CA3184310A1

CA3184310A1 - Novel phthalate-free isocyanurate composition and use thereof

Info

Publication number: CA3184310A1
Application number: CA3184310A
Authority: CA
Inventors: Thomas Augustin; Ian LOCHRIE
Original assignee: Lanxess Deutschland GmbH
Current assignee: Lanxess Deutschland GmbH
Priority date: 2020-05-28
Filing date: 2021-05-21
Publication date: 2021-12-02
Also published as: EP3916031A1; JP2023527052A; CO2022017024A2; EP4157908A1; EP4157908B1; BR112022024190A2; CN115698112A; AR122174A1; IL298513A; ZA202213888B; WO2021239621A1

Abstract

The present invention relates to new low-monomer, low-viscosity, low-volatility compositions of isocyanate group-containing isocyanurates and a phthalate-free plasticizer, which, when used as adhesion promoters, result in improved adhesion, to coating agents on the basis of plasticized PVC and to coated substrates.

Description

Novel phthalate-free isocyanurate composition and use thereof The present invention relates to the technical field of adhesion promoters, in particular of adhesion promoters for coating compositions based on plasticized PVC, and provides phthalate-free, low-monomer-content, low-viscosity and low-volatility compositions which have excellent suitability as adhesion promoters.
Prior art It is known that the capability of plasticized PVC to adhere on substrates can be improved by adding to the plasticized PVC an adhesion promoter comprising isocyanate groups. Adhesion capability thus improved is important by way of example when the intention is to produce synthetic textile materials provided with a PVC covering. Adhesion promoters used are preferably isocyanurates which comprise isocyanate groups and which can be produced from diisocyanates by oligomerization, in particular trimerization. Diisocyanates used for this purpose are (TDI) normally mixtures of isomeric diisocyanatotoluenes consisting mainly of 2,4-diisocyanatotoluene (2,4-TDI) and 2,6-diisocyanatotoluene (2,6-TDI), these mixtures being readily available commercially. These can easily be converted almost entirely to isocyanurates comprising isocyanate groups. The almost complete conversion is necessary for reasons of workplace safety and product safety, and EU regulation, and for these reasons the residual content of diisocyanates in the adhesion promoter composition is kept below 0.5% by weight.
Less suitable are diisocyanatodiphenylmethanes (MDI), which likewise have good availability, but give poorer trimerization than TDI and therefore can lead to an undesirable high residual content of diisocyanates. MDI-based isocyanurates comprising isocyanate groups moreover exhibit poor solubility and have a tendency towards crystallization.
lsocyanurates comprising isocyanate groups Isocyanurates comprising isocyanate groups provide easy handling as adhesion promoters especially when they are used in the form of a solution in a plasticizer. TDI-derived isocyanurates comprising isocyanate groups are preferably produced within the plasticizer used as solvent. These adhesion promoters, and adhesion promoter compositions comprising plasticizer, production thereof and use thereof are described by way of example in DE2419016 Al (GB1455701 A) or in W02011/095569.
Plasticizer and plasticized PVC
For the purposes of the present invention, plasticizers are typically organic substances which have no volatility or only low volatility and which do not enter into covalent bonding with PVC, but lower its glass transition temperature. Mixing with the plasticizer converts the PVC, which Date Recue/Date Received 2022-11-21

