WO2009141080A1

WO2009141080A1 - Plastic composite elements and method for the production thereof

Info

Publication number: WO2009141080A1
Application number: PCT/EP2009/003385
Authority: WO
Inventors: Catherine LÖVENICH; Eva Emmrich; Manfred Schmidt
Original assignee: Bayer Materialscience Ag
Priority date: 2008-05-23
Filing date: 2009-05-13
Publication date: 2009-11-26
Also published as: DE102008024865A1

Abstract

The present invention relates to composite elements composed of a thermoplastic material layer and a polyurethane layer, to a method for the production thereof, and to the use thereof.

Description

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Plastic composite elements and a method for their production

The invention relates to composite elements of a plastic layer and a polyurethane layer, a process for their preparation and their use.

Polyisocyanate polyaddition products obtainable by reacting isocyanates with isocyanate-reactive compounds, for example, polyols, i. Compounds having at least two hydroxyl groups as well as composite elements of these products with other plastics are well known. Exposing these composite elements to high temperatures and humidities often leads to undesired detachment of the plastics from the polyisocyanate polyaddition products. In particular, when using such composite elements in the automotive industry, for which such a burden can not be excluded, a replacement of the polyisocyanate polyaddition of the other plastics and thus destruction of the composite element is not acceptable.

In the production of the composite elements, in particular the polyisocyanates used for this purpose, the problem may arise that they do not give stable mixtures at low temperatures. Especially at very low temperatures, for example below 0 ^° C., these polyisocyanates may tend to crystallize out. Especially for the reproducible production of high quality products, however, it is important to avoid this problem.

DE-A 10 022 280 describes a process for producing composite elements of thermoplastics and polyurethanes with improved adhesion and moisture aging properties. The composite is used, for example, for the manufacture of instrument panels, which panels are usually made of a thermoplastic substrate [such as a thermoplastic). Polypropylene, polycarbonate / acrylonitrile-butadiene-styrene (PC / ABS) or acrylonitrile-butadiene-styrene (ABS)], a polyurethane (PUR) foam and another decorative layer (often called "skin") of polyvinyl chloride (PVC), thermoplastic Polyolefins (TPO), thermoplastic polyurethanes (TPU), polyurethane spray skins, etc. By the use of isocyanate groups containing ester groups

Polyester prepolymers for the production of polyurethane foams according to DE-A 10 022 280 have improved properties, in particular a good adhesion between the thermoplastic and such polyurethane foams. In a moist storage of such a composite up to 80 hours at 80 ⁰ C and 80% relative humidity is also an intact composite of thermoplastic and polyurethane foam before.

Another possibility for the production of composite components is shown in EP-A 1 531 173, in which isocyanate-polycarbonate prepolymers for the production of polyurethane foams with improved adhesion to other thermoplastics in wet aging are described. - -

No. 5,300,531 describes the use of fatty acid amides for improving the adhesion to or avoiding blisters with a PVC decorative layer. It is preferred to use polymeric diphenylmethane diisocyanate (MDI) mixtures as the polyisocyanate component.

The currently available systems provide adhesion values measured according to the

Measuring method PV 2034 of Volkswagen AG before aging of> 10 N / 5 cm. After heat storage (500 h storage at 120 ⁰ C circulating air), climate change test (storage 12 cycles (= 144 h) according to the measuring method PV 1200 of Volkswagen AG) or solar simulation (test after 360 h drying cycle and then 240 h wet cycle or another 240 h according to DIN 75 220), values of> 4N / 5cm and <15 N / 5 cm are achieved.

However, the automotive industry is placing ever increasing demands on the adhesion between the plastic layer and the polyurethane layer, so that it is desirable to achieve higher adhesion values, in particular higher values in the roller peeling test according to PV 2034 and in the separation test according to DIN 53 357 A. Even slight changes in the production parameters can lead to large fluctuations in the roller skiving experiments.

The object of the invention was to provide composite elements which can be used, for example, in automobile construction because of their excellent mechanical properties and in which the adhesion between the plastic and the polyisocyanate polyaddition products adhering thereto is very good, so that in the roller peel test or in the separation test values> 20N / 5cm can be achieved. In particular, the composite elements with starting components should be produced, which give crystallization-stable mixtures even at temperatures <0 ⁰ C and thus can be used easily and reproducibly even at low temperatures.

