Novel phthalate-free isocyanurate compositions and uses thereof

Abstract

The present invention relates to novel low-monomer, low-viscosity, low-volatility compositions of isocyanate-group-containing isocyanurates and phthalate-free plasticizers which, when used as adhesion promoters, produce improved adhesion; to coating agents based on plasticized PVC and also to coated substrates.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesion promoters, in particular 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. Background Art

[0002] It is known that the ability of plasticized PVC to adhere to a substrate can be improved by adding an adhesion promoter containing isocyanate groups to the plasticized PVC. For example, when it is intended to produce a synthetic textile material with a PVC covering, the improved adhesion ability is very important. The adhesion promoter preferably used is an isocyanurate, which contains isocyanate groups and can be produced from diisocyanates by oligomerization, especially trimerization. The diisocyanates used for this purpose are usually a mixture of isomeric toluene diisocyanates (TDI) mainly composed of toluene-2,4-diisocyanate (2,4-TDI) and toluene-2,6-diisocyanate (2,6-TDI), which can be easily purchased commercially. These can be easily converted almost completely into isocyanurates containing isocyanate groups. For reasons of workplace safety and product safety and EU regulations, almost complete conversion is necessary, and for these reasons, the residual content of diisocyanates in the adhesion promoter composition is kept below 0.5% by weight. Less suitable is diphenylmethane diisocyanate (MDI), which likewise has good availability, but gives a poorer trimerization than TDI and can therefore lead to undesirably high residual diisocyanate contents. In addition, MDI-based isocyanurates containing isocyanate groups exhibit poor solubility and have a tendency to crystallize.

[0003] Isocyanurates containing isocyanate groups

[0004] Isocyanurates containing isocyanate groups provide easy handling as adhesion promoters, especially when they are used in the form of solutions in plasticizers. TDI-derived isocyanurates containing isocyanate groups are preferably produced in a plasticizer used as a solvent. These adhesion promoters, adhesion promoter compositions containing plasticizers, their production and their use are described, for example, in DE 2419016 A1 (GB1455701 A) or WO 2011 / 095569.

[0005] Plasticizers and plasticized PVC

[0006] For the purpose of the present invention, plasticizers are typically organic substances with no volatility or only low volatility, and these organic substances will not covalently bond with PVC, but will reduce its glass transition temperature. Mixing with plasticizers can convert the hard and brittle PVC itself into a flexible and tough material (those skilled in the art refer to it as plasticized PVC or flexible PVC). At room temperature, plasticized PVC is generally a flexible solid. Suitable plasticizers are known to those skilled in the art. Examples of typical plasticizers are esters of phthalic acid, terephthalic acid, sebacic acid, trimellitic acid, alkanesulfonic acid, citric acid or benzoic acid with alcohol. The amount of such plasticizers present in plasticized PVC is very large, usually in the range of 10% by weight to more than 50% by weight of the total mass of plasticized PVC. Under unfavorable conditions of use, plasticizers may migrate to the surface or enter adjacent materials. Therefore, the use of plasticized PVC brings the risk of plasticizers causing pollution to people and the environment. In view of these problems, the plasticizers used in recent years have been subject to increasing requirements, requiring them not to cause harm to the human body and not to accumulate in the organism.

[0007] Short-chain phthalates as plasticizers

[0008] The REACH regulation applicable to the European Union includes the plasticizers di(2-ethylhexyl)phthalate, dibutylphthalate, benzylbutylphthalate in the SVHC (Substances of Very High Concern) list. In addition, the plasticizers diisononyl phthalate, diisodecyl phthalate and di-n-octyl phthalate can no longer be used in toys or baby products that children can put in their mouths. In view of these restrictions, which some consumers may find unclear and worrying, many manufacturers are working to avoid all phthalate-containing plasticizers and their isomers in the production of plasticized PVC. Therefore, there is a need for phthalate-free plasticizers that can achieve the performance levels of phthalate-based plasticizers in terms of processability and use characteristics.

[0009] Phthalate-free plasticizers

[0010] In the context of the present invention, the expression "phthalate-free plasticizer" is used for plasticizers which comprise less than 1.0% by weight, preferably less than 0.5% by weight, particularly preferably less than 0.1% by weight and especially preferably 0% by weight of dialkyl phthalates, based on the content of plasticizer.