- 2 -per se is hard and brittle, to a material that is flexible and tough, which the person skilled in the art calls plasticized PVC or flexible PVC. At room temperature, the plasticized PVC is usually a flexible solid. Suitable plasticizers are known to the person skilled in the art. Examples of typical plasticizers are esters of phthalic acid, terephthalic acid, sebacic acid, trimellitic acid, alkanesulphonic acid, citric acid or benzoic acid with alcohols. Quantities of such plasticizers present in plasticized PVC are significant, usually being in the range of 10%
by weight to more than 50% by weight of the total mass of the plasticized PVC. Under unfavourable usage conditions, the plasticizer can migrate to the surface or into adjacent materials. The use of plasticized PVC therefore brings the risk of contamination of people and environment by the plasticizer. In the light of these problems, the plasticizers used have in recent years been subject to increasing demands that they cause no harm to humans and are not bioaccumulative.
Short-chain phthalates as plasticizers The REACH regulation applicable in the European Union places the plasticizers di(2-ethylhexyl) phthalate, dibutyl phthalate and benzyl butyl phthalate on the SVHC (Substances of Very High Concern) list. Furthermore, the plasticizers diisononyl phthalate, diisodecyl phthalate and di-n-octyl phthalate can no longer be used in toys or baby items that children could place in their mouths. In view of these restrictions, which some consumers could regard as unclear and worrying, many producers are generally moving towards avoidance of all phthalate-containing plasticizers and their isomers in the production of plasticized PVC. There is accordingly a demand for phthalate-free plasticizers which achieve the performance level of phthalate-based plasticizers in respect of processability and usage properties.
Phthalate-free plasticizers In the context of the present invention, the expression "phthalate-free plasticizers" is used for plasticizers comprising ¨ based on the content of plasticizer¨ less than 1.0%
by weight, preferably less than 0.5% by weight, particularly preferably less than 0.1% by weight and particularly preferably 0% by weight, of dialkyl phthalates.
Phthalate-free adhesion promoter compositions Avoidance of phthalate-containing plasticizers is now also required of adhesion promoter compositions which comprise plasticizers, in particular for sensitive applications involving, for example, skin contact. There is therefore high demand for adhesion promoter compositions which comprise no phthalates but which nevertheless have the good adhesion properties of phthalate-containing adhesion promoter compositions from the prior art. In the context of the present invention, the expression "phthalate-free adhesion promoter compositions" is used for Date Recue/Date Received 2022-11-21

- 3 -adhesion promoter compositions which ¨ based on their total mass ¨ comprise less than 1.0%
by weight, preferably less than 0.5% by weight, particularly preferably less than 0.1% by weight and particularly preferably 0% by weight, of dialkyl phthalates.
A further requirement is that the adhesion promoter compositions are clear, colourless and free from solids or precipitates, do not comprise any highly volatile constituents, i.e. organic compounds with a boiling point of 0 C to 100 C, and, for good processability, have a viscosity at 23 C that is below 30 000 mPas, preferably below 10 000 mPas and particularly preferably below 5000 mPas. The residual content of monomeric diisocyanates should be below 0.8% by weight, preferably below 0.6% by weight and particularly preferably not more than 0.5% by weight. No combination of all of these product properties has hitherto been described in the prior art.
By way of example, the adhesion promoter compositions described in WO 2005 70984 Al, based on diisononyl phthalate, are not very suitable for sensitive applications. DE 2551634 Al and EP 1378529 Al postulate that TDI-based isocyanurates which comprise isocyanate groups and are suitable as adhesion promoters can be produced in arbitrarily selective solvents, among which are also phthalate-free plasticizers. However, this is not true in practice.
Experiments carried out by the inventors revealed that arbitrarily selected phthalate-free plasticizers certainly do not lead to adhesion promoter compositions that comply with all of the requirements described. This is also true for the plasticizers described in DE
102007034977, which are based on alkylsulphonic esters of phenol (ASE) and are marketed with the trademark Mesamoll . DE 3041732 Al describes, as adhesion promoters, suitable solutions of isocyanurates which comprise isocyanate groups but which are produced from MDI. These solutions are unsuitable for the abovementioned reasons.
Object of the invention It was therefore an object of the present invention to provide, as adhesion promoters, suitable compositions of isocyanurates comprising isocyanate groups, which, although comprising phthalate-free plasticizers, achieve the level of the phthalate-containing adhesion promoters from W02005/70984 Al in respect of their mechanical properties, e.g. bond strengths. The isocyanurates comprising isocyanate groups are to be based on isomer mixtures of TDI that are available on a large industrial scale. The compositions are to be clear and almost colourless, their viscosity at 23 C is to be <30 000 mPas, preferably below 10 000 mPas and particularly preferably below 5000 mPas, and the content of free TDI (all isomers) is to be below 0.8% by weight, preferably below 0.6% by weight and particularly preferably not more than 0.5% by weight. The volatility of the plasticizer used should be no higher than that of isononyl benzoate.
Date Recue/Date Received 2022-11-21

