New phthalate-free isocyanurate composition and use thereof

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

[0001] New phthalate-free isocvanurate composition and its use

[0002] The present invention relates to the technical field of adhesion promoters, in particular adhesion promoters for coating materials based on plasticized PVC, and provides phthalate-free, low-monomer, low-viscosity and low-volatility compositions that are particularly suitable as adhesion promoters.

[0003] State of the art

[0004] It is known to improve the adhesion of plasticized PVC to substrates by adding an isocyanate-containing adhesion promoter to the plasticized PVC. Such improved adhesion is important, for example, when manufacturing synthetic textiles coated with PVC. Isocyanurates containing isocyanates are preferably used as adhesion promoters; these can be prepared from diisocyanates by oligomerization, especially trimerization. Commercially available mixtures of isomeric diisocyanatotoluenes (TDIs), consisting mainly of 2,4-diisocyanatotoluene (2,4-TDI) and 2,6-diisocyanatotoluene (2,6-TDI), are typically used as diisocyanates. These can be easily and almost completely converted into isocyanate-containing isocyanates.Near-complete conversion is necessary for reasons of occupational and product safety and EU regulations, which is why the residual diisocyanate content in the adhesion promoter composition is kept below 0.5% by weight. Diisocyanatodiphenylmethanes (MDI), which are also readily available, are less suitable because they are more difficult to trimerize than TDI and can thus lead to an undesirably high residual diisocyanate content. Furthermore, isocyanate-containing isocyanate-based isocyanates containing MDI exhibit poor solubility and tend to crystallize.

[0005] Isocyanate group-containing isocyanurates

[0006] Isocyanate group-containing isocyanates are particularly easy to handle as adhesion promoters when used in solution in a plasticizer. The production of isocyanate group-containing isocyanates from TDI preferably takes place within the plasticizer used as a solvent. Such adhesion promoters and plasticizer-containing adhesion promoter compositions, their production, and their application are described, for example, in DE2419016 A1 (GB1455701 A) or in WO2011 / 095569. Plasticizers and plasticized PVC

[0007] Plasticizers within the meaning of the present invention are typically non-volatile or only slightly volatile organic compounds that do not form a covalent bond with PVC and lower its glass transition temperature. Mixing with the plasticizer transforms the inherently hard and brittle PVC into a soft, ductile material known to those skilled in the art as plasticized PVC or flexible PVC. Plasticized PVC typically exists as a flexible solid at room temperature. Suitable plasticizers are known to those skilled in the art. Typical plasticizers include, for example, esters of phthalic acid, terephthalic acid, sebacic acid, trimellitic acid, alkanesulfonic acid, citric acid, or benzoic acid with alcohols. Plasticized PVC contains significant amounts of such plasticizers, typically ranging from 10 wt.% to over 50 wt.% of the total mass of the plasticized PVC.Under unfavorable usage conditions, the plasticizer can migrate to the surface or transfer into adjacent materials. Therefore, the use of plasticized PVC poses a risk of contamination of humans and the environment with the plasticizer. In light of this problem, there has recently been an increasing demand for plasticizers to be harmless to humans and non-bioaccumulative.

[0008] Short-chain phthalates as plasticizers

[0009] According to the REACH Regulation in the European Union, the plasticizers di(2-ethylhexyl) phthalate, dibutyl phthalate, and benzyl butyl phthalate are on the SVHC list (substances of very high concern). Furthermore, the plasticizers diisononyl phthalate, diisodecyl phthalate, and di-n-octyl phthalate are no longer permitted in toys or baby articles that can be put in the mouth by children. Given these restrictions, which can appear confusing and unsettling to some consumers, many manufacturers are switching to completely eliminating all phthalate-containing plasticizers and their isomers from the production of plasticized PVC. Therefore, there is a need for phthalate-free plasticizers that achieve the same level of performance as phthalate-based plasticizers in terms of processability and performance characteristics.

