Adhesive dual-component composition based on polyurethane

Abstract

The invention relates to an adhesive dual-component composition comprising a composition A based on a polyurethane prepolymer with cyclocarbonate terminations and a composition B based on a mixture comprising at least one diamine B1 comprising only two primary amine groups of the CH.sub.2NH.sub.2 type and at least one polyamine B2 comprising at least three primary amine groups of the CH.sub.2NH.sub.2 type. The invention also relates to a multilayer structure produced from the adhesive composition according to the invention and to the method for the production thereof.

Claims

1. An adhesive composition comprising: a composition A comprising at least one cyclocarbonate-terminated polyurethane prepolymer, and a composition B comprising: at least one diamine B1 comprising only two CH.sub.2NH.sub.2 groups, and at least one polyamine B2 comprising at least three CH.sub.2NH.sub.2 groups, wherein the diamine B1:polyamine B2 weight ratio ranges from 30/70 to 70/30.

2. The composition as claimed in claim 1, wherein the cyclocarbonate-terminated polyurethane prepolymer is obtained by reacting an NCO-terminated polyurethane and a glycerol cyclocarbonate.

3. The adhesive composition as claimed in claim 1, wherein the cyclocarbonate-terminated polyurethane prepolymer is prepared by a process comprising the following steps: E1) preparing an NCO-terminated polyurethane prepolymer by a polyaddition reaction comprising reacting at least one polyisocyanate selected from the group consisting of diisocyanates and triisocyanates with at least one polyol selected from the group consisting of polyether polyols and polyester polyols, and mixtures thereof; followed by E2) reacting the product formed in the first step E1) with at least one glycerol cyclocarbonate in an amount such that all of the NCO groups present in the reaction medium at the end of step E1) react in the presence of the glycerol carbonate.

4. The adhesive composition as claimed in claim 3, wherein at least one polyol is selected from polyester polyols.

5. The adhesive composition as claimed in claim 1, wherein the diamine or the mixture of diamines B1 has a primary alkalinity ranging from 3.00 to 20.00 meq/g.

6. The adhesive composition as claimed in claim 1, wherein the polyamine or the mixture of polyamines B2 has a primary alkalinity from 8.00 to 21.00 meq/g.

7. The adhesive composition as claimed in claim 1, wherein the composition B has a ratio of the primary alkalinity to the total alkalinity ranging from 0.25 to 0.70.

8. The adhesive composition as claimed in claim 1, wherein the molar ratio of the number of primary amine functions to the number of cyclocarbonate functions ranges from 0.8 to 1.2.

9. The adhesive composition as claimed in claim 1, further comprising at least one crosslinking catalyst.

10. A ready-to-use kit comprising the adhesive composition as claimed in claim 1, wherein the compositions A and B are packaged in two separate compartments.

11. A multilayer structure comprising at least two layers of material bonded together by an adhesive layer, wherein said adhesive layer comprises the adhesive composition as claimed in claim 1, in a crosslinked state.

12. The multilayer structure as claimed in claim 11, wherein the adhesive layer has a thickness ranging from 1.5 to 5 m.

13. The multilayer structure as claimed in claim 11, comprising at least one layer of aluminum-based material.

14. A process for manufacturing a multilayer structure as claimed in claim 11, comprising the following steps: mixing the composition A and the composition B to form a mixture, then coating said mixture over a surface of a first layer of material to form a coated surface, then laminating a surface of a second layer of material over said coated surface, then crosslinking said mixture.

15. The manufacturing process as claimed in claim 14, wherein the mixture of the composition A and the composition B comprises at least one solvent and wherein the process further comprises a step of evaporating the solvent(s).

Description

EXAMPLES

(1) The following ingredients were used:

(2) Composition A

(3) Voranol P 400: difunctional polypropylene glycol having a hydroxyl value OHV ranging from 250 to 270 mg KOH/g (available from Dow);

(4) Voranol CP 450: trifunctional polypropylene glycol having a hydroxyl value OHV ranging from 370 to 396 mg KOH/g (available from Dow);

(5) Realkyd XTR 10410: difunctional polyester polyol having a hydroxyl value OHV ranging from 108 to 116 mg KOH/g (available from Arkema);

(6) Scuranate TX: toluene diisocyanate (TDI) having 48.1% by weight of NCO functions and comprising 95% by weight of 2,4-TDI isomer (available from Vencorex);

(7) Desmodur N3300: isocyanurate of hexamethylene diisocyanate (HDI) (available from Covestro);

(8) Jeffsol GC: glycerol carbonate having a purity of 93% by weight (available from Huntsman);

(9) ethyl acetate: solvent

(10) Borchi Kat 315: catalyst based on bismuth neodecanoate (available from Borchers);

(11) Tyzor Pita: catalyst based on titanium ethylacetoacetate (available from Dorf Ketal);

(12) Silquest A1110: adhesion promoter of (3-aminopropyl)trimethoxysilane type (available from Momentive).

