COPOLYMER MADE FROM CYCLIC EXO-VINYL CARBONATE ACRYLATES

Abstract

What are described are copolymers formed from (a) at least one monomer M1 of the formula

##STR00001##

in which R.sup.1 is an organic radical having a (meth)acryloyl group, R.sup.2, R.sup.3 and R.sup.4 are each independently a hydrogen atom or a C1- to C10-alkyl group; and (b) at least one ethylenically unsaturated, free-radically copolymerizable monomer M2 other than the monomers M1. What are also described are two-pack adhesives comprising the copolymers and a polyfunctional hardener. The copolymers and the two-pack adhesives can be used as laminating adhesives.

Claims

1: A copolymer, formed by free-radical copolymerization from (a) at least one monomer M1 of formula (I) ##STR00020## in which R.sup.1 is an organic radical comprising a (meth)acryloyl group, and R.sup.2, R.sup.3 and R.sup.4 are each independently a hydrogen atom or a C1- to C10-alkyl group; and (b) at least one ethylenically unsaturated, free-radically copolymerizable monomer M2 other than the at least one monomer M1.

2: The copolymer according to claim 1, wherein the at least one monomer M1 is used in an amount of 5% to 50% by weight, based on a total amount of all monomers, and the at least one monomer M2 is used in an amount of 50% to 95% by weight, based on the total amount of all the monomers.

3: The copolymer according to claim 1, wherein R.sup.1 is an organic radical comprising a total of not more than 24 carbon atoms and, apart from oxygen atoms, does not comprise any further heteroatoms.

4: The copolymer according to claim 1, wherein R.sup.1 is a group of formula (II) ##STR00021## in which X is a bond or an alkylene group comprising 1 to 18 carbon atoms and R.sup.5 is a hydrogen atom or a methyl group, or a group of formula (III) ##STR00022## in which m and p are each independently 0 or a number from 1 to 10, R.sup.5 is a hydrogen atom or a methyl group and R.sup.6 is a hydrogen atom or a C1- to C10-alkyl group, or a group of formula (IV) ##STR00023## in which s and t are each independently 0 or an integer from 1 to 10, R.sup.5 is a hydrogen atom or a methyl group and R.sup.7 is a hydrogen atom or a C1- to C10-alkyl group.

5: The copolymer according to claim 1, wherein R.sup.2 is a methyl group and R.sup.3 and R.sup.4 are each a hydrogen atom.

6: The copolymer according to claim 1, wherein the at least one monomer M2 is selected from the group consisting of a vinylaromatic hydrocarbon, an ester of a monoethylenically unsaturated C.sub.3-C.sub.8 monocarboxylic acid with a C.sub.1-C.sub.20-alkanol, a C.sub.5-C.sub.8-cycloalkanol, a phenyl-C.sub.1-C.sub.4-alkanol or a phenoxy-C.sub.1-C.sub.4-alkanol, a vinyl ester of an aliphatic carboxylic acid comprising 1 to 20 carbon atoms, and a conjugated diethylenically unsaturated C.sub.4-C.sub.10 olefin.

7: The copolymer according to claim 1, which has a glass transition temperature of 50 to +20 C.

8: A two-pack adhesive, comprising: a first pack comprising at least one copolymer according to claim 1 and a second pack comprising at least one polyfunctional hardener comprising at least two functional groups selected from the group consisting of a primary amino group, a secondary amino group, a hydroxyl group, a phosphine group, a phosphonate group, and a mercaptan group.

9: The two-pack adhesive according to claim 8, wherein a molar ratio of alkylidene-1,3-dioxolan-2-one groups in the copolymer to the functional groups in the hardener is from 1:10 to 10:1.

10: The two-pack adhesive according to claim 8, which is free of isocyanates and is either in a form of a solution in an organic solvent or in a solvent-free form.

11: The two-pack adhesive according to claim 8, wherein a laminate produced therewith has a shear strength of greater than 0.2 N after 1 minute and a shear strength of greater than 1 N after 24 hours, measured at 20 C.

12: The two-pack adhesive according to claim 8, further comprising at least one catalyst for reacting alkylidene-1,3-dioxolan-2-one groups of the copolymer with the functional groups of the hardener.

13: A process for producing a laminate, the processing comprising: laminating a film onto a substrate using at least one copolymer according to claim 1.

