TWO-COMPONENT SYSTEM HAVING IMPROVED ADHESION

Abstract

Described herein are two-component systems, a composite part comprising a coating made of the two-component system, a process for producing a composite part and a use of special siloxane-containing compounds. The addition of a polysiloxane-containing component, either chemically incorporated into the (meth)acrylate component or physically mixed into this component, results in an improved adhesion to a thermoplastic carrier.

Claims

1.-14. (canceled)

15. A two-component system comprising the components A) and B), wherein A) is at least one (meth)acrylate component based on (meth)acrylate monomers which is produced by reaction of the (meth)acryloyl units of at least the components A1) and A2), wherein A1) is at least one alkyl ester of (meth)acrylic acid and A2) is at least one hydroxyalkyl ester of (meth)acrylic acid which comprises a primary hydroxyl group and wherein the alkylene group of the hydroxyalkyl ester is linear and comprises 2 to 6 carbon atoms, wherein the component A) comprises exclusively primary hydroxyl groups and has a hydroxyl number of 80 to 500 mg KOH/g and B) is at least one polyisocyanate, wherein the component A) additionally comprises the component C), wherein C) is at least one dihydric or polyhydric alcohol and/or at least one polyaspartic ester, wherein (a) the component A) is produced by reaction of the (meth)acryloyl units of at least the components A1), A2) and A3), wherein A3) is at least one polysiloxane-containing (meth)acrylate and/or (b) the component A) additionally comprises the component D), wherein D) is a polysiloxane which comprises at least one group reactive toward component B).

16. The two-component system according to claim 15, wherein the components A) and B) altogether contain not more than 3% by weight of a solvent based on the total weight of the two-component system.

17. Two-component system according to claim 15, wherein the component A) is produced by reaction of the (meth)acryloyl units of at least the components A1) and A2), wherein A1) are at least two mutually distinct alkyl esters of (meth)acrylic acid and A2) are at least two mutually distinct hydroxyalkyl esters of (meth)acrylic acid which each have a primary hydroxyl group and wherein the alkylene groups of the hydroxyalkyl esters are each linear and comprise 2 to 6 carbon atoms.

18. The two-component system according to claim 17, wherein the component A2) comprises at least two mutually distinct hydroxyalkyl esters and the alkylene group of one hydroxyalkyl ester comprises 2 or 3 carbon atoms and the alkylene group of the at least one other hydroxyalkyl ester comprises 4 or 5 carbon atoms.

19. The two-component system according to claim 15, wherein the at least one polysiloxane-containing (meth)acrylate A3) conforms to the formula (I) ##STR00004## in which R.sub.1 represents an alkylene group, R.sub.2 each independently of one another represent an alkyl or aryl group, R.sub.3 represents an alkyl group, F represents an acryloxy or methacryloxy group and n represents the average number of repeating units and is between 1 to 70.

20. The two-component system according to claim 15, wherein the polysiloxane of the component D) conforms to the formula (II) ##STR00005## in which R.sub.1 each independently of one another represent an alkylene group, R.sub.2 each independently of one another represent an alkyl or aryl group, G each independently of one another represent an amino, mercapto, hydroxyl or hydroxypolyether group and n represents the average number of repeating units and is between 1 to 50.

21. The two-component system according to claim 15, wherein the at least one polyisocyanate of the component B) is selected from the group consisting of aromatic, araliphatic, aliphatic and cycloaliphatic polyisocyanates which optionally comprise iminooxadiazinedione, isocyanurate, uretdione, urethane, allophanate, biuret, urea, oxadiazinetrione, oxazolidinone, acylurea and/or carbodiimide structures.

22. A composite part comprising a carrier and at least one coating in direct contact with the carrier, wherein the carrier comprises a thermoplastic composition and the coating is obtained by curing the two-component system according to claim 15.

23. The composite part according to claim 22, wherein the thermoplastic composition of the carrier comprises at least one polycarbonate.

24. A process for producing a composite part comprising a carrier and at least one coating comprising the steps of: (i) providing a carrier, wherein the carrier comprises a thermoplastic composition, (ii) applying at least the two-component system according to claim 15, wherein the two-component system is in direct contact with the carrier, and (iii) curing the two-component system to afford a coating.