[0011] Phthalate-free adhesion promoter composition

[0012] Adhesion promoter compositions containing plasticizers, in particular for sensitive applications involving, for example, skin contact, are now also required to avoid plasticizers containing phthalates. Therefore, there is a high demand for adhesion promoter compositions that do not contain phthalates but still have the good adhesion properties of adhesion promoter compositions containing phthalates in the prior art. In the context of the present invention, the expression "phthalate-free adhesion promoter composition" is used for adhesion promoter compositions that contain 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, based on the total mass of the adhesion promoter composition.

[0013] Another requirement is that the adhesion promoter composition is transparent, colorless and free of solids or precipitates, does not contain any highly volatile components (i.e. organic compounds with a boiling point of 0° C. to 100° C.), and has a viscosity of less than 30 000 mPas, preferably less than 10 000 mPas and particularly preferably less than 5000 mPas at 23° C. for good processability. The residual content of monomeric diisocyanates should be less than 0.8% by weight, preferably less than 0.6% by weight and particularly preferably not more than 0.5% by weight. To date, the combination of all these product properties has not been described in the prior art.

[0014] For example, the adhesion promoter composition based on diisononyl phthalate described in WO 2005 70984 A1 is not very suitable for sensitive applications. DE 2551634 A1 and EP 1378529 A1 assume that isocyanurates based on TDI, which contain isocyanate groups and are suitable as adhesion promoters, can be produced in arbitrarily selected solvents (including phthalate-free plasticizers). However, this is not the case in practice. Experiments carried out by the inventors have shown that arbitrarily selected phthalate-free plasticizers will definitely not produce adhesion promoter compositions that meet all the described requirements. This is also true for the plasticizers described in DE 102007034977, which are based on phenolic alkyl sulfonates (ASE) and are marketed under the trademark SULFATE. DE 3041732 A1 describes suitable solutions of isocyanurates which contain isocyanate groups but are produced from MDI as adhesion promoters. These solutions are unsuitable for the reasons mentioned above. Summary of the invention

[0015] Purpose of the Invention

[0016] The object of the present invention is therefore to provide suitable compositions of isocyanurates containing isocyanate groups as adhesion promoters which, although containing phthalate-free plasticizers, can reach the level of phthalate-containing adhesion promoters in WO 2005 / 70984 A1 in terms of mechanical properties, such as bond strength. These isocyanurates containing isocyanate groups are based on isomeric mixtures of TDI that can be obtained on a large industrial scale. These compositions will be transparent and almost colorless, with a viscosity at 23° C. of <30 000 mPas, preferably less than 10 000 mPas and particularly preferably less than 5000 mPas, and a content of free TDI (all isomers) of less than 0.8% by weight, preferably less than 0.6% by weight and particularly preferably not more than 0.5% by weight. The volatility of the plasticizer used should not be higher than that of isononyl benzoate.

[0017] Volatility of plasticizers

[0018] The volatility of the plasticizer used should not be lower than that of isononyl benzoate (INB). INB is accepted worldwide with regard to its volatility as a carrier for isocyanurates and its ability as an active substance in adhesion promoters. However, a higher volatility is undesirable. The volatility of the substances is determined here by thermogravimetric analysis (TGA).

[0019] Goal Achievement

[0020] The object is achieved by a composition comprising, and therefore the present invention provides, a composition comprising:

[0021] a) an isocyanurate containing isocyanate groups and

[0022] b) benzyl alkyl adipate,

[0023] Therein, the weight ratio of a) to b) is in the range of 1:1 to 1:8, preferably 1:1.2 to 1:4, and particularly preferably 1:1.5 to 1:2.5.

[0024] In a preferred embodiment, benzyl alkyl adipate has a branched or unbranched C 6 To C 16 Alkyl, preferably unbranched or branched octyl, and most preferably isooctyl.

[0025] Very particular preference is given to using benzyl octyl adipate as component b).

[0026] In a preferred embodiment of the present invention, the composition comprises 20 to 35% by weight of isocyanurate containing isocyanate groups and 80 to 65% by weight of benzyl octyl adipate.