(13) The polyol(s) is (are) dried before being reacted with the polyisocyanate(s) used for the synthesis of the polyurethane prepolymer.

(14) Composition B

(15) Jeffamine ED 148 (available from Huntsman): diamine (of B1 type) having a molar mass of 148.20 g/mol and a primary alkalinity of 13.49 meq/g and corresponding to the formula H.sub.2NCH.sub.2CH.sub.2OCH.sub.2CH.sub.2OCH.sub.2CH.sub.2NH.sub.2. Jeffamine ED 148 has a primary alkalinity/total alkalinity ratio of 1.00 determined by potentiometric analysis;

(16) Lupasol FG (available from BASF): polyamine (of B2 type) having a molar mass of 800 g/mol and a primary alkalinity of 9.75 meq/g and corresponding to the general formula (IV):

(17) ##STR00029##
s being as defined above.
Lupasol FG has a primary alkalinity/total alkalinity ratio of 0.42 determined by .sup.13C NMR.
H.sub.2N(CH.sub.2).sub.10NH.sub.2: diamine (of B1 type) having a molar mass of 172 g/mol and a primary alkalinity of 11.61 meq/g.
H.sub.2N(CH.sub.2).sub.10NH.sub.2 has a primary alkalinity/total alkalinity ratio of 1.00, determined by potentiometric analysis.

Example 1: Preparation of a Composition A-1 Based on a Cyclocarbonate-Terminated Polyurethane Prepolymer Based on Polyether Polyols and Polyester Polyols

(18) 190.7 g of Scuranate TX are introduced into a reactor and heated at 40 C. Next, 22.7 g of Voranol CP 450, then 103.3 g of Voranol P 400 are introduced in turn making sure that the temperature of the mixture does not exceed 80 C. When the mixture temperature is stabilized, the mixture is heated for around 1 hour at 80-85 C., then cooled to 70 C. Next, 321.6 g of Realkyd XTR 10410 are introduced making sure that the temperature of the mixture does not exceed 90 C.

(19) The mixture is kept at 90 C. for around 3 hours. The end of the reaction is followed by monitoring the weight percentage of NCO functions in the medium, the latter having to be, in theory, around 5.7%. When the reaction is finished, the mixture is cooled to 70 C. and 103.4 g of glycerol carbonate and 0.5 g of Tyzor Pita are introduced. 100 g of ethyl acetate and 7.5 g of Silquest A1110 are added then the mixture is kept at 70 C. for 6 to 8 hours until there are no more NCO functions visible in the infrared (IR) (disappearance of the band characteristic of the NCO function at around 2250 cm.sup.1).

(20) When the weight percentage of NCO functions is less than 0.1% (no more visible NCO band), 150 g of ethyl acetate are introduced. The viscosity of the composition A-1 thus obtained is measured at D+1, i.e. 24 hours after the end of the reaction (disappearance of the NCO band visible in the IR), with the aid of a Brookfield viscometer (spindle 3, 20 rpm). The viscosity of the composition A-1 at 23 C. is around 3900 mPa.Math.s.

(21) The cyclocarbonate function content of the cyclocarbonate-terminated polyurethane prepolymer is around 0.82 meq/g.