14: The process according to claim 13, wherein the substrate is at least one selected from the group consisting of a polymer film, a metal foil, paper, and a shaped body made from metal, plastic or wood.

15: A laminate, produced by the process according to claim 13.

16: An article, comprising the copolymer according to claim 1, wherein the article is an adhesive, a lacquer, a coating, a sealant, a paint, or an ink.

17: A method for producing flexible food packaging, the method comprising: introducing the article into the flexible food packaging.

18: A method for binding fibers and/or particles, the method comprising: binding the fibers and/or particles with the copolymer according to claim 1.

Description

EXAMPLES

[0171] ##STR00015##

1. Materials

2. Preparation Examples of Monomers

[0172] 2.1. Preparation of exoVC Acrylate 1

[0173] The preparation is effected in four stages.

[0174] The reaction scheme which follows comprises stages 1 to 3:

##STR00016##

1st Stage: Reaction of Hydroxypentanone with Acetylene to Give the Acetylene Adduct:

[0175] KOtBu (800 g, 7.1 mol) is initially charged in anhydrous THF (4.5 L) and cooled to 0-3 C. Acetylene (280 g, 10.8 mol) is introduced at this temperature within 3 h. While continuing to introduce acetylene (130 g, 5 mol), hydroxypentanone (550 g, 5.39 mol) is then added dropwise at 0-6 C. within 1 h. After passing through a viscosity maximum, this gives rise to an orange-brown solution. After stirring at 0-3 C. for a further 1 h, the mixture is warmed to RT, and ammonium chloride (1068 g in 5 L of water) is added at 20-25 C. within 45 min. This forms two phases. The organic phase is removed and dried over sodium sulfate, and the solvent is removed on a rotary evaporator at 40 C. and 5 mbar. 649 g of a brown oil are obtained. This is distilled in an oil-pump vacuum, observing a maximum bottom temperature of 130 C. The main fraction was obtained at 110-111 C. in the form of a yellow oil (440 g, 3.4 mol, 64%).

[0176] Purity (GC area %): 93%

2nd Stage: Reaction of the Diol with Formic Acid to Give the Formate:

[0177] The diol (1.305 kg, 10.2 mol) obtained in the first stage is initially charged and admixed at 7-8 C. with formic acid (1.512 L, 40 mol) within 1 h. Then the mixture is warmed to room temperature and the progress of the reaction is monitored by means of GC/FID. The reaction is allowed to run until there is virtually no more increase in the main peak, which is the case after about 4 h at RT. If the reaction is continued beyond this point, there is increasing formation of diformylated product. For workup, the mixture is first concentrated under reduced pressure, without heating, and the resulting crude product is then distilled at 12 mbar. The main fraction distills over at 112-115 C. as a clear yellow liquid (1.453 kg, 9.3 mol, 91%).

[0178] Purity (GC area %): 93%

3rd Stage: Ring Closure with CO.sub.2 to Give exoVC Formate

[0179] The formate obtained in the second stage (1.623 kg, 10.4 mol) is admixed with silver acetate (1.38 g) and TMTACN (N,N,N-trimethyl-1,4,7-triazacydononane, 13.8 mL), and CO.sub.2 is injected to 10 bar in a stirred autoclave with a pressure-retaining valve. Within 5 h, the temperature rises to 56 C. and the pressure to 18 bar. Once the temperature has dropped back to RT, the mixture is heated to 70 C. The pressure rises to about 28 bar. After about 4 h, monitoring of the reaction shows that there is virtually no more reactant (GC/FID). The mixture is cooled and decompressed. After adding dichloromethane (1.5 L), the contents of the autoclave are washed twice with HCl (10% solution, 480 mL each time) and dried over sodium sulfate, and the solvent is removed on a rotary evaporator (40 C., 60 mbar). Thereafter, while stirring at RT, all the constituents that are volatile under an oil-pump vacuum are removed, which can take up to 48 h. About 1.9 kg of crude product are obtained. For further purification, in a thin-film evaporator with a wiper system, volatile components are removed first (0.05-0.02 mbar, jacket temperature 109-114 C.). For this purpose, at least two runs are generally required. In a further run, the target compound is then separated from nonvolatile constituents (0.012 mbar, jacket temperature 170 C.).