25. The process according to claim 24, comprising the process steps (i2) to (iv2), in which (i2) in a first process step the melt of a thermoplastic composition is injected into a first mould cavity and subsequently cooled to afford a carrier, (ii2) in a second process step the cavity of the injection moulding tool is enlarged to produce a gap, (iii2) in a third process step the two-component system according to claim 15 is injected into the thus produced gap of step (ii2) between the carrier of the process step (i2) and the mould surface of the enlarged cavity, wherein the two-component system according to claim 15 is cured in direct contact with the surface of the carrier to form a composite part and (iv2) in the fourth process step the composite part of step (iii2) is demoulded from the mould cavity, wherein the process steps (i2) to (iv2) follow one another in immediate succession.

26. A method comprising utilizing the composite part according to claim 22 as an interior or exterior component of a rail, aerospace or motor vehicle, for electricals/electronics components and IT components.

27. A method comprising utilizing at least one polysiloxane-containing (meth)acrylate as comonomer A3) in a (meth)acrylate component A) based on (meth)acrylate monomers which is a component of a two-component system which comprises A) at least the (meth)acrylate component based on (meth)acrylate monomers produced by reaction of the (meth)acryloyl units of at least the components A1), A2) and A3), wherein A1) is at least one alkyl ester of (meth)acrylic acid, A2) is at least one hydroxyalkyl ester of (meth)acrylic acid which comprises a primary hydroxyl group and wherein the alkylene group of the hydroxyalkyl ester is linear and comprises 2 to 6 carbon atoms and A3) is at least one polysiloxane-containing (meth)acrylate, wherein the component A) comprises exclusively primary hydroxyl groups and has a hydroxyl number of 80 to 500 mg KOH/g and B) comprises at least one polyisocyanate, wherein the component A) additionally comprises the component C), wherein C) is at least one dihydric or polyhydric alcohol and/or at least one polyaspartic ester, for improving the adhesion properties of the two-component system.

28. A method comprising utilizing a polysiloxane which comprises at least one group reactive toward polyisocyanate components in a two-component system comprising A) at least one (meth)acrylate component based on (meth)acrylate monomers produced by reaction of the (meth)acryloyl units of at least the components A1), A2) and optionally A3), wherein A1) is at least one alkyl ester of (meth)acrylic acid, A2) is at least one hydroxyalkyl ester of (meth)acrylic acid which comprises a primary hydroxyl group and wherein the alkylene group of the hydroxyalkyl ester is linear and comprises 2 to 6 carbon atoms and A3) is optionally at least one polysiloxane-containing (meth)acrylate, wherein the component A) comprises exclusively primary hydroxyl groups and has a hydroxyl number of 80 to 500 mg KOH/g and B) at least one polyisocyanate, wherein the component A) additionally comprises the component C), wherein C) is at least one dihydric or polyhydric alcohol and/or at least one polyaspartic ester, for improving the adhesion properties of the two-component system.

29. The method comprising according to claim 27, wherein the adhesion properties of the two-component system with respect to a carrier comprising at least one polycarbonate are improved.

Description

EXAMPLES

[0155] In the context of the present invention, the following methods have been used in addition to those measurement methods for determining OH groups and for determining acid number already stated above:

[0156] a) Viscosity, Determined Using Brookfield LV-DV-I+ Spindle Viscometer

[0157] Viscosities were determined by means of a Brookfield LV-DV-I+ spindle viscometer. Brookfield viscometers are rotary viscometers having defined spindle sets as rotary bodies. The rotary bodies used were from an LV spindle set. Owing to the temperature dependence of viscosity, the temperatures of the viscometer and of the measuring liquid were kept constant during the measurement, with an accuracy of +/−0.5° C. Materials used in addition to the LV spindle set were a thermostatable waterbath, a 0-100° C. thermometer (scale divisions 1° C. or smaller) and a timer (scale values not greater than 0.1 second). To perform the measurement, 100 ml of the sample were introduced into a wide-necked bottle and measured under temperature-controlled conditions in the absence of air bubbles after prior calibration. To determine viscosity the viscometer was positioned relative to the sample such that the spindle dips into the product up to the mark. Measurement is initiated using the start button and care was taken to ensure that the measurement took place in the favourable measurement region of 50% (+/−20%) of the maximum measurable torque. The result of the measurement was displayed by the viscometer in mPas and division by the density (g/ml) gives the viscosity in mm2/s.