The invention relates to composite elements containing as a layer

A) A plastic adhering to it as a layer

B) the product is followed by the reaction of a reaction mixture containing

a) a mixture having an isocyanate content of 20 to 30 wt .-% of carbodiimide (CD) uretonimine (UI) groups having Isocyanatprepolymeren and optionally polymeric MDI

b) isocyanate-reactive compounds

c) optionally catalysts - - d) optionally propellant

e) optionally auxiliaries and / or additives.

The modified isocyanate prepolymer is obtainable from at least one isocyanate containing carbodiimide (CD) uretonimine (UI) groups and a polyol and / or a chain extender. This prepolymer may preferably be blended with polymeric diphenylmethane diisocyanate (MDI). The mixture has an isocyanate group content of 20 to 30%.

The use of CD / UI group-containing isocyanate prepolymers for the production of solid polyurethanes or polyurethane foams, the adhesion between the polyurethane (PUR) and the thermoplastic is surprisingly significantly improved, even after aging. In addition, the prepolymers used have an excellent

Low temperature stability on.

Carbodiimide-modified isocyanates are known per se and e.g. in WO 2007/006622 and in GB 2 268 180. Prepolymers based on carbodiimide-modified isocyanates are also known and e.g. in WO 2002/048231 and WO 2006/069624.

The composite elements according to the invention may comprise as plastic (A) Polyurethanansprühhäute or conventional thermoplastics, such as polyphenylene oxide (PPO), polyvinyl chloride (PVC), acrylonitrile-butadiene-styrene acrylic ester (ASA), polycarbonate (PC), thermoplastic polyurethane (TPU), polyethylene (PE), polypropylene (PP), styrene-maleic anhydride (SMA), polycarbonate / styrene-acrylonitrile / acrylonitrile-butadiene blend (PC / ABS) and blends thereof.

The plastics (A) can be used for example in the form of films for the production of the composite elements. Preferably, the films have a thickness of 0.2 to 2 mm. Preference is given to using polyvinyl chloride (PVC) or polyurethane skin care as the plastic (A).

Such films are commercially available and their preparation is well known.

The composite elements can preferably be used as a stiffening part for instrument panels or door side parts.

Preferred as product (B) [polyisocyanate polyaddition product] are polyurethanes which may be present in a compact or preferably cellular form, for example as flexible foam, semi-rigid foam or rigid foam, particularly preferably as semi-rigid foam.

The products (B) are preferably obtainable from the following starting compounds: - - a) a mixture having an isocyanate content of 20 to 30 wt .-% of carbodiimide / uretonimine having Isocyanatprepolymeren and optionally polymeric MDI

b) isocyanate-reactive compounds

c) optionally catalysts

d) optionally propellants

e) optionally auxiliaries and / or additives.

The components a) to e) are described in more detail below:

The prepolymers under (a) are preferably from

i) aromatic isocyanates, such as. B. polyisocyanates based on 4,4'-, 2,4'- unάV- or 2,2'-diphenylmethane diisocyanate and any mixtures thereof, which are modified with carbodiimide AJretonimingruppen and

ii) generally known isocyanate-reactive compounds, for example polyetherpolyalcohols, polyesterpolyalcohols and / or polycarboxylate diols having molecular weights of between 500 and 12,000 and functionalities of 2 to 6 and / or

Chain extenders and / or crosslinking agents having molecular weights of 60 to 499 and functionalities of 2 to 6, preferably 2, obtained.

The mixture a) may optionally contain polymeric MDI. The polymeric MDI used are preferably crude polymer-MDI mixtures, as obtained in the phosgenation of crude diphenylmethanediamine. Crude polymer-MDI mixtures, as obtained in the phosgenation of crude Diphenylrnethanediamine, preferably still have a proportion of monomeric MDI from 20 to 60 wt .-% and have a viscosity of 1200 mPas / 20 ° C to 100 mPas / 20 ° C (the monomeric MDI is present as a mixture of 4,4'-, 2,4'- and 2,2'-di-phenylmethane diisocyanate).

