EP3931233A1

EP3931233A1 - Two or multi-layer structures and method for the production thereof

Info

Publication number: EP3931233A1
Application number: EP20705208.5A
Authority: EP
Inventors: Bert Klesczewski; Hans-Detlef Arntz; Christos Karafilidis
Original assignee: Covestro Intellectual Property GmbH and Co KG
Current assignee: Covestro Intellectual Property GmbH and Co KG
Priority date: 2019-02-26
Filing date: 2020-02-19
Publication date: 2022-01-05
Also published as: WO2020173784A1

Abstract

The invention relates to two or multi-layer structures for automotive interiors and engine compartments, to a method for producing the same and to the use thereof.

Description

Two- or multi-layer structures and processes for their production

The present invention relates to two- or multi-layer structures for automotive interiors and a method for their production.

WO 2013/168185 describes the use of MDI prepolymer components, based on polyol components with a nominal functionality of 1 to 2, as an adhesive for multilayer structures, in particular car headliners.

WO 2002/48232 describes prepolymers as wood adhesives with an NCO content of 8-20% by weight, which are produced on the basis of organic polyisocyanates and dispersions of reaction products of polyamines or hydrazine or hydrazine derivatives with isocyanate in polyether polyol.

In WO 2010/139708 composite components that are used as headliners are written that have plastically deformable rigid polyurethane foams, adhesive and a cover material. The multi-layer structure contains glass fiber mats, a polyurethane foam with a bulk density of 27.8 kg / m ³ and a moisture-curing polyurethane adhesive between the polyurethane foam and the glass fiber mats.

DE 102008025005 uses nanourea particles as additives to reduce emissions of volatile organic substances in polyurethane foams and to improve the fire behavior of the foams. Disadvantages of this process are the complex preparation of the polyols containing nanourea particles and their high viscosity.

Interior components for vehicles are extensively described in the literature. In particular, publications relating to topics such as thermal insulation and acoustic absorption with simultaneous high demands on mechanical properties are taking up more and more space.

The steadily increasing demands made on the emission behavior of such roof liners produced in a multi-layer structure, in particular with regard to the emitted concentrations of aldehydes such as formaldehyde and acetaldehyde, represent a considerable problem.

The object of the present invention was to reduce the emissions from the parts installed in the interior of vehicles, in particular the emissions of aldehydes such as formaldehyde and acetaldehyde.

This object could be achieved by a two- or multi-layer structure as described in more detail in claim 1.

The invention relates to a two- or multi-layer structure A) optionally one or more decorative layers,

B) one or more glass fiber layers,

C) a polyurethane foam layer, which is arranged between B) and D) if available, with a bulk density of 18 to 40 kg / m ^{3 in} accordance with DIN 53420,

D) optionally one or more glass fiber layers,

E) optionally one or more top layers,

characterized in that the polyurethane foam layer C) is impregnated with F) a reaction product of water and / or atmospheric humidity and NCO prepolymers Fl) with an NCO content of> 25% by weight to 30% by weight, optionally in the presence of catalysts , the NCO prepolymers F1) being a reaction product of a) polymeric diphenylmethane diisocyanate (MDI) with an NCO content of 30 to 33.5% by weight and

b) at least one organic polyhydroxyl compound in the form of a dispersion containing reaction products

bl) tolylene diisocyanate (TDI) with

b2) polyamines containing primary and / or secondary amino groups and / or hydrazine and / or hydrazides in one

b3) polyether polyol containing at least two hydroxyl groups and a number average molecular weight of 1000 to 12000 mol / g

c) optionally in the presence of one or more catalysts.

Another object of the invention is a method for producing the two- or multi-layer structure according to the invention, wherein

i) the polyurethane foam layer C) is presented,

ii) the layer C) is impregnated with the NCO prepolymers F1),

iii) at least one or more glass fiber layers B) or D) are applied to at least one of the two sides of the impregnated layer C), iv) then optionally the one or more cover layers E) on the polyurethane foam layer C) or the glass fiber layer D) - so far present - and optionally the one or more decorative layers A) are applied to the glass fiber layer B) so that a layer composite is formed, v) water and, if appropriate, catalyst are added to the layer composite or the layer composite is exposed to air humidity,

vi) the layer composite is placed in a heated mold, the layer composite being pressed and shaped and the NCO prepolymers F1) hardening with the added water or atmospheric humidity, vii) the molded, pressed and cured two- or multi-layer structure is removed from the mold.