- 4 -Volatility of the plasticizer The volatility of the plasticizer used should not be less favourable than that of isononyl benzoate (INB). INB is accepted worldwide in relation to volatility as a carrier for isocyanurate in its capacity as active substance in adhesion promoter. However, higher volatility is undesirable. The volatility of a substance is determined here by thermogravimetric analysis (TGA).
Achievement of the object The object is achieved by, and the present invention therefore provides, compositions comprising:
a) isocyanurates comprising isocyanate groups and b) benzyl alkyl adipate, where the ratio by weight of a) to b) is in the range of 1:1 to 1:8, preferably of 1:1.2 to 1:4 and particular preferably of 1:1.5 to 1:2,5.
In a preferred embodiment, the benzyl alkyl adipate bears, as alkyl group, a branched or unbranched C6 to C16 alkyl group, preferably an unbranched or branched octyl group and most preferably an isooctyl group.
Very particular preference is given to the use of benzyl octyl adipate as component b).
In a preferred embodiment of the invention, the compositions comprise 20% to 35% by weight of isocyanurates comprising isocyanate groups and 80% to 65% by weight of benzyl octyl adipate.
In another preferred embodiment, the compositions comprise, based on the total mass of the composition, up to 50% by weight, preferably 0.1% to 40% by weight, of a diluent. This is preferably a diluent from the group comprising alkyl acetate, preferably butyl acetate, ethyl acetate, propyl acetate, N-alkylpyrrolidone, N-octylpyrrolidone, N-decylpyrrolidone, DM F, acetone, alkyl benzoates, with preference benzyl benzoate, paraffins, white oils, and low-aromatic-content aliphatics, and mixtures of these substances.
Isocyanurates which comprise isocyanate groups and which can be used advantageously as component a) are obtainable by trimerization of a mixture of isomeric diisocyanatotoluenes comprising 2,4-diisocyanatotoluene and 2,6-diisocyanatotoluene.
Isocyanurates which comprise isocyanate groups and which are preferably used as component a) are obtainable by trimerization of a mixture of 65% to 95% by weight of Date Recue/Date Received 2022-11-21

- 5 -2,4-diisocyanatotoluene and 5% to 35% by weight of 2,6-diisocyanatotoluene, where the percentages by weight are respectively based on the total quantity of diisocyanatotoluenes.
The production of component a) can be achieved by trimerization of the diisocyanate mixtures by known processes of the type described by way of example in WO 2005 70984 Al.
The trimerization is preferably carried out in the presence of plasticizer component b).
The present invention also provides a process for the production of the compositions of the invention, in which diisocyanates are trimerized in the presence of the benzyl alkyl adipate b) to give the isocyanurates a) comprising isocyanate groups.
The trimerization reaction typically takes place in the temperature range of 40 to 140 C, preferably 40 to 80 C. The trimerization is terminated when the content of monomeric diisocyanates in the reaction mixture is 0.8% by weight, preferably 0.6% by weight, and particularly preferably 0.5% by weight or less.
The above termination can be achieved by complete or partial deactivation of the catalyst, for example by thermal decomposition of the catalyst or addition of a reaction terminator. Protic .. acids, acyl chlorides or methylating compounds can be used as reaction terminators. It is particularly preferable to use alkyl phosphates, in particular dibutyl phosphate, or methyl toluenesulphonate. When a reaction terminator is used, the quantity used thereof is typically 0.22% to 4% by weight, preferably 0.1% to 2% by weight, particularly preferably 0.2% to 1%
by weight, based on the total quantity of diisocyanates used. The product then typically comprises 3% to 7% by weight of isocyanate groups, preferably 4.5% to 6%.
In a preferred embodiment, diisocyanates used in the process of the invention are diisocyanatotoluenes, particularly preferably mixtures consisting essentially of 2,4-TDI and 2,6-TDI that are available on a large industrial scale. The mixtures are mixtures of isomeric diisocyanatotoluenes comprising 65% to 95% by weight of 2,4-diisocyanatotoluene and 5% to 35% by weight of 2,6-diisocyanatotoluene and are produced with catalysis. The TDI isomer mixtures particularly preferably comprise 75% to 85% by weight of 2,4-TDI in a mixture with 15% to 25% by weight of 2,6-TDI. An example of these TDI isomer mixtures that are particularly preferably to be used is the product Desmodur T80, obtainable commercially from Covestro AG.
Production of component a) can use a catalyst which serves for the initiation and acceleration of the trimerization reaction and which also, at relatively high temperatures, leads to selective incorporation of TDI. These catalysts have phenolic OH groups and N,N-dialkylaminomethyl Date Recue/Date Received 2022-11-21

