ADHESIVE METHOD USING TWO-COMPONENT ADHESIVES BASED ON COMPOUNDS HAVING CYCLOTHIOCARBONATE UNITS

Abstract

A bonding process is described in which two substrates are bonded together by applying to the surface of at least one of the substrates a curable, not yet cured 2-component adhesive that comprises, in a first component, a compound A having at least one defined cyclic thiocarbonate unit having a five-membered ring structure and, in a second component, a curing compound B selected from compounds having at least one functional group selected from primary amine groups and secondary amine groups.

Claims

1.-25. (canceled)

26. A bonding process in which two substrates are bonded together by applying to the surface of at least one of the substrates a curable, not yet cured, liquid 2-component adhesive that (a) in a first component comprises at least one compound A having at least one cyclic thiocarbonate unit having a five-membered ring structure in which three members of the five-membered ring have the structure —O—C(═O)—S—, the two remaining members of the five-membered ring being carbon atoms; and (b) in a second component comprises at least one curing compound B selected from compounds having at least one functional group selected from primary amine groups and secondary amine groups, wherein the at least one functional group may also be present in masked, latently reactive form, and wherein the first component, the second component, and/or a further component of the adhesive may optionally comprise at least one compound C that has at least one functional group reactive toward SH groups.

27. The bonding process according to claim 26, wherein the functional group reactive toward SH groups is selected from groups having ethylenically unsaturated bond and epoxy groups and at least two of the compounds A, B, and C are polyfunctional.

28. The bonding process according to claim 26, wherein (a) compound A a number n.sub.A of cyclic thiocarbonate units, n.sub.A being an integer greater than or equal to 1; (b) compound B has a number n.sub.B of functional groups and a number n.sub.C2 of ethylenically unsaturated bonds reactive toward SH groups, n.sub.B being an integer greater than or equal to 1 and n.sub.C2 being an integer greater than or equal to 0; and (c) the first component, the second component and/or a further component optionally comprises at least one compound C that contains a number n.sub.C3 of functional groups reactive toward SH groups, n.sub.C3 being an integer greater than or equal to 1; with the proviso that at least one number out of n.sub.A and the sum of n.sub.B+n.sub.C2 is greater than or equal to 2; and that when n.sub.C2 is zero, then either n.sub.C3 is greater than or equal to 2, or both n.sub.A and n.sub.B are greater than or equal to 2, or both n.sub.A and n.sub.B and n.sub.C3 are greater than or equal to 2.

29. The process according to claim 26, wherein compound A has the formula (I) ##STR00019## where R.sup.1 to R.sup.4 are independently hydrogen or an organic group having up to 50 carbon atoms; alternatively R.sup.2, R.sup.4, and the two carbon atoms of the monothiocarbonate group may together form a five- to ten-membered ring, one of the groups R.sup.1 to R.sup.4 being a linking group to Z, wherein the linking group may also be a chemical bond, n is an integer greater than or equal to 1, and Z is hydrogen or an n-valent organic group.

30. The process according to claim 29, wherein three of the groups R.sup.1 to R.sup.4 in formula I are hydrogen and the remaining group from R.sup.1 to R.sup.4 is the linking group to Z, wherein the linking group may also be a chemical bond.

31. The process according to claim 29, wherein the linking group to Z is a single bond or an ether group —CH.sub.2—O— or an ester group —CH.sub.2—O—C(═O)—.

32. The process according to claim 29, wherein Z is an n-valent organic group having up to carbon atoms, which may contain oxygen atoms, and n is a number from 2 to 5.

33. The process according to claim 26, wherein compound A has the formula (II) ##STR00020## where n is a number greater than or equal to 1, and Z is hydrogen or an n-valent organic group, preferably alkyl, aryl, alkenyl, or aralkyl, in which the group Z may be substituted or unsubstituted and in which the group Z may be interrupted by O, halogen, S, C═O, O—C═O, O—(C═O)— or (C═O)—NR, where R is hydrogen or an organic group.

34. The process according to claim 29, wherein Z is an alkoxylene group or a polyalkoxylene group of the formula G1:
—(V—O—).sub.mV  (G1), where V is a C2 to C20 alkylene group and m is a number greater than or equal to 1.