The two- or multi-layer structure according to the invention is preferably used for headliners in automobile interiors.

Preferred embodiments of the two- or multi-layer structure are:

Layer C) with one or more layers B) and one or more layers D)

Layer C) with one or more layers B) and one or more layers A)

Layer C) with one or more layers B) and one or more layers E)

Layer C) with one or more layers B) and one or more layers D) and one or more layers A)

Layer C) with one or more layers B) and one or more layers D) and one or more layers E)

Layer C) with one or more layers B) and one or more layers A) and one or more layers E)

Layer C) with one or more layers A) and one or more layers B) and one or more layers D) and one or more layers E)

The isocyanate-terminated prepolymer F1) has an NCO content of 25 to 30% by weight.

The reaction products b) preferably used according to the invention are polyureas and / or polyhydrazodicarbonamides, their content preferably not falling below 2, particularly preferably 5% by weight in the isocyanate-terminated prepolymer F1). Their proportion is preferably between 2 and 25, particularly preferably between 5 and 15% by weight, based on the total amount of NCO prepolymer.

Suitable diisocyanates bl) for the preparation of the dispersed polyaddition products are e.g. 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene and their isomer mixtures. The mixture of 2,4- and 2,6-diisocyanatotoluene in a ratio of 80 to 20 is preferred.

Suitable structural components with isocyanate-reactive groups b2) are, for example, divalent and / or polyvalent, primary and / or secondary aliphatic, araliphatic, cycloaliphatic and aromatic polyamines, such as, for example, ethylenediamine, hexamethylenediamine, trimethyldiaminohexane, N, N'-dimethylenediamine, higher homologues of ethylenediamine, such as diethylenetriamine, homologues of propylenediamine, such as dipropylenetriamine, piperazine, triazine, 4-aminobenzylamine, 4,4'-diaminodicyclohexylmethane and propane, 1,4-diamino-cyclohexane, phenylenediamines, condensates of aniline and formaldehyde, and toluylene -aminomethylbenzenes. Hydrazine and mono- or N, N'-disubstituted hydrazines and hydrazides, such as hydrazides of di- or polybasic carboxylic acids. Hydrazine hydrate is preferred.

Suitable polyether polyols b3) containing at least two hydroxyl groups are polyadducts of propylene oxide and / or ethylene oxide with bifunctional and trifunctional starters or mixtures thereof such as, for example, water, 1,2-propylene glycol, trimethylolpropane, glycerol, pentaerythritol or other polyhydroxyl compounds, such as, for example, based on polyether polyols of tetrahydrofuran (polytetramethylene ether glycol) or natural oils containing hydroxyl groups (e.g. castor oil). Any desired mixtures of such polyhydroxyl compounds can of course also be used.

The solids content of the dispersion b) of polyureas and / or polyhydrazodicarbonamides in polyethers containing hydroxyl groups is preferably between 5 and 40% by weight, particularly preferably between 10 and 25% by weight.

The sedimentation-stable, finely divided polyurea and / or polyhydrazodicarbonamide particles introduced as dispersions in polyethers containing hydroxyl groups have a size of 0.01 to 10, preferably 0.01 to 1 μm. The viscosities of such filler-containing polyols are less than 10,000, preferably less than 3000, mPa * s at 25 ° C. and a solids content of 20% by weight.

The dispersion b) used preferably contains the reaction products from

16.9 parts by weight of a mixture of 2,4- and 2,6-diisocyanatotoluene bl) in a ratio of 80 to 20 with 4.85 parts by weight of hydrazine hydrate b2) in 80 parts by weight of a polypropylene ether polyol b3) with a functionality greater than 2 and an ethoxyethylene group content of 0 to 30, preferably 5 to 20% by weight and a hydroxyl number of 20 to 56, preferably 30 to 40 mgKOH / g.

The above-described filled polypropylene ether polyol is e.g. sold by Covestro Deutschland AG in Feverkusen under the trade name Baycoll® BT 5028.

To build up the isocyanate-terminated prepolymers F1), use is made of polyisocyanates such as those obtained by phosgenation of aniline / formaldehyde condensates, which are known as polymer MDI (P-MDI) and a mixture of the monomeric 2,2'- and 2 Represent, 4'- and 4,4'-diphenylmethane diisocyanates with higher oligomers (polydiphenylmethane polyisocyanates).

To produce the NCO prepolymer F1), the polymer dispersion b) is reacted with the organic polyisocyanate MDI (a).

