CH637685A5 - Process for preparing curable adhesives and sealants - Google Patents

Description

The invention relates to methods for producing curable adhesives and sealants and to their use for bonding surfaces or sealing gaps between surfaces.

Anaerobically curable resins with advantageous properties are known to be produced as reaction products of polyisocyanates and acrylic acid esters which have an active hydrogen atom in the non-acrylate part of the ester molecule. Such resins are described in U.S. Patent 3,425,988. This patent relates in particular to a monofunctional starting material with terminal acrylate groups, which is reacted with a polyisocyanate in proportions such that all isocyanate groups are converted into urethane or ureide groups. The acrylic acid esters are preferably acrylic acid and methacrylic acid esters which have functional hydroxy or amino groups in the non-acrylic part of their molecule.

It is also known that polyalkylene ether glycols can be reacted with isocyanates to form urethane prepolymers which are then reacted with molecules containing active hydrogen, e.g. with alcohols, amines, water or other crosslinking agents. These funds are two-part funds, i.e. the alcohol or the amine must be kept separate from the prepolymer until the time of use, since the mixture of the two parts has only a very limited shelf life. As expected, mixing these viscous liquids creates difficulties with unevenness and incomplete curing. Similar polyurethane coatings are also known which cure under the influence of moisture; however, these suffer from the disadvantage that the hardening begins as soon as the coating is spread on the carrier, which impairs the control of the coating process.

The object of the invention was to provide processes for the preparation of curable adhesives and sealants which, even as one-piece adhesives and sealants, have long durability and more controllable curability, these synthetic resins also having improved physical properties, such as excellent tensile strength, among other things. and impact resistance, good flexibility even at low temperatures and excellent hardening capacity over large gaps, e.g. 1 to 1.25 mm, should have.

This object is achieved according to the invention in the un637 685

dependent patent claims 1 and 2 characterized method for the production of curable adhesives and sealants and solved by their use in the independent claims 23 and 31.

5 Advantageous embodiments of the invention are shown in the dependent claims.

The invention is explained in more detail below with the aid of examples.

The monomer produced according to the invention can be understood as m one-component polymerizable block copolymer (prepolymer) with well-defined rigid and flexible segments. This is achieved by chemically binding two "prepolymers" which act as precursors and which are then "capped" with functional acrylate groups or 15 methacrylate groups. According to a preferred embodiment, a "flexible" polymeric methylene ether diol segment of relatively low molecular weight with an isocyanate equivalent of a rigid "diisocyanate" such as tolylene diisocyanate or methylene diisocyanate (di-phenylmethane-4,4'-diisocyanate) with respect to its hydroxyl equivalent is used, implemented to form urethane bonds. Before the reaction with the polyalkylene ether diol, the diisocyanate is preferably reacted in excess with another rigid radical which has at least two reactive hydrogen atoms in hydroxyl-25 or non-tertiary amino groups, as a result of which the other rigid radical with 0 = C = N groups is blocked. “Rigid” segments are those which contain aromatic or cycloaliphatic rings. If several segments are involved, they should be connected to one another either in the form of condensed rings or by the smallest possible number of carbon atoms (e.g. in the case of linear links 1 to 2, in the case of branched links 1 to 8 carbon atoms) or Heteroatoms bound so that there can be no 35 or only a slight bending of the segments. “Flexible” segments are segments that contain predominantly linear aliphatic ether residues. Functional side groups including aromatic, heterocyclic and cycloaliphatic groups and chain branches can also be introduced, provided that this does not significantly impair the required flexible nature of the linear part and does not lead to a deterioration in the properties of the cured resins.

Examples of polyisocyanates that can be used to prepare the new 45 monomers include phenyl diisocyanate, tolylene diisocyanate, diphenyl-4,4'-diisocyanate, diphenylmethane-4,4'-diisocyanate, dianisidine diisocyanate, naphthylene-l, 5- diisocyanate, diphenyl ether 4,4'-diisocyanate, p-phenylene diisocyanate, dicyclohexyl methane 4,4'-diisocyanate, so 1,3-bis (isocyanatomethyl) cyclohexane, cyclohexylene diisocyanate, tetrachlorophenylene diisocyanate, 2,6-diethyl p-phenylene diisocyanate and 3,5-diethyl-4,4'-diisocyanatodiphenylmethane. Other polyisocyanates which can be used are the rigid, higher molecular weight polyisocyanates obtained by reaction of polyamines containing terminal primary and secondary amino groups or of polyhydric alcohols, e.g. Alkane, cycloalkane, alkene or cycloalkene polyols, such as glycerol, ethylene glycol, bisphenol-A, bisphenol-A substituted by 4,4'-dihydroxyphenyldimethylmethane and the like-60, obtained with an excess of one or more of the isocyanates described above will. These higher molecular weight urethane or ureide polyisocyanates correspond to the general formula

H °

I II

[0 = C = N-RI-N-C — X] nB in which R1 is a substituted or unsubstituted alkyl, Al-

637 685

kenyl, cycloalkyl, cycloalkenyl, aryl, aralkyl or alkaryl radical having 2 to about 20 carbon atoms, X is R2 I

Meaning -O- or -N-, where R2 is hydrogen or a lower alkyl radical having 1 to 7 carbon atoms, B is a polyvalent organic radical from the group of substituted and unsubstituted cycloalkyl, cycloalkenyl, aryl, aralkyl, alkaryl and means heterocyclic radicals and n is an integer from 2 to 6.