[0010] Phthalate-free plasticizers

[0011] In connection with the present invention, plasticizers are referred to as phthalate-free plasticizers if they contain less than 1.0 wt.%, preferably less than 0.5 wt.%, particularly preferably less than 0.1 wt.% and particularly preferably no phthalic acid dialkyl esters at all, based on the plasticizer content.

[0012] Phthalate-free adhesion promoter compositions

[0013] The absence of phthalate-containing plasticizers is now also required for adhesion promoter compositions containing plasticizers, particularly for sensitive applications involving, for example, skin contact. Therefore, there is a great need for adhesion promoter compositions that do not contain phthalates but still exhibit the good adhesion properties of phthalate-containing adhesion promoter compositions from the prior art. In connection with the present invention, adhesion promoter compositions are defined as those that contain – based on their total mass – less than 1.0 wt.%, preferably less than 0.5 wt.%, particularly preferably less than 0.1 wt.%, and most preferably no phthalic acid dialkyl esters at all.

[0014] Furthermore, it is required that the adhesion promoter compositions be clear, colorless, and free of solids or precipitates, contain no highly volatile components (i.e., organic compounds with a boiling point of 0°C to 100°C), and, for good processability, have a viscosity at 23°C of less than 30,000 mPas, preferably less than 10,000 mPas, and particularly preferably less than 5,000 mPas. The residual content of monomeric diisocyanates should be less than 0.8 wt%, preferably less than 0.6 wt%, and particularly preferably not more than 0.5 wt%. A combination of all these product properties has not been described in the prior art.

[0015] Thus, the adhesion promoter compositions based on diisononyl phthalate described in WO 2005 70984 A1 are less suitable for sensitive applications. DE 2551634 A1 and EP 1378529 A1 postulate that isocyanate-containing isocyanates based on TDI, suitable as adhesion promoters, can be produced in any solvent, including phthalate-free plasticizers. However, this does not correspond to reality. Experiments by the inventors showed that by no means do just any phthalate-free plasticizers lead to adhesion promoter compositions that meet all the described requirements. This also applies to the plasticizers based on alkanesulfonic acid esters of phenol (ASE) described in DE 102007034977, which are marketed under the trade name Mesamoll. ®to be distributed. DE 3041732 A1 describes suitable solutions of isocyanate-containing isocyanurates as adhesion promoters, which, however, are produced from MDI. These solutions are unsuitable for the reasons mentioned above. Object of the invention

[0016] The object of the present invention was therefore to provide suitable compositions of isocyanate-containing isocyanurates as adhesion promoters, which, although containing phthalate-free plasticizers, achieve the level of the phthalate-containing adhesion promoter compositions from W02005 / 70984 A1 in their mechanical properties, such as adhesion strength. The isocyanate-containing isocyanurates are to be based on industrially available isomer mixtures of TDI. The compositions are to be clear and almost colorless, their viscosity at 23°C is to be < 30,000 mPas, preferably less than 10,000 mPas, and particularly preferably less than 5,000 mPas, and the content of free TDI (all isomers) is to be less than 0.8 wt%, preferably less than 0.6 wt%, and particularly preferably not more than 0.5 wt%. The volatility of the plasticizer used should not be higher than that of iso-nonyl benzoate.

[0017] Volatility of the plasticizer

[0018] The volatility of the plasticizer used should not be lower than that of iso-nonyl benzoate (INB). INB is a globally accepted carrier of the adhesion promoter isocyanurate with respect to its volatility. However, higher volatility is undesirable. The volatility of a substance is determined by thermogravimetric analysis (TGA).

[0019] Solution to the task

[0020] The solution to the problem and thus the subject matter of the present invention are compositions containing: a) isocyanate-containing isocyanurates and b) benzyl alkyl adipate, wherein the weight ratio of a) to b) is in the range of 1 :1 to 1 :8, preferably from 1 :1 .2 to 1 :4 and particularly preferably from 1 :1 .5 to 1 :2.5.