In the preparation of the NCO prepolymer F1) there are preferably 3 to 30, more preferably 5 to 20, isocyanate groups for each isocyanate-reactive group. The proportion of polyol component b) in the finished NCO prepolymer is preferably between 20 and 75 % By weight, particularly preferably between 30 to 60% by weight. The proportion of

Polyisocyanate component a) is preferably between 80 to 25% by weight, particularly preferably between 70 to 40% by weight.

To prepare the prepolymers, the excess component, the polyisocyanate a), is generally placed in the kettle at temperatures of 50 to 70.degree. C. and the polyol component b) is added in such a way that the kettle temperature does not rise above 80.degree. In principle, it is also possible to mix the polyisocyanates a) and the polyols b) intensively with one another using a mixing unit (e.g. a static mixer or dynamic mixer or high-pressure nozzles) and cause them to react.

Preferred prepolymers F1) are made with organic polyisocyanates a) with a proportion of 0 to 60, preferably 5 to 40% by weight of difunctional 2,4'-MDI and a proportion of higher oligomers with functionality greater than 2 from 0 to 50, preferably 0 to 40% by weight.

In principle, there is either the possibility of producing the NCO prepolymers F1)

(I) to directly use an organic polyisocyanate containing 2,4'-MDI a) with an oligomeric fraction of 20 to 60% by weight (P-MDI) or

(II) first of all to carry out the reaction with a pure diisocyanate which contains a 2,4'-MDI content of 40 to 60% by weight, up to an NCO content of 8 to 11% by weight, and then a P-MDI with an oligomeric fraction of up to 70% by weight, so that an NCO content of 25 to 30% by weight is established in the mixture.

The prepolymer produced according to (II) has a lower viscosity than the prepolymer which is obtained according to (I).

The NCO prepolymers produced in this way preferably have viscosities of 200-40,000 mPa * s at 25 ° C.

Furthermore, for example, the use of up to 20 parts by weight of amine-started polypropylene / ethylene ether glycols in component b) can be advantageous since they give the prepolymers an accelerated reaction with atmospheric moisture. Mention should be made here in particular of ethylene diamine or ammonia-started polypropylene ether polyols with an OH number of 40 to 200 mgKOH / g. Such an accelerated reaction with atmospheric moisture can of course also be carried out with the common catalysts c) customary in polyurethane chemistry, for example tertiary amines such as diazabicycloctane, dimorpholinodiethyl ether or metal catalysts such as dibutyltin dilaurate in amounts of 0.005 to 0.5% by weight, based on prepolymer can be achieved.

The prepolymers F1) can also be provided with the usual additives, such as, for example, thickeners, for example aerosils which have been hydrophobized on the surface, short fibers such as Kevlar pulp or similar microfibers for thixotropic effects. It can continue to be modified if necessary, further additives can be added, such as natural or synthetic resins, pigments or anti-aging agents.

The two- or multi-layer structures according to the invention are preferably used as components in the interior of an automobile (for example as a headliner) and in the automobile engine compartment (for example as a sound absorber).

Sample part:

Materials used:

Isocyanate a): polymeric MDI with an isocyanate content of 31.5% available as Desmodur® 44V20 L from Covestro Deutschland AG, Leverkusen

Dispersion b): 20% dispersion of a reaction product of hydrazine and tolylene diisocyanate in a polyether polyol with a hydroxyl number of 35 mg / g KOH based on EO / PO, starter: glycerine, available as Baycoll® 5028 GT from Covestro Deutschland AG, Leverkusen

Catalyst: solution of a mixture of 10 wt .-% dimethylaminoethanolamine and 90 wt .-%

water

Procedure implementation:

1) Production of the NCO prepolymer Fl):

1425 g of a polymethylene polyphenylene isocyanate (trade name Desmodur® 44V20 L, Covestro Deutschland AG, Leverkusen) are placed under a dry nitrogen atmosphere and heated to 75.degree. Then 75 g of Baycoll® 5028 GT (Covestro Deutschland AG, Leverkusen, a 20% dispersion of a reaction product of hydrazine and tolylene diisocyanate in a polyether polyol with a hydroxyl number of 35 mg / g KOH based on EO / PO, starter: glycerine) are used as a component b) added and stirred at 80 ° C. for 2 hours.