The diisocyanate is preferably reacted with another rigid segment in the form of an aromatic or cycloaliphatic compound which has at least two reactive hydrogen atoms, preferably with diamines and in particular with diols. Suitable compounds are 2,2- (4,4'-dihydroxydiphenyl) propane (ie bisphenol-A), 4,4'-iso-propylidenedicyclohexanol (ie hydrogenated bisphenol-A), ether-oxylated bisphenol-A, propoxylated bisphenol- A, 2,2- (4,4'-dihydroxydiphenyl) butane, 3,3- (4,4'-dihydroxydiphenyl) pentane, et, a '- (4,4'-dihydroxydiphenyl) -p- diisopropylbenzene, cyclohexanediol (1,3), cyclohexanediol (1,4), cyclohexanedimethanol (1,4), bicyclic and tricyclic diols, such as 4,8-bis (hydroxymethyl) tricyclo- [5.2.1.02'6] -decane, 2,2,4,4-tetramethyl-cyclobutanedioI- (1,3), hydroquinone, resorcinol, 2,2- (4,4'-dihydroxydiphenyl) sulfone and 4 , 4'-oxydiphenol and halogenated derivatives thereof, such as tetrabrominated ethoxylated bisphenol-A. These ring compounds can also be substituted by reactive or non-reactive groups, such as alkyl groups having 1 to 4 carbon atoms. Depending on the reactants, this reaction can be carried out at temperatures from room temperature to 180 ° C., preferably from 40 to 120 ° C. At the lower temperatures, the use of conventional catalysts is recommended. If necessary, non-reactive diluents can also be added.

The organic polyisocyanate, optionally reacted as described above, is reacted with a polymeric alkylene ether compound which bears a functional group at each chain end which has a reactive hydrogen atom in a hydroxyl group.

The polyalkylene ether compounds or copolyalkylene ether compounds used according to the invention have the general formula

HQ

-fCH,

> x °>

)

Rr - (CK-

y r4

-CH-O -) -

"xl n

in which x is an integer from 1 to 8, y is an integer from 0 to 20, z is an integer from 0 to 10 and n is an integer from 1 to 100. X preferably has a value of 2 to 6, y a value of 1 to 5, z a value of 0 to 2 and n a value of 3 to 60. In particular, x has a value of 4 to 6, y the value 1 or 2 , z has the value 0 or 1 and n has a value of 5 to 40. R3 and R4 can be hydrogen atoms, lower alkyl radicals with 1 to 3 carbon atoms, cycloaliphatic radicals, cycloalkenyl radicals or aromatic radicals with up to 8 carbon atoms or heterocyclic radicals with up to 8 carbon and / or heteroatoms. It is also very advantageous if the glycol has a linear structure in order to give the segment a high degree of flexibility. Suitable linear polyols are polytetramethylene ether glycols and polyethylene ether glycol. Representative branched chain polyols are poly-1,2-propylene ether polyol and poly-1,2- or -1,3-butylene

ether glycol. The production and properties of polyols of this type are described in the literature, e.g. in the work "Polyurethanes -Chemistry and Technology" by J.H. Saunders and K.C. Frisch, publisher Interscience, New York, 1963.

5 The flexible polyalkylene ether, which has active hydrogen-containing functional groups, is reacted with the polyisocyanate in proportions such that the polyisocyanate is present in excess in relation to the concentration of the groups containing the active hydrogen. In this way, a product is obtained which has an O = C = N group at both ends of the polyalkylene ether segment. The molar excess of polyisocyanate can vary in the range from about 0.05 to 6.

This reaction can be carried out at temperatures from room temperature to 150 ° C., preferably from 40 to 120 ° C. After addition of the flexible diol, 0.1 to 30 hours are required in the preferred temperature range until the reaction has ended. The reaction can optionally also be catalyzed, and non-reactive solvents can be used for viscosity control 20.

The product of the above reaction is reacted with acrylic acid or methacrylic acid ester, which has a hydroxy or a non-tertiary amine group in the molecule, in the quantitative ratio of at least one mole of ester to an isocyanate equivalent 25 (based on the 0 = C = N group content). This leads to the formation of a monomer or, more precisely, prepolymer for an adhesive or sealing synthetic resin which is capped at both chain ends with functional acrylate or methacrylic groups. Esters corresponding to the general formula are suitable for the purposes of the invention

RsO I II

h2c = c-c-o-r6-x-h,

35

in which x has the meaning given above, R5 is hydrogen, chlorine, methyl or ethyl and R6 is a lower alkylene radical having 1 to 8 carbon atoms, the phenylene or the naphthylene radical.

40 Examples of such hydroxyl or amino group-containing esters are acrylic acid hydroxyethyl ester, methacrylic acid hydroxyethyl ester, methacrylic acid amino ester, methacrylic acid 3-hydroxypropyl ester, methacrylic acid aminopropyl ester, acrylic acid hydroxyhexyl ester, methacrylic acid tert.butyiami-45 noethyl ester. The monoacrylic acid esters or monomethacrylic acid esters of bisphenol-A and bisphenol-B and of their fully hydrogenated derivatives, of cyclohexyldiol and the like are also suitable.