[0180] Yield of exoVC formate: 1.419 kg (7.1 mol, 68%).

[0181] Purity (GC area %): 97%

4th Stage: Acrylation to Give exoVC Acrylate 1

##STR00017##

[0182] A two liter flat-bottom flask with Teflon stirrer, thermometer and condenser was charged with 300 g of exo-VC formate (1.5 mol) and 1200 g of methyl acrylate (14 mol). The methyl acrylate comprised 0.3 g of MeHQ (monomethyl ether of hydroquinone) as inhibitor. The mixture was stirred and heated to 40 C. 30 g of the enzyme Candida Antarctica Lipase B (immobilized form) were added. After 24 hours, the resultant mixture was decanted into a two liter round-bottom flask, leaving the enzyme in the flat-bottom flask. The methanol formed and, simultaneously, methyl acrylate were removed under reduced pressure. The residue was introduced back into the flat-bottom flask, which comprises the enzyme, together with 1000 g of fresh methyl acrylate. The resultant mixture was stirred at 40 C. for another 24 hours. The reaction mixture was cooled down to room temperature and filtered. Methanol and unconverted methyl acrylate were distilled off under reduced pressure.

[0183] The yield was 339 g of exo-VC acrylate 1.

[0184] Purity: 96.7% (determined by gas chromatography)

2.2 Preparation of exoVC Acrylate 2

[0185] The preparation is effected in four stages.

[0186] The following reaction scheme comprises stages 1 to 3:

##STR00018##

1.) Ethynylation of 4,4-dimethoxybutan-2-one

[0187] TMS-acetylene (982 g, 10 mol) is initially charged under argon in THF (17 L, dried over molecular sieve) and cooled down to 68 C. While stirring, within 1 h, n-butyllithium (2.5 M in hexane, 4 L) is added dropwise at 68 C. and stirred for a further 1 h. Within 30 min, the ketone (1.319 kg, 10 mol) is then added dropwise at 68 C. to 54 C. and the mixture is subsequently stirred for a further 15 min. Thereafter, the mixture is warmed to 9 C. and water (2.9 L) is added in one portion. The temperature rises to about 17 C. The reaction mixture is concentrated thoroughly at 450 C./8 Torr. By GC analysis, it is ensured that no TMS-protected product is present any longer. The residue is suspended in diethyl ether (750 mL) and filtered, and the filtration residue is washed once again with diethyl ether. The filtrate is concentrated under reduced pressure. About 1.2 kg of raw material remain as a brown liquid. By vacuum distillation (5 mbar), about 1.1 kg (7 mol, 70%) of ethynylated product are obtained therefrom at 64-68 C. as a colorless oil.

[0188] Purity: >96% (GC area %)

2.) Ring Closure with CO.SUB.2

[0189] The acetylene alcohol obtained in stage 1 (1233 g; 7.79 mol) is initially charged in acetonitrile (1.2 L) and, in a stirred autoclave. PMDETA (pentamethyldiethylenetriamine; 138.9 g; 0.8 mol) and AgOAc (12.9 g; 0.078 mol) are added. CO.sub.2 is injected to 50 bar and the mixture is stirred for 2.5 h. The temperature rises up to 75 C. After cooling to room temperature, the reaction mixture is decompressed to standard pressure, filtered and concentrated at 100 C./5 mbar. About 1.5 kg of raw material remain as a brown liquid. By vacuum distillation at 5 mbar, about 1.39 kg of the carbonate are obtained therefrom at 114-115 C. as an orange oil which crystallizes through overnight (possibly after addition of a few seed crystals).

[0190] The mass of crystals is stirred with cyclohexane (1.34 L) and filtered with suction, and the residue is washed once again with cyclohexane (0.45 L). After drying under reduced pressure, 1.29 kg (6.38 mol, 64%) of almost colorless solids are obtained.