35. The process according to claim 29, wherein Z is a group of the formula G2: ##STR00021## where W is a divalent organic group having up to 10 carbon atoms and R.sup.10 to R.sup.17 are independently H or a C1 to C4 alkyl group.

36. The process according to claim 26, wherein compound A is selected from the group consisting of compounds of the formula (III) ##STR00022## where n is a number from 1 to 10, and m is a number from 0 to 9; and compounds of the formula (IV) ##STR00023## where n is a number from 1 to 10, and A is a group selected from -Ph-CR.sub.aR.sub.b-Ph- and —(CH.sub.2—CH.sub.2—O).sub.m— CH.sub.2—CH.sub.2—, where R.sub.a and R.sub.b are independently H or C1 to C4 alkyl; and m is a number from 0 to 10.

37. The process according to claim 26, wherein compound B is a compound selected from polyamines having at least two primary or secondary amine groups.

38. The process according to claim 26, wherein compound B is a compound having at least two primary amine groups.

39. The process according to claim 27, wherein the functional groups reactive toward SH groups are selected from ethylenically unsaturated bonds, which are selected from (meth)acrylic, allylic, and vinylic C—C double bonds and C—C triple bonds and from epoxy groups.

40. The process according to claim 26, wherein at least one of the components of the adhesive comprises at least one compound C selected from trimethylolpropane tri(meth)acrylate and alkanediol di(meth)acrylates of C2 to C8 alkanediols.

41. The process according to claim 26, wherein the curing compound B is used in an amount such that the amount n.sub.B of functional groups in curing compound B is from 80 mol % to 120 mol %, based on the amount n.sub.A of cyclic thiocarbonate groups in compound A, and that compound C is used in an amount such that the amount of reactive double bonds n.sub.C3 is from 0 to 120 mol %, based on the amount n.sub.A of cyclic thiocarbonate groups.

42. The process according to claim 26, wherein the two-component adhesive is applied in an applied amount from 0.5 to 1000 g/m.sup.2.

43. The process according to claim 26, wherein the substrates to be bonded are the same or different from one another and are selected from metal, wood, glass, plastic shaped bodies, plastic films, paper, and paperboard.

44. The bonding process according to claim 26, wherein it is a lamination process for producing laminated articles selected from glossy films, composite films, and laminated shaped bodies, wherein a) a first substrate in the form of a first film is provided, b) a second substrate is provided, selected from paper, a second film that may be the same or different from the first film, and shaped bodies, c) a two-component adhesive according to claim 26 is provided, and d) the two-component adhesive is applied onto the first substrate and/or onto the second substrate, optionally being allowed to dry, and the first substrate is laminated onto the second substrate.

45. The bonding process according to claim 26, wherein the adhesive comprises at least one catalyst for catalyzing the reaction of the cyclic carbonate groups in compound A with the functional groups in curing compound B or wherein the adhesive comprises at least one catalyst or initiator for catalyzing or initiating the reaction of SH groups with one another or the reaction of SH groups with ethylenically unsaturated double bonds.

46. The bonding process according to claim 26, wherein bonding takes place at temperatures of less than or equal to 30° C.

47. The use of a curable 2-component composition for bonding in a process according to claim 26, wherein the 2-component composition (a) in a first component comprises at least one compound A having at least one cyclic thiocarbonate unit having a five-membered ring structure in which three members of the five-membered ring have the structure —O—C(═O)—S—, the two remaining members of the five-membered ring being carbon atoms; and (b) in a second component comprises at least one curing compound B selected from compounds having at least one functional group selected from primary amine groups and secondary amine groups, wherein the first component, the second component, and/or a further component of the adhesive may optionally comprise at least one compound C that has at least one functional group reactive toward SH groups.