- 6 -groups attached to aromatic systems (alkyl: C1-C3 alkyl chain and/or alkylene chain having 1 to 18 carbon atoms optionally separated by oxygen or by sulphur).
These groups can be distributed over a plurality of molecules or positioned on one or more aromatic rings. Compounds used as catalyst systems are preferably those that comprise not only hydroxy but also aminomethyl groups in a molecule.
It is particularly preferable to use systems in which C1-C3 dialkylaminomethyl groups are positioned ortho to aromatic hydroxy groups.
The synthesis of Mannich bases suitable as catalysts is described by way of example in DE 25 51 634 Al and WO 2005 70984 Al. Mannich bases to be used with preference are those based on phenyl, p-isononylphenol or bisphenol A, these being obtained by reaction with dimethylamine and formaldehyde, for example according to DE-A 2 452 531 or Synth.
Commun. (1986), 16, 1401-9. In particular, preference is given to Mannich bases based on phenol or bisphenol A.
The catalysts to be used are used as pure substance or in solution, preferably in a plurality of small portions or continuously.
The compositions of the invention are clear, colourless or almost colourless liquids which have surprising stability in storage, and even after storage for several weeks have no tendency towards discoloration or crystallization or towards formation of precipitates or phase separation. Before and after storage they moreover feature extremely low content of free TDI
.. (i.e. monomeric diisocyanatotoluenes) ¨ a particular advantage of the compositions of the invention because of the relatively low boiling point of this toxicologically questionable d iisocyan ate.
Comparative Examples 1 to 6 set out below therefore not only reveal that the object underlying this invention cannot be achieved with arbitrarily selected phthalate-free plasticizers but moreover prove that the present invention also provides a process that can advantageously produce the combination of plasticizer and isocyanurates comprising isocyanate groups which, in the form of adhesion promoter compositions, provides the required properties.
Use of the compositions of the invention The compositions of the invention are suitable as adhesion promoters, particularly for coatings made of plasticized PVC, or as adhesion-promoting additions for PVC
plastisols. The person skilled in the art understands the expression "PVC plastisols" to mean liquid dispersions of PVC in a plasticizer which gel for example through heating to a relatively high temperature and Date Recue/Date Received 2022-11-21