Example 2: Preparation of a Composition A-2 Based on a Cyclocarbonate-Terminated Polyurethane Prepolymer Based on Polyether Polyols and Polyester Polyols

(22) 143.2 g of Scuranate TX are introduced into a reactor and heated at 40 C. 22.6 g of Voranol CP 450 are slowly introduced and the mixture is heated at 50 C. Next, 101.6 g of Voranol P 400 are added. The exotherm of the reaction mass increases to around 70 C. Once the exotherm is controlled, the mixture is kept at 70 C. After reacting for one hour, 241.4 g of Realkyd XTR 10410 are introduced. The exotherm of the reaction mass increases up to around 85 C. The mixture is kept at 85 C. for around 2-3 hours. The end of the reaction is followed by monitoring the weight percentage of NCO functions in the medium, the latter having to be, in theory, around 4.4% by weight. When the reaction is finished, the mixture is cooled to 70 C. and 76.6 g of Desmodur N3300 and 100 g of ethyl acetate are introduced. The mixture is homogenized for 20 minutes then 114 g of Jeffsol GC are added. 0.45 g of Tyzor Pita is added, then the mixture is kept at 80-85 C. for 3 hours until there are no more NCO functions visible in the IR (disappearance of the band characteristic of the NCO function at around 2250 cm.sup.1).

(23) When the weight percentage of NCO functions is less than 0.1% (no more visible NCO band), 200 g of ethyl acetate are introduced. The viscosity of the composition A-2 thus obtained is measured at D+1, i.e. 24 hours after the end of the reaction (disappearance of the NCO band visible in the IR), with the aid of a Brookfield viscometer (spindle 3, 20 rpm). The viscosity of the composition A-2 at 23 C. is around 3000 mPa.Math.s.

(24) The cyclocarbonate function content of the cyclocarbonate-terminated prepolymer is around 0.90 meq/g.

Example 3: Preparation of the Compositions B

(25) The compositions B which were tested were prepared by simple mixing of the diamine B1 (Jeffamine ED 148 or H.sub.2N(CH.sub.2).sub.10NH.sub.2) and/or of the polyamine B2 (Lupasol FG) at ambient temperature (around 23 C.) in a B1/B2 weight ratio indicated below in table 1.

Example 4: Preparation of the Adhesive Compositions

(26) The mixing of the compositions A and B described in detail in examples 1 to 3 was carried out in an A/B weight ratio indicated below in table 1.

(27) TABLE-US-00001 TABLE 1 characteristic of the adhesive compositions tested B1/B2 A/B NH.sub.2/CC molar nature of A nature of B ratio ratio ratio Composition 1 A-1 Jeffamine ED148 100/6.5 0.93 (comparative) Composition 2 A-1 B2 100/7 0.83 (comparative) Composition 3 A-1 Jeffamine ED148 + 1/1 100/6.8 0.96 B2 Composition 4 A-1 H.sub.2N(CH.sub.2).sub.10NH.sub.2 + 1/1 100/25 0.94 B2.sup.(1) Composition 5 A-2 Jeffamine ED148 + 1/1 100/8.3 0.93 B2 Composition 6 A-2 Jeffamine ED148 + 8/2 100/7.6 0.93 (comparative) B2 .sup.(1)the composition B comprising the mixture of B1 and B2 was diluted to 29% by weight in an ethanol solvent. Compositions 1 to 6 were prepared either from the composition A of example 1 (A-1) or from the composition A of example 2 (A-2). Compositions 3 to 5 according to the invention were prepared from a composition B comprising a diamine of B1 type and a polyamine of B2 type. Comparative compositions 1 and 2 were prepared respectively from the diamine B1 (composition 1) and from the polyamine B2 (composition 2). Comparative composition 6 was prepared from a composition B, the B1/B2 weight ratio of which is too high. The NH.sub.2/CC ratio represents the molar ratio of the number of primary amine functions to the number of cyclocarbonate functions present in the adhesive composition (A + B).

Example 5: Preparation of the Complexes

(28) Preparation of the supports: the layers of material are cut to the desired format and stapled to a Bristol record card. Preparation of the adhesive composition: the composition A and the composition B are mixed in a glass flask, with an optional addition of ethyl acetate. In the latter case, the solids content of the adhesive composition is around 30% by weight in order to have a spread of the order of 3.5 to 5 g/m.sup.2 for each of the interfaces between two substrates. Production of the multilayer (complex) structure: the adhesive is applied to an aluminum layer reinforced with polyethylene terephthalate (PET) with the aid of an applicator with a Mayer rod, clips are used to hold the support on the Bristol record card on the non-stapled side and the support is placed in a ventilated oven for 2 minutes at 105 C. to evaporate the solvent, the adhesive-coated support and the support to be laminated are stapled together over one edge. The clips are removed and the lamination takes place with the aid of a press roller, the complexies placed in a press and left is crosslink either at ambient temperature or in a ventilated oven at 40 C. in a press (metal plates).