[0158] b) Pendulum hardness according to König

[0159] For the pendulum hardness determination according to Konig (DIN 53157 or EN ISO 1522 April 2007 edition) the measure used is the damping of a swinging pendulum. The pendulum with two stainless steel balls is placed onto a coating film. There is a physical relationship between duration of pendulum swinging, amplitude, and the geometric dimensions of the pendulum. The viscoelastic behaviour of the coating is determinative for hardness. When the pendulum is set in swinging motion the balls roll on the surface and thus exert pressure on it. The greater or lesser recovery is dependent on elasticity. The absence of elastic forces causes severe damping of the pendulum movement. By contrast, high elastic forces cause only slight damping. Pendulum hardness according to “Konig”: number of swings in osc. 1 oscillation=1.4 seconds.

[0160] c) Crosshatch Testing

[0161] Adhesion was tested by means of crosshatch testing according to the standard DIN EN ISO 2409 (August 2007 edition).

[0162] d) Crockmeter Scratch Resistance

[0163] Scratch resistance was tested by means of a crockmeter according to the standard DIN 55654 (August 2015 edition).

[0164] e) Clouding Measurement

[0165] Haze measured according to the standard ASTM 1003 (2011 version) Ahaze is determined according to the following formula:

Δhaze=haze (crockmeter value)−haze (starting value)

[0166] e) Hydrolytic Ageing

[0167] The coated sample is subjected to hydrolytic ageing at 90±2° C. and 95±1% relative humidity for 72 hours in a climate test cabinet. The adhesion of the coated sample is tested by crosshatch testing (according to the standard DIN EN ISO 2409, August 2007 edition).

[0168] f) Glass Transition Temperature (Tg)

[0169] The glass transition temperature of the crosslinked polymer film consisting of the polyol component and the polyisocyanate curing agent is measured according to DIN EN ISO11357-1 (1997 edition). The measurement range was −50° C. to 150° C. at a heating rate of 10K/min.

Examples 1 to 5 and Comparative Example 6 (Embodiment (a))

[0170] In a polymerization vessel fitted with a dropping funnel, stirrer and cooler the process solvent methyl isobutyl ketone was initially charged and the raw materials were employed in the ratios as reported in table 1. The mercapto-functional regulator and the (meth)acrylate monomers and the initiator were uniformly added at the same temperatures over the course of three hours. Once addition was complete polymerization was carried out for a further 2 hours at the same temperature. The process solvent was then removed by distillation and the (meth)acrylate component was admixed with 1,3-butanediol.

TABLE-US-00001 TABLE 1 Comparative Raw material Example 1 Example 2 Example 3 Example 4 Example 5 example 6 tetrabutyl acrylate 20 20 20 20 20 20 hydroxyethyl 12 12 12 12 12 12 acrylate 4-hydroxybutyl 15 15 15 15 15 acrylate 2-hydroxypropyl 13.5 acrylate ethyl acrylate 48 43 48 43 51.5 53 A3)-1)* 5 10 A3)-2)** 5 10 1.5 1.5 1,3-butanediol 11 11 11 11 18 18 viscosity (mPa*s) 21 670 22 483 13 360 21 835 21 442 25 695 OH number (mg KOH/g) 258 250 245 244 309 269 AN (mg KOH/g) 7.5 0.8 0.7 0.8 1.1 1.1 *component A3)-1) represents a methacryloyl-functional polysiloxane of formula (I) where R.sub.1 = C.sub.3H.sub.6, R.sub.2 = CH.sub.3, R.sub.3 = CH.sub.3, F = —O—(C═O)—C(CH.sub.3)═CH.sub.2 and n = 8-9 **component A3)-2) represents a methacryloyl-functional polysiloxane of formula (I) where R.sub.1 = C.sub.3H.sub.6, R.sub.2 = CH.sub.3, R.sub.3 = CH.sub.3, F = —O—(C═O)—C(CH.sub.3)═CH.sub.2 and n = 27-30

Examples 7, 8 and 13 and Comparative Examples 9 to 12 (Embodiment (b))

[0171] In a polymerization vessel fitted with a dropping funnel, stirrer and cooler the process solvent methyl isobutyl ketone was initially charged and the raw materials were employed in the ratios as reported in table 2. The mercapto-functional regulator and the (meth)acrylate monomers and the initiator were uniformly added at the same temperatures over the course of three hours. Once addition was complete polymerization was carried out for a further 2 hours at the same temperature. The process solvent was subsequently removed by distillation and the binder admixed with the respective functionalized polydimethylsiloxane D) and 1,3-butanediol.