- 7 -therefore can be used for the production of plasticized PVC. The compositions of the invention can be used particularly advantageously as adhesion promoters between substrates made of synthetic fibres having groups reactive towards isocyanate groups, e.g.
polyamide or polyester fibres, and PVC plastisols or flexible-PVC melts. It is self-evident that the solutions of the invention can also be used to improve the adhesion of plasticized PVC on areal substrates, for example on foils.
The compositions of the invention are therefore particularly suitable as adhesion promoters for coating compositions based on plasticized PVC. For the purposes of the present invention, the expression "coating compositions based on plasticized PVC" encompasses not only coating compositions comprising plastisols but also coating compositions which, when applied to the substrate, take the form of compositions comprising molten flexible PVC; the former are preferred here.
Particularly suitable as substrates to be coated are textiles such as woven fabrics made of natural fibres, of synthetic fibres, or of glass fibres. Particularly suitable synthetic fibres are .. polyamides and polyester fibres. Leather can moreover be used as substrate.
The compositions of the invention can be used for the production of substrates with coatings comprising, or consisting of, plasticized PVC. If the coating does not consist of plasticized PVC, it typically comprises at least 50% by weight of the same, preferably at least 75% by weight and particularly preferably 90% by weight to 99% by weight, alongside additional substances regarded by the person skilled in the art as customary for PVC coatings. The compositions of the invention can by way of example be applied here to the substrates to be coated by printing, doctor-system methods, screening or spraying, or by immersion. As required by the product to be produced, one or more adhesion-promoter-free PVC layers is/are then applied, for example in the form of plastisols or by extrusion coating or hot-melt roll coating, or by lamination, to the substrate surfaces thus treated. The compositions of the invention can also particularly preferably be added to a PVC plastisol before it is applied.
Quantities are used on the compositions of the invention are usually such that, based on plasticizer-free PVC of the coating composition, 0.5% to 40% by weight, preferably 2% to 15%
by weight, of isocyanurates comprising isocyanate groups are present. However, the solutions of the invention can also be used in any other desired quantities appropriate to the respective application sector.
Irrespective of the application method used, the production of the finished layers, i.e. the reaction of the isocyanate groups of the adhesion promoter with the substrate and the gelling of the PVC layer, is achieved in conventional manner at relatively high temperatures;
Date Recue/Date Received 2022-11-21

- 8 -temperatures used here are between 110 and 210 C, depending on the composition of the PVC layers.
The present invention also provides coatings and coated substrates for textiles or woven fabrics, these being obtainable by using the adhesion promoter compositions described above.
The compositions of the invention are suitable as adhesion promoters for coating compositions based on plasticized PVC, and therefore for the production of coatings comprising, or consisting of, plasticized PVC, i.e. in particular for the production of tarpaulins, billboards, air-supported structures and other textile structures, flexible containers, tent roofs, awnings, protective apparel, conveyor belts, flock carpets or foamed synthetic leather.
The compositions of the invention have particularly good suitability as adhesion-promoting additives for the coating of substrates having groups reactive towards isocyanate groups, in particular for coating of yarns, mats and woven fabrics made of polyester fibres or of polyamide fibres.
Inventive Example and Comparative Examples Unless otherwise noted, all parts and percentages are based on weight.
Determination of parameters Parameters determined for the products were viscosity at 23 C (VT550 rotational viscometer from Haake GmbH, Karlsruhe) and content of free TDI (gas chromatography, Hewlett Packard 5890 in accordance with DIN ISO 55956). Isocyanate content was determined in accordance with EN ISO 11909. A Mettler Toledo TGA/DSC 3+ SF/1100/189, T = RT to 400 C, 10 C/min, N2, was used to produce the TGA curves.
Starting materials for Inventive Example and Comparative Examples Desmodur T80: TDI isomer mixture consisting of 80% by weight of 2,4-TDI and 20% by weight of 2,6-TDI, Covestro AG.
Vestinol 9 DINP: Diisononyl phthalate, Evonik.
Adimoll DB: Dibutyl adipate, Lanxess Deutschland GmbH.
Adimoll DO: Dioctyl adipate, Lanxess Deutschland GmbH.
Adimoll BO: Benzyl octyl adipate, Lanxess Deutschland GmbH.
Benzoflex 2088: Mixture of diethylene glycol dibenzoate, triethylene glycol dibenzoate and dipropylene glycol dibenzoate, Velsicol Chemical Corp.
Mesamoll II: Phenyl alkanesulphonate, Lanxess Deutschland GmbH.
Date Recue/Date Received 2022-11-21