As component (b) it is possible to use generally known isocyanate-reactive compounds, for example polyetherpolyalcohols, polyesterpolyalcohols and / or polycarbonatediols, preferably polyetherpolyols and / or polyesterpolyalcohols, preferably having a molecular weight of from 500 to 10,000, in particular from 1,000 to 6,000, and having one Functionality of 2 to 6. Optionally, filled polyether polyols, such as styrene-acrylonitrile (SAN) - - or polyurea (PHD) - or polyisocyanate polyaddition (PIPA) -Polyetheφθlyole be used. The compounds (b) can also be used in admixture with chain extenders and / or crosslinking agents. The chain extenders are preferably bifunctional alcohols having molecular weights of from 60 to 499, for example ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol. The crosslinking agents are preferably compounds having molecular weights of from 60 to 499 and functionalities of from 3 to 6, preferably amines and more preferably alcohols, for example glycerol, trimethylolpropane and pentaerythritol. The chain extenders and / or crosslinkers may also be used alone as component (b).

As catalysts (c) conventional compounds can be used, for example, the

Rapidly accelerate the reaction of component (a) with component (b). For example, tertiary amines generally known for this purpose and / or organic metal compounds, in particular tin compounds, are suitable. The catalysts used are preferably those which have the lowest possible emission (for example VOC and FOG values in VDA278 test and fogging values according to DIN 75201), ie. to the lowest possible release of volatile

Compounds of the reaction product (B), for example, potassium acetate and / or Li salts and / or tertiary amines having at least one hydroxyl functional group and / or reactive polymer catalysts such. in DE-A 100 56 309 and EP-A 0 696 580.

Suitable blowing agents (d) for the production of foamed products (B), for example polyurea soft, semi-hard or rigid foams, which may optionally have urea and / or isocyanurate structures, are generally known chemically or physically active compounds , As a chemically acting blowing agent it is also possible with preference to use water which forms carbon dioxide by reaction with the isocyanate groups. Examples of physical blowing agents, i. inert compounds which evaporate under the conditions of polyurethane formation are (cyclo) aliphatic hydrocarbons, preferably those having 4 to 8, more preferably 4 to 6 and in particular 5 carbon atoms, partially halogenated hydrocarbons or ethers, ketones or acetates. The amount of blowing agent used depends on the desired density of the foams. The different blowing agents can be used individually or in any mixtures with each other.

The reaction may optionally be carried out in the presence of (e) auxiliaries and / or additives, such as adhesion promoters, fillers, fibers (eg in the form of fabrics and / or mats), cell regulators, surface-active compounds, stabilizers against oxidation, thermal or microbial degradation or aging and chain breakers. Another object of the invention is a method for producing the composite elements according to the invention, wherein

a) a mixture having an isocyanate content of 20 to 30 wt .-% of CD-AJI-modified isocyanate prepolymers and optionally polymeric MDI with

b) isocyanate-reactive compounds

c) in the presence of optionally catalysts

d) optionally propellants

e) optionally auxiliaries and / or additives

in the presence of (A) a plastic is reacted.

For the preparation of the products (B), the mixture (a) and the isocyanate-reactive compounds (b) are preferably reacted in amounts such that the equivalence ratio of NCO groups from (a) to the sum of the reactive hydrogen atoms from (b ) and optionally from (d) 0.3: 1 to 1.8: 1, more preferably 0.4: 1 to 1.0: 1 and in particular 0.4: 1 to 0.6: 1, is. If the product (B) at least partially contains isocyanurate groups, is preferably a ratio of NCO groups to the sum of the reactive

Hydrogen atoms of 1.5: 1 to 60: 1, preferably 1.5: 1 to 8: 1, adjusted.

The conversion to the product (B) can be carried out, for example, by hand casting, by high-pressure or low-pressure machines or by the RIM process (reaction injection molding) usually in open or preferably closed molds. Suitable processing machines are commercially available.

The starting components a) to e) are usually mixed at a temperature of 0 to 100 ⁰ C, preferably from 20 to 80 ⁰ C, and introduced, for example, in a mold. The mixing can be carried out mechanically by means of a stirrer or carried out in a conventional high-pressure mixing head.