[0027] In another preferred embodiment, the composition comprises up to 50% by weight, preferably 0.1 to 40% by weight, of diluent, based on the total mass of the composition. Diluents from the group comprising alkyl acetates, preferably butyl acetate, ethyl acetate, propyl acetate, N-alkyl pyrrolidones, N-octyl pyrrolidones, N-decyl pyrrolidones, DMF, acetone, alkyl benzoates, preferably benzyl benzoate, paraffin, white oil, and aliphatics with a low aromatic content, and mixtures of these substances are preferred.

[0028] Isocyanurates which comprise isocyanate groups and which can advantageously be used as component a) are obtainable by trimerization of a mixture of isomeric toluene diisocyanates comprising toluene-2,4-diisocyanate and toluene-2,6-diisocyanate.

[0029] Isocyanurates comprising isocyanate groups and preferably used as component a) are obtainable by trimerization of a mixture of 65 to 95% by weight of toluene-2,4-diisocyanate and 5 to 35% by weight of toluene-2,6-diisocyanate, these weight percentages being in each case based on the total amount of toluene diisocyanate.

[0030] The production of component a) can be achieved by trimerization of diisocyanate mixtures by known processes of the type described, for example, in WO 2005 70984 A1.

[0031] The trimerization is preferably carried out in the presence of a plasticizer component b).

[0032] The present invention also provides a process for producing the composition of the invention, wherein a diisocyanate is trimerized in the presence of benzyl alkyl adipate b) to give an isocyanurate a) comprising isocyanate groups.

[0033] The trimerization reaction typically takes place in a temperature range of 40° C. to 140° C., preferably 40° C. to 80° C. The trimerization is terminated when the content of monomeric diisocyanate in the reaction mixture is 0.8% by weight, preferably 0.6% by weight, and particularly preferably 0.5% by weight or less.

[0034] The above-mentioned 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 terminator. Protonic acids, acyl chlorides or methylated compounds can be used as reaction terminators. It is particularly preferred to use alkyl phosphates, in particular dibutyl phosphate, or methyl toluenesulfonate. When a reaction terminator is used, the amount used is typically 0.22% to 4% by weight, preferably 0.1% to 2% by weight, and particularly preferably 0.2% to 1% by weight based on the total amount of the diisocyanate used. The product then typically contains 3% to 7%, preferably 4.5% to 6% isocyanate groups by weight.

[0035] In a preferred embodiment, the diisocyanate used in the process of the invention is toluene diisocyanate, particularly preferably a mixture consisting essentially of 2,4-TDI and 2,6-TDI which are available on a large industrial scale. These mixtures are mixtures of isomeric toluene diisocyanates comprising 65 to 95% by weight of toluene-2,4-diisocyanate and 5 to 35% by weight of toluene-2,6-diisocyanate and are produced by catalysis. TDI isomer mixtures particularly preferably comprise mixtures of 75 to 85% by weight of 2,4-TDI and 15 to 25% by weight of 2,6-TDI. Examples of these TDI isomer mixtures which are particularly preferably used are the products T80, which is commercially available from Covestro AG.

[0036] The production of component a) can use catalysts which are used to initiate and accelerate the trimerization reaction and also lead to the selective incorporation of TDI at relatively high temperatures. These catalysts have phenolic OH groups and N,N-dialkylaminomethyl groups attached to an aromatic system (alkyl: C1-C3 alkyl and / or alkylene chains with 1 to 18 carbon atoms, optionally separated by oxygen or by sulfur).

[0037] These groups may be distributed over several molecules or located on one or more aromatic rings.The compounds used as catalyst system are preferably those which contain not only hydroxyl groups but also aminomethyl groups in the molecule.

[0038] Particular preference is given to using systems in which the C1-C3 dialkylaminomethyl group is located in the ortho position to the aromatic hydroxy group.

[0039] The synthesis of Mannich bases suitable as catalysts is described, for example, in DE 25 51 634 A1 and WO 200570984 A1. Mannich bases preferably to be used are those based on phenyl, p-isononylphenol or bisphenol A, which are obtained by reaction with dimethylamine and formaldehyde, for example according to DE-A 2 452 531 or Synth. Commun., (1986), 16, 1401-9. Particularly preferred are Mannich bases based on phenol or bisphenol A.

[0040] The catalyst to be used is used in pure substance or in solution, preferably in several small portions or continuously.