[0191] Purity: >99% (GC area %)

3.) Transacetalization with Trimethylolpropane

[0192] The dimethoxy-substituted carbonate from stage 2 (250 g, 1.24 mol) is initially charged in 1.4 L of acetonitrile under an argon atmosphere. Then 253 g (1.87 mol) of trimethylolpropane and 407 mg (0.002 mol) of p-toluenesulfonic acid hydrate are added. The mixture is heated under reflux for 10 h. After cooling to room temperature, the solvent is removed under reduced pressure and the residue is taken up in about 1 L of MTBE. The mixture is washed four times with 300 ml each time of water. The organic phase is dried with sodium sulfate, filtered and concentrated on a rotary evaporator. This is followed by drying at 40 C. in an oil-pump vacuum for several hours. The product is obtained as a viscous, pale yellowish oil (339 g) in the form of two isomers, which crystallizes gradually when left to stand at room temperature for a prolonged period.

[0193] Purity: >98% (GC area %)

4.) Acrylation to Give exoVC Acrylate 2

[0194] ##STR00019##

[0195] A two liter flat-bottom flask with Teflon stirrer, thermometer and condenser was charged with 129 g of exo-VC-PMP alcohol (0.47 mol), 409 g of methyl acrylate (4.75 mol) and 152 g of 5 molecular sieve powder. The methyl acrylate comprised 0.3 g of MeHQ (monomethyl ether of hydroquinone) as inhibitor. The mixture was stirred and heated to 60 C. 9.7 g of the enzyme Candida Antarctica Lipase B (immobilized form) were added. After 72 hours, 100 g of 5 molecular sieve powder and 9.7 g of the enzyme Candida Antarctica Lipase B (immobilized form) were added. After 96 hours, the reaction mixture was cooled to room temperature and filtered. Methanol and unconverted methyl acrylate were distilled off under reduced pressure.

[0196] The yield was 153 g of exoVC acrylate 2.

[0197] Purity: 97.1% (determined by gas chromatography)

3. Preparation Examples of Copolymers

[0198] 3.1 Copolymer of exoVC Acrylate 1 and n-butyl Acrylate

[0199] A polymerization apparatus consisting of glass reactor, reflux condenser, stirrer and nitrogen inlet is initially charged with 864.9 g of methyl ethyl ketone (MEK) under a gentle nitrogen stream and heated to 80 C. 15 g of a monomer mixture consisting of 225 g of n-butyl acrylate and 75 g of exoVC acrylate 1 are added. After 80 C. has been reached again, 1.7 g of an initiator solution composed of 4 g of tert-butyl perpivalate (75% in mineral oil) and 30 g of MEK are added and initial polymerization is effected for 3 min. Then the remaining 285 g of monomer mixture and 32.3 g of initiator solution are run in within 3 h. Subsequently, the temperature is increased to 90 C. and a solution of 0.96 g of tert-butyl perpivalate (75% in mineral oil) in 15 g of MEK is added within 30 min. Thereafter, the mixture is cooled.

[0200] K value; 1% in THF: 27

[0201] Solids content: 22.9%

3.2 Analogously to Example 1, it is Possible to Prepare a Copolymer with exoVC Acrylate 2.

4. Two-Pack Adhesive

[0202] The copolymer described in example 3.1 was blended with 2% by weight of isophoronediamine (IPDA) as hardener and the resulting reactive two-pack adhesive, immediately after mixing, was applied in a layer thickness of 3 m, on the printed side, to a printed polyester film of thickness 12 m. The solvent was evaporated by means of a hot air stream and then, in a calender, a polyethylene film of thickness 60 m, which had been provided with a corona treatment beforehand, was laminated onto the adhesive layer under a pressure of 3 bar. The resulting laminate was cut into strips of width 15 mm and the peel strength of these strips was determined at room temperature (20 C.) a) after 1 min and b) after 24 h [N/15 mm]. This was done using a strength tester, and the peel strength test was conducted at a tearing angle of 90 (T test). The results are shown in table 1.

[0203] In an analogous manner, it is possible to produce and use a two-component adhesive with the copolymer of example 3.2.

TABLE-US-00001 TABLE 1 Results of the peel strength measurements Peel strength after 1 min Peel strength after 24 h [N/15 mm] [N/15 mm] Example 3.1 blended with 0.3 1.4 2% by weight of IPDA Example 3.1 without IPDA <0.1 <0.1 (comparison, one-pack adhesive)

[0204] A peel strength of greater than 0.2 N after 1 min and greater than 1 N after 24 h is sufficient for applications of the adhesive in flexible packaging, and builds up within a sufficiently short time to be utilizable industrially.