TABLE-US-00002 TABLE 2 Example Example Comparative Comparative Comparative Comparative Example Raw material 7 8 example 9 example 10 example 11 example 12 13 tetrabutyl 20 20 20 20 20 20 20 acrylate hydroxyethyl 12 12 12 12 12 acrylate 4-hydroxybutyl 15 15 15 15 15 acrylate 2-hydroxy-propyl 13.5 13.5 13.5 13.5 acrylate ethyl acrylate 53 53 51.5 51.5 54.5 54.5 53 D)-1)* 0.5 1.0 0.5 1.0 0.5 1.0 D)-2)** 1.5 1,3-butanediol 11 11 18 18 18 18 11 viscosity 20 847 20 500 19 400 20 300 27 644 19 400 20 600 (mPa*s) OH number 245 245 301 302 301 301 245 (mg KOH/g) AN (mg KOH/g) 0.9 1.0 0.8 0.9 0.5 0.8 1.0 *component D)-1) represents an alpha-omega-organomodified difunctional siloxane of formula (II) where R.sub.1 = C.sub.3H.sub.6, R.sub.2 = CH.sub.3, and G = —OC.sub.2H.sub.4OH where n = 8-0. **component D)-2) represents an alpha-omega-organomodified difunctional siloxane of formula (II) where R.sub.1 = C.sub.3H.sub.6, R.sub.2 = CH.sub.3 G = C.sub.6H.sub.13N and n = 30.

Comparative Example 14

[0172] In a polymerization vessel fitted with a dropping funnel, stirrer and cooler the process solvent methyl isobutyl ketone was initially charged and from a first dropping funnel the monomers 20 g of tetrabutyl acrylate, 12 g of hydroxyethyl acrylate, 15 g of 4-hydroxybutyl acrylate, 53 g of ethyl acrylate and the initiator, and from a second dropping funnel the mercapto-functional regulator, were added uniformly at the same temperature over three hours. Once addition was complete polymerization was carried out for a further 2 hours at the same temperature. The process solvent was then removed by distillation and the binder was admixed with 11 g of 1,3-butanediol.

[0173] Viscosity: 20 845 mPa*s

[0174] OH number: 244 mgKOH/g

[0175] Acid number: 0.9 mgKOH/g

Production of a Coating Example 15

[0176] From the corresponding components A) from the examples and comparative examples 1 and 14 a clear lacquer was produced as follows (table 3). Employed as comparison 1 is a branched polyester polyol based on the polyester building blocks isophthalic acid and adipic acid reacted with di- and trifunctional alcohols for in-mould coatings and the non-siloxane-modified comparative binder from example 14.

TABLE-US-00003 TABLE 3 Raw material CE15-1 15-2 15-3 15-4 15-5 15-6 CE15-7 15-8 15-9 CE15-10 CE15-11 CE15-12 CE15-13 CE15-14 15-15 Comparison 99 1 Comparative 99 example 14 Ex. 1 99 Ex. 2 99 Ex. 3 99 Ex. 4 99 Ex. 5 99 Comparative 99 ex. 6 Ex. 7 99 Ex. 8 99 Comparative 99 ex. 9 Comparative 99 ex. 10 Comparative 99 ex. 11 Comparative 99 ex. 12 Ex. 13 99 Tib kat 218 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 (1) Tego Wet 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 260 (2) B) (3) 174 80 80 80 80 100.5 100.5 79.2 79 97.6 97.3 97.6 97.6 79 79

[0177] (1) Tego Wet 260 is a substrate wetting additive from Evonik Industries AG (polyether siloxane copolymer)

[0178] (2) Tib Kat 218 is a catalyst from Tib Chemicals (dibutyltin dilaurate)

[0179] (3) Component B): aliphatic HDI trimer

[0180] The coatings from example 15 were applied to a 3.2 mm polycarbonate sheet (bisphenol A polycarbonate) having a visual transparency T.sub.VIS of 88% and an MVR of about 19 cm.sup.3/(10 min) measured at 300° C. and 1.2 kg loading (according to ISO 1133-1:2012-03) from Covestro Deutschland AG with a blade coater in a dry layer thickness of about 120 μm. The lacquer was then cured at 120° C. for 60 minutes in a recirculating drying oven.