The reaction can be carried out in the presence or absence of diluents. Hydrocarbons such as aliphatic, cycloaliphatic and aromatic hydrocarbons, e.g. Benzene, toluene, cyclohexane, hexane, heptane and the like; 55 but it is also advantageous to use other diluents, such as methyl isobutyl cetone, diamyl ketone, methyl methacrylate, isobutyl methacrylate, lauryl methacrylate, isobornyl methacrylate or cyclohexyl methacrylate, especially when it comes to complete compatibility with the sealant. Mixtures of diluents can also be used.

This reaction can also be carried out within a wide temperature range. If the ingredients are used in approximately chemically equivalent amounts, 65 one can at temperatures of room temperature or below, e.g. 10 to 15 ° C, up to and including working at temperatures from 100 to 180 ° C. When the simpler isocyanate adducts are reacted, the ingredients are preferably at

or near room temperature, e.g. at temperatures of 20 to 30 ° C, reacted. At the lower temperatures, the use of a catalyst is recommended. When higher molecular weight isocyanate adducts are reacted, higher temperatures, e.g. from about 40 to 150 ° C, preferred.

The finished monomeric prepolymers produced according to the invention correspond to the general formula

RsO

I II

I CH2 = C-C-0-R6 * I * Dd * Ij * lz Z,

in which R5 and R6 have the above meanings, I a poly-isocyanate radical, D an aromatic or cycloaliphatic polyol or polyamine radical, preferably a diol and in particular a diol of a cycloaliphatic compound, Z a polymeric or copolymeric alkylene ether polyol radical as defined above, z denotes an integer that corresponds to the valence of Z, d has the value 1 or 0 and i, if d = 0, also has the value 0, but otherwise means a number less than the number of reactive hydrogen atoms of D. The asterisk (*) indicates a urethane bond (-NH-COO-) or an ureide bond (-NH-CO-NH-).

The prepolymer described above cures under the influence of free radicals to form a hard, tough resin, for which known peroxy initiators can be used. Examples of such initiators are diacyl peroxides such as benzoyl peroxide, dialkyl peroxides such as ditert.butyl peroxide, ketone peroxides such as' methyl ethyl ketone peroxide, and easily hydrolyzing peresters such as tert.butyl peracetate, tert.butyl perbenzoate, ditert.butyldi-perphthalate, etc. A particularly suitable class of peritiators are the organic hydroperoxides, such as cumene hydroperoxide, methyl ethyl ketone hydroperoxide, tert-butyl hydroperoxide, etc. Of these, cumene hydroperoxide is particularly preferred. The initiators should be used in concentrations of 0.01 to 10 percent by weight, preferably 0.1 to 5 percent by weight, based on the total amount of the agent. Another suitable class of initiators are the compounds containing carbonyl groups which form free radicals under the influence of ultraviolet radiation, such as acetophenon, benzophenone and the benzoin ethers. Suitable UV initiators are described in the U.S. patent application Serial No. 356,679 of May 2, 1973. Mixtures of different initiators can also be used.

The curable synthetic resins produced according to the invention can also be used as two-component adhesives and sealants. In this case, the initiator or one of several initiators can form the second component, which is only mixed with the first component, the monomer, at the point of use. So you can apply the monomer on one of the surfaces to be joined together and the initiator on the other surface and then join the two surfaces together. Likewise, one of the accelerators mentioned below can be applied separately as a second part to one of the surfaces to be joined.

It may be appropriate to carry out the curing polymerization by moderate heat, e.g. Accelerate temperatures from 50 to 150 ° C. At temperatures above about 125 ° C, curing will usually be complete in about 10 minutes or less.

The prepolymers produced according to the invention can be processed into adhesives and sealants which cure anaerobically at room temperature. Compositions of this type, in which hydroperoxides are used as initiators, are described in US Pat. No. 3,043,820. Such anaerobic agents can advantageously accelerate polymerization 637 685

ger, such as organic imides (e.g. benzenesulfimide) and primary, secondary or tertiary amines, as well as inhibitors or stabilizers from the group of olinones or hydroquinones. The accelerators are generally used in concentrations of less than 10 percent by weight, the inhibitors in concentrations of about 10 to 1000 ppm. As an anaerobic adhesive and sealant, these agents have the advantage of a long shelf life and the ability to function at room temperature after the exclusion of oxygen, e.g. harden between the io threads of nuts and bolts or between the adjacent surfaces of the bearing and shaft. The anaerobic curing can be done by moderate heat, e.g. at temperatures up to about 150 ° C, are accelerated.