48. A bonded product produced according to the process according to claim 26.

49. A curable 2-component adhesive composition that (a) in a first component comprises at least one compound A having a molecular weight greater than 1000 g/mol and having at least one cyclic thiocarbonate unit having a five-membered ring structure in which three members of the five-membered ring have the structure —O—C(═O)—S—, the two remaining members of the five-membered ring being carbon atoms; and (b) in a second component comprises at least one curing compound B selected from compounds having at least one functional group selected from primary amine groups and secondary amine groups, wherein the at least one functional group may also be present in masked, latently reactive form; and (c) optionally in the first component, in the second component and/or in a further component comprises at least one compound C that contains at least one functional group reactive toward SH groups, preferably at least one group having an ethylenically unsaturated bond or at least one epoxy group; in the case of compounds having epoxy groups, these are present in the first and/or in the further component of the adhesive; wherein the curing compound B is used in an amount such that the amount n.sub.B of functional groups in curing compound B is from 80 mol % to 120 mol %, based on the amount n.sub.A of cyclic thiocarbonate groups in compound A, and wherein compound C is used in an amount such that the amount of double bonds n.sub.C3 reactive toward SH groups is from 0 to 110 mol %, based on the amount n.sub.A of cyclic thiocarbonate groups; and wherein the adhesive composition in the not yet cured state immediately after the components have been mixed preferably has a zero-shear viscosity at 70° C. of less than 300 Pa s.

50. A curable 2-component adhesive composition according to claim 49, wherein the peel strength after 24 hours of two polyethylene terephthalate films bonded together with an adhesive layer of 3 μm and with a contact pressure of 3 bar is greater than 1.5 N/15 mm.

Description

EXAMPLES

[0213] Measurement of Zero-Shear Viscosity

[0214] The zero-shear viscosity is the threshold value of the viscosity function at infinitely low shear rates. It is measured using an Anton Paar MCR 100 rheometer (US 200 evaluation software) in plate/plate geometry. The samples are measured under oscillatory shear at a low shear amplitude of 10%. Temperature 23° C. (or as stated), angular frequency ramp log 100-0.11/s, measuring gap 0.5 mm, evaluation according to Carreau-Gahleitner I, piston diameter 25 mm.

##STR00018##

Example 1

[0215] 3 g of the compound of structure 1 was mixed with 1.75 g of trimethylolpropane trimethacrylate (LaromerS TMPTMA, BASF), then 1.6 g of polyethyleneimine (LupasolS FG, BASF) was mixed in and the mixture was stirred thoroughly.

[0216] The mixture was applied on stainless steel test specimens and on aluminum test specimens (Rocholl GmbH) and bonded and fixed with an overlap of 2.5 cm×2.5 cm. These were cured overnight at room temperature. After 12 h, the test specimens were bonded handtight. After 48 h, a tensile shear test was carried out at 100 mm/min.

[0217] The measured tensile shear strength on stainless steel was 4.4 MPa, this being 5 MPa after 9 days at room temperature and 6 MPa after 16 days (adhesion failure in all cases).

[0218] The measured tensile shear strength on aluminum was 3 MPa after 48 h, this being 4 MPa after 9 days and after 16 days.

[0219] Application amounts in the tensile shear tests are in each case 0.2 g/(2.54 cm).sup.2.

Example 2

[0220] 2 g of the compound of structure 1 was mixed with 0.6 g of the compound of structure 2 and 1.46 g of trimethylolpropane trimethacrylate (Laromer TMPTMA, BASF), then 1.31 ml of 4,9-dioxadodecane-1,12-diamine (Baxxodur® EC 280, BASF) was added by pipette.

[0221] The mixture was applied on beech wood test specimens (Rocholl GmbH) and bonded and fixed with an overlap of 2 cm×4 cm. These were cured overnight at room temperature. After 12 h, the test specimens were bonded handtight. After 48 h, a tensile shear test was carried out at 100 mm/min.

[0222] The measured tensile shear strength was 1 MPa, this being 2 MPa after 8 days at room temperature (cohesion failure in each case).

Example 3

[0223] 2 g of the compound of structure 3 was mixed with 1.06 g of trimethylolpropane trimethacrylate (Laromer® TMPTMA, BASF), then 0.968 g of polyethyleneimine (Lupasol® FG, BASF) was mixed in and the mixture was stirred thoroughly.

[0224] The mixture was applied on stainless steel test specimens (Rocholl GmbH) and bonded and fixed with an overlap of 2.5 cm×2.5 cm. These were cured overnight at room temperature. After 12 h, the test specimens were bonded handtight. After 48 h, a tensile shear test was carried out at 100 mm/min. The measured tensile shear strength was 2.5 MPa (mixed cohesion/adhesion failure). The measured tensile shear strength after storage for 8 days at room temperature was 2.7 MPa.