[0021] In a preferred embodiment, the benzyl alkyl adipate carries as an alkyl group a branched or unbranched C6bis Ci6 alkyl group, preferably an unbranched or branched octyl group and most preferably an iso-octyl group.

[0022] The use of benzyl octyl adipate as component b) is particularly preferred.

[0023] In a preferred embodiment of the invention, the compositions contain 20 to 35 wt.% isocyanurates containing isocyanate groups and 80 to 65 wt.% benzyl octyl adipate. In a further preferred embodiment, the compositions contain up to 50 wt.%, preferably 0.1 to 40 wt.%, of a diluent, based on the total mass of the composition. Preferably, the diluent is from the group consisting of alkyl acetate, preferably butyl acetate, ethyl acetate, propyl acetate, N-alkylpyrrolidone, N-octylpyrrolidone, N-decylpyrrolidone, DMF, acetone, alkyl benzoates, preferably benzyl benzoate, paraffins, white oils, and low-aromatic aliphatics, as well as mixtures of these substances.

[0024] Advantageously, a) isocyanate group-containing isocyanurates can be used as a component, which are obtainable by trimerization of a mixture of isomeric diisocyanatotoluenes containing 2,4-diisocyanatotoluene and 2,6-diisocyanatotoluene.

[0025] Preferably, as component a) isocyanate group-containing isocyanurates are used, which can be obtained by trimerization of a mixture of 65 to 95 wt.% 2,4-diisocyanatotoluene and 5 to 35 wt.% 2,6-diisocyanatotoluene, wherein the wt. percent are based on the total amount of diisocyanatotoluenes.

[0026] The production of component a) can be carried out by trimerization of the diisocyanate mixtures according to known methods, such as those described in WO 2005 70984 A1.

[0027] Trimerization is preferably carried out in the presence of the plasticizer component b).

[0028] The present invention also relates to a process for producing the compositions according to the invention, in which diisocyanates are trimerized in the presence of the benzyl alkyl adipate b) to the isocyanate group-containing isocyanurates a).

[0029] 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 wt%, preferably 0.6 wt%, and particularly preferably 0.5 wt% or less.

[0030] Such a termination can be achieved by complete or partial deactivation of the catalyst, for example, by thermal decomposition of the catalyst or by adding a reaction inhibitor. Protic acids, acid chlorides, or methylating compounds can be used as reaction inhibitors. Alkyl phosphates, especially dibutyl phosphate or methyl toluenesulfonate, are particularly preferred. Typically, when using a reaction inhibitor, it is added in an amount of 0.02 to 4 wt.%, preferably 0.1 to 2 wt.%, and particularly preferably 0.2 to 1 wt.%, based on the total amount of diisocyanate used. The product then typically contains 3 to 7 wt.%, preferably 4.5 to 6 wt.%, isocyanate groups.

[0031] In a preferred embodiment, diisocyanates, particularly mixtures consisting essentially of 2,4-TDI and 2,6-TDI, are used as diisocyanates in the process according to the invention. These mixtures are blends of isomeric diisocyanatotoluenes containing 65 to 95 wt% 2,4-diisocyanatotoluene and 5 to 35 wt% 2,6-diisocyanatotoluene and are produced under catalysis. Particularly preferably, the TDI isomer mixtures contain 75 to 85 wt% 2,4-TDI in the mixture with 15 to 25 wt% 2,6-TDI. An example of these particularly preferred TDI isomer mixtures is the commercially available product Desmodur® T80 from Covestro AG.

[0032] For the production of component a), a catalyst can be used to initiate and accelerate the trimerization reaction, which also leads to the selective incorporation of TDI at higher temperatures. Such catalysts have N,N-dialkylaminomethyl groups and phenolic OH groups bonded to aromatics (alkyl: C1-C3 alkyl chain and / or alkylene chain with 1 to 18 carbon atoms, optionally separated by oxygen or sulfur).

[0033] These groups can be distributed across multiple molecules or positioned on one or more aromatic rings. Compounds containing both hydroxyl and aminomethyl groups within a single molecule are preferably used as catalyst systems.