15 The adhesives and sealants can optionally be made with reactive diluents capable of copolymerizing with the prepolymers. Typical diluents of this type are acrylic acid and diacrylic acid hydroxyalkyl esters, such as acrylic acid hydroxyethyl 20 ester, acrylic acid hydroxypropyl ester and the corresponding methacrylic acid ester including methacrylic acid cyclohexyl ester, methacrylic acid methyl ester, methacrylic acid isobornyl ester, methacrylate methacrylate methacrylate, methacrylate methacrylate, methacrylate methacrylate, methacrylate methacrylate, methacrylate methacrylate, methacrylate methacrylate, methacrylate methacrylate, methacrylate methacrylate, methacrylate methacrylate and methacrylate methacrylate, methacrylate methacrylate, methacrylate methacrylate, methyl acrylate, methacrylate methacrylate, methacrylate methacrylate, methyl acrylate, methacrylate methacrylate, methacrylate methacrylate, methacrylate methacrylate and methyl acrylate, tri. Other unsaturated, reactive thinners such as styrene and acrylonitrile can also be used. The concentration of such diluents should be less than about 60 percent by weight, and preferably 40 to 10 percent by weight.

30 One of the significant advantages of the prepolymers produced according to the invention is their exceptional hardening ability over large spaces, e.g. up to about 2.15 mm. This behavior can be promoted by moderate heat input. However, it is preferably favored by the addition of known accelerators for anaerobic adhesives, such as are described in US Pat. No. 3,625,930; in particular, as an accelerator, the serial no. 498 904 from August 20, 1974 use thiourea compounds described. Such accelerators are advantageously sprayed from dilute solution onto one or both of the surfaces to be joined.

example 1

A four-necked reaction flask equipped with a stainless steel stirrer, nitrogen inlet tube, thermometer, cooler and inlet opening is flushed with nitrogen, heated to about 65 ° C. and with 76.5 g of methylene bis-phenyl isocyanate (MDI) and a solution of 43.0 g of triethylene glycol dimethacrylate (TRIEGMA) and 200 ppm of a quinone as a stabilizing agent. The mixture is heated to 60 to 65 ° C. and in the course of 2 to 3 hours with 95.5 g of polytetramethylene ether glycol of molecular weight 625 (PTME) (“Polymeg 650” from the Quaker Oats Company, Chicago, Illinois; hydroxyl number 179 , 9) offset. The temperature is maintained in the range of 60 to 55 70 ° C.

In order to keep the reaction medium liquid, a dilution solution of 20.0 g of TRIEGMA and 200 ppm of a quinone is gradually added as a stabilizing agent. A sample for 60 NCO analysis is taken 11/2 hours after the addition of glycol has ended. The theoretical NCO content of the MDI-capped polytetramethylene ether glycol (abbreviated MDI * [Polymeg 650] * MDI) dissolved in the specified amount of diluent is 5.39% (level "A"), (urethane binds in these examples through the star -65 gen). Titration with dibutylamine gives a titer of 5.23%. After the sample has been removed for NCO analysis, 61.5 g of 96 percent methacrylic acid hydroxy are added to the reaction mixture in the course of 10 minutes.

637 685 6

propyl ester (HPMA). The mixture is heated for a further 2 hours and held. The temperature of the reaction solution is raised to 60 to 70 ° C. in the course of 1/2 hours. The solution thus obtained contained 62.1 g of the polytetramethylene described in Example 1

holds a concentration of 72% urethane dimethacrylate ether glycol ("Polymeg 650"). The reaction solution structures of the general formula (HPMA * MDI) 2 * [PTME- is kept at 60 to 65 ° C and the heating and stirring

650]. 5 continued an hour after the addition of glycol had ended. The reaction mixture consists of with TDI * HBPA * TDI

Example 2 capped «Polymeg 650» prepolymers (abbreviated

A reaction flask equipped according to Example 1 is (TDI * HBPA * TDI) 2 * [PTME-650]), dissolved in TRIEGMA. It is flushed with nitrogen, heated to 75 ° C., with 50.0 g of MDI and a solution of 43.3 g of 96 percent methacrylic acid

then with a solution of 35.0 g TRIEGMA and 200 ppm io hydroxypropyl ester, 1.8 g TRIEGMA and 100 ppm of a Chi

a quinone as a stabilizer. The mixture is nons as a stabilizing agent and keeps the reaction solution heated to 70 to 75 ° C and in the course of 3 to 3V2 hours IV2 hours to 65 to 70 ° C. The solution thus obtained contains, with 96.2 g of a polytétramethylene ether preheated to 60 ° C. in a concentration of 72% urethane dimethacrylate structure.

glycol with a molecular weight of 960 (“Polymeg 1000” of quarters of the general formula (HPMA * TDI * HBPA * TDI) 2

Ker Oats Company; Hydroxyl number 116.6) was added. You hold the 15 [PTME-650],

Temperature to 65 to 75 ° C and heated after completion of the

Glycol add another hour. To the reaction medium Example 5

To keep liquid, gradually becomes a dilution solution of a reaction flask equipped according to example 1

15.8 g of TRIEGMA and 200 ppm of a quinone as a stabilizing agent were flushed with nitrogen and charged with 69.6 g of TDI. The TDI

added medium. Half an hour after completion of the Gly-20 is heated to 95 ° C. You set slowly over 1 'A

a sample is taken for the NCO analysis, 36 g of HBPA are added to hours. 15 minutes after the addition of which it is determined that the HBPA is desired, a temperature of 50 ° C. is set in the course of 10 minutes.