Example 4

[0225] 2 g of the compound of structure 3 was mixed with 1.06 g of trimethylolpropane trimethacrylate (Laromer® TMPTMA, BASF), then 0.668 g of 1,3-diaminomethylcyclohexane (TCI) was mixed in and the mixture was stirred thoroughly.

[0226] The mixture was applied on stainless steel test specimens (Rocholl GmbH) and bonded and fixed with an overlap of 2.5 cm×2.5 cm. These were cured overnight at room temperature. After 12 h, the test specimens were bonded handtight. After 48 h, a tensile shear test was carried out at 100 mm/min. The measured tensile shear strength was 2.1 MPa (mixed cohesion/adhesion failure). The measured tensile shear strength after storage for 8 days at room temperature was 3 MPa.

Example 5

[0227] 2 g of the compound of structure 1 was mixed with 1.16 g of trimethylolpropane trimethacrylate (Laromer® TMPTMA, BASF), then 0.73 g of 1,3-bis(aminomethyl)cyclohexane (Sigma-Aldrich) was mixed in and the mixture was stirred thoroughly.

[0228] Measurement of peel strength at 23° C.

[0229] A spiral film applicator (Erichsen Coater) was used to immediately coat the mixture onto a PET film (Hostaphan® RN 36) (layer thickness 12 μm) and a further PET film was laminated on top of this and rolled on twice with a 2 kg roller. After 24 h at room temperature, the composite film was cut into strips 15 mm wide. The two films of the composite were clamped open at an angle of 90° in a tensile tester and the peel strength was tested at 100 mm/min. The measured peel strength was 2 N/15 mm.

[0230] A peel strength of greater than 1.5 N after 24 h is particularly suitable for applications of the adhesive in flexible packaging materials and for composite film lamination, in order to be industrially usable.

Example 6

[0231] 2 g of the compound of structure 4 was mixed with 1.4 g of trimethylolpropane trimethacrylate (Laromer® TMPTMA, BASF) and thickened with 0.35 g of HDK H13L silica gel (Wacker), then 0.883 g of 1,3-diaminomethylcyclohexane (TCI) was mixed in and the mixture was stirred thoroughly.

[0232] The mixture was applied on stainless steel test specimens (Rocholl GmbH) and bonded and fixed with an overlap of 2.5 cm×2.5 cm. These were cured overnight at room temperature. After 12 h, the test specimens were bonded handtight. After 48 h, a tensile shear test was carried out at 100 mm/min. The measured tensile shear strength was 11.5 MPa (adhesion failure).

[0233] The mixture was also applied on aluminum test specimens (Rocholl GmbH) and bonded and fixed with an overlap of 2.5 cm×2.5 cm. These were cured overnight at room temperature. After 12 h, the test specimens were bonded handtight. After 48 h, a tensile shear test was carried out at 100 mm/min. The measured tensile shear strength was 5 MPa (adhesion failure).

[0234] The mixture was also applied on ABS test specimens (Rocholl GmbH) and bonded and fixed with an overlap of 2.5 cm×2.5 cm. These were cured overnight at room temperature. After 12 h, the test specimens were bonded handtight. After 48 h, a tensile shear test was carried out at 100 mm/min. The measured tensile shear strength was 2.5 MPa (adhesion failure).

Example 7

[0235] 2 g of the compound of structure 5 was mixed with 1.12 g of trimethylolpropane trimethacrylate (Laromer® TMPTMA, BASF) and thickened with 0.15 g of HDK H13L silica gel (Wacker), then 1.09 g of 4,7,10-trioxa-1,13-tridecanediamine (BASF) was mixed in and the mixture was stirred thoroughly.

[0236] The mixture was applied on stainless steel test specimens (Rocholl GmbH) and bonded and fixed with an overlap of 2.5 cm×2.5 cm. These were cured overnight at room temperature. After 12 h, the test specimens were bonded handtight. After 48 h, a tensile shear test was carried out at 100 mm/min. The measured tensile shear strength was 5.7 MPa (adhesion failure).