(29) Various complexes were prepared using a PET12/ALU9/CPP70 three-layer system defined below, each layer being separated by an adhesive layer as described in detail in table 2 below:

(30) TABLE-US-00002 TABLE 2 characteristic of the complexes Adhesive composition Spread (g/m.sup.2) Film 1 Composition 1 (comparative) 4.3 Film 2 Composition 2 (comparative) 4.3 Film 3 Composition 3 4.5 Film 4 Composition 4 3.8 Film 5 Composition 5 4.5 Film 6 Composition 6 (comparative) 4.8

(31) PET12/ALU9/CPP70: system consisting of a layer of polyethylene terephthalate with a thickness of 12 m (PET12), a layer of cast polypropylene with a thickness of 70 m (CPP70) and a thin layer of aluminum with a thickness of 9 m (ALU9) positioned between the two PET12 and CPP70 layers.

Example 6: Measurement of the Cohesion of the Complexes of Example 5 Before and after Sterilization Test and Qualitative Assessment of the Resistance of Said Complexes to Sterilization

(32) 180 Peel (Measurement of the Cohesion):

(33) The cohesion of the complex is evaluated by the 180 peel test as described in French standard NF T 54-122. The principle of this test consists of the determination of the force necessary for separating (or peeling) 2 individual layers of complex bonded by the adhesive.

(34) A test specimen of rectangular shape, 15 mm wide and around 15 cm long, is cut from the two-layer complex. The test specimens are cut in the machine direction of the coating operation. The two individual layers of complex included in this strip are manually detached from the end of this test specimen, and over approximately 2 cm, and the two free ends thus obtained are attached to two holding devices respectively connected to a stationary part and a movable part of a tensile testing device which are located on a vertical axis.

(35) While a drive mechanism imparts a uniform rate of 100 mm/minute to the movable part, resulting in the detachment of the two layers, the detached ends of which gradually move along a vertical axis forming an angle of 180, the stationary partconnected to a dynamometer DY30measures the force withstood by the test specimen thus held, which force is measured in newtons (N).

(36) Each test is repeated 3 times and the mean value of the three measurements is indicated in table 3 below.

(37) The measurement of the cohesion before sterilization was carried out 7 days after the manufacture of the multilayer film (D+7).

(38) As illustrated in table 3 below, the cohesion was also measured 24 hours after sterilization.

(39) Qualitative Assessment of the Resistance to Sterilization

(40) The quality of the adhesion between the layers of material of the multilayer structures tested was also evaluated after sterilization.

(41) In particular, the presence or absence of blisters, which may be of various shapes (for example channels or domes), or bubbles was noted. The presence of these deformations of the multilayer structure leads to infiltration of water between the layers of the multilayer structure resulting in the degradation of the adhesive during the sterilization.

(42) Moreover, it was verified whether the adhesive is de-crosslinked during the sterilization. For this, after having carried out the peel test described above on each of the films tested, the presence or absence of tack was evaluated by exerting a slight pressure of the index finger on the surface of the layer of adhesive left visible after separation of the layers of material.

(43) The observations are recorded in table 3 below.

(44) Sterilization Test

(45) In the present example, the sterilization test was carried out once the adhesive was crosslinked within the complex (around 7 days after preparation of the complex in accordance with example 5). Sachets were prepared from a complex prepared in example 5, without sealing the fourth side. The sachets are placed on the shelf of an autoclave (vapor phase) and left for 1 hour at 130 C. in the autoclave under 3 bar.

(46) TABLE-US-00003 TABLE 3 Cohesion measurement Film 1 Film 2 Film 6 comparative comparative Film 3 Film 4 Film 5 comparative Before Time t (D + 7) (D + 7) (D + 7) (D + 7) (D + 7) (D + 7) sterilization Cohesion at 4.5 5.7 4.8 6 4.8 5.5 time t (N/15 mm) Observations tack no tack- no tack- no tack- no tack- no tack- at time t Al tear Al tear Al tear Al tear Al tear 24 h after Cohesion 0.15 3 4.1 3 4.4 5 sterilization (N/15 mm) Observations tack tack no tack no tack no tack tack channels no no no channels channels channels channels

(47) In table 3 above: when no tack is observed, then the film passes the sterilization test, when tack is observed, then the film does not pass the sterilization test, when channels are observed, then the film does not pass the sterilization test, when a tear is observed, then the film passes the sterilization test.