MDI * [PTME-1000] * MDI prepolymers. The theoretically heated solution of 45.0 g TRIEGMA and 150 ppm of a Chi

The percentage of NCO groups for the prepolymer (only added as a stabilizing agent. As soon as the reaction temperature

finally solvent) is 4.19%; the titration gives 25 temperature 95 ° C, 12.0 g HBPA is placed in 4 to 6 portions

a titer of 4.21%. It is added in the course of 10 minutes. 15 minutes after the HBPA supplements are finished

42.6 g of 96 percent methacrylic acid hydroxypropyl ester reduced to the bath temperature so that the reaction temperature

and then heats to 65 to 75 ° C for another IV2 hours. The door drops to 60 to 65 ° C. The reaction solution is left in the

The solution obtained contains 96.2 g of polytetramethylene ether glycol than-dimethacrylate structures of the general formula 30 (“Polymeg 1000”) in a concentration of 72% urefe for 2 hours. Then continue to heat

(HPMA * MDI) 2 * [PTME-1000], stirring to 64 to 69 ° C. Half an hour after the end of the glycol addition, a sample is taken for the NCO analysis.

Take example 3. This gives a reaction solution for the reaction solution.

A reaction vessel equipped according to Example 1 is filled with 3.35% NCO (theoretical value 3.22%). From this it follows

Flushed with nitrogen, heated to 60 ° C., with 39.2 g of MDI and then 35 that the desired ones, capped by TDI * HBPA * TDI, were capped with a solution of 44.5 g of TRIEGMA and 200 ppm of an ether prepolymer (abbreviated (TDI * HBPA * TDI) 2 * [PTME-

Chinons loaded as a stabilizer. At 60 ° C one sets in 1000]). In order to keep the reaction medium liquid

154.1 g of a preheated to 60 ° C over 3 hours, a dilution solution of 36.4 g of TRIEGMA is used

Polytetramethylene ether glycol of molecular weight 1960 and 150 ppm of a quinone as a stabilizer. In the end

("Polymeg 2000" from the Quaker Oats Company; hydroxyl number 40 is 48.0 g of 96 percent methacrylic acid hydroxypropyl

57.1) to the heated MDI solution. The temperature of the ester is added to the chain ends of the prepolymer

Reaction mixture is kept at 65 to 75 ° C. To be capped according to functional methacrylate groups.

The end of the glycol addition is heated for an hour.

Then a solution of 20.3 g of TRIEGMA is gradually added. The solution thus obtained contains a concentration of and 200 ppm of a quinone as a stabilizing agent in order to keep the reaction medium liquid, the 70-70% urethane dimethacrylate structures of the general formula. Finally, 39.1 g (HPMA * TDI * HBPA * TDI) 2 * [PTME-1000] are used.

96 percent methacrylic acid hydroxypropyl ester and heated for a further 2 hours at 60 to 65 ° C. Example 6 thus obtained

Solution contains urethane in a concentration of 72%. A reaction flask equipped according to Example 1 is flushed with dimethacrylate structures of the general formula 50 nitrogen and charged with 34.8 g TDI. The TDI will

(HPMA * MDI2 * [PTME-2000]. Heated to 100 ° C. Then slowly in the course of

VU hours 18 g HBPA too. 15 minutes after the end of Example 4 of the HBPA, a reaction flask equipped according to Example 1 is flushed with preheated solution of 35.0 g of TRIEGMA and 150 ppm of nitrogen and 69.6 g in the course of 5 minutes Toluene diisocyanate (TDI) 55 quinones added as a stabilizing agent. 15 minutes later, (80% 2,4-isomer and 20% 2,6-isomer) are charged. The TDI was added to the 6.0 g HBPA in 3 to 5 servings. After completion, the mixture is heated to 95 to 100 ° C. Then slowly adding the HBPA additive, the bath temperature is added to 36 g of hydrogenated bisphenol-A (HBPA) for as long as 2 hours. The reaction temperature is set to 60 to 65 ° C. 15 minutes after the HBPA addition has ended. Then, in the course of IV * hours, a solution of 60 g of reaction solution, 98.2 g of poly-tetramethylene ether glycol from Mo-TRIEGMA and 300 ppm of a quinone as a stabilizer is slowly added to the solution over the course of 10 minutes. molecular weight 2000 (“Polymeg 2000”). The mixture is then heated 15 minutes later, 12.0 g of HBPA in 4-6 portions are stirred for one hour at 60 to 70 ° C. To set the reak. 15 minutes after keeping all HBPA (total 48.0 g) of the addition medium liquid, a dilution solution has been set, the bath temperature is reduced so far from 15.2 g of TRIEGMA and 150 ppm of a quinone as a stabilizer that the reaction temperature is 60 to 65 ° C. The detergent added. Then, in the course of 5 minutes, the reaction mixture consists of 27.4 g of 96% methacrylic acid hydroxypropyl ester mixed with tolylene diisocyanate to give capped HBPA prepolymers (abbreviated to TDI * HBPA * TDI), and the mixture is heated at 60 to 65 ° C. for a further hour. So received in TRIEGMA. ne solution contains urethane in a concentration of 72%

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dimethacrylate structures of the general formula (HPMA * TDI * HBPA * TDI) 2 * [PTME-2000].