- 9 -Catalyst: DABCO TMR 30 (2,4,6-tris(dimethylaminoethyl)phenol) Reaction terminator: Dibutyl phosphate TGA:
Approximate residual Approximate residual Plasticizer Abbreviation level at 180 C level at 200 C
Dibutyl adipate DBA 31 1 Isononyl benzoate I NB 88 70 Benzyl octyl adipate BOA 96 85 Dioctyl adipate DOA 98 94 Diisononyl adipate DINA 100 98 Diisononyl phthalate DINP 100 100 Table 1: Determination of volatility of various adipates in comparison with the plasticizers INB
and DINP by TGA
Table 1 shows that at the usual processing temperatures for PVC plastisols dibutyl adipate (DBA) has already very substantially evaporated. This is unacceptable for reasons of environmental protection and workplace safety. Blistering can moreover occur in the PVC
layer; this is likewise extremely unwelcome.
Comparative Example 1 (non-inventive) DINP
180 parts by weight of Desmodur T80 were trimerized at 55 C in 378 parts by weight of Vestinol 9 DINP with 1.6 parts by weight of catalyst. The reaction was terminated after 72 hours by adding 2.6 parts by weight of reaction terminator and stirring was continued at 60 to 70 C for three hours. A clear colourless solution was obtained with 5.53%
by weight isocyanate content, viscosity at 23 C of 41 400 mPas and 0.14% by weight content of free TDI.
Comparative Example 2 (non-inventive) DBA
The volatility of dibutyl adipate was first determined by TGA (see Table 1).
It was found here that the material underwent almost complete evaporation at the usual PVC-processing temperatures of 180-210 C. This can lead to blistering at the PVC
layer and is .. therefore extremely unwelcome. No further testing was therefore carried out.
Date Regue/Date Received 2022-11-21

- 10 -Comparative Example 3 (non-inventive) Ethylene glycol dibenzoate and propylene glycol d i be nzoate 180 parts by weight of Desmodur T80 were trimerized at 50 C in 415 parts by weight of Benzoflex 2088 with 0.7 parts by weight of catalyst. The reaction was terminated after 84 hours by adding 1.7 parts by weight of reaction terminator and stirring was continued at 60 to 70 C for three hours. A clear colourless solution was obtained with 4.8% by weight isocyanate content, viscosity at 23 C of > 200 000 mPas and 1.09% by weight content of free TDI.
Comparative Example 4 (non-inventive) 2.9 parts of Mesamoll II catalyst 180 parts by weight of Desmodur T80 were trimerized at 55 C in 504 parts by weight of Mesamoll II with 2.9 parts by weight of catalyst. The reaction was terminated after 72 hours by adding 4.7 parts by weight of reaction terminator, and stirring was continued at 60 to 70 C
for three hours. A clear yellowish solution was obtained with 4.8% by weight isocyanate content, viscosity at 23 C of 11 600 mPas and 0.25% by weight content of free TDI.
Comparative Example 5 (non-inventive) 1.5 parts of Mesamoll II catalyst 180 parts by weight of Desmodur T80 were trimerized at 55 C in 378 parts by weight of Mesamoll II with 1.5 parts by weight of catalyst. The reaction was terminated after 72 hours by adding 2.6 parts by weight of reaction terminator, and stirring was continued at 60 to 70 C
for three hours. A clear yellowish solution was obtained with 5.31% by weight isocyanate content, viscosity at 23 C of > 300 000 mPas and 0.15% by weight content of free TDI.
Comparative Example 6 (non-inventive) Dioctyl adipate 180 parts by weight of Desmodur T80 were trimerized at 70 C in 534 parts by weight of Adimoll DO with 2.5 parts by weight of catalyst. The reaction was terminated after 5 hours by adding 5 parts by weight of reaction terminator and stirring was continued at 60 to 70 C for 1 hour. No clear solution was obtained. A precipitate formed after a short time. The product cannot therefore be used, and was not analysed further.
Comparative Example 1 corresponds to Example 2 from EP 1 711 546 Al, and serves to permit comparison of the properties of the adhesion promoter compositions of the invention with the prior art. Comparative Examples 4 and 5 demonstrate that increasing the quantity of catalyst does not automatically lead to a product of the invention.
Date Recue/Date Received 2022-11-21