[0041] The compositions of the invention are clear, colorless or almost colorless liquids which are surprisingly stable in storage and have no tendency to discolor or crystallize or to form precipitates or phase separation even after several weeks of storage. In addition, they also have an extremely low content of free TDI (i.e. monomeric toluene diisocyanate) before and after storage, which is a particular advantage of the compositions of the invention since this toxicologically problematic diisocyanate has a relatively low boiling point.

[0042] The comparative examples 1 to 6 listed below therefore not only show that the objects of the present invention cannot be achieved with arbitrarily selected phthalate-free plasticizers, but also demonstrate that the present invention also provides a process which can advantageously produce a combination of plasticizer and isocyanurate containing isocyanate groups, which combination in the form of an adhesion promoter composition provides the desired properties.

[0043] Use of the composition of the present invention

[0044] The composition of the invention is suitable as an adhesion promoter, in particular for coatings made of plasticized PVC, or as an adhesion-promoting additive for PVC plastisols. The person skilled in the art understands the expression "PVC plastisol" to mean a liquid dispersion of PVC in a plasticizer, which gels, for example, by heating to relatively high temperatures, and can therefore be used to produce plasticized PVC. The composition of the invention can be used particularly advantageously as an adhesion promoter between substrates made of synthetic fibers (for example polyamide or polyester fibers) having groups reactive toward isocyanate groups and PVC plastisols or flexible PVC melts. It goes without saying that the solution of the invention can also be used to improve the adhesion of plasticized PVC on planar substrates (for example foils).

[0045] 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 a substrate, are in the form of compositions comprising molten flexible PVC; the former being preferred here.

[0046] Particularly suitable as substrates to be coated are textiles, such as woven fabrics made of natural fibers, synthetic fibers or glass fibers. Particularly suitable synthetic fibers are polyamide and polyester fibers. In addition, leather can be used as a substrate.

[0047] The composition of the present invention can be used to produce substrates with coatings comprising or consisting of plasticized PVC. If the coating is not composed of plasticized PVC, it typically comprises at least 50% by weight, preferably at least 75% by weight, and particularly preferably 90% to 99% by weight of plasticized PVC, and additional substances that are considered by the skilled person to be conventional for PVC coatings. For example, the composition of the present invention can be applied to the substrate to be coated by printing, a doctor blade system method, screening or spraying, or by dipping. Depending on the needs of the product to be produced, one or more PVC layers (for example in the form of plastisols) that do not contain adhesion promoters are then applied to the substrate surface so treated either by extrusion coating or hot melt roller coating or by lamination. The composition of the present invention can also be particularly preferably added to the PVC plastisol before it is applied.

[0048] The compositions of the invention are usually used in such an amount that, based on the plasticizer-free PVC coating composition, 0.5 to 40% by weight, preferably 2 to 15% by weight, of isocyanurates containing isocyanate groups are present. However, the solutions of the invention can also be used in any other desired amount suitable for the respective field of application.

[0049] Irrespective of the application method used, the production of the finished layer (i.e. the reaction of the isocyanate groups of the adhesion promoter with the substrate and the gelation of the PVC layer) is effected in a conventional manner at relatively high temperatures; the temperatures used here are between 110° C. and 210° C., depending on the composition of the PVC layer.

[0050] The invention also provides coatings and coated substrates for textiles or woven fabrics, which can be obtained by using the above-mentioned adhesion promoter composition. The composition of the invention is suitable as an adhesion promoter for coating compositions based on plasticized PVC and is therefore used 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 clothing, conveyor belts, flocked carpets or foamed synthetic leather.

[0051] The compositions of the invention have particularly good suitability as adhesion-promoting additives for the coating of substrates having groups reactive toward isocyanate groups, in particular for the coating of yarns, felts and woven fabrics made of polyester fibers or polyamide fibers. DETAILED DESCRIPTION

[0052] Examples of the present invention and comparative examples

[0053] Unless otherwise indicated, all parts and percentages are by weight.

[0054] Parameter determination

[0055] The parameters used for product determination were the viscosity at 23° C. (VT550 rotational viscometer from Haake GmbH, Karlsruhe) and the free TDI content (gas chromatography, Hewlett Packard 5890, according to DIN ISO 55956). The isocyanate content was determined in accordance with EN ISO 11909. Using a TGA / DSC 3+SF / 1100 / 189 from Mettler Toledo, T=RT to 400° C., 10° C. / min, N 2 To produce TGA curves.