The prepolymer (F1) obtained in this way had the following characteristics:

NCO content: 29.0% by weight

Viscosity at 25 ° C: 400 mPa * s

2) Making the polyurethane foam layer:

The polyurethane foam layer was produced in the form of a polyurethane foam sheet (in the format 300 mm x 300 mm x 12 mm) according to comparative example 1 from WO2014 / 153701:

A mix of

31.0 parts by weight of a polyether alcohol based on glycerol / propylene oxide / ethylene oxide, OH number 28 mg KOH / g, functionality 3,

35.05 parts by weight of a polyether alcohol based on trimethylolpropane / propylene oxide, OH number 550 mg KOH / g, functionality 3, 12.0 parts by weight of a polyether alcohol based on propylene glycol / propylene oxide, OH number 512 mg KOH / g, functionality 2,

15.0 parts by weight of a reaction product of phthalic anhydride, diethylene glycol and ethylene oxide, OH number 300 mg KOH / g, functionality 2,

0.50 parts by weight of l, l ’- ((3- (dimethylamino) propyl) imino) bis-2-propanol and 0.05 parts by weight of bis (2-dimethylaminoethyl) ether,

0.20 parts by weight of a silicone foam stabilizer (Niax® Silicone SR 234 from Momentive Performance Materials),

5.80 parts by weight of water and

0.50 parts by weight of Isopur N black paste from ISL-Chemie. Kürten, Germany

were mixed with

175 parts by weight of a mixture of diphenylmethane diisocyanates and polyphenylpolymethylene polyisocyanates, which has a diphenylmethane diisocyanate isomer content of 60% by weight and an NCO content of 31.8% by weight. This mixture contains 13.9% by weight, based on the total organic polyisocyanate component, of 2,4'-diphenylmethane diisocyanate and 44.7% by weight, based on the total organic polyisocyanate component, of 4,4'-diphenylmethane diisocyanate.

3) A) Production of the impregnated polyurethane foam layer C):

The sheet of foam was sprayed on one side first with 18 g of the respective NCO prepolymer F1) and then with 2 g of the catalyst. The sprayed side of the foam board was then covered with paper (format 300 mm × 300 mm). After a reaction time of five minutes, the foam sheet was placed between two aluminum sheets heated to 120 ° C. for one minute. After a cooling time of ten minutes, the procedure was repeated on the second side of the foam sheet.

3) B) Comparative example with MDI instead of the prepolymer Fl

The foam board was sprayed on one side first with 17 g of MDI and then with 2 g of the catalyst. The sprayed side of the foam board was then covered with paper (format 300 mm × 300 mm). After a reaction time of five minutes, the foam sheet was placed between two aluminum sheets heated to 120 ° C. for one minute. After a cooling time of ten minutes, the procedure was repeated on the second side of the foam sheet. Table:

Claims

Patent claims:

1. Containing two- or multi-layer structure

A) optionally one or more decorative layers,

B) one or more glass fiber layers,

C) a polyurethane foam layer, which, if D) is present, is arranged between B) and D), with a bulk density of 18 to 40 kg / m ³ according to DIN 53420,

D) optionally one or more glass fiber layers

E) optionally one or more top layers,

characterized in that the polyurethane foam layer C) is impregnated with F) a reaction product of water and / or atmospheric humidity and NCO prepolymers Fl) with an NCO content of> 25% by weight to 30% by weight, optionally in the presence of catalysts , the NCO prepolymers F1) being a reaction product from

a) polymeric diphenylmethane diisocyanate (pMDI) with an NCO content of 30 to 33.5% by weight and

bl) tolylene diisocyanate (TDI) with

c) optionally in the presence of one or more catalysts.

2. Two- or multi-layer structure according to claim 1 containing, in addition to layer C) and layer B), a layer A) in the form of one or more decorative layers.

3. A method for producing the two- or multi-layer structure according to claim 1 or 2, wherein

i) the polyurethane foam layer C) is presented,

ii) the layer C) is impregnated with the NCO prepolymers F1),

iii) at least one or more glass fiber layers B) or D) are applied to at least one of the two sides of the impregnated layer C), iv) then optionally the one or more cover layers E) on the polyurethane foam layer C) or the glass fiber layer D) - so far present - and optionally the one or more decorative layers A) are applied to the glass fiber layer B) so that a layer composite is created, v) Water and, if applicable, catalyst are added to the layer composite or the layer composite is exposed to air humidity

vi) the layer composite is placed in a heated mold, the layer composite being pressed and shaped and the NCO prepolymers F1) hardening with the added water or the humidity,

vii) the molded, pressed and cured two- or multi-layer structure is removed from the mold.

4. Use of the two- or multi-layer structure as a component in the automobile interior and engine compartment.