- 11 -As the non-inventive Comparative Examples 1 to 6 moreover reveal, the selection of the plasticizer has a decisive effect on the result of the trimerization. Use of the phthalate-free plasticizers described in the prior art cannot therefore achieve the desired property combination, or can achieve this only if the TDI trimer concentration does not exceed about 27% by weight. The adhesion promoters either cannot be processed further because of their high viscosity or provide inadequate bond strengths because their TDI trimer concentration is too low.
Inventive Example 1 Benzyl octyl adipate ( = -K93) 180 parts by weight of Desmodur T80 were trimerized at 70 C in 414 parts by weight of Adimoll BO with 1.6 parts by weight of catalyst. The reaction was terminated after 12 hours by adding 3.2 parts by weight of reaction terminator, and stirring was continued at 60 to 70 C
for 1 hour. A clear colourless solution was obtained with 5.3% by weight isocyanate content, viscosity at 23 C of 1924 mPas and 0.5% by weight content of free TDI.
Performance testing and test results:
A PVC-plastisol/adhesion-promoter coating was provided to woven polyester fabric in a test system simulating industrial conditions. The bond strength of this coating was then determined on a standardized test strip. For this, a doctor system was used to coat woven polyester fabric with an adhesive coating comprising adhesion promoter. These coatings were gelled in an oven and then subjected to testing. In the testing for bond strength, two test strips were laid on top of one another (PVC side on PVC side), pressed at low pressure and 180 C, and tested in a tensile tester.
Test equipment:
Balance: Accuracy min. 0.1 g Stirrer: High-speed stirrer shaft Mathis Labcoater oven from Mathis AG Zurich Ametec LR5 K plus tensile tester Woven polyester fabric: Polyester 1100 dtex L 9/9 Z 60 standard woven fabric Woven fabric samples measuring about 40 x 25 cm were used for the test.
Date Recue/Date Received 2022-11-21

- 12 -Composition of PVC plastisol:
70 parts PVC; Vestolit B 7021 Ultra paste PVC; Vestolit GmbH; Marl 30 parts PVC Vestolit E 7031 paste PVC; Vestolit GmbH; Marl 33 parts Mesamolle ASEP plasticizer; Lanxess Deutschland GmbH
33 parts Vestino10 9 DINP plasticizer; Evonik Oxeno GmbH, Marl parts Durcal0 5 chalk; Omya GmbH; Köln 2.5 parts Baerostabe UBZ 780 RF stabilizer; Baer!ocher GmbH; Berlin 1.5 parts Kronos 0 2220 titanium dioxide; Kronos Titan GmbH; Leverkusen Test specimens:
10 Adhesive coat approximately 140 g/m2 140 C/2 min The test specimens were pressed and bonded after coating and pregelling at 140 C for 2 min at 180 C.
Dimensions: 5 cm width x 25 cm length in weft direction Testing with Ametec LR5 K plus tensile tester For production of the PVC plastisol, the starting materials listed above under "Composition of PVC plastisol" were mixed under reduced pressure in a mixer from Drais by stirring for 2.5 hours at maximum rotation rate with water cooling.
Tensile testing:
These samples were then used to determine the bond strengths in a Lloyd M 5 K
tensile tester.
The bond strength values obtained indicate the force in newtons required to peel 5 cm of the coating from the woven carrier fabric (peel test, presented in the Table as strength in N/5 cm).
The values stated in the table were obtained by averaging at least three individual measurements.
Comparative Examples and Inventive Example As revealed by the measurement results of Inventive Example 1, when the phthalate-free composition of the invention is used as adhesion promoter it provides bond strength values higher than those achieved with the phthalate-containing composition of the prior art (Comparative Example 1). The adhesion promoters from Comparative Examples 3, 5 and 6 were unsuitable for further processing because they either had excessive viscosity or led to Date Recue/Date Received 2022-11-21