[0034] Systems in which C1-C3 dialkylamino methyl groups are positioned in the ortho position to aromatic hydroxyl groups are particularly preferred.

[0035] The synthesis of Mannich bases suitable as catalysts is described, for example, in DE 25 51 634 A1 and WO 2005 70984 A1. Preferred Mannich bases are those based on phenol, p-isononylphenol, or bisphenol A, which are obtained by reaction with dimethylamine and formaldehyde, e.g., according to DE-A 2 452 531 or Synth. Commun. (1986), 16, 1401-9. Mannich bases based on phenol or bisphenol A are particularly preferred.

[0036] The catalysts to be used are employed as a pure substance or in solution, preferably in several small portions or continuously.

[0037] The compositions according to the invention are clear, colorless or almost colorless liquids with surprising storage stability, which even after several weeks of storage do not tend to discolor, crystallize, form precipitates or undergo phase separation. Furthermore, they are characterized before and after storage by an extremely low content of free TDI (i.e., monomeric diisocyanototoluenes), which is a particular advantage of the compositions according to the invention because of the relatively low boiling point of this toxicologically problematic diisocyanate.

[0038] The comparative examples 1 to 6 listed below thus not only show that the problem underlying this invention cannot be solved with just any phthalate-free plasticizers, but also demonstrate that the present invention provides a method with which the combination of plasticizer and isocyanate-containing isocyanurates can be advantageously produced, which, as adhesion promoter compositions, provides the required properties.

[0039] Use of the compositions according to the invention

[0040] The compositions according to the invention are suitable as adhesion promoters, especially for coatings made of plasticized PVC, or as adhesion-promoting additives for PVC plastisols. PVC plastisols are understood by those skilled in the art to be liquid dispersions of PVC in a plasticizer, which, for example, gel upon heating to a higher temperature and can thus be used for the production of plasticized PVC. The compositions according to the invention can be used particularly advantageously as adhesion promoters between substrates made of synthetic fibers with groups reactive towards isocyanate groups, such as polyamide or polyester fibers, and PVC plastisols or soft PVC melts. Naturally, the adhesion of plasticized PVC to flat substrates, such as films, can also be improved with the solutions according to the invention.

[0041] The compositions according to the invention are therefore particularly suitable as adhesion promoters for coating materials based on plasticized PVC. For the purposes of this invention, the term "coating materials based on plasticized PVC" includes both coating materials containing plastisols and coating materials that are applied to the substrate in the form of compositions containing molten soft PVC, with the former being preferred.

[0042] Suitable substrates for coating include textiles such as fabrics made of natural, synthetic, or glass fibers. Polyamide and polyester fibers are particularly suitable among synthetic fibers. Leather can also be used as a substrate.

[0043] The compositions according to the invention can be used to produce substrates with coatings containing or consisting of plasticized PVC. If the coating does not consist of plasticized PVC, it typically contains at least 50% by weight, preferably at least 75% by weight, and particularly preferably 90% to 99% by weight of the same, in addition to the additives for PVC coatings that are customary for those skilled in the art. The compositions according to the invention can, for example, be printed, squeegeed, screened, sprayed, or applied to the substrates to be coated by dipping. Depending on the article to be manufactured, one or more adhesion promoter-free PVC layers, e.g., as plastisols, by extrusion or melt roller coating, or by lamination, are applied to the substrate surfaces thus pretreated.Particularly preferably, the compositions according to the invention can also be added to a PVC plastisol before its application.

[0044] The compositions according to the invention are typically used in such quantities that, based on plasticizer-free PVC of the coating mass, 0.5 to 40 wt.%, preferably 2 to 15 wt.%, isocyanate-containing isocyanates are present. However, the solutions according to the invention can also be used in any other quantities adapted to the respective field of application.

[0045] The production of the finished layers, i.e. the reaction of the isocyanate groups of the adhesion promoter with the substrate and the gelation of the PVC layer, takes place in the usual way at higher temperatures, regardless of the type of application, with temperatures between 110 and 210°C being used depending on the composition of the PVC layers.