[0181] Pendulum hardnesses according to Konig, scratch resistance by crockmeter and adhesion after hydrolytic ageing were then evaluated. The results are summarized in table 4.

TABLE-US-00004 TABLE 4 Glass Pendulum transition Crockmeter hardness temperature 2000 according of cured strokes, to Ko{umlaut over (n)}ig lacquer film 22.5N Adhesion after Coating in sec. in ° C. ΔHaze hydrolytic ageing CE15-1 124 58-60 0.1 GT 5 (complete detachment of the lacquer film from the substrate) 15-2 79 0 GT 2 15-3 69 0 GT 0 15-4 94 0 GT 0 15-5 48 36-40 0 GT 0 15-6 81 0.53 GT 3 CE15-7 69 28-30 0.1 GT 5 (complete detachment of the lacquer film from the substrate) 15-8 106 30-31 0 GT 0 15-9 76 0.2 GT 1 CE15-10 114 1.8 GT 5 (complete detachment of the lacquer film from the substrate) CE15-11 115 0.2 GT 4 CE15-12 85 0.2 GT 4 CE15-13 87 0.5 GT 5 CE15-14 80 18-22 44 GT 5 (complete detachment of the lacquer film from the substrate) 15-15 68 0.5 GT 0

[0182] As is apparent from the results of the table the addition of a siloxane component alone (CE15-7) or else the presence of primary hydroxyl groups in component A) alone (CE15-14) does not result in sufficient adhesion to the carrier. Only the combination of the addition of a siloxane component and the exclusive presence of primary hydroxyl groups in component A) results in good adhesion properties (15-2 to 15-6 and 15-8, 15-9 and 15-15).

[0183] Resistance against hand cream and sun cream and also against acetone and butyl acetate as solvents was also tested as reported in table 5.

[0184] For cream resistance a gauze bandage imbued with hand cream and sun cream was in each case placed on the surface of the coating followed by subjection to 80° C. in the recirculating oven for 24 hours. The damage to the lacquer surface was then visually assessed.

[0185] For solvent resistance an impregnated cotton pad was placed on the surface of the coating and damage to the lacquer surface was visually assessed after 1, 5, 15, 30 and 60 minutes.

TABLE-US-00005 TABLE 5 Acetone Butyl acetate Hand cream Sun cream 1, 5, 15, 30, 60 1, 5, 15, 30, 60 Coating 24 h 80° C. 24 h 80° C. min min CE15-1 1 2 1/2/2/2/2 1/1/1/2/2 15-2 1 2 1/2/3/3/3 1/1/1/2/2 15-3 1 2 1/2/3/3/3 1/1/1/2/2 15-4 1 2 1/2/3/3/3 1/1/1/2/2 15-5 1 1 1/2/2/3/3 1/1/1/2/2 15-6 1 1 1/2/2/3/3 1/1/1/2/2 CE15-7 2 2 1/2/3/3/3 1/1/1/1/1 15-8 2 2 1/2/3/3/3 1/1/1/2/2 15-9 2 1 1/2/3/3/3 1/1/1/2/2 CE15-10 2 2 1/2/3/3/3 1/1/1/2/2 CE15-11 2 2 1/2/3/3/3 1/1/1/2/3 CE15-12 1 2 1/1/1/3/3 1/1/1/1/1 CE15-13 1 2 1/1/3/3/3 1/1/1/1/1 CE15-14 1 2 1/1/3/3/3 1/1/1/1/1 15-15 1 2 1/1/3/3/3 1/1/1/1/1 Ranking/assessment: 1 = no change in lacquer surface 2 = slight damage to lacquer surface 3 = severe damage to lacquer surface

[0186] As is apparent from the results in table 5 the inventive coatings show good adhesion coupled with good resistances to hand cream and sun cream and to acetone and butyl acetate.