[0056] Starting materials of examples of the present invention and comparative examples

[0057] T80: TDI isomer mixture consisting of 80% by weight of 2,4-TDI and 20% by weight of 2,6-TDI, Covestro AG.

[0058] 9DINP: diisononyl phthalate, Evonik.

[0059] DB: dibutyl adipate, Lanxess Deutschland GmbH.

[0060] DO: Dioctyl adipate, LANXESS Germany GmbH.

[0061] BO: Benzyl octyl adipate, LANXESS Germany GmbH.

[0062] 2088: A mixture of diethylene glycol dibenzoate, triethylene glycol dibenzoate and dipropylene glycol dibenzoate, Velsicol Chemical Corp.

[0063] II: Phenyl alkanesulfonate, LANXESS Germany GmbH.

[0064] Catalyst: DABCO TMR 30 (2,4,6-tris(dimethylaminoethyl)phenol)

[0065] Reaction terminator: dibutyl phosphate

[0066] TGA:

[0067]

[0068] Table 1: Volatility of various adipates compared to plasticizers INB and DINP as determined by TGA

[0069] Table 1 shows that at the usual processing temperatures of PVC plastisols, dibutyl adipate (DBA) has essentially evaporated. This is unacceptable for reasons of environmental protection and workplace safety. In addition, blistering may occur in the PVC layer; this is also extremely undesirable.

[0070] Comparative Example 1 DINP (not of the present invention)

[0071] 180 parts by weight at 55°C T80 at 378 parts by weight 9DINP and 1.6 parts by weight of catalyst were trimerized. After 72 hours, the reaction was terminated by adding 2.6 parts by weight of a reaction terminator and stirring was continued for three hours at 60° C. to 70° C. A transparent, colorless solution was obtained, which had an isocyanate content of 5.53% by weight, a viscosity of 41400 mPas at 23° C. and a free TDI content of 0.14% by weight.

[0072] Comparative Example 2 (Not Inventive) DBA

[0073] The volatility of dibutyl adipate was first determined by TGA (see Table 1).

[0074] It was found here that the material evaporates almost completely at the usual PVC processing temperatures (180° C.-210° C.). This could lead to blistering of the PVC layer and is therefore extremely undesirable. Therefore, no further testing was carried out.

[0075] Comparative Example 3 (Not in the present invention) Ethylene glycol dibenzoate and propylene glycol dibenzoate

[0076] 180 parts by weight at 50°C T80 in 415 parts by weight 2088 and 0.7 parts by weight of catalyst were trimerized. After 84 hours, the reaction was terminated by adding 1.7 parts by weight of a reaction terminator and stirring was continued for three hours at 60° C. to 70° C. A clear, colorless solution was obtained with an isocyanate content of 4.8% by weight, a viscosity of >20,000 mPas at 23° C. and a free TDI content of 1.09% by weight.

[0077] Comparative Example 4 (not in the present invention) 2.9 parts II Catalyst

[0078] 180 parts by weight at 55°C T80 in 504 parts by weight II and 2.9 parts by weight of catalyst were trimerized. After 72 hours, the reaction was terminated by adding 4.7 parts by weight of a reaction terminator and stirring was continued for three hours at 60° C. to 70° C. A transparent pale yellow solution was obtained, which had an isocyanate content of 4.8% by weight, a viscosity of 11 600 mPas at 23° C. and a free TDI content of 0.25% by weight.

[0079] Comparative Example 5 1.5 parts (not of the present invention) II Catalyst

[0080] 180 parts by weight at 55°C T80 at 378 parts by weight II and 1.5 parts by weight of catalyst were trimerized. After 72 hours, the reaction was terminated by adding 2.6 parts by weight of a reaction terminator and stirring was continued for three hours at 60° C. to 70° C. A transparent, pale yellow solution was obtained, which had an isocyanate content of 5.31% by weight, a viscosity of >300,000 mPas at 23° C. and a free TDI content of 0.15% by weight.