[0046] A further object of the present invention is coatings and coated substrates for textiles or fabrics, which are obtainable using the adhesion promoter compositions described above. The compositions according to the invention are suitable as adhesion promoters for coating materials based on plasticized PVC, and thus for the production of coatings containing 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 clothing, conveyor belts, flocked carpets or foam artificial leather.

[0047] The compositions according to the invention are particularly well suited as adhesion-promoting additives for coating substrates with groups reactive towards isocyanate groups, especially for coating yarns, mats and fabrics made of polyester or polyamide fibers.

[0048] Example and comparative examples

[0049] Unless otherwise stated, all parts and percentages refer to weight. Determining the key data

[0050] Product characteristics determined by viscosity at 23°C (Haake GmbH VT550 rotational viscometer, Karlsruhe) and free TDI content (gas chromatography, Hewlett Packard 5890 according to DIN ISO 55956). Isocyanate content was determined according to EN ISO 11909. TGA profiles were generated using a Mettler Toledo TGA / DSC 3+ SF / 1100 / 189, temperature range from room temperature to 400°C, flow rate of 10°C / min, and nitrogen content.

[0051] Starting materials for example and comparative examples

[0052] Desmodur® T80: TDI isomer mixture of 80 wt% 2,4-TDI and 20 wt% 2,6-TDI, Covestro AG. Vestinol® 9 DINP: Diisononyl phthalate, Evonik.

[0053] Adimoll® DB: Dibutyl adipate, Lanxess Deutschland GmbH.

[0054] Adimoll® DO: Dioctyl adipate, Lanxess Deutschland GmbH.

[0055] Adimoll® BO: Benzyl octyl adipate, Lanxess Deutschland GmbH.

[0056] Benzoflex® 2088: Mixture of diethylene glycol dibenzoate, triethylene glycol dibenzoate and dipropylene glycol dibenzoate, Velsicol Chemical Corp.

[0057] Mesamoll® II: Alkanesulfonic acid phenol esters, Lanxess Deutschland GmbH. Catalyst: DABCO TMR 30 (2,4,6-Tris(dimethylaminoethyl)phenol). Reaction stopper: Dibutyl phosphate.

[0058] TGA:

[0059] Table 1: Determination of the volatility of various adipates compared to the plasticizers INB and DINP using TGA

[0060] Table 1 shows that dibutyl adipate (DBA) has largely evaporated at the usual processing temperatures for PVC plastisols. This is unacceptable for environmental and occupational safety reasons. Furthermore, it can lead to blistering in the PVC layer, which is also highly undesirable.

[0061] Comparative Example 1 (not according to the invention): 180 parts by weight of DINP Desmodur® T80 were trimerized at 55°C in 378 parts by weight of Vestinol® 9 DINP with 1.6 parts by weight of catalyst. After 72 hours, the reaction was stopped by adding 2.6 parts by weight of reaction inhibitor and stirred for three hours at 60 to 70°C. A clear, colorless solution was obtained with an isocyanate content of 5.53 wt%, a viscosity at 23°C of 41,400 mPas, and a free TDI content of 0.14 wt%.

[0062] Comparison example 2 (not according to the invention) DBA

[0063] The volatility of dibutyl adipate was previously determined using TGA (see Table 1).

[0064] It was found that the material almost completely evaporates at the usual PVC processing temperatures of 180–210°C. This can lead to blistering in the PVC layer and is therefore highly undesirable. Further testing was therefore omitted. Comparative example 3 (not according to the invention): Ethylene and propylene glycol dibenzoate

[0065] 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. After 84 hours, the reaction was stopped by the addition of 1.7 parts by weight of reaction inhibitor and stirred for three hours at 60 to 70°C. A clear, colorless solution was obtained with an isocyanate content of 4.8 wt%, a viscosity at 23°C of > 200,000 mPas, and a free TDI content of 1.09 wt%.