- 13 -precipitates. The compositions of Comparative Examples 4 and 5 moreover had a disadvantageous yellow colouring. Another unexpected finding was that among the adipate class of substances it was only the benzyl octyl adipate of the invention that exhibited unexpectedly good efficacy; the two other products from this substance class either exhibited precipitates or were much too volatile.
Test results:
Example Volatility of Viscosity Strength of plasticizer adhesion N/5 cm Comparative Example 1 low 41 000 mPas 156 DINP
Comparative Example 2 too high not tested not tested DBA
Comparative Example 3 sufficiently low > 200 000 mPas could not be tested Benzoflex 2088 Comparative Example 4 low 11 600 mPas 148 2.9 parts of Mesamoll II
catalyst Comparative Example 5 low > 300 000 mPas could not be tested 1.5 parts of Mesamoll II
catalyst Comparative Example 6 sufficiently low precipitated not tested Dioctyl adipate Inventive Example 1 sufficiently low 1900 mPas 206 Benzyl octyl adipate Date Regue/Date Received 2022-11-21

Claims

Patent claims

1. Compositions comprising:
a) isocyanurates comprising isocyanate groups and b) benzyl alkyl adipate, where the ratio by weight of a) to b) is in the range of 1:1 to 1:8, preferably of 1:1.2 to 1:4 and particular preferably of 1:1.5 to 1:2,5.

2. Compositions according to Claim 1, wherein the benzyl alkyl adipate has, as alkyl group, a branched or unbranched C6 tO Ci6 alkyl group, preferably an unbranched or branched octyl group, most preferably an isooctyl group.

3. Compositions according to Claim 1 or 2, wherein the isocyanurates comprising isocyanate groups are obtainable by trimerization of a mixture of isomeric diisocyanatotoluenes comprising 2,4-d iisocyanatotoluene and 2,6-diisocyanatotoluene.

4. Compositions according to one or more of Claims 1 to 3, wherein the isocyanurates comprising isocyanate groups are obtainable by trimerization of a mixture of 65% to 95% by weight of 2,4-diisocyanatotoluene and 5% to 35% by weight of 2,6-diisocyanatotoluene, where the percentages by weight are respectively based on the total quantity of diisocyanatotoluenes.

5. Compositions according to one or more of Claims 1 to 4, comprising, based on the total mass of the composition, up to 50% by weight of a diluent, preferably a diluent selected from the group of alkyl acetate, preferably butyl acetate, ethyl acetate, propyl acetate, N-alkylpyrrolidone, N-octylpyrrolidone, N-decylpyrrolidone, DMF, acetone, alkyl benzoates, with preference benzyl benzoate, paraffins, white oils, and low-aromatic-content aliphatics, and mixtures of these substances.

6. Use of the compositions according to one or more of Claims 1 to 5 as adhesion promoters for coating compositions based on plasticized polyvinyl chloride.

7. Use according to Claim 6, wherein the coating composition comprises at least one PVC
plastisol.

8. Use according to Claim 5 or 6, for the production of substrates with coatings comprising or consisting of plasticized polyvinyl chloride.

9. Use according to Claim 8, wherein the coated substrates are tarpaulins, billboards, air-supported structures and other textile structures, flexible containers, tent roofs, awnings, protective apparel, conveyor belts, flock carpets or foamed synthetic leather.

10. Use according to one or more of Claims 8 and 9, wherein the substrates are textile, woven fabrics or leather.

11. Use according to Claim 10, wherein the woven fabrics are textile polyester woven fabrics or textile polyamide woven fabrics.

12. Process for the production of the compositions according to one or more of Claims 1 to 5, wherein diisocyanates are trimerized in the presence of the alkyl adipate b) to give the isocyanurates a) comprising isocyanate groups.

13. Process according to Claim 12, in which the trimerization takes place in the temperature range of 40 to 140 C and is terminated when the content of the diisocyanates used in the reaction mixture is 0.8% by weight, preferably 0.6% by weight and particularly preferably 0.5% by weight or less.

14. Process according to Claim 12 or 13, in which diisocyanates used are a mixture of isomeric diisocyanatotoluenes, comprising 2,4-diisocyanatotoluene and 2,6-diisocyanatotoluene.

15. Coating composition comprising a composition according to one or more of Claims 1 to and at least one PVC plastisol.