The reaction of the reaction mixture can be carried out, for example, in customary, preferably heatable and sealable forms.

Conventional and commercially available tools whose surface consists for example of steel, aluminum, enamel, Teflon, epoxy resin or another polymeric material may be used as molding tools for producing the composite elements, the surface optionally being chrome-plated, for example hard chromium-plated. Preferably, the molds - - To be able to be tempered in order to set the preferred temperatures, and be closed.

The starting components are preferably used at a temperature of 20 to 50 ⁰ C. The reaction to the products is usually carried out at a mold temperature of 20 to 120 ⁰ C, preferably 25 to 100 ⁰ C, particularly preferably 30 to 80 ⁰ C, for a period of usually 0.5 to 30 minutes, preferably 1 to 5 min. The reaction in the mold takes place in accordance with Erftndungs in direct contact with (A). This can be achieved, for example, by placing a plastic (A) as a decorative skin and optionally additionally a support before reacting the reaction mixture in the mold and then adding the reaction mixture to the mold. The production of composite elements can be either open or closed

Filling done. Any fibers used as component (e) may be used both in the reaction mixture and in the form of mats or fabrics. If mats or fabrics are used as component (e), they may, for example, be applied to the film (A) present in the mold before the reaction mixture is introduced, and then the reaction mixture, which in this case preferably contains no additional fibers, can be applied the mold will be filled.

The composite elements of the invention have a significantly improved adhesion between (A) and (B) by the use of the mixture (a), which also has a high low-temperature stability. In the separation test according to DIN 53 357 A and in the roller peel test in accordance with PV 2034, the composite elements according to the invention have values above aging of more than 20 N / 5 cm.

Another object of the invention are isocyanate mixtures having an isocyanate content of 20 to 30 wt .-% of carbodiimide / uretonimine-modified Isocyanatprepolymeren and optionally polymeric MDI.

The composite elements according to the invention are preferably used as components in vehicle, aircraft or real estate construction, for example as dashboards, door panels, hat racks, consoles, armrests or door mirrors.

The invention will be explained in more detail with reference to the following examples. Description of the starting materials

isocyanates:

Isocyanate 1:

100 wt. Parts of Desmodur ^® CD-S from Bayer MaterialScience AG (partially carbo- diimidiertes diphenylmethane-4,4'-diisocyanate with an NCO content of 29.5%)

100 wt. Parts of Desmodur ^® 90/10 from Bayer MaterialScience AG (mixture of diphenylmethane-4,4'-diisocyanate with 2,4'- and 2,2'-MDI and homologues having an isocyanate content of 32.6% ) and

49.97 parts by weight of a polyether having an average molecular weight of 12000 g / mol, prepared by addition of propylene oxide / ethylene oxide (82/18) to sorbitol as a starter, were reacted at 80 ° C for three hours. The resulting NCO prepolymer was then mixed with 52.49 parts by weight of Desmodur ^® 44V 10 L of Bayer MaterialScience AG (polymeric MDI having an NCO content of 31.5%).

There was obtained a mixture with an NCO content of 25.5 wt .-% and a viscosity of 190 mPa s @ 25 ° C. The mixture is at least a week stable to crystallization at -10 ^0C.

Isocyanate 2:

Mixture of 60 parts by weight of Desmodur ^® 90/10 (Bayer MaterialScience AG) and 40 parts by weight of Desmodur ^® 44V20 LF (Bayer MaterialScience AG; polymeric MDI having an NCO content of 31.5%) having an NCO Content of the mixture of 32.4 wt .-%.

Isocyanate 3:

A prepolymer having an NCO content of 25.6 wt .-% of 82.5 parts by weight of Desmodur ^® CD-S from Bayer Material Science AG and 17.5 parts by weight of a polyether having an average molecular weight of 12,000 g / mol, prepared by addition of propylene oxide / ethylene oxide (82/18) to sorbitol as a starter. - -

Isocyanate 4:

A prepolymer having an NCO content of 25.4 wt .-% of 63.93 parts by weight of Desmodur ^® 90/10 from Bayer MaterialScience AG, 16.00 parts by weight of Desmodur ^® 44V10L of Bayer Material Science AG and 20, 07 parts by weight of a polyether having an average molecular weight of 12000 g / mol, prepared by addition of propylene oxide / ethylene oxide (82/18) to sorbitol as a starter.

polyols:

Polyol I: Polyether polyol having an average molecular weight of 6000 g / mol prepared by addition of propylene oxide / ethylene oxide (83/17) to glycerol as a starter and having a polyurea filler content of 20 wt .-%.