[0081] Comparative Example 6 Dioctyl adipate (not of the present invention)

[0082] 180 parts by weight at 70°C T80 was trimerized in 534 parts by weight of Adimoll DO and 2.5 parts by weight of catalyst. After 5 hours, the reaction was terminated by adding 5 parts by weight of a reaction terminator and stirring was continued at 60° C. to 70° C. for 1 hour. No clear solution was obtained. A precipitate was formed after a short time. Therefore, the product could not be used and was not further analyzed.

[0083] Comparative Example 1 corresponds to Example 2 of EP 1 711 546 A1 and serves to compare the properties of the adhesion promoter compositions of the invention and of the prior art. Comparative Examples 4 and 5 demonstrate that increasing the amount of catalyst does not automatically lead to the product of the invention.

[0084] Furthermore, as the non-inventive comparative examples 1 and 6 show, the choice of plasticizer has a decisive influence on the trimerization result. Thus, the desired combination of properties cannot be achieved with the phthalate-free plasticizers described in the prior art, or can only be achieved when the TDI trimer concentration does not exceed about 27% by weight. These adhesion promoters either cannot be further processed due to their high viscosity or provide insufficient bond strength due to their too low TDI trimer concentration.

[0085] Example 1 of the present invention Benzyl octyl adipate (=-K93)

[0086] 180 parts by weight at 70°C T80 in 414 parts by weight BO and 1.6 parts by weight of catalyst were trimerized. After 12 hours, the reaction was terminated by adding 3.2 parts by weight of a reaction terminator and stirring was continued at 60° C. to 70° C. for 1 hour. A transparent, colorless solution was obtained with an isocyanate content of 5.3% by weight, a viscosity of 1924 mPas at 23° C. and a free TDI content of 0.5% by weight.

[0087] Performance tests and test results:

[0088] In the test system simulating industrial conditions, PVC plastisol / adhesion promoter coating is provided to woven polyester fabric.Then the bond strength of this coating is determined on the standardized test strip.For this reason, the woven polyester fabric is coated with the adhesive coating comprising the adhesion promoter using a scraper system.These coatings are gelled in an oven and then tested.In the bond strength test, two test strips are stacked together (PVC side to PVC side), pressed at low pressure and 180 ℃, and tested in a tensile tester.

[0089] Test equipment:

[0090] Balance: minimum accuracy 0.1g

[0091] Agitator: High speed agitator shaft

[0092] Mathis laboratory coater oven from Mathis AG, Zurich

[0093] Ametec LR5 K plus tensile tester

[0094] Woven polyester fabric: Polyester 1100dtex L 9 / 9Z 60 standard woven fabric

[0095] Woven fabric samples with dimensions of approximately 40 x 25 cm were used for testing.

[0096] Composition of PVC plastisol

[0097] 70 parts PVC; B 7021 Ultra paste PVC; Vestolit GmbH, Malmö;

[0098] 30 parts PVC E 7031 paste PVC; Vestolit GmbH, Malmö;

[0099] 33 servings ASEP plasticizer; LANXESS Germany GmbH

[0100] 33 servings 9DINP plasticizer; Evonik Oxeno GmbH, Marl

[0101] 10 servings 5 Chalk; Omya GmbH, Cologne;

[0102] 2.5 servings UBZ 780RF stabilizer; Baerlocher GmbH, Berlin;

[0103] 1.5 servings 2220 Titanium dioxide; Kronos Titan GmbH, Leverkusen;

[0104] Test specimen:

[0105] Adhesive coating about 140g / m 2 140℃ / 2min

[0106] After coating and pregelling at 140°C for 2 minutes, the test specimens were pressed and bonded at 180°C.

[0107] Size: 5cm width x 25cm length in weft direction

[0108] Testing with the Ametec LR5 K plus tensile tester

[0109] To produce the PVC plastisol, the starting materials listed above under “Composition of the PVC plastisol” were mixed under reduced pressure in a mixer from Drais with water cooling by stirring at maximum speed for 2.5 hours.

[0110] Tensile test:

[0111] These samples were then used to determine the bond strength in a Lloyd M 5K tensile tester. The bond strength values ​​obtained indicate the force (in Newtons) required to peel off 5 cm of the coating from the woven carrier fabric (peel test, expressed in the table as strength in N / 5 cm). The values ​​stated in the table are obtained by averaging at least three individual measurements.