Example 7

A reaction flask equipped according to Example 1 is flushed with nitrogen and charged with 52.4 g of liquid, hydrogenated MDI (“H12-MDI”, “Hylene W” from E.I. du Pont de Nemours and Company, Wilmington, Delaware). The Hu-MDI is heated to 100 ° C. 10.8 g of cyclohexanedimethanol (CHDM) are added to the diisocyanate in the course of 20 minutes. A dilution solution of 35.0 g of TRIEGMA and 150 ppm of a quinone as stabilizer is then added over the course of 10 minutes. As soon as the temperature reaches 100 ° C, 3.6 g of cyclohexanedimethanol are slowly added. Half an hour later, a sample is taken for NCO analysis. The titration gives a titer of 8.40%, while the theoretical NCO value (including solvent) is 8.10%. It follows from this that the desired H12-MDI * CHDM * H12-MDI prepolymer has formed. The bath temperature is now reduced so far that the temperature of the solution adjusts to 60 to 70 ° C. The reaction solution is mixed with 98.3 g of polytetramethylene ether glycol of molecular weight 2000 in the course of 1 to 2 hours. An hour later, further dilution solution (29.1 g TRIEGMA and 150 ppm stabilizer) is added. Then another sample is taken for the NCO analysis. The titration gives a titer of 3.55% NCO, while the theoretical NCO content is 3.62%. The desired prepolymer was again formed: (H12-MDI * CHDM * H12-MDI) 2 * [PTME-2000]. Then 44.4 g of 96 percent methacrylic acid hydroxypropyl ester are added over the course of 10 minutes, and the mixture is then heated further to 60 to 65.degree. The solution thus obtained contains in a concentration of 70% urethane dimethacrylate structures of the general formula (HPMA * H12-MDI * CHDM * H12-MDI) 2 * [PTME-2000],

Example 8

This example illustrates typical anaerobic adhesives from the prepolymers described above or mixtures thereof. With thorough stirring, 4.6 g of methacrylic acid hydroxypropyl ester are added to 79 g of prepolymer solution (70 to 75% solids). Then a slurry of 0.38 g of saccharin in 3.8 g of triethylene glycol dimethacrylate is stirred in. Then 5.6 g of acrylic acid (as adhesion promoter) and 2.8 g of Cu mol hydroperoxide (CHP) are added and the mixture is stirred for another hour. If desired, stabilizers, accelerators, thickeners, plasticizers and the like can also be added in a manner known per se.

Example 9

Anaerobic adhesives are produced according to Example 8 using the prepolymers according to Examples 1 to 7.

Table I

Prepolymer General structural formula

A (HPMA * MDI) 2 * [PTME-650]

B (HPMA * MDI) 2 * [PTME-1000]

io C (HPMA * MDI) 2 * [PTME-2000]

D (HPMA * TDI * HBPA * TDI) 2 * [PTME-650]

E (HPMA * TDI * HBPA * TDI) 2 * [PTME-1000]

F (HPMA * TDI * HBPA * TDI) 2 * [PTME-2000]

G (HPMA * H12-MDI * CHDM * H12-MDI) 2 *

15 [PTME-2000]

The strength values of these adhesives are given in Table II. The tensile strength is determined according to ASTM test standard 2o D-2095-72 by gluing two steel rods together with their abutting ends. The other two ends of the bars are then pulled apart with a measuring device, such as an Instron tester, and the tensile strength of the bond is measured. The overlap shear 25 tensile strength is determined according to ASTM test standard D-1002-65 by gluing the overlapping surfaces of two steel sheets together. The ends of the samples so assembled are pulled apart with a measuring device such as an Instron tester and the bond shear strength is measured. Compression shear strength, determined according to the U.S. Army Standard MIL-R-46082A (MR), is a measure of the ability of an adhesive to retain a sleeve or bearing on a shaft. In this test, a cylindrical «pin» is glued into the bore of a matching sleeve. The force required to push the pin away from the sleeve is measured using an Instron tester or equivalent. The impact resistance is determined according to ASTM test standard D-950-72 by gluing two matching 40 steel blocks together and then striking one block with the impact of a vibrating pendulum device, such as the Baldwin impact tester. The impact force required to separate the blocks from one another is determined. A temperature of 93 ° C 45 is used in all tests to accelerate curing, in the tensile and compression shear tests for one hour and in the impact test for 1 hour.

Table II prepolymer

Tensile strength- Overlap shear tension- Compression- Impact resistance-

of glue,

strength, kg / cm2 (with

Shear strength,

kg / cm2

Sandblasting unit, kg / cm2

mkg / cm:

inclined. overlapping

Steel sheets)

A

523

308.6

239

0.28

B

382

248.5

187

0.11

C.

253

188

188.4

0.15

D

520

288

376

0.283

E

648

292

297

0.279

F

327

236.5

234

0.219

Example 10

The adhesive based on prepolymer A is examined for its ability to maintain sufficient strength after prolonged exposure to high temperatures. The

65 excellent permanent strength of this adhesive results from Table III. The strength tests are carried out according to the compression shear strength test described above. Samples are taken for the specified number of weeks

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Chen aged at 204 ° C and then divided into two groups, which are examined at room temperature or at 204 ° C.

