula: in which R1 and R2 represent an alkyl, aryl, alkaryl, alicyclyl, alkoxyalkyl or hydroxyalkoxyalkyl radical or an alkylene or alkyleneoxyalkylene ring, R5 represents hydrogen or an alkyl group and R4 represents an alicyclic, arylene, alkarylene or aralkylene radical. 4.) Compounds according to claim 1, characterized by the general formula: in which R1 and R2 are an alkyl, aryl, alkaryl, alicyclyl, alkoxyalkyl or hydroxyalkoxyalkyl radical or an alkylene or alkyleneoxyalkylene ring, hydrogen or an alkyl group, R5 is an alicyclic arylene, alkarylene, aralkylene radical or the Radical -CH2CH2- (NH-CH2CH2) x- and 7 represent O or an integer. 5.) Epoxy resin compositions, thereby gekennzei @ hnet, as they are with Hardened with the aid of a compound according to any one of claims 1 to 4 as a hardening agent will be.