[0066] Comparison example 4 (not according to the invention) Mesamoll® II 2.9 T Cat

[0067] 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. After 72 hours, the reaction was stopped by adding 4.7 parts by weight of reaction inhibitor and stirred for three hours at 60 to 70°C. A clear, yellowish solution was obtained with an isocyanate content of 4.8 wt%, a viscosity at 23°C of 11,600 mPas, and a free TDI content of 0.25 wt%.

[0068] Comparison example 5 (not according to the invention) Mesamoll® II 1.5 T Cat

[0069] 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. After 72 hours, the reaction was stopped by adding 2.6 parts by weight of reaction inhibitor and stirred for three hours at 60 to 70°C. A clear, yellowish solution was obtained with an isocyanate content of 5.31 wt%, a viscosity at 23°C of > 300,000 mPas, and a free TDI content of 0.15 wt%.

[0070] Comparative example 6 (not according to the invention) Dioctyl adipate

[0071] 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. After 5 hours, the reaction was stopped by adding 5 parts by weight of reaction inhibitor and stirred for 1 hour at 60 to 70°C. A clear solution was not obtained. A precipitate formed after a short time. The product is unusable in this state and was not analyzed further.

[0072] Comparative Example 1 corresponds to Example 2 from EP 1 711 546 A1 and serves to compare the properties of the adhesion promoter compositions according to the invention with the prior art. Comparative Examples 4 and 5 show that increasing the amount of catalyst does not automatically lead to a product according to the invention. As the non-inventive Comparative Examples 1 to 6 further demonstrate, the choice of plasticizer has a decisive influence on the result of the trimerization. The desired combination of properties cannot be achieved, or can only be achieved, by using the phthalate-free plasticizers described in the prior art if the TDI trimer concentration does not exceed approximately 27 wt.%. The adhesion promoters can either no longer be processed due to their high viscosity or result in insufficient adhesion strength due to their insufficient TDI trimer concentration.

[0073] Example 1 (according to the invention) Benzyl octyl adipate ( = -K93 )

[0074] 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. After 12 hours, the reaction was stopped by adding 3.2 parts by weight of reaction inhibitor and stirred for 1 hour at 60 to 70°C. A clear, colorless solution was obtained with an isocyanate content of 5.3 wt%, a viscosity at 23°C of 1,924 mPas, and a free TDI content of 0.5 wt%.

[0075] Application-related testing and test results:

[0076] In a practical testing system, polyester fabric was coated with a PVC plastisol / adhesion promoter coating. The adhesion strength of this coating was then determined using a standardized test strip. For this purpose, polyester fabric was coated with an adhesion promoter-containing coating using a squeegee. These coatings were gelled in a thermal oven and then subjected to further testing. For the adhesion strength test, two test strips (PVC side to PVC side) were placed on top of each other, pressed together at low pressure and 180°C, and tested using a tensile testing machine.

[0077] Testing facilities:

[0078] Scale: Accuracy min. 0.1 g Stirrer: High-speed rod stirrer Mathisofen Labcoater from Mathis AG Zurich Tractor unit Ametec LR5 K plus

[0079] Polyester fabric: Polyester 1100 dtex L 9 / 9 Z 60 standard fabric. Approximately 40 x 25 cm fabric samples were used for testing. Composition of the PVC plastisol:

[0080] 70 T PVC paste; Vestolit® B 7021 Ultra; Vestolit GmbH; Marl 30 T PVC paste Vestolit® E 7031; Vestolit GmbH; Marl 33 T ASEP plasticizer Mesamoll®; Lanxess Deutschland GmbH 33 T DINP plasticizer Vestinol® 9; Evonik Oxeno GmbH, Marl

[0081] 10 T Durcal® 5 chalk; Omya GmbH; Cologne

[0082] 2.5 T stabilizer Baerostab ® UBZ 780 RF; Baerlocher GmbH; Berlin

[0083] 1.5 T Titanium dioxide Kronos® 2220; Kronos Titan GmbH; Leverkusen

[0084] (T = parts) Test specimens:

[0085] Bonding coat approx. 140 g / m² 2 140°C / 2 min

[0086] After coating and pre-gelling at 140°C, the test specimens were pressed and welded for 2 minutes at 180°C.

