Use of compounds having n 2-oxo-1,3-dioxolane-4-carboxamide units in two-component adhesives

Abstract

A description is given of the use of compounds having n 2-oxo-1,3-dioxolane-4-carboxamide units as a reactive component in 2-component adhesives, especially for preparing hydroxypolyurethanes or hydroxypolycarbonates for adhesives applications, where n is a number greater than or equal to 2. A description is also given of corresponding two-component adhesives and adhesive bonding methods. Employed preferably as a second component of the two-component adhesive is a polyfunctional curing agent compound which is preferably selected from polyamines which have two or more amine groups and polyols which have two or more alcoholic hydroxyl groups.

Claims

1. A method for preparing a two-component adhesive, the method comprising: introducing a compound having n 2-oxo-1,3-dioxolane-4-carboxamide units as a reactive component into the two-component adhesive, wherein the compound having n 2-oxo-1,3-dioxolane-4-carboxamide units is represented by formula (I) ##STR00020## where R.sub.1 and R.sub.3 independently of one another are H or an organic radical; and R.sub.2 is an n-valent organic radical which is substituted by n−1 further 2-oxo-1,3-dioxolane-4-carboxamide groups where n is a number greater than 2, wherein the 2-oxo-1,3-dioxolane-4-carboxamide is a compound of formula (VII) ##STR00021## where ##STR00022##  is an alkoxylated glycerol radical having 2 to 5 C atoms in the alkoxy group, introducing a polyfunctional curing agent compound into the two-component adhesive, wherein the curing agent is selected from the group consisting of a polyamine which has two or more amine groups and a polyol which has two or more alcoholic hydroxyl groups.

2. The method according to claim 1, wherein in the formula (I) R.sub.1 is H, and R.sub.3 is H.

3. The method according to claim 1, wherein at least one of the compound having n 2-oxo-1,3-dioxolane-4-carboxamide units and the curing agent compound comprises at least one linear or branched spacer group having a molecular weight of at least 200 g/mol.

4. A two-component adhesive, comprising at least one compound having n 2-oxo-1,3-dioxolane-4-carboxamide units as a reactive, first component; wherein the compound having n 2-oxo-1,3-dioxolane-4-carboxamide units is represented by formula (I) ##STR00023## where R.sub.1 and R.sub.3 independently of one another are H or an organic radical; and R.sub.2 is an n-valent organic radical which is substituted by n−1 further 2-oxo-1,3-dioxolane-4-carboxamide groups, and at least one curing agent compound selected from the group consisting of a polyamine having two or more amine groups and a polyol having two or more alcoholic hydroxyl groups as a second component; wherein n is a number greater than 2, where either the compound having n 2-oxo-1,3-dioxolane-4-carboxamide units or the curing agent compound or both comprises at least one linear or branched flexible spacer group, where the flexible spacer group has a molecular weight of at least 200 g/mol; wherein the 2-oxo-1,3-dioxolane-4-carboxamide is a compound of formula (VII) ##STR00024## where ##STR00025##  is an alkoxylated glycerol radical having 2 to 5 C atoms in the alkoxy group, wherein the two-component adhesive has a bond strength of greater than 1.5 N/15 mm, measured as the peel strength of two polyester films bonded to one another with a 3 μm layer of adhesive and with an applied pressure of 3 bar after 24 hours.

5. The two-component adhesive according to claim 4, which at a temperature of 70° C. or below has a Brookfield viscosity of less than 10 000 mPa s, measured at 12 rpm with spindle 3.

6. The two-component adhesive according to claim 4, further comprising at least one catalyst for catalyzing the reaction of cyclocarbonate groups with the functional groups of the curing agent.