Table III heat aging duration, weeks

0

3.0 9.5

Compression shear strength, kg / cm2 room temperature 204 ° C

222 121 124

19.3 19.7

Example 11

Another significant advantage of the prepolymers made according to the invention when used for adhesives is their ability to spread over relatively large spaces, e.g. 0.5 mm or more to harden structurally strong bonds with very high impact strength. Table IV explains typical tensile strengths (determined on bonds hardened at room temperature between steel surfaces cleaned with the sandblaster, which had been provided with tetra-u methylthiourea as an activating agent) and impact strengths (determined on workpieces, either using the activator mentioned at room temperature or tool hours) have been hardened at 93 ° C).

Table IV

Prepolymer A C E F G tensile strength, kg / cm2;

Gap 0.5 mm 115.7 84 169 84 Impact resistance, mkg / cm2 Gap 0.5 mm

(with accelerator) 0.287 0.23 0.285 0.336 0.208 gap 0.5 mm

(heat hardened) 0.287 0.26 0.268 0.216 gap 1.4 mm

(heat hardened) 0.137 * 0.24 0.077 * With 6% inorganic thickener to achieve thixotropic behavior.

Example 12

Another decisive advantage of the prepolymers produced according to the invention is their excellent strength at low temperatures. This is explained in Table V, from which it follows that adhesives as described in Example 9 have an extraordinarily high impact strength at low test temperatures even over large gaps. Heat was applied to all samples (93 ° C; 1% hours) to accelerate curing. Then the blocks were cooled to the appropriate temperature and examined immediately; the impact test was carried out as described above.

Table V

Impact resistance, mkg / cm2

room

Prepolymer temperature

0 ° C

-40 ° C - 80 ° C

A 0 mm

0.358

0.429

0.431 0.392

- 0.5 mm

0.287

0.300

0.124 * 0.174

E 0 mm

0.287

0.553

0.508

0.5 mm

0.259

0.246

0.058

F 0 mm

0.219

0.285

0.396 0.401

0.5 mm

0.313

0.324

0.249 0.171

* Heat curing within 45 minutes instead of 90 minutes.

Example 13

A curable agent is prepared from prepolymer A (Table I) by the procedure of Example 8, with the difference that 5% (based on the total weight of the agent) of benzophenone is used in place of the CHP and saccharin. A 0.05 to 0.13 mm thick film of this agent is spread on a glass sheet and irradiated with ultraviolet light. A 400-watt mercury vapor lamp, which is housed in a “Porta-Cure 400” lamp (lamp and lamp manufactured by American Ultraviolet Co.), serves as the UV source. The ultraviolet radiation source is adjusted so that the radiation intensity on the film is 6000 | iW. After exposure for 11 to 13 minutes, the coating has hardened into a hard, dry film. 40 The same means is used to assemble a sample for the lap shear strength test, but using glass strips in place of the steel sheets. The sample is irradiated with 6000 [xW ultraviolet rays at the binding line. The glass strips are fixed in 45 seconds (they can no longer be moved against each other by hand).

Example 14

An adhesive is made from prepolymer E (Table I) 50 according to the procedure of Example 8 with the difference that the CHP and saccharin are replaced by 3 to 5% (based on the total weight of the adhesive) benzoyl peroxide. A 0.05 to 0.13 mm thick film of this adhesive is applied to a steel plate, IV2 hour-55 den hardened in the oven at 93 ° C and then cooled to room temperature. The mass hardens into a dry, permanent film.

As described above, an overlap shear strength test is performed. After curing for 60 hours at 93 ° C, the bond strength is 239 kg / cm2.

C.

Claims (32)