[0237] The mixture was also applied on aluminum test specimens (Rocholl GmbH) and bonded and fixed with an overlap of 2.5 cm×2.5 cm. These were cured overnight at room temperature. After 12 h, the test specimens were bonded handtight. After 48 h, a tensile shear test was carried out at 100 mm/min. A measured tensile shear strength was 3.1 MPa (adhesion failure).

[0238] The mixture was also applied on ABS test specimens (Rocholl GmbH) and bonded and fixed with an overlap of 2.5 cm×2.5 cm. These were cured overnight at room temperature. After 12 h, the test specimens were bonded handtight. After 48 h, a tensile shear test was carried out at 100 mm/min. A measured tensile shear strength was 3.3 MPa (adhesion failure).

Example 8

[0239] 1 g of the compound of structure 4 was mixed with 0.7 g of trimethylolpropane trimethacrylate (Laromer® TMPTMA, BASF) and thickened with 0.1 g of HDK H13L silica gel (Wacker), then 0.62 g of 1,4-bis(3-aminopropyl) piperazine (BASF) was mixed in and the mixture was stirred thoroughly.

[0240] The mixture was applied on stainless steel test specimens (Rocholl GmbH) and bonded and fixed with an overlap of 2.5 cm×2.5 cm. These were cured overnight at room temperature. After 12 h, the test specimens were bonded handtight. After 48 h, a tensile shear test was carried out at 100 mm/min. The measured tensile shear strength was 9.4 MPa (adhesion failure).

[0241] The mixture was also applied on aluminum test specimens (Rocholl GmbH) and bonded and fixed with an overlap of 2.5 cm×2.5 cm. These were cured overnight at room temperature. After 12 h, the test specimens were bonded handtight. After 48 h, a tensile shear test was carried out at 100 mm/min. The measured tensile shear strength was 2.4 MPa (adhesion failure).

[0242] The mixture was also applied on ABS test specimens (Rocholl GmbH) and bonded and fixed with an overlap of 2.5 cm×2.5 cm. These were cured overnight at room temperature. After 12 h, the test specimens were bonded handtight. After 48 h, a tensile shear test was carried out at 100 mm/min. The measured tensile shear strength was 2.1 MPa (adhesion failure).

Example 9

[0243] 1 g of the compound of structure 4 was mixed with 1.59 g of bisphenol A glycerolate dimethacrylate (Sigma Aldrich), then 0.44 g of 1,3-diaminomethylcyclohexane (TCI) was mixed in and the mixture was stirred thoroughly.

[0244] The mixture becomes homogeneous and readily processable.

[0245] The mixture was applied on stainless steel test specimens (Rocholl GmbH) and bonded and fixed with an overlap of 2.5 cm×2.5 cm. These were cured overnight at room temperature. After 12 h, the test specimens were bonded handtight. After 48 h, a tensile shear test was carried out at 100 mm/min. The measured tensile shear strength was 6.4 MPa (adhesion failure). After a curing time of 48 h, further test specimens were stored for 7 days in a drying oven at 70° C. in steam in a closed vessel. After this, they were air-dried for 7 days at room temperature and a tensile shear test was carried out at 100 mm/min. The measured tensile shear strength was 2.4 MPa throughout (adhesion failure).

Example 10

[0246] 1 g of the compound of structure 4 was mixed with 1.15 g of bisphenol A bis glycidyl ether (BADGE) (Sigma Aldrich)), then 0.46 g of Jeffamine EDR 148 (Huntsman) was mixed in and the mixture was stirred thoroughly.

[0247] The mixture was applied on stainless steel test specimens (Rocholl GmbH) and bonded and fixed with an overlap of 2.5 cm×2.5 cm. These were cured overnight at room temperature. After 12 h, the test specimens were bonded handtight. After 48 h, a tensile shear test was carried out at 100 mm/min. The measured tensile shear strength was 15.3 MPa (adhesion failure).

[0248] After a curing time of 48 h, further test specimens were stored for 7 days in a drying oven at 70° C. in steam in a closed vessel. After this, they were air-dried for 7 days at room temperature and a tensile shear test was carried out at 100 mm/min. The measured tensile shear strength was 5.4 MPa throughout (adhesion failure).