Polyol 2: Polyether polyol having an average molecular weight of 4800 g / mol prepared by addition of propylene oxide / ethylene oxide (83/17) to glycerol as a starter.

Polyol 3: Polyether polyol having an average molecular weight of 6235 g / mol prepared by addition of propylene oxide / ethylene oxide (78/22) to glycerol as a starter.

Polyol 4: Polyether polyol having an average molecular weight of 6000 g / mol and at least 80% of primary OH groups, prepared by addition of propylene / ethylene oxide (82/18) to glycerol as starter and having a grafted filler content of 20% by weight. of styrene / acrylonitrile (40% / 60%).

chain:

Chain extender 1: Polyether polyol having a molecular weight of 356 g / mol and a functionality of 4 prepared by propylenoxylation with ethylenediamine.

Chain extender 2: diethanolamine

catalysts:

Catalyst 1: Dabco ^® NE 1070 from Air Products (dimethylaminopropyl about 60% strength (in diethylene glycol gel catalyst))

Catalyst 2:. Jeffcat ZF ^® 10 from the company Huntsman (N, N, N'-trimethyl-N'-hydroxyethyl-bis-aminoethyl ether (blowing catalyst,)) - -

Catalyst 3: Desmorapid 59EF05 ^® from Bayer MaterialScience AG (poly (oxyalkylene) - amine catalyst

additives:

Additive 1: black paste N from Fa. ISL Chemie (black paste based on carbon black)

Additive 2: Ethacure 100 ^® LC Fa of Albemarle (diethyltoluylenediamine-80).

Additive 3: Tegostab B8715 LF from Evonik (silicone stabilizer)

Foaming:

With the starting compounds shown in Table 1 polyurethane molded foams were prepared. For this purpose, the polyols, water, activators and other additives were mixed into a polyol formulation. Then, the polyol formulation with the isocyanate component was homogenized in a high-pressure mixing head and poured into a mold with a temperature of 40 ⁰ C. The mold already contained a PVC decorative film (type DSY 260/02 from Resinoplast) and a support made of polypropylene. For the determination of the mechanical properties, additional plates with a size of 200 * 200 * 40 mm were produced. For the determination of the composite properties to the decorative layer were also plates with a size of

200 * 200 * 20 mm made. In the latter case, a PVC decorative film was previously placed in the mold.

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The quantities in Table 1 are parts by weight.

Table 1:

The results in Table 1 show that in Examples 1 and 3 according to the invention in comparison with Example 2 and in Examples 4 and 5 according to the invention in comparison with Example 6, the polyurethane adheres better to the decorative film. Values in the separation test of more than 20 N / 5 cm are achieved.

Claims

- Patent claims

1. composite elements containing as a layer

A) A plastic adhering to it as a layer

B) the product is followed by the reaction of a reaction mixture containing

a) a mixture having an isocyanate content of 20 to 30 wt .-% of

Carbodiimide / uretonimine containing isocyanate prepolymers and optionally polymeric MDI

b) isocyanate-reactive compounds

c) optionally catalysts

d) optionally propellant

e) optionally auxiliaries and / or additives.

2. A process for the production of composite elements according to claim 1, wherein

a) a mixture having an isocyanate content of 20 to 30 wt .-% of carbodiimide-AJretonimin-modified Isocyanatprepolymeren and, optionally, polymeric MDI with

b) isocyanate-reactive compounds

c) in the presence of optionally catalysts

d) optionally propellants

e) optionally auxiliaries and / or additives

in the presence of (A) a plastic is reacted.

3. Isocyanate mixtures having an isocyanate content of 20 to 30 wt .-% of carbodiimide / uretonimine-modified isocyanate prepolymers and optionally polymeric MDI.

4. Use of the composite elements according to claim 1 for the production of components in vehicle, aircraft and real estate.