[0112] Comparative Examples and Examples of the Invention

[0113] As shown by the measurement results of Example 1 of the present invention, when the composition of the present invention does not contain phthalates, it provides bond strength values ​​higher than those achieved by the prior art composition containing phthalates (Comparative Example 1). The adhesion promoters from Comparative Examples 3, 5 and 6 are not suitable for further processing because they either have too high a viscosity or produce a precipitate. In addition, the compositions of Comparative Examples 4 and 5 have an unfavorable yellow coloration. Another unexpected discovery is that among the adipate esters, only the benzyl octyl adipate of the present invention exhibits unexpectedly good efficacy; the other two products from this substance class either exhibit a precipitate or are too volatile.

[0114] Test results:

[0115]

Claims

1. A composition comprising a) isocyanurates containing isocyanate groups and b) benzyl alkyl adipate, The weight ratio of a) to b) is in the range of 1:1 to 1:

8.

2. The composition according to claim 1, in, The weight ratio of a) to b) is in the range of 1:1.2 to 1:

4.

3. The composition according to claim 1, in, The weight ratio of a) to b) is in the range of 1:1.5 to 1:2.

5.

4. The composition according to claim 1, in, The benzyl alkyl adipate has a branched or unbranched C 6 To C 16 alkyl.

5. The composition according to claim 1, in, The benzyl alkyl adipate has an unbranched or branched octyl group as the alkyl group.

6. The composition according to claim 1, in, The benzyl alkyl adipate has an isooctyl group as an alkyl group.

7. A composition according to any one of claims 1 to 6, in, These isocyanurates comprising isocyanate groups are obtainable by trimerization of a mixture of isomeric toluene diisocyanates comprising toluene-2,4-diisocyanate and toluene-2,6-diisocyanate.

8. A composition according to any one of claims 1 to 6, in, These isocyanurates comprising isocyanate groups are obtainable by trimerization of a mixture of 65 to 95% by weight of toluene-2,4-diisocyanate and 5 to 35% by weight of toluene-2,6-diisocyanate, wherein these weight percentages are each based on the total amount of toluene diisocyanate.

9. The composition according to any one of claims 1 to 6, comprising: up to 50% by weight of diluent, based on the total mass of the composition.

10. The composition according to claim 9, wherein the diluent is selected from the group consisting of alkyl acetates, N-alkyl pyrrolidones, DMF, acetone, alkyl benzoates, and aliphatic compounds with a low aromatic content, and mixtures of these substances.

11. The composition of claim 10, wherein the alkyl acetate comprises butyl acetate, ethyl acetate, propyl acetate.

12. The composition according to claim 10, wherein the N-alkyl pyrrolidone comprises N-octyl pyrrolidone, N-decyl pyrrolidone.

13. The composition according to claim 9, wherein the diluent is selected from benzyl benzoate, paraffin, white oil.

14. Use of a composition according to any one of claims 1 to 13 as an adhesion promoter for coating compositions based on plasticized polyvinyl chloride.

15. The use according to claim 14, in, The coating composition comprises at least one PVC plastisol.

16. The use according to claim 14 for producing a substrate having a coating comprising or consisting of plasticized polyvinyl chloride.

17. The use according to claim 16, in, The coated substrates are tarpaulins, billboards, flexible containers, tent roofs, awnings, protective clothing, conveyor belts, flocked carpets or foamed synthetic leather.

18. The use according to any one of claims 16 and 17, in, These substrates are textiles, woven fabrics or leather.

19. The use according to claim 18, in, These woven fabrics are woven polyester woven fabrics or woven polyamide woven fabrics.

20. A method for producing a composition according to any one of claims 1 to 13, in, The diisocyanate is trimerized in the presence of an alkyl adipate b) to give the isocyanurate a) comprising isocyanate groups.

21. The method according to claim 20, in, The trimerization takes place in a 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 or less.

22. The method according to claim 21, in, The content of the diisocyanate is 0.6% by weight or less.

23. The method according to claim 21, in, The content of the diisocyanate is 0.5% by weight or less.

24. The method according to any one of claims 20 to 23, in, The diisocyanate used was a mixture of isomeric toluene diisocyanates comprising toluene-2,4-diisocyanate and toluene-2,6-diisocyanate.

25. A coating composition comprising a composition according to any one of claims 1 to 13 and at least one PVC plastisol.

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