7. A method for bonding two substrates to one another, the method comprising: applying a two-component adhesive to a surface of at least one of the substrates, wherein the method for bonding is a laminating method producing laminated articles selected from high-gloss films, composite films, and laminated moldings, where a) a first substrate is provided in the form of a first film, b) a second substrate is provided, selected from paper, a second film, which may be identical to or different from the first film, and moldings, c) the two-component adhesive is applied to the first substrate and/or to the second substrate, and is optionally allowed to dry, and the first substrate is laminated onto the second substrate, wherein the lamination may optionally take place with thermal activation; wherein the two component adhesive comprises at least one compound having n 2-oxo-1,3-dioxolane-4-carboxamide units as a reactive component, wherein the compound having n 2-oxo-1,3-dioxolane-4-carboxamide units is represented by formula (I) ##STR00026## where R.sub.1 and R.sub.3 independently of one another are H or an organic radical; and R.sub.2 is an n-valent organic radical which is substituted by n−1 further 2-oxo-1,3-dioxolane-4-carboxamide groups, and n is a number greater than 2, wherein the 2-component lamination adhesive has a bond strength of greater than 1.5 N/15 mm, measured as the peel strength of two polyester films bonded to one another with a 3 μm layer of adhesive and with an applied pressure of 3 bar after 24 hours; wherein a polyfunctional curing agent compound is used as a second component of the two-component adhesive and is selected from polyamines which have two or more amine groups and polyols which have two or more alcoholic hydroxyl groups; wherein either the compound having n 2-oxo-1,3-dioxolane-4-carboxamide units or the curing agent compound or both comprise at least one linear or branched flexible spacer group, where the flexible spacer group has a molecular weight of at least 200 g/mol; wherein the 2-oxo-1,3-dioxolane-4-carboxamide is a compound of formula (VII) ##STR00027## where ##STR00028##  is an alkoxylated glycerol radical having 2 to 5 C atoms in the alkoxy group.

8. A film-laminated article, produced by the method according to claim 7.

9. A 2-oxo-1,3-dioxolane-4-carboxamide of formula (1) ##STR00029## where R.sub.1 and R.sub.3 independently of one another are H or an organic radical; and R.sub.2 is an n-valent organic radical which is substituted by n−1 further 2-oxo-1,3-dioxolane-4-carboxamide groups, n is a number greater than 2, and where between the 2-oxo-1,3-dioxolane-4-carboxamide groups there is at least one linear or branched spacer group having a molecular weight of at least 200 g/mol, wherein the 2-oxo-1,3-dioxolane-4-carboxamide is a compound of formula (VII) ##STR00030## where ##STR00031##  is an alkoxylated glycerol radical having 2 to 5 C atoms in the alkoxy group.

Description

EXAMPLES

(1) Example 1: Compound Having Three 2-Oxo-1,3-Dioxolane-4-Carboxamide Groups, Based on Ethoxylated/Propoxylated Glycerol

(2) ##STR00017##

(3) ##STR00018##

(4) =glycerol plus EO/PO

(5) M.sub.eq=1870 g/mol (molecular weight per cyclocarbonate group)

(6) Under a nitrogen atmosphere, 13.94 g of toluene 2,4-diisocyanates (TDI) (0.0825 mol) and 10.56 g of 2-oxo-1,3-dioxolane-4-carboxylic acid (0.08 mol) are dissolved in 70 ml of dry THF or acetone. 0.12 g (1 mol %) of 1,8-diazabicyclo-[5.4.0]undec-7-ene (DBU) is added and the reaction mixture is stirred at room temperature for 12 hours. Removal of the solvent by evaporation gives the product as a white solid in quantitative yield.

(7) The reaction may also take place in dry acetonitrile and with 4-DMAP as catalyst.

(8) In the presence of DBTL (dibutyltin dilaurate, 0.02% by weight), the product obtained may be reacted with Lupranol® 2095 (trifunctional polyether polyol having primary hydroxyl end groups) to give a difunctional prepolymer. For this purpose 5.0 g (0.0195 mol) of the product are dissolved in dry THF, and 31.2 g of Lupranol® 2095 (6.52 mmol) and 1.2 mg of DBTL (0.002 mmol) are added. The reaction mixture is heated at 60° C. for 4 hours. Removal of the solvent by evaporation gives the product in the form of a viscous yellow oil.