[0087] Dimensions: 5 cm width x 25 cm length ) in thread direction Testing with Ametec LR5 K plus tensioning machine

[0088] To produce the PVC plastisol, the starting materials listed above under "Composition of PVC plastisol" were mixed in a mixer from the company Drais by stirring.

[0089] 2.5 hours at maximum speed, under water cooling and mixed in a vacuum.

[0090] Tensile test: The adhesion strengths were then determined using a Lloyd M 5 K tensile testing machine on these samples. The obtained adhesion strength values ​​indicate the force in Newtons required to peel 5 cm of the coating from the substrate (peel test, tabulated as effectiveness in N / 5 cm). The values ​​given in the table were obtained by averaging at least three individual measurements. Comparative examples and example according to the invention: As the measurement results of Example 1 show, the phthalate-free composition according to the invention, when used as an adhesion promoter, yields higher adhesion strength values ​​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 not suitable for further processing because they were either too viscous or resulted in precipitation.The compositions according to comparative examples 4 and 5 also exhibited an undesirable yellow coloration. Furthermore, it was unexpected that only the benzyl octyl adipate according to the invention, from the class of adipates, showed unexpectedly good efficacy; the other two products from this class either exhibited precipitation or were far too volatile.

[0091] Test results:

Claims

Patent claims 1. Compositions containing: a) isocyanurates containing isocyanate groups and b) benzyl alkyl adipate, wherein the weight ratio of a) to b) is in the range of 1 :1 to 1 :8, preferably from 1 :1 .2 to 1 :4 and particularly preferably from 1 :1 .5 to 1 :2 .

5.

2. Compositions according to claim 1, wherein the benzyl alkyl adipate comprises as the alkyl group a branched or unbranched C6bis Ci6 alkyl group, preferably an unbranched or branched octyl group, most preferably an iso-octyl group.

3. Compositions according to claim 1 or 2, wherein the isocyanate-containing isocyanurates are obtainable by trimerization of a mixture of isomeric diisocyantotoluenes containing 2,4-diisocyanatotoluene and 2,6-diisocyanatotoluene.

4. Compositions according to one or more of claims 1 to 3, wherein the isocyanate-containing isocyanates are obtainable by trimerization of a mixture of 65 to 95 wt% 2,4-diisocyanatotoluene and 5 to 35 wt% 2,6-diisocyanatotoluene, wherein the wt% in each case are based on the total amount 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 wt.% of a diluent, preferably a diluent from the group consisting of alkyl acetates, preferably butyl acetate, ethyl acetate, propyl acetate, N-alkylpyrrolidone, N-octylpyrrolidone, N-decylpyrrolidone, DMF, acetone, alkyl benzoates, preferably benzyl benzoate, paraffins, white oils, and low-aromatic aliphatics, as well as mixtures of these substances.

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

7. Use according to claim 6, wherein the coating material contains at least one PVC plastisol.

8. Use according to claim 5 or 6, for the manufacture of substrates with coatings containing 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 clothing, conveyor belts, flock carpets or foam artificial leather.

10. Use according to one or more of claims 8 and 9, wherein the substrates are textiles, fabrics or leather.

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

12. Method for producing the compositions according to one or more of claims 1 to 5, wherein diisocyanates are trimerized in the presence of the benzyl alkyl adipate b) to the isocyanate group-containing isocyanurates a).

13. Method according to claim 12, wherein 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 wt%, preferably 0.6 wt% and particularly preferably 0.5 wt% or less.

14. Method according to claim 12 or 13, wherein the diisocyanates used are a mixture of isomeric diisocyanatotoluenes containing 2,4-diisocyanatotoluene and 2,6-diisocyanatotoluene.

15. Coating composition comprising a composition according to one or more of claims 1 to 5 and at least one PVC plastisol.