637 685 PATENT CLAIMS 1. A process for the preparation of curable adhesives and sealants, characterized in that one (a) Organic polyisocyanate, the isocyanate groups of which are bonded to aromatic carbon atoms, or organic polyisocyanate, the isocyanate groups of which are bonded to cycloaliphatic carbon atoms, initially with (b) Polyalkylene ether polyol in the ratio of more than one isocyanate equivalent polyisocyanate per hydroxyl equivalent polyalkylene ether polyol and thereafter with (c) converting an alcoholic hydroxyl group in the molecule containing acrylic acid or methacrylic acid ester in the ratio of at least one mole of ester to an isocyanate equivalent of the adduct of (a) and (b). 2. Process for the preparation of curable adhesives and sealants, characterized in that (a) Organic polyisocyanate, the isocyanate groups of which are bonded to aromatic carbon atoms, or organic polyisocyanate, the isocyanate groups of which are bonded to cycloaliphatic carbon atoms, initially with (b) Polyalkylene ether polyol in the ratio of more than one isocyanate equivalent polyisocyanate per hydroxyl equivalent polyalkylene ether polyol and thereafter with (d) converting a non-tertiary amine group in the molecule having acrylic acid or methacrylic acid ester in the ratio of at least one mole of ester to an isocyanate equivalent of the adduct of (a) and (b). 3. The method according to claim 1, characterized in that the reaction product (ai) of aromatic or cycloaliphatic polyol or of a plurality of non-tertiary amine groups containing aromatic or cycloaliphatic polyamine and such an amount of aromatic or cycloaliphatic polyisocyanate as polyisocyanate (a), that one mole of hydroxyl groups of the polyol or one mole of non-tertiary amine groups of the polyamine account for more than one mole of isocyanate groups of the polyisocyanate. 4. The method according to claim 1, characterized in that the polyalkylene ether polyol (b) is polytetramethylene ether glycol. 5. The method according to claim 1, characterized in that as polyisocyanate (a) diphenylmethane-4,4'-diisocyanate or a reaction product (ai) of the type defined in claim 3, for its production as polyisocyanate diphenylmethane-4 , 4'-diisocyanate was used. 6. The method according to claim 1, characterized in that the polyisocyanate (a) is tolylene diisocyanate or a reaction product (a-i) of the type defined in claim 3, for the preparation of which toluene diisocyanate was used as the polyisocyanate. 7. The method according to claim 3, characterized in that the reaction product (a-i) is a reaction product having terminal O = C = N groups of hydrogenated bisphenol A and tolylene diisocyanate. 8. The method according to claim 1, characterized in that there is used as the ester methacrylate or methyl methacrylate. 9. The method according to claim 1, characterized in that one uses an organic solvent in the reactions. 10. The method according to claim 1 or one of claims 3 to 9, characterized in that a curable adhesive and sealant is prepared which contains a solvent which is co-reactive during subsequent curing. 11. The method according to claim 10, characterized in that the co-reactive solvent is iso-methacrylate or cyclohexyl methacrylate. 12. The method according to claim 10, characterized in that the co-reactive solvent is methacrylic acid lauryl ester or methacrylic acid tetrahydrofurfuryl ester. 13. The method according to claim 2, characterized in that the reaction product (a-i) from as polyisocyanate (a) 5 aromatic or cycloaliphatic polyol or of a plurality of non-tertiary amine groups containing aromatic or cycloaliphatic polyamine and such an amount of aromatic or cycloaliphatic polyisocyanate that more than one mole of isocyanate groups per mole of hydroxyl groups of the polyol or one mole of non-tertiary amine groups of the polyamine of the polyisocyanate is eliminated. 14. The method according to claim 2, characterized in that the polyalkylene ether polyol is polytetramethylene ether glycol. 15. The method according to claim 2, characterized in that as polyisocyanate (a) diphenylmethane-4,4'-diiso-cyanate or a reaction product (ai) of the type defined in claim 13, for its preparation as polyisocyanate diphenyl methane 4,4'-diisocyanate was used. 2. 16. The method according to claim 2, characterized in that the polyisocyanate (a) is tolylene diisocyanate or a reaction product (a-i) of the type defined in claim 13, for the preparation of which toluene diisocyanate was used as the polyisocyanate. 17. The method according to claim 13, characterized in that the reaction product (a-i) is a terminal reaction product having 0 = C = N groups and consisting of hydrogenated bisphenol A and tolylene diisocyanate. 18. The method according to claim 2, characterized in that an organic solvent is used in the reactions. 19. The method according to claim 2 or one of claims 13 to 18, characterized in that one produces a curable adhesive and sealant, which a later 35 hardness contains coreactive solvent. 20. The method according to claim 19, characterized in that the co-reactive solvent is iso-methacrylate or cyclohexyl methacrylate. 21. The method according to claim 19, characterized in 40 that the co-reactive solvent methacrylic acid lauryl ester or methacrylic acid tetrahydrofurfurylester is. 22. A curable adhesive and sealant produced by the process according to claim 1. 23. Use of a curable adhesive and sealing means 45 according to claim 22 for bonding surfaces or Sealing gaps between surfaces, characterized in that the agent is brought between the surfaces to be treated and allowed to harden with the aid of a free radical initiator. 50 24. Use according to claim 23, characterized in that the initiator is a peroxy initiator. 25. Use according to claim 23, characterized in that the initiator is activated by ultraviolet rays. 55 bare connection is. 26. Use according to claim 23, characterized in that the adhesive and sealing agent for anaerobic hardening is brought together with a hydroperoxide. 27. Use according to claim 26, characterized in that the hydroperoxide is cumene hydroperoxide. 28. Use according to claim 26 or 27, characterized in that the adhesive and sealing agent is also brought together with a polymerization accelerator. 65 29. Use according to claim 28, characterized in that the accelerator is an imide or an amine. 30. Curable adhesive and sealant, produced by the method according to claim 2. 31. Use of a curable adhesive and sealant according to claim 30 for bonding surfaces or sealing gaps between surfaces, characterized in that the agent is brought between the surfaces to be treated and allowed to harden with the aid of a free radical initiator. 32. Use according to claim 31, characterized in that the initiator is a peroxy initiator. 33. Use according to claim 31, characterized in that the initiator is a compound which can be activated by ultraviolet rays. 34. Use according to claim 31, characterized in that the adhesive and sealing agent for anaerobic hardening is brought together with a hydroperoxide. 35. Use according to claim 34, characterized in that the hydroperoxide is cumene hydroperoxide. 36. Use according to claim 34 or 35, characterized in that the adhesive and sealing agent is also brought together with a polymerization accelerator. 37. Use according to claim 36, characterized in that the accelerator is an imide or an amine.