(9) Example 2

(10) Compound Having Three 2-Oxo-1,3-Dioxolane-4-Carboxamide Groups, Prepared from Glycerol Carbonate Carboxylic Acid (2-Oxo-1,3-Dioxolane-4-Carboxylic Acid) and Isocyanurate-Modified Hexamethylene Diisocyanate (Basonat® HI 100)

(11) Basonat HI 100:

(12) ##STR00019##

(13) 31.79 g of cyclocarbonate carboxylic acid (0.12 mol) in 80 ml of THF were introduced as an initial charge, giving a yellow solution. 0.3704 g of DMAP (4-(dimethylamino)-pyridine, 0.0012 mol) in 60 ml of THF was added. This was followed by the addition of 46.09 g of Basonat® HI100 (0.12 mol based on NCO; the NCO number of Basonat® HI 100 is 21.9%) in 80 ml of THF. This solution is stirred at room temperature for around 24 hours. The solution becomes cloudy overnight. Following removal of the THF by evaporation on a rotary evaporator, there remained 73.76 g of a yellow liquid of high viscosity. There was no NCO peak visible in the IR spectrum, and the NCO number was 1.1%.

(14) Example 3: Two-Component Adhesives

(15) The 2-oxo-1,3-dioxolane-4-carboxamides of example 1 and of example 2, respectively, were dissolved in THF at 23° C. and blended with different aminic hardeners (see table 1).

(16) Immediately after mixing, the resultant reactive two-component adhesive was applied in a layer thickness of 3 μm to a printed polyester film 36 μm thick. The solvent was evaporated by means of a stream of hot air and then, in a calender, a second polyester film 36 μm thick, treated beforehand by corona, was laminated onto the layer of adhesive under a pressure of 3 bar. The resulting laminate was cut into strips 15 mm wide, and the peel strength of these strips was determined at room temperature (20° C.) after 24 hours [N/15 mm]. This was done using a tensile testing machine, with the peel strength test conducted at a tensile angle of 90° (T test). The results are reproduced in table 1.

(17) Aminic Hardeners: DODDA: 4,9-dioxadodecane-1,12-diamine H.sub.2NCH.sub.2CH.sub.2CH.sub.2OCH.sub.2CH.sub.2CH.sub.2CH.sub.2OCH.sub.2CH.sub.2CH.sub.2NH.sub.2 DATOTD: 1,13-diamino-4,7,10-trioxatridecane H.sub.2NCH.sub.2CH.sub.2CH.sub.2OCH.sub.2CH.sub.2OCH.sub.2CH.sub.2OCH.sub.2CH.sub.2CH.sub.2N H.sub.2 DAP: 1,3-diaminopropane, H.sub.2NCH.sub.2CH.sub.2CH.sub.2NH.sub.2

(18) TABLE-US-00001 TABLE 1 Adhesive compositions and results of the peel strength measurements Peel 2-Oxo- strength 1,3-dioxolane- Aminic 24 h Example 4-carboxamides hardener [N/15 mm] 3.1 1872 g example 1 102 g DODDA 3.1 3.2 1872 g example 1 110 g DATOTD 4.5 3.3 1872 g example 1 37 g DAP 3.3 3.4 280 g example 2 240 g Polyetheramine 3.4 D 400 3.5 280 g example 2 37 g DAP 0.3 3.6 40 g Liofol ® 60 g Liofol ® 3.6 Comparative UR7732 UR 6084 Liofol ® UR7732/Liofol ® UR 6084: two-component polyurethane laminating adhesive composed ofisocyanate-based binder (Liofol ® UR7732) and polyol hardener (Liofol ® UR 6084)

(19) Especially suitable for industrial usefulness is a peel strength of greater than 1.5 N after 24 hours for applications of the adhesive in flexible packaging and for composite film lamination.